PB96-963804
EPA/ROD/R02-96/271
October 1996
EPA Superfund
Record of Decision:
Hercules Inc., (Gibbstown Plant),
Solid Waste Disposal Area, Operable Unit 3,
Greenwich Township, Gloucester County, NJ
1/22/1996
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SUPERFUND RECORD OF DECISION
HERCULES INCORPORATED
GREENWICH TOWNSHIP
GLOUCESTER COUNTY
NEW JERSEY
Prepared by: NJ Department of
Environmental Protection
Site Remediation Program
Bureau of Federal Case Management
JANUARY 1996
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HERCULES INCORPORATED SITE
RECORD OF DECISION
TABLE OF CONTENTS
DECLARATION STATEMENT.
DECISION SUMMARY.
1. Site Description 3
2 . Site History 3
3 . Ongoing or Completed Remedial Actions 4
4. Site Characteristics 4
5 . Highlights of Community Participation 6
6 . Summary of Site Risk 7
7 . Summary of Remedial Alternatives LO
8 . Summary of Comparative Analysis of Alternatives 12
9. Selected Remedy 18
10. Statutory Determinations : 19
11. Documentation of Significant Changes 20
GLOSSARY . 20
RESPONSIVENESS SUMMARY 24
APPENDIXES
FIGURES
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
TABLES
Table 1
Table 2
Table 3
Table 4
Table 5
Hercules Site Map
Map of the Solid Waste Disposal Area
Schematic Cross Section of Existing Conditions at the Solid
Waste Disposal Area
Conceptual Plan Engineered Soil Cap for the Solid Waste
Disposal Area
Schematic Cross Section Engineered Cap for the Solid Waste
Disposal Area
Hercules Ground Water Monitoring Well Network for the Solid
Waste Disposal Area
Administrative Record Index
Criteria "To Be Considered"
Location-Specific Applicable or Relevant and Appropriate
Requirements
Summary of Detailed Evaluation of Remedial Alternatives
Contaminants of Concern/Media of Concern
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DECLARATION STATEMENT FOR THE RECORD OF DECISION
SOLID WASTE DISPOSAL AREA (SWDA) - OPERABLE UNIT 3
HERCULES INCORPORATED SITE
Site Name and Location
Hercules Incorporated Site
Solid Waste Disposal Area (SWDA)-Operable Unit 3
Greenwich Township, Gloucester County, New Jersey
Statement of Basis and Purpose
This decision document presents the selected remedial action for the Solid Waste
Disposal Area (SWDA) - Operable -Unit 3, Hercules Incorporated, Higgins Plant
(hereinafter Hercules site or site), in Greenwich Township, Gloucester County, New
Jersey, which was chosen in accordance with the requirements of the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), as
amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA) 42
U.S.C. &9611 et. seq., and, to the extent practicable, the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP), 40 CFR Part 300 et. seq.
The New Jersey Department of Environmental Protection (NJDEP or Department)
maintains an Administrative Record at the NJDEP Information Resource Center in
Trenton and at the Gibbstown Public Library. Detailed in Section 5 herein, the
Administrative Record Index contains a listing of the documents which formed the
basis of the Department's selection of the remedy. This decision document
explains the factual and legal basis for selecting the remedy at the site.
Assessment of the Site
Actual or threatened releases of hazardous substances from this site, if not
addressed by the selected remedial alternative or one of the other active measures
considered, may present a current or potential threat to public health, welfare
or the environment.
Description of the Selected Remedy
The Record of Decision (ROD) addresses all contaminated media at the SWDA portion
of the site including soil and ground water. The selected remedy is a modified
version of the "In-Place Containment" remedy of the Proposed Plan.
The major components of the selected remedy are:
o Screening and collection for recycling of lead fragments from within the
SWDA.
o Consolidation of tar material and miscellaneous solid wastes under an im-
permeable cap. The impermeable cap will include a protective sub-layer and
an impermeable synthetic liner beneath two feet of clean soil and an upper
vegetative layer.
o Implementation .of engineering and institutional controls such as fencing
and environmental use restrictions.
o Establishment of a Classification Exception Area (CEA) for ground water
underneath and surrounding the SWDA. This will include annual evaluation
of ground water quality by the Department. An evaluation will determine
whether the remedy achieves federal Maximum Contaminant Levels (MCLs)
as well as New Jersey Ground Water Quality Standards (NJGWQS).
o Filling of the North Ditch with a 24-inch layer of clean imported soil.
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o Compensation/mitigation for natural resource damages.
Declaration of Statutory Determinations
The selected 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. The selection of this
remedy considered permanent solutions and alternative treatment (or resource
recovery) technologies to the maximum extent possible, and satisfies the statutory
preference for remedies that employ treatment that reduces toxicity, mobility, or
volume as their principal element.
This remedy will result in hazardous substances remaining on-site above health
based levels. Therefore, a review will need to be conducted pursuant to CERCLA
every 5 years to ensure that the remedy continues to provide adequate protection
of human health and the environment.
Date
rrcr-x
'Assistant Commissioner
Site Remediation Program
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DECISION SUMMARY
Decision Summary for the Record of Decision
Hercules, Inc. Site
Solid Waste Disposal Area (SWDA)-Operable Unit 3
Gibbstown, New Jersey
1. SITE DESCRIPTION
The Hercules site is located at the end of North Market Street in Gibbstown,
Greenwich Township, Gloucester County, New Jersey. The site consists of
approximately 350 acres and is bounded by the Delaware River to the north, Mobil
Oil Corporation's (Mobil) petroleum refinery to the east, the community of
Gibbstown to the south, and E.I. du Pont de Nemours Incorporated's (DuPont)
manufacturing plant to the west. The site is approximately one mile west of
Interstate 295. Clonmell Creek, a tributary of the Delaware River, runs northwest
through the middle of the site. The site consists of developed and undeveloped
uplands with swampy inner lowland areas extending between Clonmell Creek and the
Delaware River.
Hercules' manufacturing facilities cover approximately 40% of the southern portion
of the site. The SWDA, which is the subject of this Record of Decision (ROD),
consists of approximately 4 acres and is situated between the plant's
manufacturing facilities and a levee which runs along the Delaware River (Delaware
River levee) to the north. Ground surface elevations range from a maximum of 18
feet above mean sea level (msl) at the southern end of the site to a minimum of
2 feet above msl at the northern end of the site adjacent to the Delaware River.
The Hercules site is located within the Atlantic Coastal Plain Physiographic
Province. This geologic province is characterized by the presence of a sequence
of thick unconsolidated sand, silt, gravel and clay. The major stratigraphic
units present in the area are from oldest to youngest: Pre-Cambrian Age (greater
than 600 million years) crystalline basement rocks, deposits of Cretaceous Age
(135-60 million years old) Potomac-Raritan-Magothy Formation, Pleistocene Age
(500,000 to 11,000 years old) deposits of the Trenton Gravel (formerly referred
to as the Cape May Formation), and Holocene (11,000 years old to present) alluvial
deposits on the Delaware River floodplain. The geology underlying the SWDA
consists of the surficial Peat/Clay and underlying Sand unit.
The Hercules property north of Clonmell Creek, including the SWDA, is within the
100 year floodplain of the Delaware River. The SWDA proper is classified as a
disturbed old field forested upland. The SWDA is composed of two tar disposal.
areas with intermingled solid wastes which are transected by a dirt access road.
The Delaware River levee separates the SWDA and the Delaware River. A prominent
swale located north of the SWDA and at the base of the Delaware River levee is
referred to as the North Ditch. A remnant of a manmade system of ditches used to
convert wetlands to farmland during, the 1940s, the North Ditch has been determined
to be a closed system with no inlet or outlet.
2. SITE HISTORY
In 1952, the Hercules Powder Company obtained the area which encompasses the SWDA
from DuPont. Historical aerial photographs reveal that tars present within the
SWDA were placed there prior to Hercules' purchase of the property. Reportedly,
tars generated by aniline production at the DuPont facility were transported by
rail car and tank trucks and disposed of in the SWDA. Lead fragments from lead
troughs and tubs were also reportedly disposed of in this area. From 1955 to 1974 .
Hercules used the SWDA to dispose of mixed waste materials from manufacturing
processes at the Gibbstown Plant. According to plant personnel, a road was built
to accommodate dump trucks travelling to and from the main plant to the SWDA.
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This road was also used for the maintenance of the plant's waste water treatment
discharge line. Waste disposal ended in 1974 and the area has remained inactive
since that time.
A report entitled "Water Quality Data for the Potomac-Raritan-Magothy Aquifer
System, Trenton to Pennsville, New Jersey, 1980" was released in 1981 which
documented volatile organic (benzene) ground water contamination found in
production well 4 (PW4) at Hercules. In December 1982, as a consequence of this
investigation and the existence of tar pits and disposal areas located in the
northern portion of the plant property (the SWDA), Hercules was listed on the
National Priorities List (NPL). In 1983, Hercules initiated Remedial
Investigations and Feasibility Studies (RI/FS) for the entire site. In 1984,
Hercules commenced contaminated ground water recovery, treatment, and disposal for
the main plant.
In July 1986, Hercules entered into an Administrative Consent Order (AGO) with the
NJDEP. The AGO required Hercules to continue operation of its existing ground
water treatment system and to investigate all other areas of concern at the site.
Initial investigations identified the SWDA as separate and distinct from all other
areas of the site. Therefore, Hercules conducted a separate and distinct
investigation of the SWDA. This Record of Decision (ROD) will address the SWDA
of the Hercules site.
3. ONGOING OR COMPLETED REMEDIAL PROGRAMS
As with many Superfund sites, the problems at the Hercules site are complex. As
a result, NJDEP has currently organized the remedial work into three operable
units. These units consist of contaminated ground water, on-site soils, and the
SWDA. In 1984, as an interim measure, Hercules commenced recovery and treatment
of contaminated ground water from the main plant portion of the site. On-site
soils are currently being investigated as contaminated soils appear to be the
source of much of the ground water contamination and are a direct contact threat
to site workers. The third operable unit is the SWDA. The selected remedy for the
SWDA is a modified version of the In-Place Containment remedy presented in the
Proposed Plan. This remedy will include maintenance and upgrading of control
measures, the implementation of environmental use restrictions, creation of a CEA,
and ground water monitoring.
The SWDA has undergone three phases of remedial investigation. Phase I was
initiated in May 1987 and was conducted over a one year period. Phase I included
historical research concerning disposal practices and delineation of the SWDA, as
well as soil and ground water sampling.
Phase II, implemented iij 1989, intended to further define the -extent and
distribution of wastes, determine the characteristics of the tar and other
materials disposed of in the SWDA, further address the presence or absence of
possible contamination in the soils and ground water surrounding the SWDA, and
identify any relationships between waste and ground water in the SWDA. Phase II
also provided additional information with respect to areal extent of
contamination, amount of contamination, and disposition of the tar. Additionally,
Phase II confirmed that ground water flow is predominately south toward the main
part of the plant and fluctuates with tidal conditions in the Delaware River.
Phase III was initiated in 1993 in order to collect additional miscellaneous
information and data which was needed to further delineate contamination found in
the SWDA. This information would ultimately be used in order to determine an
appropriate remedy based upon the areas of concern which comprise the SWDA.
4. SITE CHARACTERISTICS
The media of concern within the SWDA are described below:
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TAR MATERIAL
The tar pits in the SWDA are estimated to cover a total area of approximately
158,600 square feet, including both exposed tars and tars covered by the solid
waste materials. The tar material is a distillation by-product from the.
purification of aniline and contains diphenylamine, N-nitrosodiphenylamine,
benzidine, aniline^ phenols and metals. The thickness of the tar is believed to
be varying, with an average thickness of 3 feet. Samples of the tar were
collected from' the SWDA in order to quantify the physical characteristics of the
tar for an engineering evaluation of capping options. The data collected
confirmed observations taken in the field that the tar can resist some loading at
low temperatures, but at elevated temperatures the tar has minimal load bearing
capacity. The tar in its pure state (aniline still bottoms) has been
characterized as a heavy liquid displaying characteristics similar to those of
No.6 fuel oil. At cold temperatures, typical of winter conditions, the exposed
tar becomes rigid and has the capacity to carry significant loads (e.g., it can
be walked on with little or no deformation). It is known that the tar material,
at temperatures existing beneath ground surface has sufficient bearing capacity
to support the weight of the solid waste because the tar is overlain in many
places by as much as 4 to 6 feet of solid waste. The bearing capacity or strength
of the tar is believed to result from 'a combination of its high viscosity and
confined in-situ state.
.. SOILS
Soils underlying the tar contain benzo(a)pyrene, diphenylamine, phenols, and
metals in low levels. Benzo(a)pyrene at 830 ug/kg was the only constituent
exceeding the NJDEP Soil Cleanup Criteria. Lead was the only metal found in the
form of solid fragments within the SWDA. This lead is leachable and exceeds the
TCLP leachate standard of 5 mg/L. Pesticides found in the soil were not
manufactured by Hercules and are considered generic to the region.
MISCELLANEOUS SOLID WASTES
Based on the Phase III RI Report, the miscellaneous solid waste piles within the
SWDA contain plant process wastes and inert construction debris including waste
scrap material, spent alkylation catalyst, cumic acid, sodium thiocyanate filter
cake, DALPAC (butylated hydroxy toluene, BHT) and off-specification materials
contaminated with toluene, phenol, p-cresol, di-tertiary butyl p-cresol, di-
methylbenzyl alcohol, and dicumyl peroxide. These wastes cover an area of 93,650
square feet and are unaffected by volume change due to material degradation. The
physical behavior of these wastes seems fairly consistent throughout the waste
mass, yet the mass is highly heterogeneous and varying in thickness.
GROUND WATER
As mentioned previously, in 1984 Hercules implemented a ground water recovery
system to control off-site migration of contaminated ground water from the main
portion of the plant. In 1991 as part of this system, an expanded waste water
treatment plant began operations. Migration of chemical compounds to the upper
portion of the Potomac-Raritan-Magothy (PRM) aquifer is impeded beneath the SWDA
where the peat/clay layering is present. No chemical compounds were detected in
the lower portion of the PRM aquifer above current NJGWQS. The Phase II study of
the SWDA confirmed that ground water flow is predominately south toward the main
part of the plant and fluctuates with tidal conditions in the Delaware River.
There is also a slight net downward vertical hydraulic gradient in the water table
due to heavy ground water usage in the surrounding area. The final Phase III RI
Report for the SWDA related ground water flow to tidal activity, stating that
ground water flow is influenced by tidal activity, precipitation, surface water
runoff and leakage from the Delaware River levee. Ground water quality is
influenced by the slight exceedances of volatile organic compound (VOC) standards
in the immediate vicinity of the solid waste and tar pits (specifically MW-13 and
MW-40 see Figure 5). These exceedances are not detected in down gradient
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monitoring wells. Total lead and total chromium detections (unfiltered sample
analysis) in MW-41, MW-42, MW-43 exceeded the current NJGWQS (see Figure 6). The
primary constituents of concern are toluene, cumene, benzene, 2,4 and 2,6
dinitrotoluene, arsenic, lead, nickel, and zinc. Dissolved phase constituents
were not detected in monitoring wells near the Delaware River.
SURFACE WATER
Concentrations of aluminum, lead, zinc and DDT detected in surface water from the
North Ditch exceeded the Federal Ambient Water Quality Criteria. Since the ditch
represents a closed system, the constituents found in the North Ditch do not
migrate out of the ditch.
SEDIMENTS
Concentrations of cumene, diphenylamine, phenols, PAHs, PCBs, and pesticides were
detected in North Ditch sediments exceeding NOAA Criteria. The sediments do not
appear to impact ground water quality as evidenced by monitoring wells located
between the SWDA and the North Ditch.
AIR QUALITY
Results of air sampling indicate that VOCs are not being released from the SWDA
under ambient conditions. Thus, no contaminant transport mechanisms via air were
detected.
5. HIGHLIGHTS OF COMMUNITY PARTICIPATION
The RI/FS Report and the Proposed Plan for the SWDA were released to the public
for comment on July 27, 1994. These two documents in addition to the documents
detailed below were made available to the public in both the administrative record
and information repositories maintained at the NJDEP Information Resource Center,
at the Gibbstown Public Library and at the Greenwich Township Municipal Building.
The notice of availability for these two documents was published in the Gloucester
County Times on July 27, 1994. A public comment period on the Proposed Plan was
held from July 27, 1994 to August 25, 1994. In addition, a public meeting was
held on August 10, 1994. At this meeting, representatives from NJDEP answered
questions about problems at the site and the remedial alternatives under
consideration." A response to the comments received during this period is included
in the Responsiveness Summary, which is part of this ROD.
The documents listed below which comprise the Administrative Record for this ROD,
were made available to the public for review:
o Administrative Consent Order entered into between Hercules
and NJDEP; Paragraph 34 requires Hercules investigation of
the Solid Waste Disposal Area (July 1986)
o Phase I Work Plan (September 1986)
o Results of Phase I Investigation of the Solid Waste Disposal
Area (March 1988)
o Addendum to Results of Phase I Investigation (September 1988)
o Phase II Investigation Scope of Work (September 1988)
o Phase II Supplemental Investigation Scope of Work (February 1989)
o Phase II Remedial Investigation Results, Solid Waste Disposal
Area, Higgins Plant (June 1989)
o Phase II Addendum, Hercules Plant (June 1990)
d Phase III Remedial Investigation Work .Plan and Quality Assurance
Project Plan, QAPP (April 1992)
o Response to Comments on Phase III Remedial Investigation Work Plan
(June 1992)
o Revised QAPP for the Solid Waste Disposal Area Remedial Investigation
(June 1992)
o Revised Table 4-1 of the QAPP (July 1992)
o Analytical Method for Differentiation of Diphenylamine/Nitro-
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sodiphenylamine in QAPP (August 1992)
o Phase III Remedial Investigation, Solid Waste Disposal Area (February
1993) .
o NJDEP Approval of Remedial Investigation Activities (May 1993)
o Final Revised Feasibility Study (October 1993)
o Revised Risk Assessment (December 1993)
6. SUMMARY OP SITE RISK
Based upon the results of the RI, a baseline risk assessment was conducted to
estimate the risks associated with current and future site conditions. The
baseline risk assessment estimates the human health and ecological risk which
could result from the contamination at the site if no remedial action were taken.
Site risks are expressed in exponential terms when'estimating the cancer risk.
For example, 1 x 10"6 excess cancer risk estimate means that a person exposed to
contaminants in the SWDA would experience a one in one-million excess risk of
developing cancer over their lifetime. Risk of health effects other than cancer
are expressed in terms of a calculated Hazard Index. A Hazard Index greater than
one (1.0) for an individual exposed to site contaminants in a specified manner
over a lifetime would indicate a potential for health effects other than cancer.
Human Health Risk Assessment
The conservative estimate of reasonable maximum human exposure is evaluated. A
four-step process is utilized for assessing site-related human health risks for
a reasonable maximum exposure scenario: Hazard Identification—identifies the
contaminants of concern at the site based on several factors such as toxicity,
frequency of occurrence, and concentration. Exposure Assessment—estimates the
magnitude of actual and/or potential human exposures, the frequency and duration
of these exposures, and the pathways (e.g., ingesting contaminated well-water) by
which humans are potentially exposed. Toxicity Assessment— determines the types
of adverse health effects associated with chemical exposures, and the relationship
between magnitude of exposure (dose) and severity of adverse effects (response).
Risk Characterization— summarizes and combines outputs of the exposure and
toxicity assessments to provide a quantitative (e.g., one-in-a-million excess
cancer risk) assessment of site-related risks.
Reference doses (RfDs) have been developed by EPA for estimating excess adverse
health effects from exposure to chemicals exhibiting noncarcinogenic effects.
RfDs, which are expressed in units of mg/kg-day, are estimates of lifetime daily
exposure levels for humans, including sensitive individuals, that are not likely
to be without an appreciable risk of adverse health effects. Estimated intakes
of chemicals from environmental media (e.g., the amount of a chemical ingested
from contaminated drinking water) can be compared to the RfD. RfDs are derived
from human epidemiological studies or animal studies to which uncertainty factors
have been applied (e.g., to account for the use of animal data to predict effects
on humans). These uncertainty factors help ensure that the RfDs will not
underestimate the potential for adverse noncarcinogenic effects to occur.
Cancer potency factors (CPFs) have been developed by EPA's Carcinogenic Assessment
Group for estimating excess lifetime cancer risks associated• with exposure to
potentially carcinogenic chemicals. CPFs, which are expressed in units of (mg/kg-
day)"1, are multiplied by the estimated intake of a potential carcinogen, in
mg/kg-day, to provide an upper-bound estimate of the excess lifetime cancer risk
associated with exposure at that intake level. The term^ "upper bound" reflects
the conservative estimate of the risks calculated from'the CPF. Use of this
approach makes underestimation of the actual cancer risk highly unlikely. Cancer
potency factors are derived from the results of human epidemiological studies or
chronic animal bioassays to which animal-to-human extrapolation and uncertainty
factors have been applied.
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Excess lifetime cancer risks are determined by multiplying the intake level with
the cancer potency factor. These risks are probabilities that are generally
expressed in scientific notation (e.g., 1x10"* or 1E-6). An excess lifetime
cancer risk of IxlO"6 indicates that, as a plausible upper bound, an individual
has a one in one million chance of developing cancer as a result of site-related
exposure to a carcinogen over a 70-year lifetime under the specific exposure
conditions at a sitee.
Potential for noncarcinogenic effects from a single contaminant in a single medium
is expressed as the hazard quotient (HQ) (or the ratio of the estimated intake
derived from the contaminant concentration in a given medium to the contaminant's
reference dose). By adding the HQs for all contaminants within a medium or across
all media to which a given population may reasonably be exposed, the Hazard Index
(HI) can be generated. The HI provides a useful reference point for gauging the
potential significance of multiple contaminant exposures within a single medium
or across media.
The baseline risk assessment began with selecting contaminants of concern which
would be representative of site risks (see Table 5). These contaminants included
benzene, cumene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, diphenylamine, arsenic,
benzidine, chromium, benzo(a)pyrene, and mercury. Three of the contaminants,
arsenic, benzene, and benzidine, are known to cause cancer in laboratory animals
and are known to be human carcinogens.
The baseline risk assessment evaluated the health effects which could potentially
result from exposure to contamination as a result of dermal contact, ground water
ingestion, inhalation of released chemicals and incidental inhalation of soil and
waste. The potentially affected population consists of an occasional employee and
adult trespasser. Younger children were not considered part of the potentially
exposed population due to the limited access and terrain in the immediate vicinity
of the SWDA.
Under the hypothetical ground water use conditions, employees at the Hercules
facility represented the potentially affected population. Exposure pathways
evaluated are: a) inhalation of VOCs and skin contact with and ingestion of com-
pounds detected in ground water at the source area; b) skin contact with and
incidental ingestion of surface soil and tar; and c) skin contact with and
incidental ingestion of surface water and sediments at the North Ditch. In-
halation was not considered an exposure pathway as VOCs generally have not been
detected in tar and surface soil samples, and field screening instruments used
during intrusive sampling events did not detect VOCs. The possibility of the
above exposures actually occurring is remote as the area is virtually inaccessible
to the public and the majority of plant employees. Access to the SWDA is limited
to a few personnel at the plant who have keys to the locked gate separating the
SWDA waste from the main plant portion of the site. There is a remote possibility
that the occasional trespasser walking along the Delaware River levee could access
the area. There are no plans to develop or expand current .plant operations in the
immediate vicinity of the SWDA.
Summary of Health Risks
The results of the baseline risk assessment indicate that the tar and tar/soils
at the site pose an unacceptable risk to human health. The maximum carcinogenic
risk is associated with direct exposure to tar and tar/soils. The risk for a
worker or adult trespasser is estimated to be 8xlO"3. This risk number means that
an individual exposed to the contaminants with the frequency and duration outlined
in this scenario would experience an 8 in 1,000 excess risk of developing cancer.
Benzidine is the chemical of concern which is primarily responsible for the
potential risk associated with tar exposure.
The Hazard Index, which reflects noncarcinogenic effects for a human receptor, was
estimated to be 0.57 for all media combined. The Hazard Index does not exceed
1.0, indicating that non-carcinogenic health effects are not of concern at the
site. Current federal guidelines for acceptable exposures are a maximum health
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Hazard Index equal to 1.0 and an individual lifetime excess carcinogenic risk in
the range of 10'* to 10~°. The State of New Jersey has developed remedial criteria
based on the risk level of 1 x 1CT6 for carcinogens and a Hazard Index of 1.0 for
noncarcinogens.
As discussed previously, ground water quality has exhibited elevated concen-
trations of VOCs in the immediate vicinity of the SWDA. However, there is no
evidence that VOCs have migrated to down gradient monitoring wells. Thus VOC
exceedances have not been determined to pose a threat to local potable wells or
to the Delaware River. Additionally, the selected alternative will establish a
CEA pursuant to the NJGWQS N.J.A.C. 7:9-6 et sea, for ground water underneath and
surrounding the SWDA which will restrict the use of ground water for potable
purposes.
Actual or threatened releases of hazardous substances from this site, if not
addressed by the selected alternative or one of the other active measures
considered, may present a current or potential threat to public health, welfare
or the environment.
Ecological Risk Assessment
The reasonable maximum environmental exposure is evaluated. A four-step process
is utilized for assessing site-related ecological risks for a reasonable maximum
exposure scenario: Problem Formulation— a qualitative evaluation of contaminant
release, migration, and fate; identification of contaminants of concern,
receptors, exposure pathways, and known ecological effects of the contaminants;
and selection of endpoints for further study. Exposure Assessment—a quantitative
evaluation of contaminant release, migration, and fate; characterization of
exposure pathways and receptors; and measurement or estimation of exposure point
concentrations. Ecological Effects Assessment—literature reviews, field studies,
and toxicity tests, linking contaminant concentrations to effects on ecological
receptors. Risk Characterization—measurement or estimation of both current and
future adverse effects.
The ecological risk assessment began with evaluating the contaminants associated
with the site in conjunction with the site-specific biological species/habitat
information. Direct exposure to the tar/soils and tar pits within the SWDA
represents the dominant pathway of site-related contaminants to terrestrial
wildlife that frequent or inhabit the SWDA. The major transport mechanism of site
contaminants to the aquatic communities within the common reed wetland and the
North Ditch appears to be from runoff and overland flow from the SWDA. Exposure
to the sediment and surface water represents the dominant pathway of contaminants
to aquatic invertebrates, fish, reptiles, amphibians, and waterfowl. The tran-
sitory presence of potentially contaminated tadpoles and invertebrates within the
North Ditch provides a pathway by which transient migratory species, especially
wading birds may ingest the contamination. Low level estimated concentrations of
pesticides and PCB concentrations were highest at the reference station and likely
represent background conditions in the area.
The results of the ecological risk assessment indicate that the contaminated
soils, sediment, and tar may pose some risk at the site. No acute impacts were
observed in the aquatic organisms within the North Ditch. The compounds detected
in the North Ditch are likely sorbed onto the high organic content sediments.
Since the ditch represents a closed system, these constituents do not migrate out
of the Ditch. No acute impacts were noted in wildlife observed during field
reconnaissance. The SWDA has a limited wildlife habitat and the vegetation
present does not provide quality food for wildlife, therefore, limited exposure
would only occur to species which occasionally pass through the SWDA. However,
since chronic exposure to site related contaminants will persist, implementation
of remedial actions will eliminate the possibility of chronic exposures to the
communities now subject to risk.
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SCOPE AND ROLE OF ACTION
The remediation of the Hercules site will consist of at least three operable units
with separate and distinct Records of Decision. One will address the SWDA area
(the subject of this ROD) and the remaining two will address contaminated ground
water and the main plant portion of the site. The purpose of this remedial action
is to alleviate the risk to human health and the environment associated with the
SWDA at the Hercules Plant. This is a separate and distinct operable unit which
is unique in character and location with respect to the overall site.
The most serious risk from the SWDA is direct exposure of hazardous substances to
a transient population of wildlife and the occasional plant employee or
trespasser. Therefore, the proposed remedies must address these concerns.
Limiting access to the area and limiting exposure pathways from the hazardous
substances should result in all risk associated with this area being within
acceptable levels. Restricting the use of the ground water will also eliminate
exposure to- risk through ingestion of ground water.
7. SUMMARY OF REMEDIAL ALTERNATIVES
CERCLA requires that each selected remedy be protective of human health and the
environment; be cost effective; comply with other statutory laws; and utilize
permanent solutions, alternative treatment technologies, and resource recovery
alternatives to the maximum extent practicable. In addition, the statute includes
a preference for the use of treatment as a principle element for the reduction of
toxicity, mobility, or volume of the hazardous substances.
Identification and screening of potential remedial technologies for tars and solid
wastes were reviewed for purposes of the Feasibility Study. Several of these
technologies were identified but eliminated during preliminary assessments due to
lack of effectiveness, implementability, or pertinence. The following
technologies were initially screened out: aeration, in-situ biodegradation, in-
situ vitrification, soil flushing, solvent extraction, stabilization/
solidification, thermal desorption, and vapor extraction. Subsequent screening of
remedial technologies reduced the list to four.
The FS Report evaluates the four (4) remedial alternatives for addressing the
contamination associated with the Solid Waste Disposal Area of the Hercules site
in detail.
These alternatives are:
1. No Action
2. Limited Action
3. In-Place Containment
4. On-Site Incineration/Off-Site Disposal and
Ground Water Pump and Treat
A brief description of each of the remedial alternatives is provided below:
Alternative #1 - No Action:
The Superfund program requires that the "no-action" alternative be considered as
a baseline for comparison of all other alternatives. The No Action alternative
consists of long-term periodic site inspection and ground water monitoring.
Because this alternative would result in contaminants remaining on-site, CERCLA
requires that the site be reviewed every five years. If justified by the review,
remedial actions may be implemented to remove or treat the waste.
Capital Cost: $ 0.00
Annual Cost: §10,060
Present Worth Cost: $201,040
Time to Implement: 6 months
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Alternative #2 - Limited Action:
This alternative requires periodic inspection, ground water monitoring and
institutional controls that would reduce the potential for exposure to site
contaminants. Specifically, semi-annual inspections would be made of the entire
SWDA, annual ground water sampling and analysis would be performed, environmental
use restrictions and engineering controls would be imposed, and a perimeter fence
would be installed around the SWDA. Because this alternative would result in
contaminants remaining on-site, CERCLA requires that the site be reviewed everv
five years. If justified by the review, additional remedial actions may be
implemented to remove or treat the solid waste and tar.
Capital Cost: $256,750
Annual Cost: $11,060
Present Worth Cost: $476,000
Time to Implement: 1 year
Alternative #3 - la-Place Containment:
Under this alternative tar material and miscellaneous solid wastes would be
consolidated and remain under a flexible, impermeable cap. Prior to the placement
of select soils from within the SWDA, lead fragments would be screened out and
collected for recycling. An engineering control in the form of a fence would be
installed to prevent trespassers and unauthorized personnel from entering the
area. Inspections, ground water monitoring, and institutional controls would also
be implemented. Specifically, semi-annual visual inspections of the SWDA would
be performed. Ground water sampling and analysis would occur. Environmental use
restrictions and engineering controls would be imposed. The smaller outlying tar
material areas and miscellaneous solid wastes from the entire SWDA would be
consolidated with the large tar pits, regrading of the area will also occur, an
impermeable cap would be put in place over the tar and solid waste, and storm
water controls would be instituted. The impermeable cap would consist of a multi-
layer system consisting of an upper vegetative layer underlain by approximately
2 feet of clean soil, an impermeable synthetic membrane liner and a protective
sub-layer for the liner, or the "equivalent". This cap would be keyed into the
existing native soil to prevent migration of the tars during temperature
fluctuations. The existing contaminated sub-soil would be graded and inspected for
large protrusions which may breech the integrity of the liner. All damages to
natural resources will be mitigated/compensated for. All necessary permits will
be secured.
In addition, the NJDEP will designate a CEA for ground water underneath and
surrounding the SWDA. Because the ground water quality exceedances do not
currently pose an unacceptable threat to local potable wells or the Delaware
River, active ground water remediation is not included in this alternative for the
SWDA. The designation of the CEA and the Department's acceptance of monitoring for
the ground water remedy does not preclude the Department from requiring an active
ground water recovery system should deterioration in the ground water quality
occur in this area. This can be accomplished by installing recovery wells down
gradient of the SWDA and linking into the existing on-site water treatment system.
Because this alternative would result in contaminants remaining on-site, CERCLA
requires that the site be reviewed every five years. If justified by the review,
remedial actions may be implemented to remove or treat contaminated media.
Capital Cost: $1,715,107
Annual Cost: $17,460 .
Present Worth Cost: $1,956,000
Time to Implement: 3 years
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Alternative #4 - On-Site Incineration, Off-Site Disposal and Ground Water Pump and
Treat System
This alternative requires excavation of miscellaneous solid wastes within the
SWDA, screening for lead fragments, and off-site disposal of the solid waste. The
tar would be excavated and staged for on-site incineration as would some of the
solid wastes which would be commingled with the tar. The resultant ash would be
disposed of off-site. Although the ground water in the vicinity of the SWDA has
been observed to be only minimally impacted by site constituents, ground water
recovery and treatment has been evaluated in this ROD for completeness. Treatment
of ground water, if necessary, would be accomplished using the existing Hercules
treatment facility. Annual ground water monitoring would be performed and
institutional controls would be imposed to restrict future water usage. Lead
fragments would be mechanically screened and recycled. Pre-construction activities
would be performed that include construction of a staging area, access road
improvements, clearing and grubbing of vegetation, institution of erosion and
sedimentation controls, and partial replacement of an existing waste water
pipeline. In addition, a remote area would be cleared for the construction of a
permanent or mobile incinerator. Wetland permits would be necessary due to the
extensive intrusive work required in the wetlands and in the North Ditch. The
structuring and operational permitting of an on-site incinerator would also be
required. Additional backfilling and grading in the SWDA would be required to
promote proper storm water drainage. All damages to natural resources would be
mitigated/compensated for.
Capital Cost: $ 36,728,250
Annual Cost: $7,360
Present Worth Cost: $36,875,000
Time to Implement: 5 years
8. SUMMARY OP COMPARATIVE ANALYSIS OF ALTERNATIVES
During the detailed evaluation of remedial alternatives, each alternative was
assessed against nine evaluation criteria. These criteria are: overall
protection of human health and the environment, compliance with applicable or
relevant and appropriate requirements, long term effectiveness and permanence,
reduction of toxicity, mobility, or volume, short-term effectiveness,
implementability, cost, and EPA and community acceptance.
o Overall Protection of Human Health and the Environment
Overall protection of human health and the environment addresses whether or
not a remedy provides adequate protection and describes how risks posed
through each pathway are eliminated, reduced, or controlled through treat-
ment, engineering controls, or institutional controls. Overall protection
of human health and the environment represents a threshold criterion.
o Compliance with ARARs
Compliance with applicable or relevant and appropriate requirements (ARARs)
addresses whether or not a remedy will meet all of the applicable or rel-
evant and appropriate requirements of other federal and state environ-
mental statutes and requirements or provide grounds for invoking a waiver.
o Lono-Term Effectiveness and Permanence
Long-term effectiveness and permanence refers to the ability of a remedy to
maintain reliable protection of human health and the environment over time,
once cleanup goals have been met.
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o Reduction of Toxicitv, Mobility, or Volume through Treatment
Reduction of toxicity, mobility, or volume through treatment is the antic-
ipated performance of the treatment technologies a remedy may employ.
o Short Term Effectiveness
Short-term effectiveness addresses the period of time needed to achieve
protection arrd any adverse impacts on human health and the environment that
may be posed during the construction and implementation period until cleanup
goals are achieved.
o Implementabilitv
Implementability is the technical and administrative feasibility of a
remedy, including the availability of materials and services needed to
implement a particular option.
o Cosjt
Cost includes estimated capital and operation and maintenance costs, and net
present worth costs.
o EPA Acceptance
EPA concurrence indicates whether the federal regulatory agency concurs,
opposes,, or has no comment on the selected remedy. EPA concurrence is not
a prerequisite in NJDEP's selection of a remedial alternative.
o Community Acceptance
Community acceptance assesses the public comments received on the RI/FS
Reports and the Proposed Plan.
Community concerns/comments received during the public comment period and
the public meeting held on August 10, 1994, are included in the Respon-
siveness Summary, together with NJDEP responses, which are a part of this
ROD. Community concerns/comments received generally indicate that the
community accepts the preferred alternative identified in the Proposed
Plan and selected in the ROD.
A comparative analysis of these alternatives based upon the evaluation noted above
follows:
o Overall Protection of Human Health and the Environment
Alternative #1 - No Action
The only activities performed on-site would be periodic .inspections and ground
water monitoring. Therefore, there would be no significant short-term risks
associated with this alternative. The existing carcinogenic risk due to direct
contact with the tar material and the potential for migration of constituents
would not be reduced. This alternative would not adequately satisfy the remedial
action objectives in terms of potential risk to public health.
Alternative #2 - Limited Action
This alternative would reduce the potential for exposures to site constituents
through institutional controls such as site fencing and environmental use
restrictions. However, the potential for migration of constituents would not be
reduced. For all media except the tar, this alternative would adequately satisfy
the remedial action objectives in terms of potential risk to public health.
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Alternative #3 - la-Place Containment
This alternative would mitigate the potential for direct contact with the tar
material and miscellaneous solid wastes. The potential for migration of
constituents due to surface erosion would also be mitigated. Periodic site
inspections and maintenance would ensure the longevity of the cover, and ground
water monitoring would provide an assessment of changes in the ground water
quality. Additionally, the impermeable liner will help prevent ground water
degradation from potential leaching of hazardous constituents from the solid waste
material. Short-term risks associated with the extraction of small quantities of
tar and solid wastes would be mitigated through proper health and safety
procedures.
Alternative #4 - On-Site Incineration and Off-Site Disposal
This alternative would eliminate the potential for direct contact with the tar
material and miscellaneous solid wastes. Annual ground water monitoring and
environmental use restrictions would be imposed to restrict future water usage.
Treatment of ground water, if deemed necessary, would utilize Hercules existing
water treatment facility. The short-term risks associated with this alternative
would be significantly greater than for Alternative 3, because of the large
quantities of tar to be excavated, staged, and incinerated on site. Potential
risks would be associated with the removal of both residual tar ashes and solid
wastes from the site.
o Compliance with ARARs
Alternative #1 - No Action
This alternative would not comply with the Federal MCLs and NJGWQS, which are
ARARs. The most seriously affected ground water is in the immediate vicinity of
the waste materials. However, detections of constituents in the ground water have
been inconsistent and at low parts per billion (ppb) levels since sampling was
begun. There are no current users of this ground water. Additionally, the NJDEP
soil cleanup criteria, which are "to be considered" (TBCs), would not be met.
Concentrations of pesticides and metals in the surface water in the North .Ditch
currently exceed the Federal Ambient Water Quality Criteria. The only action
specific ARAR which applies to the no action alternative is compliance with the
New Jersey Water Pollution Control Act, which will require a permit for long term
monitoring under O & M.
Alternative #2 - Limited Action
This alternative would not comply with the Federal MCLs and NJGWQS, which are
ARARs. The most seriously affected ground water is in the immediate vicinity of
waste materials. Detections of constituents in the ground water have been
inconsistent and at low ppb levels since sampling was begun. There are no current
users of this ground water. Concentrations of pesticides and metals in the
surface water in the North Ditch currently exceed Federal Ambient Water Quality
Criteria. Additionally the NJDEP soil cleanup criteria, which are TBCs, would not
be met. However, contact with these media would be reduced by site fencing and
restrictions on future land use and well installations. Action specific ARARs
could be complied with and would include obtaining all the permits necessary to
construct the fence and commence with sampling activities associated with o & M.
Alternative #3 - In-Place Containment
This alternative would not meet the Federal MCLs and NJGWQS, which are ARARs. The
most seriously affected ground water is in the immediate vicinity of the waste
materials. Detections of constituents in the ground water have been inconsistent
and at low ppb levels since sampling began. There are no current users of this
ground water. Concentrations of pesticides and metals in the surface water in the
North Ditch exceed current Federal Ambient Water Quality Criteria. Sediments
within the North Ditch exceed NOAA Criteria which are TBCs. Additionally, the
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NJDEP soil cleanup criteria, which are TBCs, would not be met. However, contact
with waste materials would be reduced by site fencing, capping of the waste
materials and tar, and restrictions on future land use and well installations.
Also, filling in the North Ditch with clean imported fill material will preclude
direct contact with sediments. Action specific ARARs would be complied with and
would include obtaining all the permits necessary to implement the remedy and
begin with sampling activitie's associated with O & M.
Location specific ARARs would be satisfied by the imposition of environmental use
restrictions and establishment of a ground water CEA in the vicinity and including
the SWDA.
Alternative #4 - On-Site Incineration and Off-Site Disposal
This alternative would provide compliance with chemical specific ARARs and TBCs.
If all of the tar and the contaminated soil and sediments are removed, the remedy
will meet the cleanup specific ARARs. Ground water ARARs may not be met by
treatment or monitoring, but treatment and/or natural attenuation would reduce
site-related contamination over time. Concentrations of pesticides and metals in
the surface water in the North Ditch exceed current Federal Ambient Water Quality
Criteria. Location and action specific ARARs may be difficult to meet as
extensive work in wetlands and the North Ditch would be required. On-site
incineration permits may not be easily obtained and complete removal of the tar
would be extremely difficult and technically challenging.
o Long-Term Effectiveness and Permanence
Alternative #1 - No Action
This alternative would provide little to no long-term effectiveness and
permanence. All existing risk due to direct contact with the tar/tar soils and
solid waste would remain. This alternative may also increase the potential for
a more serious ground water problem over time. No Action may also increase the
potential for additional, contamination in the North Ditch.
Alternative #2 - Limited Action
This alternative would provide a low to moderate level of long-term effectiveness
and permanence, as the existing risk due to direct contact .with the tar material
would be reduced by restricting access with a perimeter fence, but the potential
for exposure would still exist. The potential -would continue to exist for
degradation of other site media by surface migration of contaminants.
Alternative #3 - In- Place Containment
This alternative would provide a moderate to high level of long-term effectiveness
and permanence as long as the impermeable cap is maintained and the environmental
use restrictions are enforced. The risk due to direct contact with the tar and
the potential for surface migration of the contaminants would be mitigated.
Alternative #4 - On-Site Incineration and Off-Site Disposal
This alternative would provide a high level of long-term effectiveness and
permanence. The risk due to direct contact with the tar and the potential for
surface migration of the constituents would be mitigated. The level of long-term
permanence would be higher for this alternative than that of Alternative 3, as the
tar and solid wastes would be removed from the site. The only potential long-term
concern of tar incineration would stem from the off-site disposal of the incin-
erator ash and the potential liability associated with this disposal.
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o Reduction in Toxicity, Mobility, or Volume
Alternative #1 - No Action
This 'alternative would provide no reduction in the mobility, toxicity and volume
of affected media, as no remedial actions would be performed.
Alternative #2 - Limited Action
This alternative would provide no reduction in the mobility, toxicity and volume
of affected media. The implementation of institutional controls would serve only
to reduce the potential for direct exposure.
Alternative #3 - In-Place Containment
This alternative would provide no reduction in toxicity, or volume of affected
media. However, mobility of contaminants would be reduced due to placement of the
wastes beneath the cap. Placement of an impermeable cap will prevent oozing of
tars/tar sludges through the surface cover when warm temperatures make the tars
more fluid. Without an impermeable membrane, soft tars could theoretically breech
the soil cover and present an exposure hazard. Because the ground water is in
contact with the tar at some locations, the potential for mobility of all constit-
uents into the ground water would not be mitigated. However, there are no current
users of the ground water. The cap will restrict exposure of the waste to
precipitation events and a ground water CEA will be created. Periodic monitoring
will permit assessment of any changes in ground water quality.
Alternative #4 - On-Site Incineration and Off-Site Disposal
This alternative would provide a high level of reduction in mobility, toxicity and
volume of affected media. In particular, this alternative provides reduction in
the toxicity and volume of the tar, as this component is destroyed by incinera-
tion. Placement of the solid waste and residual ash in an off-site landfill would
result in additional volume reduction at the site only.
o Short-Term Effectiveness
Alternative #1 - No Action
This alternative would provide no short term effectiveness. The environmental
impacts would be low as no additional wetlands are disturbed by this alternative.
All current risk levels would remain.
Alternative #2 - Limited Action
This alternative would 'provide moderate short term effectiveness. The
environmental impacts would be limited to wetlands disturbance for fence
construction.
Alternative #3 - In-Place Containment
This alternative would provide a moderate level of short-term effectiveness. A
consolidation and grading of the miscellaneous solid wastes and proper
installation of the cap would increase the potential for exposure to on-site
workers, and to a lesser extent potentially expose off-site communities due to
fugitive dust emissions. Proper health and safety and construction controls could
be readily implemented to mitigate these short-term effects (i.e., dust
suppression and air monitoring). Wetland communities have the potential to be
greatly disturbed in the construction phase of this remedy as almost all of the
construction takes place in wetlands. However, all damages to natural resources
will be mitigated/compensated for.
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Alternative #4 - On-Site Incineration and Off-Site Disposal
This alternative would provide a low level of short-term effectiveness as
excavation of the tar for on-site incineration and consolidation and off-site
disposal of solid waste and residual ash would increase the potential for exposure
to on-site workers and off-site communities due to fugitive dust and organic
emissions. Proper health and safety and construction controls would be required
to mitigate these 'short-term effects. This alternative would result in the
maximum disruption and impact to the wetland areas compared to the other
alternatives due to necessary staging of incineration equipment and materials
associated with these activities. All natural resource damages would be
mitigated/compensated for.
o Implementabilitv '
Alternative #1 - No Action
This alternative would be easily implemented as it requires only periodic
inspections and ground water monitoring.
Alternative #2 - Limited Action
This alternative would be easily implemented as it requires only periodic
inspections, ground water monitoring, environmental use restrictions on land and
ground water, and installation and maintenance of perimeter fencing. This
alternative is both technically and administratively feasible.
Alternative #3 - In-Place Containment
This alternative would have a moderate to high level of implementability. In-
Place Containment is both technically and administratively feasible. The
equipment, labor, and materials required to implement this alternative are readily
available. The subsurface conditions would require proper engineering design and
strict construction quality assurance controls.
Alternative #4 - On-Site Incineration and Off-Site Disposal
This alternative would have a low level of implementability. An extremely high
amount of technical effort is required for excavation, dewatering, on-site
handling, staging, on-site incineration, and off-site disposal of the residual ash
and solid waste. Solid waste and residual ash removal would be. difficult due to
the wetland environment and the engineering properties of the tar. During the
summer the tar becomes softer making it difficult to excavate; pumping would be
virtually impossible since the majority of it is mixed with the underlying
subsurface soils and overlying miscellaneous solid waste. Winter is typically not
favorable for construction due to short working days and extreme weather
conditions.
The tar is solid in the winter, however, as it's manipulated it becomes softer.
Its stability as a hardened solid is questionable. In addition, trial burns and
operational permitting required for the above activities are extensive and
incineration has low acceptability levels in most communities. Off-site
transportation of residual ash would require implementation of optimal trans-
portation routes to minimize the potential exposure to local populations and
compliance with federal and state regulations for transport of hazardous waste.
Alternative #1 - No Action:
This alternative has a relatively low present worth of $201,040. The primary goal
of the No Action Alternative consists of long-term periodic site inspections and
ground water monitoring.
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Alternative #2 - Limited Action:
This alternative has a present worth cost of $478,000. In addition to restricted
access by the installation of perimeter fencing, environmental use restrictions
and engineering controls on future land and ground water use would be imposed.
In addition, semi-annual inspections would be made of the entire SWDA and annual
ground water monitoring would be performed.
Alternative #3 - In-Place Containment:
This alternative has a present worth cost of $1,956,000. The primary components
of this remediation are screening and recycling of lead fragments, consolidation
of the remaining select soils and contaminants under an impermeable cap, semi-
annual inspection of the SWDA, ground water monitoring, and the imposition of
environmental use restrictions and institutional controls on future land and
ground water usage. All damages to natural resource will be mitigated/compensated
for.
Alternative #4 - On-Site Incineration and Off-Site Disposal:
This alternative has a present worth cost of $36,875,000. The primary components
are screening of lead fragments, dewatering, excavation, staging, and on-site
incineration of tar, off-site disposal of residual ash, excavation and off-site
removal of miscellaneous solid wastes. This option would also include semi-annual
inspections of the SWDA, ground water monitoring, and the imposition of environ-
mental use restrictions and engineering controls on future land and ground water
usage. All damages to natural resources will be mitigated/compensated for.
o EPA Acceptance
EPA has reviewed and commented on the proposed plan. While EPA concurrence on
this plan is not a pre-requisite to NJDEP selecting a remedy, every effort has
been made to maintain consistency within and between the agencies. EPA concurred
with NJDEP's selection of In-Place Containment of the solid wastes and tars within
the SWDA. However, EPA did not concur with NJDEP's selection of the No Action
Alternative for the North Ditch. Therefore, NJDEP modified its position with
respect to the North Ditch by selecting the Filling Alternative for the North
Ditch.
o Community Acceptance
Community acceptance assesses the public comments received on the RI/FS Report and
the Proposed Plan.
Community concerns/comments received during the public comment period and public
meeting held on August 10, 1994 are included in the responsiveness summary, which
is part of this ROD. Community concerns/comments received indicate that the
community accepts the preferred alternative identified in the Proposed Plan and
identified in the ROD herein.
9. SELECTED REMEDY
Based upon an evaluation of the various alternatives and after consideration of
public comments, NJDEP has determined that a Modified Alternative #3 (In-Place
Containment) is the appropriate remedy for the SWDA operable unit of the Hercules
Incorporated, Higgins Plant Superfund site because it best satisfies the
requirements of CERCLA and the NCP's nine evaluation criteria for the remedial
alternatives.
The modification to Alternative #3 concerns remedial activities in the North •
Ditch. The Department has chosen to modify the remedy indicated in the proposed
plan by including the Filling Alternative for the North Ditch. This would
eliminate any potential ecological risks associated with direct contact with
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contaminated sediments. All damages to wetlands through implementation of this
remedy will be mitigated/compensated for.
Ground water monitoring will be conducted to evaluate ground water quality.
Consolidation of the tar and miscellaneous solid wastes under an impermeable cap
will eliminate direct contact with the hazardous constituents within the SWDA and
is protective of human health and the environment. Collection and recycling of
lead fragments from the area will reduce concentrations of this contaminant from
the SWDA. Fencing and storm water controls will protect the integrity of the cap.
Fencing will also increase the protectiveness of the remedy by limiting access to
the area. The designation of the CEA will eliminate ground water use in and
around the vicinity of the SWDA.
The selected alternative achieves the ARARs more quickly, or as quickly as the
other options. The selected alternative will provide the best balance of trade-
offs among alternatives with respect to the evaluating criteria. NJDEP believes
that the selected alternative will be protective of human health and the envi-
ronment, will comply with ARARs, employs resource recovery technologies and will
be cost effective to the maximum extent practicable.
The total costs for Alternatives #1, #2, #3, and #4 are $201,040, $478,000,
$2,320,312 and $36,875,000, respectively. Alternative #3, In-Place Containment
is a non-permanent remedy that originally had an associated cost of $1,956,000 but
as modified now has a cost of $2,320,312. Alternative #4, On-Site Incineration
and Off-Site Disposal, is the only permanent remedy available for the tar with an
associated cost of $36,875,000. Alternative #3 is the option of choice.
Since the SWDA would not be effectively excavated and treated due its large size
and the absence of hot-spots representing major sources of ground water contamina-
tion, none of the implementable alternatives considered satisfied the statutory
preference for treatment as a principal element of the remedy with respect to
source control.
10. STATUTORY DETERMINATIONS
Under their legal authorities, NJDEP's and EPA's primary responsibility at
Superfund sites is to undertake remedial actions that achieve adequate protection
of human health and the environment. In addition, section 121 of CERCLA
establishes several other statutory requirements and preferences. These specify
that when complete, the selected remedial action for this site must comply with
applicable or relevant and appropriate environmental standards established under
State and Federal environmental laws unless a statutory waiver is justified. The
selected remedy also must be cost effective and utilize permanent solutions and
alternative treatment technologies to the maximum extent practicable. Finally, the
statute includes a preference for remedies that employ treatment that permanently
and significantly reduce the volume, toxicity, or mobility of hazardous wastes as
their principal element.
The selected remedy is protective of human health and the environment, complies
with State and Federal requirements that are legally applicable or relevant and
appropriate requirements for the remedial action and is cost effective. This
remedy utilizes permanent solutions and alternate treatment technologies to the
maximum extent practicable for this site. This remedy will require the institution
of a CEA. Because this remedy includes leaving hazardous substances on-site, a
review will be conducted every five (5) years after commencement of the remedial
action to ensure the remedy continues to provided adequate protection of human
health and the environment.
The selected remedy will not meet Federal MCLs and NJGWQS, which are ARARS.
However, the most seriously affected, ground water in the immediate vicinity of
the SWDA, has exhibited low levels since the onset of sampling. Additionally,
there are no current users of. ground water. Concentrations of pesticides and
metals in the surface water of the North Ditch exceed current Federal Ambient
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Water Quality Criteria. Sediments within the North Ditch exceed NOAA Criteria
which are TBCs. Finally, NJSCC, which are TBC's would not be met. However,
contact with waste materials would be reduced by site fencing, capping of the
waste materials, filling in the North Ditch, and restrictions on future land use
and well restrictions.
Action specific ARARS will be achieved at a significantly lower cost and with
minimal disturbance to the surrounding neighbors and community than the other
options. The selected alternative will provide the best balance of trade-offs
among all the alternatives with respect to the CERCLA nine criteria. NJDEP has
selected a modified In-Place Containment as the remedial alternative because it
will comply with ARARs to the maximum extent practicable, will utilize permanent
solutions and alternative treatment technologies to the maximum extent
practicable, will be cost effective, and will create a minimal disturbance to the
surrounding community during the remediation process.
11. DOCUMENTATION OF SIGNIFICANT CHANGES
NJDEP had indicated during the public meeting held on August 10, 1994 that No
Action had been selected for the North Ditch. The North Ditch was addressed in
the Feasibility Study, but a specific alternative analysis was not performed in
the Proposed Plan.
As discussed in Section 9. above, EPA concurs with In-Place Containment of the
solid wastes and tars within the SWDA. However, EPA did not concur with NJDEP's
selection of the No Action Alternative for the North Ditch. The EPA's stated
position is that No Action for the North Ditch may not provide for adequate
protection of wildlife and the environment. The Department reevaluated EPA's
concern regarding a No Action alternative for the North Ditch. Upon completion
of this evaluation, the modification, as discussed in the Feasibility Study, was
added to Alternative #3 (See # 9 above, SELECTED REMEDY).
GLOSSARY
This glossary defines the technical terms used in this Record of Decision. The
terms and abbreviations contained in this glossary are often defined in the
context of hazardous waste management, and apply specifically to work performed
under the Superfund program. Therefore, these terms may have other meanings when
used in a different context.
Administrative Consent Order: A legal and enforceable agreement between EPA or
the State and the potentially responsible parties (PRPs). Under the terms of the
Order, the PRPs agree to perform or pay for site studies or cleanup work. It also
describes the oversight rules, responsibilities and enforcement options that the
state government may exercise in the event of non-compliance by the PRPs. This
Order is signed by the PRPs and the state government; it does not require approval
by a judge. The federal equivalent of the Administrative Consent Order is the
Administrative Order or Consent.
Aquifer: An underground layer of rock, sand, or gravel capable of storing water
within cracks and pore spaces, or between grains. When water contained within an
aquifer is of ' sufficient quantity and quality, it can be tapped and used for
drinking or other purposes. The water contained in the aquifer is called ground
water.
ARAR: An acronym for "Applicable or Relevant and Appropriate Requirements".
ARARs may be chemical, location, or action specific and include federal standards
and more stringent state standards that are legally applicable or relevant and
appropriate under the circumstances.
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Backfill: To refill an excavated area with removed earth; or the material itself
that is used to refill an excavated area.
Cap: A layer of material, such as clay or a synthetic material, used to prevent
precipitation from penetrating and spreading contaminated materials. The surface
of the cap is generally mounded or sloped so water will drain off.
CERCLA: (Comprehensive Environmental Response, Compensation, and Liability Act
of 1980) A Federal law passed in 1980 and modified in 1986 by the Superfund
Amendments and Re-authorization Act (SARA). The Act created a special tax to fund
a Trust Fund, commonly known as the Superfund, to investigate and remediate aban-
doned or uncontrolled hazardous waste sites. Under the program, EPA can either:
1) pay for site remediation when parties responsible for the contamination cannot
be located -or are un-willing or unable to perform the work; or
2) take legal action to force parties responsible for site contamination to
remediate the site or pay back the Federal government for the cost of the
remediation.
Classification Exception Area (CEA): These are areas which may be established by
the NJDEP only when the NJDEP determines that constituent standards for a given
classification are not being met, will not be met for a period of time, or cannot
be met for a period of time in a localized area due to: natural quality;
localized effects of a discharge approved through a NJPDES permit action; pollu-
tion caused by human activity within a contaminated site as defined by the NJDEP
in the context of an applicable regulatory program (for example, Site Remediation
Program Oversight Document).
Containment: The process of enclosing or containing hazardous substances in a
structure, typically in ponds and lagoons, to prevent the migration of
contaminants into the environment.
Dewater: To remove water from wastes, soils, or chemicals.
Downgradient/Downslope: A downward hydrologic slope that causes ground water to
move toward lower elevations. Therefore, wells downgradient of a contaminated
ground water source are prone to receiving pollutants.
Engineering Control: Any mechanism to contain or stabilize contamination or
ensure the effectiveness of a remedial action. Engineering controls may include,
without limitation, caps, covers, dikes, trenches, leachate collection systems,
signs, fences and access controls.
Ground Water Table: The level in the saturated zone at which the hydraulic
pressure is equal to the atmospheric pressure. This level is best located by the
use of piezometers or monitoring wells.
Impermeable: A layer of natural and/or man-made material of sufficient thickness,
density and composition so as to have the maximum permeability for water of 10
cm/sec at the maximum anticipated hydrostatic pressure, not permitting fluids to
pass through it (i.e., an impermeable cap).
Incineration: A treatment technology involving the burning of certain types of
solid, liquid, or gaseous materials under controlled conditions to destroy or
reduce the volume of hazardous waste.
In-situ: To leave in its original place.
Leachate: A contaminated liquid resulting when water percolates, or trickles,
through waste materials and collects components of those wastes.
Levee: An embankment built alongside a river to prevent high water from flooding
bordering land.
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MCLs: An acronym for Maximum Contaminant Level. The maximum permissible level
of a contaminant in water delivered to any user of a public water system.
Micrograms per kilogram (ug/kg); Milligrams per liter (mg/L): Units commonly
used to express concentrations of contaminants.
Monitoring Wells: Special wells drilled at specific locations on or off a
hazardous disposal site where ground water can be sampled at selected depths and
studied to determine the direction of ground water flow and types and amounts of
contaminants present.
NJGWQS: An acronym for New Jersey Ground Water Quality Standards N.J.A.C. 7:9-6
adopted January 7, 1993 which became effective February 1, 1993. These standards
are used as regulatory requirements to govern and protect ground water quality in
the State of New Jersey.
NOAA: An acronym for the National Oceanic Atmospheric Administration.
O & M: An acronym for operation and maintenance activities conducted at a site,
after a Superfund action is completed, to ensure that the remedy is effective and
operating properly.
Parts per billion (ppb); parts per million (ppm); Units commonly used to express
concentrations of contaminants.
Receptor: Any human or other ecological component which is or may be affected by
a contaminant from a contaminated site.
Remedial Investigation/ Feasibility Study (RI/FS): Investigation and analytical
studies usually performed at the same time in an interactive, iterative process,
and together referred to as the "RI/FS". They are intended to:
1) gather the data necessary to determine the type and extent of contamination at
a Superfund site;
2) establish criteria for remediating the site;
3) identify and screen remediation alternatives for remedial action; and
4) analyze in detail the technology and costs of the alternatives.
Surface Water Quality Standards: State-adopted and EPA-approved ambient standards
for surface water bodies. The standards cover the use of the water body and the
water quality criteria that must be met to protect the designated use or users.
TCLP: An acronym used for the Toxicity Characteristic Leaching Procedure.
Terrestrial Wildlife: Those species which primarily use and inhabit "the land"
(i.e. herbivores which grass on vegetated fields, carnivores which feed on
herbivores and each other, and decomposers which feed on the dead plant and animal
material and return nutrients to the soil for recycling).
Time to Implement: The amount of time it takes to obtain the necessary equipment,
services, and materials to install, operate and maintain the selected remedial
alternative. This includes all activities required to coordinate with federal,
state and local regulatory agencies, and to obtain necessary approvals and/or
permits.
Upgradient; Upslope: Upstream; an upward slope. Demarks areas that^are higher
than contaminated areas and, therefore, are not prone to contamination by the
movement of polluted ground water.
Use Restriction: A form of institutional control in which a notice is filed with
the office of the county recording officer, in the county in which the property
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is located. Its intent is to inform prospective holders of an interest in the
property that contamination exists on the property at a level that may statutorily
restrict certain uses of or access to all or part of that property. It will also
contain a delineation of those restrictions, a description of all specific
engineering or institutional controls at the property that exist and that shall
be maintained in order to prevent exposure to contaminants remaining on the
property, and the written consent on the notice by the owner of the property. Use
restrictions are filed as DECLARATION OF ENVIRONMENTAL RESTRICTIONS.
Volatile Organic Compounds (VOCs): VOCs are made as secondary petrochemicals.
They include but are not limited to, light alcohols, acetone, trichloroethylene,
perchloroethylene, dichloroethylene, benzene, vinyl chloride, toluene, and
methylene chloride. These potentially toxic chemicals can be used as solvents,
degreasers, paints, thinners, and fuels. Because of their volatile nature, they
readily evaporate into the air, increasing the potential exposure to humans. Due
to their low water solubility, environmental persistence, and wide spread
industrial use, they are commonly found in soil and ground water.
Wetland: An area that is regularly saturated by surface or ground water and,
under normal circumstances, capable of supporting vegetation typically adapted for
life in saturated soil conditions. Wetlands are critical to sustaining many
species of fish and wildlife. Wetlands generally include swamps, marshes, and
bogs. Wetlands may be either coastal or inland. Coastal wetlands have salt or
brackish (a mixture of salt and fresh) water, and most have tides, while inland
wetlands are non-tidal and freshwater. Coastal wetlands are an integral component
.of estuaries.
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RESPONSIVENESS SUMMARY
Responsiveness Summary for the Hercules, Inc.
Solid Waste Disposal Area Record of Decision
Overview
This is a summary of the public's questions and comments regarding the Proposed
Plan for capping the Solid Waste Disposal Area at the Hercules, Inc. Superfund
Site in Gibbstown, Gloucester County under Superfund guidelines, and the New
Jersey Department of Environmental Protection's (Department) responses to those
comments.
The public comment period extended from July 27, 1994 through August 25, 1994 and
provided interested parties the opportunity to comment on the Proposed Plan for
the Hercules, Inc. Superfund Site. On August 10, 1994 at 7:00 p.m., during the
comment period, the Department held a public meeting at the Gibbstown Fire Hall
to discuss the reports and the preferred remedy.
On the basis of the information contained in Remedial Investigation Reports, the
Department recommended capping the Solid Waste Disposal Area (SWDA) with a
flexible, impermeable cap, fencing the SWDA, and monitoring the ground water.
Background on Community Involvement and Concerns
The Hercules, Inc. Superfund Site is an active chemical production facility
located adjacent to the Delaware River in Gibbstown, Gloucester County. The site
came to the attention of the Department in 1981 when benzene was detected in the
ground water at the plant. In 1982 the site was listed on the National
Priorities (Superfund) List due to the benzene detected in the ground water
beneath the production plant and also the presence of tar pits and solid waste
in the part of the site known as the Solid Waste Disposal Area (SWDA). A formal
Remedial Investigation of the ground water, surface water, sediments, soil and
air at the production plant was initiated in 1986 and is ongoing. The SWDA was
addressed separately from the remainder of the plant because it was determined
to be unrelated to the other areas of environmental concern.
The SWDA of the Hercules site is located in a low lying swampy area next to the
river which is isolated from the production plant. It covers approximately four
acres and consists of two visible tar disposal areas, or "pits", and debris
deposited between and immediately adjacent to the tar pits. The tars were a
waste product generated by the production of aniline and were deposited at the
SWDA prior to 1952 by the Du Pont Corporation, the previous owner of that portion
of the Hercules site. Hercules obtained the property that comprises the SWDA
from DuPont in 1952, and until 1974 used the area to dispose of solid waste
materials from manufacturing processes and inert construction debris. Hercules
stopped disposing of waste in the SWDA in 1974. From 1987 to 1993, Hercules
conducted a Remedial Investigation of the SWDA. The results of the study and the
Department's proposal to address the SWDA were the subject of a public meeting
which was held in August 1994, which was attended by approximately 35 people.
Community involvement and interest in this site has historically been low.
Representatives from Hercules periodically hold meetings with local officials on
the general status of the site. The SWDA in particular has not elicited much
interest from the local residents. This is most likely due to the location and
low visibility of the SWDA, which is remote and difficult to reach, both by foot
and by vehicle. Trespassing onto the SWDA has not been a significant problem,
according to representatives from Hercules.
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Summary of Comments Received During the
Public Comment Period and Department Responses
Concerns raised during the Hercules, Inc. Superfund Site SWDA Public Meeting held
on August 10, 1994 and during the comment period from July 27 to August 25, 1994
are summarized below. The comments are grouped in the following categories:
1. Protectiveness of the Preferred Remedy
2. Responsibility for SWDA
3. Cap Specifics/Impermeable Liner Requirement
4. Risk Assessment -
5. General Statements
QUESTIONS AND COMMENTS
PROTECTIVENESS OP THE PREFERRED REMEDY
Question: How high will the fence around the SWDA be if the preferred remedy is
implemented? What if a child climbs the fence and gets into the SWDA?
Response: The height of the fence will be determined during the design phase.
The fence will be high enough to keep people out, and the fence and the area
around it will be periodically inspected to ensure the SWDA remains secure. If
someone were to breach the fence, the capping material would prevent direct
contact with the buried waste.
Question: The map included with the Proposed Plan shows two levees at the SWDA,
one on the river side and one on the southern side. Wouldn't the contaminated
material be able to get out on the other three sides of the SWDA?
Response: There are earthen levees on the southern and the northwestern sides
of the SWDA. The levees are earthen material and some solid waste material that
have formed natural slopes. On the other sides of the SWDA where there are no
levees, the tar material, which has been in place since the 1950s' through the
1970s, has reached a point of equilibrium. It will not move any farther than it
already has moved at this time. In fact, the tar material has been in its
current configuration since the 1970s, based on a review of all the aerial
photographs and the Department's observations of the site. Furthermore, it must
be emphasized that upon completion of the remedial actions all of the tar
materials and other solid waste will be contained within a cap or cover.
Question: If the river wall broke and the area flooded, wouldn't the material
at the SWDA become dispersed throughout the town?
Response: The cap will be designed to protect against a 100-year storm event.
However, if the cap does fail, the tar would not mix with water and it would be
unlikely that the tar would move due to its shape and size.
Question: Will the SWDA have a lid put on it?
Response: The preferred remedy to cap the area essentially amounts to the
placement of a lid over the waste.
Question: Will water be able to penetrate the cap?
Response: The cap would include an impermeable liner to prohibit infiltration
of water through the buried waste.
Question: A liner was put in the ground out west that was guaranteed to last a
hundred years and within the first year it broke. Could this happen with the
proposed cap?
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Response: Hercules will be required to conduct periodic inspections and to
maintain the cap to ensure its continued effectiveness. Should the cap break,
Hercules will be required to conduct any necessary repairs. However, it is
unlikely the cap .will break.
Question: What if the SWDA caught fire?
Response: The preferred remedy when completed would consist of a flexible
impermeable cap covering the tar and solid waste material, which would be covered
by a layer of clean, vegetated soil and enclosed with a fence. There is no
reason to believe that the SWDA would catch fire.
Question: If the ground over the SWDA is vegetated as part of the capping,
wouldn't contaminants be drawn up through the vegetation, and then be consumed
by wildlife?
Response: No. Under the preferred remedy, an impermeable cap will be placed
over the tars and solid waste material. Clean soil will then be introduced on
top of the impermeable liner, and the area vegetated. The contaminated material
will not be in contact the clean soil.
Question: The Proposed Plan states that the preferred remedy would provide a
high level of protection of human health and the environment. What is the
definition of "a high level of protection"?
Response: A remedy that provides a high level of protection is one that would
meet the one-in-a-million cancer risk standard, and has a Hazard Index of less
than 1.0 for non-carcinogenic (non-cancer) health effects. A remedy that meets
this level of protectiveness would not result in more than one additional cancer
per one million people exposed to the remediated site over a 70 year period (a
typical lifetime), and would not present a risk for non-cancerous health effects
in humans.
Question: Will the SWDA part of the Hercules site be taken off the Superfund
list after the five year review period? What kind of monitoring will take place
after the five year period is over?
Response: As long as there are contaminants in place, the site will stay on the
Superfund list and the effectiveness of the remedy will be reviewed every five
years. Ground water at the SWDA will be monitored for 30 years.
Question: Why was capping of the SWDA chosen as the preferred remedy if the
incineration alternative', while initially more expensive, may turn out to be the
cheaper alternative in the long term if problems were to develop with the cap?
Response: The cost estimates provided in the Proposed Plan are the costs for
implementing the remedies and monitoring the SWDA over a thirty year time period.
Whether or not the incineration remedy would prove to be more expensive than the
capping remedy over the long term cannot be determined with absolute certainty.
However, the Department is responsible for providing a high level of protect-
iveness while at the same time following the state federal laws which require
that factors such as the cost, permanence, and the long effectiveness versus the
short-term impacts of the remedies be considered. The community's acceptance of
a remedy is also a consideration, and it is .unlikely that the community would
accept an incinerator in the town. The Department believes that the capping of
the SWDA provides the best balance of these factors of all the remedial options.
Question: If after 30 years there appears to be no spread of the contamination,
will the SWDA portion of the Hercules site be taken off of the Super-fiind list?
Response: As long as contamination remains at the SWDA, which it will under the
capping remedy, then the site will remain on the Superfund list.
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Question: What is the difference between completion of a 30 year monitoring plan
and the removal of a site from the Superfund List?
Response: The ground water at the SWDA will be sampled for at least 30 years
under the preferred remedy. After that, more ground water sampling may or may
not be done, based upon the results of that sampling. However, the institutional
controls imposed under the preferred remedy in the form of environmental use
restrictions or deed notices would require that the remedy be maintained and the
SWDA secured beyond that 30 year period. As stated previously, the site will
remain on the Superfund List as long as there are contaminants remaining on the
site.
Question: How often would ground water be sampled under the 30 year monitoring
plan? What criteria will be used to evaluate the sampling results?
Response: While the specific sampling frequency has not been determined, it is
anticipated that the ground water will be sampled on at least an annual basis.
The ground water sampling results will be compared to the New Jersey Ground Water
Quality Standards. The sampling results, including ground water flow direction,
will be evaluated to determine the effectiveness of the capping remedy and
protection of potential receptors.
Question: Is any ground water monitoring done outside the Hercules plant within
the town?
Response: There are ground water monitoring wells outside the Hercules property
that Hercules samples regularly and submits the data to the Department.
Additionally, Gibbstown's water is sampled regularly pursuant to the New Jersey
Safe Drinking Water Act, which requires all public community water systems to be
tested periodically for hazardous constituents.
Question: The Proposed Plan states that the In-Place Containment (capping) is
a non-permanent remedy with a cost of S2.0 million and that the Incineration with
Off-Site Disposal is the only permanent remedy and has a cost of $36 million.
It goes on to state that the cost differential between these two alternatives .is
greater than 50 percent of the non-permanent remedy, and therefore the In-Place
Containment is the option of choice. Does this mean that cost was the deter-
mining factor? Should cost be the determining factor if were are seeking a
permanent resolution to this problem?
Response: Under the Comprehensive Environmental Response, Compensation and
Liability Act (CERCLA), remedial alternatives for a Superfund site must be
evaluated for several criteria. The first and most important consideration is
whether a remedial alternative is protective of human health, safety and the
environment. If two or more remedial alternatives are determined to meet the
protectiveness requirement, then the alternatives must be weighed against each
other based upon the following eight criteria: 1) compliance with other statutory
laws; 2) long-term effectiveness and permanence; 3) reduction of toxicity,
mobility or volume through treatment; 4) short-term effectiveness; .5)
implementability; 6) cost; 7) acceptance by the United States Environmental
Protection Agency (USEPA); and 8) acceptance by the community.
Analysis of the In-Place Containment (capping) remedy and the Incineration remedy
indicated that both alternatives were protective of human health and the
environment. The In-Place Containment remedy, however, was determined to
represent the best overall balance of the eight remaining criteria under CERCLA.
Comment: The Proposed Plan states that the SWDA could not be cost-effectively
excavated due to its large size. However, BROS Landfill in Logan Towns&ip, three
miles from Gibbstown, is a much larger site that is being permanently cleaned up
through excavation and other methods. This discrepancy disturbs me.
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Response: The cost-effectiveness of a permanent remedy at a site is an
evaluation that is. made relative to the hazards that the site presents. There
is considerable difference between the Hercules SWDA and the BROS Landfill. High
levels of polychlorinated biphenyls (PCBs) were detected at the BROS site, and
the cancer risk b.ased upon exposure to the PCBs was much more severe than the
cancer risk that was determined based on the Risk Assessment for the SWDA at the
Hercules site. In addition, the contamination at BROS was determined to be
likely to migrate from the site, as opposed to the Hercules SWDA in which the
contamination is relatively immobile. Finally, the ground water and the wetlands
at the BROS site were found to be much more highly contaminated than at the SWDA.
In all, the magnitude of the contamination at the SWDA was fairly low, and this
was a factor which contributed to the recommendation of the nonpermanent remedy
of In-Place Containment (capping).
Question: How many ground water monitor wells have been installed at the SWDA
since 1985? Why were these additional wells installed? Are there plans to
install additional ground water monitoring wells?
Response: Six additional ground water monitoring wells were installed since
1985, for a total of 11 monitoring wells surrounding the SWDA. The additional
wells were installed to evaluate the area of ground water contamination and to
determine the ground water flow direction. At this time there are no plans to
install additional ground water monitoring wells, however wells may be added in
the future if sampling data indicates they are needed.
Question: What safety precautions will be arranged if the Department proceeds
with Alternative 3 (In-Place Containment) or Alternative 4 (Incineration and
Off-Site Disposal) as far as warnings to notify the Township or the residents if
something goes wrong?
Response: During the construction of the In-Place Containment remedy, Hercules'
contractor will be required to have approved site safety plans which would
specify measures, including notification of officials, to be taken in the event
that an emergency arises. Once the In-Place Containment Remedy has been
completed, it is unlikely that anything will go wrong because it is a proven
remediation technology. Any unexpected changes in soil or ground water quality
would be detected by. the required periodic inspections of the cap and sampling
of the monitoring wells. In the event of any imminent hazard, Hercules and/or
the Department would immediately notify the local officials, who would contact
the local residents.
Question: Would the local officials be able to respond quickly if something were
to occur of catastrophic nature?
Response: Based on the Department's studies there is nothing in the SWDA that
would leave the site or migrate from the site rapidly. There are no gases being
generated at the SWDA. Once the solid material is capped or contained, the only
place that contamination may potentially go would be into the ground water. Any
change to the ground water would be detected by the Department during the routine
sampling of the monitoring wells surrounding the contained waste, which will
effectively prevent any threat to the community.
Question: Has the tar moved within the last 30 years?
Response: The tar has moved a little bit since it was placed at the SWDA. The
movement of the tar is due to the fact that the tar has different physical
property depending on the temperature. It has a hard, glassy surface in the
winter and in the summer it is soft. With the change in temperatures over the
seasons from the time that the tar was placed there, it has moved a little.
Since there hasn't been any more material placed there recently, the tar'will not
move any further.
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Question: As shown in Figure 1 (Location map), floodgates are situated oh
Clonmell Creek and adjacent to the SWDA. Has the Department or Hercules, Inc.
determined the physical conditions of improvements needed for these structures,
and their ability to protect the plant and surrounding area from flooding? Also,
is the SWDA cap capable of withstanding a major flooding event?
Response: The conditions of the floodgates and the ability of the cap to
withstand flooding events will be addressed during the design of the SWDA cap.
The existing levee along the Delaware River provides some protection against
flooding of the SWDA. In addition, storm water management controls will be a
primary component of the final engineered cap system.
Question: The report mentions a ten foot high fence constructed by the Army Corp
of Engineers to separate the Hercules property from the Delaware River. Does the
ACOE schedule regular inspections to determine the levee's structural integrity
and its ability to protect the area from flooding?
Response: The ACOE did not construct the Delaware River levee and does not
conduct inspections. Hercules will maintain responsibility for portion of the
levee which abuts their prpoerty.
RESPONSIBILITY FOR THE SOLID HASTE DISPOSAL AREA
Question: If someone gets into the SWDA, who's responsible?
Response: Hercules is responsible for the SWDA, and will retain responsibility
for it as long as contamination remains there.
Question: Who is responsible for the SWDA after the five year review period has
elapsed?
Response: The five year review evaluates the protectiveness of the capping
remedy. If the Department determines that the capping remedy is not protective
of the environment, Hercules will be required to take additional action to ensure
protectiveness. Hercules will retain responsibility for the SWDA as long as
contamination remains there.
Question: What would happen if Hercules, Inc. were to sell the property before
the thirty year ground water monitoring period is over? Will the buyer of the
property have to continue monitoring the ground water?
Response: The preferred remedy includes a requirement for institutional controls
at the SWDA. The institutional controls would be in the form of a "Declaration
of Environmental Restrictions" (DER), which is a notice in the deed file. The
DER would require a potential purchaser of the property to maintain the
conditions at the SWDA, including the 30 year ground water monitoring program.
Hercules, Inc. would retain liability for the contamination, however, in the
event that the property were sold.
Question: Who would take over responsibility and liability for the SWDA in the
event that Hercules were to go bankrupt, and go out of business? Who would pay
the cost for maintaining and monitoring the site?
Response: The Department and the United States Environmental Protection Agency
would share responsibility and liability for the site if Hercules were to go
bankrupt. Public funds would pay for the cost of maintaining and monitoring the
site.
Question: Did Hercules purchase the property knowing that it was contaminated?
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Response: Based on the Department's discussions with plant employees familiar
with the historical operations, Hercules was probably aware that solid waste
materials were placed in the area now known as the SWDA prior to their purchase
of the property in 1952. However, the material was most likely not considered
"contaminated" at" that time.
Question: Is the Administrative Consent Order for the Hercules site still in
effect? If so, when will it expire?
Response: The Administrative Consent Order is in effect, and will continue to
be in effect until the investigation of the main plant is completed.
Question: Is the $2 million letter of credit still in effect, or has it been
reduced?
Response: The $2 million letter of credit is still in effect, though Hercules
may change its form if it so chooses.
Question: If Hercules wanted to reduce the letter of credit to a smaller amount,
would the Department have to agree to that reduction first?
Response: Yes. The letter of credit must at least cover the cost of the
cleanup, so in fact the Department could increase it if it was determined that
more money is needed to complete the cleanup.
CAP SPECIFICS/IMPERMEABLE LINER REQUIREMENT
Comment: Hercules agrees that containment of waste materials, collection and
recycling of lead fragments, ground water monitoring, institutional controls, and
designation of a Classification Exception Area for ground water underneath and
surrounding the SWDA. Hercules, Inc. also concurs with the finding stated in the
Proposed Plan that the most serious risk from the SWDA is direct exposure of
hazardous substances to a transient population of wildlife and the occasional
plant employee or trespasser. Based on this finding Hercules, Inc. agrees that
a cover system is needed to prevent direct contact with the tar and miscellaneous
solid waste debris.
DuPont, an adjacent property owner, supports the general concept of containment
in place for the SWDA. With the cover in place, no risk will be present because
direct exposure to the waste is eliminated. In addition, the ground water does
not present an unacceptable risk. Excavation, treatment, and off-site disposal
(Alternative 4) are unnecessarily costly in light of the equally protective yet
more feasible solution of containing the waste on-site. Containment eliminates
the short term risk created by implementation of Alternative 4.
The Hercules Gibbstown SWDA has been under investigation for many years.
Clearly, the SWDA should be closed (with a soil cover or other type of cap) as
would be required of any SWDA. Although DuPont has concerns about the
methodologies and assumptions used in the risk assessment and believes that it
significantly overstates the risk, once covered the SWDA will pose no significant
risk to human health and the environment. Rather than continuing to study the
SWDA, DuPont supports the Department's plan to move forward and implement the
in-place containment remedial action.
Response: The Department agrees that in-place containment provides the best
balance of a cost-effective remedy that reduces both short-term and long-term
exposures to the wastes.
Comment: Hercules, Inc. disagrees with the need to eliminate the exposure of
solid waste to precipitation events, as stated on page 8 of the Proposed Plan.
During the course of the Remedial Investigation, Risk Assessment and Feasibility
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Study, it was never determined that leaching of the solid waste was a migration
pathway requiring remediation. The data collected at the SWDA has not
demonstrated a need to eliminate or prevent infiltration of the solid waste.
Infiltration of precipitation through the solid waste/tar has not been identified
as an exposure pathway requiring remediation. The solid waste/tar has been in
place since the late 1950s and there has been no long term degradation of ground
water quality. Restricting infiltration will not improve the present or future
ground water quality. Since there presently is no requirement to mitigate the
infiltration pathway (because there is no associated risk), Hercules, Inc.
believes the requirement for an impermeable cap is not technically justifiable.
The proposed "impermeable" cap required in the Proposed Plan is a rigid
regulatory requirement, that is not necessary given the Remedial Action
Objectives to mitigate the direct contact with the tar material, and
miscellaneous solid waste. The in-place containment system is focused on
reducing the direct contact pathway. To meet this requirement the capping system
in the Feasibility Study was focused on strength and long-term integrity.
Regarding the need to "eliminate the exposure of the solid waste to precipitation
events", the promotion of surface water runoff is part of any capping system, due
to surface drainage requirements for an engineered capping system.
In general, regrading and recontouring the surface of an area will promote
positive surface water flow, and significantly reduce infiltration of
precipitation. The reinforced soil cap proposed in the Feasibility Study will
require regrading and recontouring of the land surface now encompassing the SWDA.
Upon completion of the new capping system, new vegetative cover will promote
evapotranspiration of non-runoff water, providing additional reduction of water
available to infiltrate the cap system. In addition, the materials used to
construct the reinforced soil cap, along with the proposed regraded slope and
vegetative cover, will further limit the amount of infiltration of precipitation
and promote runoff.
The Department's technical committee comments on the Feasibility Study indicated
that the reinforced soil capping system construction materials are best
determined in the Remedial Design Phase. By restricting the cap to include an
impermeable component, Hercules believes that the Proposed Plan is inconsistent
with the Feasibility Study, and the technical committee's recommendations and
requirements. The Proposed Plan does not provide the flexibility required to
create the most technically sound, cost-effective engineered cap system which
meets the requirements of the technical committee.
In summary, an impermeable cap does not increase the reduction in risk as
compared' to a reinforced soil cap. A reinforced soil cap will mitigate the
direct contact exposure pathway, prevent migration via surface runoff, and
engineered properly it will also promote surface water runoff. Hercules, Inc.
therefore requests that the Department provide technical justification for an
impermeable liner component for the containment remedy in the Proposed Plan.
Comment: The Proposed Plan does not clearly provide the basis for requiring an
impermeable cap. The Remedial Investigation and Feasibility Study (RI/FS) show,
as stated on page 3 of the Proposed Plan, that "the tar constituents are
essentially insoluble, and the tar is relatively impermeable. This limits the
leaching capacity of the tar." Based on the study conclusions and the lack of
an impact on ground water from the tar, it is DuPont' s opinion that an
impermeable cap is not necessary.
The Feasibility Study recommended containment in place (Alternative 3),
consisting of a vegetated soil cover with a geosynthetic reinforcement layer.
However, on page 6 of the Proposed Plan, under description of Alternative 3, and
impermeable liner cap is specified at an additional estimated cost of
approximately $300,000.
31
-------
Later in the document (page 8 under Alternative 3 discussion), the Department
appears to be concerned with the potential for future leaching of the solid waste
materials overlying the tar. Based on Du Font's review of the data, the
low-level constituent concentrations detected in the ground water appear to be
related to the salid waste materials. For example, the highest concentratipns
in the ground water are the compounds cumene and toluene,, which were found to be
related to the solid waste.
It is Du Font's understanding that the rationale for the impermeable cap is to
prevent surface infiltration from causing leaching of the solid waste. The
Record of Decision should clearly reflect the basis for specifying an impermeable
cap to justify the additional expense as the current rational is not explicit.
Further, Du Pont supports the Feasibility Study recommendation that a reinforced
cover is an appropriate remedy.
Response: The Department believes it is justified in requiring an impermeable
liner as a component of the reinforced soil cap. The requirement for an
impermeable cap is based on the results of the Risk Assessment, and while direct
contact with the tars at the SWDA was identified as the primary risk in the Risk
Assessment, extensive investigations of the area identified other characteristics
of the SWDA that must be addressed by this action.
The impermeable cap is being required to prevent leachate generation from the
various solid wastes mixed with the tar. Additionally, the impermeable cap is
considered relevant and appropriate for the SWDA since the aniline still bottom
tars are a listed hazardous waste and this action- is essentially a closure of a
landfill known to contain a large quantity of hazardous waste. While the
Department recognizes and emphasizes that the tars are "largely insoluble" and
thus leaching will be "limited", the fact remains that the tar does slowly leach
contaminants to the surrounding environment. The tar samples did leach benzidine
in a TCLP (Toxicity Characteristic Leaching Procedure) test performed in 1988.
In addition, several constituents (i.e., lead, chromium, semi-volatile compounds,
tentatively identified compounds, etc.) found in the tar sample analysis were
also found in the ground water, underlying soils, and .surrounding surface waters.
Some of these constituents were detected at concentrations exceeding ground water
standards on multiple occasions. Based on the concentrations of lead detected
in the analysis of the tar, the Department cannot be certain that the levels of
lead detected in the ground water can be attributed only to the presence of lead
fragments found in the area. During the excavation of test pits through the
buried tars and solid wastes, a variety of materials were found above the water
table that could potentially.leach contaminants. The materials found included
drums, black ashy material, soft tars and black oily materials (possibly tar
sludges). These findings suggest the possibility that the tars are present in
varying states and degrees of solubility below the surface. Furthermore, during
implementation of the remedial action, there will be increased heavy equipment
traffic on the waste area, various areas will be excavated, graded and
consolidated and the cap materials will increase the load on the waste materials.
All of these factors may increase the mobility of those more fluid components of
waste identified in the area. The Department believes that the impermeable cap
will provide better containment of these more fluid tars or tar derivatives and
thus slightly increase the reduction in exposure risk as compared to the
reinforced soil cap.
In summary, the Department agrees that the primary remedial action objective with
respect to human health is to eliminate the direct contact exposure hazard by
means of an engineered cover system. Other objectives of the remedial action
include eliminating exposure to other solid wastes mixed with the tars and tar
derivatives and minimizing migration of contaminants from the tar and other solid
waste mixed with the tar and tar derivatives to the surrounding environment.
With the site conditions as summarized above, and considering the remedy does not
include any active ground water remediation, the Department believes that a
properly engineered cover system that includes an impermeable, flexible membrane
32
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liner will maximize protection of human health and the environment by providing
better containment at the SWDA in a cost effective manner.
Comment: Hercules believes that the Proposed Plan does not provide the
flexibility required to create the most technically sound, cost-effective,
engineered cap system which meets the requirements of the technical committee.
The Proposed Plan should be less specific in the cap design to allow for
modification during the design phase. Additional geotechnical consideration is
needed to determine the structural design of the cap considering the nature of
the underlying waste. During the design, it may be determined that the specific
cap details outlined in the Proposed Plan may not be the most appropriate cap for
the SWDA.
Comment: Du Pont suggests that the words "or the equivalent" be added at the end
of the sentence on page 6, left hand column, under the Alternative 3 discussion:
"The impermeable cap would consist of a multi-layer system consisting of an upper
vegetative layer underlain by approximately 2 feet of clean fill, an impermeable
synthetic membrane liner, and a protective sub-layer for the liner, or the
equivalent." This wording would allow flexibility for minor design modifications
to ensure the integrity of the cap system.
Response: The Department agrees that it is appropriate to select the specific
capping materials during the design phase, and then to determine the necessary
thicknesses of each material layer based on the material type selected. However,
this recommendation made by the Department during.the Feasibility Study is in
no way inconsistent with the Proposed Plan requirement that the final engineered
cap include an impermeable barrier layer. The impermeable layer is a design
criteria, while the actual construction material used to create this barrier will
be determined during the design phase. Notwithstanding, the Department supports
Du Pont's recommendation to add the phrase "or the equivalent", as approved by
the Department, to the description of the multi-layer capping system to be
installed.
Comment: Page 7, under Alternative 3, states that the impermeable cap will
"provide a sufficient level of containment for the tar." The meaning of this
sentence is unclear because the tar has been shown not to leach into underlying
ground water. If the Department maintains that an impermeable cap is necessary,
a sentence should be added here that the impermeable cap will help prevent
further ground water degradation from the potential leaching of hazardous
constituents from the solid waste.
Response: The Department agrees with this recommendation, and will modify this
sentence in the Record of Decision to state that the impermeable liner will help
prevent ground water degradation from the potential leaching of hazardous
constituents from the solid waste material, and help to prevent exposure hazards
due to the potential for the soft tars to eventually breach the soil cover.
RISK ASSESSMENT
Question: Was there a Risk Assessment conducted to evaluate the effect of the
SWDA on the community, and if so, what were the results of that Risk Assessment?
Response: A Risk Assessment was not done to evaluate the effects of the SWDA on
the community, since it is not deemed to be a risk to the general population of
Gibbstown. The Risk Assessment that was conducted as part of the Remedial
Investigation evaluated the potential effects of the SWDA on people that may come
in direct contact with it, such as plant employees and trespassers. ^
Question: What were the findings of the Risk Assessment regarding the potential
effects to people that come in contact with the SWDA?
33
-------
Response: The Risk Assessment indicated that the primary risk of the SWDA was
potential carcinogenic effects due to direct contact with the tar. The risk for
.carcinogenic effects was estimated to be eight additional cancers for every one
thousand people directly exposed by contact with the tar on a daily basis over
a 70 year period .(a typical lifetime).
Question: What about the people that spent a lot of time at the site between
1952 and 1970? . A lot of people who are adults now used to ride their bikes and
built forts in that area as children. Are there any concerns about the effect
of the site on these people?
Response: No contaminants were found at the SWDA that were determined to be
acutely toxic or hazardous over a short term of exposure. As stated previously,
the tar material was determined to be the most hazardous component of the site.
However, the hazard presented by the tar would result only from chronic or long
term exposure, or exposure over much longer periods of time than those
experienced by children who may have played at the site in the past.
Comment: Although we (Du Pont) do not agree with the way the risk assessment was
conducted, nor its conclusions, it is important to clarify that the risk
discussed on page 4 is from direct exposure. Once covered, the pathway would be
eliminated, and no potential risk would be present. On page 4, right-hand
column, first sentence, the word "direct" should be added: "The most probable
and maximum carcinogenic risk is associated with direct exposure to tar and tar
soil."
Response: The Department concurs with this recommendation to modify the wording,
and accordingly, the above sentence will be modified to state that the most
probable and maximum carcinogenic risk is associated with direct exposure to tar
and soil.
Comment: Du Pont has concerns about the methodologies and assumptions used in
the risk assessment and believes it significantly overstates the risk. However,
it is clear that, once covered, the SWDA will pose no significant risk to human
health and the environment. Page 4 of the Proposed Plan discusses the risk
assessment. The calculated risk is driven by benzidine and carbazole, which were
not even detected in the tar. The major constituents actually detected in the
tar were not determined to present significant risk.
Du Pont does not believe that benzidine is a major contributor to risk because
it was never detected in the tar or in the soil. However, benzidine was detected
in one Toxicity Characteristic Leaching Procedure (TCLP) result for the tar. The
value used in the calculation was derived when the consultant back-calculated an
estimated concentration in the tar using the TCLP data and densities of water and
benzidine. This approach is technically flawed and does not conform with
standard Environmental Protection Agency (EPA) guidance.
Du Pont does not believe that carbazole is a major contributor to risk because
it was detected as a tentatively identified compound (TIC) in the tar, but not
in the soil or ground water beneath the tar. Because carbazole was detected as
a TIC, its actual identity and concentration are highly uncertain.
The limited data discussed above was incorrectly applied to a surface soil
exposure scenario. The assumption that tar should be evaluated in the same
manner as soil is technically flawed in that the tar does not dust and does not
behave similar to soil. The assumption that tar adheres to 20 percent of the
body surface, as soil does, is overly conservative.
The additive effect of these flawed assumptions results in the assessment that
dramatically overstates the risks associated with the tar. ^*"
34
-------
Response: The Department does not agree that the risk assessment is flawed. The
risk assessment follows accepted methodologies employed by the state and federal
government.
Comment: On page 7, under the overall protection of human health and the
environment evaluation of Alternative 2, the last sentence of the left-side
column should be removed: "For all media except the tar, this alternative would
adequately satisfy the remedial action objectives in terms of potential risk to
human health." Based on the above comments, the risks associated with the tar
are exaggerated. This statement also contradicts the Department's own assessment
of risk, which states that direct exposure is the only significant risk (see page
4) With restricted access to the area, the potential for direct exposure to
human health is eliminated.
Response* As stated in the responses above, the Department does not believe that
the risks associated with the tar are exaggerated. While direct contact with the
tar is the primary risk, elimination of that risk is not the only objective of
the remedial action. Other concerns include exposure and migration of other
wastes mixed with the tars and tar derivatives.
GENERAL STATEMENTS
Comment: I'm a local resident and also a former employee of Hercules. I'm sure
the Department and Hercules have done a lot of study on this and I'm thankful
that it can be capped and that we don't have to go.into any incineration. I think
incineration would really aggravate the people around here and cause a lot more
problems for us. But if you continue to study this and follow through with.
everything, I'm sure everything will be well.
Comment: I think that incineration would be a poor solution particularly because
our highly industrialized area here receives more than its share of pollution
right now. I also believe that Hercules is in good faith trying to.solve the
problem. It would seem to me that the solution of incineration would be out of
the question, particularly on-site. If you want to take it to somebody else's
back yard, all right, but not here. And I would say that really capping it would
probably be the best answer, particularly if you're monitoring to make sure that
our ground water is not becoming more contaminated. That's very important. I
would say that this is the only way you can go. So I believe that as long as you
are covering this and I know that Hercules in good faith is trying to do their
best, I think that we should take the most expedient method that would protect
our residents. I also sympathize with people that have talked about the
possibility of children getting into the area and I think that should be avoided
as much as possible.
Comment: At the public meeting held on August 10, 1994 the mayor of Gibbstown,
Raymond Williams made a statement to the audience. In the statement, the mayor
emphasized the following points:
a. Hercules, Inc. has a positive and cooperative relationship with the
township, and over the years has participated in a number of emergency
drills with township officials.
b. The incineration alternative (Alternative 4) would probably not be well
received by the citizens if it were selected as the final alternative.
c. The township officials are very concerned about the quality of the
drinking water, and consider the monitoring of the ground water at the
SWDA to be an important part of the remedial process. ^
d. At the public meeting held on August 10, 1994, a member of the audience
requested that the most up-to date site maps available be used in future
35
-------
handouts. The Department indicated that the map used in the handout provided
for the meeting gave an accurate representation of the SWDA conditions.
36
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Figure 1
Location Map
Hercules Higgins Plant
Glbbstown, New Jersey
. _ •. . • . -
Source: U.S.G.S. Topographic Quadrangle; Bridgeport. New Jersey. (1986)
Scale in Feet
17«
-------
Solid Waste Disposal Area
Northwest
Area
Solid
Waste
Pile
N
180
180
Scale In Feet
-------
Figure 3
Schematic Cross Section off
Existing Conditions at SWDA
Hercules-Hlgglns Plant
South
r-10
-5
Approximate
Water
Table
-10
L--15
100 50
100
Scale in Feet
(Horizontal)
-------
Figure M*
Conceptual Plan of Engineered
Soil Cap on SWDA
Hercules-Hlgglns Plant
i existing r*ouie—\
of Treated Water X '
Discharge Pipeline
MW-40
MW-40C
MW-40B
MW-41
4-
Legend
Solid Waste Disposal Area Boundary
3 Estimated Contours (MSL)
^-^ Cross Section Line
^- Ground Water Monitoring Well
» Abandoned Well
~~~] Solid Waste
"';,..•;''[ Exposed Tar
::.:.: Buried Tar
; 7T| Earthen Berm
Red Material Basin
MW-43 +
1QQ 50
100
Scale in Feet
1786A.03.Ot/05.21.93-MKB/05.24.93-CUP/1101
-------
Figure 5"
Schematic Edge Detail of Engineered Cap
Hercules-Hlgglns Plant
-Vegetated Cap
Surface
-Geotextile
Reinforcement
Shortest Pathway
to Future Exposure
of Tar
Soil Cap-
Keyed into
Native Soil
Schematic. Not to Scale
-------
Figure 0
SWDA Ground Water
Monitoring Well Network
Phase III Remedial Investigation
Solid Waste Disposal Area
Herculee-Hlgglns Plant
Qlbbatown, New Jersey
Exposed Tar
Buried Tar
Earthen Berm
Red Material Basin
Legend
~ ~ ~ Access Rood
Plank Walk to North Ditch
——- Hercules Property Line (Approximate)
— • —•— Solid Waste Area Boundary
= ; =• => Surface Water Drainage Feature
Abandoned Well
Ground Water Monitoring Welt
SG © Staff Gauge
| [ Solid Waste
-------
Table 1
Administrative Record Index
Hercules Incorporated - SWDA
o Administrative Consent Order entered into between Hercules and NJDEP;
Paragraph 34 requires Investigation of SWDA (July 1986)
o Phase I Work Plan (September 1986)
o Results of Phase I Investigation of SWDA (March 1988)
o Addendum to Results of Phase f Investigation (September 1988)
o Phase II Investigation scope of Work (September 1988)
o Phase II Supplemental Investigation Scope of Work (February 1989)
o Phase II Remedial Investigation Results, SWDA (June 1989)
o Phase II Addendum, Hercules Plant (June 1990)
o Phase III Remedial Investigation Work Plan and Quality Assurance Project Plan,
QAPP (April 1992)
o Response to Comments on Phase II Remedial Investigation Work Plan (June 1992)
o Revised QAPP for SWDA Remedial Investigation (June 1992)
o Revised Table 4-1 of the QAPP (July 1992)
o Analytical Method for Differentiation of Diphenylamine/Nitroeodiphenylamine
in QAPP (August 1992)
o Phase III Remedial Investigation, SWDA (February 1993)
o NJDEP Approval of Remedial Investigation Activities (May 1993)
o Final Revised Feasibility Study (October 1993)
o Revised Risk Assessment (December 1993)
o Public Meeting to Present Proposed Plan for SWDA (August 1994)
o USEPA Correspondence to NJDEP Regarding Selected Remedial Alternative (June
1995)
o NJDEP Correspondence to USEPA Regarding Decision to Modify Selected Remedial
Alternative (August 1995)
-------
Table 2
TBCs-New Jersey Soil Cleanup Criteria (pp»)
Hercules Incorporated - SWDA
Volatile OroanicB
Acetone
Acrylonitrile
Benzene
Broraodichloromethane
Bromoform
Bromomethane
2-Butanone (MEK)
Carbon tetrachloride
Chlorobenzene
Chloroform
Chloromethane
Dibromoch1oromethane
1,1-Dichloroethane
1,2-Dichloroethane
1,1-Dichloroethene
1,2-Dichloroethene (trans)
1,2-Dichloroethene (cis)
1,2-Dichloropropane
Ethylbenzene
4-Methyl-2-pentanone (MIBK)
Methylene Chloride
Styrene
1,1,1,2-Tetrachloroethane
1,1,2,2-Tetrachloroethane
Tetrachloroethylene
Toluene
1,1,1-Trichloroethane
1,1,2-Trichloroethane
Trichloroethene (TCE)
Vinyl chloride
Xylenes (Total)
Base/Neutral Extractables
Acenaphthene
Anthracene
Benzo(b)fluoranthene
Benzo(a)anthracene
Benzo(a)pyrene (BaP)
Benzo (k)fluoranthene
4-Chloroaniline
Bis(2-chloroethy1)ether
Bis(2-chloroisopropy1)ether
Bis(2-ethyIhexy1)phthalate
Butylbenzyl phthalates
Chrysene
Dibenz(a,h)anthracene
Di-n-buthyl phthalate
Di-n-octyl phthalate
Residential
Direct Contact
Soil Cleanup
Criteria
1000
1
3
11
86
79
1000
2
37
19
520
110
570
6
8
1000
79
10
1000
1000
49
23
170
34
4
1000
210
22
23
2
410
3400
10000
.9
.9
.66
.9
230
.66
2300
49
1100
9
.66
5700
1100
Non-Residential
Direct Contact
Soil Cleanup
Criteria
1000
5
13
46
370
1000
1000
4
680
28
1000
1000
1000
24
150
1000
1000
43
1000
1000
210
97
310
70
6
1000
1000
420
54
7
1000
10000
10000
4
4
.66
4
4200
3
10000
210
10000
40
.66
10000
10000
Impact to
Ground Water
Soil Cleanup
Criteria
100
1
1
1
1
1
50
1
1
1
10
1
10
1
10
50
1
100
50
1
100
1
1
1
500
50
1
1
10
10
100
100
50
500
100
500
1
10
100
^100
500
100
100
100
-------
Table 2 (continued)
1,3-Dichlorobenzene 5100
1,4-Dichlorobenzene 570
3,3'-Dichlorobenzidine 2
1,3-Dichloropropene (cia & trans) 4
Diethyl phthalate 10000
Dimethyl phthalate 10000
Fluoranthene 2300
Fluorene 2300
Hexachlorobenzene .66
Hexachlorobutadiene 1
Hexachlorocyclopentadiene 400
Hexachloroethane 6
Indendo(l,2,3-cd)pyrene .9
laophorone flOO
Naphthalene 230
Nitrobenzene 28
N-Nitrosodiphenylamine 140
N-Nitrosodi-n-propylamine .66
Pyrene 1700
1,2,4-Trichlorobenzene 68
Acid Extractables
4-Chloro-3-methyl phenol 10000
2-Chlorophenol 280
2,4 Dichlorophenol 170
2,4-Dimethyl phenol 1100
2,4-Dinitrophenol 110
2-Methylphenol 2800
4-Methylphenol 2800
Pentachlorophenol 6
Phenol 10000
2,4,5-Trichlorophenol 5600
2,4,6-Trichlorophenol 62
PAH's
Acenaphthene 3400
Anthracene 10000
Benzo(b)fluoranthene .9
Benzoja)anthracene .9
Benzo(a)pyrene (BaP) .66
Benzo (k)fluoranthene .9
Chrysene 9
Dibenz(a,h)anthracene .66
Fluoranthene 2300
Fluorene 2300
Indendo(l,2,3-cd)pyrene .9
Zsophorone 1100
Naphthalene 230
Pyrene 1700
Metals
Antimony 14
Arsenic 20
Barium 700
Beryllium 1
Cadmium 1
Copper 600
Lead (Total) 100
Mercury (Total) 14
10000
10000
e
5
10000
10000
10000
10000
2
21
7300
100
4
10000
4200
520
600
.66
10000
1200
10000
5200
3100
10000
2100
10000
10000
24
10000
10000
270
10000
10000
4
4
.66
4
40
.66
10000
10000
4
10000
4200
10000
340
20
47000
1
100
600
600
270
100
100
100
1
50
50
100
100
100
100
100
100
500
50
100
10
100
10
100
100
100
10
10
10
10
100
50
50
10
100
100
5
500
100
500
500
100
100
100
500
50
100
100
-------
Table 2 (continued)
Nickel (Soluble salts)
Selenium (Total)
Silver
Thallium
Vanadium
Zinc
Pesticides/PCBs
Aldrin
4,4'-DDD (p,p'-TDE)
4-4'-DDE
4-4*-DDT
Dieldrin
Endosulfan
Endrin
Heptachlor
Lindane
Methoxychlor
PCBs
Toxaphene
Other
Benzyl Alcohol
Cyanide
250
63
110
2
370
1500
.04
3
2
f 2
.042
340
17
.15
.52
280
.49
.1
10000
1100
2400
3100
4100
2
7100
1500
.17
12
9
9
.18
6200
310
.65
2.2
5200
2
.2
10000
21000
50
50
50
500
50
50
50
50
50
50
50
50
50
-------
Table 3
Potential Location Specific'ABARs
Hecules Incorporated - SWDA
Location
Citation
Requirement
Comments
Within 100-yr Floodplain
I.J.A.C. 7:26-10.3
40 CFR 264.18(b)
Hazardous wast* facilitiaa mat ba
daaignatad. constructed, oparatad
A aMtntainad to avoid washout
Construction of any BQBA
traataMot. atoraga. oz
disposal facilitiaa will have to
aiaat thasa raqulraaMOta
Hitbin Floodplaia
Exacutiva Order 11980.
Protection at Floodplaina. (40 CPK
«. AppandlT A)
Action to ovoid advacs* atfacts,
•Inimlsa potantial hasard. raatoca
A pzaaarva "**j«ir"1 & baoaticial
valuaa
Actiona in floodplaina will hava
to aaat tbaaa raquiraManta
Flood Bacazd Oraaa
Flood Haxard Araa Bacalatlooa
(I.J.A.C. 7:13)
Flood Basard Araa Control Act
(I.J.S.A. S8:1«A-SO)
Actiona to •iniaica haxarda &
advvraa aCCacta of construction
aetivitiaa
Activltiaa in dalinaatad watlamd
araaa will hava to awat tbaaa
ratiulovanta
Hatland*
Fraohwatar Hatlanda Protactioo Act
and Bulaa
(H.J.S.A. 13.98. B.J.A.C. 7:7A)
Exacutlva Ordar 1190. Frotaction
of Hatlaada
(40 CFB 6. Appaodiz A)
Actiona to adoladaa tha
daatruction. loaa. or
dagzadation of watlanda
Activitia* in dalinaatad watland
araaa will bava to aaat thaaa
raqulraannta
Araa Af facting Stzaaaj or Kivar
Flab and Hildllfa Coordination Act
(16 U.S.C. 66 at Baq.); 40 CFR
6.302)
Action to protact flab or wildlife
Tha Fiah and wildlifa
Coordination Act raquiraa
conaultatlon
with tha Oapt. of Flab & Gaaa
prior to any action that would
altar a body of watar of- tba US
-------
Table 4
Summary of Detailed Evaluation of Remedial Alternatives
Hercules Incorporated - SWDA
Evaluation Criteria
Overall Protection
of
Human Health &
the Environment
Compliance with
ARARS
Long-Term
Effectiveness
Reduction of
Toxicity, Mobility,
or Volume
Short-Term
Effectiveness
Implementability
(
Estimated Cost
Site-Wide Alternatives
1
No Action
Low
Low
Lqw
None
High
High
$201,000
2
Limited
Action
Low to
Moderate
Low
Low to
Moderate
None
High
High
$478,000
3
In-Place
Containment
High
Low
High
Moderate
Moderate
Moderate to
High
$1,956,000
4
SW and Tar
Incineration
High
Low to
Moderate
High
High
Low
Low
$36,875,000
North Ditch Alternatives
ND-1
No
Action
Moderate
Low
Moderate
None
High
High
$60,000
ND-3
Filling
Low to
Moderate
Low
Low to
Moderate
None
Very Low
Moderate to
High
$364,000
ND^
Dredging &
Restoration
Moderate
Low to
Moderate
Moderate
Low
Low
Low to
Moderate
$393,000
-------
Table 5
Contaminants of Concern/Media of Concern
Hercules Incorporated - SWDA
Media
Maximum Concentrations/
Contaminants of Concern
Ground Water
Surface Water
Sediment Fish Tissue
Benzene(6 ppm)
Toluene(20 ppm)
Cumene(710 ppm)
Cumene(180 ppb)*
Phenol(1.3 ppm)
2,4/2,6 dinitrotoluene
total (344 ppb)
Diphenylamine(640 ppm)
Chromium(692 ppm)
Lead(5.80 ppb)
Mercury(1.7 ppm)
Nickel(75.6 ppm)
Silver(16.7 ppm)
Zinc(756 ppm)
X
X
X
X
X
X
X
X
X
X
*below criteria of 300 ppb
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