PB99-963909
EPA541-R99-013
1999
EPA Superfund
Record of Decision:
Aberdeen Proving Ground
(Edgewood Area)
Aberdeen Proving Ground, MD
6/11/1999
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CLUSTER 3, SITE 3, OLD BUSH RIVER ROAD DUMP
BUSH RIVER STUDY AREA, EDGEWOOD AREA
ABERDEEN PROVING GROUND, MARYLAND
RECORD OF DECISION
FINAL
DISTRIBUTION RESTRICTION STATEMENT
APPROVED FOR PUBLIC RELEASE:
DISTRIBUTION IS UNLIMITED 2753-A-3
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CLUSTER 3, SITE 3
OLD BUSH RIVER ROAD DUMP
BUSH RIVER STUDY AREA
EDGEWOOD AREA
ABERDEEN PROVING GROUND
RECORD OF DECISION
FINAL
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CONTENTS
1.0 DECLARATION L
l.l SITE NAME AND LOCATION """!!!.'":!!!".'.' 1
1.2 STATEMENT OF BASIS AND PURPOSE . 1
1.3 ASSESSMENT OF SITE !
1.4 DESCRIPTION OF THE SELECTED REMEDY 1
1.5 STATUTORY DETERMINATIONS 2
2.0 DECISION SUMMARY 3
2.1 SITE NAME, LOCATION, AND DESCRIPTION 3
2.2 SITE HISTORY AND ENFORCEMENT ACTIVITIES 6
2.2.1 SITEHISTORY '5
2.2.2 ENFORCEMENT .!/".'.... 6
2.3 HIGHLIGHTS OF COMMUNITY PARTICIPATION 7
2.4 SCOPE AND ROLE OF THE OLD BUSH RIVER ROAD DUMP ... 7
2.5 SITE CHARACTERISTICS g
2.5.1 SUMMARY OF SITE SURFACE WATER CHARACTERISTICS .........."... 8
2.5.2 SUMMARY OF SITE SEDIMENT CHARACTERISTICS 8
2.5.3 SUMMARY OF SITE SOIL CHARACTERISTICS 9
2.5.4 SUMMARY OF GROUNDWATER CHARACTERISTICS .. 9
2.6 SUMMARY OF SITE RISKS 9
2.6.1 HUMAN HEALTH RISK 9
2.6.2 ECOLOGICAL RISK '.!'.l!""!"!'.!"""lO
2.7 REMEDIATION OBJECTIVES AND DESCRIPTION OF ALTERNATIVES '""".10
2.8 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 12
2.8.1 THRESHOLD CRITERIA "".'.." 12
2.8.2 PRIMARY BALANCING CRITERIA 14
2.8.3 MODIFYING CRITERIA 15
2.9 THE SELECTED REMEDY: SOIL CAP 15
2.9.1 DOCUMENTATION OF SIGNIFICANT CHANGES 16
2.9.2 PERFORMANCE STANDARDS 16
2.9.3 COMPLIANCE WITH ARARs 17
3.0 RESPONSIVENESS SUMMARY 21
3.1 OVERVIEW ...""".."."""^"^"Z. 21
3.2 BACKGROUND ON COMMUNITY INVOLVEMENT '.....'...'............. 21
3.3 SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC
COMMENT PERIOD AND APG'S RESPONSES 22
3.4 SAMPLE NEWSPAPER NOTICE ANNOUNCING THE PUBLIC
COMMENT PERIOD AND THE PUB LIC MEETING 41
MARYLAND DEPARTMENT OF THE ENVIRONMENT APPROVAL 42
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FIGURES
FIGURE 1.0 IRP EDGEWOOD AREA LOCATION MAP 4
FIGURE 2.0 BUSH RIVER STUDY AREA - CLUSTER 3 ..5
TABLES
TABLE 1. COMPARISON OF REMEDIAL ACTION ALTERNATIVES 13
TABLE 2 DESCRIPTION OF ARARs FOR SELECTED REMEDY 18,19,20
111
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ACRONYMS
APG Aberdeen Proving Ground
ARARs Applicable or Relevant and Appropriate Requirements
BRSA Bush River Study Area
STAG Biological Technical Assessment Group
COPCs contaminants of potential concern
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
DDTr total of pesticides DDT, ODD, and DDE
DSERT Defense Sites Environmental Restoration Tracking System
FAWQC Federal Acute Water Quality Criteria
FFA Federal Facility Agreement
FS Feasibility Study
HEAST Health Effects Assessment Summary Tables
HI hazard index
HQ hazard quotient
IRIS Integrated Risk Information System
IRP installation Restoration Program
LUCAP Land Use Control Assurance Plan
MCLs Maximum Contaminant Levels
MDE State of Maryland Department of the Environment
NCP National Oil and Hazardous Substances Pollution Contingency Plan
NPL National Priorities List
OU operable unit
PAHs polynuclear aromatic hydrocarbons
RAB Restoration Advisory Board
RBAs risk-based activities
RBCs risk-based concentrations
RCRA Resource Conservation and Recovery Act
RFA RCRA Facility Agreement
RFI RCRA Facility Investigation
RfD reference dose
RI remedial investigation
RME reasonable maximum exposure
ROD record of decision
TRY Toxicity Reference Value
UCL upper confidence limit
USEPA United States Environmental Protection Agency
IV
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1. THE DECLARATION
1.1 SITE NAME AND LOCATION
Cluster 3, Site 3
Old Bush River Road Dump
Bush River Study Area
Aberdeen Proving Ground
Harford County, Maryland
1.2 STATEMENT OF BASIS AND PURPOSE
This Record of Decision (ROD) document presents the remedial action selected to reduce the risks posed
by the Old Bush River Road Dump located at the Bush River Study Area at Aberdeen Proving Ground
(APG). The remedial action is intended to comply with the National Environmental Policy Act of 1969.
The selection of the remedial action was conducted in accordance with the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA) of 1980 as amended by the Superfund
Amendments and Reauthorization Action (SARA) of 1986. and the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP). This decision is based on the Administrative Record for
the site.
The Maryland Department of the Environment (MDE) concurs with the selected remedy at this site.
1.3 ASSESSMENT OF SITE
Actual or threatened releases of hazardous substances from this site, if not addressed by implementing
the remedial action selected in this ROD, may present an imminent and substantial endangerment to
public health, welfare, or the environment.
1.4 DESCRIPTION OF THE SELECTED REMEDY
The Cluster 3 cleanup is part of a comprehensive environmental investigation and cleanup currently being
performed at APG under the CERCLA program. APG is divided into 13 study areas that encompass
potential sources of contamination. The Old Bush River Road Dump of Cluster 3 is part of the Bush
River Study Area. The remaining clusters of the Bush River Study Area and other study areas are being
addressed as separate actions.
This action addresses the principal threats at the Old Bush River Road Dump by constructing a soil cap.
The soil cap reduces migration of contaminants by reducing infiltration and stabilizing the Old Bush
River Road Dump (OBRRD) to prevent erosion of surface soil, and attenuates the detonation of a 4.2-in.
chemical mortar. The selected remedy for the OBRRD will include long-term monitoring and
institutional controls which will include:
• The cap will be inspected for erosion, subsidence, vegetation density, and any other problems that
may impede performance of the soil cap. Sediments downgradient to the OBRRD will be sampled.
Final January 1999
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Because the remedy does not allow for unrestricted future use ot" the site, a review will be conducted
within 5 years after commencement of remedial actions to ensure adequate long-term protection of
human health and the environment is maintained.
Institutional controls will be implemented in the area. A 6-foot fence with warning signs will be
maintained around the OBBRD to restrict access. In addition, the restrictions will be included in
APG's Geographical Information System (GIS), which is used in documenting APG's Real ProDertv
Master Plan.
1.5 STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the environment, complies with federal and state
requirements that are legally applicable or relevant and appropriate to the remedial action, and are cost-
effective. The remedy uses permanent solutions and alternative treatment technologies to the maximum
extent practicable. The capping of the OBRRD reduces the mobility of contaminants by placing them in
controlled, monitored locations. However, it does not meet the statutory preference for treatment that
reduces the volume or toxicity of contaminants. With respect to landfill wastes, the potential presence of
unexploded ordnance (UXO) supports containment rather than a removal remedy. Because the remedy
does not allow for unrestricted future use of the site, a review will be conducted within 5 years after
commencement of remedial actions to ensure adequate long-term protection of human health and the
environment is maintained.
EDWARD L. ANDREWS Date
Major General, U.S. Army
Commander, U.S. Army Aberdeen Proving Ground
Abraham Ferdas 0ate
Director
Hazardous Site Control Division
U.S. Environmental Protection Agency, Region III
Final January 1999
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2. DECISION SUMMARY
2.1 SITE NAME, LOCATION, AND DESCRIPTION
southMstmi
Joppa, Magnoha, Ferryman, and Aberdeen. The Bush River divides APG into twTma n ar?J The
Edgewood Area of APG lies to the west of the river and the Aberdeen Area lies lo the east
response
NPL is EPA'S list
Considered Prioritie* for long-term remedial evaluation and
DefenSC Sites Environmental Restoration Tracking System
is djvidedk 1MO lhree areas: Nonhera Bush River- us
in lhe
t de. The
are
along ,he ditches and into Laudorick Creek
which drain into an
^"n"Cd fqUlfef(™J??7^' AThe s"rflclf ^"'fer thins and appears intermittently in this area and does
A confining layer composed of silts and clays separates the Canal Creek
units above it. The confining layer is continuous beneath the OBRRD.
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*
Mlchaelsvflle
Landfill NPL Site
Other Aberdeen
Areas
Chesapeake
Bay
Chesapeake
Bay
N
Installation Restoration Program Edgewood Area Location Map
Figure 1
4
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CLUSTERS
SITE 23: TRANSFORMER
STORAGE YARD
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2.2 SITE HISTORY AND ENFORCEMENT ACTIVITIES
2.2.1 Site History
The Bush River Study Area (BRSA) covers approximately 500 acres on a peninsula located in the
northeast portion of the Edgewood Area and is bounded on the north by Lauderick Creek, on the east and
south by Bush River, and on the southwest by Kings Creek. As early as 1918, portions of the BRSA were
used for training, test activities, chemical storage, and waste disposal. The southern part of the peninsula
was designated as "A-Field" and was used for artillery firing, training, testing, and for smoke and
incendiary munitions testing. It is not known if there was a munition impact area in the BRSA. During
World Wars I and n, the area was a main storage and transshipment depot for chemical-filled munitions.
The large dock on the southeastern boundary received foreign chemical munitions that were captured in
Europe and shipped to the Edgewood Area for testing and disposal. Dredging materials from the dock
channel were deposited onto a southern parcel of the peninsula (US AEHA 1989).
The OBRRD predates World War II and may have existed before 1917, when the Edgewood Area
became government property. A U.S. Geological Survey topography map from 1915 indicates a former
home site was located near the present location. There is no historic documentation on what was disposed
of at the site. Aerial photographs indicate the OBRRD was active in 1929 and continued to be active
through the early 1940s (USAEHA 1989). Inspections reveal that wastes were pushed out toward
Lauderick Creek over time, not all wastes were covered, and burning occurred at the site. The site is
currently inactive; according to aerial photographic evaluations, disposal activities last occurred during
the mid 1940s.
2.2.2 Enforcement
From 1984 to 1985, APG was evaluated as a potential National Priorities List (NPL) site under CERCLA
(USEPA 1985). In 1985, the Edgewood Area of APG was proposed for inclusion on the NPL; it was
listed on the NPL in 1990. In 1986, between the time of the proposed listing and the final listing, a
Resource Conservation and Recovery Act (RCRA) corrective action permit (MD3-21-002-1355) was
issued by the USEPA Region HI to address solid waste management units (SWMUs) in the Edgewood
and Aberdeen Area of APG. As part of the RCRA permit. U.S. Army Environmental Hygiene Agency
(USAEHA) performed a RCRA Facility Assessment (RFA) study for the Edgewood Area. In addition to
the RFA, the RCRA permit required that a RCRA Facility Investigation (RFI) be performed. However,
because of the final listing of the Edgewood Area on the NPL in 1990, the RFI was not completed.
Further investigations were to be performed under CERCLA.
After the Edgewood Area was placed on the NPL, a Remedial Investigation (RI) was initiated at Cluster
3. The Remedial Investigation recommended a Feasibility Study be conducted to evaluate potential
remedial alternatives for the Old Bush River Road Dump (Site 3).
The following documents provide details of the site investigations and cleanup actions at Cluster 3:
• USAEHA, 1989. RCRA Facility Assessment Report, Edgewood Area. Aberdeen Proving Ground.
Maryland, Report No. 39-26-0490-90.
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• APG, 1996. Bush River Study Area Wetlands Delineation Report, Aberdeen Proving Ground
Maryland, September 1996.
• APG, 1998. Remedial Investigation Report. Bush River Study Area, Cluster 3, Aberdeen Proving
Ground, Maryland, July 1998.
• APG, 1997. Focused Feasibility Study Data Report. Cluster 3. Site 3. Bush River Study Area
Aberdeen Proving Ground, Maryland, April 1997.
• APG, 1997. Focused Feasibility Study Data Report Addendum for Cluster 3, Site 3, Bush River Study
Area, Aberdeen Proving Ground, Maryland, October 1997.
• APG, 1998. Feasibility Study, Cluster 3, Old Bush River Road Dump, Bush River Study Area
Aberdeen Proving Ground, Maryland, July 1998.
• APG, 1998. Proposed Plan for Cluster 3, Site 3, Old Bush River Road Dump, Bush River Study Area
Aberdeen Proving Ground, Maryland, July 1998.
2.3 HIGHLIGHTS OF COMMUNITY PARTICIPATION
APG currently has a Restoration Advisory Board (RAB) that consists of representatives from local
government agencies, businesses, and the community groups playing an active role in the Installation
Restoration Program (IRP) process. One active group represented on the RAB is the Aberdeen Proving
Ground Superfund Citizens Coalition. The RAB meets monthly to discuss and concur on a variety of
topics regarding the environmental program at APG. The RAB has the opportunity to review and
comment on all documents addressing the IRP sites. APG offered opportunities for public input and
community participation during the RI, Feasibility Study (FS) and Proposed Plan for Cluster 3 Site 3
Old Bush River Road Dump. The Proposed Plan was made available in the Administrative Record'
which was housed in public facilities off the APG installation. The notice of availability of the Proposed
Plan was published in The Aegis (Harford County local paper), the Kent County News (Kent County local
papers), The Avenue and The Essex Times (Baltimore County local paper), and the Cecil Whig (Cecil
County local paper) on July 29, 1998, and in the APG News (installation newspaper) on July 30 1998 A
public comment period was held from July 31 through September 14, 1998. APG held a public meeting
on August 18, 1998, at 6:30 p.m. at the Edgewood Senior Center. Edgewood, Maryland, to discuss the
i"SF J™**"?*8 that °CCUrTed at the °ld Bush River Road DumP- Representatives from the
UMiPA, MDE, and APG were present to answer questions about APG, OBRRD, and the recommended
alternative.
A summary of questions and responses from the public meeting is included in the Responsiveness
activlties fulfin the requirements of Section
2.4 SCOPE AND ROLE OF THE OLD BUSH RIVER ROAD DUMP OPERABLE UNIT
remedy f°r SUrface soiL surface water- Md sediment, at the OBRRD
represents one component of a comprehensive environmental investigation and cleanup
being performed under the IRP at APG. Protectiveness of this action will be evaluated during the five-
year review process. Long-term monitoring data will be available for those reviews.
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The purpose of the remedial action is to prevent future environmental impacts as a result of the migration
of contaminants to areas where humans and environmental receptors may be exposed.
A study of groundwater in the BRSA is ongoing. Groundwater contamination is not addressed in this
ROD. Subsequent actions will evaluate the risks and need for action based on groundwater
contamination.
2.5 SITE CHARACTERISTICS
The Cluster 3 RI report investigated 2 sites: the OBRRD (Site 3) and the Transformer Storage Area (Site
23). The RI concluded that there would be no further action for the surficial aquifer, since it meets the
requirements of Type in aquifer under the Code of Maryland Regulations, and cannot be considered a
potential potable water supply. Also, there would be no further action at the Transformer Storage Area, a
removal action was completed in 1991. However, it did recommend a Feasibility Study for the Old Bush
River Road Dump.
The OBRRD is approximately 1.56 acres. The site contains many areas where surface debris is either
uncovered or partially covered. There is no documentation on the types of wastes placed into the Old
Bush River Road Dump. However, there is potential for hazardous materials. Lead contaminated soil;
discarded laboratory supplies and glassware; recovered UXO; chemical plant process equipment; burned
remnants of gas mask canisters; concrete pieces and bricks; metal objects, rods, wire, and pipes; as well as
other demolition and household waste have been found at the site. The types of UXO which were used
during this era and may have been disposed of in the dump include 75 mm shells, Livens projectors, and
4.2 inch mortar rounds.
The Army completed a removal action involving the placement of a fence around the OBRRD in May of
1996.
2.5.1 Summary of Site Surface Water Characteristics
Fourteen surface water samples (seven locations in two rounds) were collected during the field
investigations. Only two samples had exceedences above the Fresh Acute Water Quality Criteria
(FAWQC). The FAWQC was used to evaluate the groundwater's potential impact on surface water. The
two samples had exceedences of lead (94.3 and 115 ug/L) just above the FAWQC of 82 ug/L.
2.5.2 Summary of Site Sediment Characteristics
Sediment samples were compared to USEPA Biological Technical Assessment Group (BTAG) screening
criteria for sediment, which are based on ecological risk values. Sediment samples showed elevated levels
of lead (484 mg/kg), nickel (125 mg/kg), and zinc (669 mg/kg) relative to BTAG criteria. Six sample had
concentrations of beryllium (up to 5.8 mg/kg) which where above the human health screening criteria
(0.150 mg/kg) [EPA Region HI Risk Based Concentrations residential (RBCs)]. The elevated levels of
metal in the sediment are the same metals that are present on top of the landfill and the northeastern
pushout area. Therefore, it appears the sediment contamination has come from past or continuing
slumping and erosion of the surface of the OBRRD.
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2.53 Summary of Site Soil Characteristics
Two out of seven soil samples had concentrations (4,700 and 3.120 mg/kg) above the EPA ecological
screening level for lead (400 mg/kg). These samples were taken from the bum areas on the landfill. The
surface soils on the OBRRD contain elevated levels of metals compared to samples adjacent to the Dump.
Metals such as copper (13,600 mg/kg), nickel (42mg/kg). zinc (669 mg/kg), mercury, and arsenic (49.2
mg/kg) have been found at elevated levels on the landfill. However, these levels of contamination are
below industrial risk based screening criteria.
The burn areas are sparsely vegetated, and the soil in these areas is discolored. Elevated levels of lead
(484 mg/kg) were found in a soil sample near a burn area. Lead was also found in soil samples taken
from the burn areas (4,700 and 3,120 mg/kg). It also appears that erosion and soil slumping in this area
have transported contaminated soil and sediment from the landfill into the streams and wetlands.
2.5.4 SUMMARY OF GROUNDWATER CHARACTERISTICS
Five deep geotechnical borings drilled in BRSA indicate there are three distinguishable aquifers separated
by confining units. The three aquifers are the surficial aquifer, the Canal Creek Aquifer, and the lower
confined aquifer (APG 1997). Wells and borings drilled in Cluster 3 show that a water-bearing fill zone
exists within the northeast portion of the OBRRD and along the two perennial streams bordering the
Dump. The surficial aquifer thins and appears intermittently in this area. The Canal Creek Aquifer is
under confined conditions. In the vicinity of the Dump, the aquifer dips to the east. It is encountered at
elevations around -2 to -13 ft mean sea level (MSL). It varies in thickness from 5 to 20 ft The Canal
Creek Aquifer outcrops and is recharged west of the Dump. Groundwater flow in the Canal Creek
Aquifer is to the northeast. A confining layer composed of silts and clays separates the Canal Creek
Aquifer and the water-bearing units above. The confining layer is continuous beneath the Dump. The
confining layer varies in thickness from 2 to 30 ft. Any contamination migrating downward is contained
in the fill zone and cannot enter the underlying aquifers. Groundwater contamination in the Bush River
Area is being addressed in a separate Operable Unit and is not addressed in this ROD.
2.6 SUMMARY OF SITE RISKS
APG conducted a human health and ecological risk assessment as part of the RI to estimate the
probability and magnitude of potential adverse human health effect and environmental effects from
contaminants at the site.
2.6.1 Human Health Risk
The human health risk assessment evaluated each contaminant detected in the groundwater, surface water,
soil, and sediment samples collected during the RI and the Feasibility Study (FS). The contaminant
concentrations were compared to the EPA RBCs and background concentrations. Contaminants above
screening criteria were evaluated in the risk assessment.
The human health risk assessment evaluated eight contaminants of concern The contaminant of concern
identified in groundwater samples was cadmium. The contaminants of concern identified in soil samples
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were benzo(a)pyrene (a semivolatile organic compound). 4.4'-DDT, arsenic, copper, iron, beryllium,
antimony, lead, p-chlorophenylmethyl sulfone. and 2-hexone.RBC. Beryllium, iron, 4,4'-DDT, arsenic,
copper, iron, benzo(a)pyrene, beryllium, chlordane, 2-methylnaphthiene, phenanthrene, lead, magnesium,
and antimony were identified as contaminants of concern in the sediment. Arsenic was identified in
surface water. See the FS for more information on contaminants of concern (Section 1.3.3.2, page 1-16).
Health risk levels, determined using EPA guidance to ensure that conservative estimates of potential
health effects are determined, differ depending on the assumed land use because human exposures differ
with land use. A conservative estimate of risk was developed incorporating the potential exposure
pathways and includes ingestion and dermal absorption of the affected media.
The human health risk assessment concluded the conservative estimate of potential carcinogenic risk of
each chemical detected at Cluster 3 was below I x 10"6 . which falls within EPA's acceptable risk range.
In addition, the hazard indices for each exposure pathway at the OBRRD were less than one. The
OBRRD property is in an industrial area, however there is military residential housing north of the
OBRRD. A review of historical information and recent UXO surveys indicates that detonation of a 4.2-in.
chemical mortar located at the existing ground surface is the worst case scenario for risk to human health.
The risk assessment considered the proximity of the residential property to the landfill. The selected
remedial actions will be protective of the residents.
2.6.2 Ecological Risk
An ecological risk assessment was performed to assess potential adverse effects from Cluster 3 to
ecological .receptors. Absolute conclusions cannot be made regarding the potential for chemicals at
Cluster 3 to adversely affect ecological resources because of the many uncertainties surrounding the
estimates of toxicity and exposure. However, several general conclusions were made regarding the
potential for adverse effects to ecological resources.
The results of the sediment analysis indicate the greatest potential for adverse effects to the benthic
organisms are likely posed by the creek sediments in the freshwater marsh. The results of the surface
water analysis indicate a limited potential for adverse effects to aquatic life from the surface water of the
creek in the freshwater marsh.
The analytes noted to exceed ecological criteria include ODD, lead, and nickel, which were characterized
as having the greatest potential for adverse effects to benthic organisms in the RI Ecological Risk
Assessment.
2.7 REMEDIATION OBJECTIVES AND DESCRIPTION OF ALTERNATIVES
Remedial action objectives (RAOs) developed for the OBRRD are to:
« prevent direct contact with the Dump's soil and waste,
• reduce infiltration into the Dump and possible migration of contamination,
• prevent erosion of surface soil from the Dump to surface water and sediment,
" contain any potential risk of detonation of unexploded ordnance by providing a physical barrier to the
release of either chemicals or fragmentation, and
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• reduce/ eliminate risk to ecological receptors.
The EPA's Presumptive Remedy for CERCLA Municipal/Military Landfills was used in developing
remedial action alternatives. The presumptive remedy process involves streamlining the FS to analyze
only containment options and no-action alternative. Several remedial action alternatives were developed
from the general response action of containment. The following remedial action alternatives were
developed:
ALTERNATIVE 1: No Action
Annual O&M Cost $17,162
Present Worth $328,323
CERCLA, as amended, and the National Contingency Plan require that the "no action" alternative be
evaluated at every site to establish a baseline for comparison. Remedial action is not included as part of
the "no action" scenario; however, long-term monitoring will be included to determine if contaminants
migrate from the landfill.
ALTERNATIVE 2: Composite Cap
Capital Cost $1,257,628
Annual O&M Cost $23,222
Present Worth $1,701,884
The purpose of the composite cap is to prevent infiltration by layering geosynthetic material to drain
water off the OBRRJD, prevent infiltration through the composite layers, vent gases produced from the
OBRRD, and contain any potential risk of detonation of a buried 4.2 inch chemical mortar. This type of
cap is commonly used for municipal and hazardous waste landfills. A combination of a low-permeability
geosynthetic clay layer and a flexible geomembrane would be installed as a highly effective means of
reducing the potential for infiltration of water into the OBRRD, thereby reducing the possibility of
contaminant migration.
ALTERNATIVE 3: Soil Cap
Capital Cost $881,856
Annual O&M Cost $21,782
Present Worth $1,298,564
The purpose of the soil cap is to reduce infiltration, stabilize the OBRRD to prevent erosion of surface
soil, and contain any potential risk of detonation of a buried 4.2 inch chemical mortar. A vegetative cover
is established to minimize erosion, enhance evapotranspiration, and minimize infiltration. Establishing
and maintaining a good vegetative cover is important in the performance of this alternative.
ALTERNATIVE 4: Vegetative Barrier Cap
Capital Cost $819,236
Annual O&M Cost $ 19,652 to $54,963 (varies by year)
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Present Worth $1,308,699
The vegetative barrier cap, in conjunction with a soil cap, is an innovative technology used for landfill
closure. This technology uses selected trees or grasses to further reduce infiltration into the OBRRD
through transpiration. Although trees and certain grasses can increase the surface roughness of a landfill
and thus increase infiltration, the transpiration rates should compensate for the added amount of
infiltration entering the surface of the OBRRD. This technology uses alternative vegetation such as
poplar trees and grasses to prevent precipitation from percolating beyond the root zone. This alternative
will also contain any potential risk of detonation of a 4.2 inch, chemical mortar round.
2.8 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The remedial alternatives presented in Section 2.7 were evaluated in accordance with the regulatory
requirements of CERCLA using the nine criteria specified by USEPA as set forth in the NCP. The nine
criteria are categorized into three groups: threshold criteria, primary balancing criteria, and modifying
criteria. The alternative that is ultimately implemented must satisfy the threshold criteria, which are the
most important. Primary balancing criteria weight the major trade-offs among alternatives. Modifying
criteria are considered after conclusion of the public comment period. This section summarizes the
relative importance of each remedial alternative with respect to these criteria. Table I presents a
comparison of remedial action alternatives for the OBRRD.
2.8.1 Threshold Criteria
• Overall Protection of Human Health and the Environment. All of the alternatives except
Alternative 1 (No Action) provide long-term protection of human health and the environment.
Alternative 4, Vegetative Barrier Cap, is an innovative technology used specifically to prevent
infiltration of precipitation into the Dump's material using vegetation, specifically poplar trees.
Although this is not a proven technology, the vegetative barrier is a variation of Alternative 3, Soil
Cap. Existing information on poplar trees suggests that this technology would be effective long term
and provide protection to human health and the environment. The vegetative barrier cap has the
fewest short-term impacts during construction. The composite cap and soil cap require consolidation
of waste in the northeast portion of the landfill, whereas the vegetative barrier cap does not. The
possibility of UXO presents problems in conducting intrusive work in and around the Dump and
creates short-term risks to workers. The composite cap also requires grubbing of trees and woody
vegetation to prepare the surface of the landfill. This also creates more short-term risks to workers.
The soil cap and vegetative cap do not require grubbing. Existing wetlands will be destroyed with all
three alternatives. However, wetlands will be reestablished to offset long-term impacts. All the
alternatives except Alternative 1 (No Action) meet all ARARs. Alternatives 2, 3, and 4 meet RAOs
for the Dump. These three alternatives (1) prevent exposure to the Dump, (2) reduce infiltration and
subsequent contaminant migration, (3) prevent erosion of surface soil and risk to ecological receptors,
and (4) contain any potential risk of detonation of a UXO and prevent chemical or fragmentation
release. Alternative 1, No Action, does not meet any of the RAOs and does not meet chemical-
specific ARARs.
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Remedial
alternatives
Alternative 1, No
Action
Alternative 2,
Composite Cap
Alternative 3,
Soil Cap
Alternative -4,
Vegetative-
Barrier C.'ap
_ .„»«. *. WU...U.UIMJII 01 remedial action alternatives for the Old Rush, RjYPr RnaH Hiimn
Evaluation criteria
Overall protectiun of
human health and the
environment
Does not provide adequate
protection; AKAKs are not
met; RAOs are not met
High level of protection;
possibility of more ihort-
(erm impacts than other
alternatives;
meeis AKAKs and RAOs
Protective of human health
and the environment,
short-term impacts fioiii
excuvulion; meets ARARs
and KAOs
Innovative technology;
pci loi mancc data aic not
available, use ol vegetation
to decieuse inlilli.ilioii:
lewcbt shoii-leim impacts;
il cllcclivc. will inccl
ARARs and RAOs
Compliance with
ARARs
Will not meet
Will meet
Will meet
Will iikvi
Long-term effectiveness
and permanence
Risks are not reduced
High degree of reliable
long-term protection to
human health and
environment; commitment
to O&M is required
Reliable long-term
protection to human health
and environment;
commitment to O&M is
required
l'imide» long-term
piotcclioii ID human hcalih
and environment; high
degiec ol O&M is required.
••—
Reduction of loxicity,
mobility, and volume
No reduction of loxicity,
mobility, or volume
Reduces contaminant
mobility but not foxicily
or volume
Reduces contaminant
mobility but not lox icily
or volume
Reduce^ contaminant
mobility but nut loxicity
or volume
Short-term effectiveness
No impacts to workers or
community; no reduction of
risk in short-term
Greatest shon-lenn impacts
because it requires the most
excavation; effective as soon
as constructed
Some slmit-lerm impacts
from excavation; effective as
soon as grassy vegetation is
established
Fewest shun term impact-,
iHxatise least amount ol
excavation, lake.*, luiigci to
establish vegetation and
effectiveness
Implementability
Easily implemented,
installation of
monitoring wells
Most difficult to
implement because of
the use of geosynthetics;
however il is a well-
developed technique;
materials and equipment
readily available
Least difficult to
implement; materials
and equipment readily
available
t:a.->> ID implement,
however, more dilliculi
to maintain, luiwevci.
materials may not Ik;
leadily available, high
degieeol O&M.
Cost
Long-term Monitoring
0&M:JJ328,323
NPW:^328,323
Capital: $1,257,628
O&M: $444,256
NPW:$ 1,701, 884
Capital: $881,856
O&M: $4 16,707
NPW:$ 1,298,564
Capital. MIY.-'.id
O.VM 14XV.-K.1
NPW..$l.1l)8.MW
13
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• Compliance with Applicable or Relevant and Appropriate Requirements . Alternatives 2, 3, and
4 comply with all identified ARARs. Alternative 1 does not comply with all ARARs. Alternative 1
does not comply with chemical-specific ARARs or RCRA Hazardous Waste Landfill requirements,
which set forth criteria for cover systems for solid waste landfills.
2.8.2 Primary Balancing Criteria
" Long-term Effectiveness and Permanence. Alternatives 2 and 3 provide reliable, long-term
protection of human health and the environment. None of the alternatives provides permanence
because the waste at the Dump is not treated. As discussed earlier. Alternative 4, Vegetative Barrier
Cap, is an innovative technology used to prevent infiltration into the Dump's material using poplar
trees and grassy vegetation. Information on poplar trees suggests they would be effective long term.
Alternative 1, No Action, is not effective long term and is not permanent. Commitment to O&M is
essential in the long-term effectiveness of these alternatives. Alternative 4, Vegetative Barrier Cap
will require the most maintenance of all three alternatives.
" Reduction of Toxicity, Mobility, and Volume. Alternatives 2, 3, and 4 reduce contaminant
mobility by reducing surface water infiltration and limiting the transport of contaminants via surface
water runoff. According to the HELP Model, the composite cap prevents infiltration better than the
soil cap. However, both are comparable in preventing erosion of surface soils. No reduction in
toxicity or volume of landfill contaminants is achieved with any of the alternatives because the waste
at the Dump is left in place. Again, the vegetative barrier cap is an innovative technology, and
performance data are not available on reduction of infiltration rates. However, the technology using
poplar trees suggests that infiltration will be greatly decreased and mobility would then be reduced
during the growing season. Alternative I, No Action, does not reduce toxicity, mobility, or volume.
" Short-term Effectiveness. The vegetative barrier cap has the fewest short-term impacts during
construction. The planning stages of all three alternatives include minimizing excavation. The
possibility of UXO presents problems in conducting intrusive work in and around the Dump and
creates short-term risks to workers. The composite cap, soil cap, and vegetative barrier cap require
consolidation of waste, which will require excavation in the northeast portion of the landfill. All
three alternatives require rerouting of the streams, which involves minimal excavation. The
composite cap also requires grubbing of trees and woody vegetation to prepare the surface of the
landfill. This also creates more short-term risks to workers. The soil cap and vegetative cap do not
require grubbing. The vegetative barrier cap may take longer to become effective than the other
alternatives. As the poplar trees grow, they absorb more water; therefore, this alternative may not be
as effective as the composite cap and soil cap within the first year. The composite cap and soil cap
are very similar with respect to short-term effectiveness. Alternative 1 is not effective short term and
has no short-term impacts to site workers.
1 Implementability. Alternative 1, No Action, is the easiest to implement. Of the other alternatives,
Alternative 3, Soil Cap, is easier to implement. Conventional construction equipment and techniques
are used, and materials are readily available. The vegetative cap is easy to construct. However,
because this technology is patent pending, materials may be available from only one service
contractor. However, most of the work will require conventional construction equipment. The
Vegetative Barrier Cap will also require the greatest amount of maintenance. The composite cap is
14
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more difficult to implement than the other alternatives because of the use of geosynthetic materials.
However, composite caps using geosynthetics have been used at many hazardous waste sites and the
technique is well developed. Extreme weather conditions can delay implementation of all the
alternatives, particularly Alternative 2, Composite Cap.
• Cost. Following are the costs of the alternatives from least expensive to most expensive:
Alternative 1,No Action $328,223
Alternative 3, Soil Cap $ [ ,298,564
Alternative 4,Vegetative Barrier Cap $1,308.699
Alternative 2, Composite Cap $ 1,701,884
2.83 Modifying Criteria
• State/Agency Acceptance. Maryland Department of the Environment does not accept Alternative I.
Alternative 3 is acceptable because this alternative prevents direct contact with the OBRRD soil and
waste, reduces infiltration into the OBRRD and possible migration of contamination, prevents erosion
of surface soil, contains the detonation of buried UXO. and reduces risk to ecological receptors.
- Community Acceptance. The community has accepted Alternative 3 during the public comment
period.
2.9 THE SELECTED REMEDY: SOIL CAP
The soil cap, is the selected remedy for remediation of the Old Bush River Road Dump. The soil cap
reduces migration of contaminants by reducing infiltration, stabilizing the OBRRD to prevent erosion of
surface soil, and contain the risk of detonation of a 4.2-in. chemical mortar. A review of historical
information and recent UXO surveys indicates that detonation of a 4.2-in. chemical mortar located at the
existing ground surface is the worst case scenario for risk to human health. The Conventional Weapons
Effects Model shows that a burial depth of 3 ft is sufficient to contain the blast produced by a 42-in
chemical mortar. The soil cap will consist of two layers. The first layer will be a minimum 3 ft
foundation layer. The second layer will be a minimum 6 inch layer of topsoil to support vegetation
Therefore, the soil cap will be a minimum of 3 feet 6 inches. The HELP model, which is used by EPA to
understand infiltration through landfill caps, shows that a soil cap with good vegetative cover will reduce
infiltration of precipitation into the landfill by 76%.
Institutional controls will be implemented in the area. A 6-foot fence with warning signs will be
maintained around the OBBRD to restrict access. In addition, land use, access, and excavation
restrictions will be included in APG's GIS, and in APG's Real Property Master Plan. All use restrictions
will be incorporated in any real property and/ or real estate documents necessary for transferring
ownership from the Army, in the unlikely event that the Army transfers the property. The real property
and/ or real estate documents would also include a discussion of the NPL status of the site, as well as a
description of the contaminants at the site. Quarterly inspections will be performed and the Army will
certify to EPA on an annual basis that the institutional controls are functioning. A site-wide LUCAP is
being developed for APG, and will incorporate Cluster 3.
15
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This alternative meets the Remedial Action Objectives of (1) preventing direct contact with the OBRRD
soil and waste, (2) reducing infiltration into the OBRRD and possible migration of contamination, (3)
preventing erosion of surface soil, (4) contain the risk of detonation of buried UXO, and (5) reducing risk
to ecological receptors. A comprehensive monitoring plan for the site will be developed through a
cooperative effort between the U. S. Army APG. USEPA. and MDE, after this ROD is finalized. The
plan will approved by the USEPA and be available in the administrative record, as required by CERCLA.
2.9.1 DOCUMENTATION OF SIGNIFICANT CHANGES
There have been no significant changes since the Proposed Plan was presented.
2.9.2 PERFORMANCE STANDARDS
" The soil cap will consist of two layers. The first layer above the OBRRD surface will be a minimum
3-ft foundation soil layer designed to contain a blast of buried UXO and prevent an acute release of
chemical gases. As with the composite cap, a review of historical information and recent UXO
surveys indicates that a detonation of a single 4.2-in. chemical mortar located at the existing ground
surface is the worst case scenario for risk to human health, since chemical munitions do not
sympathetically detonate. The Conventional Weapons Effects Model shows that a burial depth of 3 ft
is sufficient to contain the blast produced by a 4.2-in. chemical mortar. The soil cap, which will
consist of two layers, will be a minimum of 3 feet 6 inches.
• The second (top) layer will be a minimum '/2-ft-thick layer of topsoil. The cap will be thicker in some
areas to bring the surface of the cap to a level grade with a 4% slope to facilitate drainage. A
vegetative cover will be established to minimize erosion, enhance evapotranspiration, and minimize
infiltration. Surface and subsurface wastes outside the limits of the OBRRD cap will be consolidated
and placed under the cap limits
» Both adjacent streams will be filled because of their proximity to the OBRRD. The streams will be
relocated around the slope of the OBRRD; the northern stream will be moved to the north and the
eastern stream to the east. Both streams support emergent wetland vegetation that will be destroyed
during construction. State regulations and policy on destruction of nontidal wetlands dictate that
emergent wetlands must be reestablished on a minimum 1:1 basis. The area of the wetlands that will
be disturbed and reestablished onsite is approximately 0.35 acres.
• Long-term monitoring will be performed for a minimum of 30 years to ensure the long-term
performance of the soil cap. The cap will be inspected for erosion, subsidence, vegetation density,
and any other problems that may impede performance of the soil cap. Sediments downgradient to the
OBRRD will be sampled quarterly for the first year, and annually thereafter.
• Because the remedy does not allow for unrestricted future use of the site, a review will be conducted
within 5 years after commencement of remedial actions to ensure adequate long-term protection of
human health and the environment is maintained. At that time the need for additional 5 year reviews
will be evaluated.
• Institutional controls will be implemented in the area. A 6-foot fence with warning signs will be
maintained around the OBBRD to restrict access. In addition, land use, access, excavation
16
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restrictions will be included in APG's GIS. and in APG's Real Property Master Plan. In addition, the
Director of APG's Directorate of Safety, Health, and the Environment will certify to EPA on an
annual basis that there have been no violations of the prohibitions. If a violation has occurred, a
description of the violation and corrective actions to be taken will be provided.
2.9.3 COMPLIANCE WITH APPLICABLE OR RELEVANT APPROPRIATE
REQUIREMENTS
The selected remedy meets or exceeds all ARARs. The specific ARARs are listed in Table 2: Description
of ARARs for Selected Remedy.
17
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Table 2 Description of ARARs for Selected Remedy
Media
Require
ment
Synopsis of
Requirement
Action to be Taken to Attain Requirement
Status
Ground
Water
Chemical
And
Action
Federal Clean
Water Act
40 CFR Part 131
Water Quality
Standards
The objectives of the Clean Water Act is to restore and
maintain the chemical, physical, and biological integrity
Of the nation's waters. This objective is achieved through
The control of discharges of pollutants to navigable waters.
This control is implemented through the application of federal,
state, and local discharge standards. CERCLA § 121 states
that hazardous substances, pollutants, or contaminants left on-
site at the conclusion of the remedial action shall attain federal
water quality criteria. Water quality criteria are based on the
potential use of the stream. Therefore, FAWC are applicable
for cleanup standards for the streams near the Dump.
Applicable
Ground
Water
Chemical
Maryland Water
Quality
COMAR
26.08.02.01-08
Maryland water quality regulations designate uses of the
waters of the state and establish water quality standards to
protect the designated uses. This regulation is applicable and
will be met by constructing a soil cap on the Dump minimizing
the potential for leachate to degrade surface water.
Hazardous
Waste
Location
Maryland Natural
Resources Code
annotated
Sections 8.1801 to
8.1816
Because Site 3 is within the I.OOO-ft buffer of the Chesapeake
Bay known as the Critical Area, activities are subject to natural
resource protection standards and restrictions, which require
the implementation of storm water runoff control devices and
other impact reviews and controls. Storm water and sediment
controls will be implemented to meet the requirements of this
regulation.
Applicable
-J
Applicable
Ground
Water
Action
Changes in Stream
Channels or
Floodplains
COMAR 26.04.07
Permits are not required for CERCLA actions. However, the
substantive requirements of the regulation must be followed;
therefore, this regulation is applicable.
Applicable
Ground
Water
Action
Maryland
Standards for
Groundwater
Monitoring and
Protection
DMAR
26.13.05.06
Applies to owners and operators of permitted hazardous waste
facilities, including landfills, for groundwater monitoring and
protection. This regulation addresses general groundwater
monitoring requirements, concentration limits, and compliance
points. The Dump is not a permitted facility; however, the
monitoring requirements are relevant and appropriate to the
situation at the site. A groundwater monitoring system will be
implemented to determine if migration is occurring from the
landfill.
Relevant
And
Appropriate
18
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Media
Ground
Water and
Soil
Ground
Water and
Soil
Ground
Water and
Soil
Hazardous
Waste
Soil
Air
Ground
Water and
Soil
Require
ment
Action
Action
Action
Action
Action
Action
Action
Table 2 Description of ARARs for Selected Remedy cont.
Synopsis of
Requirement
U.S. Army Corps of
Engineers(33OSC
1341 Certification]
33 CFR Part 323
Nontidal Wetlands
COMAR 26.23.01-
.05
Clean Water Act
Section 404
National Wide
Permits
Munitions Rule 40
CFR 264.300
Maryland Erosion
and Sediment
Control COMAR
26.09.01
Maryland Air
Quality Regulations
COMAR 26. 11.01-
26.11.02.21
Maryland
Regulations for
Well Drillers
COMAR 26.05
Action to be Taken to Attain Requirement
Although a permit is not required because this is a CERCLA
site, the substantive requirement must be followed. Capping
procedures must follow requirements for wetland protection
or implement engineering controls to minimize or prevent
adverse impacts.
Although a permit is not required because this is a CERCLA
site, the substantive requirement must be followed. State
policy on the destruction of wetlands requires that emergent
wetlands must be mitigated on a 1:1 basis.
Permits are not required for CERCLA actions. However, the
substantive requirements of the regulation must be followed.
After a munition is determined to be a solid waste, the
regulations establish if it is also a hazardous waste. White
phosphorous was found in a munition in the Dump. White
phosphorous is considered a RCRA hazardous waste because
it is highly reactive.
Requires a erosion and sediment control plan to be in place
for any federal project unless the project involves less than
100 cubic yards of grading of 5.000 square feet of grading.
An erosion and sediment and control plan will be
implemented.
Dust Suppression techniques will be used to minimize the
airborne transport of contaminated dust in compliance with
this regulation.
Applicable to the abandonment of monitoring wells within
the limits of the cap.
Status
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
19
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Table 2 Description of ARARs for Selected Remedy cont.
Media
Require
ment
Synopsis of
Requirement
Action to be Taken to Attain Requirement
Status
Ground
Water
Action
Groundwater Quality
Regulations COMAR
26.08.02.09
The Dump is not a permitted disposal unit; potential
discharges are being mitigated, and approval from the state
will not be needed or required. However, the purpose of the
regulation is to protect groundwater and surface waters of
the state: therefore, putting a soil cap on the Dump prevents
migration of contaminants to surface water and complies
with the substantive requirements of the regulation.
Relevant and
Appropriate
Hazardous
Waste
Action
AR 200-2
Environmental
Effects of Army
Actions
Provides guidance on incorporating into the CERCLA
process (FSs). It implements the Council on Environmental
Quality's NEPA regulations. As a matter of policy, the
organization preparing the FS ensures the document
complies with 40 CFR 1500-1508.
Applicable
Hazardous
Waste
Action
CEQNEPA
Regulations
40 CFR 1500-1508
This regulation will be complied with by implementing AR
200-2.
Relevant and
Appropriate J
—•
Applicable
Hazardous
Waste
Location
Fish and Wildlife
Coordination Act (50
CFR Part 402
Interagency
Cooperation-
Endangered Species
Act of 1973, as
amended)
No Bald Eagle nests are currently within 500 meters of
Cluster 3; applicable if there are possible impacts to
threatened or endangered species.
Hazardous
Waste
Location
Federal Conservation
of Wildlife Resources
50 CFR Part 402
(Endangered Species
Act)
No endangered species are believed to be within 500 meters
of Cluster 3. Applicable if there are possible impacts to
threatened or endangered species.
Applicable
Hazardous
Waste
Location
Maryland Threatened
and Endangered
Species Regulations
COMAR 08.03.08
The Bald Eagle is believed to forage in and around the study
area. However, no nest sites are currently within 500 meters
of Cluster 3. Construction activities are not anticipated to
impact the bald eagle: applicable if there are possible
impacts to threatened or endangered species.
Applicable
20
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3.0 RESPONSIVENESS SUMMARY
The final component of the Record of Decision is the Responsiveness Summary. The purpose of the
*
During the public comment period, written comments were received by APG.
APG held a public meeting on August 18, 1998, to formally present the Proposed Plan and to answer
STSS Alr/ndVpAT1115- The;ranfript °f ^ meetmg * part °f the ^ministnuive record S The
s te. The Army and EPA have conSldered all comments and concerns summarized below in selectine the
cleanup method for the Old Bush River Road Dump Site. selecting the
This responsiveness summary is divided into the following sections:
3.1 Overview.
3.2 Background on community involvement.
3.3 Summary of comments received during the public comment period and APG's responses
3.4 Sample newspaper notice announcing the public comment period and the public meeting!
3.1 OVERVIEW
™ , preferred altemative for ** ™ Bush
River Road Dump Site. APG proposed a soil cap and long-term monitoring. EPA concurred that the soil
cap would provide adequate protection for this site. EPA also indicated they would need to work wUh the
generally SUpP°rted the *™S* P^-S aZative £
C°mmentS- MDE has con'urred w«h the selected
dA C°ncems have been exPressed «*«« the type of
3.2 BACKGROUND ON COMMUNITY INVOLVEMENT
Focused Feasibili^ Smdy being scaned for ,he OU Bush
21
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The Board further discussed the site at the December 1996 and August 1997 meetings. In
August 1998, APG repeated the Proposed Plan briefing given at the public meeting on August
18 at the Board meeting.
• APG released the Proposed Plan for the Old Bush River Road Dump Site for public comment
on July 31, 1998. Copies were available to the public at APG's information repositories at the
Aberdeen and Edgewood Branches of Harford County Library, and Miller Library at
Washington College. A copy of the Proposed Plan also was posted on the Installation
Restoration Program's Web Site, and the public was invited to comment through the Web Site.
• APG prepared a release for the APG News announcing the availability of the Proposed Plan,
the dates of the public comment period, and the date and time of the public meeting.
• A 45-day public comment period on the Proposed Plan ran from July 31 to September 14, 1998.
• APG placed newspaper advertisements announcing the public comment period and public
meeting in The Aegis, the Cecil Whig, The Avenue, the Essex Times, and the Kent County
News.
• APG prepared and published a fact sheet on the Proposed Plan. APG mailed copies of this fact
sheet to over 2,650 citizens and elected officials on its Installation Restoration Program mailing
list. The fact sheet included a form which citizens could use to send APG their comments.
• On August 18, 1998, APG held a public meeting at the Edgewood Senior Center, Edgewood,
Maryland. Representatives of the Army, EPA. and the MDE presented information on the site
and their respective positions on the proposed cleanup alternatives.
33 SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD
AND AGENCY RESPONSES
Comments raised during the Old Bush River Road Dump Site public comment period on the Feasibility
Study and the Proposed Plan are summarized below. The comments are categorized by source.
COMMENTS FROM QUESTIONNAIRE INCLUDED WITH FACT SHEET
As part of its fact sheet on the Proposed Plan, APG included a questionnaire that residents could return with
their comments. APG received 10 completed returns. The alternatives preferred by individuals returning
comment forms were:
0 Alternative No. 1 - Take No Action.
1 Alternative No. 2 - Composite Cap.
6 Alternative No. 3 - Soil Cap (see comments I and 2 below).
I Alternative No. 4 - Vegetative Barrier Cap (see comment 3 below).
2 Have no preference.
22
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Written comments included on the form are summarized below.
Comment No. 1: "An excellent, thorough report."
Response No. 1: APG acknowledges and appreciates the feedback.
Comment No. 2: "If No. 3 does not comply with landfill regulations, then take alternative No. I."
Response No. 2: The selected alternative complies with all State ARARs. See comments from Maryland
Department of the Environment at the end of this Responsiveness Summary.
Comment No. 3: "If I understood correctly. No. 3 would require removal of trees and woody vegetation,
same as No. 2. I therefore chose #4."
Response No. 3: All of the alternatives would require the removal of some vegetation. Alternative 4, the
vegetative barrier cap, would be used in conjunction with a soil barrier cap and thus vegetation would need
to be removed. The purpose of the vegetative barrier cap would be to further reduce infiltration into the site
through transpiration. However, this is a new technology and may take longer to become effective as
compared to the other technologies. Therefore, APG and EPA selected Alternative No. 3.
COMMENTS FROM RESTORATION ADVISORY BOARD MEMBERS
As part of its efforts to involve the public in decisions as early as possible, APG provided Restoration
Advisory Board members with a draft of the Proposed Plan and a final version of the Proposed Plan.
Preferred alternatives and comments from Board members are summarized below.
0 Alternative No. 1 - Take No. Action.
1 Alternative No. 2 - Composite Cap.
4 Alternative No. 3 - Soil Cap.
0 Alternative No. 4 - Vegetative Barrier Cap.
1 Alternative No. 3/Altemative No. 4 (see comment no. 5 below)
Comment No. 4: "My only concern is that when work begins on the cap, dust and any other sources of
potential transmission of existing surface contaminants be kept to a level which is safe. Safe because the
work will occur in close proximity to family housing."
Response No. 4: APG agrees with this comment and will take appropriate dust control and sediment and
erosion control measures during the construction.
Comment No. 5: "Report does not state why Alternative 3 (soil cap) was chosen. According to the report,
the vegetative cap has many advantages with the only disadvantage being limit of contractor and amount of
maintenance. You might want to explain APG and MDE's reason for choice."
Response No. 5: The vegetative cap is also lacking in performance data for both short-term and long-term
implementation. For this reason, APG and EPA selected the soil cap. The soil cap is easier to implement
and maintain, will be protective of human health and the envi ronment. and is cost effective.
23
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Comment No. 6: "This alternative [alternative no. 3] seems to be the most cost-effective option."
Response No. 6: APG agrees that Alternative 3 is a cost-effective option. While protection of human
health and the environment is the most important criteria, the effective use of taxpayers' resources is a
criteria APG is required to consider.
Comment No. 7: "Since the true components of the landfill cannot be determined, there is at least one
exceedence, and the groundwater (water-bearing zone is hydraulically connected to the headwaters of
Lauderick Creek, I recommend the composite cap to ensure future leaching into the groundwater does not
occur. The added cost of $400,000 for the low-permeable cap is money well spent if it keeps metals from
entering the Bay. As the report admits, dealing with unknowns of the landfill, the plan should take a more
conservative approach."
Response No. 7: APG agrees protection of the Bay and other surface water bodies is important. Our
environmental sampling downgradient of the site found little evidence of contamination, except from the
erosion of the existing landfill surface soil. The proposed soil cap will prevent further erosion and mitigate
the possibility of movement of metals in the Bay. In addition. APG will implement a long-term monitoring
program that includes sampling and bioassays to ensure the soil cover is functioning properly and continues
to be protective.
COMMENTS AT THE AUGUST 18.1998 PUBLIC MEETING
A full transcript of the public meeting is at APG's information repositories. Following is a summary of
verbal comments made at the meeting. (Several comments made by a consultant to APGSCC at the public
meeting are addressed in the section which includes all of APGSCC's comments.)
Comment No. 8: A representative from Harford County Division of Environmental Affairs asked why a
single membrane cap or similar design was not considered. He also asked about the potential for lateral
movement of substances from buried munitions along the interface between the soil cap and the underlying
clay layer.
Response No. 8: In response to the first comment, the State of Maryland regulations require a double-layer
cap for hazardous waste landfills. The State of Maryland has determined that the requirement for a double
layer cap does not apply to the Dump. Several capping configurations were evaluated in the FS. The
selected alternative meets or exceeds the requirements identified by the State.
In response to the second comment, APG did evaluate the potential for munitions to be in the landfill and to
detonate. APG believes it is possible for munitions to be present but very unlikely that they would detonate.
APG believes Alternative 3 will provide adequate protection of human health and the environment even in
the unlikely event a munition would detonate.
OTHER WRITTEN PUBLIC COMMENTS
The following written comments were submitted from a resident:
Comment No. 9 : "It appears that Alternative 3 is the most cost-effect, proactive remedial measure. I am
not clear, however, as to the material to be used for the 3-foot foundation. Would this be an impermeable
24
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material? Would this material be calcium based or enriched due to the migration of metals observed at the
site leaching into ground water?
Response No. 9 : The exact specifications of the cover will be contained in the remedial design which is
the next step in the process. Once the design is complete. APG will send the community a fact sheet
showing the exact specifications of the cover. It is anticipated the three-foot foundation will be a common
borrow soil, and would not be impermeable. It is not expected that the material would be calcium enriched.
A second layer of topsoil, with a minimum of !/2 foot thickness, will be placed on top of the foundation
layer. This layer will include a vegetative cover which will reduce infiltration of precipitation into the
landfill by 76%.
Comment No. 10: The commenter noted Alternative 1 was not acceptable. He stated Alternatives 2 and 3
are the most reliable remedial approaches, with Alternative 2 being the most conservative and costing over
$400,000 more to implement. He asked: "How many monitoring events would be required with each
alternative to determine effectiveness and obtain closure? Will the State issue a waiver to COMAR
26.13.14 to avoid a possible NOV? Should the State stand firm with COMAR, it would be worth spending
the extra $400,000. Although I believe that if the cost estimations are accurate and the general effectiveness
of Alternative 3 is sufficient that the State will essentially be forcing the installation to waste federal tax
dollars based on formalities and technicalities."
Response No. 10: See comments from the Maryland Department of the Environment at the end of this
Responsiveness Summary.
Comment No. 11: "I do not understand why the Risk Assessment was overly conservative and included
ingestion as an exposure pathway. If this aquifer of concern was determined not to be viable, then why
would any other scenario outside of the "construction worker scenario" be applicable? Was ingestion
included due to the proximity of the Bush River? Is there evidence that the aquifer provides base flow to the
river (a good assumption). At that point, would you be considering the source of ingestion to be through
fish and game that would use the river as a drinking water source? Or are there municipal water intakes
located downstream? Thank you for this opportunity to comment."
Response No. 11: APG follows EPA guidance in preparing Risk Assessments; this guidance is very
conservative to be protective of the public and the ecology. Under the guidance, APG looked at potential
exposure pathways including ingestion by humans. The ecological risk assessment examined the potential
for impact to fish and other aquatic life. The ecological risk assessment found only a limited potential for
any adverse effects. APG's surface water sampling also showed only one minimally elevated detection of
dissolved lead above the Federal Ambient Water Quality Criteria.
COMMENTS FROM APG SUPERFUND CITIZENS COALITION f APGSCO
APGSCC is the recipient of Technical Assistance Grants from the U.S. Environmental Protection Agency.
These grants allow APGSCC to hire consultants to help them review and comment on technical documents.
Following are comments prepared by APGSCC and their consultant, the University of Maryland.
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Comment No. 12: "Presenting only no action and capping alternatives for this 1.56-acre site reduces the
community's ability to evaluate a reasonable spectrum of possible solutions and to concur or disagree
with the selected approach. As raised by APGSCC's technical consultant at the Restoration Advisory
Board meeting, an appropriate diversity of alternatives should be included in the proposed plan. While
the selection of these alternatives was based on EPA's presumptive remedy for municipal and military
landfills, it should be noted that the Citizen's Guide to Understanding Presumptive Remedies supports the
community's right to request the evaluation of other alternatives."
Response No. 12: EPA's objective for presumptive remedies is to use past experience at similar sites to
streamline investigations and speed up selection of cleanup actions. The use of presumptive remedies can
ensure consistency in remedy selection and reduce the cost and time required to clean up similar types of
sites. EPA expects presumptive remedies to be used at all appropriate sites except where site-specific
circumstances suggest that either the presumptive remedy would not be appropriate, or that another
remedial alternative would be clearly superior when evaluated using CERCLA remedy evaluation criteria.
As discussed in the feasibility study, EPA established source containment as the presumptive remedy for
CERCLA municipal landfill sites in 1993, and in 1996 issued guidance on the application of this
presumptive remedy to military landfills. The guidance presents a decision framework to use in
determining if use of the presumptive remedy is appropriate. This decision framework is presented and
employed in the feasibility study, and clearly indicates that the presumptive remedy, containment, is the
most appropriate remedial response.
Published policy and procedures by EPA on presumptive remedies states: "The identification of a
presumptive remedy does not relieve the EPA or the Army of the obligation to respond to comments
suggesting that other alternatives should have been considered." The guidance further states: "... the
submission of comments advocating other approaches does not necessarily require broadening of the FS
or EE/CA, or conducting additional analysis after the plan has been proposed. Whether additional
documentation is required will depend upon how substantial or persuasive the comments are (e.g.,
whether a comment identifies unusual site circumstances that seriously call into question the applicability
of the presumptive remedy)." APGSCC has not identified any such site circumstances that would make
the presumptive remedy inappropriate, and other alternatives do not warrant more detailed study.
Comment No. 13: "The ERP's determination that excavation is not feasible due to costs and explosive
risks, as delineated at the RAB, are not conclusions that should be drawn before public comment and full
discussion of the pros and cons via the RAB and the proposed plan. The presence of munition wastes has
been raised as reasoning for why excavation is not a possibility. However, as APG has vigorously
pointed out at other sites, no chemical warfare materiel (CWM) has actually been found at Cluster 3, and
one should not automatically assume that it is present just because an empty CWM round was retrieved.
Additionally, contamination has migrated from the site, as elevated contaminants have been found in
Lauderick Creek. The information does not appear to definitively indicate that capping the site will
improve the quality of Lauderick Creek. This site contains a push out area resulting from the clearance of
past burning and dumping activities, by which wastes are pushed out into the marsh to allow additional
disposal activity. At a minimum, monitoring will need to take place in the marsh and creek to evaluate
the effectiveness of the proposed alternative. Ecological impacts in Lauderick Creek from current
contamination levels should also be adequately evaluated. Without comprehensive exploration of
unknown site characteristics, APG runs the risk of exposing unsuspecting individuals to unnecessary
risks, and although this is not always avoidable, the seriousness of inadequate source evaluation and
environmental fate must be given considerable weight in selecting a course of action."
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Response No. 13: EPA guidance requires issues related to m.litary-speciflc wastes be considered in the
feasibility study, and that an evaluation be performed to determine if excavation of the waste is practical
This analysis is a fundamental element in determining the applicability of the presumptive remedy at the
OBRRD and was accomplished during the feasibility study. During the public comment period the
public is encouraged to review the feasibility study. Also, members of the public may form their own
opinions, suggest other alternatives, and provide feedback to the Army and EPA The use of the
presumptive remedy approach was presented at the August 1997 RAB meeting thus informing RAB
members early in the process of the planned approach.
For the OBRRD, both an empty Livens projectile (the empty CWM round) and an explosively configured
white phosphorus munition {4.2 inch) have been found at the site. While no rounds containing lethal
chemical warfare materiel (i.e., mustard, phosgene, Lewisite, etc.) have been found, given the time period
of sue usage, the existence of such items at the site is possible. Munitions filled with CWM have been
recovered in the Bush River Area. It also should be noted that the presence of ordnance containing
explosives and white phosphorus are also a significant hazard, would make site excavation a hazardous
operation.
Surface soil within the OBRRD contains lead and other constituents of concern. Without remedial action
erosion processes would result in continued release of these constituents to Lauderick Creek The soil
cover will prevent transport of constituents of concern to Lauderick Creek and also will achieve all other
remedml action objectives. The effectiveness of this remedy in protecting human health and the
environment is clearly stated in both the feasibility study and the proposed plan.
Monitoring of nearby Lauderick Creek sediments is planned. The work will include chemistry and
thereafter quartedy samPlin8 evfints from before and after construction, with annual monitoring
Comment No. 14: "The TAG Group strongly suggests that all future proposed plans be expanded to
present more diverse alternatives to be considered. Excavation and partial excavation scenarios should be
fully evaluated within the feasibility study and outlined within the proposed plan. Simply stated the
community cannot participate if only limited options are included in the document that is most likely to
be read by the public." J
Response No. 14: Consistent with EPA guidance and policy, APG will continue to consider presumptive
remedies where appropriate. The consideration of presumptive remedies can both accelerate remedial
programs as well as reduce costs, thus benefiting the public. Use of presumptive remedies does not limit
community participation, and expansion of the feasibility study process to perform detailed analysis of
remedial alternates that are not practical does not expand public participation and is not an effective use
or taxpayer resources.
APG intends to consider the use of presumptive remedies for the 22nd and 30th Street landfills in the
Southern Bush River Study Area, as well as other similar sites. The decision to limit feasibility study
work to consideration of only no action and the presumptive remedy, or to have an expanded feasibility
study with consideration of a wider range of alternatives, will be made during the feasibility study
woT* hr°Ce,SS ™* P«fcil»Mon by APG, EPA Region III, MDE and the public. The feasibility study
work at these landfill sites has been initiated and scoping will occur during calendar year 1999
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Comment No. 15: "APGSCC has long supported the characterization of contamination from a holistic
perspective." "As for the risk assessment, the contamination and resulting risks at a particular site should
be evaluated in conjunction with other risks from nearby contamination. Assessing the Cluster 3
contamination as it relates to adjacent sites should be done."
Response No. 15: APG agrees that that it is important to consider data from nearby study areas when
evaluating contaminant transport and when assessing risk. Both a regional and local perspective must be
maintained when developing an understanding of groundwater movement. A substantial amount of
investigation has been accomplished in the Cluster 13 area, and data collection to support the Cluster 13
feasibility study work is ongoing. The groundwater plume from Cluster 13 does extend southward across
the local branch of Lauderick Creek, but is still roughly 2000 feet from and has no potential to impact
groundwater quality in the Cluster 3 and the OBRRD area. There is no use of groundwater from the
Cluster 3, Cluster 13, or onpost housing areas, and because there is no exposure pathway, there is no risk
to current APG workers or residents from Cluster 13 groundwater. Alternatives for remediation of
groundwater in the Cluster 13 area are being analyzed as part of ongoing feasibility study work for that
operable unit, and that work has no relationship to the OBRRD remedial decision process. Data from
both efforts is being considered when developing an understanding of groundwater occurrence and
movement in the general vicinity of Lauderick Creek.
APG agrees, when assessing risk to ecological receptors within a drainage basin, it is appropriate to
consider all of the contaminated areas within the basin, and that there are potentially additive impacts of
separate sources and contaminated areas. APG has been conducting ecological risk assessment work
addressing large geographical areas, with the studies of the Gunpowder and Bush Rivers and their
tributary creeks being examples. As monitoring and assessment work in Lauderick Creek proceeds, all
data will be evaluated when assessing risk.
Data from adjacent contaminated sites has no bearing on the conclusions of the RI/FS that soil within the
OBRRD contains constituents at levels that create risk to potential ecological receptors, that constituents
have migrated to nearby Lauderick Creek sediments via erosion and sediment transport, and that
remediation of the OBRRD as a source is necessary. Data from studies in adjacent sites is not necessary
for remedial alternative selection for the OBRRD.
Comment No. 16: "The Transformer Storage Area within Cluster 3 is the other area of concern within
Cluster 3 that was evaluated within the remedial investigation. The authors of the report concluded that
no further action was necessary at this site. Yet, within the proposed plan, it is stated that this site is
recommended for further evaluation. Chapter 6 of the remedial investigation mentions determined
concentrations of metals and DDT (and degradation products) present within the cluster, and evaluated
potential impacts to terrestrial plants, soil-dwelling invertebrates, small carnivorous mammals and
carnivorous birds. The risk assessment supported the possibility of impacts as a result of the metals and
pesticides measured, including arsenic, cadmium, mercury, nickel, lead and selenium. APG should
clarify whether additional evaluation will be considered. Based on the risk assessment, additional
investigation, including bioassays, seem appropriate. Sampling areas of clear concern include soil sample
locations SS-04 and SS-05, where some of the highest metal concentrations were detected. SS-04 exists
within the heart of Transformer Storage Area (Site 23) and SS-05 appears to be outside the landfill area to
be capped. Please clarify if these areas of soil contamination were addressed during any removal action
to date. If they are not, what efforts will be made to ensure that continued run-off and wind dispersion
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does not add to the already elevated concentrations of some of these metals in the sediments of Lauderick
Creek. Considering that this area may remain a source area, will there be any assessment of the soil
between these two sampling locations to determine the extent of these particularly high areas? APGSCC
requests that the community be updated on the further evaluation that is to take place according to the
proposed plan as the TAG Group cannot support no further action as recommended in the if media!
investigation
Response No. 16: Supplemental surface soil sampling is planned for the Site 23 area, within which the
former transformer storage area was located. The objective of the supplemental surface soil sampling and
analysis is to determine the extent of lead in surface soil at locations SS-04 and SS-05 in support of a
planned removal action to address soil containing lead at greater than 200 mg/kg. Samples at SS-04 and
SS-05 w,ll also be analyzed for PCBs. Data from this supplemental soil sampling and Analysis, together
with data from the planned sediment monitoring and bioassay and that data already available will provide
Site ?f and ^SSS^n0^11 C0"taminat!on and contaminated sediment transport in the vicinity of
under evaluation additional work to address other constituents in soil is currently
T" ^"u118 T e" accomPlished at Site 23-' The exact extent of the soil cover for the
anet
andi, HH ' bUt k JS antic'Pated that le*d ™ surface soil at both
and SS-04 will be addressed by a removal action to be accomplished after the planned sampling
ne the lXtent °f lead" APGSCC the Resto^,on Advisory Board, and the public
f°r the °BRRD s°" c-er -d ^ - -*•£-
Comment No. 17: "With regard to Site 23, it should be mentioned that a removal action was conducted
lkl7rn°rreTVf * C°nCrete ^ ^ * "* 8ite °f f°fmer Buildin* E1372> « underground storage
ank and contents of a sump assoc.ated with this building. From the remedial investigation it appears that
conCCp°fT f In S3mpl£g C°nfirmed that contaminated Aerials had been removed SSwTto a
concentrauon of 50 ppm. The remedial investigation indicates that the 50 ppm clean up level is a
regulatory / guideline for determining sites with contamination that would require management as TCB
waste and/or hazardous waste. However, this the clean up conducted through this removal action does
not appear necessanly to be protective of human health or the environment The industrial ristbued
^ «* — - -"a is 100 pp,
Response No. 17: The objective of the removal action was to remove contaminated structural materials
and terns requmng management as PCB and/or hazardous waste (concentrations exceeding 50 ppm)
s o1thCeTmWaS» n? implemented to remove a11 -' ^at might have been contaminated^ The
s ot the removal action were accomplished.
rasess ?*!'** ^ ™K "* ^ '" ^uantitative risk assessment calculations
«mnr T g *f J , Cr remediatlon at the ^moval action site. The supplemental soil
sampling discussed above will include analysis of selected samples for PCBs.
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Comment No. 18: "Significant issues remain to be addressed regarding the RAD risk assessment
conducted at Cluster 3. While RESRAD was used as a screening method, the support documents contain
almost no information regarding the parameters used in the modeling. One section of the RI indicates that
this model may have only been used to assess soil contamination. Attachment B to the risk assessment
portion of the RI Report notes that the ingestion of drinking water was not considered in the RESRAD
model, which brings into question the validity of the future scenario risk assessment. Were inhalation and
ingestion considered in the RESRAD modeling?"
Response No. 18: During the last several years, the approach to human health risk assessment for
radionuclides has evolved. The current approach at APG is consistent with the approach employed at
most other facilities, including Department of Energy facilities.
The approach involves calculating risk using two methodologies. The first methodology is to simply
calculate carcinogenic risk using cancer slope factors in a manner identical to that for carcinogenic
chemicals, with the risk result then being compared to the EPA target range of 10"6 to 10"4 for excess
lifetime cancer risk. The second methodology involves the calculation of radiation dose which is then
compared to a health-based criteria, with 1-5 millrem/yr (mrem) currently proposed by EPA. The 15
mrem/yr effective dose equivalent is approximately equal to a cancer risk of 3 x 10"4. The identification
of radiological constituents of potential concern for inclusion in the quantitative risk assessment is
accomplished by screening against risk-based activities (RBAs) in a manner identical to screening of
chemicals against risk-based concentrations (RBCs). The RBAs are calculated using exposure
assumptions and procedures identical to those used for calculating RBCs (with modifications that are
appropriate for radiation/radionuclides).
The approach to risk assessment for radionuclides is conceptually identical to that for chemical risk
assessment. There are necessarily some differences in details. For example, radiological risk assessments
must consider the effects of external gamma radiation, as well as exposure routes such as ingestion and
inhalation.
The risk assessment for Cluster 3 was originally accomplished approximately two years ago, using an
approach that, at that time, was considered by regulatory authorities to be acceptable for APG sites.
When the Cluster 3 RI report was finalized in August of 1998. the original radiological risk assessment
was used, but at the same time a reassessment was accomplished using the currently accepted
methodology discussed in the above paragraph. RESRAD is simply a computer program that can be used
as a tool to calculate dose estimates given radionuclide concentrations in environmental media and
exposure assumptions.
The RESRAD model calculations for the reassessment included estimates of risk from ingestion of
soil/sediment, ingestion of groundwater and external radiation. Soil was the only source term used in the
RESRAD calculations, and groundwater exposure was based on RESRAD estimates of transfer between
media rather than actual groundwater data. Inhalation was not included as an exposure route because it is
not significant for the Cluster 3 site. For Cluster 3, nearly all of the estimated risk is from external
radiation because Cs-137 and K-40 are strong gamma emitters. Default input parameters for RESRAD
were used in the Cluster 3 risk assessment, and assume a subsistence farming land use scenario. This
scenario is conservative because it allows for a relatively high level of exposure to soil and the crops
grown in it.
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In discussing radiological risk assessment, it is also important to understand that the data used in the
radiological nsk assessment is from gamma spectrometry analysis. Gamma spectrometry is a very useful
screening toot for .dentifying radionuclides that may be present and the approximate level of activity
within a media sample. However, it must be recognized that not all gamma spectrometry data are of
sufficient precision and accuracy for use in a quantitative risk assessment, and are appropriate only for
initial screening level site assessment and estimates of risk. Gamma spectrometry data often have a high
relative level of uncertainty at low concentrations near the detection limits, which is often the situation
when analyzing environmental samples, and is the case for the Cluster 3 samples. The interpretation of
gamma spectrometry data must include evaluation of the estimated concentration relative to the detection
Iimit^ the total propagated uncertainty relative to the estimated concentration, and the potential for
interference. ^
The precision and accuracy of gamma spectroscopy data are dependent on a number of factors including
the radionuchde of interest. Gamma spectrometry is generally a relatively good method for identifying
and quantifying the concentrations of strong gamma emitters in a sample. For example, gamma
spectroscopy provides relatively good data for Cs-137. The detection efficiency for other radionuclides
relative to Cs-137 can vary substantially, with a factor of 20 not being unusual. This variation in
detection efficiencies is greater than for gross alpha and gross beta analyses, where relative detection
efficiency factors are more typically in the 3 to 4 range.
The results of gamma spectrometry analysis are subject to interference because different radionuclides
can have emissions at the same energies. For example, both radium-226 and uranium-235 are naturally
occurring and have an emission energy of 186 Kev as part of their characteristic emission spectrum U-
235 also has emissions at higher energy levels and in interpretation of the data a computer estimates the
relative amounts of Ra-226 and U-235, but not always with a high degree of accuracy. The combination
of this interference and uncertainty in analysis are the reasons why it is not uncommon for gamma
spectrometry to show Ra-226 levels that are inconsistent with and much higher than the gross alpha
measurement. In such an instance the gross alpha should be used to assess the maximum levels of Ra-226
that could be present m the sample. When there is inconsistency between gross alpha data and Ra-226
data from gamma spectrometry analysis, radium analysis should be accomplished using more suitable
methodology.
method °f a"alySiS dePends on both the radionuclide of interest and also the media of concern
For Ra-226 in water, radon emanation is the methodology that is appropriate for drinking water sample
analysis, and for generation of data for use in quantitative risk assessment where radionuclides are of
concern. The measurement of activity by alpha emitters in water is most commonly accomplished by
alpha spectrometry. Because of the nature of alpha and beta radiation, gamma spectrometry is the most
commonly employed method for soil analysis. In recent years the approach to radiochemistry analysis for
some study areas has been to perform gross alpha, gross nonvolatile beta and gamma spectrometry
analyses on all samples. The routine use of gamma spectrometry for all samples at APG is being
discontinued and gross alpha and gross nonvolatile beta will be used as screening tools. For water
samples, further analyses will follow the approach used for drinking water sample analysis. For soil
samples, further analysis will be accomplished when there is evidence of radionuclide contamination at a
site. This is the commonly used approach at CERCLA sites, including at DOE facilities
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The Cluster 3 remedial investigation and risk assessment were accomplished using the best available data,
which for radionuclides is entirely from gamma spectrometry analysis. The radiological portion of the
human health risk assessment has been revised using the latest accepted procedures. This revised risk
assessment determined that Cluster 3 risks associated with radionuclides are not substantially different
from risks associated with local background concentrations.
When considering radionuclides in the environment, it must also be remembered that many are naturally
occurring, and that certain others are man-made and found in environmental media as a result of historical
nuclear weapons testing. For example, potassium-40 (K-40), Ra-226 and thorium-228 (Th-228) are
naturally occurring, and cesium-137 is a man-made radionuclide that is commonly found in
environmental media as a result of fallout from weapons testing during the 1940s and 1950s.
K-40 is of relatively high abundance (0.0117%) and long half-life (1.28 billion years). Because
potassium is a very abundant element in nature, it is common for a substantial portion of nonvolatile gross
beta activity in samples to be due to naturally occurring K-40. K-40 is also a gamma emitter, and the
greater abundance of potassium in clay minerals than in silica sands is the reason why natural gamma logs
of boreholes can readily identify zones of high clay that will act as low permeability confining units and
distinguish them from sandy aquifer zones. K-40 is also commonly found in solution in surface water
and groundwater, and is often the principal source of nonvolatile gross beta in groundwater samples.
Unfiltered groundwater samples will often have very high levels of nonvolatile gross beta activity when
they contain suspended silt and clay particles, because those particles contain potassium.
Comment No. 19: "The proposed plan states that there is no historical documentation of what was
disposed of at the site. However, the community was recently informed that Chemical, Biological
Defense Command (CBDCOM) has a 4-story vault containing historical records of their activities. These
records need to be evaluated as soon as possible. While DSHE may not be able to investigate this
information source prior to the Record of Decision for this cluster, every effort should be made to do so
before the remedial work at this site begins."
Response No. 19: The 4-story vault referred to is a part of the CBDCOM Technical Library system. The
classified card catalog for this library was thoroughly reviewed as an element of the RCRA Facility
Assessment for the Edgewood Area of APG. Thousands of documents in this library were reviewed for
information related to waste management. Environmental studies and reports were not prepared during
the period prior to World War n, and the logbooks and technical reports of the library only make
occasional reference to methods of waste disposal, and most often do not mention the exact location of
disposal activities. None of the library documents reviewed describe the OBRRD or the nature of wastes
disposed at that site. While it cannot be stated with certainty that there are no documents within the
library containing such information, the review work already accomplished suggests that a 100% review
of library documents would provide little if any information related to the OBRRD. It is unlikely that
information from historical documents would change the conclusions of the remedial investigation and
feasibility study, and would not change the conclusion that the presumptive remedy, containment, is the
most reasonable remedial approach.
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Comment No. 20: 'The groundwater flow and contamination migration issues appear complicated in the
Cluster 3 area, and our TAG review of the available information has raised multiple concerns Included
m these observations is the potential that the identity of the different aquifers may have been
misinterpreted. Furthermore, the presence and migration of certain classes of contaminants need to be
meticulously reviewed, as APG's ability to assess present and. more importantly, future exposure
pathways depends on the comprehensive evaluation of known contamination, environmental fate and
potential sources. This request to review such issues is supported by the determination that the non-
cancer health nsks to a future worker, via groundwater. exceeds the hazard quotient of 1 which is not
discussed in the PP. APGSCC requests that APG and the EPA evaluate these concerns described below
to ensure that these important issues are being assessed adequately. A written assessment would be
appreciated, although a follow-up meeting may be necessary if the response does not clearly outline the
logic and supporting data for the conclusions drawn in these CERCLA documents."
Response No. 20: The issues related to groundwater occurrence and interpretation of aquifer zones is
complex at Cluster 3, and because of this complexity, a substantial effort was made to coordinate the
interpretation and remedial investigation description with geologists from both EPA Region m and the
MDEpnor to publication of the remedial investigation report. It is hoped that the following responses
(21 through 27) to specific comments will be informative and helpful. APG also is willing to hold a
follow-up meeting to help clarify issues.
Comment No. 21: 'The proposed plan indicates that because the groundwater has been classified as a
type m aquifer, water quality criteria were used in the evaluation process instead of maximum
contaminant levels (MCLs). However, the MCLs were used as the comparison criteria in chapter 4 of the
Remedial Investigation Report. It has been an ongoing practice at APG in recent years to select
chemicals of concern based on the EPA's risk-based concentrations (RBCs) from Region ffl, which were
used in the baseline risk assessment discussion in Chapter 6 of the remedial investigation Report What
was the reasoning for the alternating comparisons?"
Response No. 21: Different comparisons were made because in each of the circumstances the objectives
of interpretation and discussion were different. While the groundwater has been classified as a Type m
aquifer, it is still useful and necessary to discuss nature and extent of contamination in groundwater
Chapter 4 of the remedial investigation contains comparisons to Maximum Contaminant Levels (MCLs)
and to RBCs for tap water for constituents without MCLs. because these comparisons are useful tools in
discussion of nature and extent of contamination. In Chapter 6 of the remedial investigation the risk
assessment, constituents of potential concern are identified by screening against appropriate RBCs (or
KBAs tor radionuchdes). MCLs are not used in this screening to identify COPCs because MCLs while
based at least partly on health considerations, are not set ut a concentration that correlates to a specific
level of risk. Therefore, the RBCs for tap water are a more conservative and consistent screening tool for
risk assessment In the feasibility study and proposed plan, the objective was to illustrate that the
discharge of shallow groundwater to surface water was very unlikely to have any adverse impact on
surface water, therefore the Federal Ambient Water Quality Criteria (FAWQC) were used as appropriate
comparison criteria. Please see the responses to following comments for related discussion
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Comment No. 22: 'There appears to be significant disconnect between the nature and extent of
contamination discussed in Chapter 4 of the remedial investigation Report, the baseline risk assessment
discussed in Chapter 6, and the groundwater contamination referenced in the proposed plan. With regard
to organics. Chapter 4 discusses 1,1,2,2-tetrachloroethane and a variety of pesticides. However, the
baseline risk assessment included compounds such as benzene. benzo(a)pyrene, carbon tetrachloride and
chloroform as chemicals of potential concern (COPC), while many of the pesticides and 1,1,2,2-
tetrachloroethane were not assessed in the risk assessment. Also, certain inorganics were selected as
COPCs but not discussed in Chapter 4, including cobalt and vanadium. Complicating anyone's effort to
participate in this process even further is the fact that the proposed plan mentions cadmium as the only
chemical of concern identified by the risk assessment process, but this metal is not discussed in Chapter 4
or Chapter 6."
Response No. 22: The differences in discussion between Chapters 4 and 6 of the RI report are due to the
differences in the objectives of the discussion. Chapter 4 is a presentation of nature and extent of
contamination. Chapter 6 is an assessment of risk to human and ecological receptors.
The differences in constituent discussion is in part a function of the data screening process for the two
chapters, which has already been discussed in the response to comment no. 21. An example of how the
two data screening processes can result in focus on different sets of constituents can be illustrated by
considering benzene in groundwater. Benzene was detected in 1 of 11 surficial aquifer groundwater
samples at a concentration of 1.4 ug/L. This concentration is less than the MCL of 5 ug/L, and was not
the focus of discussion in Chapter 4 of the remedial investigation. However, the single detected
concentration does exceed the RBC for tap water, and was designated as a COPC in Chapter 6.
APG recognizes that this difference in data screening and presentation approaches can be confusing and
misleading. More recent remedial investigation reports now in preparation are using a slightly different
approach in Chapter 4 of the RI report. Tables for each environmental media at each waste unit/site/area
of interest will list all detected constituents, the frequency of detection, other summary statistics including
range of detected concentrations and mean concentration, and comparisons to (1) background
concentrations. (2) ARARS (MCLs for groundwater, etc.). and (3) risk-based screening levels for human
health and ecological receptors, as appropriate. This approach will present a wide range of information,
and better illustrate to readers the range of constituents that may be related to site historical activities,
those for which there may be some associated risk (human or ecological), and finally, those that exceed
ARARs. This approach will also be more consistent with and a better lead-in to fate and transport analysis
in Chapter 5 and the risk assessment in Chapter 6.
Comment No. 23: "With regard to groundwater, the geological cross sections (figures 3-5 through 3-7)
within the RI appear to have an area of discrepancy. Figure 3-6 presents a wide surficial aquifer
northwest of the landfill, stretching from 10 - 25 feet above mean sea level (MSL). In this cross section,
the surficial aquifer is shown to reduce in thickness and more downward to 0 MSL at WBR-06 and WBR-
04. These two data points are in close proximity to WBR-05. Figure 3-5, depicting the geology at WBR-
05, shows the canal creek aquifer to be present at 0 MSL. Please explain this observation in the data."
Response No. 23: The information in the report is correct and demonstrates the discontinuous nature of
the surficial aquifer within Cluster 3. What is portrayed in the cross sections is the best interpretation
based on lithology at the boring/well locations. This APG interpretation was reviewed and considered
reasonable by geologists of the Army Corps of Engineers, MDE and EPA Region DDL
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Comment No. £4: We need to assess what ramifications are possible from the hydraulic connect.on
shou>edenb lie?** -""IT1 -^ek aqUifefS WUh regUrd t0 long-tem ""tarnation migration It
should be noted that in the feasibihty study, the aquifer identified as the surficial aquifer is in close
proxirnuy to what is identified as the Canal Creek aqu.fer. It is not clear that this shallower aquifer is
separated from the lower water-bearing unit by a continuous confining layer. In fact the cross-lections
provided in the FS suggest that as one moves from the area which thetwo* streams converge a ^ the head
waters of Laudenck Creek back toward the marsh area to the west of the proposed cap area the two
aquifers come closer together. Why has APG contractors not developed a three-dimensional model of the
subsurface? If these aquifers are connected, the notion from APG reports that contamination in the Canal
Creek Aquifer originated from the west in the Canal Creek Study Area would be questionable."
Response No. 24: In the area immediately west of Cluster 3 the Canal Creek Aquifer is also the surf.cial
y ,'* K V°"e mOV6S eaf-tWard im° the CIuster3 area' the Canal Creek A^fer dips, becoming
eparated by Cretaceous confining clays from a surficial aquifer that is discontinuous in nature and very
'
n naure an very
file's? sThrnu'hTVTS' ?" ^™ ^ and ^ thr°Ugh 3'7 of remedial inv^tigation report and
r™?r I Se feasibility study report). The possible connection between the surficial and
Canal Creek aquifer zones m this area has been given much consideration, and the most definitive
evidence is from water level measurements that show a large difference in groundwater elevation between
he two aquifer zones throughout the Cluster 3 area. This large difference in groundwater elevadon
approximately 12 ft) indicates that there is no hydraulic connection between the Ca?al cJ^dfeS
the surficial aquifer (where it exists) in the Cluster 3 area.
The cross sections are a three-dimensional model depicting the interpretation of lithology within the area
No numencal groundwater flow model has been developed because groundwater is not a trans^rt
n^ ^JTT? 6m K?1 ^ °BRRD (°ther tha" Seepage of Perched water within the fill
matenal created by the lower permeability of the fill material relative to surrounding native soils which is
discussed in the feasibility study report).
Comment No 25: "While it is not discussed in the proposed plan/nickel is present in the Canal Creek
Aquifer at well WBR-03 located at the southern perimeter of the OBRRD. £ fact, nickel is present!*
his aquifer at concentrations above 2,000 ppb, which is more than 20 times the McL for this metal As
Hndf^ 1SHahWare' M COmp°Unds including U^-tetrachloroethane, alpha-BHC, gamma-BHC
oS± l^ P ^oxide were found in the Canal Creek Aquifer at this Nation. Data for various
S ? r in°LganiC C°mpOUnds sugSest that contamination in the vicinity of this well migrate toward
Laudenck Creek, as various contaminants were found at WBR-08 at the next highest concentrations
knn Trl Bd t*" ^"^ " ^^ °f 8°° PPb>' In U«ht °f thls' II WOUld ««™ importamto
s^Ll ab^BTAr5 ^rr fCharf S £° LaUdenCk Creek' Where nickel has ^ ^ ££
he S S A^v-, J . T ^ S, b,ee" Sh°Wn 3t °ther IOCati°ns induding KinSs Creek' acco^i"g '0
the U.S. Army s Ruk and Bwlogtcal Impact Assessment, where contaminants from the Canal Creek
Aquifer have been shown to be discharging to surface water bodies."
tafdaricTr ^ th%CanalfGrheek A^uifer diPs toward the southeast, it is likely that it does not
ok aufer the n r r ! I ? WM d'SCharge °f contaminated groundwater from the Canal
quaTitv of ^ ?dimenrP H ial,jmpaCtS W°uld not be "Assessed or ignored. Past efforts have assessed the
quality of sediment and surface water within Lauderick Creek, and as RI/FS efforts continue at sites
within the Lauderick Creek drainage basin, such assessments will continue.
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It is also suggested that caution be exercised in the use of contaminant concentrations to determine the
direction of groundwater flow. It cannot always be assumed that groundwater movement is from a well
location with high concentration toward one with lower concentration of a particular constituent. Site
hydrogeology will determine groundwater flow pathways, and dissolved constituents will move along
these pathways. Constituent concentrations can provide very valuable insight into groundwater
movement, but is secondary to hydrogeologic data in importance in assessing flow pathways.
Comment No. 26: "While there are multiple lines of evidence to suggest that contamination is flowing
from WBR-03 toward WBR-08, one must entertain the possibility that WBR-03 may be situated on a
divide and that groundwater also flows from this point toward the west (WBR-05) and the Canal Creek
Study Area. In fact, I believe IRP personnel at previous RAB meetings have presented information
regarding the migration of contamination from the Northern Bush River Study Area toward the Canal
Creek Study Area. The detection of the same pesticides and various metals in well WBR-05, as those
found at WBR-03, support such a possibility. This observation plus the fact that nickel turned up in other
wells believed to be in a different aquifer reinforces the need to resolve the observation discussed above -
namely that the IRP must be sure that the surficial and Canal Creek aquifers have not been misidentified
from one location to another. These concerns regarding aquifer identification and contaminant migration
direction is also supported by the radial flow contours depicted in figures 3-9 and 3-10 of the RI report."
Response No. 26: "Water level data over a period of time shows that groundwater movement in the
Canal Creek Aquifer is consistently in roughly an eastward direction across the Cluster 3 area.
Constituent concentration data cannot be used alone without hydrogeologic data in assessing groundwater
movement. Figures 3-9 and 3-10 of the remedial investigation report are for the surficial aquifer zone,
and not the Canal Creek Aquifer.
The presence of nickel in surficial aquifer groundwater at the locations of wells WBR-04, -06 and -07,
and in Canal Creek Aquifer wells WBR-05 and -03, suggests that there was a historical source of nickel
in Site 23, as stated in the remedial investigation report. A review of the data for the Canal Creek study
area indicates that nickel is one of the most common inorganic constituents to exceed the former MCL
level of 100 ug/L, with samples from at least a dozen wells in five widely separated areas having such
levels of nickel (Canal Creek Study Area, Remedial Investigation Progress Report, Edgewood Area,
Aberdeen Proving Ground, Maryland. Jacobs Engineering Group. September 1995). The available data
are not adequate to determine if the nickel detected in the Cluster 3 area is from upgradient sources within
the Canal Creek study area.
The risk assessment did not identify nickel as a final constituent of concern for groundwater. There is no
longer an MCL for nickel, and the groundwater at Cluster 3 is a Type III aquifer to which MCLs do not
apply,
Comment No. 27: "Gross beta readings were found to be elevated compared to background at WBR-03,
WBR-04 and WBR-10, at concentrations of 31, 24 and 97 pCi/L, respectively. In addition to our
concerns regarding the migration of contaminants at WBR-03. as discussed previously, APGSCC is also
concerned about the presence of elevated radiological data in groundwater so close to on-post housing
(less than 200 feet). It should be noted that gross alpha was also detected at this well at 25 pCi/L+/-10,
which would place it at the MCL for alpha radioactivity of 15 pCi/L. Gross beta was found consistently
at this location between 90 and 110 pCi/L for three consecutive rounds. The RAD risk discussion in
36
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n concems generated by these data. In fact, section 6.3 the MCL for Radium
and Ra-228 combined is 5 pCi/L while Ra-226 was detected in the groundwater at Cluster 3 at
7.7 pCi/L. A proposed rule was mentioned for Ra-226 of 20 pCi/L in the text, but the significance of this
proposed rule versus the current standard is not discussed."
Response No. 27: The elevated gross beta levels are due to naturally occurring potassium-40
Of the three mentioned wells, only for WBR-10 did groundwater samples consistently show high gross
beta. The groundwater samples from this well were also quite high in total potassium, with detected
concentrates ranging up to 94.5 rng/L. For this total potassium level, the nonvolatile beta activity due
to naturally occurring K-40 : would be approximately 80 pCi/L. In the sampling of a monitoring well, it is
common for there to be substantial variation in amounts of suspended solids between sample containers
S- ^ r1? ^L I'6', Th0 SamP'ing Pla" f°r C1UStCr 3 Spedfied that the samP'e 'ontainer fT
radionuchdes be the last contamer filled. As the last container filled, it would have normally contained
the greatest amount of suspended solids, and with analysis of unfiltered samples, would have caused gross
beta measurements to be elevated due to K-40. The elevated levels of total potassium in samples from
this well are due to grout contamination within the screened interval created during well installation
fromlhis teH ""^ characteristic of Srout contamination, is also observed in water samples
As noted in the response to other comments, the gamma spectrometry -methodology for water commonly
provides erroneous results for Ra-226. , ^'»«»ui"y
Ir^TH^ thC ladi°cl|emistry data for Cluster 3 does not show any evidence of contamination by
radionuchdes, with results being consistent with naturally occurring levels and variability typical for
gamma spectrometry analysis.
Comment No. 28: 'This same section mentions that RESRAD was used to back-calculate acceptable
sotl concentrations, but does not discuss how the groundwater issue was evaluated APGSCC requests
that the presence of this radiological contamination be evaluated under the best risk assessment
procedures available and that APG evaluate possible sources for such contamination, including naS
cotTf tTRgF?LPn S Hf8- TTake thlS PrOC6SS transParent to *« Public, the TAG Group needs a
copy of the RESRAD model to evaluate its design. Furthermore, APG, the EPA and APGSCC need to
meet to assess the input parameters used in the model for APG. Lastly, the risk evaluation process must
be clearly delineated within the text of the CERCLA documentation for this and other APG siteTof
frnr^- ' remamS imperative that APG develop a comprehensive, clear approach for assessing risk
IZnrtn hT /°T """"L10"' 3nd the "^ t0 ade1uately eva'"*e radiological risk at Cluster 3 is
supported by the data from other media discussed below."
Response No. 28: Please see Response No. 18 for a discussion on handling of groundwater. A clear and
m^SmrenTiSSme ^ aSS6SSment for radio™clides has been adopted by APG, and will be seen
Comment No. 29: "Lead was found in a few surface water samples collected, with at least one sample
exceeding its water quality criterion. While the proposed plan does not identify it as such, the comparison
criterion used in this assessment appears to be the acute concentration, which is much higher than the
chronic criterion. Given that the landfill is a constant source in the area and continuously releasing
contamination, it is not clear why the acute criterion has been accepted in this assessment. Furthermore, a
37
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majority of the samples analyzed were collected in two rounds during a fairly small time window between
October 24 and November 13, 1996. It is questionable whether this sampling approach would give a
reasonable picture of contamination, considering the various environmental factors from one season to the
next that would influence run-off, contaminant solubility, etc. In support of this concern, it is worth
noting the samples that revealed surface water contamination in excess of the water quality criteria were
collected in early September and late March, both months of which represent environmental conditions
considerably different than the last October/early November time period. Gross beta readings were found
in both surface water samples at fairly consistent concentrations. 58 and 73 pCi/L, respectively. This is
worth noting since a considerable distance separates the two sampling points. While the RI Report notes
that the concentrations were much lower in the second round, this is not surprising since consistent
detections in surface water is not common for sites where ground water discharge or surface runoff are the
most likely avenues for this contamination to reach the surface water body. APGSCC requests that
additional surface water sampling be conducted to evaluate the persistence of the lead and radiologicals."
Response No. 29: APG recognizes that a thorough understanding of contaminant transport from the
OBRRD via surface water and sediment is important. While the proposed remedy for the OBRRD will
eliminate releases from the source area, it is important that monitoring measure the effectiveness of this
remedy, and also develop data that can be used to assess the long-term ecological risk associated with
constituents already in sediments of Lauderick Creek. APG is planning to conduct sampling and analysis
of sediment because constituents have migrated to nearby Lauderick Creek sediments via sediment
erosion and transport. The monitoring will include multiple sampling events from before until after
construction, and will include sediment chemistry as well as sediment bioassay. This monitoring will
assess seasonal effects and trends, and will include assessment using appropriate toxicity reference
values. APG is also considering the use of sediment bioassay as a long-term monitoring tool.
The types of constituents that are of concern at the OBRRD have a relatively low water solubility and
high soil/water partition coefficient, and as a result are primarily associated and transported with
sediments (as opposed to solute transport). Because of these characteristics, future monitoring will focus
on sediments rather than surface water. Transport of constituents will be associated with storms or other
events that disturb source areas or sediments, and will typically be short in duration.
Comment No. 30: 'These same issues exist for the few sediment samples collected. Specifically, lead
was found in both remedial investigation samples above the maximum reference concentration; for one
location the lead was present at a concentration 10 times greater than the BTAG criterion of 46.7 ppm.
Radiological contamination was also found in both remedial investigation sediment samples at 28 and 32
pCi/L. Interestingly, the man-made isotope cesium was present at both sites as well, although cesium-137
and potassium-40 were reported to be detected below background levels collected by the Maryland
Department of Natural Resources. Radium-226 was present in sediment at levels greater than background
(1.80 vs. 1.98 pCi/g). Lastly, we are concerned that the isotopes reported only account for 1/4 - 1/3 of the
gross beta measured in the sediments. While the lead contamination was mentioned in the PP, the
radiological contamination was not included. As acknowledged in the PP, sediment samples exceed the
BTAG criteria for metals. Upon review of the FS (fig. 1-10). these contaminants include arsenic,
beryllium, lead, mercury and nickel. From the data reviewed, it does not appear that there are many
samples from the marsh and Lauderick Creek outside the selected area for cap construction. With the
limited number of samples in Lauderick Creek, it is not clear that an adequate assessment of contaminant
migration and ecological impacts has taken place. APGSCC requests clarification as to the role the EPA
Biological Technical Assistance Group (BTAG) played in evaluating the ecological issues regarding
38
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Cluster 3 and the adjacent water body. Additionally, please explain why bioassays were not conducted
with regard to the contamination in the marsh surrounding the landfill and in Lauderick Creek?
Response No. 30: Please see responses to other comments concerning plans to assess metals in sediment
by sampling, chemical analysis, and laboratory bioassay testing. Please also see other comments
concerning the presence of naturally occurring and man-made radionuclides in environmental media as
well as the limitations of the gamma spectrometry method of analysis. There are no indications of
radionuclide contamination at Clusters or the OBRRD. Please see response to comment no 18 for
further discussion.
Please see responses to other comments concerning plans to assess metals in sediment by monitoring and
bioassay. Please also note that the-proposed remedy will prevent any further release of constituents from
source areas in the OBRRD, and that the remedy can be accomplished without further data assessing
impacts on Lauderick Creek. Bioassays have been performed with sediment samples collected within the
mam portion of Laudenck Creek and have not identified toxicity problems. That work did not address the
tributary portion of Laudenck Creek immediately downstream of the OBRRD, which will be the focus of
the planned, monitoring and assessment.
Comment No. 31: "Furthermore, the proposed plan asserts that the contamination in the sediments has
come from past or continuing slumping and erosion of the surface of the OBRRD Yet as acknowledged
in the previous sentence within the proposed plan (page 6), it is also possible that such contamination is
coming from the anomaly areas detected in the marsh (the push out areas). Given the 1) lack of sampling
conducted outside the area to be capped, 2) the data gaps regarding the source(s) of contaminants detected
m the segment samples that were collected in Lauderick Creek, and 3) the funds saved by cappine the
site instead or removing the source, APGSCC requests that additional sediment and surface water
sampling be implemented as part of the ROD and long-term monitoring efforts to further evaluate the
'" thC marSh and thC effectiveness of the caP in educing further deterioration of
Response No. 31: The push out areas mentioned are a part of the OBRRD and will be addressed by the
proposed remedy Then jis no further need to conduct sampling and analysis to support the remedial
decision process for the OBRRD. Sampling and analysis of sediment, as well as sediment bioassay is
planned to evaluate the implementation and effectiveness of the remedy, and to provide data necessary to
s risk associated with
APG believes that there is sufficient justification to proceed with remediation of the OBRRD as a source
area to ensure that there is no further release of constituents of concern to Lauderick Creek. The planned
monitoring will be separate from the decision process and ROD. allowing remediation to proceed.
n°* ^ "GT ^tawere elevated in a» soil samples collected from Cluster 3. Cesium was
present m all samples and other isotopes including radium-226 and thorium-228 were detected. Although
it is not discussed m the PP, the baseline risk assessment chapter in the RI notes that Ra-226 was detectfd
in sod and sediment at concentrations three and two times higher than concentrations corresponding to the
Yet' no other discussion takes iace i
39
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Response No. 33: Please see other responses related to radiochemistry and the natural and anthropogenic
occurrence of radionuclides. A review of the radiochemistry data for Cluster 3 does not show any
evidence of contamination by radionuclides, with results being consistent with naturally occurring levels
and variability typical for gamma spectrometry analysis.
COMMENTS FROM MARYLAND DEPARTMENT OF THE ENVIRONMENT
The Environmental Restoration and Redevelopment Program (EERP) of the Waste Management
Administration provided the following comment.
Comment No. 34: MDE noted there was an incorrect Code of Maryland Regulations (COMAR) citation
in the Proposed Plan and stated it should be deleted.
Response No. 34: APG has deleted the reference.
40
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U.S. ARMY WVHcS PUBLiC CMMENT
•
ON pn
ron
.^berdee* ProTtaf Qiwaw***^'
mbUetocmtttMii*
0*ttor**^,W*^"^V^*/*G'*
Mil
•Ro*ddu*pcUej
The public nay «obmUwniieyra>i»-;
menu on the Proposed Phm deitaf thW-
Idty comment period which ren> N*H«ff
3 Mo September 14.1998. CSmmeWr^sl
be postmtrked by September .I4:ihd av be
sentto: ..'.'-.
Mr.KeKSttdilw . •"','-"
U.S. Arar Omison. ATTN: STEAMrM*
5n9H
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MARYLAND DEPARTMENT OF THE ENVIRONMENT
2500 Broemng Highway • Baltimore Maryland 21224
(410)631-3000 • 1-800-633-6101 • http://www.mde. state, rnd. us
Parris N. Glendening j^g -p
Governor '„
Secretary
October 15, 1998
Mr. Ken Stachiw
Directorate of Safety, Health and Environment
U.S. Army Aberdeen Proving Ground Support Activity
Aberdeen Proving Ground MD 21005-5001
RE: Bush River Study Area. Edeewood Area. APG. Proposed Plan. Cluster 3. Site 3. Old
Bush River Road Dump July 1998 ,
Dear Mr. Stachiw:
The Maryland Department of the Environment, Waste Management Administration
(MDE/WAS) has reviewed the above-referenced document. This review indicated that a Code
of Maryland Regulations (COMAR) citation was incorrectly referenced in the subject document
as an Applicable or Relevant and Appropriate Requirement (ARAR). Unfortunately during the
development of the Feasibility Study for this site, the Federal Facilities Section of the
Environmental Restoration and Redevelopment Program (ERRP) erroneously identified the
citation from COMAR 26.13.14 as a potential ARAR for the subject action. The error was then
transferred to your document.
Once this error was identified, the correct citation was reviewed in some detail
Following the revaluation of COMAR 26.13.05.14, which is in the State's Hazardous Waste
regulations, ERRP does not believe that the cited COMAR is more stringent than the equivalent
Federal regulation. Therefore, COMAR 26.13.05.14 should not be considered State ARAR for
this action. Please revise the subject document by deleting the reference to COMAR 26.13.14.
The subject document adequately presents the Army's proposal to construct a soil cover
on the Old Bush River Road Dump. The action is expected to reduce further erosion and
mitigate exposure to unexploded ordnance. This action will address the concerns identified
during the remedial investigation of this site, principally, further erosion of material at the site
and direct exposure to unexploded ordnance buried at the site. The Army's commitment to long-
term monitoring will further ensure that the action sufficiently addresses site concerns. The
ERRP considers the actions proposed by the Army to be appropriate to the circumstances at this
site.
-------
Mr. Ken Stachiw
Page 2
If you have any questions, please contact me at (410) 631-3440.
Sincerely,
cc: Mr. Steve Hirsh
Mr. Richard Collins
Ms. Hilary Miller
Ms. Shari Wilson
John Fairbank, Chief
Federal/NPL Superfund Division
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