United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA«OD/R03-93/171
September 1993
&EPA Superfund
Record of Decision:
Woodlawn County Landfill,
MD
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R03-93/171
TBto and Subtttto
SUPERFUND RECORD OF DECISION
Woodlawn County Landfill, MD
First Remedial Action - Final
& RapertDat*
09/28/93
7. Author**)
a Psffonnlng OrgtrtaOon Rapt No.
a Performing Organization Nuna and Address
10 Project Task/Work Unit No.
11. Centraet(C)erCmnKG)No.
(G)
12. Sponsoring Organization Nam* and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
O. Type orRaport* Parted Covsrsd
800/800
IS. Supplementary Notee
PB94-963907
1& Abstract (Umit: 200 words)
The 37-acre Woodlawn County Landfill is a former municipal landfill located in Colora,
Cecil County, Maryland. Land use in the area is predominantly residential. The
estimated 3,215 people who reside in the area use the ground water as their sole source
of drinking water. An unnamed creek crosses the southern end of the site, and in the
south-central area of the site, there is a retention basin to collect precipitation
runoff from the landfill, of which a portion contains a wetland area. Prior to 1960,
the site was a privately-owned sand and gravel quarry. From 1960 to 1978, Cecil County
operated a municipal landfill for the disposal and sometimes burning of municipal,
industrial, and agricultural waste. The Firestone Tire and Rubber Company initially
disposed of PVC sludge/ containing residual vinyl chloride, throughout the landfill.
From 1978 to 1981 disposal was limited to two disposal cells, known as Cell A and Cell
B/C under a State industrial waste disposal permit. In 1981, Firestone covered Cell
B/C with eight inches of clay and soil in response to an agreement with the State. In
1978, the landfill was closed for the disposal of municipal waste and the Woodlawn
Transfer Station began operations in the northeast corner of the site. The Transfer
Station, which is still operating, accepts and compacts municipal and commercial waste
(See Attached Page)
17. Document Analysis a. Dascrlptnri
Record of Decision - Woodlawn County Landfill, MD
First Remedial Action - Final
Contaminated Media: soil, debris, gw
Key Contaminants: VOCs (PCE, TCE, vinyl chloride), other organics (PAHs, pesticides,
phthalates), metals (cadium, manganese and mercury)
b. Identlfiera/Open-Ended Terms
c COSATIFIeUGroup
1& Availably Statsmsnt
19. Security Class (This Report)
None
20. Security Oas* (This Page)
None
21. No. of Page*
106
22. Mo*
(SeoANst-aa.18)
S»» Instructions on R*vun»
OPTIONAL FORM 272 (4-77)
(Formerly NnS-35)
Department ot Commerce
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EPA/ROD/R03-93/171
Woodlawn County Landfill, MD
First Remedial Action - Final
Abstract (Continued)
for disposal in another County landfill. From 1978 to 1990, liquid waste from the
compacting process was discharged to the Transfer Station septic system located west of
the Transfer Station. Following an overflow of effluent from the septic system to the
ground surface in 1990, liquids from the trash compactors were re-routed to an onsite
holding tank and periodically taken offsite to a nearby wastewater treatment plant. In
1981 and 1982, site investigations revealed acetone, methylene chloride, methanol, vinyl
chloride, benzene, and toluene contaminants in ground water samples taken from various
monitoring wells. This ROD addresses a final remedy for the contaminated soil and ground
water at the site. The primary contaminants of concern affecting the soil, debris, and
ground water are VOCs, including benzene, PCE, TCE, and vinyl chloride; other organics,
including PAHs, pesticides, and phthalates; and metals, including arsenic, cadium,
manganese, and mercury.
The selected remedial action for this site includes testing and excavating an estimated
400 yd^ of mercury-contaminated soil (>1 mg/kg mercury) from the former drain field of the
Transfer Station septic system; disposing of soil found not to exhibit the RCRA toxicity
characteristic for mercury at the center of the landfill and/or disposing of soil found to
be hazardous at an offsite RCRA-permitted disposal facility; relocating the currently
operating septic system drain field; capping a 31-acre portion of the landfill and
identifiable cells of PVC sludge with a clay cap, with a gas collection system; installing
an estimated 40 recovery wells; extracting contaminated ground water from the aquifer
using multiple recovery wells; using a three-step treatment process onsite consisting of
precipitation and flocculation/coagulation to remove manganese and other inorganics,
followed by air stripping to remove VOCs, and granular activated carbon to remove SVOCs;
discharging the treated water to the onsite stream; characterizing and disposing of any
treatment residuals offsite; implementing ground water, surface water, and air/landfill
gas monitoring programs; providing an alternate water supply or wellhead treatment to any
residents with wells that are contaminated with site-related contaminants at
concentrations that exceed the cleanup levels; characterizing and disposing of any
residual wastes that are generated from the wellhead treatment offsite; and implementing
institutional controls, including deed and ground water use restrictions. The estimated
present worth cost for this remedial action is $23,826,000, which includes an estimated
annual O&M cost of $1,609,000 for 30 years.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific soil excavation goals were based on the Summers Model and EPA guidance,
and include mercury 1 m/kg and vinyl chloride 7.7 ug/kg. Chemical-specific ground water
cleanup goals are based on risk- or health-based levels, and include arsenic 1 ug/1;
manganese 160 ug/1; PCE 1.5 ug/1; TCE 5 ug/1; and vinyl chloride 1 ug/1. If the risk- or
health-based levels are found to be lower than background, or below the levels that can be
detected, background levels or practical quantitation limits may be taken into account.
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RECORD OF DECISION
WOODLAWN LANDFILL SITE
DECLARATION
SITE NAME AND LOCATION
Woodlavn Landfill Site
Colora, Cecil County, Maryland
STATEMENT O? BASIS AND PURPOSE
This decision document presents the selected remedial action for
the Wgodlawn Landfill site (the Site) located in Colora, Cecil
County, Maryland, which was chosen in accordance with the
requirements of the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), as amended,
and, to the extent practicable, the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP), 40 C.F.R. Part 300.
This decision document explains the factual and legal basis for
selecting the remedial action for this Site. The information
supporting this decision is contained in the Administrative
Record for this Site.
The Maryland Department of the Environment (MDE) has not provided
a letter to EPA that indicates whether or not the State concurs
with the selected remedy. However, MDE has expressed concern
that: (1) several of the ground water cleanup levels set forth
in the Proposed Plan for the Site are more stringent than the
Maximum Contaminant Levels established under the Safe Drinking
Water Act, 42 U.S.C. §§ 300f et seg. ; and (2) the costs for
implementation of the selected remedy may exceed the cost
estimate presented in the Proposed Plan.
ASSESSMENT OF THE SITE
Pursuant to duly delegated authority, I hereby determine,
pursuant to Section 106 of CERCLA, 42 U.S.C. § 9606, that actual
or threatened releases of hazardous substances from this Site, if
not addressed by implementing the response action selected in
this Record of Decision (ROD), may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
DESCRIPTION OF THE REMEDY
The Woodlawn Landfill Site is a former municipal landfill
comprising approximately 37 acres. The remedial action selected
for the Site is a final remedy which will address contaminated
ground water, contaminated soils, and wastes buried at the Site.
The ground water contamination represents a significant threat.
Therefore, remediation of contaminated ground water will be
required. The wastes and contaminated soils at the Site pose a
relatively low long-term threat. Therefore, the wastes and
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contaminated soils will be addressed through a combination of
engineering and institutional controls.
The selected remedial action includes the following components:
• Excavation and disposal of the soils from the former
drain field of the Transfer Station septic system
• Relocation of the current drain field of the Transfer
Station septic system
• Capping of the landfill and identifiable cells of PVC
sludge
• Extraction of ground water
• Treatment of extracted ground water onsite and discharge
to the onsite stream
• Monitoring of ground water, the stream, and landfill gas
• Provision for an alternate water supply, if necessary
• Restrictions on the deed and ground water use
• Perimeter fencing
STATUTORY DETERMINATIONS
The selected remedial action is protective of human health and
the environment, complies with Federal and State requirements
that are legally applicable or relevant and appropriate to the
remedial action, and is cost-effective. This remedial action
utilizes permanent solutions and alternative treatment (or
resource recovery) technologies to the maximum extent
practicable, and satisfies the statutory preference for remedies
that employ treatment that reduces toxicity, mobility, or volume
as a principal element.
Because this remedial action will result in hazardous substances
remaining at the Site, a review by EPA will be conducted within
five years after the initiation of the remedial action, and every
five years thereafter, as required by Section 121 (c) of CERCLA,
42 U.S.C. S 9621(c), to ensure that the remedial action continues
to provide adequate protection of human health and the
environment.
9 -2-f - 1 3
Stanley L. Laskowski Date
Acting Regional Administrator
Region III
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RECORD OF DECISION
HOODLAWN LANDFILL SITE
DECISION SUMMARY
TABLE OF CONTENTS
1.0 SITE NAME, LOCATION AND DESCRIPTION 1
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 2
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION .... 4
4.0 SCOPE AND ROLE OF RESPONSE ACTION 4
5.0 SUMMARY OF SITE CHARACTERISTICS 5
5.1 Surface Features, Geology, Soils, Hydrogeology,
Hydrology 5
5.2 Nature and Extent of Contamination 9
5.2.1 Ground Water and Perched Water ...... 9
5.2.2 Domestic Wells 10
5.2.3 Wastes and Subsurface Soils 11
5.2.3.1 Landfill Contents and Cell A Area . 12
5.2.3.2 Cell B/C 12
5.2.4 Surface Soils 13
5.2.5 Drain Field Soils 13
5.2.6 Leachate Seeps, Seep Sediments and the
Retention Basin 13
5.2.7 Creek Surface Water and Sediments 14
6.0 SUMMARY OF SITE RISKS " 15
6.1 Contaminants of Concern 15
6.2 Human Health Risk Assessment 16
6.2.1 Exposure Assessment 16
6.2.1.1 Exposure Setting 16
6.2.1.2 Exposure Pathways 16
6.2.1.3 Exposure Scenarios 17
6.2.1.4 Quantitation of Exposure 21
6.2.2 Toxicity Assessment 22
6.2.3 Risk Characterization 23
6.2.3.1 Carcinogenic Risks 23
6.2.3.2 Noncarcinogenic Risks 25
6.3 Environmental Risk Assessment 26
6.4 Conclusion 26
7.0 REMEDIAL OBJECTIVES AND CLEANUP LEVELS 27
7.1 Remedial Objectives and Cleanup Levels for Ground
Water 27
7.2 Remedial Objectives and Cleanup Levels for Wastes . 28
7.3 Remedial Objectives and Cleanup Levels for Soils . 28
8.0 DESCRIPTION OF ALTERNATIVES 28
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9.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES .... 41
9.1 Overall Protection of Human Health and the
Environment 42
9.2 Compliance with ARARs 43
9.3 Long-Term Effectiveness and Permanence 46
9.4 Reduction of Toxicity, Mobility, or Volume Through
Treatment 47
9.5 Short-term Effectiveness 47
9.6 Implementability 48
9.7 Cost 49
9.8 State Acceptance 49
9.9 Community Acceptance 49
10.0 SELECTED REMEDY: DESCRIPTION AND PERFORMANCE
STANDARDS 50
11.0 GROUND WATER REMEDY IMPLEMENTATION 62
12.0 STATUTORY DETERMINATIONS 63
12.1 Protection of Human Health and the Environment . 63
12.2 Compliance with Applicable or Relevant and
Appropriate Requirements 64
12.3 Cost-Effectiveness 64
12.4 Utilization of Permanent Solutions and
Alternative Treatment Technologies to the
Maximum Extent Practicable 65
12.5 Preference for Treatment as a Principal Element . 65
13.0 DOCUMENTATION OF SIGNIFICANT CHANGES 65
References
Figures
Figure 1: Location of Domestic Wells
Figure 2: Ground Water Elevations, Regional Aquifer
Figure 3: Site Base Map
Figure 4: Plan View: Capping/Pump and Treat/Stream Discharge
Tables
Table 1: Constituents Detected in Site Ground Water Wells
Table 2: Constituents Detected in Off-site Residential Ground
Water wells
Table 3: Predicted Leachate Concentration of Constituents in
Site Ground Water from Subsurface Soils
Table 4: Toxicity Values for Chemicals of Potential Concern
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Table 5: EPA Categories for Potential Carcinogens
Table 6: Summary Health Risks and Hazards from Exposure to
Off-site Residential Ground Water
Table 7: Summary Risk Estimates (Current Conditions) for
Selected Child and Adult Receptors across Multiple
» Exposure Pathways
Table 8: Summary Ground Water Risk Estimates (Future Conditions)
for Selected Child and Adult Receptors
Table 9: Ground Water Cleanup Levels for Contaminants with
Carcinogenic Health Effects
Table 10: Ground Water Cleanup Levels for Contaminants with
Noncarcinogenic Adverse Health Effects
Table 11: Applicable or Relevant and Appropriate Requirements
(ARARs) and Guidance to Be Considered (TBCs) for the
Woodlawn Landfill Site
Responsiveness Summary
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DECISION SUMMARY
1.0 SITE NAME. LOCATION AND DESCRIPTION
The Woodlawn Landfill site (the Site) is a former municipal
landfill located approximately one-half mile north of the Town of
Woodlawn and one mile north of the intersection of Routes 275 and
276 in Colora, Cecil County, Maryland. It consists of
approximately 37 acres and is owned by the Board of Commissioners
of Cecil County (the County).
The Site is situated in an area of gently sloping fields and
meadows and gently to steeply sloping creek valleys. Rural
residences and properties surround it in all directions. (See
Figure 1. The Site occupies parcel 267 on Figure 1). The Site
is bounded on the east and south by Waibel Road. The northern
boundary of the Site is marked by a jeep trail that formerly
served as access to the property. The main access is now located
on the northeast corner of the Site, at the intersection of
Firetower and Waibel Roads.
Ground water is the sole source of drinking water for the 40 to
50 private residences immediately surrounding the Site. (The
closest residence is located approximately 100 feet from the
southeast boundary of the Site). It is estimated that 3,215
people utilize ground water drawn from the aquifer which flows
beneath the Site.
From 1960 until June of 1978, Cecil County operated a landfill at
the Site for the disposal of municipal, industrial and
agricultural wastes. In June of 1978, the landfill was closed to
municipal waste and the Woodlawn Transfer Station began operating
in the northeast corner of the Site. The Transfer Station, which
is still operating, accepts and compacts municipal and commercial
wastes for disposal in another County landfill. Until May of
1990, liquid wastes from the compacting process were discharged
to the Transfer Station septic system.
The primary medium of concern at the Site is contaminated ground
water, which presents both a carcinogenic and noncarcinogenic
risk to human health. Arsenic, vinyl chloride and beryllium are
the chemicals which contribute most to the current carcinogenic
risk. Vinyl chloride, benzo(a)pyrene, benzo(b)fluoranthene,
arsenic and 1,2-dichloroethane contribute most to potential
future carcinogenic risk. Manganese is the contaminant which
presents the highest current and potential future noncarcinogenic
risk.
There are also potential risks to ecological receptors at the
Site. Levels of cadmium and zinc in on-site seep sediments and
levels of mercury in the soils above the former drain field of
the Transfer Station septic system exceed the criteria that EPA
has determined are protective of ecological receptors. Levels of
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aluminum, copper, lead and silver in a stream that crosses the
southern tip of the Site exceed federal ambient water quality
criteria for the protection of aquatic life.
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
The 37-acre Site property was a privately-owned sand and gravel
quarry before 1960, when it was purchased by the County. The
County operated a municipal landfill at the Site from 1960 until
June 1978, when the landfill was closed to municipal waste under
order from the State of Maryland Department of Health and Mental
Hygiene (MDHMH), the predecessor agency to the Maryland
Department of the Environment (MDE). The landfill was open 24
hours a day without supervision until 1971, when the County hired
contractors to operate the facility.
In June of 1978, the Woodlawn Transfer Station began operations
in the northeast corner of the Site. The Transfer Station, which
is still operating, accepts and compacts municipal and commercial
wastes which are later hauled to the County's Hog Hill Landfill
for disposal. Liquid wastes derived from the compacted trash
were originally discharged to the Transfer Station septic system.
In May of 1990, following an overflow of effluent from the septic
system cleanout manhole to the ground surface, liquids from the
trash compactors were rerouted to an on-site holding tank.
Liquids in the holding tank are periodically taken to the
Northeast River Advanced Wastewater Treatment Plant in
Charlestown, Maryland.
From 1960 to 1978, agricultural, municipal and industrial wastes
were disposed of and sometimes burned at the Site. Some of the
wastes contained hazardous constituents or may have released
hazardous substances upon combustion.
State records pertaining to the Site document the disposal of
polyvinyl chloride (PVC) sludge by the Firestone Tire & Rubber
Company (Firestone). The PVC sludge, which contained residual
vinyl chloride, was initially disposed of throughout the
landfill. In March of 1978, Firestone began disposing of PVC
sludge in a designated disposal area, Cell A. On October 17,
1978, MDHMH issued an Industrial Waste Disposal Permit to
Firestone authorizing the disposal of PVC sludge in two
additional areas on the landfill property, Cells B and C. Sludge
disposal Cell C overlies Cell B. The two cells are referred to
together as Cell B/C. The approximate locations of Cells A and
B/C are shown in Figure 3.
On January 12, 1979, the State of Maryland Water Resources
Administration issued a Complaint and Order to the Cecil County
Commissioners, directing them to apply for a Maryland Water
Resources Designated Hazardous Substance Disposal Permit for the
landfill. By March 14, 1979, the County had complied. EPA
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subsequently determined that PVC sludge is not a hazardous waste
and the permit was never issued.
On July 16, 1980, MDHMH renewed Firestone's Industrial Waste
Disposal Permit. The State's renewal of the permit was
conditioned upon Firestone's agreement to adhere to specific
waste disposal practices, to document and report its waste
disposal activities at the Site, to implement a ground water
monitoring program at the Site, and to provide a final clay and
soil cover over PVC sludge disposal Cell C. In September 1980,
Firestone installed three ground water monitoring wells to
monitor releases from the PVC sludge disposal Cell B/C. Early in
1981 Cell C was covered with eight inches of clay and two and a
half feet of Boil.
In the summer of 1981, the State found contaminants including
vinyl chloride, benzene and toluene in ground water samples
collected from the monitoring wells located downgradient of Cell
B/C. On December 10, 1981, MDHMH issued a Complaint and Order
requiring Firestone to assess the nature and extent of ground
water contamination beneath the Site. On the same date, MDHMH
issued an identical Complaint and Order to the County.
In January of 1982, Firestone installed seven additional
monitoring wells in the vicinity of Cells A and B/C. The County
installed five monitoring wells on the landfill property in March
of 1982. The State installed an additional six wells in June of
1982. Analyses of monitoring well water samples revealed the
presence of acetone, benzene, methanol, methylene chloride,
toluene, vinyl chloride and other organic compounds in ground
water beneath 'the landfill property.
EPA proposed the Site for inclusion on the National Priorities
List (NPL) on January 22, 1987 and placed it the NPL on July 22,
1987. On June 13, 1988, EPA issued Special Notice Letters to
four potentially responsible parties (PRPs), giving them an
opportunity to perform a Remedial Investigation/Feasibility Study
(RI/FS) for the Woodlawn Landfill Site. On December 28, 1988,
two of the PRPs, the Firestone Tire & Rubber Company (now
Bridgestone/Firestone, Inc.) and Cecil County, entered into an
Administrative Order on Consent (AOC) with EPA whereby Firestone
and the County agreed to perform an RI/FS with EPA oversight, in
accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980, as amended (CERCLA).
The RI and FS Reports were completed on October 26, 1992 and
April 15, 1993, respectively. EPA developed a Proposed Remedial
Action Plan (Proposed Plan) for the Site based on the findings in
the RI/FS Reports.
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3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
Pursuant to CERCLA S 113(k)(2)(B)(i)-(v), the RI/PS reports and
the Proposed Plan for the Woodlawn Landfill Site were released to
the public for comment on May 26, 1993. These documents were
made available to the public in the Administrative Record located
at the EPA Docket Room in Region Ill's Philadelphia office, the
Elkton Public Library in Elkton, Maryland, and the Perryville
Public Library in Perryville, Maryland. The notice of
availability of these documents was published in the Cecil Whig
newspaper on May 26, 1993.
A public comment period on the documents was held from May 26,
1993 to July 26, 1993. In addition, a public meeting was held on
June 8, 1993. At this meeting, representatives from EPA and MDE
answered questions about conditions at the Site and the remedial
alternatives under consideration. A response to the comments
received during the public comment period is included in the
Responsiveness Summary, which is a part of this Record of
Decision (ROD).
This decision document presents the selected remedial action for
the Woodlawn Landfill Site in Colora, Maryland, chosen in
accordance with CERCLA, SARA, and, to the extent practicable, the
National Oil and Hazardous Substances Pollution Contingency Plan
(NCP), 40 C.F.R. Part 300. The selection of the remedial action
for this Site is based on the Administrative Record.
4.0 SCOPE AND ROLE OF RESPONSE ACTION
The remedy identified in this ROD is the sole response action
planned for the Woodlawn Landfill Site.
Contaminated ground water presents the principal risk to human
health at this Site due to current and potential future human
exposure via ingestion of drinking water. The selected
alternative will utilize treatment of ground water to: (1)
prevent exposure to contaminated ground water; and (2) restore
the affected aquifer.
Wastes buried at the Site are of concern to the extent that they
have the potential to act as a continuing source of ground water
contamination. In addition, it has been determined that
contaminant levels in several media at the Site may produce
adverse effects in exposed ecological receptors. These media
include soils above the former drain field of the Transfer
Station septic system, on-site leachate seep sediments, and
surface water of an unnamed creek that crosses the southern end
of the Site.
The wastes and contaminated soils at the Site pose a relatively
low long-term threat and will be addressed with a combination of
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engineering and institutional controls. These controls will:
(1) prevent migration of contaminants from the landfill and the
PVC sludge disposal cells to ground water and surface water; (2)
prevent exposure to the landfill contents, the contents of the
PVC sludge disposal cells, and contaminated soils and sediments;
and (3) control landfill gas to ensure protection of human health
and the environment. The surface water and sediments of the
unnamed creek will be monitored in order to provide a means for
detecting potential future adverse Site-related stream impacts.
5.0 SUMMARY OP SITE CHARACTERISTICS
5.1 Surface Features, Geology. Soils, Hvdroaeolocrv. Hydrology
Surface Features and Resources. A portion of the Site is covered
by dense trees. Tree cover is densest in the southern and
eastern portions of the landfill property. Grasses and shrubs
cover the north-central portion of the Site where landfill
operations took place.
The land surface in the north-central area of the Site slopes
gently to the southwest from the topographic high point near the
northeast corner of the Site. The southwestern portion of the
Site slopes steeply down to the unnamed creek.
In the south-central area of the Site, there is a retention basin
that was designed to collect precipitation runoff from the
landfill. A portion of the retention basin contains a palustrine
emergent scrub/shrub wetland. The flobdplain of the unnamed
creek is occupied by a palustrine broad-leaved deciduous forested
wetland.
An extensive palustrine forested wetland is located along the
unnamed creek, approximately one mile downstream of Waibel Road.
This wetland, which occupies an area of about 2000 feet by 500
feet, was not tested for Site contaminants during the RI.
However, it is an area where sediment deposition is expected to
occur and metals may accumulate.
There are no federally-listed or proposed endangered or
threatened species known to exist within a one-mile radius of the
Site. Although a bald eagle has been recorded approximately two
miles from the Site (in the southeast block of the Conowingo Dam
U.S. Geological Survey quadrangle), this federally-listed
endangered species is not expected at the Site due to the limited
availability of its preferred habitat of lakes, marshes, and
rivers. The Site does fall within the known range of the bog
turtle fClemmys muhlenbercril. a U.S. Department of the Interior
trust resource currently under consideration for federal listing
as a threatened species.
The Maryland Historic Trust (the Trust) conducted a Stage LA
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cultural resource survey for the Site. The Trust identified one
historic standing structure (McMaster's Delight) southeast of the
landfill property on the east side of Waibel Road (parcel 506 in
Figure 1). It concluded that activities at the Site would have
no effect on National Register-eligible archaeological resources
or historic standing structures.
Geology. The Site lies in the Piedmont Plateau region. The
rocks of the Piedmont Plateau are metamorphic and igneous. The
geology of the Site area has been described as sand and gravel
deposits overlying saprolite and the parent metamorphic bedrock.
The sand and gravel deposits are of the Upland Gravel unit and
are probably fluvial deposits of the ancestral Susquehanna River
system.
Two bedrock formations underlie the Site: a gneissic granite and
a metadiorite. The gneissic granite underlies the saprolite at
the soil/rock interface in all areas of the Site except the
northwestern section. The uppermost rock unit in this section is
metadiorite. The metadiorite dips beneath the gneissic granite
in a zone that appears to coincide with a lineament in the
northwestern portion of the Site that was identified on an aerial
photograph. The gneissic granite is a pink, coarsely crystalline
rock with weak foliation. The metadiorite is a black and white,
finely crystalline rock with pronounced schistosity. Both the
gneissic granite and the metadiorite contain interlocking
crystals of feldspar, quartz, hornblende, mica and other
minerals. These minerals contain silica, iron, aluminum,
manganese, calcium, sodium, potassium and trace elements. Upon
weathering, the gneissic granite and the metadiorite break down
into clay minerals, silica and oxides of iron and manganese. The
iron and manganese oxides become more soluble in oxygen-poor or
reducing environments, and can be transported by the ground
water. This natural source may account for some of the iron and
manganese in the ground water at the Site.
A thick layer of residual soil (saprolite) overlies the bedrock.
The residual soil is very granular. There is no evidence of a
layer that might restrict ground water flow between the soil and
bedrock. Fractures in the bedrock that intersect the surface
provide conduits for ground water flow across the contact between
the soil and the bedrock.
Soils. All unconsolidated materials lying above the bedrock are
classified here as soils. The stratigraphy of the soils from
bottom to top can be generalized as follows: residual soils
derived from weathering of the bedrock (saprolite); transported
soils including stream-derived sands and gravels (alluvium) and
soils washed from hills (colluvium); material such as waste and
reworked natural soils (fill).
Saprolite overlies the bedrock throughout the Site. The
6
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thickness of the saprolite varies from 90 feet in the northern
part of the Site to 15 feet in the southwestern part of the Site.
Deposits of alluvium and colluvium lie above the saprolite in
many areas of the Site. These deposits were the source materials
for a sand and gravel operation at the Site that predated the
landfill. The alluvium and colluvium contain layers of silty
clay and clay in some areas of the Site. The thickness of the
alluvium and colluvium varies from 10 feet in the northern part
of the Site to 50 feet in the western part of the Site.
The fill material at the Site consists of waste materials that
were deposited into excavations that were created during the time
when the sand and gravel operation was in existence, rearranged
alluvium and Colluvium, and mounds of reworked sand and gravel.
Hydrogeology. The hydraulically-connected saprolite and bedrock
comprise a single aquifer in the area of the Site. In the center
of the western boundary of the landfill property, there is an
irregular bedrock surface as interpreted from differences in
depths to bedrock from nearby borings. This irregularity appears
to be in or near the area of the contact between the gneissic
granite and the metadiorite. South of this area, the soil is
unsaturated, except for perched water zones. These factors
suggest that this contact zone may be a pathway for ground water
flow beneath the bedrock surface.
The ground water potentiometric surface for most of the Site is
in the saprolite. Near the southwestern corner of the Site (near
monitoring well ITB-4), the soil is unsaturated and the
potentiometric surface drops below the bedrock/soil interface.
The local ground water flow directions are shown in Figure 2.
There is a ground water divide, or high point in the northeast
area of the Site. Ground water from this divide flows
downgradient to either the south-southwest, west, or north-
northeast. The regional ground water flow is toward the
Susguehanna River and Chesapeake Bay (west-southwest). Local
ground water flow directions are in part influenced by local
topography (land surface and the buried bedrock surface), i.e.,
the flow directions are usually down slope. Local flow
directions are also influenced in the bedrock by fracture
orientations.
There is a discontinuous aquitard above the unconfined aquifer.
Clay lenses within the alluvium/colluvium in the unsaturated zone
intercept infiltration water and create perched water zones in
isolated areas of the alluvium/colluvium and fill material. The
clay lenses inhibit vertical water flow through the soil and fill
and redirect the water laterally to seeps south of Cell B/C and
in the western-central portion of the Site.
Site Drainage. Site surface drainage via overland flow is
7
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primarily southwestward toward the unnamed creek. Some of the
surface flow on the eastern side of the landfill property (near
Cell B/C) is channeled south, then west, into the retention
basin. When precipitation is heavy or of long duration,
accumulated runoff in the retention basin spills over into a man-
made swale that extends southwestward into the unnamed creek.
The unnamed creek, which flows to the west-northwest, enters
Basin Run Creek, a State-designated trout stream, approximately
one-and-a-half miles downstream from the Site. Basin Run
discharges into Octoraro Creek approximately three-and-a-half
miles northwest of the Site. Octoraro Creek flows westward until
it joins the Susquehanna River, which is the major source of
fresh water for the Chesapeake Bay.
Surface Water - Ground Water Interactions. The relationship
between surface water and ground water is characterized by the
following types of recharge: (1) recharge to ground water from
the surface of the Site; (2) recharge by precipitation to perched
water zones that supply seeps; and (3) recharge to surface water
streams by ground water.
The first type of recharge involves the flow of water from the
surface of the Site to the ground water. The topographic high
area that extends along the northern boundary of the landfill
property serves as a major recharge area. This recharge area is
the primary area in the vicinity of the Site which allows
precipitation falling on the ground to percolate through the soil
and into the regional aquifer.
The second type of recharge involves seeps which are fed by
ground water in the perched water zone located in the Cell B/C
area. Seeps were identified along a bank in the area of
monitoring well ITB-5. The seeps occur where a confining clay
layer intersects the ground surface, causing water flowing
downslope in the perched zone to surface. The perched water zone
is recharged directly by precipitation which percolates through
the surface soils and buried wastes. An additional seep was
identified in the northwest portion of the landfill. This seep
coincides with a subsurface lineament and flows from the landfill
to the west.
The third type of recharge involves ground water recharge to
surface water. Ground water flows to the southwest and to the
north away from the ground water divide located in the northeast
area of the Site. Ground water flowing to the southwest from the
divide eventually reaches and provides some recharge to the
unnamed creek. Ground water flowing north from the divide
eventually reaches and provides some recharge to Basin Run Creek.
8
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5*2 uafrupa and Extent of Copfc*1"*nation
In accordance with the Consent Order signed in 1988, Firestone
and the County performed a RI/FS to assess the nature and extent
of contamination at the Site. They also performed a Risk
Assessment in order to evaluate the human health risks and the
environmental impacts associated with exposure to Site
contaminants.
Three sources of contamination were identified at the site: PVC
sludge disposal Cell B/C, wastes disposed of in the general
landfill, and effluent from the Transfer Station septic system.
PVC sludge was not encountered in the area thought to be occupied
by disposal Cell A. Therefore, it was not possible to verify the
location of Cell A or to collect samples of the Cell A sludge for
analysis.
During the RI, ground water underneath the landfill property and
adjoining properties was sampled and analyzed in order to
determine the horizontal and vertical extent of ground water
contamination in the aquifer underlying the Site. Ground water
samples were also collected from residential wells surrounding
the Site. PVC sludge in Cell B/C, soils, leachate seeps and seep
sediments, surface water and stream sediments were also sampled
and evaluated. The sample results are summarized below.
5.2.1 Ground Water and Perched Water
Thirteen additional monitoring wells were installed at the Site
during the RI. Figure 3 identifies the ground water monitoring
points. Transfer Station water supply well TSTA-1 and monitoring
wells ITB-1 through ITB-6 tap the bedrock portion of the aquifer.
Well TSTA-1 was drilled to a depth of 228 feet. The bedrock
monitoring wells range in depth from 45 to 163 feet. Wells ITP-1
through ITP-3 are perched water monitoring wells that range in
depth from 11 to 20 feet. The remainder of the monitoring wells,
i.e., the F-, B-, OW-, and SW-series wells, wells ITS-1 through
ITS-3, and well TSW-l, are screened in the soil above the
bedrock. The depths of the soil wells range from 13 to 92 feet.
Ground water samples were collected from 30 monitoring wells and
the Transfer Station water supply well (TSTA-1). These samples
were analyzed for all Target Compound List (TCL) parameters plus
acrolein, acrylonitrile and 2-chloroethyl vinyl ether, and for
all Target Analyte List (TAL) parameters, except selenium and
antimony.
More than 40 different analytes were detected in ground water
samples collected from the monitoring wells located on and
adjacent to the landfill property, including several at
concentrations that exceed Maximum Contaminant Levels (MCLs) for
public drinking .water supplies. The contaminants that are of
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greatest concern from a human health perspective are vinyl
chloride, 1,2-dichloroethane and other volatile organic compounds
(VOCs) , polynuclear aromatic hydrocarbons (PAHs) , bis(2-
ethylhexyl)phthalate, pent ach lor opheno 1 , several pesticides,
arsenic, cadmium and manganese.
The vinyl chloride contamination is primarily limited to the F-
series wells that tap the soil aquifer in the area of PVC sludge
disposal Cells A and B/C. The highest concentration of vinyl
chloride detected in the ground water was 520 micrograms per
liter (Mg/L) in well F-6* Vinyl chloride was also detected in a
perched water monitoring well downgradient of Cell B/C (7 Mg/L in
well ITP-2), a bedrock well along the northern border of the
landfill (76 Mg/L in well ITB-1) , a bedrock well located
approximately 700 feet beyond the northern boundary of the
landfill property (0.71 Mg/L in well ITB-6) , bedrock wells along
the western border of the landfill (up to 0.6 Mg/L in well ITB-
3) , and bedrock wells in the south-central area of the landfill
(up to 14 Mg/L in well ITB-4) . Elevated levels of 1,2-
dichloroethane were detected in a soil monitoring well near the
northeastern corner of the landfill property (410 Mg/L in well
TSW-l) and a perched water monitoring well (15 Mg/L in ITP-2) .
Trichloroethene and tetrachloroethene were found in monitoring
well TSW-l at concentrations of 60 Mg/L and 8 Mg/L, respectively.
Maximum total PAH concentrations ranged from 6 Mg/L in perched
water monitoring well ITP-3 to 44 Mg/L in soil aquifer monitoring
well TSW-l and 13 pg/L in bedrock monitoring well ITB-2. Bis(2-
e thy lhexyl)phtha late was detected in ground water samples
collected from bedrock and soil aquifer and perched water
monitoring wells throughout the Site at concentrations up to 140
Mg/L (well OW-2) . Pentachlorophenol was detected in one soil
well (7 Mg/L in well B-4) and in one bedrock well (4 Mg/L in well
ITB-4) . Various pesticides were found in samples collected from
seven soil monitoring wells, a perched water monitoring well and
a bedrock monitoring well. The highest pesticide concentration
was 0.24 Mg/L of Endosulfan I, which was found in well OW-l.
Arsenic and cadmium were detected in ground water and perched
water samples at concentrations up to 8 Mg/L (well SW-1) and 119
Mg/L (well F-6) , respectively. Elevated levels of iron and
manganese were found in the aquifer underlying the Site and in
the perched water zones on-site. Maximum manganese
concentrations ranged from 12,600 Mg/L in ground water extracted
from the bedrock (well ITB-4) to 24,200 Mg/L in ground water
extracted from the soil (well F-7) to 1,940 Mg/L in the perched
water zones (well ITP-1) . Maximum iron concentrations ranged
from 10,200 Mg/L (bedrock well ITB-4) to 43,500 Mg/L (soil well
F-7) to 59,500 Mg/L (perched water monitoring well ITP-1) .
5.2.2 Domestic Wells
Thirteen domestic wells were sampled by Firestone and the County
10
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in both March and November of 1990, and analyzed for the TCL
parameters plus acrolein, acrylonitrile and 2-chloroethyl vinyl
ether, and for the TAL parameters, except antimony and selenium.
EPA analyzed VOCs in samples collected from seven additional
domestic wells in August of 1991.
Most of the domestic wells in the area of the Site (Figure 1) are
cased to a depth of five feet below the bedrock surface. Below
this depth, the well bores are open to the bottom of the hole.
Well completion reports indicate that two domestic wells may vary
in design from the others near the Site. The well casing at
parcel 309 may have been installed to a depth above the bedrock
surface. The well at parcel 506 may not extend into the bedrock.
Site-related contaminants were found in two residential wells.
The domestic well at parcel 309 is contaminated with detectable
levels of vinyl chloride. The highest concentration of vinyl
chloride detected in the well was 0.6 M9/L, which is below the
MCL for that chemical. A carbon adsorption unit was installed at
this residence in December of 1990 in order to remove vinyl
chloride. No contamination has been detected in the treated well
water. Water collected from the domestic well at parcel 506 was
found to contain elevated levels of manganese. The highest
concentration of manganese detected in this well was 3,060 nq/L.
On September 9, 1993, EPA approved of a work plan submitted by
Firestone and the County for the design and installation of a
treatment system to reduce the level of manganese in the domestic
well at parcel 506 to an acceptable health-based level.
Other residential wells may be contaminated. Arsenic was found
in ground water samples collected from the domestic wells located
on parcels 530 and 516. However, the level of arsenic detected
in these samples (2 Mg/L) appears to be within the range of
background arsenic concentrations found in Cecil County ground
water. Beryllium was found at a concentration of 2.2 Mg/L in
one of three samples from domestic wells on each of parcels 515
and 516. The beryllium detected in these samples may be the
result of laboratory contamination; beryllium was not detected in
ground water beneath the landfill property.
5*2*3 Wastes and s^^surface Soils
During the RI, Firestone and the County completed 30 borings in
the waste material at the Site in order to define the vertical
and lateral extent of the wastes and to evaluate treatment and
control options. Five borings were completed in the general
landfill area. Twenty borings were completed in the Cell B/C
area and five in the area thought to be occupied by Cell A. The
samples were analyzed for the TCL parameters plus acrolein,
acrylonitrile and 2-chloroethyl vinyl ether, and for the TAL
parameters, except antimony and selenium. EPA completed eight
additional borings in October 1992 in order to further evaluate
11
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the volatile organic constituents of the waste material in PVC
sludge disposal Cell B/C.
5.2.3.1 Landfill Contents and Cell A Area
Nineteen samples were collected from ten borings-in-waste
completed in the general landfill and suspected Cell A areas.
Low concentrations of organic compounds and metals were found in
the fill material in the general landfill area, in the native
saprolite surrounding the fill, and in the suspected area of Cell
A. The organic chemicals included VOCs (which were different
from the VOCs found at levels of concern in the ground water) and
semivolatile organic compounds, including bis(2-ethylhexyl)-
phthala.te. Generally low levels of inorganic elements were
detected in the subsurface soil and waste samples.
It should be noted that the analytical results for the 19
landfill waste and subsurface soil samples are not considered to
be representative of all of the wastes and contaminated soils in
the landfill. A statistical sampling plan would need to be
implemented in order to obtain a representative measure of the
chemical constituents of the landfill wastes. However, detailed
characterization of a landfill's contents is costly and the
volume and heterogeneity of landfill contents often makes
treatment impracticable (Conducting Remedial Investigations/
Feasibility Studies for CERCLA Municipal Landfill Sites,
EPA/540/P-91/001, February 1991 [hereafter, "EPA Municipal
Landfill Guidance"]). Therefore, such detailed characterization
is generally not necessary since containment, in accordance with
the NCP, is often the most practicable technology and does not
require such information.
5.2.3.2 Cell B/C
Twenty-seven samples of PVC sludge were collected from 20
different boreholes drilled into the one-acre Cell B/C waste
area, consistent with the EPA Municipal Landfill Guidance
regarding potential hot spots at municipal landfill sites.
Generally low concentrations of organic compounds and metals were
found in the PVC sludge samples. Among the VOCs found in the
samples were 1,2-dichloroethane, trichloroethene and vinyl
chloride. The highest concentration of vinyl chloride detected
in the Cell B/C sludge material was 7.95 milligrams per kilogram
(mg/kg). The mean concentration of vinyl chloride in the Cell
B/C PVC sludge was estimated to be 290 micrograms per kilogram
(Mg/kg), based on the analytical data collected for the RI and
treatability studies and the additional sludge sample analyses
conducted by EPA. Semivolatile organic compounds detected in the
Cell B/C sludge samples included bis(2-ethylhexyl)phthalate (at
levels up to 1,200,000 jig/kg) and other phthalates. Generally
low levels of inorganic elements were detected in the Cell B/C
waste material.
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5.2*4 **mff*c< Soils
Eleven surface soil samples were collected from the general
landfill area and the PVC sludge disposal cell areas. These
samples were analyzed for the TCL parameters plus acrolein,
acrylonitrile and 2-chloroethyl vinyl ether, and for the TAL
parameters, except antimony and selenium. Low levels of organic
compounds were detected, generally at concentrations close to the
method guantitation level. These compounds included VOCs and
semivolatile organic compounds, including PAHs. Inorganic
elements, including arsenic and beryllium were also detected in
the surface soils at background levels.
5.2.5 Drain Field Soils
Thirteen subsurface soil samples were collected from areas above
and below the former septic system drain field, and three surface
soil samples were collected from areas downslope of the manhole
at the head of the former drain field. (Two of the surface soil
samples were collected and analyzed by EPA.) The purpose was to
evaluate the impact of releases from the septic system on Site
soils and the potential for contaminants in drain field soils to
leach into ground water. The drain field soil samples were
analyzed for the TCL and TAL parameters.
Low concentrations of organic compounds were detected in drain
field soils, generally at levels close to the method guantitation
limits. These compounds included VOCs, semivolatile organic
compounds, including PAHs, and several pesticides. Several
inorganic elements, including arsenic (at levels up to 22.1
mg/kg), mercury (at levels up to 3.9 mg/kg), and beryllium were
found in the drain field soils. The levels of beryllium in the
drain field soils are within the range of background levels in
Cecil County.
5.2.6 Laachata 8>eps» Saep Sediments and tha Retention Basin
A sediment sample was collected from each of three leachate seeps
identified during the RI and from the retention basin in the
south-central area of the landfill. A leachate sample was also
collected from each of the three seeps. A surface water sample
was collected from the retention basin. These samples were
analyzed for the TCL parameters plus acrolein, acrylonitrile and
2-chloroethyl vinyl ether, and for the TAL parameters, except
antimony and selenium.
Leachate seep samples contained levels of the VOCs benzene,
carbon disulfide, chlorobenzene, ethylbenzene, toluene and total
xylenes, with maximum concentrations ranging from 2 M9/I* to 82
Mg/L, and levels of the semivolatile organic chemicals benzoic
acid, 1,4-dichlorobenzene, diethylphthalate, naphthalene and
phenol, with maximum concentrations ranging from 3 Mg/L to 38
13
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M9/L. Levels of aluminum (up to 138 pg/L), copper (2.7 /ig/L) ,
iron (up to 69,400 M9/L), lead (up to 10.7 pg/L), manganese (up
to 1,090 Mg/L)» nickel (up to 22.4 ^g/L), zinc (up to 23.0 Mg/L)
and other metals were also found in the leachate seep samples and
the surface water sample collected from the retention basin.
Sediment samples collected from seep areas and the retention
basin contained VOCs, including acetone, chloroform, 2-butanohe,
toluene and total xylenes, with maximum concentrations ranging
from 2 Mg/kg to 78 Mg/kg, and semivolatile organic compounds,
including bis(2-ethylhexyl)phthalate at levels up to 5,800
and a wide range of PAHs, with maximum concentrations ranging
from 160 Mg/kg to 780 jig/kg. Elevated levels of cadmium (up to
10.5 mg/kg) and zinc (up to 876 mg/kg) were detected in seep
sediments. Arsenic and beryllium were also detected in seep
sediments at background levels.
5.2.7 creek surface water and Sediments
During the RI, six sediment samples and six surface water samples
were collected from upstream and downstream areas of the unnamed
creek that flows across the southern tip of the Site. The
samples were analyzed for the TCL parameters plus acrolein,
acrylonitrile and 2-chloroethyl vinyl ether, and for the TAL
parameters, except antimony and selenium.
Low levels of the semivolatile organic compounds di-n-butyl-
phthalate, N-nitrosodiphenylamine and pyrene were found in
downstream surface water samples. Di-n-butylphthalate was also
found in an upstream surface water sample at a level similar to
the downstream level.
Twelve metals were found in downstream surface water samples and
eleven were detected in upstream surface water samples. The
maximum concentration of manganese found in downstream surface
water samples (191 ng/L) exceeded the highest level of manganese
detected in upstream surface water samples (21.4 /ig/L). Maximum
downstream concentrations of some metals were slightly elevated
compared to maximum upstream concentrations of those metals:
aluminum (143 ng/L and 105.9 Mg/L, respectively); copper
(6.6 Mg/L and 4.2 Mg/L, respectively); iron (180 /ig/L and
118.8 Mg/L, respectively); nickel (7.9 M9/L and 6 pg/L,
respectively); and zinc (13.3 M9/I* and 9.5 ng/I>, respectively).
Lead was found in a downstream sample at a maximum concentration
of 3.7 Mg/L but was not detected in upstream surface water
samples. Five other metals occurred at comparable levels in
upstream and downstream samples.
Low levels of the VOCs chloroform and tetrachloroethene were
found in upstream creek sediments. Chloroform was found in one
downstream sediment sample at a concentration of 2 pig/kg.
Semivolatile organic compounds, including benzoic acid at a level
14
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of 430 Mg/kg, bis(2-ethylhexyl)phthalate at a level of 140 /*g/kg,
and several PAHs at levels ranging from 120 Mg/kg to 160 M9/kg,
were found in downstream sediment samples. Bis(2-ethylhexyl)-
phthalate was also found in an upstream sediment sample at a
level of 140 /ig/kg. Downstream levels of several metals in creek
sediments, including chromium, cobalt, copper, iron, manganese
and nickel, were somewhat elevated compared to upstream levels.
6.0 SUMMARY OF SITE RISKS
A baseline Risk Assessment was prepared in order to identify and
define possible existing and future health risks and potential
environmental impacts associated with exposure to the chemicals
present in the various environmental media at the Site if no
action were taken. The baseline Risk Assessment provides the
basis for taking action and indicates the exposure pathways that
need to be addressed by the remedial action. The baseline Risk
Assessment can be found in the Remedial Investigation Report
(Revision 01, October 1992) prepared by International Technology
Corporation (IT).
6.1
Since the principal risk to human health presented by conditions
at the Site is risk from exposure to contaminated ground water,
the primary contaminants of concern are those chemicals detected
in the ground water at the Site and those chemicals in the wastes
buried at the Site which have the potential to contaminate ground
water as a result of leaching. These chemicals are presented in
Tables 1 through 3.1
In addition, mercury was detected in soils above the former drain
field of the Transfer Station septic system; cadmium and zinc
were found in on-site seep sediments; and aluminum, copper, lead
and silver were detected in surface water samples collected from
downstream areas of the unnamed creek. These metals are
1 As noted in Section 5.2.3.1, characterization of the
landfill wastes during the RI would have been costly and was
determined to be unnecessary since containment is the most
practicable technology for managing a large volume of
heterogeneous wastes in a municipal landfill. The PVC sludge in
disposal Cell B/C was adequately characterized and its leaching
potential evaluated during the RI. The results are summarized in
Table 3 of this ROD. Since the wastes in the landfill were not
fully characterized, it was not possible to reliably determine
the leaching potential of those wastes. However, Tables 1 and 2
include contaminants of concern found in ground water at the Site
which have not been detected in the Cell B/C wastes. It is
reasonable to conclude that those contaminants were derived from
the wastes in the landfill and from the natural soils.
15
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contaminants of concern for ecological receptors.
6.2.1 Rvpeaura Assessment
The objective of the exposure assessment is to estimate the
amount of each chemical of potential concern at a site that is
actually taken into the body (i.e., the intake level or dose).
The primary components of the exposure assessment include a
characterization of the exposure setting, a pathway analysis,
identification of possible exposure conditions, and an estimation
of exposure. The results of the exposure assessment are combined
with chemical-specific toxicity information to characterize
potential risks.
6.2.1.1 Exposure Setting
Although some areas of the Site are fenced, most of the Site
boundary is unfenced. Therefore, trespassing is possible at the
Site. Potentially exposed populations include residential
populations located near the Site and child or adolescent
trespassers.
6.2.1.2 Exposure Pathways
A complete exposure pathway consists of the following elements:
(1) a chemical source or a mechanism for contaminants to be
released into the environment; (2) a medium through which
contaminants may be transported, such as water, soil or air; (3)
a point of actual or potential contact with contaminants
(exposure point); and (4) a route or mechanism of exposure, such
as ingestion, inhalation, or dermal contact at the exposure
point. Both current exposure pathways and potential future
exposure pathways were evaluated in the Risk Assessment.
As noted in Section 5.2, above, three sources of contamination
were identified at the Site. The release of contaminants into
the environment was documented during the RI.
The following contaminated media and potential routes of exposure
were evaluated in the Risk Assessment:
• Ground water pathway
- Ingestion of contaminated ground water, including
potential leachate from subsurface soils and PVC
sludge
Inhalation, during showering, of volatilized ground
water contaminants, including contaminants in
potential leachate from subsurface soils and PVC
16
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sludge
- Dermal contact, during showering, with contaminated
ground water, including potential leachate from
subsurface soils and PVC sludge
• Soil pathway
- Incidental ingestion of contaminated surface soils
- Inhalation of wind-borne surface soil particulates
- Incidental dermal contact with contaminated surface
soils
• Sediment pathway
- Incidental ingestion of sediments, including seep,
retention basin and creek sediments
- Incidental dermal contact with sediments, including
seep, retention basin and creek sediments
• Surface water pathway
- Dermal contact with constituents in surface water,
including leachate and surface water in the creek and
retention basin.
6.2.1.3 KTTDO8MT< Scenarios
The exposure assessment considered current and potential future
use of contaminated ground water and current recreational use of
the Site. The averaging time used in all exposure pathway
calculations for carcinogens is based on an adult lifetime of 70
years. The averaging time used in all exposure pathway
calculations for chemicals with noncarcinogenic health effects is
equal to the duration of exposure. The other assumptions used to
estimate exposure point concentrations and to quantify exposure
are summarized below for each pathway evaluated in the Risk
Assessment.
Ground Water Pathway. The risk associated with exposure of area
residents to contaminants present in residential well water was
quantified in the Risk Assessment. Potential future exposure to
contaminants present in ground water beneath the landfill
property was also considered in the Risk Assessment based on an
assumption that a public water supply well would be placed in the
center of the existing contaminant plume. A second future use
scenario considered exposure to ground water contaminated with
the highest levels of vinyl chloride that were predicted to occur
in the aquifer beneath the landfill property and beyond the
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property boundary 70 years in the future. (The ground water flow
and solute transport model that was used to simulate the
migration of vinyl chloride is described in detail in the Phase
III Report [Revision 01, November 1991] prepared by IT.) In
addition, contaminant concentrations that may occur in ground
water as a result of leaching from subsurface soils and wastes
were considered in the Risk Assessment.
Potential routes of exposure to constituents in ground water are
discussed in Section 6.2.1.2, above. A number of assumptions are
used to calculate the dose for each exposure route since it is
seldom possible to measure a specific dose. The following
assumptions were used to estimate exposure to ground water
constituents:
• Receptors include a 30-kilogram (kg) child ingesting 1.0
liter per day (L/day) and a 70-kg adult ingesting 2.0
L/day every day for 17 and 30 years, respectively.
Showering is assumed to occur daily, with adult and child
receptors being exposed for 12 minutes per day.
• Inhalation rates of adult and child receptors are 10
liters per minute (L/min) and 13 L/min, respectively.
• The total skin surface area available for contact during
showering or bathing for a child is 10,455 square
centimeters (cm2) and the total surface area for an adult
is 19,400 cm2.
• Dermal permeability coefficient factors presented in
EPA's Interim Guidance for Dermal Exposure Assessment,
Review Draft (March 1991), were used to estimate the mass
of organic compounds transferred through the skin.
• It was assumed that significant levels of heavy metals
would not be dermally absorbed from water on the skin
surface.
Two mathematical models were utilized in the exposure assessment
for the ground water pathway. The shower model developed by
Foster and Chrostowski (1986)2 was used to estimate a shower
dose, expressed as mg/kg per shower. The contaminant
concentrations that may occur in ground water as a result of
leaching from subsurface soils and wastes were derived using the
model described by Summers, et. al. (1980).
Surface Soil Pathway. Direct contact with and incidental
ingestion of soil, and inhalation of wind-borne soil
particulates, were evaluated as potential routes of exposure for
2 See the List of References appended to this ROD.
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a child or adolescent trespasser visiting the area during
weekends and other nonschool periods and for an adult dropping
off refuse at the Transfer Station. Inhalation of wind-borne
soil particulates was also evaluated as an exposure route for
individuals residing northeast of the Site on Firetower Road.
The following assumptions were used to estimate current exposure
from potential contact with surface soil:
• The exposure frequency for both an adult and child
exposed off-site to windblown dust was assumed to be 350
days per year (days/yr). The child trespasser exposure
frequency was assumed to be four times a month for nine
months/ or 36 days/yr. The adult visitation frequency
for refuse drop off was assumed to be once a week, or 52
days/yr.
• The off-site exposure duration was assumed to be 30 and
17 years for an adult and child, respectively. The
exposure duration for a child six to fourteen years old
trespassing on-site was assumed to be nine years.
• The soil ingestion rate for children and adults was
assumed to be 100 milligrams per day (mg/day).
• It was assumed that one hundred percent of the chemical
adsorbed on soil particles would be absorbed by the
adult's or child's gastrointestinal tract.
• The wind direction was assumed to be originating out of
the southwest 100 percent of the time, i.e., blowing
toward homes closest to the Site on Firetower Road.
• The inhalation rate was assumed to be 20 cubic meters per
day (m3/day) for an adult and 19.2 m3/day for a child.
• It was assumed that 100 percent of the constituents of
soil particulates are absorbed following inhalation.
• The skin surface area available for contact was assumed
to be 4,440 cm2 for a child (the estimated surface area
of the hands, arms and legs) and 2,000 cm2 for an adult
(the estimated surface area of the forearms and hands).
• The soil adherence factor was assumed to be 1.45
milligrams per square centimeter per day (mg/cm2/day).
• It was assumed that one percent of the cadmium in soil is
dermally absorbed. No other soil constituents were
assumed to be available for dermal absorption.
Three air models were used to determine particulate
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concentrations at the Site: a soil emission model to determine
particulate emission rates from wind erosion (U.S. EPA, 1984); a
box model to estimate on-site exposure (Hannah, et al., 1982);
and a Gaussian dispersion model to estimate off-site migration of
soil particulates (Turner, 1970).
Subsurface Soil Pathway. Direct routes of exposure to subsurface
soils and wastes (dermal contact, incidental ingestion and
inhalation) were not considered since no excavation or subsurface
disturbance is expected to occur at the Site. However, as noted
above, the model described by Summers, et al. was used to
estimate the concentration of contaminants that would occur in
ground water as a result of leaching from subsurface soils and
wastes.. Exposure to the leachate-contaminated ground water was
evaluated in the Risk Assessment based on the assumptions
outlined above for the ground water pathway.
sediments Pathway. Direct contact with sediments and subsequent
incidental ingestion were considered potential routes of exposure
for a child trespassing on the Site. The following assumptions
were used in evaluating a child's exposure for the trespasser
scenario:
• The skin surface area available for contact with the seep
and settling basin sediments was assumed to be 4,440 cm2
(the estimated surface area of the arms, hands and legs).
• The skin surface area available for contact with the
surface water sediments was assumed to be 1,800 cm2 (the
estimated surface area of the hands, feet and lower
legs).
Other exposure parameters, including exposure frequency and
duration, and ingestion and absorption rates, were assumed to
have the same values as the parameters used in the scenario for
exposure of a child trespasser to surface soils.
Surface Water Pathway. Direct contact with surface water
constituents during wading in the unnamed creek and trespassing
on the landfill property were considered as potential routes of
exposure for a child trespasser. Ingestion of potentially
contaminated fish was not considered since the creek has a
limited ability to support recreational fishing due to its
shallow depth. The following exposure factors were used in
evaluating the child's exposure in the surface water exposure
scenario:
• The skin surface area available for contact with surface
water was assumed to be 1,800 cm2 (the estimated surface
area of the hands, feet and lower legs).
• Dermal permeability coefficient factors presented in
20
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EPA's Interim Guidance for Dermal Exposure Assessment,
Review Draft (March 1991), were used to estimate the mass
of organic contaminants transferred through the skin.
• It was assumed that significant levels of heavy metals
would not be dermally absorbed from surface water.
The frequency and duration of exposure to surface water were
assumed to be the same as the frequency and duration of exposure
of a child trespasser to surface soils.
6.2.1*4 Quantitation of Exposure
The reasonable maximum exposure (RME) concentration was used to
estimate the level of exposure to chemicals of potential concern.
The RME concentration is defined as the upper 95th percent
confidence limit on the arithmetic mean of the analytical data
for each chemical of potential concern. For some chemicals, the
calculated upper 95th percent confidence level exceeded the
maximum concentration found in a particular medium. In those
cases, the exposure point concentration was set equal to the
maximum detected concentration.
Contaminated ground water was the only medium at the Site found
to pose a threat to human health. The chemicals found in ground
water samples collected from Site monitoring wells and the RME
values for the chemicals are presented in Table 1. The chemicals
found in ground water samples collected from residential wells
and the RME values for the chemicals are presented in Table 2.
The concentrations of contaminants predicted to occur in ground
water as a result of potential future leaching from Cell B/C
wastes is presented in Table 3.
Although ground water is the only medium at the Site that
contains contaminants at levels that would result in unacceptable
levels of risk to exposed human populations, all of the chemicals
with available toxicity factors in each of the environmental
media evaluated at the Site were used to estimate potential
health risks in the Risk Assessment. Exposure scenarios for each
pathway were evaluated together with the exposure point
concentrations to derive intakes (expressed as mg/day) for each
population subgroup. By dividing the intake value by the
appropriate body weight, a dose expressed in milligrams of
contaminant per kilogram of body weight per day (mg/kg/day) was
determined for each age group. This dose is referred to as the
chronic daily intake (GDI). The GDI values for each exposure
pathway are presented in Appendix N of the RI Report.3
3 The oral reference dose (RfD) for manganese was revised
subsequent to the preparation of the RI Report. Therefore, the
CDI values for manganese in Appendix N of the RI Report do not
21
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6.2.2 Toxicitv Assessment
A toxicity evaluation of the chemicals present at the Site was
conducted in order to identify relevant carcinogenic potency
factors and chronic reference doses against which daily intake
levels could be compared.
Cancer slope factors (CSFs) have been developed by EPA's
Carcinogenic Assessment Group for estimating excess lifetime
cancer risks associated with exposure to potentially carcinogenic
chemicals. Cancer slope 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. CSFs, which are expressed in units of
(mg/kg/day)"1, are multiplied by the estimated chronic daily
intake of a potential carcinogen, expressed 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 CSF. Use of this approach makes
underestimation of the actual cancer risk highly unlikely. CSFs
for contaminants of potential concern at the Site which
contribute to the carcinogenic risk are presented in Table 4.
Table 4 also reflects the degree of confidence in the data used
to determine that the chemical is a human carcinogen. EPA
toxicologists recognize that the risk associated with a known
human carcinogen, based on epidemiological studies, should be
evaluated differently from the risk attributed to a chemical that
causes tumor growth in laboratory animals. Each carcinogen is
assigned to a group according to the quality and quantity of
evidence for carcinogenicity in humans and nonhuman animals. The
definitions of Cancer Groups A through E are presented in Table
5.
Reference doses (RfDs) have been developed by EPA for indicating
the potential for adverse noncancer health effects from exposure
to toxic chemicals. The model used to develop RfDs is based on
the assumption that threshold levels exist for certain toxic
effects. Two chronic toxicity parameters are used to establish
RfDs: the lowest-observed-adverse-effect level (LOAEL), and the
no-observed-adverse-effect level (NOAEL). The LOAEL is the
lowest exposure level at which there are statistically
significant increases in adverse effects in an exposed animal
population. The NOAEL is the highest exposure level at which
there are no demonstrated adverse effects in an exposed animal
population. Uncertainty factors are applied to the MOAELs or
reflect the revised RfD for manganese. The summary risk
calculations presented in Tables 6 through 8 of this ROD do
reflect the revised RfD for manganese.
22
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LOAELs to adjust for data limitations and for differences between
the exposure conditions of laboratory animals and human exposure
situations. The resulting RfD, expressed in units of mg/kg/day,
can be compared to the estimated human intakes of chemicals from
environmental media in order to evaluate the potential for
adverse health effects. The RfOs for the contaminants of
potential concern at the Woodlawn Landfill Site are presented in
Table 4.
6.2.3 Risk Characterization
The risk characterization combines the dose (or GDI) and the
toxicity value to generate a numerical value for risk. There are
several differences between the approach used to describe risk
for carcinogens and noncarcinogens. Both approaches are
summarized below.
6.2.3.1 Carcinogenic Risks
For carcinogens, risks are estimated as the incremental
probability of an individual developing cancer over a lifetime as
a result of exposure to the carcinogen. Excess lifetime
carcinogenic risk is calculated by multiplying the dose (GDI) by
the cancer slope factor. Carcinogenic risk estimates for each
chemical and each exposure pathway may be added together to
determine the aggregate risk associated with exposure to multiple
contaminants in multiple media. These risks are probabilities
that are generally expressed in scientific notation (e.g.,
1 X 10"6). An excess lifetime carcinogenic risk of 1 X 10~6
indicates that, as a plausible upper bound, an individual has a
one in one million chance of developing cancer as a result of
exposure to Site-related contaminants over a 70-year lifetime
under the specific exposure conditions at the Site.
Table 6 presents a summary of current carcinogenic risk estimates
for the exposure of adult and child receptors to ground water
containing all of the chemical constituents that were found in
each of 13 residential wells sampled during the RI. The total
cancer risk associated with exposure to residential well water
via each of the identified exposure routes (ingestion, inhalation
and dermal contact) is 1.6 X 10"4 for adults and 1.0 X 10'4 for
children. The majority of the risk is attributed to beryllium,
arsenic and vinyl chloride. However, as noted in Section 5.2.2,
above, the beryllium detected in the domestic well samples may be
the result of laboratory contamination. When beryllium is
eliminated from the risk calculations, arsenic and vinyl chloride
contribute 90 and 8.3 percent, respectively, of the total adult
cancer risk of 4.6 X 10~5 associated with exposure to residential
well water.
The total cancer risks for a child receptor exposed to surface
soils in the general landfill area (1.0 X 10~6) and for adult and
23
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child receptors exposed to surface soils of the former drain
field (3.5 X 10'6 and 1.7 X l(T6, respectively) fall within EPA's
target risk range of 1 X 10~6 to 1 X 10~4. The total cancer risk
associated with exposure to each of the other environmental media
evaluated at the Site is less than 1 X 10~6. Summary risk tables
for each of the media evaluated in the Risk Assessment can be
found in the RI Report.
Table 7 provides a summary of the total cancer risk estimates
that are based on potential current exposure of adult and child
receptors to Site contaminants through all of the pathways
(ground water, surface water, sediments and surface soils except
drain field surface soils) that were evaluated in the Risk
Assessment. A comparison of the risk estimates in Tables 6 and 7
underscores the fact that contaminated ground water is the
primary medium of concern at the Site.
As discussed above, the risks associated with potential future
exposure to Site contaminants were evaluated in addition to the
risks associated with current exposure. Table 8 presents a
summary of carcinogenic risk estimates for exposure of adult and
child receptors to contaminated ground water for three
hypothetical future use scenarios: (1) exposure to contaminants
currently present in ground water beneath the landfill property,
assuming a public water supply well is placed in the center of
the contaminant plume (existing conditions scenario); (2)
exposure to ground water contaminated with the highest levels of
vinyl chloride that, with the aid of a model, were predicted to
occur in the aquifer beneath the landfill property (on-site) and
beyond the property boundary (off-site) 70 years in the future,
assuming water supply wells are placed in the portions of the
aquifer that are expected to be most highly contaminated at that
time (modeled scenario); and (3) exposure to ground water
containing levels of contaminants that were predicted to occur in
ground water beneath the landfill property as a result of future
leaching from Cell B/C wastes, assuming a water supply well is
placed on the landfill property in the leachate-contaminated
ground water (leachate scenario).
The future cancer risks for adult and child receptors potentially
exposed to the existing concentrations of the chemicals in the
aquifer immediately below the landfill are 5.8 X 10"3 and 4.0 X
10~3, respectively. The chemicals in on-site ground water that
contribute most to this total cancer risk are vinyl chloride,
benzo(a)pyrene, benzo(b)fluoranthene, arsenic and 1,2-
dichloroethane. Vinyl chloride and benzo(a)pyrene represent 53
and 35 percent, respectively, of the total adult cancer risk of
5.8 X 10"3.
The future cancer risks for adult receptors exposed to ground
water containing the highest levels of vinyl chloride that were
predicted to occur in the aquifer 70 years in the future are 1.5
24
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X 10~2 for on-site receptors and 1.8 X 10"3 for off-site
receptors.
The cancer risks associated with potential future exposure to on-
site leachate-contaminated ground water are 7.8 X 10~2 for an
adult receptor and 5.8 X 10~2 for a child receptor. Nearly 100
percent of the risk is attributed to vinyl chloride.
6.2.3.2 Koncarcinoqenic Risks
The potential for adverse noncarcinogenic health effects as a
result of exposure to a single contaminant in a single medium is
expressed as the hazard quotient (HQ), or the ratio of the
estimated daily intake of a contaminant in a given medium to the
contaminant's reference dose. The hazard index (HI) is obtained
by adding the HQs for all of the contaminants in a medium or
across all media to which a given population may reasonably be
exposed. The HI provides a useful reference point for gauging
the potential significance of multiple contaminant exposures
within a single medium or across media. HI values less than or
equal to 1.0 indicate that lifetime exposure has limited
potential for causing an adverse effect in sensitive populations.
HI values greater than 1.0 show that acceptable levels of intake
have been exceeded.
Table 6 presents the chronic hazard index estimates for exposure
of adult and child receptors to ground water containing
contaminants found in residential wells adjacent to the Site.
The HI values exceeded 1.0 for both children (2.6) and adults
(2.3). Manganese is the contaminant with the highest
noncarcinogenic risk for this pathway, with a HQ of 2.0 for
children and 1.8 for adults.
The HI values associated with exposure to contaminants in the
other environmental media evaluated at the Site are less than
1.0, indicating that lifetime exposure to these media is not
expected to result in adverse noncarcinogenic health effects in
the exposed populations. Summary risk tables for each of the
media evaluated in the Risk Assessment are included in the RI
Report.
Table 7 presents a summary of the chronic hazard index estimates
for exposure of adult and child receptors to all of the
contaminated media (ground water, surface water, sediments and
surface soils except drain field surface soils) that were
evaluated in the Risk Assessment. A comparison of the HI values
in Tables 6 and 7 again demonstrates that contaminated ground
water is the medium of concern at the Site.
Table 8 presents a summary of the chronic hazard index estimates
for exposure of adult and child receptors to contaminated ground
water for two of the hypothetical future use scenarios described
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in Section 6.2.3.1, above. (Noncarcinogenic risks were not
assessed for the modeled scenario since the noncancer health
effect for vinyl chloride is negligible compared to the cancer
risk and, therefore, no reference dose is available for vinyl
chloride.)
The HI values for child and adult receptors potentially exposed
to the existing concentrations of the chemicals in the aquifer
immediately below the landfill are 59 and 50, respectively.
Manganese is the contaminant with the highest noncarcinogenic
risk for this potential future pathway, with a HQ of 56 for
children and 48 for adults.
The HI values associated with potential future exposure to on-
site leachate-contaminated ground water are less than 1.0.
6.3
Potential risks to nonhuman biological receptors were evaluated
in the Ecological Risk Assessment which is included in the RI
Report.
No critical habitats, endangered species or endangered species
habitats have been identified in the Site area. However,
wetlands occupy limited areas of the Site as discussed in Section
5.1, above. In addition, a tributary of Basin Run crosses the
southern end of the Site.
As discussed in Section 5.2.7, above, several metals were found
in downstream surface water samples collected from the unnamed
creek that flows across the Site. Levels of aluminum, copper,
lead and silver were found to exceed federal ambient water
quality criteria for the protection of aquatic life.
Levels of mercury found in soil above the former drain field of
the Transfer Station septic system exceed the l mg/kg soil
criterion that EPA has determined is protective of ecological
receptors at the Site, and may cause sublethal effects in area
birds that feed on exposed earthworms.
Levels of cadmium and zinc found in on-site seep sediments also
exceed criteria that EPA has determined are protective of
ecological receptors at the Site. The levels of cadmium found in
the sediments may cause sublethal effects in area predators as a
result of bioaccumulation. Levels of zinc present in the seep
sediments may inhibit plant growth.
6.4 Conclusion
Actual or threatened releases of hazardous substances from this
Site, if not addressed by implementing the response action
selected in this ROD, may present an imminent and substantial
26
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endangerment to public health, welfare, or the environment.
7.0 REMEDIAL OBJECTIVES AMP CLEANUP LEVELS
The overall remedial objectives for the Site are: (l) to prevent
exposure to contaminated ground water; (2) to prevent migration
of contaminants from the landfill and PVC sludge disposal cells
to ground water and surface water; (3) to restore ground water to
its beneficial use; (4) to prevent exposure to the contents of
the landfill and the PVC sludge disposal cells, and contaminated
soils and sediments; and (5) to control landfill gas to ensure
protection of human health and the environment.
7.1 Remedial Objectives and Cleanup Levels for Ground Water
The Risk Assessment indicates that the carcinogenic and
noncarcinogenic risks associated with exposure to contaminated
ground water at the Site exceed acceptable levels and therefore
warrant remedial action to clean up ground water at the Site.
Ordinarily, MCLs and non-zero Maximum Contaminant Level Goals
(MCLGs) would be used as cleanup levels for ground water. At
this Site, however, because there are multiple contaminants, the
cumulative carcinogenic risk associated with MCLs for those
contaminants exceeds 1 X 10~4. In addition, the hazard index
associated with MCLs and MCLGs for Site ground water contaminants
is greater than 1.0. Under such circumstances, risk- or health-
based levels are used to develop cleanup levels. Risk-based
cleanup levels are levels that would result in a cumulative
carcinogenic risk within EPA's target risk range of 1 X 10~4 to
1 X 10~°; health-based cleanup levels correspond to a HI of 1.0
or less. Occasionally, calculated risk- and health-based
concentrations are found to be lower than background levels, or
below the levels that can actually be detected or accurately
measured in the laboratory. When these situations arise, EPA may
also take background conditions, or Practical Quantitation Limits
and Instrument Detection Limits into account when establishing
cleanup levels.
The following remedial objectives and cleanup levels were
developed for ground water at the Site based on the
considerations outlined above:
1. Prevent exposure to ground water that contains Site-
related contaminants at concentrations that exceed the
cleanup levels presented in Tables 9 and 10, until the
ground water cleanup levels are achieved.
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2. Remediate ground water in the area of attainment4 so
that: (a) the levels of contaminants with carcinogenic
health effects do not exceed the ground water cleanup levels
presented in Table 9; and (b) the levels of contaminants
with noncarcinogenic health effects (presented in Table 10)
do not exceed MCLs, non-zero MCLGs, or levels that would
result in an aggregate HI greater than 1.0. As noted in
Tables 9 and 10, EPA will take background levels of arsenic
and manganese into account in determining whether the
remediation objectives have been achieved.
7.2 Remedial Objectives and Cleanup Levels for Wastes
Some form of control of the wastes in PVC sludge disposal Cell
B/C (and Cell A, if found) is necessary in order to ensure that
leachate generation does not result in an exceedance of the
ground water cleanup levels. In order to evaluate treatment
options for this material, a cleanup level was developed for
these wastes based on the Summers model. The results of the
Summers model indicated that technologies for treatment of the
waste must meet a treatment standard (cleanup level) of 7.7
micrograms of vinyl chloride per kilogram of waste in order to
sufficiently reduce the concentration of contaminants in the
leachate that could be derived from the PVC sludge.
Alternatively, waste containment technologies must be designed to
minimize the infiltration of rainwater and resulting leachate
generation.
7.3 Remedial Objectives and Cleanup Levels for Soils
Levels of mercury in the soils above the former drain field of
the Transfer Station septic system are above normal background
levels and may provide an opportunity for mercury 'to enter the
food chain via exposure of soil organisms to the contaminated
soils. EPA has determined that a soil mercury concentration of
1 mg/kg is the cleanup level that would be protective of
ecological receptors at this Site. Alternatively, waste
containment technologies must be designed to prevent exposure of
ecological receptors to soils contaminated with mercury in excess
of this level.
8.0 DESCRIPTION OF ALTERNATIVES
The Feasibility Study prepared by IT (April 1993) evaluated six
alternatives to address the risks posed by current and potential
future exposure to contaminants at the Woodlawn Landfill Site.
Alternative l provides no remediation, monitoring or controls,
4 The area of attainment is defined as the area outside the
boundary of any waste remaining in place up to and including the
boundary of the contaminant plume.
28
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but was retained as a baseline for comparison with other
alternatives. Alternatives 2 and 3 are considered limited action
since they include monitoring, institutional controls and
measures to eliminate exposure to contaminated ground water and,
in the case of Alternative 3, a landfill cap in order to comply
with State landfill closure requirements. Alternative 4 provides
active remediation of contaminated ground water. Alternatives 5
and 6 offer two options, in addition to capping, for addressing
PVC sludge disposal Cell B/C and Cell A, if found: on-site
treatment and off -site disposal, respectively.
COMMON
Alternatives, 2 through 6, which are described in greater detail
below, include several common elements. First, each of these
alternatives provides for construction of a perimeter security
fence around the landfill property boundary in order to secure
the Site from unauthorized access and usage.
Second, each of Alternatives 2 through 6 calls for the
institution of landfill property deed restrictions and area
ground water use restrictions as necessary to prevent exposure to
contaminated ground water and wastes and to ensure that the
alternative may be effectively implemented.
Third, each of Alternatives 2 through 6 includes regular
monitoring of ground water, the unnamed creek and landfill gas.
The monitoring programs include the following activities:
installation of three or four new monitoring wells around the
perimeter of the landfill; quarterly sampling of nine to eleven
monitoring wells and six domestic wells during the post-
construction remediation phase; quarterly sampling of surface
water and sediments from four or five locations in the unnamed
creek during the post-construction remediation phase;
installation of a network of nested soil-gas probes at
approximately 53 locations around the perimeter of the landfill;
and quarterly collection of gas samples from each of the soil-gas
probes. The monitoring costs associated with each alternative
are based on these assumptions. Final determination of the
specific number and location of monitoring points, the frequency
and duration of sampling, and the analytical parameters and
methods to be included in the monitoring program, will be made by
EPA, in consultation with MDE,5 during the remedial design and,
5 In accordance with 40 C.F.R. S 300.5l5(h)(3) in Subpart F
of the NCP, the phrase "EPA, in consultation with MDE" when used
in this ROD means that EPA (the lead agency) shall provide MDE
(the support agency) an opportunity to review and comment on the
remedial design and any proposed determinations on potential
applicable or relevant and appropriate requirements (ARARs) or
criteria, advisories or guidance "to be considered" (TBCs).
29
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as appropriate, during implementation of the selected remedy.
Fourth, each of Alternatives 2 through 6 provide for an alternate
water supply at residences where Site-related contaminants are
determined to be present in domestic well water at concentrations
that exceed the ground water cleanup levels presented in Tables 9
and 10. The costs for maintaining the well water treatment
system at parcel 309 were included in the cost figures for
Alternatives 2 through 6. However, the costs for installation
and maintenance of additional treatment systems were not included
in the cost estimates.
Finally, Alternatives 2 through 6 provide for interim monitoring
of select residential wells. Because of the potential public
health risk posed by contaminated ground water at the Site, EPA
required annual monitoring of seven residential wells to begin
prior to the post-construction remediation phase (interim
monitoring). Interim monitoring began in May of 1993 and would
continue under Alternatives 4 through 6 until the post-
construction quarterly ground water monitoring program begins.
If determined to be necessary by EPA, in consultation with MDE,.
the number and location of residential wells in the interim :
monitoring program and the frequency of monitoring shall be
modified. The costs for the interim monitoring program were not
included in the cost figures for Alternative 2 through 6.
COST EVALUATIONt
The cost evaluation of each alternative includes consideration of
capital costs and annual operation and maintenance costs (O&M).
A present worth analysis is also included, allowing all remedial
action alternatives to be compared on the basis of a single
figure. A discount factor of ten percent and a zero percent
inflation factor were used in the analysis and a 30-year
monitoring and maintenance period was assumed for cost estimating
purposes. All costs and implementation time frames provided for
the alternatives below are estimates and should be used for
comparative purposes only. The actual duration of the monitoring
and maintenance period will be determined by EPA, in consultation
with MDE, based on the results of environmental monitoring and
statutory five-year reviews.
The following is a brief summary of each of the alternatives
evaluated for remediation of the Site.
Alternative l: No Action
Capital Costs: 0
Annual O6M Costs: 0
Present Worth: 0
Years to Implement: 0
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The NCP requires that the "no action11 alternative be evaluated at
every site as a baseline for comparison with other alternatives.
This alternative provides no remediation (other than what might
occur through naturally-occurring processes), monitoring or
security activities at the site. This alternative would not
prevent or eliminate exposure to contaminated ground water in
residential wells and would allow continued migration of
contaminants from source areas into ground water and surface
water.
Alternative 2: Monitoring/ Deed and Ground Water Use
Restrictions (Institutional Controls),
Perimeter Fencing, Treatment at Impacted
; Residential wells
Capital Costs: $562,000
Annual O&M Costs: $514,000
Present Worth: $4,436,000
Years to Implement: 3
In Alternative 2, deed restrictions would be implemented to limit
the future use and development of the landfill property. In
addition, ground water use restrictions, which are currently in
effect, would continue to be enforced and modified as necessary
to prevent exposure to contaminated ground water and to ensure
that the selected remedy could be effectively implemented.
A security fence would be erected around the perimeter of the
landfill property boundary (parcel 267), excluding the Transfer
Station building and rear loading area, in order to secure the
Site against unauthorized access. Bare areas of the landfill
surface would be revegetated in order to facilitate maintenance
of the existing landfill cover material.
Alternative 2 includes no action to remediate ground water or to
eliminate future contamination of ground water. Constituents of
wastes and soils would continue to leach into ground water,
contaminant levels in the ground water would continue to exceed
the cleanup levels, and contaminated ground water would continue
to migrate downgradient. However, ground water and stream
sampling and analysis would be conducted until the ground water
contaminant concentrations were reduced to acceptable levels as a
result of natural attenuation.
As previously mentioned, ground water sampling and analysis would
be performed for certain existing monitoring wells and new wells
would be installed in conformance with Code of Maryland Annotated
Regulation (COMAR) 26.04.04. Samples from select residential
wells would also be analyzed. Ground water elevation, pH,
temperature and conductivity measurements would be recorded for
each sampling period. Ground water samples would be analyzed for
volatile and semivolatile organic compounds, pesticides and
metals.
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Wellhead treatment or a replacement well would be provided at any
residence where Site-related contaminants were determined to be
present in domestic well water at concentrations that exceed the
ground water cleanup levels presented in Tables 9 and 10. The
objective of the wellhead treatment would be to reduce the
concentrations of contaminants to the ground water cleanup
levels. The type of wellhead treatment system to be used would
depend on the contaminants found during monitoring. Zeolite
filters or ion-exchange resins would remove inorganic
contaminants, including manganese, from the household water
supplies. Carbon adsorption units have been shown to be
effective in removing VOCs. Air stripping units are also
commercially available for VOC removal for residential
applications. Alternatively, a replacement well would be
required to provide a sufficient quantity of water that meets the
ground water cleanup levels. EPA, in consultation with MDE,
would determine the choice of alternate water supply and the
exact components and configuration of the wellhead treatment
system during the remedial design.
Residual wastes from the wellhead treatment units in the form of
spent carbon or filtration media would be evaluated in accordance
with the hazardous waste identification requirements of 40 C.F.R.
§ 261.24, COMARs 10.51.02.10, .11 and .12 (1985), and COMARs
26.13.02.11, .12 and . 13.6 On-site handling of any residual
wastes found to exhibit a characteristic of a hazardous waste
would comply with standards applicable to generators of hazardous
waste (COMARs 10.51.03.01, .03, .04, .05 and .06 [1985], and
COMARs 26.13.03.01, .03, .04, .05, .06 and .08) and transporters
of hazardous waste (COMARs 10.51.04.01, .02, .03 and .04 [1985],
and COMARs 26.13.04.01, .02, .03 and .04). The federal land
disposal restrictions contained in 40 C.F.R. Part 268 would also
apply to any off-site disposal of residual wastes found to
exhibit a characteristic of a hazardous waste. As previously
noted, the costs for provision of an alternate water supply and
disposal of treatment residuals were not included in the cost
figures listed above for this alternative.
Surface water and sediment samples would be collected from
upstream and downstream locations in the unnamed creek. These
samples would be analyzed for volatile and semivolatile organic
compounds, pesticides and metals. In addition, surface water
6 The 1985 Maryland regulations cited in this ROD are the
federally-authorized Resource Conservation and Recovery Act
(RCRA) regulations. These regulations have been subsequently
amended by the State of Maryland and recodified in Title 26,
Subtitle 13, of the Code of Maryland Regulations (COMARs). Where
the 1985 regulations appear in this ROD, the Title 26 COMARs are
cited after them. A copy of the 1985 Maryland regulations is
contained in the Administrative Record.
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parameters such as temperature, dissolved oxygen, pH,
conductivity and flow rate would be measured at each sampling
station. Surface water samples from each station would also be
analyzed for total suspended solids, alkalinity and hardness.
Similarly, the temperature, oxidation-reduction potential (Eh),
pH, conductivity and color (as determined by comparison with the
Munsell Soil Color Charts) of sediments at each sample location
would be measured. Sediment samples from each sampling location
would also be analyzed for total organic carbon, grain size,
percent moisture and percent solids. Biological monitoring of
aquatic macroinvertebrates would be conducted twice a year for
the first year of monitoring and once a year thereafter.
Several criteria would be used to evaluate the stream monitoring
data and assess the need for additional remedial action to
address any adverse Site-related impacts on the stream. The
criteria for surface water include upgradient stream conditions,
State water quality standards and federal ambient water quality
criteria. For sediments, Apparent Effects Thresholds (AETs) and
National Oceanic and Atmospheric Administration (NOAA) Biological
Effects Range - Low (ER-L) values would be considered in
interpretation of the monitoring data. Methods described in
EPA's guidance document, Rapid Bioassessment Protocol for Use in
Streams and Rivers: Benthic Macroinvertebrates and Fish1
(EPA/444/4-89-001, May 1989), would also be used to detect the
existence and characterize the severity of potential Site-impacts
on the unnamed creek that crosses the Site.
In order to evaluate potential off-site migration of landfill
gas, a network of nested soil gas monitoring probes would be
installed around the landfill near the Site boundary. Gas
samples would be collected on a quarterly basis and analyzed for
VOCs and methane. EPA, in consultation with MDE, would evaluate
the monitoring results in order to determine the need for further
actions to protect the health and safety of surrounding residents
(e.g., installation of a perimeter passive-gas collection
system).
The costs listed above are based on quarterly monitoring of
ground water, including the water in domestic wells, and the
unnamed creek. However, EPA, in consultation with MDE, could
determine that the sampling frequency should be decreased at the
end of a one- or two-year period to semiannual or annual sampling
if measured concentrations remained below the ground water
cleanup levels or stream action levels and no upward trends in
the concentrations of contaminants of concern were observed
between sampling events.
7 This guidance document was developed for streams in the
Appalachian Plateau region. If necessary, EPA would adjust the
methods prescribed therein for local conditions.
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Alternative 3: Excavation of Drain Field Soils, Capping,
Monitoring, Institutional controls, Perimeter
Fencing, Treatment at contaminated Residential
wells
Capital Costs: $17,712,000
Annual O&M Costs: $538,000
Present Worth: $15,856,000
Years to Implement: 5
All of the elements described in Alternative 2, with the
exception of the revegetation of the existing landfill cover,
would also be included in Alternative 3. Alternative 3 would not
provide any action to remediate ground water but would provide
physical containment of the source materials.
Capping of the source areas under this alternative would minimize
the amount of precipitation that may infiltrate into waste
materials and soils and mobilize constituents therein. Capping
would also create a physical barrier that would prevent contact
of ecological receptors with contaminated surface soils and seep
sediments.
Prior to installation of the cap, approximately 400 cubic yards
of mercury-contaminated surface soils would be tested and
excavated from the abandoned septic system drain field. If the
soils did not exhibit the characteristic of toxicity as defined
in 40 C.F.R. S 261.24, they would be consolidated near the center
of the landfill. If the soils did exhibit the toxicity
characteristic, they would be disposed of at an off-site Resource
Conservation and Recovery Act (RCRA) hazardous waste (Subtitle C)
disposal facility. On-site handling of any such hazardous wastes
would be in compliance with standards applicable to generators of
hazardous waste (COMARs 10.51.03.01, .03, .04, .05 and .06
[1985], and COMARs 26.13.03.01, .03, .04, .05, .06 and .08) and
transporters of hazardous waste (COMARs 10.51.04.01, .02, .03 and
.04 [1985], and COMARs 26.13.04.01, .02, .03 and .04). The
federal land disposal restrictions contained in 40 C.F.R. Part
268 would also apply to the off-site disposal of any soils found
to exhibit the toxicity characteristic.
The currently-operating septic system drain field, located west
of the Transfer Station, would be relocated in order to eliminate
any flow of water from the septic system into areas where PVC
sludge and other wastes were placed.
A cap would be placed over the landfill and identified cells of
PVC sludge. It would consist, from the bottom up, of a prepared
subbase, gas collection zone, low permeability layer, drainage
layer, cover material, topsoil and a vegetative layer. The total
area to be capped would be approximately 31 acres. The cap
specifications would be consistent with the single-barrier cap
34
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requirements presented in the EPA Municipal Landfill Guidance and
would meet or exceed the landfill closure cap requirements
specified in COMARs 26.04.07.21 B and E.
Predesign studies would be conducted in order to delineate the
boundaries of the fill material, including the boundaries of PVC
sludge disposal Cells A and B/C. The actual areal extent of the
cap will be based on the data gathered during the RI and
predesign studies and will be determined by EPA, in consultation
with HDE, during the design phase.
Both passive and active gas collection systems were evaluated as
components of the cap in the FS. The primary function of a
passive system is to provide a mechanism for the release of
landfill gases to the atmosphere in order to minimize potentially
dangerous conditions due to gas buildup beneath the cap. An
active gas collection system would prevent the buildup of gases
beneath the cap and control emissions of landfill gases to the
atmosphere. Additional studies would be performed prior to the
design of the cap in order to determine landfill gas constituents
and the rate of emissions. Based on the results of these
studies, EPA, in consultation with MDE, would determine during
the design phase whether an active gas collection system is
required in order to comply with the substantive portions of
State requirements governing air quality (COMARs 26.11.06.02,
.03, .06, .08 and .09; COMAR 26.11.15; and COMAR 26.11.19.02 G)
or in order to protect human health, welfare, or the environment.
The cost figures above reflect estimates for installation of a
passive gas collection system. The capital cost of an active gas
collection and treatment system would be approximately $1.6
million, about $800,000 more than the cost of the passive system.
The annual O&M costs associated with the active collection system
would be approximately $850,000, assuming the gas would be
thermally treated in flarestacks.
The low permeability layer of the cap would consist of two feet
of clay with a permeability less than or equal to 1 X 10"7
centimeters per second (cm/sec) or a synthetic liner that is
equally protective, as determined by EPA, in consultation with
MDE, during the remedial design. For cost-estimating purposes,
the low permeability layer was assumed to consist of two feet of
clay with a permeability of 1 X 10~7 cm/sec.
A drainage layer would be constructed immediately above the low
permeability layer to collect water that percolates through the
soil cover. The drainage layer would consist of natural
materials (e.g., sand with a permeability equal to or greater
than 10~2 cm/sec) or a synthetic, high permeability geonet
"sandwiched1* between layers of filter fabric which would inhibit
the migration of fine soil particles into the flow area of the
geonet. This highly permeable layer would divert percolated
35
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water away from the clay layer to a network of slotted or
perforated collection pipes. The pipes would, in turn, convey
the percolated water to drainage ditches along the edges of the
cap.
An 18-inch-thick layer of cover material would be installed above
the drainage layer. Six inches of topsoil would be placed on the
surface of the cover material. A vegetative layer would be
established on the completed cap.
Alternative 4: Excavation of Drain Field soils, Capping, Ground
Water Extraction aad Treatment, Monitoring,
Institutional Controls, Perimeter Fencing,
Wellhead Treatment at Contaminated Residential
wells
Capital Costs: $20,997,000
Annual O&M Costs: $1,609,000
Present Worth: $23,826,000
Years to Implement: 6
The monitoring program, institutional controls and perimeter
fencing described for Alternative 2 and the soil excavation and
cap described for Alternative 3 would also be included in
Alternative 4. In addition, Alternative 4 would provide
remediation of contaminated ground water.
An estimated 40 extraction wells would be installed in the area
of Cell B/C and around the perimeter of the landfill in order to
effectively capture the plume and to withdraw ground water until
the concentrations of contaminants remaining in the ground water
no longer exceed the ground water cleanup levels. The extracted
ground water would be treated on-site to reduce contaminant
levels to concentrations that are protective of surface water
quality, and would be discharged to the stream at the southern
end of the landfill property.
The approximate locations of the ground water extraction wells
are shown in Figure 4. The well configuration shown in Figure 4
is preliminary and may be further refined during remedial design.
The estimated peak flow rate of the ground water recovery system
would be 200 gallons per minute. The actual flow rate of
extracted ground water would be expected to decrease
significantly with time.
It is expected that the concentration of vinyl chloride in ground
water would decrease to the 1 nq/L cleanup level within the area
of attainment after 12 years of operation of the ground water
recovery system. However, ground water extraction and treatment
would continue until the ground water cleanup levels were
achieved for all contaminants identified in Tables 9 and 10,
including semivolatile organic compounds and metals. As noted in
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Tables 9 and 10, EPA will take background levels of arsenic and
manganese into account in determining whether the ground water
remedial objectives have been achieved. EPA, in consultation
with MDE, will determine background levels of arsenic and
manganese at the Site during the remedial design, based on the
results of a predesign study.
Extracted ground water would be treated on-site in a three-step
process. The first step would entail precipitation and
flocculation/coagulation to remove manganese and other inorganic
contaminants. A treatability study would be performed before
final design of the treatment system in order to optimize
conditions for removal of metals. In the second step, the
filtered effluent from the precipitation unit would be piped to
an air stripper column for removal of VOCs. Finally, the ground
water discharged from the air stripper would be passed through
granular activated carbon to remove semivolatile organic
compounds and any remaining contaminants. The treated ground
water would then be discharged to the stream that crosses the
southern end of the Site. Discharge limitations would be
developed based on State water quality standards (COMARs
26.08.02.03-.03-3), federal ambient water quality criteria
established pursuant to Section 304 of the Clean Water Act, 33
U.S.C. § 1314, which apply to the protection of aquatic life,
MCLs and non-zero MCLGs. The discharge would also comply with
substantive portions of State and Clean Water Act requirements
pertaining to point source discharges to surface water, including
discharge limitations (Section 402 of the Clean Water Act, 33
U.S.C. S 1342; COMARs 26.08.03.01 and .07), standards for best
management practices (40 C.F.R. Part 125, Subpart K), and test
procedures (40 C.F.R. Part 136).
Potential impacts to human health from the air stripper which
would be used to treat contaminated ground water were evaluated
in the FS. The maximum predicted air emission rate of vinyl
chloride from the air stripper was estimated to be 4.5 X 10~3
pounds per hour (5.7 X 10~* grams per second [g/sec]). However,
the emission rate is expected to decline as ground water
remediation progresses. Based on current projections regarding
the progressive reduction in the vinyl chloride concentration
over time, an average annual vinyl chloride emission rate of 6.2
pounds per year (8.9 X 10~5 g/sec) was predicted. Using the
methods prescribed in Screening Methods for the Development of
Air Toxics Emission Factors (EPA-450/4-91-021, September 1991)
and preliminary information regarding the location of the
proposed air stripper, and assuming a vinyl chloride air emission
rate of 8.9 X 10"s g/sec, a maximum hourly vinyl chloride
concentration of 0.27 Mg/m3 was projected in the ambient air at
the location of the nearest residential receptor.
The estimated excess lifetime cancer risk for a child exposed to
this level of vinyl chloride in ambient air over a 12-year period
37
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(the estimated time frame for attainment of the ground water
cleanup levels for vinyl chloride) is 5.8 X 10~7. This
incremental cancer risk estimate does not exceed the l X 10~6
lower limit of EPA's target risk range. However, the estimate
does not include incremental risk associated with exposure to
emissions of VOCs other than vinyl chloride. In addition, the
assumptions used to calculate this risk may not remain valid if
conditions at the Site or design considerations change prior to
remedy design and implementation. Therefore, air emission and
dispersion modeling and a long-term exposure evaluation would be
performed during the predesign phase in order to better define
potential risk to human health resulting from exposure to VOC
emissions from the air stripper.
Emission controls would be provided if EPA, in consultation with
MOE, determined that emissions from the air stripper stack could
result in an excess lifetime cancer risk greater than 1.0 X 10~6
for exposed individuals. Air emission controls would also be
provided if necessary to comply with State regulations pertaining
to toxic air pollutants (COMAR 26.11.15), federal air emission
standards for process vents (40 C.F.R. Part 264, Subpart AA), or
State requirements pertaining to emission of VOCs (COMAR
26.11.06.06). The EPA guidance document, Control of Air
Emissions from Superfund Air Strippers at Superfund Groundvater
Sites (OSWER Directive 9355.0-28, June 15, 1989), would also be
considered in determining the need for air emission controls.
The costs for evaluating potential human health impacts from
exposure to air emissions from the stripper column and for
providing emission controls were not included in the cost figures
listed above for this alternative.
The treatment of ground water under Alternative 4 may result in
the generation of residual wastes. Any residual wastes would be
evaluated in accordance with the hazardous waste identification
requirements of 40 C.F.R. S 261.24, COMARs 10.51.02.10, .11 and
.12 (1985), and COMARs 26.13.02.11, .12 and .13. On-sitc
handling of any residual wastes found to exhibit a characteristic
of a hazardous waste would comply with standards applicable to
generators of hazardous waste (COMARs 10.51.03.01, .03, .04, .05
and .06 [1985], and COMARs 26.13.03.01, .03, .04, .05, .06 and
.08) and transporters of hazardous waste (COMARs 10.51.04.01,
.02, .03 and .04 [1985], and COMARs 26.13.04.01, .02, .03 and
.04). The federal land disposal restrictions contained in 40
C.F.R. Part 268 would also apply to any off-site disposal of
residual wastes found to exhibit a characteristic of a hazardous
waste.
Some uncertainty exists as to whether ground water collection
will significantly reduce the concentrations of contaminants in
ground water. Increased flow velocities caused by pumping may
not allow enough time for contaminants in ground water and soil
in the saturated zone to reach equilibrium. The desorption of
38
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contaminants from the aquifer soils may be the rate-limit ing step
in contaminant removal from the aquifer. In order to overcome
this potential problem, pulsed pumping may have to be employed to
promote equilibration between contaminants in soils and ground
water so that contaminants may be more effectively removed from
the aquifer. Aquifer tests would need to be performed during
remedial design, and possibly during the remedial action, in
order to optimize recovery of contaminants with a pulsed pumping
system. The pumping rates and other operational considerations
associated with the ground water collection system would be
determined by EPA, in consultation with MDE, during the remedial
design phase.
Alternative 5: Excavation of Drain Field Soils, Excavation and
On-site Low Temperature Thermal Treatment of PVC
Sludge, capping, Ground Water Extraction and
Treatment, Monitoring, Institutional Controls,
Perimeter Fencing, Wellhead Treatment at
Contaminated Residential Wells
Capital Costs: $35,372,000
Annual O&M Costs: $1,609,000
Present Worth: $30,902,000
Years to Implement: 7
All elements of Alternative 4 would also be included in
Alternative 5. Alternative 5 would provide institutional
controls, perimeter fencing, ground water extraction and
treatment, monitoring, soil excavation, and a cap over the
landfill and PVC sludge disposal cells. In addition,
approximately 36,000 cubic yards of PVC sludge and contaminated
soils would be excavated from Cell B/C and Cell A (if found) and
treated on-site using low temperature thermal desorption.
The sludge treatment process would comply with federal standards
for air emissions from process vents (40 C.F.R. Part 264, Subpart
AA) and the requirements for thermal treatment of hazardous waste
(40 C.F.R. Part 264, Subpart X, and 40 C.F.R. Part 265, Subpart
P). Samples of the treated material would be analyzed to ensure
attainment of cleanup levels. The treated sludge would be
backfilled into the excavated cell area if the material did not
exhibit any of the characteristics of hazardous waste as defined
in 40 C.F.R. $ 261.24, COMARs 10.51.02.10, .11 and .12 (1985),
and COMARs 26.13.02.11, .12 and .13.
The total time required for treatment of the waste is estimated
at one-and-a-half to two years. Construction of the 31-acre cap
and installation of certain recovery wells would not begin until
the sludge treatment had been completed.
A preliminary treatability study was performed during the FS in
order to investigate the feasibility of treating the PVC sludge
39
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wastes using low temperature thermal desorption. Tests were run
over a range of temperatures extending from 125 to 700 degrees
Celsius. The test results indicated the formation and
persistence of chlorinated "daughter" products and other thermal
degradation products at certain temperatures. Further pilot-
testing would be required prior to implementation of this
alternative in order to optimize the design of the thermal
treatment unit.
The cost figures listed above do not include pilot-testing or the
treatment of Cell A wastes. It was not possible to determine the
volume of material in Cell A because no PVC sludge was found
during the RI in the area thought to be occupied by Cell A.
Alternative 6: Excavation of Drain Field Boils, Excavation and
Off-site Disposal of PVC Sludge, Capping, Ground
Water Extraction and Treatment, Monitoring,
Institutional Controls, Perimeter Fencing,
Wellhead Treatment at Contaminated Residential
Wells
Capital Costs: $41,253,000
Annual O&M Costs: $1,609,000
Present Worth: $37,135,000
Years to Implement: 7
All elements of Alternative 4 would also be included in
Alternative 6. Alternative 6 would provide institutional
controls, perimeter fencing, ground water extraction and
treatment, monitoring, and a cap over the landfill and PVC sludge
disposal cells. In addition, approximately 36,000 cubic yards of
PVC sludge and contaminated soils would be excavated from Cell
B/C and Cell A, if it is found, and transported to an off-site
landfill for disposal.
An industrial waste landfill was identified in York,
Pennsylvania, approximately 80 miles from Cecil County. The cost
estimate for this alternative is based on disposal of the PVC
sludge and contaminated soils at that landfill.
Testing conducted during the RI/FS indicates that the PVC sludge
in Cell B/C does not exhibit the characteristics of hazardous
waste as defined in 40 C.F.R. Part 261, Subpart C, and that this
material may be accepted by a RCRA industrial waste (Subtitle D)
landfill. However, the receiving facility may require additional
testing to verify the ability of the disposal facility to accept
the sludge and contaminated soils. In the event that future
analyses of excavated PVC sludge and contaminated soils indicates
that any portion of the material exhibits any characteristic of
hazardous waste as defined in 40 C.F.R. S 261.24, COMARs
10.51.02.10, .11 and .12 (1985), and COMARs 26.13.02.11, .12 and
.13, that portion of the material would have to be treated on-
40
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site or disposed of at an off-site RCRA hazardous waste (Subtitle
C) facility. On-site handling of any such hazardous wastes would
be in compliance with standards applicable to generators of
hazardous waste (COMARs 10.51.03.01, .03, .04, .05 and .06
[1985], and COMARs 26.13.03.01, .03, .04, .05, .06 and .08) and
transporters of hazardous waste (COMARs 10.51.04.01, .02, .03 and
.04 [1985], and COMARs 26.13.04.01, .02, .03 and .04). The
federal land disposal restrictions contained in 40 C.F.R. Part
268 would also apply to the off-site disposal of any soils found
to exhibit the toxicity characteristic.
Costs for on-site treatment of the PVC sludge, or disposal of the
PVC sludge at a RCRA hazardous waste (Subtitle C) facility, were
not included in the cost figures listed above for this
alternative. In addition, since sludge disposal Cell A could not
be found during the RI, costs for excavation and off-site
disposal of Cell A wastes were not included in the cost figures.
9.0 SUMMARY OF COMPARATIVE ANALYSIS OP ALTERNATIVES
The six remedial action alternatives described above were
compared against the nine evaluation criteria set forth in the
NCP, 40 C.F.R. S 300.430(e)(9). These nine evaluation criteria
can be categorized into three groups: threshold criteria,
primary balancing criteria, and modifying criteria. The criteria
associated with each category are as follows:
THRESHOLD CRITERIA
• Overall protection of human health and the environment
• Compliance with applicable or relevant and appropriate
requirements (ARARs)
PRIMARY BATANCING CRITERIA
Long-term effectiveness
Reduction of toxicity, mobility, or volume through
treatment
Short-term effectiveness
Implementability
Cost
MODIFYING CRITERIA
• Community acceptance
• Support agency acceptance
These evaluation criteria relate directly to requirements in
Section 121 of CERCLA, 42 U.S.C. S 9621, which determine the
overall feasibility and acceptability of the remedy. Threshold
criteria must be satisfied in order for a remedy to be eligible
for selection. Primary balancing criteria are used to weigh
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major trade-offs between remedies. Support agency and community
acceptance are modifying criteria which are taken into account
after public comment is received on the Proposed Plan.
The following discussion evaluates the six remedial alternatives
developed for the Woodlawn Landfill Site against the nine
criteria set forth in the NCP.
9.1 Overall Protection of
A primary requirement of CERCLA is that the selected remedial
action be protective of human health and the environment. A
remedy is protective if it reduces current and potential risks
associated with each exposure pathway at a Site to acceptable
levels.
Alternative 1 (No Action) contains no provisions for preventing
exposure to contamination, and is not protective of human health
and the environment. Although Alternative 2 includes measures
for preventing human exposure to unacceptable levels of Site
contaminants, Alternative 2 does not include capping, and would
not prevent exposure of ecological receptors to mercury-
contaminated soils and contaminated seep sediments. Therefore,
Alternative 2 would not be considered protective of the
environment. Since Alternatives 1 and 2 do not satisfy the
threshold criterion of protectiveness, they will not be
considered further in this analysis.
Alternatives 3 through 6 would provide adequate protection of
human health by preventing.exposure to contaminated ground water
through provision of an alternate water supply or point-of-entry
treatment and institution of ground water use restrictions.
Alternatives 3 through 6 would also inhibit migration of
contaminants into ground water through capping, which would
reduce the amount of precipitation that may infiltrate and
mobilize contaminants in the wastes, and prevent exposure of
ecological receptors to mercury-contaminated soils and
contaminated seep sediments.
Alternatives 3 through 6 call for monitoring of the stream that
crosses the Site, which would identify conditions that warrant
additional actions to protect aquatic life and comply with ARARs.
Alternatives 4 through 6 offer advantages over Alternative 3,
however, because they provide for active treatment of ground
water, which would minimize migration of contaminants and
diminish loading of contaminants to the stream.
Following the completion of the remedial action, the residual
risks for each of Alternatives 4, 5 and 6 would be the same
because each of these alternatives would achieve the same ground
water cleanup levels and prevent exposure to contaminated soils
and sediments.
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9.2 Compliance vith ARARs
This criterion addresses whether a remedy will meet all of the
applicable or relevant and appropriate requirements (ARARs) of
federal and state environmental laws and/or will provide grounds
for invoking a waiver.
The Maximum Contaminant Levels (MCLs) and non-zero Maximum
Contaminant Level Goals (MCLGs) for public drinking water
supplies established under the Safe Drinking Water Act, 42 U.S.C.
§§ 300f et sea.. are considered to be relevant and appropriate
standards for ground water cleanup under the Superfund program.
The concentrations of several contaminants in ground water
underlying the landfill property exceed MCLs. Since Alternative
3 would do nothing to reduce the concentration of these
contaminants, it would not result in compliance with this ARAR.
Therefore, it will not be considered further in this analysis.
Under Alternatives 4, 5 and 6, ground water would be extracted
and treated. These alternatives would ultimately comply with
MCLs and non-zero MCLGs for inorganic and organic chemicals
(40 C.F.R. SS 141.11-.12, 141.50-.51, and 141.61-.62). Health
Effects Assessments and U.S. EPA Health Advisories were
considered in establishing ground water cleanup levels for the
Site, and would be considered in evaluating the protectiveness of
Alternatives 4 through 6.
The treatment of ground water in Alternatives 4 through 6 would
result in VOC emissions from an air stripper to ambient air. Air
emission controls may be necessary in order to meet State and
federal requirements for air emissions from air strippers. These
requirements include State regulations pertaining to toxic air
pollutants, including the regulations that establish standards
for hazardous air pollutants (COMAR 26.11.15), federal air
emission standards for process vents (40 C.F.R. Part 264,
Subpart AA), and State requirements pertaining to emissions of
VOCs (COMAR 26.11.06.06). The EPA guidance document entitled
Control of Air Emissions from Superfund Air Strippers at
Superfund GroundVater Sites (OSWER Directive 9355.0-28, June 15,
1989) would be considered in assessing the need for controlling
air emissions from the air stripper.
The treatment of ground water in Alternatives 4 through 6 may
also result in the generation of residual wastes. Any residual
wastes would be evaluated in accordance with the hazardous waste
identification requirements of 40 C.F.R. S 261.24, COMARs
10.51.02.10, .11 and .12 (1985), and COMARs 26.13.02.11, .12 and
.13. On-site handling of any residual wastes found to exhibit a
characteristic of a hazardous waste would comply with standards
applicable to generators of hazardous waste (COMARs 10.51.03.01,
.03, .04, .05 and .06 [1985], and COMARs 26.13.03.01, .03, .04,
.05, .06 and .08) and transporters of hazardous waste (COMARs
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10.51.04.01, .02, .03 and .04 [1985], and COMARs 26.13.04.01,
.02, .03 and .04). The federal land disposal restrictions
contained in 40 C.F.R. Part 268 would also apply to any off-site
disposal of residual wastes found to exhibit a characteristic of
a hazardous waste.
Alternatives 4, 5 and 6 each entail on-site discharge of treated
ground water to the stream that crosses the southern end of the
Site. Although the stream is not currently used as a public
water supply, its potential for use as a public water supply is
protected under State regulations. State environmental
regulations also require the protection of aquatic life in the
stream. Therefore, the discharge of treated ground water in each
of these alternatives would result in in-stream compliance with
the MCLs and non-zero MCLGs listed above, State water quality
standards (COMARs 26.08.02.03-.03-3), and federal ambient water
quality criteria established pursuant to Section 304 of the Clean
Water Act, 33 U.S.C. § 1314, which apply to the protection of
aquatic life.
In accordance with CERCLA § 121(e), no federal, state or local
permit is required for the portion of any remedial action
conducted entirely on-site. However, Alternatives 4, 5 and 6
would comply with the substantive portions of State and Clean
Water Act requirements pertaining to point source discharges to
surface water (Section 402 of the Clean Water Act, 33 U.S.C.
§ 1342), including discharge limitations (COMARs 26.08.03.01 and
.07), standards for best management practices (40 C.F.R. Part
125, Subpart K) and test procedures (40 C.F.R. Part 136).
Alternatives 5 and 6 require the excavation and placement of
waste material from the PVC sludge disposal cells and would
comply with federal and State hazardous waste identification
requirements (40 C.F.R. § 261.24, COMARs 10.51.02.10, .11 and .12
[1985], and COMARs 26.13.02.11, .12 and .13). Alternative 5
provides for on-site treatment of the wastes by low temperature
thermal desorption. Alternative 6 provides for off-site disposal
of the wastes. On-site handling of any Cell B/C or Cell A wastes
or treated residuals found to exhibit any characteristic of a
hazardous waste would comply with standards applicable to
generators of hazardous waste (COMARs 10.51.03.01, .03, .04, .05
and .06 [1985], and COMARs 26.13.03.01, .03, .04, .05, .06 and
.08) and transporters of hazardous waste (COMARs 10.51.04.01,
.02, .03 and .04 [1985], and COMARs 26.13.04.01, .02, .03 and
.04). The federal land disposal restrictions contained in 40
C.F.R. Part 268 would also apply to any off-site disposal of Cell
B/C or Cell A wastes or treated residuals found to exhibit a
characteristic of a hazardous waste.
Any on-site storage of hazardous wastes in Alternatives 5 and 6
would comply with COMAR 10.51.05.09 (1985) and COMAR 26.13.05.09,
which regulate containers, COMAR 10.51.05.10 (1985) and COMAR
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26.13.05.10, which regulate tanks, COMAR 10.51.05.11 (1985) and
COMAR 26.13.05.11, which regulate surface impoundments, COMAR
10.51.05.12 (1985) and COMAR 26.13.05.12, which regulate waste
piles, and COMAR 10.51.05.07 (1985) and COMAR 26.13.05.07, which
regulate the closure and post-closure care of the storage units.
The alternatives would comply with the substantive requirements
of 40 C.F.R. Part 264, Subpart F, for detecting, characterizing
and responding to releases from solid waste management units.
On-site treatment of Cell B/C wastes in Alternative 5 would
comply with federal standards for air emissions from process
vents (40 C.F.R. Part 264, Subpart AA) and the requirements for
thermal treatment of hazardous waste (40 C.F.R. Part 264,
Subpart X, and 40 C.F.R. Part 265, Subpart P) .
Alternatives 4, 5 and 6 each call for construction of a landfill
cap and post-closure monitoring and maintenance in compliance
with appropriate State landfill closure regulations (COMARs
26.04.07.21 A, B, D and E and COMAR 26.04.07.22 A, B and C) .
COMAR 26.04.07.21 E establishes minimum design requirements for
municipal landfill closure caps which have been found, through
modeling, not to be adequate for this Site. Therefore, the
single-barrier cap specifications presented in the EPA Municipal
Landfill Guidance were taken into consideration in developing
alternatives for the FS and would be considered in evaluating the
protectiveness of the cap design. Landfill gas emissions would
be controlled, if determined by EPA, in consultation with MDE, to
be necessary in order to comply with the substantive portions of
State requirements governing air quality (COMARs 26.11.06.02,
.03, .06, .08 and .09, COMAR 26.11.15 and COMAR 26.11.19.02 G) .
Alternatives 4, 5 and 6 would also comply with the substantive
requirements of the following federal and State environmental
laws: State requirements associated with well construction and
abandonment (COMAR 26.04.04), erosion and sediment control
(COMARs 26.09.01.01, .07 B and .08 A), stormwater management
(COMAR 26.09.02) and noise pollution control (COMARs 26.02.03.02
A (2) and B(2) and COMAR 26.02.03.03 A); federal and State
regulations for the protection of wetlands (Executive Order
119900 and COMAR 08.05.04); and federal regulations for the
protection of endangered species (16 U.S.C. S 1531; 50 C.F.R.
Part 402) and historical sites (16 U.S.C. S 469 and 16 U.S.C.
§5 470 gt seg.) .
In summary, Alternatives 4, 5 and 6 would comply with all ARARs
associated with drinking water (MCLs and non-zero MCLGs) , surface
water (State water quality standards, federal water quality
criteria, and federal and State requirements pertaining to point
source discharges) and air (State regulations pertaining to
hazardous air pollutants and air quality and federal air emission
standards for process vents) . Alternatives 4 through 6 would
also comply with State landfill closure and well construction and
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abandonment requirements, and all ARARs pertaining to hazardous
waste management (federal and State hazardous waste
identification requirements, federal land disposal restrictions,
and State requirements pertaining to generators and transporters
of hazardous waste). In addition, Alternatives 4 through 6 would
comply with federal and State regulations pertaining to sensitive
environments and natural and historic resources. Alternatives 5
and 6 would further comply with federal and State requirements
associated with storage of hazardous waste. In addition,
Alternative 5 would comply with federal requirements for thermal
treatment of hazardous waste.
9.3 Long-Term Effectiveness and Permanence
«.
Alternatives 4, 5 and 6 would reduce risks to acceptable levels
for the ground water pathway since the ground water extraction
and treatment system would permanently remove the contaminants of
concern from the aquifer which underlies the Site. Therefore,
Alternatives 4 through 6 satisfy the requirements for long term
effectiveness and permanence with regard to ground water. Ground
water use restrictions affecting properties near the landfill
could be eliminated once the ground water cleanup levels were
achieved for each of these alternatives.
Alternative 4 provides containment of landfill wastes and wastes
in PVC sludge disposal Cells A and B/C through capping. Capping
is a proven technology; a properly-maintained cap would provide
long-term isolation of source materials and risk reduction when
implemented together with a ground water recovery and treatment
system.
Alternative 5 provides for the treatment of PVC sludge disposal
cell wastes by low temperature thermal desorption. This
technology has the potential to provide a permanent reduction in
the concentration of contaminants that are available for
leaching. However, additional pilot-testing of the low
temperature thermal desorption process would be required to
ensure that the technology is compatible with the PVC sludge and
would meet the cleanup level for vinyl chloride without
generating new chemicals in the waste material that may pose
unacceptable levels of risk.
Alternative 6 provides off-site disposal of Cell B/C wastes and
would permanently eliminate one of the sources of ground water
contamination at the Site.
Treatment and off-site disposal of the PVC sludge wastes
(Alternatives 5 and 6) would not provide significant advantages
over capping alone (Alternative 4) with respect to the activities
required to maintain effectiveness of the remedy over time. Each
of these alternatives would require long-term maintenance of the
landfill cap, monitoring networks and deed restrictions.
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9.4
Alternatives 4, 5 and 6 would reduce the toxicity and volume of
contaminated ground water at the Site with equal effectiveness.
Although VOCs in ground water would ultimately be transferred to
the ambient air, controls for reducing the level of air emissions
to the atmosphere would be implemented if they were determined to
be necessary by EPA, in consultation with MDE. In addition, the
precipitation, flocculation/coagulation, and carbon adsorption
components of the ground water treatment process would produce
contaminated sludges and materials which would have to be
disposed of off-site.
Alternatives 4, 5 and 6 would each provide in-place containment
of landfill wastes and consolidation and containment of mercury-
contaminated soils. Alternative 4 provides in-place containment
of Cell B/C wastes and does not reduce the toxicity or volume of
these wastes. However, the cap would decrease the mobility of
contaminants by reducing the amount of water that may infiltrate
the wastes and cause certain constituents to leach into ground
water.
Alternative 5 provides for treatment of Cell B/C wastes using low
temperature thermal desorption. If the low temperature thermal
treatment process can be designed and regulated to provide
removal of VOCs without generation of toxic by-products.
Alternative 5 would provide a long-term reduction in the
toxicity, mobility and mass of contaminants at the Site.
Alternative 6 entails off-site landfill disposal of Cell B/C
waste materials and would not result in any overall reduction of
toxicity or volume of hazardous substances.
9.5 Short-term Effectiveness
Alternatives 4 through 6 would effectively manage risk during the
construction and implementation phases by employing controls
(i.e., ground water monitoring, deed and ground water use
restrictions, and alternate water supply or point-of-entry
treatment) until the time that cleanup .levels are achieved,
thereby preventing exposure to contaminated ground water in
residential wells.
Implementation of each of these alternatives would present a
potential for exposure of workers to site contaminants during cap
construction activities, installation of ground water monitoring
and extraction wells, construction and operation of the ground
water treatment system, and sampling activities. In addition,
workers would be exposed to normal construction hazards.
However, these risks could be reduced by following proper health
and safety practices for well drilling, sampling and
construction.
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Alternatives 4 through 6 also entail emissions of VOCs from the
air stripper to ambient air. However, these emissions may be
effectively controlled with air emission control equipment in
order to prevent unacceptable levels of exposure.
Alternatives 5 and 6 would pose an additional short-term risk to
workers and neighboring populations as a result of the generation
of dust and VOCs during the excavation and transportation of Cell
B/c wastes. There is also the potential for exposure to
hazardous vapors in the event of a malfunction of the thermal
desorption unit. These additional risks can be reduced through
the implementation of an air monitoring program, emission
controls, the continuous monitoring of the thermal treatment
system, and the incorporation of automatic shut-off features.
«.
9.6 Implementability
Construction of the fence, the landfill cap and the ground water
collection and treatment systems would be easily accomplished
using conventional methods and materials for each of Alternatives
4 through 6. The ground water treatment technologies that would
be implemented under Alternatives 4 through 6 have been
successfully demonstrated in full-scale operations for the
contaminants of concern. However, treatability studies would be
necessary before remedy design in order to optimize the treatment
processes and ensure that discharge of treated ground water to
surface water would comply with the substantive requirements of
the National Pollutant Discharge Elimination System program under
Section 402 of the Clean Water Act, 33 U.S.C. S 1342, and would
not result in an in-stream exceedance of MCLs, non-zero MCLGs,
State water quality standards, or federal ambient water quality
criteria for the protection of aquatic life.
Alternatives 5 and 6 would be more difficult to implement than
Alternative 4. Both of these alternatives involve substantial
excavation of waste which would require additional controls in
order to minimize VOC exposure to workers. Low temperature
thermal desorption has been included in Alternative 5 as a
potentially feasible technology for treatment of PVC sludge
wastes. However, pilot-testing would be required to confirm that
a suitable temperature range exists in which the materials can be
satisfactorily treated without creating hazardous PVC
decomposition products. Additional monitoring and controls would
also be required to protect against potential malfunction of the
thermal desorption unit.
Implementation of Alternative 6 would depend upon acceptance of
the PVC sludge wastes by ah off-site disposal facility. Results
of treatability testing conducted during the Feasibility Study
indicate that the Cell B/C waste does not exhibit the toxicity
characteristic of a hazardous waste and that the material may be
accepted by a RCRA Subtitle 0 industrial waste landfill.
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However, in the event that future analyses of excavated wastes
indicate that any portion of the material exhibits any
characteristic of hazardous waste as defined in 40 C.F.R. Part
261, Subpart C, that portion of the material would have to be
treated on-site or transported to an off-site RCRA Subtitle C
(hazardous waste) disposal facility. This situation would result
in delays in implementation and additional costs.
The remaining components of Alternatives 4 through 6 would not
present any major implementation difficulties. Ground water,
stream and landfill gas monitoring would be performed using
widely practiced techniques. Point-of -entry treatment systems
have been shown to be effective in removing the types of
contaminants associated with this Site. Residential well
replacement, if necessary, would be conducted in accordance with
State regulations. Cooperation from property owners would be
necessary for well installation, maintenance and sampling.
Ground water use restrictions are currently in effect in the area
of the Site and mechanisms exist within the State and County
governments for enforcement and modification of ground water use
restrictions as necessary to ensure protection of public health.
Ground water use restrictions would continue to be reviewed and
revised as additional Site data becomes available. Future use of
the landfill property can be effectively controlled through the
use of deed restrictions.
9.7 coat
The present worth of the selected alternative (Alternative 4) is
estimated at $23,826,000. Alternative 4 is less costly than
Alternatives 5 and 6 but provides the same degree of risk
reduction as those alternatives.
9.8 State Acceptance
MDE has not provided a letter to EPA that indicates whether or
not the State concurs with the selected remedy. However, MDE has
expressed concern that: (1) several of the ground water cleanup
levels set forth in the Proposed Plan for the Site are more
stringent than the MCLs established under the Safe Drinking Water
Act, 42 U.S.C. SS 300f et seq. : and (2) the costs for
implementation of the selected . remedy may exceed the cost
estimate presented in the Proposed Plan.
9.9
Local residents expressed no opposition to most of the elements
of the selected remedy. However, several residents have voiced
their dissatisfaction with the ground water use restrictions
which have been in effect at the Site since 1987 and which would
continue to be implemented until the ground water cleanup levels
have been achieved. The PRPs submitted comments regarding the
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landfill cap and the ground water cleanup levels identified in
the Proposed Plan for the Site. Comments received during the
public comment period concerning the Administrative Record and
the various alternatives are summarized in the Responsiveness
Summary which is a part of this ROD.
10.0 SELECTED REMEDY; DESCRIPTION AND PERFORMANCE STANDARDS
Following review and consideration of the information in the
Administrative Record file, the requirements of CERCLA and the
NCP, and public comment, EPA has selected Alternative 4 (Capping,
Ground Water Extraction and Treatment, Monitoring, Institutional
Controls and Fencing) as the remedy for this Site. Alternative 4
meets,the threshold criteria of overall protection of human
health and the environment and compliance with ARARs, and
provides the best balance of long-term effectiveness and
permanence, reduction of toxicity, mobility or volume of
contaminants through treatment, short-term effectiveness,
implementability and cost.
The selected remedy consists of the following major components:
• Excavation and disposal of soils from the former drain
field of the Transfer Station septic system
• Relocation of the current drain field of the Transfer
Station septic system
* Capping of the landfill and identifiable cells of PVC
sludge
• Ground water extraction
• On-site treatment of extracted ground water and discharge
to the on-site stream
• Ground water, stream and landfill gas monitoring
• Provision of an alternate water supply, if necessary
• Deed and ground water use restrictions
• Perimeter fencing
Each component of the remedy and mandatory performance standards
are described below.
A. Excavation and Disposal of Soils from the Former Drain Field
of the Transfer Station Septic System
An estimated 400 cubic yards of mercury-contaminated soils shall
be excavated from the former drain field of the Transfer Station
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septic system. Soil samples shall be collected and analyzed for
mercury prior to excavation in order to determine the exact area
and volume of soils requiring removal. The number and location
of soil samples and the analytical method to be used shall be
determined by EPA, in consultation with MDE. Soils requiring
removal shall be subjected to the Toxicity Characteristic
Leaching Procedure (TCLP) as described in 40 C.F.R Part 261,
Appendix II, prior to excavation in order to determine whether
those soils exhibit the characteristic of toxicity.
Performance standards for the Excavation and Disposal of Soils
from the Former Drain Field:
All soils containing greater than 1 mg/kg of mercury shall
be excavated from the former drain field. Excavated soils
that are found not to exhibit the characteristic of toxicity
as defined in 40 C.F.R. S 261.24 shall be disposed of near
the center of the landfill prior to its closure. Excavated
soils that are found to exhibit the toxicity characteristic
shall be disposed of at a RCRA hazardous waste (Subtitle C)
off-site disposal facility and shall be managed on-site in
compliance with standards applicable to generators of
hazardous waste (COMARs 10.51.03.01, .03, .04, .05 and .06
[1985], and COMARs 26.13.03.01, .03, .04, .05, .06 and .08)
and transporters of hazardous waste (COMARs 10.51.04.01,
.02, .03 and .04 [1985], and COMARs 26.13.04.01, .02, .03
and .04). The federal land disposal restrictions contained
in 40 C.F.R. Part 268 shall also apply to the off-site
disposal of any soils found to exhibit the toxicity
characteristic.
B. Relocation of the current Drain Field of the Transfer station
Septic System
Prior to installation of the cap on the landfill, the septic
system drain field which is currently in use shall be relocated
from the west side of the Transfer Station in order to prevent
the discharge of liquids from the septic system into areas
occupied by buried wastes.
C. capping of th« Landfill and Identifiable Cells of PVC sludge
Predesign studies shall be conducted in order to more clearly
delineate the boundaries of the fill material, including the
boundaries of PVC sludge disposal Cells A and B/C. A cap
consisting of a prepared subbase, gas collection zone, low
permeability layer, drainage layer, cover material, topsoil and
vegetative layer shall be placed over the landfill and identified
cells of PVC sludge. A cap vegetation design and management plan.
that enhances habitat values for migratory birds shall be
developed in consultation with the U.S. Fish and Wildlife
Service. The cap will cover an estimated 31 acres. The
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approximate areal extent of the cap is shown in Figure 4. The
actual areal extent of the cap will be determined by EPA, in
consultation with MDE, during the design phase, based on data
gathered during the RI and predesign studies.
Further studies shall be performed prior to the design of the cap
in order to determine the landfill gas constituents and the
emission rate. Cecil County, Maryland is located in an area
designated as a "severe-15" ozone non-attainment area under the
Clean Air Act. Therefore, if the landfill emits more than 25
tons per year of VOCs, reasonably available control technology
(RACT), as defined in COMAR 26.11.19.02 G, shall be required in
order to control landfill gas. EPA, in consultation with MDE,
will determine during the remedial design phase whether an active
gas collection system is required in order to comply with State
regulations governing air quality or whether a passive gas
collection system will be sufficient to meet those requirements.
An operation and maintenance plan shall be developed for the cap
and submitted to EPA for approval during the remedial design
phase. Inspection and maintenance of the cap shall continue for
an estimated 30 years or such other time period that EPA, in
consultation with MDE, determines to be necessary, based on the
statutory reviews of the remedial action which shall be conducted
no less often than every five years from initiation of the
remedial action, in accordance with the EPA guidance document,
Structure and Components of five-year Reviews (OSWER Directive
9355.7-02, May 23, 1991). Statutory reviews will be conducted as
long as hazardous substances remain on-site and prevent unlimited
use of, and unrestricted exposure at, the site. If determined to
be necessary by EPA, the operation and maintenance plan shall be
revised after construction of the cap has been completed. The
revised operation and maintenance plan shall be submitted to EPA
for approval.
Performance standards for the Cap:
l. The cap shall be designed and constructed to function
with minimum maintenance, to promote drainage and
minimize erosion of the cover and to accommodate
settling so that the cover's integrity is maintained.
2. The cap shall be constructed in compliance with all
location-specific ARARs, including the Archaeological
and Historical Preservation Act of 1974, 16 U.S.C.
§ 469, the National Historic Preservation Act of 1986,
16 U.S.C. §§ 470 et seq.. the Endangered Species Act
(16 U.S.C. S 1531; 50 C.F.R. Part 402) and federal and
State regulations for the protection of wetlands
(Executive Order 119900 and COMAR 08.05.04).
3. The cap shall completely cover the landfill, PVC sludge
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disposal Cell B/C, and Cell A, if Cell A is found during
the predesign studies.
4. The cap shall consist of a prepared subbase, a gas
collection zone, a low permeability layer, a drainage
layer, cover material, topsoil and a vegetative layer in
conformance with the single-barrier cap specifications
presented in the EPA Municipal Landfill Guidance. The
cap shall also meet the landfill closure cap
requirements of COMARs 26.04.07.21 B and E.
5. The low permeability layer of the cap shall consist of
24 inches of clay with a permeability less than or equal
to IX 10~7 centimeters per second (cm/sec), or a
synthetic liner that is equally protective, as
determined by EPA. The choice of materials for the low
permeability layer shall be made by EPA, in consultation
with MDE, during the remedial design.
6. An active gas collection system, utilizing RACT, shall
be installed if EPA, in consultation with MDE,
determines that such a system is necessary in order to
comply with the substantive portions of State
requirements governing air quality (COMARs 26.11.06.02,
.03, .06, .08 and .09; COMAR 26.11.15; and COMAR
26.11.19.02 G). If EPA, in consultation with MDE,
determines that an active gas collection system will not
be necessary in order to comply with these ARARs, a
passive gas collection system shall be installed. The
requirements for the gas collection system will be
determined by EPA, in consultation with MDE, during
remedial design.
D. Ground Water Extraction
Ground water shall be extracted from the aquifer using a
collection system of multiple recovery wells, the exact location
and number of which will be determined by EPA, in consultation
with MDE. At least one round of samples shall be collected from
existing Site monitoring wells during the predesign phase and
analyzed for volatile and semivolatile organic compounds,
pesticides and metals, in order to determine the extent of the
ground water contaminant plume at that time. Aquifer tests shall
be performed during the predesign phase in order to define
aquifer characteristics, if such tests are determined to be
necessary by EPA, in consultation with MDE.
An operation and maintenance plan shall be developed for the
ground water recovery system and submitted to EPA for approval
during the remedial design phase. Operation and maintenance of
the ground water recovery system shall continue for an estimated
30 years or such other time period as EPA, in consultation with
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MDE, determines to be necessary, based on the statutory reviews
of the remedial action which shall be conducted no less often
than every five years from initiation of the remedial action in
accordance with the EPA guidance document, Structure and
Components of Five-Year Reviews (OSWER Directive 9355.7-02, May
23, 1991). Statutory reviews will be conducted as long as
hazardous substances remain on-site and prevent unlimited use and
unrestricted exposure at the Site. The operation and maintenance
plan shall be revised after construction of the collection system
has been completed, if it is determined to be necessary by EPA.
The revised operation and maintenance plan shall be submitted to
EPA for approval.
Performance Standards for Ground Water Extraction:
1. The number and location of recovery wells will be
determined by EPA, in consultation with MDE, during the
remedial design phase and shall be sufficient to control
the migration of contaminants and to achieve the ground
water cleanup levels listed in Tables 9 and 10
throughout the area of attainment. The area of
attainment is defined as the area outside the boundary
of any waste remaining in place up to and including the
boundary of the contaminant plume.
2. Recovery wells shall be installed in accordance with
State regulations governing well construction (COMAR
26.04.04).
3. The extraction of ground water shall reduce the levels
of the contaminants of concern in the area of attainment
to the ground water cleanup levels listed in Tables 9
and 10. The concentrations of contaminants in ground
water beneath the area of any wastes left in place
(waste management area) need not meet the ground water
cleanup levels. However, the extraction of ground water
shall reduce the contaminant concentrations in the
ground water beneath the waste management area so that
subsequent migration of contaminants from this area will
not result in an exceedance of ground water cleanup
levels within the area of attainment. The points at
which compliance with the cleanup levels will be
measured (points of compliance) shall include all well
locations included in the monitoring program discussed
below.
If sampling confirms that cleanup levels have been
achieved throughout the area of attainment at the points
of compliance, and that the concentrations of the
contaminants of concern remain at or below cleanup
levels for 12 consecutive quarters, operation of the
collection system can be suspended. If, subsequent to
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the collection system shutdown, semi-annual monitoring
shows that the concentrations of contaminants of concern
within the area of attainment exceed the cleanup levels,
the collection system shall be restarted and ground
water extraction shall continue until the cleanup levels
have once more been attained for twelve consecutive
quarters. Semi-annual monitoring shall continue until
EPA, in consultation with MDE, determines that the
contaminant concentrations have stabilized at or below
the cleanup levels.
E. on-site Treatment of Extracted Ground Water and Discharge to
the On-site stream
•.
Extracted ground water shall be treated on-site in a three-step
process. The first step shall entail precipitation and
flocculation/coagulation to remove manganese and other inorganic
contaminants. In the second step, the filtered effluent from the
precipitation unit shall be piped to an air stripper column for
removal of VOCs. Finally, the ground water discharged from the
air stripper shall be passed through granular activated carbon to
remove semivolatile organic compounds and any remaining
contaminants. The treated ground water shall then be discharged
to the stream that crosses the southern end of the Site.
Predesign studies shall be performed in order to determine the
conditions and procedures required to meet the performance
standards and comply with the ARARs set forth below.
Air emission and dispersion modeling and a human health risk
assessment shall be conducted during the predesign phase in order
to evaluate the risks associated with exposure to emissions from
the air stripper. The risk assessment shall be submitted to EPA
for approval. EPA, in consultation with MDE, will determine the
actual treatment conditions and emission control requirements for
the air stripper based on the results of the predesign studies
and the risk assessment.
The management and ultimate disposition of treatment residuals
shall be determined during the predesign phase and is subject to
EPA approval. Such management shall entail treatment and/or
disposal.
An operation and maintenance plan shall be developed for the
ground water treatment system and submitted to EPA for approval
during the remedial design phase. Operation and maintenance of
the ground water treatment system shall continue for an estimated
30 years or such other time period as EPA, in consultation with
MDE, determines to be necessary, based on the statutory reviews
of the remedial action which shall be conducted no less often
than every five years from initiation of the remedial action in
accordance with the EPA guidance document, Structure and
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Components of Five-Year Reviews (OSWER Directive 9355.7-02, May
23, 1991). Statutory reviews will be conducted as long as
hazardous substances remain on-site and prevent unlimited use and
unrestricted exposure at the Site. The operation and maintenance
plan shall be revised after construction of the treatment system
has been completed, if is determined to be necessary by EPA. The
revised operation and maintenance plan shall be submitted to EPA
for approval.
The performance of the ground water recovery and treatment
systems shall be carefully monitored on a regular basis. If EPA,
in consultation with MDE, determines that alteration of the
system is appropriate, based on performance data collected during
operation, the system shall be modified. These modifications nay
include any or all of the following:
l. discontinuation of pumping at individual wells where
cleanup levels have been attained;
2. alternating pumping at wells to eliminate stagnation
points;
3. pulse pumping to allow adsorbed contaminants to
partition into ground water and facilitate aquifer
equilibration; and
4. installation of additional recovery wells to facilitate
or accelerate cleanup of the contamination.
The Performance standards for the en-site Treatment of Extracted
Ground Water and Discharge to the On-Site Stream:
1. The collection, treatment and discharge facilities shall
be constructed and sited in compliance with the
requirements in the Archaeological and Historical
Preservation Act of 1974, 16 U.S.C. S 469, the National
Historic Preservation Act of 1986, 16 U.S.C. SS 470 et
seg.f the Endangered Species Act (16 U.S.C. S 1531;
50 C.F.R. Part 402) and federal and State regulations
for the protection of wetlands (Executive Order 119900
and COMAR 08.05.04).
2. The on-site treatment system shall reduce contaminant
levels in the extracted ground water to concentrations
that EPA, in consultation with MDE, has determined: (1)
shall achieve compliance with State water quality
standards (COMARs 26.08.02.03-.03-3) and federal ambient
water quality criteria established for the protection of
aquatic life pursuant to Section 304 of the Clean Water
Act (33 U.S.C. § 1314); and (2) shall not result in an
exceedance of MCLs (40 C.F.R. §§ 141.11-.12 and 141.61-
.62) and non-zero MCLGs (40 C.F.R. SS 141.50-.51) in the
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receiving body of water.
3. Emissions from the air stripper shall not result in an
excess lifetime cancer risk greater than l X 10~6 for
exposed individuals. Air emission controls shall be
installed if EPA, in consultation with MDE, determines
that emissions from the air stripper stack could result
in such excess lifetime cancer risk. Air stripper
emissions shall also meet the substantive requirements
of State regulations pertaining to toxic air pollutants
(COHAR 26.11.15), federal air emission standards for
process vents (40 C.F.R. Part 264, Subpart AA), and
State regulations pertaining to emissions of VOCs (COMAR
26.11.06.06). The EPA guidance document, Control of Air
Emissions from Superfund Air Strippers at Superfund
Groundvater Sites (OSWER Directive 9355.0-28, June 15,
1989), shall also be considered in determining the need
for air emission controls.
4. Residual wastes shall be evaluated in accordance with
the hazardous waste identification requirements of 40
C.F.R. § 261.24, COMARs 10.51.02.10, .11 and .12 (1985),
and COMARs 26.13.02.11, .12 and .13. On-site handling
of any residual wastes found to exhibit a characteristic
of a hazardous waste shall comply with standards
applicable to generators of hazardous waste (COMARs
10.51.03.01, .03, .04, .05 and .06 [1985], and COMARs
26.13.03.01, .03, .04, .05, .06 and .08) and
transporters of hazardous waste (COMARs 10.51.04.01,
.02, .03 and .04 [1985], and COMARs 26.13.04.01, .02,
.03 and .04). The federal land disposal restrictions
contained in 40 C.F.R. Part 268 shall also apply to any
off-site disposal of residual wastes found to exhibit a
characteristic of a hazardous waste.
5. Discharge of treated ground water to the on-site stream
shall comply with the substantive requirements of State
and federal regulations pertaining to point source
discharges to surface water, including discharge
limitations (COMARs 26.08.03.01 and .07), standards for
best management practices (40 C.F.R. Part 125,
Subpart K) and test procedures (40 C.F.R. Part 136).
F. Ground water Monitoring
A ground water monitoring program shall be implemented during the
remediation phase in order to evaluate the effectiveness of the
ground water collection and treatment system in meeting cleanup
levels and to ensure protection of nearby residents. EPA, in
consultation with MDE, will determine the number and location of
new monitoring wells and the exact location of the existing
monitoring wells and residential wells to be included in the
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ground water monitoring network during the remedial design phase.
The frequency and duration of sampling and the analytical
parameters and methods to be used will be determined by EPA, in
consultation with MDE, during the remedial design phase.
Annual monitoring of select residential wells (interim
monitoring) began in May 1993 and shall continue until the post-
construction ground water monitoring program begins. If
determined to be necessary by EPA, in consultation with MDE, the
number and location of residential wells in the interim
monitoring program, the frequency of monitoring, and/or the
analytical parameters and methods to be used for interim
monitoring activities shall be modified.
An operation and maintenance plan for implementation of the
ground water monitoring program and maintenance of the ground
water monitoring network shall be prepared and submitted to EPA
for approval during the remedial design phase. Monitoring and
maintenance shall continue for an estimated 30 years or such
other time period as EPA, in consultation with MDE, determines to
be necessary based on the statutory reviews of the remedial
action which shall be conducted no less often than every five
years from initiation of the remedial action in accordance with
the EPA guidance document, Structure and Components of Five-year
Reviews (OSWER Directive 9355.7-02, May 23, 1991). Statutory
reviews will be conducted as long as hazardous substances remain
on-site and prevent unlimited use and unrestricted exposure at
the Site.
Performance Standards for Nev Monitoring Wells:
New monitoring wells shall be installed in accordance with
State requirements for well construction (COMAR 26.04.04).
6. Stream and wetland Monitoring
An unnamed creek, which is a tributary of Basin Run, flows across
the southern end of the Site. A post-construction stream and
wetland monitoring program shall be implemented in order to: (1)
evaluate Site impacts on the unnamed creek and potential Site
impacts on a forested wetland area located along the creek
approximately one mile downstream from Waibel Road; (2) identify
any changes in conditions in the stream or forested wetland due
to implementation of the selected remedy; and (3) assess the need
for additional stream and wetland studies or additional remedial
action.
Surface water and sediment samples shall be collected from
upstream and downstream locations in the unnamed creek and from
the palustrine forested wetland that is located along the unnamed
creek, approximately one mile downstream from Waibel Road. The
exact number and location of samples will be determined by EPA,
58
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in consultation with MDE, during the remedial design phase.
These samples shall be analyzed for volatile and semivolatile
organic compounds, pesticides and metals. In addition, surface
water parameters such as temperature, dissolved oxygen, pH,
conductivity and flow rate shall be measured at each sampling
station. Surface water samples from each station shall also be
analyzed for total suspended solids, alkalinity and hardness.
Similarly, the temperature, oxidation-reduction potential (Eh),
pH, conductivity and color (as determined by comparison with the
Munsell Soil Color Charts) of sediments at each sample location
shall be measured. Sediment samples from each sampling location
shall also be analyzed for total organic carbon, grain size,
percent moisture and percent solids. Biological monitoring of
aquatic macroinvertebrates, in accordance with EPA's guidance
document, Rapid Bioassessment Protocol for Use in Streams and
Rivers: Benthic Macroinvertebrates and Fish (EPA/444/4-89-001,
May 1989), shall be conducted twice a year for the first year of
post-construction monitoring and once a year thereafter.
EPA, in consultation with MDE, will determine the need for
additional stream studies or further remedial action to address
the quality of water in the unnamed creek based on the stream
monitoring data and the following conditions and criteria:
upgradient stream conditions, State water quality standards and
federal ambient water quality criteria. EPA, in consultation
with MDE, will determine the need for additional stream and
wetland studies or further remedial action to address the quality
of the sediments in the unnamed creek or the downstream wetland
based on the stream and wetland monitoring data and the following
conditions and criteria: upgradient stream conditions, Apparent
Effects Thresholds (AETs) and NOAA Biological Effects Range - Low
(ER-L).
In order to establish a baseline for the long-term stream
monitoring program, before construction of the selected remedy
begins, at least one round of samples shall be collected from
upstream and downstream locations in the unnamed creek, including
a station in the forested wetland that is located about one mile
downstream of Waibel Road. These samples shall be analyzed for
the chemical and physical parameters specified above. In
addition, a macroinvertebrate survey shall be performed for
upstream and downstream locations in the unnamed creek and the
forested wetland, in accordance with the methods prescribed
above. The stream sampling and macroinvertebrate survey shall be
conducted in the late spring or early autumn. EPA, in
consultation with MDE, will determine the specific number and
location of pre-construction monitoring points during the
remedial design phase.
H. Landfill Gas Monitoring
A network of soil-gas monitoring probes shall be installed around
the perimeter of.the landfill in order to evaluate the potential
59
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for off-site migration of landfill gas and to assess the need for
further remedial action to prevent the migration of landfill gas
toward residences near the Site. The number and location of
soil-gas probes shall be determined by EPA, in consultation with
MDE, during the remedial design phase. Samples shall be
collected from the gas monitoring probes on a quarterly basis
until EPA, in consultation with MDE, determines that the
frequency of the monitoring should be changed or that landfill
gas monitoring is no longer necessary. The soil-gas samples
shall be analyzed for VOCs and methane. Additional remedial
action shall be required to control off-site migration of
landfill gas if EPA, in consultation with MDE, determines that it
is necessary in order to protect human health, welfare, or the
environment, or to comply with COMAR 26.04.07.21(5)(b), which
specifies that the concentration of methane at the landfill
property boundary may not exceed the lower explosive limit for
methane in air, or 5.40 percent by volume.
I. Provision of an Alternate Water Supply, if Necessary
If EPA, in consultation with MDE, determines that any residential
well is contaminated with Site-related contaminants at
concentrations that exceed the ground water cleanup levels, an
alternate water supply shall be provided at that residence. The
alternate water supply shall consist of either wellhead treatment
at the point of entry or installation of a new well in an
uncontaminated area of the aquifer. The choice of alternate
water supply will be made by EPA, in consultation with MDE.
Wellhead treatment may include physical and/or chemical
processes. The choice of the wellhead treatment unit or process
will be made by EPA, in consultation with MDE, and will be based
on the type and concentration of contaminant(s) detected.
Wellhead treatment units shall be maintained according to
manufacturer's specifications so that the contaminant
concentrations in the water exiting the treatment system remain
at or below ground water cleanup levels. An operation and
maintenance plan for the wellhead treatment systems shall be
submitted to EPA for approval.
The wellhead treatment systems may result in the production of
residual treatment wastes. These wastes (e.g., spent carbon
adsorption units or filtration media) shall be evaluated in
accordance with the hazardous waste identification requirements
of 40 C.F.R. § 261.24, COMARs 10.51.02.10, .11 and .12 (1985),
and COMARs 26.13.02.11, .12 and .13. On-site handling of any
residual wastes found to exhibit a characteristic of a hazardous
waste shall comply with standards applicable to generators of
hazardous waste (COMARs 10.51.03.01, .03, .04, .05 and .06
[1985], and COMARs 26.13.03.01, .03, .04, .05, .06 and .08) and
transporters of hazardous waste (COMARs 10.51.04.01, .02, .03 and
.04 [1985], and COMARs 26.13.04.01, .02, .03 and .04). The
federal land disposal restrictions contained in 40 C.F.R. Part
60
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268 shall also apply to any off-site disposal of residual wastes
found to exhibit a characteristic of a hazardous waste.
Performance Standard for Alternate Water Supply:
1. A wellhead treatment system shall.reduce the
concentrations of the contaminants of concern in the
residential well water to the ground water cleanup
levels in Tables 9 and 10.
2. A replacement well shall be installed in an
uncontaminated portion of the aquifer in order to
provide a sufficient quantity of water which meets the
ground water cleanup levels identified in Tables 9 and
10. Replacement wells shall be installed in accordance
with State requirements for well construction (COMAR
26.04.04).
J. Deed Restriction
As soon as practicable, restrictions shall be placed on the deed
to the Site (parcel 267) in order to prevent installation of
drinking water wells on the property and any future uses of the
property that could compromise the effectiveness of the selected
remedy. The deed restrictions shall remain in effect until EPA,
in consultation with MDE, determines that they are no longer
required to protect human health and welfare and the environment.
K. Ground Water Use Restriction
MDE and the County currently restrict the use of ground water in
the area of the Site through restrictions on the installation of
new water supply wells. These restrictions on the installation
of new water supply wells will continue to be reviewed and
revised as additional Site data becomes available and will remain
in effect until the ground water cleanup levels have been
achieved throughout the area of attainment. Mechanisms exist
within MDE and the Cecil County Health Department for the
enforcement and modification of the ground water use
restrictions.
Performance Standard for Ground water use Restrictions
The ground water use restriction zone shall encompass the
landfill property (parcel 267), the area of attainment as
defined in paragraph 10.D.I, above, and an appropriate buffer
zone. The objectives of these restrictions is to limit the
potential for exposure to contaminated ground water and to
minimize the extent to which the contaminant plume could be
extended as a result of additional ground water use.
61
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L. Perimeter Fencing
A chain-link fence shall be constructed around the perimeter of
the landfill property, excluding the Transfer Station building
and rear loading area, in order to prevent unauthorized access to
the Site. Plans for maintenance of the fence shall be submitted
to EPA for approval during the remedial design phase.
Performance standard for Perimeter Fencing
1. The chain-link fence shall have a minimum height of six
feet and shall be equipped with locking gates.
2; The fence shall be maintained in a manner sufficient to
prevent unauthorized access to the landfill until such
time as EPA, in consultation with MDE, determines that
access restrictions are no longer required.
M. Ecological Actions
The Site is located within the known range of the bog turtle
(Clemmys muhlenbercril, which is a candidate for federal listing
as a threatened species. A predesign investigation shall be
conducted by a qualified herpetoiogist in order to determine
whether or not bog turtles occur on the Site and, if they are
present, ways to avoid or minimize disturbance of the turtles
during remedial action. In addition, a habitat impact analysis
which evaluates the potential impact of remedial activities on
migratory bird and anadromous fish habitats shall be prepared
during the predesign phase, in consultation with the U.S. Fish
and Wildlife Service, and submitted to EPA for approval. If
determined to be necessary by EPA, in consultation with MDE,
detailed habitat restoration and replacement plans shall be
developed for EPA approval during the remedial design phase and
implemented in order to rectify any unavoidable adverse effects
of remedial activities on the U.S. Department of the Interior
trust resource habitats.
11.0 GROUND WATER REMEDY IMPLEMENTATION
This remedial action shall restore ground water to its beneficial
use, which at this Site includes its use as a drinking water
source. It may become apparent during implementation or
operation of the remedy that contaminant levels have ceased to
decline and are remaining constant at levels higher than the
ground water cleanup levels over some portion of the area of
attainment. If EPA, in consultation with MDE, determines that
implementation of the selected remedy demonstrates, with
corroborating hydrogeologic and chemical evidence, that it will
be technically impracticable to achieve and maintain the cleanup
levels throughout the entire area of ground water contamination,
EPA may require that any or all of the following measures be
62
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taken, for an indefinite period of time, as further modifications
of the in-place system:
1. long-term gradient control may be provided by low level
pumping, as a containment measure;
2. cleanup levels may be modified and chemical-specific
ARARs may be waived for those portions of the aquifer
for which EPA, in consultation with MDE, determines that
it is technically impracticable to achieve further
contaminant reduction;
3. institutional controls may be modified or maintained to
restrict access to those portions of the aquifer where
contaminants remain above cleanup levels; and
4. remedial technologies for ground water restoration may
be reevaluated.
The decision to invoke any or all of these measures may be made
by EPA, in consultation with MDE. If necessary, EPA will issue
an Explanation of Significant Differences or a ROD amendment.
12 . 0 STATUTORY DETERMINATIONS
EPA's primary responsibility at Super fund sites is to undertake
remedial actions that are protective of human health and the
environment. In addition, Section 121 of CERCLA, 42 U.S.C.
§ 9621, establishes several other statutory requirements and
preferences. These requirements specify that when complete, the
selected remedial action for each site must comply with
applicable or relevant and appropriate environmental standards
established under federal and state environmental laws (ARARs)
unless a statutory waiver is invoked. The selected remedy also
must be cost effective and utilize treatment technologies or
resource recovery technologies to the maximum extent practicable.
Finally, the statute includes a preference for remedies that
permanently and significantly reduce the volume, toxicity or
mobility of hazardous substances. The following sections discuss
how the selected remedy for this Site meets these statutory
requirements .
12 • 1 Protection of Hmmiit Health and the
The selected remedy protects human health and the environment by
controlling exposure to contaminated ground water, soils and seep
sediments and by reducing contaminant loading to ground water and
local surface water.
Capping and ground water collection and treatment will prevent
further migration of contamination from the Site and effectively
reduce contaminant levels in the aquifer. Consequently, these
63
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measures will reduce the potential for exposure to contaminated
ground water and the potential for Site contaminants to enter the
unnamed creek. Ground water monitoring will provide data for
evaluating the effectiveness of the remedial action and will
ensure that any unacceptable levels of contaminants in
residential wells will be detected and addressed prior to and
during the remediation phase. If necessary, wellhead treatment
will reduce contaminant levels to acceptable ground water cleanup
levels or well replacement will provide water from an
uncontaminated portion of the aquifer, thereby reducing or
eliminating exposure. Ground water use restrictions will prevent
future exposure to contaminated ground water by limiting the
future installation of wells in the contaminated aquifer until
ground.'water cleanup levels have been achieved. Once the cleanup
levels have been achieved, the carcinogenic risk associated with
exposure to ground water shall be within EPA's target risk range
of l X 10'6 to 1 X 10"4 and there will be no significant
potential for adverse noncarcinogenic health effects as a result
of exposure to ground water (i.e, the hazard index shall be less
than or equal to one).
Stream monitoring and landfill gas monitoring will provide a
basis for additional remedial action, if it is determined to be
necessary by EPA, in consultation with MDE, in order to mitigate
Site impacts on the stream and prevent off-site migration of
landfill gas. Deed restrictions will prohibit on-site activities
that could compromise the effectiveness of the remedy or result
in unacceptable levels of exposure to Site contaminants.
Air emissions from the air stripping unit will be reduced to
acceptable risk-based levels by the installation of emission
controls, if they are determined to be necessary by EPA, in
consultation with MDE. Treated ground water which is discharged
to the unnamed creek will meet all appropriate water quality
standards in order to prevent any adverse environmental effects.
Through monitoring, institutional controls and treatment, this
remedy will be protective of human health and the environment
during and upon completion of the remedial action.
12.2 Compliance vith Applicable or Relevant and Appropriate
Requirements
The selected remedy shall attain all action-, location- and
chemical-specific applicable or relevant and appropriate
requirements for the Site which are listed in Table 11. Also
included in the table are criteria, advisories or guidance "to be
considered11 (TBCs) for implementation of this remedy.
12.3 Cost-Effectiveness
The selected remedy, Alternative 4, is cost-effective in that it
mitigates the risks posed by the contaminants associated with the
64
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Site, meets all other requirements of CERCLA, and affords overall
effectiveness proportionate to the cost. The estimated present
worth cost for the selected remedy is $23,826,000. The costs
associated with the alternatives that did not include ground
water extraction and treatment, Alternatives 2 and 3, are
comparatively lower ($4,436,000 and $15,856,000, respectively)
than the costs of the selected remedy, but those alternatives
would not achieve all of the remedial action objectives. The
costs associated with Alternatives 5 arid 6 are comparatively
higher ($30,902,000 and $37,135,000, respectively).
12.4 Utilization of Permanent Solutions and Alternative
Treatment Technologies to the Max^""11" Extent Practicable
The selected remedy for the Site utilizes permanent solutions and
treatment technologies to the maximum extent practicable.
Although Alternative 5 includes low temperature thermal
desorption of the volatile constituents of Cell B/C wastes and
would provide some additional level of treatment, it provides no
additional risk reduction as compared with the selected remedy
since both of these alternatives would attain the same ground
water cleanup levels and prevent exposure to contaminated soils
and sediments. In addition, Alternative 5 is more costly and
would require the same level of maintenance activities as the
selected remedy, as well as institutional controls.
12.5 Preference for Treatment as a Principal Element
The selected remedy uses treatment as a principal element to
address the threats posed by contaminants in the ground water at
the Site. Wastes buried at the site and contaminated soils pose
a relatively low long-term threat and shall be managed with a
combination of engineering and institutional controls.
13.0 DOCUMENTATION OF SIGNIFICANT CHANGES
The following changes have been made since the Proposed Plan was
issued on May 26, 1993:
1. The Proposed Plan presented specific and unique ground water
cleanup levels for each of 20 contaminants. Based on
comments received during the public comment period, EPA has
modified the cleanup levels for six of the ground water
contaminants. The final ground water cleanup levels take
into account background concentrations of arsenic and
manganese and provide flexibility in meeting the ground
water cleanup levels for those chemicals that may result in
noncarcinogenic adverse health effects in exposed
populations .
2. At least one monitoring station shall be sited in the
palustrine forested wetland that is located along the
65
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unnamed creek approximately one mile downstream of Waibel
Road.
3. A predesign study shall be conducted in order to determine
if the bog turtle (Clemmvs muhlenberail occurs at the Site.
If the turtle is found to occur at the Site, remedial
activities shall be conducted in such a way as to avoid or
minimize disturbance of the turtle.
4. A habitat impact analysis which evaluates the potential
impact of remedial activities on migratory bird and
anadromous fish habitats shall be prepared during the
predesign phase. Detailed habitat restoration and
replacement plans shall be developed and implemented, if
they are determined to be necessary by EPA.
66
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List of References
Foster, S.A. and P.C. Chrostowski, 1986, "Integrated Household
Exposure Model for Use of Tap Water Contaminated with Volatile
Organic Chemicals,11 presented at the 79th Annual Meeting of the
Air Pollution Control Association, Minneapolis, Minnesota, June
22-27, 1986.
Hannah, S.R., G.A. Briggs, and R.P. Hosku, Jr., 1982, Handbook on
Atmospheric Diffusion, Atmospheric Turbulence and Diffusion
Laboratory, NOAA.
Summers, K.S-, S. Cherini and C. Chen, Tetra Tech, Inc., 1980,
"Methodology to Report the Potential for Groundwater
Contamination from Geothermal Fluid Releases,11 EPA/600/7-80/117.
Turner, O.B., 1970, Workbook of Atmospheric Dispersion Estimates,
Air Resources Field Research Office, Environmental Science
Services Administration, U.S. EPA Office of Air Programs,
Research Triangle Park, North Carolina.
U.S. EPA, 1984, Rapid Assessment of Exposure to Particulate
Emissions for Surface Contaminant Sites, Office of Health and
Environmental Assessment, U.S. Environmental Protection Agency,
Contract No. 68-03-3116.
-------
DVT OF ASSESSMENTS * TAXATION MAP DIVISION
OUAMANCU M9NC SUN M. PHOTO 2BO-JO
MAP MOS If * 2i OATU) 1 I 88. SCA1C r-»OO'
IFCfMO-
CIB '
ITZ-I
DOMESTIC BOMOCK WU.
BEDROCK HEU MSTA1UD BY
IT CORPORATION
SOL PCZOMETER MSTAUEO BY
IT CORPORATION
I. PADCtL NUUBCRS («.g PXM) M BOU) f ACE
ARE CROSS-«fWHC€0 TO CUMCNT
HOMt 0*NH) NAMES M TABU • OF
o.
2. MOMTOHMO
-------
LECfMP-
-
WEU. NAME AND LOCATION
GROUNDWATER ELEVATION
(MEASURED 2/26-28/91)
CROUNDWATER CONTOURS (FEET USL)
INFERRED WHERE OA9CD
ANOMALOUS DATA POMT
CROUNOWATER UOOCL BOUNDARY
CONDITION
U.S.C.S. 7.S MNUTC TOPOGRAPHY HAP
RISMC SUM OUAORAMGLC. MAKVLANO-POMSYLVAMA
PHOTORCMSED 1985. SCAU: r-2000*
SCALE
2000 fill
MQTEi
t. PARCEL NUMUS («.«. PXI9) ARC
CROSS-REFERENCED TO CURRENT
HOMCOWEK NAMES M TAKŁ 6.
FIGURE I
ONOUNOWA1ER ELEVATKMS
REOONAL AOUVCM
PREPARED FOR
WOOOUkWN
PHASE W
2. MUNOART CONOTION IS
NO-fUMrr NOT SPEOFKDi
-------
-------
PROPOSED LOCATION If
OF QROUNOWATER
•mEATMEHT SYSTEM-7 H
I I i
APPROX. LOCAT*
LOCATION- /•Ł!
)«»irT^S I i
•* /-'•\
x4salJt
./X^ ~-~^A» MMf
-------
Table 1
Dftected 'm Site Ground Water Wells'
Woodlawn Landfill, Cecil County, Ma^and
(Page 1 of 4)
Constituent
Voiataes G*g/U
Acetone
Benzene
2-Butanone
Chlorobenzene
Chloroethane
1,1-Dichloroethane
1 ,2-Oichloroethane
1 ,2-Dichloroethene
Ethylbenzene
Methylene chloride
Tetrachloroethene
Toluene
Trichloroethene
Vinyl chloride
Xylenes (total)
SenwoJaffles G*g/L)
Benzoic acid
Oiethylphthalate
Dkvbutylphthalate
Bis(2-ethylhexyl)phthalate
Di-n-octylphthalate
Pentachiorophenol
Range of
Concentrations"
ND1 0-600
ND5-4
N010-63
ND5-23
ND10-3
ND5-7
ND5-410
ND5-3
ND5-4
ND5-38
N05-8
ND5-12
ND5-60
ND0.1 8-520
ND5-13
ND50-100
ND10-24
ND10-4
ND10-140
ND10-2
ND50-7
Frequency of
Occurrence
4/15
9/15
3/15
4/15
3/15
4/15
1/15
1/15
3/15
5/15
2/15
5/15
3/15
14/18
5/15
6/48
11/48
22/48
19/48
1/48
1/48
95% Upper
Bound
Cor tcenti ation
115
2.56
15.8
8.93
4.93d
3.17
77.5
2.59
2.91
10.4
3.44
5.00
13.1
126
5.53
29.4
6.70
4.1 4d
18.1
5.04d
25.2"
See footnotes at end of table.
-------
Table 1
(Page 2 of 4)
Constituent
Ruoranthene
Pyrene
Butylbenzytphthalate
Benzo(a)anthracene
Chrysene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Benzo(a)pyrene
1 ,3-Dichlorobenzene
1 ,4-DichJorobenzene
Naphthalene
Dimethytphtnalate
Phenanthrene
1 ,2-Dtehlorobenzene
2-Methylnaphthalene
Acenaphthene
Dibenzofuran
Fluorene
Anthracene
Carbazote
Pesticides (pg/L)
Alpha-BHC
Endosutfanl
Heptachlor
Gamma BHC (IJndane)
Gamma Chlordane
Range of
Concentrations6
ND10-3
ND10-5
ND10-2
ND10-6
ND10-5
ND10-5
ND10-6
ND10-5
ND10-4
N010-4
ND10-2
N010-1
ND10-10
ND10-7
ND10-3
ND10-19
N010-15
ND10-25
ND10-4
19
ND0.05O.19
NDO.05-1.7
NDO.05-0.082
NDO.05-0.02
NDO.5-0.028
Frequency of
Occurrence
2/48
4/48
1/48
5/48
5/48
4/48
2/48
2/48
1/48
7/48
1/48
1/48
1/48
1/39
1/39
1/39
1/39
1/39
1/39
1/1
7/39
3/39
2/39
1/39
1/39
95% Upper
Bound
Concentration*
5.02-
4.99
5.04d
5.02
4.99
5.01 d
5.05
5.00
5.01 d
4.87^
5.04d
5.05d
527
5.13
5.03d
5.96
5.68
6.37
5.01d
19-
0.044
0.15
0.029
0.025d
025?
See footnotes at end of table.
-------
Table 1
(Page 3 of 4)
Constituent
AJdrin
Endrin Ketone
Mstais (mg/L)
Aluminum
Arsenic
Barium
Cadmium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Silver
Vanadium
Zinc
Range of Frequency of
Concentrations'* Occurrence
NDO.05-0.18
NDO. 1-0.024
NDO.2-1.84
ND0.01 -0.008
NDO.1-0.214
NOO.005-0.119
NDO.01-0.0169
NDO.05-0.0512
NDO.025-0.0043
NDO.05-43.5
NDO.003-0.278
0.929-34.8
0.112-24.2
ND0.0002-
0.0026
NDO.04-0.0152
ND0.01 -0.0097
NDO.05-0.0202
NDO.02-0.0994
1/39
1/39
10/15
3/15
14/15
5/15
7/15
9/15
3/15
14/15
3/15
15/15
15/15
4/15
7/15
5/15
8/15
10/15
95% Upper
Bound
Concentration6
0.035
0.050d
0.414
0.0056
0.104
0.024
0.010
0.030
0.012"
17.0
0.053
15.7
8.76
0.00091
0.01 79d
0.00602
0.0203d
0.0396
*On-sfte ground water monitoring wells used for purposes of the Risk Assessment
include fTB-1, ITB-2, fTB-3, ITB-5, ITS-1, F-2, F-3, F-5 through F-10, B-2 through B-4,
OW-1, OW-2, SW-1, and TSW-1 for semivolatile and pesticide compounds; and ITB-5,
F-2, F-3, F-5 through F-7, SW-1 and TSW-1 for volatile and metal constituents.
bND = Not detected at concentration shown. In some instances, constituents were
detected at trace concentrations below the detection limit. As a result, some of the
maximum range values are below the detection limit
°The concentration of the 95 percentile upper bound of the mean calculated using
one-half of nondetect values. In instances where the upper bound value was greater
-------
Table 1
(Page 4 of 4)
than the maximum concentration, the maximum concentration was used in the Risk
Assessment
"Maximum observed concentration was used in the Risk Assessment for potential
exposure to this compound.
-------
Table 2
Constituents Detected in Off-site Residential Ground Water Wells*
Woodlawn Landfill, Cecil County, Maryland
(Page 1 of 2)
Constituent
Volatfles GIQ/L)
Acetone
Xylenes (total)
Vinyl chloride
Semivolafles G*g/L)
Bis(2-ethy1hexyl)pntnalate
Di-n-butylphthalate
Diethylphthalate
Metals (mg/L)
Aluminum
Arsenic
Barium
Beryllium
Cadmium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Range of
Concentrations'1
ND10-10
ND5-1
NDO. 12-0.6
ND10-5
ND10-3
N010-5
NDO.2-0.051
ND0.01 -0.002
0.0046-0.0596
NDO.005-0.0022
NDO.005-0.0034
ND0.01 -0.0072
NDO.05-0.0154
NDO.025-0.255
NDO. 1-6.075
NDO.003-0.0518
0.412-6.12
ND0.01 5-3.01 5
Frequency of
Occurrence
3/21
1/21
5/22
1/20
4/20
2/20
14/20
1/20
20/20
1/20
1/20
10/20
4/20
19/20
11/20
13/20
20/20
18/20
95% Upper
Bound
Concentration0
7.60
3.34d
0.17
6.93d
6.14d
6.86"
0.0655"
0.0067"
0.0268
0.00344d
0.00352"
0.00754"
0.0296"
0.0875
0.801"
0.00684
4.26
0.313
See footnotes at end of table.
-------
Table 2
(Page 2 of 2)
Constituent
Nickel
Silver
Vanadium
Zinc
Range of
Concentrations6
NDO.04-0.0124
ND0.01 -0.0032
NDO.05-0.0154
NOO.02-0.0613
Frequency of
Occurrence
2/20
2/20
17/20
16/20
95% Upper
Bound
Concentration
0.0263d
0.00668*
0.00976
0.0270
' Off-site residential ground water monitoring wells include those on parcels 309, 487,151, 530-17,
380, 233, 509, 506, 252, 530-23, 516. and 501.
b NO s Not detected at the concentration shown. In some instances constituents were detected at
trace concentrations below the detection limit As a result, some of the maximum range values are
below the detection limit
c The concentration of the 95 percentile upper bound of the mean calculated using one-half of
nondetect values. In instance where the upper bound value was greater than the maximum
concentration, the maximum concentration was used in the Risk Assessment.
"Maximum observed concentration was used in the Risk Assessment for potential exposure to this
compound.
-------
Tabled
Predicted Leachate Concentration of Constituents in Site Ground
Water From Subsurface Soils*
Woodlawn Landfill, Cecil County, Maryland
(Page 1 of 2)
Constituents
«.
VoJatites 0*g/L)
2-Butanone
1,1-Dichloroethane
1 ,2-Dichloroethane
1 ,2-Dichloroethene
2-Hexanone
4-Methyl-2-pentanone
Acetone
Chlorobenzene
Chloroethane
Ethylbenzene
Toluene
Xylenes (total)
Trichloroetnene
Vinyl chloride
Serrwolafles (MQ/L)
1 ,3-Dichlorobenzene
1 ,4-Dichlorobenzene
Benzoic acid
Bis(2-ethylhexyl) phthalate
CellB/C
Area
_b
0.59
0.11
0.13
0.12
0.22
9.0
1.37
6.66
0.028
0.012
0.12
0.010
3,242
-
-
42.5
5.54
Areas of the
Landfill
Excluding Cell
B/C
5.12
-
-
-
-
2.0
16.5
0.077
-
0.028
0.044
0.054
-
-
1.1
0.89
9.33
0.21
-------
Tabled
(Page 2 of 2)
Constituents
Butylbenzytphthalate
DHvbutylphthaiate
DkHXtylphthalate
N-Nitrosodiphenylamine
Pentachtorophenol
Phenanthrene
2-Methylnaphthalene
CeHB/C
Area
0.013
-
0.00026
0.46
0.0066
0.014
0.62
Areas of the
Landfill
Excluding Cell
B/C
0.020
0.0067
0.0000054
-
-
-
-
•Ground water concentrations were modeled for the leaching of subsurface soil
constituents into the underlying aquifer. (See Tables 6-9 and 6-10 of the Rl Report for
soil borings associated with each area).
"Dash indicates this compound not detected within the designated area.
-------
Table 4
Toxicfty Values for Chemicals of Potential Concern
(Page 1 of 5)
Compound
1,1-Dtehtoroethane
1 ,2-Dichlordbenzene
1,2-Dichkxoethane
1,2-Dtehloroethene
1,2-Otohkxopropane
1 ,3-Dtehkxobenzene
1 ,4-Dtehlorobenzene
2-Butanone
2-Methylnaphthalene
4-Methyl-2-pentanone
(MIBK)
4-Methylphenol
(p-cresoO
Acenaphthene
Acenaphthylene
Acetone
Aldrin
Alpha-BHC
Anthracene
Cancer Inhalation OralCSF Inhalation Rfd
Group CSF (mg/kg/d)-1-* (mg/kg/d)*
(mg/kg/d)-1*
C - - 1X10T1
4X10*
B2 9.1 X 10* 9.1 X 10*
- _ _ . _
B2 - 6.8 x1O» 1.1x10*
- - 4.2x10*
C - 1.4 x Iff1
9x10*
- _ _ -
- - 2x10*
- ' - - 1 X Iff1*
_ _ _ _
- - - -
3x10°-"
B2 1.7 X101 1.7 X101
B2 6.3x10° 6.3x10°
_ _ _ _
OralRfd
(mg/kg/d)*
ixlff1
9x10*
-
1X10*
-
9x10**
9x10**
5x10*
4x10*"
5x10*
5x10*
6x10*
3x10*"
1x1ff'
3x10*
-
Sxlff1
Refer to notes at end of table.
-------
Table 4
(Page 2 of 5)
Compound
Arsenic
Barium
Benzene
oenzo\a)anuvacene
Benzo(a)pyrane
Benzo(b)fluorantnene
Benzo(ghi)pefytene
Benzo{k)fluoranthene
BenzoicAcid
Beryllium
Bfc(2-
ethylhexyQpnthalate
BronxxSchkxomethane
Butylbenzylphthalate
Cadmium
Carbon Disuffide
Chlorobenzene
Chloroform
Chromium (Total)
Cancer Inhalation
Group CSF
(mg/kg/d)-'*
A 1.5x10'
- -
A 2.9 x 10*
B2
B2 6.1
B2
_
B2
- -
B2 8.4 X 10°
B2
B2
C
B1 6.3 x 10°
- -
- ' -
B2 ai x 10*
- '-
Oral CSF Inhalation Rfd
(mg/kpyd)-" (mg/kg/d)*
1.7S
1x10*
2.9x10-*
1.671
11.5
1.61
0.253"
0.7591
- -
4.3
1.4 X 10*
1.3 xia1 - .
- -
-
2.9x10*
5x10*
6.1 x 10*
5.7 x Iff7
Oral Rfd
(mg/kg/d)'
3x1CT*
7x10*
3x10**
3x10**
3x10*"
3x10*'
3x10**
4x10°
5x10*
2x10*
2x10*
2x10"'
5x1(T*
1X10T1
2x10=
1 x10*
1x10°
Refer to notes at end of table.
-------
Table 4
(Page 3 of 5)
Compound
Cancer Inhalation OraJCSF
OSF (mg/kg/dV1J
(mg/kg/d)-1-
Inhalation Rfd OralRfd
(mg/kg/d)' (mg/kg/d)*
Chiysene B2
Copper
DkvbutylphthaJate
Dt-n-octylphthalate
Dibenzo(ah)anthracene B2
Diethylphtnalate
DimethylphthaJate
Endosulfan -
Endrin ketone" -
Etfiytoeruene -
Fluoranthene -
Fluorene -
Gamma BHC (Lindane) C
Gamma Chtordane B2
Heptacrtkx B2
Indeno (1,2,3-cd)pyrene B2
Lead1 B2
Manganese
Mercury -
0.05061
Z9x1ff1
1.3x10°
4.5
1.3x10°
4.5x10°
1.1x10-*
8.6 x 10*
3x10**
3.7 XIO8*
1 X 10"
2x10*
3x10**
Bxlff1
1x10°
5x10*
3X1CT*
1x10"
4x10*
4x10*
3x10"*
6x10*
5x1(r.
3x10*«
5x10*
3 x 10*
Refer to notes at end of table.
-------
Table 4
(Page 4 of 5)
Cancer Inhalation OralCSF Inhalation Rfd OralRfd
Compound Group CSF (mo/kg/d)'1* (mg/kg/d)* (mg/kg/d)*
(mg/ko/d)-1*
Methylene Chloride B2 1.65x10* 7.5x10* asxlff1 6x10*
N-Nttrosodiphenylanftie B2 - 4.9x10*
•.
Naphthalene - - - - 4x10°
Nickel - - - - 2x10*
Perttachtarophenol B2 - 1.2 xlO1 - 3x10*
Phenanthrene _ _ _ _ 3x10**
Phenol - - - - 6x10'
Pyrene - - 3xlO*
Silver - - - - 5x10*
Tetrachloroethene 62 1.82x10* 5.1x10* - 1x10*
Thallium - - - - 7 x 10*
Toluene - - - 5.7 x1O1 2xlO1
Trfchtoroethene 82 1.7 xlO8 1.1 x 1O2 - -
Vanadium - - - 7x10*
Vinyl Chtonde A 2.9x1O1 1.9x10°
Xytenes (Total) - - - 8.6 xlO2 2x10°
Zinc - - - - 2x101
Refer to notes at end of table.
-------
Table 4
(Page 5 of 5)
•Cancer Slope Factors (CSB) and Reference Doses (RfDs) obtained from US. EPA, 1991, Health Effects
Assessment Summary Tables, Annual FY-1991, U.S. EPA, OSWER (OS-230), January, 1991, and IRIS
(January 1992).
'Value for 1,2-DicbJorobenzese used as a ssrropte based on analog.
•Value for Naphthalene used as a surrogate based on analogy.
"U.S. EPA, 1986, Superfnnd Public Health Evaluation Manual (SPHEM), U.S. EPA 540/1-86060.
•Value for Pyrene used as a surrogate based on analogy.
'Calculated at Benzo(a)pyrene relative potency equivalent level (dements, 1988).
•Conversion of 13 mg/I drinking water standard into reference dose.
"Value for Endrin used as a surrogate based on analogy.
'Potential health effects associated with exposure to lead evaluated using "Users Guide for Lead: A PC
Software Application of the Uptake/Biokinetic Model-Version 050," prepared by Environmental Criteria
and Assessment Office, Office of Health and Environmental Assessment, U.S. EPA, Cincinnati, Ohio,
January 1991.
-------
Tables
EPA Categories for Potential
EPA Category
Group A
Group B1
Group B2
Group C
Group D
Group E
Group Description
Human Carcinogen
Probable Human
Carcinogen
Possible Human
Carcinogen
Possible Human
Carcinogen
Not Classified
No evidence
Evidence
Sufficient evidence from
epidamiologic sfudifis to suooort a
causal association between
exposure and cancer in humans
Limited evidence in humans from
epidemiologic studies
Sufficient evidence in animals,
inadequate evidence in humans
Limited evidence in animals and/or
carcinogenic properties in short-
term studies
Inadequate evidence in animals
No evidence in at least two
adequate animal tests or in both
epidemiologic and animal studies
-------
Tables
Summary Health Risks and Hazards
From Exposure to Off-site Residential Ground Water*
Woodlawn Landfill, Cecil County, Maryland
«.
Receptor
Adult
Child
Adult
Child
INCREASED LIFETIME CANCER RISK
Routes of Exposure
Ingestion Dermal Contact" Inhalation6
1.6 x Iff4 6.1x10* 2.6 x Iff7
1.0 x Iff4 4.4 x1O* 4.6 x Iff7
NONCARCINOGENIC HAZARD INDEX
Routes of Exposure
2.3 0.000017 0.00012
2.6 0.000021 0.00036
Total
1.6 x10*
1.0x1(T*
2.3
2.6
"Compound-specific cancer risks and hazard indices are presented in Appendix N of
the Rl Report. See Table 2 notes for wells included in off-site residential risk
characterization.
6Dermal contact with organic constituents in ground water while showering.
Inhalation of volatilized constituents in ground water while showering.
-------
Table?
Summary Risk Estimates (Current Conditions) for Selected Child
and Adult Receptors Across Multiple Exposure Pathways
Woodlawn Landfill, Cecil County, Maryland
Exposure Scenario
Off-she Adult*
Off-site Child15
On-site Child6
Child On- and Off-site*
Exposure Scenario
Off-site Adult*
Off-site Child"
On-site Child6
Child On- and Off-site"
INCREASED LIFETIME
CANCER RISK
Routes of Exposure
Ingestion/Dermal Contact
1.6x10"*
1.0 X1O4
3.0x10*
1.0x10*
NONCARCINOGENIC
HAZARD INDEX
Inhalation
4.9 x 10'r
7.5 x 1(T7
2.4x1 OT10
7.5 x 1O7
Routes of Exposure
Total
1.6X10-4
1.0x10"*
3.0 X10"6
1.0x10**
Ingestion/Dermal Contact Inhalation
2.3 0.25
2.6 0.56
0.12 0.00088
2.7 0.56
Total
2.6
3.2
0.12
3.3
Includes exposure to off-site residential ground water and surface soil particulates
from areas of the landfill excluding Cell B/C.
blndudes exposure to downstream surface water and sediments, off-site residential
ground water, and inhalation of surface soil particulates from areas of the landfill
excluding Ceil B/C.
'Includes ingestion/dermal contact with on-site surface soil, seeps (sediment and
liquid), settling basin sediment, and inhalation of surface soil particulates while
trespassing on Site.
dAssumes child living in nearby residential area also trespasses on Site.
-------
Table 8
(Pagef of 2)
Summary Ground Water Risk Estimates (Future Conditions) for
Selected Child and Adult Receptors
Woodlawn Landfill, Cecil County, Maryland
INCREASED LIFETIME
CANCER RISK
Exposure Scenario
On-site Adutt-Leachate*
On-site Child-Leachate*
Orvsite Adult-Existing15
On-site Adult-Modelled*
Off-site Adult-Modelled"
Routes of
Ingestion/Dermal
Contact
7.3 x 10*
4.9 x 10*
5.6 x 10*
1.4x10*
1.7X10*
Exposure
Inhalation
5.0 x 10-3
8.6 x 103
2.3x1(T*
7.8 X1014
9.4 x 10*
Total
7.8 x 10*
5.8x10*
5.8 x 10*
1.5x10*
1.8X1CT3
NONCARCINOGENIC
HAZARD INDEX
Exposure Scenario
On-site Adult-Leachate'
On-site Child-Leachate'
On-site Adult-Existing6
On-site Child-Existing6
Routes of
Ingestion/Denmal
Contact
0.46
0.53
50
59
Exposure
Inhalation
0.0028
0.0084
0.021
0.064
Total
0.46
0.53
50
59
'Exposure to teachate-contaminated ground water using the Summers teachate
model, assuming a well is placed on the Site. The mean vinyl chloride concentration
in the Cell B/C sludge, based on the results for the 27 samples collected during the
RI/FS, is 290 M9/k9- However, the predicted teachate concentrations for this exposure
scenario are based on the 95% upper bound concentrations for constituents in just 5
Cell B/C sludge samples. The 95% upper bound concentration for vinyl chloride in
-------
Tables
(Page 2 of 2)
those 5 samples was 4.98 mg/kg. Therefore, the risks from exposure to leachate-
contaminated ground water are overestimated.
"Exposure to constituents currently present in the aquifer immediately below the
landfill, assuming a weH is placed in the center of the plume.
cExposure to modeled on-sfte vinyl chloride concentrations; 70 years in the future at
the highest on-srte weH (633 ug/L at well F-6).
dExposure to modeled off-site vinyl chloride concentrations; 70 years in the future at
the point along the site boundary predicted to have the highest concentration of vinyl
chloride (75 ug/L along Waibel Road east of Cell B/C).
-------
Table 9
Ground Water Oeamp Levds for OiiiiamlnaiiU
wfafaCBooogenfcHMlrV
r UILL^.
1 ,2*DlCnloroetnane
_
Tetrachloroethene
Tncnionxtncne
Vinyl Chloride
Bcnzo(a)anthnccne
Benzo(a)pyrene
B*nzo(b)fluonnthene
_ _
BenzoQcjfluoranthene
Chrysene
Pentachlorophenol
Aldrin
Alpha BHC
Heptachlor
Arsenic
Ma1
(art
5
5
5
2
.
02
.
-
6
.
1
.
•
0.4
50
MCU?
fcsft
0
0
0
6
.
0
.
.
0
.
0
•
.
0
-
Qean»L«»«l
CWQ
i(W*
1.5 OUtk-taMd)'
5
19QU
ai3(PQU
0.023 (MDUT
aiSCPQL)
0.17 (PQL)
6
1.SCPQL)
1
0.01 (PQL)
a013 OUtk-bMcd)
OD16 aUsk-based)
1 QUO* or background*.
whichever it freater
la*
L4X104
1AX104
1JOX104
24XI04
2AX104
93 X 10*
83X104
S.7X10*
1.0X10*
2-2X10*
X7X10*
10X10*
1.0X10*
1.0X10*
2.1 X 10* »
1 MCL- Maximua C
3 Kg/1: mkrofranu per liter
1 MCLG: Maximum ^
[Level
Level Goal
4 Excess lifetime carcinogenic risk associated with the cleanup leveL
5 PQL: Practical Quantiation Limit
•Risk-based: cleanup level based on caranofenic heahh effects
TMDL: Method Detection Limit
* IDL:
* EPA wffl determine the background level of anenk m the area of the Site bated on predesifn studies.
M Excess lifetime caranofenk risk from residential exposure to 1 pgA of arsenic.
-------
10
50
0*0
'MO:
'MCLG: M"*"
'Ground water
CoaaafantUNlGMl
developed ID accordance with the feQowinf approach. EPA. in <
rffea wffl bt baMd oo the Risk
uhadon with MDE. wffl dtttnnine
fafreundwattrintlMaraaafth«Sit*b«Mdaapnd«sifntaidi«. Tht
dtwdop dcanup k«d$ cocmpendinf to n ifptftt* haxard index Itn dm «r equal ID 1A Esdicquatioa
i • djffmat potribli Ste modfricn wfafa ngaid to tht btckyound k»dt fcr amafc and i
• tht daanuup 1m! for Entaulfni I in jif/L
• tht daamiB 1ml far ancnk in nt/L
ICd] • tht daanup tad for <
[Ma] • tht daanop kvtl far nunpncac in p(/L
(Hfl »tht daanup Itval far mtmoy in pf/L
M »tht daanup tod Cor vanadium in t&L
Tht number fa aach dancealnator fa aquadoM (la) tooajh Qb) bttow rapmina ih» <
chtmkal fa the mp«cth>t numgatar which fa ••nriitiil wid> a harard quiocknt (HQ) of IX) (Lc, a conctnttadco ef
L6«if/LofEnde«aUanIiia>MdatidwidiaHQorLa!). Ibe HQt far dMM cbtoucab azt pnMntad in tbt baidint
Tbt ckimip kvd« far iD cte<
ainintB wffl bt Mt each thtc
[Cdl/16
whtrt(A»] -
-------
Table 10
(Page 2 of 2)
(lb) [Endosulfan I]/1.6 + [Cd]/16 + [MnJ/160 + [HgJ/9.4 + M/220^ 1.0
where [Cd] <. 5 jjg/L
[Hg] <. 2
and the cleanup level for arsenic shall be the background arsenk concentration, pursuant to Table 9
unless EPA, in consultation with MDE, determines that such cleanup levels are mfeasible due to die natural occurrence
of manganese in local ground water. If EPA determines that me ground water cleanup levels that would satisfy
equations (la) or (lb), above, cannot be achieved because die background level for manganese approaches or exceeds
160 Mg/L, the cleanup levels will be set such that:
(2a) [Endosulfan IJ/1.6 + [AsJ/9.3 + [Cd]/16 + [HgJ/9.4 + [V]/220 <. 1.0
where [As] = 1 pg/L (die cleanup level for arsenic, pursuant to Table 9)
[Cd] <. 5
[Hg] < 2
and the cleanup level for manganese shall be die background manganese concentration
or,
(2b) [Endosulfan I]/1.6 + [Cd]/l6 + [Hg]/9.4 + [V]/220 <. 1.0
where [Cd] <. 5
[Hg] <
and the cleanup levels for arsenic and manganese shall be the background concentrations of arsenic and
manganese, respectively.
EPA, in consultation with MDE, will determine which of conditions (la) through (2b) shall be used to calculate die
ground water cleanup levels for contaminants with noncarcinogenic adverse health effects based on die background
levels of arsenic and manganese.
-------
Table 11
(Page 1 of 6)
Applicable or Relevant and Appropriate Requirements (ARARS)
and Guidance to Be Considered (TBCs)
for the Woodlawn Landfill Site
ARARorTBC
legal Citation
Classification
Summary of Requirement
Applicability to Selected Remedy
I. CHEMICAL SPECIFIC
A. Wa
1. Safe Drinking Water Act
42U.S.C. §§300fejseg.
a. Maximum Contaminant
Levels (MCU)
40 C.P.R §§141.1102 and
141.6I-.62
Relevant and Appropriate
MCU are enforceable standanb
for public drinking water
supply syitems which have at least
IS service connections or are used
by at least 25 persons. These
requirements are not directly
applicable since ground water at the
Site is used as a private drinking
water supply. However, under the
circumstances of this Site, MCU are
relevant and appropriate
requirements.
The NCP requires that remedial actions for
ground water that Is a current or potential
source of drinking water shall meet the
MCL for each site-related contaminant If
the Maximum Contaminant Level Goal
(MCLG) for that contaminant b set at a
level of zero and MCU are relevant and
appropriate under the circumstance* of
the lite. In addition, the discharge of
treated ground water to die on-dte stream
shall not result In an exceedance of MCU
In the waters of the strewn.
b. Maximum Contaminant
Level Goals (MCLGt)
40C.P.RII41.SO-.51
Relevant and Appropriate
MCLCs are non-enforceable health
goals for public water supplies
which have at least 15 service
connections or are used by at least
25 persons. Under the
circumstances of this Site, MCLGs
are relevant and appropriate
requirements.
The NCP require* that remedial actions for
ground water that Is a current or potential
source of drinking water shall meet non-
zero MCLGs for contaminants of concern
for which they exist, where they are
relevant and appropriate requirements. In
addition, the dbduirge of treated ground
water to the on-dte stream shall not result
In an exceedance of non-zero MCLGs In
the waters of the stream.
-------
Table 11
(Page 2 of 6)
ARARorTBC
Legal Citation
Classification
Summary of Requirement
Applicability to Selected Remedy
2. Clean Water Act;
Federal Ambient Water
Quality Criteria for the
Protection of Aquatic
Life
33 U.S.C. § 1314
Relevant and Appropriate
These are non-enforceable guidelines
established pursuant to Section 304 of
the dean Water Act that set the
concentrations of pollutants which are
considered adequate to protect aquatic
life. Federal ambient water quality
criteria may be relevant and
appropriate to CERCLA cleanups based
on the use* of • receiving water body.
These criteria are relevant and
appropriate because the Slate has
designated the on-*lte stream for
protection of aquatic life.
Contaminant concentrations in
treated ground water that will be
discharged to the on-sfte stream shall
not exceed the levels that will ensure
compliance with these criteria.
3. Maryland Surface Water
Quality Criteria
COMARs 26.08.02.03-.03-3
Relevant and Appropriate
These are criteria to maintain surface
water quality for public water
supplies, protection of aquatic life,
recreational purposes, and other
beneficial uses.
Contaminant concentrations In
treated ground water that will be
discharged to the on-slte stream shall
not eiceed the levels that will ensure
compliance with these criteria.
4. Integrated Risk
Information System
(UUS)
EPA Office of Research
and Development
To Be Considered
IRIS is an EPA data base containing
up-to-date health risk and EPA
regulatory Information for numerous
chemicals. IRIS contains only those
reference doses (RIDs) and cancer
slope factors that have been verified
by the RID or Carcinogen Risk
Assessment Verification Endeavor
Workgroups^ and b the preferred
source of toikity information.
These non-enforceable toxkity values
shall be considered where remedial
alternatives address risk-based criteria
or when setting standards for
S. EPA Health Advisories
on Drinking Water
EPA Office of
Drinking Water
To Be Considered
These advisories are non-enforceable
guidelines for public water supply
systems.
These advisories shall be considered
for remedial actions Involving ground
water monitoring, recovery and
treatment.
6* Health Effect!
it
EPA Environmental Criteria
and Assessment Office
To Be Considered
These are assessment* of chemical-
specific health effects that are based
on non-enforceable toikity data.
These assessments shall be considered
where remedial alternative* address
risk-based criteria or when setting
standards for cleanups.
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Table 11
(Page 3 of 6)
ARARorTHC
0. LOCATION SPECIFIC
A. The Endangered Species
Act oM 978
B. The Archaeological and
Historical Preservation
Act of 1974
C Maryland Wetlands
Regulation*
D. Procedure* for
Implementing the
Requirement! of the
Council on
Environmental Quality
on the National
Environmental Policy
Act
E. Ground Water
Protection Strategy of
1984
P. National Historic
Preservation Act of
1986
Legal Citation
16 U.S.C § 1531
50 C.F.R Part 402
16U.S.C§469
COMAR 08.05.04
40 CP.R Fart 6
AppendixA
EPA 440/6444)02
16U.S.C. §§470Q*e3.
36 C.F.R. Pan 800
Classification
Applicable
Applicable
Applicable
Applicable
To Be Considered
Applicable
Summary of Requirement
Act requires federal agencies to ensure
that any action authorized by an
agency Is not Ilkdy to Jeopardize the
continued existence of any endangered
or threatened spedet or adversely
affect Its critical habitat.
Requires actions to avoid potential
loss or destruction of significant
•dentine, historical, or archaeological
data
Protects nonddal wetlands of the State
other alteration and requires State
oversight and approval.
Thb Is EPA's policy for carrying out
the provisions of Executive Order
11990 (Protection of Wetlands). No
activity thai adversely afreets •
wetland shall be permitted If a
practicable alternative that has lets
effect Is available. If there Is no other
practicable alternative. Impacts must
be mitigated.
Identifies ground water quality to be
»4il»jMl «hu4M iMMnllal artinm
based on aquifer characteristics and
use.
Requires remedial action to take Into
account effects on properties Included
in or eligible for the National Register
of Historic Places and to minimize
harm to National Historic Landmarks.
Applicability to Selected Remedy
Potentially affected endangered
species have not been identified. The
remedial action shall be Implemented
so as not to adversely affect such
resources should any be Identified In
the future.
Actions shall be taken to mitigate any
advene effects on Identified off-site
historic resources that might result
from Implementation of the remedial
action.
These regulations shall be applicable
If construction of die cap or
discharge to surface water could
affect wetlands.
This shall be applicable If
construction of the cap or discharge
wetlands.
The EPA classification of the aquifer
at the Site (UA) shall be taken Into
consideration during design and
Implementation of the ground water
remedy.
Actions shall be taken to mitigate any
adverse effects on property eligible
for or Included on the National
Register of Historic Places that could
result from Implementation of the
remedial action.
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Table 11
(Page 4 of 6)
ARARorTBC
m. ACTIOW SPKOFIC
A. Control of Nobe
Pollution
B. Wakr
1. dean Water Act
National Pollutant
Dbcharge Elimination
Syitem and Maryland
Dbcharge Limitations
2. Criteria and Standard*
for Best Management
Practices
3. GukWIna Establishing
Test Procedures for the
Analysis of Mhiuna
4. Regulation of Water
Supply, Sewage Disposal
and Solid Waste
S. Stonnwater Management
«. Erosion and Sediment
Control
7. EPA Policy for Ground
Water Remediation at
Superfund Site*
Legal Citation
COMARl 26.02.03.02 A(2)
and B(2) and
COMAR 26.02.03.03 A
33 U.S.C. § 1342 and
COMARi 26.08.03.01 and
.07
40CF.R. Partl2S,
SubpartK
40C.F.R. Partl36
COMAR 26.04.04
COMAR 26.09.02
COMARs 26.09.01.01, .07 B
and .08 A
OSWER Directive
9355.4-03
Classification
Applicable
Applicable
Applicable
Applicable
Applicable
Relevant and Appropriate
Relevant and Appropriate
To Be Considered
Summary of Requirement
Provides limits on noise levels for the
protection of human health and
welfare.
Establishes effluent limitations for
discharges to waters of the State and
controls discharge of toxic substances
to surface waters.
Requires • dear description of a best
to be submitted as part of the NPDES
discharge permit application.
Establishes test procedures for analysis
of effluent discharged under the
NPDES program.
Establishes requirements for well
management plan and design and
construction of systems necessary to
control stormwater.
Requires preparation of an erosion
and sediment control plan for
activities involving land clearing,
grading and other earth disturbances
and establishes erosion and sediment
control criteria.
This policy recommends approaches to
ground water remediation using a
pump and treat system.
Applicability to Selected Remedy
* ~ f
Maximum Allowable Noise Levels
shall not be exceeded at the landfill
property boundaries during
construction and operation of the
remedy.
These limitations shall be applicable
to the discharge of treated ground
water to surface water.
Dbcharge of treated ground water to
surface water shall be In accordance
with a BMP program, although a
permit is not required.
These giiideUnen shaU be applicable
to the discharge of treated ground
water to surface water.
All wells shall be Installed and
maintained In accordance with Slate
requirements for construction and
•UVIMUIII1JCIII.
Stormwater shall be managed during
and after constuction to minimize
stream channel erosion, pollution,
tlltatian, sedimentation and local .
flooding.
These regulations shall apply to
clearing, grading, excavation and
capping activities at the Site.
This policy shall be considered during
the Implementation of the remedial
action.
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Table 11
(Page 5 of 6)
ARARorTBC
C Air
1. Air Emission Standards
for Process Venn
X Maryland Regulations
Governing Toilc Air
PoUuunu
3. Maryland Regulations
Governing Air Quality
(Volatile Organic
Compounds)
4. Maryland Regulations
Governing Air Quality
(Visible Emissions,
Paniculate*, Nuisance,
Odors)
S. Slate Implementation
Plan
6. Control of Air Emissions
from Air Stripper* at
Superfund Groundwater
Sites, June IS, 1989
Legal Citation
40 C.P.R. Part 264,
SubpartAA
COMAR 26.11.15
COMAR26.il .06.06
COMARs 26.11.06.02, .03,
.08 and .09
COMAR 26.11.19.02 G
OSWER Directive
935S.O-28
Classification
Relevant and Appropriate
Relevant and Appropriate
Relevant and Appropriate
Relevant and Appropriate
Relevant and Appropriate
To Be Considered
Summary of Requirement
Establishes requirements for process
vents associated with operations that
manage hazardous wastes with
organic concentrations of at least 10
parts per million weight.
Requires emissions of Toxic Air
Pollutants (TAPs) from new and
existing sources to be quantified;
establishes ambient air quality
standards and emission limitations
for TAP emissions from new sources;
requires best available control
technology for toxics (T-BACT) for
new sources of TAPs.
Provides air quality standards,
general emission standards and
restrictions for air emissions from
vents and treatment devices.
Provide air quality standards, general
emission standards and restrictions
treatment devices.
Requires reasonably available control
technology (RACT) for control of
emit more than 25 tons of VOCs per
year (in severe-lS oxone non-
attainment areas, under the dean
Air Act).
This policy guides the selection of
controls for air strippers at ground
water sites according to the air
quality status of the area of the site
(i.e., attainment or non-attainment
area).
Applicability to Selected Remedy
These regulations shall apply to
operation of the air stripper.
These regulations shall apply to
operation of the air stripper.
Emissions from the air stripper and
landfill gas vent* shall meet emission
limitations f or VOCs.
These regulations shall apply to
emissions from landfill gas vents.
An active gas collection system
equipped with RACT shall be
required If total VOC emissions from
the landfill exceed 25 tons per year.
This policy shall be considered In
determining if air emission controls
are necessary for the air stripper.
Sources most In need of controls are
those with emissions rates in excess
of 3 Ibsyhour or 15 Ibtyday or a
potential rate of 10 tons/year of total
VOCs.
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Table 11
(Page 6 of 6)
ARARorTBC
D. SoUd Watte
1. Sanitary Undflll •
Closure
2. Sanitary Landfills • Post-
Qosure Monitoring and
Maintenance
3. Conducting Remedial
Investigations/Feasibility
Studio for CERCU
Municipal Undflll Sites,
February 1991
• UABB^^MAB Mt^^^B
B* I^BKIMm WIH^
. cnaractensdcs of
Hazardous Waste
(Toiicity Characteristic)
2. Characteriidct of
Hazardous Waste
(Characteriitlcs of
Isnltabillty, Corrosivlry,
Reactivity)
3. Standards Applicable to
Generator! of Hazardous
Waste
4. Standards Applicable to
Transporters of
Hazardous Waste
5. RCRA Land Disposal
Restrictions
Legal Citation
COMARs 26.04.07.21 A, B,
DandE
COMARs 26.04.07.22 A, B
andC
EPA/540-P-91/OOI
40 C.P.R. 9261.24
COMARs 10.51.02.10, .11
and .12 (1985) and
COMARs 26.13.02.11, .12
and .13
COMARs 10.51.03.01, .03,
.04, .05 and .06 (1985) and
COMARs 26.13.03.01, .03,
.04, .05, .06 and .08
COMARs 10.51.04.01, .02,
.03 and .04 (1985) and
COMARs 26.13.04.01, .02,
.03 and .04
40C.F.RPart26B
Classification
Relevant and Appropriate
Relevant and Appropriate
To Be Considered
Applicable
Applicable
Applicable
Applicable
Applicable
Summary of Requirement
Establish minimum requirements for
closure of municipal landfills in the
State, including minimum cap
specifications.
Establish minimum post-closure
monitoring and maintenance
requirements for sanitary landfills In
the State.
Presents minimum specifications for
single-barrier caps for CERCLA
municipal landfill sites.
Establishes the criteria for
determining If a solid waste eihibits
the characteristic of toxidty.
Establishes the criteria for
determining If a solid waste exhibit
the characteristics of ignftability,
corrosivlry, or reactivity.
Establishes requirements for a
generator who treats, stores or
disposes of hazardous waste on-slte,
Including packaging, labeling,
manifesting, and recordkeeplng
requirements.
Establishes standards for persons
transporting hazardous waste off-
site, including manifesting,
recordkeeplng and (pill-notification
requirements.
Restrictions on land disposal of
hazardous wastes.-
Applicability to Selected Remedy
The specifications of the landfill cap
shall, at a minimum, comply with State
closure requirements.
Post-closure monitoring and
maintenance of the landfill shall
comply with theue minimum
requirements.
This guidance shall be considered In
evaluating the adequacy of the cap
design.
These criteria shall be used In
determining whether soils and
treatment residuals are subject to
RCRA hazardous waste regulations.
These criteria shall be used In
determining whether soils and
RCRA hazardous waste regulations.
On-site treatment and storage of any
treatment residuals or soils that exhibit
• characteristic of a hazardous waste
shall comply with these regulations.
These standards shall apply to any
hazardous wastes transported off-site.
These restrictions shall apply to land
disposal of any treatment process
wastes and contaminated soils that
exhibit a characteristic of a hazardous
waste.
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