NCD980840409_19940314_Charles Macon Lagoon & Drum_FRBCERCLA ROD_Conditional Concurrence with the April 1992 ROD Amendment-OCR

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State of r-~ca,. Carolina : Departme,,.,f Environment, Health and Natural Resources
Division of Solid Waste Management
James B. Hunt, Jr., Governor
Jonathan B. Howes, Secretary
William L. Meyer, Director
•.WA
DEHNR
March 14, 1994
Ms. Giezelle Bennett
. Superfund Branch, Waste Management Division
US EPA Region IV
345 Courtland Street
Atlanta, Georgia 30365
RE: Conditional Concurrence with the April 1992 Record of Decision (ROD)-Amendment
Macon/Dockery Site
Cordova, Richmond County
Dear Ms. Bennett:
The North Carolina Superfund Section has received and reviewed the ROD Amendment for the Macon/Dockery Site and concurs with the modifications of the selected remedies subject to the following conditions:
1.
2.
As noted in our letter dated January 25, 1994 on the 60% Remedial Design, to effectively design a groundwater remediation system for the Site, it is essential that the hydrogeologic characterization of the Site continue. The hydrogeologic model developed during the Remedial Investigation is, as it should be, conceptual and highly general in nature. Work during the
Remedial Design phase should continue to add details and refinements to this model.
Our concurrence on this ROD Amendment and the modifications of the selected remedies for the site is based solely on the information contained in the attached ROD Amendment. Should we receive additional information
which significantly affects the conclusions or remedies contained in the ROD and the ROD Amendment, we may modify or withdraw this concurrence with written notice to EPA Region IV.
P.O. Box 27687. Raleigh. North Carolina 27611-7687 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer sax. recycled/ l 0% post-consumer pOper
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Ms, Giezelle Be.t
March 14, 1994 • Page 2
3. Our concurrence on this ROD Amendment in no way binds the State to
concur in future decisions or commits the State to participate, financially or
otherwise, in the cleanup of the Site. The State reserves the right to review,
comment, and make independent assessments of all future work relating to
this Site.
We appreciate the opportunity to comment on this ROD Amendment for the
Macon/Dockery Site and look forward to continuing to work with the EPA to remediate this
Site.
Attachment
Sincerely,
Jack Butler, PE
Environmental Engineering Supervisor
Superfund Section
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· MACON/DOCKERY SITE
RICHMOND COUNTY, NORTH CAROLINA
APRIL 1992 RECORD OF DECISION
AMENDMENT
REGION IV
ATLANTA, GA
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Record of Decision Amendment
Macon/Dockery Site
DECLARATION FOR THE
RECORD OF DECISION AMENDMENT
Fundamental Change to the Selected Remedial Alternative
SITE NAME AND LOCATION
Macon/Dockery Site
Cordova, North Carolina
STATEMENT OF BASIS AND PURPOSE
Februar 1994
This amendment to the decision document presents a fundamental change to
the selected remedial action for the Macon/Dockery Site, in Cordova, North Carolina,
chosen in accordance with CERCLA, as amended by SARA and, to the extent
practicable, the National Contingency Plan. This decision is based on the
administrative record for this Site.
The State of North Carolina concurs on the selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this Site, if not:
addressed by implementing the response action selected in this ROD Amendment,
may ggl;jpfiµ§i:[fg:Present an imminent and substantial endangerment to public health,,
welfare, or the environment.
DESCRIPTION OF THE MODIFIED REMEDY
. The purpose of this Record of Decision Amendment is to i:1r\(\QQO¢!:i}i
m§9if!5~p§QI§t;:modify the remedy, based upon new information incl~dfngreceni:
sampling data and results from the treatability study, so that the selected remedy is
better suited to illBf~~rt~?ifiY~!§rthe particular conditions posed by this Site.
The major components of the selected ffiQQJf!~g:remedy include:
Excavation of contaminated setts fil~!~mi!~in the Lagoon 10 area;
Disposal of the excavated setts ffiA.t~fi~I§ in an approved off-site disposal
facility;
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Record of Decision Amendment Februer 1994
Macon/Dockery Site
Extraction of groundwater across the Site that is contaminated above
performance standards;
On-site treatment of the extracted groundwater via air stripping and ion
exchange; and
Discharge of treated groundwater to on-site infiltration galleries.
STATUTORY DETERMINATIONS
The modified remedy is protective of human health and the environment,
complies with Federal and State requirements that are legally applicable or relevant
and appropriate to the remedial action, and is cost-effective. This remedy utilizes
permanent solutions and alternative treatment technologies to the maximum extent
practicable for this Site, and satisfies the statutory preference for remedies that
employ treatment that reduces toxicity, mobility, or volume as a principal element.
John H. Hankinson, Jr.
Regional Administrator
Date
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Record of Decision Amendment
Macon/Dockery Site Februer 1 994
TABLE OF CONTENTS
SECTION PAGE NUMBER
1 .0 INTRODUCTION
1. 1 Site Name and Location
1.2 Lead and Support Agencies
1. 3 CERCLA Section 117 & NCP Section 300.435
1.4 Original Record of Decision
1.5 Summary of the Circumstances Leading to the
ROD Amendment
1.6 Administrative Record
1. 7 Administrative Record Availability
2.0 REASONS FOR ISSUING THE ROD AMENDMENT
2.1 Description of the Remedy Selected
in the Original ROD
2.2 Summary of Rationale For Changing Remedy
in the Original ROD
2.2.1 Results of the Bioremediation
Treatability Study
2.2.2 Groundwater Performance Standards
Evaluation
2.2.3 Groundwater Bioremediation Pilot
Study
3.0 REMAINING ALTERNATIVES CONSIDERED IN THE ORIGINAL
ROD FOR LAGOON 10
4.0 DESCRIPTION OF THE MODIFIED REMEDY
4. 1 Comparison of the Original Selected Soil
Remedy with the Modified Remedy
4.1.1 Original Soil Remedy's Treatment
Component
4.1.2 Modified Soil Remedy's Treatment
Component
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Record of Decision Amendment Februar 1994
Macon/Dockery Site
TABLE OF CONTENTS
SECTION PAGE NUMBER
4.2 Comparison of the Original Selected Groundwater
Remedy with the Modified Remedy 1 0
4.2.1 Change in Groundwater Standards 10
4.2.2 Other Groundwater Remedy Changes 10
5.0 EVALUATION OF THE MODIFIED REMEDY 11
5. 1 Overall Protection of Human Health
and the Environment
5.2 Compliance with ARARs
5.3 Long-term Effectiveness and Permanence
5.4 Reduction of Toxicity, Mobility, or Volume
5.5 Short-term Effectiveness
5.6 Implementability
5.7 Cost
5.8 State Acceptance
5.9 Community Acceptance
6.0 STATUTORY DETERMINATIONS
6.1 Satisfaction of CERCLA Section 121
7.0 RESPONSIVENESS SUMMARY
APPENDIX A -ORIGINAL RECORD OF DECISION
FIGURE 1 -SITE LOCATION MAP
TABLE 1 -ANALYTICAL RESULTS OF
BIOREMEDIATION STUDY
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Record of Decision Amendment Februar 1994
Mscon/Dockery Site
DECISION SUMMARY
1.0 INTRODUCTION
1.1 SITE NAME AND LOCATION
The Charles Macon Lagoon and Drum Storage Site and the Dockery Site, collectively
referred to as the Macon/Dockery Site, located in Richmond County, North Carolina,
was operated as a waste oil recycling and antifreeze manufacturing facility from 1979
to 1982. The Site is located approximately 1 mile east of the Pee Dee River and 1.6
miles southwest of Cordova, North Carolina on State Road 1103. As indicated on
Figure 1, the Site '* &§inPfi*~i,l AI eomprises two non-contiguous, independently
owned parcels of land: a 4O:acre tract owned by relatives and heirs of Charles Macon.
and a one-acre tract owned by John Dockery.
The Macon property is approximately 60 percent wooded. Several cleared areas are·
present at the Macon Site where drum storage areas, three unused surface
impoundments, and eleven oil/water waste storage lagoons were located. The
Dockery property is wooded with few cleared areas. One waste lagoon as well as
several drum storage areas were located in clearings on the Dockery Site.
I 1.2 LEAD AND SUPPORT AGENCIES
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EPA has been the CERCLA lead agency since initiating an immediate removal in 1983.
The Site was proposed for inclusion on the National Priorities List in January 1987 and·
finalized in July 1987. In April 1988, EPA entered into an Administrative Order on
Consent with two of the PRPs, Clark Equipment Company and Crown Cork and Seal
Company, to perform the Remedial Investigation and Feasibility Study.
The Record of Decision (ROD) was signed in September 1991. Negotiations for•
§~t!i~ffi~Q!f~g~rgjggimplementation of the Remedial Design/Remedial Action (RD/RA)
began in January 1992, but were unsuccessful. A Unilateral Administrative Order
(UAO) for implementation of the RD/RA was issued to 11 PRPs in June 1992. The
Remedial Design and associated activities have proceeded under an EPA enforcement
lead. EPA has consulted with the State of North Carolina with respect to response .
activities, and the NC Department of Environment, Health and Natural Resources (NC
DEHNR) has reviewed or commented on EPA decisions and PRP technical eomments g§94m@D1/l· The State of NC concurred with the original ROD.
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Record of Decision Amendment
Macon/Dockery Site
FIGURE 1
SITE LOCATION MAP
NORTH CAROLINA
STATE MAP
® --'-{c_'t-L, zy-c
LOCATION AND VICINITY MAP
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ROCKINGHAt,j•HM.!L[T
AIRPORT
Februer 1 994
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Record of Deciaion Amendment Februflry 1994
Macon/Dockery Site
1.3 CERCLA Section 117 and NCP Section 300.435(c){2)(ii)
The public participation requirements of both CERCLA Section 117 and Section
300.435(c)(2)(ii) of the NCP have been satisfied. A press release was issued, fact
sheets were sent to persons on EPA's Site mailing list and a newspaper advertisement
describing the proposed fundamental change and announcing the public comment
period was placed in a local newspaper. The public comment period was thirty (30)
days long.
1.4 ORIGINAL RECORD OF DECISION
The original ROD was signed by the Regional Administrator on September 30, 1991.
The ROD was later reissued on April 21, 1992. The State of North Carolina concurred
with the selected remedy.
1.5 SUMMARY OF THE CIRCUMSTANCES LEADING TO THE ROD AMENDMENT
In November 1982, under a state court order, the estate of Mr. Macon initiated
cleanup activities at the site. Hazardous materials were found stored at the Macon
portion of the site in more than 2,100 55-gallon drums, approximately 10 bulk tanks,
and 11 surface impoundments. When the estate funds were exhausted, NC
Department of Health Resources (DHR) requested EPA's assistance to complete the
cleanup operations. EPA initiated a removal at the Macon Site on November 11, 1983
and at the Dockery Site on January 9, 1984. Removal activities were completed on
January 17, 1984. After the removal action, the Site was evaluated to determine the
need for additional remedial measures. As a result of the evaluation, the
Macon/Dockery Site was added to the NPL in July 1987 with a score of 4 7 .10 out
of a possible 100 points on the Hazard Ranking System (HRS). Listing on the NPL
allows Superfund monies to be made available for remedial activities.
In April 1988, the Remedial Investigation/Feasibility Study (RI/FS) was initiated. The
RI/FS was submitted for public comment in July 1991. In August 1991, a public
meeting was held to present EPA's proposed plan and to solicit public comments. The
ROD was signed on September 30, 1991.
In January 1992, Special Notice Letters were sent to thirty-three (33) PRPs offering
them the opportunity of conduct the Remedial Design and Remedial Action (RD/RA).
Negotiations were unsuccessful and on June 18, 1992, EPA sent a Unilateral
Administrative Order (UAO) to eleven (11) of the PRPs ordering them to conduct the
RD/RA. Thereafter, a group of PRPs selected a design and construction supervising
contractor, and the RD was initiated.
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Record of Decision Amendment Februer 1994
Macon/Dockery Site
During the RD phase, additional studies were conducted to address the requirements
of the ROD and to fully delineate the groundwater plume. Additional studies consisted·
of: (1) twenty-seven (27) piezocones; (2) eleven (11) geocone soil samples; (3) one·
hun'dred (100) hydrocone groundwater samples; (4) fifteen (15) direct push well
points; (5) installation of one additional monitoring well; (6) groundwater samples .
collected from twenty-three (23) existing monitoring wells; (7) aquifer pumping test; ·
(8) bioassay testing; (9) soil vapor extraction pilot-scale evaluation which included the '
installation of one soil vapor extraction well and five soil vapor observation wells; (1 O) ·
bioremediation treatability study; ( 11) additional soil sampling of Lagoon 1 O; ( 12)
tir~m~i1fli~ii1ii~~t§§!§iti§riii~~iilii~1~ii!lllliilllltir f 12¥~~1~t"e~~~~!~~~!@l!l :
Remedial Design Report was submitted on August 25, 1993. EPA's comments on
this report were incorporated into the Intermediate (60%) RD which was submitted
to EPA on December 21, 1993.
1.6 ADMINISTRATIVE RECORD
The requirements set forth in Section 300.825(a)(2) of the NCP have been satisfied.
All majef documents that form the basis for the decision to modify the response '
action have been added to the administrative record file.
1.7 ADMINISTRATIVE RECORD AVAILABILITY
The administrative record file is available for viewing by the public during regular
business hours at the following locations:
Leath Memorial Library
412 East Franklin Street
Rockingham, North Carolina
USEPA Region IV Records Center
Ground Floor
345 Courtland Street, NE
Atlanta, Georgia 30365
[phone]
Copies of documents in the administrative record file may also be obtained from EPA's
Region IV Records Center in Atlanta by writing to the Freedom-of-Information Act
(FOIA) Coordinator and requesting a copy of the Macon/Dockery Administrative
Record Index. Choices of documents from the Index may be expressed in additional
FOIA requests.
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Record of Decision Amendment Februer 1994
M8con/Dockery Site
2.0 REASONS FOR ISSUING THE ROD AMENDMENT
2.1 DESCRIPTION OF THE REMEDY SELECTED IN THE ORIGINAL ROD
Section 10, page 117 of the original ROD, specified Alternative SC-4: Soil vapor
extraction (SVE) for Lagoon 7, bioremediation for Lagoon 10. The following is quoted,
from the original ROD:
"Implementation of the bioremediation phase of this alternative would be preceded by,
a treatability study to determine if the indigenous microbial population is capable of 1
degrading the i?!?lviriniijJp~~~[§Pir~iio~ (PAHs) in Lagoon 10. Other objectives of
the treatability study would include:
determine the percentage of endogenous microorganisms capable of
degrading PAHs;
determine whether the addition of acclimated microorganisms would be
necessary (bioaugmentation);
evaluate chemical/physical soil parameters (e.g., pH, moisture content,
nutrient content, dissolved oxygen content, etc.) and identify optimal
conditions for bioremediation; and
determine biodegradation kinetics and project treatment cycles.
A remediation level of 2.0 p~f;ijfpei;\fniJIJgp;(ppm) total carcinogenic PAHs for all
contaminated soil from Lagoon i6 will be required prior to replacing any residual i
material in the final disposal area. Final disposal of treatment residuals shall be
coordinated with EPA.
A significant reduction in PAH concentrations would be expected within 100 days
after treatment begins based on remediation at other sites. The wastes would be ,
sampled for volatile and semi-volatile analysis just prior to treatment and 100 days :
into treatment to determine whether target remediation levels have been achieved."
For groundwater, Section 10 of the original ROD specified Alternative GWC-2A:
Recovery and Treatment of all Site Groundwater exceeding groundwater remediation ,
levels using air stripping, coagulation/filtration. The ROD states:
"This remedial action will consist of a groundwater extraction and treatment system,
and an overall monitoring program for the Site. Groundwater contaminated above the ,
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Record of Decision Amendment Februar 1994
Macon/Dockery Site
remediation levels indicated in Table 57 will be extracted across the entire Site.
Treatment of groundwater will be accomplished by means of an air stripping tower.
The air stripper will remove the VOCs from the groundwater. Discharge of treated
groundwater will be either to a surface water (Solomons Creek) or to an infiltration
gallery. Due to the potential of having concentrations of metals above allowable'
levels in the effluent under the NPDES program, it may be necessary to reduce metal ·
concentrations in the groundwater prior to discharge. Metal removal from the
groundwater may consist of filtration/coagulation or some other cost effective
method."
The remediation levels for the three contaminants that follow are taken from Table 57,
page 118 of the original ROD.
Contaminant
Chloroform
Tetrachloroethene
Vinyl Chloride
Remediation Level
0.19 ug/1
0.7 ug/1
0.015 ug/1
2.2 SUMMARY OF RATIONALE FOR CHANGING REMEDY SELECTED IN THE
ORIGINAL ROD
2.2.1 Results of the Bioremediation Treatability Study
The treatability study called for by the ROD was conducted by the PRPs pursuant to ,
the UAO. The results of the treatability study were presented in the Preliminary ,
(30%) Remedial Design Report. The test showed that while the levels of PAHs were
I reduced, the performance standard of 2 ppm total carcinogenic PAHs would not be .
reached within 100 days, if at all (Table 1).
Resampling and reexamination of Lagoon 10 revealed that the material was a single,
hard, solid block with a density similar to common asphalt. This type of material is
not generally considered a good candidate for bioremediation. The material would
require pulverization at considerable expense in order for biodegradation to be even
slightly feasible. Even after pulverization, this type of material would not be
sufficiently bioavailable for degradation by microorganisms. The fact that the creosote
material is bound together to form a block suggest that it has a tar (sticky) component
that would be very difficult for microorganisms to attack. The presence of a sticky
substance would also cause mechanical difficulties in pulverizing and mixing the
waste. The probability of success for bioremediation is therefore considered low.
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Record of Decieion Amendment Februeir 1 994
Mecan/Dockery Site
TABLE 1
ANALYTICAL RESULTS OF BIOREMEDIATION STUDY
ANALYTICAL RESULTS OF PAHS IN BIOREACTORS:
PRESENTED BY MOLECULAR STRUCTURE•
{mg/kg dry weight)
::~:t~!ii!9:IYl!!!I!!i!~!i jiffil!ill~iRill!flif!: ii~l:I:it!R¼Yf:l!!I[~!i~t; if~]fflli!!lli!lill~ti :~!~!!! !?A'x;li~~!t
TWO RINGS {1-methyl naphthalene, 2-methyl naphthalene, naphthalene)
Unamended NA 2.15 (2) 2.31 (2) <1.48 (2) <0.88 (2)
Nutrient-Amended NA 6.57 (5) 1.39 (5) <16.17 (5) <4.86 (5)
Surfactant NA 2.65 (2) 1.41 (2) <1.00 (2) <1.02 (2)
THREE RINGS (acenaphthalene, acenaphthylene, anthracene, fluorene, phenanthrene)
Unamended 47.5 9.59 (2) 10.57 (2) <6.76 (2) <2.41 (2)
Nutrient-Amended 47.5 <16.79 (5) <3.28 (5) <16.30 (5) <11.46 (5)
Surfactant 47.5 <13.55 (2) <8.49 (2) <2.69 (2) <3.61 (2)
FOUR RINGS (benzo(a)anthracene•, chrysene•, fluoranthene, pyrene)
Unamended 33.0 13.74 (2) 21.01 (2) 20.02 (2) 8.96 (2)
Nutrient-Amended 33.0 21.38 (5) 10.56 (5) 17.94 (5) 12.58 (5)
Surfactant 33.0 14.31 (2) 11.69 (2) 9.44 (2) 7.46 (2)
FIVE RINGS (benzo(a)pyrene•,
dlbenzo(a,h)anthracene•)
benzo(b )fluoranthene•, benzo(k)fluoranthene•,
Unamended <36.8 2.90 (2) 5.88 (2) 5.04 (2) <2.62 (2)
Nutrient-Amended <36.8 4.72 (5) 4.44 (5) 6.09 (5) <4.68 (5)
Surfactant <36.8 2.64 (2) 3.43 (2) 3.08 (2) <3.02 (2)
SIX RINGS {benzo(g,h,l)perylene and lndeno(1,2,3-cd)pyrene")
Unamended <9.2 0.74 (2) 1.49 (2) 1.22 (2) 0.38 (2)
Nutrient-Amended <9.2 1.09 (5) 1.00 (5) 1.50 (5) 0.83 (5)
Surfactant <9.2 0.62 (2) 0.92 (2) 0.79 (2) 0.48 (2)
NA Not Analyzed.
a Mean value, with number of replicates in pamntheses.
b Carcinogenic PAHs.
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Record of Decision Amendment Februer 1994
Macon/Dockery Site
EPA has concurred with the finding that the higher molecular PAHsj~g!n~fi§f!«!)Jgfi
fff~carcinogenic, present in the waste would be very difficult to remediatetoatarget
level of 2 ppm biologically due to low bioavailability.
The soil vapor !!!lri!B!Hl!Jcomponent of the remedy f2rlfiQRHOi will remain the same.
2.2;2 Groundwater Performance Standards Evaluation
I EPA has reevaluated the groundwater performance standards listed in Table 57 of the:
original ROD. While the remediation levels presented are the most stringent between:
the NC Groundwater Standards and the Federal Maximum Contaminant Levels (MC Ls),
for three compounds, the standards are below the contract required quantitation limit·
I (CRQL). the lowest level that a laboratory can accurately identify. The performance·
standards for chloroform, tetrachloroethene, and vinyl chloride therefore, would never
be achieved because the laboratory could only report that the levels were under the :
CRQL, not necessarily below the performance standard.
3!0. REMAINlj(JG@AliTERNATIVes ggf.l§ll?~f{~p I~ ii'.l!l~)W!5Rl(1i.NAL f\Ql?if'.\'2R ·.·.·.·.·.·.·.·.u:a:nool\i10·············•·····
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Record of Decision Amendment Februer 1994 Macon/Dockery Site
4.0 DESCRIPTION OF THE MODIFIED REMEDY
4.1 COMPARISON OF THE ORIGINAL SELECTED SOIL REMEDY WITH THE
MODIFIED REMEDY
4.1.1 Original Soil Remedy's Treatment Component.
·Originally, approximately 1,000 cubic yards of contaminated soils in Lagoon 10 were
to be excavated and transferred to a lined waste treatment cell where bioremediation
would be conducted and monitored. The treatment cell would be enclosed within a
greenhouse-type structure that would serve to maintain optimum microbial growth
conditions and to control any air emissions. Vapor phase carbon adsorption would be
used as necessary to control emission concentrations from the greenhouse. A 100-
foot by 100-foot waste treatment cell would be lined with a 60-mil HOPE liner to
provide containment of the wastes. A 6-inch layer of sand and/or gravel would be
placed within the cell to provide a drainage layer for excess moisture. Applying a 6
to 8 inch layer of lagoon soils above the drainage layer would accommodate
approximately 200 cubic yards. Treated wastes would be returned to Lagoon 10
upon reaching the targeted remediation level of 2.0 ppm total carcinogenic PAHs. The
treatment residuals would be covered with a low permeability cap. The existing clay
at Lagoon 10 would be replaced and recompacted to form the cap. Refer to Section
10.0, page 123 and Section 8.0, page 102 of the original ROD; and to Section 6
of the Feasibility Study.
4.1.2 Modified Soil Remedy's Treatment Component.
Approximately 1,000 cubic yards of contaminated soils from Lagoon 10 would be
excavated and transported to an approved off-site disposal facility. The remediation
level of 2.0 ppm total carcinogenic PAHs would remain. Preliminary analyses of the
contaminated waste and current federal laws indicates that pre-treatment prior to
disposal is not necessary under current federal laws. However, additional testing will
be performed prior to excavation to determine if treatment §yffi~B!f!~l!@f?£i!itywill
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Record of Decision Amendment Februor 1 994 Macon/Dockery Site
be required prior to disposal. Lagoon 10 will be backfilled with native soils and
covered with compacted clay remaining from the cap. Refer to Section 8.0, page 103'
of the original ROD for more information.
I 4.2 COMPARISON OF THE ORIGINAL SELECTED GROUNDWATER REMEDY WITH I THE MODIFIED REMEDY
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4.2.1 Change in Groundwater Standards
The groundwater remediation levels will be changed as follows:
CONTAMINANT ORIGINAL REMEDIATION MODIFIED REMEDIATION
LEVEL ug/1 LEVEL ug/1
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Chloroform 0.19 NC GW Standard 1 CRQL I
Tetrachloroethene 0.7 NC GW Standard 1 CRQL
Vinyl Chloride 0.015 NC GW Standard 1 CRQL
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CRQL -Contract Required Quantitation Limit
NC GW Standard -North Carolina Groundwater Standards NCAC -15A-2L
4.2.3 Other GW Remedy Changes
The original ROD specified the discharge of the treated groundwater to either :
Solomon's Creek or to an infiltration gallery. Testing of infiltration galleries during the
RD proved to be successful, therefore, the treated groundwater will be discharged into
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a number of infiltration galleries onsite. See Section 2 of the Intermediate Design for'
further information.
In addition, the original ROD required metals removal by filtration/coagulation or some•
other cost effective method. Results of the bench-scale metals treatment evaluation
indicates that metals removal by ion exchange would be the best technology for the
present site conditions.
5.0 EVALUATION OF THE MODIFIED REMEDY
Both the original and the modified remedies for Lagoon 10 were evaluated in the •
original ROD. See Sections 7 and 11 of the original ROD for additional information.
5.1 Overall Protection of Human Health and the Environment
5.1.1 Original Remedy
The original remedy provided a permanent treatment for the Lagoon 10 contaminants .
thereby eliminating the dermal, ingestion and inhalation risks associated with the
wastes.
5.1.2 Modified Remedy
The modified remedy would remove the Lagoon 10 contaminants and thereby
eliminate the dermal, ingestion and inhalation risks associated with the wastes similar
to the original remedy.
5.2 Compliance with ARARs
5.2.1 Original Remedy
There are no ARARs governing subsurface soils at the Site. RCRA LOR is not an
ARAR for land treatment of Lagoon 10 materials. Bioremediation operations would
conform to North Carolina air emission requirements, as necessary.
5.2.2 Modified Remedy
Off-site disposal of soils would comply with EPA's off-site policy and land disposal
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I 5.3 Long-term Effectiveness and Permanence
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5.3.1 Original Remedy
The net reduction in chemical residual through bioremediation would require a
treatability study.
5.3.2 Modified Remedy
Off-site disposal of the Lagoon 10 wastes would permanently and effectively remove
the waste from the Macon/Dockery Site.
5.4 Reduction of Toxicity, Mobility. or Volume
5.4.1 Original Remedy
Bioremediation would effect a permanent but undetermined reduction in the volume
of chemical residuals in Lagoon 10.
5.4.2 Modified Remedy
The volume of chemical residuals at the Site would be significantly reduced through
off-site disposal of the Lagoon 10 waste materials.
5.5 Short-term Effectiveness
5.5.1 Original Remedy
This alternative would not pose a risk to the community or remedial workers through
implementation. Construction and operation is estimated at 25 -31 months.
5.5.2 Modified Remedy
!?X9~Y~l!i2n~ng pfffil!!~ S!i~PQ~?! §tH~fi§§n J;@m~i~fi~lf!This alterAative would not
pose a risk to the community or remedial workers through implementation. Removal
()PE;E~!i()~~ ~~()~1~ ~~ ?()TP1~!E;~ i: ~ ~()~~~~: DR~ tfa~ inr~itY ~JR~!m$1i~Jl§n Iit
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t§ fgj;j,Q§g :t~~ !~9j&!~t i!rij \g§t[!nijfg{!ll!fili!fi~l§fiQiO~!flQ!? ntii?Jii!'l 4P t~~¢h §t2:vn&JY¥ijtgt ri1mi21i1!2n!~x111~;
5.6 Implementability
5.6.1 Original Remedy
Actual implementation requirements for bioremediation would be established through
treatability testing.
5.6.2 Modified Remedy
§X!l~Y~t,2n ~!;!g Ptft§!!~ 2rn§§§?! gf l~?999RlJiQ m~t11rl~!~ This alternative could•.•.·.?~
readily implemented with no significant operational or administrative difficulties. ittil=! ~1f if ll~~!j)Itll~f i:Dn[I119 !?ier~miPi?t!§n §! sr§wn2!ixirir ~n, ei @~111rm!n¢a
5.7 Cost
5. 7 .1 Original Remedy
The present worth cost of the bioremediation is $1,130,000. See Table F. 7 in the
Macon/Dockery Feasibility Study.
5.7.2 Modified Remedy
The present worth cost of off-site disposal is $584,000. See Table F.8 in the
Macon/Dockery Feasibility Study. i'l;fj~ figi:)it19ij\9f)ifiji\jtqfijJqfgqi~tjJiltiPnlJP ;ii'\; ~
5.8 State Acceptance
5.8.1 Original Remedy
The State of North Carolina Department of Environment, Health and Natural Resources
concurred with the original ROD.
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APPENDIX A
ORIGINAL RECORD OF DECISION
Februar 1994,
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5.8.2 Modified Remedy
The NC DEHNR with this modified remedy.
5.9 Community Acceptance
5.9.1 Original Remedy
The community generally accepted the original remedy. See the Responsiveness
Summary in the original ROD.
5.9.2 Modified Remedy
6.0 STATUTORY DETERMINATIONS
6.1 Satisfaction of CERCLA Section 121
The modified remedy is protective of human health and the environment, complies
with ARARs, is cost effective, and utilizes permanent solutions and alternative
treatment technologies to the maximum extent practicable. Preference for treatment
as a principal element is satisfied by other aspects of the overall remediation of the
Macon/Dockery Site.
7.0 RESPONSIVENESS SUMMARY
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11 ORIGINAL RECORD OF DECISION
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