NCD991278540_19981015_Weyerhaeuser Company_FRBCERCLA RISK_Response to Agency Comments on the Screening Ecological Risk Assessment-OCR

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October 15, 1998
Ms. Jennifer Wendel
Remedial Project Manager
USEP A Region IV
Waste Management Division
61 Forsyth Street, SW
Atlanta, Georgia 30303-3104
OCT 19 1998
SU PE RFU ND Sl:v i ,0"
Subject: Response to Agency Comments on the Screening Ecological.Risk Assessment
Weyerhaeuser Martin County Facility
State Road 1565, Martin County, North Carolina
Dear Jennifer:
Weyerhaeuser Company (Weyerhaeuser), and RMT, Inc. (RMT), have reviewed and prepared
responses to the United States Environmental Protection Agency (USEPA) review comments
dated September 16, 1998, on the Screening Ecological Risk Assessment prepared for the
referenced facility.
The responses to USEP A review comments are presented in Attachment 1 to this letter. For
ease of review the original comment is presented in bold typeface with the accompanying
response following in normal typeface. Attachment 2 includes supplements to existing
appendices, a revised replacement Section 4, and selected replacement pages, tables and
figures, prepared in response to specific review comments.
As outlined in your correspondence dated September 16, 1998, resolution of review comments
will be incorporated into subsequent steps of the ecological risk evaluations planned for the
source areas at the facility. Based on the screening ecological risk assessment completed for the
Welch Creek source area, USEPA concluded that a Baseline Ecological Risk Assessment was
necessary. As such, an Ecological Risk Assessment Study Design and Sampling and Analysis
Plan for the Welch Creek source area is under development. The screening ecological risk
assessment for Landfill No.l will be documented in an addendum after receipt of validated
data from the initial phases of the Remedial Investigation (RI) characterizations of that source
area.
Consistent with Step 5 of the Ecological Risk Assessment Process (USEP A, 1997), field
verification activities will be conducted to ensure that elements of the proposed/approved
work plans are implementable. Results of this field verification will be presented to USEPA in
a technical memorandum compiled by December 15, 1998. The technical memorandum will
RMT, Inc.
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RMT, INC.
100 V"DAE BLVD. -29607-3B25
P.O. Box 1677B -29606-677B
GREENVILLE, SC
B64/2B1-0030 -B64/2Bl-02BB FAX
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Ms. Jennifer Wendel
USEP A Region IV
October 15, 1998
Page 2
describe suggested modifications, if any, to the Ecological Risk Assessment Study Design and
Field Sampling and Analysis Plan.
Please call if you have any questions regarding the enclosed submittals.
Sincerely,
RMT, In
~d~ aren C. Saucier, Ph.D.
onsulting Environmental Scientist
~~ ~~Jxt1
Kathryn R. Huibregtse
Principal-In-Charge
Attachment 1 Response to USEPA Comments on the Screening Ecological Risk Assessment
Attachment 2: Revised replacement text, tables and figures
XC:
RMT, /11c.
Rodney Proctor, Weyerhaeuser Company
Joe Jackowski, Weyerhaeuser Company
Project File 5100.12
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RMT. lnc.
Attachment 1
Response to USEPA Comments on the
Screening Ecological Risk Assessment
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2.
ATTACHMENT 1
RESPONSE TO USEP A COMMENTS ON THE
SCREENING ECOLOGICAL RISK ASSESSMENT
WEYERHAEUSER MARTIN COUNTY FACILITY
Page 2-2 and Appendix A. Please amend these Sections to reflect that the shortnose
sturgeon (Acipenser brevirostrum), a federally listed endangered species, has recently
been documented to occur in the vicinity (Bachelor Bay of Western Albemarle
Sound).
A request for updated information on Threatened and Endangered Species in the area of
the facility listing was forwarded to the North Carolina Natural Heritage Program on
September 17, 1998. The response from Susan Giles of the North Carolina Natural
Heritage Program indicated that official listing of the shortnose sturgeon on the rare and
threatened species record for Martin, Bertie and Washington counties in North Carolina
is under review. Listing of the shortnose sturgeon by the North Carolina Natural
Heritage Program for other North Carolina counties is included for reference in a
supplement to Appendix A.
Additional information on the shortnose sturgeon observation in Batchelor Bay has been
provided by Harrel Johnson, District Manager of the North Carolina Division of Marine
Fisheries. This additional information is also included as a supplement to Appendix A.
The assessment endpoints discussed on pages 2-5, 4-4, and 6-5 should include an
insectivorous bird (e.g., swallow or wren species) an insectivorous mammal (e.g.,
shrew or mole species) and an amphibian or reptile. These receptors are important
for two reasons: 1) the selected species are to be used in assessment of Welch Creek,
Welch Creek wetlands, and Landfill 1 uplands and wetlands, and 2) the
bioaccumulative nature of some of the COPCs may lead to greater risk for
insectivorous (rather than omnivorous) species. The additional endpoints should be
added rather than substituted.
Welch Creek and adjacent wetlands
The ecological endpoints discussed in Sections 2 and 4, which include kingfisher, mink,
and wood duck, were identified for use as surrogate endpoints for the purpose of the
Screening Ecological Risk Assessment focused on Welch Creek and adjacent wetlands.
For the purposes of the screening level evaluation, surrogate measurement endpoint
species were dictated by site-specific considerations and the currently available data for
forage materials and prey species. The conservative Screening Ecological Risk
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Assessment concluded that potential risk to ecological receptors was presented by
Welch Creek, and as such, a site-specific ecological risk evaluation for that source area
will be conducted. Since the need for site-specific ecological risk has been determined, a
revision of the Screening Ecological Risk Assessment for Welch Creek to include
additional receptors is not warranted.
The Problem Formulation for the Baseline Ecological Risk Assessment to be conducted
for Welch Creek was documented in Section 6 of the Screening Ecological Risk
Assessment document. The Problem Formulation presented five assessment endpoints
for the site-specific baseline ecological risk evaluations. The selection of these
assessment endpoints is consistent with Ecological Risk Assessment Guidance for
Superfund: Process for Designing and Conducting Ecological Risk Assessments
(USEPA/540/R-97 /006); Region !V's Supplemental Guidance to Risk Assessment Guidance
for Superfund (RAGS): Region IV Bulletins, Ecological Risk Assessment (November 1995);
and Ecological Risk Management Principles for Superfund Sites -Draft (August 1998). The
assessment endpoints were selected to represent ecological effects in both aquatic and
terrestrial ecosystem components that may result from exposure to COPCs in surface
water and sediments and from transfer through dietary interactions. Additionally,
assessment endpoints were selected for their consistency with Ecological Risk
Management Principle #1 regarding
■ Ecological relevance -Are the species critical to sustaining the ecological structure
and function of the populations, communities, and habitats present at the site?
■ Susceptibility -Are the species exposed to site contaminants?
■ Relevance to management goals -Are the species uniquely reflective of public
concerns?
USEPA review comments suggested the inclusion of three additio.nal assessment
endpoints in the ecological risk evaluations. Specifically, the following considerations
were evaluated for each of the suggested endpoints:
■ Does the additional assessment endpoint represent a species critical to sustaining
the ecological structure and function of the Welch Creek ecosystem?
■ Will the evaluation of the additional assessment endpoints significantly supplement
the information necessary to make a risk management decision concerning the
practical need for and extent of remedial action?
■ Do the additional assessment endpoints offer evaluation of an exposure pathway
not addressed by other endpoints?
■ Do the additional assessment endpoints represent receptors of critical ecological or
socio-political significance?
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■ Is a defensible comprehensive toxicological database available to support a
quantitative risk analysis of the additional assessment endpoints?
The evaluation resulted in the inclusion of insectivorous avian species as an additional
assessment endpoint for the source area specific Baseline Ecological Risk Assessment to
be conducted for Welch Creek. This proposed assessment endpoint was added because
it represents an exposure pathway (ingestion of emergent insects) not addressed or
readily extrapolated from existing assessment endpoints in Welch Creek.
The evaluation did not support addition of either the insectivorous mammal or the
amphibian or reptile. The insectivorous mammal was considered not critical to the
wetland or creek ecosystem and did not necessarily reflect public concerns for the area.
The amphibian/reptile endpoint was not expected to modify the risk management
decisions for Welch Creek source area, did not add any new exposure pathways, nor
represent a receptor of critical socio economic significance. These assessment endpoints
were considered to not uniquely represent an exposure pathway not addressed by
current assessment endpoints.
In summary, the assessment endpoints identified for the baseline ecological risk
evaluation to be conducted Welch Creek will include
1. Maintenance of ecological health of the fresh water macroinvertebrate community,
specifically in terms of structure and function in support of higher trophic levels
2. Protection of long-term health and reproductive capacity of the fishery resources in
support of higher trophic levels
3. Protection of long-term health and reproductive capacity of predominately
piscivorous mammalian species utilizing Welch Creek and its adjacent wetlands
4. Protection of long-term health and reproductive capacity of predominately
piscivorous avian species utilizing Welch Creek and its adjacent wetlands
5. Protection of long-term health and reproductive capacity of predominately
herbivorous/insectivorous avian species utilizing Welch Creek and its adjacent
wetlands
6. Protection of long-term health and reproductive capacity of predominately
insectivorous avian species utilizing Welch Creek and its adjacent wetlands
The initial problem formulation for Welch Creek and the adjacent wetlands will be
revised based to reflect the additional assessment endpoint. The revised problem
formulation for Welch Creek will be presented in the Ecological Risk Assessment Study
Plan and Sampling and Analysis Plan (RMT, to be submitted November 1998).
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3.
4.
Landfill No. 1
In the absence of useable data, a screening ecological risk assessment for the Landfill
No.1 source area has yet to be finalized. A Screening Ecological Risk Assessment will be
performed and documented for Landfill No.1 upon receipt of validated data from the
initial phases of the Remedial Investigation (RI) characterizations of that source area.
Based on the identification of area-specific ecological COPCs for the landfill and the
adjacent wetlands, surrogate receptors will be confirmed for the source area.
Preliminary endpoints to be evaluated for selection may include those initially proposed
and possibly an insectivorous mammal (e.g., shrew or mole species).
Page 3-4. As noted in the RI/FS Work plan, there appears to be a discrepancy between
the text and figures regarding the upstream extent of wastewater solids overlying
sediments in Welch Creek.
The following text clarifies the first bullet under "Wastewater Solids and Sediment
Deposits" discussing wastewater solids and sediment deposits relative to MT-1, MT-2
andMT-3:
Thin and discontinuous wastewater solids deposits were identified
between stations MT-1 and MT-3 as indicated on Figure 3-2 of this
document.
Continuous wastewater solids deposits were identified beginning at MT-3
and continuing to the confluence of Welch Creek with the Roanoke River
as indicated on Figure 3-2 of this document.
Page 3-5. Please provide a discussion of the relative pollutant sensitivities/tolerance
of the benthic organisms sampled in Welch Creek and Conaby Creek.
The referenced text, beginning on page 3-1 and continuing through page 3-6, presents a
summary of the voluntary investigation of the lower Welch Creek surface water and
sediment conducted by Weyerhaeuser in late 1995. Additional details regarding the
study plan, rationale for sampling locations and media, in addition to complete findings
are presented in
■ RMT, Inc. November 1995. Welch Creek Risk Characterization Study, Sampling
and Analysis/Quality Assurance Workplan, Plymouth, North Carolina.
■ RMT, Inc. March 1996. Welch Creek Study Sampling and Analysis Results
Technical Memorandum No. 1, Plymouth, North Carolina.
■ Beak Consultants Limited. November 1995. Welch Creek Risk Characterization
Study, Sampling and Analysis Workplan Addendum No. 1, Biological Sampling
and Sediment Transport Monitoring, Plymouth, North Carolina.
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5.
6.
■ Beak Consultants Limited. January 1996. Welch Creek Risk Characterization
Study, Characterization of Biological Effects, Phase I, Plymouth, North Carolina.
These documents were referenced and included as attachments to the Compilation of
Existing Data Technical Memorandum (RMT, 1998a).
Supplemental and confirmational macroinvertebrate surveys are planned for the data
gathering phase of the site-specific baseline ecological risk evaluations. The results of
those surveys will be documented in the Baseline Ecological Risk Assessment Report.
The requested discussion of the relative pollutant sensitivities/tolerances of the benthic
organisms observed in Welch Creek and Conaby Creek will be included in the Baseline
Ecological Risk Assessment Report.
Table 3-1. Please include the concentration ranges of other 2,3,7,8-substituted PCDDs
andPCDFs.
As indicated in the footnote to Table 3-1, the concentration ranges presented in the table
represent Master Transect sediment core results for the standard chemical testing
program as defined for the 1995 Welch Creek Study. The standard chemical testing
program for the 1995 Welch Creek Study did not include full 2,3,7,8-substituted
dioxin/furan analysis at every Master Transect location. Three Welch Creek sediment
samples (MT-2, MT-4, and MT-7) were analyzed for the full list of 2,3,7,8-substituted
dioxins/furan congeners. The results of the dioxin/furan congener analyses were
presented in the Compilation of Existing Data Technical Memorandum (Volume 3,
Attachment 11; RMT, 1998a). Table 19 excerpted from the Welch Creek Study report is
provided with this correspondence for reference.
Table 4-1 and Appendix C.
a. Please perform internal consistency checks on the content of section 4, Table 4-1
and Appendix C. Several inconsistencies were noted during our review:
The text in Section 4 has been reviewed for consistency with Table 4-1 and Appendix C.
Text modifications have been made in response to specific and general review
comments on Section 4. A revised Section 4 of the Screening Ecological Risk
Assessment has been provided with this response.
1. For aquatic invertebrates, the text of Appendix C does not report a no
effects level of 138 ng/kg so it is not possible to determine where the range of
values reported in the summary and on page 4-2 was derived from
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Further review of the referenced literature (USEPA, 1993; Isensee and Jones,
1975; Isensee, 1978; West et al., 1994) indicated some typographical errors (e.g.,
incorrect units) for the NOAELs in aquatic invertebrates. The text on Page 4-2
has been revised to correct the units.
2. The concentrations reported in the text of Appendix C are reported as ug/kg
not ng/kg.
The concentration units for the PCDD/PCDF discussion on page 4-2 were
corrected as shown in the previous response.
3. The range of no effects and low effects tissue concentrations for fish
reported in the summary paragraph in Appendix C and on page 4-2 do not
agree.
The discussion of effect levels for dioxin/ furan on page 4-2 was reviewed for
consistency with the summary discussion in Appendix C. The range of tissue-
based NOAELs for fish are consistent with the discussion in Appendix C. The
text for invertebrate tissue effects levels has been revised to address
typographical errors in the units as outlined in the response to Comment 6(a)(l).
As a clarification for the PCB discussion on page 4-2, the NOAELs and LOAELs
that were reported are tissue-based. The discussion presented in Appendix C
(pages 1-3) included a discussion of tissue-based NOAELs and LOAELs for
invertebrates, sediment-based NOAELs and LOAELs for fish, as well as the
tissue-based NOAELs and LOAELs presented and discussed in Section 4.
4. When reviewing summaries of toxicity data for birds and mammals it was
discovered that for PCBs, the text on page 4-2 indicates that reproductive
impairment can occur in avian species from exposure to PCB, but rio levels are
provided, and no source is mentioned, yet Table 4-1 shows values from two
literature sources.
The majority of preliminary TRVs (Table 4-1) used for avian endpoints in the
Screening Ecological Risk Assessment were obtained directly from Sample et al.,
(1996). The primary reference used by Sample in TRV development is also
identified in Table 4-1. For Aroclor 1260, the preliminary TRV was derived from
the primary reference Custer and Heinz, 1980, in accordance with the procedure
discussed in Section 4.1.3. As a clarification, a revised Table 4-1 has been
prepared identifying the preliminary TRVs which were derived, and further
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references the appropriate location in Section 4 discussing the derivation.
Expanded endpoint-specific toxicity profiles will be prepared and submitted as
part of the Baseline Ecological Risk Assessment.
5. For PAHs. the text on page 4-3 discusses a study by Patton and Dieter
(1980), however, no concentrations are reported. Table 4-1 shows TRVs for
PAHs from Sax and Lewis, 1989, and Yoshikawa et al., 1985.
The Patton and Dieter (1980) study evaluated the toxicity of a PAH mixture (a
synthetic blend of aromatics commonly found in crude oil) to mallards. The
mallards were fed PAH concentrations ranging up to 4,000 mg/kg for over
7 months. The authors evaluated physiological indicators, including growth,
blood chemistry and hepatic function, and concluded that adult birds were able
to tolerate exposure to elevated concentrations of PAHs over extended periods of
time.
The preliminary TRVs for PAHs reported in Table 4-1 were low, conservative
values used for screening purposes. Derivation of the preliminary TRVs for
P AHs are summarized in Section 4.1.3.
Similar discrepancies were found for many other COPCs discussed in the text and in
Appendix C.
b. Please summarize effect data for avian and mammalian species in the text of
Section 4 and Appendix C.
For most of the CO PCs, Section 4 included a brief summary of toxicity effect data for
aquatic, avian and terrestrial species. The toxicity profile for effects in avian species for
exposure to PCDDs/PCDFs was inadvertently omitted from the Screening Level
Ecological Risk Assessment. Expanded endpoint-specific toxicity profiles will be
prepared and submitted as part of the Baseline Ecological Risk Assessment.
c. There is no full toxicity profile for PCDDs/PCDFs in Appendix C. Since many of
these may be COPCs the document should be revised to include a discussion of the
COPCs with a special emphasis on those data critical to deriving the selected TRV.
Expanded endpoint-specific toxicity profiles will be prepared and submitted as part of
the Baseline Ecological Risk Assessment.
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7.
8.
Section 4.1.2. EPA was not able to provide a review of the TRVs derivation. In order
to understand and duplicate the derivation of the TRVs, please include a summary
table which provides the following information for each chemical to be evaluated:
1. Receptor of Concern
2. Chemical form used in the literature study
3. Duration of study
4. Route of exposure
5. Study endpoint (mortality, reproductive effects, eggshell thinning, etc.)
6. Study NOAEL or LOAEL
7. Any uncertainty factors used, and rational
8. Final Toxicity Reference Value proposed for use (reported as a dose)
9. Source of data.
Table 4-1 identifies the preliminary TRVs used for surrogate endpoints in the Screening
Ecological Risk Assessment. The majority of these preliminary TRVs were obtained
directly from Sample et al., (1996), and are identified in Table 4-1 with the original
reference and the phrase "per Sample et al., 1996." For Aroclor 1260, phenanthrene and
pyrene, the preliminary TRVs were derived from the original references cited, in
accordance with the procedure discussed in Section 4.1.3. As a clarification, a revised
Table 4-1 has been prepared identifying the preliminary TRVs which were derived, and
further references the appropriate location in Section 4 discussing the derivation.
For the Baseline Ecological Risk Assessment, a detailed evaluation of the existing
toxicity data and derivation of endpoint-specific TRVs will be prepared. A summary
table, which includes the nine elements referenced in the review comment, will be
completed for the Baseline Ecological Risk Assessment, to the extent possible. The
derivation of the constituent-specific TRVs for each receptor will also be provided
consistent with the Ecological Risk Assessment guidance.
Section 4.1.2, page 4-6. Bottom of the page. This paragraph describes the use of a
body weight scaling factor, as published by Sample et al., for deriving a wildlife TRV
from a surrogate test species. EPA Region IV does not condone the use of scaling
factors in the derivation of TRVs. Please eliminate this procedure from the
document.
For the purposes of the Screening Ecological Risk Assessment the scaling factor was
assumed to be 1.0. This conservative assumption results in no modification of the
surrogate test species TRV in deriving a wildlife TRV.
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9.
10.
11.
Section 4.1.2, page 4-7. Bottom of the page. EPA questions the use of toxicity results
for a mammal in evaluating toxicity to birds. EPA recommends a more thorough
review of the avian toxicity literature to locate values that are more appropriate for
evaluating effects to fish-eating and omnivorous bird species.
As discussed in the response to comment #7, A detailed literature review for each
assessment endpoint species will be performed to arrive at TRVs for use in the Baseline
Ecological Risk Assessment.
Section 4.3. Given the nature of many of the Site CO PCs and their potential to bind
to sediments and to biomagnify, it would be appropriate to evaluate the pathway
from sediment to bottom dwelling fish to mink in the analysis. This will serve two
functions. First, potential risks can be estimated to the fish, which are likely to be
exposed to COPCs partitioned into the sediment. Second, collection of catfish or carp
and subsequent tissue analysis will provide site specific data for estimating actual
doses to mink.
Selected measurements endpoints for the ecological risk assessment were chosen to
represent the higher trophic levels of the source area ecosystems in an effort to address
both the direct toxicological and the bioaccumulative and biomagnifying properties of
the COPCs. These endpoints include piscivorous avian and mammal species. Inputs to
the evaluation of potential risks posed to these specific endpoints will include analysis
of fish tissue. Whole fish for analysis will be collected from Welch Creek with methods
designed to collect bottom dwelling fish in addition to gamefish since it is unlikely that
the selected piscivorous endpoints will feed exclusively on bottom dwelling fish.
Results of the fish collection and analyses will be used in coordination with dietary
exposure modeling assumptions.
Table 4-3. The Wildlife Exposure Factors Handbook does not include wood duck
data. Please provide a source for the input parameters for this species.
The footnotes of Table 4-3 have been revised to clarify the references used to provide
input parameters of the wood duck diet composition. The specific references are
presented below.
Bellrose, F.C. 1980. Ducks, Geese and Swans of North America. A Wildlife
Management Institute Book. Stockpole Publishers. Harrisburg, Pennsylvania.
Beyer, W.N., E.E. Connor, and S. Gerould. 1994. Estimate of Soil Ingestion by Wildlife.
Journal of Wildlife Management Volume 58, Issue 2; pages 375-382.
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12.
Terres, J.K. 1991. The Audubon Society Encyclopedia of North American Birds. Wings
Books. New Jersey.
Table 4-4. A few discrepancies were noted when reviewing this Table in comparison
to Appendix F of Volume 3; Attachment 8 of the Compilation of existing data tech
memo;
1. The high concentration of nickel in sediment should be 64.5 mg/kg
(sample #MT06MP-40-10N).
2. The high concentration of copper in sediment should be 95.1 mg/kg
(sample #MT04MP-40-3S).
3. The high concentration of chromium in sediment should be 2,740 mg/kg
(sample# MT0SMP-70-14S).
4. The high concentration of mercury in sediment should be 12.9 mg/kg
(sample# MT06MP-40-04S).
5. The high concentration of phenanthrene in sediment should be 0.62 mg/kg
(sample# MT04MP-40-3S).
Section 4.3.3 describes the development of exposure point concentrations for the
environmental and biological media under evaluation. The exposure point
concentrations for sediment reflects the maximum observed COPC concentrations in
surficial sediment samples representing the sediment zone available to endpoint
species. The sample locations referenced in the review comment above represent
samples collected from 3 to 14 feet below sediment surface. A specific list of surficial
sediment sample locations used in the ecological risk assessment are provided in
Table B-3 to be included as a supplement to Appendix B.
Also, please cross check Table 4-4 with Table 3-1 and 3-3. Some values listed as high
range detections in Table 3-1 and 3-3 were not used consistently in Table 4-4.
As presented previously, the exposure point concentrations presented in Table 4-4 for
sediment reflects the maximum observed COPC concentrations in surficial sediment
samples. Table 3-1 presented a summary of sediment concentrations from the 1995
Welch Creek study irrespective of depth interval.
The 2,3,7,8-TCDD toxic equivalent concentration (TEQ) presented in Table 4-4
represents the toxic equivalency of dioxin and furan congeners present at Welch Creek
and wetland sediment and wetland surface water locations with the maximum
observed 2,3,7,8-TCDD concentration. 2,3,7,8-TCDD was not detected in Welch Creek
surface water samples collected and analyzed using the standard chemical testing
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13.
14.
program of the 1995 Welch Creek Study. As a result, the 2,3,7,8-TCDD TEQ presented
in Table 4-4 represents the creek surface water location with the maximum observed
2,3,7,8-TCDF concentration. Appendix E of the Screening Ecological Risk Assessment
presents details on TEQ calculations for environmental media and biological tissues. By
contrast, Table 3-1 and Table 3-3 present observed ranges of 2,3,7,8-TCDD and
2,3,7,8-TCDF concentrations.
The exposure point concentrations presented in Table 4-4 are correct based on the stated
criteria. A revised Table 4-4 with clarified footnotes is provided.
Table 4-4. Please provide a description for how the COPCs included in Table 4-4
were selected. Several detected compounds listed in Appendix F (above citation)
were excluded from Table 4-4. Please explain. Also, please list the sample numbers
used in the risk assessment in Table 4-4 for cross reference.
Preliminary COPC selection process for the screening ecological risk assessment is
documented in Section 3.2 and with additional details provided in Appendix B.
Preliminary COPC selection was performed by evaluating the maximum detected
concentration of each constituent with the appropriate USEPA Region IV ecological
screening value. This evaluation was conducted for each constituent in each
environmental medium that was sampled.
For those constituents that did not have a Region IV ecological screening value, a
surrogate ecological screening value was substituted or was calculated using recognized
methodologies. The preliminary ecological COPCs for Welch Creek and the adjacent
wetlands were initially presented on Table 3-4.
A revised Table 4-4 with clarified footnotes is provided. In addition a new table,
Table 4-4a has been prepared and provided. Table 4-4a is a companion table to Table
4-4 and presents sample locations which correspond to the maximum observed
concentration of the constituent presented on Table 4-4.
Section 5-general. Assessment endpoint #5 should be amended lo include further
characterization of aquatic insects and other invertebrates for COPC concentrations.
Assessment endpoints have been revised as presented in the response to Comment #2.
The Ecological Risk Assessment Study Plan and Sampling and Analysis Plan will include a
discussion of revised assessment and measurement endpoints and in addition to a
presentation of planned characterizations of insects and invertebrates as appropriate to
support dietary exposure modeling for insectivorous endpoints.
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15.
16.
17.
18.
19.
20.
Page 4-14. Bottom paragraph, fourth line from bottom. Please change PAHs to PCBs.
The text has been modified as requested. A replacement page 4-14 is included with this
correspondence.
Page 5-4. Please modify the discussion of wood duck modeling results to reflect the
invertebrate pathway rather than forage fish.
The text has been modified as requested. A replacement page 5-4 is included with this
correspondence.
Page 5-6. Please include a discussion of how the absence of food web data affects the
model for the kingfisher, mink, and wood duck in Welch Creek wetlands
uncertainties evaluation.
The text of the uncertainty analysis section (Section 5.3) has been modified as requested.
A replacement page 5-6 is included with this response.
Figure 6-1. Affected sediments should be added to the list of contaminant sources in
the conceptual model for Welch Creek and adjacent wetlands.
Figure 6-1 has been modified as requested. A replacement Figure 6-1 is included with
this response.
Appendix B, Table B-1. Please provide a reference for the screening value for
2,3,7,8-TCDD used. The value of 0.0000025 mg/kg is not included in the 1995 EPA
Region IV screening value table.
The reference for the screening value for 2,3,7,8-TCDD of 0.0000025 mg/kg is provided
below:
USEPA. March 1993. Interim Report on Data and Methods for Assessment of
2,3,7,8-tetrachlorodibenzo-p-dioxin risks to Aquatic Life and Associated Wildlife.
EPA'/600/R-93/055.
Appendix G. Tables G-1, G-2 and G-3. The exposure point concentration for
2,3,7,8-TCDD in fish of l.04E-04 mg/kg is inconsistent with the value of 16 ng/kg
presented in Table 3-2. If the TEQ equivalent concentration of TCDF is added then it
would be slightly higher. Similarly, the 2,3,7,8-TCDD exposure concentration in
aquatic invertebrates is given as 2.28E-04 mg/kg in Tables Gl-G-3, yet the highest
concentration in Table 3-2 is 27.6 ng/kg. Please clarify the discrepancies.
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The exposure point concentrations for fish and invertebrate tissue reflect
2,3,7,8-TCDD TEQs for the fish and invertebrate samples from the 1995 Welch Creek
study (presented in Table 3-2) with the maximum observed 2,3,7,8-TCDD concentration.
Appendix E, specifically Table E-3, presents the TEQ exposure point concentration
calculations for fish and invertebrate tissue. TEQ exposure point concentration
calculations involve conversion of wet weight concentrations to dry weight
concentrations followed by conversion to 2,3,7,8-TCDD TEQs. The calculated
2,3,7,8-TCDD TEQs for fish and invertebrate tissue are 104 ng/kg and 228 ng/kg,
respectively. Following this approach, the TEQ exposure point concentrations for fish
and invertebrate tissue presented in Table 4-4 and Tables G-1, G-2, and G-3
(1.04 x lQ-4 mg/kg and 2.28 x lQ-4 mg/kg, respectively) are consistent with those
calculated in Appendix E.
Units for ingestion rate in Table G-1 for aquatic invertebrates should be mg/kg-day.
The table has been modified as requested. A replacement Table G-1 has been provided
with this response
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Comment#l
Comment#5
Comment#6
Comment#12
Comment#13
Comment#lS
Comment#16
Comment#17
Comment#18
Comment #20
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Attachment 2
Replacement Pages and Tables
Additional information on shortnose
sturgeon from
■ NC Heritage Program
■ NC Division of Marine Fisheries
Provided as a supplement
to Appendix A
Table 19 Excerpted from Welch Creek Sampling and Analysis Study
Results Technical Memorandum #1, Weyerhaeuser Company, Martin
County, North Carolina. RMT, Inc. March 1996.
Revised Section 4
Revised Table 4-1
New Table B-3
List of surficial sediment sample locations
Revised Table 4-4
Additional Table 4-4a
Revised text on page 4-14
Revised replacement page 5-4
Revised replacement page 5-6
Revised replacement Figure 6-1
Revised replacement Table G-1
Revised replacement
Section 4 provided
Provided as a supplement
to Appendix B
Included in revised
replacement Section 4
Included in revised
replacement Section 4
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Table 19
Total Dioxin and Furan -Master Transect Samples
lllllli .. •twr~-4:¾~t':~p ,;It{}'' . ,~~,,i!,illwta frdia! t¼1/k4,l:0-~ ., .
2,3, 7.8-TCOD (ng/kal 2.03 1636 3.77 4.17 1,2.3.7,8-PECOD lna/kal < 1.16 49.0 <2.45 < 0.96 1,2,3.4, 7,8-HXCDD nn/kr 3.74 < 3.26 < 1.46 5.04 1.2, 3, 6, 7. 8-HXCDD no/ke 6.95 495 6.07 71.2 1.2,3,7,8.9-HXCDD no/kc 14.8 222 4.92 15.6 1.2,3.4,6,7,8-HPCDD (ngtko1 317 1430 142 3050 OCDD I no/ko l 12849 Ei 14318 Ei 4544 60587 Ei 2.3, 7,8-TCDF lna/ka 14.4 11839 Ei 20.6 13.1 1.2.3, 7,8-PECDF nc kal < 0.44. 62.3 13.9 < 1.23 2.3.4, 7.8-PECDF n kal < 0.48 70.2 6.08 < 1.44 1,2,3,4,7,8-HXCOF na/ko> <0.37 11.5 19.7 16.7 1,2, 3,6, 7,8-HXCDF ng/ko, < 0.32 4.60 5.46 5.94 1 ,2,3, 7,8,9-HXCDF no/kn < 0.34 < 1.90 < 0.66 < 0.81 2,3,4,6, 7,8-HXCDF n /kn 1.30 10.2 3.90 12.5 1,2,3,4,6,7,8-HPCDF no 11,01 2.04 71.3 36.0 728 1,2.3,4,7,8,9-HPCDF no /HOI <0.42 8.20 7.88 50.3 OCDF ( nn/kn 1 4.06 233 64.8 1225 Total TCDD /no/ko> 13.0 1814 20.2 22.5 Total PECDD no/ka 8.96 412 NR NR Total HXCDD no/kc 153 2591 38.5 1424 rotal HPCDD na/k, 663 2791 393 8467 Total TCDF In :vko1 25.3 21229 37.2 36.4 Total PECDF nq/ko, NR 344 46.3 46.4 Total HXCOF no/kol 2.06 145 49.3 630 1otal HPCOF nOfknl 2.04 219 124 2805 Total Oraanic Carbon/%) 8.3 28.2 7.6 3.4 Note:
Native -Native Sediment ' WWS -Wastewater Solids
NR -Not Reoorted
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State of North Carolina
Department of Environment
and Natural Resources
Division of Marine Fisheries
James 8. Hunt, Jr., Governor
Wayne McDevitt, Secretary
Preston P. Pate, Jr., Director
Ms. Roxie Allison-Browne
NOAA Office Assistant
General Counsel for Fisheries
1325 East-West Highway
Room 11360
Silver Springs, Maryland 209 I 0
Dear Ms. Allison-Browne:
June 9, 1998
~ ,;-~;,. .. • ___ a
NCDENR
Ncf.rl')\ CA,,:.~1.t.""' r..,:-,a.w, >4to:H r 0, ►:NV,qc"'HM~ ·""' NATl.-:r•t. n,._.....,._,;v:~
I am writing to you as per your request. This letter is to certify that on April 18, 1998 the second documented capture ofa short nose sturgeon in the Albemarle/Roanoke system of North Carolina occurred. This is the first documented capture in over a hundred years in this system. The sturgeon was taken in gill nets that are fished as part of an ongoing fisheries independent sampling program for striped bass in the Albemarle/Roanoke system conducted by the North Carolina Division of Marine Fisheries. The sturgeon, which was a 652mm FL mature male, was taken in the vicinity of Avoca Farms in Batchelor Bay, near the mouth of Roanoke River. Identification of the sturgeon has been confirmed by personnel from N.C. State University, and U.S. Fish and Wildlife Service Cooperative Unit. I have included a Xerox copy of a photograph of the sturgeon next to an Atlantic sturgeon that was taken around the same time. The short nose is the one on the left of the photograph. The specimen has been preserved and will be transferred to the North Carolina Museum ofNarural Sciences in Raleigh, North Carolina. I hope that this information will be of some assistance to you.
HBJ/kh
Cc: David Taylor
Preston Pate
Frank McBride
Wilson Laney
~1e•'f:'.-"
Sincerely,
Harrel B. Johnson
District Manager
P. 0. Bax 769, Morehead City, North Carafina 28557--0769 Telephone [phone] FAX [phone] An Equal Opportunity Affinnalive Action employer 50'1!, recycled/ 1 O'i!, post-consumer paper
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Shortoo1e sturgeon
Aclpenser brevirostrvm
E'mlangl'ffd. (March 11, 1967)
Deacription: The shortnose BtUJiGOD bas five rws of bony plates (l dorsal, 2 lawal, and 2 wntral)
separated by naked skin that nms dm lmgrh of the body, a 1llil with 1luo upper lobs larger and longer
than the lower, and mur barbels (lib droopy whiskers) along the mouth locaUd undi:z-a kmg poimed
Sll0Ut. This sturgeon has a blackish htlad aud baak, ydlowish-brown body, pale llllllcrsidc, and grows
to about 39" (1 m) lcm,g. Young individuals haw btOGhc:s of darbr color. The slmr!Jlaso stwgcan
resanblcs YDUDS Atlantic stui:s-(A. ,s:yri,ynchru), but can be distinguished by its shorter SllOUt,
wider mouth (mouth widlh grater than 62% of dislancc, betw1!cn ;y=s), and the usual lack of bony
plates betwa:u the anal fill base 11114 the '4=al row of plates. Life History: This fish fnOVC9 from the
ocean and c:snaaria into frcshwatirr riwrs to spawn bllt'WIICD Febl"IW')' and May. Iuwnlles may remain
upriver tw up to s years aftar birth bofbn, MigratinJto tho ocean. Fmtll on wom,s, ~ inscd
lmvae, small clams, small fish, and stems and lcbes of ma,:rophyte. ll is malUnl at 3 )'CU'S of age, and
may Jive fur up to 30 yaars. H1bltat: A bettam dwdl1:1r, shol'IDOse st11igean prefets deep watec with
soft submatc and wgcwad bonoros FOUDd in ocean and csniarics, at spawnillg Rquinss freshwatcc
of inland portions of rivers with fast c;um,nt and rougn bot!Dms. According to Jad<son i:t al. ( 1992),
the fish usually gather in deep spots during the day and move to tidal flats for thc night, in the summer
a.od early fall. Distribution: This fish is mwid along the Atlantic coast from New Brunswick.to
Florida. Historically, shortnoso sturg=,o were widoly reported from N. C. rivers. Cum:nt distnbution
is not well known. This species is beliawd to occ;,ur iJ:i &ho Cape Fl'M River draillage and Albemarle
Soµnd, and a.n U11t.0nfirmcd report exists for Pamlioo Spund. Most recent rqx>rts have coma from the
Capo Fcax River naa;r Wilmington. Also, it has been found in 1lu, Poe Dee R.iwr and in tha Roanoke
"'Rmir, not &r from the ri..,.,t'• mouth. Rccanls CilU8t for sisl!tings m Ansc;,n, Bladeu, Brunswick,
Columbus, N,;w Hanovc:r, Pender, and Ridunolld I.OWlqcs. Threats: OV=fishing and degradation af
waterways. Rrco-datioos: Enfotcc:ment ofpn:,tadivo lsws regarding fishing and wall:r quality
n,gulation.
Sources: Jackson et al.1992, Mipogno pers. comm., Ross 1988.
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Section 4
Screening Ecological
Effects and Exposure Evaluation
This section presents information related to the preliminary ecological effects evaluation and
preliminary exposure evaluation for the RI/FS focus areas at the Weyerhaeuser Company
Martin County facility. As required by applicable USEP A guidance (USEPA, 1997), this section
incorporates ecotoxicity profiles, toxicity reference values, and other conclusions relevant to the
performance of a screening ecological risk assessment. The ecotoxicity profiles that have been
provided for the identified COPCs have not received critical site-specific or scientific review.
Furthermore, applicable USEPA guidance (USEPA, 1997), requires the use of the most
conservative toxicity reference values and assumptions contained in the guidances and as such,
conclusions reached in this screening ecological risk assessment may not be indicative of the
actual exposure of ecological receptors to the COPCs.
4.1 Ecotoxicity Evaluation
The preliminary ecological effects evaluation focuses on toxicity profiles and developing
toxicity reference values (TRV) for site-related ecological COPCs as they apply to the relevant
ecological species. Consistent with the guidance for screening ecological risk evaluations
(USEPA, 1997), emphasis is placed on direct contact and ingestion pathways, given the
species-specific TRV information available for these pathways.
4.1.1 Summary of COPC Ecotoxicity Profiles
Ecotoxicity profiles and TRVs were obtained from the literature sources set forth in
Section 7 and Appendix C. Ecotoxicity profiles describe the toxic mechanism or action
of a constituent and the dose or environmental concentration which causes a specified
adverse effect for the exposure route being evaluated. As required by applicable
USEPA requirements and documents, the following text presents the ecotoxicity profiles
which summarize published scientific findings and agency perspectives regarding
ecotoxicity for the preliminary site-related COPCs. Additional site-specific and
scientific review of these documents will be incorporated into the site-specific ecological
risk assessment as needed. Additional information on the ecotoxicity and a preliminary
compilation of reference sources for aquatic and terrestrial effects of site-related COPCs
are presented in Appendix C.
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Dioxins/Furans
There are 75 isomers of polychlorinated dibenzo-p-dioxins (PCDDs) that differ
in the number and position of attached chlorine atoms; each isomer has its own
unique identity and toxicological properties. Furans have a similar chemical
structure to dioxins but are, in general, less toxic.
Based on the review of available data, USEPA (Wildlife Exposure Factors
Handbook, 1993) derived environmental concentrations associated with
2,3,7,8-TCDD risk to aquatic life. Tissue-based No Observed Adverse Effects
Levels (NOAELs) for fish range from 0.021 to 0.67 ug/kg, while Lowest
Observed Adverse Effects Levels (LOAELs) range from 0.765 to 2,042 ug/kg.
In aquatic invertebrates, tissue-based NOAELs range from138 to 1,570 µg/kg.
There are no sediment-based concentrations of TCDD that have been reported
to cause mortality of benthic invertebrates or alteration in benthic communities.
Polychlorinated Biphenyls (Aroclor, PCBs)
Both fish and aquatic invertebrates accumulate and bioconcentrate PCBs
(Lowe et al., 1972; Sanders and Chandler, 1972; Courtney and Langston, 1978;
Kennish et al., 1992). In addition, toxicological tests have demonstrated adverse
effects on survival, growth, and reproduction.
Based on a review of the available literature, the most sensitive endpoint for
PCBs in fish appears to be reproductive success, particularly reduced
fecundity. In fish, tissue-based NOAELs for PCBs range from 0.1 to 102 mg/kg
and LOAELs range from 0.6 to 289 mg/kg.
Terrestrial invertebrates appear to be tolerant of PCB in soils. Studies by
Larsen et al. (1992), and Diercxsens et al. (1985), reported that PCBs at
concentrations as high as 150 mg/kg were not toxic to worms. Lumbricus
rubellus was exposed to the PCB combination for 2 days then transferred in
1.5 mg/kg Askarel-containing soil for 60 days with no reported toxicity.
Several studies have been conducted on the sublethal effects of PCBs in avian
species, including enzyme induction, endocrine and growth effects, immune
system effects, mutagenicity, reproductive impairment, and teratogenicity.
While effects such as hepatotoxicity and neurotoxicity have been observed in
the laboratory at high PCB doses, the most prevalent effect observed in the
field is reproductive impairment. In general, avian populations are most often
monitored by examining differences in population levels or reproductive
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success over time (Erwin et al., 1981) or among study sites (Burger and
Gochfeld, 1990).
Studies of the toxic effects of PCBs in mammals have demonstrated that PCBs
are not as toxic following acute exposures as they are following long-term
exposures to lower concentrations of PCBs (Ringer, 1983). However, in both
acute and chronic exposure situations, the mink appears to be the most
sensitive mammal to the effects of PCBs {Aulerich and Ringer, 1977).
Polycyclic Aromatic Hydrocarbons
Sediment concentrations associated with the potential for impacts to aquatic
invertebrates and fish have been established for many individual Polycyclic
Aromatic Hydrocarbons {PAHs). In addition, values have been derived for
total P AHs, as well as for low molecular weight and high molecular weight
groups of PAHs. Sediment quality guidelines for total PAHs range from
2.9 mg/kg (MacDonald, 1993) to 44.8 mg/kg {Long et al., 1995).
Very little information is available regarding tissue concentrations associated
with adverse effects to aquatic organisms for PAHs. A wide range of
sediment-based concentrations for individual PAHs have been reported, based
on mortality in benthic invertebrates. A NOAEL of 2.9 mg/kg in sediment has
been reported for total P AHs.
Limited information was available on the toxic effects of PAHs in birds. A
study by Patton and Dieter (1980) evaluated the toxicity of a PAH mixture
representative of the aromatic fraction of crude oil to mallards. The study
evaluated dietary exposure for up to 7 months with maximum PAH
concentrations of 4,000 mg/kg. Short-term physiological effects (e.g., body
weight changes, hepatic function) were observed with the test birds developing
tolerance upon continued exposure·.
Chromium
Trivalent chromium is an essential element to man and wildlife, playing an
important role in insulin metabolism {Larngard and Norseth, 1979).
Hexavalent chromium is more toxic than trivalent chromium because of its
high oxidation potential and the ease with which it penetrates biological
membranes (Steven et al., 1976; Taylor and Parr, 1978). Chromium is unlikely
to biomagnify within the food chain due to its decreased bioavailability by
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humic acid (ATSDR, 1991). In most soils, chromium is primarily present as
precipitated trivalent chromium which is not bioavailable.
Effects due to exposure to sediment-bound chromium may occur over a wide
range of concentrations, although the most adverse toxic effects are associated
with the hexavalent form of this element.
Several studies of the effects of chromium on terrestrial wildlife have also been
co1;ducted. The results of these studies with avian receptors have been
inconclusive. Gilani and Marano (1979) did report decreased egg viability and
increased frequency of malformed embryos from exposure to hexavalent
chromium. Similarly, studies with mammals have found that high
concentrations of chromium are mutagenic, teratogenic, and carcinogenic
(Eisler, 1986).
Copper
Physical, chemical, and biological factors substantially influence the effects of
copper because numerous compounds, including several metals, interfere with
the absorption, distribution, and excretion of copper by competing for common
binding sites (ATSDR, 1990b). The physicochemical form of copper is also
important in considering its environmental behavior as well as its
bioavailability to organisms. Copper bound in mineral lattices tends to be
unavailable and is unlikely to have ecological significance.
Several researchers have demonstrated that exposure to relatively high
concentrations of sediment-bound copper is lethal to a variety of aquatic
organisms (Maleug et al., 1984; Long et al., 1990).
Copper in soil and sediment has also been shown to be toxic to terrestrial
wildlife on a species specific basis. Based on the results of Aulerich et al. (1982),
wildlife toxicity reference values for copper have been calculated.
Mercury
Mercury is a potentially toxic metal that has become a widespread
environmental contaminant. Mercury, particularly organically complexed
forms, can bioconcentrate in organisms and bioaccumulate through food
chains. Because mercury can accumulate in aquatic food webs, predation on
mercury-containing aquatic organisms provides another pathway for
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potentially toxic exposures to mercury for both aquatic and terrestrial
predators.
Available sediment quality guidance for mercury range from 0.1 mg/kg to
0.71 mg/kg, based on concentrations reported to cause acute mortality to
benthic invertebrates, and disrupt or alter benthic communities. Tissue-based
LOAELs for fish reportedly range between 1 and 4.47 mg/kg. For other
species, such as zooplankton and grass shrimp, the range of LOAEL values is
slightly lower, ranging from 0.02 to 1.1 mg/kg.
Mercury is also considered a mutagen and teratogen to terrestrial wildlife
causing embryocidal, cytochemical, and histopathological effects at elevated
exposures. Concentrations of total mercury that are lethal to sensitive wildlife
species range from 4,000 to 40,000 µg Hg/kg food for dietary doses to birds,
and 1,000 to 5,000 µg Hg/kg food for mammals (Eisler, 1987b).
Nickel
Nickel is an essential micronutrient for all living organisms; however, at high
concentrations nickel may adversely affect many animal species. Physical,
chemical, and biological factors substantially influence the effects of nickel.
Compounds such as copper tend to interfere with the absorption, distribution,
and excretion of nickel by competing for common binding sites (ATSDR, 1997).
The speciation and physicochemical form of nickel is also important in
considering its environmental behavior as well as its bioavailability to
organisms.
Available sediment quality guidelines for nickel range from 15.9 to 51.6 mg/kg
based on concentrations reported to cause acute mortality to benthic
invertebrates, and disrupt or alter benthic communities.
Several investigators have considered acute and chronic toxicity from exposure
to nickel by avian and mammalian receptors. Based on a study using mallards
(Cain and Pafford, 1981), test-species doses of 54.8 mg Ni/kg bw-day
(NOAEL,) and 75.7 mg Ni/kg bw-day (LOAEL,) have been calculated.
Zinc
In aquatic environments, zinc commonly occurs in suspended and dissolved
forms in surface water, and partitions to sediment or suspended solids through
sorption onto hydrous iron and manganese oxides, clay minerals, or organic
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0 material. Zinc may bioaccumulate in aquatic animals from water, ingestion of
particulate matter, and ingestion of food at 51 to 1,130 times the concentration
present in the water (ATSDR, 1994g). However, studies indicate, in general,
that zinc does not biomagnify through food chains (ATSDR, 1994g).
Studies conducted on the toxicity of 20,000 mg zinc/kg feed metallic zinc or
zinc salts to birds reported that chlckens, mallards, and Japanese quail
displayed symptoms of decreased fertility, gastric, hepatic, and renal effects.
Exposure to hlgh levels of zinc in the diet prior to, or during, gestation has been
associated with increased fetal resorption, reduced fetal weights, altered tissue
concentrations of fetal iron and copper, and reduced growth in the offspring
(ATSDR, 1994b).
4.1.2 Method for Derivation of Toxicity Reference Values
TRVs are species-specific effect levels whlch have been derived from laboratory studies
and are defined in the Ecological Risk Assessment Guidance (USEPA, 1997) as screening
level ecotoxicity values.
The NOAEL is a TRV whlch expresses the hlghest exposure level at which no adverse
effects have been demonstrated. The Lowest Observed Adverse Effects Level (LOAEL)
is a TRV that expresses the lowest exposure level or dose shown to produce adverse
effects such as reduced growth, impaired reproduction, or increased mortality.
Applicable USEPA Guidance (USEPA, 1997) requires that screening-level ecological risk
assessments rely on the most conservative TRV available from the literature for the
chemical and surrogate species under consideration. If the LOAEL is the only TRV
available for a contaminant, then applicable USEPA guidance (USEPA, 1997) requires
that the NOAEL should be estimated by dividing the LOAEL by 10.
For some surrogate ecological receptor species, TRV literature values were unavailable.
Alternate values for a species in the same or closely related ecological receptor group
that the site habitat could support may be used in thls situation (USEPA, 1997). This is
acceptable at the preliminary evaluation point in the process, but increases the level of
uncertainty in screening ecological risk results.
Sample et al. (1996), and recent unpublished work by Sample indicate that "simple"
body weight scaling is most appropriate for most mammals and most chemicals,
although chemical-specific scaling factors should be employed where available. For the
purpose of deriving "screening-level" TRVs, a body weight scaling factor of 1.0 was
employed. Consistent with Sample et al. (Page 4, 1996), the equation for deriving a
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wildlife TRVs raises the ratio of body weights (bw) of test and wild species to the power
of one minus the scaling factor.
The appropriate equation for simple body weight scaling is presented below:
NOAELw = NOAEL, x [bwi/bww]ll-sca!ing !actml
where:
NOAELw
NOAEL,
bww
bw,
NOAEL for wildlife species
NOAEL for test species
body weight for wildlife species
body weight for test species
If the scaling factor is assumed to be 1.0, the equation reduces to:
NOAELw = NOAEL,
4.1.3 Constituent-Specific Toxicity Reference Values
Constituent-specific TRVs for the ecological COPCs identified for source areas at the
Weyerhaeuser Company Martin County facility are presented by screening ecological
endpoint species in Table 4-1. These preliminary TRVs were obtained from Sample et
al., (1996), unless otherwise noted in Table 4-1. If body weight scaling was employed by
Sample et al., (1996) in derivation of a wildlife TRV, the TRV for the test organism was
used as conservative toxicity values for this Screening Ecological Risk Assessment.
Additional clarifications and assumptions related to the development of constituent-
specific TRVs are presented in the following narrative.
■ The TRV for Aroclor 1260 for birds is based on a study of the reproductive effects of
Aroclor 1254 on mallards, conducted by Custer and Heinz (1980). The study
yielded a dietary NOAEL of 25 mg/kg. This value was converted to 1.34 mg/kg-
bw-day by multiplying it by the food ingestion rate for mallards [calculated to be
0.056 kg/ day based on Nagy's (1987) allometric equations cited by USEPA (1993)]
and the inverse of the female mallard's body weight [1.043 kg per Nelson and
Martin (1953) as cited in USEPA (1993)].
■ The TRV for phenanthrene was derived from a LDso study using rats (Sax and
Lewis, 1989). An uncertainty factor of 0.01 was used to convert the LDso dose to a
NOAEL, which was multiplied by the daily ingestion rate of the mink to yield the
TRV. In the absence of data on avian species, the results of Sax and Lewis were also
used for the wood duck.
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■ The TRV for pyrene was based on the results of a study by Yoshikawa et al. (1985),
using rats. An uncertainty factor of 0.1 was used to convert the LOAEL to a
NOAEL, which ~as multiplied by the daily ingestion rate of the mink to yield the
TRV. In the absence of data on avian species, the results of Yoshikawa et al., were
also used for the wood duck.
4.2 Fate and Transport of Preliminary COPCS
The following text presents a synopsis of the literature on fate and transport characteristics for
site-related COPCs. Table 4-2 summarizes envirorunental fate and transport parameters for
screening ecological COPCs. Additional information on COPC fate and transport is presented
in Appendix D. A more detailed assessment of the COPC fate and transport will be performed
as part of the RI Report and Quantitative Risk Assessments.
Dioxins/Furans
The fate and transport of dioxins has been summarized by A TSDR (1997a). The
following briefly summarizes the factors most relevant to the Site and screening level
risk assessment.
■ The PCDDs/polychlorinated dibenzofurans (PCDFs) congeners vary in their water
solubilities, potential for volatilization, solid phase partitioning, and potential for
bioaccumulation, chiefly based on the amount of chlorination and to a lesser extent,
their chlorine substitution pattern.
■ The low water solubility, low volatility, and high affinity for organic material
causes dioxin compounds to partition out of the aqueous and gaseous phases and
adsorb strongly to organic materials. In surface water, dioxin tends to be removed
from the aqueous phase and deposited in organic bottom sediments.
■ In soils, PCDD /PCDFs adsorb to the soil matrix. Therefore there is little potential
for leaching to the groundwater, unless the groundwater contains elevated
concentrations of dissolved organic carbon.
■ Adsorption is the major factor controlling PCDD /PCDF transport and
bioavailability in the envirorunent. Adsorption is positively correlated with the
organic carbon content of the soils and sediments, with the greater the adsorption
the lower the bioavailability.
■ Although PCDDs/PCDFs are highly persistent, volatilization and photolysis can
occur as major removal processes. The lower chlorinated congeners (i.e., those with
three or fewer chlorines) are more amenable to volatilization and photolysis than
the higher chlorinated congeners.
■ PCDDs/PCDFs are resistant to biological breakdown, and tend to readily
accumulate in fatty tissues when taken up by the organism.
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Polychlorinated Biphenyls (PCBs, Aroclors)
The fate and transport of PCBs has been summarized by ATSDR (1997b). The following
briefly summarizes the factors most relevant to the Site and screening level risk
assessment.
■ Aroclor PCBs vary in their water solubilities, potential for volatilization, solid phase
partitioning, and potential for bioaccumulation, chiefly based on the amount of
chlorination and relative amounts of homologues in the Aroclor mixture.
■ The low water solubility and high Kow indicate that PCBs will have a strong
tendency to adsorb to soil and sediment particles. Adsorption is further enhanced
by the presence of organic matter, clay or microparticles onto which PCBs can
partition. As a result, soil leaching is expected to be greatest in soils with low
organic carbon levels. Adsorption and leaching potentials will also depend in part
on the level of chlorination: the more chlorinated a PCB, the more it adsorbs and the
less it leaches.
■ The major routes of PCB removal from water and soil are volatilization and, to a
more limited extent, biological degradation. Adsorption and desorption of PCBs to
soils or sediments are dependent upon the organic carbon content of the solid
matrix, as well as other factors such as temperature.
■ Once in the atmosphere, PCBs can potentially undergo additional -transport in the
air. Atmospheric removal occurs via two major routes: photolysis (typically only
with vapor-phase PCBs) and wet or dry deposition (particulate-phase PCBs).
Oxidation is not expected to represent a significant removal process.
■ PCBs have the potential to partition from water into aquatic organisms, including
fish. Measured bioconcentration factors (BCFs) in aquatic animals range from 104 to
106, with higher relative partitioning observed in lipid-rich species. The
bioaccumulation potential of PCBs may increase with higher chlorine substitution
and lower water solubility. PCBs have also been shown to biomagnify both in
aquatic and terrestrial food chains.
■ PCBs which have become sequestered in deep sediments appear to effectively
decrease the amount of PCB available for further dissolution and transport in
aquatic environments.
Polycyclic Aromatic Hydrocarbons (P AHs)
The fate and transport of PAHs has been summarized by ATSDR (1993). The following
briefly summarizes the factors most relevant to the Site and screening level risk
assessment.
■ In general, PAHs vary in their water solubilities, potential for volatilization, and
sorption characteristics, chiefly due to molecular weight and number and
orientation of the benzyl rings.
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0 ■ Despite their high lipid solubility, most P AHs show little tendency to biomagnify in
food chains, principally because they are rapidly metabolized in most biota.
■ In surface waters, P AHs may be removed by volatilization, adsorption to
suspended solids or sediments, photodegradation, degradation by biota, or by
accumulation in biota which cannot biodegrade the P AHs. They are predominantly
associated with suspended particulate or dissolved organic carbon in aquatic
systems.
■ Low molecular weight PAHs (i.e., those with molecular weights less than
220 g/mole), which have higher Henry's Law constants, will tend to volatilize more
readily than the higher molecular weight PAHs. The higher molecular weight
PAHs have lower Henry's Law constants, higher Koc values, and a tendency to
bioaccumulate (if not metabolized) and preferentially adsorb to soils and sediments
compared to the lower molecular weight P AHs.
Chromium
The fate and transport of chromium has been reviewed by several authors (ATSDR,
1991; Bodek et al. 1988; and USEPA 1979). The following briefly summarizes the factors
most relevant to the Site and screening level risk assessment.
■ Chromium is a naturally occurring metal. The three most stable valence states of
chromium are 0, +3, and +6. Chromium exists in the atmosphere primarily as
particulate matter which may be deposited on land or water by means of wet and
dry deposition.
■ Transport of chromium from water to the atmosphere is minimal because this
element cannot volatilize from water.
■ Chromium in water is generally in the form of hexavalent chromium or soluble
trivalent chromium complexes depending upon the pH and redox potential of the
water.
■ In soil or sediment, chromium is generally present as insoluble oxide and has
limited mobility. Sediments are a repository for this element in aquatic, estuarine,
or marine systems.
■ The fate of any dissolved chromium depends on the redox potential and the pH of
the soil or sediment. Soluble trivalent chromium and hexavalent chromium are
mobile in soils, although they exist as a small percentage of total chromium in soil.
-■ It is unlikely that all chromium in soil or sediment would be hexavalent chromium
because it is a highly oxidizing chemical species which is usually reduced to
trivalent chromium by soil organic matter.
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Copper
The fate and transport of copper has been reviewed by several authors (ATSDR, 1990;
Bodek et al. 1988; and USEPA, 1979). The following briefly summarizes the factors most
relevant to the site and screening level risk assessment.
■ Copper exists predominantly in the +2 valence state under environmental
conditions, although the + 1 valence state is also possible under specific conditions.
This element is strongly sorbed by hydrous ions and manganese oxides, clays, and
organic matter.
■ In water, copper can exist in the dissolved state, colloidal state, or associated with
suspended solids. The fractional partitioning between these fractions is dependent
upon their relative concentrations, and the geochemical conditions of the
environment.
■ Copper binding to soils is correlated with pH, cation exchange capacity, organic
content, total organic carbon, iron oxides, and carbonates. The relative partitioning
between these phases is measured by selective extraction techniques.
• In sediment, copper tends to bind with organic matter and iron oxides and
carbonates. Under anaerobic sediment conditions, Cu(+2) commonly forms
insoluble sulfide complexes which have reduced bioavailability.
Mercury
The fate and transport of mercury has been reviewed by several authors (ATSDR, 1997c;
Bodek et al. 1988; and USEPA, 1979). The following briefly summarizes the factors most
relevant to the Site and screening level risk assessment.
■ Mercury can exist in three valence states under environmental conditions (0, + 1,
and +2), with the +2 valence state predominant in aquatic systems.
■ Elemental mercury can exist in the vapor state, with air representing a transport
mechanism away from the source area. The significance of this transport
mechanism is related to the source type, amount of atmospheric deposition, and
other environmental factors.
■ In soils and surface waters, mercury may exist as a variety of complex ions
(e.g., chloride and hydroxide) that have varying water solubilities. The specific
mercury complex in the environment depends on such factors as redox potential
and pH. Inorganic mercury may be methylated by microorganisms in soils or
water. In surface waters, the most common complex is elemental mercury which
partitions to particulates in the water column and is transported to sediments.
Sediments may act as significant repositories for inorganic mercury since it is not
readily desorbed from particulates.
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■ Leaching from soils is likely to be an insignificant process, since mercury strongly
adsorbs to organic matter and may also exist as insoluble precipitates. Surface
runoff, however, could be a mechanism for the transport of mercury from soils to
water.
■ The mobilization of mercury compounds from particulates occurs via chemical or
biological reduction to elemental mercury and bioconversion to more volatile
complexes.
■ Inorganic mercury compounds in aquatic systems are readily converted to
organomercury by microbial action (Berlin, 1979), with organomercury compounds
being more toxic than inorganic mercury compounds. The methylmercury
derivative is water soluble and mobile. Biota bioconcentrate mercury compounds
such as methylmercury, which can be further biomagnified through food chains
(Wren, 1986; ATSDR, 1992).
Nickel
The fate and transport of nickel has been reviewed by several authors (ATSDR, 1997d;
Bodek et al. 1988; and USEPA, 1979). The following briefly summarizes the factors most
relevant to the Site and screening level risk assessment.
■ Nickel is a naturally occurring element that exists under environmental conditions
predominantly in the +2 valence state. It readily forms complexes with inorganic
ligands (predominantly hydroxide, sulfate, and carbonate) and organic ligands in
aquatic systems.
■ Typical sorbents for nickel in the environment include iron and manganese oxides,
clay minerals, and organic matter. Nickel can form a sulfide derivative under
reduced conditions with sulfur present, which significantly reduces the
bioavailabilty of this element.
■ Soil and sediment are the primary repository for this element, but mobilization may
occur depending on geochemical conditions.
■ The speciation and physicochemical form of nickel is important in considering its
environmental behavior as well as its bioavailability to organisms. Nickel bound in
mineral lattices tends to be unavailable and is unlikely to have ecological
significance.
Zinc
The fate and transport of zinc has been reviewed by several authors (Bodek et al. 1988;
and USEPA, 1979). The following briefly summarizes the factors most relevant to the
Site and screening level risk assessment.
■ In the environment, zinc occurs predominantly in the +2 oxidation state, and occurs
naturally as the sulfide, carbonate, silicate, and oxide derivative. The solubility of
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zinc in water is strongly dependent upon pH, redox potential, temperature, and the
presence of ligands.
■ Zinc readily co-precipitates with iron and manganese oxides, which reduces the
bioavailability of the zinc in the environment.
■ Typical sorbents for zinc in the environment include iron and manganese oxides,
clay minerals, and organic matter. Zinc can form a sulfide precipitate that
significantly reduces the bioavailabilty of this element.
4.3 Ecological Exposure Analysis
4.3.1 Assessment and Measurement Endpoint Species Selection
USEPA guidance states "Assessment endpoints are explicit expressions of the actual
environmental value that is to be protected" (USEPA, 1998). In most cases, assessment
endpoints represent the plant and animal communities and populations, associated
habitats and any sensitive environments that compose the ecosystem(s) associated with
a site. The objective of a screening ecological risk assessment is to estimate whether past
and or present site-related activities pose a potential for unacceptable risk to ecological
assessment endpoints .
For screening ecological risk assessments, actual measurement of impacts to whole
site-specific animal communities and populations and any associated habitats is
difficult. The difficulty is in part due to the complex interactions both within and
between the animal communities and populations that compose an ecosystem and the
likely absence of community or population based toxicological data for the site-specific
assessment endpoints. As such, measurement endpoints are chosen as surrogates to
represent the assessment endpoints. Measurement endpoints are usually species that
are known or expected to exist in the local ecosystem for which toxicological data are
available or can be derived. Measurement endpoint species are chosen based partially
on the structural characteristics and the different habitat types of the ecosystem. In
designating measurement endpoints, consideration must also be given to those species
that would be exposed to the different source area(s) of a site as a part of normal
activities. For screening ecological risk assessments, USEPA guidance (USEPA, 1998)
requires that species chosen as measurement endpoints have a home range preferably
smaller than the size of any source area. This maximizes the amount of contact that a
measurement endpoint has with the COPCs in order not to underestimate exposure.
Any potential adverse effects on the assessment endpoints can be inferred from
information related to the health status of the measurement endpoint species. In
estimating the extent of any potential adverse effects on measurement endpoints, it is
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important to focus on those effects which have the greatest effect on the health status of
the measurement endpoints. Therefore, it is important to focus on those indicators that
best represent the general health status of the measurement endpoints. The health
status of a measurement endpoint is therefore defined by either the survival rate
represented by mortality or by the reproductive rate of each species.
The measurement endpoint species selected for this screening ecological risk assessment
are ecological receptors that are characteristic inhabitants of the ecosystem located at the
site and who would be naturally exposed to the source areas. Consideration was given
to the size of the home range of each of the measurement endpoints as per USEP A
guidance (USEPA, 1998). The measurements endpoints for the screening ecological risk
assessment were specifically chosen to represent the higher trophic levels of the source
area ecosystems in an effort to address both the direct toxicological and the
bioaccumulative and biomagnifying properties of the COPCs. The measurement
endpoint species selected for the screening ecological risk assessment at both Welch
Creek and adjacent wetlands and Landfill No. 1 and its adjacent wetlands are as
follows:
■ A piscivorous avian species represented by the belted kingfisher (Ceryle a/cyan)
■ A piscivorous terrestrial species represented by the mink (Mustela vis on)
■ An insectivorous and herbivorous avian species represented by the wood duck
(A ix sponsa)
Measurement endpoint species were chosen to conservatively estimate the effects to the
higher trophic levels of the different biotic communities that compose the ecosystem of
Welch Creek and the adjacent wetlands. The belted kingfisher was chosen because as
part of its diet, it could ingest the surface water of Welch Creek and consume fish and
aquatic macroinvertebrates that may have bioaccumulated some of the site-related
COPCs. Likewise, the mink could be exposed to the COPCs through direct ingestion of
Welch Creek surface water and sediment and as part of its diet, fish and aquatic
macroinvertebrates. The mink was also chosen because of its potential sensitivity to the
adverse effects of the P AHs. The wood duck is a species of local interest that is
potentially exposed to site-related CO PCs through ingestion of the surface water and
sediment/soil of Welch Creek and the adjacent wetlands and fish, aquatic plants, and
insects/macroinvertebrates as part of its diet.
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4.3.2 Exposure Parameters
The preliminary exposure evaluation focuses on defining the exposure assumptions
associated with the measurement endpoint species at the RI/FS focus areas. For
completed pathways, the preliminary exposure evaluation involves the selection of
conservative exposure parameters for use in calculating a daily exposure dose for the
selected endpoint species. In the absence of adequate site-specific information or
literature values, conservative assumptions were used in the preliminary exposure
estimate. The use of conservative exposure parameters follows USEPA guidance for
Ecological Risk Assessment (USEPA, 1997) and is intended to prevent the under
estimation of exposure of measurement endpoints to site-related COPCs. Calculation of
measurement endpoint exposure using these conservative exposure parameters tends to
overestimate the actual exposure to the COPCs by the measurement endpoints.
Exposure parameters used in the derivation of the exposure estimate include
bioavailability of constituents, bioaccumulation factors (BAF), endpoint species body
weight, food and water ingestion rates, and area-use factors.
Exposure of the measurement endpoint species to CO PCs in environmental media
associated with Welch Creek and the adjacent wetlands was estimated using a food-web
model. The food-web model estimates the exposure of the endpoint species to the
COPCs through their diet. The direct toxicity characteristics of the COPCs and their
bioaccumulative properties were accounted for by incorporating the COPC
concentrations in various environmental media and key food species of each endpoint
species in the food-web model.
The model for estimation of exposures will be the same for both the Welch Creek and
Landfill No. 1 source areas. Computation of the Landfill No. 1 exposures will be
estimated following collection of data from the RI. The general structure of the model to
estimate daily exposure dose of a given constituent by a endpoint species is as follows:
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where:
IRingestion
!Rh
C
M,
A,
FR
BW
Species-specific total rate of COPC intake by
ingestion (mg/kg-day dry weight)
Fraction of year that species occurs in the geographic
region of habitat h (unitless)
Species-specific rate of COPC intake by ingestion
(mg/kg-day dry weight)
Concentration of the COPC in environmental
medium i (mg/kg dry weight for solids, mg/L for
water)
Rate of ingestion of environmental medium i
(kg/ day dry weight for solids, L/ day for water)
Relative gastrointestinal absorption efficiency for the
COPC in medium i (proportion)
Proportion of Welch Creek and adjacent wetlands
area relative to receptor foraging range (unitless)
Body weight of measurement endpoint species (kg)
As required by USEPA guidance for conducting screening ecological risk evaluations
(USEPA, 1997), selected exposure variables in the food web model were held constant
for all endpoint species. Specifically, those variables address issues of time and area use
factors and gastrointestinal absorption efficiency. The following narrative presents a
description of these exposure variables and the conservative nature of the input value.
■ Time use factors (Th in the equation) are included to account for migratory species
that do not occur in the geographic region.of a site on a permanent, year-round
basis. In this screening ecological risk assessment, endpoint species were assumed
to be year-round inhabitants of Welch Creek and the adjacent wetlands. The
conservative time use factor of 1 was used for all endpoint species.
■ An area use factor (FR in the equation) is incorporated into the food-web model to
account for differences between the area of the site and the foraging range of a
receptor. Fractional area use factors (i.e., values less than 1) are applied for species
with foraging ranges larger than the size of the site. Area use factors can be applied
for a species that is migratory, and that forages over a range larger than the site
during its period of residency in the geographic region of the site. Measurement
endpoint species were assumed to forage totally within the area of Welch Creek
and the adjacent wetlands resulting in an area use factor of 1.
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■ The relative gastrointestinal absorption efficiency (A; in the equation) is the
measure of the bioavailability of a COPC to an endpoint species. An absorption
efficiency factor of 1 was used in the food-web model to account for the
conservative estimation that the total ingested amount of each COPC in each
environmental medium and food species was absorbed by the endpoint species.
In addition to exposure to COPCs in an affected environmental medium (sediments and
surface water), the food-web model includes consideration of COPCs ingested in the
different foodstuffs and forage materials of the endpoint species. The percent
composition of diet for each endpoint species was taken from USEPA Wildlife Exposure
Factors Handbook (USEPA, 1993). These species-specific values were used to calculate
the total amount of each foodstuff that each endpoint species ingested each day. The
species-specific dietary exposure parameters, along with the body weight and water
ingestion rate, are presented in Table 4-3.
4.3.3 Media Exposure Point Concentrations
Media exposure point concentrations are provided for the Welch Creek source area.
Following USEPA guidance (USEPA, 1997), exposure point concentrations for the
screening ecological risk assessment represent the maximum observed concentrations in
environmental media (sediment, soils, and surface water) and biological tissues (fish
and invertebrate tissues). In the case of aquatic plants, where direct analytical
information was not available, reasonable maximum concentrations were estimated as
described below. The use of maximum observed concentrations is likely to overestimate
the actual exposure of the measurement endpoints to the CO PCs in the various
environmental media. USEPA guidance (USEPA, 1997) calls for the use of maximum
observed concentrations in screening ecological risk assessments to ensure that
exposure of measurement endpoint species is overly conservative and not
underestimated.
As discussed previously, the limited investigations previously conducted at Landfill
No. 1 did not result in data of sufficient quality for use in subsequent risk
characterizations. A framework for the screening ecological risk assessment of the
Landfill No. 1 with respect to surrogate receptors and screening TRVs has been
provided in this document. The completion of the screening ecological risk assessment
for Landfill No. 1 will be documented in an addendum following identification of
area-specific ecological COPCs in the initial phases of the field work in the RI/FS. As a
result, the remainder of this screening ecological risk assessment will focus on Welch
Creek and its adjacent wetlands.
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Environmental Media
Maximum observed COPC concentrations in sediment and surface water
concentrations were taken from the voluntary investigation of the lower Welch
Creek surface water and sediment conducted by Weyerhaeuser in late 1995.
Details of the 1995 Welch Creek Study were presented in Technical
Memorandum (RMT, 1998a).
With the exception of dioxins/furans, Table 4-4 presents the maximum
observed concentration of organic and inorganic ecological COPCs for Welch
Creek and its adjacent wetlands. Table 4-4a presents the sample location
corresponding to the maximum observed constituent concentration presented
in Table 4-4. Maximum observed COPC concentrations in sediment samples
were taken from surficial sediment samples representing the sediment zone
available to endpoint species.
For chlorinated dioxins/furans, observed concentrations were converted to a
toxic equivalent concentrations (TEQ) of 2,3,7,8-TCDD using International
Toxicity Equivalence Factor (TEF) methodology from USEPA (USEPA, 1989) as
published in USEPA Region IV Supplemental Guidance (USEPA, 1996). TEFs
are presented in Table 4-5. The 2,3,7,8-TCDD TEQ presented in Table 4-4
represents the toxic equivalency of dioxin and furan congeners present at
surface water and sediment locations with the maximum observed·
2,3,7,8-TCDD concentration. Additional details with respect to TEQ
calculations are presented in Appendix E.
Whole Small Fish and Invertebrate Tissue Samples
The Compilation of Existing Data Technical Memorandum (RMT, 1998a) presented
historical invertebrate and fish tissues collected in Welch Creek. Invertebrate
and fish tissues collected from Welch Creek as a component of the 1995 studies
were analyzed for 2,3,7,8-TCDD/2,3,7,8-TCDF, total mercury, lipid, moisture,
and total dioxin and furan isomers.
Table 4-4 presents the maximum observed concentration of mercury in Welch
Creek invertebrate and fish tissues. Table 4-4a presents the sample designation
corresponding to the maximum observed constituent concentration presented
in Table 4-4. As with sediment and surface water, detected concentrations of
dioxin/furan isomers were converted to 2,3,7,8-TCDD TEQ using TEFs
methodology described previously. Additional details with respect to TEQ
calculations are presented in Appendix E .
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Aquatic Plants
For the purpose of the screening ecological risk assessment, concentrations of
COPCs taken up by plants from sediments in Welch Creek and adjacent
wetlands were estimated using procedures detailed in Appendix F. Predicted
COPC concentrations in aquatic plant tissues are presented in Table 4-4.
Additional technical discussion and plant concentration calculations are
provided in Appendix F.
4.3.4 Estimated Daily Exposure Dose
The conservative exposure variables were integrated with exposure point
concentrations by media into the food-web model to arrive at estimates of the total daily
exposure doses of the endpoint species (i.e., kingfisher, mink, and wood duck). The
estimated daily exposure doses of individual COPCs for each of the three selected
endpoint specie_s evaluated in the screening ~cological risk characterization are
presented on Tables 4-6 through 4-8. Additional details with respect to the exposure
parameter assumptions and estimated daily exposure dose calculations for each
screening endpoint species are presented in Appendix G.
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Table 4-1
Preliminary Toxicity Reference Values for
Screening Ecological Risk Assessment Endpoint Species
,p-\',V• ,, ;,., • •• , .. ;.. ,~.,:., -. :r<>~:T~Yl,::~:~i:.:2J ,·.·,,n;,/"".; •. -1-s,· -:·"_Y _,·1r.:.-;,.;.,.,1"',-'\.f'"O-· ,:,;, .. -•,, · ·W-' --~.;..,. --~ ·-~ · ; .• •o/· '"•'~ .-.. :":;,~CONSTITUENT,::;, .... _,*:,c.'!,_•·J.'i0••1,-l-,. i";:,a,-,ti>~~~ ... 'i•·;~BASIS, .,,., i-.,,1.-,.,,,.:--..,.,s:/ ,"t ,\, :,..:,~:.' 'i• :~i}\~)z·/_·;~itf.:.~t;:·;~~;r -i;::"::$~~kg~~~i>_:t•~,;; fJfrJf:ttJ~;&,)!j(~1:~}j;~-J"it:{fttf }r3;~":ttf ~: \•:;,~-.,::· .t;:,\?(:):~:
Belted Kingfisher
2,3,7,8-TCDD 0.000014 Nosek et al., 1992 per Sample et al., 1996
Chromium VI 1.0 Haseltine et al., unpublished data per
Sample et al., 1996
Mercury 0.0064 Heinz et al., 1979 per Sample et al., 1996
Mink
2,3,7,8-TCDD 0.000001 Murray et al., 1979 per Sample et al., 1996
Arodor1242 0.069 Bleavins et al., 1980 per Sample et al., 1996
Arodor 1260 0.14 Aulerich and Ringer, 1977 per Sample et al., 1996
Phenanthrene 1.28(2) Sax and Lewis, 1989
Pyrene 1.2(2) Yoshikawa et al., 1985
Chromium VI 3.28 MacKenzie et al., 1958 per Sample et al., 1996
Copper 11.7 Aulerich et al., 1982 per Sample et al., 1996
Mercury 0.015 Wobeser et al., 1976 per Sample et al., 1996
Nickel 40 Ambrose et al., 1976 per Sample et al., 1996
Zinc 160 Schlicker and Cox, 1968 per Sample et al., 1996
Wood Duck
2,3,7,8-TCDD 0.000014 Nosek et al., 1992 per Sample et al., 1996
Arodor 1242 0.41 McLane and Hughes, 1980 per Sample et al., 1996
Arodor 1260 1.34(2) Custer and Heinz, 1980
Phenanthrene 1.28(2) Sax and Lewis, 1989
Pyrene 1.2(2) Yoshikawa et al., 1985
Chromium VI 1.0 Haseltine et al., unpublished data per
Sample et al., 1996
Copper 47 Mehring et al., 1960 per Sample et al., 1996
Mercury 0.0064 Heinz, 1979 per Sample et al., 1996
Nickel 77.4 Cain and Pafford, 1981 per Sample et al., 1996
Zinc 14.5 Stahl et al., 1990 per Sample et al., 1996
Ol Preliminary TRVs were obtained from Sample et al., (1996), unless otherwise noted.
<21 Derivation of this preliminary TRV is summarized in Section 4.1.3.
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Table 4-2
Environmental Fate and Transport Parameters for Screening Ecological COPCsm
-·1,,t, \: ,·;;::-~ : .. ,.: ·e: '.,if..,f+ 'l """'\l/w ATER,,., :if'' ~,fMo ii1ctiiAR.: i.';; ~~ ~~ -:~.VAPOif:tr~i-~ ~
1'HENRY;SJ:AW:~~; .~ ... : x.:~: : ''-:;,,;.r..: 7~ .:. ; '~:'JV'.·{: :.:'¾,-.Je-:.dh•:1;_.:'.~hi1:"f:ti·~<' ;. :"'3~· >-~ .. :,._ ~f~·:.·::.:~ ~:~~-wiiiGiii':li:\i ~'.f~REssuili' ~i, J~,f~ ·' ,:~»£-., •,~s·,.F·,t,i,'tf :"~i;;~1"i'll"f~~; ,, ·. __ , •GONSTITUEN ')iJSOl.:UBILIT,Y ·y::; ·• €ONSTANT's ,, ~::1T?~~{i~~tt ,-tt?:7~i;~ ~; Ii~t!mWJ.>~~r1·~;:
'"I:. '>Ii'·+--· -r. ,-'~-s._,,._">-tt:i; .. ~~~~gt{r1 1::.r~~tp4J~~~~~:~:, ~ l~:,:i ~;;ii~,JJ :;, --~--;<gtmdle)J.it:.d'"< "':l.--~~-~ -~-· -· -~• .... ,
2,3,7,8-TCDD 0.000019(2) 322(2) 7.4E-10(2) l.0lE-08(2) 6.3E+06<2>
Aroclor 1242 0.24(4) 268(4) 1.3E-03 1.98E-03 l.3E+04
Aroclor 1260 0.003(4) 372<4> 4.05E-05 7.4E-01 l.4E+07
Phenanthrene 0.816 178 6.8E-04<5> 3.93E-05<5> 2.88E+04<5>
Pyrene 0.16 202 2.SE-06<5> 5.lE-06<5> 1.51E+05<5>
Chromium VI (6) 52 (7) NIA NIA
Copper (6) 64 (7) NIA NIA
Mercury 0.056 (9) 200 2.0E-03 <9> l.14E-02 NIA
Nickel (6) 59 (7) NIA NIA
Zinc (6) 65 (7) NIA NIA
OJ Data from USEPA (1992) unless otherwise noted.
(2) Data from ATSDR (1997a).
(JI Kd is matrix specific for organic constituents.
14) Data from Erickson (1997).
(SJ Data from Mabey (1982).
(61 Varies with ligand or complex. Metallic forms are generally insoluble or sparingly soluble in water.
(7) Measurable vapor pressure only at elevated temperatures (>200°C).
(8) Inorganic Kd values from Bases et al. (1984).
191 Data from ATSDR (1997c) for elemental mercury.
•
ti~~~t~{rtl/!
(3)
(3)
(3)
(3)
(3)
850(8)
35(8)
10(8)
150(8)
40(8)
October 1998
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•
•
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Table 4-3
Species-Specific Exposure Parameters for Screening Ecological Risk Assessment Endpoint Speciesnl
Body weight (kg) 1.4 0.215 0.680
Water Ingestion Rate (L/day) 0.15 0.016 0.046
Total Dietary Intake Rate (kg/day) 0.308 0.376 0.373
Sediment Ingestion Rate 8 0.025 NA 11 0.041
Fish Ingestion Rate 82 0.252 75 0.282 5 0.018
Invertebrate Ingestion Rate 10 0.031 25 0.094 14 0.052
Aquatic Plant Ingestion Rate NA NA 70 0.262
<1> Exposure factors were taken from the Wildlife Exposure Factors Handbook (USEPA, 1993), unless otherwise noted.
<2> Percent composition of Wood Duck diet based on information contained in Bellrose, 1980, Terres, 1991, and.Beyer, 1994.
NA Not applicable; media or forage material not considered a significant component of endpoint species diet.
RMT, Inc.
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4-22 Weyerhaeuser Company
October 1998
• • •
Table 4-4
Welch Creek Screening Exposure Point Concentrations by Mediam
\'!,,,'),,f:,,S" ·~. W ''-•' • c.:..'c>icXJ""'·~,)CC~~•;.• . >' , • •~ ,., . '.;,, CCJ _..,.,-,..,. --1•-·-·,.s,.--....,-.,~,,,.~,-,,., ;:··,_.,-,.,_i , ........... ,.-...-.-,...,·:·>-)f.!.\i-"'.;'., _,,.,.,,.._ • .;;,.. _. ·1 ·::,, ::; ..,,t,,;; •--·r·,,,.-,:--.... _q ,._.,. ,,. • .,,,_. ,a·
"''if.'r 2,1y;>,l i L99t\q<?!:1') -"~:i~/.:ii:t~ -~I h:1}.~~-'3J~-~Nl;:l·r .... ~ ,'rSURFACEWATER>I• "c\SMALL,WHOtE·.:~; !ii'; 11 ,,; ~.91Li:\IIq,.,.;;,'.{'. '··· · '.JAQUATIC'-•• .,, . . . ,,, GONSTITUENT'" ·· ' · · ' · .. (. ~ l ·· •·-"f ;),(~;~~~ft}~ :r:-~ .. ;':_~,:.'FiSHi1:·tt~]:;~~ "'-~•t.: ··--, -~-· ····•-· ., .-.,·,.._y;, '~,. ;:h:;-,,· -· .:t':.i 'tF-.J> :ft,,1,J/~·-'4?-m g ,-"-"~>!·":'.,; iflN~RTI:_B,SATliS, i' :,;,•(i" ''PLANTS"'!,~•.· , ·_;d..._: ,· ':<,~.;:2£-,.~·:•ii, "'•'._!:-'''":';~_;_ • .:.'f'.b-: • ;,°:e~,. "'.. '.~ ... ....,_tfl, ._. ~);~7 ;i•:_:j}·::v~¥~gy{~~~ ~.~~;J Jtt'(ihg(k'g)"""-:.::~~fj-tJ. ~'{} ·:·~JT~Si;-~t:1~),t •~!' ~ \ __ • -.. ,. • .1~ ·c..,,,."!:f .. p~~"'~--. ·;il~,v:. 1d.1{~-~'" '1,. 'JJ~,._,,.,,v,· .,-,n,:rt-'..' .•"t~'P.G.-. ,-,.,_·,;'V;:,;.1;'.t.3;_ "-~~ ·' ·' .~J ~-: ,«----:t!.-.'. :;;p~-!" -. ·9_· ,.{ et"'.;;.:. :!a~..;,,,.•,;',-'~ ~< 1..,. •" };;,_.,:l,,'"f• c:;_,
Welch Creek
2,3,7,8-TCDD TEQC21 4.58E-03 1.56E-09 l.04E-04 2.28E-04 l.70E-03
Phenanthrene 0.34 NC NA NA 2.89E-02
Pyrene 0.56 NC NA NA 4.76E-02
Mercury 11.1 NC 0.08 0.04 10
Chromium 1320 NC NA NA 9.9
Copper 89 NC NA NA 36
Nickel 63.8 NC NA NA 3.8
Zinc 399 NC NA NA 600
Adjacent Wetlands
2,3,7,8-TCDD TEQC2l 4.13E-03 9.35E-07 NA NA l.4E-03
Aroclor 1242 0.24 NC NA NA 6.0E-02
Aroclor 1260 0.2 NC NA NA 1.2E-03
Mercury 5.6 0.00083 NA NA 5
Chromium 333 0.06 NA NA 2.5
Copper 82.7 NC NA NA 33
Nickel 28.9 NC NA NA 1.7
Zinc 207 NC NA NA 310
((ll The exposure point concentrations used in the Screening Ecological Risk Assessment represent the maximum observed concentration for each parameter.
Refer to Table 4-4a for corresponding sample locations.
(2) 2,3,7,8-TCDD TEQ was calculated using International TEFs published in Region IV Supplemental Guidance to RAGS for location with maximum
observed 2,3,7,8 TCDD concentration.
(Jl Aquatic plant concentration derived for vegetative portion of plant based on uptake from sediments. Calculated from maximum sediment concentration.
NA Analysis for this constituent was not conducted in this environmental medium or food source.
NC This constituent is not a COPC in this environmental medium at this location. All mg/kg concentrations expressed on a dry weight basis.
October 1998
G:\ wren \5\.~ llllll 2C.VOC
• • •
Table 4-4a
Sample Locations for Welch Creek Screening Exposure Point Concentrations by Media
&·it~1'~~{1,'tOCA TioNti:~,~~~~ ,.);'(,;"J•"'~ji.l}< ,-,.,,., ."""4~~"'·"-·:.;, -l r·c -~ ,c,c,-._,,;,-. ,-__,.~""-._,, ''""··• --~-~~ P+,'.'.'-' ;-•, .,,. ·•,:"'°~-•.,;.t~.-:;..,...,_,, • ..,t.-;,·• W -~.rtt~tAQUATiG:2;.~~-t0:.~: l'7'.,, ~SEDIMENT<'·. ·;· · · ;,·Y•;SlJi!fAqE;W_AT!:R'.., ,;:1 ~"""''·lSMALbWHOLE,\;,<'. ~ -·~ _' . ""---,. .-,,,... ..... -, -·--"-,~-< .... -,~-if'3_ ... '.:!;;:t-1"'~-· :}d':-}? '.::;;">':,,-_., f.c'-=;i\ ],.,,'-~bf,· '"~S,iji::;t'~,t~n•';\:,J .• 0rtt.'.-fr"f.~:~:1siSff).,7.ii;"~•:\f~ t~~INY-EltfEBRA TESJ}-~-: •·:t:..'.c/,,:;coNsTITUENT;ly'~"'' 1;(1¥:-.t~{~,~f~}1t.~:.:'t'i: cs~· s. ,,.._._.~,5i·!;,,_.-.~"-•"~•---,.• ";f<.c..,,"'C•~·-.R. -~· )C~. ~-.:.:: .)t';~~ ·-·tt:·.lt ~: -~-f~J;'t.~· ;,-1·--:.•·-~• '! ,:tt,.,....__,., l,';;,._ j,t_~ ~!.'Li ••• __ ,...,. 11 -·-7 ... -:-,,,_~:-.,~~---•:f,o.'.,.·
Welch Creek
2,3,7,8-TCDD TEQ(ll MT0SLB20-MP SWMT08-70-M MTS-1-LL(F)-TA MTS-1-SS-TA
Phenanthrene MT04MP-70-00S NC NA NA
Pyrene MT0SMP-70-00S NC NA NA
Mercury MTlOMP-60-0S NC MTS-1-LL(F)-TA MTS-1-LL(l)-TA
Chromium MT08MP-70-00S NC NA NA
Copper MTlOMP-60-0S NC NA NA
Nickel MTlOMP-60-0S NC NA NA
Zinc MT04MP-40-0S NC NA NA
Adjacent Wetlands
2,3,7,8-TCDD TEQ(ll MT07-WL SWMT07-.WL NA NA
Aroclor 1242 MT07-WL NC NA NA
Aroclor 1260 MT07-WL NC NA NA
Mercury MT07-WL SWMT07-WL NA NA
Chromium MT07-WL SWMT07-WL NA NA
Copper MT07-WL NC NA NA
Nickel MT07-WL NC NA NA
Zinc MT04-WL NC NA NA
<O 2,3,7,8-TCDD TEQ was calculated using International TEFs published in Region IV Supplemental Guidance to RAGS for location with maximum
observed 2,3,7,8 TCDD concentration.
NA Analysis for this constituent was not conducted in this environmental medium or food source.
NC This constituent is not a COPC in this environmental medium at this location. All mg/kg concentrations expressed on a dry weight basis.
October 1998
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RMT, Inc.
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Table 4-5
International Toxicity Equivalency Factors
1;ii/:,~ -?f~~;;ztrii¢9MJ,O.P~P/b?t,1!:r~~:i~:}:;J1/~ }tJ.;2::_;,f 1\:~T~.:.:..?\~1ff: ~
Dioxins
2,3,7,8-TCDD 1
2,3,7,8-PeCDD 0.5
2,3,7,8-HxCDD 0.1
2,3,7,8-HpCDD 0.01
OCDD 0.001
OtherCDDs 0
Furans
7,8-TCDF 0.1
1,2,3,7,8-PeCDF 0.05
2,3,4,7,8-PeCDF 0.5
2,3,7,8-HxCDF 0.1
2,3,7,8-HpCDF 0.01
OCDF 0.001
OtherCDFs 0
TEFs published in Region IV Supplemental Guidance to RAGs 1996
4-25 Weyerhaeuser Company
October 1998
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G:\ WPCVL \S\51001 ZG.DOC
Welch Creek
2,3,7,8-TCDD TEQ(l) 2.36E-04
Mercury l.22E-01
Adjacent Wetlands
2,3,7,8-TCDD TEQ(l) 6.96E-08
Mercury 6.18E-05
Chromium 4.47E-03
<1> 2,3,7,S-TCDD Toxicity Equivalent Concentration was calculated using TEFs
published in Region IV Supplemental Guidance to RAGS.
4-26 Weyerhaeuser Company
October 1998
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RMT, Inc.
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Table 4-7
Estimated Daily Exposure Dose of COPCs for Mink
,.~,.,:z-·-·!'ii••--',-'--'','."''\•,,_,.,_,,.., .. ~., ' ··,·•'('·· . '•·TOT AC.ESTIMATED ";: :f~'~-' r.:~~;1.,,:,3;:fiOCA TION/,'t,:;~;~~ .. :~« · .. r; :;·_; ~,,..:i~,.tr;,.,'i;-''-·,..~·--... ~--. .-....,f;;_..,1,•tji,.·ref.l~J~~ • -I' ,, . «-·. ~ ,,~,., • ~ -~·-•~ ·, :'t""',il, ;,,,, \f,,,,, •. .,, ,•,CONSTITUENTc, .. ~•: ·"!'.'".:,•·•·· ;f;:DAILY:EXPOSURE-"/:' t~:~~}z\:i~:~·K.~l-~~httff~;?.~t--i-X;~i:,:i~::~a~.r ~-,._;-i,,. '''{ --: • ·-·~-i ·.·•1 ;1J ,-·,t' · :1,.,; 1t·, , ll~!_Y:.(_~~g~d~y);-y1: ;::.::t;:~
Welch Creek
2,3,7,8-TCDD TEQ0> l.0SE-04
Phenanthrene 6.02E-03
Pyrene 9.92E-03
Mercury 2.12E-0l
Chromium 2.34E+0l
Copper l.58E+00
Nickel l.13E+00
Zinc 7.07E+00
Adjacent Wetlands
2,3,7,8-TCDD TEQCI) 7.33E-05
Aroclor 1242 4.25E-03
Aroclor 1260 3.54E-03
Mercury 9.93E-02
Chromium 5.91E+00
Copper l.46E+00
Nickel 5.12E-0l
Zinc 3.67E+00
111 2,3,7,8-TCDD Toxicity Equivalent Concentration was calculated using TEFs
published in Region IV Supplemental Guidance to RAGS .
4-27 Weyerhaeuser Company
October 1998
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RMT, Inc.
G:\ WPGVL \5\51i/012G.DOC
Table 4-8
Estimated Daily Exposure Dose of COPCs
for Wood Duck
•-1,.r"~;•c,h""I,:(:~.,• •••· •-• ,' ·_ •. •~,;,J.,•.,•,-•;-•,:,;~:".I" ""if · :'toi'Xi· isi:11.!A TED t . :,.: . .:)f'i"\,}i;1t:/t.-:", ... •LOCATION/, ~1;-.-.:1t',_.:t~: -1, ,'.;;\!" t··J'-:::...-. •... ,;~-' . " • ,, -_,' ,;,-~::-_.~;:-. i>}·.1.,,,,1. ·, __ i:.._, •. -:·., . '". ·•·-.• ,-• "'4")' ,::;'::lit""' ,., .• 1,. ,, CONSTITUENT.,we,.,,~t,,·,·• :£· · ·, ';;"P1I.L. Y-li~9~!.JREi.':, Z~ .. ·--)-v~'f ~;~ n·4;;~ -._,1f".,; ~'. ·i«,:f;:j,_'_':.. .... ·';fr-:• i~,;r~~--"·it'("'' g/lc -d·--);;ez:_,:,.1•·:t!t ~1-· ·a~ , ,.,.e:. ,._ ~-. 11·,•tr~ '1~~ ·)A;g ;""·tlli•·· ti<,. :ct'."~--µ ¥.<e:ft,.:-:·t·~-~ g-_ ~Y.,;:_•,:}"'·~;1. ,,,__\<, •, . .10\l, ,, "'·-" i,._C:. 'A'-' ,,1/.\._ " ~<..~•• "'•--!~ ,o
Welch Creek
2,3,7,8-TCDD TEQ(l) 9.52E-04
Phenanthrene 3.17E-02
Pyrene 5.21E-02
Mercury 4.53E+00
Chromium 8.35E+0l
Copper l.92E+0l
Nickel 5.31E+00
Zinc 2.55E+02
Adjacent Wetlands
2,3,7,8-TCDD TEQ(l) 8.0SE-04
Aroclor 1242 3.76£-02
Aroclor 1260. 1.25£-02
Mercury 2.26E+00
Chromium 2.llE+0l
Copper l.77E+0l
Nickel 2.40E+00
Zinc l.32E+02
0) 2,3,7,8-TCDD Toxicity Equivalent Concentration was calculated using TEFs
published in Region IV Supplemental Guidance to RAGS .
4-28 Weyerhae11ser Company
October 1998
• Table B-3
Surficial Sediment Sample Locations Used in Screening Risk Evaluation
MTOlMP-60-00N MT06MP-40-05-10
MT02MP-30-0S MT06MP-40-09N
MT03MP-110-0S MT06MP-40-MP
MT04MP-40-0S MTOSMP-70-00-05
MTOSLB-20-00-05 MTOSMP-70-00S
MTOSLB-20-05-10 MTOSMP-70-05-10
MTOSLB-20-MP MTOSMP-70-MP
MTOSLB-20-N MTOSMP-70-NAT
MTOSMP-50-00S MT09MP-30-0S
MT06MP-40-00-05 MTlOMP-60-0S
MT06MP-40-00S
/:\ WPGVL \5\51001 ZE.DOC Weyerhaeuser Company, Martin County Facility
•
•
potentially pose an unacceptable risk to the mink. Further evaluation to assess
this potential hazard is warranted.
Wood Duck
As presented in Table 5-3, potential risks to the wood duck were estimated for
the Welch Creek COPCs, dioxins, phenanthrene, pyrene, mercury, chromium,
copper, nickel, and zinc. Exposure of the wood duck was limited to ancillary
ingestion of sediment for the PAHs phenanthrene and pyrene. The remaining
COPCs were considered to be ingested by the wood duck as components of
aquatic plants. The dioxins and mercury were considered to be ingested in
surface water and invertebrates. Dioxins, mercury, chromium, and zinc were
the COPCs with a hazard quotient greater than 1.0. The PAHs, phenanthrene
and pyrene and the metals copper, and nickel had a hazard quotient less than
1.0. The dioxins, mercury, chromium, and zinc require further evaluation due
to their potential to pose an unacceptable risk to the wood duel< or other
herbivorous/insectivorous avian species.
The wood duck as an endpoint species for Welch Creek was similarly
considered to be exposed to the adjacent wetlands. Exposure of the wood duck
was evaluated on the basis that exposure to wetlands COPCs occurred through
ingestion of surface water, sediment, and aquatic plants. The wetlands COPCs
with a hazard quotient greater than 1.0 were the dioxins, mercury, chromium,
and zinc. The remaining COPCs; namely, Aroclor-1242, Aroclor-1260, copper,
and nickel, had a hazard quotient less than 1.0 and are not considered to
require further evaluation. The screening risk characterization indicate that
dioxins, mercury, chromium, and zinc are COPCs considered to pose an
unacceptable risk to the wood duck and other herbivorous/insectivorous avian
species. Further evaluation to assess this potential risk is warranted.
5.1.2 Landfill No. 1
As discussed previously, the limited investigations previously conducted at the Landfill
No. 1 did not result in data of sufficient quality for use in risk characterizations. A
framework for the screening ecological risk assessment of the Landfill No. 1 with
respect to surrogate receptors and screening TRVs has been provided in this document.
The completion of the screening ecological risk assessment for Landfill No. 1 will be
documented in an addendum following identification of area-specific ecological COPCs
in the initial phases of the field work in the RI/FS .
RMT, Inc.
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October 1998
,I
■ Assuming constituents present in the surface soil and stream sediment have a significant
tendency to desorb from the soil or dissolve from mineral phases and as a result be
bioavailable is likely to overestimate exposure,
■ The assumption that the constituents designated as a COPC are 100 percent bioavailable
upon ingestion, that is, 100 percent of the amount of the COPC ingested is absorbed by the
gastrointestinal, tract of the endpoint species is likely to overestimate exposure,
■ Using the maximum detected concentrations is likely to overestimate intakes since actual
exposure expressed as mean concentrations more accurately reflect exposure over time,
■ The absence of data for specific dietary components used in the risk evaluation for the
surrogate receptors will tend to underestimate the potential exposure,
■ The assumption that ecological receptors live and forage solely within the source areas of
the site overestimates exposure.
In general, the assumptions of the exposure assessment can result in significant overestimates
of exposure, Therefore, the exposure estimates are likely to be greater than the maximum
exposures that can be reasonably expected to occur, Despite these uncertainties, the screening
ecological risk estimates summarized in Tables 5-1 through 5-3 conform to USEPA guidance,
RMT, Inc,
G:\ WPCVL \5\51CJ012G.DOC
5-6 Weyerhaeuser c;:ompany
October 1998
•
PRIMARY SOURCE
Wastewater Solids in Welch Creek
~I
•
PRIMARY RECEITOR
Fish _________ ....
l
SECONDARY RECEITOR
Fish
' .
f------J I Benthic macroinvertebrates
PRIMARY RECEITOR
SECONDARY SOURCES
Potentially-Affected Surface Water
Potentially-Affected Sediment
►
__ __.
I PRIMARY RECEITOR
I _____ A_q_u_a_ti_c_r_1a_n_ts ___ ...,
Figure 6-1
, ,
ASSESSMENT ENDPOINT
Piscivorous Birds
and Mammals
ASSESSMENT ENDPOINT
Insectivorous and
Herbivorous Birds
•
lllt!l.~ Conceptual Exposure Model for Welch Creek and Adjacent Wetlands
Oct-98
5100.06
Weyerhaeuser Company
Martin County, North Carolina
• • Table G-1
Total Daily Exposure for Kingfisher
Exposure Point Ingestion Rate
Location Constituent Concentration 1
Surface Water Fish Aq. Invertebrates Surface Water Fish Aq. Invertebrates
(mg/L) (mg/kg) (mg/kg) (mg/kg-day) (mg/kg-day) (mg/kg-day)
Welch Creek
2,3,7,8-TCDD TEC2 1.56E-09 1.04E-04 2.28E-04 1.16E-10 1.36E-04 9.97E-05
Mercury NC 0.08 0.04 1.0SE-01 1.75E-02
Wetlands
2,3,7,8-TCDD TEC2 9.35E-07 NA NA 6.96E-08
Mercury 0.00083 NA NA 6.18E-05
Chromium 0.06 NA NA 4.47E-03
1 The exposure point concentrations used in the Screening Ecological Risk Assessment are the maximum detected concentration of each constituent, unless othen-..-ise noted.
2 2,3,7,8-TCDD Toxicity Equivalent Concentration was calculated using TEFs from Region IV Supplemental Guidance to RAGS.
NA Analysis for this constituent was not conducted in this environmental medium or food source.
NC This constituent is not a COPC in this enviromental medium at this location.
IR ,.-,000 = [(fh)(C; • M; •A;• FR/ BW)]
Th= species occupation factor
Ci= constituent concentration in medium I
Mi a rate of ingestion of medium I
Ai = absorption factor
FR = receptor foraging range
BW = receptor body weight
g: \data/hydro\ 5100\ excel\ ecorisk \ intwey .xls
1
See above
See table
1
0.215
unitless
mg/kg or mg/L
kg/ day or L/ day
unitless
unitless
kg
Food (kg/ day)
Fish (kg/ day)
Invertebrate! (kg/ day)
Water (L/day)
0.376
0.282
0.094
0.016
•
Total Exposure
(mg/kg-day)
2.36E-04
1.22E-01
6.96E-08
6.18E-05
4.47E-03
Kingfisher
10/15/98