NCD003200383_19920622_Koppers Co. Inc._FRBCERCLA RISK_Response to Comments on the Revised Baseline Risk Assessment-OCR

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June 22, 1992
Ms. Barbara Benoy
U.S. EPA Region IV
345 Courtland Street, NW
At!anta, GA 30308
Hft:IEiVtU
SUPERFUND SECTION
Ei\SH Con~uhir-,g
anJ Engineering
:35 Nagog Park
Aclon, Ma!-s:id111scll~ 01720
(508) 6:l5-9500
[phone] (FAX)
Re: Response to comments on the Revised Baseline Risk Assessment for the Former
Koppers Company, Inc. Site, Morrisville, NC
Dear Barbara:
On behalf of Beazer East, Inc., we are submitting to you five copies of the written responses to
U.S. EPA, the State of North Carolina DEHNR, and the U.S. Fish and Wildlife Service comments
on the Revised Baseline Risk Assessment for the Former Koppers Company, Inc. Site in
Morrisville NC. We are also submitting two copies to the State of North Carolina DEHNR under
separate cover. The responses include suggested text edits where appropriate (as Attachments
to the responses) to facilitate the EPA's review of these responses. In the Attachments, all text
proposed for removal in the final draft is ·crossed-out" and all new text proposed for the final
draft is in italic type-face. All areas with any revision to the text are marked with a revision bar
on the right margin.
Please forward questions or additional comments on the proposed edits to us as soon as
possible. It is our attempt to make the July 5, 1992 submittal of the Baseline Risk Assessment
a "final" draft.
We hereby request that the responses to comments and the attachments be docketed and made
part of the Administrative Record for the Morrisville, NC Site. If you have any questions about
the responses to comments, please do not hesitate to call me or Shannon Craig at Beazer East,
Inc.
Gi1fl-4-)~
Susan L Allen, µ,-
Project Manager
cc: S. Craig, Beazer
W. Giarla, Beazer
J. Mitsak, Keystone
<p;::oeRosa;='NC"DEHNR"'
letter2.rat: 0845-006-510
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GENERAL COMMENTS -
Comment:
DRAFT
COMMENTS FROM U.S.EPA REGION IV JUNE 4, 1992
1. EPA has stated Its position on the use of degradation to adjust exposure point concentrations several times. However, there still seems to be some misunderstanding. This position will be reiterated this position a fi!lfil time. Degradation Is site-specific and it Is difficult to predict the degradation rate of a chemical without site-specific data. Unless site-specific half-life can be predicted, the risk assessment should be based on the actual site concentrations. The alternate risk calculations may be presented In an appendix and discussed In the uncertainty section. If the decision Is made to present the degradation calculations In an appendix, the exposure concentration should be based on the revised half-life of one year for phenolics which is discussed the remediation goal section.
The use of degradation to determine risk-based target clean-up levels (RBTCLs) Is unacceptable for the same reasons stated above. Degradation was used to calculate RBTCLs In the previous remediation goal document, although it was not mentioned In the text and In fact the preparers of the document had to be convinced that degradation had actually been used. Rather than recalculate the RBTCLs without using the degradation factors, as EPA requested, the revised document now admits that degradation was used and the RBTCLs are calculated Incorporating degradation. As with the risk assessment, the effect of degradation on the RBTCLs are calculated Incorporating degradation. As with the risk assessment, the effect of degradation on the RBTCLs can be discussed in the uncertainty section.
A final point Is the reality check of the half-life. The document states that, using a half-life of one year, a current concentration of 385 mg/kg would correspond to a concentration In 1975 of 3992 mg/kg. The EPA cannot reproduce this estimated original concentration. Calculations Indicate that, in this time span with the one year half-life, the original concentration would be greater than a million/ppm, i.e. an unattainable concentration greater that pure product. This does not support the literature half-life Information. Please discuss the rate decay calculation In greater detail In the written responses to these comments.
Response:
As stated in Shannon Craig's 5-May-92 letter to Barbara Benoy (see Attachment 1), EPA's initial request to remove all references to degradation from the body of the Baseline Risk Assessment report came to us in a letter dated March 30, 1992. The second draft of the Baseline Risk Assessment report was submitted to EPA on March 19, 1992. The revised clean-up levels evaluation was submitted to EPA on March 31, 1992. Notification to remove degradation from the reports was received too late for incorporation into either submittal. In the 5-May-92 letter, Beazer agreed to EPA's request to remove degradation from the main text of the Baseline Risk Assessment report and place a discussion of the potential impact of degradation in Section 7 (the Uncertainty Section) and in the Appendices to the report.
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DRAFT
Based on Beazer's written agreement to remove degradation as requested by EPA, ENSR has . proceeded with the removal of degradation from the main text of the Baseline Risk Assessment report over the past month. The report has been revised as follows:
Section /Table
Section 2
Section 5
Tables 5-1
through 5-18
Table 5-19
Section 7
Section 9
Table 9-2
Appendix E
Appendix E-4
Appendix G
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What was done
The discussion of degradation was removed from this Section. Attachment 2 shows these edits.
The text in this Section was edited to reflect non-degraded assumed risks and hazard indices. Attachment 3 contains the new text for Section 5.
Summary tables were revised with total assumed risks and hazard indices calculated without the assumption of degradation in potential soil and sediment exposures. An example of the revised Section 5 tables is shown in Attachment 4.
This table will be removed from Section 5 of the Baseline Risk Assessment and moved to Appendix E.
A discussion of the uncertainty associated with the absence of degradation was added. This new text is shown in Attachment 5.
The text in this Section was edited to reflect non-degraded RBTCLs. Attachment 6 contains the new text for Section 9.
This table was edited to remove the assumption of degradation. This Table is shown in Attachment 7. (This table is now Table 9-1.)
A discussion of the use of degradation factors in the previous drafts of the Baseline Risk Assessment was added to this Appendix. This new text is shown in Attachment 8.
Scaling tables to remove degradation from soil and sediment exposure spreadsheets were created. An example of the scaling tables and the new text describing them are shown in Attachment 9. The non-degraded values calculated in these scaling tables were used in the new Section 5 summary tables.
The text in this Appendix was edited to include RBTCLs derived assuming degradation does not occur. RBTCLs derived in previous drafts of this report were retained, however. At the request of EPA, the summary of this evaluation (presented in Section 9 of this report) focuses solely on RBTCLs derived assuming that degradation does not occur. The text edits to Appendix Gare shown in Attachment 10.
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Table G-11
Misc. Table
Edits
Appendix E-4
DRAFT
Four new tables (G-2a, G-3a, G-4a and G-5a) were created to show RBTCLs assuming no degradation occurs. These tables are shown in Attachment 11.
This table was edited to remove the assumption of degradation. This Table is shown in Attachment 12. (This table is now Table G-8.)
Several tables were re-numbered when degradation was removed from the main text of the report. These tables are shown in Attachment 13.
A statement was added to the front of this Appendix describing the use of degradation factors in the exposure spreadsheets and the removal of the degradation factors in the scaling tables. This statement is shown in Attachment 18.
The request to present degradation calculations in the Appendix using the exposure concentration based on the revised half-life for pentachlorophenol was made for the first time in the June 4, 1992 comments from EPA. It was our understanding that we could present our position on the issue of degradation in the Appendix to the Baseline Risk Assessment report if mention of the use of degradation was removed from the main text. We have completed this revision, showing the original degradation rates assumed for pentachlorophenol and dioxin in the exposure assessment and presentation of summary assumed risks and hazard indices (in Appendix E); and the potential impact of both the original and the revised degradation rates for pentachlorophenol, and the original rates for dioxin, in the clean-up levels evaluation (Appendix G). These edits are shown in the Attachments 8 and 10.
To complete the other revisions to the report requested in this set of comments in a timely fashion, we ask that this approach be considered for the final version of the document If appropriate language is placed in the Appendices that shows EPA's preference for the revised degradation rate if any is to be assumed at all. This language is also shown in Attachments 8 and 10.
In addition, as stated in Shannon Craig's 5-May-92 letter, Beazer would like the opportunity to confirm the degradation of pentachlorophenol during the Remedial Design.
The decay calculation has been removed from the main text of the report because the use of degradation to calculate RBTCls has also been removed.
Comment:
2. Another major issue concerns the use of average concentrations to determine remediation requirements. The risk assessment staff has stated several times that If the risk assessment indicates that there Is a need for remediation, any location at the site which exceeds the cleanup goal, should be remediated. Although this revision of the RBTCL document does compare the maximum along with the mean and RME concentrations with the RBTCLs, the summary discussion Is based on using average concentration. On the other hand, Section 9.0 in the BRA (Summary of the RBTCL Appendix) compares the maximum concentrations with remediation
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levels, Indicating the Intent to remediate any area which exceeds the remediation goal. Apparently, the purpose of the discussion In the RBTCL appendix Is to establish a precedent rather than to affect the remediation outcome for this site. Corrections should be made to align all document remedial discussion with the stated Agency requirements.
Response:
At our March 4, 1992 meeting with EPA, consensus was not reached on to which concentrations (i.e. average, RME or maximum) the RBTCLs should be compared. The position that we put forth at that meeting was to compare RBTCLs with average constituent concentrations because the potential exposures assumed in this report represent hypothetical long-term exposures, and it is unreasonable to assume the impossible scenario of a receptor being exposed to maximum concentrations over the long term. The position put forth by EPA at that meeting was to compare RBTCLs with maximum concentrations and that all samples exceeding the selected remedial goal would be targeted for removal. Because this issue was not resolved before the March 31, 1992 submittal of the revised clean-up levels evaluation, comparison to both average and maximum concentrations was presented in that revision. In that revision, comparison of RBTCLs to maximum concentrations was the focus of the comparison in Section 9 (i.e. the main text of the report), and comparison of RBTCLs to average and maximum concentrations was included in the Appendix to the report (Appendix G). Comparisons to RME concentrations were also included in Appendix G because the majority of the risk assessment report focuses on the evaluation of RME concentrations of constituents.
Although we remain convinced that it is scientifically appropriate and, indeed, makes common sense, to compare RBTCLs developed for hypothetical long term exposures to average constituent concentrations, we have removed the discussions comparing RBTCLs with average and RME concentrations from Section 9 and Appendix G. We propose to leave the columns of average and RME concentrations in the Appendix G tables to provide the reader with the various constituent concentrations of interest for comparison purposes.
The proposed edits to Section 9 and Appendix G are shown in Attachments 6 and 1 O, respectively.
Comment:
3. The term local resident is confusing. The offsite resident should be Identified as such to distinguish this individual from the future onslte resident.
Response:
The text and tables of the report (main report and appendices) have been re-checked and edited to identify the local resident as the local 'off-Site' resident.
Comment:
4. It was agreed In previous responses to Agency comments that qualifiers such as highly or greatly, in regard to the uncertainties associated with the BRA, will be removed from the text. Although most of these qualifiers have been removed, some still remain and should also be removed.
Response:
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DRAFT
The text of the report (main text and appendices) will be re-checked and edited to remove strong qualifiers such as 'greatly' and 'highly' from discussions of the conservative nature of the risk assessment process, for the July 2, 1992 final draft.
Comment:
5. A final general comment concerns the presence of phenollcs In offslte groundwater. Although previous sampling Indicated that 2,4,6-trichlorophenol was present above health based levels In several of the offslte wells, the results of the conformational sampling Indicated that the wells have non detectable levels of this contaminant. We recommend that additional confirmations sampling be performed, In the Remedial Design (RD) phase, to verify this and that the ROD specify that groundwater remediation of the offslte area will be contingent on the results of the RD sampling.
Response:
EPA's recommendation for additional confirmational sampling is noted and will be addressed, and a mutually agreed upon approach to the sampling will be included in the Scope Of Work for the Remedial Design workplan.
SPECIFIC COMMENTS -
Comment:
1. Page ES-7, Paragraph 5 -The discussion concerning the toxicity of dioxin Is inappropriate considering our current understanding of the dioxin reevaluation study. (See attached Journal article.) The dioxin discussion should be revised here are throughout the document.
Response:
As discussed previously with EPA, the current status of dioxin's toxicity is unclear. The EPA toxicity standards were used in the Baseline Risk Assessment Report even though there are alternate values that could be used to estimate the potential risks associated with exposure to dioxin. As reported in Appendix D to the report, these alternate values are considered more scientifically appropriate and defensible than the current EPA toxicity standard. In previous discussions with EPA, the agreement was reached that the Baseline Risk Assessment report would include language that specifically called out the current EPA re-evaluation of dioxin's potency, and that the EPA toxicity standards would be used in the estimation of assumed risk ai this Site. Because the status of EPA's re-evaluation was unknown when the previous drafts of the report were produced, language was also included in the drafts that compared the actual dioxin results of the risk assessment {based on EPA's toxicity standard), with the results had the assessment been conducted using alternate toxicity standards.
The news article by Leslie Roberts, referenced in this comment, does not state a definitive position on the potency re-evaluation for dioxin. In fact, although this article does state that the existing toxicity standards may be more accurate than previously thought, the concluding statement in this article shows that no decision has been reached:
• ... Gallo ... [states] .. .'I have no idea how it [the re-evaluation] will come out'.'
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DRAFT
Therefore, although limited evidence may support the existing EPA toxicity standards, there are also other data (as reviewed in Appendix D) that support alternate values (i.e. the human epidemiological data, including the 1990 Fingerhut study, do not support the EPA's estimation of dioxin carcinogenicity). In response to this comment, we therefore propose to edit the text throughout the report to state that 'alternate, scientifically appropriate' toxicity standards produce lower estimates of risk, rather than stating that these alternate values produce 'more scientifically appropriate' estimates of risk.
The edits to the text are shown in the Attachments to this letter.
Comment:
2. Page 2-5. Page 2 -It Is not appropriate to discuss the risk assessment conclusions about the chemicals which will require remediation in the Hazard Identification Section. Technically, the risks have not been evaluated at this point in the process.
Response:
The paragraph has been revised to remove this statement. The revisions are shown in Attachment 2.
Comment:
3. Page 2-44, Table 2-12 {Offslte Groundwater) -It ls unclear If the data summary In this table is for all offsite wells or for the near offsite wells that we agreed should be used In the risk assessment. Please clarify.
Response:
At the meeting on March 4, 1992 between EPA Region IV, NC DEHNR, Beazer, Keystone and ENSR, it was agreed that the wells that would be included in the off-Site ground water exposure evaluations would be the following: C-1, C-2, C-3, C-9, C-15, C-17, C-19, and C-20. These wells were included in the off-Site ground water exposure evaluations because these wells were thought to be most greatly influenced by constituents from the Site.
Off-Site wells selected for quantitative evaluation in the Baseline Risk Assessment reflect near-Site wells that could potentially be affected by the on-Site plume of constituents identified in the Revised RI report. The term 'off-Site' is used in the Baseline Risk Assessment so as not to confuse the reader with the 'near-Site' data set presented in the RI. The 'off-Site' wells in the Risk Assessment include some of the 'near-Site' wells in the RI; the exact listing of wells summarized in the RI and Risk Assessment analyses differ because all wells sampled in the 'near-Site' grouping were not considered to be potentially impacted by the plume of on-Site constituents and were therefore not of interest in the Risk Assessment.
The sampling locations (i.e. wells) evaluated in the off-Site ground water exposure analysis are reported on Table 2-1. The data from these wells are summarized on Table 2-12. A footnote has been added to Table 2-12 to show this information. Table 2-12 is shown in Attachment 14.
Comment:
4. Page 4-11. Section 4.3.3 and Table 4-4 and Appendix C-3 -The January 1992 version of the Dermal Exposure Assessment Report contains updated PC values which would impact the exposure intakes for several of the site contaminants of
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DRAFT
concern. These chemicals and the revised PC values are: 2-Nitrophenol -5.0E-3 cm/hr and 2,4-Dlmethylphenol -1.SE-2 cm/hr. These PC values are consistent with information presented in Appendix C-3 of the Koppers BRA. A final point concerns the PC values for 2,3,5,6-tetrachlorophenol and isopropyl ether. As I commented previously, the PC values of 2.SE-3 represents a default value for water. The text in Appendix C-3 should be corrected to reflect this information.
Response:
This comment raises two separate issues: (1) the notification of two revised dermal permeability constants (PCs), and (2) EPA Region IV's statement that the PC values for 2,3,5,6-tetrachlorophenoi and isopropyl ether (1.5E-03) is the default for water.
The January 1992 version of EPA's Guidance for Dermal Exposure Assessment contains revised PC values for 2-nitrophenol and 2,4-dimethylphenol. These revised PC values are, however, lower (i.e., less conservative) than those used in the Baseline Risk Assessment report. Because the PC values in the Baseline Risk Assessment report are more conservative than the new values recommended by EPA, and because use of the revised PC values would not significantly affect the results of the Baseline Risk Assessment, the PCs for these constituents will remain unchanged.
The text of Appendix C-3 regarding the PC value for 2,3,5,6-tetrachiorophenol and isopropyi ether, has been edited as requested by EPA.
The revisions to Appendix C-3 are shown in Attachment 15.
Comment:
5. Page 4-16, Paragraph 1 -It is not clear how the adjustment of the child's soil ingestion rate incorporates both the positive and negative standard deviation discussed in the text. Please clarify.
Response:
The discussion of soil ingestion rates in Section 4.4.1 presents the results of the review of several soil ingestion studies, one of which is a study by Clausing et al. (1987). In the Clausing study, it was estimated that nursery school aged children ingest approximately 100 mg (standard deviation = 67 mg) of soil per day. This estimate was not corrected for background trace elements. In an attempt to quantify the concentration of background trace elements, Clausing also measured trace element intake of a control group of children. Clausing then reported that after the intake of trace elements is accounted for, the estimate of a child's rate of soil ingestion decreases to 55 mg per day. It is unknown how. Clausing used the standard deviation information for the value 100 mg/day in the derivation of the recommended adjusted value of 55 mg/day. Clausing's article also did not cite a standard deviation for the value of 55 mg/day; he did say, however, that this number is statistically significant. No further explanation of how this was determined was presented in Clausing's article.
The Baseline Risk Assessment report states that the soil ingestion rate recommended by EPA, and used in this report, is almost four times the ingestion rate estimated by Clausing. This statement compares the EPA recommended soil ingestion rate (200 mg/day) with the adjusted rate recommended by Clausing (i.e. 55 mg/day). It is unknown how the standard deviation
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DRAFT
reported for the first study presented by Clausing (100 mg/day, SD = 67 mg/day) relates to the conclusions presented in his paper. At this time, we do not recommend editing the text in Section 4.4.1. If EPA would like to suggest language to better clarify the review of the Clausing study, we would be happy to review that suggestion.
Comment:
6. Page 4-47, Table 4-6 -The reference for this table appears to be Incorrect. The reference cited is for ecological assessment guidance rather than for human health exposure.
Response:
The correct reference for Table 4-6 is the Exposure Factor's Handbook, U.S. EPA 1989b from the reference list for the Baseline Risk Assessment. The table has been edited and is shown in Attachment 16.
Comment:
7. Pages 5-6 -5-8 -Comparing the risk levels to 10·5 does not give much Information. True the risks associated with exposure to surface soils in Areas B and C do exceed 1 o·•, but Area B is 1.3E-5 while Area C is 2E-2. This discussion should be more
specific. Also why is the discussion centered around 10·5? The summary should discuss pathways which produce risks which either exceed or are within the 10 .. to 1 o·• risk range.
Response:
The text of Section 5 has been edited to show how the potential assumed risks estimated in this document compare to EPA's target risk range of 1 E-04 to 1 E-06. Attachment 3 contains the edited version of the text of Section 5.
Comment;
a. Page 5-9, Paragraph 1 -Would the His have been below unity If degradation had not been used?
Response:
In the previous version of the document, only one hazard index exceeded unity, the hazard index associated with consumption of Eastern Area ground water (1.54). This hazard index was for Hypothetical On-Site Resident receptors #1 and #2. Because no degradation was assumed to occur in ground water, this result will remain unchanged in the revised document.
The removal of degradation factors in the revised document results in one additional receptor with a total hazard index exceeding unity: the Hypothetical On-Site Resident #3, HI = 1.12. This is a total hazard index; none of the pathway specific hazard indices for this receptor exceed unity. The potential exposure pathways contributing most to this hazard index are the potential consumption of Former Lagoon Area ground water as drinking water (pathway hazard index = 0.88), and the potential ingestion of and dermal contact with Area C surface soil (pathway hazard index = 0.23).
These results are presented in the revised text for Section 5 (shown in Attachment 3). It is important to note that, even if degradation is assumed to occur in soils in Area C, which would
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DRAFT
result in a total hazard index less than unity, suggesting that remediation of soil in this area may not be required based on assumed non-carcinogenic risks, the assumed carcinogenic risks associated with potential exposure to soils in this area exceed EPA's target risk range. Thus, remediation may be required regardless of the results of the analysis of assumed non-carcinogenic effects.
Comment:
9. Page 5-9. Paragraph 2 -The statement that the risks associated with undegraded PCP would Increase more than two times Is an understatement. The risks would Increase approximately 100 times. The discussion should more accurately reflect this Information.
Response:
This comment refers to a statement found in Section 5.4, Impact of Degradation Factors. Because no mention to degradation is made in the revised text for Section 5, Section 5.4 has been removed from Section 5. Therefore, this comment is no longer applicable. Text that was previously in Section 5.4 has been revised and has been included in Appendix E.
Comment:
10. Page 5-9. Paragraph 3 -The last sentence In this paragraph Is misleading. The Information should be Included that the risk for the on site residentfor PCP exposure would increase from 3E-6 to 3E-4.
Response:
See response to comment #9 above.
Comment:
11. Page 5:20. Table 5-4 -This table indicates that the HI estimated for Ingestion of 2,4-dichlorophenol In Eastern Area onslte groundwater exceeds unity. The risk summary discussion should Include this Information.
Response:
The text has been edited as requested. This edit is shown in Attachment 3.
Comment:
12. Page 7-4, Last paragraph -This discussion should be clarified. Although, technically all dioxins and furans are converted to TEFs, only the 2,3,7,8 congeners have an Impact since all other congeners are considered to have a relative potency of zero.
Response:
The text has been edited as requested. Attachment 5 shows the edits made in Section 7.
Comment:
13. Page 7-5. Paragraph 4 -The argument is made that the level of resplrable particles is probably overestimated because this information is based on PM10 levels measured at the Raleigh-Durham monitoring site and the Koppers site Is mainly
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DRAFT
vegetated or covered with pavement. A discussion of the degree of ground cover at the monitoring site would make this discussion more meaningful. Please expand.
Response:
The text of the Baseline Risk Assessment has been edited to delete the comparison between ground cover at the Beazer Site and the Raleigh and Durham monitoring sites, due to the lack of information regarding the degree of ground cover at the monitoring sites. This edit is shown in Attachment 5. ·
Comment:
14. Page 7-8, Paragraph 1 • This discussion Is misleading. The HI exceeds unity for one chemical. (See Comment 10). The breakdown for endpoints Is not needed because one chemical is responsible for the HI exceeding unity. If this were not the case, It would not be the decision of the preparers of the BRA to decide that the onsite Ingestion of groundwater is unlikely and therefore to not carry the analysis to completion. The discussion should be modified to reflect this Information.
Response:
As discussed in the response to Comment #8, one additional hazard index (HI) exceeds unity in the revised evaluation. This HI is the total HI for the Hypothetical On-Site Resident #3 (HI = 1.12). The majority of this HI is attributable to pentachlorophenol in ground water and soil, and isopropyl ether in ground water. Because the non-carcinogenic health end points for these two constituents are different, a detailed analysis of specific toxic endpoints would results in hazard indices less than unity for this receptor.
This information, and additional edits requested by EPA in this comment, were made to the text in Section 7 .1.4.1 and are shown in Attachment 5.
Comment:
15. Page 9-4, Paragraph 3 • The statement that the RBTCLs for PCP are less than the subchronlc protective concentrations Is not true for all scenarios and risk levels. In fact, Table 9-2 contains the subchronfc concentration as the commercial/Industrial human health RBTCL
Response:
Table 9-2 listed the subchronic concentration of pentachlorophenol (2250 ppm) as the commercial/industrial human health RBTCL because this value was lower than the derived RBTCL for pentachlorophenol at the 1 E-05 risk level assuming degradation occurs (4000 ppm). However, because the application of degradation has been removed from the main text of the Baseline Risk Assessment report, this paragraph is no longer in Section 9.
The revised text for Section 9 is shown in Attachment 6. Attachment 7 shows edits made to Table 9-2.
Comment:
16. Page 9-5. Paragraph 1 • Discuss the concentration which was developed for protection of acute effects resulting from exposure to PCDD/PCDF. This discussion should include the toxicity value used to develop the protective concentration level.
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DRAFT
Response:
Section 9.1.1.2, Degradation of Constituents, has been removed from the text. Therefore, the evaluation of potential acute effects has also been removed.
Comment:
17, Page 9-6. Section 9.2, Paragraph 4 • The last complete sentence In this paragraph should Indicate that the cleanup levels referred to are for the protection of groundwater.
Response:
This statement has been added and can be reviewed in Attachment 6.
Comment:
18. Page 9-7, Paragraph 3 • A discussion of PCDD/PCDF In subsurface soils should be Included In this paragraph.
Response:
The text has been edited and can be reviewed in Attachment 6.
Comment:
19. Page 9-8, Paragraph 3 • It appears that the document preparers have decided that the appropriate soil RBTCL remediation risk level should not be 10-5• This decision concerning the appropriate remediation risk levels will be made by the Agency.
Response:
The summary of potential remedial options presented on Table 9-2 in the Baseline Risk Assessment report (and repeated in Table G-11 in Appendix G), was designed to reduce the volumes of information presented in Appendix G, and not to imply that a decision had been made regarding the risk level for selection of remedial goals. Based on the most likely future Site use, however, Beazer feels that appropriate remedial goals for this Site would be set at the 1 E-05 risk level for commercial/industrial site use.
In response to this comment, however, Table 9-2 and Table G-11 have been edited to include RBTCLs at the 1 E-04 and 1 E-06 risk levels as requested by EPA. The edits to these tables are shown in Attachments 7 and 12. Please note that Table 9-2 has been re-numbered in this revision as Table 9-1 and Table G-11 has been re-numbered as Table G-8.
Comment:
20. Page 9-8, Paragraph 5 • There Is not enough PCDD/PCDF data to make the statement that remediation of PCP will also satisfactorily remediate for PCDD/PCDF.
Response:
Since, the available pentachlorophenol and dioxin data for Area C soils supports this statement, the text in this Section has been edited to acknowledge that this conclusion is based on 'available" data. An additional statement has been added to the text in this Section that acknowledges the need for additional sampling during the Remedial Design activities to confirm this remediation strategy. These edits are shown in Attachment 6.
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Comment:
21. Page 9-12. Table 9-2 -This table should Include PCDD/PCDF data for subsurface soil.
Response:
The data for dioxin in subsurface soil was not included in this summary table in the last draft because the table was designed to reduce the volumes of information presented in Appendix G. The last draft of the table included human health RBTCLs for the 1 E-5 risk level only. Because the maximum concentration of dioxin in subsurface soil (0.004 ppm) did not exceed the RBTCL derived at the 1 E-5 risk level for any of the receptors or the soil target level for the protection of ground water, this medium was not identified for potential remediation for dioxin.
Although we still stand behind our preference to present RBTCLs derived at the 1 E-5 risk level in the summary tables, we have edited this table (and the summary table in Appendix G) as requested in this comment. These edits are shown in Attachments 7 and 12.
Comment:
22. Section 7.1.2.2. Paragraph 2 -The conclusory statement that "current study criteria are almost certain to lead to substantial overestimation of potential assumed cancer risks in Humans" should be changed to read: " ... current study criteria may lead to overestimation of .•. ".
Response:
The text has been edited as requested and can be reviewed in Attachment 5.
Comment:
23. Section 9.2 -There Is an Inadequate discussion of ARARs. and ARAR based cleanup requirements. At the least. some discussion of the North Carolina MCL for 2-chlorophenol. and a calculation of derived remedial levels must be Included, as this Is an applicable and relevant standard.
Response:
Response pending.
APPENDIX G COMMENTS -
Many of the responses reported below are shown in Attachment 10.
Comment:
1. General Comment -Previous comments on degradation, average versus maximum concentration, remediation risk level and subchronic remediation levels also apply to this appendix.
Response:
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The text of Appendix G has been edited as requested and is shown in Attachment 10.
Comment:
2. Page G-9. Paragraph 3 -The "pick-up level" concept only applies If the average concentration is used for remediation. Therefore, this is not applicable to the Koppers RBTCLs.
Response:
The comment does not correctly describe the pick-up level concept. The concept applies to any concentration of constituents being used for remediation. An RBTCL can be compared to the arithmetic mean, geometric mean, or any other upper-bound concentration (i.e. 951" confidence interval on the mean, maximum concentration, etc.) in order to derive a 'pick-up level' that is protective at the individual risk level assumed by the RBTCL. The pick-up level in each of these cases would assume that the target constituent concentration (e.g. arithmetic mean, geometric mean, 951" confidence interval, the maximum, etc.) were equal to or less than the RBTCL.
Although we still believe that concept of averaging represents a more scientifically appropriate approach to evaluating a Site and the derivation of and application of remedial goals, we disagree with the comparison of RBTCLs with maximum concentrations. We, however, will remove this concept (the 'pick-up level' concept) from the report as requested by EPA.
Comment:
3. Page G-18, Paragraph 1 -Class II groundwater must be remediated to residential consumption protection levels regardless of site use.
Response:
The text has been edited to show that remediation of ground water may be required based on ARARs and other standards even it if it is not indicated based on assumed risk.
Comment:
4. Page G-24, Paragraph 4 -The statement that all sediment concentrations were below RBTCLs is not true for the 1 o,.; level of risk for residential exposure to the Fire Pond sediment for the RME and maximum concentration levels.
Response:
We acknowledge that potential assumed sediment risks may exceed the 1 E-06 risk level, however, remediation to this level is considered inappropriate by Beazer East, Inc. given that the Site will most likely remain commercial/industrial in the future.
However, in response to this comment, a new sub-section has been added to the text discussing the comparison of sediment concentrations with RBTCLs.
Comment:
5. Page G-26. Paragraph 2 -The lowest RBTCL for PCDD/PCDF in surface soil is 1E-5 (1 o,.; risk level), not 1 E-4 as stated in the text.
Response:
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The text has been edited to show the lowest RBTCL for dioxin. The RBTCLs shown on the revised summary tables are RBTCLs derived assuming no degradation occurs; the lowest RBTCL for dioxin now shown on the summary tables, and in the text, is SE-6 ppm.
Comment:
s. Page G-27. Section G.4.3 • The offsite groundwater RBTCLs should be based on the future residential consumption of groundwater.
Response:
The off-Site ground water RBTCLs are based on the future off-Site resident's assumed exposure to off-Site ground water as drinking water. The text has been edited to clarify this.
Comment:
7. Page G-27, Section G.4.3.1. Paragraph 2 • The MCL for TCDD has not been promulgated. It is proposed at this time and should be identified as a proposed MCL
Response:
The tables and text of Appendix G and Section 9 have been edited to show that the MCL for TCDD is a proposed MCL.
Comment:
8. Page G-29. Section G.5.1 -The sediment from Fire Pond should be identified as a media possible requiring remediation.
Response:
New text has been added that explicitly identifies any maximum constituent concentration that exceeds RBTCLs derived in Tables G-2a, G-3a, G-4a and G-Sa (RBTCLs assuming that no degradation occurs). The specific request to identify sediment as a medium possibly requiring remediation is included in this new text. It is important to note, however, that sediment may only require remediation if the remedial goal at this Site is set at the 1 E-06 risk level. Sediment in the Fire Pond Discharge Stream may require remediation only at the 1 E-06 risk level assuming the future commercial/industrial Site use scenario. Sediment in Fire Pond may require remediation only at the 1 E-06 risk level assuming the future residential Site use scenario.
Comment:
9. Pages G-30 and G-31. Section G.5.2 • As previous comments indicate, the Agency Is not in agreement with several of the assumptions used to develop and interpret the RBTCLs. The risk management decision made in this section will be made by the Agency. This section must be deleted.
Response:
This Section has been deleted.
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COMMENTS FROM THE STATE OF NORTH CAROLINA DEHNR
Comments from Bruce Nicholson. April 20. 1992
Comment:
1. Page 4-11. Section 4.3.2 -Inhalation factors are based on PM,0 concentrations from monitoring stations in Raleigh and Durham. However, the Koppers site Is still active and there are dirt roads and unvegetated cleared areas on the site. Therefore, fugitive emissions from wind blown dusts and road traffic could make local particulate levels much higher than at the ambient monitoring stations. Therefore, the Superfund Section would like to see an analysis of fugitive dust emissions from wind and road travel to compare with the PM10 approach. Fugitive emission estimates should be generated by following EPA's protocol set forth In the Compilation of Air Pollutant Emission Factors, EPA Publication No. AP-42.
Response:
To respond to this comment, it is necessary to clarify the layout of the Site. We acknowledge that a small portion of the Beazer Site consists of a dirt road and some areas with little vegetation. We also acknowledge that the Unit Structures area of the Site is still active. However, it is important to note that the dirt road and bare areas on the Beazer Site are located in the inactive section and are not used. Traffic on the dirt road is very infrequent. Therefore, a fugitive dust emissions analysis is unnecessary for the Beazer Site.
We submit that the PM,0 value that was supplied by North Carolina's Department of Natural Resources and used in the Baseline Risk Assessment is more than sufficient and does not require additional analysis. The text edits can be seen in Attachment 17.
Comment:
2. Pages G-20 and G-22 -On Page G-20 the Risk Assessment states that the hazard quotient for the muskrat Is 0.1 which Is In the range of "posslble concern". On Page G-22, concerning the muskrat evaluation, it states that because the estimated exposure to all constituents results In a hazard quotient considered to be of "no concern", no RBTCL's were calculated for the muskrat. These two statements are inconsistent; please revise.
Response:
The total potential assumed hazard quotient for the muskrat was estimated to be 0.1 which is at the very bottom of EPA's range of 'possible concern' (0.1 to 10.0). As reported on page G-22 of the Baseline Risk Assessment, because the total assumed hazard quotient is equal to 0.1, each constituent-specific hazard quotient is less than 0.1, or of 'no concern'. The text has been edited on page G-22 to clarify this classification.
Comments from Kenneth Rudo. April 16, 1992
Comment:
1. The Environmental Epidemiology Section (EES) recommends that the use of average constituent concentrations for determining remediation levels not be utilized. If any
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specific areas exceed the cleanup goal, then there Is a need tor remediation and basing it on maximum levels should improve overall health protection at this site In the future.
Response:
As discussed in previous comments, even though Beazer strongly disagrees with the EPA-recommended approach and supports the comparison to average concentrations, maximum constituent concentrations have been used in the revised report in discussions concerning the recommendation of remediation levels.
Comment:
2. EES recommends that risk values for carcinogens be based on 10..i risk values not 10 .. or 10·5 levels which are the suggested values In the risk document.
Response:
As requested by EPA in earlier sets of comments, RBTCLs were derived for three separate risk levels, 1 E-04, 1 E-05 and 1 E-06. In the last draft of the Baseline Risk Assessment report, comparisons of RBTCLs at the 1 E-05 risk level were presented because this is the risk level thought to be most representative of this type of Superfund site. In response to a request by EPA, RBTCLs at the 1 E-04, 1 E-05, and 1 E-06 risk levels will be presented in the revised report.
As reported by EPA in their Comment #19 (June 4, 1992), '(the) decision concerning the appropriate remediation risk levels will be made by the (federal) Agency'.
Comment:
3. The proposed PCP soil cleanup value recommended in the document is well above a safe level needed to adequately protect human health. The use of a degradation factor for PCP appears to be, for the most part, simply a mechanism for a less stringent soil remediation level. The approach used to derive the proposed and revised degradation factors appear to be vague, Jacking concise site-specific data necessary to utilize degradation as an assumptive factor in a risk assessment. EES strongly recommends that degradation rates not be utilized in the derivation of RBTCLs for PCP at this site.
Response:
As discussed in previous comments, even though it is clear to Beazer that the scientific literature indicates that degradation occurs, the concept of degradation has been removed from the main text of the report. The potential impact of degradation on the results of the report are compared in the Appendix to the report with the results estimated assuming no degradation occurs. Beazer disagrees that the use of degradation in the calculation of RBTCLs is 'a mechanism for a less stringent soil remediation level'. U.S. EPA Risk Assessment Guidance recommends that degradation be assumed in the evaluation of a site. In addition, based on scientific, repeatedly documented studies, degradation does occur in the ambient environment. However, at the request of U.S. EPA Region IV, and as discussed in previous comments, the application of degradation has been removed from the main text of the Baseline Risk Assessment.
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ATTACHMENTS
1 May 5, 1992 letter from Shannon Craig at Beazer, to Barbara Benoy at EPA Region IV.
2 Revised pages for Section 2.
3 Revised text for Section 5.
4 Example of Revised Section 5 Tables.
5 Revised text for Section 7.
6 Revised text for Section 9.
7 Revised Table 9-2 (re-numbered as Table 9-1).
8 New text for Appendix E.
9 Scaling tables removing degradation from exposure spreadsheets in Appendix E-4.
10 Text edits for Appendix G.
11 New Appendix G tables (G-2a, G-3a, G-4a, and G-5a).
12 Revised Table G-11 (re-numbered as Table G-8).
13 Revision to Table E-2; Table E-3 (formerly Table 5-19); and Table G-1 (formerly Table 9-1).
14 Revised Table 2-12 (specific comment #3).
15 Revised text for Appendix C-3 (specific comment #4).
16 Revised reference in Table 4-6 (specific comment #5).
17 Text edits for PM10 discussion (State (Bruce Nicholson) comments #1).
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Comment:
DRAFT
COMMENTS FROM U.S. FISH AND WILDLIFE SERVICE
APRIL 10, 1992
1. The ecological risk assessment for the belted kingfisher, particularly Section 6.5.1.2
(Avian Dose-Response Values), should be revised after review of available
toxicological literature concerning sensitive avian species and sensitive endpoints.
Until such revisions are complete, statements such as " ... conservative assumptions
applied in the mammalian and avian evaluations are likely to result in an overes-
timate of the potential for adverse effect .... " (page 7-1 o of the Draft BRA) are
Inappropriate.
Response:
Please see response to Comment 5.
Comment:
2. Fish tissue and sediment dioxin and furan residues should be further evaluated. The
Draft BRA should expand the discussion on significance of sediment contamination
(Section 6.4.2, Exposure Evaluation), particularly the extent to which contaminated
sediments Influence water and fish tissue dioxin concentrations. Such an evaluation
and discussion will help provide a rationale, other than that based on human health
concerns, for the appropriate course of remediation, if necessary.
Response:
Sediment concentrations affect water and fish tissue concentrations by contributing to the overall
concentrations of PCDDs and PCDFs in both water and tissue. Fish tissue residues represent
the sum of the contributions of concentrations of chemicals in water, food, and sediments.
Therefore, by using fish tissue residues to evaluate the potential for adverse effect to the belted
kingfisher, the contribution of sediments was implicitly assumed. In order to evaluate potential
toxicity to aquatic organisms, comparisons were made to screening values from Region IV or
to Ambient Water Quality Criteria, where available. No values have been developed for
evaluating sediment concentrations of constituents.
Comment:
3. Sediment and surface water bloassays are recommended.
Response:
Given the results of the ecological risk assessment and the conservative assumptions upon
which it is based, it is not anticipated that sediment and surface water bioassays, using the biota
living or expected to be living on the site, would produce results of concern or different from that
reached in the existing analysis. Consequently, it is unlikely that the results of a bioassay would
alter the conclusions reached by the current aquatic ecological risk assessment.
Comment:
4. There is a lack of data for dioxins and furans In the western drainage ditch and
associated wetlands.
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DRAFT Response:
Surface water in the western drainage ditch was sampled for dioxins (Table 2-7) and TCDD-TE were reported for one sample at 4.2E-05 µg/1. TCDD-TE samples from Fire Pond ranged from 1.2E-04 µg/I to 2.85E-04 µg/I with a mean of 1.65 µg/I (Table 2-6). Similarly, surface sediments in the western drainage ditch were sampled for dioxins (Table 2-9) and TCDD-TE were reported for one sample at 0.17 µg/kg. TCDD-TE samples from Fire Pond ranged from 0.04 µg/kg to 0.49 µg/kg with a mean of 0.21 µg/kg (Table 2-6). The choice of indicator species and site data was made with the underlying assumption that the potentially most highly exposed receptor should be investigated to ensure that the analysis would be protective of species occurring at other areas of the site. Thus, the ecological risk assessment's use of constituent concentrations from Fire Pond results in a more conservative analysis than if data from other areas of the site had been included.
Comment:
COMMENTS FROM U.S. FISH AND WILDLIFE SERVICE
MARCH 12, 1992
5. The Service believes values and assumptions In the Draft PHEA's risk assessment for the belted kingfisher are not adequately supported. As a particular example, Section 6.5.1.2 (Avian Dose-Response Values) cites only one study to support a 1,000 pg dioxin/ g egg No Observed Adverse Effects Level (NOAEL) used as the basis for the model. Verrett (1970; as cited in Kubiak et al., 1989) reported that 10 to 20 pg / g of 2,3,7,8-tetrachlorodibenzo-p-dioxin In chicken eggs produced embryotoxicity, edema, and deformities. Dose-related Increases in cardiovascular malformations of chick embryos were reported by Cheung et al. (1981; as cited in Kubiak et al., 1989), observing a 20 percent increase in malformations at a dosing level of 6 pg / g and a doubling of malformations at 65 pg / g. While the studies cited here are by no means an exhaustive review of the literature, they indicate that an avian NOAEL for dioxins of 1,000 pg / g Is potentially in error by two to three orders of magnitude.
Response:
The research that was presented in the ecological risk assessment as ENSR (1989) has also been reported in the 1988 proceedings of the TAPPI conference and will also be cited as such (Thiel et al., 1988). Two approaches will be followed to provide additional support. These include the evaluation of dietary levels and the incorporation of additional information from the report by Kubiak et al. (1989) into the determination of an appropriate benchmark concentration !cir the belted kingfisher.
Data cited in Eisler (1986) indicate that 'diets containing up to 10 or 12 ppt of 2,3,7,8-TCDD may prove to be non-hazardous to birds and other wildlife as judged by the results of laboratory studies with rats, monkeys, and chickens, and by the recommendation of New York State for human health protection.' The average concentration of TCDD-TE in the fish fillets sampled from Fire Pond was 18 ppt. Making the very conservative and unrealistic assumption that the belted kingfisher consumed its entire diet from Fire Pond would result in a dietary level only slightly above the level considered "non-hazardous·. Making the far more realistic assumption that only a portion of a kingfisher's food comes from Fire Pond and most comes from other
546626. WRA., 0845--0()8.51 0 June 22. 1992
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sources (please see response to Comment 6) would result in an average dietary intake below this level.
The Kubiak study reported a level of 201 pg TCDD-TE/g egg in tern eggs from the control site at Lake Poygan in Michigan and a level of 2175 pg TCDD-TE/g egg in tern eggs from the test site at Green Bay in Michigan. Both levels are considerably higher than Cheung et al. (1981) who reported cardiovascular malformations 'at a dosing level of 6 pg/g' for domestic chick embryos. Other effects reported included subcutaneous edema, crossed beaks, and stunted, malformed legs. Kubiak et al. also report on unpublished data from Verret that ·as little as 10 to 20 pg/g of 2,3,7,8-TCDD in chicken eggs produced embryotoxicity, edema, and deformities." Additional unpublished data from Verret was used to develop an LD50 for chicken embryo of 140 pg/g. Kubiak et al. then report that these and other symptoms are similar to the results reported for the Green Bay site {2175 pg TCDD-TE/g egg) in their research but not observed at the control site at Lake Poygan. No discussion was presented by Kubiak et al. as to why domestic fowl appear to be more sensitive than wild tern populations sampled in this report. Eisler (1986) noted that domestic chickens were relatively sensitive to dioxin, and this observation supports the hypotheseis that domestic fowl may not represent conditions that are found in wild populations.
The results reported by Thiel et al. (1988) involved both laboratory and field studies. The laboratory studies also looked for effects similar to those reported by Verret and Cheung et al., as cited in Kubiak et al.(1989). That is, the researchers specifically looked for evidence of subcutaneous edema and ascites formation. These are two of the effects identified by Kubiak et al.(1989). No subcutaneous edema or ascites formation was detected in the controls or any of the treatment groups less than, or equal to, 1,000 pg TCDD/g egg. If responses are seen at the levels reported in the articles cited in Kubiak et al.(1989), then severe reductions in hatching and fledging success should have been observed both in the Thiel et al. (1988) report and at the control site of the Kubiak et al. (1989) study. However, no reductions in survival or other effects were observed when compared to controls.
Both Thiel et al. (1988) and Kubiak et al. (1989) can be used to estimate no effect levels that are considerably higher (1,000 and 200 pg TCDD-TE/g egg, respectively) than those cited reports in the Kubiak et al. (1989) study. Kubiak et al. (1989) note that the effects observed by Verret and by Cheung et al. were observed at the Green Bay site, but not at the control site at Lake Poygan. Using the no effect level of Thiel et al. (1988) of 1,000 pg TCDD-TE/g egg resulted in a calculated potential noncarcinogenic quotient of0.12 for the belted kingfisher. Use of the more conservative field results of Kubiak et al. (1989) indicating a no effect level of 200 pg TCDD-TE/g egg would result in a calculated potential noncarcinogenic quotient of 0.60 for the belted kingfisher.
Even though the most appropriate interpretation of the above discussed scientific data would not make this change for the Raleigh site, but would instead retain the assumptions currently used by the ecological risk assessment, the change to a NOAEL of 200 pg TCDD-TE/g egg will be made. Because the 200 pg/g NOAEL and those derived from sites in Green Bay include substantial amounts of non-dioxin compounds such as PCBs, they are not applicable to this site. The TEF scheme used to convert PCBs to TCDD-TEs is still highly speculative, especially for ecological receptors. The differences between NOAELs derived based upon the Green Bay site (high in PCB's), Lake Poygan (lower in PCBs) and Thiel's studies (no PCBs) strongly suggest
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DRAFT that PCBs may be determining the NOAELs for TCDD-TEs in wildlife. Because PCBs are not a constituent of concern at this site, and given the limitation of available TEF schemes, use of a NOAEL derived from exposure to PCBs is expected, as stated above, to overpredict any potential risk for wildlife associated with exposure to TCDD-TEs at this site. The change to such a NOAEL has been made anyway.
Comment:
6. The revised assessment should fully investigate the toxicological literature available concerning sensitive avian species and effects, provide additional rationale for assumptions in the model (e.g., use of average fish dioxin concentrations to represent dietary exposure, and use of one-half as the percentage of forage obtained from the Fire Pond), and address confidence in the selected parameters. The extent to which assumptions and uncertainty in the parameters effect model output should also be discussed.
Response:
Distribution of fish tissue concentrations in Fire Pond is a function of feeding behavior and movement. No evidence was obtained to indicate that belted kingfisher feeding preferences were associated with specific areas of Fire Pond, nor are such preferences expected given the relatively small size of the pond. Because of the small size of the pond all fish tissue concentrations were assumed to be distributed uniformly. Thus the mean tissue concentration was used with the assumption that at any given time, the probability of a higher or lower fish tissue concentration would be equally likely.
Sayler and Lagler (1946; as cited in DeGraaf and Rudis, 1986) report that two pairs of belted kingfishers on two lakes used 0.5 miles of shoreline for their home range. The area of the Fire Pond is approximately four acres. Assuming that Fire Pond can be represented as a circle, the shoreline was calculated to be approximately 0.28 miles. This would represent one half of the distance reported above for the home range and indicates that belted kingfishers would spend part of their lives foraging in other areas.
Comment:
7. Similarly, the results of fish tissue and sediment dioxin and furan residues should be evaluated in relation to available ecotoxicology literature. Data on adverse effects levels of dioxins and furans in prey of piscivorous migratory birds should be used to evaluate the risk to these organisms at the site (i.e., compare dietary levels of dioxin shown to impair piscivorous predators to the concentrations measured in fish from local ponds). This type of analysis and discussion would augment the risk assessment model for avian impacts.
Response:
Please see response to Comment 5.
Comment:
a_ A more comprehensive risk assessment should result in a defensible charac-terization of the potential risks from dioxin and furan contamination. There is, however, the mixture of phenolic compounds for which pertinent toxicity data may not be available. Therefore, the Service reiterates the need for sediment and surface
546626.WRA, 0845-008-510 June 22, 1992
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water bioassays previously recommended In the Department's October 20, 1989, Preliminary Natural Resources Survey (copy attached).
Response:
Please see responses to Comments 2 and 3.
Comment:
9. Our review of available analytical chemistry data for the site revealed a lack of sampling for dioxins and furans in palustrine forested wetlands in the southwestern corner of the site. Concern for this area also was expressed In the Department's 1989 Preliminary Natural Resources Survey. Samples from this location analyzed for pentachlorophenol showed presence of site-related contaminants; thus, the entire suite of site-related contaminants should be evaluated at this location.
Response:
Samples from the southwestern corner of the site were analyzed for pentachlorophenol and total acid extractable phenolics. Summary results are presented in Figure 2-5. Examination of this figure indicates that pentachlorophenol was not detected in any of the samples. Total acid extractable phenolic concentrations were within the range of background concentrations (presented in Figure 2-6) and considerably lower than total acid extractable phenolic concentrations in soils in the area surrounding Fire Pond (Figure 2-4). Indicator species were chosen to represent potentially highly exposed populations. Therefore, the belted kingfisher and muskrat were chosen to be evaluated using the concentration data from Fire Pond. Selection of an indicator species from the palustrine forested wetlands would have resulted in a less highly exposed receptor.
Comment:
COMMENTS FROM U.S. FISH AND WILDLIFE SERVICE
JUNE 2, 1992 ATTACHMENT DATED OCTOBER 20, 1989
1 o. Migratory birds, trust resources of this Department, are present on the site and adjacent to It. There are no national parks, wildlife refuges, or Indian reservations In the vicinity. Two endangered species, bald eagle and red-cockaded woodpecker, and one proposed endangered plant species, Michaux' poison-sumac, are listed for Wake County. five species In Wake County are under review for endangered species status. These are Bachman's sparrow, Carolina madtom, Lewis' heartleaf, Nestronia, and Carolina trillium.
Response:
The Fish and Wildlife Service, Raleigh Field Office, provided "Federally listed endangered (E) and/or threatened (T) and/or candidate species(C) which may occur in the area of influence of this action"(Gantt, 1992). These resources, as well as other resources identified by the State of North Carolina DEM, were evaluated in Appendix F-4 of the latest version of the ecological risk assessment.
Comment:
546626.WP.A. 0845-008-510 June 22. 1992
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11.
DRAFT
We have determined that contamination has occurred in the past and a high potential for continuing and future contamination exists. The presence of PCP contamination In the surface water and sediments Is an ongoing threat to the fish and wildlife that use the area. The continued release of PCP and other contaminants via ground water discharge into local streams and ponds represents a long-term threat to fish and wildlife resources.
Response:
Pentachlorophenol, where detected, was evaluated in the ecological risk assessment. Surface water concentrations of pentachlorophenol were below acute and chronic AWOC values. Pentachlorophenol contributed less than 5 percent of the total hazard index calculated for the muskrat. Because pentachlorophenol is not predicted to bioaccumulate (BAF of 780.1) (GLWQI, 1992), it is not unanticipated that it was not detected in fish samples from Fire Pond or Medlin Pond.
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REFERENCES
DeGraaf, Richard M. and Deborah D. Rudis. 1986. New England Wildlife: Habitat, Natural History, and Distribution. Gen. Tech. Rep. NE-108. Broomall, PA: U.S. Dept. Agric. Forest Service.
Eisler, R. 1986. Dioxin Hazards to Fish, Wildlife, and Invertebrates: A Synoptic Review. Biological Report 85 (1.8) U.S. Fish and Wildlife Service. Laurel, MD.
Gantt, L.K.Mike. 1992. Letter dated December 18, 1991 received by D. Pinnas, ENSR, from L.K.M. Gantt, U.S. Fish and Wildlife Service, Raleigh Field Office.
GLWQI. 1992. Great Lakes Water Quality Initiative (GLWQI). Summary of Proposed Human Health BAFs for the GU. Draft 9-23-91. U.S. EPA Region V.
Kubiak, T.J., H.J. Harris, L.M. Smith, T.R. Schwartz, D.L. Stalling, J.A. Trick, L. Sileo, D.E. Docherty, and T.C. Erdmen. Microcontaminants and Reproductive Impairment of the Forster's Tern on Green Bay, Lake Michigan-1993. Arch. Environ. Contam. Toxicol. 18:706-727.
Thiel, D.A., S.G.Martin, J.W. Duncan, M.J. Lemke, W.R. Lance, and R.E. Peterson. Evaluation of the Effects of Dioxin-Contaminated Sludges on Wild Birds. Proceedings of the 1988 Environmental Conference. TAPPI.
546626.WP.A. 0845-006·510 June 22, 1992
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BL\ZER EAST. 1;-s;e,, 436 SEVE"°'TH -\VE\!UE. PITTSBURGH. P-\ 15219 US.-\
FEDERAL EXPRESS
Dear Ms. Benoy:
May 5, 1992
Ms. Barbara Benoy
U. s. Environmental
Protection Agency
Region IV
345 Courtland Street, N.E.
Atlanta, GA 30308
RE: Baseline Risk Assessment for the
former Koppers Company, Inc. Site
in Morrisville, North Carolina
Pursuant to our conversation earlier this week, this letter acknowledges our
agreement to revise the Baseline Risk Assessment to remove the assumption of
degradation from the body of the report. As we discussed, we will include a
discussion of the potential impact of degradation of the assumed risks and
clean-up levels estimated for the Site in the Uncertainty Section (Section
7.0) and in the Appendix to the report.
Your initial request to remove all references to degradation of pentachloro-
phenol from the body of the Baseline Risk Assessment came to us in a letter
dated March 30, 1992. As you are aware, we submitted the second draft of the
body of the Baseline Risk Assessment report (plus Appendices) to EPA on March
19, 1992. The revised clean-up levels evaluation was submitted to EPA on
March 31, 1992 as Section 9 and Appendix G to the Baseline Risk Assessment.
Notification to remove degradation from the reports was received too late for
the incorporation into either submittal.
The issue of degradation was also discussed with you, additional EPA
representatives, and representatives from the State, at our meeting on March
4, 1992. No decision regarding use of degradation was reached at that
meeting. At the March 4, 1992 meeting, it was agreed that ENSR would submit
a table in the March 19, 1992 submittal showing the estimated risks
associated with potential exposure to Area C surface soils assuming degraded
concentrations of pentachlorophenol and dioxin as well as estimated risks
assuming non-degraded concentrations. ENSR submitted a table as part of the
body of the revised Baseline Risk Assessment (Table 5-19) that compared
assumed risks from exposure to pentachlorophenol and dioxin for all relevant
media assuming degraded and non-degraded concentrations of these constitu-
ents. We also agreed at the March 4, 1992 meeting that ENSR would reevaluate
the degradation rates used for pentachlorophenol and submit the results of
this reevaluation in the March 31, 1992 submittal. Upon review of additional
literature materials, ENSR edited the clean-up levels Sections to the
Baseline Risk Assessment report to reflect a more conservative degradation
rate for pentachlorophenol in various media.
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Ms. Barbara Benoy
May 5, 1992
Page 2
Although we stand by our position that the use of degradation rates is
scientifically appropriate and defensible, and supported by EPA guidance, we
will honor your request to remove degradation from the body of the Baseline
Risk Assessment report. We would, however, like the opportunity to confirm
the degradation of pentachlorophenol during the Remedial Design, should we so
choose. In your letter dated March 30, 1992, you state that 'if degradation
is allowed in a risk assessment document, it should be based on site-specific
data ... ( and) ... actual field observation/confirmation must be presented".
Thus, we request acknowledgement in the ROD that, if degradation rates are
confirmed during the Remedial Design, clean-up levels will be modified as
appropriate.
If you are in agreement with this request to conduct confirmational studies
on the degradation of pentachlorophenol during the Remedial Design, we will
prepare a Workplan to perform these activities. Upon EPA approval of this
proposed Workplan, we will commence the degradation study.
We also request that all additional comments on the second draft of the
Baseline Risk Assessment report be forwarded to us as soon as possible so
that, as we revised the report to remove degradation, we can address any
additional comments at the same time. Early notification of additional
comments will help facilitate our resubmittal of the draft Baseline Risk
Assessment to the agency.
SKC/dkm
cc: W. Giarla, BEI
J.,. Mitsak, KER
.,.s. Allen, ENSR
C. Fehn, EPA
C. Winokur, EPA
E. Aiken, EPA
B. Fox, EPA
P. DeRosa, NCDEHNR
L. Crosby, NCDEHNR
R. Kraska, Dynamac
Sincerely,
-,/)IL.~,'-''--""'"? .-;:(· (,~ '-<--r' .' !i
Shannon K. Craig
Program Manager -Environmental Group
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2.0 HAZARD IDENTIFICATION
The purpose of hazard identification is to identify and characterize Site-related compounds, and
select a subset of constituents that will be used in the remainder of the baseline risk assessment
to estimate potential health and environmental assumed risks. The subset of compounds, called
the constituents of interest, is selected from all compounds analyzed at the Site. EPA risk
assessment guidance (U.S. EPA, 1989d) describes a process for selecting the constituents of
interest at a site. This selection involves evaluating several factors, including potential toxicity,
prevalence, environmental mobility and persistence of constituents detected at and near the Site.
The preliminary identification and selection of constituents was performed by Keystone and is
described in the Work Plan to Perform a Remedial Investigation and Feasibility Study (RI/FS) at
the Morrisville, NC Site, henceforth referred to as the RI/FS Work Plan (Keystone, 1989). The
RI/FS Work Plan reviews the potential toxicity, mobility, and persistence of the constituents. The
RI report (Keystone, 1992) reviews the prevalence of constituents at the Site. Based on these
analyses, and the hazard identification analysis presented in Appendix A-1, the preliminary list
of constituents identified in the EPA-approved RI/FS Work Plan forms the basis of the hazard
identification step completed by ENSR. The final selection of constituents of interest was based
on the "hazard identification· process described in EPA risk assessment guidance (U.S. EPA,
1989d). The results of this analysis confirmed the selection of constituents at the Site. This
process is summarized in this Section and is described in detail in Appendix A-1.
Section 2.1 reviews the sampling strategy from the RI which forms the basis of the baseline risk
assessment evaluation. Section 2.2 describes the steps used to select the constituents of
interest at the Site. Section 2.3 reviews the steps used to reduce the sampling data for the
quantitative exposure assessment. Section 2.4 compares on-Site constituent concentrations to
off-Site constituent concentrations. SectioR 2.§ discusses the poteRtial impact of degradatioR
of CORStitueRIS iR the em•iroRFReAt.
2.1 Overview of Site Sampling and Analytical Results
The following environmental media were sampled at the Morrisville Site before the specific
sampling for the RI report began: surface soil, subsurface soil, ground water, surface water,
sediment, and fish. For a complete characterization of these data and potential routes of
migration to other media and receptors, refer to Section 3.0 of tl;le RI/FS Work Plan and Section
2.0 of the RI.
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The additional comprehensive sampling performed in 1990 and 1991 as part of the RI forms the basis of this baseline risk assessment. Round 1 (from May to mid-July 1990) and Round 2 (October and November 1990) include data for surface and subsurface soil, surface water, sediment, and ground water. In addition, fish tissue samples collected in December 1990 were also included in this baseline risk assessment. Rounds 1 and 2 sampling and analyses were performed in accordance with the U.S. EPA approved RI/FS Work Plan (Keystone, 1989). At the request of EPA, additional sampling of surface soil (the Phase Ill sampling program) and ground water (the confirmational sampling program) was conducted in October, 1991, and January, 1992, respectively. Phase Ill soil sampling and analyses were performed following a scope of work approved by U.S. EPA by letter dated October 10, 1991. Confirmational ground water sampling and analyses were also performed following a protocol approved by U.S. EPA by letter dated December 10, 1991. (See Appendix A of the RI report for copies of these letters.)
All sampling and analyses were performed with EPA approved methods. Round 1 analyses included TCL CLP semi-volatile and volatile organic compounds, and pesticides/PCBs; TAL CLP metals; non-CLP phenolics, pentachlorophenol, isopropyl ether (IPE); and dioxins/furans. Round 2 analyses included non-CLP phenolics, pentachlorophenol, and IPE, and dioxins/furans. The Phase Ill soil sampling and the confirmational ground water sampling programs included analyses for non-CLP phenolics and pentachlorophenol. All sampling data are presented in Section 4.0 and Appendix F of the RI report (Keystone, 1992).
Surface soil, subsurface soil and sediment samples were analyzed for non-CLP phenolic compounds using the 8040 method, for IPE using the 8020 method, and for dioxins/furans using method 8290. Ground water and surface water samples were also analyzed for non-CLP phenolics in Rounds 1 and 2 using the 8040 method. Ground water was analyzed for non-CLP phenolics in the confirmational ground water sampling program using the 8270 method. Ground water and surface water samples were analyzed for IPE using the 8020 method, and for dioxins/furans using method 8290. In addition, EPA Method GC515, with a detection limit of 0.01 ug/1, was used to analyze specifically for pentachlorophenol in ground water and surface . water. Because of the higher sensitivity of EPA Method GCS 15, only these data were used for pentachlorophenol in the baseline risk assessment when available. Some of the Round 1 and 2 Method 8040 non-CLP phenolics data were questioned by EPA because of the potential presence of false positives. The samples in question were re-sampled in the confirmational sampling round. The method 8270 data from the confirmational sampling program are used in place of the method 8040 data from Rounds 1 and 2, when available. All samples from Rounds 1 and 2 not re-sampled in the confirmational sampling round were used in the baseline risk assessment. Fish samples were analyzed for pentachlorophenol and pentachloroanisole using method 8270, and for dioxins/furans using method 8290. Table 2-1 summarizes the sampling locations for each medium and area of interest at the Morrisville Site.
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Surface and subsurface soils were sampled in four on-Site areas, Area A: the former land farm
area, Area B: the former teepee burner area and eastern area, Area C: the former lagoon and
Cellon treatment area, and Area D: the Unit Structures active facility. Additional samples were
taken in off-Site locations. The soil sample locations are shown for all areas in Figures 2-1
through 2-6. Surface soil samples were taken from the top Oto 2 feet. Subsurface soil samples
were taken at 2 to 6 feet and below 6 feet. Only surface soil (0 to 2 feet) and subsurface soil
data from the upper 2 to 6 feet were included in the baseline risk assessment because no
prolonged exposures to soil at depths greater than six feet are expected, and because
concentrations of constituents in upper subsurface soils were almost always greater than
concentrations in deep subsurface soils. Additional samples were taken for soil at off-Site
locations.
Surface water and sediment samples were taken in six locations: Fire Pond, the discharge
stream from Fire Pond, Medlin Pond, the discharge stream from Medlin Pond, and the eastern
and western ditches on the Site's property lines. All surface water data are included in the
baseline risk assessment. Surface water sampling locations are shown in Figures 2-7 and 2-8.
Upper (0 to 2 feet) and lower (2 to 4 feet) sediment samples were taken in Fire Pond and Medlin
Pond. Only upper sediment data were included in the baseline risk assessment for the two
reasons stated above, i.e., contact with surficial sediments only is expected, and constituent
concentrations were greater in the upper sediments. Sediment sampling locations are shown
in Figures 2-9 through 2-11.
Ground water samples were collected in three on-Site areas: the Eastern Area, the Western Area
and the Former Lagoon Area. The ground water data correspond to the parcelling of soil data
as follows: Areas A and B = Eastern Area ground water, Area C = Former Lagoon and Cellon
Process Area ground water, and Area D = Western Area ground water. All unfiltered on-Site
ground water data are included in the baseline risk assessment following the criteria outlined
above. Off-Site ground water was sampled in wells near the Site and in deep wells at some
distance from the Site. Some of the constituents of potential interest at the Site were detected
at very low levels in off-Site wells. These results prompted the initiation of an off-Site domestic
well sampling program in 1986, and the installation of city water lines in 1989. Although the
domestic well data are included in the RI report, they are not part of the EPA-approved scope
for the RI, therefore, these data are not included as part of the baseline risk assessment. See
Appendix I of the RI for additional information on the domestic well sampling program.
Data from off-Site monitoring wells thought to be most greatly influenced by constituents from
the Site were included in the baseline risk assessment. These wells are identified in Table 2-1;
unfiltered data from these off-Site wells were selected following the criteria outlined above.
Because one near off-Site well (C-11) is reported in the RI to be in the on-Site plume of
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constituents (Keystone, 1992), this off-Site well is evaluated as part of the Former Lagoon and
Cellon Process Areas, on-Site. Figures 2-12 through 2-16 show the ground water sampling
locations.
Fish were analyzed for pentachlorophenol, pentachloroanisole, and dioxins/furans. As shown
in Figure 2-17, fish were sampled in the on-Site Fire Pond and in two off-Site ponds, Medlin Pond
and the Control Pond. Composite samples of fish from Fire Pond were analyzed as fillets and
body remains. Composite samples of fish from Medlin Pond and Control Pond were analyzed
in the following ways: whole bodies, fillets, and body remains. Only fillet data from Fire Pond
and Medlin Pond are used in the human health assessment because fillets are the fish part
typically consumed by humans. Fillet data from Fire Pond were utilized in the ecological
assessment. Potential assumed risks to avian species were evaluated for Fire Pond because
predator species were observed during the Site visit at Fire Pond and because constituent
concentrations were higher in fish fillet data from Fire Pond.
2.2 Identification and Selection of Constituents of Interest
As previously stated, constituents were selected for the human health and ecological evaluations
from the list of all constituents analyzed at the Site. The concentrations and frequencies of
detection of all analyzed constituents were summarized to characterize the ex1ent of constituents
in various media. The analytical data for each medium of potential interest at and near the Site
were reviewed and constituents were identified for inclusion in the risk assessment based upon
their prevalence, potential toxicity, environmental mobility, and persistence. The results of this
analysis are summarized below and are tabulated in Tables 2-2 and 2-4 through 2-12 and in
Tables A-1.1 through A-1.76 in Appendix A-1. Based on the analysis described below and in
Appendix A, information from the RI/FS Workplan and RI report, as well as information regarding
past Site use, the following preliminary list of constituents or groups of constituents of potential
interest were selected for inclusion in the quantitative risk assessment:
• phenolics (including pentachlorophenol)
• PCDD/PCDFs
• isopropyl ether
The phenolics group contains the following twelve compounds:
2,3,5,6-tetrachlorophenol
2,4,6-trichlorophenol
2,4-dichlorophenol
2,4-dimethylphenol
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2-nitrophenol
4, 6-di n itro-o-cresol
4-nitrophenol
4-chloro-3-methylphenol
2-4 June, 1992
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2.4-dinitrophenol
2-chlorophenol
pentachlorophenol
phenol
PCDD /PCDFs refers to polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans.
PCDD/PCDFs are evaluated as 2,3,7,B-tetrachlorodibenzo-p-dioxin toxic equivalents (TCDD-TE),
as shown in Table 2-3.
All twelve phenolic compounds, isopropyl ether, and PCDD /PCDFs identified as constituents of potential interest were evaluated in all media (except fish) to estimate the total potential effects of potentially Site-related constituents. [This list can ee shortened lo tv,•o constituents of interest eased on the results of the easelino risl1 assessment. The two constituents of interest that will
ee evaluated as part of the ,'easieility Study lor the Site are: pentaohlorophenol (in ground water and soil), and PGDD/PGDFs !in all media evaluated at tho Site). Although these tv.•o coAslitueAts are ideAlified as the coAstitueAts of iAlerest at the Site, data aAd results for all pheAolio compouAds, isopropyl ether, aAd PGDD/PGDFs iA all media are presoAlod iA this report lo mal1e the ovaluatioA of potoAtially Sito related coAstitueAts complete.)
Based on knowledge of past Site operations, data are summarized and presented in discrete areas of potential interest to better characterize the extent of constituents in these locations. These areas of potential interest and the frequencies of detection for all constituents selected for inclusion in the quantitative risk assessment are presented in Table 2-2 for each medium and area of potential interest. As shown in Table 2-2, surface and subsurface soil data are summarized in four discrete on-Site areas and one off-Site area, which were also identified above in Section 2.1. Ground water is summarized for four discrete areas, surface water and sediments
for six discrete areas, and fish fillet data for three discrete areas.
All constituents or groups of constituents listed above were detected in subsurface soil and ground water at or near the Site. Phenolics including pentachlorophenol, and PCDD /PCDFs were detected in surface soil, sediment and surface water. lsopropyl ether was not detected in surface soil, sediment or surface water. Pentachlorophenol and pentachloroanisole were analyzed for, but not detected in fish; PCDD/PCDFs were detected in fish. Fish were not analyzed for other constituents because of the small potential for bioaccumulation of the other constituents in fish tissue.
A detailed Hazard Identification was conducted in accordance with the steps outlined in the EPA
Risk Assessment Guidance for Superfund (U.S. EPA, 1989d) on all analytical data, exclusive of those data for the compounds listed above, in order to determine whether additional constituents required inclusion in the quantitative risk assessment. For each constituent detected in each medium/area, the detected concentration of the constituent was compared to both the Sample
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Quantitation Limit for that constituent in that analysis and also to a toxicological benchmark
concentration derived for that constituent in that medium. A detailed description of the process
by which these benchmark concentrations were derived is presented in Appendix A-1. The
results of this Hazard Identification are presented in Appendix A-1 and indicate that no additional
constituents analyzed at the Site need be added to the preliminary list of constituents of potential
interest selected for evaluation in the quantitative risk assessment.
In addition to the use of toxicological screening techniques to select constituent of potential
interest in soil and ground water, the potential for leaching of constituents from soil to ground
water was considered in the selection of constituents for quantitative evaluation. The leaching
potential of constituents found in the unsaturated soils at the Beazer site was evaluated in the
RI report (Keystone, 1992). This evaluation included a consideration of the physical and
chemical properties and environmental mobility of the constituents of interest. Environmental
mobility was defined in a general sense by calculation of a 'mobility index" and in a specific
discussion of the environmental processes that are likely to be important at this Site. Following
the later analysis, it was concluded that the most significant potential route of constituent
migration is the potential leaching of constituents from soil to ground water with infiltrating
precipitation.
This phenomenon was examined using an ex1remely conservative model of constituent transport
vertically through the unsaturated zone and into the underlying bedrock ground water units. Site-
specific partitioning coefficients for pentachlorophenol and TCDD were developed. These data
were used in a transport model to determine soil concentrations (i.e., clean-up standards)
protective of ground water quality. Processes such as degradation, dispersion, volatilization, and
adsorption that would have raised the clean-up standard were not included in this model. The
clean-up standards were determined for pentachlorophenol and 2,3,7,8-TCDD. An analysis of
the potential impact of the clean-up levels in soil for the protection of ground water is presented
in Section 9.0 of this report.
2.3 Data Analysis
As previously stated, data from three rounds of sampling (May/June 1990, October/November
1990, and December 1991) form the basis of the human health evaluation. There are typically
two approaches for analyzing data from several rounds of sampling. Select sample data can be
used preferentially, the data from each round can be averaged to yield the average concentration
at each sampling location, or the data can be summed to yield total concentrations. In the
baseline risk assessment, data from each round for a particular location were not averaged;
rather, all data were treated as discrete sampling points. This is the more conservative of the
two approaches because the averaging of sampling rounds can dilute certain maximum
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concentrations. Data reduction steps performed include averaging of laboratory duplicates taken during independent rounds of sampling with the original sample result. As prescribed in EPA guidance (U.S. EPA, 1989d), one half the sample quantitation limit was used as a proxy concentration for all samples reported as "below detection limit," except for samples containing dioxin. The approach used to analyze the dioxin data is described as follows:
The toxicity of the different polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) isomers varies widely. However, much of the available research has utilized the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) isomer. While TCDD appears to be the most toxic of the isomers, its mechanism of action is likely to be similar to that of the other isomers and congeners. Therefore, it is an appropriate model for evaluating the whole class.
In this assessment, PCDD/PCDF are evaluated as 2,3,7,8-TCDD toxic equivalents (TCDD-TE). These TCDD-TE are based on structure-activity relationships and toxicological data, which are used to estimate relative toxicological properties between PCDD/PCDF and TCDD. TCDD-TE are reported as a ratio of toxicity of a PCDD/PCDF compound to the specific isomer 2,3,7,8-TCDD. These ratios are then summed to give the total TCDD-TE. The toxic equivalents used in this baseline risk assessment were provided by EPA (U.S. EPA, 1989c) and are presented in Table 2-3.
As prescribed in EPA risk assessment guidance (U.S. EPA, 1989d; U.S. EPA, 1991 b), constituent concentrations used to estimate exposure doses are the upper 95th percent {"lo) confidence limit on the arithmetic mean value of measured constituent concentrations. If the upper 95% constituent concentration exceeded the maximum detected value in a sample set, then the maximum constituent concentration was used to estimate potential health assumed risks. The use of upper 95% confidence limit concentrations is a conservative assumption because, by definition, the upper 95% confidence limit is the level at which one can be 95% confident that the actual arithmetic mean constituent concentration is lower. If there are few samples, or the variation in concentrations of constituents in a particular medium or area is large, the upper 95% confidence limit is very high, because the confidence in the database is low.
Current U.S. EPA risk assessment guidance (U.S. EPA, 1989d) recommends an adjustment for degradation when estimating exposure point concentrations for use in a baseline risk assessment. At the request of EPA Region N, degradation was not assumed to occur in the calculations presented here. See Appendix E for a discussion of the potential impact of degradation at this Site.
Summary tables of the constituents of potential interest selected for quantitative evaluation are presented in this report in two ways. First, in accordance with U.S. EPA risk assessment
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guidance (U.S. EPA, 1989d), all data including samples reported as below detection limit (BDL)
were used to calculate average constituent concentrations. Tables 2-4 through 2-11 list range
of detection limits (the sample quantitation limits), the frequency of detection, minimum and
maximum reported values, average (arithmetic mean) and upper 95% concentrations of the
constituents of potential interest in each sampled medium at the Site. The average and upper
95% concentrations presented in these tables were derived using all relevant data, including BDL
values as described above. If a constituent was not detected in a medium or area (i.e. all
analyzed samples are BDL) then the constituent was assumed not to be present in that
medium/area. These instances are identified on the data summary tables as "ND". As
previously stated, and as prescribed by EPA, the upper 95% (and maximum) concentrations
presented in these tables were used as the exposure point concentrations in the exposure
assessment.
Second, in accordance with Region IV Supplemental Risk Assessment Guidance (U.S. EPA,
1991b), average values were calculated without incorporating BDL values. Appendix A contains
this data analysis and Tables A-2.1 through A-2.8 present the frequency of detection, minimum,
maximum and arithmetic mean concentrations of constituents detected in all sampled media,
not including BDL samples. As in Tables 2-4 through 2-11, if a constituent was not detected in
a medium/area, then the constituent was assumed not to be present and the constituent
concentrations are reported as 'ND".
2.4 Comparison to Off-Site Samples
In addition to sampling on-Site media, several off-Site media were sampled in the RI. Off-Site
ground water samples were taken at areas potentially affected by the Site. Off-Site samples were
taken for soil and fish at locations suspected not to be affected by the Site. Off-Site ground
water samples were taken at the 26 locations shown in Figures 2-12 through 2-16, primarily to
the east, north and west of the Site. Ground water samples were analyzed for phenolics
including pentachlorophenol, isopropyl ether, and PCDDs/PCDFs. Off-Site surface soil samples
were collected at the following off-Site locations: wells C-3, C-9, C-11, and boring X-1. These
samples were analyzed for acid extractable phenolic compounds. In addition, the surface soil
sample from boring X-1 was analyzed for compounds on the TAL/TCL lists and for
PCDDs/PCDFs. Fish samples were taken from a control pond located about three miles
southwest of the Site. Fish were analyzed for pentachlorophenol, pentachloroanisole and
PCDDs/PCDFs. The off-Site levels of constituents identified in this sampling effort are presented
in Table 2-12.
Maximum detected concentrations for most constituents in off-Site ground water ,were greater
than concentrations measured in on-Site samples except for phenol in the Western Area, 2,4-
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dichlorophenol in the Eastern Area, and 2,4,6-trichlorophenol, pentachlorophenol, isopropyl ether
and dioxin in the Eastern and Former Lagoon Areas. In surface soil, all maximum detected
concentrations in off-Site samples were less than on-Site samples except for phenol in Areas A,
C and D. In subsurface soil, all maximum detected concentrations in off-Site samples were less
than on-Site samples except for phenol in Area C. No constituents were detected in fish from
the off-Site Control Pond.
DegradatioA
The poteAlial llpper b0lJAd asslJmed risl<s estimated iA this base Ii Re risk assessment aooolJnt for
the fast that PGDDs/PGDFs aAd pheAolio oompollAdS in soils aAd sedimeAts degrade. The
poteAtial for ooAstitllent degradalioA is based oA the late aAd traAsport properties of the
oonstitueAt. /\ppendbt le 1 contains a disoussion of tho potential fate and traAsport of eaoh
oonstituent of iAterest at the Site. As discussed in /\ppeAdilt E: 1, all of tho oonstituoAts will
degrade iA eaoh of the media of poteAtial iAterest. The amouAt of degradalioA eicpeoted in the
different media is ooAslitueAI aAd eAviroAmeAI spooifio. Due to the laol< ol ooAslitueAI speoifio
data iA oertaiA media, degradation faotors were ORiy applied to the Site's soil aAd sedimeAt data
for pheAolios aAd diOldAs. IA this evaluatioA, biodegradalioA was the ORiy loss mechanism
ooAsidered in the seleotioA of aegradatioA faotors. While the degradatioA factors usea iA the
baseliAe risl< assessmeAt de not el<plioitly aooouAt for aegradatioA aue to photolysis, aAd R1ay
thus underestiR1ate degradation, they also ao ROI aooount for Site speoilio faotors, suoh as a
red used supply of OlEygeA 00R1pared to the experiments from whioh the degradation faotors were
aeri•;ed, that oould lead to lower aegradation rates.
Based on a literature re•,•iew aAd summary of the degraaatioA rates reported for 2,3,7,8 TCDD
(U.S. E:PA, 198§), this baseliAe risl< assessmeAI assumes a hall life of 12 years for all of the
PGDDs/PCDFs. Half lives for pheAolios (pheAol, 2, 1 diR1ethylphenol, 1,6 diAitro o oresol, 1
nilrophenol, aAd peAtaohloropheAol) iA soil sysleR1s have beeA reportea to raAge froR1 OAe aay
for pheAol to 3Q days for 1,6 diAitro o oresol (Medvede•,' aAd Da•JidoY, 1072; Murthy et al., 1970;
Overoash et al., 1982; Sudharl<ar Baril< aAd SelhuAalhan, 1978; Versar, Ins., 1970; Versohueren,
1977).
This baseliAo risl< assessment ooAservati>Jely assumes that all pheAolio ooR1pouAds iA soils aAd
sediR1eAts at the Site ha,•e a half life of 60 days. This is twioe the highest half life reported iA the
literature. This baseliAe risl< assessmeAt uses 60 days beoause the available literature ORiy
reported half lives for siic of the twel•;e phenolio ooR1pouAds that are ooAslituents of potential
interest at the Site. VVhile it is possible that some of the pheAolio oompounds that are
constituents of poteAtial interest at this Site have half lives of greater than 30 days, it is unlil<el'f
beoause the literature investigated non ohlorinateel as 'Nell as highly ohlorinated speoies,
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all<ylates speoies, ans nitrophenols. Thus, all of the basis types of phenols founs at the Site
have boon in•,<estigates in the literature. ~le¥eftholess, in orser to ensure Iha! publis health is
prnteo!os, the baseline risk assessment assumes that ii tal1es at least two times longer for
phenolio oompounss to segraso on the Sile than the longest reportes limo in the literature.
Seolion 9.0 of this report presents tho results of an in septh literature survey of tho potential lor
phenolio oompounss to segraso in surfaeo soil, subsurfaoo soil ans sosiment.
R;\PUBS\PAOJECTS\0845008\000.S2 2-10 June. 1992
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DRAFT
ATTACHMENT 3
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5.0 RISK CHARACTERIZATION
Risk characterization is the step in which the U.S. EPA approach estimates potential assumed
risks to receptors potentially exposed to constituents at a site. This approach may overestimate
potential upper-bound assumed risk due to the use of many conservative assumptions.
In this section as required by the EPA, two general types of potential health risks are
characterized for each of the potential exposure scenarios: potential upper-bound assumed
noncarcinogenic risks from chronic exposures and potential upper-bound excess lifetime
assumed carcinogenic risk. Throughout this baseline risk assessment, the EPA characterization
of potential adverse effects, i.e. carcinogenic and noncarcinogenic, is employed. Use of this
terminology does not imply that constituents evaluated for potentially carcinogenic effects may
cause cancer. For many compounds classified as "carcinogen" by the EPA, no evidence of
carcinogenicity has been reported in humans. Thus the term 'carcinogen" may only indicate that
the compound has been associated with cancer in laboratory animals, and therefore, that EPA
conservatively assumes it may also cause such effects in humans.
The potential for exposed people to suffer potential adverse noncarcinogenic, as defined by EPA,
chronic health effects is determined by comparing the potential exposure doses estimated in
Section 4.0, to reference doses (RfDs) derived by the EPA and RfDs derived by ENSR following
EPA prescribed methods. The result of this comparison is expressed as a Hazard Index (HI)
which is a conservative measure of the potential for adverse health effects to occur. The
measure is conservative because it is designed to overestimate potential adverse effects. Thus,
estimated Hazard Indices that are of regulatory concern do not necessarily, and in many cases
do not, indicate that adverse effects will be manifested. The HI is equal to the estimated
potential exposure dose divided by the RID. When this ratio exceeds unity, the estimated
potential exposure is greater than the allowable exposure and the potential for adverse health
effects may exist. When it is less than one, the estimated exposure is less than the allowable
exposure and no adverse health effects are expected.
Potential upper-bound assumed carcinogenic risks are estimated by multiplying the potential
exposure doses estimated in Section 4.0 by the upper 95% bound of the carcinogenic potency
estimate derived by the EPA. This upper 95% bound is called the cancer slope factor (CSF) by
the EPA. Potential upper-bound excess lifetime assumed carcinogenic risks are expressed as
the excess hypothetical chance, over and above background, that a person has of getting cancer
over the course of a lifetime (70 years). The estimated upper-bound excess lifetime assumed
R: \ PUBS\ PROJECTS\ 084 5008\ 000. S5 5-1 June, 1992
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ENSl
cancer risks are estimates that are conservative because they are based upon assumptions that are likely to overestimate potential risk.
The characterization of potential assumed noncarcinogenic adverse health risks is discussed first (Section 5.1), followed by a discussion of estimated potential assumed upper-bound excess lifetime cancer risks (Section 5.2). The characterization of these assumed risks follows EPA prescribed methods. Section 5.3 summarizes the results found here. [8eotioR !i.1 discusses the 13oteRtial el/eat of degFadatioR OR assumed FiSl(s. J
5.1 Potential Assumed Noncarcinogenic Risks
Tables 5-1 through 5-9 summarize the potential assumed noncarcinogenic risks, expressed as hazard indices, to the potential receptors evaluated in this baseline risk assessment. Hazard indices are calculated for each pathway, as follows:
Hazard Index = A/8
where: A = Chronic Average Daily Dose (mg/kg-day)
B = Oral or Inhalation RID (mg/kg-day)
If two exposure routes are included in a pathway, the total pathway-specific hazard index is computed by this equation:
Total Hazard Index = A + B
where: A = Hazard lndexx
B = Hazard Index.,
where, for example: x = inhalation
y = ingestion
Potential noncarcinogenic assumed risks estimated for current Site use are presented in Tables 5-1 and 5-2 and potential future noncarcinogenic assumed risks are presented in Tables 5-3 through 5-9.
5.1.1 Potential Current Exposure Scenarios
None of the potential hazard indices estimated for current potential receptors and PEPs exceed unity, indicating that adverse noncarcinogenic health effects are not expected to occur in any
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current receptors. Indeed, the estimated total potential hazard indices (a maximum total
potential hazard index of 0.028 [0.008] for the current on-Site worker [looal Fesidenl,] Table 5-
2-fe-4+) indicate that even if potential exposures are increased by 30-f-lOOt times, adverse
noncarcinogenic health effects would still not be expected to occur because the potential hazard
index would remain less than unity. Thus, for potential current receptors, a [•;of)'] large margin
of safety exists.
5.1.2 Potential Future Exposure Scenarios
If the Site remains commercial/industrial, then the potential hazard index [indioes ] for the
potential future local resident [s are] receptor is estimated to be below unity (0.755, Table 5-3),
indicating that adverse noncarcinogenic effects are not expected to occur. Similarly, the
potential hazard indices for both future on-Site workers (total potential hazard index of
0.029 [0.0003§], Table 5-8) and for future construction workers (total potential hazard index of
0.01, Table 5-9) are well below unity indicating that adverse noncarcinogenic effects are not
expected to occur in these potential receptors.
If the Site were to become residential, an unlikely future land use given that the current increase
in commercial/industrial development is expected to continue, then additional hypothetical
receptors might potentially be exposed to constituents on the Site. The potential adverse I
assumed noncarcinogenic health risks for hypothetical [on Silo] future on-Site residents
estimated in this baseline risk assessment are presented in Tables 5-4 through 5-7. Each Table
presents the potential hazard indices for a hypothetical future on-Site resident living on a different
area of the Site. It is important to note that the Areas evaluated in the baseline risk assessment
were based on Site sampling of discrete former process areas of the Site to most accurately
characterize the Site and assist in the planning of potential remedial actions. The analysis of the
hypothetical future on-Site resident by discrete area was intended to assist in this process and
not intended to reflect any plans for development of the Site. In fact, some of the areas
evaluated in this baseline risk assessment could not be developed independently because of
direct access issues. Area C which lies near the Fire Pond, for example, could not be developed
for residential use without also developing other areas of the Site through which road access to
Area C could be obtained. The same is true for Area A, which lies on the north eastern area of
the Site, and is bounded by railroad tracks to the east, privately owned residential property to
the north and privately owned commercial/industrial property to the west and south. Regardless
of which area of the Site is evaluated, all of the hazard indices estimated for potential exposures
to constituents in soils, sediments, surface waters and fish are less than unity (Tables 5-4
through 5-7). This indicates that even if, hypothetically, the Site were to become residential,
constituents in the soils, sediments, surface waters and fish would not be expected to pose any
adverse assumed noncarcinogenic health risks to hypothetical on-Site residents.
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Only potential exposures to consti_tuents in ground water, assuming that on-Site ground water is used as a hypothetical drinking water supply, result in estimated potential hazard indices that approach or (in the case of a hypothetical on-Site future resident using ground water under the Eastern Area (Tables 5-4 and 5-5)) exceed, unity. Because hazard indices estimated for all PEPs are summed and the hazard indices associated with hypothetical ground water use are relatively large compared to the hazard indices for all other PEPs, the total potential hazard indices for the I hypothetical future on-Site resident also approach or HiR the ease el the Eastem Area)) exceed unity.
The total potential hazard index exceeds unity for hypotheUcal on-Site residents #1 and #2 (due to assumed consumption of Eastern Area ground water as drinking water) and hypotheUcal on-Site resident #3 (due to assumed consumption of Former Lagoon Area ground water as drinking water and incidental ingestion of surface soil in Area CJ. The majority of the hazard index in Eastern Area ground water is attributable to 2.4-dichlorophenol (1.44 of the total 1.54). The majority of the hazard index in Former Lagoon Area groundwater is attributable to pentachlorophenol and dioxin (0.56 and 0.21, respectively), and in Area C surface soils to pentachlorophenol (0.23). Even though some hazard indices approach or exceed unity, noncarcinogenic health effects are not expected because large uncertainty factors were used to derive the RfDs upon which the potential hazard indices are [iRdm< is J based and because the assumptions used to estimate potential exposures to constituents in ground water probably overestimate the potential exposures of most people.
Because surrounding local off-Site residents are using city water as a potable water supply, it is likely that hypothetical on-Site future residents would also use city water rather than ground water as a potable water supply. If the hypothetical on-Site residents do use city water, as is I very likely, then the estimated potential hazard indices would be [ decrease to more than 1 ,000 times] below unity, indicating that no adverse noncarcinogenic health effects would be expected even for future hypothetical on-Site residents. This indicates that remediation of ground water is not likely to be required based on assumed non-carcinogenic risk.
Section 8.0 presents recommendations for remediation of ground water and other media at the Site based on assumed risk. Section 9.0 compares risk-based target clean-up levels with standards and other applicable and relevant or appropriate requirements (ARARs). In some cases, although remediation may not be required based on assumed risk, recommendations for remediation may be made based on ARARs or other factors such as soil clean-up levels for the protection of ground water.
5.2 Potential Assumed Carcinogenic Risks
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Tables 5-10 through 5-18 summarize the potential upper-bound excess lifetime cancer risks to the potential receptors evaluated in this baseline risk assessment using the approach required by EPA guidance. The upper-bound excess lifetime cancer risk is calculated for each pathway as follows:
Upper-Bound Excess Lifetime Cancer Risk = A * B
where: A = Lifetime Average Daily Dose (mg/kg-day)
B = Oral or Inhalation Cancer Slope Factor ({mg/kg-day)'')
If two exposure routes are included in a pathway, the total pathway-specific upper-bound excess lifetime cancer risk is computed by this equation:
Total Upper-Bound Excess Lifetime Cancer Risk = A + B
where: A = Upper-Bound Excess Lifetime Cancer Risk.
B = Upper-Bound Excess Lifetime Cancer Risky
where, for example: x = inhalation
y = ingestion
Potential upper-bound excess lifetime cancer risks estimated for current Site use are presented in Tables 5-10 and 5-11. Potential future upper-bound excess lifetime cancer risks estimated in this baseline risk assessment are presented in Tables 5-12 through 5-18. As stated before, the EPA procedures used in this baseline risk assessment and set forth in the EPA guidance are conservative and therefore may overestimate potential risks. Thus, these estimated potential assumed risks should not be viewed as representing actual risks.
5.2.1 Potential Current Exposure Scenarios
The total potential upper-bound excess lifetime cancer risk-fst estimated for current local residents is 8.12E-04 [€Lee 04 ) (Table 5-10) and for current potential on-Site workers is 3.52E-03 (2.0?E; 03 ) {Table 5-11). These estimates represent the summed assumed risks for each potential pathway evaluated for the receptors. As stated previously, these summed assumed risks are based on the combination of individual assumptions which are intended to result in a reasonable maximum assessment of potential exposure and risk, but which may be represented by combinations of assumptions which exceed reasonable maximum exposures. The net result is an estimate of potential assumed risk which may overestimate any actual risks at a Site. This
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EN31.
is especially true for the current on-Site worker who is assumed to be potentially exposed to
surface soil in all Areas of the Site, yet current work activities occur primarily in Area D.
Except for assumed risks from exposure to surface soil in Area C, all current risks fall within or l below U.S. EPA's target risk range for Superfund sites, indicating that remediation of surface
soils in Areas A, Band D, sediment, surface water, and ground water may not be needed based
upon risks estimated for current potential use.
In addition, the majority of the estimated potential upper-bound cancer risks are from potential
exposures to dioxins and furans. As discussed in Appendix D, the EPA's assumption about the
potential toxicity of dioxin to humans and the CSF for dioxin derived based upon their
assumptions (almost sertainly overnstimates J may overestimate the carcinogenic potential of
dioxin by at least 9 to 16 fold, and more if a threshold dose-response relationship is assumed.
The U.S. EPA ORD is currently re-evaluating the status of the CSF for dioxin. It is unknown at
this time what the result of the [when i;;p,o, will somplete their] re-evaluation will be. The current
EPA CSF for dioxin was used to estimate the potential assumed risks in this report. However,
use of (a more] alternative scientifically appropriate and defensible CSFs would decrease the
estimated potential upper-bound cancer risks to below or very near 1 E-04, which falls at the
higher end of the EPA's target risk range for Superfund sites.
5.2-2 Potential Future Exposure Scenarios
If the Site remains commercial/industrial, then the total potential upper-bound excess lifetime
cancer risks for a potential future local off-Site resident are estimated following EPA methods to
be 8.16£-04 (G.eaie 04 ] (Table 5-12). All PEPs for potential soil, surface water, sediment and
ground water exposures evaluated for the future local off-site resident except potential exposure
to surface soil in Area C, fall within or below the EPA's target risk range for Superfund sites. The
majority of this estimated potential assumed risk is associated with potential exposure to dioxin.
As discussed above and in Appendix D, alternative estimates of dioxin's carcinogenic potential
are available. II the more scientifically appropriate and defensible CSFs had been employed in
the baseline risk assessment in lieu of the EPA's current CSF, the estimated potential upper-
bound assumed risks would have decreased by about 10-fold or more to between -f2t4E-05 and
-f2t4E-04. The total potential upper-bound cancer risk associated with remaining constituents
is 6£-06 (41e 07), which is within (eelow tho J EPA's target risk range for Superfund sites.-{-j3oiflt
of departure.]
The estimated total potential upper-bound excess lifetime cancer risks for both future on-Site
workers (total potential upper-bound risk of 3.52£-03 (2.G7E: Ga] Table 5-17) and for future
construction workers (total potential upper-bound risk of 6.B?E-05 Table 5-18) were estimated
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following EPA methods. All PEPs evaluated for the future on-Site worker and the construction
worker fall within or below EPA's target range except potential exposures to surface soil in Area
C. It should be noted that, if the alternative and scientifically more defensible estimates of
dioxin's carcinogenic potential are used, the estimated upper-bound potential risks decrease to
less than 1 E-06 for all areas except surface soil in Area C regardless whether a threshold or non-
threshold dose-response relationship is assumed. These estimated potential upper-bound
assumed risks indicate that, with the exception of surface soil in Area C, remediation of Site
surface or subsurface soils is not necessary if the future use of the Site remains
commercial/industrial, as is most likely.
If the Site were to become residential, an unlikely future land use given the current increase in
commercial/industrial development which is expected to continue, then additional hypothetical
receptors might potentially be exposed to constituents on the Site. The potential upper-bound
excess lifetime cancer risks for hypothetical on-Site future residents were estimated following EPA
methods and are presented in Tables 5-13 through 5-16. Each Table presents the potential
upper-bound excess lifetime cancer risks for a hypothetical future on-Site resident living on a
different area of the Site. Hypothetical on-Site residents' potential exposure to surface soil in
Areas A and D and subsurface soil in Areas A and B results in estimates of potential assumed
risk below EPA 's point of departure. Hypothetical on-Site residents' potential exposure to surface
soil in Area B results in a potential assumed risk within EPA's target risk range (2.67E-05).
Hypothetical on-Site residents' potential exposure to surface soil in Area C results in a potential
assumed risk that exceeds EPA's target risk range (4.26E-02). Potential exposure of hypothetical
on-Site residents to subsurface soil in Area C results in a potential assumed risk within EPA's
target risk range (4.37E-06). Constituents assumed to be carcinogenic were not detected in
subsurface soils in Area D.
Hypothetical on-Site residents' potential exposure to surface water (1.18E-06) and sediment
(1.12E-06) in the discharge streams and ditches, and sediment (3.56£-06) in Fire Pond, result
in potential assumed risks within EPA's target risk range. As discussed below, potential
exposures to Fire Pond surface water result in potential assumed risks that exceed EPA 's target
risk range. [ All hypothetical luture residents livin§ en any el the lour areas ef the Site have
estimated u13per bound excess liletime cancer risks ef less than 1 E 0§ fer potential ei(pesures
te constituents in all soils in Areas .0. and 0, and all sediments and surface waters in the
dischar§e streams and ditches. Potential residential exposure lo surface soil in Areas B and C
result in assumed riol1s §Feater than 1 E 0§.)
The majority of the potential assumed risk for the-fsetsoil, surface water and sediment PEPs is
attributable to dioxin. As discussed above, the potential assumed upper-bound cancer risks
associated with dioxin are almost certainly overestimated. Estimated potential upper-bound risks
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would decrease to less than 1 E-06 for all of the PEPs associated with these environmental
media, with the exception of surface soil in Area C, if (\he ffieFe] available alternative and
scientifically defensible CSFs for dioxin were employed. If dioxin is assumed to have a threshold
dose-response relationship, as is scientifically appropriate and defensible, then none of the potential exposures to dioxin and related compounds from the PEPs estimated in the baseline
risk assessment, with the exception of surface soil in Area C, are expected to pose a health risk. This indicates that even if, hypothetically, the Site were to become residential, any constituents
in soils from Areas A, B and D, all sediments in Fire Pond and the discharge streams and
ditches, and the surface water in the discharge streams and ditches, would not be expected to
pose any unacceptable carcinogenic risks to hypothetical on-Site residents.
[All of] The potential upper-bound assumed risk associated with consumption of fish from Fire Pond is within EPA 's target risk range (8.16E-05, Tables 5-13 to 5-16) and is associated with
potential exposure to dioxins and furans. The estimated potential assumed risks would decrease
to less than 1 E-05 if-f#!&j-alternative available and scientifically appropriate and defensible CSFs
for dioxin had been employed. If dioxin is assumed to have a threshold dose-response
relationship, then the potential exposure to dioxin in Fire Pond fish is not expected to pose a health risk. In addition, given the pond's physical and biological characteristics, it is unlikely that
local residents will eat fish from the Pond.
Potential exposures to constituents via two [three] other PEPs, contact with surface water while
swimming in Fire Pond (1.50E-04), (sonsuffiplion of fish IFOffi J;ire Pond] and consumption of
on-Site ground water from the Eastern and Former Lagoon Areas (5.44E-04 and 1.05E-03),
assuming that on-Site ground water is used as a potable water supply, result in estimated
potential upper-bound excess lifetime cancer risks that exceed 1 E-04-fet. Almost all of the
assumed risk from swimming in Fire Pond (as a resident for 30 years) comes from the potential
dermal absorption of dioxin from surface water while swimming. If the [ffiore] alternative and
scientifically appropriate and defensible CSF for dioxin were used, estimated potential upper-
bound risks would decrease to about 1 E-05, which is within EPA's target risk range. If dioxin is
.assumed to have a threshold dose-response relationship, then dioxin is not anticipated to pose a cancer risk. [lhe polonlial upper bound risl< is well below 1 Ee OS.] In addition, given that the
average depth of Fire Pond is three feet and Fire Pond is considered unattractive for swimming,
and that it is unlikely that people will inhabit the Site, the potential swimming exposures in Fire
Pond assumed in the baseline risk assessment are unlikely to occur.
The estimated potential upper-bound excess lifetime cancer risk for use of on-Site ground water
as potable water supply by hypothetical future residents in Area D (1.48E-07, Table 5-16) is less
than the EPA's point of departure risk of 1 E-06, indicating that remediation of the o~-Site ground
water in the Western Area of the Site is not needed. Only the estimated potential upper-bound
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excess lifetime cancer risks associated with hypothetical future potable use of ground water in
Areas A and B (Eastern Area), and C (Former Lagoon and Cellon Process Area), exceed the
EPA's target risk range of 1 E-06 to 1 E-04 {Tables 5-13, 5-14, 5-15). Because estimated upper-
bound assumed risks are assumed to be additive, the estimated total upper-bound cancer risks
for hypothetical on-Site residents in these areas also exceed the target risk range. In Areas A
and B, the Eastern Area, the majority of the estimated potential assumed risks are associated
with exposure to dioxins and furans {Tables 5-13 and 5-14). Consequently, if the alternative
more scientifically appropriate and defensible CSFs for dioxin had been used to estimate
potential upper-bound cancer risks, the estimated upper-bound assumed risks in these two areas
would fall within the EPA's target risk range.
As discussed above, because surrounding off-Site residents are currently using city water as a
potable water supply and the Site is also currently supplied by city water lines, it is likely that the
hypothetical on-Site future residents would also use city water, and not ground water as a
potable water supply. If the hypothetical on-Site residents do use city water, as is likely, and the
alternative [FRoro) scientifically defensible and appropriate CSFs for dioxin were used, then the
estimated potential assumed risks would decrease to within the EPA's target risk range.
Potential residential exposures to constituents in ground water via inhalation of volatiles while
showering results assumed risks well before EPA 's point of departure. Thus, assumed risks from
exposure to on-Site ground water while showering are not of concern at this site.
5.3 Summary of Estimated Potential Assumed Risks
This baseline risk assessment has shown that no potential adverse assumed noncarcinogenic
health risks are expected to occur following potential exposure to constituents in any of the
environmental media evaluated (surface soils, subsurface soils, sediments, surface water, fish
and ground water). The baseline risk assessment has also shown that, with the exception of
potential exposure to surface soil in Area C, hypothetical future use of on-Site ground water as
a potable water supply, and hypothetical future use of Fire Pond as a swimming hole and source
of fish for consumption by hypothetical on-Site residents (which is an unlikely occurrence), the
estimated potential assumed risks associated with all PEPs fall within or below the U.S.EPA's
target risk range. If alternative and scientifically appropriate and defensible estimates of dioxin's
carcinogenic potential are used, then only hypothetical future on-Site residential exposures to
surface soil in Area C and hypothetical future use of on-Site ground water from the Former
Lagoon Area as a potable water supply result in estimated potential upper-bound cancer risks
that exceed the U.S.EPA's target risk range for Superfund sites.
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[Impact sf Qegradation Factors
As the ssientilis literature supports, this baseline risl< assessment assumes that all sonstituents
of potential interest degrade naturally in tho en¥ironment (see Appendix E 1). As discussed in
Section 2.!i, degradation !asters weFe only applied to phenolic compounds and PCQQ/PCQFs
in soils and sediment. Tho potential impast of the degradation fastoFS on resulting estimated
potential assumed risl1s was e¥aluated. Only the impact on potential assumed sarsinogenis risl1s
weFe e¥aluated here because all soil and sediment ha;!ard indices are below unity indicating little
or no potential lor ad¥erse nonsarninogenis health offests oicists.
Tho majority of assumed risk estimated at the Site is attributable to dioxin in surtaso soil in Area
C and in ground water. Se¥eral other potential eHposure pathways were found to ha¥e estimated
potential assumed rislcs greater than 1 E G!i, whioh is the midpoint of EPl\'s target risl1 range.
Most ol this assumed risk is also attributable to diOJcin. If no degradation faster had been
applied to soil or sediment, the potential assumed upper bound oiIsess ris!Is lor oicposures to
diOJdn in soil and sediment would almost double (i.e. increase two times). Potential assumed
risl1s attributable to pentashlorophenol would inoreaso more than two times, yet this change
would still not result in a signilisanl change in the results ol the baseline risl1 assessment
because most of tho 13otontial assumed risl1 is attributable to dioxin.
Table !i 1 O demonstrates tho offost of degradation on both dioicin and pentashloropheno! in all
soil and sediment evaluated in the baseline risl< assessment. Surtase soil in Area C had the
highest 13otential assumed risl1s lor the Site lor o•~ery reseptor e¥aluated in the Baseline ris!I
assessment. As shown in Table !i 10, potential assumed risl1s from pentashlorophenol lor all
reseptors in all media inoreaso approicimately one lo two orders el magnitude lor the roseptors
with potential long term eicposures. Potential assumed risl1s lrom dioicin increase approicimately
\>,\lo times lor reseptors 'Nith 13otential long term exposures. Removal of degradation does result
in an insrease in potential assumed risl1s from pentashlorophenol for local resident tres13assers,
on Site worl1ers and hypothetical on Site residents, yet it does not substantially alter the o•,erall
estimates of total assumed risl1 lor these Feseptors Because most el the potential assumed risk
at the Site is attriButable to dioicin.
Therefore, the applisalioA of degradation factors in this baseliAe risl1 assessment does not
subslaAtially alter the total estimated potential assumed risl<s from the Sile. i;Jemo¥al el
degradatioA from this assessment also has little ellesl on selestion of the areas of the Site that
potentially would require remediation.
EPA's risl1 assessment guidance (U.S. EPA, 1080d) states that degradation should be tal<eA into
accouAt when estimating potential assumed rislcs from constituents at Superfund sites. Sullisient
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evidenso eicists to expest that the organis sonstituents of interest at this Site will degrade o~•er
time. Thus, assoun!ing for degradation is appropriate. However, predistin§ the ma§nilude of
de§radation is more dillis1Jlt given the limited data ~•ailable in the ssienti!is literature; and also,
the potential for dillerenses between sondi!iens at the Sile and in the laboratory experiments
from whish the de§radation rates were deri·;ed to allost tho assumption !hat !he e1cperimentally
derived rates are dires!ly applisable to tho Sito.
Gi·,•en these sonserns, this baseline risl< assessment has e·,,al1Ja!ed the allest of degradation.
That anal'jsis, presented in more detail above, demonstrated that ins!uding or not ineludin§
de§radation had little allest on whish soils or sediment at this Sile may potentially need
remediation. This lask of a prastisal effest ossurs 13eeause either, the potential assumed risl<s
from ·;arious environmental media are so small that even 1A•hen tho effost of dO§radation is
removed, the potential assumed risl<s still do not mcoeed EPA's point of departure; or the i
potential assumed rislrn of selest environmental media and areas of the Site eicseed EPA's points l of departure and remo·,•ing the effest of degradation would net shan§e that outsome.
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---- - ----
TABLE 5-1 -REVISED
SUMMARY TABLE -LOCAL OFF-SITE RESIDENT
CURRENT SCENARIO -POTENTIAL NONCARCINOGENIC RISK
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
CONSTITUENT·.
PHENOL
2-CHLOROPHENOL
2-NITROPHENOL
2,4-DIMETHYLPHENOL
2,4-DICHLOROPHENOL
4-CHLORO-3-METHYLPHENOL
2,4,6-TRICHLOROPHENOL
2,4-DINITROPHENOL
4-NITROPHENOL
2,3.5,6-TETRACHLOROPHENOL
2-METHYL-4,6,-DINITROPHENOL
PENTACHLOROPHENOL
ISOPROPYL ETHER
TOTAL TCDD-TE
TOTAL
Notes:
NC ~ Not calculated.
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12-Jun-92
RN: 01
1.44E-08
NC
6.0IE-07
3.33E-07
NC
NC
NC
6.0BE-06
l.91E-06
NC
NC
NC
NC
NC
8.94E-06
NC
2.23E-06
NC
NC
NC
NC
NC
NC
NC
NC
NC
5.99E-07
NC
NC
2.82E-06
--
NC
1.I0E-05
NC
2.93E-06
1.41E-05
2.61E-06
NC
3.25E-04
NC
5.26E-05
3.44E-05
1.19E-02
NC
NC
l.23E-02
- ---
NC
NC
NC
3.B0E-06
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
3.B0E-06
.. Tr:!r~i·•·····
·····• ilazard Ind;•
SurfftCO Wat.or [1igoation-_& _::
·:·_ Derrn& ·eon.tact.·-.
Fire:Pofld
2.04E-08
5.34E-06
NC
1.48E-05
8.25E-05
NC
NC
NC
3.48E-06
l.33E-06
NC
4.49E-06
NC
NC
1.12E-04
--
.. <,,,.><::: ,J,_~r)\L:J-·,,
l'oteiitiaF• ·•·
-..
Sodi~eiil 'i,igckiO~/k):.
. Demial Cotltaci : .
. <\--··: ,, .. F~~= p~~J/\\\.--==
7.IBE-09
t.58E-06
2.44E-07
I.33E-07
NC
NC
NC
NC
9.34E-07
NC
2.0BE-06
I .49E-06
NC
NC
6.46E-06
----- -
TABLE 5-1 -REVISED
SUMMARY TABLE -LOCAL OFF-SITE RESIDENT
CURRENT SCENARIO -POTENTIAL NONCARCINOGENIC RISK
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
--.. ..
. . .. ····••·••······· ··••·········•··•·············±~l•)··· .. • •....•... ··•··•.·•··::r.:H(~~di·t.Jl••·.•···d·:erxl·;·~~!·•··· .••· \< ~ ():~~'0rident ....... ·.· . • ....... • ~ ?p~~t:ridcnt ··•·· . ~~ ?p~'0f:'i1~•1 · ·=-'=-=::.=:-poteDual'''"''·ccc,:,_,·:, · .__ -,-,=,::::=:::=,::,:x::,.=•:/?:=.>JiillAfi~d-~i-.· . ·--·'?:/iU,iiJ~f'frid~{?/'. \'(l{';J]Jdj1JJf·-:·,.--.
·•·•·••iri~~~i·i:!f.. •·• .. •••••.•i•··\~iftt~••··•·······•· ··•·r••t·.•···sf 2t~:z··&··.······· · ···•·•··•••~tt~;:ttr •••. }• ·····••tt·•·········•·it{ffu~lii~i•··.<••·•·····.
·:=:=:-<?/ p~ 'PJ~d :::.:·· .. -·.: :\·:·:--f:.,-=}w~;~rDtl~lf/:=:'=-·· ::·:.'Hi~i~Ji6'• sti~~ Fro~ Fi~ PJ~~i:+ -.·'•';' Off-Sitc·Area'. = -·:_ (Off-Site Area Groi.indWntcrf
PHENOL NC NC 4.83E-08 9.60E-07 3.67E-06
2-CHLOROPHENOL NC NC NC 8. IJE-05 3. I0E-04
2-NITROPHENOL NC NC 2.62E-06 2.41E-04 9.21E-04
2.4-DIMETHYLPHENOL NC 2.26E-06 2.47E-06 2.69E-06 I.0JE-05
2.4-DICHLOROPHENOL NC 8.91E-05 NC 1.96E-04 7.49E-04
4-CHLORO-3-METHYLPHENOL NC NC NC 3.06E-05 1.17E-04
2,4,6-TRICHLOROPHENOL NC NC NC NC NC
2,4-DINITROPHENOL NC 2.92E-06 2.06E-05 l.44E-04 4.19E-04
4-NITROPHENOL NC NC NC 8.59E-05 3.28E-04
2,3,5,6-TETRACHLOROPHENOL NC 1.19E-06 NC 4.07E-05 1.56E-04
2-METHYL-4,6,-DINITROPHENOL NC NC NC 7.89E-04 3.0IE-03
PENTACHLOROPHENOL NC 3.JIE-05 I .68E-05 2.81E-07 l.07E-07
ISOPROPYL ETHER NC NC NC 5.63E-07 2.ISE-06
TOTAL TCDD-TE NC NC NC NC NC
TOTAL NC l.29E-04 4.25E-05 l.61E-03 6.0JE-03
Notes:
NC -Not calculated.
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-------------------
TABLE 5-1 -REVISED
SUMMARY TABLE -LOCAL OFF-SITE RESIDENT
CURRENT SCENARIO -POTENTIAL NONCARCINOGENIC R
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
CONSTITUENT·
PHENOL
2-CHLOROPHENOL
2-NITROPHENOL
2,4-DIMETHYLPHENOL
2,4-DICHLOROPHENOL
4.CHLORO-3-METHYLPHENOL
2,4,6-TRICHLOROPHENOL
2,4-DINITROPHENOL
4-NITROPHENOL
2,3,5,6-TETRACHLOROPHENOL
2-METHYL-4,6,-DINITROPHENOL
PENTACHLOROPHENOL
ISOPROPYL ETHER
TOTAL TCDD-TE
TOTAL
Notes:
NC -No< calculated.
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4.72E--06
4. 12E--04
I.I 7E--03
3.96E--05
1.13E--03
I.S0E--04
NC
9. I 7E--04
4.2IE--04
2.52E--04
3.S4E--03
I.20E--02
2.72E--06
NC
2.0JE--02
--- - ----
TABLE 5-10 -REVISED
SUMMARY TABLE -LOCAL OFF-SITE RESIDENT
CURRENT SCENARIO -POTENTIAL CARCINOGENIC RISK
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
PHENOL NC NC
2-CHLOROPHENOL NC NC
2-NITROPHENOL NC NC
2.4-DIMETHYLPHENOL NC NC
2,4-DICHLOROPHENOL NC NC
4-CHLORO-3-METHYLPHENOL NC NC
2,4,6-TRICHLOROPHENOL l.87E-II NC
2,4-DINITROPHENOL NC NC
4-NITROPHENOL NC NC
2,3,5,6-TETRACHLOROPHENOL NC NC
2-METHYL-4,6,-DINITROPHENOL NC NC
PENTACHLOROPHENOL NC 3.0BE-10
ISOPROPYL ETHER NC NC
TOTAL TCDD-TE NC l.21E--07
TOTAL l.87E-I 1 l.22E--07
Notes:
NC -Not calculated.
File Name: RSUMCI.WKI RN: 01
12-Jun-92
-------llllil liiiil
NC NC NC NC
NC NC NC NC
NC NC NC NC
NC NC NC NC
NC NC NC NC
NC NC NC NC
5.49E-II 5.19E-I I NC NC
NC NC NC NC
NC NC NC NC
NC NC NC NC
NC NC NC NC
6.12E--06 NC 2.31E--09 7.65E-10
NC NC NC NC
7.72E--04 NC 6.63E--06 l.5 IE--07
7.78E--04 5.19E-1 I 6.63E--06 l.52E--07
- - - - --
TABLE 5-10 -REVISED
SUMMARY TABLE -LOCAL OFF-SITE RESIDENT
CURRENT SCENARIO -POTENTIAL CARCINOGENIC RISK
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
PHENOL
2.CHLOROPHENOL
2-NITROPHENOL
2,4-DIMETHYLPHENOL
2,4-DICHLOROPHENOL
4-CHLORO-3-METHYLPHENOL
2,4,6-TRICHLOROPHENOL
2,4-DINITROPHENOL
4-NITROPHENOL
2,3,5,6-TETRACHLOROPHENOL
2-METHYL-4,6,-DINITROPHENOL
PENTACHLOROPHENOL
ISOPROPYL ETHER
TOT AL TCDD-TE
TOTAL
Notes:
NC -Not calculated.
File N•mc: RSUMCI.WKI
12-Jun-92
RN: 01
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
I.93E--05
I.93E--05
..
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
2.89E--08
NC
I.ISE--06
I.ISE--06
- - -
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
I.47E--08
NC
7. IOE--06
7. 12E--06
-lililil llilil
NC NC
NC NC
NC NC
NC NC
NC NC
NC NC
NC NC
NC NC
NC NC
NC NC
NC NC
4.19E-10 I.60E-10
NC NC
9.82E-10 3.75E-11
1.40E--09 I.97E-IO
- -----
TABLE 5-10 -REVISED
SUMMARY TABLE -LOCAL OFF-SITE RESIDENT
CURRENT SCENARIO -POTENTIAL CARCINOGENIC RISK
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
. ..
CONSTITUEr:iT ••
PHENOL
2-CHLOROPHENOL
2-NITROPHENOL
2,4-DIMETHYLPHENOL
2,4-DICHLOROPHENOL
4-CHLORO-3-METHYLPHENOL
2,4,6-TRICHLOROPHENOL
2,4-DINITROPHENOL
4-NITROPHENOL
2,3,5,6-TETRACHLOROPHENOL
2-METHYL-4,6,-DINITROPHENOL
PENTACHLOROPHENOL
ISOPROPYL ETH ER
TOTAL TCDD-TE
TOTAL
Notes:
NC • Not CA.!culate.d.
File Name: RSUMCI.WKI
12-Jun-92
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Local Off.Site R«ideot ·. :=)\f:\c'ii~t-~ri'(' ,.···
RN: 01
NC
NC
NC
NC
NC
NC
l.26E-10
NC
NC
NC
NC
6. 16E-06
NC
8.06E-04
8.12E-04
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7.0 SOURCES OF UNCERTAINTY
In this section, the assumptions and procedures that introduce the greatest amount of
uncertainty in the baseline risk assessment, as well as their effect on the estimates of potential
assumed risk, are discussed. The discussion of their effect will be qualitative, because in many
instances not enough information exists to quantify the magnitude of those uncertainties.
7.1 Uncertainties Associated with Human Health Evaluation
The potential hazard indices and potential upper-bound excess lifetime cancer assumed risks
presented in Section 5.1 and 5.2 are estimates of potential upper-bound risk that are useful in
regulatory decision making. It is improper to consider these potential assumed risks as
representative of the actual risks to potentially exposed individuals because they were estimated
by making numerous conservative assumptions (i.e. assumptions that overestim.ate potential
exposure and potential risk). Thus, they have uncertainty associated with them. Some of the
assumptions have a firm scientific basis, while others do not. Some level of uncertainty is
introduced into the risk characterization process every time an assumption is made. In
regulatory assessment the methodology dictates that assumptions err on the side of
overestimating potential exposure and risk. The effect of using numerous assumptions that each
overestimate potential exposure and risk is to exaggerate estimates of potential human assumed
risk. Such estimates are useful for regulatory decision making, but do not provide a realistic
estimate of the potential health impacts of waste disposal sites.
This section is divided into subsections that correspond to the four steps involved in the human
health risk characterization process as prescribed by EPA.
7.1.1 Hazard Identification
The baseline risk assessment was based on data generated following U.S. EPA-approved
sampling plans. The list of constituents used in the baseline risk assessment was approved by
U.S. EPA.
7.1.2 Dose-Response Assessment
Accepted practice divides potential health effects of potential interest into two general categories:
effects with a threshold (noncarcinogenic) and effects assumed to be without a threshold
(carcinogenic). The EPA has assigned benchmarks for evaluating a constituent's carcinogenic
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and noncarcinogenic potential. These benchmarks, or dose-response values, are called
reference doses (RfDs) for the evaluation of potential noncarcinogenic effects and cancer slope
factors (CSFs) for the evaluation of potential carcinogenic effects. Dose-response assessments
and the resulting EPA-derived RfDs and CSFs share many of the same sources of uncertainty.
In the discussion below several of the more important sources are presented. Assumptions that
are anticipated to create more uncertainty for one category of effects than the other are noted.
7.1.2.1 Animal-to-Human Extrapolation in Noncarcinogenic Dose-
Response Evaluation
For many compounds, animal studies provide the only reliable information on which to base an
estimate of adverse human health effects. Extrapolation from animals to humans introduces a
great deal of uncertainty into the risk characterization. Some of this uncertainty can be reduced
if a compound's fate and the mechanism by which it causes adverse effects is known in both
animals and humans. When the fate and mechanism for the chemical constituent is unknown,
uncertainty increases. The procedures used to extrapolate noncarcinogenic effects from animals
to humans make conservative assumptions and incorporate several uncertainty factors, such that
overestimation of effects in humans is far more likely than underestimation. Nevertheless,
because the fate of constituents can differ in humans and animals, it is possible that animal
experiments will not reveal an adverse effect that would manifest itself in humans. This can result
in an underestimation of the effect in humans. The opposite may also be true: effects observed
in animals may not be observed in humans, resulting in an overestimation of potential adverse
human health effects.
7.1.2.2 Evaluation of Carcinogenic Dose-Response
Significant uncertainties exist in estimated carcinogenic dose-response. These are due to
experimental and epidemiologic variability, as well as in extrapolating both from animals to
humans and from high to low doses. Three major issues impact the validity of dose-response
assessments used to estimate potential excess lifetime assumed cancer risks: (1) the selection
of a study (i.e., data set) upon which to base the calculations, (2) the conversion to an equivalent
human dose corresponding to the animal dose used, and (3) the mathematical model used to
extrapolate from experimental observations at high doses to the very low doses potentially
encountered at the Site.
Study Selection
Study selection involves the identification of a data set that provides sufficient, well-documented
dose-response information to enable a valid extrapolation. Ideally, human data are preferable
R:\PUBS\PROJECTS\0845008\000.S7 7-2 June, 1992
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to animal data, although adequate human data sets are relatively uncommon. Therefore, it is
often necessary to seek dose-response information from a species that biologically resembles
humans (e.g., with respect to metabolism, physiology, and pharmacokinetics), and where the
route of administration is similar to the expected mode of human exposure (e.g., inhalation and
ingestion). Cancer incidence data should allow for determination of statistically significant
elevations in the occurrence of tumors at specific target organ sites. When multiple valid studies
are available, the U.S. EPA bases CSFs on the one study and site that show the most significant
increase in tumor incidence with increasing dose. In some cases, such as for 2,3,7,8-TCDD, this
selection is done in spite of tumor incidence in other organs and total tumor incidence showing
significant decreases with increasing dose. Consequently, the current study selection criteria
[are aln:lest sertain te] may lead to [substantial) overestimation of potential assumed cancer
risks in humans.
Interspecies Dose Conversion
The determination of human equivalent doses by conversion of doses administered to
experimental animals requires the assumption that humans and animals are equally sensitive to
the toxic effects of a substance, if the same dose per unit body surface area is absorbed by each
species. Although such an assumption may hold for direct acting cytotoxins, it clearly is
erroneous for many indirect carcinogens such as dioxins and furan and likely overestimates
potential risk by a factor of 6 to 12. Further assumptions for dose conversions involve
standardized scaling factors to account for differences between humans and experimental
animals with respect to lifespan, body size, breathing rates, and other physiologic parameters.
In addition, evaluation of risks associated with one route of administration (e.g., inhalation) when
tests in animals involve a different route (e.g., ingestion) requires additional assumptions with
corresponding additional uncertainties.
High-to-Low Dose Extrapolation
. The concentration of constituents to which people are potentially exposed from CERCLA sites
is usually much lower than the levels used in the studies from which dose-response relationships
are developed. Estimating potential health effects at such sites, therefore, requires the use of
models that allow extrapolation of health effects from high experimental to low environmental
doses. These models contain assumptions that may introduce a large amount of uncertainty.
For instance, the EPA CSFs are derived using the upper 95% confidence limit of the slope
predicted by the linearized multistage model. EPA recognizes that this method produces very
conservative risk estimates and that other mathematical models exist. Several dose-response
models are available for low-dose extrapolation. These include the probit, the multi-hit, the logit,
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and the multistage models. These models are generally statistical in character and have little biological basis. In the Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986b), EPA states:
No single mathematical procedure is recognized as the most appropriate for low-dose extrapolation in carcinogenesis. When relevant biological evidence on mechanism of action exists (e.g., pharmacokinetics or target organ dose), the models or procedures employed should be consistent with the evidence. When data and information are limited, however, and when much uncertainty exists regarding the mechanism of carcinogenic action, models or procedures that incorporate low-dose linearity are preferred when compatible with the limited information.
EPA policy is to use the linearized multistage model unless there is adequate scientific justification for using another model. Many countries and U.S. scientists have determined that such justification exists for dioxin.
EPA emphasizes in the guidelines that the upper-bound estimate generated by the linearized multistaged model leads to a plausible upper limit to the risk that is consistent with some proposed mechanisms of carcinogenesis. Such an estimate, however, does not give a realistic prediction of the risk. The true risk is unknown and may be as low as zero. An established policy does not yet exist for using 'most likely' or 'best' estimates of risk within the range of uncertainty defined by the upper-and lower-limit estimates.
7.1.2.3 Compound-to-Compound Extrapolation
Dioxins and furans are a class of compounds that are assumed to be potential human carcinogens. Information on the carcinogenic potential of dioxin and furan is available for only a few species of this class of compounds and the most information is available for 2,3,7,8-TCDD. Potential carcinogenicity of all other members of this class is based on the above mentioned limited information. Therefore, the assumption is made that the risk posed by all other dioxin I and furan congeners can be assessed by adjusting the CSF for 2,3,7,8-TCDD, which is assumed by the EPA to be one the most potentially carcinogenic dioxin or furan. Thus, exposure point concentrations for all dioxin and furans are converted to 2,3,7,8-TCDD equivalents using EPA's toxic equivalent approach. Toxic equiva/ency factors (TEFs) for 2,3,7,8-substitued congeners range from 1.0 to •o•, and are •o" for a// non-2,3,7,8-substituted congeners. Although this approach has some validity, CSFs based upon direct experimental data for each dioxin and furan isomer would be more desirable.
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7.1.3 Exposure Assessment
Exposure assessment consists of two basic steps: estimation of potential exposure point
concentrations, and estimation of potential human dose. The more important sources of
uncertainty associated with these two steps are discussed below.
7.1.3.1 Estimation of Exposure Point Concentrations
In many samples, one or more constituents were not detected by the analytical procedures. This
baseline risk assessment makes the health protective assumption that the constituent could have
been present in that sample at a concentration below the instrument's limit of detection. Thus,
instead of assuming that these samples had a concentration of zero, they were assigned a
concentration equal to one-half of the limit of detection. This may result in an overestimate of
potential assumed risk for some constituents.
As prescribed by EPA, the exposure point concentrations used in the exposure assessment are
the upper 95th percent confidence interval on the arithmetic mean constituent concentration in
a particular medium and area of potential interest. In certain cases, such as when sample size
is small or variation between samples is large, the upper 95th confidence interval is greater than
the maximum detected constituent concentration in that medium/area. In those cases, the
maximum concentration was used. Either value, however, will likely lead to an overestimation
of actual exposure at the Site since it is assumed that the potential receptors are exposed to the
(near) maximum constituent concentration for the entire duration of exposure. As the data show,
most constituents were not even detected in most samples, thus the assumption that all potential
exposures are to the (near) maximum concentrations will result in an overestimation of actual
exposures and resulting estimates of potential assumed risk.
In addition, the estimation of airborne chemical concentrations of Site-derived constituents is
uncertain. In the absence of air monitoring data a screening level approach was used. This
approach assumed that the level of respirable particles downwind of the Site is at all times the
PM10 level measured at the Raleigh-Durham monitoring Site and that all the airborne particles
are derived from Site soil and that there are no particles in the air from other sources. While
there is some uncertainty concerning the actual level of Site-derived particles that would be
present in the air downwind of the Site, this assumption is likely to result in an overestimate of
potential exposure because the perimeter of the Site is lined with trees and other brush cover.f
In last, most el the Site is 001,ered with grass, 1,egelation, buildings or f)a11ement. Very little, ii
any, dirt or dust is exf)osed at the surlase. Thus, it is 11ery lil<ely that the estimated e1Ef)osure
f)Oint sonsentrations in the air 01,1ereslimate the astual sonstituent sonsentmtions and therefore
overestimate the f)Otential risk.]
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All of the constituents of potential interest at the Site are known to naturally degrade in the
environment. The baseline risk assessment assumed no degradation of organic constituents
even though the scientific literature contains abundant evidence that phenols and other organic
compounds degrade (also see Appendix E). The failure to account for degradation leads to an
overestimate of potential assumed risk in this report. Because some degradation of constituents
will occur at this Site, the risks presented in this report that assume that degradation does not
occur will be overestimates of any actual risks, if any, associated with exposure to constituents
at this Site.
[IA IRe llaseliRe risl( assessmeRI, eRly J)ReRelis semJ)0URdS aRd PCDDs/PCDFs were ass1Jmed
te degrade iR sails aRd sediment. lseJ)repyl elRer in sails and sedimeRI, aRd all senstit1JeAIS iR
gre1JRd water, sw1ase water aRd fish were Rel e•,al1Jated ler degradatieR d1Je le a lasl1 el
60RSti!IJ9Rt SJ)esilis er eRvireRmBRI SJ)eSilie data. TRe allseRSe el degradatien !asters fer all
senstit1Jents in all media leads te IJRsertainty in !Re eicpes1Jre assessment.
Uneertainty is alse asseoiated witR the degradatien !asters 1Jsed in the llaseline risk assessmeRt
sinoe the laeters 1JSed ass1Jme !Rat all less eeeurs IRFSUQR lliode§radatien. As Ap,::,endiic E 1
deserilles, e!Rer lme•,vn less meehanisms may Ile J)Otentially signilieant ler sertain eenstit1Jents
in sertain media. In addition, the degradatien faster tal1en from IRe literat1Jro 1or pen
tasRleropRenel was 1Jsed lor all J:JRenelis semJ)e1Jnds. Phenolic somJ)ellnd sJ)esifis !asters we1Jld
res1JII in different estimates ef ellpes1Jre J)eint sensenlratiens 1er !Re J)Renoliss eYal1Jated in IRS
llaseline risl1 assessment.
There is alse 1Jnsertainty assesiated with IRS SJ)esifie de§radatien !asters 1Jsed in the llaseline
risl1 assessment llesa1Jse !Re rate ef de§mdatien e1 any sonstit1Jent ls spesifis to tRe J)artis1Jlar
envirenmental and misrellial senditions el tRe medium. Given IRis 1JRsertainty, tRe de§radation
rates FBJ)erted in tRe literat1Jre and 1Jsed Rero reprnsent senser.•ati•,e estimates for general
envirenmental senditiens.
TRe ass1Jmed time el ellJ)8S1Jre is alse a faster 'NhlsR leads te 1Jnsertainty in tRe IJSe ef
elegmelation 1aotors in IRe llaseline risk assessment. All J)Reneliss and TCDD TEs in sails and
sediment were de§raded /or the rese,:iter s,:iesifis ell,:JOSIJFe d1Jratien ass1Jmed in the llaseline risk
assessment fer llotR J)Otential s1Jrrent and f1Jt1Jre e><J)esures. This will res1Jlt in !Re e•,erestimatien
of ,:ietential f1Jt1Jre e><J)8S1Jres llesa1Jse allhe1Jgh the degradatien faster asoe1Jnts fer tRe
de§radation that is mc,:iested to eso1Jr ever the d1Jralion el !Re J)otential exJ)es1Jre, the
degradatien that eoo1Jrs from the time of sam,:iliRg te !Re time the mc,:ies1Jre is ass1Jmed to lle§in
has net Ileen asse1Jnted for in this assessment. If this time had Ileen asso1Jnted for, !Re
C><,:ies1Jre ,:ioiRI oenoentratiens 1Jsed in !Re f1Jl1Jre assessment(sl weuld Ra1,•e Ileen !ewer. As a , ,
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Fes1a1lt, the peteAtial ass1a1mea FiSl<s estimates feF the f1a1tuFe soil aAa seaimeAt sseAaFios wol!lel I
ha11e beeA lower thaA reportea iA the baseliAe risl< assessmeAt J
7 .1.3.2 Estimation of Exposure Dose
When estimating potential human doses (i.e., intakes) from potential exposure to various media,
several assumptions are made. Uncertainty may exist, for example, in assumptions concerning
rates of ingestion, frequency and duration of exposure, and bioavailability of the constituents in
the medium. Typically, when limited information is available to establish these assumptions, a
conservative (i.e., health-protective) estimate of potential exposure is employed. This is likely to
lead to an overestimate of potential assumed risk.
This baseline risk assessment has followed EPA guidance and estimated the potential
carcinogenic and noncarcinogenic risks for a theoretical reasonably maximally exposed individual
(RME). For instance, for potential carcinogenic effects (future scenario), the hypothetical on-Site
resident is assumed to be on the Site 50 of 52 weeks a year for 30 years, eat fish from Fire
Pond, swim in Fire Pond, and ingest Site related soils and sediments. A real person is unlikely
to engage in these activities for this long period of time, but the activity patterns of people are
difficult to accurately characterize. From a regulatory point of view, it may be appropriate to
perform a public health evaluation on such a hypothetical person. However, any actual risks are
likely to be less than the potential upper-bound risk presented in this baseline risk assessment.
7.1.4 Risk Characterization
The potential assumed risk of adverse human health effects is characterized based on estimated
potential exposures and potential dose-response relationships. Two important additional sources
of uncertainty are introduced in this phase of the baseline risk assessment: the evaluation of
potential exposure to multiple compounds and the combination of upper-bound exposure
estimates with upper-bound toxicity estimates.
7.1.4.1 Risk from Multiple Compounds
As prescribed by EPA, once potential exposure to and potential assumed risk from each
constituent is estimated, the total upper-bound potential risk posed by the Site is determined by
combining the estimated potential health risk from each of the constituents. Presently, potential
non-threshold effects are added unless evidence exists indicating that the constituents interact
synergistically (a combined effect that is greater than a simple addition of potential individual
effects) or antagonistically (a combined effect that is less than a simple addition of potential
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individual effects) with each other. For virtually all combinations of compounds, little if any
evidence of interaction is available. Therefore, additivity is assumed. Whether assuming
additivity leads to an underestimation or overestimation of risk is unknown.
For noncarcinogenic effects, the hazard index (HI) should be summed for all constituents that
have the same or similar toxic endpoints (U.S. EPA, 1989d). The toxic endpoint is defined as
the most sensitive noncarcinogenic health effect used to derive the RID or other suitable dose-
response value (U.S. EPA, 1989a). In this risk baseline risk assessment, as a first step the
potential His have been summed regardless of the similarity of their toxic endpoints. Thus, the
summed HI may not appropriately estimate the potential risk posed by exposure to some groups
of constituents. Rather, it may overestimate the potential risk, because exposure to such
constituents may not result in additive effects in the human body if mechanisms of action and
toxic endpoints are different for such constituents.
Summation of His for all compounds is required by EPA (U.S. EPA, 1989d) as a preliminary
analysis to determine if the HI exceeds 1.0. If the HI does not exceed the criterion, then there
is no need to perform an advanced analysis based on toxicity endpoint. If, however, the HI
exceeds 1.0, then the HI analysis should be redone so that only those compounds exhibiting the
same or similar toxicity endpoints are evaluated collectively. In this baseline risk assessment
only one pathway-specific HI exceeds unity: the HI for ground water use as a potable water
supply by the hypothetical future on-Site resident (e*seeEleEI l!Rity) (1.05). Because the majority
of the hazard index for this pathway is attributable to one constituent, 2,4-dichlorophenol (1.44),
a detailed, endpoint-specific analysis is unnecessary.
For a different hypothetical on-Site resident, although none of the pathway-specific His exceed
unity, the total HI for this receptor does exceed unity (1. 12). The majority of this hazard index is
attributable to pentachlorophenol in ground water and soil, and isopropyl ether in ground water.
Because the non-carcinogenic health endpoints for these two constituents are different, a
detailed analysis of specific toxic endpoints would result in hazard indicies less than unity for
each of these two constituents. [Besa1Jse the peteAtial e*pes1Jre is llAlil(ely te ecc1Jr, the mere
EletaileEI aRalysis was Rat pertermeEI. )
7.1.4.2 Combination of Several Upper-bound Assumptions
Generally the goal of a baseline risk assessment is to estimate an upper-bound, but reasonable,
potential risk. Such an upper-bound estimate can be arrived at in several ways, depending how
conservative one wants the final estimate to be. Generally in the past, baseline risk assessments
for CERCLA sites have combined several upper-bound assumptions to estimate potential risks.
R:\PUBS\PROJECTS\0845008\000.S7 7-8 June, 1992
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Most of the assumptions about exposure and toxicity used in this baseline risk assessment are
representative of statistical upper-bounds or even maximums for each parameter. The result of
combining several such upper-bound assumptions is that the final estimate of potential exposure
or potential risk is conservative. This is best illustrated by a simple example. Assume that
potential risk depends upon three variables (soil consumption rate, constituent concentration in
soil and CSF). The mean, upper 95% bound and maximum are available for each variable.
One way to generate a conservative estimate of potential risk is to multiply the upper 95%
bounds of the three parameters in this example. Doing so assumes that the 5% of the people
who are most sensitive to the potential carcinogenic effects of a constituent will also ingest soil
at a rate that exceeds the rate for 95% of the population, and that all the soil these people eat
will have a constituent concentration that exceeds the concentration in 95% of the soil on Site.
The consequence of these assumptions is that the estimated potential assumed risk is
representative of 0.0125% of the population (0.05 x 0.05 x 0.05 = 0.000125 x 100 = 0.0125%).
Put another way, these assumptions overestimate risks for 9,999 out 10,000 people, or 99.99%
of the population. Thus the majority of people will have a much lower level of potential risk. The
conservative nature of the potential risks estimated by the superfund risk assessment process
is not generally recognized. In reality, the estimates are more conservative than outlined above,
because more than three upper 95% assumptions are used to estimate potential assumed risk(s)
in each evaluation presented in this baseline risk assessment.
Alternatively, if a single upper 95% assumption of carcinogenicity is combined with average (50th
percentile) assumptions for soil concentration and soil ingestion rate, the resulting estimates of
potential risk still over predict risk for 99% of the population exposed to the Site. This is a
conservative approach that substantially overestimates the 'average' level of potential risk posed
by a site.
The risk assessment approach used here employed upper 95% bounds or maximums for most
exposure and toxicity assumptions. Thus it produces estimates of potential risk two to three
orders of magnitude greater than the risk experienced by the average member of the potentially
exposed populations.
7.1.5 Summary of Sources of Uncertainty in the Human Health Evaluation
The large number of assumptions made in the risk characterization could potentially introduce
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a great deal of uncertainty. While this could potentially lead to underestimates of potential risk,
the use of numerous upper-bound assumptions guarantees that overestimates of potential risks
will result. As discussed elsewhere in the report, any one person's potential exposure and
subsequent assumed risk are influenced by all the parameters mentioned in the text and will vary
on a case-by-case basis. Despite inevitable uncertainties associated with the steps used to
derive potential risks, the use of numerous health-protective assumptions will most likely lead to
an overestimate of potential risks from the Site.
7.2 Uncertainties Associated with the Ecological Evaluation
A large number of assumptions that can lead to uncertainty are made in the evaluation of the
potential for assumed adverse ecological effects at the Morrisville Site. The assumptions made
in this evaluation err on the side of conservatism and will thus likely overestimate the potential
for adverse effects. A qualitative discussion of the major sources of uncertainty associated with
the ecological evaluation is presented below.
Extrapolation of the potential for community, population, or ecosystem effects from the
examination of one or more indicator species is a major source of uncertainty for both the
aquatic and terrestrial analyses. The underlying assumption is that potential effects on one
species are representative of effects on the particular ecosystem being investigated. For this
assessment, bluegills were chosen to represent potential effects on aquatic ecosystems,
muskrats were chosen to represent potential effects on mammalian organisms in terrestrial
ecosystems, and belted kingfishers were chosen to represent potential effects on avian species
in terrestrial ecosystems. Each of these choices represents a potential source of uncertainty.
It is difficult to predict how an adverse effect on an individual organism would affect the
ecosystem as a whole. U.S. EPA (1989a) states that 'concentrations that are acutely toxic to
single species are usually no much greater than concentrations that are toxic at the ecosystem
level. Whereas, concentrations that are toxic in chronic single species are, in most cases,
overprotective of ecosystems.• This indicates that chronic toxicity evaluation results for the
aquatic indicator species may be overly conservative for use in evaluating potential effects to
aquatic ecosystems. Similar evaluations of acute and chronic toxicity tests are not available for
terrestrial receptors.
Another source of uncertainty exists in the prediction of bioavailability of constituents in each
environmental medium. The estimation of an average daily dose for ecological receptors does
not address the bioavailability of constituents. In addition, certain physical characteristics of
aquatic ecosystems, such as surface water hardness, are not known for this Site, but these
characteristics may affect the bioavailability of the constituents of potential interest. The results
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of these factors may be either an overestimate or an underestimate of potential ecological
effects.
In several cases in the aquatic assessment, LOEL guidance values were used as conservative
benchmark concentrations because of the lack of species-specific exposure test data for bluegill.
Differential species sensitivity may result in these values being underestimates or, more likely,
overestimates of potential acute or chronic toxicity for the bluegill. In the aquatic assessment
of potential acute effects, it is very likely that the aquatic receptors will be exposed to lower
constituent concentrations than the maximum concentrations assumed in this analysis. Many
of the acute toxicity studies from which acu!e LOEL guidance values were derived were 96-hour
exposure studies. It is unlikely that aquatic organisms will be continuously exposed to maximum
constituent concentrations for 96 hours.
Both aquatic and mammalian receptors were assumed to spend large portions of their lives
exposed to the arithmetic mean concentration for the particular exposure medium/area. This
is an unlikely occurrence because it does not address degradation of the constituents,
remediation, or animal migration. Assuming continuous chronic exposure to mean constituent
concentrations at these locations may lead to an overestimate of potential adverse effects.
Belted kingfishers, for example, will probably not spend their entire lifetime on the Site. However,
in order to conservatively evaluate this potential receptor, it was assumed that the belted
kingfisher would consume only fish and that half of its diet would come from Fire Pond fish. It
was also conservatively assumed that there would be no depuration of TCDD from the body
tissues of the kingfisher. The conservative assumptions applied in the mammalian and avian
evaluations are likely to result in an overestimate of the potential for adverse effects.
Using EPA guidance documents and best professional judgement, the assumptions applied in
the aquatic and terrestrial assessments were chosen to be conservative and protective. The
overall effect of combining these conservative assumptions is likely to result in overestimates of
the potential for adverse ecological effects at the Morrisville Site.
R:\PUBS\PROJECTS\0845008\000.S7 7-11 June, 1992
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:i%\ ¾•';__ ,,,~, ..
~ '1\
~:;: .
"-•,,
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9.0 CLEAN-UP LEVELS EVALUATION
The purpose of this section to identify both risk-based target clean-up levels (RBTCLs) and
remediation goals for constituents in various environmental media at the former Koppers
Company, Inc. Site in Morrisville, North Carolina. The RBTCLs were derived based on the
information presented in Sections 1.0 through 8.0 of the Baseline Risk Assessment report for this
Site.
As described in Section 2.2, the constituents of potential interest at the Site include phenolic
compounds, isopropyl ether, and PCDD/PCDF. The results of the baseline risk assessment
show that remediation of the Site may be required based on the potential for increased assumed
carcinogenic risk from exposure to pentachlorophenol and PCDD/PCDF in various media of
interest. Because approximately one hundred percent of the potential assumed excess cancer
risk estimated in the baseline risk assessment is attributable to these two constituents, the list
of constituents of potential interest can be shortened to two constituents of interest:
pentachlorophenol and PCDD /PCDF. This Section presents the results of a clean-up levels
evaluation for pentachlorophenol and PCDD/PCDF in all media evaluated at the Site.
Section 9.1 describes the methodology for calculating RBTCLs based on the results of the
human health and ecological evaluations. Section 9.2 presents a comparison of the RBTCLs
with applicable and relevant or appropriate requirements (ARARs) for the constituents of interest.
Section 9.3 summarizes the results of the clean-up levels evaluation. Detailed information about I
the derivation of RB TC Ls[, applisalion of ~BTCLto the Sile Femedialion pmsess,] ond a detailed
discussion of the results of the clean-up levels evaluation can be found in Appendix G.
9.1 Derivation of Risk Based Target Clean-up Levels (RBTCLs)
The baseline risk assessment used a series of assumptions about the constituents present on
the Site and the behavior of people or ecological receptors who may be exposed to the Site, in
order to establish a hypothetical relationship between the concentration of a constituent on the
Site and a potential assumed risk associated with that constituent concentration. This
hypothetical relationship is used to derive risk-based target clean-up levels (RBTCLs) for the two
constituents of interest in the various media at the Site. Section 9.1.1 describes the method for
calculating RBTCLs based on the human health evaluation presented in the baseline risk
assessment. Section 9.1.2 describes the methods used to evaluate-fat potential assumed risks
to ecological receptors, how ecological RBTCLs could be derived, and why they are not.
A:\PUBS\PROJECTS\0845008\000.S9, 0845•008-700 9-1 March, 1992
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9.1.1 Human Health Evaluation
Potential exposure dose was estimated for all assumed hypothetical receptors using conservative
assumptions about assumed exposure to constituents in various media. The potential exposure
doses estimated in the baseline risk assessment, combined with estimates of potential assumed
toxicity resulted in estimates of constituent-specific potential assumed risk. Potential assumed
risks to hypothetical receptors were estimated for potential exposures to constituents assumed
to be carcinogenic by EPA in surface and subsurface soils, surface water bodies, sediments, and
ground water. Potential assumed carcinogenic risks were also estimated for potential exposures
to pentachlorophenol and PCDD/PCDF in fish from the ponds under study.
The human health RBTCLs for constituents in an environmental medium were calculated by
comparing the ratio of an existing constituent concentration to the potential assumed risk
estimated for that exposure, with the ratio of the RBTCL to a target risk level. This equation can
also be expressed as:
RBTCL = Existing constituent concentration x target risk level
Potential assumed carcinogenic risk
where: the existing constituent concentration is the existing reasonable maximum exposure
concentration of the constituent in that medium or area; the potential assumed risk is the
constituent and medium-specific assumed risk estimated in the baseline risk assessment; and
the target risk level is equal to a value within EPA's target risk range (e.g., 1 E-04, 1 E-05, or 1 E-
06). [(e.§., 1 it 10-<, 1 x 10·5, or 1 it 10 .. H· As described in Section 2.3, the reasonable maximum
exposure concentrations used in the baseline risk assessment are equal to the upper 95th
confidence limit on the arithmetic mean concentration, or the maximum concentration, whichever
is lower.
(As ElesoribeEl iA SootieA 9.1.1.1, RBTGLs were EleriveEl for the hypothetioal reoeptors iA the two
· · hypothetioal future Site use oeAditioAs evaluated iA the baseliAe risl1 assessrneAt The RBTGLs
for eaoh future Site use ooAElitioA are preseAted iA AppeAEliit G.
PoteAtial mtposures to soil aAEl seElirneAt iAoluEleEl aA aEljustrneAt for de§radatioA el phoAolio
oornpouAds aAd PGDD/PGDi; iA the baseliAe risl1 assessrneAt. ,o,pplioatioA el de§radatioA
lac\ors to el\istiAg, rneasureEl GOAGOAtratioAs of ooAstitueAts results iA rnore aosurate estirnates
of poteAtial assurned risl1, aAd follows E:P/\ risl1 assessrneAt guidaAoe (U.S. ECPA, 1989d). The
Elegraded ooAslitueAI ooAoeAtratioAs were used iA the estirnatioA of poteAtial assurned risl1 lrorn
OlEposure to soil aAd sedirneAt. The RBTGLs for peAtaohloropheAol OREi PGDD/PGDi; were
derived by oornpariAg the OJtisliAg ooAGeAtratioA with the poteAtial assurned risk estirnated usiA§
R:\PUBS\PAOJECTS\0845006\000.S9, 0845-008-700 9-2 March, 1992
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a degraded eenstituent eeneentratien. This was dene se that the resulting RBTGb inserperates
the adjustment fer degradatien that is assumed te ecsur ever the eicpesure peried.
Sectien 9.1.1.2 discusses RBTGbs derived fer petential sail and sediment eicpesure based en
degradalien rates used in the baseline rislE assessment, and RBTGbs deri,•ed ler sail and
sediment eicpesure based en alternate degradalien rates lor pentachlerephenel.
t
[Petenlial Future Sile Use Gendiliens)
RBTCLs were developed for two potential future Site use conditions. The first condition assumes
that the Site remains commercial/industrial. This is the most likely future Site use scenario, as
current development in the area has been commercial/industrial in nature. The second, and less
likely scenario, assumes that the Site is developed for future residential use. The potential for
residential development at this Site is considered [highly] unlikely because recent development
in the area has been commercial/industrial, and the Site is currently occupied with commercial
enterprises. In addition, institutional controls, such as placing a land-use restriction on the deed
for the property preventing residential use, can and will be introduced by Beazer to assure that
its portion of the Site remains commercial/industrial.
Hypothetical receptors were evaluated for each of the two potential future Site use conditions
evaluated in the baseline risk assessment. On-Site Workers and Local Off-Site Residents were
evaluated for the commercial/industrial Site use scenario. The Local Off-Site Resident evaluation
includes the potential exposures of teenagers trespassing on the Site. At the request of EPA,
hypothetical On-Site Resident receptors were evaluated for potential future residential use of the
Site. Appendix G presents the RB TC Ls derived for pentachlorophenol and PCDD /PCDF for each
of these receptors.
[Degradalien el Genstituenls
The baseline rislE assessment assumed that phenelics and PGDD/PGDF degrade naturally ever
lime. This was based upen a literature re1,•iew whieh indicated that these censtituents degrade
in sails. Given this evidence, and that EP/\ risk assessment guidance (U.S. ePA, 1989d) allews
lor eensideralien el degradalien when estimating pelenlial assumed rislEs, degradalien el
phenelic cempeunds and PGDD/PGDF was assumed le eccur in sails and sediments. Based
upen review and cemment by e;p,o,, a mere detailed literalurn review el degradatien el phenelic
cempeunds was undertalEen and is summari2ed in Table 9 1. This review previded eenslusive
evidenee of degradalien el phenelic eempeunds in a variety el eendiliens including aerebic and
anaerebic sails, and aerebie and anaerebic aqueeus cenditiens. Thus, it is apprepriale Iha!
degradalien sheuld be censidered when estimating petenlial assumed rislES and alse when
R:\PUBS\PROJECTS\0845008\000.S9, 0845-008-700 9.3 March, 1992
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Eleri>,1ing RBTGbs. The more EletaileEI review EliEI, however, report slower ElegraElalion rates than
assumeEI by the baseline risk assessment (presenleEI in Sections 1.0 through B.0 of this report).
In particular, the baseline risl1 assessment assumeEI a ElegraElation rate (half life) el 60 Elays fer
phenolic oompounEls, inoluEling pentaohlorophenol. This was baseEI upon Eloubling the highest
reporteEI ElegraElation rate (of 30 Elays) for penlaohlorophenol. The more resent literature review
iElentilieEI a maieimum ElegraElation rate of 178 Elays for pentaohlorophenol in aerobic soils anEI
a mai1imum of 4 .2 years of anaerobic soils. BaseEI upon this e',1iElenoe, two sets of RBTGbs for
pentaohlorophenol were EleriveEI to represent a oonservati>,e estimate of eieposure al this Sile:
RBTGbs based on the degraElation rates useEI in the baseline risl1 assessment; and RBTCbs
baseEI on alternate ElegraElations rates. The RBTCbs baseEI on alternate degraElation rates
inoluEle a ElegraElalion half life of penlaohlorophenol in surface soil of 1 year (about Elouble the
longest half life reporteEI for penlaohlorophenol) anEI in subsurface soil anEI sediment of § years
(slightly greater than the maieimum hall life reporteEI in the literature).
DegraElalion half lives anEI RBTGbs EleriveEI assuming degraElation shoulEI be ohecl1eEI against,
anEI possibly limileEI by, tv.10 factors. The first is that when the half life is useEI to baol1 oaloulate
from meisting constituent oonoentrations to oonslituent oonoentrations al the time a facility ceased
operation, reasonable oonoentrations al the time of cessation of operation shoulEI be predioleEI.
The half life of 1 year for pentaohlorophenol used to Elerive alternate RBTCbs in surface soil
preEliots that the eidsting average surface soil oonoentration of pentaohlorophenol Area C (38§
mg/l1g) woulEI have averageEI 3992 mg/l1g in 197§, the year that operations oeaseEI at this Sile.
The estimaleEI pentaohlorophenol concentration at the time of cessation is reasonable inElioating
that the half life of 1 year in surface soil is also reasonable. Similarly, the half life of 12 years for
Elioi1in (useEI in the baseline risl1 assessment), anEI the alternate half life of 6 years for
pentachlorophenol in subsurface soil anEI seEliments, also preEliots reasonable concentrations
al the time of cessation in 1976.
The sooonEI factor is to limit the RBTGb baseEI upon ElegraElalion al a constituent oonoenlration
that protects against assumeEI potential aoute effects as well as assumeEI potential ohronio
effects. Because no aoute Elose response value for pentachlorophenol was available, the sub
ohronio reference dose for pentaohlorophenol (U.S. El=lA, 1990a) was useEI in this evaluation.
The pentaohlorophenol oonoentration in surface soil that is protective of sub ohronio effects was
estimated assuming a 1 § l1g ohilEI ingests 200 mg of surface soil every Elay. The maieimum
conoenlralion of penlaohlorophenol in surface soil that is protective of sub ohronio effects is 22§0
mg/l1g. The RBTGbs for pentaohlorophenol are less than this oonoentration. If ohronio RBTCbs
haEI been higher, ii would neeEI to have been limited at the oonoentration protective of assumeEI
potential sub ohronio effects.
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Similarly, the RBTGLs for PGDD/PGO,' in surface soil, subsurface soil anEI seeliment, anel
pentaohlorophenol in subsurface soil anel seeliment Elo not eicoeeEI the concentration proteotive
acute effects, anEI thus, the RBTGLs are protective of assumes sub chronic as well as assumes
chronic effects.
The soil anel seeliment RBTGLs EleriveEI here anEI presenteEI in Appeneliic G, inoluele Elegraelation.
Two sets of RBTGLs 'Nore EleriveEI for pentaohlorophenol for each relevant receptor, RBTGLs
using Elegraelation rates uses in the baseline risk assessment, anel RBTGLs using alternate
Elegraelalion rates talion from the literature anel summarizes here. The reoommenelalions for
potential remeeliation at the Sile (see Section 9.3) were bases on the RBTGLs EleriveEI using
alternate Elegraelalion rates. The RBTGLs Eleriveel for alternate Elegraelation rates are proteotive
of long term effeots anel are proteolive of potential assumes sub ohronio effeots. AEIElitionally,
the half lives can be uses lo preeliot reasonable levels of constituent present al the Site at the
time operations were oeaseEI in 197§.
Constituent concentrations in surface water, grounEI water anel fish were not aeljusleEI for
Elegraelalion in the baseline risl1 assessment, nor in the clean up levels evaluation, because
oonstiutent concentrations neeel to meet mcisling stanelarels in surface water anEI grounEI water,
anel no information was available in the soienlifio literature to thoroughly evaluate Elegraelation
of the constituents of interest in fish.)
9.1.2 Ecological Evaluation
The ecological evaluation presented in Section 6.0 and Appendix G of the baseline risk
assessment showed that potential assumed risks to ecological receptors for all constituents,
except PCDD/PCDF in Fire Pond surface water, were at the level of •no concern• as defined by
EPA. This indicates no need for remediation of surface water in Fire Pond or Medlin Pond for
these constituents. The assumed potential exposure of aquatic species to PCDD/PCDF in Fire
Pond surface water was evaluated in the baseline risk assessment using a screening toxicity
value required by EPA. The results of this evaluation indicate that potential aquatic exposures
to PCDD/PCDF in Fire Pond are of •high concern• as defined by EPA. However, as discussed
in Appendix G, the potential exposure of aquatic organisms to PCDD /PCDF in Fire Pond surface
water [is not) are likely to not be of 'high concern" as defined by EPA, when alternate, more
realistic estimates of potential toxicity are used to evaluate potential exposures of aquatic
species.
Specific methodologies exist for determining RBTCLs for potential human exposures based on
allowable risk levels. Similar specific guidance is not available for aquatic receptors. However,
the calculated clean-up levels designed to be protective for human health (Section 9.3) will
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results in a ten-fold reduction in surface water concentrations of PCDD/PCDF. This reduction
will also be protective of aquatic species in Fire Pond.
9.2 Comparison of RBTCLs and ARARs
When remediation goals for media or areas of the Site are considered, the RBTCLs and all
applicable standards can be compared in order to determine the most reasonable and
appropriate remediation measures to pursue. The relevant ARARs identified for the constituents
of interest in this evaluation are North Carolina standards and federal MCLs for
pentachlorophenol and 2,3,7,8-TCDD. Soil target clean-up levels for the protection of ground
water have also been derived for these two constituents (Keystone, 1992).
This section presents a summary of the comparison of maximum measured constituent
concentrations, as directed by U.S. EPA Region N, in various media with RBTCLs derived for the
hypothetical receptors, State of North Carolina and federal ARARs, and soil clean-up levels for
the protection of ground water. A detailed discussion of this comparison is presented in D
Appendix G. Comparison to average constituent concentrations is a/so scientifically and ,.
statistically appropriate, but is not presented in this document at the request of U.S. EPA Region
IV.
[Consliluenl specific RBTCLs deri11ed lor each recefJ\or were oomf)arod '"''ilh ei<isling average,
RME; and R'laJ(imum conoentralions, and Stale and federal AR.'\Rs. Potential reoeplors are
assumed to contact the various R'!edia of interest repeatedly over many years. As disoussed in
Appendil( G, oomparison of RBTCLs to average sonstituenl ooncentralions most ascuralely
depicts potential assumed m<posures to oonoenlrations of oonstituenls over !he exposure period.
Thus, reR'!edial goals should ae seleoted lo f)roteol lor tho average conoenlralions al oonsliluenls 1
at the Site. Comparison of RBTCLs and ARARs can ae made to oonsenlralions other than Iha
average; RBTCLs and ARARs could 13e somf)ared lo the RME or mai,imum constituent
sonsontralion to estimate the upperR'lost bound of fJOtential assumed ei1posure. Al the request
of EPA, comparisons of RBTCLs and /\RARs with average, RME lIB.ct maidmum constituent
sonoentrations wore presented in detail in Appendii< G, and are summari2ed here.)
Existing maximum concentrations of constituents, as directed by EPA, were compared with
RBTCLs, soil target clean-up levels for the protection of ground water, and State and federal
ARARs. RBTCLs presented on Table 9-1 were derived for the 1E-04, 1E-05 and 1E-06 risk
levels. ( RBTCLs for penlashlorophenol in soil on Taale 9 :, are represented as !he R'iaJdmum
sonsenlralion lo protest for assumed sul3 shronio effects, or the RBTCL derived al Iha 1 E: 5 risl,
level assuming the alternate degradation rates used in this evaluation, which ever is the lower
1,aluo. RBTCLs for PCDD/PCDF in soil on Table 9:, were derived assuming the 1 E: 5 risl, level
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and the degradation rates used in the baseline risl1 assessment. Maicimum aonaentrations were
used in this part of the analysis beaause the model used to deri,•e these olean up levels requires
oomparison with maicimum oonstituent oonoentrations in soil. The analysis is summarized on
Table 9 2, and is presented in detail in Appendilc G.J RBTCLs at the 1E-5 risk level are the focus
of this evaluation because the likely future use of this Site is commercial/industrial1. The results
of this analysis indicate that existing maximum constituent concentrations exceeded RBTCLs (at
the 1 E-5 risk level), ARARs, or soil target clean-up levels for the protection of ground water, only
in the following media:
• Surface Soil in Area C
• Subsurface Soil in Area C
• Surface Water in Fire Pond
• Fish in Fire Pond
• Ground Water in the Former Lagoon Area
• Ground Water in the Eastern Area
In Area C surface soil, existing (RMe and] maximum concentrations of pentachlorophenol
exeeded RB TC Ls at the 1 E-06 risk level for local off-Site residents, and RBTCLs at the 1 E-05 risk
level for on-Site workers in the commercial/industrial Site use scenarios. In Area C surface soil,
existing maximum concentrations of PCDD/PCDF exceeded the RBTCLs at the 1£-04 risk level
for the local off-Site resident and the on-Site worker in the commercial/industrial Site use
scenarios. In Area B surface soil, the maximum measured concentration of PCDD/PCDF
exceeded the RBTCL at the 1 E-06 risk level for the on-Site worker in the commercial/industrial
Site use scenarios.
In the residential Site use scenarios, the maximum concentration of pentachlorophenol in Area
C surface soil exceeded the RBTCL at the 1 E-04 risk level for the hypothetical on-Site resident.
The maximum concentrations of PCDD/PCDF in Area Band Area C surface soil were exceeded
by the RBTCLs at the 1 E-05 and 1 E-04 risk levels, respectively, for the hypothetical on-Site
resident.
In addition, (the 1 E e risk level for residential Site use only. In Area C surlaoe soil, existing
average, RME and maicimum PCDD/PCDF oonoentrations elcoeeded all RBTCLs for both the
oommeroial and hypothetioal residential Site use soenarios. e] existing maximum concentrations
1 Recent development in the area has been commercial/industrial, and the Site is currently
occupied with industrial enterprises. In addition, institutional controls, such as placing a land-use
restriction on the deed for the property preventing residential use, can and will be introduced by
Beazer to assure that its portion of the Site remains commercial/industrial.
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of pentachlorophenol and PCDD /PCDF exceeded the soil target clean-up levels for the
protection of ground water.
In Area C subsurface soil, existing maximum pentachlorophenol concentrations exceeded the
soil target clean-up level for the protection of ground water. Maximum concentrations of
PCDD/PCDF in Area C subsurface soil exceeded the RBTCLs at the 1 E-06 risk level for the local
off-Site resident and the on-Site worker in the commercial/industrial Site use scenarios.
Maximum concentrations of pentachlorophenol and PCDD/PCDF in subsurface soil in Area C
exceeded the RBTCLs at the 1 E-06 risk level for the hypothetical on-Site resident in the future
residential Site use scenarios.
In the commercial/industrial Site use scenarios, the maximum concentration of PCDD/PCDF in
Fire Pond surface water exceeded the RBTCL for the local off-Site resident at the 1 E-06 risk level.
In the future residential Site use scenarios, the maximum concentration of PCDD/PCDF in Fire
Pond exceeded the RBTCL for the hypothetical on-Site resident at the 1 E-04 risk level.
In sediment in the discharge stream from Fire Pond, maximum PCDD/PCDF concentrations
exceeded the RBTCL for the local off-Site resident at the 1 E-06 risk level. In Fire Pond, the
maximum sediment concentration exceeded the RBTCL for the hypothetical on-Site resident at
the 1 E-06 risk level.
In ground water in the Eastern Area, maximum pentachlorophenol concentrations exceeded
RBTCLs at the 1E-05 risk level. In Former Lagoon Area ground water, maximum
pentachlorophenol concentrations exceeded RBTCLs at the 1 E-04 risk level. Maximum
pentachlorophenol concentrations in both areas exceeded the MCL for pentachlorophenol. In
ground water in the Former Lagoon Area and Eastern Area, maximum concentrations of
PCDD/PCDF exceeded RBTCLs at the 1E-04 risk level and also exceeded the proposed MCL
for PCDD/PCDF.
Maximum concentrations of PCDD/PCDF in fish tissue from Fire Pond exceeded RBTCLs at the
1 E-05 risk level for both the local off-Site resident and the hypothetical on-Site resident. In Medlin
Pond, maximum concentrations of PCDD/PCDF in fish tissue exceeded RBTCLs at the 1 E-06 risk
level for the local off-Site resident. (Average, RME and maidmum oonoenlralions, however, did
not mmeed RBTGLs al the 1 E e risl< level deri>,ed !or either the oommersial/induslrial or
residential Site use ssenarios.]
(In Fire Pond surtase water, eiEisting average, RME and maximum sonsenlralions of
PGDD,'PGDF were belsw RBTGLs at the 1 E e risl< level derived !or sommersial/industrial Silo
use, but mmeeded RBTGLs at the 1 E e risk level deri>,ed !or hypothelisal residential Site use.
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~isliRg avoFage, RME: aRd mailimum 69RSeRlralieRS el PGDD/PGDF iR fish frem Fire PeRd
eimeeded the RBTGbs al the 1 E: § Fisk level derived fer 13elh peteRtial futuFe Site use SSeRaries.
IA greuRd water iR the FeFmer bageeR aRd E:astern AFOas, average, RMe aRd mai(imum
69R69RtratieRS el peRtashlerepheRel aRd PGDD/PCDF 9JE69eded RBTGbs (at the 1 e e risl1 level)
aRd MGbs. Average, RME: aRd mai(imum 69RSeRlratieRS el PGDD/PCDF iR these twe SR Sile
greuRd wateF aFOas alse eimeeded the State greuRd water staRdard feF 2,3,7,8 TGDD.)
9.3 Summary and Recommendations
This Section has reviewed the clean-up levels evaluation presented in Appendix G of the baseline
risk assessment. The human health RBTCLs were determined using the potential assumed
carcinogenic risks estimated in the baseline risk assessment, which was conducted following
EPA guidance and in accordance with standard risk assessment methodology. Parallel analyses
for ecological receptors suggest that remedial action is not necessary and, therefore, RBTCLs
are not required for ecological receptors.
Human health RBTCLs were derived for potential future receptors assuming two different
potential future Site use conditions. At this time, no decision has been made regarding the I
future use of the Site. However, it is [highly) unlikely that the Site will become residential in the
future because recent development in the area has been commercial/industrial, and the Site is
currently occupied with industrial enterprises. In addition, institutional controls, such as placing
a land-use restriction on the deed for the property preventing residential use, can and will be
introduced by Beazer to assure that its portion of the Site remains commercial/industrial.
As described in Section 9.2 and in Appendix G, on-Site surface and subsurface soil in Area C,
surface water and fish in Fire Pond, and on-Site ground water in the Former Lagoon and Eastern f
Areas may require remediation. Table 9-1-fS-2t presents a summary of the areas with the
corresponding existing maximum constituent concentrations, RBTCLs, ARARs and soil target
clean-up levels for protection of ground water evaluated in detail in Appendix G. ( The RBTGbs
pFOseRted SR this tal31e were deFived !SF peteRlial humaR FesepteFS at tho 1 x 10·5 Fisk level aRd
usiRg the alternate degradatieR rates dissussed iR SestieR 9.1.1.2. These alternate degradatieR
Fates (1 year fer peRlaohlerepheRel iR surfase seil, e years fer peRtashlerepheRel iR sul3surfaoe
seil, aRd 12 years fer PGDD/PGDF) are 13elie·,ed ts mest assurately represeRt seRservative
estimates el degradatieR el oeRstitueRts.]
Table 9-1-fS-2t also shows the clean-up goals recommended by Beazer East, Inc. for the various
media identified here. For surface and subsurface soil in Area C, the recommended clean-up
goals are the soil target clean-up levels for the protection of ground water. For Fire Pond surface
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water and fish, the recommended clean-up goals are the human health RBTCLs at the 1E-05 risk I
level derived in Appendix G. For ground water, the recommended clean-up goals are the federal
ARARs, or MCLs.
The recommended soil clean-up goals at this Site are the soil target clean-up levels for the
protection of ground water: 95 ppm for pentachlorophenol, and 0.007 ppm for PCDD/PCDF.
Upon review of the available surface soil data in Area C, it is apparent that remediation of
pentachlorophenol to it's clean-up goal for the protection of ground water will also achieve the
1
clean-up goal for PCDD/PCDF. This is illustrated in Table 9-2-f9-at. The measured
pentachlorophenol concentrations in Area C surface soil are ranked in descending order and are
compared with the pentachlorophenol soil target clean-up level for the protection of ground
water. Four samples in this area exceed the soil target clean-up level for the protection of
ground water. Based upon the historical operations of the Koppers facility on the Site, it is likely
that the occurrence and concentration of pentachlorophenol and PCDD/PCDF in surface soils
are co-located. This co-location of constituents is shown on Table 9-2-f9-at. Therefore, when
these four areas are remediated, the samples with concentrations in excess of the PCDD/PCDF
soil target clean-up level for the protection of ground water are also remediated. This I
remediation strategy will be investigated further in the pre-design activities for the Remedial
Design Scope of Work.
I
As a result of this analysis, it is apparent that treating the remediation of pentachlorophenol and
PCDD/PCDF separately is unnecessary. Focussing the remediation strategy on remediating
soils in Area C such that 95 ppm is not exceeded for pentachlorophenol, will also result in
achievement of the [RBTGL and the) soil target clean-up level for the protection of ground water I
for PCDD/PCDF.
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DRAFT
.. -.. -TABLE 9-1 -REVISED
SUMMARY OF REMEDIAL GOALS
CLEAN-UP LEVELS EVALUATION
FORMER KOPPERS COMPANY, INC. SITE
BEAZER EAST, INC., MORRISVILLE, NC
Commercial/Industrial Sito Use
Medium / Area Constituent
Surface Soil / Aree. C Pentachlorophenol
PCDD/PCOF
Pentachlorophenol
Subsurface Soil / Area C PCOD/PCDF
Fish / Fire Pond PCDD/PCOF
Resldantlal Site Use
Surface Soil / Area C Penlachlorophenol
PCDD/PCDF
Pentachlorophenol
Subsurface Soil / Area C PCDD/PCDF
Sur:ac~ Wat~r / Fire Pond PCDD/PCDF
Fish/ Fire Pond PCDD/PCDF
Ground Water/ Pentachlorophenol
FQf"mel" lagoon Area PCDD/PCDF
Ground Water/ PenrachlOf"ophenol
Eastern Area PCDD/PCDF
Notes:
.. ..
Existing Maximum
Concentration (ppm)
3220
0.3
560
0.004
4E-05
3220
0.3
560
0.004
3E--07
4E--05
1.5
BE-08
0.05
2E--07
ARAR -Applicable and Relevant or Appropriate Requirement.
MCL • Maximum Contaminant level.
RBTCL • Risk-Based Target Clean-up Level.
-
Human H-lth
RBTCL at the 1 E-04
Risk Lovol (a) (ppm)
3000
0.006
9000
0.2
2E-04
200
5E-04
20000
0.04
2E-07
SE-05
0.04
3E-08
0.04
3E-08
(a) -Human Hoolth RBTCls were derived !or each risk level, assuming degradation does not occur.
Soil RBTCLs !or Commercial/Industrial Site use are for on-Site wor1<ers.
(b) -ARARs for PCDD/PCDF are derived for 2,3,7,8-TCDD.
(c) • The MCL for 2,3,7,8-TCDD is a proposed MCL.
- -Does not apply.
SUMMARY9.WQ1 R.N.: 8 18-Jun-92
-
Human Health
RBTCL at tho 1E-05
Risk Lovol (a) (ppm)
300
BE-04
900
0.02
2E-05
20
SE-OS
2000
0.004
2E-oa
SE-06
0.004
3E-09
0.004
3E-09
-.. .. ..
Human Health Soll Target Lovol North carollna Federal ARAR Beamr East, Inc.
RBTCL at tho 1E•06 for tho Protec:Uon of ARAR (MCL) Recommondod
Risk Level (a) (ppm) Ground Water (ppm) (b) (ppm) (b)(c) (ppm) Clean-up Goal (ppm)
30 95 --95
6E-05 0.007 --0.007
90 95 95
0.002 0.007 0.007
2E-06 ---2E-05
2 95 --95
5E-06 0.007 --0.007
200 95 95
4E-04 0.007 ----0 007
2E-09 ------2E-08
SE-07 -----SE-06
4E-04 ---0.001 0.001
3E-10 2E-10 5E-08 SE-08
4E-04 --0.001 0.001
3E-10 --2E-10 5E-08 SE--Oa
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EN3l
APPENDIX E
ADDITIONAL EXPOSURE ASSESSMENT INFORMATION
The baseline risk assessment process as mandated by U.S. EPA requires the creation of
exposure scenarios to assess the potential for adverse health impacts from Site related
constituents of potential interest. While these scenarios represent hypothetical people and
activities, they are intended to reflect the actual physical description of the Site and surrounding
industrial, residential, and recreational areas, as well as activities that typically occur in these
areas. Both current and future potential exposures are evaluated for the Morrisville Site and are
described in Section 4.0 of the baseline risk assessment.
The potential receptors identified in the baseline risk assessment include:
1. current and future local resident (this receptor includes the evaluation of a potential on-
Site trespasser),
2. current and future on-Site worker,
3. future construction worker, and
4. future hypothetical on-Site resident.
The potential pathways and potential exposure media are listed in Table E-1 . The concentrations
of constituents used as potential exposure point concentrations in the estimation of potential
exposure dose are presented in Tables 2-4 through 2-12 (2 11] in Section 2.0 of the baseline
risk assessment. Exposure point concentrations used in the estimation of potential exposure
dose represent either the upper 95th percent confidence intervals on arithmetic mean
concentrations or the maximum reported concentration of constituents in the various media. Per
EPA Region IV Guidance (U.S. EPA, 1991), maximum values were used when the upper 95th
percent confidence interval concentration exceeds the maximum value.
(To evaluate potential el(posures from surlaoe soil, sul:lsurlaoe soil, and sediment,] In the first
draft of the baseline risk assessment, degradation factors for the phenolic compounds and
PCDD /PCDFs were applied to reported Constituent concentrations to evaluate potential
exposures from surface soil, subsurface soil, and sediment. The degradation factors were
derived from a review of the scientific literature (and are disoussed in Seotion 4.0.) Table E-2
presents the degradation factors for phenolics and dioxin for the potential exposure durations
evaluated in the baseline risk assessment.
A:\PUBS\PROJECTS\0845008\000.APE E-1
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TABLE E-2
DEGRADATION FACTORS USED TO CALCULATE BASELINE RlSKS
HUMAN HEALTH EVALUATION
FORMER KOPPERS INC. SITE
BEAZER EAST INC., MORRJSVILLE, NC
CONSTITUENT DEGRADATION FACTOR(# YEARS) !f',):C){/''""
Phenolics• 0.030 (8 years -Trespasser Evaluation)
0.013 (18 years -Local Resident Evaluation)
0.012 (20 years -On-Site Worker Eveluation)
0.008 (30 years -Hypothetical On-Site Resident Evaluation)
Total TCDD-TE" 0.80 (8 years -Trespasser Evaluation)
0.62 (18 years -Local Resident Evaluation)
0.59 (20 years -On-Site Worker Evaluation)
0.48 (30 years -Hypothetical On-Site Resident Evaluation)
Notes:
• -Degradation factor for pentachlorophenol.
•• -Degradation factor for 2,3,7,8-TCDD.
TABLE_E2.WKI
RN: 3
18-Jun-92
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The following equation was used to calculate degradation constants:
Where:
And:
>.. =0.693/t112
Average Concentration at t,
(Where t, = 8 years, 20 years, or 30 years)
(Where penta 1112 = 0.167 years for calculation of
baseline risks and clean-up levels, and o. 167 or
1.0 years for calculation of clean up levels; and
TCDD 1112 = 12 years)
As stated in the Risk Assessment Guidance for Superfund (U.S. EPA, 1989), the environmental
fate and transport of chemicals, including degradation, is an important consideration at
Superfund sites. It is therefore logical to include degradation in the calculation of risks and
clean-up levels, particularly since degradation in the ambient environment has been documented
to occur. However, EPA Recion N has requested that degradation be removed from all
calculations in the text of the baseline risk assessment, although they have agreed that
degradation can be included in the appendicies. EPA Region N has not approved the use of
degradation factors because there are no site-specific data available to support the particular
factors used to evaluate exposure at this Site. However, it should be noted that if any are used,
EPA prefers that a half-life (tw) of 1 year be used for pentachlorphenol.
In this document, spreadsheets calculating potential exposure and assumed risk, including
degradation factors, are located in Appendix E-4. Alternate calculations that do not include
degradation factors are also included in Appendix E-4, and are ummarized in Section 5.
Similarly, clean-up levels are calculated in Appendix G, both with and without degradation
factors. Clean-up levels calculated without degradation factors are summarized in Section 9.
The calculations in Appendix E-4 assume a half-life of 60 days for pentachlorophenol. If the
alternate half-life for pentachlorophenol derived in the more detailed literature search presented
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in Appendix G (1 year) had been used, the risks would have been somewhat higher than those
based on a 60 day half-life, and considerably lower than those based on no degradation.
Table E-3 demonstrates the effect of degradation (assuming a half-life of 60 days for pen-
tachlorophenol and 12 years for dioxin) on both dioxin and pentachlorophenol risks in all soil and
sediment evaluated in the baseline risk assessment. Surface soil in Area C had the highest
potential assumed risks for the Site for eve,y receptor evaluated in the baseline risk assessment.
As shown in Table E-3, if degradation is not included, potential assumed risks from pen-
tachlorophenol for all receptors in all media, increase approximately one to two orders of
magnitude for the receptors with potential long term exposures. Potential assumed risks from
dioxin increase approximately two times for receptors with potential long term exposures.
Removal of degradation does result in an increase in potential assumed risks from pen-
tachloropheno/ for local resident trespassers, on-Site workers and hypothetical on-Site residents,
yet it does not substantially alter the overall estimates of total assumed risk for these receptors
because most of the potential assumed risk at the Site is attributable to dioxin.
Therefore, the application of degradation factors in this baseline risk assessment does not
substantially alter the total estimated potential assumed risks from the Site. Removal of
degradation from this assessment also has little effect on selection of the areas of the Site that
potentially would require remediation.
In the baseline risk assessment, only phenolic compounds and PCDDs/PCDFs were assumed
to degrade in soils and sediment. lsopropyl ether in soils and sediment, and all constituents in
ground water, surface water and fish were not evaluated for degradation due to a lack of
constituent-specific or environment-specific data. The absence of degradation factors for all
constituents in all media leads to uncertainty in the exposure assessment.
Uncertainty is also associated with the degradation factors used in the baseline risk assessment
since the factors used assume that all loss occurs through biodegradation. As Appendix E-1
describes, other known loss mechanisms may be potentially significant for certain constituents
in certain media. In addition, the degradation factor taken from the literature for pen-
tachlorophenol was used for all phenolic compounds. Phenolic compound-specific factors
would result in different estimates of exposure point concentrations for the phenolics evaluated
in the baseline risk assessment.
There is also uncertainty associated with the specific degradation factors used in the baseline
risk assessment because the rate of degradation of any constituent is specific to the particular
environmental and microbial conditions of the medium.
R:\PUBS\PAOJECTS\0845008\CXX).APE E-5
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The assumed time of exposure is also a factor which leads to uncertainty in the use of
degradation factors in the baseline risk assessment. All phenolics and TCDD-TEs in soils and
sediment were degraded for the receptor-specific exposure duration assumed in the baseline
risk assessment for both potential current and future exposures. This will result in the
overestimation of potential future exposures because although the degradation factor accounts
for the degradation that is expected to occur over the duration of the potential exposure, the
degradation that occurs from the time of sampling to the time the exposure is assumed to begin
has not been accounted for in this assessment. If this time had been accounted for, the
exposure point concentrations used in the future assessment(s) would have been lower. As a
result, the potential assumed risks estimated for the future soil and sediment scenarios would
have been lower than reported in the baseline risk assessment.
Surface and subsurface soils were assumed to be inhaled as dust particles during certain
potential on-Site exposures. Dust in air concentrations were derived by multiplying the annual
average PM10 value for the Raleigh-Durham, North Carolina area (reported value = 0.0334
mg/m3
) by the potential exposure point concentration for each phenolic compound and dioxin.
This appendix contains several subappendices that provide additional exposure information for
this evaluation. Appendix E-1 reviews the chemical and environmental factors that control the
fate and transport of constituents of potential interest at the Site.
Appendices E-2 and E-3 include detailed discussions of the models used to evaluate potential
exposures due to vegetable ingestion and contact with constituents in ground water during
showering, respectively. These appendices also contain spreadsheets used to generate potential
risks from vegetable ingestion and showering. Appendix E-4 contains the formulas and
calculations (spreadsheets) used to calculate potential exposure dose and potential assumed
risk for all potential human exposure pathways except the showering and vegetable pathways.
R:\PUBS\PROJECTS\0845008\000.APE E-6
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DRAFT
ATTACHMENT 9
----liill -------TABLE E-4-la
LOCAL OFF-SITE RESIDENT-SURFACE SOIL
POTENTIAL CARCINOGENIC RISK -SCALING TABLE•
IIUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC SITE
BEAZER EAST INC., MORRISVILLE, NC
SURFACE SOIL-AREA A
lkgraded Nondegraded
Cone. Degraded Cone. Nondcgraded
CONSTITIJENT (mµ'kg) Risk (mF,fkg) Risk
PHENOL 2.J6E-03 NC 7.83E-02 NC
2-CHLOROPHENOL ND NC ND NC
2-NITROPHENOL UIE-03 NC 4.36E-02 NC
2,4-DIMEIBYLPHENOL l.82E--03 NC 6.0SE-02 NC
2.4-DICHLOROPHENOL ND NC ND NC
4-CHLORO-3-MErnYLPHENOL ND NC ND NC
2,4,6-TRICHLOROPHENOL 3.26E-03 5.64E-13 l.0SE-01 1.87E-11
2.4-DINITROPHENOL 3.32E-03 NC 1.J0E-01 NC
4-NITROPHENOL 4.17E-03 NC l.39E-Ol NC
23.5,6-TETRACIILOROPHENOL ND NC ND NC
2-METIIYL-4,6,-DINITROPHENOL ND NC ND NC
PENTACHLOROPHENOL ND NC ND NC
ISOPROPYL ETI--IER ND NC ND NC
TOT AL TC OD-TE NA NC NA NC
TOTAL 5.64E-13 1.87E-11
Notes:
SURFACE SOIL -AREA B
Degraded Nondegraded Degraded
Cone. Degraded Cooc Nondegraded Cone.
(mg/kg) Risk (mg/kg) Risk (mg:/kg)
ND NC ND NC ND
3.04E-03 NC 1.0IE-01 NC 3.77E-03
ND NC ND NC ND
ND NC ND NC 4.0lE-03
ND NC ND NC 2.89E-03
ND NC ND NC 3.57E-03
ND NC ND NC 2.39E-03
ND NC ND NC 4A4E-02
ND NC ND NC ND
ND NC ND NC 3.60E-02
ND NC ND NC UlE-03
4.9JE-03 9.27E-12 1.63E-01 3.0SE-10 2A4E+Ol
ND NC ND NC ND
1.03E-04 9.72E-08 1.28E-04 1.2IE-07 1.64E-Ol
9.72E-08 l.22E-07
• -Phenolic compounds and pentach!orophenol were assumed to have a half-life of 60 days; dioxin was assumed to have a half-life of 12 years. (See ten).
SURFACE SOIL-AREA cu
Nondegraded
Degraded Cooc Nondegraded
Risk (mg/kg) Risk
NC ND NC
NC 1.25E-Ol NC
NC ND NC
NC 1.33E-Ol NC
NC 9.6lE-02 NC
NC 1.lSE-01 NC
1.65E-12 7.93E-02 5A9E-11
NC 1A7E+OO NC
NC ND NC
NC 1.19E+OO NC
NC 1.56E-Ol NC
1.84E-07 8.10E+02 6.12E-06
NC ND NC
6.18E-04 2.04E-01 7.72E-04
6.lSE-04 7.78E-04
•• -Phenol, 2-nitrophenol, and 4-nitrophenol were not detected in Area C surface soils; as such, risks or hazard Indices for these constituents are not displayed here or in Section 5 summary tables.
E,qxnure spreadsheets, also presented in Appendix E-4, calculate risks and haz.ard indices for these constituents, using one-half the sample quantitation limit for each constituent as its soil concentration.
NA -Not Analyzed.
NC. Not Calculated.
ND • Not Detected.
Filename: LRSSC.WQI
RN:03
05-May-92
SURFACE SOIL -AREA D
Degraded Nondegraded
Cone. Degraded Cone. Nondegraded
(mµkg) Risk (mg:/kg) Risk
ND NC ND NC
ND NC ND NC
ND NC ND NC
2.08E-02 NC 6.89E-Ol NC
ND NC ND NC
ND NC ND NC
9.04E-03 1.56E-12 3.00E-01 5.19E-11
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
NA NC NA NC
1.56E-12 5.19E-11
.. 11111
TABLE E-4-1 b
LOCAL OFF-SITE RESlDENT-SURFACE SOIL
POTENTIAL NONCARCINOGENIC RISK -SCALING TABLE•
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE. NC
SURFACE SOIL· AREA A
Degraded Nondegraded
Cone. Degraded Cone. Nondcgraded
CONSTITUENT (mF.fkg) Risk (mRfkg) Risk
PHENOL 2.36E-03 OJE-10 7.83E-02 1.44E-08
2-CHLOROPHENOL ND NC ND NC
2-NITROPIIENOL 1.3 lE-03 1.81E-08 4.36E-02 6.0IE-07
2,4-DIMETHYLPHENOL 1.82E-03 1.00E-08 6.05E-02 3.33E-07
2.4-DICHLOROPIIENOL ND NC ND NC
4-CIILOR0-3-METHYLPHENOL ND NC ND NC
2.4,6-TRICHLOROPHENOL 3.26E-03 NC 1.0SE-01 NC
2.4-DINITROPIIENOL 3.32E-03 1.83E-07 1.lOE-01 6.0SE-06
4-NITROPHENOL 4.17E-03 5.75E-08 1.39E-01 1.91E-06
2.3.5.6-TETRACHLOROPHENOL ND NC ND NC
2-METI-IYL-4.6.-DINITROPIIENOL ND NC ND NC
PENTACHLOROPHENOL ND NC ND NC
ISOPROPYL ETHER ND NC ND NC
TOTAL TCDD-TE NA NC NA NC
TOTAL 2.69E-07 8.94E-06
Notes:
SURFACE SOIL-AREA B
Degraded Nondegraded Degraded
Cone Degraded Cone. Nondegraded Cone.
(m'11<,l Risk (m'11<,l Risk (mg/kg)
ND NC ND NC ND
3.04E-03 6.70E-08 1.0IE-01 2.23E-06 3.77E-03
ND NC ND NC ND
ND NC ND NC 4.0lE-03
ND NC ND NC 2.89E-03
ND NC ND NC 3.57E-03
ND NC ND NC 2.39£-03
ND NC ND NC 4.44E-02
ND NC ND NC ND
ND NC ND NC 3.60E-02
ND NC ND NC UIE-03
4.91E-03 1.SOE-08 1.63E-Ol 5.99E-07 2.44E+Ot
ND NC ND NC ND
1.03E-04 NC 1.28E-04 O.OOE+OO 1.64E-01
8.SIE-08 2.82E-06
• -Phenolic comp:Junds and pentachlorophenol were assumed to have a half-life of 60 days: dioxin was assumed to have a half-life of 12 years. (See text).
SURFACE SOIL. AREA cu
Nondcgraded
Degraded Cone. Nondcgraded
Risk (m'11<,l Risk
NC ND NC
3.32E-07 1.25E-Ol 1.l0E-05
NC ND NC
8.84E-08 1.33E-01 2.93E-06
4.25E-07 9.61E-02 1.41E-05
7.86E-08 1.18E-01 2.61E-06
NC 7.93E-02 NC
9.79E-06 1.47E+OO 3.25E-04
NC ND NC
l.59E-06 l.l9E+OO 5.26E-05
1.04E-06 1.56E-01 3.44E-05
3.58E-04 8.10E+02 1.19E-02
NC ND NC
NC 2.04E-Ol NC
3.72E-04 l.23E-02
••·Phenol. 2-nitrophenol, and 4-nitrophenol were not detected in Area C surface soils; as such, risks or hazard indices for these constituents are not displayed here or in Section 5 summary tables.
Exp:Jsure spreadsheets, also presented in Appendix E-4, calculate risks and hazard indices for these constituents. using one-half the sample quantilation limit for each constituent as its soil concentration.
NA· Not Analyi.cd.
NC • Not Calculated.
ND • Not Detected.
Filename: LRSSNC.WQt
RN:03
05-May-92
SURFACE SOIL-AREA D
Degraded Nondegraded
Cone Degraded Cone Nondegraded
(mg/kg) Risk (mg/kg) Risk
ND NC ND NC
ND NC ND NC
ND NC ND NC
2.0SE-02 1.14E-07 6.89E-01 3.SOE-06
ND NC ND NC
ND NC ND NC
9.04E-03 NC 3.00E-01 NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
NA NC NA NC
1.14E-07 3.SOE-06
TABLE E-4-2a
LOCAL OFF-SITE RESIDENT· SUBSURFACE SOIL
POTENTIAL CARCINOGENIC RISK -SCALING TABLE'
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
SUBSURFACE SOIL -AREA C
Degraded Nondegraded
Cone. Degraded Cone.
CONSTITUENT (mg/kg) Risk (mg/kg)
PHENOL ND NC ND
2-CIILOROPHENOL t.18£--02, NC 3.92£-01
2-NITROPHENOL 2.19£-03 NC 7.28£-02
2.4-DIMEll-IYLPHENOL 5.19£-03 NC I. 72£--01
2.4-DICIILOROPIIENOL 7.12£--03 NC 2.36£-01
4-CIILORO-3-METI-IYLPHENOL 1.84£--03 NC 6.12£-02
2,4,6-TRICIILOROPIIENOL 5.0IE-03 3.74£-13 1.66£-01
2,4-DINITROPHENOL J.65£--03 NC 5.48£--02
4-NITROPIIENOL 3.86£--03 NC 1.28£-01
2.3.5.6-TETRACHLOROPHENOL 7.64£-03 NC 2.54£-01
2-MElllYL-4,6,-DINITROPHENOL ND NC ND
PENTACIILOROPHENOL l.42E+OO 1.15E--09 4.70£+01
ISOPROPYL ETI-IER 6.21£-01 NC 6.ZIE--01
TOTAL TCDD-TE ].23£-03 5.00E--07 1.54£-03
TOTAL 5.02£--07
Notes:
••Phenolic compounds and pentachlorophenol were assumed to have a half.life or 60 days;
dioxin was assumed to have a half.life of 12 years. (See text).
NC· Not Calculated.
ND -Not Detected.
File Name: LRSBC. WQt
RN:02
22.Jun.92
Nondegraded
Risk
NC
NC
NC
NC
NC
NC
1.24£-11
NC
NC
NC
NC
3.BJE--08
NC
6.25E--07
6.63£-07
.. 11111
TABLE E-4-2b
LOCAL OFF-SITE RESIDENT -SUBSURFACE SOIL
POTENTIAL NONCARCINOGENIC RISK -SCALING TABLE*
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC.. MORRISVILLE, NC
SUBSURFACE SOIL -AREA C
Degraded Non degraded
Cone. Degraded Cone.
CONSTITUENT (mglkgi Risk (mg/kg)
PHENOL ND NC ND
2-CHLOROPIIENOL 1.18E-02 J.t2E-06 3.92E-01
2-NITROPHENOL 2.19£-03 t.J0E-07 7.28E-02
2.4-DIMETI-IYLPIIENOL 5.19E-03 1.23E-07 l.72E.Ot
2.4-D ICI ILO ROPI IENO L 7.12E-03 t.13E-06 2.36E-Ol
4-CHLORO-3-METIIYLPHENOL 1.84E-03 4.38E-08 6.IZE-02
2.4.6-TRICHLOROPHENOL 5.0lE-03 NC l.66E-Ol
2,4-DINITROPIIENOL 1.65E-03 3.92E-07 5.48E--02
4-NITROPHENOL 3.86E-03 2.29E-07 l.28E-Ol
2.3,5,6-TETRACIILOROPHENOL 7.64E-03 3.63E-07 2.54£-01
2-METIIYL-4,6,-DINITROPHENOL ND NC ND
PENTACHLOROPHENOL t.42E+OO 2.2-'E-05 4.70E+0l
ISOPROPYL ETHER 6.21E-01 1.47E-06 6.21E-Ol
TOTAL TCDD-TE 1.23E-03 NC 1.54E-03
TOTAL 2.74E-05
Notes:
• -Phenolic compounds and pentachlorophenol were assumed to have a half-life of 60 day~
dioxin was assumed to have a half-life of 12 years. (Sec text).
NC· Not Calculated.
ND -Not Detected.
File Name: LRSBNC.WQl
RN:02
22-Jun-92
Non degraded
Risk
NC
3.72E-05
4.32E-06
4.09E-06
3.74E-05
1.45E-06
NC
1.J0E-05
7.60E-06
1.Z0E-05
NC
7.44E-04
1.47E-06
NC
8.62E-04
-----
-iliil -TABLE E-4-3a
LOCAL OFF-SITE RESIDENT -SEDIMENT
POTENiIAL CARCINOGENIC RISK -SCALING TABLE*
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
SEDIMENT· FIRE POND
Degraded Nondegradec
Cone. Degraded Cone.
CONSTrnJENT (mg/kg) Risk (mg/kgj
PHENOL 3.28E-03 NC l.09E-Ol
2-CHLOROPHENOL 6.0IE-03 NC 2.00E-01
2-NITROPHENOL J.49E-03 NC 4.9-IE--02
2.4-DIMETHYLPHENOL 2.0JE-03 NC 6.73E-02
2,4-DICHLOROPHENOL ND NC ND
4-CHLORO-3-METIIYLPHENOL ND NC ND
2,4,6-TRICHLOROPIIENOL ND NC ND
2,4-DINITROPHENOL ND NC ND
4-NITROPHENOL 5.69E-03 NC 1.89E--01
2,3,5,6-TETRACHLOROPIIENOL ND NC ND
2-METHYL-4,6,-DINITROPHENOL 3.l7E-03 NC l.0SE-01
PENTACIILOROPHENOL 3.40E-02 2.30E-1 l 1.13E+OO
ISOPROPYL ETIIER ND NC ND
TOTAL TCDD-TE 3.58E-04 1.21E--07 4.47E-04
TOTAL 1.21E--07
Notes:
.. --
SEDIMENT -MEDLIN POND
Degraded Non degrade<
Nondegraded Cone. Degraded Cone. Nondegraded
Risk (mg/kgj Risk (mg/kgj Risk
NC 3.61E-03 NC 1.20E-Ol NC
NC ND NC ND NC
NC ND NC ND NC
NC 4.73£--02 NC 1.57E+OO NC
NC ND NC ND NC
NC ND NC ND NC
NC ND NC ND NC
NC ND NC ND NC
NC ND NC ND NC
NC ND NC ND NC
NC ND NC ND NC
7.6SE-10 ND NC ND NC
NC ND NC ND NC
1.51E-07 8.09E--04 2.74E-07 1.0lE-03 3.42E--07
1.S2E-07 2.74E-07 3.42E-07
• -Phenolic compounds and pentachlorophenol were assumed to have a half-life of 60 days;, dioxin was assumed to have a half-life of 12 years. (See text).
NC -Not Calculated.
ND -Not Detected.
File Name: LRSDC.WQI
RN,02
22-Jun-92
SEDIMENT-FIRE POND DISCHARGE STREAM
Degraded NondegradeC
Cone. Degraded Cone. Non degraded
(mg/kg) Risk (mg/kgj Risk
8.43£--04 NC 6.J0E-02 NC
ND NC ND NC
6.lOE-CM NC 4 . .56E--02 NC
1.-1-IE-03 NC 1.07E-01 NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
t.20E-03 NC 8.96E-02 NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
1.46E-02 1.96E-to 1.09E+OO l.47E-08
ND NC ND NC
6.58E--04 4.42E-06 1.06E-03 7.toE--06
4.42E-06 7.12E-06
lilil
TABLE E-4-3b
LOCAL OFF-SITE RESIDENT-SEDIMENT
POTENTIAL NONCARCINOGENIC RISK -SCALING TABLE*
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
SEDIMENT· FIRE POND
Degraded Nondegradei
Cone. Degraded Cone.
CONSTITUENT (mg/kg) Risk (mg/kgj
PHENOL 3.28E-03 2.16E-IO 1.09E-01
2-CIILOROPHENOL 6.0IE-03 4.75E-08 2.00E--01
2-NITROPIIENOL 1.49E-03 7.35E--09 4.94E-02
2.4-DIMElllYLPHENOL 2.0JE-03 4.0IE--09 6.73£--02
2,4-DlCIILOROPHENOL ND NC ND
4-CJILORO-3-METIIYLPHENOL ND NC ND
2,4,6-TRICIILOROPIIENOL ND NC ND
2.4-DlNITROPHENOL ND NC ND
4-NITROPIIENOL 5.69E-03 2.8IE.08 l.89E-01
2,3.5,6-TETRACIILOROPHENOL ND NC ND
2-METIIYL-4.6.-DINITROPHENOL 3.l?E-03 6.27E-08 1.05E-Ot
PENTACIILOROPHENOL 3.40£-02 4.48£-08 1.13E+OO
ISOPROPYL ETI-IER ND NC ND
TOTAL TCDD-TE 3.58E-04 NC 4.47£-04
TOTAL l.95E-07
Notes:
..
SEDIMENT -MEDLIN POND
Degraded Nondegradec
Non degraded Cone. Degraded Cone. Nondegraded
Risk (mg/kgj Risk (mg/kgj Risk
7.18E--09 3.61E-03 2.38E-10 l.20E-01 7.91E--09
J.58E-06 ND NC ND NC
2.44E-07 ND NC ND NC
1.33£-07 4.73£--02 9.34£-08 1.57E+OO 3.IOE-06
NC ND NC ND NC
NC ND NC ND NC
NC ND NC ND NC
NC ND NC ND NC
9.34E-07 ND NC ND NC
NC ND NC ND NC
2.08E-06 ND NC ND NC
1.49£-06 ND NC ND NC
NC ND NC ND NC
NC 8.09E-04 NC 1.0lE-03 NC
6.46E-06 9 . .J6E-08 3.llE-06
• -Phenolic compounds and pentachlorophenol were assumed to have a half-life of 60 days;. dioxin was assumed to have a half-life of 12 years. (See tenj.
NC-Not Calculated.
ND -Not Detected.
File Name: LRSDNC: WQl
RN:02
22-Jun-92
SEDIMENT -FIRE POND DISCHARGE STREAM
Degraded Nondegradec
Cone. Degraded Cone. Non degraded
(mg/kg) Risk (mg/kg) Risk
8.43E-04 6.47E-10 6.J0E-02 4.83E-08
ND NC ND NC
6.I0E-04 3.51£--08 4.56E-02 2.62E--06
1.44£--03 3.3!E-08 l.07E-01 2.47E-06
ND NC ND NC
ND NC ND NC
ND NC ND NC
t.20E-03 2.76E.07 8.96E-02 2.06E-05
ND NC ND NC
ND NC ND NC
ND NC ND NC
1.46E-02 2.25E.07 t.09E+OO !.68E-05
ND NC ND NC
6.58E-04 NC 1.06£-03 NC
5.69E.07 4.25E-05
TABLE E-4-4a
ON-SlTE WORKER -SURFACE SOIL
POTENTIAL CARCINOGENIC RISK -SCAUNG TABLE•
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EASf INC., MORRISVILLE. NC
SURFACE SOIL. AREA A
Degraded Nondcgraded
Cone. Degraded Cone. Nondegraded
CONSTITIJE;-...'T (mg/kg) Risk (mg/kg) Risk
PHENOL 9.43E-04 NC 7.83E-02 NC
2-CIILOROPHENOL ND NC ND NC
2-NITROPHENOL 5.26E-04 NC 4.36E-02 NC
2.4-DIMETHYLPHENOL 7.29E-04 NC 6.0SE-02 NC
2.4-DICIILOROPHENOL ND NC ND NC
-t-CIILORO-3-METI-IYLPHENOL ND NC ND NC
2.4.6-TRICIILOROPHENOL l.30E-03 4.08E-12 t.0BE-01 3.38E-10
2.4-DINITROPHENOL l.33E-03 NC 1.l0E-01 NC
4-NITROPHENOL 1.67E-03 NC l.39E-01 NC
2.3,."i,6-TETRACHLOROPIIENOL ND NC ND NC
2-METHYL-4,6,-DINITROPHENOL ND NC ND NC
PENTACHLOROPHENOL ND NC ND NC
ISOPROP't'L ETHER ND NC ND NC
TOTAL TCDD-TE NA NC NA NC
TOTAL 4.0BE-12 3.JBE-10
Notes:
.. .. 11111
SURFACE SOIL· AREA B
Degraded Nondegraded Dc:graded
Cone. Degraded Cone. Nondegraded Cone.
(mg/kJI:) Risk (mg/kg) Risk (mg/kg)
ND NC ND NC ND
1.22E-03 NC l.OIE-01 NC 1.51E-03
ND NC ND NC ND
ND NC ND NC l.60E-03
ND NC ND NC 1.16E-03
ND NC ND NC 1.43E-03
ND NC ND NC 9.56E-04
ND NC ND NC l.78E-02
ND NC ND NC ND
ND NC ND NC 1.44E-02
ND NC ND NC LBBE-03
l.96E-03 6.70E-11 1.63E-Ol 5.56E-09 9.76E+OO
ND NC ND NC ND
7.62E-05 1.J0E-06 l.28E-04 2.19E-06 1.21E-Ol
1.30E-06 2.20E-06
• -Phenolic comp::,unds and pc:ntachlorophenol were assumed to have a half-life of 60 da~; dioxin was assumed to have a half-life or 12 years. (See telrt).
SURFACE SOIL -AREA C ..
Nondegraded
Degraded Cone. Nondl:'gradc:d
Risk (mg/kg) Risk
NC ND NC
NC 1.25E-01 NC
NC ND NC
NC 1.33E-01 NC
NC 9.61E-02 NC
NC 1.18E-01 NC
2.99E-12 7.93E-02 2.48E-10
NC 1.47E+OO NC
NC ND NC
NC l.19E+OO NC
NC l.56E-Ol NC
3.33E-07 8.JOE+02 2.76E-05
NC ND NC
2.07E-03 2.04E-Ol 3.49E-03
2.07E-03 3.52E-03
•• -Phenol, 2-nitrophcnol, and 4-nilrophenol \\'ere not detected in Arca C surface soils: as such. risks or hazard indices for these constituents are not displayed here or in Section 5 summary tables.
Exp::,sure spreadsheets, also presented in Appendix E-4, calculate risks and hazard indices for these constituents, using one-half the sample quantitation limit for each constituent as its soil concentration.
NA -Not Analyzed.
NC -Not Calculated
ND -Not Detected
Filename: OWSSC. WQl
RN:03
22-Jun-92
SURFACE SOIL· AREA D
Degraded Nondegraded
Cone. Degraded Cone. Nondegraded
(mg/kg) Risk (mg/kg) Risk
ND NC ND NC
ND NC ND NC
ND NC ND NC
8.30E-03 NC 6.B9E-01 NC
ND NC ND NC
ND NC ND NC
3.61E-03 1.13E-l 1 3.00E-01 9.39E-10
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
NA NC NA NC
1.13E-11 9.39E-10
--TABLE E--t--tb
ON-SITE WORKER-SURFACE SOIL
POTENTIAL NONCARCINOGENIC RISK -SCALING TABLE•
HUMAN IIEALTII EVALUATION
FORMER KOPPERS COMPANY INC SITE
BEAZER EAST INC., MORRISVILLE. NC
SURFACE SOIL-AREA A
Degraded Nondegraded
Cone. Degraded Cone. Nondegradcd
CONSTITIJENT (mg/kg) Risk (mg/kg) Risk
PHENOL 9.43E-04 1.57E-09 7.83E-02 1.30E-07
2-CIILOROPHENOL ND NC ND NC
2-NITROPIIENOL S.26E-04 6.54E-08 4.36E-02 S.43E-06
2.4-DIMETI{YLPHENOL 7.29E-04 3.63E.08 6.05E.02 3.0lE.06
2,4-DICIILOROPHENOL ND NC ND NC
4-CllLORO-3-METIIYLPHENOL ND NC ND NC
2,4,6-TRICIILOROPHENOL 1.30E-03 NC 1.08E-Ot NC
2.4-DINITROPIIENOL Ll3E-03 6.62E-07 1.l0E.01 5.50E-05
4-NITROPHENOL 1.67E-03 2.08E.07 1.39E-01 1.72E-05
2.3.5.6-TETRACIILOROPHENOL ND NC ND NC
2-METI--IYL-4,6,-DINITROPHENOL ND NC ND NC
PENTACHLOROPHENOL ND NC ND NC
ISOPROPYL ETIIER ND NC ND NC
TOTAL TCDD-'IB NA NC NA NC
TOTAL 9.73E-07 8.08E-05
Notes:
-
SURFACE SOIL -AREA B
Degraded Nondegraded Degraded
Cone. Degraded Cone. Nondegradcd Cone.
(mg/kg) Risk (rnFfkg) Risk (mg/kg)
ND NC ND NC ,u
1.22E-03 2.42E-07 1.0JE-01 2.0lE-0S 1.SJE-03
ND NC ND NC ND
ND NC ND NC 1.60E.03
ND NC ND NC 1.16E-03
ND NC ND NC 1.43E.03
ND NC ND NC 9.56E-04
ND NC ND NC 1.78E-02
ND NC ND NC ND
ND NC ND NC 1.44E.02
ND NC ND NC 1.SSE-03
1.96E-03 6.52E-08 t.63E-01 5.41E-06 9.76E+OO
ND NC ND NC ND
7.62E-05 NC 1.28E-04 NC 1.21E-01
3.08E-07 2.55E-05
• -Phenolic compounds and penlachlorophenol were assumed to ha\·e a half-life of 60 days; dioxin was assumed to have a half-life of 12 years. (See text).
SURFACE SOIL -AREA c••
Nondegradcd
Degraded Cone. Nondegraded
Risk (mg/kg) Risk
NC ND NC
3.00E-07 1.2SE-01 2.49E-OS
NC ND NC
7.99E.08 1.33E.01 6.64E.06
3.8-IE-07 9.61E-02 3.18E-05
7.llE.08 1.18E-01 5.89E-06
NC 7.93E-02 NC
8.85E-06 1.47E+OO 7.34E-04
NC ND NC
1.43E-06 1.19E+OO 1.19E-04
9.38E-07 1.56E-01 7.SOE-05
3.24E-04 8.10E+02 2.69E-02
NC ND NC
NC 2.04E-01 NC
3.36E-04 2.79E-02
•• -Phenol. 2-nitrophenol, and 4-nitrophenol were not detected in Area C surface soils; as such, risks or hazard indices for these constituents are not displayed here or in Section 5 summary tables.
Exposure spreadsheets, also presented in Appendix E-4. calculate risks and hazard indices for these constituents. using one-half the sample quantitation limit for each constituent as its soil concentration.
NA -Not Analyzed
NC -Not Calculated.
ND -Not Detected.
Filename: OWSSNC.WQl
RN:03
22-Jun-92
iiiil
SURFACE SOIL-AREA D
Degraded Nondegradcd
Cone Degraded Cone Nondcgraded
(mg!k,) Risk (mg/kg) Risk
ND NC ND NC
ND NC ND NC
ND NC ND NC
8.30E.03 4.13E-07 6.89E-Ol 3.43E-05
ND NC ND NC
ND NC ND NC
3.61E-03 NC 3.00E-01 NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
NA NC NA NC
4.13E-07 3.43E-05
.. TABLE E-4-5a
ON-SITE WORKER -SUBSURFACE SOIL
POTENTIAL CARCINOGENIC RISK -SCALING TABLE•
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
liiiil liill
SUBSURFACE SOIL-AREAC
Degraded Non degraded
Cone. Degraded Cone.
CONSTITUENT (mg/kg) Risk (mg/kg)
PHENOL ND NC ND
2-CHLOROPIIENOL 4.72E-03 NC 3.92E-Ol
2-NITROPHENOL 8.78£-04 NC 7.28£-02
2.4-DIMETI-IYLPHENOL 2.08£-03 NC 1.72E-01
2.4-DICIILOROPHENOL 2.85£-03 NC 2.36£--01
4-CHLORO-3-METHYLPIIENOL 7.38E-04 NC 6.12£-02
2.4,6-TRICHLOROPHENOL 2.00E-03 3.llE-13 1.66£--01
2,4-DINITROPIIENOL 6.6IE-04 NC 5.48E-02
4-NITROPIIENOL 1.54£-03 NC 1.28£--01
2.3.5,6-TETRACHLOROPI-IENOL 3.06E-03 NC 2.54£-01
2-METHYL-4,6,-DINITROPHENOL ND NC ND
PENTACHLOROPHENOL 5.67£-01 6.59£-10 4.70£+01
ISOPROPYL ETI-IER 6.21£-01 NC 6.21E-01
TOTAL TCDD-TE 9.11£-04 5.30£-07 1.54£--03
TOTAL 5.31£-07
Notes:
••Phenolic compounds and pentachlorophenol were assumed to have a half-life of 60 days;
dioxin was assumed to have a half-life of 12 years. (See text).
NC -Not Calculated.
ND -Not Detected.
File Name: OWSBC.WQI
RN:02
22-Jun-92
Non degraded
Risk
NC
NC
NC
NC
NC
NC
2.58£-11
NC
NC
NC
NC
5.47£-08
NC
8.94£-07
9.49£-07
.. liill iiiil liiil
llll
TABLE E-4-5b
ON-SITE WORKER -SUBSURFACE SOIL
POTENTIAL NONCARCINOGENIC RISK -SCALING TABLE*
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
SUBSURFACE SOIL -AREA C
Degraded Nondegraded
Cone. Degraded Cone.
CONSTITUENT (mg/kg) Risk (mg/kg)
PHENOL ND NC ND
2-CIILOROPHENOL 4.72E-03 6.4lE--07 3.92E-01
2-NITROPllENOL 8.78E-04 7.45E-08 7.28E-02
2,4-DIMETIIYLPHENOL 2.0SE-03 7.0SE-08 l.72E--01
2,4-DICIILOROPHENOL 2.85E-03 6.45E-07 2.36E--01
4-CIILOR0-3-METIIYLPHENOL 7.JBE-04 2.S0E--08 6.tZE-02
2,4,6-TRICHLOROPHENOL 2.00E--03 NC 1.66E-01
2,4-DINITROPHENOL 6.61E--O-I 2.2-IE-07 5.48E-02
4-NITROPHENOL I.5-IE--03 t.JIE-07 l.28E-01
2.3..5.6-TETRACHLOROPIIENOL 3.06E..03 2.0SE--07 2.54E-01
2-METHYL-4,6,-DINITROPHENOL ND NC ND
PENTACHLOROPHENOL 5.67E-OI l.28E-05 4.70E+0l
ISOPROPYL ETI-IER 6.ZIE-01 2.tlE--06 6.ZtE-01
TOTAL TCDD-TE 9.1 IE-04 NC 1.54E-03
TOTAL l.70E-05
Notes:
·••Phenolic compounds and pentachloropheaol were assumed to have a half-life or 60 days;
dioxin was assumed to have a hair-lire or 12 years. (See text).
NC -Not Calculated.
ND · Not Detected.
File Name: OWSBNC.WQI
RN:02
22-Jun-92
Nondegraded
Risk
NC
5.32E-05
6.ISE-06
5.85E-06
5.35E-05
2.0SE-06
NC
l.86E-05
l.09E-05
l.72E-05
NC
l.06E-03
2.llE-06
NC
1.23E-03
lliilil -.. lilil
.. .. T AHLE E-4-6a
IIYPOlllETICAL ON-SITE RESIDENT-SURFACE SOIL
POTENTIAL CARCINOGENIC RISK-SCALING TABLE•
HUMAN HEAL TI I EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
SURFACE SOIL. AREA A
Degraded Nondegraded
C',onc. Degraded Cone. Nondcgraded
CONSTITUENT (mg/kg) Risk (mg/kg) Risk
PHENOL 6.29E-04 NC 7.83E-02 NC
2-CIILOROPHENOL ND NC ND NC
2-NITROPIIENOL 3.SOE-04 NC 4.36E-02 NC
2.4-DtMETHYLPHENOL 4.86E-04 NC 6.05E-02 NC
2.4-DICHLOROPHENOL ND NC ND NC
4-CIILORO-3-METIIYLPIIENOL ND NC ND NC
2.4.6-TRICHLOROPHENOL 8.69E-04 3.30E-11 1.08E-01 4.llE-09
2,4-DINITROPIIENOL 8.87E-04 NC l.lOE-01 NC
4-NITROPBENOL l.llE-03 NC U9E-01 NC
2.3.5,6-TETRACHLOROPIIENOL ND NC ND NC
2-METIIYL--4,6,-DINITROPHENOL ND NC ND NC
PENTACHLOROPHENOL ND NC ND NC
ISOPROPYL ETHER ND NC ND NC
TOTAL TCDD-TE NA NC NA NC
TOTAL 3.30E-11 4.1 lE-09
Notes:
Degraded
Cone.
(m,Jkg)
ND
8.1 IE-04
ND
ND
ND
ND
ND
ND
ND
ND
ND
l.31E-03
ND
6.I0E-05
liiiil -
SURFACE SOIL -AREA 8 SURFACE SOIL-AREA cu
Nondegraded Degraded Nondegradcd
Degraded Cone. Nondegradcd Cone. Degraded Cone. Nondcgradcd
Risk (mg/kg) Risk (mF-fkg) Risk (mg/kg) Risk
NC ND NC ND NC ND NC
NC 1.0IE-01 NC l.OOE-03 NC l.25E-01 NC
NC ND NC ND NC ND NC
NC ND NC 1.0?E-03 NC 1.33E-01 NC
NC ND NC 7.72E-04 NC 9.6IE-02 NC
NC ND NC 9.52E-04 NC 1.18E-01 NC
NC ND NC 6.37E-04 2.42E-l I 7.93E-02 3.0IE-09
NC ND NC 1.18E-02 NC l.47E+OO NC
NC ND NC ND NC ND NC
NC ND NC 9.59E-03 NC 1.19E+OO NC
NC ND NC 1.26E-03 NC 1.56E-01 NC
5.428.10 1.63E-01 6.7.tE-08 6.50E+OO 2.69E-06 8.10E+02 3.35E-04
NC ND NC ND NC ND NC
l.26E-05 l.28E-04 2.66E-05 9.71E-02 2.0IE-02 2.04E-01 4.23E-02
1.26E-05 2.67e-05 2.0lE-02 4.26E-02
• -Phenolic compounds and pcntachlorophenol were aHumcd lo have a ha1f-lifc of 60 days; dioxin was assumed to have a half-life of 12 years. (Sec text).
•• -Phenol, 2-nitrophcnol, and 4-nitrophcnol were not detected in Arca C surface soils: as such. risks or hazard Indices for these constituents arc not displayed here or in Section 5 summary tables.
Exposure spreadsheets, aho presented in Appendix E-4. calculate risks and hazard indices for these constituents, using one-half the sample quantilation limit for each constituent as its soil concentration.
NA -Not Analyzed.
NC -Not Calculated.
ND -Not Detected
Filename: HRSSC.WQI
RN:03
22-Jun-92
ail
SURFACESOIL-AREAD
Degraded Nondcgraded
Cone. Degraded Cone. Nondcgradcd
(m,Jkg) Risk (m,Jkg) Risk
ND NC ND NC
ND NC ND NC
ND NC ND NC
5.53E-03 NC 6.89E-Ol NC
ND NC ND NC
ND NC ND NC
2.41E-03 9.15E-11 3.00E-01 1.14E-08
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
NA NC NA NC
9.15E-11 1.14E-08
----TABLE E-4-6b
HYPOlllETICAL ON-SITE RESIDENT-SURFACE SOIL
POTEf'ITIAL NONCARCINOGENIC RISK. SCALING TABLE•
HUMAN IIEAL 111 EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
SURFACE SOIL -AReA A
Degraded Nondegradcd
Cone. Degraded Cone. Nondegraded
CONSTITUE1'"T (mµkg) Risk (mg/kg) Risk
PHENOL 6.29E-04 8.73E-09 7.83E-02 1.09E-06
2-CHLOROPIIENOL ND NC ND NC
2-~1TROPHE:-;OL 3.50E-04 3.65E--07 4.36E-02 4.54E-05
2,4-DIMETHYLPHENOL 4.86E-04 2.02E-07 6.05E-02 2.52E-05
2,4-DICHLOROPHENOL ND NC ND NC
4-CHLOR0-3-METIIYLPHENOL ND NC ND NC
2,4,6-TRICIILOROPIIENOL 8.69E-04 NC 1.08E--01 NC
2,4-DINITROPHENOL 8.87E-04 3.69E--06 1.IOE--01 4.(i()E-04
4-NITROPltENOL 1.llE--03 1.16E--06 1.39E--01 1.44E-04
2,3S,6-TETRACHLOROPHENOL ND NC ND NC
2-METIIYL-4,6,-DINITROPHENOL ND NC ND NC
PENTACHLOROPIIENOL ND NC ND NC
ISOPROPYL ETI-IER ND NC ND NC
TOTAL TCDD-TE NA NC NA NC
TOTAL 5.43E-06 6.76E-04
Notes:
SURFACE SOIL -AREA B
Degraded Nondegradcd Degraded
Cone. Degraded Cone. Nondegraded Cone.
(mF,/kg) Risk (mµkg) Risk (mF,fkg)
ND NC ND NC ND
8.llE-04 l.35E-06 1.0lE-01 1.68E-04 1.00E-03
ND NC ND NC ND
ND NC ND NC l.07E-03
ND NC ND NC 7.72E-04
ND NC ND NC 9.52E-04
ND NC ND NC 6.37E-04
ND NC ND NC 1.lSE--02
ND NC ND NC ND
ND NC ND NC 9.59E-03
ND NC ND NC 1.26E--03
1.31E-03 3.64E--07 1.63E-Ol 4.53E-05 6.50E+OO
ND NC ND NC ND
6.IOE-05 NC l.28E-04 NC 9.71E-02
1.72E-06 2.14E-04
• -Phenolic compounds and pcntachlorophenol were assumed to ha\·c a half-life of 60 days; dioxin was auumcd to ha\'C a half-life of 12 years. (Sec text) .
SURFACE SOIL -AREA cu
Nondegraded
Degraded Cone. Nondegraded
Risk (mg/kg) Risk
NC ND NC
1.67E-06 1.25E-OI 2.08E-04
NC ND NC
4.45E-07 I.33E-Ol 5.55E-05
2.14E--06 9.61E--02 2.67E-04
3.96E--07 1.18E--01 4.93E--05
NC 7.93E--02 NC
4.93E--05 1.47E+OO 6.14E--03
NC ND NC
7.99E-06 1.19E+OO 9.95E-04
5.2.JE--06 1.56E-01 6.51E-04
l.81E-03 8.l0E+02 2.25E-01
NC ND NC
NC 2.04E-01 NC
1.87£-03 2.33E-Ol
.. -Phenol, 2-nitrophcnol, and 4-nitrophcnol were not detected in Arca C surface soils; as such, risks or hazard Indices for these constituents are not displayed here or in Section 5 summary tables.
Exposure spreadsheets, also presented in Appendiit E-4, calculate risks and hazard indices for these constituents, using one-half the sample quantitation limit for each constituent as its soil concentration.
NA -Not Analyzed.
NC -Not Calculated.
ND -Not Detected.
Filename: HRSSNC. WQl
RN:OJ
22-Jun-92
Degraded
Con~
(m,Jkg)
ND
ND
ND
5.53E--03
ND
ND
2.41E--03
ND
ND
ND
ND
ND
ND
NA
lllil iiiil
SURFACESOIL-AREAD
Nondegraded
Degraded Cone. Nondegradcd
Risk (mF,/kg) Risk
NC ND NC
NC ND NC
NC ND NC
2.30E--06 6.89E--01 2.87E-04
NC ND NC
NC ND NC
NC 3.00E--01 NC
NC ND NC
NC ND NC
NC ND NC
NC ND NC
NC ND NC
NC ND NC
NC NA NC
2.30E-06 2.87E-04
-.. .. TABLE E-4-7a
HYPOTI-tETICALON-SITE RESIDENT -SUBSURFACE SOIL
POTENTIAL CARCINOGENIC RISK -SCALING TABLE•
HUMAN HEALTI-1 EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
.. aliJ
SUBSURFACE SOIL· AREA A SUBSURFACE SOIL-AREA B SUBSURFACE SOIL -AREA C
Degraded Nondegradcd Degraded Nondegraded Degraded
Cone. Degraded Co= Nondcgraded Cono. Degraded Con~ Nondegraded Co=
CONSTITUEl"IT (mg/k•) Risk (mg/k,) Risk (mg/k,) Risk (mg/kg) Risk (mg/kg)
PHENOL 7.35E-04 NC 9.15E-02 NC 7.52E-04 NC 9.36E-02 NC ND
2-CHLOROPHENOL 4.25E-03 NC 5.30E-01 NC 4.48E-04 NC 5.58E-02 NC 3.15E-03
2-NITROPHENOL 1.17E-03 NC 1.45E-01 NC ND NC ND NC 5.85E-04
2,4-DIMETI{YLPHENOL 6.72E-04 NC 8.36E-02 NC ND NC ND NC 1.38E-03
2,4-DICHLOROPHENOL ND NC ND NC ND NC ND NC 1.90E--03
4-CHLOR0-3-METI-IYLPHENOL 4.43E-04 NC 5.SlE-02 NC ND NC ND NC 4.92E-04
2.4,6-TRICHLOROPHENOL 7.87E-04 3.87E-13 9.SOE-02 4.828-11 9. 73E-04 4.788-13 1.21E-01 5.95E-11 l.34E-03
2.4-DINITROPHENOL ND NC ND NC ND NC ND NC 4.40E-04
4-NITROPHENOL 9.57E-04 NC l.19E-01 NC ND NC ND NC 1.03E-03
2.3,5,6-ITfRACHLOROPHENOL ND NC ND NC ND NC ND NC 2.04E-03
2-METIIYL-4,6,-DINITROPHENOL ND NC ND NC ND NC ND NC ND
PENTACHLOROPHENOL ND NC ND NC ND NC ND NC 3.78E-01
ISOPROPYL ETI-IER ND NC ND NC ND NC ND NC 6.21E-01
TOTAL TCDD-TE NA NC NA NC 7.55E-06 2.02E-08 l.59E-05 4.26E-08 7.30E-04
TOTAL 3.87E-13 U2B-11 2.02E-08 4.27E-08
Noles:
• -Phenolic compounds and pcntachlorophenol were assumed to have a half-lire of 60 days; dioxin was assumed to have a half-life of 12 years. (See lc:tt.).
NA -Not Anal)'?.Cd
NC -Not Calculated
ND -Not Detected
Filename: HRS BC. WQl
RN:02
19-Jun-92
NondegradeC
Degraded Co= Nondcgradcd
Risk (mg/kg) Rbk
NC ND NC
NC 3.92E-01 NC
NC 7.28E-02 NC
NC 1.72E-01 NC
NC 2.36E--01 NC
NC 6.12E-02 NC
6.57E-13 1.66E-01 8.18E-11
NC 5.48E-02 NC
NC 1.28E-01 NC
NC 2.54E-Ol NC
NC ND NC
2.03B-09 4.70E+0l 2.52E-07
NC 6.21E-Ol NC
1.96E-06 1.54E-03 4.12E-06
l.96E-06 4.37E-06
iiii11 iiiil
SUBSURFACE SOIL. AREA D
Degraded Nondegraded
Con<. Degraded Con<. Nondcgraded
(mg/kg) Risk (mgik,) Risk
8.97E-04 NC 1.12E-Ol NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
5.35E-04 NC 6.65E-02 NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
NA NC NA NC
NC NC
--TABLE E-4-7b
HYPOTI-IETICAL ON-SITE RESIDENT -SUBSURFACE SOIL
POTENTlAL NONCARCINOGENIC RISK -SCALING TABLE•
HUMAN HEALTI--1 EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
---.. liiiiilll
SUBSURFACE SOIL· AREA A SUBSURFACE SOIL -AREA B SUBSURFACE SOIL. AREA C
Degraded Nondcgraded Degraded Nondcgradcc Degraded
Con<. Degraded Cooc. Nondcgradcd Cone. Degraded Con<. Nondcgraded Cooc.
CONSTJTIJENT (m[<il<g) Risk (mg/kg) Risk (mg/kg) Risk (m[<il<g) Risk (mg/kg)
PHENOL 7.3SE-04 3.38E-QC} 9.15E-02 ◄.21!!-07 7.52E-04 3.92E-09 9.36E-02 ◄.88E-07 ND
2-CHLOROPHENOL 4.25E-03 2.35E-06 5.30E-01 2.93E-04 4.48E-04 2.SOE-07 5.SSE-02 3.49E-05 3.15E-OJ
2-NITROPHENOL 1.17E-03 4.04E-07 1.45E-Ol 5.0JE-05 ND NC ND NC 5.85E-04
2.4-DIMETHYLPHENOL 6.72E-04 9.28E-08 8.36E.02 1.16E-05 ND NC ND NC 1.38E-03
2.4-DICHLOROPHENOL ND NC ND NC ND NC ND NC 1.90E-03
4-CHLORO-3-MEIBYLPHENOL 4.43E-04 6.12E-08 5.51E-02 7.62E..Q6 ND NC ND NC 4.92E-04
2,4,6-TRICHLOROPHENOL 7.87E-04 NC 9.SOE-02 NC 9.73E-04 NC l.21E-Ol NC 1.34E..Q3
2.4-DINITROPHENOL ND NC ND NC ND NC ND NC 4.40E-04
4-NITROPHENOL 9.57E-04 3.31E-07 1.19E-01 4.12E-05 ND NC ND NC 1.03E-03
V,5.6-'IBTRACIILOROPHENOL ND NC ND NC ND NC ND NC 2.04E..Q3
2-METIIYL-4,6.-DINITROPHENOL ND NC ND NC ND NC ND NC ND
PENTACHLOROPHENOL ND NC ND NC ND NC ND NC 3.78E-Ol
ISOPROPYL ETIIER ND NC ND NC ND NC ND NC 6.21E-01
TOT AL TC DD-TE NA NC NA NC 7.55E..Q6 NC 1.59E-05 NC 7.30E-04
TOTAL 3.24E-06 4.04E-04 2.84E-07 3.S4E-05
Not.cs:
• -Phenolic compounds and pcnlachlorophenol were assumed lo have a half-life of 60 dayi; dioxin was assumed lo have a half-life of 12 years. (See text).
NA· Not Analyud.
NC -Not Calculated.
ND • Not Detected.
Filename: HRSBNC.WQl
RN:02
19-Jun-92
Nondcgradc,
Degraded Cooc. Nondcgradcd
Risk /mg/kg) Risk
NC ND NC
1.97E-06 3.92E-01 2.45E-04
2.29E-07 7.28E-02 2.85E-05
2.17E-07 1.72E-01 2.70E..Q5
1.98E-06 2.36E..Ql 2.47E-04
7.70E-08 6.12E.02 9.58E..Q6
NC 1.66E.01 NC
6.89E.07 5.48E-02 8.58E-05
4.02E-07 1.28E..Q1 5.0lE-05
6.38E-07 2.54E-01 7.94E-05
NC ND NC
3.94E-05 4.70E+0l 4.91E..Q3
9.72E..Q6 6.21E-01 9.72E--06
NC 1.54E-03 NC
5.53E-05 5.69E-03
_, a.I
SUBSURFACE SOIL. AREA D
Degraded Nondcgradcd
Con<. Degraded Cooc. Nondcgradcd
/mg/kg) Risk (mg/kg) Risk
8.97E-04 4.68E-09 1.12E.-Ol 5.82E-07
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
5.35E-04 2.09E..Q7 6.65E.02 2.60E-05
ND NC ND NC
ND NC ND NC
ND NC ND NC
ND NC ND NC
NA NC NA NC
2.14E-07 2.66E..QS
--TABLE E-4-8a
HYPOTHETICAL ON-SITE RESIDENT -SEDIMENT
POTENTIAL CARCINOGENIC RISK -SCALING TABLE'
HUMAN HEALTH EV ALVA TION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
SEDIMENT -FIRE POND
Degraded Nondcgradec
C.Onc. Degraded C.Onc.
CONSTITlJENT (mg/kg) Risk (mg/kg)
PHENOL 8.75E--04 NC 1.09E-01
2-CIILOROPHENOL l.60E-03 NC 2.00E-01
2-NITROPHENOL 3.97E--04 NC 4.94E-02
2,4-DIMETI-IYLPHENOL 5.41E-04 NC 6.73E-02
2,4-DICHLOROPHENOL ND NC ND
4-CIILOR0-3-MEIBYLPHENOL ND NC ND
2,4,6-TRICHLOROPHENOL ND NC ND
2,4-DINITROPIIENOL ND NC ND
4-NITROPHENOL l.52E-03 NC 1.89E-OI
2,3,5,6-TETRACHLOROPHENOL ND NC ND
2-METHYL-4,6,-DINITROPHENOL 8.45E-04 · NC 1.05E-01
PENTACHLOROPHENOL 9.06E-03 1.44E-10 l.13E+OO
ISOPROPYL ETIIER ND NC ND
TOTAL TCDD-TE 2.12E--04 l.68E-06 4.47E--04
TOTAL t.68E-06
Notes:
liilllll -..
SEDIMENT -WESIBRN DITCH
Degraded Nondcgradec
Nondegradec Cone. Degraded Cone. Nondcgradet
Risk (mg/kg) Risk (mg/kg) Risk
NC 9.l3E--04 NC 1.14E-01 NC
NC 3.72E-03 NC 4.63E-OI NC
NC 2.83E-03 NC 3.52E-01 NC
NC ND NC ND NC
NC l.S0E-03 NC 1.87E-Ol NC
NC 6.41E-04 NC 7.98E--02 NC
NC ND NC ND NC
NC ND NC ND NC
NC ND NC ND NC
NC ND NC ND NC
NC ND NC ND NC
t.79E-08 1.33E-03 1.78E-11 J.65E-01 2.22E-09
NC NA NC NA NC
3.54E-06 7.89E-05 5.29E-07 l.66E--04 l.IIE-06
3.56E-06 5.29E-07 1.12E-06
• -Phenolic compounds and pentacblorophcnol were assumed lo have a half-life or 60 days; dioxin was assumed to have a hal£-lire or 12 years. (See text).
NA -Not Analyzed
NC -Not Calculated
ND -Not Detected
File Name: HRSDC.WQl
RN:02
19-Jun-92
-iiiiil iilil liiil
------.. -TABLE E-4-8b
HYPOTHETICAL ON-SITE RESIDENT -SEDIMENT
POTENTIAL NONCARCINOGENIC RISK -SCALING TABLE"
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
SEDIMENT -FIRE POND
Degraded Nondegradec
C:Onc. Degraded C:Onc.
CONSTITUENT (mg/kg) Rist (mg/kg)
PHENOL 8. 75E--04 4.65E-10 l.09E-01
2-CHLOROPHENOL 1.60£--03 l.02E-07 2.00E--01
2-NITROPHENOL 3.97E--04 l.58E--08 4.94£-02
2,4-DIMETHYLPHENOL 5.41E--04 8.63E--09 6.73E--02
2,4-DICHLOROPHENOL ND NC ND
4-CHLOR0-3-METHYLPIIENOL ND NC ND
2,4.6-TRICIILOROPHENOL ND NC ND
2,4-DINITROPHENOL ND NC ND
4-NITROPIIENOL 1.52£--03 6.05E--08 1.89£-01
2.3.5,6-TETRACHLOROPHENOL ND NC ND
2-METI-IYL-4.6.-DINITROPHENOL 8.45E--04 Ll5E-07 l.0SE-01
PENTACHLOROPHENOL 9.06E--03 9.64E--08 1.13E+OO
ISOPROPYL ETHER ND NC ND
TOTAL TCDD-TE 2.12E--04 NC 4.47E--04
TOTAL 4.19E-07
Notes:
----
SEDIMENT -WESTERN DITCH
Degraded Nondegradec
Nondegraded Cone. Degraded Cone. NondegradeC
Rist. (mg/kg) Risk (mg/kgj Risk
5.79E--08 9.13E-04 7.00E-10 1.14£-01 8.72E--08
1.27£-05 3.72E--03 3.42E-07 4.63£-01 4.26£-05
I.97E--06 2.83E--03 1.63£-07 3.52E-01 2.02E--05
I.07E--06 ND NC ND NC
NC I.50E--03 2.30£-07 1.87£-01 2.86E--05
NC 6.41£-04 1.48£-08 7.98£-02 l.84E--06
NC ND NC ND NC
NC ND NC ND NC
7.54E--06 ND NC ND NC
NC ND NC ND NC
l.68E--05 ND NC ND NC
l.20E--05 1.33£--03 2.04E--08 1.65E-01 2.SJE-06
NC NA NC NA NC
NC 7.89E--05 NC 1.66£--04 NC
5.22E--05 7.71E-07 9.60E--05
••Phenolic compounds and pcntachlorophenol were assumed to have a hair-life of 60 days; dioxin was assumed to have a half.life of 12 years. (Sec text).
NA· Not Analyzed..
NC -Not Calculated..
ND -Not Detected..
File Name: IIRSDNC.WQI
RN:02
19·JUD·92
-lilll llll ..
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APPENDIX G
G.O INTRODUCTION
The purpose of this Appendix is to identify both risk-based target clean-up levels (RBTCLs) and
remediation goals for constituents in various environmental media at the former Koppers
Company, Inc. Site in Morrisville, North Carolina. This evaluation is intended to complement the
revised Baseline Risk Assessment report for this Site.
As described in Section 2.0, the Morrisville Site (subsequently designated "the Site") is the
location of a former wood treating process, referred to as the Ce/Ion process, as well as a
current wood laminating facility (see Figure G-1 ). While the Site and its operations have changed
hands several times in the past, Unit Structures, Inc. is the current operator and principal owner.
Beazer East, Inc., formerly Koppers Company, Inc., still retains ownership of a portion of the
Site, but no operations currently exist on this portion. The Ce/Ion treating process involved the
treatment of lumber with pentachlorophenol. As shown in Figure G-1, and as defined in the
baseline risk assessment and the RI, the potential areas of interest at the Site are three discrete
on-Site ground water areas and off-Site ground water, six discrete areas of surface water and
sediment on and near the Site, and four discrete on-Site surface and subsurface soil areas. The
three discrete on-Site ground water areas are defined as: the Eastern Area, the Western Area,
and the Former Lagoon and Ce/Ion Process Area. The six discrete on-and off-Site surface water
and sediment areas are defined as: Fire Pond, Discharge Stream from Fire Pond, Medlin Pond,
Discharge Stream from Medlin Pond, Eastern Ditch and Western Ditch. The four discrete on-Site
soil areas are defined as: Area A -former landfarm area, Area B -former tepee burner and
eastern area, Area C -former Ce/Ion process area and former lagoon area, and Area D -the Unit
Structures active facility. Fish were sampled in Fire Pond on-Site and in off-Site surface water
bodies (Medlin Pond and the Control Pond to the south-west of the mapped area). A more
detailed description of the Site history can be found in Section 2.0 of the baseline risk
-assessment.
G.0.1 Scope of Study
I This Appendix presents the derivation of RBTCLs and discusses their application. The RBTCLs
are based on both potential assumed carcinogenic risks 1 to hypothetical human receptors and
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'These risks are characterized as "assumed" because the exposures being discussed are hypothetical in that there is currently no one living or working in the specific location for
which the risk is calculated, but it is conceivable that someone could occupy that location
R:\PUBS\PROJECTS\0845008\000.APG G-1 June, 1992
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also potential assumed risks to hypothetical ecological receptors evaluated in the risk
assessment report. The portion of the risk assessment from which the human health RBTCLs
are derived was conducted in accordance with current EPA guidance, including: Risk
Assessment Guidance for Superfund: Volume I, Human Health Evaluation Manual (U.S. EPA,
1989c); Supplemental Region IV Risk Assessment Guidance (U.S. EPA, 1991 b); Exposure
Factors Handbook (U.S. EPA, 1989b); and Superfund Exposure Assessment Manual (U.S. EPA,
1988c). The risk assessment included, for the chemical constituents of interest, all relevant
exposure pathways. Potential assumed risks were estimated in the baseline risk assessment for
potential assumed exposures to phenolic compounds (including pentachlorophenol), isopropyl
ether and polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans2 occurring in
surface and subsurface soils, surface water bodies, sediments and ground water. The results
of the baseline risk assessment show that almost one hundred percent of the potential assumed
risk estimated in the baseline risk assessment is attributable to two constituents:
pentachlorophenol and PCDD/PCOF. Thus, these two constituents are identified as the
constituents of interest at this Site. This Appendix evaluates potential exposures to
pentachlorophenol and PCOO/PCDF.
Based on the potential assumed exposures to pentachlorophenol and PCDD/PCOF and the
associated estimates of potential assumed risks to human receptors, RBTCLs are determined
for each of two potential Site use conditions. The first condition assumes that the Site remains
commercial/industrial. This is the most likely future Site use scenario, as current development
at some future time. The risks are also "assumed" because, even if such an exposure were
to occur, it is only assumed that the exposure concentration and duration would interact
according to the assumed dose-response model to produce the specified adverse effect.
It is further 'assumed" because, in many cases, the specified adverse effect is based
upon numerous conservative assumptions, including that the effects observed in laboratory
animals and their mechanism of causation will also occur in humans. This is not true in
many cases.
These risks are described as "potential" because, even if all of the above assumptions
are met, the duration of exposure is assumed to be many years (up to 30) in duration, with
no change in the rate of exposure to an actual person, before the effect would be expected
to occur. Thus, even if an actual exposure, rather than a hypothetical one, can be
demonstrated in a particular case, the predictions of risk made for that location can be
characterized as an "potential assumed" risk and, therefore, this nomenclature is used
throughout.
2Also referred to as: PCDD /PCDF to represent the class of constituents. Reference to
the isomer 2,3,7,8-TCDD also appears when a standard or other factor is specific for this
isomer. TCDD-TE refers to the conversion of the class of constituents to 2,3,7,8-TCDD-Toxic
Equivalents. This conversion is done to estimate the potential relative contribution of various
isomers.
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in this area has been commercial/industrial in nature. The second, and less likely scenario,
assumes that the Site is developed for future residential use.
The ecological risk evaluation was conducted in accordance with currently available EPA
guidance: Risk Assessment Guidance for Superfund: Volume II: Environmental Evaluation
Manual (U.S. EPA, 1989d); Recommendations for and Documentation of Biological Values for Use in Risk Assessment (U.S. EPA, 1988a}; Quality Criteria for Water, 1986 (U.S. EPA, 1986); Review of Ecological Risk Assessment Methods (U.S. EPA, 1988b); and Ecological Assessment
at Hazardous Waste Sites (U.S. EPA, 1989a). However, as discussed in Section G.3 of this
Appendix, ecological RBTCLs were not derived for potential assumed exposures of either terrestrial or aquatic receptors because either appropriate dose-response values were not
available, or the potential assumed risks, if any, were within or below target levels.
G.0.2 Organization of Appendix
Section G.1 describes the method used to derive RB TC Ls and how they can be used to develop
remediation goals. Section G.2 briefly describes the methodology used in the baseline risk assessment report to estimate the potential assumed risks to potential human receptors. Section
G.3, Ecological RBTCLs, briefly describes the methodology used in the risk assessment report
to estimate the potential assumed risks to ecological receptors and discusses how ecological
RBTCLs could be derived and why they are not. Section G.4 presents a comparison of the
derived RBTCLs with federal and state "applicable and relevant or appropriate requirements"
(ARARs) and other guidelines or standards for the constituents of interest. Section G.5
summarizes the findings of this evaluation and reports several important conclusions.
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G.1 Derivation and Application of RBTCLs
The end result of a baseline risk assessment is estimation of potential assumed risks for all
people hypothetically contacting constituents on a site. Potential assumed risks are generally
estimated for all possible combinations of hypothetically exposed people and environmental
media containing constituents at the site. As is often the case, the potential assumed risks, if
any, for the majority of combinations of potentially exposed people and environmental media will
fall within a range of risks considered acceptable by regulatory agencies. If potential assumed
risks, if any, for some combinations are greater than is considered acceptable by regulatory
agencies, some kind of remedial action may be required. Generally, the goal of the site
remediation process is to decrease the potential assumed risks associated with the constituents
in the environmental media such that they are equal to, or less than, the range of risks
considered acceptable by regulatory agencies.
Reductions in potential assumed risk can be accomplished in two ways. First, the potential for
local residents or workers to contact the constituents can be reduced or eliminated. For
example, fencing an area will restrict access and reduce potential assumed exposures and
related potential risks. Second, the concentration of the constituents themselves can be
reduced. For example, bioremediating soils that have the highest concentrations of chemical
constituents of interest will reduce the average constituent concentration of soils at the site.
This evaluation assumes that the goal of remediation at the Site is to reduce the concentration
of the constituents remaining on the Site such that unacceptable risk levels are not exceeded.
For environmental media with constituent concentrations that result in potential assumed risks
that exceed the acceptable (or target) risk levels, this evaluation derives goals for constituent
concentrations that will meet the target risk levels. The methodology used to derive the RBTCLs
is presented in Section G.1.1. Section G.1.2 describes how RBTCU; (shoulEI) may be applied
during remediation of a site.
G.1.1 Derivation of RBTCLs
The baseline risk assessment used a series of assumptions about the constituents present on
the Site and about the behavior of people who live or work near the Site in order to establish a
hypothetical relationship between the concentration of a constituent on the Site and an potential
assumed risk associated with that constituent concentration. The hypothetical relationship is
considered to be linear within the range of particular constituent concentrations and associated
potential risk levels identified on Site. In other words, increasing the concentration of a
constituent two-fold, increases the potential assumed risk by two-fold. Because the risk
assessment has identified those media on the Site that exceed target risk levels, and has also
A:\PUBS\PROJECTS\0845008\000.APG G-4 June, 1992
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quantified the potential assumed risk based upon the concentration of constituents in those
media, RBTCLs can be derived using a relatively simple procedure as shown in the hypothetical
example below.
Consider a hypothetical example in which the potential assumed risk associated with a particular
constituent in a particular environmental medium exceeds the target risk level by three-fold. The
potential assumed risk needs to be reduced by three-fold to set the potential assumed risk at
a level equal to the target risk level. Because the relationship between potential assumed risk
and constituent concentration is linear, the required three-fold reduction in risk can be achieved
by reducing the existing constituent concentration in that environmental medium by three-fold.
Thus, the RBTCL for this constituent in this environmental medium is equal to the existing
concentration divided by three. This same procedure can be used to derive RBTCLs for all other
environmental media that have potential assumed risks that exceed target risk levels using the
following relationship:
RBTCL = Existing constituent concentration x target risk level
Potential assumed carcinogenic risk.
As discussed in the hypothetical example above, this relationship makes clear that the RBTCL
is equal to the existing constituent concentration reduced by the ratio of the target risk level to
the potential assumed risk. This relationship is used to derive RBTCLs for all constituents in the
various environmental media at the Site.
Section G.1.1.1 describes the different hypothetical future Site use conditions, and the receptors
assumed to be exposed to the Site under those conditions. RBTCLs were derived in this
Appendix for each of the receptors evaluated in the baseline risk assessment.
As described in the baseline risk assessment, degradation factors were applied to existing
constituent concentrations of phenolic compounds and PCDD/PCDF in soil and sediment.
Section G.1.1.2 describes the application of degradation factors in the derivation of RBTCLs.
G.1.1.1 Potential Future Site Use Conditions
RB TC Ls were developed for two potential future Site use conditions. The first condition assumes
that the Site remains commercial/industrial. This is the most likely future Site use scenario, as
current development in the area has been commercial/industrial in nature. The second, and less
likely scenario, assumes that the Site is developed for future residential use. The potential for
residential development at this Site is considered unlikely because recent development in the
area has been commercial/industrial, and the Site is currently occupied with industrial
enterprises. In addition, institutional controls, such as placing a land-use restriction on the deed
R:\PUBS\PROJECTS\0845008\000.APG G-5 June, 1992
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EN31.
for the property preventing residential use, can and will be introduced by Beazer to assure that
its portion of the Site remains commercial/industrial.
Hypothetical receptors were evaluated for each of two potential future Site use conditions
evaluated in the baseline risk assessment. On-Site Workers and Local Off-Site Residents were
evaluated for the commercial/industrial Site use scenario. The Local Off-Site Resident evaluation
includes the potential exposures of teenagers trespassing on the Site. At the request of EPA,
hypothetical On-Site Resident receptors were evaluated for potential future residential use of the
Site.
G.1.1.2 Degradation of Constituents
As discussed in Appendix E, the first drafts of the baseline risk assessment assumed that
phenolics and PCDD /PCDF degrade naturally over time. This was based upon a literature
review which indicated that these constituents degrade in soils. Given this evidence, and that
EPA risk assessment guidance (U.S. EPA, 1989c) allows for consideration of degradation when
estimating potential assumed risks, degradation of phenolic compounds and PCDD /PCDF were
assumed to occur in soils and sediment. Based upon review and comment by EPA, a more
detailed literature review of degradation of phenolic compounds was undertaken and is
summarized in Table -f94t G-1 [in the baseline risl1 assessment]. This review provided
conclusive evidence of degradation of phenolic compounds in a variety of conditions including
aerobic and anaerobic soils, and aerobic and anaerobic aqueous conditions. Thus, it is
appropriate that degradation should be considered when estimating potential assumed risks and
also when deriving RBTCLs. The more detailed review did, however, report slower degradation
rates than assumed by the baseline risk assessment. In particular, the baseline risk assessment
assumed a degradation rate (half-life) of 60 days for phenolic compounds, including
pentachlorophenol. This was based upon doubling the highest reported degradation rate (of 30
days) for pentachlorophenol. The more recent literature review identified a maximum
degradation rate of 178 days for pentachlorophenol in aerobic soils and a maximum of 4.2 years
for anaerobic soils. Based upon this evidence, two sets of RBTCLs for pentachlorophenol were
derived to represent a conservative estimate of exposure at this Site: RBTCLs based on the
degradation rates used in the baseline risk assessment; and RBTCLs based on alternate
degradation rates. The RBTCLs based on alternate degradation rates include a degradation half
life of pentachlorophenol in surface soil of 1 year (almost double the longest half-life reported for
pentachlorophenol) and in subsurface soil and sediment of 5 years (slightly greater than the
maximum half-life reported in the literature).
Degradation half-lives and RBTCLs derived assuming degradation should be checked against,
and possibly limited by, several flwet factors. [ The first is that when the half life is 1:1sed to
R:\PUBS\PROJECTS\0645006\000.APG G-6 June, 1992
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eaol1 oaloulate fFom eicisting oonstituent ooneentrations to eonstituent eoneentFations at the time
a faeility oeased opeFation, rnasonaelo oonoenlrations at the time of oessation of ope1ation
should ee pFOdioled. The hall life of 1 year for pentaohlorophenol used to deri•1e alternate
RBTGbs in surfaee soil prediots that the ei1isting average surfaoe soil oonoenlFation of
pontaohlorophenol in /\roa C {3Be mg/l<g) would have averaged 3992 mg/l<g in 197§, the year
that operations oeased at this Site. Tho estimated pontaohlorophenol eonoentration at the time
of oessation is Feasonaele indisating that the hall life of 1 year in surfaoe soil is also reasonaele.
Similarly, the half life of e years for pentaohlorophenol in suesurfaoe soil and sediment, also
prediets reasonaele eonoentrations at the time of oessation in 197s.}
[The seoond faotor] One factor that should be considered is to limit the RBTCL based upon
degradation at a constituent concentration that protects against assumed potential acute effects
as well as assumed potential chronic effects. Because no acute dose-response value for
pentachlorophenol was available, the sub-chronic reference dose for pentachlorophenol (3E-02
mg/kg-day) (U.S. EPA, 1990) was used in this evaluation. The pentachlorophenol concentration
in surface soil that is protective of sub-chronic effects was estimated assuming a 15 kg child
ingests 200 mg of surface soil every day. The maximum concentration of pentachlorophenol in
surface soil that is protective of sub-chronic effects is 2250 mg/kg. The RBTCLs for
pentachlorophenol are less than this concentration. If chronic RBTCLs had been higher, it would
need to have been limited at the concentration protective of assumed potential sub-chronic
effects.
Similarly, the RBTCLs for PCDD/PCDF in surface soil, subsurface soil and sediment, and
pentachlorophenol in subsurface soil and sediment, do not exceed the concentrations protective
of acute effects, and thus, the RBTCLs are protective of assumed sub-chronic as well as
assumed chronic effects.
As discussed in Appendix E, at the request of U.S. EPA Region IV, the calculations used to
estimate potential assumed risks that included degradation factors were edited to remove these
factors from the main text of the final report because no site-specific data confirming the
degradation of constituents in various media is available. The main text of this report shows only
the results from the evaluation that assumes no degradation will occur. These results are also
discussed in this Appendix. Because there is evidence in the literature that supports the
degradation of pentachlorophenol and dioxin, soil and sediment calculations including the
assumption of degradation are also included in this Appendix. As described above, two sets of
degradation rates were used in the derivation of RBTCLs for pentachlorophenol, 60 days (as was
used in the first drafts of the report and is summarized in Appendix E), and 1 year (based on a
more detailed literature search on the degradation of pentachlorophenol). U.S. E,PA Region IV
has not approved of the application of any degratation rates found in the literature, yet if
R:\PUBS\PROJECTS\0845008\000.APG G-7 June. 1992
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literature-derived degratation rates are to be used, Region N has reported a preference for the
1 year half-life for pentachlorophenol in surface soils, and not 60 days as was first used in this
baseline risk assessment. If the half-life for pentachlorophenol is assumed to be 1 year, the
potential assumed risks estimated in Appendix E would have been slightly higher than those
presented (which are based on a half-life of 60 days). [Tho soil anel soelimont RBTCLs eloFivoel
horn inoluelo Elegraelation.) (Two) Therefore, three sets of RBTCLs were derived for
pentachlorophenol for each relevant receptor, RBTCLs derived assuming no degradation occurs,
RBTCLs using degradation rates used in the baseline risk assessment, and RBTCLs using
alternate degradation rates taken from the literature and summarized here. Two sets of RBTCLs
were derived for dioxin for each relevant receptor, RBTCLs derived assuming no degradation
occurs, and RBTCLs using degradation rates used in the baseline risk assessment. The
recommendations for potential remediation at tho Site (see Section G.5) were based on RBTCLs
assuming degradation does not occur, as requested by EPA (eleriveel using alternate elegraelation
rates. Tho RBTCLs eleriveel loF alternate aegraelation Fates arn proteotive of long term effeots anel
arn prnteotivo of potential assumes sub ohrnnic effects. /\dditionally, tho half lives can be used
to prediot FOasonablo levels of oonstiluent present al the Silo at the time operations were ceased
in 197§.)
Constituent concentrations in surface water, ground water and fish were not adjusted for
degradation in the baseline risk assessment, nor in this clean-up levels evaluation, because
constituent concentrations need to meet existing standards in surface water and ground water,
and no information was available in the scientific literature to thoroughly evaluate degradation
of the constituents of interest in fish.
G.1.2 Application of RBTCLs
The potential assumed risks estimated by the baseline risk assessment report are based upon
long-term or chronic exposures. Thus, over the duration of exposure assumed by the risk
assessment, local residents and workers are assumed to potentially come into contact with
environmental media in different areas of the Site many times. Given the characteristics of the
areas of the Site investigated, this contact is assumed to be random in each area. In other
words, every time a person is assumed to contact an environmental medium in one of the areas
on the Site, that contact can potentially occur anywhere in that area. There are no characteristics
of the areas of the Site investigated by the risk assessment that suggest environmental media
with the highest constituent concentrations will be preferentially contacted by a worker or local
resident. If there were something unique and attractive on an area of a site with the highest
constituent concentrations -for example, a swing-set or baseball diamond -such an area could
be preferentially contacted. However, this is not the case at this site because the environmental
R:\PUBS\PAOJECTS\0845008\000.APG G-8 June, 1992
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media within each of the areas on the Site investigated by the risk assessment are relatively
uniform and contact is likely to be random.
The repeated random potential contact with constituent concentrations over the exposure period
assumed by the risk assessment effectively averages the constituent concentration a hypothetical
person is exposed to over that period. Thus, over the duration of hypothetical exposure, a
person will be exposed to the average constituent concentration, rather than the maximum or
some upper or lower bound concentration. Indeed, the probability of a person being exposed
to an upper bound constituent concentration becomes vanishingly small. This situation is
illustrated by Figure G-2 which was developed to illustrate the central limit theorem. The basic
principle of this theorem is that regardless of how skewed the original distribution is (the top of
Figure G-2), the distribution of the means of several sets of samples will be closer to a normal
distribution with a most frequent result approaching the arithmetic average of the original
distribution (center of Figure G-2). When the number of samples in a set is very large, the
distribution of means becomes normally distributed, or centered around the arithmetic average
(bottom of Figure G-2). This phenomenon should be accounted for when applying RBTCLs to
determine site remediation requirements. In particular, because of this phenomenon, it is the
average concentration of a constituent in an area of the site that needs to be equal to the RBTCL
or other clean-up goals based on potential assumed long term exposures.
Although the concept of using average constituent concentrations as the measurement for the
determination of the need for remediation of a medium or area on a site makes conceptual
sense, there is no clear regulatory policy mandating this approach in determining remedial
actions at a site. The current regulatory policy is to compare maximum measured constituent
concentrations against selected remedial goals and 'remove' everything that exceeds the
selected remedial goal. At the direction of U.S. EPA Region IV, maximum constituent
concentrations were compared with the RBTCLs, ARARs and other applicable standards in this
report. The tables which present the potential remedial goals (RBTCLs, ARARs and other
applicable standards), however, include average, RME and maximum constituent concentrations
for the purpose of comparison.
[Achieving tho goal of having tho RBTCL equal the average concentration does not require that
all portions of an en•~ironmental medium that mmeed tho RBTCL in an area of a site be romoved.
If those areas with the highest constituent concentrations are removed, tho average
conoentration oan be reduoed to equal to or less than tho RBTCL. This can be aooomplished
using a relatively simple prooedure desoribed below.)
[First, tho samples of an environmental medium from a partioular site or area of a site are ranlwd
from the highest to the lowest oonstituent conoontration. Then tho average oonstituent
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eeneentmtien ef all ef tho samples is eleteFrnineel. The avemge is eernpaFeel te the RBTCL. If
the a·,•eFage is less than the RBTCL, then ne Ferneeliatien is noeossary. If the avemge Ol<eeoels
the RBTCL, tho sample with tho highest eenstituent eeneen!Fatien is assurneel te be Fernoeliatoel
anel, as a Fosult, its eonstiluenl eeneentmlien is Feelueeel to zoFe, the eletoelien limit feF !hat
eenstituent, eF serne fmelien ef the elotoetien limit. The a·,emgo ef all ef the samples, inelueling
the sarnplo assurneel te be Ferneeliateel with its new eenstituent eeneen!Fatien, is Feealeulatoel.
If tho avemgo is gFealeF than tho RBTCL, then tho above pFOeeeluFo is Fepoatoel until tho avoFago
is loss than tho RBTCL. If tho avomgo is loss than tho RBTCL, then tho goal of Fornoeliation, as
elefineel, has been aehieveel. All samples with eenstituont eeneen!Fatiens grealeF than that ef tho
highest rnrnaining sample will neeel te be rerneeliateel. Tho highest rnrnaining eensliluent
eeneontmlien ean be FefoFFeel te as the 'piel< up lo•,•el,' boeauso all ef tho samples with
eenstituenl eeneenlmliens gFeateF than the highest Fernaining eeneenlmtien rnust be "piel<eel up."
Twe hypelhetieal eimrnples aFe presenleel below le illus!Fale he.,.., picl< up levels aFe eleFiveel anel
hew they arn Felaleel te RBTCLs.
Beth 0Jmrnples aFe illustFaleel by Table G 1. Assume that this hypelhelical listing ef surtaee soil
rneasurernenls were ebtaineel feF a elesignaleel aFea ef a site containing a partieulm constituent
ef inteFest. The elala aFe FeaFmngeel in the seeenel pair ef eelurnns te set up tho analysis ef the
effectiveness ef a selecleel RBTCL feF elotoFrnining Forneeliatien Foquirernents. Tho last thFeo
celurnns ef Table G 1 list tho ave Fago cencontFatien Fernaining if all cencontFaliens ef eenstituont
grnaleF than the value le the loft (in the sarno rn,•~ have been Ferneveel anel Feplaceel with "clean
sail." Clean sail is that in which the constituent is net eletectable, anel theFefeFO assurneel te hai,•e
the sarno spocilioel eeneentmtien (in this ease ao ppb) as ethoF leeatiens feF whieh samples we Fe
fauna te be belmv the elotoctablo limit (BDL) ef the analysis rnetheel.
If, feF eJEarnple, an RBTCL ,,,alue ef 100 ppb is solecteel feF this hypethetieal site, the ebseFVeel
elistributien of ceneentmtiens suggests that Ferne1,al ef enly tho sail eentaining 9,600 ppb ef the
constituent 11,1eulel be noeessary to pFOtect to the tmget Fisk 101,el useel te eleFi','O the RBTCL feF
this hypothetical site anel particulaF eiEpesuFe seenmie. As seen fFOFR this sirnplifieel ei1arnple,
in spite ef the fast that ene area with eenstituent eeneentFatiens as high as 600 ppb FOFRains,
applying the RBTCL ef 100 ppb in this rnanneF pFOtoets tho potentially oi1peseel FoeepteFs te a
potential Fisl< level that is below the taFget Fisl1 lo•,el. Five hunelFoel ppb weulel effectively be tho
"picl< up level.' That is, all eencentFatiens greateF than 600 ppb weulel be "picl<eel up."
SirnilaFly, if 60 ppb (!he rninirnurn eleteetablo level assurneel hern) weFO seloeteel as the elesiFeel
RBTCL feF this hypothetical ei1arnple, Table G 1 shews that this RBTCL can be aehieveel by
Ferneving only the sails with 9600 ppb anel 600 ppb cencentmtiens. The "picl< up level" to rnoet
an RBTCL of 60 ppb is 100 ppb.
A:\PUBS\PROJECTS\0845008\000.APG G-10 June. 1992
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One outstanding eonsidoralion is whether RBTGLs should be compared to the average
eonslituent eoneentralion of a site or to the upper 06% eonfidenee interval (GI) eonsliluent
eoneentralion. Due to sampling error, eomparison to tho average would seemingly only load to
60% sonfidenso that the real average, and therefore the target risl< level, will not be oicseeded,
',Yhile somparison lo Iha upper 06% GI sonsliluont sonsentration would seemingly lead to 06%
sonfidense that tho real average will not be eirneeded and thus seemingly, 06% sonfidonse that
the potential assumed risl<s will be below the target risl< level. In reality, the stalislisal sonfidense
that potential assumed risl<s aro less than the target risl< le>;el is mush groater than the 06%
bosause of the numerous sonservati>;e assumptions used in the methodology used to derive
RBTGLs.
For eicample, tho saneer slope faster used to derive RBTGLs is the 05% upper bmmd of the
distribution sf sanser slope faslors predisted by a partisular dose response model. In addition,
several equally valid and sommonly used alternative dose response models Olcist to salsulate
sanser slope fastors. All of these models estimate lower sanser slope faslors than the model
used to Elerive RBTGLs in this AppendiK Thus, the sanser slope faster useEI in this evaluation
may represent an upper 00.0% or e•,•en 99.99% upper bound of the entire universe of possible
sansor slope fastors.
A similar analysis sould be oondueted for other assumptions used to Eleri>1e the RBTGLs. II
would show that most of the other assumptions are also upper bounds, though perhaps not as
high an upper bound as the sanser slope faster. As a result, one san bo more than 99.9%, or [
oven 99.99%, sertain that the potential assumed risl< is less than the target risl< le>;el when the !
I average sonstiluent sonsenlration is equal to the RBTGL. Gi•,<en this le•,•el of sonfidenoe in Iha I
'protesti>,•eness' of the RBTGL, ii does not seem nesessary to use the 05% GI of oonslituonl 1
sonsenlration. The slalislioal sonfidense of the RBTGL alone assures greater than the 05% i
sonfidense that tho target risl< level will not be eicseedeEI, even if the aslual a•,1erage sonstituentl I
oonsentralion is soFRewhat greater than the salsulated average sonslituonl sonsentration.
Dospilo tho sonservatism built into the prosess, sonsentralions other than tho a\•erage may be
e·,•aluated •1,1hen developing remeElial goals. The same method dessribed abo11e san bo applied
to other stalislisal estimates of sonstituent sonsentration, suoh as the upper 96% sonfiElense
interval on the arithmetis mean sonsentration. /\t the request of E!PA, somparisons were maEle
in this evaluation between average, RME! (upper 05% or mmdmum), and maidmum
sonsenlrations, with RBTGLs and other remedial goals.
t
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G.2 Human Health RBTCLs
Human health RBTCLs are derived for the two constituents of interest at the Site:
pentachlorophenol and PCDD/PCDF. RBTCLs are derived for each constituent of interest in
each environmental medium and area of interest for each of the two hypothetical future Site use
conditions. The first set of RBTCLs are derived assuming that the Site remains
commercial/industrial in the future. This is the more likely of the two potential future Site use
conditions. The second set of RBTCLs is derived assuming hypothetical residences are
eventually constructed on the Site. This potential Site use is considered unlikely. Recent
development in the area has been commercial/industrial, and the Site is currently occupied with
industrial enterprises3• As described previously, RBTCLs are derived assuming no degradation
occurs, and assuming degradation of pentachlorophenol and dioxin occurs as presented in
Appendix E of the baseline risk assessment report. Additional RBTCLs are derived here for
potential soil and sediment exposure to pentachlorophenol for each future Site use condition
using alternate degradation rates as described in Section G.1.1.2.
The tables described in the following sections, present the RBTCLs for each sonstituent, receptor
and medium at three target risk levels (1 E-04, 1 E-05, and 1 E-06). The target risk level identified
as the remedial goal for this Site will be selected by U.S. EPA Region N. Beazer East, Inc.
supports remedial goals set at the 1 E-05 level for this Site based on the likely future use of the
Site as commercial/industrial.
The methodology for deriving RBTCLs was described in Section G.1. The risk assessment
methodology for deriving estimates of assumed risk is summarized in Section G.2.1. RBTCLs
derived for each constituent for the commercial/industrial Site use are discussed in Section
G.2.2; those derived for the residential Site use are discussed in Section G.2.3.
G.2.1 Review of the Human Health Risk Assessment
The human health risk assessment was prepared following EPA guidance documents: Risk
Assessment Guidance for Superfund: Volume I, Human Health Evaluation Manual (U.S. EPA,
1989c); Supplemental Region IV Risk Assessment Guidance (U.S. EPA, 1991 b); Exposure
Factors Handbook (U.S. EPA, 1989b); and Superfund Exposure Assessment Manual (U.S. EPA,
1988c).
3 In addition, institutional controls, such as placing a land-use restriction on the deed for the
property preventing residential use, can and will be introduced by Beazer to assure that its
portion of the Site remains commercial/industrial.
R:\PUBS\PROJECTS\0845008\000.APG G-12 June, 1992
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The human health evaluation includes a 'Hazard Identification' or selection of constituents of
interest, an evaluation of the relative assumed toxicity of constituents, a quantitative exposure
assessment and a characterization of potential assumed risk.
Section G.2.1.1 reviews the Hazard Identification and Toxicity Assessment sections of the
baseline risk assessment. Section G.2.1.2 reviews the Exposure Assessment section of the
baseline risk assessment.
G.2.1.1 Summary of Hazard Identification and Toxicity Assessment
All detected constituents were evaluated for their potential toxicity and mobility or persistence
in the environment in the hazard identification section of the baseline risk assessment. The
constituents of potential interest selected for quantitative analysis in the risk assessment included
phenolic compounds, pentachlorophenol, isopropyl ether and PCDD/PCDF. The results of the
baseline risk assessment show that remediation of the Site may be required based on the
potential for increased assumed carcinogenic risk from exposure to pentachlorophenol and
PCDD /PCDF in various media of interest. Because approximately one hundred percent of the
potential assumed risk estimated in the baseline risk assessment is attributable to
pentachlorophenol and PCDD/PCDF, the list of constituents of potential interest evaluated in the
baseline risk assessemnt can be shortened to two constituents of interest for the purpose of
deriving human health RBTCLs: pentachlorophenol and PCDD/PCDF.
The toxicity assessment section of the baseline risk assessment reviewed the potential assumed
carcinogenic and noncarcinogenic effects of exposure as prescribed by EPA. The baseline risk
assessment evaluated both the potential assumed carcinogenic effects and the potential
assumed noncarcinogenic effects of all of the constituents of interest. Only three constituents
are considered to be potentially carcinogenic by EPA: pentachlorophenol, 2,4,6-trichlorophenol
and 2,3,7,8-TCDD. The RBTCLs presented in this document are derived for assumed
carcinogenic risks to pentachlorophenol and PCDD/PCDF only. RBTCLs are not derived for
2,4,6-trichlorophenol because almost one hundred percent of the potential assumed excess
carcinogenic risk is attributable to pentachlorophenol and PCDD /PCDF. RBTCLs are not derived
for noncarcinogenic effects because the constituent concentrations low enough to be protective
against potential assumed carcinogenic effects are much lower than those necessary to protect
against potential assumed noncarcinogenic effects. This makes the potential assumed
carcinogenic risks for these constituents a more sensitive indicator of potential assumed adverse
effects; and it will result in the derivation of RBTCLs which are protective against both potential
assumed carcinogenic and potential assumed noncarcinogenic effects.
R:\PUBS\PROJECTS\0845008\000.APG G-13 June, 1992
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In addition, the results of the risk assessment show that only one situation of potential assumed
exposure, a hypothetical on-Site resident drinking ground water in the Eastern Area, results in
a pathway-specific hazard index greater than 1.0, the EPA's threshold of concern for
noncarcinogenic effects. In this case, RBTCLs for assumed carcinogenic effects were also
derived for constituents in Eastern Area ground water. Since the latter concentration
requirements were lower, it is apparent that these RBTCLs will also be protective of any potential
assumed noncarcinogenic effects from potential assumed exposure to Eastern Area ground
water as drinking water.
G.2.1.2 Summary of Exposure Assessment
The exposure assessment includes the evaluation of hypothetical receptors who may potentially
contact constituents on and near the Site. Hypothetical receptors for two separate future
assumed Site use scenarios were evaluated. Potential exposure dose was estimated for all
assumed hypothetical receptors using conservative assumptions about assumed exposure to
constituents in various media. The potential exposure doses estimated in the risk assessment,
combined with estimates of potential assumed toxicity, resulted in estimates of constituent-
specific potential assumed risk to each hypothetical receptor for the various media evaluated.
As described in Section G.1, RBTCLs are calculated based on the potential assumed risks
derived in the risk assessment for each Site use scenario. RBTCLs are presented in the
following sections.
G.2.2 RBTLCs Derived for Commercial/Industrial Site Use
Tables G-2 and G-3 present the RBTCLs (derived assuming degradation occurs) for
commercial/industrial Site use derived for each relevant environmental medium at the Site for
pentachlorophenol and PCDD/PCDFs, respectively. Tables G-2a and G-3a present RBTCLs
derived assuming that degradation does not occur. [RBTCLs are derived, at the request of E:P/\,
assuRling a target Rl3l(iRluRl eimess lifetiRle oanoer risl< of 1 E: 4 (one in ten thousand), 1 E: e (one
in one hundred thousand), and 1 re: G (one in one Rlillion).) Tables G-2 and G-3 present a
comparison of different constituent concentrations with RBTCLs based on the degradation rates
for soil and sediment assumed in the baseline risk assessment, and for RBTCLs derived using
alternate degradation rates for pentachorophenol in soil and sediment. Tables G-2, G-2a, G-3
and G-3a also present the relevant ARARs and other standards for the evaluation of potential
remedial goals at the Site. RBTCLs are derived, at the request of EPA, assuming a target
maximum excess lifetime cancer risk of 1 E-4 (one in ten thousand), 1 E-5 (one in one hundred
thousand), and 1 E-6 (one in one million). A summary of the human health RBTCLs derived
R:\PUBS\PROJECTS\0845008\000.APG G-14 June. 1992
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EN:R
based on future commercial/industrial Site use is presented in this Section; a comparison of
RBTCLs, ARARs and other standards is presented in Section G-4.
RBTCLs for surface soils and subsurface soils at the Site were derived assuming potential
exposure to both the hypothetical maximally exposed Local Off-Site Resident and On-Site
Workers. The On-Site Worker is considered to be potentially exposed to Site soils only. RBTCLs
for all other environmental media are based on potential assumed exposure of the Local Off-Site
Resident.
RBTCLs derived for the Local Off-Site Resident and the On-Site Worker can befafet compared
with existing average, AME and maximum measured constituent concentrations on the tables
in this Section. At the direction of U.S. EPA Region IV, the following sections review the results
of the comparison of RBTCLs for commercial/industrial Site use with existing (average, RME
afl€f.t maximum constituent concentrations in the various media of interest.
G.2.2.1 Surface Soil Results
All RBTCLs derived for surface soil exceed the maximum measured concentrations of
pentachlorophenol and PCOO/PCDF except the following:
• local off-Site resident 1 E-06 RBTCL for pentachlorophenol in Area C derived assuming
alternate degradation rates and assuming no degradation;
• local off-Site resident 1E-04 RBTCLs for PCOO/PCDF in Area C;
• on-Site worker 1E-06 RBTCL for pentachlorophenol in Area C derived assuming
degradation occurs;
• on-Site worker 1E-05 RBTCL for pentachlorophenol in Area C derived assuming no
degradation occurs;
• on-Site worker 1E-06 RBTCL for PCDO/PCOF in Area B derived assuming no
degradation occurs; and
• on-Site worker 1E-04 RBTCLs for PCDD/PCDF in Area C.
This indicates that surface soils in Area C may require remediation.
[All RBTCLs mmept !or those derived !or Area C surlaoe soils, eimeed average, RME and
maid mum oonoenlrations of pentaohlorophenol and PCDD/ PCDF. In Area C, RB TC Ls al the 1 E;
4 and 1 Ee risl1 levels mmeed average, RME and mai(imum oonoenlralions of pentaohlorophenol.
Average oonoenlrations of pentaohlorophonol are below RBTCLs al the 1 E S risk levels assuming
either set of degradation rates. RME oonoenlralions of penlaohlorophenol are below RBTCLs,
R:\PUBS\PROJECTS\084500B\OOO.APG G-15 June, 1992
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but maiEimum eoneentralions eiEeeed RBTGLs at the 1 E 6 le>Jel assuming the degradation rates
used in tho baseline risl1 assessment. RME and maidmum eoneentrations of 13ontaehloro13henol
eiEeoed RBTGLs at the 1 E 6 risk le>Jol assuming the alternate degradation rates evaluated hero.
In !'.rea C surfaee soils, average, RME;, and maJ<imum eonoentrations of PGDD,'PCDF eimeed
RBTGLs at the 1 E 4 risl1 level. This indieales that surfaoe soils in !'.rea C may reeiuire
remediation.)
G.2.2.2 Subsurface Soll Results
{/\>Jerage, RME, and] Maximum concentrations of pentachlorophenol are below RBTCLs in
subsurface soils (from all areas] for commercial/industrial Site use. (!'.>Jerage, RME, and)
Maximum concentrations of PCDD /PCDF are below RB TC Ls at the 1 E-05 risk level in subsurface
soils. [from Areas A, B, and D. RBTGLs al the 1 i;; 4 and 1 E 6 risl< levels derived for Area C f ' subsurfaee soils mmeed a>Jerage, RME, and maJ<imum eonoenlrations of PGDD/PGDF. RBTGLs 1
at the 1 E 6 risl< level mmeed average and RME eonoentralions, but are below maidmum '
!: ,. eoneentrations of PGDD,'PCDF in subsurfaee soil from /\rea G.) Maximum concentrations of
PCDD/PCDF exceed RBTCLs at the tE-06 risk level in Area C subsurface soils. If the Site !
remains commercial/industrial in the future, as is most likely, [remedial goals are lilrnly to be set l
al the 1 E 6 risl< le>Jel. This indieates that ] remediation of subsurface soils is not required based ·
on risk. [ assuming the Sile remains eommereialjinduslrial in the future.)
G.2.2.3 Surface Water Results
[Average, RME, and] Maximum concentrations of pentachlorophenol are below RBTCLs for all I
risk levels for all areas assuming commercial/industrial Site use. [!'.verage, RME;, and) .
Maximum concentrations of PCDD /PCDF are below RBTCLs for the 1 E-4 and 1 E-5 risk levels
in all areas, but these concentrations are above the RBTCL for the 1 E-6 risk level for Fire Pond.
If the Site remains commercial/industrial in the future, as is most likely, [remedial goals are lil1ely
lo be set at the 1 i;; 6 risl1 level. This in di sates that ] remediation of surface water is not likely to
be required based on risk. [ if the Site remains eemmereial/induslrial in the future.]
G.2.2.4 Sediment Results
[Average, RME, and] Maximum concentrations of pentachlorophenol are below RBTCLs for all '·
risk levels for all areas assuming commercial/industrial Site use. [Average, RME, and] !
Maximum concentrations of PCDD/PCDF are below RBTCLs for the 1 E-4 and 1 E-5 risk levels f
in all areas, but these concentrations are above the RBTCL for the 1 E-6 risk level for the I
Discharge Stream from Fire Pond. If the Site remains commercial/industrial in the future, as is •
A:\PUBS\PAOJECTS\0845008\000.APG G-16 June, 1992
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most likely, [remedial goals aro lil<ely to be set at the 1 E: e risk level. This indioates that
tremediation of sediment is not likely to be required based on risk. [ if the Site remains
sommeroial/industrial in the future.)
G.2.2.5 Off-Site Ground Water Results
All concentrations of pentachlorophenol and PCDD/PCDF are below RBTCLs for off-Site ground
water. This indicates that, based on risk, no remediation of off-Site ground water is required at
this Site.
G.2.2.6 Fish Sample Results
Pentachlorophenol was not detected in fish tissue in -fanet any pond of interest. (/\verage,
RME, and] Maximum concentrations of PCDD/PCDF in both Fire Pond and Medlin Pond were
below RBTCLs for the 1 E-4 risk level. [Average, RMe, and] Maximum concentrations of
PCDD/PCDF in Medlin Pond were below RBTCLs at the 1 E-5 risk level. (Average and RMe
sonoentralions of PCDD/PCDF is Medlin Pond were be lo¥.' RBTGLs at the 1 i;; 6 risk level, but)
Maximum concentrations exceed RBTCLs in Medlin Pond at ftllist the 1£-06 risk level.
[Average and RME sonoentralions of PCDD/PCDF in Fire Pond were belo•N RBTCLs at the 1 Ee
risk level, but] Maximum concentrations exceeded RBTCLs in Fire Pond at ftllist the 1 E-05 risk
level. [Average, RMe, and mai<imum sonsentrations of PGDD/PGDF in Fire Pend were abe\le
RBTGLs at the 1 E: 6 risl1 level.) If the Site remains commercial/industrial in the future, as is most
likely, [it is lil<ely that remedial goals will be set at the 1 E e risl< le•,•el, indisating that J remediation
of fish is [lil<ely] not necessary, based on risk.
G.2.3 RBTCLs Derived for Hypothetical Residential Site Use
Tables G-4, G-4a, G-5 and G-5a present the RBTCLs for hypothetical residential Site use derived
for each relevant environmental medium at the Site for pentachlorophenol and PCDD /PCDFs,
respectively. RBTCLs are derived, at the request of EPA, assuming the target is a maximum
excess lifetime cancer risk of 1 E-4 (one in ten thousand), 1 E-5 (one in one hundred thousand),
and 1 E-6 (one in one million). Tables G-4 and G-5 present a comparison of different constituent
concentrations with RBTCLs based on the degradation rates for soil and sediment assumed in
the baseline risk assessment, and for RBTCLs derived using alternate degradation rates for
pentachlorophenol in soil and sediment. As discussed in section G.1.1.2, as requested by U.S.
EPA Region N, Tables G-4a and G-5a present a comparison of different constituent
concentrations with RBTCLs derived assuming degradation does not occur. Tables G-4, G-4a,
G-5 and G-5a also present the relevant ARARs and other standards for the evaluation of potential
remedial goals at the Site. A summary of the human health RBTCLs derived based on future
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residential Site use is presented in this Section; a comparison of the RBTCLs, ARARs and other
standards is presented in Section G-4.
G.2.3.1 Surface Soil Results
Human health RBTCLs derived for surface soil exceed the maximum measured concentrations
of pentachlorophenol and PCDD/PCDF except the following:
• hypothetical on-Site resident 1 E-05 RBTCL for pentachlorophenol in Area C derived
assuming either the degradation rate used in Appendix E, or the alternate degradation
rate;
• hypothetical on-Site resident 1 E-04 RBTCL for pentachforophenol in Area C derived
assuming no degradation occurs;
• hypothetical on-Site resident 1 E-06 RBTCL for PCDD/PCDF in Area a derived assuming
degradation occurs;
• hypothetical on-Site resident 1 E-05 RBTCL for PCDD/PCDF in Area B derived assuming
no degradation occurs; and
• hypothetical on-Site resident 1£-04 RBTCLs for PCDD/PCDF in Area C.
This indicates that remediation of surface soil in Area C may be required if the Site becomes
residential in the future.
(All human health RBTCLs derived for surlaoo soils in /\roas /\, B and D are higher than tho
average, RM!e, and maicimum oonstituent oonoontrations in soil from those areas at tho 1 e: 4 and
1 e e risl1 levels. RBTCLs in Area B surlaoe soil for PCDD/PCDJ; at the 1 E 6 risl1 level are eelow
average, RMe, and maximum oonoentrations, indioating that in the unlil(ely e•,•ent that tho Silo
eeoomes residential in the future, and a remedial goal el 1 E 6 is seleotod, remediation el
PCDD/PCDJ; in Area B surlaoe soil may ee required.
. RBTCLs at the 1 e 4 risl( level !or pentaohlorophenol in Area C surlaoe soil exoeod average, RME,
and maicimum oonoentrations of pontaoholorphenol. RBTCLs at the 1 le e risl1 level derived using
the degradation rates in the easeline risl1 assessment eiweed average, RME, and maicimum
oonoentrations of pentaohlorophenol in Area C surlaoo soil. RBTCLs at the 1 E e risl( le•;el
derived using alternate degradation rates mweed average oonoentrations eut are eelow RME and
maicimum oonoentrations of pentaohlorophenol. RBTCLs at the 1 e 6 risl( 101101 derived using
either degradation rate are eelow average, RM!e, and maieimum oonoentrations el
pentaohlorophenol in Area C surlaoe soil.
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FIBTGLs at all rislc levels fer PGDD/PGDF in Area C surlaoe seil are below average and FIME:
sonoentralions of PGDD/PGDF, indisating that remediation of surlaoe soil in Area C may be
required if the Sile besomes residential in the future.)
G.2.3.2 Subsurface Soil Results
RB TC Ls at the 1 E-4 and 1 E-5 risk levels derived for subsurface soils in Areas A, B and C are
higher than the existing maximum constituent concentrations in these areas, indicating that
remediation is not necessary. RB TC Ls at the 1 E-6 risk level in Area C subsurface soil are higher
than existing concentrations of pentachlorophenol, assuming degradation in the calculation of
RBTCLs, but the maximum concentration of pentachlorophenol is higher than the 1E-06 RBTCL
derived assuming no degradation occurs. The maximum concentrations of PCOD/PCDF in Area
C subsurface soil exceed the 1E-06 RBTCLs for PCDD/PCDF. [and higher than average
oonoenlrations of PGDD/PGDF, but are below FIME: and mrucimum oonsenlralions of
PGDD/PGDF.) This indicates that, if the Site becomes residential in the future, which is unlikely,
and remedial goals are set at the 1 E-6 level, then remediation of PCDD /PCDF in subsurface soil
in Area C may be required based on potential assumed risk.
No RBTCLs are derived in this document for subsurface soil in Area D, because
pentachlorophenol was not detected, and subsurface soils in this area were not analyzed for
PCDD/PCDFs.
G.2.3.3 Surface Water Results
The RBTCLs derived for surface water in the Western Ditch are higher than the existing (average,
FIME, and] maximum constituent concentrations in this area, indicating that no remediation of
surface water in this area is necessary. Further, because the Western Ditch had the highest
constituent concentration of any stream or ditch, and these RBTCLs are applicable to surface
waters in all ditches and discharge streams sampled at the Site, no remediation of any surface
waters in discharge streams and ditches will be necessary.
The existing concentrations of pentachlorophenol in Fire Pond surface water do not exceed the
RBTCLs. (The e>cisling average and FIME: oonoenlralions of PGDD/PGDF in Fire Pond do ROI
e>weed the FIBTGL at the 1 E 4 risl< level; however,] The maximum concentration of PCDD/PCDF
in Fire Pond exceeds the RBTCL at the 1 E-4 risk level. [The average, FIME, and mrncimum
oonoenlrations of PGDD/PGDF in Fire Pond elcoeed the FIBTGLs derived for the 1 E 6 and 1 E: S
risl< levels.] This indicates that remediation of surface water in Fire Pond may be required if the
Site becomes residential in the future. As previously mentioned, this is [very) unlikely.
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G.2.3.4 Sediment Results
The RBTCLs derived for both constituents in sediments in the Western Ditch, which are
applicable to sediments in all discharge streams and ditches, indicate that no remediation of
sediments in these areas is required, because the existing (average, RME, aAd] maximum
constituent concentrations in the Western Ditch do not exceed RBTCLs. The RBTCLs derived
for Fire Pond sediment based on potential assumed exposure to pentachlorophenol exceed
[average, RME, aAd) maximum concentrations indicating no remediation of sediment in Fire
Pond is required based on potential exposure to pentachlorophenol. The RBTCLs at the 1 E-4
and 1 E-5 risk levels derived for Fire Pond sediment based on potential assumed exposure to
PCDD/PCDF exceed (average, RMe, aAd) maximum concentrations indicating no remediation
of sediment in Fire Pond is required. The RBTCLs at the 1 E-6 risk level derived for PCDD /PCDF
in Fire Pond sediment (eicoeeds the aveFage ooAOeAtratioA, but) is below the (RME; aAd)
maximum concentration-fst. This indicates that, if the Site becomes residential in the future,
which is unlikely, and remedial goals are set at the 1 E-6 level, then remediation of PCDD/PCDF
in Fire Pond sediment may be required based on potential assumed risk. ( The poteAlial Reed
lor romediatioA of sedimeAI iA i;:irn PoAd is highly uAlilmly beoause, iA oFder for this aolioA lo be
•NarroAled, first, remedial goals must be set at the 1 i;; G risl< level for PCDD/PCDr, aAd the Sile
must 'oe assumed to 'oeoome resideAtial iA the future.)
G.2.3.5 On-Site Ground water Results
In the Former Lagoon and Eastern Areas, the existing (average, RMe, aAd) maximum
concentrations of pentachlorophenol and PCDD/PCDF in ground water exceed the RBTCLs.
Thus, if the Site is developed for residential use in the future, the Former Lagoon and Eastern
Area ground water may be necessary based on potential assumed risk. Future residential
development is considered unlikely. If the Site remains commercial/industrial, there is no
expected exposure to on-Site ground water and remediation of the on-Site ground water in these
areas is not warranted based on RBTCLs. In some cases, although remediation may not be
required based on assumed risk, recommendations for remediation may be made based on
ARARs or other ractors such as soil clean-up levels for the protection of ground water.
No constituent concentrations in Western Area ground water exceed RBTCLs, indicating that
remediation of ground water in this area would not be necessary based on RBTCLs.
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G.2.3.6 Fish Sample Results
Pentachlorophenol was not detected in fish tissue samples in any pond of interest. For fish fillet
samples from Fire Pond, the [average, RME;, aAd] maximum concentrations of PCDD/PCDFs
are below the RBTCL at the 1 E-4 risk level. For fish fillet samples from Fire Pond, the [ave Fago,
RME, and] maximum concentrations of PCDD/PCDF exceed the RBTCLs at tho 1 E-5 and 1 E-6
risk levels, indicating that, if the Site were to become residential, which is considered unlikely,
a remedial measure restricting use of fish from Fire Pond may be needed.
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EN3l
G.3 Ecological RBTCLs
The previous sections have described the derivation of human health based RBTCLs. This
section presents the procedure to derive ecologically based RBTCLs. Section G.3.1 summarizes
the methodology and results of the ecological risk assessment for the Site. Justification for not
deriving ecological RBTCLs is presented in Section G.3.2.
G.3.1 Review of the Ecological Risk Assessment
The ecological risk assessment was conducted following EPA guidance documents: Risk
Assessment Guidance for Superfund: Volume II. Environmental Evaluation Manual (U.S. EPA.
1989d}. Recommendations for and Documentation of Biological Values for Use in Risk
Assessment (U.S. EPA. 1988a); Quality Criteria for Water. 1986 (U.S. EPA. 1986); Review of
Ecological Risk Assessment Methods (U.S. EPA, 1988b}; and Ecological Assessment at
Hazardous Waste Sites (U.S. EPA, 1989a).
The ecological evaluation includes a habitat characterization. a review of indicator species, a
qualitative evaluation of terrestrial species, and a quantitative evaluation of both aquatic and
riparian species. The methods used to derive potential assumed hazard quotients for aquatic
and riparian species are described below.
G.3.1.1 Aquatic Evaluation
The evaluation of potential assumed exposure of aquatic species to constituents was performed
using the toxicity quotient method prescribed by EPA (U.S. EPA, 1988b. ORNL, 1986). This
method involves the derivation of a toxicity quotient which is the result of a comparison of
surface water constituent concentrations with "benchmark concentrations" for potential assumed
toxicological effects. Therefore, all constituents of interest evaluated in the risk assessment are
reported here. Acute and chronic noncarcinogenic benchmark concentrations were used to
evaluate both potential assumed acute and potential assumed chronic exposures. The
benchmark concentrations used in the risk assessment are ·screening" values provided by EPA
Region IV. Toxicity quotients are classified by EPA as being of 'no concern' if less than 0.1. of
"possible concern" if between 0.1 and 10. and of 'high concern" if greater than 10 (U.S. EPA,
1988b}.
The acute toxicity quotients for each of the constituents in Fire Pond and Medlin Pond were all
less than 0.01 (Table G-6), and fall in the range of "no concern" (U.S. EPA, 1988b}. The results
of the chronic hazard screening evaluation for Fire Pond (Table G-7) indicate that TCDD may
pose "high concern" (toxicity quotient = 17} for aquatic species according to the EPA
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classification criteria (U.S. EPA, 1988b}. The results of the chronic hazard screening evaluation
for Medlin Pond (Table G-7) indicate that TCDD, 2,4,6-trichlorophenol, 2,4-dinitrophenol, 2,3,5,6-
tetrachlorophenol, and 2-methyl-4,6-dinitrophenol may pose "possible concern' for aquatic
species. Note that each of the constituents in Medlin Pond that fall within EPA's range of
'possible concern" are at the extreme low end of this range except for TCDD-TE.
G.3.1.2 Riparian Evaluation
The evaluation of riparian species at the Site follows a method similar to that used to estimate
potential assumed risks to human health. This method involves the application of dose-response
criteria and a series of exposure assumptions to a constituent concentration to derive a hazard
quotient for a given receptor. The ecological receptors evaluated in the risk assessment are
muskrat and belted kingfisher. The muskrat and belted kingfisher were assumed to potentially
be exposed to constituents detected in Fire Pond.
The hazard quotient is calculated using the following equation:
Hazard Ouotient=Estimated Assumed Potential Exposure/Dose-ResponseValue
where: the "estimated potential assumed exposure· is derived from a series of assumptions
about the potential assumed exposure of the receptor to constituents in Fire Pond; and the
"dose-response value" is a species-specific value.
The evaluation indicates that the muskrat's total potential assumed hazard quotient is 0.1. This
is at the very bottom of the EPA's range of "possible concern" (0.1 to 10.0), and represents the
sum of all constituent-specific, potential assumed hazard quotients for the muskrat. The results
of the kingfisher evaluation show that the potential assumed exposure of the kingfisher to TCDD-
TEs leads to an potential assumed hazard quotient of 0.1. This is also at the extreme low end
of the "possible concern" range (0.1 -10.0).
G.3.2 Ecological RBTCLs
The method described in Section G.1 of this evaluation for deriving human health RB TC Ls could
also be used to derive ecological RBTCLs; however, no ecological RBTCLs were derived. The
aquatic screening values are very conservative and are not intended for use in the derivation of
clean-up levels (L. Wellman, 1992). Thus, no ecological RBTCLs are derived from the results of
the aquatic evaluation presented in the risk assessment. However, a further comparison with
other, scientifically defensible, benchmark concentrations was made based on the results of the
comparison with Region IV screening values. Chronic benchmark values were derived for 2,4,6-
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trichlorophenol, 2,4-dinitrophenol, 2,3,5,6-tetrachlorophenol, 2-methyl-4,6-dinitrophenol, and
2,3,7,8-TCDD for constituents in Medlin Pond and for 2,3,7,8-TCDD in Fire Pond. The derivation
of these benchmarks, and the resulting chronic toxicity quotients, is described below.
2,4,6-Trichlorophenol
The Ambient Water Quality Criteria for Chlorinated Phenols (U.S.EPA, 1980a) indicates that the
only freshwater chronic data found were for 2,4,6-trichlorophenol. The species mean acute value
for an early life cycle stage test with fathead minnow was 720 µg/I. EPA Region IV recommends
the application of a safety factor of ten when the data concerning the acute toxicity of a
compound are limited. Applying this safety factor to limited chronic toxicity data would result in
a chronic effects benchmark concentration of 72 µg/I for Medlin Pond and a chronic toxicity
quotient of 0.008. This quotient falls in the range of 'no concern" as defined by EPA (U.S. EPA,
1988b), and thus, no clean-up levels will be calculated for 2,4,6-trichlorophenol.
2,4-Dinitrophenol
The Ambient Water Quality Criteria for Nitrophenols (U.S.EPA, 1980e) indicates that no
freshwater chronic data were found for nitrophenols. The document indicates that toxicity to one
species of algae may occur at concentrations as low as 150 µg/I. EPA Region IV recommends
the application of a safety factor of ten when the data concerning the acute toxicity of a
compound are limited. Applying this safety factor to limited chronic toxicity data would result in
a chronic effects benchmark concentration of 15 µg/ for Medlin Pond and a chronic toxicity
quotient of 0.05. This quotient falls in the range of "no concern· as defined by EPA (ref), and
thus, no clean-up levels will be calculated for 2,4-dinitrophenol.
2,3,5,6-Tetrachlorophenol
The Ambient Water Quality Criteria for Chlorinated Phenols (U.S.EPA, 1980a) indicates that no
freshwater chronic data found were for tetrachlorophenols. Three species mean acute values
were presented. The species mean acute values for 2,3,5,6-tetrachlorophenol with Daphnia
magna and bluegill {Lepomis macrochirus) were 570 µg/I and 170 µg/I, respectively. An
additional acute value of 140 µg/I for the effects of 2,3,4,6-tetrachlorophenol with bluegill was
reported. EPA Region IV recommends the application of a safety factor of ten when the data
concerning the acute toxicity of a compound are limited and the application of an additional
safety factor of ten when extrapolating from acute to chronic effects. This would result in a
chronic effects benchmark concentration of 14 µg/I for Medlin Pond based on 2,3,4,6-
tetrachlorophenol and a chronic toxicity quotient of 0.14. This quotient falls at the extreme low
end of the range of "possible concern" as defined by EPA (1988b) and thus, no clean-up levels
will be calculated for 2,3,5,6-tetrachlorophenol.
2-Methyl-4,6-dinitrophenol
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The Ambient Water Quality Criteria for Nitrophenols (U.S.EPA, 1980e) indicates that no
freshwater chronic data were found for nitrophenols. The document indicates that toxicity to one
species of algae may occur at concentrations of 2-methyl-4,6-dinitrophenol as low as 150 µg/1.
EPA Region IV recommends the application of a safety factor of ten when the data concerning
the acute toxicity of a compound are limited. Applying this safety factor to limited chronic toxicity
data would result in a chronic effects benchmark concentration of 15 µg/I for Medlin Pond and
a chronic toxicity quotient of 0.04. This quotient falls in the range of 'no concern" as defined by
EPA (1988b), and thus, no clean-up levels will be calculated for 2-methyl-4,6-dinitrophenol.
2.3,7,8-TCDD
Two major sources examined for toxicity information on 2,3,7,8-TCDD. The Fish and Wildlife
service "conservatively estimated that water levels of 2,3,7,8-TCDD should not exceed 0.01 ng/I"
(Eisler, 1986). Some of the data upon which this "conservative estimate" is based comes from
24 hour exposures of guppies. A chronic value was also reported from a 96 hour test on
Northern pike embryos. The Ambient Water Quality Criteria for 2,3,7,8-TCDD (U.S. EPA, 1984)
indicates that insufficient freshwater chronic data were available to calculate a chronic criterion.
The EPA also reviewed the information used as the basis of the Fish and Wildlife Service report
including the 96 hour test on Northern pike embryos that indicated a 'slight reduction in growth
up to 21 days." The criteria document concluded that "the available information indicates that
acute values for some freshwater animal species are greater than 1.0 µg/I; some chronic values
are less than 0.1 µg/I, and the chronic value for rainbow trout is less than 0.001 µg/I" (U.S.EPA,
1984). EPA Region IV recommends the application of a safety factor of ten when the data
concerning the acute toxicity of a compound are limited. Applying this safety factor to the limited
chronic toxicity data reported for rainbow trout would result in a chronic effects benchmark
concentration of 0.0001 µg/I for Fire Pond and Medlin Pond and chronic toxicity quotients of
1.65 and 0.12, respectively. These quotients fall at the low end of the range of "possible
concern' as defined by EPA (U.S. EPA, 1988b). Specific methodologies exist for determining
clean-up levels for human health based on allowable risk levels. Similar specific guidance is not
available for aquatic receptors, thus, no RBTCLs are derived for aquatic receptors. However, the
calculated clean-up levels designed to be protective for human health (Section G.2) will result
in a ten-fold reduction in surface water concentrations of TCDD-TE. These levels will be
protective of aquatic receptors with an estimated Fire Pond toxicity quotient of 0.165 and Medlin
Pond toxicity quotient of 0.012.
The muskrat evaluation indicated a total potential assumed hazard quotient equal to 0.1.
[Thus.] Each constituent-specific hazard quotient is less than 0.1, or of "no concern". Because
the estimated exposure to fallt each constituentfst results in an potential assumed hazard
quotient considered to be of "no concern". no RBTCLs were calculated for the muskrat.
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Similarly, the potential assumed hazard quotient for the kingfisher for TCDD-TE is 0.1 which also
does not exceed the threshold of "possible concern'. Thus, no ecological RBTCLs were derived for the kingfisher. The results of both of these evaluations indicate that remediation is not
necessary to protect riparian ecological receptors.
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G.4 Comparison of ARARs and RBTCLs
This section presents a comparison of existing constituent concentrations in various media with
RBTCLs derived in Section G.2, State of North Carolina and federal ARARs, and soil target clean-
up levels derived for the protection of ground water. When remediation goals for media or areas
of the Site are considered, the RBTCLs and all applicable standards can be compared in order
to determine the most reasonable and appropriate remediation measures to pursue.
The relevant ARARs identified for the constituents of interest in this document are North Carolina
standards and federal MCLs for pentachlorophenol and 2,3,7,8-TCDD. Soil target clean-up levels
for the protection of ground water have also been derived for pentachlorophenol and 2,3,7,8-
TCDD (KER, 1992a).
Tables G-2, G-2a, G-3 and G-3a present a comparison of ARARs and RBTCLs derived for the
commercial/industrial Site use scenarios for pentachlorophenol and PCDD/PCDF, respectively.
Tables G-4, G-4a, G-5 and G-5a present a comparison of ARARs and RBTCLs derived for the
hypothetical future residential Site use scenarios for pentachlorophenol and PCDD /PCDF,
respectively. The existing average, RME, and maximum constituent concentrations are
presented here for comparison with RBTCLs and ARARs. As discussed in Section G-1, Beazer
East, Inc. feels the comparison of RBTCLs and ARARs with average values is appropriate for
setting remedial goals because of the many conservative assumptions used to derive the
RBTCLs. However, at the request of EPA, comparison of RBTCLs and ARARs with [RMI= and]
maximum values is the focus of this evaluation. [also presented.] In addition, the model used
to derive soil target clean-up levels for the protection of ground water requires comparison of
resulting target levels with maximum constituent concentrations in soil.
Section G.4.1 describes the comparison of the derived RBTCLs for soil with the appropriate
standards. Section G.4.2 describes the comparison of RBTCLs derived in this document for
surface water with the appropriate standards. Section G.4.3 describes the comparison of
RBTCLs derived in this document for sediment with the appropriate values. Section G.4.4-f3t
describes the comparison of RBTCLs derived in this document for ground water with the
appropriate standards. Section G.4.5-f4+ reviews the findings of the fish analysis presented in
Section G.2. {All constituent concentrations in sediment were below RBTGLs and there are no
ARARs !or sediment, indicating that no remediation ol sediment is requireel. Therelore sediment
is AO! eliSOlJSSed lllrther iA this e1,allJation.J
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G.4.1 Comparison of SoH RBTCLs and ARARs
Soil target clean-up levels for the protection of ground water were derived for pentachlorophenol
and 2,3,7,8-TCDD in a separate report (KER, 1992a). Section G.4.1.1 reviews the results of the comparison of concentrations of constituents with soil target clean-up levels for the protection
of ground water and RBTCLs derived for soil in the commercial/industrial Site use scenario. Section G.4.1.2 reviews the results of the comparison of constituent concentrations with soil target clean-up levels for the protection of ground water and RBTCLs derived for soil in the
residential Site use scenario.
G.4.1.1 Commercial/Industrial Site Use Results
In surface and subsurface soils in Areas A, B, and D, the existing [average, RMe, and] maximum concentrations of constituents are lower than the RBTCLs (except the 1 E-06 RBTCL for Area B PCDD/PCDF assuming no degradation occurs), and the maximum concentrations of constituents are lower than the ground water protection soil target levels. Thus, based on RBTCLs and protection of ground water, no remediation of soils is likely to be required in any of these areas.
Tho Area C [average, RMe, and] maximum concentrations of pentachlorophenol in surface and subsurface soil are below the RBTCLs at the 1 E-5 risk level, indicating that no remediation is [needed] likely to be required based on human exposure to soil. The maximum concentration
of pentachlorophenol in Area C surface soil (3200 ppm) and subsurface soil (560 ppm), however, exceeds the soil target level for the protection of ground water (95 ppm). This indicates that remediation of both surface and subsurface soil may be required for the protection of ground water.
The [a·,orage, RMe, and] maximum concentrations of PCDD/PCDFs found in Area C surface soil exceed the human health RBTCLs and the ground water protection soil target clean-up level, indicating that remediation may be required for Area C surface soils. Concentrations of PCDD/PCDF in Area C subsurface soil are below RBTCLs at the 1 E-5 risk level, and ground
water protection values, indicating no need for remediation of subsurface soils based on PCDD/PCDF.
G.4.1.2 Residential Site Use Results
The maximum concentrations of pentachlorophenol in Areas A, B and D soils are below the RBTCLs for residential Site use. Areas A and D were not analyzed for PCDD/PCDF in surface or subsurface soil. The maximum concentrations of PCDD/PCDF in Area B surface soil exceed
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the RBTCL at the 1 E-6 risk level derived assuming degradation, and the RBTCL at the 1 E-5 risk
level derived assuming no degradation occurs. The maximum constituent concentrations in
Areas A, B and D soils do not exceed the soil target clean-up levels for the protection of ground
water indicating that remediation of soils in these areas is likely not to be required based on risk.
The maximum concentration of pentachlorophenol in Area C surface soil exceeds the RBTCLs
at the 1 E-5 risk level derived assuming degradation occurs, and the RBTCL at the 1 E-4 risk level
derived assuming degradation does not occur. The maximum concentration of
pentachlorophenol in Area C subsurface soil exceeds only the RBTCL at the 1 E-6 risk level
derived assuming no degradation occurs. [ Average, RMe, and maiEimum constituent
concentrations in surface and subsurface soil in Areas A, B and D are below RBTCLs at the 1 e e
risl< level, and the ground water proteotion soil target olean up levels. Thus, remediation of Areas
A, B and D soils is not indioated even in the unlilwl~· event that the Site were to besoms
residential.
The ,0,rea C average oonoentration of pentaohlorophenol in surfaoe and subsurfaoe soil is below
the RBTCL at the 1 e e risl< level, and the RMe and maximum conoentrations eimeed only the
RBTCL derived using alternate degradation rates, indioating that no remediation is needed based
on potential assumed human exposure to pentaohlorophenol in soil.) The maximum
concentration of pentachlorophenol in Area C surface soil (3200 ppm) and subsurface soil (560
ppm), however, exceeds the soil target level for the protection of ground water (95 ppm). This
indicates that both surface and subsurface soil may be required for the protection of ground
water.
The [average, RMe, and) maximum concentration-ts+ of PCDD/PCDF in Area C surface soils
exceeds the RBTCL, and the maximum concentration in Area C surface soil exceeds the ground
water protection soil target clean-up level. Thus, remediation may be required for Area C surface
soils. However, the lowest RBTCL ( [0.0001 J 5E-06 ppm) for PCDD/PCDFs in surface soil is
greater than two orders of magnitude smaller [ten times lower) than the frequently used surface
soil clean-up level of 0.001 ppm. Because of the precedent of using this target clean-up level,
it is likely that it, or the value for the protection of ground water, would be given preference here
over the RBTCL (at the 1E-06 risk level, assuming degradation does not occur and assuming
future residential Site use) for residential Site use.
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G.4.2 Comparison of Surface Water RBTCLs and ARARs
The surface water bodies evaluated here include Fire Pond, Medlin Pond, and the Western Ditch.
The North Carolina surface water standard for 2,3,7,8-TCDD is 1.3E-11 ppm (or 0.013 ppq). The
isomer 2,3,7,8 TCDD was not detected in any surface water samples on the Site. Most of the
PCDD/PCDFs in surface water at the Site were 'octa" congeners. The State standard is for
2,3,7,8-TCDD in surface water. Because the State standard is driven almost exclusively by
consumption of 2,3,7,B-TCDD that has bioaccumulated in fish, this standard is not applicable to
congeners other than 2,3,7,8-TCDD unless an adjustment for bioaccumulation is also made. If
the State standard were adjusted to reflect the differences in bioaccumulation of the congeners
detected in surface water on the Site, it would likely increase by several orders of magnitude.
Because the State standard is not considered appropriate for comparison with concentrations
of PCDD/PCDF found at this Site, it is not addressed further in this evaluation. It is also
important to note, however, that not only is the State standard considered inappropriate, but it
is also not achievable because it is well below the laboratory detection limit for 2,3,7,8-TCDD.
Section G.4.2.1 reviews the results of the comparison of constituent concentrations with RBTCLs
derived for the commercial/industrial Site use scenario. Section G.4.2.2 reviews the results of
the comparison of constituent concentrations with RBTCLs derived for the residential Site use
scenario.
G.4.2.1 Commercial/Industrial Site Use Results
All constituent concentrations in surface water bodies evaluated here are less than the RBTCLs
at the 1 E-5 risk level derived for commercial/industrial Site use. Maximum measured
concentrations exceed RBTCLs at the 1E-06 risk level for PCDD/PCDF in Fire Pond surface
water. Thus, no remediation of surface water is likely to be required if the Site remains
commercial/industrial in the future.
G.4.2.2 Residential Site Use Results
In the residential Site use evaluation, [all average, RME, and] maximum concentrations of
pentachlorophenol and PCDD/PCDF in surface water, except PCDD/PCDF in Fire Pond, are
lower than RBTCLs at the 1 E-6-fet risk level. This suggests that remediation of surface water
is not likely to be required for [Modlin Pond or] the Western Ditch.
The (average, RMe, and] maximum PCDD/PCDF concentrations in Fire Pond exceed the
RBTCLs at the 1 E-4-fet risk level for residential Site use. In the unlikely event that the Site is
developed for residential use in tho future, Fire Pond surface water may require remediation.
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G.4.3 Comparison of Sediment RBTCLs
There are no ARARs for the constituents of interest in sediment. Comparison of maximum
measured sediment concentrations of pentachlorophenol with RBTCLs indicates no remediation
is required based on assumed risk. Comparison of maximum measured sediment concentrations
of dioxin with RBTCLs indicates remediation of sediment in the Fire Pond Discharge Stream may
be required if 1 E-06 is selected as the remedial risk goal for commercial/industrial Site use.
Remediation of Fire Pond sediment may also be required if 1 E-06 is selected as the remedial
goal for residential Site use. It is unlikely that the Site will be developed for residential use in the
future based on current development in the area near the Site and the fact that an active
commercial/industrial facility currently operates on the Site.
G.4.4 Comparison of Ground Water RBTCLs and ARARs
Ground water was sampled off-Site and in three on-Site areas: the Former Lagoon Area, the
Eastern Area and the Western Area. The off-Site analysis was prepared for the
commercial/industrial Site use scenario which assumes that future off-site residents consume
off-site ground water as drinking water. [eeoause, in this situation, no oensurnption of on Site
ground water would ooour.] The results of the comparison of RBTCLs and ARARs for off-Site
ground water assuming future commercial/industrial Site use is presented in Section G.4.3.1.
The on-Site analysis was prepared for the future residential Site use scenario because this leads
to the most health-protective result. Section G.4.4.2 presents the results of the comparison of
RBTCLs and ARARs for on-Site ground water assuming the Site is developed for residential use.
G.4.4.1 Commercial/Industrial Site Use Results
The [average, RMe, and] maximum concentrations of pentachlorophenol in off-Site ground
water are well below the RBTCL and the MCL. Thus, no remediation of pentachlorophenol in
off-Site ground water is required on the basis of either potential human health effects or to meet
appropriate ground water ARARs for pentachlorophenol.
Both a North Carolina Ground Water Standard and -farita proposed MCL exist for 2,3,7,8-TCDD.
These standards can be compared with the Local Off-Site Resident RBTCL for ground water.
The [average, RM.O, and] maximum concentrations of PCDD/PCDFs in off-Site ground water
are below the RBTCL, the proposed MCL and the North Carolina Ground water Standard. Thus,
no remediation of PCDD /PCDFs in off-Site ground water is required on the basis of RBTCLs or
ARARs.
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G.4.4.2 Residential Site Use Results
On-Site ground water was evaluated for the hypothetical residential future use scenario. The
results of the comparison of Former Lagoon and Eastern Area constituent concentrations with
RBTCLs and ARARs are presented below. No constituent concentrations exceeded RBTCLs or
ARARs in the Western Area. Therefore, the Western Area is not discussed further in this
evaluation.
Former Lagoon Area Results
Tho [average, RMI;;, and] maximum concentrations of pentachlorophenol in the Former Lagoon
Area exceed the RBTCLs and the MCL. These results suggest that remediation of
pentachlorophenol may be required in the Former Lagoon Area.
I
The [average, RMI;; and) maximum concentrations of PCDD/PCDF in tho (l;;astorn) Former I
Lagoon Area exceed the RBTCLs, State standard, and the proposed MCL, indicating that
remediation of PCDD/PCDF may be required in the Former Lagoon Area.
Eastern Area Results
[The ffioan oonoentration of pentaohlorophenol in the Eastern Area e>meods the MCL, and is
equal to tho RBTGL.] The [RME: and] maximum concentration-f&t of pentachlorophenol in the
Eastern Area exceeds the MCL and the RBTCL. These results suggest that remediation of
pentachlorophenol may be required in the Eastern Area.
The [ffiean, RMI;;, and] maximum concentration-f&t of PCDD/PCDF in Eastern Area ground
water is -faffi}-higher than the RBTCL, the State standard and the proposed MCL. Thus,
remediation of Eastern Area ground water may be required at this Site.
G.4.5 Comparison of Fish RBTCLs and Existing Concentrations
There are no ARARs for the constituents of interest available for the evaluation of fish tissue.
Pentachlorophenol was not detected in fish tissue in either Fire Pond or Medlin Pond. [The only
oonsliluont evaluated in fish tissue that eicoeedod the RBTGL (at the 1 E: e risl1 level) was
PGDD/PGDF in Fire Pond in the future residential scenario.) The maximum [average and
RM!;}-concentration [s for] of PCDD/PCDF in fish tissue in [both] Fire Pond [and Medlin Pond]
in tho commercial/industrial scenario exceeds the [were below the] RBTCL-f&t at the 1 E-5 risk
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level for PCDD/PCDF in fish tissue. The maximum concentration of PCDD 1PCDF in fish tissue ,
in Medlin Pond in the commercial/industrial scenario exceeds the RBTCL ~; the 1 E-6 risk level. j
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[however, the mai<imum oonoentration of PGDD/PGDF in fish from Fire Pond in this soenario
ei1eeeded the RBTGL at the 1 E e risl< level.] The maximum concentration of PCDD/PCDF
exceeds the RBTCL in Fire Pond at the 1 E-5 risk level in the future residential site use scenario.
If the Site is developed for residential use in the future, some action restricting consumption of
fish from Fire Pond may be required.
G.5 Summary and Conclusions
This Appendix has derived RBTCLs for the former Koppers Company, Inc. Site in Morrisville,
North Carolina. These RBTCLs are based upon potential assumed carcinogenic risks to human
receptors assuming two different future potential Site use conditions. The human health RBTCLs
were determined using the potential assumed carcinogenic risks estimated in the risk
assessment for this Site, which was conducted following EPA guidance and in accordance with
standard risk assessment methodology. Parallel analyses for ecological receptors suggest that remedial action is not necessary and, therefore, RBTCLs are not required for ecological
receptors.
As discussed in Section G.1, remediation decisions should be based on the comparison of average constituent concentrations, not upper-bound concentrations, because of the inherent
conservatism built into the process. However, at the request of EPA, comparisons were made
with [average, RME, QBQJ_] maximum constituent concentrations. It is important to note,
however, that, in most cases, use of the average constituent concentration instead of the~ e4 maximum concentration does not change the recommendations made here.
This Section is divided into four sub-sections. Section G.5.1 presents a summary of the RBTCLs derived in this evaluation. [Seotion G.e.2 proposes a remediation strategy for the Sile and
desoribes the implementation of the RBTCls in that strategy.] Section G.5.2-{at summarizes
the comparison of constituent concentrations in various media with RBTCLs and ARARs available
for those constituents. Section G.5.3f4t presents a summary of the findings in this evaluation.
G.5.1 Summary of Human Health RBTCLs
The human health RBTCLs derived in Section G.2 indicate that, based on potential assumed risks, few environmental media and few areas of the Site may require remediation. The following
areas [possibly requiring remediation are: J have maximum constituent concentrations that exceed
RBTCLs at the 1 E-04, 1 E-05 or 1 E-06 risk levels in either or both potential future site use
scenarios:
• surface soil Area B (dioxin at 1 E-06 for commercial/industrial use;
dioxin at 1 E-05 for residential use);
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EN3l
• surface soil Area C (pentachlorophenol at 1 E-05 for commercial/industrial use;
pentachlorophenol at 1 E-04 for residential use; dioxin at 1 E-04 for commercial/industrial
use and residential use);
• subsurface soil Area C (pentachlorophenol at 1 E-06 for residential use; dioxin at 1 E-06
for commercial/industrial use and residenual use);
• surface water in Fire Pond (dioxin at 1 E-06 for commercial/industrial use; dioxin at 1 E-
04 for residential use);
• sediment in Fire Pond Discharge Stream (dioxin at 1 E-06 for commercial/industrial use);
• sediment in Fire Pond (dioxin at 1 E-06 for residential use);
• on-Site ground water in the Eastern Area (pentachlorophenol at 1£-05 and dioxin at 1£-
04 for residential use);
• on-Site ground water in the Former Lagoon Area (pentachloropheno/ at 1 E-04 and dioxin
at 1£-04 for residential use);
• fish in Fire Pond (dioxin at 1 E-05 for commercial/industrial and residential use); and
• fish in Medlin Pond (dioxin at 1 E-06 for commercial/industrial use).
Because the Site is likely to remain commercial/industrial in the future, remediation at this Site
(based on risk) may be required in the following areas:
• surface soil in Area C;
• on-Site ground water in the Former Lagoon and the Eastern Area (based on MC Ls); and
• fish from Fire Pond.
These areas were those in which the potential assumed carcinogenic risk estimated in the risk
assessment was greater than 1 E-5 for one or more of the hypothetical potential receptors, or the
RBTCLs derived were substantially lower than the existing constituent concentrations.
[G e.2 Remediation Strategy: Implementation of RBTGLs
Soolion G.1 diso1cJssed how lo derive and 1cJse RBTGLs to determine whether en1Jironmenlal
media on a site need remedial aolion. The prooedllro led to site spooifio piol< llp levels whioh
targeted remediation of the areas of the site with the highest oonslit1cJent oonoentrations, bllt left
1cJnto1cJohod tho areas below the piol< llp level even thollgh few of these remaining areas may be
above Iha RBTGL. This proood1cJre ons1cJred that the ros1cJlting average oonoentralions wo1cJld be
proloolive of a hypothotioal roocplor who is assllmcd lo potentially oontaol environmental media
on the site over !he C><pos1cJrc d1cJralion assw'fled by !he baseline risl< assessment.
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Table G 8 shows !he applioalion of !he most oonscrvalivc oommcroial/ind1cJslrial RBTGL dcri>Jod \
in Scotian G.2 for Arca C for PGDD/PGDF (0.01 ppm). Bcoallso ii is Iha most stringent RBTGL l
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lor this area anel scenario, it also protests tho Local Off Sito Rosielont trespasser (13asoel on tho
Local Off Sito Resident RBTCL of 0.04 ppm) as well as grounel waler (eased on tho soil 101101
eorivod for protection of ground water, 0.007 ppm). Tho "piol< up level" in this ease would
olfootivoly 80 all soils that GUFF0Ally have a PCDDf PCDF GOAG0AlratioA of 0.27 ppm OF higher.
Romeeiation of soils asovo this "piol< up" level would loa•,o tho remaining soils on tho site with
a PCDD,'PCDF G0A00AtratiOA of 0.001 ppm, woll 13olow tho RBTGL of 0.01 ppm, as SODA iA Tasia
G-&,
Target surtaoo soil olean up levels for PCDD/PCDF at residential sites are rarely 13olow 1 ppl3
( 0.001ppm). Beoauso tho future residential use soenario is unlil<oly, tho proposed RBTCL of
0.01 ppm, derived eased on future oommoroialfindustrial Sito use, is rooommondod as providing
adequate proteotion under all lil<ely Silo uses.
II tho remediation dooisions at this Silo wore eased only on assumed risl< from exposure to soil,
tho only oonstituont in soil that may require remediation is PCDD/PGDF. If this wore tho ease,
only sample X 48 (0.27 ppm) would need to so 'piol1od up' eased on a comparison ol average
oonoontrations. In mdor to also protoot grnund water from mmooding MCLs, however, aooording
to tho model ohosen to derive soil oloan up lo,•els for the protootion of ground •,valor,
oonoentratiOAS of OOASlilU0AIS iA soil oimoediAg the soil Olean up level for tho proteotioA of ground water would also need to so "piol10d up." Only one PCDD/PCDF sample (sample X 48,
0.3 ppm) oimoeds tho soil level /or proteotion of ground water (0.007 ppm). Thus, 13asoe on
assumed risl< and ground water protootion for PGDD/PCDF, only one soil sample at the Sito may rnquiro remediation. This is not tho ease for pontaohlorophonol, howo·,or. Tho Area G average
oonoontration el pontaohlorophonol eloes not oxoooel tho RBTCLs.
Thus, eased on assumed risk from eiEposure to pontaohlorophenol in /\roa C soil, no remediation
is needed. IA order to protoot ground water, howe,•or, several soil samples iA area C surlaoo and
sussurlaoe soil may require remediation. As shown on Tal3Ie G 9, pontaohlorophenol in lour
surlaoo soil samples oiwoods tho soil level for tho protootion el ground ,..,.ator (9e ppm). P,s
shown in Tasia G 10, pentaohlorophonol in two sussurlaoe soil samples oiEoooels the soil level
for tho protection ol ground water. Thus, eased on protection of ground water for
pentaohlorophonol, four surface and two sul3surlaoo soil samples at tho Sito may require
remediation.
After samples that may require remediation have seen identified eased on 130th PCDD/PCDF
and pentaohlorophonol, a remediation strategy for Area C soils must so determined. Based
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upoA the historioal operatioAs of the Koppers faoility OR the Site, it is possible that the ooourreAoe
a Ad OOAOOAlralioA of peAtaohloropheAol a Ad PGDD/ PGDF iA surlaoe soils are 00 looated. IA
other words, the looalioA 1.vilh the highest OOAOeAlratioA of PGDD/PGDF may also have the
highest ooAoeAtratioA of peAtaohloropheAol. The sample results ooAfirm this. SiAoe this is the
ease, remediatiAg surtaoo soils to aohieve remedial goals for peAtaohloropheAol will also result
iA the aohievemeAt of the PGDD/PGDF surlaoe soil remedial goals. WheA the surtaoe soil
samples iA Area C are raAlrnd based upoA peAtaohloropheAol ooAoeAlratioA (Table G 9), aAd
the A those samples with ooAoeAtralioAs eimeediAg the remediatioA goal of Q§ ppm are assumed
to be remediated, the soil samples with the two highest PGDD/PGDF ooAoeAtralioAs are also
remediated. As has beeA showA above (Table G 8), removal of just the soil sample with the
highest PGDD/PGDF OOAOeAtratioA results iA aohievemeAt of the RBTGL reoommeAded iA this
evaluatioA. Clearly, removal of surtaoe soils with the two highest PGDD/PGDF ooAoeAlralioAs
would AO! ORiy aohieve the RBTGL but provide additiOAal proleolioA.
As a result of this aAalysis, ii is appareAI that trealiAg the remediatioA of peAlaohloropheAol aAd
PGDD/ PGDF separately is UAAeoessary. FooussiAg the remediatioA strategy OR remedialiAg
surtaoe soils iA /\rea C suoh that 9§ ppm is Rot mmeeded for peAlaohloropheAol, will also result
iA aohievemeAt of the RBTGL aAd the soil level for proleolioA of grouAd water for PGDD/PGDF.
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G.5.2 Summary of Comparison of ARARs and RBTCLs
The following sections summarize the results of the comparison of RBTCLs, ARARs and
guidelines with existing maximum constituent concentrations in the various media investigated
in the baseline risk assessment. Table G-8 [G 11) identifies the media and areas that may
require remediation, and summarizes the [reoommeAded] remedial goals recommended by
Beazer East, Inc. for this Site.
G.5.2.1 Soil Summary
The results of the comparison of constituent concentrations with RB TC Ls and relevant guidelines
indicates that only soil in Area C may require remediation. The potential need for remediation
in Area C surface and subsurface soils is supported by the results of the analysis of
pentachlorophenol in assumed future use scenarios; the maximum surface and subsurface soil
concentrations (3200 ppm and 560 ppm, respectively) exceed the soil level derived for the
protection of ground water (95 pm) and some of the relevant RBTCLs.
The potential need for remediation in Area C surface soils is also supported by the results of
both the commercial/industrial Site use and residential Site use analyses of PCDD/PCDF. In
both assumed future Site use scenarios, [tho RMe ooAoenlralion of PGDD/PGDF in surtaoe soil
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(-0.2 ppm) and) the maximum concentration of PCDD/PCDF in surface soil (0.27 ppm) exceeds
the RBTCLs derived for the receptors at various risk levels [(On Sito Worl~or 0.001 ppm, and
hypothetical On Sito Resident 0.0001 ppm)] and the soil target clean-up level for protection
of ground water (0.007 ppm). Subsurface soil in Area C does not require remediation based on
PCDD/PCDF because, in all scenarios, (average, RME;, and) maximum concentrations of
PCDD/PCDF are below RBTCLs and soil levels for the protection of ground water. (Section
G.6.2. i:iresenls a strategy for applying RBTCLs in Area C surface soil, and demonstrates that a
remediation effort based on i:iroteclion of ground water for pentachlorophenol will also result in
aohiovement of the RBTCL and ground 11,•ator protection for PCDD/PCDF.)
G.5.2.2 Surface Water Summary
As discussed in Section G.4.2, the State standard for 2,3,7,8-TCDD is not considered applicable
at this Site. In this analysis, constituents in surface water in Fire Pond, Medlin Pond, and in the
Western Ditch were compared with RBTCLs. The results of these analyses show that only the
Fire Pond may require remediation if the Site becomes residential in the future [(RME and
maiEimum PCDD/PCDF conoentrations 2i;; 7 ppm, RBTGL 2E 8 ppm)). If the Site remains
commercial/industrial, as is more likely, no surface water remediation is required based on the
RBTCLs derived here.
G.5.2.3 Ground water Summary
Ground water was evaluated off-Site and on-Site. Pentachlorophenol and PCDD/PCDF
concentrations in several ground water areas of interest exceeded RBTCLs and other ARARs.
The results of the off-Site ground water and on-Site ground water analyses are presented below.
Off-Site Summary
The (average, RME;, and) maximum concentrations of both pentachlorophenol and PCDD/PCDF
are less than the most conservative of either the RBTCL or ARAR for that constituent in ground
water. Because no one currently has access to off-Site ground water for drinking water, and no
one is expected to in the foreseeable future, and because no existing concentrations exceed
RBTCLs or ARARs, no remediation of off-Site ground water is required.
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On-Site Summary
Two on-Site ground water areas may require remediation based on potential assumed risk only
if the Site becomes residential in the future: the Former Lagoon Area and Eastern Area. For this
hypothetical future use scenario, tho (RME oonoentration of pentaohlorophenol (0.35 ppm) ana tf1ot maximum concentration of pentachlorophenol in the Former Lagoon Area (1.49 ppm)
exceeds both the MCL (0.001 ppm) and the RBTCL..s [(0.004 ppm)). This indicates that
remediation of Former Lagoon Area ground water may be required.
The [RME oonoentration of PCDD/PCDF (SE 8 ppm) ana the] maximum concentration of
PCDD /PCDF (8E-8 ppm) in the Former Lagoon Area exceeds the RBTCL..s [ {3E 9 ppm)], the
proposed MCL (5E-8 ppm), and the State standard (2E-10 ppm) for dioxin. These data also
indicate that remediation of Former Lagoon Area ground water may be required. Although the
State standard for dioxin is lower than the MCL, it may be appropriate to set the remediation
goal for dioxin at the MCL because exposure to on-Site ground water as a drinking water source
is extremely unlikely, and the MCL is considered protective by the EPA.
In Eastern Area ground water, the [RME oonoentralion of penlaohlorophonol {0.01 ppm) ana tflot maximum concentration of pentachlorophenol (0.05 ppm) exceeds the RBTCL (0.004 ppm)
and the MCL (0.001 ppm). The [RME and] maximum concentrationfst of PCDD/PCDF in
Eastern Area ground water (2E-7 ppm) also exceeds the RBTCL..s [{3E 9 ppm)], the proposed
MCL (5E-8 ppm) and the State standard (2E-10 ppm), indicating that remediation may be
required. As stated above, the MCL is the [roeornrnondea] clean-up goal recommended by
Beazer East, Inc. for ground water at this Site.
G.5.2.4 Fish Summary
The [RME ana] maximum concentrationfst of PCDD/PCDF in fish from Fire Pond (4E-5 ppm)
exceeds the RBTCL..s at the 1E-05 and 1E-06 risk levels (5E-6 ppm and 5E-7 ppm). This indicates
that a remedial measure restricting use of fish from Fire Pond may be needed.
G.5.3 Clean-Up Levels Evaluation Summary
Based on a comparison of existing maximum concentrations of pentachlorophenol and
PCDD/PCDF with human health RBTCLs, ARARs and other clean-up guidelines, the following
media may require remediation at the Former Koppers Company, Inc. Site in Morrisville, NC:
• surface and subsurface soil in Area C;
• surface water in Fire Pond (residential Site use only);
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• on-Site ground water in the Former Lagoon and Eastern Areas; and
• fish from Fire Pond.
Table G-8 [G 11] presents a summary of the remedial goals presented in this evaluation. As I
shown on this table, if the Site remains commercial/industrial, which is most likely, only
remediation of surface and subsurface soil in Area C, on-Site ground water in the Former Lagoon
and Eastern Areas (to meet MC Ls), and fish in Fire Pond, may be required. If the Site becomes
residential, which is unlikely, surface water from Fire Pond may also require remediation action.
The recommendations made in this appendix were derived from many conservative assumptions
and, thus, are health protective. Many of the RBTCLs derived here are based on the
assumptions that the Site is developed for residential use in the future. Because it is unlikely that
the Site will become residential, RBTCLs derived for residential use are not appropriate for this
Site.
A:\PUBS\PAOJECTS\0845008\000.APG G-39 June, 1992
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REFERENCES FOR APPENDIX G
Anderson, E., N. Browne, S. Duletsky, J. Tamig and T. Warn. 1985. Development of Statistical
Distributions for Ranges of Standard Factors Used in Exposure Assessments. Office of
Health and Environmental Assessment. EPA/600/8-85/010, Washington, D.C.
Eisler, R. 1986. Dioxin Hazards to Fish, Wildlife, and Invertebrates: A Synoptic Review.
Biological Report 85 (1.8) U.S. Fish and Wildlife Service. Laurel, MD.
Keystone Environmental Resources, Inc. (KER) 1992a. "Development of Soil Clean-up Goals
Protective of Groundwater Quality." Former Koppers Company, Inc. Superfund Site,
Morrisville, NC. December 1991.
Keystone Environmental Resources, Inc. (KER) 1992b. Remedial Investigation Draft Report,
Former Koppers Company, Inc. Superfund Site, Morrisville, North Carolina. June 1991.
Koporec, K. 1991. U.S. EPA Region IV. Personal Communication, April 23, 1991.
Oak Ridge National Laboratory (ORNL). 1986. User's Manual for Ecological Risk Assessment.
Rupp, E.M., F.L. Miller and C.F. Baes Ill. 1980. Some Results of Recent Surveys of Fish and
Shellfish Consumption by Age and Region of U.S. Residents. Health Physics 39: 165-175.
State of North Carolina (NC DNRCD). 1989. 1987 Ambient Air Quality. Department of Natural
Resources and Community Development, Division of Environmental Management. May
1989.
U.S. EPA. 1980. Dietary Consumption Distribution of Selected Food Groups for the U.S.
Population. Office of Pesticides and Toxic Substances. EPA 560/11-80/012.
U.S. EPA. 1986. Quality Criteria for Water. 1986. Office of Water Regulations and Standards.
EPA 440/5-86/001.
U.S. EPA. 1988a. Recommendations for and Documentation of Biological Values for Use in
Risk Assessment. Office of Research and Development, Cincinnati, OH. PB88-179874.
U.S. EPA. 1988b. Review of Ecological Risk Assessment Methods. EPA/230/10-88/041.
U.S. EPA. 1988c. Superfund Exposure Assessment Manual. Office of Emergency and
Remedial Response, Washington, D.C. EPA/540/1-88/001.
U.S. EPA. 1989a. Ecological Assessment at Hazardous Waste Sites: A Field and Laboratory
Reference. EPA/600-3-89/013.
U.S. EPA. 1989b. Exposure Factors Handbook. Office of Health and Environmental
Assessment, Washington, D.C. EPA/600/8-89/043.
R:\PUBS\PROJECTS\0845008\000.APG G-40 June. 1992
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EN3t
U.S. EPA. 1989c. Risk Assessment Guidance for Superfund. Volume I: Human Health
Evaluation Manual (Part A). Interim Final. Office of Emergency and Remedial Response,
Washington, D.C. EPA 540/1-89/002.
U.S. EPA. 1989d. Risk Assessment Guidance for Superfund. Volume II: Environmental
Evaluation Manual (Part 8). Interim Final. Office of Emergency and Remedial Response,
Washington D.C. EPA 540/1-89/001.
U.S. EPA. 1990. Health Effects Assessment Summary Tables (HEASl). Third and Fourth
Quarters, F.Y. 1990. Office of Solid Waste and Emergency Response, Washington, D.C.
U.S. EPA. 1991a. Integrated Risk Information System (IRIS). Environmental Criteria and
Assessment Office, Cincinnati, OH.
U.S. EPA. 1991b. Supplemental Region IV Risk Assessment Guidance. U.S. EPA, Region IV,
Atlanta, GA.
Wellman, L. 1992. U.S. EPA Region IV. Personal Communication, January 28, 1992.
A:\PUBS\PAOJECTS\0845008\000.APG G-41 June, 1992
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I ATTACHMENT 11
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-liiiil --TABLE G-2-
DERIVATION Of HUMAN HEALTH RBTCLa FOfl PENTACHLOROPHENOL
FUTURE COMMERCIAL/INDUSTRIAL SITE USE
CLEAN-UP LEVELS EVALUATION
FORMER KOPPERS COMPANY, INC. SITE
BEAZER EA.ST, INC., MORAISl/lllE, NC
--lilil liiil --
Local Ot!-Slt• A• .. dent On-Si111 Worker
Cone. As.urning Eallmaled Alllk Cone. A.a.urning Eat!me,t.d RID\
Exlatlng Exla1lng E•l•t!ng No Oegrad.ilon A1-...mlng No No 0egradatlOfl A1wmlrw;i No ,.,. RME Mu. Occur., H Oegr-.:latlon, H ABT CL A■.umlrio No Degradation•· Clr;c;:ur■, •• Oagradatlon, u
Cone. Cone. Co!'IC, UNd In Fina! Calcutat.cl lri Final Oarl....cl tor Alak Laval: U.-d In Final C.lculaled In Final
Medium/ ArH {ppm) {ppm) (ppm) Risk A1N1sm.nt Risk "••aiament ,, ... •E-<» ,E.oe Risk A1N1sment Rl,ak AINHIT,enf
Surfaca Soll ,., .... NO NO ND ND NC NC NC NC NO NC
mo B 1.10E-01 1.elE-01 U!IJE-01 1.0lE-01 3.otlE-10 5E+04 5E+03 5E+02 1.lllE-01 !I.SoeE-00
m,C 3.ll!IE+02 ll.10E+02 3.22E♦03 11.10E♦02 11.1:zE-oe 1E+O<II 1E+03 1E+o2 e.1oe+o2 2.7llE-O!I
... ,... 0 NO ND NO ND NC NC NC NC NO NC
Sub1Ur1ae• Soll
A,-.a C 1.117E+01 l.70E+01 !l.eoE+02 ,.1oe+o1 3.a3E-O& 1E+OS 1E+04 1E+03 •.70E+01 !I.A7E-08
Sur1aca W•t••
Fire Pond 1.00E-OI 1.2'1E-OI 1.117E-OI 1.2GE-04 2.31E-OO IIE+OO IIE-01 IIE-02 NE NE
Ma-dlln Pond II.OOE-05 O.OOE-05 , . .-!IE-04 G.OOE-O!I 1.112E-OO ee+oo IIE-01 ee-02 NE NE
WHtam Ollch 7.e0E-OI 1.70E-03 A.ll!IE-03 1.70E-03 2.IIDE-0& eE+OO ee-01 IIE-02 NE NE
Sedlmant
Fl,-. Pood A.71E-01 1.13E+OO 5.04E♦OO 1.13E+OO 7.115E·10 1E+os 1E+04 1E+03 NE NE
Medlln Pond NO NO NO ND NC NC NC NC NE NE
Fir• Pond OS .-.e3E-01 t.OOE+OO 1.5-<IE+OO 1.00E+OO 1.47E-O& 7E+03 7E+02 7E+01 NE NE
Ground Wa!ar
Otlslt• !I.OOE-05 e.OOE-05 2.JOE-04 II.OOE-05 U7E-07 ,e-02 4E-03 <E-<M NE NE
""' Fire Pond ND NO ND ND NC NC NC NC NE NE
Ma-dlln Pond NO ND NO NO NC NC NC NC NE NE
NotH:
-
RBTCl Anumlng No ~rad•llon• •
Dart-=! for Risk U-wl: ,, ... ,e.o, ,e.oe
NC NC NC
3E+03 3E+02 3E+01 ... ,. 11!+02 SE♦01
NC NC NC
OE+0-4 OE+03 OE+02
NC NC NC
NC NC NC
NC NC NC
NC NC NC
NC NC NC
NC NC NC
NC NC NC
NC NC NC
NC NC NC
• -In lh• drat! r1ail HN..,..,.F'II•, d99radado" r•W• _,.. applied b eur1-eoll, eubeurfaee eoll, •nd .-dirr.nt. In ltw final rt• •-~l, how.,,..., 11 w-■ •numed Iha!"° d9',ll'Mladorl wlll oca.,r In any ,na,dlum.
II -Soure•: KER, 1G02.
$. Th• MCL !Qr 2,3,7,8--TCOD I•• propo.-d MCL.
ARAR ---'?plleab!. and Aal•v•nt OI' Appropr1•t• AequlNmant.
Met.. Mulmum Co"tamln•nt t.. ....
NC-Not C•leul•la-d.
NO -Not 0•1.e1ad.
NE. No Exposure I• - ■eurn,a,d tor thl11'9C•pl0f.
ABTCL. Alall-Ba.-d T•~•t CIHn-up l•wl.
AME • A-■acmabl• M•xlmum Expo11t.1re.
-• Oa.1 no! 1pplv.
TABG2A.W01 AN:2 111-Jun-92
-lllil
Soll h,v•t ._.,.,
"'"" "°"" ,-,...i
Pm,oe,lon C.rollna AAA/I
ofOrouM ARAI\ (MCl)
w ... , {ppm)• (ppm) (ppm)S
.. --
.. --
---
---
--0.001
---
- - -
llilll iilill liiliill liill
TABLE G-Ja
OfRIVATION Or HUMAN HF:ALTH RRTCl.• FOO PCODl"COF:
FUTURE COMMEACl.l.LANDUSTAIAL SITE USE
CLEAN-UP LEVELS EVALUATION
FORMER KOPPERS COMPANY, INC. SITE
BEAZER E"ST INC MORRISVILLE NC "
Existing Exl1ting
A,g. RME
Cone. Cone.
M-.:llum / ArH (ppm) {ppm)
Surlaca SoU
ArHA NA NA
Ar-■ B 7.00E--05 1.30E-O•
ArHC 5.50E-02 2.00E-01
ArHO N, NA
Subsurlace Soll
Area C IUOE-04 1.50E-OJ
Surlec. W.i•r
Fire Pond 1.85€-07 2.NE-07
M..:llln Pond 1.22E-08 1.QPE-08
WHtsm Oltch NC 4.20E-OI!
fledlmenl
Fire Pond 2.10€-04 4.~E-0-4
M..:llln Pond 7.80E-04 t.01E-03
Fire Pond OS e.50E-04 1.oeE-03
Ground Ws!er
Offslte e.e1e-11 t.SOE-10
Floh
Fire Pond 1.81E-05 3.85E-O!I
Mt>dtln Pond 1.111E-OS 2.e11e-oe
Editing
Mu.
Cone.
(ppm)
NA
1.30£-04
2.70E-01
NA
4.00E-03
2.85E-07
1.QPE-08
4.20E-08
4.00E-0-4
1.01E-OJ
1.oeE-OJ
1.50€-10
3.85E-05
2.e11e-0e
loc•I OIi-Sit• R•aid•nl
Cone:. A■-umlng E,tlmett>d Rlllk
No Degr..:latlon A■a,mlng No
Occur■,•• Degradation, ••
U•d In Fln•I Calculated In Final
Rip; A■N■-nl@ Al9k A1•1.,,..n1
NA NC
1.30E-04 1.21E-07
2.ooE-01 7.72E-0-4
NA NC
1.50€-03 e.~E-07
2.20E-07 e.83E-Oe
1.liltE-Oa 5.75E-07
4.20E-08 1.15E-OI!
4.50E-0-4 1.!11E-07
t.OtE-03 3.42E-07
1.C>eE-03 7.10E-OO
1.50E·10 4.02E-07
3.85E-05 1.113€-05
2.tlllE-Oe 1.35€,-0(1
iiiil --- -- --
On-Site Work•r Soll Targ.t
Cone. A,.,.mlng E■tlmet.d AIU: Lowl
No Oegr.datlon A-.iml~ No """"' RBTCl Auumlng No Oegradat1or,•. ~ur1,a1 Oe,gradatiofl, H ABTCl Aaaamlng No Degradation• -Pro*tlon
O•rl~ !or Rl■k La.,.1: U.-d ln Fhial Ca!c:ulated 111 Final O■rlwd k>I' Rl■k La ... l: of Grouod ,...,. ..... """' Risk A, .... menl@ Al1k A .. , .. .,.,.nl •E-<>< ..... """' Wa'9r (ppm)•
NC NC NC NA NC NC NC NC 0.007
,e-01 1E-02 1E-03 1.30E-0-4 2. H~E-0& OE-03 .,..,. """' 3E-02 3E-OJ 3E-O< 2.00E-01 J.•IIE-03 OE-03 .. ..,. .....
NC NC NC NA NC NC NC NC
2E-01 2E-02 2E-03 1.50€-03 8.~E-07 2E-01 2E-02 2£-03 0.007
"""' JE-07 3'-08 NE NE NC NC NC -
"""' 3E-07 3'-08 NE NE NC NC NC
"""' 4E-07 ..... NE NE NC NC NC
JE-01 3E-02 lE-03 NE NC NC NC -
JE-01 3E-02 3'-03 NE NE NC NC NC
,e-02 tE-03 , . ..,. NE NC NC NC
3'-08 ,,.., JE-10 NE NE NC NC NC -
2E-<M ,. ... "'""' NE NE NC NC NC -
2E-<>< ,. ... ,..,,. NE NE NC NC NC
Notes:
• -In the drsh ris.k ..... .,.,.nts, d'ijrsdatlan ratH -re applied 10 turfaee 9011, 9Ub11Urf•oa 11011, and .dlmerit. tn the llnal riM HNnma-nt. ho--, It was a-11'1-..:1 that no d99radallan wiU occur iri ariy 1'1-.dlum.
@ • Minor dl-::reparicl•• lri dlllJ>l•Y al concentratlori• belw"" the Ctean•Up UYels Evsluellon and the BeNllne RIM AsN..,_nt ""-Y occur due 10 roundln,g.
'1 -Source: KER, 1lilt2.
S. The MCL for 2,3,7 ,8-TCOO ls • propa.d MCL.
ARAR • Applleebl• and Relevsnl or Appropriai. Requlrenwnt. ARARs lor PCDOIPCOF sre Geriv.d k>f 2,3,7,8-TCOO.
MCL. Maximum Coriiamlnanl Uvsl.
NA. Nat Analyzt>d.
NC. Not Calculalt>d.
NE -No Exposure 1• aHu~ for thl• receptor.
RBTCL • Rl,k-Ba.d Targst C!ean,vp LeYel.
AME. Reaaanable Msxlmum f:,:pa11Ure.
- • Do., not apply.
TABG3A.WC1 RN. 2
lilil
N-F.-.,
Carollna AfWI
"""" (MCU
(ppm) (ppm)S
--
--
1.3E-11 -
--
2E-10 , ....
--
-lliil iiiil
TABLE 0-Aa
DERIVATION OF HUMAN HEALTH ABTCLs FDA PENTACHLOROPHENOL:
FUTIJRE RESIDENTIAL SITE USE
CLEAN-UP LEVELS EVALUATION
FOAMER KOPPERS COMPANY, INC. SITE
BEAZER EAST, INC., MORRISVILLE, NC
Existing falstlng
Avg. RME
Cone. Cone.
Medium / Area (ppm) (ppm)
Surface Soil ,., ... NO ND
Nea B 1.16E-01 1.63E-01
,., .. c 3.8SE+02 e.10E+02
,., .. 0 ND ND
Subaurfe.ce Soil ., ... ND ND
. Area B ND NO
Nea C 1.97E+01 4.70E+01
,., .. 0 ND ND
Surface Wa.ter
Fire Pond 1.00E-04 1.29E-04
Western Ditch 7.60E-04 1.70E-03
Sediment
Flr• Pood 4.71E-01 1.13E+oo
Western Ditch 1.06E-01 1.ese-01
Ground Water
Former Lagoon 1.63E-01 3.49E-01
Eastern Alee 3.SOE-03 1.01 E-02
W•111t"'"'1ArM 3.00F.-0~ 6.00E-05
Fish
Fire Pond NO ND
Notes:
Hypothetical On-Site Resident
Cr.,o. A .. umlng C1Um11t1K1 nl•k
Existing No Degradation Assuming No
Ma><. Occul'9, as Degradation, as
Cone. U11ed In Final Calculated In Final
(ppm) Risk Assessment Risk Assessment
NO ND NC
1.63E-01 1.BJE-01 e.74E-08
3.22E+03 8.tOE+02 3.35E41
NO NO NC
NO ND NC
NO NO NC
5.60E+02 4.70E+01 2.52E-07
NO NO NC
1.67E-04 1.29E-04 5.22E-08
4.86E-03 1.70E-03 2.69E-08
&.04E+OO 1.13E+OO 1.7"E-08
2.29E-01 1.ese-01 2.22E-OQ
1.49E+OO 3.49E-01 6.60E-04
4.65E-02 1.01 E-02 2.49E-05
1.ME-04 6.00E-05 1,48E-07
NO ND NC
liiil iilil ---
Soil Target
Love!
!or lhe N0'1h Fod.,.,
RBTCL Assuming No Degtt1.dation• • Protection Garoiina ARAR
Derived !or Risk Level: of Ground ARAR (MCL)
1E-04 1E-05 1E-06 Water (ppm) If (ppm) (ppm)S
NC NC NC 05 --
2E+02 2E+01 2E+OO
2E+02 2E+01 2E+OO
NC NC NC
NC NC NC 05 --
NC NC NC
2E+04 2E+03 2E+02
NC NC NC
2E-01 2E-02 2E-03 ---
6E+OO 6E-01 6E-02
eE+03 ee+o2 ee+o1 ---
7E+03 7E+02 7E+01
4E-02 <E-03 ,e-04 --0.001
4E-02 <E-03 <E-04
4E-02 4E-03 •E-<><
NC NC NC ---
••In the drart risk assessments, degmdation mies were applied to sur1aca soil, subsurface soil, and sediment In the final risk assessment, however, It was assumed that no degradation will occur in any medium.
II • Source: KER, 1992.
$·The MCL for 2,3,7,6-TCDD is a proposed MCL.
ARAR • Applicable and Relevant or Appropriate Requirement.
MCL. Maximum Contaminant Level.
NC -Not calculated.
ND • Not Oat.clad.
RBTCL • Risk-Based Target Clean-up Level.
RME • Ret11onabla Maximum E)(posur•.
- -Does not 1mply,
TABG4A.WQ1 AN: 2 18-Jun-92
-
liill liiil .. liiiil iiiil liiil .. -lilll .. TABLE G-Sa
Ut:fllVATION 01" HUMAN Hl::Allll IIOICLe run PCUU/l'GOr::
FUTURE RESIDENTIAL SITE USE
CLEAN-UP LEVELS EVALUATION
FOAMER KOPPERS COMPANY, INC. SITE
BEAZER EAST, INC., MORRISVILLE, NC
Existing Existing
Avg. RME
Cone. Cone.
Medium / Are,a (ppm) (ppm)
Surfe.ce Soil
Area A NA NA ,.,_B 7.00E-05 1.30E-04 ,.,_c 5.SOE--02 2.00E-01
,.,_ 0 NA NA
Subsurface SOI
,.,_A NA NA
Area 8 NC 2.00E--05
AreaC 6.00E-04 1.SOE-03
Arria. D NA NA
Surlac• We.ter
Fire Pond 1.65E-07 2.29E-07
Western Ditch NC -4.20E-08
Sediment
Fire Pond 2.10E-04 -4.SOE-04
Western Ditch NC 1.70E-04
Ground We.tar
Former Ltagoon 1 .96E--08 e.20E-08
Ee.stern Area 5.861E-08 1.69E-07
Western Aree. NA NA
Fish
Rre Pond 1 .81 E-05 3.85E-05
Notes:
Existing
Max.
Cone.
(ppm)
NA
t .30E-04
2.roe-01
NA
NA
2.00E-05
-4.00E-03
NA
2.SSE-07
-4.20E-08
-4.00E-04
1.70E-04
7.93E-08
1 .f59E-07
NA
3.85E-05
Hvcothetical On-Site Resident
Cone. Assuming Eetlmat-.d Alsk
No Degradation Ast1:uming No
Occurs, o.s Degrade.tion, as
Used In Final Catculeited in Final
Risk Assessment@ Risk Asse!:sment
NA NC
1.30E-04 2.66E-05
2.00E-01 4.23E-02
NA NC
NA NC
2.00E-05 -4.26E-08
1.SOE-03 -4.12E--Oe
NA NC
2.29E-07 1.SOE-04
-4.20E-08 1.1SE-06
4.SOE-04 3.54E-06
1.70E-04 1.11E-06
e.20E--08 1.91 E-04
1.89E-07 5.19E-04
NA NC
3.85E-05 8.16E-OS
- --.. .. -
Soil Target ,-..
fO( the North fode,aJ
RBTCL Assuming No Degradation• -Protection Carolina ARAR
Derived IOf Risk Level: of Ground ARAR (MCL)
1E-04 1E-05 lE-06 Water (ppm) fl (ppm) (ppm)$
NC NC NC 0.007 - -
SE-O<I SE-05 SE-06
SE-O<I SE-05 SE-06
NC NC NC
NC NC NC 0.007 - -
SE-02 SE-03 SE-O<I
-4E-02 AE-03 <E-O<I
NC NC NC
2E-07 2E-08 2E-09 -1.3E-11 -
AE-06 -4E-07 <E-08
,e-02 1E-03 1 E-O<I - - -
2E-02 2E-03 2E-O<I
3E-08 3E-09 3E-10 -2E-10 SE-08
3E-08 3E-09 3E-10
NC NC NC
SE-OS SE-06 SE-07 - - -
• -In the draft risk e.ssessments, degrade.tion rates were applied to surface soil, subsurface soil, and sediment. In the final risk assessment, however, it was as!lumed that no degradation will occur In any medium.
@. Minor discrepanci8!1 in display of concentrations between the Clean-Up Levels Evaluation and the Baseline Risk Assessment may occur due to rounding.
II -Sourc•: KER, 1992.
S • The MCL for 2,3,7,8-TCDD Is a propO!ed MCL
ARAR. Appllcnble 11nd R"'"v11nt or Appropril'l.te Requlrem..-,1. ARAR1 for PCDO/PCDF are dertv!Kt for 2,3,7,8-TCDO.
MCL • Maximum Conl.amlnant Level.
NA • Not Analyzed.
NC. Not Co.lculo.t8d.
ABTCL • Risk-Based Tl!lrget Clean-up Level.
AME -Ret1sonable Ma,::lmum Exposure.
- -Does not apply.
TABGSA.WQ1 RN:2 16-Jun-92
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I DRAFT
I ATTACHMENT 12
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.. liiiil
TABLE G-8 -REVISED
SUMMARY OF REMEDIAL GOALS
CLEAN-UP LEVELS EVALUATION
FORMER KOPPERS COMPANY, INC. SITE
BEAZER EAST, INC., MORRISVILLE, NC
Commerclal/lndustrlal Site Use
iiiil
Existing Maximum
Mod/um / Area Constituent Concentration (ppm)
Surface Soil / Area C Pentachlorophenol 3220
PCOD/PCDF 0.3
Pentachlorophenol 660
Subsurface Soil / Area C PCDD/PCDF 0.00,
Fish / Fire Pond PCDD/PCOF ,e-05
Residential Site Use
Surface Soil / Area C Pentachlorophenol 3220
PCDO/PCDF 0.3
Pentachlorophem~ 560
Subsurface Soil/ Area C PCOD/PCDF 0.004
Suda,;,; W<l\or / f'ire Pond PCDD/PCDF 3E·'J7
Fish / Fire Pond PCDD/PCDF 4E-05
Ground Water/ Pentachlorophenol 1.5
Former Lagoon Area PCDD/PCDF BE-OB
Ground Wa:er / Pen :a chi oroph enol 0.05
r:.,s!-•rn Ar':'a PCDD/?COF 2E-07
Notes:
ARAR -Applicable and Relevant or Appropriate Requirement.
MCL • Maximum Contaminant Level.
RBTCL -Risk-Based Target Clean-up Level.
liiil iiill
Human Health
RBTCL at tho 1 E-04
Risk Lovol (a) (ppm)
3000
0.006
9000
0.2
2E-O<I
200
5E-O<I
20000
0.04
2:::-01
SE-OS
0.04
3E-OB
0.04
3f.()8
(a) -Human Health ABTCLs were derived tor each risk level, assuming degradation does not occur.
Soil ABTCLs for Commercial/Industrial Site use are for on-Site workers.
(b) -ARARs for PCOO/PCOF are derived tor 2,3,7,6-TCDD.
(c) -The MCL fa 2,3,7,B-TCDD is a proposed MCL.
--Does not apply.·
SUMMAAYG.WQt A.N .. 8 18-Jun-92
liiil iiill --.. liiaiil
Human Health Human Health Soll Target Lovol North Carolina Fodoral ARAR Boazor East, Inc.
RBTCL at tho 1 E-05 RBTCL at tho 1 E-06 for tho ProtocUon of ARAR (MCL) Recommondecl
Risk Lovol ta) (ppml Risk Lovol (a) (ppm) Ground Water (ppm) b) (ppm) b)(c) (ppm) Clean-up Goal (ppm)
300 30 95 --95
6E-O<I 6E-05 0.007 0.007
900 90 95 95
0.02 0.002 0.007 --0.007
2E-05 2E-06 ---2E-05
20 2 95 ---95
5E-05 SE-06 0.007 --0.007
2000 200 95 95
0.004 ,tE.04 0.007 .. .. 0.007
2E·08 2::C·08 .. .. .. 2l:·OO
SE-06 SE-07 ------SE-06
0.004 <tE-04 .. --0.001 0.001
3E-09 3E-10 -2E-10 5E-08 SE-08
0.004 4E-04 .. 0.001 0.001
3E-09 3!:-10 .. 2E-10 SE-08 SE-08
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DRAFT
ATTACHMENT 13
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TABLE E-2
DEGRADATION FACTORS USED TO CALCULATE BASELINE RISKS
HUMAN HEALTH EVALUATION
FORMER KOPPERS INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
CONSTITUENT. ·. DEGRADATION.FACTOR(# ,YEARS) ·
Phenolics• 0.030 (8 years -Trespasser Evnluation)
0.013 (18 years -Local Resident Evaluation)
0.012 (20 years -On-Site Worker Evaluation)
0.008 (30 ye.ars -Hypothetical On-Site Resident Evaluation)
Total TCDD-TE" 0.80 (8 years -Trespasser Evaluation)
0.62 (18 years -Local Resident Evaluation)
0.59 (20 years -On-Site Worker Evaluation)
0.48 (30 years -Hypothetical On-Site Resident Evaluation)
Notes:
• -Degradation foctor for pentachlorophcnol.
•• -Degradation factor for 2,3,7,8-TCDD.
TABLE_E2.WKI
RN: 3
l8-Jun-92
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I TABLE E-3
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ANALYSIS OF DEGRADATION
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST, INC., MORRISVILLE, NC
Pentachlorophenol
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Medium -Arca:
Receptor
Surface Soil -Arca B:
Local Resident Trespasser
On-Site Worker
Construction Worker
Hyp. On-Site Resident
Surface Soil -Arca C:
Local Resident Trespasser
On-Site Worker
Construction Worker
Hyp. On-Site Resident
Subsurface Soil -Arca B:
Hyp. On-Site Resident
Subsurface Soil -Arca C:
Local Resident Trespasser
On-Site Worker
Construction Worker
Hyp. On-Site Resident
Sediment -Fire Pond DS:
Local Resident
Sediment -Fire Pond:
Local Resident Trespasser
Hyp. On-Site Resident
Sediment -Medlin Pond:
Local Resident Trespasser
Sediment -Western Ditch:
Hyp. On-Site Resident
Notes:
ND -Not Detected.
NC -Not Calculated
DEGRAD.WKI
Degraded
Cone.
(mg/kg)
0.0049
0.002
0.163
0.0013
24.39
9.8
809.7
6.5
ND
1.42
0.567
47.04
0.378
0.0329
0.034
0.009
ND
0.00133
R.N.:4
Nondegradcd
Degraded Cone.
IUsk (mg/kg)
9.27E-l2 0. 163
6.70E-I I 0.163
!.07E-IO 0.163
5.42E-IO 0.163
l.84E-07 809.7
3.33E-07 809.7
5.32E-07 809.7
2.69E-06 809.7
NC ND
I.ISE--09 47.04
6.59E-IO 47.04
4.84E-08 47.04
2.03E--09 47.04
!.96E-l0 1.09
2.30E-I I I. I 3
!.44E-IO 1.13
NC ND
!.78E-II 0.165
l8-Jun-92
Dioxin
Dcgrndcd N ondegraded
Nondcgradcd Cone. Degraded Cone. Nondcgnided
Risk (mg/kg) Risk (mg/kg) Risk
3.0SE-IO I .03E-04 9.72E-08 l.30E-Q4 !.23E-07
5.46E-09 7.60E-05 l.30E-06 !.30E-Q4 2.22E-06
!.07E-10 1.JOE-04 4.23E-08 l.30E-Q4 4.23E-08
6.SOE-08 6. !OE-05 1.26E-05 l.30E-Q4 2.69E-05
6.IIE-06 0. 16 6. !8E-Q4 0.204 7.88E-Q4
2.75E-05 0.1 2.07E-03 0.204 4.22E-03
5.J2E-07 0.204 6.73E-05 0.204 6.73E-05
3.35E-04 0.097 2.0!E-02 0.204 4.23E-02
NC 7.55E-06 2.02E-08 !.59E-05 4.25E-08
3.SIE-08 I .23E-03 5.00E-07 !.54E-03 6.26E-07
5.47E-08 9. l lE-04 5.30E-07 !.54E-03 8.96E-07
4.84E-08 1.54E-03 7.91E-07 !.54E-03 7.9IE-07
2.53E-07 7.30E-04 1.96E-06 !.54E-03 4.l3E-06
6.49E-09 8.48E-04 4.42E-06 l.06E-03 5.53E-06
7.64E-IO 3.58E-04 I .2IE-07 4.SOE-04 l.52E-07
I .SOE-08 2.12E-04 I .68E-06 4.SOE-04 3.57E-06
NC 8.09E-04 2.74E-07 I.OIE-03 3.42E-07
2.2IE-09 7.89E-05 5.29E-07 !.70E-Q4 l.48E-06
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TABLE G-1
LITERATURE REVIEW OF PENTACHLOROPHENOL DEGRADATION RATES
CLEAN-UP LEVELS EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
CONSTITUENT Medium Half-Life
PHENOL Aerobic Soil 23 -178 days
PHENOL Anaerobic Aqueous 42 days -4.2 years
PHENOL Soil 1 day
PHENOL Soil 2.2 days
2-CHLOROPHENOL Soil Suspension 14 days•
2-CHLOROPHENOL Soil >64 days•
2-NITROPHENOL Soil >64 deys•
2-NITROPHENOL Soil 81% in 7 days
2-NlTROPHENOL Soil 84.5% in 14 days
2-NITROPHENOL Soil 93.5% in 21 days
2-NITROPHENOL Soil 98.5% in 28 days
2-NITROPHENOL Soil 7 -28 days
2-NlTROPHENOL Anaerobic Aqueous 7 -28 days
4-NITROPHENOL Soil 16 days•
4-NITROPHENOL Soil 17 -29 hours
4-NITROPHENOL Anaerobic Aqueous 6.8 -9.8 days
2,3-DlCHLOROPHENOL Anaerobic Sediment 19 days
2,3-DICHLOROPHENOL Anaerobic Sediment 22 days
2,3-DICHLOROPHENOL Anaerobic Sediment 30 days
2,3-DlCHLOROPHENOL Anaerobic Sediment 24 days
2,3-DICHLOROPHENOL Anaerobic Sediment 52 days
2,3-DICHLOROPHENOL Anaerobic Sediment 16 days
2,6-DICHLOROPHENOL Anaerobic Sediment 31 days
2,3-DlCHLOROPHENOL Anaerobic Sediment 33 days
2,3-DICHLOROPHENOL Anaerobic Sediment 35 days
2,3-DlCHLOROPHENOL Anaerobic Sediment 43 days
2,3-DlCHLOROPHENOL Anaerobic Sediment 20 days
2.4-DlCHLOROPHENOL Soil Suspension 9 days•
2.4-DlCHLOROPHENOL Soil 8% in 7 days
2,4-DlCHLOROPHENOL Soil 47% in 14 days
2,4-DICHLOROPHENOL Soil 91.5% in 21 days
2,4-DICHLOROP!IENOL Soil 98.5% in 28 days
2,4-DICHLOROPHENOL Soil 7.3 days
2.4-DICHLOROPHENOL Soil 70 days
2.4-DICHLOROPHENOL Anaerobic Aque.ous 13.5 -43 days
2,4-DIMETHYLPHENOL Soil 1-7days
2.4-DIMETHYLPHENOL Soil 1 - 2 days
2.4-DIMETHYLPHENOL Anaerobic Aqueous 4 -28 days
2,4-DlNITROPHENOL Soil 28 days
2,4-DINITROPHENOL Soil 3 - 7 d,ys
2,4,6-TRJCHLOROPHENOL Soil Suspension 5 days•
2,4.6-TRlCHLOROPHENOL Soil 7 -70 days
2,4,6-TRlCHLOROPH ENOL Anaerobic Aqueous 169 days -5 years
2,4,6-TRlCHLOROPHENOL Anaerobic Sediment 21 days
2-METHYL-4.6-DINITROPHENOL Soil 7-21 doys
Reference
(a)
(b)
(c)
(c)
(d)
(e)
(e)
(f)
(f)
(f)
(f)
(g)
(h)
(e)
(i)
(h)
(j)
(j)
(j)
(j)
(j)
(j)
(j)
(j)
(j)
(j)
(j)
(d)
(f)
(f)
(f)
(f)
(k)
0)
(m)
(n)
(c)
(n)
(h)
(h)
(d)
0)
(k)
(j)
(o)
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TABLE G-1
LITERATURE REVIEW OF PENTACHLOROPHENOL DEGRADATION RATES
CLEAN-UP LEVELS EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
CONSTITUENT Medium Half-Life
2-METHYL-4,6-DINITROPHENOL Anaerobic Aqueous 2.8 -7.1 days
2,3,4,6-TETRACHLOROPHENOL Soil Suspension >72 day,•
2,3,5,6-TETRACHLOROPHENOL Anaerobic Sediment 19 days
PENTACHLOROPHENOL Soil Suspension >72 days•
PENTACHLOROPHENOL Soil 28 days
PENTACHLOROPHENOL Soil 23 -178 days
PENTACHLOROPHENOL Soil 25% in 12 days
PENTACHLOROPHENOL Soil 6 days
PENTACHLOROPHENOL Soil 80% in 160 days
PENTACHLOROPHENOL Anaerobic Soil 7% in I 60 days
PENTACHLOROPHENOL Soil 12 -14 days
PENTACHLOROPHENOL Soil 90%, 24 -100 hours••
PENTACHLOROPHENOL Soil 24 % in 30 days
PENTACHLOROPHENOL Soil 21 hours
PENTACHLOROPHENOL Anaerobic Aqueous 42 days
PENTACHLOROPHENOL Anaerobic Aqueous 4.2 years
Notes:
• -Days to complete decomposition.
++ -Sample was inoculated.
Sources:
(a) Delaune et al., 1983. (k) Bal<er et al., 1980a.
(b) Ide et al., 1972. 0) Haider et al., 1974.
(c) Medvedcv et al., 1972. (m) Aly et al., 1964.
(d) Woodcock, 1971. (n) Howard et al., 1991.
(e) Ale,andcr, 1966. (o) Kincannon et al., 1985.
(I) Bunch et al., 1967. (p) Murthy et al., 1979.
(g) Sasaki, 1978. (q) Edgehill et al., 1983.
(h) Sudhakar-Barik et al., 1978. (r) Bal<er et al., 1980b.
(i) Loekke, 1985. (s) Bal<er et al., 1980c.
(j) Peijnenburg et al., I 992. (t) McGinnis, I 985.
PENTALIT.WKI RN: 5 18-Jun-92
Reference
(h)
(d)
(i)
(d)
(p)
(n)
(q)
(q)
(r)
(r)
(q)
(q)
(s)
(t)
(b)
(k)
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• n
DRAFT
ATTACHMENT 14
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TABLE 2-12
CONSTITUENT CONCENTRATIONS IN OFF-SITE SAMPLES
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
GROUND WATER -OFFSITE (a)
Range of
Sample
Quantitation
Limits (ug/l) $
Minimum
(ug/l)
Maximum
(ug/l)
Arithmetic
Mean
(ug/l)
Upper 95th
CI on
Arith. Mean Frequency of
(ug/1) Detection #
CONSTITUENT: =========== ======== == ====== == ======== ========= ======-==
PHENOL
2-CHLOROPHENOL
:f.:fifrROPHENoi.. > 2:,{LoiMEriiYtP1-1iiNOLH•··
.2,4fDlCHLO!lO~HENOL i
4-CHLORO-3-METHYLPHENOL
2,4,6-TRICHLOROPHENOL
2,4-DlNITROPHENOL
,FfifrRoriiliiio1./· :Uii.s!tilrEnAcilroii.Or1-1iiNOi./ •·2ii:igf1-1yi)--1:ci:!01r-irfRof11gij9i:•·.
PENTACHLOROPHENOL
ISOPROPYL ETHER
Notes:
0.25-3.85
0.25-278
0.25-55.5
0.5-6.25
0.5
0.25 •
0.25 •
ND
0.5 •
0.5 •
32.4 I
278 •
ND
13.5
5.37
2.48
13.14
NC
1.48
0.71
5.47
38.12
NC
2.73
1.07
(a) -Data from the Off-site monitoring wells thought to be most influenced by constituents from the Site were included in
the Baseline Risk Assessment, and are listed in Table 2-1.
$ -Reported values are equal to one-half the sample quantitation limit.
• -Value is below detection limit: reported value is equal to one-half the sample quantitation limit.
# -Frequency of Detection= Number Detected : Number Analyzed.
J -Estimated value be1ow reporting limit.
NR -Not Reported; this constituent was detected in all samples in this medium/area.
OFFSITEI.WKI
RN: 8
17-Jun-92
4:23
3:23
0:23
1:23
3:28
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DRAFT
ATTACHMENT 15
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APPENDIX C-3
SKIN PERMEABILITY CONSTANTS
The skin permeability constants used for the constituents of potential interest in this human
health evaluation were prescribed by the U.S. EPA Region IV (K.P. Koporec, personal
communication, April 23, 1991} and are shown on Table C-3.1. These coefficients apply only
to aqueous media and are used in the swimming exposure pathway. They are taken from
the Interim Guidance for Dermal Exposure Assessment prepared by EPA's Exposure
Assessment Group of the Office of Health and Environmental Assessment (Interim Final,
March 1991). This document has not yet undergone EPA's peer review process, and it is
marked 'DO NOT CITE OR QUOTE." In January 1992 a new version of the Guidance for
Dermal Exposure Assessment was published. The permeability coefficients for the
constituents of interest at this site that are recommended in the 1992 version of the Guidance
for Dermal Exposure Assessment are the same as in the interim (1991) version of that
document, except for 2-nitrophenol and 2,4-dimethylphenol. The permeability coefficients for
2-nitrophenol and 2,4-dimethylphenol that are used in the revised Baseline Risk Assessment
are taken from the 1991 draft of the Guidance for Dermal Exposure Assessment, and are
more conservative than those recommended in the 1992 guidance for Dermal Exposure
Assessment. Tl=io pFOsoribed values are provided iR Table C a.1. eNSR l=ias used tl=io per
FReability ooollioioRIS FOqUiFOd by ePA RegioR IV iR tl=io AUFRaR l=iealtl=i o•,•aluatiOR but l=ias
rosorvatiORS about several of IR0FR.
At this time, experimentally determined permeability coefficients exist for only a limited
number of constituents. A recent summary of coefficients, including those experimentally
derived, l=las appeared in the Interim Guidance. The following is a brief review of some of
these values., but e~lSR l=ias disooveFOd tl=irougl=i a pFOliFRiRary review tl=iat tl=ie GuidaRoo
reports eFFOReous perFReabilily ooellioieRIS for SOFR0 GORSlitueRts.
Permeability coefficients are available in the EPA report (1991) for most of the Site-related
constituents. Nine were derived experimentally. The most reliable of these, for phenol, 2-
chlorophenol, 2,4-dichlorophenol, 4-chloro-3-methylphenol, 2,4,6-trichlorophenol and 4-
nitrophenol, were derived in experiments by Roberts et al. (1977) involving human subjects.
They are recommended by EPA as default values for those constituents. Permeability coef-
ficients for 2-nitrophenol, 2,4-dimethylphenol and 2,4-dinitrophenol were derived in a study by
Huq et al. (1986) on phenol absorption through hairless mouse skin. This animal model is
not very useful for predicting the permeability of constituents through human skin, because
hairless mouse skin is known to be much more permeable to constituents than human skin.
A:\PUBS\PROJECTS\0845008\000.APC C-29
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Although EPA also reeemmeAds usiAg these values, they These values (particularly 2-I
nitrophenol and 2,4-dimethylphenol) are not consistent with values derived for other phenolic
constituents and ENSR believes that they should not be used. The published dermal
permeability value for 3-nitrophenol and 4-nitrophenol (which are closely related to 2-
nitrophenol) is 5.6 x 1 a-a, two orders of magnitude lower than the value 1.01 x 10-1
recommended by EPA for 2-nitrophenol. The Huq et al. report (1986) is currently under
review by ENSR. Therefore, the permeability coefficients derived in these experiments
(including that for 2,4-dinitrophenol) are in question.
Revised permeability coefficients for 2-nitrophenol and 2,4-dimethylphenol were published in
the January 1992 Guidance for Dermal Exposure Assessment (5E-03 and 1.5E-02,
respectively). Because the revised permeability coefficients are currently under review by
ENSR, the revised Baseline Risk Assessment contains estimates of potential exposures using
the PC values that were initially requested by the EPA.
The remainder of the values provided by EPA Region IV were not included in the list of
recommended coefficients in the Interim Report. Three permeability coefficients were
calculated using an equation based on the relationship of log K.,,, and molecular weight to the
log permeability coefficient (Kasting et al., 1987). This equation is currently being reviewed
by ENSR, and one potential error has been found. The coefficient for pentachlorophenol is
calculated based on the Kasting equation using a log K.,w of 5.86. The log K.,w for pen-
tachlorophenol has been reported in other sources to be much lower (5.01 -Verschueren,
1983). This error will result in an overestimate of the value of the permeability coefficient.
Other coefficients calculated for pentachlorophenol with different equations that appear in the
Interim Report are as low as 2.77 x 10'4• The permeability coefficients for 2-methyl-4,6,
dinitrophenol and TCDD were also calculated using the Kasting et al. equation and are being
reviewed.
Default values of 1.§ ic 10·3 were used for The EPA Region N's recommended default PC Value
for water (1.5E-03) was used for 2,3,5,6-tetrachlorophenol and isopropyl ether. This value
(1.ee 03) is the permeability ooellioieAI published in the .'Rterim Guieanoe for Dermal
&ff)esure Assessment (1991) fer two steroids, pregAeAoloAe aAd progesteroAe, whioh have
moleoular weights of over 300. II is ROI elear why this value is used as a default for the two
ooAslilueAIS, as they are vastly dillereAI (2,3,e G telraohloropheAol has a moleoular weight of
182 aAd isopropyl ether has a moleoular weight of 102). Values oaloulated usiAg aA equatioA
suoh as KasliAg et al. 's that tal<es into aooouAI the eonslitueAI speoifio ootanol water partilioA
ooellioieAls and moleoular weights would be preferable.
R:\PUBS\PROJECTS\0845008\000.APC C-30
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DRAFT
ATTACHMENT 16
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TABLE 4-6
DERIVATION OF AGE-SPECIFIC RESPIRATION RATES
HUMAN HEALTH EVALUATION
FORMER KOPPERS COMPANY INC. SITE
BEAZER EAST INC., MORRISVILLE, NC
AVG. HOURS • •AVG.% OF DAY
SPENT @EACH. SPENT @EACH
ACTIVITY LEVEL(~) \ACTIVITY LEVEL
YOUNG CHILD:
Low 22.40 93.25%
Med. 1.40 5.83%
High 0.22 0.92%
Total 24.02 100.00%
OLDER CHILD:
Low 22.40 93.25%
Med. 1.40 5.83%
High 0.22 0.92%
Total 24.02 100.00%
ADULT:
Low 22.40 93.25%
~led. 1.40 5.83%
High 0.22 0.92%
Total 24.02 100.00%
Source:
(•) Anderson et .i., 1985.
(b) U.S. EPA, 1989b.
T ABLE4-6. WK I
RN: 3
I0-lun-92
INHALATION RATE i~itf+;bi~l+~ c.;,•:inif\ /hi> · cm·'i,;;~rl
0.60
2.00
2.40
0.70
3.20
4.20
0.58
2.05
3.85
13.440
2.800
0.528
16.768
15.680
4.480
0.924
21.084
12.992
2.870
0.847
16.709
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ATTACHMENT 17
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and bioavailability of constituents for the relevant routes of exposure and matrices has been
reviewed. Based on these data, AAFs for each relevant compound/route/medium situation have
been derived and are shown in Table 4-2. The scientific basis for the derivation of these AAFs
is presented in Appendix C-1.
4.3.2 Inhalation Factors
Particle deposition and retention in the human lung is highly dependent on the size of the inhaled particle. It is not possible to know the size distribution of the Site-derived particles at all possible
receptor locations. To be protective of human health, it is conservatively assumed that all of the
particles at all locations are particles with diameters of 3 to 4 µm. Particles 3 to 4 µm in size
have the highest fractional deposition in the lung. Note the baseline risk assessment assumes
that the total concentration of particles in air is equal to the annual average PM10 concentration
from two monitoring locations, 0.0334 mg/m~ (Durham and Raleigh, 1987 Ambient Air Quality I Report) (State of North Carolina, 1989). The PM10 concentration includes particles of up to 10
µm in size. The particles between 5 and 10 µm in size will be taken up less efficiently than assumed by this baseline risk assessment, thus, the baseline risk assessment overestimates
potential exposures via inhalation of dust. ( A more realistic estimate of potential mcposure oould have been estimated by using assi;mplions more representative of aoti;al oonditions.)
Studies of PM,0 and Total Suspended Particulate values at construction sites contribute additional
evidence thatthe PM!!d of 0.0334 mg/m~ (State of North Carolina, 1989) is a conservative
estimate for all receptors. An analysis of three construction sites in Massachusetts demonstrates
a range of PM10 values between 0.017 for an 8-hour minimum (Lowell, MA) and 0.078 for a 24-
hour maximum-(Quincy, MA), and an annual average of 0.036 mg/m~ (Charlestown, MA) (ENSR,
1989b). The PM!!d used in this Baseline Risk Assessment (0.0334 mg/m~) represents an estimated particulate matter in air concentration that is within the range of reasonably expected
annual PM10 values for construction activities, according to these studies.
The PMill used in this Baseline Risk Assessment, therefore, likely overestimates the magnitude
of particulate matter in the ambient air for the off-site resident, hypothetical on-site resident, and
on-site worker receptors. This PM !Id value is also a reasonable assumption for the construction
worker receptor, as the value lies within the range of the annual PM ill for the construction sites
studied. Indeed, the construction worker receptor potentially inhales particles at the site for one year, so an annual PMl'J' when it is coupled with an inhalation rate of 20.8 m~/day, is likely to be a conservative estimate, even for the construction worker receptor. Thus, the use of a PM !Id that
is within the annual average range for a construction site is consistent with the definition of an
RME, since the average value for the construction worker is likely to overestimate the PMill for
normal activities, and reflect construction activities at the site.
R: \PUBS\ PROJECTS\ 084 5008\ 000 .S4 4-11 June, 1992
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•••
This baseline risk assessment assumes that the clearance to the gastrointestinal tract of particles
deposited in the lung is negligible and that 100% of the material deposited in the trachea and
bronchial tubes is cleared and subsequently swallowed. To determine the relative deposition and
clearance of inhaled particles compared to the experimental studies from which the EPA CSFs
and RfDs were derived, the exposure conditions for the relevant dose-response studies were
evaluated. The inhalation factors for each constituent evaluated at the Morrisville Site are listed
in Table 4-3. The detailed derivations of these factors are presented in Appendix C-2.
4.3.3 Skin Permeability Constants
Skin permeability constants are used to estimate the potential dose of a constituent absorbed
by skin in contact with water. This assessment used the dermal permeability constants for
potential absorption from aqueous media provided by EPA Region IV (K. Koporec, personal
communication, April 1991). The constituent-specific permeability constants are reported in
Table 4-4. The permeability constants used here are based on preliminary EPA guidance and
because this guidance has not been peer-reviewed, care should be taken when using these
values. A discussion of the appropriateness of these constants is provided in Appendix C-3.
4.4 Potential Exposure Scenarios at the Morrisville Site
Current and future exposure scenarios at the Morrisville Site are described below for the potential
receptors and PEPs identified above. The hypothetical exposure scenarios are based on a set
of assumptions that are summarized in Table 4-5. Table 4-5 presents all receptor-specific
exposure assumptions used in this assessment. The assumptions that are prescribed by EPA
are identified; all other assumptions represent the best professional judgement of the risk
assessors. The best professional judgement of the risk assessors is, however, influenced by
EPA-prescribed methods, and in many cases the values chosen for certain assumptions would
be lower if this baseline risk assessment were conducted outside of EPA domain. It is important
to remember that the objective of the EPA-prescribed RME assessment is to estimate the
reasonable maximum exposure for each pathway, and as a result, most intake variables need
not be at or near their reasonable maximum in order to be health-protective. The sum of all
assumptions is intended to represent a receptor's potential reasonable maximum exposure for
each pathway. However, when these pathways are summed to estimate total Site exposure for
a receptor, the sum of several 'reasonable maximum estimates" may result in a total exposure
which overestimates actual potential exposures.
As shown in Table 4-5, the Local Resident and Hypothetical On-Site Resident are separated into
three or four groups: (1) young child, (2) older child, (3) trespassing teenager (local resident
R:\PUBS\PROJECTS\0845008\000.S4 4-12 June, 1992
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DRAFT
ATTACHMENT 18
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Attachment 18
Insert for Appendix E-4:
As described in front section of Appendix E, in the first drafts of this report, phenolic compounds,
pentachlorophenol and PCDD/PCDF were assumed to naturally degrade in soils and sediment
over time. Based on data available in the literature, the degradation rate (half-life) for phenolic
compounds and pentachlorophenol in these media was assumed to be 60 days. The
degradation rate for PCDD/PCDF in these media was assumed to be 12 years. At the request
of U.S. EPA, Region IV, the degradation factors used to estimate potential exposure to
constituents in soils and sediment were removed from the final draft of the report. The tables
that follow contain the original exposure models used to estimate potential assumed risk (for
both assumed carcinogenic and assumed non-carcinogenic effects), and the scaling tables that
were used to remove the degradation factors and to estimate potential assumed risk from these
constituents assuming degradation does not occur.