EPA/ROD/R02-96/276
1996
EPA Superfund
Record of Decision:
NAVAL SECURITY GROUP ACTIVITY
EPA ID: PR4170027383
OU02
SABANA SECA, PR
09/20/1996
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FINAL
RECORD OF DECISION
SITE 6, FORMER PEST CONTROL SHOP
NAVAL SECURITY GROUP ACTIVITY
SABANA SECA, PUERTO RICO
CONTRACT TASK ORDER 0279
SEPTEMBER 27, 1996
Prepared For:
DEPARTMENT OF THE NAVY
ATLANTIC DIVISION
NAVAL FACILITIES
ENGINEERING COMMAND
Norfolk, Virginia
Under the:
LANTDIV CLEAN Program
Contract N62470-89-D-4814
Prepared By:
BAKER ENVIRONMENTAL INC.
Coraopolis, Pennsylvania
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TABIiE OF CONTENTS
Page
LIST OF ACRONYMS AND ABBREVIATIONS iv
DECLARATION V
1.0 SITE NAME, LOCATION, AND DESCRIPTION 1
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 1
2.1 Site History 1
2.2 Previous Investigations/Enforcement Activities 2
2.2.1 Initial Assessment Study 2
2.2.2 National Priorities Listing 2
2.2.3 Confirmation Study 3
2.2.4 Remedial Investigation/Feasibility Study 3
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION 5
4.0 SCOPE AND ROLE OF THE RESPONSE ACTION 5
5.0 SUMMARY OF SITE CHARACTERISTICS 6
6.0 SUMMARY OF SITE RISKS 7
6.1 Human Health Risk Assessment 7
6.2 Uncertainty Analysis 8
6.3 Ecological Risk Assessment 10
7.0 REMEDIAL ACTION OBJECTIVES 11
8 . 0 DESCRIPTION OF ALTERNATIVES 11
9.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES 13
9.1 Overall Protection of Human Health and the Environment 14
9.2 Compliance with ARARs 14
9.3 Long-Term Effectiveness and Permanence 14
9.4 Reduction of Toxicity, Mobility, or Volume Through Treatment 14
9.5 Short-Term Effectiveness 14
9.6 Implementability 14
9.7 Cost 14
9. 8 USEPA/Commonwealth Acceptance 15
9. 9 Community Acceptance 15
10. 0 SELECTED REMEDY 15
10.1 Remedy Description 15
10.2 Estimated Costs 15
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TABLE OF CONTENTS
(Continued)
Page
11. 0 STATUTORY DETERMINATIONS 15
11.1 Protection of Human Health and the Environment 16
11.2 Compliance with Applicable or Relevant and Appropriate Requirements 16
11.3 Cost-Effectiveness 16
11.4 Utilization of Permanent Solutions and Alternative Treatment Technologies ... 16
11.5 Preference for Treatment that Reduces Toxicity, Mobility, or Volume as a
Principal Element 16
12 . 0 RESPONSIVENESS SUMMARY 16
12 .1 Overview 16
12.2 Background on Community Involvement 16
12.3 Summary of Comments Received During the Public Comment Period and
Agency Responses 17
TABLES
1 Chemicals of Potential Concern for the Human Health Risk Assessment
2 Exposure Pathways
3 Toxicity Values - RfD
4 Toxicity Values - Slope Factors
5 Summary of Pathway - Specific Risks
FIGURES
1 Vicinity Map
2 Site Map
3 Approximate Areas of Soil Contaminated Above TBC Criteria
4 Alternative 2 - Capping
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ARAR
CERCLA
COPC
DOD
ELCR
FFA
FS
HI
IAS
* tg/kg
* tg/L
ing/kg
MCL
NPL
NPW
NSGA
PCBs
PREQB
RA
RAA
RAGS
RCRA
RfD
RI
RI/FS
ROD
SVOCs
TBC
TRC
TSCA
UCL
US EPA
Versar
VOCs
LIST OF ACRONYMS AND ABBREVIATIONS
applicable or relevant and appropriate reguirements
Comprehensive Environmental Response, Compensation and Liability Act
contaminant of potential concern
Department of Defense
Excess Lifetime Cancer Risk
Federal Facilities Agreement
Feasibility Study
hazard index
Initial Assessment Study
micrograms per kilogram
micrograms per liter
milligrams per kilogram
Federal Maximum Contaminant Level
National Priorities List
net present worth
Naval Security Group Activity
polychlorinated biphenyls
Puerto Rico Environmental Quality Board
Risk Assessment
remedial action alternative
Risk Assessment Guidance for Superfund
Resource Conservation and Recovery Act
Reference Dose
Remedial Investigation
Remedial Investigation/Feasibility Study
Record of Decision
semivolatile organic compounds
To Be Considered criteria
Technical Review Committee
Toxic Substances Control Act
Upper Confidence Limit
United States Environmental Protection Agency
Versar, Inc.
volatile organic compounds
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DECLARATION
Site Name and Location
Site 6 - Former Pest Control Shop
Naval Security Group Activity
Sabana Seca, Puerto Rico
Statement of Basis and Purpose
This decision document presents the selected remedy for Site 6 at the Naval Security Group
Activity (NSGA) Sabana Seca. The remedy was chosen in accordance with the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act (SARA), and, to the extent practicable, the
National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This decision is based
on the administrative record file for Site 6, the Former Pest Control Shop.
Assessment of the Site
Navy investigation and study has found no unacceptable risk to human health or the environment
from the pesticide contamination of soil that has occurred in this area. Nevertheless, the site
is adjacent to a playground/picnic area and the enlisted housing area. Therefore, as a
reassurance to the public, the Navy is conservatively selecting a remedial alternative that will
limit the public's exposure to the minimal contamination that may remain in the soil at Site 6.
Description of Selected Remedy
The selected remedy for Site 6 is an asphalt cap over the areas where pesticides were previously
detected in the surface soils. The fence that is currently around portions of Site 6 will be
removed. The area will be cleared and grubbed. An eight inch sub-base layer of gravel will be
placed in the area to be capped. A four inch layer of asphalt will be placed over the gravel
sub-base layer. The surface of the cap will be sloped to drain. The area around the cap will
be leveled with clean fill and the site will be revegetated.
Statutory Determinations
The selected remedy is protective of human health and the environment and complies with Federal
and Commonwealth reguirements that are legally applicable or relevant and appropriate, and is
cost effective. Though there is no unacceptable risk to human health or the environment from
Site 6, because of its proximity to adjacent playground/picnic and housing areas, this
pro-active remedy is being selected to limit the public's exposure to the minimal contamination
that may remain in soils at the site. Became this remedy will not result in hazardous
substances remaining on site above health-based levels, the five year review will not apply to
this action.
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Signature (Commanding Officer, NSGA Sabana Seca) Date
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Signature (Chairman, Puerto Rico Environmental Quality Board) Date
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Signature (Regional Administrator, USEPA Region 2) Date
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1.0 SITE NAME, LOCATION, AND DESCRIPTION
The Naval Security Group Activity (NSGA) Sabana Seca provides communications and support for
the U.S. Navy and other Department of Defense (DOD) elements. NSGA Sabana Seca is located
approximately 14 miles west of the city of San Juan on the island of Puerto Rico. The Activity
consists of a North and South Tract together covering over 2,200 acres of land. This Record of
Decision (ROD) is for Site 6, the Former Pest Control Shop, in the South Tract.
Figure 1 presents a map of the South Tract and the location of Site 6 within the South Tract.
As shown, the South Tract is bounded to the north by the village of Sabana Seca, to the east by
Route 866, to the south by Route 22, and to the west by the Toa Baja and Bayamon Municipal
Landfills and the U.S. Department of Health and Human Services Research Facility.
Figure 2 presents a map of Site 6 and shows the adjacent property uses. Site 6 covers an area
of approximately 11,050 sguare feet. The site is surrounded by a chain link fence that was
installed in 1988. Site 6 is bordered to the south by Stone Road which is the main road through
the Activity. An access gate to the site is located along Stone Road. The enlisted base housing
is south and across Stone Road from Site 6. A playground/picnic area is north and west of Site
6. The area northeast and east of the site and the immediate area around Site 6 are maintained
lawns. Areas to the west outside of the maintained lawns are heavily vegetated and not
developed. The Pest Control Shop building was formerly located in the north-central portion of
the site. The site is currently overgrown with vegetation inside the fenced area.
Site 6 is located north of the geologic region known as the Haystack Hills. Haystack Hills is
the local name given to an area featuring karst topography, characterized by steeply sloped
limestone hills, sinkholes, and caves. The area around Site 6 is relatively flat.
The only surface water present at Site 6 results from the accumulation of rain water into a low
area east of the site. There is no surface water present during the drier seasons. Groundwater
flow in the area is generally to the north-northeast.
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
NSGA Sabana Seca was placed on the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) National Priorities List (NPL) on October 4, 1989. The United States
Environmental Protection Agency (USEPA) Region II; the Puerto Rico Environmental Quality
Board (PREQB); and the United States Department of the Navy then entered into a Federal
Facilities Agreement (FFA) for NSGA Sabana Seca in March, 1992. The primary purpose of the FFA
was to ensure that environmental impacts associated with past and present activities at the
Station were thoroughly investigated and appropriate CERCLA response/Resource Conservation and
Recovery Act (RCRA) corrective action alternatives were developed and implemented as necessary
to protect public health and the environment.
The following sections describe history and previous investigations conducted at Site 6.
2.1 Site History
Site 6 was operational as a pest control shop from the mid-1950s through 1979. Pesticides were
accidentally spilled in and around the building during this time. Pesticides were stored in a
small concrete building and on concrete pads adjacent to the building. Pesticides were mixed
and application eguipment cleaned in a sink outside the building which discharged directly to
the ground. Drainage from the site flows north to the eastern perimeter of the Station's
picnic/playground area. The pesticides reportedly used or stored at this site in the past
included: DDT, lindane, chlordane, Paris Green, 2,4-D, malathion, diazinon, sevin, PRAMITOL,
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and esteron (a mixture of 2,4-D and 2,4,5-T). Paris Green is an arsenic-based insecticide, and
PRAMITOL is a non-selective herbicide of the triazine family that is adsorbed by foliage and
roots and inhibits photosynthesis.
In October 1987, the materials stored in the pesticide shop were removed and taken to the
Station's hazardous storage facility and the building was demolished. The demolition debris
including concrete, shingles, etc., were taken to the nearby Bayamon/Toa Baja municipal
landfill. A clean layer of topsoil was placed on the site, and the area was vegetated. As
previously mentioned, the site was enclosed in a chain-link fence to limit public access. The
fence gate is locked at all times. Warning signs are posted in English and Spanish. This area
along Stone Road is patrolled regularly by military police.
In February and March 1989, the Station disposed of computers and communications eguipment
cabinets at Site 6. Electric components containing Polychlorinated Biphenols (PCBs) were
removed from the eguipment cabinets and disposed off site in accordance with the Toxic
Substances Control Act (TSCA) . The eguipment (radio) cabinets were then stored at Site 6 on top
of a heavy gauge plastic (Refer to Figure 2). PCB-bearing components were never stored at Site
6, and no PCBs have been detected at the site. The eguipment cabinets are scheduled for removal
and disposal in the third guarter of 1996.
2.2 Previous Investigations/Enforcement Activities
A summary of the previous investigations conducted at Site 6 is presented below.
2.2.1 Initial Assessment Study
In 1984, an Initial Assessment Study (IAS) was conducted for the Station. The purpose of the
IAS was to identify and assess sites posing a potential threat to human health or to the
environment due to contamination from past hazardous material operations. This IAS involved
reviewing historical records and aerial photographs, and conducting on-site inspections and
personnel interviews.
During the IAS, one 55-gallon drum of 57-percent malathion was found stored inside the building,
and one 55-gallon drum of chlordane was found stored outside on the concrete pad. Pesticide
odors were noted. The IAS concluded the possibility of contaminants from the site could migrate
via both surface water and groundwater. The IAS concluded that Site 6 warranted further
investigation.
2.2.2 National Priorities Listing
NSGA Sabana Seca was proposed for inclusion on the NPL on June 24, 1988 and was included Oil
October 4, 1989. In March 1992, the Navy, USEPA, and the PREQB entered into a FFA for NSGA
Sabana Seca.
2.2.3 Confirmation Study
Between 1986 and 1989, a Confirmation Study was conducted by Hunter/ESE. Two rounds of
sampling were conducted for this study.
Round 1 consisted of collecting and analyzing 2 sediment and 34 soil samples. No surface water
or groundwater samples were taken during Round 1. Round 2 consisted of installing one shallow
groundwater monitoring well (S6GW01SL) east of the Former Pest Control Shop location and of
collecting and analyzing two sediment, two surface water, and one groundwater sample. The
sediment and surface water samples were taken from approximately the same location as the Round
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1 sediment sample locations. No soil samples were taken during Round 2.
The soil analyses indicated that the pesticides aldrin, chlordane, DDD, heptachlor, and
heptachlor epoxide were detected at concentrations ranging from 0.295 milligrams per kilogram to
41.0 milligrams per kilogram. Chlordane was detected in all soil samples. The sediment
analyses indicated that the pesticides aldrin, BHC-D, chlordane, and heptachlor epoxide were
detected at concentrations ranging from 0.0128 milligrams per kilogram (BHC) to 88.5 milligrams
per kilogram (chlordane). No pesticides were detected in the groundwater or the surface water
exceeding the analytical detection limits.
2.2.4 Remedial Investigation/Feasibility Study
Between October 1991 and October 1993, Versar, Inc. (Versar) conducted the field sampling
activities for the RI/FS at Site 6. Field activities included installing monitoring wells;
conducting aquifer tests; collecting groundwater, soil, surface water and sediment samples;
surveying; and collecting soil geotechnical samples. The sampling was conducted in four rounds.
The results of the RI field investigation are summarized below with respect to the sampled
media.
Groundwater
Soil
A rising head slug test was conducted at monitoring well S6GW03SL. The data
were evaluated using the method of Bouwer and Rice (1976) and Bouwer (1989).
The hydraulic properties were calculated from this test include the hydraulic
conductivity (1.9x10-6 ft/min) and transmissivity (2.8x10-4 ft2/min).
After extensive groundwater level monitoring, the groundwater flow direction at
Site 6 is generally toward the north. The RI concluded that groundwater at Site 6
is not impacted by the nearby Toa Baja/Bayamon Landfills, and that Site 6 does not
impact the Station's water supply wells.
The volatile organic compounds (VOCs), toluene, acetone and xylene, were detected at
maximum concentrations of 12, 10, and 13 micrograms per liter, respectively.
Three semivolatile organic compounds (SVOCs) were detected in four rounds: bis
(2-ethylhexyl)phthalate, di-n-octylphthalate, and phenol at concentrations ranging
from 1 to 70 micrograms per liter.
No pesticides, PCBs, or herbicides were detected in any of the four sampling rounds.
Two metals, iron and manganese, were detected in all four rounds of sampling in
well S6GW01SL (located 60 feet northeast of the site). With only one minor
exception, no metals were detected above Federal Maximum Contaminant Levels (MCLs)
groundwater standards in four rounds of sampling. Chromium was detected at 119
micrograms per liter versus the MCL of 110 micrograms per liter.
A VOC, toluene, was detected at concentrations ranging from 0.005 to 0.015
milligrams per kilogram.
Three SVOCs were detected: di-n-butylphthalate, bis(2-ethylhexyl)phthalate, and
di-n-octylphthalate at concentrations ranging from 0.086 to 1.40 milligrams per
kilogram.
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• No herbicides or PCBs were detected in the soil samples.
• Four pesticides were detected: heptachlor, heptachlor epoxide, alpha-Chlordane,
and gamma-Chlordane. The detected concentrations ranged from 0.0037 milligrams per
kilogram to 27 milligrams per kilogram.
• Six metals were detected: aluminum, arsenic, chromium, cobalt, selenium, and
vanadium at concentrations ranging from 1.6 to 58,800 milligrams per kilogram.
These detections were in the area of the former pest control shop.
Surface Water
• Surface water was only present during the wet season.
• The VOC, toluene, was detected in one round of surface water samples at
concentrations of 95 micrograms per liter and 110 micrograms per liter.
• The SVOCs, phenol, 3-methylphenol, and 4-methylphenol were detected in one
round of surface water samples. The detected concentrations ranged from 42 to
130 micrograms per liter.
• No pesticides, PCBs, or herbicides were detected in the surface water samples.
• Four metals were detected in the samples: antimony, arsenic, manganese, and zinc
at concentrations ranging from 4.1 to 176 micrograms per liter. No trends were
identified.
• Cyanide was detected with concentrations ranging from 1.8 to 2.3 micrograms per
liter.
Sediment
Surface water is only present during the wet season. When surface water was
present the samples collected under the surface water were considered sediment.
When the site is dry the sediment is considered to be soil.
The only VOC detected in the sediment samples was methylene chloride at
concentrations ranging from 0.008 to 0.010 milligrams per kilogram.
No SVOCs, PCBs, or herbicides were detected in the sediment samples.
Seven pesticides were detected: heptachlor epoxide; endosulfan I; 4,4'-DDE;
4,4'-ODD; endosulfan sulfate; alpha-Chlordane; and gamma-Chlordane. The
detected concentrations ranged from 0.013 milligrams per kilogram to 0.500
milligrams per kilogram.
The metals calcium (6.67 milligrams per kilogram) and zinc (0.493 milligrams per
kilogram) were detected in the sediment samples at one station, which is located
furthest from Site 6.
Arsenic was detected at concentrations of 0.0007 to 0.0091 milligrams per kilogram.
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3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
The RI/FS and Proposed Plan documents for Site 6 were released to the public in May 1996. These
documents are available in an administrative record file at information repositories maintained
at a local public library and at the Station library. The Proposed Plan is available in English
and Spanish. Technical Review Committee (TRC) members have participated in the review of draft
documents and have worked together to finalize these documents. The notice of availability of
the Proposed Plan and RI/FS documents was published in the local papers in English and Spanish.
A public comment period was held from May 15, 1996 to June 15, 1996. In addition, a Public
Awareness Session, in lieu of a public meeting, was held on June 7, 1996, to respond to
guestions and to accept public comments on the Proposed Plan for Site 6. A Responsiveness
Summary is included as part of this ROD. In the Responsiveness Summary, the Navy usually
addresses public comments, however, no comments were received during the public comment period
or at the Public Awareness Session.
4.0 SCOPE AND ROLE OF THE RESPONSE ACTION
An asphalt cap over part of Site 6 is the only remedial action proposed for the various media.
Though it has been concluded that there are no unacceptable risks at the site, a remedial action
has been proposed. The remedial action will consist of clearing and grubbing the site, placing
clean soil fill on the site, and installing an asphalt cap over areas where pesticides were
formerly detected in the soil. This response action was selected due to the proximity of the
site to playgrounds and housing areas. The goal of this selected remedy is to prevent human or
environmental contact with soil that may contain minimal residual amounts of pesticide
contamination.
5.0 SUMMARY OF SITE CHARACTERISTICS
This section of the ROD presents an overview of the nature and extent of contamination with
respect to the known or suspected sources of contamination, types of contamination, and affected
media. Based upon the RI and the site history, the source of contamination is the Former Pest
Control Shop that was located at the site. No additional sources of contamination were
identified. In general, groundwater was encountered at 40 feet below the ground surface. Two
water supply wells were identified within a one-mile radius of Site 6. Groundwater does not
appear to have been impacted by past practices at Site 6. There is no pattern of site-related
groundwater contamination identified. Federal groundwater standards were not exceeded in any
sample collected from downgradient monitoring wells.
The metals detected during the groundwater sampling and their maximum detected concentrations
are listed below:
aluminum 9,280 micrograms per liter
chromium 119 micrograms per liter
cobalt 33.6 micrograms per liter
iron 206,000 micrograms per liter
lead 14.5 micrograms per liter
manganese 1,080 micrograms per liter
mercury 0.43 micrograms per liter
nickel 31.8 micrograms per liter
potassium 108,000 micrograms per liter
vanadium 122 micrograms per liter
zinc 230 micrograms per liter
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Metals were only found consistently in one well, S60W01SL, which is not downgradient of Site 6.
None of the metals detected in the downgradient wells (S6GW03SL and S6GW02SL) exceeded
Federal MCLs. Metals concentrations cited were either detected in background wells, were
isolated detections, were found in samples not downgradient from the site, or at low
concentrations. Therefore, no trends of metals in the groundwater were attributed to former
activities at Site 6.
The soils underlying the site generally consist of clay with some sand, silt, and weathered
rock. The sediment and soil at Site 6 have been impacted by the activities at the former pest
control shop. Soil contamination is dominantly pesticides with a minor contribution of toluene,
phthalates and metals. The pesticides detected in the soil and sediment, and their maximum
concentrations, included:
• heptachlor epoxide 0.19 milligrams per kilogram -soil
• heptachlor 0.0078 milligrams per kilogram - soil
• endosulfan-I 0.061 milligrams per kilogram - sediment
• endosulfan sulfate 0.035 milligrams per kilogram - sediment
• 4,4-DDD 0.14 milligrams per kilogram - sediment
• alpha Chlordane 20 milligrams per kilogram - soil
• gamma Chlordane 27 milligrams per kilogram - soil
Pesticides are generally highest in concentration in the immediate vicinity of the former shop.
Data from the sediment samples are similar to that for soil data, but at lower concentrations.
Figure 3 shows the approximate area of contaminated soil.
Rainfall water runoff sometimes ponds in a low area adjacent to the site. Where the
intermittent ponding occurs, the soil samples have been called sediment samples and the water
samples have been called surface water samples. Remediation of the soil and sediment would
eliminate any potential surface water contamination problem.
6.0 SUMMARY OF SITE RISKS
As pan of the RI/FS, a human health Risk Assessment (RA) and an ecological RA were conducted
for Site 6. These RAs evaluated the potential risks associated with Contaminants of Potential
Concern (COPCs) detected at each site. The following subsections briefly describe the results
of the RAs. The RI/FS report contains more extensive information pertaining to the RAs.
6.1 Human Health Risk Assessment
A four-step process is used for assessing site-related human health risks for a reasonable
maximum exposure scenario. Hazard Identification identifies COPCs at the site based on several
factors such as toxicity, freguency of occurrence, and concentration. Exposure Assessment
estimates the magnitude of actual and/or potential human exposures, the freguency and duration
of these exposures, and the pathways (e.g., drinking contaminated well water) by which humans
are potentially exposed. Toxicity Assessment determines the types of adverse health effects
associated with chemical exposures, and the relationship between magnitude of exposure (dose)
and severity of adverse effects (response). Risk Characterization summarizes and combines
outputs of the exposure and toxicity assessments to provide a guantitative assessment of
site-related risks.
The human health RA was conducted to estimate the potential risks to human health resulting from
contaminant releases from Site 6. Groundwater was eliminated as a pathway of concern because
pesticides were not detected during the four rounds of sampling and no trends were noted in the
other detected compounds. The media of potential concern identified at the site were surface
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soil, surface water, and sediment. Analytical results from the RI identified VOCs, SVOCs,
pesticides, metals, and cyanide as COPCs. Table 1 contains a summary of the COPCs for each
media of concern. Table 2 lists the exposure pathways. Tables 3 and 4 show Toxicity Values.
The Summary of Pathway - Specific Risks is shown on Table 5.
The exposure routes evaluated for this RA included: incidental ingestion and dermal absorption
of surface soils by future potential recreational and residential children and adults;
incidental ingestion of surface soils by future potential commercial adult workers; dermal
absorption during contact with surface water by future potential recreational pro-adolescent
children; and dermal absorption during contact with sediments by future potential recreational
pre-adolescent children. Recreational scenarios were evaluated since the site is located next
to a playground/picnic area.
As part of this RA, the potential carcinogenic and noncarcinogenic risks were estimated for the
COPCs at the site. Carcinogenic risks are the estimated incremental probability of an
individual developing cancer over a lifetime because of exposure to a potential carcinogen.
Current federal guidelines for acceptable carcinogenic risks are in the range of 1 x 10-4 to 1 2
10-6 (one in ten thousand to one in one million). A noncarcinogenic risk is the likelihood of
developing adverse health effects other than cancer resulting from a long-term (chronic)
exposure to a noncarcinogenic COPC. Noncarcinogenic risk is expressed as a hazard index (HI),
which is the ratio of the level of exposure to an acceptable level for all COPCs within a
particular exposure pathway. If the HI is less than 1.0, the hazard is not considered a public
health threat. The Excess Lifetime Cancer Risk (ELCR) calculated for Site 6 ranged from 4.0 x
10-6 (four in one million) to 3.8 x 10's (3.8 in one hundred thousand). The His calculated for
the site ranged from 0.0024 to 0.993. These ELCRs and His are within the acceptable ranges.
The human health RA concluded that no media at Site 6 posed unacceptable risks or hazards to
human health for the current or future use scenarios.
6.2 Uncertainty Analysis
Despite recent advances in risk assessment methodology, uncertainties are inherent in the risk
assessment process. In order to appreciate the limitation and significance of the risk
estimates, it is important to have an understanding of the sources and magnitudes of
uncertainty. Sources of uncertainty in this risk assessment, as in any risk assessment,
include:
• Sampling and analysis error,
• Chemical transport and fate modeling,
• Toxicity data,
• Exposure assessment, and
• Risk estimates.
Environmental Media Sampling and Analysis
Sampling was conducted using accepted procedures in an attempt to collect samples that were
representative of environmental media. Analyses were performed in accordance with the USEPA
procedures. Data were subsequently reviewed in a data validation process; however, current
analytical procedures may not identify all potentially hazardous contaminants at a site, and
analytical errors may have occurred despite stringent QA/QC procedures. In conducting this risk
assessment, it was assumed that the reported chemical concentrations were representative of
actual site conditions.
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Chemical Transport and Fate Modeling
The 95th percentile upper confidence limit (UCL) (or maximum) concentrations of chemicals of
potential concern found in soil, dust, sediment, and water on site were used as exposure point
concentrations. Migration, dispersion, dilution, retardation, degradation, and other
attenuation or transformation processes may occur over time that could change the chemical
concentrations in various on-site medias. It has been conservatively assumed that the
concentrations observed at Site 6 will remain relatively unchanged with time because, with the
exception of the VOC toluene, all chemicals of concern are relatively persistent and immobile.
Toxicity Data
The available scientific data on subchronic and chronic toxic effects in humans for the
chemicals of concern found at Site 6 are limited. Conseguently, varying degrees of uncertainty
surround the assessment of adverse health effects in potentially exposed populations. Sources
of uncertainties for toxic effects in humans include:
• Use of dose-response data from experiments on homogeneous, sensitive animal
populations to predict effects in heterogenous human populations with a wide range
of sensitivities;
• Extrapolation of data from high doses in animals to "real-world" low doses, from
acute or subchronic to chronic exposure, and from one route to another, (e.g., from
ingestion to dermal absorption); and
• Use of single chemical data that do not account for possible antagonistic or
synergistic responses from multiple chemical exposures.
Toxicity data are largely derived from laboratory animals. Experimental animal data have
historically been relied upon by regulatory agencies and other expert groups to assess the
hazards of chemicals to humans. Although this reliance has been supported by empirical
observations, there may be slight or marginal interspecies differences in the absorption,
metabolism, excretion, detoxification, and toxic responses to specific chemicals of concern.
There may also be uncertainties concerning the relevance of animal studies using exposure routes
that differ from human exposure routes. In addition, the freguent necessity to extrapolate
results of short-term or chronic animal studies to humans exposed over a lifetime has inherent
uncertainties. In order to adjust for many of these uncertainties, USEPA often adjusts the
reference dose (RfD) for noncarcinogenic effects using uncertainty and modifying factors on the
most sensitive animal species.
There is also uncertainty as to whether animal carcinogens are also carcinogenic in humans.
While many chemical substances are carcinogenic in one or more animal species, only a small
number of chemical substances are known to be human carcinogens. The fact that some chemicals
are carcinogenic in some animals, but not in others, raises the possibility that not all animal
carcinogens are carcinogenic in humans. USEPA assumes that humans are as sensitive to
carcinogens as the most sensitive animal species. This policy decision, designed to prevent
underestimating risk, may introduce the potential to overestimate carcinogenic risk for some
chemicals.
The model used by USEPA to determine slope factors is the linearized multistage model that
provides a conservative estimate of cancer risk at low doses and may overestimate the actual
slope factor. Inadeguate knowledge of the validity and accuracy of the linearized multistage
model may increase the uncertainty and the tendency to overestimate actual cancer risks.
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When dealing with exposures to chemical mixtures, USEPA assumes dose additivity and does not
account for potential synergisms, antagonisms, differences in target organ specificity, or
mechanisms of action.
Despite these many limitations, animal experiments are widely believed to be a necessary part of
toxicity assessment, especially in the absence of human epidemiological data. The safety
factors used in RfD derivations for single chemicals may compensate for any unknown effects of
synergistic exposures.
Exposure Assessment
Exposure assessment is perhaps the most critical step in achieving a reliable estimate of health
risks to humans. In this assessment, a number of assumptions were made concerning the human
populations that could come into contact with Site 6 media and the freguencies and durations of
these contacts. The exposure parameters used in this assessment were largely based on USEPA's
Risk Assessment Guidance for Superfund (RAGS) and Exposure Factors Handbook, and may not be
representative of the current and future receptor populations. There is also the presumption
that interim and institutional measures at the site would not lead to changes in exposure
conditions and receptor behaviors.
In accordance with USEPA Headguarters and USEPA Region 2 guidance, reasonable maximum exposures
were calculated to provide estimates of potential exposures. Because reasonable maximum
exposure estimates are based on a combination of conservative assumptions, these estimates are
likely to be overestimates of typical exposures and risks at Site 6.
Risk Estimates
The actual risks associated with a given exposure result from a complex set of interactions,
which are not understood and cannot be guantitatively estimated with the current state of
knowledge. Examples of such interactions include synergism or antagonism of different
substances, effects on single versus multiple organ systems, and mechanisms of carcinogenesis.
In addition, potential differences in sensitivities of various subpopulations to various
chemicals are poorly understood at this time.
Because there may be small individual uncertainties at each step of the risk assessment process,
these uncertainties may become magnified in the final risk characterization. The final
guantitative estimates of risk may be as much as an order of magnitude different from the actual
risk associated with a given site. In an attempt to minimize the conseguences of uncertainty,
Agency guidance typically relies upon use of conservative estimates of hazards in the absence of
appropriate comprehensive data. The overall result is that risk estimates presented in this
report are more likely to overestimate the actual risks than to underestimate them.
This assessment has been prepared in a manner consistent with that generally used in the
consulting community and Agency guidance at the time it was prepared. It is likely that risk
assessment methods and the data identifying and guantifying the toxicity of chemicals will
improve with time. Conseguently, unsuspected hazards at this site may be identified at a later
date. This assessment was based upon available data, using currently available risk assessment
methodology.
6.3 Ecological Risk Assessment
A four-step process is utilized for assessing site-related ecological risks for a reasonable
maximum exposure scenario. Problem Formulation gualitatively evaluates contaminant release
-------
migration, and fate; identifies COPCs, receptors, exposure pathways, and known ecological
effects of the contaminants; and selects endpoints for further study. Exposure Assessment
evaluates contaminant release, migration, and fate; characterizes exposure pathways and
receptors; and measures or estimates exposure point concentrations. Ecological Effects
Assessment includes literature reviews, field studies, and toxicity tests, linking contaminant
concentrations to effects on ecological receptors. Risk Characterization is the measurement or
estimation of both current and future adverse effects.
The ecological RA for Site 6 began with evaluating the contaminants associated with the site in
conjunction with the site-specific biological species/habitat information. The purpose of this
RA was to determine if past activities at the former pest control shop are adversely impacting
the San Pedro Swamp, the Bayamon River, or the Haystack Hills region.
The COPCs used in the ecological RA included: chlordane, 4,4'-DDD, endosulfan I, endosulfan
sulfate, heptachlor, heptachlor epoxide, arsenic, selenium, lead, and mercury. These COPCs were
selected because they are the only chemicals for which toxicity data is available. The mallard
duck was chosen to represent aguatic birds (surrogate species) at the site since no
toxicological data exists on the specific species found at the site and be use extensive
toxicity testing has been conducted on the mallard duck.
The ecological RA concluded that no potential ecologic risks were present to the surrogate
species, the mallard duck, and therefore, no potential risks were assessed to be present for
local species. Also, risks due to bioaccumulation were not expected.
7.0 REMEDIAL ACTION OBJECTIVES
Remedial action objectives are specific goals to protect human health and the environment; they
specify the COPCs, the exposure routes, receptors, and acceptable contaminant levels for each
exposure route. These objectives are based on available information and standards such as
applicable or relevant and appropriate reguirements (ARARs). At this time, there are no ARARs
established for the cleanup of soil. In the absence of ARARs, chemical-specific To Be
Considered (TBC) criteria were evaluated, instead. A chemical-specific TBC of 500 micrograms
per kilogram for gamma-Chlordane was obtained from the RCRA Corrective Action Levels listed in
40 CFR Part 264.521, Appendix A and Appendix C (Proposed Rule). Chlordane is a mixture of
chlorinated hydrocarbons consisting of isomers of chlordane and closely related compounds and
byproducts. Gamma-chlordane is an isomer of chlordane, so gamma-chlordane makes up a part of
chlordane. Therefore, the chlordane listing can be used for gamma-chlordane. In general, the
chlordane mixture is comprised mostly of the gamma-chlordane isomer. Therefore, gamma-chlordane
is not listed in either Appendix A or Appendix C as gamma-chlordane; gamma-chlordane is listed
as chlordane. Since Site 6 poses no unacceptable risk to human health or the environment and
there are no ARARs established for the cleanup of soil; no action is necessary. Nevertheless,
the Navy prefers to implement a pro-active remedial action. The Navy's decision to implement a
remedy has been based upon the sensitive location of the site which is adjacent to playground
and residential areas. The Navy's remedial action objective for this site is to prevent exposure
to the concentrations of gamma-Chlordane in the soil which are greater than the TBC criteria.
-------
8.0 DESCRIPTION OF ALTERNATIVES
In the process of selecting a response action for Site 6, Remedial Action Alternatives (RAAs)
were developed for the contaminated media at each site. Three RAAs were developed for the soil
at Site 6:
RAA No. 1 - No Action
RAA No. 2 - Capping
• RAA No. 3 - Excavation and Off-Site Incineration
The following subsections briefly describe the RAAs developed. The RI/FS report contains more
detailed information pertaining to each RAA.
• Alternative 1: No Action
Capital Cost: $0
Operation and Maintenance (O&M) Cost: $0
Present Worth Cost: $0
Construction Time: None
CERCLA reguires that the No Action Alternative be considered as a baseline for comparison of
other alternatives. Under the No Action Alternative, no remedial actions would be taken at Site
6 for the remediation of pesticide-contaminated soil. There would be no reduction in the
toxicity, mobility, or volume of contaminants. There are no costs associated with the
implementation of this alternative.
• Alternative 2: Capping
Capital Cost: $43,000
O&M Cost: $1,000 per year
Present Worth Cost: $74,000 (assuming cap replacement at Year 20)
Construction Time: One year or less
The Capping Alternative includes the installation of an asphalt cap (4 inches thick) over the
area of approximately 2,190 sguare feet of surface contaminated above the TBC criteria. Soil
excavation will not be included. The cap will reduce the potential for dermal exposure to the
pesticide-contaminated soil within the site. The use of caps and their reliability has been
proven. The life expectancy of an asphalt cap is approximately 20 to 25 years with routine
maintenance. This alternative could be easily implemented since the Site 6 area is flat and
open. Materials and eguipment should be easily obtained. Long-term groundwater monitoring will
be easily accomplished due to the existing monitoring wells at the site.
• Alternative 3: Off-Site Incineration
Capital Cost: $580,000
O&M Cost: $0
Present Worth Cost: $580,000
Construction Time: One year or loss
The Off-Site Incineration Alternative includes the excavation, removal, and off-site
incineration of soil with pesticide concentrations exceeding the remediation level. The
approximate guantity of soil to be removed is 250 cubic yards. This volume includes soil with
concentrations of gamma-Chlordane greater than 500 micrograms per kilogram. The maximum depth
of excavation will be three feet. The excavation will be backfilled with certified clean soil
-------
and revegetated. The contaminated material will be loaded into approved containers and
transported by barge to the Port of Texas under a hazardous waste manifest. The soil will then
be trucked to a licensed incineration facility, tentatively identified in Morgan City,
Louisiana. All ash remaining after incineration will be disposed of by the incineration
facility. There are currently no licensed facilities in Puerto Rico capable of receiving
pesticide-laden wastes.
9.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES
During the detailed evaluation of RAA, each alternative is assessed against nine evaluation
criteria, namely: Overall Protection of Human Health and the Environment; Compliance with
ARARs; Long-Term Effectiveness and Permanence; Reduction of Toxicity, Mobility, or Volume
through Treatment; Short-Term Effectiveness; Implementability; Cost; USEPA/Commonwealth
Acceptance; and, Community Acceptance.
A comparative analysis of the RAAs was based on nine evaluation criteria, and how well the RAAs
met the Navy's remedial action objective of preventing exposure to gamma-Chlordane
concentrations above the TBC criteria of 500 micrograms per kilogram. The evaluation criteria
are summarized below.
• Overall Protection of Human Health and the Environment - addresses whether or not an
alternative provides adeguate protection and describes how risks posed through each
pathway are eliminated, reduced, or controlled through treatment, engineering or
institutional controls.
• Compliance with ARARs - addresses whether or not an alternative will meet the
applicable or relevant and appropriate reguirements (ARARs), criteria to-be-
considered (TBCs), and other federal and commonwealth environmental statutes,
and/or provide grounds for invoking a waiver.
• Long-Term Effectiveness and Permanence - refers to the magnitude of residual risk
and the ability of an alternative to maintain reliable protection of human health
and the environment over time, once cleanup goals have been met.
• Reduction of Toxicity, Mobility, or Volume Through Treatment - refers to the
anticipated performance of the treatment options that may be employed within an
alternative.
• Short-Term Effectiveness - refers to the speed with which the alternative achieves
protection, as well as the remedy's potential to create adverse impacts on human
health and the environment that may occur during the construction and implementation
period of the remedy until the cleanup goals are achieved.
• Implementability - refers to the technical and administrative feasibility of an
alternative, including the availability of materials and services reguired to
implement the chosen solution.
• Cost - includes capital and operation and maintenance costs. For comparative
purposes, present worth values are provided.
• USEPA/Commonwealth Acceptance - Indicates whether, based on its review of the RI/FS
reports and Proposed Plan, the Commonwealth concurs, opposes, or has no comment on
the preferred alternative. This criterion is addressed in this ROD based on the
comments that have been received on the RI/FS report and Proposed Plan.
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• Community Acceptance - Evaluates the issues and concerns the public may have
regarding each of the alternatives. This criterion is addressed in this ROD based
on the comments that have been received on the RI/FS report and the Proposed Plan.
9.1 Overall Protection of Human Health and the Environment
All alternatives are protective of human health and the environment. Based on the risk
assessment results, the no action alternative is protective of human health and the environment
because there is no unacceptable risk at the site from former practices.
9.2 Compliance with ARARs
As there are no ARARs established for the cleanup of soil that must be complied with, this
evaluation criteria is not applicable. However, in the absence of ARARs, the Navy will use the
TBC criteria to delineate areas of contamination. Alternative 1 does not prevent exposure to
soil exceeding the TBC criteria. Alternatives 2 and 3 will prevent exposure to soil exceeding
TBCs.
9.3 Long-Term Effectiveness and Permanence
The no action alternative may not be effective in the long term and has no indications of
permanence. With proper maintenance, Alternative 2 - Installation of an Impermeable Cap, would
be effective and permanent in the long term. Alternative 3, Off-Site Incineration, would also
be effective and permanent in the long term.
9.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
Alternative 1 would not reduce the toxicity, mobility, or volume of known contamination.
Alternative 2 would reduce the mobility, but not the toxicity or volume of known contamination.
Alternative 3 would reduce the toxicity, mobility, and volume of the contaminated soil.
9.5 Short-Term Effectiveness
Alternatives 2 and 3 are effective in the short-term.
9.6 Implementability
All three alternatives can be easily implemented.
9.7 Cost
Alternative 1 can be implemented at negligible costs. Costs for Alternative 2 were estimated to
be $42,723 (estimated in 1994) and Alternative 3 at $582,000 (estimated in 1994).
9.8 USEPA/Commonwealth Acceptance
By signing this ROD, PREQB, and USEPA have accepted the selected remedy for Site 6.
9.9 Community Acceptance
No comments were received from the public during the Public Comment Period or during the Public
Awareness Session.
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10 . 0 SEIiECTED REMEDY
This section of the ROD presents the selected remedy for Site 6. A description of the selected
remedy is presented along with the estimated costs to implement the remedy. In addition, the
remediation levels to be attained at the conclusion of the remedy are discussed.
10.1 Remedy Description
Based upon an evaluation of the various alternatives, the Navy has selected a variation of
Alternative 2 -Capping as the choice for the Site 6 remedy. The Navy's remedy is to place one
rectangular asphalt cap of 11,000 sguare feet minimum that will cover the two areas above the
TBC criteria, their immediate surroundings, and a portion of the low, wet grassy area to the
northeast of the site. A plan view of this alternative is shown on Figure 4. The capital cost
of this remedy is approximately $215,000 in 1994 dollars.
This cap was selected because it eliminates potential exposure to the soils that may have
limited residual pesticide contamination in the vicinity of the Former Pest Control Shop.
Although the RA indicated that the site poses no unacceptable risks, and that no action was
needed, capping was nevertheless selected to reassure the public by limiting public exposure
because of the site's proximity to the playground/picnic and family housing areas.
10.2 Estimated Costs
The following costs are estimated for Site 6:
Capital Cost: $215,000
Annual O&M: $1,000 per year
NPW: $246,000 (assuming cap replacement at Year 20)
11.0 STATUTORY DETERMINATIONS
A selected remedy should satisfy the statutory reguirements of CERCLA Section 121 which include:
(1) protect human health and the environment; (2) comply with ARARs; (3) achieve
cost-effectiveness; (4) utilize permanent solutions and alternative treatment technologies or
resource recovery technologies to the maximum extent practicable; and (5) satisfy the
preference for treatment that reduces toxicity, mobility, or volume as a principal element, or
provide an explanation as to why this preference is not satisfied. The evaluation of how the
selected remedy, an asphalt cap over Site 6, satisfies these reguirements is presented below.
11.1 Protection of Human Health and the Environment
Because there is no unacceptable risk at the site due to former or current practices, protection
of human health and the environment is not necessary. As a pro-active measure to reassure the
public, the Navy has chosen to implement an asphalt cap over the areas where pesticides were
detected above the TBC criteria. The cap will eliminate the potential for any contact, human or
environmental, with any remaining minimal pesticide contaminated soils and; therefore, is
protective of human health and the environment.
11.2 Compliance with Applicable or Relevant and Appropriate Reguirements
There are no ARARs established for the cleanup of soil. In the absence of ARARs, the Navy
elected to use TBC criteria to delineate areas of soil contamination. Alternative 2, an asphalt
cap over Site 6, prevents exposure to soils containing pesticides above the TBC criteria.
-------
11.3 Cost-Effectiveness
The selected remedy affords overall effectiveness proportional to its costs. This alternative
was the most cost effective of the active alternatives.
11.4 Utilization of Permanent Solutions and Alternative Treatment Technologies
The selected remedy represents a permanent solution with respect to the principal threats posed
by soil contamination. Treatment has not been selected because the RA dictated that no action
was necessary.
11.5 Preference for Treatment that Reduces Toxicity, Mobility, or Volume as a Principal
Element
Treatment of soil contaminated above the TBC criteria has not been retained as a principal
element of the selected remedy. Treatment has not been selected because the RA dictated that no
action was necessary. As a pro-active measure to reassure station residents, the Navy has
elected to install a permanent asphalt cap over areas of contaminated soil to eliminate all
contact with any remaining minimal pesticide contaminated soil.
12.0 RESPONSIVENESS SUMMARY
12 .1 Overview
A Public Comment Period was held from May 15, 1996 through June 15, 1996. A Public Awareness
Session, in lieu of a public meeting, was held on June 7, 1996. These public participation
events were announced in English and Spanish to military and local personnel. No written or
oral comments were received from the public on the selected remedy for Site 6.
12.2 Background on Community Involvement
A record review of the NSGA Sabana Seca files indicates that the community involvement centers
mainly on a social nature, including the community outreach programs and Station/community
clubs.
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Community relations activities to date are summarized below:
• Prepared a Community Relations Plan for all sites at the Station.
• Prepared a Draft Information/Photo Album, June 7, 1996, for all sites at the
Station.
• Prepared a Draft Site Brochure, June 1993, for all sites at the Station.
• Established two information repositories at a local library and the Station's
library.
• Established the Administrative Record for all of the sites at the Station.
• Held Technical Review Committee meetings to review the status of the remedial
activities on the Station.
• Released a Proposed Plan in English and Spanish for public review in repositories,
May 1996.
• Released a public notice in English and Spanish announcing a public comment
period and reguesting attendance at the Public Awareness Session.
• Held a Public Awareness Session on June 7, 1996, to solicit comments and provide
information to the community.
12.3 Summary of Comments Received During the Public Comment Period and Agency Responses
No written or oral comments were received from the public during the Public Comment Period.
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TABIiE 1
CHEMICALS OF POTENTIAL CONCERN
FOR THE HUMAN HEALTH RISK ASSESSMENT
COPC (mg/kg)
Surface
Soil
Surface
Water
Sediment
VOCs:
Toluene
SVOCs:
bis (2-ethylhexyl)phthalate
Di-n-butylphthaiate
Di-n-octylphthaiate
Phenol
3 and 4-Methylphenol
PESTICIDES:
alpha-Chlordane
gamma-Chlordane
Endosulfan I
Endosulfan Sulfate
Heptachlor
Heptachlor Epoxide
4,4-DDD
METALS AND CYANIDE:
Aluminum
Antimony
Arsenic
Manganese
Zinc
Cyanide
1.02E-02
7.63E-01
2.20E-01
2.90E-01
5.75E-01
1.58E+00
7.80E-03
4.80E-03
2.23E+04
1.24E+01
1.10E-01
5.00E-02
1.30E-01
5.67E-02
4.10E-03
1.76E-01
4.68E-02
2.30E-03
1.98E+00
2.67E+00
6.10E-02
3.50E-02
1.80E-02
1.40E-01
6.10E+00
X = Indicates a COPC for the specified media.
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TABLE 2
EXPOSURE PATHWAYS
Potentially
Exposed
Population
Noncarcinogens
Adult
Adult
Children
Future Recreational
Adult
Children
Future Commercial
Adult
Ingestion
Dermal
Dermal
Dermal
Dermal
El Data(d)
El Data(d)
El Data(d)
El Data(d)
El Data(d)
El Data(d)
El Data(d)
El Data(d)
El Data(d)
El Data(d)
El Data(d)
ABS AF ET EF ED
(unitless) (mg/cm2) (hr/day) (events/ (yrs)
yr)
70
15
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TABLE 2
EXPOSURE PATHWAYS
BW
(kg)
Dermal El Data(d)
El Data(d)
(a) Ingestion units for water Ingestion are L\day and for soil Ingestion are rag/day.
(b) Conversation Factor.
(c) Noncarcinogenic averaging time, carcinogenic average time. AT converted to days for calculations. 70 years (25,550 days) for carcinogens, 30 years (10,950) for noncarcinogens for adults, 6 years
(2,190 days) for noncarcinogenic for children.
(d) El=based on monitoring data from the Environmental Investigation.
(e) This value is chemical-specific.
(f) Surface areas 2b% of the 95th percentile of the total skin surface area for the appropriate age group.
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TABLE 3
TOXICITY VALUES - RFD
Summary Table of Reference Doses and Concentrations
Site 6, NSGA Sabana Seca, Puerto Rico
Constituent
Toluene
Bis(2-ethylhexyl)phthalate
Di-n-butylphthalate
Di-n-octylphthalate
Phenol
3-and 4-Methylphenol
a-Chlordane*
g-Chlordane*
Endosulfan
Endosulfan sulfate**
Heptachlor
Heptachlor Epoxide
4,4-DDD
Aluminum
Antimony
Arsenic
Manganese
Oral
Chronic
RfD
(mg/kg-day)
Chronic
Uncert.
Factor
Mod.
Factor
Volatile Organic Compounds
0.2 a 1,000 1
Semivolatile Organic Compounds
0.02 a
0.1 a
0.02 b
0.6 a
0.05 a
0.00006 a
0.00006 a
0.006 b
0.006 b
0.0005 a
0.000013 a
NA
1,000
1,000
1,000
100
1,000
1,000
1,000
NA
NA
300
1,000
NA
NA
1,000
1
1
UR
1
1
Pesticides
1
1
NA
NA
1
1
NA
Metals and Cyanide
NA
1
Confi-
dence
Medium
Medium
Low
UR
Low
Medium
Oral
Subchronic
RfD
(mg/kg-day)
2.0 b
0.02 b
1.0 b
0.02 b
0.6 b
0.5 b
2.9 c
0.0004 a
0.0003 a
0.005 a
NA
1,000
3
1
NA
1
1
1
NA
Low
Medium
Varied
NA
0.0004 b
0.0003 b
0.005 b
Target
Organ
Liver,
kidneys, and
CNS
Liver
Entire body
Kidneys, liver
Kidneys
CNS
1
1
NA
NA
1
1
NA
Low
Low
NA
NA
Low
Low
NA
0.00006 b
0.00006 b
0.006 b
0.006 b
0.0005 b
0.000013 b
NA
Liver
Liver
Kidneys
NA
Liver
Liver
Liver
NA
Longevity,
blood glucose
Hyper-
pigmentation
CNS effects
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TABLE 3
TOXICITY VALUES - RFD
Summary Table of Reference Doses and Concentrations
Site 6, NSGA Sabana Seca, Puerto Rico
Notes:
a -
b -
c -
NA -
UR -
CNS -
Constituent
Mercury
Zinc
Cyanide
Oral
Chronic
RfD
(mg/kg-day)
0.0003 b
0.3 a
0.02 a
Chronic
Uncert .
Factor
1,000
3
100
Mod.
Factor
NA
1
5
Confi-
dence
NA
Medium
Medium
Oral
Sub chronic
RfD
(mg/kg-day)
0.0003 b
0.3 b
0.02 b
Target
Organ
Kidneys
Blood
Kidneys
IRIS (EPA, 1994).
HEAST, FY1992 (EPA, 1992b).
EPA Region III RBC (6/10/93) (EPA, 1993b).
Toxicity values were unavailable for alpha-and gamma-chlordane; chlordane values were used for evaluation.
Toxicity values were unavailable for endosulfan sulfate; endosulfan values were used for evaluation.
Not available.
Under review.
Central nervous system.
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TABIiE 4
TOXICITY VALUES - SLOPE FACTORS
Summary Table of Carcinogenic Slope Factors
Site 6, NSGA Sabana Seca, Puerto Rico
Constituent
Oral
Slope Factor
(mg/kg-day)
Unit Risk
C g/L)
Toluene
Volatile Organic Compounds
NA NA
Semivolatile Organic Compounds
Bis (2-ethylhexyl)phthalate
Di-n-butylphthalate
Di-n-octylphthalate
Phenol
3- and 4-Methylphenol
0.014 a
NA
UR
NA
NA
Pesticides
0.0000004a
NA
UR
NA
NA
Class
B2
D
NA
D
C
a-Chlordane*
g-Chlordane*
Endosulfan
Endosulfan sulfate
Heptachlor
Heptachlor epoxide
4,4-DDD
Aluminum
Antimony
Arsenic
Manganese
Mercury
Zinc
Cyanide
1.3 a
1.3 a
NA
NA
4.5 a
9.1 a
0.24 a
Metals and Cyanide
NA
NA
1.75 b
NA
NA
NA
NA
0.000037 a
0.000037 a
NA
NA
0.00013 a
0.00026 a
0.0000069 a
B2
B2
NA
NA
B2
B2
B2
NA
NA
-NA
NA
NA
NA
NA
NA
D
A
0
D
D
0
Notes:
a -
b -
NA -
UR -
Class:
IRIS (EPA, 1994).
EPA Region III Risk-Based concentration Table (EPA, 1993b).
Toxicity values were unavailable for alpha- and gamma-chlordane;
used for evaluation.
Not available.
Under review.
Carcinogenic weight of evidence classification.
chlordane values were
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TABIiE 5
SUMMARY OF PATHWAY - SPECIFIC RISKS
Summary Table of Carcinogenic Risks
Site 6, NSGA Sabana Seca, Puerto Rico
Pathways
Media
Soil
Surface Water
Sediment
Notes:
NA - Not applicable.
Receptors
Adults
Children
Pre-adolescent
Pre-adolescent
nc
3.
2.
Residential
jestion Dermal
Contact
, 84E-05 NA
, 69E-05 NA
—
Recreational
Ingestion Dermal
Contact
5.71E-06
4.00E-06
--
NA
NA
7.61E-09
NA
Commercial
Ingestion
4.30E-06
--
--
Summary Table of Noncarcinogenic Hazards
Site 6, NSGA Sabana Seca, Puerto Rico
Media
Soil
Surface Water
Sediment
Receptors
Adults
Children
Pre-adolescent
Pre-adolescent
Pathways
Residential Recreational
Ingestion Dermal Ingestion Dermal
Contact Contact
1.17E-01
9.93E-01
NA
NA
1.74E-02
1.48E-01
NA
NA
2.44E-03
NA
Commercial
Ingestion
4.18E-02
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FIGURES
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