declaration - us environmental protection agency · pdf fileps prp response under state rp ......

/ 5.7Officer NSGA Sabana Seca) Date

( / I y 7ntal Quality Board) Date

Sig • ature (Commandinl

rator, USZ A Region II)-.70 Std. f

Date

vi

OCT-01-1997 15:27 EPA 212 637 3256 P.03/03

DECLARATION

Site lt naiinilleOSAiska

' Site 1 - South Stone Road Disposal AreaSite 3 - North Stone Road Disposal AreaNaval Security Group Activity, Sabana Seca, Puerto Rico

Statement of Basis and Puriose

This decision document presents the selected remedy for Site 1 and Site 3 at the Naval Security GroupActivity (NSGA) Sabana Seca. The remedy was chosen in accordance with the ComprehensiveEnvironmental Response, Compensation, and Liability Act of 1980 (CERCLA), as amended by theSuperfund Amendments and Reauthorization Act (SARA), and, to the extent practicable, the National Oiland Hazardous Substances Pollution Contingency Plan (NCP). This decision is based on the administrativerecord file for Site 1, the South Stone Road Disposal Area and Site 3, the North Stone Road Disposal Area.

Description of Selected . Remedy

The selected remedy for Site 1 and Site 3 is no action.

DeelarationStatemeft

This Record of Decision (ROD) documents that no action is necessary at Sites 1 and 3 to ensure protectionof human health and the environment. Because this remedy will not result in hazardous substancesremaining on site above health-based levels, the five-year review will not apply to this action.

In lieu of a Final Close Out Report, this ROD also documents that the U.S Navy has completed allconstruction activities for all sites at the NSGA Sabana Seca Site in accordance with Close Out Proceduresfor National Priorities List Sites (OSWER Directive 9320.2-09). No action has been determined to benecessary for Sites 1, 2, 3, and 4; the Navy has cleaned up Sites 5 and 6; and Site 7 will be addressed by theMunicipality of Toa Baja, the party responsible for Site 7 contamination. This decision documents that theNavy, U.S. Environmental Protection Agency (USEPA) and Puerto Rico Environmental Quali ty Board(PREQB) have determined that remedial actions for this site have been successfully implemented and nofurther response actions are necessary. Therefore, the site now qualifies for inclusion on the ConstructionCompletion List. The PREQB conducted an inspection on May 9, 1997; and, the USEPA conducted aninspection on July 17, 1997, and both agencies concur that all remedial action has been successfully executedby the Navy.

TOTAL P.03

C /ezSignal re (Chairman, PR Enviio

re (Commanding11.111.11IP11111.UML11

. Iona ay' oard)

eca)

Signature (Regio

OCT-01-1997 15:26

EPA 212 637 3256 P.02/03

•

DECLARATION

site Name and Location,

Site 2 - Bunker 607 Disposal AreaSite 4 - Pistol Range Disposal AreaNaval Security Group Activity, Sabana Seca, Puerto Rico

Statements& Basis and Purpose

This decision document presents the selected remedy for Site 2 and Site 4 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). Thisdecision is based on the administrative record file for Site 2, the Bunker 607 Disposal Area and Site 4, the Pistol RangeDisposal Area.

Description of Selected Remedy


peclaration Statemeni


In lieu of a Final Close Out Report, this ROD also documents that the U.S. Navy has completed allconstruction activities for all sites at the NSGA Sabana Seca Site in accordance with Close Out Proceduresfor National Priorities List Sites (OSWER Directive 9320.2-09). No action has been determined to benecessary for Sites 1, 2, 3, and 4; the Navy has cleaned up Sites 5 and 6; and Site 7 will be addressed by theMunicipality of Toa Baja, the party responsible for Site 7 contamination. This decision documents that theNavy, U.S. Environmental Protection Agency (USEPA) and Puerto Rico Environmental Quality Board(PREQB) have determined that remedial actions for this site have been successfully implemented and nofurther response actions are necessary. Therefore, the site now qualifies for inclusion on the ConstructionCompletion List, The PREQB conducted an inspection on May 9, 1997; and, the USEPA conducted aninspection on July 17, 1997, and both agencies concur that all remedial action has been successfully executedby the Navy.

/5 5G-72 27 Date

)1,3Date

vii

Site Name: 6R.84 N I S

Congressional District:

1- 4uk&L60_

ABCGHIJ.

O

V

Military RelatedOtherLagoons

• Radioactive SiteMines/TailingsWaterways/Creeks/RiversWells

AbandonedChemical Plant ,City ContaminationGroundwaterHousing Area/FarmIndustrial WasteInorganic WasteLandfillManufacturing Plânt

kci/0712, .1ka01,4 0/-61-4-f/

NFL CONSTRUCTION COMPLETION SITE INFORMATION

EPA ID: fg417 Oda-13 g

State: R Region: a

Construction Completion Date:

please circle appropriate Document Type Code:Code

Description .

COR

Close Out Report (COR)DEL

DeletionICOR

Interim CORLAR

Limited Action RODNo Action ROD

NOID

Notice Of Intent To DeleteNONE

No document availablePCOR

Prelim.inary COR

LTRA 1 : Yes

No

Please circle appropriate Site Lead 2 Code as indicated in CERCLIS: Code Description

F

Fund FinancedFE

PRP Response under Fed.Federal FacilityMixed Responsible' Party

PS

PRP Response under StateRP

Responsible PartyS

State, fund financedSE

State EnforcementSN -State, no fund moneySR

State & Responsible PartyTR

Tribal Lead

Please circle appropriate Site Type(s) Code(s) as indicated in CERCLIS: Code Description ,

Long Term Response Actions (LTRA) are undertaken for the purpose of restoring groundwater.These actions may require several years of onsite activity before cleanup levels are achieved.

"Lead" represents the party responsible for final operable unit remedial action activities;if no remedial work was performed, "lead" represents party responsible for other actions.

- •Please circle appropriate Clean-up Activity/Technology Code:

On-Site Containment Code/DescriptionBF - BackfillingCP - Surface Capping Only (cement, clay, low permeability cover)CS - Surface Capping w/ slurry wall and coverCV - Soil coverDG - Excavation and on-site containmentEN - Encapsulation or overpacking w/ final on-site disposalSD ,-,Surface drainage control- dikes, berms, ditches, diversionary measuresSL - Solidification/stabilization: vitrification, immobilization, fixationST - Drumg , staged onlySU - - Slurry wall .

Off-Site Containment Code/DescriptionDO - Excavation and final removal to off-site landfillEC - Encapsulation or overpacking with final off-site disposal

- Removal to off-site locations- Final removal to off-site landfill ,

. On-Site Treatment Code/DescriptionAE - Soil aeration technologiesAI Air stripping technologiesBO - Biodegradation and bioremediation treatmentDC - DechlorinationIF - In situ flushingIN - Incineration and on-site disposal of residualX - Incineration w/ off-site disposal of residual

jlpn - Leachate treatmentLF - Landfill gas extraction system; Venting; Gas CollectionNA - Natural attenuationNU - pH neutralization, other neutralization methodsPO - Pump and treat, final on-site discharge or reinjectionPX - Pump and treat, final off-site discharge or reinjectionRC - Rempval to off-site locations after on-site treatmentSV - Soil vapor extractionSW - Soil washingTD - Thermal desorptionTH - Thermal treatment w/on-site placement of residuals'TM - Thermal treatment w/off-site placement of residuals

Off-Site Treatment Codes/DescriptionID - Incineration and disposal

- Removal for off-site treatment and disposal

Other Site Treatment Codes/DescriptionIC - Institutional controls)-X, - Innovative technologiesce...9- No clean-up necessaryRA - Referred to another authority.RR - Permanent relocation of residents'SM L- Surface water monitoringWA - Permanent water supply providedWL 7 Construction of wells other than monitoring wellsWM - Groundwater monitoring

Conments: )NMI/

2

FINAL

RECORD OF DECISIONSITE 1- SOUTH STONE ROAD DISPOSAL AREASITE 3 - NORTH STONE ROAD DISPOSAL AREA

NAVAL SECURITY GROUP ACTIVITYSABANA SECA, PUERTO RICO

CONTRACT TASK ORDER 0047

SEPTEMBER 3, 1997

Prepared For:

DEPARTMENT OF THE NAVYATLANTIC DIVISION

NAVAL FACILITIES ENGINEERING COMMANDNorfolk Virginia

Under the:

LANTDIV CLEAN ProgramContract N62470-89-D-4814

Prepared By:

BAKER ENVIRONMENTAL, INC.Coraopolis, Pennsylvania

TABLE OF CONTENTS

Rag_e

LIST OF ACRONYMS AND ABBREVIATIONS

DECLARATION vii

1.0 SITE NAME, LOCATION, AND DESCRIPTION 1

2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 2

2.1 Site History 22.1.1 History - Site 1 32.1.2 History - Site 2 32.1.3 History - Site 3 32.1.4 History - Site 4 42.1.5 History - Site 5 42.1.6 History - Site 62.1.7 History - Site 7

2.2 Previous Investigations/Enforcement Activities 2.2.1 Previous Investigations 2.2.2 Enforcement Activities

2.3 Site Inspections/Remedial Investigation/Leachate Diversion-FeasibilityStudy 2.3.1 Site Inspections - Sites 2 and 4 - (OU-1) 2.3.2 Remedial Investigation - Site 6 - (OU-2) 2.3.3 Leachate Diversion-Feasibility Study - Site 7

2.4 ROD Findings 2.4.1 Sites 2 and 4 - (OU-1) 2.4.2 Site 6 - (OU-2)

2.5 Remedial Design/Remedial Action - Site 6 - (OU-2) 2.5.1 Design Activities 2.5.2 Remedial Construction Activities 2.5.3 Summary of Operations and Maintenance

2.6 Community Relations Activities

2.7 Site Close Out

2.8 Five-Year Review

3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION 14

4.0 SCOPE AND ROLE OF THE RESPONSE ACTION 16

5.0 SUMMARY OF SITE CHARACTERISTICS 165.1 Initial SI Data Results 16

5.1.1 Soil Contamination - Site 1 165.1.2 Soil Contamination - Site 3 175.1.3 Groundwater Contamination - Site 1 175.1.4 Groundwater Contamination- Site 3 17

5.2 ESI Data Results 18

5 5

778

899

1011111111111213131314

ii

4

TABLE OF CONTENTS(Continued)

Page

5.2.1 Background Soil Contamination - Sites 1 and 3 185.2.2 Background Groundwater Contamination - Sites 1 and 3 18

6.0 SUMMARY OF SITE RISKS 186.1 Initial SI Qualitative Risk Assessment 19

6.1.1 Qualitative RA - Site 1 196.1.2 Qualitative RA - Site 3

19

6.2 ESI Quantitative Risk Assessment

206.3 Uncertainty Analysis 22

6.3.1 Analytical Data and Selection of COPCs 236.3.2 Exposure Assessment

24

6.3.3 Toxicity Assessment

256.3.4 Risk Characterization

26

6.4 Ecological Risk Assessment

26

7.0 DESCRIPTION OF THE "NO ACTION" ALTERNATIVE 26

8.0 RESPONSIVENESS SUMMARY 27

8.1 Overview 27

8.2

Community Preferences 27

8.3

Summary of Comments Received During the Public Comment Period andAgency Responses 28

9.0 BIBLIOGRAPHY 28

TABLES

1 Contaminants of Potential Concern for the Human Health Risk Assessment - Surface SoilData Summary - Range of Inorganic Positive Detections for Background

2 Contaminants of Potential Concern for the Human Health Risk Assessment - GroundwaterData Summary

3 Summary of Incremental Lifetime Cancer Risks4 Toxicity Values - RfD and Slope Factors5 Summary of Hazard Indices6 Exposure Pathways7 Summary of Uncertainties in the Results of the Human Health Risk Assessment

FIGURES

1 Vicinity Map2 Site Plan - Site 13 Site Plan - Site 34 Installation Restoration Site Locations

ARAR

CERCLACOPCCPRCCRPCSF

DOD

ESI

FFAFS

FITHQ

IASILCRIR

µg/kglig/LMCLmg/kg

NCPNPLNSGA

O&MOU

PREQB

RARABRAGSRBCRCRARDRfDRIROD

SARASI


applicable or relevant and appropriate requirements

Comprehensive Environmental Response, Compensation and Liability Actcontaminants of potential concernCaribbean Primate Research CenterCommunity Relations Plancancer slope factor

Department of Defense

expanded site inspection

Federal Facilities Agreementfeasibility study

hazard indexhazard quotient

Initial Assessment Studyincremental lifetime cancer riskInstallation Restoration

micrograms per kilogrammicrograms per literFederal Maximum Contaminant Levelmilligrams per kilogram

National. Oil and Hazardous Substances Pollution Contingency PlanNational Priorities ListNaval Security Group Activity

operations and maintenanceoperable unit

Puerto Rico Environmental Quality Board

risk assessmentRestoration Advisory BoardRisk Assessment Guidance for Superfundrisk-based criteria ,Resource Conservation and Recovery Actremedial designreference doseremedial investigationrecord of decision

Superfund Amendment and Reauthorization Actsite inspection

iv

LIST OF ACRONYMS AND ABBREVIATIONS(Continued)

TALTBCTCL

UCLUSEPA

VOCs

Target Analyte ListTo Be Considered CriteriaTarget Compound List

upper confidence limitUnited States Environmental Protection Agency

volatile organic compounds

ture (Command' GA Sabana ca)

DECLARATION

Site Name and Location

Site 1 - South Stone Road Disposal AreaSite 3 - North Stone Road Disposal AreaNaval Security Group Activity, Sabana Seca, Puerto Rico

Statement of Basis and Purpose

This decision document presents the selected remedy for Site 1 and Site 3 at the Naval Security GroupActivity (NSGA) Sabana Seca. The remedy was chosen in accordance with the ComprehensiveEnvironmental Response, Compensation, and Liability Act of 1980 (CERCLA), as amended by theSuperfund Amendments and Reauthorization Act (SARA), and, to the extent practicable, the National Oiland Hazardous Substances Pollution Contingency Plan (NCP). This decision is based on the administrativerecord file for Site 1, the South Stone Road Disposal Area and Site 3, the North Stone Road Disposal Area.



Declaration Statement


In lieu of a Final Close Out Report, this ROD also documents that the U.S. Navy has completed allconstruction activities for all sites at the NSGA Sabana Seca Site in accordance with Close Out Proceduresfor National Priorities List Sites (OSWER Directive 9320.2-09). No action has been determined to benecessary for Sites 1, 2, 3, and 4; the Navy has cleaned up Sites 5 and 6; and Site 7 will be addressed by theMunicipality of Toa Baja, the party responsible for Site 7 contamination. This decision documents that theNavy, U.S. Environmental Protection Agency (USEPA) and Puerto Rico Environmental Quality Board(PREQB) have determined that remedial actions for this site have been successfully implemented and nofurther response actions are necessary. Therefore, the site now qualifies for inclusion on the ConstructionCompletion List. The PREQB conducted an inspection on May 9, 1997; and, the USEPA conducted aninspection on July 17, 1997, and both agencies concur that all remedial action has been successfully executedby the Navy.

/ / 9 9 7

Signa

Date

/S—t3 //19 Board) Date

•Signature (Real Admi tor, USEP Region II)

3a ell?). fillDate

vi

1.0 SITE NAME, LOCATION, AND DESCRIPTION

This Record of Decision (ROD) is for Operable Unit (OU) -3 Site 1, the South Stone Road Disposal

Area, and Site 3, the North Stone Road Disposal Area, both of which are located in the south tract

of the Naval Security Group Activity (NSGA) Sabana Seca. Other parts of the NSGA Sabana Seca

site are being addressed in separate actions. OU-1 is for Sites 2 and 4, and OU-2 is for Site 6.

The 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 Naval Base consists of a North and

South Tract together occupying over 2,200 acres of land. NSGA Sabana Seca is a site being

investigated for environmental contamination under CERCLA and is included on United States

Environmental Protection Agency (USEPA's) National Priority List (NPL).

NSGA Sabana Seca was originally a pineapple and grapefruit plantation known as the Stephenson

Place. The plantation was procured by the U.S. Navy during World War II. After the war, the

property was turned over to the U.S. Army. In 1951, the Navy again assumed control and in 1952,

established the U.S. Naval Radio Station, Sabana Seca. In 1971, NSGA Sabana Seca was

established as an independent shore activity of the Navy. The facility has been operated as a

communications center continuously by the Navy since 1971.

Figure 1 presents a map of the south . tract and the locations of Sites 1 and 3 within the south tract.

Site 1 is located within the western portion of the south tract approximately 2,000 feet southwest of

the intersection of Stone and Bataan Roads. Site 1 is located on the south side of Stone Road

adjacent and north of the Caribbean Primate Research Center (CPRC). Site 3 is located in the north-

central portion of the south tract. Site 3 is north and adjacent to Stone Road, between Redman Road

and Bataan Road. 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 Bayamon and Toa Baja Municipal

Landfills and the U.S. Department of Health and Human Services Research Facility.

The water table of the groundwater aquifer supply NSGA Sabana Seca is located approximately 50

to 70 feet below ground surface (bgs). The south tract of NSGA Sabana Seca is serviced by two

deep Base supply wells, at depths of 130 feet and 140 feet bgs, and are located in Building 10 and

22, east of the enlisted housing area and north of the officer housing area. The Base water supply

wells are located approximately 4,600 feet east of Site 1 and 3,000 feet southeast of Site 3. The

groundwater aquifer has not been impacted by on-site activity.

Figure 2 presents a site plan of Site 1 and shows the adjacent property uses. Site 1 covers an area

of approximately 2 acres and is bordered on the south and west sides by the CPRC. The Initial

Assessment Study (IAS) originally estimated the site to cover 10 acres. The areas to the north and

east of Site 1 are undeveloped and heavily vegetated. Stone Road borders the north side of Site 1.

The site is currently undeveloped and overgrown with vegetation.

Figure 3 presents a site plan of Site 3 and shows the adjacent property uses. Site 3 covers an area of

approximately 11 acres. The IAS originally estimated the site to cover 4.5 acres. The site is

bordered by Redman, Stone, and Bataan Roads on the west, south, and east sides, respectively. The

area around Site 3 is undeveloped and heavily vegetated. The Base's perimeter fence borders the

east side of the site. The site is currently overgrown with vegetation.

The topography at Sites 1 and 3 is relatively flat and heavily vegetated. There is no surface water

present at Sites 1 or 3.

2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES

2.1 Site History

An IAS conducted in 1984 identified and assessed sites posing a potential threat to human health or.

the environment. The IAS identified seven sites:

Site 1 - South Stone Road Disposal Area

Site 2 - Bunker 607 Disposal Area

Site 3 - North Stone Road Disposal Area

Site 4 - Pistol Range Disposal Area

Site 5 - Wenger Road Disposal Area

Site 6 - Former Pest Control Shop

Site 7 - Leachate Ponding Area

2

The locations of these sites are shown on Figure 4.

2.1.1 History - Site 1

According to the LAS report, Site 1 was the Base's landfill in operation from 1951 to 1960. During

that time, an estimated 3,300 tons of solid waste, including residential waste, construction debris,

scrap metal, appliances, paint cans, and tree clippings were disposed at the site. The Public Works

Department collected solid waste twice a week using a dump truck, and deposited the solid waste

at Site 1. The solid waste was dumped directly onto the ground and left as mounds. Trenching and

daily cover were not employed as part of the disposal operations. No hazardous wastes were

reported to have been disposed at Site 1. Site 1 has remained inactive. The Navy has not removed

any wastes from Site 1. CERCLA investigation has determined that no action is necessary at this

site.


According to the IAS report, Bunker 607 was intermittently used by the Public Works Department

for materials storage from the 1960s to 1979. In 1979, the Public Works Grounds Maintenance

Division was ordered to clean out the bunker. Reportedly, approximately 500 one-gallon cans of

old paint intended to be used for the on-Base housing were disposed in the vicinity of Bunker 607.

CERCLA investigation has determined that no action is necessary at this site:


According to the IAS report, Site 3 was the Base's landfill in operation from 1960 to 1965. An

estimated 1,800 tons of solid waste, including residential waste, construction debris, appliances,

scrap metal, scrap wood, and tree clippings were disposed at the site. The Public Works Department

collected solid waste twice a week using a dump truck, and deposited the solid waste at Site 3. The

solid waste was dumped directly onto the ground and left as mounds. Trenching and daily cover

were not employed as part of the disposal operations. No hazardous wastes were reported to have

been disposed at Site 3. Site 3 has remained inactive. The Navy has not removed any wastes from

Site 3. CERCLA investigation has determined that no action is necessary at this site.


According to the IAS, Site 4 was used as the Base's landfill from 1965 through possibly 1970. Prior

to its first use for solid waste disposal, the area may have been an orchard (based on 1950 and 1962

aerial photography from USEPA). Site 4 is named the Pistol Range Disposal Area because of its

proximity to the Base's pistol range.

While used as a disposal area, approximately 1,800 tons of waste including residential waste,

construction debris, appliances, scrap metal, and waste oil were reportedly disposed. According to

the IAS report, no hazardous wastes were reported to have been disposed at Site 4. No wastes were

removed from this site. CERCLA investigation has determined that no action is necessary at this

site.


According to the IAS, this site was reportedly used as a disposal site for mainly inert materials from

1980 through. 1983. Materials disposed of at the site consisted of leaves and brush, cuttings, empty

drums, tires, wood and pallets, demolition debris, automobiles, mattresses, appliances, office

furniture, and other similar materials. During the time period this site was used for disposal, the

majority of solid waste was taken off Base for disposal by a contractor. Items disposed of at the site

were those items the contractor would not dispose of, primarily because of their size and weight.

In 1982, the Environmental Engineering Survey conducted by the Navy recommended that these

materials be removed in order to "eliminate a point of habitation for insects, rodents, and other

animals, some of which could be disease vectors." This would also eliminate the need to apply for

a landfill operation permit.

Cleanup of the site was conducted by the Navy's Transportation Division as an "in-house" operation.

Approximately 360 tons of large metal pieces and equipment, abandoned vehicles, appliances, and

general Base scrap and trash were removed. In addition, 30 to 40 unsuspected 55-gallon drums of

unknown material and two to three transformers were removed. The drums and transformers were

disposed of by Base personnel. Soil was removed to 16 feet below-grade, acceptable materials

buried, and clean soil replaced to the surrounding land grade. The materials removed were placed

in a nearby municipal landfill. Because Site 5 has been cleaned up, it does not pose a threat to

4

human health or the environment. Therefore, since this site had been previously remediated prior

to listing of NSGA Sabana Seca on the NPL, USEPA's July 19, 1994 letter to the Navy determined

that no further investigation of Site 5 will be required.


According to the IAS, 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 equipment 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 Base'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, seven, PRAMITOL,

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 Base'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. The site was enclosed in a chain-

link fence to limit public access. The fence gate was kept locked at all times. Warning signs were

posted in English and Spanish. This area along Stone Road is patrolled regularly by military police.

CERCLA investigation has resulted in a protective asphalt cap that has been constructed on this site

as documented in a ROD dated, September 20, 1996 and construction completed in April 1997.


Leachate from the nearby municipal landfill has been observed entering this wet marshy area, which

has been designated as Site 7. The municipal landfill, which is located directly adjacent to the Base

property, has been in operation since the early 1970s. The Navy excessed this land to the Puerto

Rico Land Authority in 1963. The municipal landfill covers approximately 69 acres and has

received the following types of wastes: pharmaceutical, residential, and industrial wastes; old cars;

tires; and appliances. NSGA Sabana Seca has used the municipal landfill for the disposal of wastes

since approximately 1972.

The municipal landfill is situated in an area of karst topography known as the "haystack" hills.

Surface runoff ftom this area enters the Base. The presence of wastes on top of the karst topography

of the municipal landfill creates the potential for contaminant migration via the groundwater.

Groundwater from the municipal landfill discharges to the,swampy areas of the Base. Because of

the possibility of groundwater contamination from leachate migrating onto NSGA Sabana Seca

property, the municipal landfill poses a potential threat to human health and the environment.

The Navy has entered into an agreement with the Municipality of Toa Baja, municipal landfill

operators and Puerto Rico Environmental Quality Board (PREQB) to mitigate further impact to

NSGA Sabana Seca from the municipal landfill and will continue to monitor at Site 7 any

contaminant migration from the municipal landfill.

The terms of this agreement are the following: The Municipality of Toa Baja will develop a

mechanism to control the leachate migrating onto NSGA Sabana Seca property. In addition, Toa

Baja will develop with NSGA Sabana Seca concurrence mechanisms to prevent the erosion at the

NSGA Sabana Seca's security road in the corner, where the storm water/leachate runoff from the

Bayomon/Toa Baja Landfill's access road discharges onto NSGA Sabana Seca's property. Toa

Baja, as owner of the Bayamon/Toa Baja Landfill, will be responsible for funding and implementing

the agreed upon action.

The term of this agreement is from December 4, 1996 and will extend through post-closure

activities. PREQB will be expected to monitor contamination migration during this time.

2.2 Previous Investigations/Enforcement Activities

2.2.1 Previous Investigations

2.2.1.1 Initial Assessment Study

In 1984, an IAS was conducted for the Base. The purp9se 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 conducted on-site inspections and personnel interviews.

The IAS stated that, since no known hazardous waste were reportedly disposed at Site 1 or 3, these

sites did not pose a threat to human health or the environment. Therefore, Sites 1 and 3 were not

recommended for further investigation at the time of the IAS.

2.2.1.2 Initial Site Inspection

Because of the limited IAS information, the USEPA, the Navy, and the PREQB determined

additional studies were needed at Sites 1 and 3. In December 1991, Baker conducted site inspection

(SI) field activities. Three groundwater monitoring wells were installed at each site. Groundwater

and soil samples were collected and analyzed during two subsequent rounds of sampling (April 1993

and July 1993) at both sites. Nine surface soil samples were collected at Site 1 and analyzed for

Target Compound List (TCL) organics and Target Analyte List (TAL) inorganics.

2.2.1.3 Expanded Site Inspection

An expanded site inspection (ESI) was performed for Sites 1 and 3 to confirm background

conditions for surface soil and groundwater. The purpose of the ESI was to assess whether

unacceptable risks to human health from soil and groundwater (calculated from data collected in the

initial SI) were due to actual site conditions that existed from former site operations, or if the

constituents detected in the soil and groundwater were present in background and, therefore,

unrelated to the site.

As part of the ESI, an additional background monitoring well was installed. Two rounds of

groundwater samples and 20 background surface soil samples were collected. The groundwater

samples were collected using low-flow purging techniques to reduce turbidity. These background

concentrations were compared to the site specific analytical results to identify chemicals of concern

to use in a quantitative risk assessment.

2.2.2 Enforcement Activities

2.2.2.1 National Priorities Listing

NSGA Sabana Seca was proposed for inclusion on the National Priorities List, on June 24, 1988 and

was included on October 4, 1989. The concern about the pesticides at Site 6 was the primary reason

NSGA Sabana Seca was proposed for the NPL.

2.2.2.2 Federal Facilities Agreement

On March 19, 1992, the Navy, USEPA, and the PREQB entered into a Federal Facilities Agreement

(FFA) for NSGA Sabana Seca. The primary purpose of the FFA was to ensure that environmental

impacts associated with past and present activities at the Base were thoroughly investigated aqd

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. This agreement established roles and responsibilities and improved communication

between the Navy, USEPA, and PREQB. It provided for the expeditious completion of all remedial

actions necessary to protect the public health, welfare, and the environment consistent with

CERCLA/Superfund Amendment and Reauthorization Act (SARA) and the NCP. Under the FFA,

SIs were performed for Sites 1 and 3.

2.3 Site Inspections/Remedial Investigation/Leachate Diversion-Feasibility Study

All sampling and analysis, at all the sites at NSGA Sabana Seca were done in accordance with a

workplan prepared by the Navy and approved by USEPA and PREQB, and in accordance with the

USEPA Region II's CERCLA Quality Assurance Manual.

8

2.3.1 Site Inspections - Sites 2 and 4 - (01T-1)

Between 1985 and 1994, the 5 acre Pistol Range Disposal Area and the less than 2 acre Bunker 607

Disposal Area were sampled five times. The Navy performed a SI between 1991 and 1994. No

contaminants were detected in the groundwater, surface water, soil or sediments above Federal

Action levels. The final SI report summarized all site analysis results.

On December 2, 1996, the Navy released the final SI reports. The reports provided an in-depth

summary and discussion of site sampling activities and the risk assessment. The reports also

concluded that since there was no unacceptable risk to human health or the environment from the

contamination of soil, sediment, surface water, or groundwater at either site, no action was

necessary.

2.3.2 Remedial Investigation - Site 6 - (OU-2)

Between 1986 and 1993, the less than 1 acre site of the Former Pest Control Shop and adjacent areas

were sampled six times. The Navy performed a remedial investigation (RI) between October 1991

and October 1993. Chromium was detected only once in the groundwater above the Federal

Maximum Contaminant Level (MCL) at 119 micrograms per liter (fig/L). No pesticides were

detected in the groundwater and surface water and those pesticides detected in the soil and sediment

were below Federal action levels.

Since there are no applicable or relevant and appropriate requirements (ARARs) established for the

cleanup of soil, chemical-specific To Be Considered (TBC) criteria were evaluated, instead. A

chemical-specific TBC of 500 micrograms per kilogram (µg/kg) 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. The final RI/Feasibility Study(FS)

report summarized all site analysis results.

On May 2, 1996, the Navy released the final RI/FS report. The report provided an in-depth

summary and discussion of site sampling activities, a human health and ecological risk assessment,

and an analysis of remedial alternatives. The report also concluded that since there was no

unacceptable risk to human health or the environment from the pesticide contamination of soil that

has occurred at Site 6, no action was necessary. Nevertheless, the site is adjacent to a

playground/picnic area and the enlisted housing area. Therefore, as a reassurance to the public, the

Navy conservatively evaluated remedial alternatives that could limit the public's exposure to the

minimal contamination that may remain in the soil at Site 6. The RI/FS report provided a detailed

analysis of capping; excavation, removal and off-site incineration; and no action remedial

alternatives.

2.3.3 Leachate Diversion-Feasibility Study - Site 7

Though the waste stream did not originate from Navy property, the Navy conducted a Leachate

Diversion/Feasibility Study to try to address the problem. The FS provided eight alternatives for

an interim treatment of the leachate entering Navy property. The alternatives evaluated were

considered impractical, including leachate collection, because of the location of NSGA Sabana Seca

in a rainforest, with the exception of an engineered wetlands, which would use phytoremediation

technologies. A treatability study of the engineered wetland technology was conducted as a result

of the FS. The study consisted of constructing a small scale wetland to evaluate the

implementability and effectiveness of this technology. Due to unforeseen changes in landfill

operations and the hydrology upgradient of the Base, and susceptibility of the engineered wetland

technology to drought conditions, the study was canceled. The final FS report summarized all site

analysis results.

On December 20, 1996, the Navy released the final FS report. The report provided an in-depth

summary and discussion of the eight alternatives, all of which were determined to be impractical as

the report has also determined that the leachate flowing onto Navy property at Site 7, a collection

area for leachate from an off-Base source, is from the Bayamon Municipal Landfill, the operation

of which could not be controlled by the Navy. Therefore, on February 27, 1997, the USEPA notified

the Navy that no action was necessary and that a ROD would also not be required at Site 7. The

Navy has entered into a Partnering Agreement with the landfill owners and operators, and PREQB

to further address landfill leachate at Site 7.

10

2.4 ROD Findings

2.4.1 Sites 2 and 4 - (OU-1)

The Navy has prepared a No Action ROD for Sites 2 and 4 due to current site conditions,

environmental analyses and risk assessments. Though Sites 2 and 4 were formerly used as disposal

areas, no evidence exists to suggest that the soil, groundwater, surface water or sediment at either

site poses a risk to human health or the environment Based on cleanup objectives at other Federal,

State and Commonwealth hazardous waste sites, this alternative will be protective of human health

and the environment.

2.4.2 Site 6 - (0U-2)

On September 20, 1996, the Regional Administrator approved a ROD, which selected an asphalt

cap over the areas where pesticides were previously detected in the surface soils above TBC criteria.

The fence that is currently around portions of Site 6 will be removed. The area will be cleared and

grubbed. An eight inch subbase layer of gravel will be placed in the area to be capped. A four inch

layer of asphalt will be placed over the gravel subbase 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.

The cap will also eliminate the potential for any contact, human or environmental, with any

remaining minimal pesticide-contaminated soils. Based on cleanup objectives at other Federal, State

and Commonwealth hazardous waste sites, as well as recommendations from the U.S. Centers for

Disease Control, this alternative will be protective of human health and the environment.

2.5 Remedial Design/Remedial Action - Site 6 - (OU-2)

2.5.1 Design Activities

On February 14, 1996, the Navy submitted the draft Remedial Design (RD). The RD was finalized

on May 2, 1996 and approved by the Navy on July 15, 1996. The Navy has paid all of the remedial

action costs and will assume responsibility for all of the operation and maintenance (O&M)

requirements, as required by CERCLA. The Navy awarded the contract to OHM Remediation

Services Corporation. The draft Remedial Action Workplan dated July 15, 1996, was received by

11

USEPA on October 30, 1996, and approved by USEPA on December 19, 1996. The Remedial

Action Workplan was finalized by the Navy on January 14, 1997.

2.5.2 Remedial Construction Activities

The construction project consisted of three primary tasks; site preparation, backfill and compaction

of subbase, and asphalt application.

On January 14, 1997, the Navy held a pre-construction meeting at the Base. The,remedial action

field activities also commenced that day with clearing and grubbing. Preparation of Site 6 included

extensive clearing and grubbing activities, the removal of small trees and dense underbrush within

the fence, removal of crushed empty drums which formerly held drill soil cuttings, and the removal

of three large trees which were located slightly beyond the fenced perimeter but within the proposed

cap area. The e cleared vegetation, including the felled trees outside of the fenced area, were

transported to the Base compost. Drums, which held soil cuttings from previous site inspections,

were emptied on site and the contents placed beneath the final cap. Clearing and grubbing of Site 6

was completed on February 5, 1997.

Backfill and compaction activities, which began on February 7, 1997 and ended on March 14, 1997,

were delayed due to heavy precipitation. Because of muddy conditions, saturated soil was excavated

and replaced with crushed stone backfill, which facilitated the backfill completion while reducing

the need for additional, more costly, select soil backfill.

Asphalt and site restoration occurred from April 3 to 11, 1997. A four inch layer of asphalt was

applied over approximately 1,900 square yards, on top of the properly compacted subbase (>95%

compaction). A total of 180 cubic meters of topsoil was spread around the perimeter of the asphalt

cap, seeded and mulched.

On May 27, 1997, the Navy submitted a Remedial Action report to USEPA and PREQB signifying

successful completion of construction activities. Due to the contract modifications and weather

delays, the total remediation action contract cost ($261,000) exceeded the original $198,000

contract, by $63,000.

12

A final construction inspection was performed on April 7, 1997, during which the asphalt cap was

approved and accepted. The remaining punch list items, consisting of final top soil application,

seeding, and mulching, was finalized and approved and accepted by the on-site representative for

the Navy on April 14, 1997. The PREQB conducted an inspection on May 9, 1997; and USEPA

conducted an inspection on July 17, 1997, and both agencies concur that all remedial action had been

successfully executed by the Navy.

2.5.3 Summary of Operations and Maintenance

Site 6 O&M activities to be performed include routine inspections of the asphalt cap, mowing, and

maintenance of the perimeter fence. The Navy has assumed all responsibility for O&M. The asphalt

cap will require minimal maintenance by the Navy. The life expectancy of an asphalt cap is

approximately 20 to 25 years with routine maintenance. A top sealant will be applied periodically

to the asphalt surface to prevent deterioration.


The Navy's community relations staff conducted an active campaign to ensure that the residents

were well-informed about the activities at the Base. Community relations activities included: Site

Information/Photograph Albums; Site Brochures/Fact Sheets; a Community Relations Plan;

Technical Review Committee/Restoration Advisory Board meetings; and Public Awareness

Sessions.

2.7 Site Close Out

This No Action ROD, in lieu of a Final Close Out Report, documents that the Navy has completed

all construction activities for the NSGA Sabana Seca site in accordance with Close Out Procedures

for National Priorities List Sites (OSWER Directive 9320.2-09). No action has been determined to

be necessary for Sites 1, 2, 3, and 4; the Navy has cleaned up Sites 54nd 6; and Site 7 will be

addressed by the Municipality of Toa Baja, the party responsible for Site 7 contamination. This

decision documents that the Navy, USEPA and PREQB have determined that remedial actions for

this NSGA Sabana Seca site have been successfully implemented and no further response actions

are necessary. Therefore, the NSGA Sabana Seca site now qualifies for inclusion on the

13

Construction Completion List. The PREQB conducted an inspection on May 9, 1997; and, the

USEPA conducted an inspection on July 17, 1997, and both agencies concur that all remedial action

has been successfully executed by the Navy.

All cleanup actions specified in the ROD for Site 6 have been implemented. The asphalt cap

provides further assurance that Site 6 poses no threats to human health or the environment. The only

remaining activity to be performed is O&M that the Navy has guaranteed.

•USEPA will issue a Notice of Intent to Delete NSGA Sabana Seca site from the NPL.

A bibliography of all reports relevant to the completion of this NSGA Sabana Seca site under the

Superfund program is attached. These documents are available by calling the NSGA Sabana Seca

Public Affairs Officer at (787) 261-8307.


Because no hazardous substances remain at the site above health-based levels, a five-year review

does not apply to the NSGA Sabana Seca site.

3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION

The public participation requirements of CERCLAJSARA and the NCP have been met by the

following activities.

Restoration Advisory Board (RAB) members, which include representatives from regulatory

agencies, the Navy and the local community, have participated in the review of draft documents and

have worked together to finalize these documents.

A Community Relations Plan (CRP) for all sites at the Base was prepared in 1991 and is available

in English and Spanish. The CRP is part of the community right-to-know process. The primary

purpose of the CRP is to provide information and to promote constructive, effective communication

between the Base and the surrounding communities.

14

Although Puerto Rico is a Commonwealth of the United States, a large percentage of the population

is not fluent in English; Spanish is the main language of Puerto Rico. Therefore, the Navy had

pertinent summary documents translated into Spanish.

The Administrative Record, which contains all documents that form the basis for the selection of

a response action, is maintained at the Base library and at the Jaime Fonadella Garriga Public

Library in Toa Baja, Puerto Rico. The notice of availability for the Administrative Record for this

federal facility was first published on May 12, 1996 and May 13, 1996 in local newspapers. The

English version of the public notice was published in the San Juan Star; the Spanish version was

published in the Nuevo Dia.

The ESI Report and the Proposed Plan for these two sites were released to the public (i.e., were

placed in the Administrative Record) on June 17, 1997. The public notice indicating once again the

availability of the Administrative Record for the facility and specifically indicating the availability

of the ESI Report and the Proposed Plan for review was published on June 15, 1997 and June 16,

1997 in local newspapers. The English version of the notice was published in the San Juan Star, the

Spanish version was published in the Nuevo Dia. The Proposed Plan, ROD, the Site

Information/Photograph Album, fact sheets and the Administrative Record's introduction are

available in English and Spanish.

As indicated in the public notice, a public comment period was held from June 17, 1997 to July 17,

1997. The public comment period provided the public the opportunity to review the Administrative

Record and comment on the Proposed Plan. The public notice also requested public attendance to

the public awareness session which would be held on July 17, 1997. There was little public interest

in the Proposed Plan. The Navy received no requests for a time extension to the public comment

period.

On July 17, 1997, the Navy held the public awareness session in lieu of a public meeting even

though there had been no public request for a meeting. The public awareness session was held to

respond to public questions, if any, and to accept oral or written public comments on the Proposed

Plan. Had there been public comments received, a response to these comments would have been

included in the Responsiveness Summary section within this ROD. Fact sheets and a Site

Information/Photograph Album, both in English and Spanish, were provided during the public

15

awareness session to help the public understand the sites better. Navy representatives fluent in

English and Spanish and knowledgeable on this project were present at the public awareness session

to answer questions.

4.0 SCOPE AND ROLE OF THE RESPONSE ACTION

The "No Action" alternative has been selected for Sites 1 and 3. Current site conditions,

environmental analyses, and risk assessments indicate that no action is warranted at Site 1 or Site 3.

Though Sites 1 and 3 were formerly used as landfills, the risk to human health and the environment

is low. No evidence exists to suggest that the soil or groundwater at either site poses a risk to human

health or the environment. No further studies will be conducted at these sites. No previous removal

or interim remedial actions have been conducted at Sites 1 and 3, and no future remedial actions are

proposed at these sites.

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 at

Sites 1 and 3. Based upon the initial SI, the ESI, and the site history, the source of contamination

involves the former use of Sites 1 and 3 as Base landfills. No additional sources of contamination

were identified.

5.1 Initial SI Data Results

The analytical results of the initial SI are discussed in the following paragraphs.

5.1.1 Soil Contamination - Site 1

Nine surface soil samples were collected at Site 1 and analyzed for TCL organics and TAL

inorganics during two rounds of sampling. Organic compounds were detected in both rounds of

sampling. The organic compounds detected in the first round included acetone (0.023J milligrams

per kilogram [mg/kg]), methylene chloride (0.004J mg/kg), (the "J" denotes an estimated

concentration), di-n-butylphthalate (0.067J mg/kg), and bis(2-ethylhexyl) phthalate (0.110J mg/kg).

16

Only bis(2-ethylhexyl)phthalate (0.069J mg/kg) was detected in the second round. The organic

compounds were also detected in field, equipment rinsate, or laboratory blanks, and therefore were

determined to be laboratory or field induced contaminants. Low levels of inorganics were detected

above background levels. Some of the inorganics-detected included aluminum (2,990 to

21,300 mg/kg), arsenic (2.5 to 14.7 mg/kg), copper (4.9 to 39.6 mg/kg), and mercury (0.12 to

0.45 mg/kg).


Seven surface soil samples were collected at Site 3 and analyzed for TCL organics and TAL

inorganics during two rounds of sampling. The organics chlorobenzene and toluene were detected

at maximum concentrations of 0.041J mg/kg and 0.034J mg/kg during Round 1, respectively. The

pesticide. 4,4'-DDT (0.036 mg/kg) was detected during Round 2. Low levels of inorganics were

detected above background levels. Some of the inorganics detected included arsenic (4.0 to

14.5 mg/kg), calcium (19 to 298,000 mg/kg), copper (6.6 to 41.1 mg/kg), nickel (6.2 to 24.8 mg/kg),

and vanadium (41.6 to 118 mg/kg).

5.1.3 Groundwater Contamination - Site 1

Groundwater samples were collected at Site 1 from three monitoring wells and were analyzed for

TCL organics and TAL inorganics during two rounds of sampling. Chloroform(16 gg/L and

10 gg/L) and carbon tetrachloride (10 gg/L) were the only organic compounds detected in the

sampled groundwater. These detected concentrations were compared to the MCLs. MCLs are

standards for public water supplies promulgated under the Safe Drinking Water Act. The MCLs for

chloroform and carbon tetrachloride are 100 gg/L and 5 gg/L, respectively. The chloroform

detected at Site 1 was below the MCL. The carbon tetrachloride detected exceeded the MCL in one

well. Inorganics (in the filtered samples) were not detected above MCLs.

5.1.4 Groundwater Contamination- Site 3

Groundwater samples were collected at Site 3 from three monitoring wells and were analyzed for

TCL organics and TAL inorganics during two rounds of sampling. Chloroform was the only organic

compound detected at concentrations of 4J gg/L to 8J gg/L. These detected concentrations are

17

below the MCL of 100 gg/L. Filtered samples of groundwater did not contain any inorganics above

MCLs.

5.2 ESI Data Results

The analytical results of the ESI are discussed in the following paragraphs.

5.2.1 Background Soil Contamination - Sites 1 and 3

The background surface soil samples contained inorganics and pesticides. The inorganics were

generally below the concentrations detected in the site-specific background soil samples from Sites 1

and 3. Aluminum, arsenic, chromium (as chromium VI), copper, thallium, and vanadium were

detected at levels above the range of background concentrations at Site 1 and Site 3. Mercury and

selenium were detected at levels above background concentrations at Site 1. Nickel was detected

at levels above background concentrations at Site 3. The pesticides aldrin, heptachlor epoxide,

4,4'-DDT, 4,4'-DDE, endrin, endrin aldehyde, endrin ketone, alpha-chlordane, and gamma-chlordane

were detected in the background surface soil samples. 4,4'-DDT was the only pesticide detected in

the site-specific samples (initial SI for Site 3).

5.2.2 Background Groundwater Contamination - Sites 1 and 3

Chloroform and carbon tetrachloride were the only organic compounds detected in the groundwater.

These compounds were detected at concentrations below their MCLs. Groundwater analyzed for

total inorganics contained aluminum, arsenic, barium, manganese, and mercury at low

concentrations. The dissolved inorganic analyses of groundwater showed the presence of aluminum,

barium, and manganese. The concentrations of dissolved and total inorganics were similar due to

the utilization of low flow purging techniques. The total and dissolved inorganics were below MCL

levels.

6.0 SUMMARY OF SITE RISKS

As part of the SI, a qualitative risk assessment (RA) was performed to determine the potential effects

on human health as a result of exposure to contaminants of potential concern (COPCs). As part of

18

the ESI, a quantitative RA was performed for each site. The following subsections briefly describe

the results of the RAs. The SI and the ESI reports contain more extensive information pertaining

to the RAs.

6.1 Initial SI Qualitative Risk Assessment

6.1.1 Qualitative RA - Site 1

The chloroform detected in the Site 1 groundwater during Rounds 1 and 2 did not exceed its MCL

value. Carbon tetrachloride was detected in one well during both rounds of sampling and did exceed

its MCL value. Given the sporadic occurrence of carbon tetrachloride (only detected in one well),

the potential for human health effects was determined to be negligible.

Volatile and semivolatile organic constituents were detected in Round 1 and Round 2 soil samples.

The phthalate esters di-n-butylphthalate, bis(2-ethylhexyl)phthalate and diethylphthalate were

detected in quality control samples, as were the volatile organics acetone and methylene chloride.

These chemicals are common laboratory contaminants (USEPA, 1989), therefore, Site 1 soils were

not considered further in the RA.

6.1.2 Qualitative RA - Site 3

Chloroform was detected in the groundwater from Site 3 during Rounds 1 and 2. The concentrations

detected were below the MCL. Therefore, the qualitative RA concluded that there was no threat to

human health or the environment due to chloroform.

Chlorobenzene, toluene, and 4,4'-DDT were detected at low levels in the soil at Site 3 during one

round of sampling. The presence of these chemicals was not confirmed by -the other round of

sampling. The levels detected were beldw the risk-based criteria (RBC) values. RBC values are

risk-based conservative benchmarks developed by USEPA Region III for comparing results of•

analytical data. Therefore, the RA concluded that there was no threat to human health or the

environment from these chemicals.

19

6.2 JESI Quantitative Risk Assessment

Because of additional questions on the results of the qualitative RA, a quantitatiVe RA was

conducted for Sites 1 and 3 to evaluate the potential human health risks associated with exposure

to surface soil and groundwater at Sites 1 and 3. The quantitative RA was conducted in accordance

with the Risk Assessment Guidance for Superfimd (RAGS), Part A, Human Health Evaluation

Manual (USEPA, 1989). The results of the quantitative RA for each site are discussed below.

The soil COPCs retained for evaluation in the RA included arsenic, beryllium, chromium,

manganese, and vanadium for the soil at Sites 1 and 3. COPCs retained for the Site 1 groundwater

included carbon tetrachloride, chloroform, and arsenic. The COPCs retained for the Site 3

groundwater included chloroform, heptachlor epoxide, and arsenic. Tables 1 and 2 contain a

summary of the COPCs for soil and groundwater, respectively.

The quantitative RA considered the most likely routes for potential exposure for both current and

future exposure scenarios. To calculate the risks, the incremental lifetime cancer risks (ILCRs) were

calculated for different scenarios (see Table 3). The ILCR is a number that represents the potential

cancer risk that is above the background cancer risk to unexposed individuals. Potential

carcinogenic risks were evaluated using the cancer slope factors (CSFs) developed by USEPA (see

Table 4) for the COPCs. CSFs have been developed for estimating excess lifetime cancer risks

associated with exposure to potentially carcinogenic chemicals. A CSF is multiplied by the

estimated chemical intake to generate an upper-bound estimate of the excess lifetime cancer risk

associated with exposure to the compound at that intake level. A number called the hazard quotient

(HQ) is used to determine the non-carcinogenic effects of chemical exposure. The hazard index (HI)

is obtained by adding the HQs for all chemicals, within a medium, that impact a particular receptor

population (see Table 5). The HI number is compared to unity (1.0).

The HI is a representation of the chronic daily intake divided by a safe or reference dose (RfD). RfD

(see Table 4) is an estimate of a daily exposure level for the human population, including sensitive

subpopulations, that is likely to be without an appreciable risk of adverse effects during a lifetime.

Ratios less than one indicate that non-carcinogenic health effects are unlikely. Ratios greater than

one indicate the potential for the occurrence of adverse non-carcinogenic health effects.

20

The human receptors in the vicinity of Sites 1 and 3 include both on-Base and off-Base personnel.

This includes resident adults, resident children, and on-site workers. The Base housing areas are

approximately 3,500 feet from Site 1 and 1,700 feet from. Site 3. The distance to the nearest

potable water well is approximately 2,500 feet from Site 3 at the Department of Health and Human

Services CPRC. The closest off-Base residence is in the village of Sabana Seca, approximately

1 mile to the northeast of both sites. The potential receptors evaluated in the quantitative RA

included on-site workers, present and future adult and child trespassers, on-site future adult and

younger child residents, and current on-site adult and younger child residents. See Table 6 for the

exposure pathways.

The quantitative RA presented the following conclusions with respect to carcinogenic and

non-carcinogenic risks.

Carcinogenic Risk

For both Site 1 and Site 3 soil, the ingestion ILCRs for the on-site worker, adult

trespasser, child trespasser, adult future on-site resident, and the child future on-site

resident fell within the USEPA's target risk range of 10 4 to 10' (see Table 3).

• For both Site 1 and Site 3 groundwater, the ILCRs for ingestion of organics and

filtered or unfiltered inorganics in groundwater for the residential adult, residential

child, and on-site worker fell within the USEPA's target risk range (see Table 3).

Non-carcinogenic Risk

• As shown on Table 5, for Site 1 and Site 3 soil, the HI values for incidental

ingestion by on-site workers, adult trespassers, older child trespassers, and future

on-site adult residents were less than one indicating no adverse health effects. The

total HI for the future on-site resident younger child slightly exceeded unity.

Arsenic was a major contributor to the total HI number. None of the individual

contaminants that contributed to the total HI are likely to cause adverse health

effects.

21

• For both Site 1 and Site 3 groundwater, none of the scenarios evaluated resulted in

HI values that exceeded one, indicating no adverse health effects (see Table 5).

In conclusion, no adverse health effects could be attributed to the contaminants detected in the soil

or groundwater at Site 1 or Site 3. One scenario, the future on-site resident younger child with

incidental exposure to surface soil, did generate a non-carcinogenic risk. A major contributor to this

risk is arsenic which is a naturally occurring element in soil and was detected in the background

samples. The individual risk due to arsenic did not exceed one, but when this risk was coupled with

the risks from the additional COPCs, the HE exceeded one. However, the COPCs are non-additive

since they do not affect similar target organs. Therefore, the RAs concluded that the analytes are

not likely to cause adverse health effects to human receptors.

6.3 Uncertainty Analysis

Biological and environmental systems are not directly comparable to associated scientific disciplines

such as chemistry and mathematics, due to the natural variability of living systems. A RA is based

upon a mixture of sciences with varying levels of certainty, and the final estimation of the RA is

only as certain as the least certain component in the estimate. The results of the RA are presented

in terms of the potential for adverse effects based upon a number of very conservative assumptions.

The tendency to be conservative is an effort to err on the side of the protection of health. The risks

are indicators of possible risk, not a true measurement of actual risk. The human health risk

evaluation is intended to contribute to the decision-making process and the management of NSGA

Sabana Seca by interpreting the significance of the observed contamination.

Uncertainties are encountered throughout the process of performing a RA. The exposure modeling

can produce divergent results unless standardized assumptions are used and the possible variation

in others are clearly understood. Similarly, toxicological assumptions, such as extrapolating from

chronic animal studies to human populations also introduce a great deal of uncertainty into the risk

assessment. This section discusses sources of uncertainty inherent in the following elements of the

baseline human health RA performed for Sites 1 and 3:

Hazard assessment and analytical data (environmental chemistry sampling and

analysis; misidentification or failure to be all-inclusive in chemical identification).

22

Exposure assessment (choice of models and input parameters and fate and transport

modeling).

• Toxicity assessment (choice of models or evaluation of toxicological data in dose-

response quantification).

• Risk characterization (assumptions concerning exposure scenarios and population

quantification).

The variation of any factor used in the calculation of the exposure concentration will have an impact

on the total carcinogenic and noncarcinogenic risk. Uncertainties associated with this RA are

presented in Table 7 and discussed in the following paragraphs.

6.3.1 Analytical Data and Selection of COPCs

The development of a RA depends on the reliability of uncertainties with the analytical data

available to the risk assessor. Analytical data are limited by the precision and accuracy of the

methods of analysis. Analytical data are not absolute numbers and variability in sample results is

inherent. The amount of variability in analytical results depends upon the sample media and the

presence of interfering compounds. In addition, the number of sampling points can also directly

affect the reliability of a risk evaluation. However, the potential effects on the overestimation or .

underestimation of risks is considered to be low.

The contaminant concentration in each medium to which a human receptor could potentially be

exposed was estimated by using the maximum detected concentration for each data set. This means

that, in general, an attempt was made to err on the side of health-protectiveness.

Analytical results for surface soil and groundwater samples obtained during the ESI were subjected

to an independent third party data validation. TCL organics and TAL inorganic data were qualified

"J" (estimated) for a number of quality control reasons, therefore, in some instances the maximum

concentrations used could be biased high. This was considered to be an acceptable bias, in this case,

since conservative risk scenarios were desired for evaluation.

23

t

Inorganics, were detected in groundwater samples collected from shallow monitoring wells at both

sites. A limited number of these analytes exceeded federal groundwater quality standards. The

distribution of detected inorganics in groundwater followed no discernible pattern that would

indicate a likely source. Additionally, inorganic levels in soil were not elevated to the point where

soil would be believed to be considered as the source of groundwater contamination. The

concentrations of detected inorganics is higher in the unfiltered (total) samples than in the filtered

(dissolved) samples. This indicates that the inorganics detected in groundwater samples at Sites 1

and 3 may be due predominantly to the presence of soil particles entrained in the groundwater

samples and may not be attributable to site operations. Arsenic was nonetheless retained as a

chemical of potential concern for both sites in the baseline risk assessment.

Similarly, the presence of chloroform may be from a source not associated with Sites 1 and 3,

because chloroform was also found in another monitoring well, upgradient from these sites.

6.3.2 Exposure Assessment

In performing exposure assessments, uncertainties arise from two main sources, estimating the

transport and fate of a compound in the environment including the estimate for release and transport

within a particular environmental medium, and, the estimation of chemical intakes resulting from

contact by a receptor with a particular medium. However, the use of the maximum detected soil

concentrations in estimating the chronic daily intake, reduces the potential for underestimating

exposure at these sites. To estimate an intake, certain assumptions must be made about exposure

events, exposure durations, and the corresponding assimilation of constituents by the receptor.

Exposure factors have been generated by the scientific community and have undergone review by

the USEPA. The USEPA has published an Exposure Factors Handbook which contains the best and

latest values. Regardless of the validity of these exposure factors, they have been derived from a

range of values generated by studies of limited numbers of individuals. In all instances values used

in this risk assessment, scientific judgements, and conservative assumptions agree with those of the

USEPA. Conservative assumptions, designed as not to underestimate daily intakes, were.employed

throughout this risk assessment and are adequately protective of human health.

24

6.3.3 Toxicity Assessment

In formulating quantitative estimates of the toxicity of varying dosage of a compound to human

receptors, uncertainties arise from two sources. First, data on human exposure and the subsequent

effects are usually insufficient, if they are available at all. Human exposure data usually lack

adequate concentration estimations and suffer from inherent temporal variability. Therefore, animal

studies are often used and new uncertainties arise from the process of extrapolating animal results

to humans. Second, to obtain observable effects with a manageable number of experimental

subjects, high doses of a compound are often used. In this situation, a high dose means that high

exposures are used in the experiment with respect to most environmental, exposures. Therefore,

when applying the results of the animal experiment to the human condition, the effects at the high

doses must be extrapolated to approximate effects at lower doses.

In extrap6lating effects from high doses in animals to low doses in people, scientific judgment and

conservative assumptions are employed. In selecting animal studies for use in dose-response

calculations, the following factors are considered:

• Studies are preferred where the animal closely mimics human pharmacokinetics.

Studies are preferred where dose intake most closely mimics the intake route and

duration for humans.

Studies are preferred which demonstrate the most sensitive response to the

compound in question.

Promulgated CSF values represent the 95th percent upper confidence limit (UCL) value derived

using the linear multistage statistical model so as to not underestimate carcinogenic potential.

The use of conservative assumptions in the use of maximum detected concentration results in

quantitative indices of toxicity that are not expected to underestimate potential toxic effects, but may

overestimate these effects by an order of magnitude or more. This conservatism could be further

compounded by the use of multiple data bases which contain toxicological indices no longer on line

in the Integrated Risk Information System.

25

For compounds believed to cause threshold effects (i.e. noncarcinogens) safety factors are employed

in the extrapolation of effects from animals to humans and from high doses to low doses.

The use of conservative assumptions results in quantitative indices of toxicity that are not expected

to underestimate potential toxic effects, but may overestimate these effects by an order of magnitude

or more.

6.3.4 Risk Characterization

Uncertainties associated with risk characterization include the assumption of chemical additivity and

the inability to predict synergistic or antagonistic interactions between COPCs. These uncertainties

are inherent in any inferential risk assessment. USEPA promulgated inputs to the quantitative risk

assessment and toxicological indices are calculated to be , protective of the human receptor and to err

conservatively, so as to not underestimate the potential human health risks.

The baseline human health RA has been conducted with the understanding that there are significant

limitations in the data. In particular, these limitations relate to the small sample data set available

for consideration.

6.4 Ecological Risk Assessment

The area around Sites 1 and 3 is heavily vegetated. Limestone hills, known as haystack hills, and

sinkholes are at least 2,500 feet southwest of Sites 1 and 3. The haystack hills are inhabited by the

Puerto Rican Boa, the White-crowned Pigeon, and various plant species that are listed as

endangered/threatened species. No ecological RA was conducted at either site because these types

of assessments are not included in Federal guidance for conducting SIs.

7.0 DESCRIPTION OF THE "NO ACTION" ALTERNATIVE

The selected remedial action for Sites 1 and 3 is "no action". No adverse health effects could be

attributed to the contaminants detected in the soil or groundwater at Site 1 or Site 3, therefore, no

further action is deemed appropriate. "No action" involves taking no further investigative or.

26

remedial actions at the sites and leaving them as they currently are. There are no costs associated

with the "no action" alternative.

8.0 RESPONSIVENESS SUMMARY

8.1 Overview

A public comment period was held from June 17, 1997 through July 17, 1997. A public awareness

session, in lieu of a public meeting, was held on July 17, 1997. No public comments were received.

8.2 Community Preferences

A record review of the NSGA Sabana Seca files indicates that the community involvement centers

mainly on social nature, including the community outreach programs and Base/community clubs.

Generally, there are two communities at Sabana Seca: the Base, English speaking community and

the surrounding Spanish speaking community. The Base has actively pursued participation from

both communities.

For all sites at the Base, community relations activities to date are summarized below:

Prepared a Community Relations Plan in English and Spanish.

• Prepared Site Information/Photograph Albums in English and Spanish during the

public awareness sessions.

• Prepared Fact Sheets in English and Spanish during the public awareness sessions.

Established the Administrative Record/information repository at two locations (one

location was on-Base and one location was off-Base).

• Held Technical Review Committee/Restoration Advisory Board meetings to review

the status of the remedial activities on the Base.

27

Released Proposed Plans in English and Spanish for. public review.

8.3 Summary of Comments Received During the Public Comment Period and Agency

Responses

No comments were received during the public comment period, and no comments were received

from those who attended the public awareness session. A representative from USEPA and PREQB

attended the public awareness session.

9.0 BIBLIOGRAPHY

This bibliography presents a listing of all of the documents that were prepared as part of the

Installation Restoration (IR) program at NSGA Sabana Seca. The documents are listed by site in

chronological order.

NSGA Sabana Seca - Basewide

Initial Assessment Study of Naval Security Group Activity, Sabana Seca and Naval

Communications Station. Puerto Rico. Greenleaf, Telesca/Ecology and

Environment. September 1984.

Remedial Investigation - Interim Report to Determine Dispersion and Migration of

Specific Chemicals, NSGA Sabana Seca. Puerto Rico. Draft. Hunter/ESE, Inc.

January 1989.

• Final Work Plan, Remedial Investigation/Feasibility Study for the Naval Security

Group Activity, Sabana Seca, Puerto Rico. Versar, Inc. August 1991.

• Site Information/Photograph Album, Naval Security Group Activity. Sabana Seca,

Puerto Rico. Draft. Baker Environmental, Inc. May 31, 1996.

Site Information/Photograph Album, Naval Security Group Activity. Sabana Seca,

Puerto Rico. Draft Final. Baker Environmental, Inc., July 15, 1997.

28

Sites 1 and 3

• Work Plan Addendum for Sites I and 3. Site Inspection. NSGA Sabana Seca.

Final. Baker Environmental, Inc. February 1993.

Site Inspection Report for Site 1 South Stone Road Disposal Area. Naval Security

Group a Seca, Puerto Rico. Draft. Final. Baker Environmental, Inc.,

October 1994.

Site Inspection Report for Site 3 North Stone Road Disposal Area, Naval Security

Group Activity. Sabana Seca, Puerto Rico. Draft Final. Baker Environmental, Inc.,

October 1994.

• Work Plan Addendum for Sites I and 3 Expanded Site Inspection, NSGA Sabana

Seca. Final. Baker Environmental, Inc., March 1996.

Expanded Site Inspection for Sites I and 3. Naval Security Group Activity Sabana

Seca, Puerto Rico. Final. Baker Environmental, Inc., March 1997.

• Superfund Proposed Plan, Site 1 - South Stone Disposal Area. Site 3 - North Stone

Road Disposal Area. U.S. Naval Security Group Activity. Sabana Seca, Puerto

Rico. Final. Baker Environmental, Inc., June 1997.

Record of Decision, Site 1 - South Stone Disposal Area, Site 3 - North Stone Road

Disposal Area, U.S. Naval Security Group Activity, Sabana Seca. Puerto Rico.

Final. Baker Envfronmental, Inc.

Sites 2 and 4

• Site Investigation/Risk Assessment Report. Bunker 607 Area (Site 2), Naval

Security Group Activity, Sabana Seca, Puerto Rico. Final. Versar, Inc.

December 1996.

29

Site Investigation/Risk

Ponding Area. Site 4/7. Naval Security Group Activity, Sabana Seca, Puerto Rico.

Final. Versar, Inc. December 1996.

Superfund Proposed Plan, Site 2 - Bunker 607 Disposal Area, Site 4 - Pistol Range

Disposal Area. U.S. Naval Security Group Activity. Sabana Seca. Puerto Rico.

Final. Baker Environmental, Inc. June 1997.

Record of Decision, Site 2 - Bunker 607 Disposal Area. Site 4 - Pistol Range


Final. Baker Environmental, Inc.

Site 5

USEPA issued No Further Response Action Planned concurrence letter. July 1994.

Site 6

• Superfund Proposed Plan. Site 6 - Former Pest Control Shop U.S. Naval Security

Group Activity. Sabana Seca, Puerto Rico. Baker Environmental, Inc.,

March 1996.

Remedial Investigation/Feasibility Study, Pest Control Shop. Site 6, Naval Security

Group Activity, Sabana Seca. Puerto Rico. Versar, Inc., May 1996.

• Final Design, Installation of Asphalt Cap. Site 6, Former Pest Control Shop. U.S.

Naval Security Group Activity. Sabana Seca. Puerto Rico. Baker Environmental,

Inc., May 1996 (signed July 1996).

• Record of Decision. Site 6, Former Pest Control Shop, Naval Security Group

Activity. Sabana Seca, Puerto Rico. Final. Baker Environmental, Inc.,

September 1996.

3G

• Work Plan for Installation of Asphalt Cap. Site 6, Former Pest Control Shop, NSGA

Sabana Seca. Final. OHM, Incorporated. January 1997.

Remedial Action Report for Asphalt Cap at Site 6. Former Pest Control Shop,

NSGA Sabana Seca. Final. OHM, Inc. August 1997.

Site 7

Leachate Diversion/Feasibility Study. Naval Security Group Activity, Sabana Seca.,

Puerto Rico. Final. Baker Environmental, Inc. December 1996.

• USEPA issued No Further Response Action Planned concurrence letter,

February 1997.

31

Thallium 0.480.1-0.31 0.47

Vanadium 10.5-60.4 23.8-139 41.6-118

Site 1Range of Positive

Detections(mg/kg)

2,990-21,300

2.5-14.7

349-3,480

7.9-83.1

4.9-39.6

0.12-0.45

5.2-11

74.5-211

0.47-1.6

Site 3Range of Positive

Detections(mg/kg)

6,410-14,300

4.0-14,5

019-298,000

12.7-43

6.6-41.1

6,330-26,500

ND

6.2-24.8

117-362

0.59-1.2

Inorganic Analytes

Range of BackgroundConcentrations

(mg/kg)

Aluminum 876-8,290

zn 1 -

Arsenic 1.0-7.8

...

Calcium+ 422-243,000

Chromium (as Chromium VI) 2.8-35.6

Copper 5.2-32.9

Iron+ 1,910-20,000

LMStli

Mercury 0.11-0.31

Nickel 1.6-15.7

Potassium+ 45.8-1.27

Selenium 0.24-1.2

....::.,

TABLE 1

CONTAMINANTS OF POTENTIAL CONCERN FOR THE HUMAN HEALTH RISK ASSESSMENTSURFACE SOIL DATA SUMMARY

RANGE OF INORGANIC POSITIVE DETECTIONSFOR BACKGROUND, SITES 1 AND 3


Note: Shading indicates occurrences of background exceeding corresponding sample concentrationsmeasured at both sites.

Mg/kg = milligrams per kilogramND

= not detected

TABLE 2

CONTAMINANTS OF POTENTIAL CONCERNFOR THE HUMAN HEALTH RISK ASSESSMENT

GROUNDWATER DATA SUMMARYESI, ROUND 4(' )SITES 1 AND 3


Constituent(Z)

Range ofBackground

Concentrations(3)(MA-)

Range of Positive Detections(Low-flow purge sampling method)

Site 1 , Site 3

Total( lga)

Dissolved(AWL)

Total( lga)

Dissolved(llga)

Volatiles:Carbon tetrachloride (5) ND 4J NA ND NA

Chloroform (100) , ND 9J - 10 NA 3J - 7J NA

Toluene (1,000) 4J ND NA ND NA

Pesticides:Heptachlor epoxide(0.2) 0.06NJ ND NA 0.06NJ NA

Inorganics:Aluminum (--) 141 - 376 117 - 637 98.9 - 131 107 - 141 102 - 141

Arsenic (50) 2 1.2 1.7 1.1 - 1.9 ND

Barium (2,000) 25.2 - 42.6 16.2 - 19.9 15.2 - 18.1 16.2 - 23.7 13.9 - 21.7

Calcium+ (--) 101,000 - 115,000 83,800 - 106,000 81,700 - 103,000 78,800 - 105,000 77,600 - 103,000

Iron+ (--) 1,490 1,460 ND ND ND

Magnesium+ (--) 5,160 - 5,200 3,760 - 6,450 3,730 - 6,320 3,690 - 5,300 ' 3,820 - 5,190

Manganese (--) 55.2 - 292 10.9B - 50.4 11.4 - 27.5 55.5 63.4

Mercury (2 ,,. :: 0.21 ND ND ND

Potassium+ (--) 2,040 - 1,560 1,410 - 1,790 1,310 - 1,890 ND 926 - 1,510

Selenium (50) ND ND 2.3J ND 1.1J

Sodium+ (--) 15,500 - 37,200 16,300 - 33,000 16,600 - 32,100 13,000 - 30,400 13,400 - 30,500

Notes:

Rounds 3 and 4 data similar; Round 4 presented since it is the most recent data.Values in parentheses represent Federal MCLs (pg/L). Exceedences of MCL are shaded. (--) indicates no MCLs are available.Dissolved concentrations not presented, but are similar to totals due to low flow techniques.Location S3BW01(Bataan Rd.); detected also during round 3 at 6.5 ng/L.

NA - Not applicable- Not detected

+ - Essential nutrientJ - Estimated valueN - Tentative identification; consider present.B - Reported value is less than the Contract Required Detection Limit (CRDL) but greater than or equal to the Instrument Detection Limit.p.g/L - micrograms per liter

(I)(2)

(3)(4)

TABLE 3

SUMMARY OF INCREMENTAL LIFETIME CANCER RISKSINGESTION EXPOSURES TO SURFACE SOIL COPCs

TRESPASSERS, ON-SITE WORKERS, AND FUTURE ON-SITE RESIDENTSSITE 1 AND 3


On-siteWorkers

Local ResidentTrespassers

FutureOn-site Residents

AdultOlderChild Adult

YoungChild

Site 1 4.1E-06 4.7E-07 2.7E-07 1.4E-05 2.5E-05

Site 3 , 4.1E-06 4.8E-07 2.7E-07 1.4E-05 2.6E-05

SUMMARY OF INCREMENTAL LIFETIME CANCER RISKSINGESTION EXPOSURE TO ORGANIC AND UNFILTERED AND

FILTERED INORGANIC GROUNDWATER COPCsFUTURE ADULT AND YOUNG CHILD RESIDENTS

SITE 1 AND 3NAVAL SECURITY GROUP ACTIVITY

SABANA SECA, PUERTO RICO

Site

Residential Adult Residential Young Child

UnfilteredGroundwater

FilteredGroundwater


FilteredGroundwater

Site 1 2.8E-05 3.7E-05 1.3E-05 1.7E-05

Site 3 4.0E-05 6.9E-06 1.9E-05 3.2E-06

SUMMARY OF INCREMENTAL LIFETIME CANCER RISKSINGESTION EXPOSURES TO ORGANIC AND UNFILTERED AND

FILTERED INORGANIC GROUNDWATER COPCsCURRENT ADULT AND YOUNG CHILD RESIDENTS, ON-SITE WORKERS



Site

Residential Adult Residential Young Child On-site Workers


FilteredGroundwater


FilteredGroundwater


FilteredGroundwater

Site 1 3.7E-06 4.9E-06 8.7E-06 1.1E-05 8.3E-06 1.1E-05

Site 3 5.4E-06 9.2E-07 1.3E-05 2.2E-06 1.2E-05 2.1E-06

TABLE 4

TOXICITY VALUES - RID AND SLOPE FACTORSSITES 1 AND 3

TOXICITY FACTORS FOR CHEMICALS OF POTENTIAL CONCERNNAVAL SECURITY GROUP ACTIVITY


ChemicalOral CSF

(mg/kg/day)- 1Tumor Types(carcinogens)

Oral RfD(mg/kg/day)

Critical Effects(Systemic Toxicants)

USEPAWeight-of-Evidence

Carbon Tetrachloride 1.3 x 10-' (I) Liver tumors 7.0 x 10 (0 Central nervous system(CNS), kidney and livereffects

B2

Chloroform 6.1 x 10' 0) Renal tumors 1.0 x 10' 0) CNS, liver, kidney andcardiovascular effects

B2

Heptachlor Epoxide 9.1 0) Liver tumors 1.3 x 10-5 (0 Increased liver weight B2Arsenic 1.5 (2) Liver, kidney,

lung, bladderand skintumors

0.0003 (2) Liver, cardiovascular, CNS,and tissue respirationeffects. Also, keratosis andhyperpigmentation.

A

Beryllium 4.3 (2) Lung tumors 0.005(2) Respiratory effects andberylliosis.

B2

Chromium NA NA 5.0 x 10' 0) Renal tubular necrosis andhepatic effects.

Manganese NA NA 0.023 (2) CNS effects. DVanadium NA NA 7.0 x 10' (0 Gastrointestinal

disturbances anddiscoloration of the mouthand tongue.

D

Notes:

0) USEPA, 1996a. USEPA Region III Risk-Based Concentration Table, January - June 1996.(2) USEPA, 1996b. Integrated Risk Information System (IRIS).

NA = Not Availablemg/kg/day = milligrams per kilogram per dayCSF = cancer slope factorRfD = reference dose

TABLE 5

SUMMARY OF HAZARD INDICESINGESTION EXPOSURE TO SURFACE SOIL COPCs

TRESPASSERS, ON-SITE WORKERS AND FUTURE ON-SITE RESIDENTSSITE 1 AND 3


SiteOn-site

Workers

Local ResidentTrespassers

FutureOn-site Residents

'Adult

OlderChild Adult

YoungChild

Site 1 0.05 <0.01 0.01 0.13 1.2

Site 3 0.04 <0.01 0.01 0.12 1.1

SUMMARY OF HAZARD INDICESINGESTION EXPOSURE TO ORGANIC AND UNFILTERED AND

FILTERED INORGANIC GROUNDWATER COPCsFUTURE ADULT AND YOUNG CHILD RESIDENTS



Site

ResidentialAdult

ResidentialYoung Child


FilteredGroundwater


FilteredGroundwater

Site 1 0.29 0.34 0.68 0.79

Site 3 0.32 0.15 0.74 0.34

SUMMARY OF HAZARD INDICESINGESTION EXPOSURES TO ORGANIC AND UNFILTERED AND

FILTERED INORGANIC GROUNDWATER COPCsCURRENT ADULT AND YOUNG CHILD RESIDENTS, ON-SITE WORKERS



Site

ResidentialAdult

ResidentialYoung Child

On-site Workers


FilteredGroundwater .


FilteredGroundwater


FilteredGroundwater

Site 1 0.29 0.34 0.68 0.79 0.1 0.12

Site 3 0.32 0.15 0.74 0.34 0.11 0.05

A

(,) ts4E-K 004'

1:4

E-4

zC/1

° ;g t•—(o•—n

,̀t 0.ct Z 0.4

re)

1,:i at OWE-(A0Z g a-<Z(/)'‹OaP-n d

1-" Uci) E*UZ •••

0,4 (,)0 :p4 UO.k

X u O cca

O .>T.T.1

tn cl) zPe( C.)w

Ww

0.1 • E.*

Z

Z 0o--(

O0.4

.u;00

TABLE 7

SUMMARY OF UNCERTAINTIES IN THE RESULTS OF THEHUMAN HEALTH RISK ASSESSMENT

SITES 1 AND 3NAVAL SECURITY GROUP ACTIVITY


Uncertainty

PotentialMagnitude for

Over-Estimationof Risks

PotentialMagnitude for

Under-Estimationof Risks

PotentialMagnitude forOver or Under-

Estimationof Risks

Hazard Assessment and Analytical Data

Moderate

Moderate

Low

Sufficient samples may not have been taken to characterize themedia being evaluated.

Systematic or random errors in the chemical analysis may yielderroneous data.

The use of the maximum detected concentration in theestimation of the CDI/DAD.

Exposure Assessment

LowThe standard assumptions regarding body weight, exposureperiod, life expectancy, population characteristics, and lifestylemay not be representative of the actual exposure situations.

Toxicological Assessment

Moderate •Toxicological indices derived from high dose animal studies,extrapolated to low dose human exposure.

Risk Characterization

Moderate

Low

Low

Assumption of additivity in the quantitation of cancer riskswithout consideration of synergism, antagonism, promotion,and initiation.

Assumption of additivity in the estimation of systemic healtheffects without consideration of synergism, antagonism, etc.

Additivity of carcinogenic risks by individual exposurepathways (ingestion and dermal).

Notes:

Low - Assumptions categorized as "low" may effect risk estimates by less than one order of magnitude.

Moderate - Assumptions categorized as "moderate" may effect estimates of risk by between one and two orders ofmagnitude.

High - Assumptions categorized as "high" may effect estimates of risk by more than two orders of magnitude.

Source: Risk Assessment Guidance for Superfund, Volume 1, Human Health Evaluation Manual (Part A). (USEPA, 1989).

Celle Soren

'VD3S VNVOVS VOSN 's . n

0

Ou.t0zz0

coa 0V) 0

CO

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w

01

__J

Wa_ a-

0+• w —

(2) (aocc 0O00 (i) )-

.

1II

I

<Z<

LJ<

—J

of

0

LJ0

I I

Cr)

IIIIII

7̀1/9 n E_G

O

1 inch = 400 ft. Baker Enkonmental,

WELL LOCATION

LEGENDMW-S3-1

SITE 3NORTH STONE ROADDISPOSAL AREA

S3BWO1

40h;.• 0 200 400

APPROXIMATE AREA OF SITE

FENCE LINE

SOURCE: HOGGARD/EURE ASSOCIATES, APRIL 1993

FIGURE 3SITE PLAN

SITE 3

U.S. NAVAL SECURITY GROUP ACTIVITY, SABANA SECASABANA SECA, PUERTO RICO

MW-S1-1

x-x

047575PR

\\\^\ - NdW03^`odoa

DEPARTMENT OF THE NAVYATLANTIC DIVISION

NAVAL FACILITIES ENGINEERING COMMANDNorfolk Virginia

Under the:

LANTDIV CLEAN ProgramContract N62470-89-D-4814

Prepared By

• ,BAKER ENVIRONMENTAL, INC.

Coraopolis, Pennsylvania

FINAL

RECORD OF DECISIONSITE 2 - BUNKER 607 DISPOSAL AREA

SITE 4 - PISTOL RANGE DISPOSAL AREA

NAVAL SECURITY GROUP ACTIVITY.SABANA SECA, PUERTO RICO

CONTRACT TASK ORDER 0305

SEPTEMBER 3, 1997

Prepared For:

TABLE OF CONTENTS

Eng

LIST OF ACRONYMS AND ABBREVIATIONS vi

DECLARATION viii

1.0 SITE NAME, LOCATION, AND DESCRIPTION 1

2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 22.1 Site History 2

2.1.1 History - Site 1 32.1.2 History - Site 2 32.1.3 History - Site 3 42.1.4 History - Site 4 42.1.5 History - Site 5 42.1.6 History - Site 6 52.1.7 History - Site 7 6

2.2 Previous Investigations/Enforcement Activities 72.2.1 Previous Investigations 72.2.2 Enforcement Activities 10

2.3 Site Inspections/Remedial Investigation/Leachate Diversion-Feasibility Study 2.3.1 Site . Inspection - Sites 1 and 3 - (OU-3) 2.3.2 Remedial Investigation - Site 6 - (OU-2) 2.3.3 Leachate Diversion-Feasibility Study - Site 7

2.4 ROD Findings 2.4.1 Sites 1 and 3 - (OU-3) 2.4.2 Site . 6 - (OU-2)

2.5 Remedial Design/Remedial Action - Site 6 - (OU-2) 2.5.1 Design Activities 2.5.2 Remedial Construction Activities 2.5.3 Summary of Operations and Maintenance

4.0 SCOPE AND ROLE OF 111t, RESPONSE ACTION 18

5.0 SUMMARY OF SITE CHARACTERISTICS 185.1 Soil Contamination 18

5.1.1 Soil Contamination - Site 2 185.1.2 Soil Contamination - Site 4 19

5.2 Groundwater 195.2.1 Groundwater Contamination - Site 2 195.2.2 Groundwater Contamination - Site 4 20

10101112

13131313131415

2.6 Community Relations Activities 15

2.7 Site Close Out 15

2.8 Five-Year Review 16

3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION 16

TABLE OF CONTENTS(Continued)

124g4

5.3 Surface Water and Sediment 205.3.1 Surface Water and Sediments - Site 2 205.3.2 Surface Water Contamination - Site 4 205.3.3 Sediment Contamination - Site 4 21

6.0 SUMMARY OF SITE RISKS 22

6.1 Human Receptors 226.2 Ecological Receptors 236.3 Risks for Each Media 23

6.3.1 Soil Media - Site 2 236.3.2 Soil Media - Site 4

24

6.3.3 Groundwater Media- Site 2

246.3.4 Groundwater Media - Site 4

24

6.3.5 Surface Water and Sediments Media- Site 4

256.4 Uncertainty Analysis - Site 4

25

6.4.1 Environmental Media Sampling and Analysis 266.4.2 Chemical Transport and Fate Modeling

26

6.4.3 Toxicity Data


28

6.4.5 Risk Estimates

28

7.0 DESCRIPTION OF THE "NO ACTION" ALTERNATIVE 29

29 29


Responses 30

9.0 BIBLIOGRAPHY 30

TABLES

1 Contaminants of Potential Concern for Human Health Risk Assessment - Soil, SurfaceWater and Sediment Data Summary

2 Contaminants of Potential Concern for Human Health Risk Assessment - Groundwater DataSummary

3 Toxicity Values - Slope Factors4 Toxicity Values - RfD5 Exposure Pathways6 Summary of Pathway - Specific Risks - Summary Table of Carcinogenic Risks7 Summary of Pathway - Specific Risks - Summary Table of Noncarcinogenic Risks

8.0 RESPONSIVENESS SUMMARY8.1 Overview


iii

FIGURES

1 Vicinity Map2 Site Plan - Site 23 Site Plan - Site 44 Installation Restoration Site Locations

IV


ARAR

CERCLACOPCCPRCCRPCSF

DOD '

FFAFS

HIHQ

IASILCRIR

MCLmg/kg

NCPNPLNSGA

O&MOU

PREQB

QA/QC

RARABRAGSRBCRCRARDRfDRIROD

SARASISVOCs

applicable or relevant and appropriate requirement

Comprehensive Environmental Response, Compensation and Liability Actcontaminant of potential concernCaribbean Primate Research CenterCommunity Relations Plancancer slope factor

Department of Defense

Federal Facilities Agreementfeasibility study

hazard indexhazard quotient

Initial Assessment Studyincremental lifetime cancer riskInstallation Restoration

Federal Maximum Contaminant Levelmilligrams per kilogram

National Oil and Hazardous Substances Pollution Contingency PlanNational Priorities ListNaval Security Group Activity

operation and maintenanceoperable unit

Puerto Rico Environmental Quality Board

quality assurance/quality control

risk assessmentRestoration Advisory BoardRisk Assessment Guidance for SuperfundRisk-based ConcentrationsResource Conservation and Recovery Actremedial designreference doseremedial investigationRecord of Decision

Superfund Amendment and Reauthorization Actsite inspectionsemivolatile organic compound

TAL

Target Analyte ListTBC

To Be Considered

LIST OF ACRONYMS AND ABBREVIATIONS(Continued)

TCL

Target Compound List

• UCL

upper confidence limitUSEPA

United States Environmental Protection Agencylig/kg micrograms per kilogram

micrograms per liter

VOCs volatile organic compound

Sign ture (Commandin

Signa e (Chairman, PR Environni

Signature (Regiona dministra24.-... * oard)

n II)

DECLARATION

Site Name and Location

Site 2 - Bunker 607 Disposal AreaSite 4 - Pistol Range Disposal AreaNaval Security Group Activity, Sabana Seca, Puerto Rico

Statement of Basis and Purpose

This decision document presents the selected remedy for Site 2 and Site 4 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). Thisdecision is based on the administrative record file for Site 2, the Bunker 607 Disposal Area and Site 4, the Pistol RangeDisposal Area.



Declaration Statement•

This Record of Decision (ROD). documents that no action is necessary at Sites 2 and 4 to ensure protectionof human health and the environment. Because this remedy will not result in hazardous substancesremaining on site above health-based levels, the five-year review will not apply to this action.

In lieu of a Final Close Out Report, this ROD also documents that the U.S. Navy has completed allconstruction activities for all sites at the NSGA Sabana Seca Site in accordance with Close Out Proceduresfor National Priorities List Sites (OSWER Directive 9320.2-09). No action has been determined to benecessary for Sites 1, 2, 3,,and 4; the Navy has cleaned up Sites 5 and 6; and Site 7 will be addressed by theMunicipality of Toa Baja, the party responsible for Site 7 contamination. This decision documents that theNavy, U.S. Environmental Protection Agency (USEPA) and Puerto Rico Environmental Quality Board(PREQB) have determined that remedial actions for this site have been successfully implemented and nofurther response actions are necessary. Therefore, the site now qualifies for inclusion on the ConstructionCompletion List The PREQB conducted an inspection on May 9, 1997; and, the USEPA conducted, aninspection on July 17, 1997, and both agencies concur that all remedial action has been successfully executedby the Navy.

5 •-•-• /99,,Date

Date

Date f;r76'1,4)

vii

1.0 SITE NAME, LOCATION, AND DESCRIPTION

This Record of Decision (ROD) is for Operable Unit (OU) -1, Site 2, the Bunker 607 Disposal Area,

and Site 4, the Pistol Range Disposal Area, both of which are located in the south tract of Naval

Security Group Activity (NSGA) Sabana Seca. Other parts of the site are being addressed in

separate actions. OU-2 is for. Site 6, and OU-3 is for Sites 1 and 3. The 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 NSGA Sabana Seca site consists of a North and South tract together

occupying over 2,200 acres of land. NSGA Sabana Seca is a site being investigated for

environmental contamination under the Comprehensive Environmental Response, Compensation

and Liability Act of 1980 (CERCLA) and is included on United States Environmental Protection

Agency's (USEPA's) National Priority List (NPL).

NSGA Sabana Seca was originally a pineapple and grapefruit plantation known as the Stephenson

Place. The plantation was procured by the U.S. Navy during World War II. After the war, the

property was turned over to the U.S. Army. In 1951, the Navy'again assumed control and in 1952,

established the U.S. Naval Radio Station, Sabana Seca. In 1971, NSGA Sabana Seca was

established as an independent shore activity of the Navy. The facility has been operated as a

communications center continuously by the Navy since 1971.

Figure 1 presents a map of the south tract and the locations of Sites 2 and 4 within the south tract.

Site 2 is located within the north-central portion of the south tract approximately 500 feet west of

the intersection of Stone and Redman Roads. Site 4 is located in the southeastern portion of the

south tract, south of Stone Road and is surrounded on its north and west sides by Bataan Road. 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 Bayamon and Toa Baja Municipal Landfills and the U.S.

Department of Health and Human Services Research Facility.

The water table of the goundwater aquifer supply NSGA Sabana Seca is located approximately 50

to 70 feet below ground surface (bgs). The south tract of NSGA Sabana Seca is serviced by two

deep Base supply wells, at depths of 130 feet and 140 feet bgs, and are located in Buildings 10 and

22, east of the enlisted housing area and north of the officer housing area. The Base water supply

wells are located approximately 3,600 feet southeast of Site 2 and 3,000 feet northeast of Site 4. The

groundwater aquifer has not been impacted by on-site activity.

Figure 2 presents a site plan of Site 2 and shows the adjacent property uses. Site 2 covers an area

of approximately one half of an acre. Site 2 is bordered on the south by Stone Road and on the west

by an unnamed trail. The areas to the north and east of Site 2 are undeveloped and heavily

vegetated. The site is currently undeveloped and overgrown with vegetation.

Figure 3 presents a site plan of Site 4 and shows the adjacent property uses. Site 4 covers an area of

approximately 2 acres. The Initial Assessment Study (IAS) originally estimated the site to cover 5

acres. The site is surrounded by Bataan Road and a jeep trail. The. Base's perimeter fence borders

Site 4 on the north and west sides. The access road to the Bayamon/Toa Baja Landfill parallels

Bataan Road along the western perimeter of the site. The area around and within Site 4 is

undeveloped and heavily vegetated.

The topography at Sites 2 and 4 is relatively flat, and the areas are heavily vegetated. Drainage near

Site 2 generally flows to the northwest towards a swampy area. No free flowing surface waters

(streams) are located near Site 2. A large area of standing water immediately south of Bunker 607

has been observed on a seasonal basis. The standing water does not appear to flow off site, but

dissipates by evaporation or percolation into the underlying soil. Site 4 receives leachate, surface

water runoff and drainage from the adjacent municipal landfill. This leachate-contaminated runoff

collects in low areas within Site 4 and flows across and along Bataan Road and is referred to as

Site 7. Base personnel installed three culverts to channel the leachate flow under the road to the low

areas rather than over the road to minimize the potential for dermal exposure to Base personnel who

may use the road.

2.0 - SITE HISTORY AND ENFORCEMENT ACTIVITIES

2.1 Site History

An IAS conducted in 1984 identified and assessed sites posing a potential threat to human health or

the environment. The IAS identified seven sites:

Site 1 - South Stone Road Disposal Area

Site 2 - Bunker 607 Disposal Area

Site 3 - North Stone Road Disposal Area

Site 4 - Pistol Range Disposal Area

Site 5 - Wenger Road Disposal Area

Site 6 - Former Pest Control Shop

Site 7 - Leachate Ponding Area

The locations of these sites are shown on Figure 4.


According to the IAS report, Site 1 was the Base's landfill in operation from 1951 to 1960. During

that time, an estimated 3,300 tons of solid waste including residential waste, construction debris,

scrap metal, appliances, paint cans, and tree clippings were disposed at the site. The Public Works

Department collected solid waste twice a week using a dump truck, and deposited the solid waste

at Site 1. The solid waste was dumped directly onto the ground and left as mounds. Trenching and

daily cover were not employed as part of the disposal operations. No hazardous wastes were

reported to have been disposed at Site 1. Site 1 has remained inactive. The Navy has not removed

any wastes from Site 1. CERCLA investigation has determined that no action is necessary at this

site.


According to the IAS report, Bunker 607 was intermittently used by the Public Works Department

for materials storage from the 1960s to 1979. In 1979, the Public Works Grounds Maintenance

Division was ordered to clean out the bunker., Reportedly, approximately 500 one-gallon cans of

old paint intended to be used for the on-Base housing were disposed in the vicinity of Bunker 607.

CERCLA investigation has determined that no action is necessary at this site.


According to the IAS report, Site 3 was the Base's landfill in operation from 1960 to 1965. An

estimated 1,800 tons of solid waste including residential waste, construction debris, appliances,

scrap metal, scrap wood, and tree clippings were disposed at the site. The Public Works Department

collected solid waste twice a week using a dump truck, and deposited the solid waste at Site 3. The

solid waste was dumped directly onto the ground and left as mounds. Trenching and daily cover

were not employed as part of the disposal operations. No hazardous wastes were reported to have

been disposed at Site 3. Site 3 has remained inactive. The Navy has not removed any wastes from

Site 3. CERCLA investigation has determined that no action is necessary at this site.


According to the IAS, Site 4 was used as the Base's landfill from 1965 through possibly 1970. Prior

to its first use for solid waste disposal, the area may have been an orchard (based on 1950 and 1962

aerial photography from USEPA). Site 4 is named the Pistol Range Disposal Area because of its

proximity to the Base's pistol range.

While used as a disposal area, approximately 1,800 tons of waste including residential waste,

construction debris, appliances, scrap metal, and waste oil were reportedly disposed. According to

the IAS report, no hazardous wastes were reported to have been disposed at Site 4. No wastes were

removed from this site. CERCLA investigation has determined that no action is necessary at this

site.


According to the IAS, this site was reportedly used as a disposal site for mainly inert materials from

1980 through 1983. Materials disposed of at the site consisted of leaves and brush, cuttings, empty

drums, tires, wood and pallets, demolition debris, automobiles, mattresses, appliances, office

furniture, and other similar materials. During the time period this site was used for disposal, the

majority of solid waste was taken off Base for disposal by a contractor. Items disposed of at the site

were those items the contractor would not dispose of, primarily because of their size and weight.

In 1982, the Environmental Engineering Survey conducted by the Navy recommended that these

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materials be removed in order to "eliminate a point'of habitation for insects, rodents, and other

animals, some of which could be disease vectors." This would also eliminate the need to apply for

a landfill operation permit.

Cleanup of the site was conducted by the Navy's Transportation Division as an "in-house" operation.

Approximately 360 tons of large metal pieces and equipment, abandoned vehicles, appliances, and

general Base scrap and trash were removed. In addition, 30 to 40 unsuspected 55-gallon drums of

unknown material and two to three transformers were removed. The drums and transformers were

disposed of by Base personnel. Soil was removed to 16 feet below-grade, acceptable materials

buried, and clean soil replaced to the surrounding land grade. The materials removed were placed

in a nearby municipal landfill. Because Site 5 has been cleaned up, it does not pose a threat to

human health or the environment. Therefore, since this site had been previously remediated prior

to listing of NSGA Sabana Seca on the NPL, USEPA's July 19, 1994 letter to the Navy determined

that no further investigation of Site 5 will be required.


According to the IAS, 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 equipment 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 Base'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, seven, PRAMITOL,

and esteron (a mixture of 2,4-D and 7,4,5-1). 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 Base'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. The site was enclosed in a chain-

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link fence to limit public access. The fence gate was kept locked at all times. Warning signs were

posted in English and Spanish. This area along Stone Road is patrolled regularly by military police.

CERCLA investigation has resulted in a protective asphalt cap that has been constructed on this site

as documented in a ROD dated, September 20, 1996 and construction completed in April 1997.


Leachate from the nearby municipal landfill has been observed entering this wet marshy area, which

has been designated as Site 7. The municipal landfill, which is located directly adjacent to the Base

property, has been in operation since the early 1970s. The Navy excessed this land to the Puerto

Rico Land Authority in 1963. The municipal landfill covers approximately 69 acres and has

received the following types of wastes: pharmaceutical, residential, and industrial wastes; old cars;

tires; and appliances. NSGA Sabana Seca has used the municipal landfill for the disposal of wastes

since approximately 1972.

The municipal landfill is situated in an area of karst topography known as the "haystack" hills.

Surface runoff from this area enters the Base. The presence of wastes on top of the karst topography

of the municipal landfill creates the potential for contaminant migration via the groundwater.

Groundwater from the municipal landfill discharges to the swampy areas of the Base. Because of

the possibility of groundwater contamination from leachate migrating onto NSGA Sabana Seca

property, the municipal landfill poses a potential threat to human health and the environment.

The Navy has entered into an agreement with the Municipality of Toa Baja, municipal landfill

operators and PREQB to mitigate further impact to NSGA Sabana Seca from the municipal landfill

and will continue to monitor at Site 7 any contaminant migration from the municipal landfill.

The terms of this agreement are the following: The Municipality of Toa Baja will develop a

mechanism to control the leachate migrating onto NSGA Sabana Seca property. In addition, Toa

Baja will develop with NSGA Sabana Seca concurrence mechanisms to prevent the erosion at the

NSGA Sabana Seca's security road in the corner, where the storm water/leachate runoff from the

Bayomon/Toa Baja Landfill's access road discharges onto NSGA Sabana Seca's property. Toa

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Baja, as owner of the Bayamon/Toa Baja Landfill, will be responsible for funding and implementing

the agreed upon action.

The term of this agreement is from December 4, 1996 and will extend through post-closure

activities. PREQB will be expected to monitor contamination migration during this time.

2.2 Previous Investigations/Enforcement Activities

2.2.1 Previous Investigations

2.2.1.1 Initial Assessment Study

In 1984, an IAS was conducted for the Base. 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 secords and aerial

photographs, and conducted on-site inspections and personnel interviews.

The IAS report concluded that Site 2 did not pose a threat to human health or the environment,

despite the allegations of paint can disposal. No evidence of past operations or disposal was

identified at Site 2. No stressed vegetation, stains, leaks or odors were noted. Therefore, the IAS

report recommended no further investigations for Site 2.

The IAS report concluded that Site 4 did not pose a threat to human health or the environment. No

hazardous wastes were supposedly disposed in Site 4 and the site was found to be heavily vegetated

during the IAS field investigation. Therefore, the IAS report recommended no further investigations

for Site 4.

2.2.1.2 Confirmation Study

From 1985 through 1989, Hunter/ESE, Inc. conducted a Confirmation Study on Sites 6 and 7 as

recommended in the IAS report. Site 6, a former pesticide shop, has been addressed in a separate

ROD. Site 4 was investigated together with Site 7, a collection area for leachate from an off-Base

source, the Bayamon/Toa Baja Municipal Landfill. The Navy could investigate Site 4 and, at the

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same time, obtain analytical results regarding the municipal landfill leachate at Site 7. Confirmation

Studies were not conducted at Site 2.

During the Confirmation Study for Site 4/7, four monitoring wells were installed and sampled.

During Round 1, pentachlorophenol was found in all wells at concentrations ranging from

170 micrograms per liter (gg/L) to 460 gg/L. The inorganics, arsenic and chromium, were found

in all wells at concentrations ranging from 55.1 gg/L to 639 gg/L and 12.1 gg/L to 454 gg/L,

respectively. The high hits of pentachlorophenol and inorganics were found at comparable

concentrations in upgradient and downgradient wells of Site 4/7, and is therefore attributed to the

upgradient BayamOn/Toa Baja Municipal Landfill.

2.2.1.3 Site Inspection (SI)

From 1991 through 1994, Versar, Inc. conducted an SI for Sites 2 and 4. The purpose of the SI was

to assess the presence or absence of contamination associated with past Navy activities at these two

sites. The SI involved installing monitoring wells, and the collection and analysis of site soil,

groundwater, surface water and sediment.

SI Site 2

Because of the allegations of past paint can disposal, and apparent stressed vegetation potentially

resulting from past disposal practices was observed during a field reconnaissance, USEPA, Puerto

Rico Environmental Quality Board (PREQB) and the Navy determined additional investigations

should be conducted at Site 2.

The SI included a soil vapor study, a magnetometer survey, and the collection and analysis of soil

and groundwater samples. The samples were collected over four rounds. Three monitoring wells

were installed at Site 2. An area of potentially stressed vegetation south of the bunker at Site 2 was

identified during the SI (area where standing water has been seen).

The SI did not produce direct evidence of the disposal of 500 one-gallon cans of paint. The

magnetometer survey found no paint cans, only construction debris. The soil vapor survey identified

small areas with volatile organic compound (VOC) readings slightly in excess of background

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readings. Soil sample results contained low levels of VOCs and semivolatile organic compounds

(SVOCs) which may have been derived from paint or may be the result of sampling and/or

laboratory contamination. Groundwater sample results between S2GWO 1 SL (upgradient well) and

the other two wells were very similar providing further evidence that if the paint was disposed in the

area, it had not adversely affected the groundwater quality. Organic compounds detected in the

wells did not exhibit any trends in the types or concentrations detected from one round to another.

Organic compounds detected were at very low concentrations, slightly above the detection limit, and

different contaminants were detected in each round, if detected at all.

The areas of stressed vegetation appeared to be the result of the seasonal variation (i.e., a transition

in vegetation resulting from the area being under water for part of the year). During times of ponded

water, thick vascular vines and other aquatic plants occupy the area. As the area dries out, this

vegetation dies out and is replaced by grasses.

Based on these findings, the SI report concluded that past Navy practices have not impacted Site 2,

therefore, no further remedial action was recommended for the site.

SI Site 4

Because of the brevity of the IAS information and the municipal leachate • onded over Site 4, the

USEPA, the Navy and the PREQB determined additional investigations were needed at Site 4.

Between October 1991 and October 1993, Versar, Inc. conducted a SI for Site 4 to assess the

presence or absence of contamination associated with past activities at the site.

The SI included: monitoring well installation; a land survey; aquifer tests; and the collection and

analysis of soil, groundwater, surface water, and sediment samples. The samples were collected over

four rounds. Ten monitoring wells were installed at Site 4 during the SI.

The SI determined that Site 4 produced no observable flow of leachate of its own. Based on the

findings of the SI report, it was concluded that past Navy disposal practices have not impacted

Site 4. Therefore, no further remedial action was recommended for the site. The Navy is working

closely with the municipality in an effort to mitigate further impacts of the Bayamem/Toa Baja

Municipal Landfill on Navy and surrounding properties.

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2.2.2 Enforcement Activities

2.2.2.1 National Priorities Listing

NSGA Sabana Seca was proposed for inclusion on the National Priorities List on June 24, 1988 and

was included on October 4, 1989. The concern about the pesticides at Site 6 was the primary reason

NSGA Sabana Seca was proposed for the NPL.

2.2.2.2 Federal Facilities Agreement

On March 19, 1992, the Navy, USEPA, and the PREQB entered into a Federal Facilities Agreement

(FFA) for NSGA Sabana Seca. The primary purpose of the FFA was to ensure that environmental

impacts associated with past and present activities at the Base 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. This agreement established roles and responsibilities and improved communication

between the Navy, USEPA, and PREQB. It provided for the expeditions completion of all remedial

actions necessary to protect the public health, welfare, and the environment consistent with

CERCLA/Superfund Amendment and Reauthorization Act (SARA) and the National Oil and

Hazardous Substances Pollution Contingency Plan (NCP). Under the FFA, SIs were performed for

Sites 2 and 4.

• •2.3 Site. Inspections/Remedial Investigation/Leachate Diversion-Feasibility Study

All sampling and analysis, at all the sites at NSGA Sabana Seca were done in accordance with a

workplan prepared by the Navy and approved by USEPA and PREQB, and in accordance with the

USEPA Region II's CERCLA Quality Assurance Manual.

2.3.1 Site Inspection - Sites 1 and 3 - (OU-3)

Between 1993 and 1996, the 2 acre South Stone Road Disposal Area and the 11 acre North Stone

Road Disposal Area were sampled four times. The Navy performed a SI between December 1991

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and March 1997. At Site 1, carbon tetrachloride was detected twice in the groundwater in one well

above the Federal Maximum Contaminant Level (MCL) at 10 micrograms per liter (ttg/L). The final

SI report summarized all site analysis results.

On March 20, 1997, the Navy released the final SI report. The report provided an in-depth summary

and discussion of site sampling activities and a baseline risk assessment, qualitative and quantitative.

The report also concluded that since there was no unacceptable risk to human health or the

environment from the contamination of soil or groundwater at either site, no action was necessary.

•2.3.2 Remedial Investigation - Site 6 - (OU-2)

Between 1986 and 1993, the less than 1 acre site of the Former Pest Control Shop and adjacent areas

were sampled six times. The Navy performed a remedial investigation (RI) between. October 1991

and October 1993. Chromium was detected only once in the groundwater above the Federal MCL

at 119 pg/L. No pesticides were detected in the groundwater and surface water and those pesticides

detected in the soil and sediment were below Federal action levels.

Since there are no applicable or relevant and appropriate requirements (ARARs) established for the

cleanup of soil, chemical-specific To Be Considered (TBC) criteria were evaluated, instead. A

chemical-specific TBC of 500 micrograms per kilogram (µg/kg) 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. The final RI/feasibility

study (FS) report summarized all site analysis results.

On May 2, 1996, the Navy released the final RI/FS report. The report provided an in-depth

summary and discussion of site sampling activities, a human health and ecological risk assessment,

and an analysis of remedial alternatives. The report also concluded that since there was no

unacceptable risk to human health or the environment from the pesticide contamination of soil that

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has occurred at Site 6, no action was necessary. Nevertheless, the site is adjacent to a

playground/picnic area and the enlisted housing area. Therefore, as a reassurance to the public, the

Navy conservatively evaluated remedial alternatives that could limit the public's exposure to the

minimal contamination that may remain in the soil at Site 6. The RUFS report provided a detailed

analysis of capping; excavation, removal and off-site incineration; and no action remedial

alternatives.

23.3 Leachate Diversion-Feasibility Study - Site 7

Though the waste stream did not originate from Navy property, the Navy conducted a Leachate

Diversion/Feasibility Study to try to address the problem. The FS provided eight alternatives for

an interim treatment of the leachate entering Navy property. The alternatives evaluated were

considered impractical, including leachate collection, because of the location of NSGA Sabana Seca

in a rainforest, with the exception of an engineered wetlands, which would use phytoremediation

technologies. A treatability study of the engineered wetland technology was conducted as a result

of the FS. The study consisted of constructing a small scale wetland to evaluate the

implementability and effectiveness of this technology. Due to unforeseen changes in landfill

operations and the hydrology upgradient of the Base, and susceptibility of the engineered wetland

technology to drought conditions, the study was canceled. The final FS report summarized all site

analysis results.

On December 20, 1996, the Navy released the final FS report. The report provided an in-depth

summary and discussion of the eight alternatives, all of which were determined to be impractical as

the report has also determined that the leachate flowing onto Navy property at Site 7, a collection

area for leachate from an off-Base source, is from the Bayamon Municipal Landfill, the operation

of which could not be controlled by the Navy. Therefore, on February 27, 1997, the USEPA notified

the Navy that No Further Action was necessary and that a ROD would also not be required at Site 7.

The Nivy has entered into a Partnering Agreement with the landfill owners and operators, and

PREQB to further address landfill leachate at Site 7.

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2.4 ROD Findings

2.4.1 Sites 1 and 3 - (OU-3)

The Navy has prepared a No Action ROD for Sites 1 and 3 due to current site conditions,

environmental analyses and risk assessments. Though Sites 1 and 3 were formerly used as landfills,

no evidence exists to suggest that the soil or groundwater at either site poses a risk to human health

or the environment. Based on cleanup objectives at other Federal, State and Commonwealth

hazardous waste sites, this alternative will be protective of human health and the environment.

2.4.2 Site 6 - (OU-2)

On September 20, 1996, the Regional Administrator approved a ROD, which selected an asphalt

cap over the areas where pesticides were previously detected in the surface soils above TBC criteria.

The fence that is currently around portions of Site 6 will be removed. The area will be cleared and

grubbed. An eight-inch subbase layer of gravel will be placed in the area to be capped. A four-inch

layer of asphalt will be placed over the gravel subbase 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.

The cap will also eliminate the potential for any contact, human or environmental, with any

remaining minimal pesticide contaminated soils. Based on cleanup objectives at other Federal, State

and Commonwealth hazardous waste sites, as well as recommendations from the U.S. Centers for

Disease Control, this alternative will be protective of human health and the environment.

2.5 Remedial Design/Remedial Action - Site 6 - (OU-2)

2.5.1 Design Activities

On February 14, 1996, the Navy submitted the draft Remedial Design (RD). The RD was finalized

on May 2, 1996 and approved by the Navy on July 15, 1996. The Navy has paid all of the remedial

action costs and will assume responsibility for all of the operation and maintenance (O&M)

requirements, as required by CERCLA. The Navy awarded the contract to OHM Remediation

Services Corporation. The draft Remedial Action Workplan dated July 15, 1996, was received by

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USEPA on October 30, 1996, and approved by USEPA on December 19, 1996. The Remedial

Action Workplan was finalized by the Navy on January 14, 1997.

2.5.2 Remedial Construction Activities

The Site 6 construction project consisted of three primary tasks; site preparation, backfill and

compaction of subbase, and asphalt application.

On January 14, 1997, the Navy held a pre-construction meeting at the Base. The remedial action

field activities also commenced that day with clearing and grubbing. Preparation of Site 6 included

extensive clearing and grubbing activities, the removal of small trees and dense underbrush within

the fence, removal of crushed empty drums which formerly held drill soil cuttings, and the removal

of three large trees which were located slightly beyond the fenced perimeter but within the proposed

cap area. The cleared vegetation, including the felled trees outside of the fenced area, were

transported to the Base compost. Drums, which held soil cuttings from previous site inspections,

were emptied on site and the contents placed beneath the final cap. Clearing and grubbing of Site 6

was completed on February 5, 1997.

Backfill and compaction activities, which began on February 7, 1997 and ended on March 14, 1997,

were delayed due to heavy precipitation. Because of muddy conditions, saturated soil was excavated

and replaced with crushed stone backfill, which facilitated the backfill completion while reducing

the need for additional, more costly, select soil backfill.

Asphalt and site restoration occurred from April 3 to 11, 1997. A four-inch layer of asphalt was

applied over approximately 1,900 square yards, on top of the properly compacted subbase (>95%

compaction). A total of 180 cubic meters of topsoil was spread around the perimeter of the asphalt

cap, seeded and mulched.

On May 27, 1997, the Navy submitted a Remedial Action report to USEPA and PREQB signifying

successful completion of construction activities. Due to the contract modifications and weather

delays, the total remediation action contract cost ($261,000) exceeded the original $198,000

contract, by $63,000.

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A final construction inspection was performed on April 7, 1997, during which the asphalt cap was

approved and accepted. The remaining punch list items, consisting of final top soil application,

seeding, and mulching, was finalized and approved and accepted by the on-site representative for

the Navy on April 14, 1997. The PREQB conducted an inspection on May 9, 1997; and USEPA

conducted an inspection on July 17, 1997, and both agencies concur that all remedial action had been

successfully executed by the Navy.

2.5.3 Summary of Operations and Maintenance

Site 6 O&M activities to be performed include routine inspections of the asphalt cap, mowing, and

maintenance of the perimeter fence. The Navy has assumed all responsibility for O&M. The asphalt

cap will require minimal maintenance by the Navy. The life expectancy of an asphalt cap is

approximately 20 to 25 years with routine maintenance. A top sealant will be applied periodically

to the asphalt surface to prevent deterioration.


The Navy's community relations staff conducted an active campaign to ensure that the residents

were well-informed about the activities at the Base. Community relations activities included: Site

Information/Photograph Albums; Site Brochures/Fact Sheets; a Community Relations Plan;

Technical Review,Committee/Restoration Advisory Board (RAB) meetings; and Public Awareness

Sessions.

2.7 Site Close Out

This No Action ROD, in lieu of a Final Close Out Report, documents that the U.S. NaVy has

completed all construction activities for the NSGA Sabana Seca site in accordance with Close Out

Procedures for National Priorities List Sites (OSWER Directive 9320.2-09). No action has been

determined to be necessary for Sites 1, 2, 3, and 4; the Navy has cleaned up Sites 5 and 6; and Site 7

will be addressed by the Municipality of Toa Baja, the party responsible for Site 7 contamination.

This decision documents that the Navy, USEPA and PREQB have determined that remedial actions

for this NSGA Sabana Seca site have been successfully implementedand no further response actions

are necessary. Therefore, the NSGA Sabana Seca site now qualifies for inclusion on the

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Construction Completion List. The PREQB conducted an inspection on May 9, 1997; and, the

USEPA conducted an inspection on July 17, 1997, and both agencies concur that all remedial action

has been successfully executed by the Navy.

All cleanup actions specified in the ROD for. Site 6 have been implemented. The asphalt cap

provides further assurance that Site 6 poses no threats to human health or the environment. The only

remaining activity to be performed is O&M that the Navy has guaranteed.

USEPA will issue a Notice of Intent to Delete NSGA Sabana Seca site from the NPL.

A bibliography of all reports relevant to the completion of this NGSA Sabana Seca site under the

Superfund program is attached. These documents are available by calling the NSGA Sabana Seca

Public Affairs Officer at (787) 261-8307.


Because no hazardous substances remain at the site above health-based levels, a five-year review

does not apply to the NSGA Sabana Seca site.

3.0 . HIGHLIGHTS OF COMMUNITY PARTICIPATION

The public participation requirements of CERCLA/SARA and the NCP have been met by the

following activities.

RAB members, which include representatives from regulatory agencies, the Navy and the local

community, have participated in the review of draft documents and have worked together to fmalize

these documents.

A Community Relations Plan (CRP) for all sites at the Base was prepared in 1991 and is available

in English and Spanish. The CRP is part of the community right-to-know process. The primary

purpose of the CRP is to provide information and to promote constructive, effective communication

between the Base and the surrounding community.

16

Although Puerto Rico is a Commonwealth of the United States, a large percentage of the population

is not fluent in English; Spanish is the main language of Puerto Rico. Therefore, the Navy had

pertinent summary documents translated into Spanish.

The Administrative Record, which contains all documents that form the basis for the selection of

a response action, is maintained at the Base library and at the Jaime Fonadella Garriga Public

Library in Toa Baja, Puerto Rico. The notice of availability for the Administrative Record for this

Federal facility was first published on May 12, 1996 and May 13, 1996 in local newspapers. The

English version of the public notice was published in the San Juan Star; the Spanish version was

published in the Nuevo Dia.

The Proposed Plan for these two sites was released to the public (i.e., were placed in the

Administrative Record) on June 17, 1997. The public notice indicating once again the availability

of the Administrative Record for the facility and specifically indicating the availability of the

Proposed Plan for review was published on June 15, 1997 and June 16, 1997 in local newspapers.

The English version of the notice was published in the San Juan Star, the Spanish version was

published in the Nuevo Dia. The Proposed Plan, ROD, the Site Information/Photograph Album, fact

sheets and the Administrative Record's introduction are available in English and Spanish.

As indicated in the public notice, a public comment period was held from June 17, 1997 to July 17,

1997. The public comment period provided the public the opportunity to review the Administrative

Record and comment on the Proposed Plan. The public notice also requested public attendance to

the public awareness session which would be held on July 17, 1997. There was little public interest

in the Proposed Plan. The Navy received no requests for a time extension to the public comment

period.

On July 17, 1997, the Navy held the public awareness session in lieu of a public meeting even

though there had been no public request for a meeting. The public awareness session was held to

respond to public questions, if any, and to accept oral or written public comments on the Proposed

Plan. Had there been public comments received, a response to these comments would have been

included in the Responsiveness Summary section within this ROD. Fact sheets and a Site

Information/Photograph Album, both in English and Spanish, were provided during the public

awareness session to help the public understand the sites better. Navy representatives fluent in

17

English and Spanish and knowledgeable on this project were present at the public awareness session

to answer questions.

4.0 SCOPE AND ROLE OF THE RESPONSE ACTION

The "No Action" alternative has been selected for Sites 2 and 4. Current site conditions,

environmental analyses, and risk assessments indicate that no action is warranted at Site 2 or Site 4.

Though Sites 2 and 4 were formerly used as disposal areas, the risk to human health and the

environment is low. No evidence exists to suggest that the soil, groundwater, surface water, or

sediment at either site poses a risk to human health or the environment. No further studies will be

conducted at these sites. No previous removal or interim remedial actions have been conducted at

Sites 2 and 4, and no future remedial actions are proposed at these sites.

5.0 SUMMARY OF SITE CHARACTERISTICS

This section of the ROD presents an overview of the nature and extent of contamination at Sites 2

and 4 with respect to the known or suspected sources of contamination, types of contamination, and

affected media. Based upon the Confirmation Study, the SI, and the site history, the source of

contamination at Site 2 involves its reported former use as a paint disposal area. The source of

contamination at Site 4 involves its former use as a Base landfill. No additional sources of

contamination were identified.

5.1 Soil Contamination


As part of the SI for Site 2, soil sampling was conducted within the area of stressed vegetation

identified immediately south of the bunker.

Round 1 surface soil samples were collected in April 1992 and analyzed for lead (20 samples).

Detected lead levels ranged from 0.51 milligrams per kilogram (mg/kg) to 35.1 mg/kg.

18

A second round of soil samples was collected in April 1993. Six samples were collected and

analyzed for full Target Compound List (TCL) organic compounds and Target Analyte List (TAL)

inorganic compounds. Trace level organics were detected during the second sampling round.

Several inorganic compounds were detected in the second round of soil samples. Based on a

comparison with background sample concentrations, estimated lead levels ranged from 1.5 mg/kg

to '11.4 mg/kg, while background levels ranged from 4.2 mg/kg to 94.9 mg/kg.


During the SI for Site 4, soil sampling was conducted during Rounds 1 and 2. Four samples were

collected during Round 1 at the 0 to 3 foot depth range. During Round 2, soil samples were

collected from four locations at depths of 0 to 3 feet and 3 to 6 feet. The Round 1 and 2 samples

were analyzed for TCL organic compounds and TAL inorganic compounds.

Organic compounds were detected at very low levels during the two rounds of sampling at Site 4.

Inorganic compounds were detected that were considered elevated when compared to background

levels. Inorganic compounds detected include aluminum (17,800 mg/kg); antimony (8.8 mg/kg);

chromium (105 mg/kg); cobalt (20.4 mg/kg); and manganese (2,170 mg/kg).

5.2 Groundwater


Groundwater samples were collected from Site 2 during three rounds of sampling (Rounds 2, 3, and

4). There were no Round 1 SI groundwater data because monitoring wells had not been installed.

During each round, groundwater samples were collected from three Site 2 wells, two public wells,

and two background wells. The samples were analyzed for TCL organics and TAL inorganics.

The SVOC, pentachlorophenol, was detected in one of the Round 2 samples, at 38 gg/L.

Pentachlorophenol was found once and not confirmed in two other rounds of sampling. Several

inorganic compounds were detected in the Round 2 samples. Based on a comparison with

background sample concentrations, estimated lead levels ranged from 2.5 pg/L to 2.7 gg/L;

background levels ranged from 4.1 gg/L to 5.3 gg/L.

19

The results from the Round 3 groundwater samples indicated that organic compounds were not

present in the ,samples. Lead was detected at estimated concentrations ranging from 1.2 Itg/L to

2.6 ug/L; background levels were estimated at 3.1 ug/L and 3.8 p.g/L.

The results from the Round 4 groundwater samples indicated several inorganics. Lead was not

detected in the samples analyzed.

Although the SVOC, pentachlorophenol, was detected once, organic contamination was not

confirmed by additional sampling. Inorganic concentrations were found to be comparable to

background.


Groundwater samples were collected from Site'4 during four rounds of sampling. The samples were

analyzed for TCL organics and TAL inorganics. Several VOCs and SVOCs were found at very low

concentrations during all four rounds, while inorganic concentrations were found to be comparable

to background concentrations during the four rounds of sampling. Analytical results from within

Site 4 were compared to upgradient results. This comparison indicated that Site 4 may be

contributing slightly to downgradient contamination, but the majority of metal and VOC

contamination is due to an off-site source, most likely, the 13ayamOn/Toa Baja Landfill.

Surface Water and Sediment

5.3.1 Surface. Water and Sediments - Site 2.

Surface water and sediment samples were not collected at Site 2 because there are no surface water

features at the site.

5.3.2 Surface Water Contamination - $ite 4

Surface water samples at Site 4 were collected from drainage ditches and the leachate ponded areas

when water was available.

20

Surface water samples were collected during. Rounds 1, 2 and 4 of the SI. Four surface water

samples were collected in Rounds 1 and 4; two surface water samples were collected in Round 2.

The samples were analyzed for TCL organics and TAL inorganics. Several inorganics (aluminum

and manganese) were detected at concentrations above background (upgradient) levels.

Due to drought conditions, only two samples were collected from areas which contained enough

water to obtain a sample during Round 2 and no surface water was collected during Round 3.

Surface water samples were collected to assess the impact from the municipal leachate flowing onto

Site 4. Surface water at Site 4 is comprised of the leachate-contaminated runoff flowing from the

adjacent municipal landfill. Surface water contamination was not thought to be caused by Site 4.

Additional sampling would not have further defined contamination at Site 4.

The detected organic compounds were found at low concentrations. Several inorganics were

detected above background levels.

With respect to the Round 4 surface water samples, the only organics detected were two pesticides

(alpha-BHC, and beta-BHC). Several inorganics were detected above background levels. The SI

attributed the surface water contamination to the BayamOn/Toa Baja Municipal Landfill.

5.3.3 Sediment Contamination - Site 4

Sediment samples at Site 4 were collected from the same location as the surface water samples

(i.e., in the drainage ditches and the leachate ponded areas).

Four sediment samples were collected and analyzed for TCL organics and TAL inorganics during

Round 1. The inorganics detected were in the range of background/upgradient levels. Sediment

samples were not collected during Rounds 2, 3, and 4 because sediment contamination was thought

to be caused by the adjacent municipal landfill, not by Site 4. Additional sampling would not have

further defined contamination at Site 4.

21

6.0 SUMMARY OF SITE RISKS

Based on the results of the site inspections, a risk assessment (RA) was conducted for Site 4.

Because no direct evidence of contamination was found, no RA was conducted for Site 2. The RA

was conducted in accordance with the Risk Assessment Guidance for Superfund (RAGS), Part A,

Human Health Evaluation Manual (USEPA, 1989). The RA considered the most likely routes for

potential exposure for both current and future exposure scenarios. To calculate the risks, the

incremental lifetime cancer risks (ILCR) were calculated for different scenarios. The ILCR is a

number that represents the potential cancer risk that is above the background cancer risk to

unexposed individuals. Potcntial carcinogenic risks were evaluated using the cancer scope factors

(CSFs) developed by USEPA for the contaminants of potential concern (COPCs). Table 1 contains

a summary of the COPCs for soil, surface water and sediment; and Table 2 contains a summary of

the COPCs for groundwater. CSFs (see Table 3) have been developed for estimating excess lifetime

cancer risks associated with exposure to potentially carcinogenic chemicals. A CSF is multiplied

by the estimated chemical intake to generate an upper-bound estimate of the excess lifetime cancer

risk associated with exposure to the compound at that intake level. A number called the hazard

quotient (HQ) is used to determine the non-carcinogenic effects of chemical exposure. The hazard

index (HI) is obtained by adding the HQs for all chemicals, within a medium, that impact a

particular receptor population. The HI number is compared to unity (1.0).

The HI is a representation of the chronic daily intake divided by a safe or reference dose (REED). RfD

Table 4) is an estimate of a daily exposure level for the human population, including sensitive

subpopulations, that is likely to be without an appreciable risk of adverse effects during a lifetime.

Ratios less than one indicate that non-carcinogenic health effects are unlikely. Ratios greater than

one indicate the potential for the occurrence of adverse non-carcinogenic health effects.

Human Receptors

The human receptors (see Table 5 - For Exposure Pathways) in the vicinity of Sites 2 and 4 include

both on-Base and off-Base personnel. The Base housing areas are approximately 2,500 feet from

both sites. The distance to the nearest potable water well is approximately 2,000 feet at the

Department of Health and Human Services Caribbean Primate Research Center (CPRC). The closest

22

off-Base residence is in the village of Sabana Seca, approximately 1 mile to the northeast of both

sites (see Tables 6 and 7 - For the Summary of Pathway - Specific Risks).

6.2 Fcological Receptors

The area around Sites 2 and 4 is heavily vegetated and consists of limestone hills (haystack) and

sinkholes. The haystack hills are inhabited by the Puerto Rican Boa, the White-crowned Pigeon, and

various plant species that are listed as endangered/threatened species. No ecological RA was

conducted at either site because these types of assessments are not included in Federal guidance for

conducting SIs.

6.3 Risks for Each Media

The following paragraphs describe the risks for each media at Sites 2 and 4.

6.3.1 Soil Media - Site 2

In lieu of Federal soil criteria/standards, the detected concentrations of the compounds in the soil

samples were compared to USEPA Region III Risk-based Concentrations (RBCs). RBCs are

conservative benchmarks developed by Region III toxicologists for comparing results of analytical

data. The RBCs lists contaminant concentrations in soil for typical (i.e., residential, industrial) land

uses that are expected to be safe for lifetime exposure.

In the 1992 samples, lead was detected at concentrations well below the Federal soil screening levels

for lead of 400 mg/kg. In the 1993 samples, several inorganic compounds were detected. Lead

levels were once again below the federal soil screening level ranging in concentration from 1.5 to

11.4 mg/kg.

The results from the SI soil samples did not indicate any direct evidence of the reported disposal of

the 500 one-gallon cans of paint within the Site 2 area. The contaminant concentrations were below

Federal action levels.

23

6.3.2 Soil Media - Site 4

The SI determined that the Pistol Range Disposal Area produced no observable flow of leachate of

its own and was impacted by contamination from the off-site municipal landfill due to the visible

leachate flow. Relatively low concentrations of organic chemicals were detected in the soil;

however, due to the presence of the leachate stream on site, and uncertainty regarding the location

of leachate flows and ponding in the past, these contaminants can not be attributed to Site 4. As a

conservative approach, the RA performed under the SI assumed all soil contamination was related

to Site 4. The RA results indicated that the evaluated soil exposures did not generate a significant

carcinogenic risk or non-carcinogenic hx'ard for either current or potential future use scenarios.

Therefore, the results from the SI soil samples did not indicate any direct evidence of impact to

human health or the environment from Site 4.

6.3.3 Groundwater Media- Site 2

The concentrations of the detected organic compounds were below established groundwater criteria

(the Federal Drinking Water Standards -MCLs) with the exception of the one detection of

pentachlorophenol that was not confirmed in other wells and two other sampling rounds.

Several inorganic compounds were detected in the groundwater samples collected during the SI.

The detected concentrations of the inorganics were considered not to pose any threat to human

health or the environment.•

Therefore, the results from the SI groundwater samples did not indicate any direct evidence of the

reported disposal of the 500 one-gallon cans of paint within the Site 2 area Because no direct

evidence of contamination was found, no RA was conducted.

6.3.4. Groundwater Media - Site 4

M summarized in the SI report, groundwater analytical data typically showed higher concentrations

of organics and inorganics upgradient of Site 4. The SI report also concluded that while Site 4 may

contribute very slightly to downgradient contamination, the bulk of contaminants detected can be

attributed to the upgradient municipal landfill. The off-Base landfill'is considered responsible for

24

•

•

persistent detections of organics in samples from up-gradient monitoring wells at concentrations

exceeding MCLs.

In conducting the RA for Site 4, primary exposure pathways were identified for the groundwater.

They include future ingestion of drinking water, and inhalation and dermal absorption while

showering for residential children and adults, and on-site adult workers.

6.3.5 Surface Water and Sediments Media- Site 4

The SI RA for Site 4 determined that surface water and sediment generated negligible risks for

current and future use scenarios. The estimated risks were higher in the upgradient data group for

surface water than for the site as a whole. Risks were calculated to be slightly higher in the

downgradient data group for sediment; however, this may be due to sediment transport, rather than

an indicator of contamination resulting from Site 4. Carcinogenic risks were within the acceptable

range of 104 to 10' (one in ten thousand to one in one million). These data indicate that the

upgradient Bayamem/Toa Baja Landfill is primarily responsible for the environmental degradation

present at the site.

6.4 Uncertainty Analysis - Site 4

Despite recent advances in RA methodology, uncertainties are inherent in the RA 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 uncertainly. Sources of uncertainty in this RA, as

in any RA, include:

Sampling and analysis

Chemical transport and fate modeling

Toxicity data

Exposure assessment

Risk estimates

25

6.4.1 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's

procedures. Data were subsequently reviewed in a data validation process; however, current

analytical procedures may not identify all potentially haznrdous contaminants at a site, and analytical

errors may have occurred despite stringent quality assurance/quality control (QA/QC) procedures.

In conducting this RA, it was assumed that the reported chemical concentrations were representative

of actual site conditions.

6.4.2 Chemical Transport and Fate Modeling

The 95th percentile upper confidence limit (UCL) (or maximum) concentrations of COPCs found

in soil, surface water, sediment, and groundwater at and around Site 4 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 media. It has-been conservatively assumed that the concentrations observed at Site 4

will remain relatively unchanged with time because, with the exception of the VOCs and SVOCs,

all COPCs are relatively persistent and immobile.

6.43 Toxicity Data

•

The available scientific data on subchronic and chronic toxic effects in humans for the chemicals

of concern found at Site 4 are limited. Consequently, varying degrees of uncertainty surround the

assessment of adverse health effects in potentially exposed populations. Sources of uncertainty for

toxic effects in humans include:

Use of dose-response data -from experiments on homogenous, sensitive animal

POPULATIONS to predict effects in heterogenous human populations with a wide

range of sensitivities;

,26

• 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 frequent necessity to extrapolate results of short-term or

chronic animal studies to humans exposed over a lifetime has inherent uncertainty. In order to adjust

for many of these uncertainties, USEPA often adjusts the 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. Inadequate knowledge of the validity and accuracy of the linearized multistage model may

increase the uncertainty and the tendency to overestimate actual cancer risks.

27

When dealing with exposures to chemical mixtures, USEPA assumes dose additivity and does not

account for potential synergisms, antagonisms, differences in target organ specificity, of

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 RID derivations for single chemicals may compensate for any unknown effects of synergistic

exposures.


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 4 media and the frequencies and durations of

these contacts. The exposure parameters used in this assessment were largely based on USEPA's

RAGS (USEPA, 1989a) and Exposure Factors Handbook (1989b), 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 Headquarters and USEPA Region II 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 4.

6.4.5 Risk Estimates

The actual risks associated with a given exposure result from a complex set of interactions, which

are not understood and cannot be quantitatively 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 parcinogenesis. In addition, potential

differences in sensitivities of various subpopulations to various chemicals are poorly understood at

this time.

28

Because there may be small individual uncertainties at each step of the RA process, these

uncertainties may become magnified in the final risk characterization. The final quantitative

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 consequences of uncertainty, USEPA 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 USEPA guidance at the time it was prepared. It is likely that RA methods and the

data identifying and quantifying the toxicity of chemicals will improve with time. Consequently,

unsuspected hazards at this site may be identified at a later date. This assessment was based upon

available data, using currently available RA methodology.

7.0 DESCRIPTION OF THE "NO ACTION" ALTERNATIVE

The selected remedial action for Sites 2 and 4 is "no action". No adverse health effects could be

attributed to the contaminants detected in the soil, surface water, sediments and groundwater at

Site 2 or Site 4, therefore, no action is deemed appropriate. "No action" involves taking no further

investigative or remedial actions at the sites and leaving them as they currently are. There are no

costs associated with the "no action" alternative.

8.0 RESPONSIVENESS SUMMARY

8.1 Overview

A public comment period was held from June 17, 1997 through July 17, 1997. A public awareness

session, in lieu of a public meeting, was held on July 17, 1997. No public comments were received.


A record review of the NSGA Sabana Seca files indicates that the community involvement centers

mainly on social activities, including the community outreach programs and Base/community clubs.

29

There are two communities at Sabana Seca: the Base English speaking community and the

surrounding Spanish speaking community. The Base has actively pursued participation from both

communities.

For all the sites at the Base, community relations activities to date are summarized below:

Prepared a Community Relations Plan in English and Spanish.

• Prepared Site Information/Photograph Albums in English and Spanish during the

public awareness sessions.

Prepared Fact Sheets in English and Spanish during the public awareness sessions.

Established the Administrative Record/Information Repository at two locations -

(one location was on-Base and one location was off-Base).

Held Technical Review Committee/RAB meetings to review the status of the

remedial activities on the Base.

Released Proposed Plans in English and Spanish for public review.


Responses

No comments were received during the public comment period, and no comments were received

from those who-attended the public awareness session. A representative from USEPA and PREQB

attended the public awareness session.

9.0 BIBLIOGRAPHY

This bibliography presents a listing of all of the documents that were prepared as part of the

Installation Restoration (IR) program at NSGA Sabana Seca. The documents are listed by site in

chronological order.

30

Sites I and 3

NSGA Sabana Seca - Basewide

• Initial Assessment Study of Naval Security Group Activity. Sabana Seca And Naval

Communications Base. Puerto Rico. Greenleaf, Telesca/Ecology and Environment.

September 1984.

• ,Remedial Investigation - Interim Report to Determine Dispersion and Migration of

Specific Chemicals, NSGA Sabana Seca, Puerto Rico. Draft. Hunter/ESE, Inc.

January 1989.

Final Work Plan. Remedial Investigation/Feasibility Study for the Naval Security

Group Activity. Sabana Seca. Puerto Rico. Versar, Inc. August 1991.

• Site Information/Photograph Album. Naval Security Group Activity. Sabana Seca,

Puerto Rico. Draft. Baker Environmental, Inc. May 31, 1996.

Site Information/Photograph Album. Naval Security Group Activity. Sabana Seca,

Puerto Rico. Draft Final. Baker Environmental, Inc. July 15, 1996.

Work Plan Addendum for Sites I and 3. Site Inspection. NSGA Sabana Seca.

Final. Baker. Environmental, Inc. February 1993.

Site Inspection Report for Site 1 South Stone Road Disposal Area. Naval Security

Group Activity. Sabana Seca. Puerto Rico. Draft Final. Baker Environmental, Inc.,

October 1994.

Site Inspection Report for Site 3 North Stone Road Disposal Area. Naval Security

Group Activity. Sabana Seca, Puerto Rico. Draft Final. Baker Environmental, Inc.,

October 1994.

31

• Work Plan Addendum for Sites 1 and 3. Expanded Site Inspection. NSGA Sabana

Seca. Final. Baker Environmental, Inc. March 1996.

Expanded Site Inspection for Sites 1 and 3. Naval Security Group Activity. Sabana

Seca. Puerto Rico. Final. Baker Environmental, Inc., March 1997.

• Superfund Proposed Plan. Site 1 - South Stone Disposal Area. Site 3 - North Stone

Road Disposal Area. U.S. Naval Security Group Activity. Sabana Seca. Puerto

Rico. Final. Baker Environmental, Inc., June 1997.

Record of Decision. Site 1 - South Stone Disposal Area. Site 3 - North Stone Road

Disposal Area. U.S. Naval Security Group Activity, Sabana Seca. Puerto Rico.


Sites 2 and 4

Site Inspection/Risk Assessment Report, Bunker 607 Area (Site 2). Naval Security

Group Activity. Sabana Seca. Puerto Rico. Final. Versar, Inc. December 1996.

• Site Inspection/Risk Assessment Report. Pistol Range Disposal Area/Leachate

Ponding Area. Site 4/7. Naval Security Group Activity. Sabana Seca. Puerto Rico.

Final. Versar, Inc. December 1996.

Superfund Proposed Plan. Site 2 - Bunker 607 Disposal Area. Site 4 - Pistol Range


Final. Baker Environmental, Inc. June 1997.

Record of Decision. Site 2 - Bunker 607 Disposal Area. Site 4 - Pistol Range

Disposal Area. U.S. Naval Security Group Activity. Sabana Seca, Puerto Rico.


32

Site 5

• USEPA issued No Further Response Action Planned concurrence letter. July 1994.

Site 6

• Superfund Proposed Plan, Site 6 - Former Pest Control Shop, U.S. Naval Security

Group Activity. Sabana Seca. Puerto Rico. Baker Environmental, Inc.,

March 1996.

Remedial Investigation/Feasibility Study, Pest Control Shop, Site 6, Naval Security

Group Activity. Sabana Seca. Puerto Rico. Versar, Inc. May 1996.

• Final Design. Installation of Asphalt Cap. Site 6. Former Pest Control Shop. U.S.

Naval Security Group Activity. Sabana Seca, Puerto Rico. Baker Environmental,

Inc. May 1996 (signed in July 1996).

Record of Decision. Site 6. Former Pest Control Shop. Naval Security Group

Activity, Sabana Seca. Puerto Rico. Final. Baker Environmental, Inc.

September 1996.

Work Plan for Installation of Asphalt Cap. Site 6. Former Pest Control Shop. NSGA

Sabana Seca. Final. OHM, Inc. January 1997.

Remedial Action Report for Asphalt Cap at Site 6. Former Pest Control Shop,

NSGA Sabana Seca. Final. OHM, Inc. August 1997

• Leachate Diversion/Feasibility Study. Naval Security Group Activity. Sabana Seca,

Puerto Rico. Final. Baker Environmental, Inc. December 1996.

• USEPA issued No Further Response Action Planned concurrence letter,

February 1997.

33

TABLE 1

CONTAMINANTS OF POTENTIAL CONCERN FOR HUMAN HEALTH RISK ASSESSMENTSOIL, SURFACE WATER AND SEDIMENT DATA SUMMARY -

95% UPPER CONFIDENCE LIMIT (UCL) OR MAXIMUMSITE 4/7, SABANA SECA, PUERTO RICO

Constituent Soil (mg/kg)

Surface Water (mg/L) Sediment (mg/kg)Upgradient of

Site 4/7Site 4/7 onand off site

Upgradient ofSite 4/7

Site 4/7 onand off site

Volatile Organic CompoundsAcetone 1.35E-02 1.40E-02 2.87E-02 -- 1.76E-022-Butanone -- 8.76E-03 6.87E-03 - --

Toluene 6.58E-03 - - --Semivolatile Organic Compounds

Benzoic Acid -- - 9.00E-03 --Bis(2-ethylhexyl)phthalate

-- 8.00E-03 7.89E-03 3.60E+00 2.41E+01

Butylbenzylphthalate -- - 5.80E-01 5.80E-01Di-n-octyl phthalate 8.10E-02 - - 1.99E+00Phenol -- 5.00E-03 5.00E-03 -- --Nitrobenzene -- -- 9.00E-03 --

Pesticidesalpha-BHC 1.20E-04 9.08E-05 -- --beta-BHC 1.33E-04 1.16E-04 -

gamma.-BHC (Lindane) . - 1.04E-04 8.18E-05 - --

Endosulfan I 7.90E-05 6.13E-05 -PCBs

Aroclor 1248 . I 1.27E-01 I - I1 -- --Herbicides

2,4-D 2.32E-03 1.49E-03 - -

Dichloroprop -- 2.60E-04 1.74E-03 -- -

Silvex - 1.13E-01 5.63E-02 --Inorganics and Cyanide

Aluminum 1.51E+04 8.86E+00 4.96E+00 ....

Antimony 7.94E+00 2.71E-02 2.71E-02 - --Arsenic 3.53+00 5.37E-02 3.84E-02 3.59E+01 4.08E+01Barium -- 2.66E-01 2.11E-01 - --

Beryllium -- 1.70E+00 1.90E+00Cadmium . -- - - 1.80E+00 1.86E+00Calcium -- - 1.23E+05 1.31E+05Chromium 9.31E+01 7.68E-02 5.39E-02 1.08E+02 1.40E+02Cobalt 1.24E+01 1.39E-01 8.37E-02 -- 1.46E+01Copper - 1.69E-01 1.05E-01 -- --Iron 3.92E+04 1.96E+01 1.29E+01 -- 6.34E+04

TABLE 1 (Continued)

CONTAMINANTS OF POTENTIAL CONCERN FOR HUMAN HEALTH RISK ASSESSMENTSOIL, SURFACE WATER AND SEDIMENT DATA SUMMARY -


Constituent Soil (mg/kg)

Surface Water (mg/L) Sediment (mg/kg)





Inorganics and Cyanide (continued)

Lead -- 222E-02 1.76E-02 — —

Mapesium -- 4.19E+01 4.07E+01 -- --

Manganese 1.21E+03 5.58E-01 5.38E-01 9.76E+02 9.76E+02

Mercury -- 5.07E-04 3.37E-04 -- --

Nickel -- 3.56E-01 2.28E-01 -- --

Potassium 4.85E+02 9.99E+02 6.46E+02 1.63E+03 1.97E+03

Selenium 2.20E-03 3.00E-03 -- --

Sodium 2.09E+03 1.35E+03 1.07E+03 1.07E+03

Vanadium -- 8.42E-02 6.81E-02 —

Zinc -- 2.78E-01 1.94E-01 --

Cyanide 1.45E-01 1.73E-01 --

Notes:

mg/kg = milligrams per kilogram

TABLE 2

CONTAMINANTS OF POTENTIAL CONCERN FOR HUMAN HEALTH RISK ASSESSMENTGROUNDWATER DATA SUMMARY -,


Constituent

Blanket DepositGroundwater (mg/L)

Shallow LimestoneGroundwater (mg/L)


Site 4/7 on and offsite



Volatile Organic CompoundsAcetone 2.40E-02 9.51E-03 4.80E-02 --2-Butanone 8.29E-03 --Benzene. -- -- 2.22E-02 9.07E-03Carbon Disulfide -- -- 6.00E-03Chloroform 1.30E-02 7.93E-03 --

Methylene Chloride -- 3.00E-03 --

Tetrachloroethene -- 5.00E-03 9.00E-03 9.42E-03Semivolatile Organic Compounds

Bis(2-ethylhexyl)phthalate

3.00E-02 2.99E-02 6.85E-02 4.59E-02

Di-n-octyl phthalate 6.00E-03 6.00E-03 4.00E-03 4.00E-03

Phenol -- 2.50E-02 2.36E-02Pesticides

delta-BHC I I 1.70E-04 I 5.35E-05Herbicides

2,4-D 2.10E-04 1 1.18E-04Inorganics and Cyanide

Aluminum -- 5.33E+01 --

Antimony 7.27E-02 8.03E-02 --

Arsenic - 2.96E-03 - --Barium 3.71E-01 2.43E-01 -

Beryllium 1.04E-02 3.66E-03 --Cadmium 5.10E-03 5.10E-03 -- --

Calcium 124E+02 9.76E+01Chromium 5.81E-01 3.15E-01 --Cobalt 7.03E-02 7.82E-02 -- -

Copper 3.84E-01 2.49E-01 -- --Iron 3.36E+02 1.78E+02 -- --Lead -- 1.76E-02 - -

anMangese 7.19E+00 4.29E+00 -.--

Mercury 225E-04 --Nickel 1.43E-01 5.86E-02 --Potassium 3.00E+01 2.70E+01 9.47E+01 9.80E+01Selenium -- 9.87E-04 --

TABLE 2 (Continued)

CONTAMINANTS OF POTENTIAL CONCERN FOR HUMAN HEALTH RISK ASSESSMENTGROUNDWATER DATA SUMMARY -


Constituent

Blanket DepositGroundwater (mg/L)

Shallow LimestoneGroundwater (mg/L)





Inorganics and Cyanide (continued)Sodium 1.93E+02 1.12E+02 -- --Vanadium " 9.24E-01 4.93E-01 -- --

Zinc 4.67E-01 2.57E-01 -- --Cyanide 6.65E-03 5.72E-03 8.00E-03 5.63E-03

Notes:

mg/L milligrams per liter

TABLE 3

TOXICITY VALUES - SLOPE FACTORSSUMMARY TABLE OF CARCINOGENIC SLOPE FACTORS

SITE 4/7, SABANA SECA, PUERTO RICO

Constituents

Oral SlopeFactor

(mg/kg-day)-'Unit Risk

( lga-) Class

Inhalation SlopeFactor

(mg/kg-day)Unit Risk

(11e10Volatiles

Acetone NM') NM') D NM') NAP)2-Butanone NM') NM') D NMI ) NM')Benzene 0.029 a 0.00000083 A 0.029 a 0.0000083 aCarbon Disulfide NM') NA0 ) NA0) NA0) NA0)Chloroform 0.0061 a 0.00000017 a B2 0.0805 a 0.000023 aMethylene Chloride 0.0075 a 0.00000021 a B2 0.00164 a 0.00000047 aTetrachloroethene 0.052 c 0.0000015 c NA 0.002 c 0.00000058 cToluene NM') NM' ) D NAP) NAP)

SemivolatilesBenzoic Acid NM') NM') D NAP) NAP)Bis(2-ethylhexyl)phthalate

0.014 a 0.0000004 a B2 NM') NAP)

Butylbenzylphthalate NM') NAP) C NAP) NAP)Di-n-octyl phthalate NA0) NM') NM') NM') NA0)Phenol NM') NMI ) D -NAO) NA0)Nitrobenzene NM') NM') D NAP) NAP)

Pesticidesalpha-BHC 6.3 a 0.00018 a B2 NAP) NAP)beta-13HC 1.8 a 0.000053 a C. NAP) NAP)delta-13HC NM') NA0) D NM') NM')gamma-BHC (Undane) 1.3 b 0.000037 b B2 NAP) NAP)EndOsulfan I NM') NA0) Nito) NAP) NAP)

PCBsAroclor 1248* 7.7 a I 0.00022 a I B2 NAP)I NAP)

Herbicides2,4-D NA0) NMI ) NA0) NM') NM')Dichloroprop NMI ) NAG ) NAP NAP) NAP)Silvex NA0) NMI ) D NAP) NAP)

Inorganics and CyanideAluminum NA0) NMI ) NAO) NAP) NAP)Antimony NM') NMI) NM') NAP) NAP)Arsenic 1.75 a 0.00005 a A NAP) NAP)Barium NM') NA(') WO NAP) NAP)Beryllium 4.3 a 0.00012 a B2 NAP) NAP)Cadmium NM') NM') B1 NAP) NAP)

TABLE 3 (Continued)

TOXICITY VALUES - SLOPE FACTORSSUMMARY TABLE OF CARCINOGENIC SLOPE FACTORS

SITE 4/7, SABANA SECA, PUERTO RICO

Constituents

Oral SlopeFactor

(mg/kg-day)- 1Unit Risk

018/14 Class

Inhalation SlopeFactor

(mg/kg-day)Unit Risk

(118/m3)Inorganics and Cyanide (continued)

Calcium NM') NM') NM') NAP) NAP)Chromium(+3) NM') NM') NM') NAP) NAmChromium(+6) NM') NA0) A NAP) NAP)Cobalt NAM NMI ) NA0) NAP) NAP)Copper NA0) NA0) D NAP) NAP)Iron NAP) NAB ') NM') NAP) NAP)Lead NM') NM') B2 NAP) NAP)Magnesium NM') NA0 ) NM') NAP) NAP)Manganese NA0) NA0 ) D NAP) NAP)Mercury NM' ) NAP) D NAP) NAP)Nickel NM') NAB ') NA0) NAP) NAP)Potassium NA0) NA0) Niko) NAP) NAP)Selenium NM') NM') D NAP) NAP)Sodium NM') NAB ') Mu) NAP) NAP)Vanadium NAB ') NM') NM') NAP) NAP)Zinc N I ) NA0) D NAM NAP)Cyanide NM') Niko) D NAP) NAP)

Notes:

IRIS (EPA, 1994b).b - HEAST, FY 1993 (EPA, 1993b).c - EPA Region III Risk-Based Concentration Table (EPA 1994c).NA0) - Not available.NAM- Not used for this risk assessment.mg/kg-day --- milligrams per kilogram per daygg/L - micrograms per literj.tg/m3- micrograms per cubic meter* Carcinogenicity values were not available for Aroclor 1248; the values for general PCBs were used for evaluation.

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