United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R10-93/072
September 1993
£EPA Superfund
Record of Decision
Fort Lewis Logistic
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50272-101
REPORT DOCUMENTATION 11. REPORT NO.
PAGE EPA/ROD/R10-93/072
2.
3. Reclpient'e Acca_ion No.
4.
Title end Subtitle
SUPERFUND RECORD OF DECISION
Fort Lewis Logistic Center, WA
Second Remedial Action
Author(a)
5.
Report Date
09/24/93
6.
7.
8.
Performing Organization Rapt. No.
9.
Performing Organization Name and Addr-
10
ProJact Ta_klWork Unit No.
11. Contract(C) or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Name and Add.....
U.S. Environmental Protection
401 M Street, s.W.
Washington, D.C. 20460
13. Type of Raport & Parlod Coveract
Agency
800/800
14.
15. Supplementary Note-
PB94-964618
16. Abstract (Limit: 200 word.)
The Fort Lewis Logistic Center site is part of a 650-acre military storage and
maintenance facility in Pierce County, Washington. Land use in the area is mixed
residential, military, and recreational. The site overlies a surficial aquifer and a
deeper, bedrock aquifer that is used as a water supply and contains several lakes, a
creek, a marsh, and a small, forested wetland. The Fort's primary water sources,
Sequalitchew Springs and Sullivan Well, are located within a 1,800 foot-radius of the
Fort's landfill. Two sites within a common area of the Fort, Landfill 4 (LF4) and the
Solvent Refined Coal Pilot Plant (SRCPP), have been. contaminated by site operations,
which primarily consisted of equipment repair and maintenance. LF4 occupies
approximately 52 acres in the northern part of the Fort and was developed in 1951 by
placing refuse in two gravel pits. Land filling was expanded to the south and west
until 1967, when the landfill was closed and covered with gravel. Although no landfill
records exist, the waste materials likely consisted of domestic and light industrial
solid waste. In 1988, a site investigation indicated that shallow ground water around
the landfill was contaminated with chlorinated hydrocarbons, primarily TCE, and that
treated water from Sequalitchew Springs and the Sullivan Well contained several VOCs.
The SRCPP occupies approximately 25 acres between Sequalitchew Lake and Hamer Marsh and
(See Attached Page)
17. Document Analysl. a. Dncrlptora
Record of Decision - Fort Lewis Logistic Center, WA
Second Remedial Action
Contaminated Media: soil, gw
Key Contaminants: VOCs (TCE, vinyl chloride), other organics (PAHs)
b.
IdentifieralOpen-Ended Tarms
c.
COSATI Field/Group
18. Availability Statement
19. Security Clan (ThIs Report)
None
20. Security Class (This Page)
None
21. No. of Paga.
no
22. Price
(Sea ANSI-Z39.18)
See Instructions on Reverse
OPTIONAL FORM 272 (4-77)
(Formerly NTI8-35)
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EPA/ROD/R10-93/072
Fort Lewis Logistic Center, WA
Second Remedial Action
Abstract (Continued)
primarily is covered with a gravel or asphalt surface. From 1974 to 1981, the SRCPP
operated as a production/research facility designed to develop a solvent extraction
technology for deriving petroleum, hydrocarbon-like products from coal. The facility
converted coal into a low-sulfur, low-ash solid product (SRC-I) by the solvent refined
coal process. The process was later modified to distill the volatile fractions and produce
liquid fuel products (SRC-II). Incoming coal was stored in uncovered piles, as were solid
products awaiting shipment and sulfur. End products of the SRC-II process included light
oil, wash solvents, recycled solvents, and solid, as well as byproduct solid, liquid, and
gaseous waste. Liquid waste was directed to an onsite wastewater treatment plant or
disposed of offsite through a system of subsurface drain lines that were later shown to be
leaking, and solids reportedly were disposed of off site. Treated wastewater was
discharged to the wastewater lagoon, and overflow from the lagoon entered the adjacent
Harner marsh. Contaminants in the solid and liquid waste included PAHs, VOCs, SVOCs, and
oils, and surface water runoff from on-site storm sewers contained PAHs, phenols, metals,
coals, and other contaminants. In 1979, a 2,000-gallon spill of liquid fuel from the
SRCPP resulted in soil and ground water investigations. In 1980, a large volume of soil
was removed from the spill area and reportedly a ground water extraction and treatment
system was implemented to remediate the underlying aquifer. In 1982, sludge in the
wastewater lagoon was excavated as part of facility decommissioning. The spill and
decommissioning led to monitoring and investigations, conducted in 1991, which showed that
soil and ground water had been contaminated by site activities and previous waste handling
practices. A 1990 ROD addressed contaminated ground water in the surficial aquifer
beneath the entire Fort and provided for further investigation of contaminants in the soil
and deeper aquifer. This ROD addresses contaminated soil and deep, ground water at the
LF4 and the SRCPP sites. The primary contaminants of concern affecting the soil and ground
water are VOCs, including TCE and vinyl chloride; and other organics, including PAHs.
The selected remedial action for this site includes installing and operating a network of
vapor extraction wells along with an air sparging system to strip the contaminants from
both soil and ground water at the LF4; using carbon adsorption to control air emissions;
disposing of spent carbon at an offsite disposal or recycling facility; reinjecting
treated water onsite; excavating and treating soil from the former process area at the
SRCPP onsite using soil washing or thermal desorption; disposing of treated residuals at
an offsite facility, if thermal desorption is used; backfilling the excavated areas with
treated soil; allowing contaminant concentrations to naturally attenuate over a fifty-year
period; monitoring ground water; and implementing institutional controls, including land
use restrictions. The estimated present worth cost for this remedial action is
$7,117,000.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific soil cleanup goals for the SRCPP are based on MTCA Method B, and include
PAHs 1 mg/kg. Chemical-specific ground water cleanup goals for the LF4 are based on MTCA
Method Band SDWA MCLs and MCLGs, and include TCE 5 ug/l and vinyl chloride 1 ug/l.
Chemical-specific soil and ground water cleanup goals for the LF4 and the SRCPP,
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RECORD OF DECISION
for
LANDFILL 4
and the
SOL VENT REFINED COAL PILOT PLANT
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TABLE OF CONTENTS
Page
Declaration of the Record of Decision. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " 1
Decision Summary
IV.
I.
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6
n.
Highlights of Community Participation. . . . . . . . . . . . . . . . . . . . . . . . " 6
A. Community Relations During the RI/FS . . . . . . . . . . . . . . . . . . . . . .. 6
B. Community Relations to Support Selection of Remedy. . . . . . . . . . .. 9 '
III.
Landfill 4 . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. 9
A. Site Name, Location, and Description. . . . . . . . . . . . . . . . . . . . . . .. 9
B. Site History and Enforcement Activities. . . . . . . . " . . . . . . . . . . . .. 12
C. Scope and Role of Response Action Within Site Strategy. . . . . . . .. 13
D. Summary of Site Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . " 13
E. Summary of Site Risks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 25
F. Remedial Action Objectives. . . . . . . . . . . . . . . . . . . . . . . . . . .'. .. 44
G. Description of Alternatives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 45
H. Summary of Comparative Analysis of Alternatives. . . . . . . . . . . . " 47
I. The Selected Remedy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 50
J. Statutory Determinations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " 51
K. Documentation of Significant Changes. . . . . . . . . . . . . . . . . . . . . .. 54
SRCPP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 54
A. Site Name, Location, and Description. . . . . . . . . . . . . . . . . . . . . .. 54
B. Site History and Enforcement Activities. . . . . . . . . . . . . . . . . . . . .. 55
C. Scope and Role of Response Action Within Site Strategy. . . . . . . .. 57
D. Summary of Site Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . .. 58
E. Summary of Site Risks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 67
F. Remedial Action Objectives. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 87
G. Description of Alternatives. . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. 87
H. Summary of Comparative Analysis of Alternatives. . . . . . . . . . . . .. 91
1. The Selected Remedy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 95
J-. Statutory Determinations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 96
K. Documentation of Significant Changes. . . . . . . . . . . . . . . . . . . . . .. 98
Responsiveness Summary. . ; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " 99
List of Acronyms and Abbreviations. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . 101
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DECLARATION OF THE RECORD OF DECISION
SITE NAMES AND LOCATION
Landfill 4 and the Solvent Refined Coal Pilot Plant
Fort Lewis Military Reservation
Pierce County, Washington
ST A TEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial actions for two sites, Landfill 4 (LF4)
and the Solvent Refined Coal Pilot Plant (SRCPP), located on the Fort Lewis Military
Reservation, Pierce County, Washington. The selected remedial actions for each site were
chosen in accordance with the Comprehensive Environmental Response, Compensation, and
Liability Act of 1980 (CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986, and to the extent practicable, the National Oil and Hazardous
Substances Pollution Contingency Plan. Selection of each remedial action is based on the
administrative record for the sites.
All investigative activities at these sites were conducted under a Federal Facility Agreement
entered into by the U.S. Army, U.S. Environmental Protection Agency (EPA), and the
Washington State Department of Ecology (Ecology), pursuant to Section 120(e) of CERCLA.
The lead agency for this decision is the Anny. EPA approves of these decisions and, along
with Ecology has participated in the scoping of site investigations, evaluation of data, and
analysis of remedial alternatives. The State of Washington concurs with the selected
remedies.
ASSESSMENT OF THE SITES
Actual or threatened releases of hazardous substances from these sites, if not addressed by
implementing the response actions selected in this Record of Decision, may present an
imminent and substantial endangerment to public health, welfare, or the environment.
DESCRIPTION OF THE SELECTED REMEDIES
The selected remedy for LF4 includes treatment of suspected sources of groundwater
contamination, treatment of contaminated groundwater. groundwater monitoring, and
implementation of institutional controls to protect human health and the environment during.
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.
Installing an active soil vapor extraction. system (YES) in suspected groundwater
contamination source areas. Vapors from the system will be treated in compliance
with air quality regulations prior to discharge.
.
Installing an in situ groundwater sparging system to remove volatile contaminants
from groundwater. The sparging system will work in conjunction with the YES.
.
Monitoring upper aquifer groundwater to determine the effectiveness of the selected
remedy.
As part of the monitoring program, the localized area of elevated manganese along the
western borders of South and Northwest LF4 will be monitored to determine any
changes in manganese concentrations. If the monitoring indicates that manganese
concentrations are not declining, the need for remediation of the localized area will
then be reevaluated. This reevaluation may include supplemental sampling, or
additional source characterization.
.
Maintaining institutional controls restricting access to and development at the site as
long as hazardous substances remain onsite at levels that preclude unrestricted use.
The selected remedy for the SRCPP includes excavation and treatment of contaminated soils,
groundwater monitoring, and institutional controls to protect human health and the environment
during remedial action. Major components of the SRCPP selected remedy include:
.
Excavating and treating contaminated soils. Soils will be treated using either soil
washing or low temperature desorption to meet cleanup levels.
.
Monitoring upper aquifer groundwater beneath and adjacent to the site to determine
the effectiveness of the selected remedy.
.
Maintaining institutional controls restricting access to and development at the site as
long as hazardous substances remain onsite at levels that preclude unrestricted use.
STATUTORY DETERMINATIONS
The selected remedies are protective of human health and the environment, comply with
Federal and State requirements that are legally applicable or relevant and appropriate to the
remedial actions, and are cost-effective. The remedies utilize permanent solutions and
alternative treatment technologies to the maximum extent practicable, and satisfy the statutory
preference for remedies that employ treatment ~hat reduces contaminant toxicity, mobility, and
volume as a principal element.
A review will be performed not less often than every five years after initiation of the final
response actions, as long as hazardous substances remain onsite at levels that preclude
unrestricted use. .
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Signature sheet for the foregoing Fon Lewis Landfill 4 and the Solvent Refmed Coal Pilot
Plant Record of Decision between the U.S. Depanment of the Anny and the U.S.
EnviroQrnental Protection Agency, with concurrence by the Washington State Depanment of
Ecology.
Lewis D. Walker
Deputy Assistant Secretary of the Army (1, L, &E)
Environment, Safety, and Occupational Health
Date
Carmen J. Cavezza
Lieutenant General, U.S. Army
Commander, I Corps and Fort Lewis
Date
,.,
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Signature sheet for the foregoing Fon Lewis Landfill 4 and the Solvent Refined Coal Pilot
Plant Record of Decision between the U.S. Depanment of the Army and the U.S.
Environmental Protection Agency, with concurrence by the Washington State Depanment of
Ecology.
/~t1~
Gerald A. Emison
Acting Regional Administrator, Region 10
U.S. Environmental Protection Agency
? -z-~-f' .5
Date
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Signature sheet for the foregoing Fon Lewis Landfill 4 and the Solvent Refined Coal Pilot
Plant Record of Decision between the U.S. Department of the Army and the U.S.
Environmental Protection Agency, with concurrence by the Washington State Depanment of
Ecology.
Carol L. Fleskes
Manager
Toxies Cleanup Program
Washington State Deparnnent of Ecology
Date
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DECISION SUMMARY
I. INTRODUCTION
This decision summary addresses two sites, Landfill 4 (LF4) and the Solvent Refined Coal
Pilot Plant (SRCPP), both located on the U.S. Army's Fort Lewis Military Reservation (Fort)
in western Washington State. The two sites lie within a common study area, shown on
Figure 1. The relationship of the two sites is shown on Figure 2.
An installation-wide Federal Facility Agreement (FFA), Administrative Docket Nos. 1088-06-
16-120 and 1089-09-23-120, between the U.S. Army (Army), the U.S. Environmental
Protection Agency (EPA), and the Washington State Department of Ecology (Ecology)
became effective January 29, 1990. The FFA establishes a procedural framework for agency
coordination and a schedule for all Comprehensive Environmental Response, Compensation,
and Liability Act of 1980 (CERCLA or Superfund), as amended by the Superfund
Amendments and Reauthorization Act of 1986, activities conducted at Fort Lewis.
Pursuant to Executive Order 12580 (Superfund Implementation) and the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP), the Army performed a Remedial
Investigation/Feasibility Study (RIfFS) for LF4 and the SRCPP. The Remedial Investigation
(RI) (1993) characterized contamination in the air, groundwater, sediments, surface water, and
soil. The Baseline Risk Assessment (RA) (1993) evaluated potential effects of the
contamination on human health and the environment. The Feasibility Study (FS) (1993)
evaluated alternatives for remediating contamination. In accordance with section 120(e)(2)" of
CERCLA, the Army will begin the remedial action within 15 months of completion of the
Rl/FS process.
Following Section II (Highlights of Community Participation), the decision summary is
organized by site. Thus, the LF4 summary is presented first, followed by the SRCPP
summary.
II. HIGHLIGHTS OF COMMUNITY PARTICIPATION
A.
COMMUNITY RELATIONS DURING THE RIfFS
A community relations plan (CRP) was prepared in 1992 as part of the management plan for
LF4 and the SRCPP. The CRP was designed to promote public awareness of the
investigations and public involvement in the decision-making process.
Local citizens and public officials were interviewed to identify potential issues and concerns
associated with LF4 and the SRCPP. This information was used to focus the CRP to meet
the specific needs of the local communities and to guide development and implementation of
the RIIFS.
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In February 1993, a Community Information Update. newsletter was prepared and distributed,
which described the RIlFS work underway at LF4 and the SRCPP.
To promote community awareness of RIlFS activities, information repositories containing site
documents were established at the Pierce County Library (Lakewood Branch and Tillicum
Branch) and Fort Lewis (Directorate of Engineering and Housing, Environmental and Natural
Resources Division).
Also, in accordance with section 113 of CERCLA, an administrative record was established to
provide the basis for the selected remedies. The administrative record is available for public
review at the Fort Lewis Environmental and Natural Resources Division.
B.
COMMUNITY RELATIONS TO SUPPORT SELECTION OF REMEDY
In accordance with sections 117 and 113(k)(2)(B) of CERCLA, the public was given the
opportunity to participate in the remedy selection process. The proposed plan, which
summarized the alternatives evaluated and presented the preferred alternatives, was mailed to
approximately 250 interested parties in May 1993. The Army provided public notice through
a display ad in the Tacoma News Tribune and the Northwest Guardian to explain the
proposed plan, list the public comment period, and announce the public meeting.
A 30-day public comment period was held from May 31 to June 30 1993. No requests for
extensions were received during the comment period. Approximately 10 community members
attended the open house/public meeting, which was held on June 15, 1993 in the DuPont City
Hall/Community Center. Three written comments were received. Responses to these
comments are included in the Responsiveness Summary.
A fact sheet summarizing the Record of Decision (ROD), public comments, and the Army's
response will be mailed to interested parties on the mailing list after the ROD is signed.
Copies of the ROD and the Responsiveness Summary will be placed in the administrative
record and in the information repositories.
Ill. LANDFll...L 4
A.
SITE NAME, LOCATION, AND DESCRIPTION
LF4 occupies approximately 52 acres on the North Fort portion of Fort Lewis. As shown on
Figure 2, Vancouver Road bisects the landfill into two approximately equal sections. north
and south. The north section is further divided into two parts by an unimproved dirt road.
These two parts are designated Northeast and Northwest LF4. The south section of the
landfill. is designated South LF4.
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Northeast LF4 is covered with low relief grasses, shrubs, and scattered deciduous and
coniferous trees in its sou~ern portion. Unimproved din roads traverse the surface of
Northeast LF4, but vehicle traffic appears limited. Surface elevations range from
approximately 225 to 240 feet above Mean Sea Level (MSL). The central portion of
Northeast LF4 is depressed relative to the surrounding topography.
Northwest LF4 is covered with low relief grasses and shrubs. A large, post-closure,
irregularly shaped berm with. an inner depression lies just north of Vancouver Road. The
berm's sides are covered with brush and show some exposed refuse. Other than the
earthwork and a relatively small, post-closure excavation on its western boundary, Northwest
LF4 is relatively flat. Surface elevations range from 235 to 245 feet above MSL, matching
the surrounding topography.
South LF4 is covered with low relief grasses and scattered deciduous and coniferous trees.
Unimproved dirt roads also traverse this section of the landfill. South LF4 surface elevations
typically range from approximately 230 to 235 feet above MSL. Portions of the southeast and
western boundaries slope steeply downward to match relatively depressed natural topography.
Surface water bodies within the study area include the western portion of Sears Lake, the
southwestern tip of American Lake, Sequalitchew Lake, Sequalitchew Springs, Sullivan Well,
Sequalitchew Creek, Hamer Marsh, and a small forested wetland west of South LF4. These
features are shown on Figure 2.
Land uses around LF4 include residential to the east, military to the west, north, and east, and
recreational to the south adjacent to Sequalitchew Lake. No residences or offices are located
directly adjacent to the landfill. However, some military training exercises take place on or
adjacent to the landfill. General surrounding land use is indicated on Figure 3.
The Fort's primary water sources, Sequalitchew Springs and Sullivan Well, are both located
within the study area as shown on Figure 2. Water from the Springs is adequate to meet
current FOIt demand during the winter, but is frequently supplemented by Sullivan Well and
other sources during the summer due to higher demand.
Sequalitchew Springs has been the primary source of drinking water for the Fort since its
inception. Sequalitchew Springs is currently covered by a concrete-walled and roofed
structure. At its closest approach, LF4 lies approximately 1,350 feet northwest of the Springs.
Sullivan Well (also referred to as wells 12A and 12B) is a developed spring comprising two
adjacent, shallow, dug wells used to supplement Sequalitchew Springs water production
during periods Of high demand. Sullivan Well is located approximately 1,800 feet south of
the Springs.
Water supply wells 19A and .19B are also located in the study area. These deep wells are
generally not in service because they are used only as backup water supply sources.
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Current Study Area Land Use
Landfill 4/SRCPP ROD
Fort Lewis. Washington
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There are no known archeological, historical, or cultural resources located on or in the
vicinity of LF4. No threatened or endangered flora are known to occur on or adjacent to
LF4. One federally listed threatened species, the bald eagle, has been obseIVed within the
study area; however, bald eagles do not nest on or near LF4.
B.
SITE HISTORY AND ENFORCEMENT ACTIVITIES
LF4 development began in about 1951 by placing refuse in the northernmost of two gravel
pits between Vancouver Road and 41st Division Drive. Landfilling was expanded to the
south and west of the original pit, forming Northeast and Northwest LF4, until approximately
1961. Gravel mining continued in the southern pit until the late 1970s.
Landfilling extended to the area south of Vancouver Road (South LF4) in 1961, and
continued there until about 1967. All three landfill sections were closed by covering with
gravel, which was graded into a series of parallel furrows to promote surface water runoff and
check erosion.
Although there are no landfilling records, the waste materials probably consisted of domestic
and light industrial solid waste (including domestic liquids and biosolids collected by septic
tank pump trucks) and construction debris. Refuse thickness likely ranges from
approximately 9 to as much as 20 feet. A 1960 aerial photograph shows several aboveground
storage tanks, vehicles, a gravel screen plant, and other unidentified equipment south of
Northeast LF4, and several small buildings, a potential liquid waste disposal pit, and other
vehicles and equipment near the western edge of Northeast LF4. A 1966 aerial photograph
shows several small buildings and a circular pit, similar to those noted on the 1960
photograph at Northeast LF4, located on South LF4.
A 1988 investigation of LF4 by Battelle's Pacific Northwest Laboratory (PNL) indicated
shallow groundwater around th,e landfill was contaminated by several chlorinated
hydrocarbons, principally trichloroethene (TCE), at concentrations ranging from 1 to 32
micrograms per liter (pg/L). The highest TCE concentration was detected in a monitoring
well (PNL3) located between LF4 and Sequalitchew Springs.
Water quality data for Sequalitchew Springs, Sullivan Well, and wells 19A and 19B was
obtained for the years 1986 through 1989. Sequalitchew Springs is tested quanerly and
Sullivan Well, Well 19A, and Well19B yearly for volatile organic compounds (VOCs),
corrosivity, inorganic compounds, and total trihalomethanes. Several VOCs considered to be
chlorination by-products were detected in the treated water from Sequalitchew Springs and
Sullivan Well. '
Based on the FF A and the results of PNL' s 1988 sampling, an RIIFS was initiated at LF4 in
1991. The RIfFS characterized the nature and extent of contamination, assessed site risks to
human health and the environment, and evaluated remedial alternatives.
-------
c.
SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY
The selected remedy is intended to address all unacceptable risks resulting from contami-
nation at LF4. It reduces risks associated with potential exposure through treatment of likely
sources of ongoing groundwater contamination within soil and direct remediation of
contaminated groundwater. .
Institutional controls are included to prevent construction of new water supply wells and
residences on or near LF4. Long-term groundwater monitoring will verify the effectiveness
of the selected remedy. .
D.
SUMMARY OF SITE CHARACTERISTICS
1.
Geolo!!v and Hvdro!!eolo!!v
LF4 is situated on a glacial drift plain. The elevation of the plain in the vicinity of the
landfill is 200 to 250 feet above MSL. Major features of relief in the study area are several
kettles (glacial-derived depressions) which include Sequalitchew, Sears, and American Lakes.
Geologic and hydrogeologic conditions in the study area were investigated by drilling 20
borings and completing them as groundwater monitoring wells. Stratigraphic correlations
between boreholes were made and six sttatigraphically distinct deposits were identified
underlying LF4 as shown in Figure 4. The uppermost formation, the Vashon Drift, is
approximately 75 feet thick and consists of gravels, silty gravels, and sand. Beneath the
Vashon Drift is the Discovery Nonglacial Unit,which consists of sands and silty sands ranging
in thickness from approximately 30 to 70 feet. The Discovery Nonglacial Unit appears to be
depositionally absent beneath portions of northeast and northwest LF4. Beneath the
Discovery Nonglacial Unit, or the Vashon Drift where the Discovery Nonglacial Unit is
absent, is the Narrows Glacial Unit which consists primarily of lodgement till and sandy
gravel outwash, ranging in depth from approximately 5 to 80 feet Underlying the Narrows
Glacial Unit is the Kitsap Formation which ranges in thickness from approximately 10 to .+5
feet and generally occurs as a fme-grained sand and a silt with sand and peat interbeds.
Because of its fine-grained character, the Kitsap Formation is generally considered a regionJI
aquitard. Underlying the Kitsap Formation is the Flett Creek Glacial Unit, which ranges in
thickness from 70 to 85 feet and consists of a very dense, unsorted gravel with silt and sand
(lodgement till), underlain by a coarse grained sandy gravel (outwash). Beneath the Flett
Creek Glacial Unit is the Clover Park Nonglacial Unit, which was over 100 feet thick in the
deepest boring, and included sandy gravel, sand, and silt.
Two aquifers and two aquitards were defined beneath the site. The upper aquifer occurs
under unconfined (water table) conditions within the Vashon Drift, Discovery Nonglaci:.d
Unit, Narrows Glacial Unit gravel outwash, and Kitsap Formation sand throughout the :-!u,:~
area. The water table depth varies from 0 to a maximum of about 42 feet below ground
surface (bgs). It is generally 1:5 to 25 feet bgs near LF4.
-------
..
South < !u lJ
.( W 0 North
A 5 5 5
~ jj AI
(; J! u
J! J!
.5 LF4 LF4
SRC u
250 .. MW9A,B MW 12A,B
MW 1 A,B II) Northwesl Landfill 4 250
200. 200
150
.50
150
~ 100
s;
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..-.......... oj d... ..... ""'Int..
-.. - "' """""'IIy..........,........
d.pIcIod""''''IIY MIwo.ft ""'Int.
.100
.100
LF4
MW1B
Well'Unber
LEGEND
GrOlnd S~lace
Ov Vashon Drill Ok Kllsap FOfma11on --- Lllhologic Conlact
Stratlgraptk Contact 0 250 600
ad Discovery Nongtaclal UnlI Olc Flett Creek Glacial UnlI Waler Horlzonl.' Se." In F..'
Elevalion V.,Ue.' e..QQ8I.'1on 6.
4/7/92
an Narrows Glacial UnlI Ocp Clover Park Nonglacial UnIt
Screened "Ierval
£m..
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[J
o
o
E:.1
D
QJ
[Z]
Refuse
Sand & Gravel
Sand
Silly Sand/Sandy Silt
Bo1tom 01 BOfIng
fiGURE
Study Area Hydrogeolo.glc Section
Landfill4/SRCPP ROD
Fort Lewis, Washington
Silt with Peal inlellayers
Applied Geotechnology Inc.
Geolechnical Engineeling
Geology & Hydrogeology
~
4
Lodgemenl Till, Silly Gravel
Waler Bearing Zone
REVISEO
OATE
JOB NUMBER
14.340 100
ORAWN
OFF
APPROVED
Aqj
DATE
22 Jan 93
)
.
)
-------
Narrows Glacial Unit lodgement till, located within the upper aquifer near the north edge of
south LF4, effectively divides the aquifer into upper and lower parts in that area. This till
body is tenned the upper aquitard. .
The upper aquifer is separated from the underlying lower aquifer by a middle aquitard which
is a widespread, low-penneability deposit of Kitsap Fonnation silt and peat, and Flett Creek
Glacial Unit till. The middle aquitard is apparently effective in separating the two aquifers
since hydraulic heads in the lower aquifer are consistently 100 to 125 feet lower than in the
upper aquifer.
Groundwater in the lower aquifer occurs under confined conditions beneath the middle
aquitard, within the Flett Creek Glacial Unit outwash and the more permeable fractions of the
Clover Park Nonglacial Unit.
Groundwater in the upper aquifer is recharged by direct, rapid infilttation of rainfall and by
subsurface flow from American and Sequalitchew Lakes. Groundwater flow from the east
and south typically meets in the vicinity of LF4 and continues to the north/northwest RI
chemical disttibution data indicate some westward flow beneath LF4 as well. The upper
aquitard appears to act as a hydraulic dam, creating a large area of exttemely flat hydraulic
gradients between it and Sequalitchew Lake. This flat area is essentially a subsurface
extension of the lake.
Pumping at Sequalitchew Springs depresses the water table and reverses groundwater flow
directions in the area southeast of LF4. Under nonpumping conditions, groundwater flows
from beneath South LF4 to the west and north. Under pumping conditions, part of this flow
divens to the southeast toward Sequalitchew Springs. Groundwater flow, at the lowest water
elevations observed during the study period, is shown on Figure 5. .
Upper aquifer hydraulic conductivity estimates, derived from single borehole penneability
tests and grain size analyses, range from 0.28 feet per day (ft/day) to 1,420 ft/day. Estimated
horizontal flow velocities range from 1.2 feet per year (ft/yr) to 4,029 Nyr; the higher
velocities occur for westward flow between American and Sequalitchew Lakes, while the
lower velocities represent north/northwest flow from Sequalitchew Lake under South LF4.
Estimated horizontal flow velocities between Northeast LF4 and Sequalitchew Springs range
from 25.8 to 258 ft/yr, resulting in a ttavel time from Northeast LF4 to Sequalitchew Springs
of 5 to 50 years. Groundwater modeling results indicate that under maximum pumping rates,
approximately 1 percent of the water entering Sequalitchew Springs flows through the vicinity
of Northeast LF4.
Lower aquifer groundwater flow is generally from east to west across the site, ultimately
discharging to Puget Sound. Lower aquifer hydraulic conductivity estimates range from 14 to
142 ft/day. Lower aquifer groundwater velocities and ttavel times were not estimated because
as discussed below, LF4 does not appear to impact the lower aquifer.
-------
Water Table potentiometric surface;
- 2 f 0.5 - 0.5-foot contour Interval (dashed
where Inferred)
I
\
j
.....
In!erred groundwater flow direction
.......
Approximate groundwater divide
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Applied Geolechnology Inc.
GeuledHllcal E"Yllleellllg
Geology 8. Ilydrogeology
5
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Scale in Feel
Jon NI 'Mnrn
14,340.100
I,HAWN
OFF
Al'l'HnVr 0
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nrvisru
OllIE
IMII
-------
2.
Nature and Extent of Contamination
The RI evaluated potential LF4 impacts to air, groundwater, surface water, and soil. The
investigation revealed that there is no surface water or groundwater movement towards
Sequalitchew Lake. It was also determined during the investigation that soil hot spots
adjacent to LF4 are the suspected source of groundwater contamination. These soil hot spots
will be discussed in the section Groundwater below.
a.
Air
Landfill gases were evaluated by ambient air and passive gas surveys. Twenty gas probes
were installed within and around the landfill (refer to Figure 6 for gas probe locations).
Samples were collected on two separate occasions and were analyzed for atmospheric gases
(e.g., oxygen, methane, nitrogen) and VOCs. Table I summarizes the analytical results for
landfill gas samples collected during the RI.
The RI revealed that methane production at LF4 is low and expected to decrease further due
to the landfill's age. Chlorinated ethenes were not detected in ambient air samples collected
above the landfill surface.
Qualitative, passive gas survey results indicate areas of elevated tetrachloroethene (PCE) and
TCE flux rates (movement rates) both on and around LF4. The highest flux rates were
measured near monitoring well MW8, in two Northeast LF4 areas, and in South LF4 where it
borders Vancouver Road. Other areas of elevated PCE and TCE flux were located near the
center of South LF4, along the northeastern border of South LF4, and within the central
portion of Northeast LF4.
Low concentrations of vinyl chloride (VC) and dichloroethene (DCE) were detected in gas
probes completed within the landfill. VC was detected in three areas: the central portion of
South LF4 at a maximum concentration of 0.47 milligrams per cubic meter (mg/m3); the
southeastern edge of South LF4 at a maximum concentration of 2.4 mg/m3; and in the central
portion of Northeast LF4 at a maximum concentration of 4.1 mg/m3. DCE was detected at
the northern tip of Northeast LF4, and in one location on the southeastern border of South
LF4. The maximum detected DCE concentration was 0.20 mg/m3.
TCE was detected in three gas probes completed in native soil adjacent to LF4. The highest
soil gas levels of TCE were detected directly south of Northeast LF4 (concentrations of 1.6
mg/m3), coincident with an elevated TCE flux area detected by passive gas survey methods.
VC, DCE, and PCE were not detected in soil gas probes.
PCE and TCE are suspected human carcinogens. VC is a known human carcinogen, and DCE
is a noncarcino!!enic tOxicant. PCE and TCE are commonlv available de2reasing solvents and
.... ",.... -
were used historically at the Fort. DCE and VC are not available in pure form except within
the chemical industry: they are present at LF4 only as breakdown products of PCE and TCE.
-------
"
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, _.."'~-:'~;' "'~:,,,,,I L..:==:. l,' ...::::..
. ' ~ "':'.. ,~
..,",.." " : -....::,
LEGEND
GP17
.
Gas Probe number and approximate location
"
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"
"
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,.:,:. GP16
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\\, .../i .:'::::~..-"~'''''...';.'''-_._---==..'''''" -,;;:.-;:11-
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Applied Geotechnology Inc,
()culecll/lIcal EII!)I/JUBling
""ulogy /I. Ilydro!JuoIO!)Y
Jon NIIMOER
14,340.100
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Landfill 4: Gas Probes
Landfill 4/SRCPP ROD
Fort Lewis, Washington
6
DATE
9 ApI. 93
.REVISEO
-------
Table 1
Landfill 4: Compounds Detected in Landfill Gas and Soil Gas, Concentration Ranges,
and Frequency of Detection
Landfill 4/SRCPP ROD
Fort Lewis, Washington
::""!":'~~:':~t.~~~:Wi~i~:~~~~#.!.:I::"..:::::..j::.;::.::::.:.::':::g~.f~~~;.E~'1~~':~~:fait'I.::i.::.:.::i.::
l,ij~.~Y.lii.I~1
Benzene <0.06-0.17 4/26 <0.06-1.6 0/14
Carbon tetrachloride <0.06-0.40 2/26 <0.06 0/14
Chlorobenzene <0.06-0.09 1/26 <0.06 0/14
Chloroethane <0.06-0.79 2/26 <0.06 0/14
1,4-Dichlorobenzene <0.06-5.9 2126 <0.06 0/14
D ichlorodifluoromethane <0.06-8.7 23/26 <0.06-2.0 11/14
cis-1,2-Dichloroethene <0.06-0.20 4/26 <0.06 0/14
D ichlorotetrafluoroethana <0.06-7.0 24/26 <0.06-3.9 13/14
Ethylbenzene <0.06-3.7 8/26 <0.06 0/14
Hexachlorobutadiene <0.06-0.11 1/26 <0.06 0/14
Methylene chloride <0.06-0.07 1/26 <0.06-0.10 2114
1-Methyl-4-ethylbenzene <0.06-3.2 7/26 <0.06 0/14
Toluene <0.06-4.3 4/26 <0.06-0.21 2/14
1,2,4- Trichlorobenzena <0.06-0.09 4/26 <0.06 0/14
1,1, 1 -Trichloroethane <0.06 0/26 <0.06-0.11 1/14
Trichloroethane <0.06 0/26 <0.06-1.6 7/14
1,1,2 - Trichlorotrifluoroethane <0.06 0/26 <0.06-0.26 2114
1,2,4- Trimethylbenzene <0.06-3.2 8/26 <0.06-0.06 1/14
1,3,5- Trimethylbenzene <0.06-3.0 8/26 <0.06 0/14
Vinyl chloride <0.06-4.1 8/26 <0.06 0/14
m,p-Xylene <0.06-7.1 9/52 <0.06-0.10 1/14
o-Xylene <0.06-2.8 6/52 <0.06 0/14
Notes:
mg/m3 - Milligrams per cubic meter.
Frequency of Detection is figured as the number of samples with detections divided by the total number of samples taken.
A value expressed with < indicates the number falls below the Method Reporting Umit (MRl).
A sample location where a duplicate was taken counts as one sample in the Total Samples value. If the sample,
-------
PCE, TCE, DCE, and VC are broken down by the same microbial processes responsible for
landfill gas generation.
b.
Groundwater
Groundwater samples were collected from 30 upper aquifer and 7 lower aquifer monitoring
wells during March and June, 1992. Refer to Figure 7 for well locations. The two sampling
rounds were timed to approximate "wet" and "dry" season conditions. All samples were
analyzed for VOCs, semivolatile organic compounds (SVOCs), metals, polychlorinated
biphenyls, pesticides, and general groundwater quality indicator parameters such as major
anions and chemical oxygen demand. Table 2 summarizes the analytical results for
groundwater samples collected during the RI.
Several organic contaminants were detected in the lower aquifer at concentrations below their
respective drinking water standards. Evaluation of this data indicated that, since these
contaminants were not detected in the upper aquifer, they are not associated with LF4.
Therefore, the lower aquifer will not be discussed further.
TCE, DCE, and VC were detected in groundwater beneath the site. TCE was detected in the
uppermost part of the upper aquifer (upper aquifer-upper part) in 15 of 22 monitoring wells.
The highest TCE concentrations were measured in wells near the western tip of South LF4
and the southern tip of Northeast LF4. Groundwater monitoring wells LF4-1, -MW5, -
MW8A, and -PNL3 have the highest TCE concentrations (6 to 79 pg/L). DCE in the upper
aquifer-upper part was detected principally in wells adjacent to, or down gradient from, the
landfill. Maximum detected DCE concentration was 5.0 pg/L at MW8A, coincident with the
highest TCE concentrations. VC was detected only once in the upper aquifer-upper part,
directly east of the forested wetland adjacent to the western edge of South LF4 at an average
concentration of 4 pg/L. Figure 8 shows the distribution of chlorinated ethenes in the upper
aquifer-upper part. DCE and VC, but not TCE or PCE, were detected in the upper aquifer-
lower part. Both compounds were detected between the South and Northwest portions of
LF4; only VC was detected further downgradient.
As previously discussed, historical aerial photographs show two suspected liquid waste
disposal pits in Northeast and South LF4. The photographs also indicate equipment
operation, storage, and maintenance activities associated with gravel pit operations adjacent to
the southern part of Northeast LF4. Historically, PCE and TCE were widely used as
degreasing solvents; vehicle maintenance operations may have included degreasing, leading to
surface release of PCE and TCE. Passive soil gas, gas probe, and groundwater data indicate
elevated levels of chlorinated ethenes in the vicinity of the likely equipment operation and
maintenance activities and the two waste pits identified on the aerial photographs.
TCE (and/or PCE) disposed of outside the boundaries of LF4 would likely still exist as TCE
unless an anaerobic (oxygen-deficient) environment developed at the point of disposal. The
TCE would partition onto soil particles. into underlying groundwater, into infiltrating
-------
LF4-MW2A, B, C
o.
:,- '"
\.
."'.?"
C1
CJ
. LF4-4
LEGEND
Monitoring Well number and
approximate location
. (Upper part, Upper Aquifer)
o (Lower part, Upper Aquifer)
-$- (Lower Aquifer)
~
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..
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o 000
'--__1__=-.1
Scale In Feol
~ Applied Geotechnology Inc.
Geolechnical Engineering
Goology & Hydrogeology
Landfill 4: Monitoring Wells
Landfill 4/SRCPP ROD
Fort Lewis, Washington
7
..
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Jon NIIMnrn
14,340.100
I1I1AWtl
OFF
AI'f'110I/E 0
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OATE
9 Ap'. 93
n(VISED
-------
Table 2
Landfill 4: Compounds Detected in Groundwater, Concentration Ranges,
and Frequency of Detection
Landfdl 4/SRCPP ROD
Fort Lewis, Washington
Volatile OrQanic Compounds -
Upper Aquifer
Benzene
Carbon disulfide
Chloroform
cis-1,2-Dichloroethene
trans-1,2-Dichloroethene
1,1,2,2- Tetrachloroethane
Toluene
Trichloroethene
Vinyl chloride
lower Aquifer
Benzene
Chloroform
Ethylbenzene
Toluene
1,1.1 -Trichloroethane
Xylenes
Semivolatile OrQanic Compounds -
Upper Aquifer
Di-n-octylphthalate
Naphthalene
lower Aquifer
Di-n-octyiphthaJate
Pesticides - Upper Aquifer
Endosulfan sulfate
lower Aquifer
Endosulfan sulfate
Total Metals - Upper Aquifer
Antimony
Arsenic
Barium
Beryllium
Cadmium
Calcium
Chromium
Copper
. Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Potassium
Silver
Sodium
Zinc
Page 1 of 2
. . . .... ... . ...... ............
.. '.."H"H'_,,' ...... ......... .................. ....
....... ..........-, ...... '" "......, '...n .... . .
.1::lli.iir;~~~1;J;i-:lil!::II;~;'~~!nf.~::.
yg&
<0.5-1.7
<1-19
<0.2-1.8
<0.3-5
<0.2-0.7
<0.2-0.7
<0.5-1.2
<0.2-79
<1.0-7.8
<0.5-2
<0.2-1.5
<0.5-0.6
<0.5-5.8
<0.2-1.4
<0.5-4
yg&
<10-19
<10-1.35 J
<10-19
<0.10-1
<0.10-0.24
mq/l
<0.005-0.0066
<0.005-0.046
<0.010-2.5
<0.002-0.0080
<0.0002-0.0021
9.5-100
<0.01 -0.62
0.010-0.71
<0.088-510
<0.003-0.33
3.3-110
<0.010-12
<0.0002-0.001
<0.01 -0.68
<0.79-28
<0.005-0.013
<3.7-17
<0.01-1.3-
5150
2/8
6/50
24/50
11/50
1150
1/50
27/50
5150
5/8
3/8
1/8
5/8
1/8
4/8
10/50
. 2/50
5/8
5/50
2/8
1/50
20/50
43/50
4/50
33/50
50/50
23/50
26/50
SO/SO
28/50
SO/SO
47/50
7/50
23/50
SO/50
2/50
50/50
-------
Table 2
Landfill 4: Compounds Detected in Groundwater, Concentration Ranges,
and Frequency of Detection
Landfill 4/SRCPP ROD
Fort Lewis, Washington
.. . ...'''' ..
. . . ..... . .. ... ,.............".,.. ..
. Concentration .:f..eq.u~ncyof:
:.......R~ng~":...;:;:;:i:::::::::;p~tE!f~~.~F:.:
m9lh
<0.010-0.045
<0.0002 -0.0086
6.5-25
<0.01-0.15
0.010-0.049
0.16-9.3
<0.003-0.00635
3.8-13
<0.010-0.41
<0.01-0.095
1.2-3.1
4.7-10
0.031-0.12
Lower AQuifer
Barium
Cadmium
Calcium
Chromium
Copper
Iron
Lead
Magnesium
Manganese
Nickel
Potassium
Sodium
Zinc
Dissolved Metals - Upper Aquifer
Antimony
Arsenic
Barium
Cadmium
Calcium
Copper
Iron
Lead
Magnesium
Manganese
Potassium
Silver
Sodium
Zinc
Lower Aquifer
Arsenic
Barium
Calcium
Copper
Iron
Magnesium
Manganese
Nickel
Potassium
Sodium
Zinc
mQ/L
<0.005-0.0066
<0.005-0.011
<0.010-0.053
<0.0002 -0.00041
6.4 -99
<0.010-0.023
<0.025-7.7
<0.003 -0.0038
1.0 -49
<0.010-3
0.33-5.3
<0.005-0.064
3.2-18
<0.01-0.057
<0.005-0.0052
<0.010-0.011
4.7 -25
<0.010-0.019
<0.0'25-0.24
2.6-13
<0.010-0.30
<0.01-0.017
0.97 -2.7
3.8-9.4
0.012-0.048
5/8
6/8
S/8
4/S
3/8
S/8
3/S
8/8
7/8
4/8
8/8
8/8
8/8
1/50
4/50
15/50
6/50
SO/50
11/50
30/50
3/50
SO/50
36/50
SO/50
2/50
50/50
45/50
1/8
1/8
8/8
3/8
4/8
8/8
7/8
1/8
8/8
8/8
8/8
Notes:
J - Estimated value; all measured concentrations estimated below method reporting limit (MRL).
mg/L - Milligrams per liter. ug/L - Micrograms per liter.
Frequency of Detection is figured as the number of samples with detections divided by the total number of sampies taken.
A value expressed with < indicates the number falls below the MRL .
A sample location where a duplicate was taken counts as one sample in the Total Samples value.
It the sample, the duplicate. or both had a positive detection, it counts as one positive detection.
Total Samples is equal to the total number of samples in Round 1 plus Round 2. If a metal was only
detected in the dissolved fraction of a sample. the metal was considered detected as a total metal concentratlcn.
Background wells not considered include MW1A. MW18. MW2A, 4, MW28, MW2C. and MW4.
-------
LEGEND
Monitoring Well number and
approximate local/on, showing
TCE, total 1,2 -DCE. and VC
groundwater concentrations
LF4-MW8A (ltg/L) during 3/92 and 6/92
(NO: not detected)
TCE
1,2-DCE
VC
.
A Monitoring Well with no detections
LF4-MW6 of compounds listed above
,..
~
*:~~:~-~:::::::..:.:..."~.
..
0>
~
~
0 600
Scale In Feet
~"
I .
t~,,,,,,.".
"
y
A LF4-4
d?"
~"
'"
~
Applied Geotechnology Inc.
Geolechnical Engineering
Geology & Hydrogeology
Landfill 4: Chlorinated Ethene Concentrations In
Upper Aquifer-Upper Part
Landfill 4/SRCPP ROD
Fort Lewis. Washington
DATE
22 Jan 93
fiGURE
8
JOB NUMBER
14.340.100
DRAWN
SLB
DATE
APPROVED
ADc
-------
-\ '"
rainwater, and into the ambient air. Normally, TCE would not long remain in the coarse
surface soils surrounding LF4. However, if the TCE were co-disposed with oils and grease
(from degreasing operations), the less mobile oils and grease would act to retain part of the
TCE in the near-surface soils.
As a result of disposal, whether recent or historic, TCE has likely partitioned into the
unsaturated zone soil at various concentrations. This TCE-contaminated soil (also referred to
as a "hot spot") likely acts as a source of groundwater contamination.
Current impacts to groundwater beneath LF4 are likely the result of volatile contaminants in
the soil reaching groundwater. Infiltration of surface water and precipitation through the
surrounding soils appear to be a secondary mechanism for transport of contaminants to
groundwater.
Groundwater quality data for the upper aquifer indicate low levels of major metals and
inorganic compounds are being leached from LF4 into the upper aquifer. Leachate intrusion
into the upper aquifer is marked by increased specific conductance, alkalinity, dissolved major
metals including iron and manganese, dissolved arsenic, and biochemical oxygen demand.
Manganese was elevated above background along the western borders of South and Northwest
LF4. Manganese concentrations are significantly lower in wells further downgradient of LF4.
Results of the RI indicate that the elevated concentrations of manganese in groundwater are
caused by dissolution of manganese from geologic material in the presence of a localized area
of anaerobic groundwater. As the manganese contaminated groundwater moves
down gradient, the manganese appears to precipitate, as suggested. by rapidly declining
concentrations in immediately downgradient wells.
Sampling of upper aquifer groundwater monitoring wells south and east of LF4, betWeen the
landfill and Sequalitchew Springs, indicates no leachate impact
E.
SUMMARY OF SITE RISKS
The Baseline RA for LF4 considered human health and ecological risks. The risk
assessments were conducted in accordance with EPA'.s Risk Assessment Guidance for
Supelfund, Volume J: Human Health Evaluation Manual and Volume 2: Environmental
Assessment Manual, and EP A national guidance. The RA methods and results are
summarized in the following sections.
1.
Human Health Risks
The human health RA evaluated potential risks associated with exposure to chemical
contaminants from LF4. The assessment considered potential exposure to LF4 contaminants
in air and groundwater. Soil was not included in the quantitative RA because the landfill
cover precludes direct exposure to underiying contaminated soil. Sediment and surface \\.ater
-------
was also not included because Sequalitchew Lake and its sediments are not adversely affected
by LF4.
Both carcinogenic (i.e., causing the development of cancer) and noncarcinogenic hazard (i.e.,
direct toxic effects on organ systems, reproductive and developmental effects) risks were
evaluated. Risks were estimated for current and future land uses in the vicinity of LF4.
To ensure that potential health risks would not be underestimated, a conservative approach
was used as recommended in EPA's guidance documents. Reasonable conservative estimates
and assumptions were used to enhance confidence in the conclusions of the RA.
a.
Identification of Contaminants of Concern
Contaminants of concern (COCs) were selected for LF4 based on contaminant occurrence and
distribution in the environmental media and a risk-based screening approach. The COCs for
LF4 are shown in Table 3.
b.
Exposure Assessment
1.
Exposed Populations
Exposure pathways were evaluated 'for the following receptors:
Current Use:
On-site military personnel
Military residents
Recreationists
Future Use:
On-site resident
Adjacent residents .
Military residents using Sequalitchew Springs
11.
Exposure Pathways
Refer to Table 4 for the exposure pathways evaluated.
111.
Exposure Point Concentrations
Groundwater:
A verage and reasonable maximum exposure concentrations were estimated based on field
measurements. Groundwater exposure point concentrations were used to quantify the risks
due to ingestion of drinking water, dermal absorption during household use, and inhalation of
-------
Table 3
Landfill 4: Contaminants of Concern
landfiIl4/SRCPP ROD .
Fort Lewis, Washington
. ... . .. .......... . -.. .. ......... ...
.. .......... ............ .... . ...". ..........
..-....... ............ ............. .................... .... ... ......
. . . . . .. . .. ............ ...... . . . . . . . . . . . . . .. ..... .. . .
po6Ce.~#.~tic)h:::::. :::::::f.re'quencY:~f?:
:::n:::::.::tt~~~e;;.: :..:< ::: .:) Detection:': :':'
Upper Aquifer Groundwater
Volatile Orqanic Compounds
Chloroform
Trichloroethene
Vinyl chloride
Total Metals
Arsenic
Manganese
1M9LY.
<0.2-1.8
<0.2-79
<1.0 - 7.8
6/50
27/50
5/50
<0.005-0.046
<0.010-12
20/50
47/50
Landfill and Soil Gas
Volatile Oroanic Compounds
Vinyl chloride
(mq/m~
<0.06-4.1
8/26
Notes:
mg/m3 - Milligrams per cubic meter.
#JgIL - Micrograms per liter.
Page 1 of 1
03-Sep-93
-------
Table 4
Landfill 4: Exposure Scenario Matrix
Landfill 4/SRCPP ROD
Fort Lewis, Washington
. ..." ..
. ......... .... .....
. .... .... ...........
.". ..... . . ......
..)Scenarl~\1}.\.
9HS~li~.Mill~~tY
....".'.\p'ersonnei)' .
'" ....,.,",'.. .. '"",,",",',',,"',,',",,",,,,',',".",... ',. """"" ,",'
......~Ytr~ni...~p~.~.~.r~:...~#~ri~.rI~~......
...... ...',','.".".'."..',',.........."
. ..~~~ri~j'd~:....~
.. Recreationlsfs
....F~t4;~~~9~4r~.~J~ri;ti6i.
......
... .... . .... ..
", ........ """'''''' ".
...... '......' '"'''''' 'n'
:.s.2~hlitiqr2:V
::::\~t~.'M.~~'~.~~W~f~~("::. :
.. .)Res'de@f.
n""
"' 'n.". .
. .
... ..
. .
. "..
.. . ....
Scehari6)1:.
On 7- Site ...'.............
. Residents.
1~IIGi.1 j!\,~!~!iiiJ.
Air
Inhalation of Landfill Gas
Yes
No Yes Yes Yes
Yes N/A Yes No
UNC N/A UNC UNC
Yes N/A Yes Yes
No
Groundwater
Ingestion
Dermal Contact
Inhalation of Volatilized
Groundwater VOCs
Yes
No
No
No
No
No
Surface Water and Sediments
Ingestion
Dermal Contact
No
No
N/A
N/A
No
No
N/A
N/A
N/A
N/A
N/A
N/A
Notes:
N/A - Pathway Is not applicable for this receptor population.
Yes - Risk and/or hazard was quantified.
No - Risk and/or pathway was not quantified.
UNC - High degree of uncertainty associated with this pathway; see Baseline RA Report.
VOCs - Volatile organIc compounds.
Page 1 of 1
01 -Sep-93
-------
vacs during household use. Data from different groupings of groundwater wells were used
to estimate future exposures. Sequalitchew Springs data were used for CUITent scenarios.
The dissolved fraction of metals in groundwater was used to estimate exposure point
concentrations at LF4. Total metal concentrations were considered most representative of silt
conditions adjacent to the monitoring wells. Dissolved metal concentrations were considered
most representative of exposure point concentrations for the ingestion of groundwater from a
water supply well.
A verage and reasonable maximum exposure concentrations are listed in Table 5.
Landfill Gas and Ambient Air:
Exposure to VOCs in ambient air from landfill gas emissions were estimated for specific
exposure points using the SEAM diffusive model to generate landfill gas emission rates and
TSCREEN to model concentrations at exposure points downwind from emissions.
Figure 9 depicts the source areas and . locations of potential exposure points. Table 6 lists
estimated exposure point concentrations.
Chemical Intake by Exposure Pathway:
Chemical intakes for each exposure pathway were calculated based on the exposure point
concentrations and other exposure parameters such as water ingestion rates, inhalation rates,
dermal absorption rates, body weights, exposure frequencies and durations. Reasonable
maximum exposure calculations for the LF4 RA used values from the Standard Default
Factors document (OSWER Directive No. 9285.6-03).
c.
Toxicity Assessment
The toxicity assessment addresses the potential for a cac to cause adverse effects in exposed
populations and estimates the relationship between the extent of exposure and the extent of
toxic injury. Qualitative and quantitative toxicity information for COCs is acquired through
evaluation of relevant scientific literature. The most directly relevant data come from studies
in humans. Most of the useable information on the toxic effects of chemicals comes from
controlled experiments in animals. Table 7 lists the toxicity values for the COCs.
Slope factors (SFs) have been developed by EPA for estimating excess lifetime cancer risks
associated with exposure to potential carcinogens. SFs, which are expressed in units of
(mg/kg-day)"i, are multiplied by the estimated intake of a potential carcinogen, in mg/kg-day,
to provide an upper-bound estimate of the excess lifetime cancer risk associated with
exposure at that intake level. The term "upper bound" reflects the conservative estimate of
the risks calculated from the SF. Use of this approach makes underestimation of the actual
cancer risk highly unlikely. SFs are derived from the results of human epidemiological
-------
Tab lEi" 5
Landfill 4: Groundwater Exposure Point Concentrations
Landfill 4/SRCPP ROD
Fort Lewis. Washington
Sequalitchew Springs
. .
.... ....... '" ......H"....
.. .......... ..... .... .....
......... ..... ... . ............. .
...............,-.......-............
-..............-."......................
""-"""""""""''''''''''''''''
"..... ..-....................,-,......"
......................... ,.._,..,.,....
::::!'::::::M~im~ffi'''':::;:::
:::r9.()nc::e~tr~ti~n.
-------
Table 5
Landfill 4: Groundwater Exposure Point Concentrations
Landfill 4/SACPP AOO
Fort Lewis, Washington
Upper Aquifer, Excluding Monitoring Wells MVf1A. MW1 B, MW2A. MW2B, MW3A. MW3B, and PNL6
IDI:~lIl.il.1
Volatile OrQanicCompounds
Benzene
Chloroform
cis-1,2-0ichloroethene
Trichloroethene
Vinyl chloride
Semivolatile OrQanic Compounds
Oi-n-octylphthalate
(9.3:;3:0
0.13 D
...:.....'2. 1....
u28
0.95:0
1.7
1.8
5.0
79
4.5
0.31 0
0..14D
0.97
5.6
0.91 0
5;50
19
4.9 D
Pesticides
Endosulfan sulfate
\:0,076: D
0.077 D
Oissolved Metals
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Manganese
Mercury
Nickel
Silver
Zinc
D
11
53
0.41
<10
23
3.4
--........ ...."
.."...'... 0.0 .'.'
.::::::.:.3, 0:;
<0.2
990
33
61
3.0 D
10
0.13 0
5 0
7.0 0
1.6 0
670
0.1 0
::::::::::::21)':
3.2 0
22
o
o
D
o
:Ttd;f 0
10
o
Notes:
Shaded value indicates the lower of the UCL and maximum concentrations.
Mean and AME concentrations are used for exposure point concentrations for groundwater ingestion
in Landfill 4 Scenario 4.
a) Mean is calculated arithmetically using one-.half the method reporting limit (MAl) for nondetects.
b) Maximum concentration is the maximum concentration measured in downgradient Upper Aquifer wells.
o - Indicates the calculated value is below the MAL due to the number of nondetects.
RME - Reasonable maximum exposure is the lower of the UCL and maximum concentrations.
UCL - Upper confidence limit ot the mean calculated using log -normal transformation of the data.
uglL - Micrograms per liter.
Page20f4
0.33 0
0.14 D
2.1
28
0.95 0
5.5 0
0.078 0
3.2 D
12
0.14 0
5 0
7.7 D
1.8 0
3,000
0.1 0
26
3.2 D
-------
Table 5
Landfill 4: Groundwater Exposure Point Concentrations
Landfill 4/SRCPP ROD
Fort Lewis, Washington
lower Aquifer, Using Monitoring Wells MW98, MW128, MW14, and MW168
i~il~~'"I~'..JI~B~~~~~~
:,:m:':i:::.:i::::(H:~!9":::::::':':'i::::.":::'::'::.:',!::':~~~~'jj:.:.::::::j::'.i::j':H::'::;j..j:'ii:':::i:':.~~~H::!:,:"j:.:'::::::'::'::::\:::::::::.'J~~~:::":i::'ij':j:j:';,:
Volatile Or
Benzene
Chloroform
...
<.2.0::
: 1.5.
2.0
1.5
0.B1
0.39
2.2
1.9
."....
6.9 D
..'/:::13:.
21 M
13
Pesticides
Endosulfan sulfate
O.OB D
0.13
0.24
0.13
Dissolved Metals
Arsenic
Barium
Cadmium
Copper
lead
Manganese
Nickel
Zinc
2.B D
6.5 D
0.1 D
9.3 D
1.5 D
69
5 D
23
D
D
D
5.2
11
<0.2
19
<3.0
...:'\29Q
<10
32
3.5 D
B.B D
0.1 D
17
1.5 D
290
5 D
31
D
.j~:;jj~: D
\31
Notes:
Shaded value indicates the lower of the UCL and maximum concentrations.
Mean and RME concentrations are used for exposure point concentrations for groundwater ingestion
in Landfill 4 Scenario 4.
a) Mean.is calculated arithmetically using one-half the method reporting limit (MRL) for nondetects.
b) Maximum concentration is the maximum concentration measured in Lower Aquifer wells MW9B. MW12B, MW14,
and MW16B. .
D - Indicates the calculated value is below the MRL due to the number of nondetects.
M - Denotes the maximum mean value for duplicate samples of this compound.
RME - Reasonable maximum exposure is the lower of the UCL and maximum concentrations.
UCL - Upper confidence limit of the mean calculated using log-normal transformation of the data.
ug/L - Micrograms per liter.
-------
Table 5
Landfill 4: Groundwater Exposure Point Concentrations
Landfill 4/SRCPP ROD
Fort Lewis, Washington
Upper Aquifer. Near Trichloroethene 8Hot spor Using Monitoring Wells MW5. MWeA. MWeB. MW9A. LF4-1. and PNL3
1.1!!I.'1i1
Volatile Oraanic Compounds
Benzene
Chloroform
cis-1,2-Dichloroethene
Trichloroethene
Vinyl chloride
0.30 D
0.25
1.4
15
0.68 D
ounds
5 D
Pesticides
Endosulfan sulfate
0.07 D
Dissolved Metals
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Manganese
Mercury
Nickel
Silver
Zinc
2.5 D
7.9 D
-0.14 D
5 D
6.1 D
1.5 D
250
0.10 D
5 D
2.5 D
16
Notes:
:0.3Ef D
.....0:37/
16
9692
..0.87D
5.D
...
. ...." ........
0.0~9 D
0.6
1.8
..... ...... ....
::~::)(~~r~;?O":~
......:]9.
2.6
0.36 D
0.37
5.0
79
0.87 D
... ..... ...1. ~.~~?1..
1%'~.P.I.!.f.t...:.~....,.j. g
...........".
<10
5 D
0.20
0.09 D
D
2.5 D
11
0.17 D
5 D
7.4 D
, 1.5 D
1,600
0.10 D
5 D
2.5 D
30
D
D
D
D
<5
24
0.31
<10
18
<3.0
:m:ma;~Q9.:
<0.2
<10
<5
46
Shaded value indicates the lower of the UCL and maximum concentrations.
Mean and RME concentrations are used for exposure point concentrations for groundwater ingestion
in Landfill 4 Scenario 4.
a) Mean is calculated arithmetically using one-half the method reporting limit (MRL) for nondetects.
b) Maximum concentration is the maximum concentration measured in Upper Aquifer wells MW5, MW8A, MW8B,
MW9A, LF4-1. and PNL3.
D - Indicates the calculated value is below the MRL due to the number of nondetects.
RME - Reasonable maximum exposure is the lower of the UCL and maximum concentrations.
UCL - Upper confidence limit of the mean calculated using log-normal transformation of the data.
ug/l - Micrograms per liter.
-------
D
. ,~~"'\:,...{~\\~~~)j::::::-,
-----=~/ " I . L \\ . , ~ \ I I
---- .-.-/': { ,..::;.-.. ,--." 0 0 ~\...- \,..! :
~~.....-' :", ..;:/~f- ~---,: "',:. : ,.. ~ 00 ,J(".. ",,,,,'., " ,'. "
',' ,', ..
I, I. .' ,0,
/. ", .....,'
I' I, ",
.' ',I ','
- - -,.;' :}~:::i~:=====::~--:[2l .' ;.
,~.:. 12' .":
:(>~~- '\ \\
" .,
"
.,..
GP17 .
()
2~
LEGEND
/:,;,~~:,~~::=':'::\
, , , , , , \ \
~i (( "t\r\'~rt
: \ \ . . I , :
\\::"",- s:::::<. ':.>;/
- ,,-':',:::;::':
..' - "",...,0' . .
...: .0.';"::"'"'' ..
':.
~>""..:',
GP8 .......
"
:,.
~"GP14
'.::,~t
'.-
.,
."~"..
.
GP10
o
. '
, . '
, . .
" ,'"
.' '.' :".~..:,.",.)\:<::."
:i ()..
l~>~C:: ~~ ,,/' /0"/
J ,." ...., GP11 ,'/;;-
--....:;~,::>"-" '::~~:{'
,." 9 \:\
..~,
"
.,
..
I,
~,
Scale In Feel
..
.;
I:
..: :::- ":::':"..
. -
. -
. '
,','
: .
.'
. ,
, .
. .
. '
.,'
.':
:.
,:/,/<':, J;/'
I'::": ,,:,""",\
..' ~ I 10 I . ,/ \~.
..-.,:;:'~~-- ":.:.:' [8J :f::=::~""'-.:;:£: -0:::'
"
, ,
"::''.:~':.'-':: ::"
o
(p
f 'GURE
o
400
Landfill Gas Emission Source Areas
and Receptor ,Locations
',landfill 4/SRCPP ROD
Fort lewis, Washington
Applied Geotechnology Inc.
Geotechnical Engineering
Geology & Hydrogeology
~
9
;;.
SequalilcllCw I.ake
nATE
..
'"
"
','
"
REVISED
JOO NUMII£R
14,340.100
nRAWN
OFF
ArrRov£n
Ar:::L
DATE
-------
Table 6
Landfill 4: Landfill/Soil Gas Exposure Point Concentrations
Landfill 4/SRCPP ROD
Fort Lewis, Washington
Modeled Ambient Air Concentrations
iI8&~t-
Benzene a
Carbon tetrachloride a
Chloroethane b
1,4-Dichlorobenzene
Dichlorodifluoromethane b
Ethylbenzene b
Toluene b
Vinyl chloride a
2.9E-03
1.5E-03
2.2E -02
N/A
4.7E-01
7.BE-02
1.0E-01
B.4E-02
3.5E-03
1.7E-03
1.7E-02
N/A
3.7E-01
7.2E-02
B.3E -02
9.2E-02
3.1E-03
1.2E-03
3.6E-02
N/A
7.2E-01
1.1E-01
1.6E-01
B.eE202
4.0E-03
2.3E-03
4.4E-02
N/A
6.0E-01
1.3E-01
1.9E-01
1.0E-01
Notes:
*Figure 9 in text shows exposure locations.
Locations 6, 7, and 6 are used for Scenario 1.
Location 10 is used for Scenario 3.
a) Value represents an annual average as the chemical is carcinogenic through inhalation.
b) Value represents a 24-hour average. Chemical is not carcinogenic through inhalation.
N/A - Not calculated for this compound.
ug/m3 - Micrograms per cubic meter.
-------
Table 6
Landfill 4: Landfill/Soil Gas Exposure Point Concentrations
Ulndf~1 4/SRCPP ROD
Fort Lewis, Washington
Southern Gas Probes GP8, GP9, GP10, and GP11
Detected Within Landfill
Benzene
Carbon tetrachloride
Chloroethane
1,4-Dichlorobenzene
Dichlorodifluoromethane
Ethylbenzene
Toluene
Vinyl chloride
No Associated Toxici Values
cis-1,2-Dichloroethene
D ichlorotetrafluoroethane
1-Methyl-4-ethylbenzene
1,2,4- Trichlorobenzene
1,2,4- Trimethyfbenzene
1,3,5- Trimethylbenzene
m,p-Xylenes
o-X lenes
Notes:
1..II~~i,fl'11
0.057
0.03 D
0.2
1.5
3.5
0.79
0.92
0.69
':'::'g:~~D
2.7
2538
::::6~7.
121
380
62
0.17
<0.06 c
:""""iO.74d
<5.9 "
8.7
3.7
4.0
2.2
0.12
0.03 D
0.74
5.9
6.7
3.7
4.0
2.2
0.064
8.1
0.74
0.039
0.66
0.61
1.5
0.59
"'0'~;<
101
:Q,05~
70
49
1042
72
...",
0.19
29
.:,:,3.2::
0.1
(3.2
I:t~
>2]
0.15
15
3.2
0.055
3.2
2.9
7.0
2.7
Shaded value indicates the lower of the UCL and maximum concentrations.
a) Mean is calculated arithmetically using one-half the method reporting limit (MRL) for nondetects.
b) Maximum concentration is the maximum concentration measured in GP8, GP9, GP 1 0, and GP11.
c) The chemical was not deteded in these gas probes and the maximum concentration is taken as the MRL
D - Indicates the calculated value is below the MRL due to the number of nondetects.
mg/m3 - Milligrams per cubic meter.. "
RME - Reasonable maximum exposure is the lower of the UCL and maximum concentrations.
UCL - Upper confidence limit of the mean calculated using log-normal transformation of the data.
-------
Table 6
Landfill 4: Landfill/Soil Gas Exposure Point Concentrations
Landfill 4/SRCPP ROD
Fort Lewis, Washington
Off-Site Gas Probes GP16, GP17, and GP18
..... .,. "..".. ............ . ." "....',. ,'"
.... .:::; .",",".'. .::::; ... .. : : :,.",:,:,.",,:.:.".:.:.:.:.:.:.:.:.:."" .:. :::::. ..... . ".,. . :::........ ::. .. ...: . ... . . ..... "':::'::::;::;>::::~:;;':::~;~:~:~:~;::::::)):::
'!(~\li~~i'.TI.li&l~~j.fi~'
Detected in Soil Gas
Dichlorodifluoromethane
Toluene
Methylene chloride
Trichloroethene
1,1,2- Trichlorol1if1uoroethane
No Associated Toxicity Value
D ichlorotetrafluoroethane
0.82
0.06
0.042 D
0.39
0.068
3.5
:0.20
.0.075
48
0.29
HHH) 2.0
. 0.21
0.10
".. .1.1
,0.26
2.0
0.20
0.075
1.1
0.26
2.0
5.3
. 3.9
3.9
Notes:
Shaded value indicates the lower of the UCL and maximum concentrations.
a) Mean is calculated arithmetically using one-half the method reporting limit (MRL) for nondetects.
b) Maximum concentration is the maximum concentration measured in GP16, GP17, and GP18.
D - Indicates the calculated value is below the MRL due to the number of n0ndetects.
mg/m3 - Milligrams per cubic meter.
RME - Reasonable maximum exposure is the lower of the UCL and maximum concentrations.
UCL - Upper confidence limit of the mean calculated using log-normal transformation of the data.
-------
Table 6
Landfill 4: Landfill/Soil Gas Exposure Point Concentrations
Landfill 4/SRCPP ROD .
Fort Lewis, Washington
Modeled In-Home Exposure Point Concentrations
r£t~l.iltll
Benzene
Carbon tetrachloride
Chloroethane
1,4-Dichlorobenzene
Dichlorodifluoromethane
Ethylbenzene
Toluene
Vinyl chloride
Methylene chloride
Trichloroethene
1,1,2- TlChlorotrifluoroethane
4.0E-06
-------
Table 7
Land:iII 4: Toxicity Values for Contaminants of Concern
landfill 4/SRCPP ROD
Fort Lewis, Washington
Carcinogenic Effects
chemIcal
. . .;:.::::;;:....'(~~j~~*J;~~~t;: ...':....
::/0 fa I:: :{~..,h~',#H4A::::::#:.:
Volatile Organic Compounds
Chlorofomi
Trichloroethene
Vinyl chloride
~etals
Arsenic
6.1E-03 8.1E-02 I
1.1E-02 Hw 1.7E-02 Hw
1.9E+00 H 3.0E-01 H
1.75E+00 1.5E+01
Noncarcinogenic Effects
Chemical ..
...
. . .. . . . . . . . .. .
. . . . . . . . . . . .' ... . . . . . . . .
i~h~1~Hgri::::S:::G4UFMF:;Cl / UF<.MF
... .. ...
.: :":::'::<':::-:::,;::::":"))~~ h fri ~ Ie \~~j~~~:~\::::::::::.:.:.'; :.:::.:
::J=t~ferehce ()~$~.mf()r\
.....
~etals
Arsenic
3E-04
N/A
Manganese - diet
- water
1E-01
3.3E-02
I
C
1.1E-04
N/A
Notes:
S - Source of Information:
I - IRIS (downloaded July 1992)
H - HEAST (1992)
Hw - HEAST (1991) - withdrawn value.
C - Based on USEPA Region 10 memo.
CL - Confidence level in RIO.
. ..... ..... .
::::::Y(~'~~~~f .
::..;:::;::~~i~ ~r.~.~:; .'
.:;Gf.a~slflc~Hon
. .
. .
.. .....
Type of d~n~~~j:-r4iti~t.s.it~:::.:::.:i" ."
. ':'.:jQ~#i~ti9W::';;::::::':':::
82
82
A
Kidney and Liver
liver
liver and lung
A
Skin and lung
....
... .m':..!'!~~~J~iid~~~~~ridUri~e~~i~W
.. . . .
....,: .... :". I nha laUo ri:..:..:.::'
..
':':':';':':':';':',.:.
Med. 3
Med. 1 Med. 300
-- --
Liver
lung
liver
Respiratory system
3
Dermal and vasculature
effects
CNS and respiratory effects
CNS effects
CNS - Central Nervous System.
mg/kg-day - Milligrams per kilogram body weight per day.
MF - Modifying factor.
N/A - Factor or dose not available.
RID - Reference dose.
UF - Uncertainty factor.
-------
studies or chronic animal bioassays to which mathematical extrapolation from high doses to
low dose has been applied (e.g., to account for the use of animal data:.to predict effects on
humans). .
Reference doses (RIDs) have been developed by EPA for indicating the potential for adverse
health effects from exposure to chemicals exhibiting noncarcinogenic effects. RIDs, which
are expressed in units of mg/kg-day, are estimates of lifetime daily exposure levels for
humans, including sensitive individuals which are likely to be without risk of adverse effect.
Estimated intakes of cacs from environmental media (e.g., the amount of a cac ingested
from contaminated drinking water) can be compared to the RID. RIDs are derived from
human epidemiological studies or animal studies to which uncertainty. factors have been
applied (e.g., to account for the use of animal data to predict effects on humans).
d.
Risk Characterization
The risk characterization integrates the information developed in the toxicity assessment and
exposure assessment to characterize the carcinogenic and noncarcinogenic risks associated
with contaminant concentrations detected at LF4. The acceptable risk range for carcinogens
is one additional chance in ten thousand (I x 10-4) to one chance in one million (I x 10-6)
according to the NCP. Under the Washington State Model Toxics Control Act (MTCA), the
maximum acceptable overall site risk from carcinogens is one chance in one hundred
thousand (l x 10-5) and one chance in one million for any single contaminant (1 x 10-6).
For noncarcinogens, acceptable levels are generally those to which the human population may
be exposed during a 30 year period without adverse health effects. Noncarcinogenic risks are
estimated by calculating a Hazard Index (HI). According to both Federal and State hazardous
waste laws, an acceptable risk level for noncarcinogens is a HI value less than one.
Table 8 provides a summary of estimated health risks for each receptor and pathway.
e.
Uncertaintv
Carcinogenic and noncarcinogenic health risks were estimated in the RA for LF4 using
standard assumptions; therefore, the RA results presented in Table 8 contain an inherent
amount of uncertainty. The extent to which health risks can be characterized is primarily
dependent upon the accuracy with which a chemical's toxicity can be estimated, and the
accuracy of the exposure estimates.
Examples of uncertainty in the exposure and RA methodology used in this RA are as follows:
The exposure scenarios assume chronic exposure to contaminant levels that do
not change with time. In reality, contaminant levels often change with time in
response to source loading or depletion and physicaVchemicallbiological forces
such as chemical or biochemical degradation.
-------
Table 8
Landfill 4: Summary of Estimated Health Risks
Landfill 4/SRCPP ROD
Fort Lewis, Washington
. 'n. . .....
... .....................
'''''''''''....."....... ......
""""'.-.....--.' ...... ....
""""""*' ',''''''''''..',''''
t/\ ., ~t:!r:age::,::"
:::::::::ExP~~~!::
:::):::::::?Ch~ohi6H~~~h(!h~'~:!':::::'::::::::'
:::!!!!:!I!::~W9.J~~::!!i!!:I:!!!j
Scenario 1:
Current On-site Military Personnel
Inhalation - ambient air VOCs
Ingestion - groundwater
Total Scenario: *
3 x 10-8 5 x 10-9 1.3E-04 4.3E-05
7 x 10-8 N/C 9.8E-04 N/C
1 x 10-7 5 x 10-9 1.1 E -03 4.3E-05
Scenario 1 A:
Current North Post Military Personnel
Inhalation - ambient air VOCs
4 x 10-7
2 x 10-7
1.8E-03
1.4E-03
Total Scenario: *
4 X 10-7
2 X 10-7
1 .BE -03
1.4E-03
Scenario 2:
Current Military Residents
Ingestion - groundwater
Inhalation - VOCs via showering
- VOCs via household use
Total Scenario: *
1 x 10-7 N/C 1.4E-03 N/C
1 x 10-7 N/C N/C N/C
2 x 10-7 N/C N/C N/C
3 x 10-7 N/C 1.4E-04 N/C
Scenario 3:
Current Recreationists
Ingestion - surface water
Ingestion - sediments
Inhalation - ambient air VOCs
Child
Adult
Total Scenario (Adults): *
N/C N/C N/C N/C
N/C N/C N/C N/C
9 x 10-9 N/C B.9E-05 N/C
1 x 10-9 N/C 7 .2E -06 N/C
1 x 10-9 N/C 7 .2E -06 N/C
-------
Table 8
Landfill 4: Summary of Estimated Health Risks
Landfill 4/SRCPP ROD
Fort Lewis, Washington
. ". .... ....... .,. . .. .......... .",n.. .... .. ....... ... ....... "'" ".............-.. .
~b'=::p~tih4~&1ri~~(:.~i~k:::.::.::::::::::::::lc:~~onig:)':{~*~t~:.~.~d~*.::::::::::::::::
. . . . . .. ..... ........ .... .. . . . . . . . . . . .. ....... . .. . . . . . .. .. ... . . . .
.... """""'...."""""" -,............,-,...,...........
.'.'.','.",',".",',',",'.','.',",',',',',',',".".'.',',',".'.',', ,",",",",',',',',",',',",",".'.'''.".',',',',',',",",'.".".:.'.',
\:\::\\\::\::::\W)//::/::: /::\:Averiigi:(\?
::::::::::::::f:?f.tMg::::::I::{::::::::::rEXp~~y~!.:::::j !:IIII::I!!I!~i~~i~I!IIIIIII:!11
Scenario 4:
Future On-site Residents
Inhalation - indoor air
Ingestion - groundwater
Upper Aquifer
Lower Aquifer
8Hot Spot"
Inhalation
- VOCs via showering
Upper Aquifer
Lower Aquifer
8Hot Spot"
- VOCs via household use
Upper Aquifer
Lower Aquifer
-Hot Spot"
Total Scenario (Upper Aquifer): .
Total Scenario (Lower Aquifer): .
Total Scenario (8Hot Spotj: *
5 X 10-6 4 X 10-7 3.7E-03 1.0E-03
9 x 10-5 1 x 10-5 2.6E+00 4.2E-01
7 x 10-5 1 x 10-5 4.5E-01 1.1E-01
8 x 10-5 1 x 10-5 1.5E+00 2.1E-01
3 x 1 0 -6 1 X 10-7 N/A N/A
7 x 10-7 1 X 10-8 N/A N/A.
5 x 10-6 9 x 10-8 N/A N/A
2 x 10-5 3 x 10-6 N/A N/A
8 x 10-6 6 x 10-7 N/A N/A
3 x 10-5 3 X 10-6 N/A N/A
1 x 10-4 2 X 10-5 2.6E+00 4.2E-01
ex 10-5 1 X 10-5 4.5E-01 1.1E-01
1 x 10-4 1 X 10-5 1.5E+00 2.1 E-01
Scenario 5:
Future Adiacent Residents
Inhalation - indoor air
Ingestion - groundwater
Inhalation - VOCs via showering
- VOCs via household use
Total Scenario:
4 X 10-8 3 X 10-9 6.4E-04 2.0E -04
2 x 10-4 2 x 10-5 7.1E-01 2.5E-01
8 x 10-5 2 X 10-6 N/A N/A
1 x 10-4 9 x 10-6 N/A N/A
3 x 10-4 3 x 10-5 7.1 E-01 2.5E-01
Notes:
*Total scenario estimates calculated by summing exposure pathways and excluding inhalation of VOCs via
showering (Scenarios 2,4, and 5). There are no differences in total scenario risk estimates using either
exposure pathway for inhalation of groundwater VOCs, with four exceptions: risk estimates differ by
1 x 10-5 for Scenario 4 rHot Spotj RME conditions, Scenario 4 (Ufper Aquifer) average conditions,
and Scenario 5 average conditions; risk estimates differ by 1 x 10- for Scenario 2 RME conditions.
Scenario 6: Future Military Residents was not quantified.
RME - Reasonable Maximum Exposure.
VOCs - Volatile organic compounds.
N/C - Risk estimates or hazard indices were not calculated for this pathway.
N/A - Risk estimates or hazard indices were not applicable for this pathway.
-------
The RA evaluated a hypothetical future residential land use scenario. Given
- that Fon Lewis is currently an active military installation and will remain an
active installation for the foreseeable future, this scenario is very conservative.
The sampling locations selected for the RI were biased such that potential areas
of elevated concentrations would not be overlooked. Thus, risk estimates are
conservative.
The RA included arsenic as a cac for groundwater, without correction for
background risk due to arsenic in groundwater. Arsenic was detected in only
two wells and at concentrations very close to estimated background.
The RA included chloroform as a cac for groundwater. without correction for
its possible presence as a drinking water system chlorination by-product.
In addition to these sources of uncertainty, the chemical analytical data base has limitations in
such areas as sample locations and sample representativeness. These uncertainties are present
in every baseline RA.
2.
Ecoloeical Risk Assessment
An ecological RA was conducted to evaluate the potential adverse impactS to plants and
animals resulting from exposure to contamination associated with LF4. The results of the
ecological RA were intended to suppon management decisions on whether remedial action is
required for environmental protection.
The approach used in the RA is consistent with EPA guidance for evaluating ecological risk.
The basic steps were identification of COCs, assessment of potential exposure pathways. and
characterization of threats to exposed biota.
a.
Exposure Assessment
1.
Exposed Populations
Potential receptors were identified as those plant and animal species likely to be exposed to
chemicals in the landfill and the forested wetland west of the landfill. Considering the
relatively small amount of wildlife habitat on the landfIll, potential receptor populations Jre
probably relatively small.
No threatened or endangered plant species are known to exist in the LF4 study area. \t1
threatened or endangered animal species are known to nest within the LF4 study area: thl'
bald eagle (threatened) and peregrine falcon (endangered) have been observed flying (1\ nth,'
area. No critical habitats were identified within the study area.
-------
11.
Exposure Pathways
The exposure assessment identified potential exposure pathways from the chemical source to
the affected media, exposure points, and potential receptors. Potential exposure pathways
include the air pathway for VOCs generated within LF4 and the soil pathway for the forested
wetland. Groundwater was considered an unlikely pathway because the water table is
normally fifteen to twenty feet bgs. Consequently, ecological receptors are not expected to
come into direct contact with it
Landfill gas emissions were considered an unlikely source of ecological risk because of the
amount of dilution of the gas on mixing with air.
b.
Risk Characterization
Biota inhabiting the landfill surface and those animals burrowing into landfill soils would
likely not be at risk from inhalation-induced toxicity. ContaminantS in landfill gas were
measured at concentrations at least two orders of magnitude below levels that typically cause
acute toxicity in laboratory animals.
Biota occupying the forested wetland may be exposed to low concentrations of metals and
benzo[b]fluoranthene due to seasonal contact with groundwater which has discharged to
ground surface. These contaminantS could adhere to soil in the wetland and be present in
surface waters during very high groundwater levels. As groundwater recedes during dry
periods, wildlife could be exposed to these contaminantS through ingestion and dermal contact
routes. Exposure could only occur in the unlikely event groundwater were to discharge to the
adjacent forested wetland.
c.
UncertaintY
Assumptions that tend to overestimate potential exposure include the following:
Wildlife species are continuously exposed to maximum contaminant
concentrations.
Contaminants are 100 percent bioavailable.
Lack of analytical data for soil or surface water in the wetland habitat.
F.
REMEDIAL ACTION OBJECTIVES
Remedial action is required at LF4 for TCE and VC to protect human health and the environ-
ment under potential future land use conditions. Action is required because:
~
Upper aquifer groundwater beneath the site is contaminated with TCE and VC at
levels exceeding State and Federal maximum contaminant levels (MCLs);
-------
.
The excess cancer risk associated with reasonable maximum groundwater exposure for
potential future residential populations exceeds both Federal and State allowable risk
thresholds.
Arsenic is not included because it was detected in only two wells and at concentrations that
are below regulatory cleanup levels. Chloroform is not included because it is thought to be
present as a drinking water chlorination by-product which has entered the aquifer through
surface uses such as irrigation and vehicle washing. Manganese is not included because it is
expected that the localized area of elevated concentration will rapidly decline due to
implementation of the final remedy, as described in The Selected Remedv section.
Upper aquifer groundwater is the primary medium requiring action. To reduce ongoing
groundwater contamination, unsaturated soil in historical disposal and/or degreasing activity
areas also requires action. Remedial action objectives (RAOs) were formulated in accordance
with CERCLA for each of these media. RAOs are formulated to protect human health and
the environment from potential threats associated with site contaminants. RAGs for upper
aquifer groundwater include:
.
Prevent exposure to contaminated groundwater;
.
Restore contaminated groundwater to its beneficial use, which is drinking water;
.
Minimize movement of contaminants from soil to groundwater; and
.
Prevent exposure to landfill contents.
Upper aquifer groundwater cleanup levels have been established to meet regulatory
requirements. MTCA Method B was used to determine the cleanup level for VC at I /lg!L,
which is the practical quantitation limit (PQL) for the contaminant. The Federal MCL was
used to detennine the cleanup level for TCE at 5 pg/L.
G.
DESCRIPTION OF ALTERNATIVES
The FS developed eight remedial alternatives to reduce site risks to human health and the
environment. These eight alternatives were later consolidated into four by combining
alternatives employing similar technologies.
Alternatives and the detailed analysis are discussed below.
Alternative 1: No Action
The no action alternative is presented as a baseline comparison for other alternatives. Under
this alternative, no action would be taken to reduce contamination at LF4. A monitoring
-------
program would be implemented to monitor groundwater contamination. It is estimated that
contaminant concentrations would decrease to acceptable risk levels due to natural processes
in 30 years. Present worth costs are estimates at $48,000 given a 30-year time frame.
Alternative 2: Institutional Controls
With this alternative, groundwater monitoring would continue and institutional controls would
be implemented. Institutional controls may include access restrictions or further land use
restrictions, in addition to existing Fort Lewis groundwater well installation restrictions. It is
estimated that contaminant concentrations would decrease to acceptable risk levels due to
natural processes in 30 years. A five year review and evaluation of the data gathered during
the monitoring program would also be requiTed. Present worth costs are estimated at $54,000.
Alternative 3: Soil Treatment by Vapor Extraction and Groundwater Treatment by Sparging
This alternative includes groundwater monitoring, institutional controls, and vapor extraction
and sparging systems that would operate for approximately three years. A network of vapor
extraction wells and a vacuum pump would be installed to extract organic contaminants from
the soil. Air would be pulled through the soil subsurface and the contaminated vapor
withdrawn under vat.::uum through screened extraction wells. The vapor extraction system
(VES) would operate along with a sparging system. Sparging is the process of forcing air
through perforated pipes installed in the groundwater. Contaminants would be stripped from.
the groundwater and subsequently collected by the YES. Contaminated vapors would be
treated by a carbon filter to comply with State air quality emission standards. Spent carbon
would be disposed of at an EP A-approved off-site disposal or recycling facility. Actively
treating the soil hot spots to remove the source of contaminants to groundwater should reduce
the time frame required to achieve Cleanup standards from 30 to 15 years.. Present worth
costs are estimated at $2,260,000.
Alternative 4: Single Barrier Cap and Groundwater Treatment
This alternative includes groundwater monitoring and institutional controls, a single barrier
cap, and groundwater extraction and treatment. The design, construction, and maintenance of
the cap would meet State and Federal requirements for solid waste landfills. Emissions from
a passive gas management system would be treated as necessary to ensure compliance with
State air quality emission standards. Seven extraction wells would be installed and the
extracted groundwater would be treated using a carbon filter unit. Spent carbon would be
disposed at an off-site EPA-approved disposal or recycling facility. Treated water would be
monitored and discharged either to Sequalitchew Lake or groundwater recharge trenches,
dependent on cost and implementability. Primary drinking water standards should be
achieved in 10 to 15 years. Present worth costs are estimated at $14,288.000.
-------
H.
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
In this section, each alternative is compared against each other using the evaluation criteria
presented below. This process allows for a full comparative analysis of each alternative. The
nine criteria are categorized into three groups.
.
.
.
1.
Threshold Criteria
1.
2.
Overall protection of human health and the environment
Compliance with applicable or relevant and appropriate requirements (ARARs)
Primary Balancing Criteria
3.
4.
5.
6.
7.
Long-term effectiveness and permanence
Reduction of toxicity, mobility, or volume through treatment
Short-term effectiveness
lmplementability
Cost
Modifying Criteria
8.
9.
State acceptance
Community acceptance
Threshold Criteria
The remedial alternatives were first evaluated in relation to the threshold criteria. The
threshold criteria must be met by each alternative in order to be selected.
1.
Overall Protection of Human Health and the Environment
This criterion addresses whether each alternative provides adequate protection of human
health and the environment and describes how risks posed through each pathway are
eliminated, reduced, or controlled through ueatment, engineering controls, or institutional
controls.
Alternatives I and 2 would not provide protection from potential contaminants nor prevent
contaminant migration. Thus, Alternatives 1 and 2 are not protective of human health or the
environment.
Alternatives 3 and 4 provide similar levels of protection. Both employ institutional controls
to minimize risks during remediation. Alternative 4 may slightly reduce the time required to
meet cleanup levels. Alternative 3 would address ongoing contamination by remediating
suspected VOC source areas. Alternative 3 provides the greatest degree of flexibility in term~
-------
of allowing adjustment and tailoring of remedial technologies based on site-specific
performance.
2.
Compliance with ARARs
This criterion addresses whether or not an alternative will meet all ARARs or provide
justification for invoking a waiver for one or more ARARs.
Alternatives I and 2 may attain Federal and State groundwater cleanup levels through natural
processes (Le., dispersion, dilution, and degradation). However, in the interim, groundwater
contaminant levels would continue to exceed cleanup standards and to pose a threat to nearby
Sequalitchew Springs.
Alternatives 3 and 4 will achieve compliance with ARARs and would not require waivers.
2.
Primary Balancin2 Criteria
Once an alternative satisfies the threshold criteria, it is evaluated against five primary
balancing criteria.
Alternatives I and 2 do not satisfy the threshold criteria since they do not provide adequate
protection of human health and the environment nor comply with Federal and State
environmental standards within a reasonable time frame. Because these alternatives do not
satisfy threshold criteria, they are not considered funher in this analysis as an option for site
remediation.
3.
Long-Term Effectiveness and Permanence
This criterion refers to the expected residual risk and the ability of an alternative to maintain
reliable protection over time once cleanup goals have been met.
Alternatives 3 and 4 include a long-term monitoring program to ensure effectiveness, and
each would require enforcement of existing institutional controls, and routine inspection and
maintenance of the treatment systems. Alternative 4 would also require routine inspection
and maintenance of the landfill cover.
4.
Reduction in Toxicity, Mobility, and Volume through Treatment
This criterion describes the expected perfonnance of the treatment technologies employed hy
an alternative.
Alternative 3 would reduce the toxicity. mobility, and volume of soil and groundwater
contaminants through treatment. It employs a VES to remove contaminants from soil ;J1i,j
-------
spargingto remove contaminants from groundwater. It specifically addresses suspected
contaminant source areas.
Alternative 4 would reduce the toxicity, mobility, and volume of groundwater contaminants
through treatment but would not actively treat the suspected source of groundwater
contamination in the soil. It would employ groundwater extraction and treatment to remediate .
groundwater contaminants.
5.
Short-Term Effectiveness
This criterion pertains to the speed with which the alternative achieves protection as well as
the alternative's potential to create adverse impacts on human health and the environment
during construction and operation.
None of the alternatives would likely pose risks to human health and the environment during
construction and operation. Workers and nearby communities would be protected during site
activities by engineering and safety controls. Alternative 4 could achieve protection in the
shonest time frame (estimated 10 to 15 years); however; some uncenainty existS regarding the
effectiveness of groundwater extraction and treatment in remediating low levels of
contamination. Alternative 3 would achieve protection in approximately 15 years.
6.
Implementability
This criterion refers to the technical and administrative feasibility of implementing an
alternative, including reliability of the remedial technologies and the availability of necessary
equipment and personnel.
Alternative 3 could be implemented using existing technologies and readily available services
and materials. It would require installation of test wells and performance studies to fully
develop treatment effectiveness, and would require off-site waste disposal or recycling.
Alternative 4 could also be implemented using existing groundwater extraction treatment
technologies and readily available services and materials. It would also require off-site waste
disposal or recycling.
7.
Cost
This criterion pertains to the cost of implementing an alternative. Both capital and operations
and maintenance costs are considered.
Alternative 3, which includes groundwater monitoring for 20 years and construction and
operation of a YES and sparging system for 2 to 3 years, is estimated to cost $2,260,000.
-------
Alternative 4, which includes groundwater monitoring for 15 years and installation of a single
barrier cap and groundwater extraction and treatment system, is estimated to cost
$14,288,000. .
3.
Modifvinf! Criteria
Modifying criteria are used in the fInal evaluation of remedial alternatives.
8.
State Acceptance
This criteria refers to whether the State agrees with the selected remedial alternative.
The State concurs with the fInal remedial alternative described in this ROD. It has been
involved throughout the process and its comments have been considered and incorporated
throughout. .
9.
Community Acceptance
This criteria refers to the public support of a given remedial alternative.
Comments received during the public meeting and public comment period were considered
during selection of the fInal remedial alternative. Community response to the remedial
alternatives is presented in the Responsiveness Summary, which addresses comments received
during the public comment period.
I.
THE SELECTED REMEDY
Alternative 3 is the selected remedy. Based on the fIeld investigation, the potential source of
groundwater contamination is believed to be the soil hot spots adjacent to the landfill. This
alternative is protective of human health and the environment and complies with State and
Federal environmental standards. In addition, Alternative 3 is more cost-effective than
Alternative 4, while also affording less uncertainty regarding the effectiveness of the
treatment technologies.
1.
Maior Components Of The Selected Remedy
The selected remedy includes treatment of suspected sources of groundwater contamination,
treatment of contaminated groundwater, groundwater monitoring, and implementation of
institutional controls to protect human health and the environment during remedial action.
Major components of the LF4 selected remedy include:
.
Installing an active soil YES in suspected groundwater contamination source areas.
Vapors from the system will be treated in compliance with air quality regulations prior
to discharge.
-------
.
Installing an in situ groundwater sparging system to remove volatile contaminants
from groundwater. The sparging system will work in conjunction with the YES.
.
Monitoring upper aquifer groundwater to detennine the effectiv~ness of the selected
remedy.
As part of the monitoring program, the localized area of elevated manganese along the
western borders of South and. Nonhwest LF4 will be monitored to detennine any
changes in manganese concentrations. If the monitoring indicates that manganese
concentrations are not declining, the need for remediation of the localized area will
then be reevaluated. This reevaluation may include supplemental sampling, or
additional source characterization.
.
Maintaining institutional controls restricting access to and development at the site as
long as hazardous substances remain onsite at levels that preclude unrestricted use.
The goal of this remedial action is to restore groundwater to its beneficial use, which is, at
this site, a potential drinking water aquifer. Based on information obtained during the RI and
on a careful analysis of all remedial alternatives, the Army, EPA, and Ecology believe that
the selected remedy should be able to achieve this goaL The ability to achieve cleanup goals
cannot be detennined until the YES and groundwater sparging system have been installed,
modified as necessary, and contaminant response monitored for approximately 3 years, during
which time the system's performance will be carefully monitored on a regular basis and
adjusted as warranted by the perfonnance data collected during operation. The specific
components of the compliance monitoring program, including points of compliance, will be
developed by the Army, EPA, and Ecology during remedial design.
In the event the selected remedy does not approach the remediation goals within three years
(based on periodic groundwater sampling data), the need for additional groundwater
monitoring, groundwater extraction, capping, or excavation will be reevaluated at that time,
consistent with all regulatory requirements appropriate for the alternate remedy that is
selected.
Remediation Goals
2.
Groundwater cleanup levels have been established to meet State and Federal ARARs which
will result in a cumulative risk not to exceed 1 x 10-5. MTCA Method B was used to
determine the cleanup level for YC at I Ilg/L, which is the PQL for the contaminant. The
Federal MCL was used to determine the cleanup level for TCE at 5 J1g/L.
J.
STATUTORY DETERMINATIONS
Under CERCLA Section 121, selected remedies must be protective of human health and the
environment, comply with or provide basis for waiver of ARARs, be cost effective, and
-------
utilize permanent solutions and alternative treattnent technologies or re.~ource recovery
technologies to the maximum extent practical. CERCLA also stipulates a preference for those
remedies which, as a principal clement, significantly and permanently reduce the toxicity,
mobility, and volume. of hazardous wastes.
1.
Protection or Human Health and the Environment
The selected remedy protects human health and the environment through vapor extraction and
groundwater sparging of VOC-contaminated soil and groundwater, institutional controls. and
groundwater monitoring to en~nre remedy effectiveness- -
Residual risk at the cleanup levels is 5 x lO-s, and the residual hazard quotient is below l.
Re~idual risk exceeds the MTCA goal of 1 x lO.5 because the PQL has a risk associated with
it of 5 x 10-5, but i~ within the CERCLA acceptable range of 1 x 10-6 to 1 X 10-4.
2.
Attainment of ARARs
The ~elected remedy of vapor extraction and groundwater sparging will comply with all
ARARs of State and Federal regulations-
Action-Specific
Resoun.:e Conservation and Recovery Act (40 CFR 262). Establishes standards ior
generators of hazardous wastes for the treating. stOrage, and shipping of wastes.
Applicable to the storage. packaging, labeling, and manifesting .of the spent granulated
activated carbon off-site for treatment.
Hazardous Matcrials Transponation Act (49 use 1801-1813 and 49 CFR Pans 171
and 172). Applicable for transportation of potentially hazardous materials, including
samples and wastes.
Dangerous Waste Regulations (Chapter 173-303 WAC). Applicable for onsite
treatment. storGge. or disposal of dangerous wa~te or hazardous waste generated during
the remedial action.
Minimum Standards for Construction and Maintenance of Wells (Chapter 173-160
WAC, as modified by Engrossed Substitute Hou~e Bill I ~06). Relevant and
appropriate regulations for the location, design. construction, and abandonment of
water supply anu rcsour~c prulC4,;tion wdb.
-------
Chemical.Specific
Safe Drinking Water ACt (40 USC 300 and 40 CFR 141). MCLs for public drinking
water supplies are relevant and appropriate for setting groundwater cleanup levels.
. .
MTCA (Chapter 173.340 WAC). Method B risk. based cleanup levels are applicable
for establishing groundwater cleanup levels.
Resour~ Conservation and Recovery Act. Subtitle C (40 CFR 261). Applicable in
idenrifying if the spent activated carbon from the carbon adsorption unit is considered
a hazardous waste for purposes of transporting them off-site for treatment.
Ambient concentrations of toxic air contaminants in the puget Sound region are
regulated by the Puget Sound Air Pollution Control Agency (PSAPCA) pursuant to the
State of Washington Clean Air A~t (Chapter 70.94 RCW) and Implementation of
Regulations for Air Contaminant -Sources (Chapter 173-403 WAC).
The Best Available Control Te(;hnology (BACT) will be required for sources of toxic
air contaminants to minimize. emissions. The ambient impact of emi!;sions of toxic air
contaminants from new sources will be evaluated against Acceptable Source Impact
Levels (ASILs) adopted by PSAPCA. Toxic air contaminants are those air
contaminants listed in Appendix A of PSAPCA Regulation ill or listed in Subpart D.
40 CFR 372. The ASlL for TCE is 0.8 micrograms per cubic meter (/lg/m)) and the
ASlL for VC is 0.023 pg/m3.
Location.Specific
No location-specific ARARs.
Other Criteria, Advisori~, or Guidance to be Considered Materials
EPA OSWER Directive 9834.11. Revised~ures for-fjanning and Imvlementing
Offsite Response Actions. November 13. 1987. This directive provides procedures for
offsite disposal of CERCLA wastes.
3.
Cost Effectiveness
The selected remedy (Alternative 3) is cost-effective beCause it has been determined to
provide overall effc<..:ti",'cness proportionate to its cost and duration for remedi<\t1on nf the
contaminated groundwater.
-------
Utilization of Permanent Solutions and Alternative Treatment TechnolO2ies to the
Maximum Extent Practicable
4.
The Army, EPA, and Ecology have determined the selected remedy represents the maximum
extent to which permanent solutions and treatment technologies can be used in a cost-
effective manner for the LF4 site. The principal threats associated with the site are
pennanently reduced through treatment without transferring the risks to another media. The
selected remedy provides the best balance of long-term effectiveness and permanence.,
reduction in toxicity, mobility, and volume through treatment, shon-tenn effectiveness,
implementability, and cost
5.
Preference for Treatment as a Principal Element
The selected remedy satisfies the statutory preference for treatment as principal element by
employing YES and sparging for treatment of suspected source areas and contaminated
groundwater, respectively.
K.
DOCUMENT A TION OF SIGNIFICANT CHANGES
The proposed plan for LF4 was released for public comment on May 31, 1993. Public
comments on the proposed plan were evaluated at the end of the comment period.
Although no significant changes were made as a result of public comment, an element of the
preferred alternative (Alternative 3) was deleted. The groundwater extraction and treatment
contingency was deleted because the Army, in consultation with EP A, and Ecology,
determined that VES and groundwater sparging systems should be effective at remediating the
site in less than three years.
IV. SRCPP
A.
SITE NAME, LOCATION, AND DESCRIPTION
The SRCPP occupies an approximately 25-acre area between Sequalitchew Lake and Hamer
Marsh, as shown on Figure 2. Most of the SRCPP is relatively flat and surfaced with asphalt
or gravel and lies at approximately 240 to 250 feet above MSL. The western end of the
facility is lower, approximately 225 to 235 feet above MSL.
Sullivan Well lies approximately 1,800 feet east of the former SRCPP process areas.
Sequalitchew Springs lies approximately 2,300 feet nonheast of the SRCPP. Both of these
features are shown on Figure 2. Other supplemental water supply sources within the study
area were discussed in the LF4 Decision Summary.
The majority of the SRCPP facilities were demolished in 198111982, but some structures
remain. A wastewater treatment facility and fuel storage tanks remain, as do several
-------
buildings currently used for light industrial purposes. Surrounding land use is generally
recreational. The nearest residential area is:.located approximately 3.600 feet to the nonheast.
There are no known archeological, historical, or cultural resources located on or in the
vicinity of the SRCPP. Similarly, no threatened or endangered flora are known to occur on
or adjacent to the SRCPP. One federally listed threatened species, the bald eagle, has been
observed within the study area; however, bald eagles do not nest on or in the vicinity of the
SRCPP.
B.
SITE HISTORY AND ENFORCEMENT ACTIVITIES
The SRCPP operated from 1974, until its closure in 1981, as a production/research facility
designed to develop a solvent extraction technology for deriving petroleum hydrocarbon-like
products from coaL Figure 10 shows historical operation areas.
The SRCPP was initially designed to convert coal into a low-sulfur. low-ash solid (SRC-I)
product by the solvent refined coal process. The process was later modified to distill the
volatile fractions and produce liquid (SRC-II) fuel products.
Incoming coal was stored in uncovered piles at several locations. Solid products were also
stored outside awaiting shipment. as was sulfur (which was produced as a waste). Most
process fluids were conveyed throughout the plant via overhead pipes. End products of the
SRC-I process included light oil, a wash solvent, a recycled solvent. and a solid. End
products of the SRC-TI process were fractionated into light, middle, and heavy distillates.
These distillates had boiling point ranges similar to gasoline, kerosene, and fuel or motor oils,
respectively.
Byproducts of the SRC process included solid, liquid, and gaseous wastes. Solids were
reponedly disposed of off site. Liquid wastes were either directed to an on-site wastewater
treatment plant or disposed of off site. Contaminants in the solid and liquid wastes included
metals, VOCs, SVOCs including polycyclic aromatic hydrocarbons (P AHs), and oil and
grease.
Liquid wastes were collected in a system of subsurface drain lines and directed to the
wastewater treatment plant Many of the lines were later shown to have been leaking.
Treated wastewater was discharged to the wastewater lagoon. The lagoon was an unlined
natural depression located south of the facility. Overflow from the lagoon entered the
adjacent Hamer Marsh.
A network of stormwater sewers collected surface water runoff. The runoff was originally
directed to surface discharge points north and south of the facility. The runoff reportedly
contained P AHs, phenols, metals, coal solids, and other contaminantS. Part of the storm water
drain system was later rerouted to the wastewater treatment plant. CUlTendy, most runoff is
captured, treated, and routed to the Fort's sanitary sewer system.
-------
f'
~
'"
LEGEND
Boller Plant
Product Solldillcation
P,oduct Storege
Fum. Scrubb.r
Coal Sto,ao. hell
SAC-II Fueling Reck
tie at Trace Shop
Subcont,ect Maintenance Shop
OII.Speclllcallon Solid Wast.
Drum Sto,ag.
P,ocess and Product Siorage hu
1
2
3
4
5
6
1
8
9
to
Coal Receiving and Prepa,atlon
Plehealer
Slurry Dlllolvar and SI,lpplng
Mlne,al Separalor Buildings
Solvenl Recov.ry
Gaa Recov.ry and Recomp,elslon
DesullUllzallon Unit (Stretford Un II)
Synthello Oa. h.a
Minerai Realdua hea
o..alhlng Unit
11
t2
13
14
t5
16
17
18
19
20
[]J
D
11
(Ij
Wastewater Trutment Areal
Tank rRrlO
Coal Storage Areas
!><:..... .,,".,1
~
21
22
23
24
25
26
27
28
29
Conl,ol Room
htmlnlltrallon Building
Tank Farm
l"lulatlon Shop
OII/Watar Separator and OItyconlact Unit
Su,g. RelaIVol,
Aolluur tank
P,opo..d Stormwatar Retanllon Pond
Walt.wat.r lagoon
IIaunE
~
Applied Geolechnology Inc.
Geolechnica' Enginee,lng
Geology & Hydrogeologv
SRCPP: Historical Operations Areas
landfIU 4/SRCPP ROD
Fort lewis, Washington
10
I jr~~;I'~~"t~o
Or\AWt!
UEV
A.~tnO"f n
li- )!)
)
.)
OAIE
D Ap,. 13
nEVISEO
OAI(
-------
In 1979, there was a 2,OOO-gallon spill of SRC liquid fuel. Subsequent investigations of both
- soil and groundwater indicated other sources of soil and groundwater contamination might
exist at the SRCPP. Available records are limited, but indicate a large volume of
contaminated soil was excavated and removed from the spill area in late 1980 and that a
groundwater extraction program was instituted to remediate the underlying aquifer. The
duration and full scope of this program is not known.
In 1982, sludge in the wastewater lagoon was excavated as pan of facility decommissioning.
Post-removal sampling indicated PAHs in soils at the base of the excavation. The overflow
channel from the lagoon to Hamer Marsh was subsequently discovered, and soil samples from
the Marsh obtained for chemical analysis. Ecology accepted the cleanup as complete in
January, 1983, and Hamer Marsh was not remediated.
Beginning in 1981, groundwater and surface water have been monitored at the SRCPP and
nearby surface water bodies. This monitoring program was set up as part of the facility
decommissioning plan. The Fon Lewis Directorate of Engineering and Housing currently
conducts the monitoring. .
Historical infonnation indicates SRC wastes, process fluids, and fuels reached the water table
during plant operation. Soluble fractions were transponed in groundwater down gradient
toward Sequalitchew Lake and, to a lesser extent, east toward Sullivan Well. High
concentrations of some organic compounds, notably phenol, were detected beneath the
SRCPP.
Two investigations were conducted in 1991. The fIrst, an evaluation of plant records,
identified several potential contaminant sources within the former process areas. The second
included inspecting existing on-site monitoring wells and collecting groundwater samples for
chemical analysis. These samples contained low concentrations of PCE and 1,1,1-
trichloroethane.
Based on the FF A and the results of previous investigations, an RIlFS was initiated at the
SRCPP in 1991. The RIIFS characterized the nature and extent of contamination, assessed
site risks to human health and the environment, and evaluated remedial alternatives.
c.
SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY
The selected remedy is intended to address all unacceptable risks resulting from contamina-
tion at the SRCPP. It reduces risks associated with potential exposure through excavation and
treatment of contaminated soil.
Institutional controls are included to prevent construction of new water supply wells within
the fonner SRCPP process area. Long-term groundwater monitoring will verify the
effectiveness of the selected remedy.
-------
D.
SUMMARY OF SITE CHARACTERISTICS
1.
GeolOfV and Hvdl'02eOlO2Y
The SRCPP geologic investigation focused primarily on the Vashon DrifL Other deeper
deposits were encountered in a lower aquifer monitoring well boring. A description of these
deposits is presented in the corresponding LF4 Geology and Hydrogeology section. Recent
fill and four distinct Vashon Drift deposits (Steilacoom Gravel, Vashon Recessional Outwash,
Vashon Till, and Vashon Advance Outwash) were identified at the SRCPP. The general
relationship of these geologic units is shown on Figure 4.
Groundwater beneath the SRCPP generally occurs under unconfined (water table) conditions
within Vashon Drift sand and gravel. Depth bgs to the water table ranges from approximately
6 to 42 feet across the site. Although the glacial stratigraphy beneath the SRCPP is quite
complex. low-permeability Vashon Till was encountered in many borings at depths of 10 to
20 feet below the water table. This till generally appears to be a local aquitard separating the
uppermost groundwater from deeper water-bearing zones.
Hydrogeologic conditions were investigated by installing 14 new upper aquifer wells and I
lower aquifer monitoring well. These wells supplemented 11 existing, serviceable
groundwater monitoring wells.
Groundwater flow beneath the SRCPP is generally from the south to the north and northeast.
toward Sequalitchew Lake. When Sullivan Well is being pumped, a large cone of depression
develops around the well. This cone of depression extends westward between the SRCPP and
Sequalitchew Lake and intercepts some of the groundwater flowing beneath the SRCPP.
Upper aquifer groundwater ultimately discharges directly into Sequalitchew Lake or is
captured by Sullivan Well. Groundwater flow, at the lowest water elevations observed during
the study period, is shown on Figure 5.
Hydraulic conductivity of the upper aquifer beneath the SRCPP is estimated to range from
approximately 37 to 625 ft/day. Estimated horizontal flow velocities range from
approximately 3 to 135 ft/yr. This results in a travel time of approximately 15 to greater than
100 years from former SRCPP process areas to Sullivan Well, the closest water supply
source.
The lower aquifer was not characterized beneath the SRCPP. A discussion of lower aquifer
characteristics is presented in the LF4 Geology and Hvdrogeology section.
2.
Nature and Extent of Contamination
The RI investigated potential SRCPP impacts to groundwater, soil, surface water. and
Sequalitchew Lake and Hamer Marsh sediments. Air was not investigated because it was
determined that the potential for exposure was minimal due to the presence of an extensive
asphalt cover, existing structUres and the absence of YQCs.
-------
During the RI, there was no evidence to suggest that surface water flowed from the SRCPP
into Sequalitchew Lake. Therefore, surface water was not examined.
a.
Soil
Soil contamination was investigated by drilling 33 borings and excavating 20 test pits within
and around the SRCPP. Additionally, one hand auger boring was installed in the former
waste water treatment area. Soil samples were collected from each exploration and submitted
for analysis of VOCs (including fuel-range hydrocarbons), SVOCs, and metals. Soil
exploration locations are shown on Figure II. Table 9 summarizes the analytical data for soil
samples collected during the RI.
Because of the variety of sources and transport mechanisms. contaminant distribution beneath
the SRCPP is highly variable and discontinuous in nature. Fuel-range hydrocarbons, SVOCs,
and metals characteristic of SRCPP operations were detected in site soils. PCE was also
detected at several locations, although it is not specifically associated with any of the SRCPP
processes. PCE was likely used as a cleaning solvent during or subsequent to plant operation.
Generally, low concentrations of PAHs were detected throughout the SRCPP, with individual
P AH concentrations typically not exceeding 2 milligrams per kilogram (mglkg). The highest
concentrations of P AHs were detected at the waste drain intersection near the center of the
process and product storage area. at the tank farm, at the flare knockout drum pad, and in the
wastewater treatment area (specifically, near the oil/water separator). The vertical distribution
of P AHs was quite variable, with the highest concentrations near the surface in some areas,
and near the water table in others. Seven P AHs are carcinogenic; the remainder are
noncarcinogenic. All seven carcinogenic P AHs were detected at the SRCPP.
Fuel-range hydrocarbon compounds have a distribution similar to the P AHs, except high
concentrations were also detected near the current fueling area southeast of the tank farm.
The detections in this area may in pan reflect post-SRCPP-c1osure fuel oil spills. Fuel oil
and jet fuel are currently stored and dispensed from the SRCPP tank farm. Leaks and spills
from fueling operations have contaminated soils in the area.
Three types of VOCs were detected at low concentrations in SRCPP soil: alkylbenzenes.
chlorinated hydrocarbons, and an oxygenated hydrocarbon. Toluene, xylenes, and PCE were
most commonly detected. Although these compounds were not as widely distributed as the
P AHs, their distribution pattern was similar.
Metals concentrations at greater than background levels occur in the following areas:
~
Coal storage area - elevated barium and nickel; all metals were ek"ated in surface
soils at several locations.
~
Stormwater outfalls - elevated iron, manganese, arsenic, barium. chromium, lead.
nickel. and zinc.
-------
LEGEND ;;:';' .,t:;;::i,;:,~::'==':="=: :;'::, '".'.. ';- . / \,
. \ ~,. ... n' .'
Drilled Boring number and ,II ':.. I, '. "'. ,,:,::. .,'''::". . / " ) , '
B33. approximate location J.,f II, TP4 ... I" '''', '" 1,-",-,-,,-,,' ."", ,- " "
HA2 Hand Auge~ Boring number::/ \\' B~2 /"'. -"'"'' ( I,:"" I ./ " "'" , -,...-....,.- ':," ,.,- ',' ", i'
. and approximate location //:~ I ( '''''." 'J' :," -- :1" i I ,.,...", """,""--,- ,.' .,' \ \ .
TP5. Test Pit, number a~d ,\!, B~3 '.: . , If ,': ";'P3 , ' I ...- ." - .,.-'- (~) ( (8RC-MW~2)\,'
approximate location 1/ 1\ , I TP 1 I!, . ' " i\ 82,. \. '
I. I . TP99 ' , .
1 \ . I B14 . ,B30 929 /.. J '. \' \ \
\ \ .HA21 ' . . --", ' \
\ \., "- I HA20.' ," ' "', I ,\., '
,I \ ---......- I""': .TP18 , '\' '-\ ( \ '" '.
TP5 B137~:1 /91!J.~P19-"1 II ~A2~- ~H~23 \ \\ '\ t,." I
" , . .,' ,,' (SRC.MW5) .,1-",;- I ' '- TP157 HA28 HA27 \ ' \ \, TPI
, oJ. I-,:~.~':,:~-,::.:..::,::' .' ::;~P20 '/ li~~~-~J1" "'~5 "I ~~~~.~P14 'I ~Pj:;;{1 I! \':--.\,.\ '\\\ "',. ,.'
II ", '''. .,,,.:;...,, ..J (I I . I TP16 ,J TP , 827,'"
:', ':,.. " '\... '~"u' ~:::,;:." B18'. i~' 0 HMO ~) ~ i, ,,', I.. 2 B28 TP~O \ ,-,...;,.;.,;.~~_.,\r'. ,.- ..... "
'..:: ''::''':'''''' )., , ,,0,. / U () 86 (831 .88 /1. " . - ':, '. ,..-
'" ... ..' \ ( ( ) / 'B21 .. I I,'. I, I \
,,"""",,/...,...,..... ----.. 810 ) (-')8:'~'~_'()~" I ., . .,'". HA25/" " '. / ,.".' ',' ,
.. "~-~"'~""""rl'II;:,;;~';~~~;~;~~:;;:::~::!~::~~!~~:~;s;;:..~~.'..",,:.~:., j "" ~~::~~"-"~"111 81;"T~13' , / .87 ~3 -82',"",: ,~ ~-,:~, ' '
., . . ""-. "'h"~.I"U""""'t',- "'J':;:;,...I..,""".,,,,,,,, . 822812' I . i ",1 ~
. "'. ..~ "" --'...:- -.. -.. - ..- '."'III";:::::~,::~"~",,,.t-"f""', ~._.;,,:.:;'.::.t',,/"".::. ''fl'. .,' ""'1 81 82 " ',, B 8\ TP~.....~~',~::"" (SRC"'WI)
-. -. - - .:- "". -. .... - .... - ..., ,.".t:::;';:;~:i "'.,..,..7~D_.:.!:~~.t:, .:' .', .'::':"~I I '''''''' . . ~ \ 34 \ .,.....",.~. "'''r.' ...-,,-' .
HA3.- 'HAS -"'-.."" "'th)~.."''''" ~".."..,.... 't.,- '" 'f"'" . \ ) .."......... ......~
I . -""""--'-..... ''''''''.......... "t'",.~:::::::...t",..""""""'I'" ,., .! .: .~............, .
" " ~ .. '. --, ""~. ""', "':::::""',\,/1 ",' .84 ..-,...."
HA7.V'-HA "". .., "'-..~, "" , '''',,; ~
HA2'. ' H 9 ''','', "'.,
.HA4',. ..
" HAS. ~ ~P~' " . . '" - ,
, . ' TP7
; HA6 "
. .
"', "'; ::::::':::::::,~.:.~::::;..,...,...
""f....:""r,.,
.,,' ".~,:::::::~::: ::'"
"'. .
~.>..>....
814 (SRC.MW14)
.
HA12
" I
1 ,
i/
. '
, ,.
, . iHA15
\
. \
HA13
.. '
.'
. HA 11
"
;0'-
(SRC-MW2),./ "
823.' -' '
.,,- /'
,/ ,"',
o
200
.
\
.' ,
HA 14 \.
"
- . .. - ... .. ~
"'. "
"'.. -,'" ......
... '. .........
Scal. In Feet
.,:~
~ Applied Geotechnology Inc,
Geotechnical Engineering
Geology & Hydrogeology
SRCPP: Boring and Test Pit Locations
Landfill 4/$RCPP ROD
Fort Lewis, Washington
FIGURE
..
(
\
Noto: HA 10 located I
200' west 01
HAIl I
I
11
.
'"
.
'"
Jon NUMBER
14,340,100
DRAWN
DFF
"PPROVE 0
~DL.
DATE
22 Jan 83
REVISED
-------
Table 9
SRCPP: Compounds Detected in Soil, Concentration Ranges,
and Frequency of Detection
Landfill 4/SRCPP RCX)
Fort Lewis, Washington
~.....
Semivolatile Organic Compounds -
Pol c clic Aromatic H drocarbons
Acenaphthene <0.18-69
Acenaphthylene <0.18-1.05
Anthracene <0.18-30
8enzo (a) anthracene <0.18-12
8enzo (b) fluoranthene <0.18-17
Benzo (k) fluoranthene <0.18-5.3
Benzo (g,h,O perytene <0.18-5.7
Benzo (a) pyrene <0.16-8.6
Chrysene <0.18-19
Dibenzo(a,h)anthracene <0.16-1.2
Dibenzofuran <0.16-99
Auoranthene <0.18-130
Fluorene <0.16-64
Indeno (1.2,3-cd) pyrene <0.16-3.3
2-MethyinaphthaJene <0.16-270
Naphthalene <0.16-290
Phenanthrene <0.16-410
Pyrene <0.18-79
Semivolatile OrQanic Compounds - Others
Aniline 0.11 J -1.4
Benzoic Acid <5.3-0.49 J
bis (2-EthylhexyQ phthalate 0.041 J-19
Di-n-octylphthalate <0.16-0.15 J
2,6 - Dinitro toluene <0.16-0.52
4,6 - Dinitro-2-methyl phenol <0.91-0.95 J
N-Nitrosodimethylamine <0.18-0.14 J
Phenol <0.18-1.2
2-Methyl phenol <0.18-0.41 J&
4-Methyf phenol <0.18-0.575 J
2.4-Dimeth I henol <0.16-0.36 J
Volatile OrQanlc Compounds
Benzene
Chloroform
Ethytbenzene
2-Hexanone
T etrachlorcethene
1,1,1 -Trichloroethane
Trichloroethene
Toluene
Total Xylenes
Page 1 of 2
<0.052-0.30
<0.054-0.3
<0.052-12
<0.052-11
<0.052-0.98
<0.052-0.20
<0.052-0.12
<0.052-5.2
<0.052-34
1/55
2/85
8/85
1/55
17185
1/85
2/85
13/85
15/65
30/159
8/159
41/159
42/159
53/159
33/159
48/159
48/159
54/159
14/159
43/159
61/159
37/159
43/159
40/159
32/159
73/159
69/159
1/159
1/159
8/159
1/159
1/159
1/159
5/159
1/159
7/159
-------
Table 9
SRCPP: Compounds Detected in son, Concentration Ranges,
and Frequency 01 Detectio,\.
Landfill 4ISRCPP ROO
Fort Lewis, Washington
~.~fll;.ill1t.
Total Metals
Antimony
Arsenic
Barium
8erylium
Cadmium
Chromium
Copper
Iron
Lead
Manganese
Mercury
Nickel
Selenium
Silver
Zinc
<0.26-3.25
0.78-12
22-84
<0.26-0.52
<0.26-2.5
3.8-19
8-1700
6200-37000
<1.54-120
110-500
<0.10-0.11
6.7-26
<0.16-0.90
<0.26-1.5
13-220
7/69
69/69
69/69
10/69
5/69
69/69
69/69
69/69
69/69
69/69
1/69
69/69
3/69
11/69
69/69
Notes:
a) All measured values are below method reporting limit (MRL).
J - Estimated concentration.
mg/kg - Milligrams per kilogram.
Frequency of Detection is figured as the number of samples with detections divided by the
total number of samples taken.
A value expressed with < indicates the number falls below the MRL
A sample location where a duplicate was taken counts as one sample in the Total Samples
value. If the sample, the duplicate, or both had a positive detection, it counts as one positive
detection.
-------
Table 10
SRCPP: Compounds Detected in Upgradient and Downgradient Upper Aquifer Groundwater,
Concentration Ranges, and Frequency of Detection
Landfill 4/SRCPP ROO
Fort Lewis, Washington
_~tl1\1._.
Volatile OrQanic Compounds
Benzene
Chloroform
1,1-Dichloroethane
Ethylbenzene
Tetrachloroethene
Toluene
1,1 ,1 -Trichloroethane
Trichloroethene
Semivolatile Organic Compounds -
Polycyclic Aromatic Hydrocarbons
Anthracene
Auoranthene
Phenanthrene
Pyrene
1Y9lY.
<0.5-0.6
<0.2-6.1
<0.2-0.7
<0.5-0.9
<0.2-2.9
<0.5-0.7
<0.2-6.2
<0.2-0.4
~
<0.01 -0.01
<0.01-0.12
<0.01-0.14
<0.01-0.25
Semivolatile OrQanic Compounds - Others
Dibenzoturan
2,4-0imethylphenol
Di-n-octylpthalate
4 -Methylphenol
Phenol
{ygl!J
<10-1.4 Ja
<10-4.3 Ja
3.4 J - 25
<10-1.4Ja
<10-2.3 J a
Total Metals
1m9&l
0.48-360
<0.005-0.0075
<0.005-0.067
<0.010-2.6
<0.002-0.011
16-120
<0.0002-0.0017
<0.010-0.30
<0.010-0.71 J
<0.010-0.68
0.29-440
<0.003-0.16
4.6-140
<0.010-11
<0.0002-0.0049
<0.010-0.73
Metals
Aluminum
Antimony
Arsenic
Barium
Beryllium
Calcium
Cadmium
Cobalt
Chromium
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Page 1 of 2
2122
9/22
2122
1/22
6/22
2122
4/22
5/22.
1/22
4/22
9/22
12122
1/22
1/21
10/24
1/20
1/21
22122
6/22
15/22
20/22
10/22
22/22
20/22
17/22
21/22
20/22
22/22
19/22
22/22
22/22
5/22
21/22
I
Dissolved Metals I
1m.9lY.
<0.05-6.7
<0.005-0.008
NO
<0.010-0.16
ND
2.6-33
<0.0002-0.0003
NO
<0.01-0.01
<0.01-0.008 J a
0.032-6.7
<0.003-0.0032
1.1-13
<0.01-2.8
NO
<0.01-0.042
16/22
7/22
0/22
6122
0/22
22122
3/22
0/22
1/22
1/22
19122
0/22
22122
22122
0/22
-------
Table 10
SRCPP: Compounds Detected in Upgradient and Downgradient Upper Aquifer Groundwater,
Concentration Ranges, and Frequency of Detection
Landfill "ISRCPP ROO
Fort Lewis, Washington
l.fJI.-
Metals (cont)
Potassium
Silver
Sodium
Vanadium
Zinc
Total Metals
1!!!.9n:l
0.98-27
<0.005-0.0072
5.8-31
<0.010-0.76
<0.010-1.2
22122
3/22
22/22
19/22
22122
Dissolved Metals
1!!!.9n:l
0.64-2.6
<0.005-0.0073
3.7 -31
<0.01 -0.011
<0.01 -0.05 J
22/22
S/22
22J22
1/22
7/22
Notes:
a) All measured concentrations less than method reporting limit (MRl).
J - Estimated.
NO - Not detected.
ug/L - Micrograms per liter.
mg/L - Milligrams per liter.
Frequency of Detection is figured as the number of samples with detections divided by the total number of samples taken.
A value expressed with < indicates the number falls below the MRL
A sample location where a duplicate was taken counts as one sample in the Total Samples value. If the sample. the
duplicate. or both had a positive detection, it counts as one positive detection. Total Samples is equal to the total number
of samples in Round 1 plus Round 2.
Background wells not considered include MW2. MW3. and MW14.
-------
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LEGEND
SRC.MW11
.
Monitoring Well number
and approximate location
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Applied Geotechnologv Inc,
Geolechnical Engineeflllg
Geology & Hydrogeology
~
SRCPP: Monitoring Well Locations
Landfill 4/SRCPP ROD
Fort Lewis, Washlnglon
o
r
400
:J
.
'"
.
01,
Scale In Feol
JOB NUMBER
14,340.100
onAW'~
orf
APPROVED
1H11L
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REVISED
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-------
~
Process and product storage area - elevated arsenic and zinc; all. metals except
:. selenium and thallium are elevated at Test Pit (TP) 3 (at 1 foot), and arsenic. barium.
beryllium. chromium. nickel. and zinc are elevated at TP2.
The distribution of contaminants in wastewater lagoon soils indicates the most heavily
contaminated soil was removed with the sludge during the 1982 cleanup. Only low
concenttations of P AHs and fuel hydrocarbons CUITently remain. except at the outfall. Soil
fro~ this area showed significantly elevated P AH and fuel hydrocarbon concentrations when
compared to the other wastewater lagoon soils.
P AHs and fuel hydrocarbons were also detected in Hamer Marsh soil. However, the P AH
distribution and fuel fingerprint indicate they are probably derived from a different source.
The RI identified storm water runoff, which passes through the area from the Fon' s
stonnwater treatment facility, as the likely source. Consequently, Hamer Marsh
contamination was not considered funher in the Rl/FS.
b.
Groundwater
Groundwater samples were collected from 14 upper aquifer and II lower aquifer monitoring
wells in April and June 1992. Well locations are shown on Figure 12. The sampling rounds
were timed to approximate "wet" and "dry" season conditions. All samples were analyzed for.
VOCs, SVOCs, PAHs, and total and dissolved metals. A limited third sampling, addressing
metals, was conductecI in JanuaryIFebruary 1993. Table 10 summarizes the analytical results
for groundwater samples collected during the RI. .
RI results indicate that current SRCPP impacts are generally limited to the vicinity of the
'fonner process area. Sullivan Well water shows no discemable impact from SRCPP
operations.
RI soil boring data indicate residual SRC product is present at several discrete locations.
These hydrocarbons are probably related to historical spills or infiltration related to pipe
leaks. RI groundwater quality data, however, indicate few hydrocarbons are being transported
in groundwater. Low concentrations (less than 10 pg/L) of PAHs, mostly pyrene and
phenanthrene, and VOCs (generally less than 1 pg/L), mostly benzene. ethylbenzene, toluene,
TCE, and PCE, were detected in upper aquifer groundwater beneath and downgradient of the
SRCPP. Chloroform, which is a by-product of chlorination, was also detected in
groundwater.
Metals were also detected in the upper aquifer. Dissolved metals concentrations were either
within background ranges or nondetectable, except for sodium, which is typically present in
groundwater due to the natural equilibrium between groundwater and geologic materials.
Total metals concentrations were also within their background ranges except for lead, which
is present at levels significantly above background. at monitoring well 13.
-------
c.
Sediment
Sequalitchew Lake sediments were evaluated by collecting five composite shoreline area
sediment samples, three from areas immediately downgradient of the SRCPP (S2, S3, S4) and
two from areas believed to be unaffected by SRCPP operations (S 1, S5). Sequalitchew Lake
composite sampling areas are shown on Figure 13. Composite sediment samples were
analyzed for VOCs, SVOCs, and metals. Table 11 summarizes the analytical data from the
sediment samples collected during the Rl.
Sequalitchew Lake sediment samples collected immediately downgradient of the SRCPP have
higher metals and P AH concentrations than do sediment samples collected in adjacent areas.
The most likely cause of the elevated concentrations is precipitation of metals and scavenging
by organic-rich sediments of contaminants from groundwater flowing beneath the SRCPP and
discharging to Sequalitchew Lake.
SRCPP impacts to the adjacent wastewater lagoon and Hamer Marsh sediments were
investigated by advancing 14 hand auger borings from which soil samples were collected.
Hand auger locations are shown on Figure 11. Soil samples were analyzed for VQCs,
SVQCs, metals, and fuel hydrocarbons.
Due to the Ecology directed cleanup conducted in 1982, only low concentrations of P AHs and
fuel hydrocarbons currently remain in the lagoon, except near the original outfall from the
SRCPP. The one sample from this area showed significantly higher PAH and fuel
hydrocarbon concentrations.
P AHs and fuel hydrocarbons were also detected in Hamer Marsh sediment. However, the
P AH distribution and fuel fingerprint indicate they are probably derived from a different
source. Stormwater runoff passing through the area from the Fort's storm water treatment
facility is the likely source.
E.
SUMMARY OF SITE RISKS
The Baseline RA for the SRCPP, considered human health and ecological risks. The risk
assessments were conducted in accordance with EPA's Risk Assessment Guidance for
Supeifund, Volume J: Human Health Evaluation Manual and Volume 2: Environmencal
Assessment Manual, and EP A national guidance. The RA methods and results are
summarized in the following sections.
1.
Human Health Risks
The human health RA evaluated potential risks associated with exposure to chemical
contaminants from the SRCPP. The assessment considered potential exposure to SRCPP
contaminants in soil and groundwater. Air was not included in the quantitative RA because it
was determined that the potential for exposure was minimal due to the presence of an
-------
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l' ':'''''''''''''''' ..-_...~...-..' . I
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t...- ,'/ \~, .~,) """"''';'''
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Samplo locallon
(p
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fiGURE
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Applied Geotechnologv Inc.
Geotechnical Engineering
Geologv & Hydrogeology
SRCPP: Sediment Sampling Locations
landfill 4/SRCPP ROD
Fort Lewis, Washington
13
'"
Jon NUMBER
14,340,100
ORAWtl
DFF
APPROVEO
APe
OlltE
22 Jan 93
REVISED
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..
-------
Table 11
SRCPP: Compounds Detected in Sequarltchew Lake Sediments,
Concentration Ranges, and Frequency of Detection
Landfill 4ISRCPP ROCt -
Fort Lewis, Washington
Ijt~~~-
Semivolatile OrQanic CompOunds
Benzoic acid
4-Methylphenol
NapthaJene
Phenanttvene
Pyrene
<1.29-0.5 J.
<0.20-0.25
<0.20-0.5 J
<0.20-0.35 J
<0.20-0.25 J
1/5
1/5 .
1/5
115
115
Total Metals
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
Copper
Iran
Lead
Manganese
Nickel
Silver
Zinc
<0.39-0.38
2-13
21-130
<0.15-0.61
<0.39-1.6
10-58
10-66
3600-26000
15-140
88-1100
8.9-51
0.74-3.9
8.5-24
1/5
515
5/5
3/5
315
5/5
515
5/5
5/5
515
515
5/5
515
Notes:
a) - All measured values below method reporting limit (MAl).
J - Estimated concentration.
mg/kg - milligrams per kilogram.
Frequency of Detection is figured as the number of samples with detections divided by the
total number of samples taken. .
A value expressed with < indicates the number falls below the MRL
A sample location where a duplicate was taken counts as one sample in the Total Samples
value'. If the sample. the duplicate. or both had a positive detection. it counts as one positive
-------
extensive asphalt cover, existing structures, and the absence of VOCs. Sediment and surface
water was similarly not included because the impacts to Sequalitchew Lake and its sediments
are not significant
Both carcinogenic and noncarcinogenic risks were evaluated. Risks were estimated for
current and future land uses in the vicinity of the SRCPP.
To ensure that potential health risks would not be underestimated, a conservative approach
was used as recommended in EPA's guidance documents. Reasonable conservative estimates
and assumptions were used to enhance confidence in the conclusions of the RA.
a.
Identification of Contaminants of Concern
COCs were determined for the SRCPP based on contaminant occurrence and distribution in
the environmental media and a risk-based screening approach. The COCs for the SRCPP are
shown in Table 12.
b.
Exposure Assessment
1.
Exposed Populations
Exposure pathways were evaluated for the following receptors:
Current Use:
Military residents
SRCPP Facility Employees
Future Use:
On-site residents
Adjacent residents
11.
Exposure Pathways
Refer to Table 13 for the exposure pathways evaluated. Predictive modeling indicates a
moderate potential for adverse impact from carcinogenic PAHs via leaching to groundwater
should site pavements be removed.
111.
Exposure Point Concentrations
Groundwater:
A verage and reasonable maximum exposure concentrations were estimated based on field
measurements. Groundwater exposure point concentrations were used to quantify the risks
due to ingestion of drinking water, dermal absorption during household use, and inhalation of
-------
VOCs during household use. Data from different groupings of groundwater wells were used
to estimate future exposures. Sullivan Well data were used for current scenarios.-
The dissolved fraction of metals in groundwater was used to estimate exposure point
concentrations at the SRCPP. Total metal concentrations were considered most representative
of silt conditions adjacent to the monitoring wells. Dissolved metal concentrations were
considered most representative of exposure point concentrations for the ingestion of
groundwater from a water supply well.
Average and reasonable maximum exposure concentrations are listed in Table 14.
Soil:
A verage and reasonable maximum exposure concentr,,:tions were estimated based on field
measurementS. Soil exposure point concentrations were used to quantify the risks due to
ingestion of soil. dermal contact with soil, and inhalation of fugitive dust. They were also
used to estimate concentrations of volatilized VOCs in ambient air for on-site residentS.
Different groupings of soil analytical data were used to estimate exposure point
concentrations. The principal distinction was whether the pavement cover was assumed to be
intact or not.
Average and reasonable maximum exposure concentrations are listed in Table 15.
Chemical Intake by Exposure Pathway:
Chemical intakes for each exposure pathway were calculated based on the exposure point
concentrations and other exposure parameters such as water ingestion rates, inhalation rates,
dermal absorption rates, body weights, exposure frequencies and durations. Reasonable
maximum exposure calculations for the SRCPP RA used values from the Standard Default
Factors document (OSWER Directive No. 9285.6-03).
c.
Toxicitv Assessment
The toxicity assessment methodology is as described in the LF4 Toxicitv Assessment section.
Table 16 listS the toxicity values for the SRCPP COCs.
d.
Risk Characterization
The risk characterization integrates the information developed in the toxicity assessment and
exposure assessment to characterize the carcinogenic and noncarcinogenic risks associated
with contaminant concencrations detected at the SRCPP. Acceptable risk ranges for
carcinogens and noncarcinogens are as described in the LF4 Risk Characterization section.
Table 17 provides a summary of estimated health risks for each receptor and pathway.
-------
Table 12
SRCPP: Contaminants of Concern
Umdflll 4/SACPP ROD
Fort Lewis, Washington
11111__-
Soil
CarcinoQenic
Polycyclic Aromatic Hydrocarbons
8enzo (a) anthracene
Senzo (b) fluoranthene
Senzo (k) tluoranthene
Benzo (a) pyrene
Chrysene
Dibenzo (a,h) anthracene
Indeno (1.2.3-cd) pyrene
(mQ!kQ)
<0.18-12 421159
<0.18-17 53/159
<0.18-5.3 33/159
<0.18-8.8 48/159
<0.18-10 54/159
<0.18-2.5 14/159
<0.18-3.3 43/159
(mQ!1
-------
Table 13
SRCPP: Exposure Scenario Matrix
Landfill 4/SRCPP ROD
Fort Lewis, Washington
...:.:.R:~fi~.~~'..~.po~Jr~. 'S~~~.~:~I~.~.....
. Fut~te':.~.~~~:~i~'.:.~~:~nl.rt~~.::::i......;.:.
?~ii&~~il"
) iifi~~~i;'~ffi;
SC~h~tl()S;'.:.
.:....;..~~~.~;'~!¥.::.;i:i;!!i:i.:.:.
~,~j!~i!il
Soil
Ingestion
Dennal Contact
Inhalation of Fugitive Dust
Inhalation of Volatilized 5011 Contaminants
N/A
N/A
Yes
No
Yes N/A
No No
Yes No
Yes No
N/A
No
Yes
No
Q!oundwat~[
Ingestion Yes Yes Yes Yes
Dennal Contact No No UNC No
Inhalation of Volatilized Groundwater VOCs Yes N/A Yes Yes
Notes:
N/A - Pathway Is not applicable for this receptor population.
Yes - Risk and/or hazard was quantified.
No - Risk and/or hazard was not quantitlfled.
UNC - High degree of uncertainty associated with this pathway; see Baseline RA Report.
VOC - Volatile organic compound. .
Page 1 of 1
01-Dep-93
-------
Table 14
SRCPP: Groundwater Exposure Point Concentrations
Landfill 4/SRCPP ROO
Fort Lewis, Washington
Upper Aquifer, Using Monitoring Wells MW8 and MW12 (Influencing Sullivan Well)
li~I.~lil!~!ail!
Volatile OrQanic Compounds
Benzene
Chloroform
Tetrachloroethene
Trichloroethene
0.25 D
2.7
0.1 D
0.2
Semivolatile Orqanic Compounds
Dibenzofuran
Di-n-octylphthalate
5 D
5.2 D
Total Metals
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
Manganese
Mercury
Nickel
Selenium
Silver
Vanadium
Zinc
3.5 D
2.5 D
110
1 D
0.41
62
510
0.1 D
50
2.5 D
2.5 D
43
91
No Associated Toxicity Values
Cobalt
Copper
Lead
Phenanthrene
11
22
4.4
0.005 D
Notes:
0.25 D
3.0E+12
0.1 D
2.2
5 0
40
12
2.5 D
5.0E+09
1 D
3.5
10,000,000
8,500
0.1 D
1,800,000
2.5 D
2.5 D
30,000,000
12000
220
32,000
440
0.005 D
\%~[:
:0.4.
0.25 D
6.1
0.1 D
0.4
<::10
9.3 D
5 D
9.3 0
):<~~:
. i~~i~
./00 o)\.1..~()i:
'::'::::j~O~~
. nn.=~:
\~~,~~
6.5
2.5 D
270
1 D
0.82
150
1,000
0.1 D
92
2.5 0
2.5 0
110
160
n):23
i:~rin
<0.0.'
23
55
10
0.005 D
Shaded value indicates the lower of the UCL and maximum concentrations.
a) Mean is calculated arithmetically using one-half the method reporting limit (MAL) for nondetects.
b) Maximum concentration is the maximum concentration measured in Upper Aquifer wells SAC-MW8 and MW12.
D - Indicates the calculated value is below the MAL due to the number of nondetects.
RME - Reasonable maximum exposure is the lower of the UCL and maximum concentrations.
UCL - Upper confidence limit of the mean calculated using log-normal transformation of the data.
ug/L - Micrograms per liter.
< indicates the maximum value is the MAL.
-------
Table 14
SRCPP: Groundwater Exposure Point Concentrations
Uindfill 4/SRCPP ROD
Fort Lewis, Washington
Metals at Sullivan Well
. . .
... ........,. ,".,... . . ...... . .. ..
..... ''''''''n'' .... ..""'''''''''''''''''''''''''''' ,p'" ....
. .................. .. :-:::':::::::::::::,:.::::':::::::'::::;;:-:::::-::-::;':';:,::::
l_iJi~l~t~1
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
Manganese
Mercury
Nickel
Silver
Vanadium
Zinc
2.5 D
1.5 D
3.0 D
0.50 D
0.14 D
6.0 D
2.2 D
0.25 D
6.5 D
9.0 D
4.5 D
23
2.5 D
1.5 D
4.0 D
0.50 D
0.14 D
6.8 D
1.8 D
0.25 D
6.5 D
10 D
5.0 D
6.4
. No Associated Toxicitv Values
Cobalt
Copper
Lead
2.5 D
10 D
1.4 D
2.5 D
10 D
1.5 D
Notes:
a) Mean is the average of Sullivan Wells 12A and 12B using one-half the
method reproting limit for nondetects; RME concentration was not
established due to limited data set.
D - Value is below the method reporting limit.
ug/L - Micrograms per liter.
-------
Table 14
SRCPP: Groundwater Exposure Point Concentrations
Landfill 4/SRCPP ROD
Fort Lewis, Washington
Upper Aquifer, Using On-Site Monitoring Wells MW4, MW5, MW6, MW7, and MW8
11~~11~1~111~~}t~~i~i'~if~.
Volatile OrQanic Compounds
Benzene
Chloroform
Tetrachloroethene
Trichloroethene
0.33 D
0.69
0.69
0.160
OA3:
4.2
4.7
.0.24'
Semivolatile OrQanic Compounds
Dibenzofuran
Di-n-octylphthalate
5.9 D
6.6 0
.7.1. D
..11,
Total Metals
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
Manganese
Mercury ,
Nickel
Selenium
Silver
Vanadium
Zinc
3.2.D
12
510
2.2
0.65
130
2500
0.18 D
130
'2.5 0
3.0 0
220
180
.~~9 D
.. '.. \....:.:'~:\'~~':::
1400
:.,::il!:fi~:
4700
<9:?~
')25Q:
;:~:g
780
:,.'.380:,:
No Associated Toxicity Values
Cobalt
Copper
Lead
Phenanthrene
57
130
25
0.029
210
450
..,,\6t:::
0~1A:
Notes:
0.7 0.43
2.6 2.6
2.9 2.9
0.4 0.24
14 7.1
25 11
5.9 4.0 0
40 38
:.1045 1100
4.7 3.8
1.7 1.1
330 300
<3950: 4000
0.61 0.29
310 250
<5 2.5 D
5.8 3.6
580 580
420 380
140 140
29S' 300
74 61
0.14 0.14
Shaded value indicates the lower of the UCL and maximum concentrations.
a) Mean is calculated arithmetically using one-half the method reporting limit (MAL) for nondetects.
b) Maximum concentration is the maximum concentration measured in Upper Aquifer wells SAC-MW4, MWS, MW6,
MW7, and MW8.
o - Indicates the calculated value is below the MAL due to the number of nondetects.
AME - Aeasonable maximum exposure is the lower of the UCL and maximum concentrations.
UCL - Upper confidence limit of the mean calculated using log-normal transformation of the data.
ug/L - Micrograms per liter.
< indicates the maximum value is the MAL.
-------
Table 14
SRCPP: Groundwater Exposure Point Concentrations
Landfill 4/SRCPP ROD
Fort Lewis. Washington
leached PAHs, Using On-Site Soil Samples
Benzo (a) anthracene
Benzo (b) fluoranthene
Benzo(k) fluoranthene
Benzo(a) pyrene
Chrysene
D ibenzo (a.h) anthracene
Dibenzofuran
Fluoranthene
Indeno(1.2.3-cd)pyrene
Naphthalene
Phenanthrene
Pyrene
Notes:
si..tilli,
3.0E-05
9.1E-05
3.1E-05
6.7E-06
3.3E-04
3.6E -06
6.8E-03
6.6E -03
1.1 E-OS
8.0E-02
2.8E-02
1.0E -02
<1.0E-05
<1.0E-05
<1.0E-OS
<1.0E-OS
<1.0E-05
<1.0E-05
5.9E-03
1.2E -OS
<1.0E-OS
< 1.0E -05
2.9E -OS
3.8E-OS
a) Mean concentrations estimated using 2% soil organic carbon content and mean soil PAH
concentrations form Table 15. .
b) Detected using EPA Method 8310 (except dibenzofuran): <1.0E-OS represents method reporting limit.
mg/L .... Milligrams per liter.
-------
Table 14
SRCPP: Groundwater Exposure Point Concentrations
LandfiIl4/SRCPP ROD
Fort Lewis, Washington
Upper Aquifer. Using On-Site Monitoring Wells MW4. MW5. MW6, MW7, and MWB (Dissolved Metals)
,.,....-..;:;::';';:::. .....'" ':::'::;:;'::;:::::;:;'" .... ".:.;..;.';"::;::'::::::;:;::'';":::':';';':':':';'' ....':':':':"':'.':::":'. ,"."..' ,.:.:.....-..:::;.,.:;:;;,:,:;";........,,-
$€~f~}I~lJ~~!~lf~l~ij~~~~~ t1~j~i~;\
Volatile Orqanic Compounds
Benzene
Chloroform
1,1 -Dichloroethane
Tetrachloroethene
Trichloroethene
Semivolatile Orqanic Compounds
Dibenzofuran
Di-n-octylphthalate
Dissolved Metals
Arsenic
Barium
Beryllium
Cadmium
Chromium
Manganese
Mercury
Nickel
Silver
Vanadium
Zinc
No Associated Toxicity Values
Cobalt
Copper
Lead
Phenanthrene
Notes:
0.33 D
0.69
0.19 D
0.69
0.16 D
5.9 D
6.6 D
2.5 D
7.6
1 D
0.12 D
5 D
690
0.1 D
8.6 D
4.4 D
5 D
12 .
5 D
5.3 D
1.5 D
0.029
','.0.43'"
4.2
0.32.
4.7
0.24
7.1 D
1J
D
D
D
0.7 0.43
.:'2.6.. 2.6
0.7 0.3
.. ..
",:2.9 2.9
0.4 0.24
14 7.1
25 11
<5 2.5 D
19 11
<:2 1 D
0.34 0.16 D
<:10 5 D
\2;800 2,800
<:0.2 0.1 D
41 13
7.6 6.7 D
<:10 5 D
20 19
<:10 5 D
8.4 D 6 D
<:3 1.5 D
0.14 0.14
D
D
D
o
D
Shaded value indicates the lower of the UCL and maximum concentrations.
a) Mean is calculated arithmetically using one-half the method reporting limit (MRL) for nondetects.
b) Maximum concentration is the maximum concentration measured in Upper Aquifer wells SRC-MW4. M'o'.'5. MW6,
MW7, and MW8.
-- Not estimated.
D - Indicates the calculated value is below the MRL due to the number of nondetects.
RME - Reasonable maximum exposure is the lower of the UCL and maximum concentrations.
UCL - Upper confidence limit of the mean calculated using log-normal transformation of the data.
ug/L - Micrograms per liter.
< indicates the maximum value is the MRL.
-------
Table 15
SRCPP: Soil Exposure Point Concentrations
Landfill 4/SACPP AOD
Fort Lewis, Washington
On-Site Unpaved Soil
. .. ...'" d.... ..". ..... "." ......
. .......... ....... .. .... ...." ". .,........., ........ '" ........
i;c~~~~~ti~I'~;III~li.~1~~
Volatile OrQanic Compounds
Tetrachloroethene
0.12
.'0.18.
Semivolatile OrQanic Compounds
8enzo(a)anthracene
8enzo(b)fluoranthene
8enzo(k)fluoranthene
8enzo(a) pyrene
Chrysene
D ibenzo (a,h) anthracene
Dibenzofuran
Fluoranthene
Indeno(1,2,3-cd)pyrene
Naphthalene
Pyrene
0.44
...1.0
0.36
.0.64
.0.96
0.16 D
0.32
..,:A2'.
0.34
0.30
9.0
.....
0.45
1.0
0.34
0.61
0.91
().17 D
.,.0.38
3.6
(0~3'7)
ii;30~
. .
Metals
Antimony
Arsenic
8eryUium
Cadmium
Manganese
0.24 D
3.7
0.21 D
0.17 D
230
.~;25D
....::~~~:
'\)::::\!ir9~5.::~ D
:)0:19.' D
......\270.
No Associated Toxicity Values
Acenaphthylene
8enzo (g,h,i) perylene
Lead
2-Methylnaphthalene
Phenanthrene
Lp.16 D
0.41
0.16 D
;0.44
12
0.36
0.94
... ..
Notes:
0.98 0.18
4.9 0.45
17 1.0
5.3 0.36
8.8 0.64
19 0.96
1.2 0.17 D
1.9 0.38
130 4.2
3.3 0.37
4.1 0.31
240 11.2
2.3 0.25 D
12 4.9
0.52 0.25 D
0.50 0.19 D
500 270
1.0 0.16 D
5.7 0.44
120 16
5.3 0.37
7.0 1.7
Shaded value indicates the lower of the UCL and maximum concentrations.
a) Mean is calculated arithmetically using one-half the method reporting limit (MAL) for nondetects.
b) Maximum concentration is the maximum concentration measured in all samples.
D - Indicates the calculated value is below the MRL due to the number of nondetects.
mg/kg - Milligrams per kilograms.
RME - Reasonable maximum expbsure is the lower of the UCL and maximum concentrations.
UCL - Upper confidence limit of the mean calculated using log -normal transformation of the data.
Concentrations were estimated using chemical data from soil borings 83, 84, 87. 89. 812. 813, 815, 816,817,
81S, 821, 822, 825, 826, 827, 82t:!, 829, 830, N31, 832, and 833; test pits IP1, IP2, IPS, IP6, IP7, IPS, IP 1 0,
IP11, IP12, and IP19; and hand auger boring HA1. Samples were collected from 0 to 15 feet below ground surface.
-------
Table 1S
SRCPP: Soil Exposure Point Concentrations
Landfill 4/SRCPP ROD
Fort Lewis, Washington
On-Site Paved and Unpaved Soil
imf~~f~11~i~~~1111~1.1
Volatile OrQanic Compounds
Tetrachloroethene
0.08
No Associated Toxicitv Values
Acenaphthylene
Benzo(g,h,Qperylene
Lead
2 - Methylnaphthalene
Phenanthrene
0.20
0.49
10
:,,2':8<
;:::].9",
:0~20
j'~~
0.69
6.1
0.98 0.11
12 0.83
17 1.0
5.3 0.34
8.8 0.74
19 1.3
2.5 0.24
54 1.1
130 5.4
3.3 0.35
110 1.5
240 10
3.2 0.31
12 4.4
0.52 0.25 D
2.5 0.24 D
500 240
2.5 0.20
5.7 0.49
120 12
210 2.8
410 7.9
Semivolatile OrQanic Compounds
Benzo (a) anthracene
Benzo(b)fluoranthene
Benzo(k)fIuoranthene
Benzo (a) pyrene
Chrysene
D ibenzo (a,h) anthracene
Dibenzofuran
Fluoranthene
Indeno(1,2,3-cd)pyrene
Naphthalene
Pyrene
:0,83
1.0
.0.34
:j:1~~,
).0:24
.....)1~1
5.0
0.35
0.73
.1.~0.d
0.30
0.73
1.2
0.23
0.59
.:.:.:""5.4.,.
(q:3!)
0.45
7.9
Metals
Antimony
Arsenic
Beryllium
Cadmium
Manganese
0.31
3.6
0.21 D
0.23 D
220
;;;~~~~! ~
. d
Notes:
Shaded value indicates the lower of the UCL and maximum concentrations.
a) Mean is calculated arithmetically using one-half the method reporting limit (MRL) for nondetects.
b) Maximum concentration is the maximum concentration measured in all samples.
D - Indicates the calculated value is below the MRL due to the number of nondetects.
mg/kg - Milligrams per kilogram.
RME - Reasonable maximum exposure is the lower of the UCL and maximum concentrations.
UCL - Upper confidence limit of the mean calculated using log-normal transformation of the data.
Concentrations were estimated using chemical data from all soil boring. test pit, and hand auger samples.
collected from 0 to 15 feet below ground surface.
Samples were
-------
Table 15
SRCPP: Soil Exposure Point Concentrations
Landfill 4/SRCPP ROD
Fort Lewis, Washington
Fugitive Dust in On-Site Ambient Air
.1!i:!!:i~~r~~f~~~~~~~f#.1i;:illjjiiji!:!:.!;jil!~~r4~~~~~~~~~~~~;~...'i.!.!I!:!:!'
::':':::':R'pJg"'/:':',:' .::::i1e'iri".!':::;:::::':;::'{::::::':::::'@:?RMJ@::.:::::::;::;.@. '.:<:::'HM~an:'::
.:.....'!-(~gim.~j:..:.!!L:i(rrig/m~):'}::'" .}:..;t(rn9irii5':::::;:.::/\'(mg/m s) /
Volatile OrQanic Compounds
Tetrachloroethene I 2.eE-09 2.0E-09 4.5E-09 3.0E-09
Semivolatile OrQanic Compounds
Benzo(a)anthracene 2.1E-08 2.1E-08 1 .1 E -oe 1.1E-oe
Benzo(b)tluoranthene 2.5E-Oe 2.5E-Oe 2.5E-08 2.5E-Oe
Benzo(k)fluoranthene e.5E-09 e.5E-09 9.0E-09 9.0E-09
Benzo(a)pyrene 1.9E -oe 1.9E-Oe 1.6E -08 1 .6E -08
Chrysene 3.3E-oe 3.3E-Oe 2.4E-08 2.4E-08
D ibenzo (a,h) anthracene 6.0E-09 6.0E-09 4.3E-09 4.0E -09
Dibenzofuran 2.eE -oe 2.eE -08 7.eE-09 8.0E-09
Fluoranthene 1 .4E -07 1.3E-07 1 .1 E -07 1.1 E-07
Indeno(1,2.3-cd)pyrene e.eE -09 e.eE-09 9.3E-09 8.5E-09
Naphthalene 3.eE -08 3.eE-oe 7.eE-09 7.5E-09
Pyrene 2.5E-07 2.0E-07 2.eE-07 2.3E -07
Metals
Antimony 7.eE-09 7.eE-09 6.3E-09 6.0E-09
Arsenic 1.1E-07 9.0E-08 1.2E -07 9.3E-Oe
Beryllium 6.3E-09 5.3E-09 6.3E-09 5.3E-09
Cadmium 6.0E-09 5.eE-09 4.eE-09 4.3E-09
Manganese 6.0E-06 5.5E-06 6.eE-06 5.eE-06
Notes:
a) Mean is calculated arithmetically using one-half the method reporting limit (MRL) for nondetects.
mg/m3 - Milligrams per cubic meter.
RME - Reasonable maximum exposure.
-------
Table 16
SRCPP: Toxicity Values for Contaminants of Concern
Landfill 4/SRCPP ROD
Fort Lewis, Washington
Carcinogenic Effects
. ',:-:.:.:.:.: ','
:.'.:.::",'.'.
.. . ......
.. . . .. ...............
. . ,.... ....n .n. ..
....:(~w~i1rf~J~II;!\i::;:...
.,'"
.",".', ". ...,",',',
......... ..'...'~~Jg~~~~:::..':.'....
,',",',', ',',,'..','..".'.' .'.",.',,',,',',',.. ',",',.",...",",.
. .:.. ':: ."'::.:::::.::'. ::::: ::::::::. :;.:;:;.;: :;:~ij;~~~~i1~jii~jJ~~~;:~ijji:~;;;;:~;~~i;i~~~;~f~!i!li;~~;:
. TYP~...~f..~~;'f.~[.(..!~ffi:?f'..~~~::.:'.:....,.'::'...:.::..::..;:...j(
;;:::m::i:"!A~~'~t.i~ri'.:i::.:!::.:.ji.'.:.j.
Chernical ..
. . . ... . . . . . . .
.. . ... . . . . . . . . . .
"''','' .-.. .
-,"..... ..... .....
.. ... q' "".."'" . ... n. "... ..
s: .rih~i~tiriri::(S:"~I~l~M6:'ti6W\
Volatile OrQanlc Compounds
ChJr\rofonn
6.1E-03
B.1E-02
T etrac hloroethene
5.1E-02
H
1.BE-03
Semivolatile O!9!!!!ic Comp~und~
Benzo(a)anthracene 7.3E+OO a 6.1E+OO a
Benzo (b)fluoranthene 7.3E+OO a 6.1E+OO a
Benzo(k)fluoranthene 7.3E+OO a 6.1E+OO "
Benzo(a)pyrene 7.3E+OO 6.1E+OO H
Chrysene 7.3E+OO a 6.1 E+OO a
Dibe nzo(a,h) anthracene 7.3E+OO a 6.1E+OO a
Indeno(1,2,3 -cd)wrene 7.3E+00 a 6.1E+00 a
~t~tals
Arsenic 1.75E+00 1.5E+01 I
Beryllium 4.3E+OO B.4E+OO H
Page 1 of 2
,','.'.".
82
Hw
82
82
82
82
82
82
82
82
A
82
01 -Sep-93
Kidney and liver
salivary gland tlmors
Liver
Forestomach and dennal
Skin and lung
Osteosarccrnas and lung
liver
Leukemia and liver
Respiratory tract
Respiratory system
Lung
-------
Table 16
SRCPP: Toxicity Values for Contaminants of Concern
Landfill 4/SRCPP ROD
Fort Lewis, Washington
Noncarcino enic Effects
. . .
Chemical ..
\~~9:E~~ii~~hte and Uncerta.l~tY
Volatile Organic Comp.ounds
Chloroform
Beryllium
Manganese - diet
- water
1 E -02 N/A
3E-04 N/A
5E-03 I N/A
1E-01 I 1.1 E-04
3.3E -02 C N/A
Med. 1,000 1 -- Liver effects
Med. 3 1 -- Dermal and vasculature
effects
Low 100 .1 -- Lung effectsb
Med. 1 1 Med. 300 3 CNS and respiratory effects
-- -- CNS effects
Metals
Arsenic
Notes:
a) Oral and Inhalation slope factor for benzo(a)pyrene used as a proxy value for all carcinogenic polycyclic aromatic hydrocarbons.
b) Critical effects obtained from Klaassen, et aI., 1966. .
S - Source of Information:
I - IRIS (downloaded July 1992)
H - HEAST (1992)
Hw - HEAST (1991) - withdrawn value.
C - Based on USEPA Region 10 memo (USEPA. 1991e).
CL - Confidence level in RfO.
mg/kg-day - Milligrams per kilogram body weight per day.
MF - Modifying factor.
N/A - Factor or dose not available.
RfD - Reference dose.
UF - Uncertainty factor.
This Information was not available for this chemical.
Page2of2
01-Sep-93
-------
Table 17 .
SRCPP: Summary of Estimated Health Risks for
Current and Potential Future Populations
Landfill 4/SRCPP ROO
Fort Lewis. Washington
Scenario 1:
Current Militarv Residents
Ingestion - groundwater
Inhalation - VOCs via showering
- VOCs via household use
Total Scenario: .
Scenario 2:
Current SRCPP Facility Emplovees
Ingestion - soil
Inhalation - dust
Ingestion - groundwater
Total Scenario:. .
Scenario S:
Future On-Site Residents
Ingestion - soil
Child
Adult
Inhalation - dust
Inhalation - indoor air (soil volatiles) .
Ingestion - groundwater
Inhalation - VOCs via showering
- VOCs via household use
Total Scenario (Adults): .
Scenario 4: .
Future Adiacent Residents
Ingestion - groundwater
Inhalation - VOCs via showering
- VOCs via household use
Total Scenario: .
. ..... . . .
. ... n.... .. .. ..... . .
EX~.'Ufetffi1~':C;h~t}Ri~. :(:..::::::\.chronidHai.ardlrid~~::.::::.;:\:
. .. ..
.:::::m:Av~g::::::.::.:
.:EX~~~~:~::
. n.. . ..
,............ .... ..".... .....
:.::::::.:..:::.Av.~i.~ge::::.:;..;.
t:::::::~~~f:~.::(
1 x 10-5 3 x 10-6 4.5E-01 2.4E-01
4 x 10-7 1 x 10-8 N/C N/C
4 x 10-6 8 x 10-7 N/C N/C
2 x 10-5 4 x 10-6 4.5E-01 2.4E-01
3 x 10-6 5 x 10-7 5.0E-03 1.9E -03
5 x 10-7 1 x 10-7 3.7E-02 2.4E-02
2 X 10-5 3 X 10-6 1.6E-01 7.8E-02
2 x 10-5 4 x 10-6 2.0E-01 1.0E-01
7 x 10-5 6 x 10-6 N/A N/A
N/A N/A 2.6E-01 8.4E-02
N/A N/A 2.8E-02 9.0E-03
2X10-7 5 x 10-8 4.4E-02 a.OE-Q3
2 x 10-6 4 x 10-7 N/C N/C
1 x 10-3 6 X 10-4 1.0E+01 2.7E+OO
1 x 10-6 1 x 10-7 N/C N/C
1 x 10-5 7 x 10-7 N/C N/C
1 x 10-3 6 x 10-4 1.0E+01 2.7E+OO
1 x 10-3 6 X 10-5 1.0E+01 2.6E+OO
1 x 10-6 1 X 10-7 N/C N/C
1 x 10-5 7 x 10-7 N/C N/C
1 x 10-3 6 x 10-5 1.0E+01 2.6E+OO
Notes:
RME - Reasonable Maximum Exposure.
VOCs - Volatile organic compounds.
N/C - Risk estimates or hazard indices were not calculated for this pathway.
N/A - Risk estimates or hazard indices were not applicable for this pathway. .
a) Total scenario estimates calculated by summing exposure pathways and excluding inhalation of VOCs via
showering (Scenarios 1, 2, and 4). There are no differences in total scenario risk estimates using either exposure
pathway for inhalation of groundwaterVOCs. except that Scenario 1 risk estimates differ by 1 x 10-5 and 1 x 10-6
-------
e.
Uncenaintv
Carcinogenic and non~arcinogenic health risks were estimated in the RA for the SRCPP using
various assumptions. Therefore, the RA results presented in Table 17 contain an inherent
amount of uncenainty. The extent to which health risks can be characterized is primarily
dependent upon the accuracy with which a chemical's toxicity can be estimated, and the
accuracy of the exposure estimates.
Examples of the uncenainty in the exposure and the methodology are as follows:
VOC chemical concentrations at Sullivan Well were not available. Therefore,
concentrations from monitoring wells between the SRCPP and Sullivan Well
were used as substitutes. Risk estimates for ingestion of Sullivan Well
groundwater in all current scenarios may be overestimated.
Total metal concentrations were used to characterize future risk due to
ingestion of on-site groundwater. Most of the risk calculated is likely due
either to background metal concentrations or to particulate matter in the well
that would probably not be available in a drinking water supply well.
Equilibrium partitioning was used to estimate P AH concentrations in
groundwater in a future use scenario where the pavement is removed and
increased rainwater infiltration and leaching occur. Based on limited existing
data from unpaved areas, it appears the estimated concentrations are at least
three orders of magnitude higher than current concentrations. This results in a
considerable overestimation of the future risk due to ingestion of carcinogenic
PAHs in groundwater. However, the risk due to ingestion of these potentially
leached chemicals adds only 5 percent to the total cancer risk for ingestion of
groundwater.
In addition to these sources of uncertainty, the chemical analytical data base has limitations in
such areas as sample locations and sample representativeness. These uncertainties are present
in every baseline RA.
2.
Ecolo2ical Risk Assessment
An ecological RA was conducted to evaluate the potential adverse impacts to plants and
animals resulting from exposure to contamination associated with the SRCPP. The results of
the ecological RA were intended to support management decisions on whether remedial action
is required for environmental protection.
The approach used in the RA is consistent with EP A guidance for evaluating ecological risk.
The basic steps were identification of COCs, assessment of potential exposure pathways, and
characterization of threats to exposed biota.
-------
a.
Exposure Assessment
1.
Exposed Populations
Potential receptors were identified as those plant and animal species likely to be exposed to
chemicals in Sequalitchew Lake sediments and surface water, soil in the wastewater lagoon,
surface soil at the SRCPP. However, the SRCPP provides poor wildlife habitat, thus making
the likelihood of significant exposures and toxic effects remote.
No threatened or endangered plant species are known to exist in the SRCPP study area. No
threatened or endangered animal species are known to nest within the SRCPP study area; the
bald eagle (threatened) and peregrine falcon (endangered) have been observed flying over the
area. No critical habitats were identified within the study area.
11.
Exposure Pathways
The .exposure assessment identified potential exposure pathways from the chemical source to
the affected media, exposure points, and potential receptors. Potential exposure pathways
include surface water and sediments in Sequalitchew Lake and soil in the wastewater lagoon.
The exposure to lake water and sediments is potentially more serious than soil exposure
because of the number of potential receptors and the potential intensity of the exposure.
Groundwater was considered an unlikely pathway because the water table is normally fifteen
to twenty feet bgs; consequently ecological receptors cannot come into direct contact with it.
b.
Risk Characterization
Qualitative ecological RA results indicated no likely adverse affects as a result of exposure to
SRCPP-derived contaminants. Similarly, quantitative ecological RA results indicated no
likely adverse affects resulting from SRCPP contaminants.
c.
Uncertainty
Assumptions that tend to overestimate potential exposure include the following:
Wildlife species are continuously exposed to maximum contaminant
concentrations.
Contaminants are 100 percent bioavailable.
Maximum detected groundwater contaminant concentrations discharge to
Sequalitchew Lake without attenuation, dilution, or precipitation.
Published toxicity data for specific fish of wildlife species are applicable to all
other fish or wildlife species.
-------
F.
REMEDIAL ACTION OBJECTIVES
Remedial action is required at the SRCPP to protect human health and the environment under
potential future land use conditions. Action is required because:
~
Soils beneath the site are contaminated with carcinogenic P AHs at levels exceeding
State regulatory requirements.
~
Carcinogenic PAHs in soil have the potential, if site pavements are removed, to
adversely impact groundwater. Predictive modeling indicates risks from impacted
groundwater could exceed MTCA risk goals.
Arsenic, beryllium, and PCE are not included because they were detected at concentrations
that are below regulatory cleanup levels. Chloroform is not included because it is thought to
be present as a drinking water chlorination by-product Manganese is also not included
because it is confined to a localized area and it is expected to rapidly decline due to
implementation of the final remedy, as described in The Selected Remedv section.
Contaminated soil requires action. RAGs were formulated to protect human health and the
environment from potential threats associated with site contaminants. RAGs for the SRCPP
include:
~
Prevent exposure to contaminated soils.
~
Prevent movement of contaminants from soil to groundwater.
~
Prevent exposure to contaminated upper aquifer groundwater beneath the former
SRCPP.
Soil cleanup levels have been established to meet regulatory requirements. MTCA Method B
was used to set the cleanup level for P AHs at 1.0 mg/kg.
G.
DESCRIPTION OF ALTERNATIVES
The remedial alternatives for the SRCPP were divided into two groups: those addressing soil
and those addressing groundwater. The preferred alternative of each group is combined to
form a single cleanup action following the individual evaluations.
Regardless of the alternative selected, portions of the SRCPP will be demolished incident;.! I III
cleanup actions implemented at the site. Demolition costs are not included in alternative
costs, and may include all industrial process lines, tanks, and structures, as well as rem~linin::
plant buildings not currently used for other purposes.
-------
1.
Soil Cleanup Alternatives
Soil Alternative 1: No Action
Under this alternative, which is presented as a baseline for comparison against other
alternatives, no action would be taken. This alternative assumes continued light industrial site
use. The cleanup of soil contamination would only occur through natural processes. Because
of the variety of contaminants in the soil, it is estimated that these natural processes would
require more than 50 years to achieve State environmental standards. Present worth costs are
estimated at $0.
Soil Alternative 2: Institutional Controls
This alternative includes institutional controls such as access restrictions and land use
restrictions. This alternative assumes continued light industrial site use. It is estimated that
natural processes would require more than 50 years to achieve State environmental standards.
Present worth costs are estimated at $29,000.
Soil Alternative 3: Asphalt Cap
This alternative includes institutional controls and paving uncovered operational areas with
asphalt. This alternative assumes continued light industrial site use. The asphalt cap would
protect site users against contact with contaminated soils or dust. It would also inhibit
leaching of carcinogenic P AHs from soil to groundwater.
Pavement would be placed in currently unpaved areas within the former SRCPP process area:
approximately 5 acres would require paving. All vegetation would be removed and the soil
would be sterilized. Site soils would be graded and unsuitable areas'removed and replaced.
CarcinogenicPAHs in soil would naturally degrade over time due to biological processes.
However, the time frame to meet cleanup levels would likely be greater than 50 years.
Present worth costs are estimated at $357,000. .
Soil Alternative 4: Single Barrier Cover
This alternative is similar to Alternative 3, with the exception that a single barrier cover ;Jnd
soil layers would be installed over the operations area in place of the asphalt layer. Th i"
alternative would allow for recreational use of the SRCPP site. The cover would inhibir
contaminates from being leached into the groundwater. Institutional controls would be u ",-,d
to insure maintenance of the cover and to prevent exposure to soil contaminants.
Carcinogenic PAHs in soil would naturally degrade over time due to biological pro.:c,,","
However, the time frame to meet cleanup levels would likely be greater than 50 year~.
Present worth costs are estimated at $ 1.839.000.00.
-------
Soil Alternative 5: Soil Excavation and Treatment
Contaminated soil would be excavated from the former process area and tank farm, and
treated by either soil washing or thermal destruction technologies. The approximate extent of
soil excavation is shown on Figure 14. A treatability study would determine which
technology is chosen. Following treatment, the site would be backfilled with the treated soil
and revegetated. This alternative, which would allow for unrestricted use, would protect
human health and the environment by removing and treating contaminated soil. thus
protecting groundwater by removing potentially leachable contaminants from the soil.
Conceptual design estimates indicate a range of approximately 30,000-80,000 cubic yards of
contaminated soil would require removal and treatment.
Soil washing would extract contaminants from the soil matrix using a washing solution and
spray or mixing equipment. Thermal destruction of soil contaminants would likely employ
low temperature thermal desorption. Treatment residuals would be disposed of at an EP A-
approved off-site disposal or recycling facility. The time required to achieve State
environmental standards is estimated to be less than 2 years. Assuming a soil washing
treatment technology is chosen, present worth costs are estimated at $4,776,000.
2.
Groundwater Cleanup Alternatives
Groundwater Alternative 1: No Action
The no action alternative is presented as a baseline for comparison to other groundwater
alternatives. Under this alternative, no action would be taken to reduce groundwater
contamination. A monitoring program would be implemented to monitor groundwater
contamination. It is estimated that contaminant concentrations would decrease to acceptable
levels due to natural processes in approximately 50 years. Present worth costs are estimated
at $80,000.
Groundwater Alternative 2: Institutional Controls
With this alternative, groundwater monitoring would continue and. institutional controls would
be implemented. Institutional controls may include access restrictions and/or further land use
restrictions, in addition to existing Fort Lewis groundwater well installation restrictions. It is
estimated that contaminant concentrations would decrease to acceptable levels due to natural
processes in approximately 50 years. Present worth costs are estimated at $81,000.
Groundwater Alternative 3: Groundwater Extraction and Treatment
This alternative includes groundwater monitorinf!. institutional controls, and groundwater
, ..... II.. "-
extraction and treatment. Eight extraction wells would be installed and the extracted
groundwater would be treated to remove contaminants. Contaminated groundwater would be
treated using a carbon filter unit. Treatment residuals would be disposed of at an off-site
-------
-
- -
- - -
-
,...
fI--
I' " - -..
.--", " -.._-
:", ' -
, ".' - 7 -:- -:- ~ , - . - ~---:' . - - - -
II ~~-::..-- ;'~-
,,, ---.- -"-0.--,-".'
"
\\
I,
"
"
I
'I
I,
, ,
" \
\
I ,
I
..,----
\ , - - - _. -
',, ----
I' --- -
,I - - -
I' -
I' - -
11
- --
- -
-------
"
'I
"
,
DRAWN
KM
cr
\~RCPP' A" < :: ~s""'nFo" 200
Co t' pproxlmat E '
n aminated Solf xtent 01
Landfill 4/SRCP Removal
APPROVED Fort Lewis, was~ ROD
HLL - nglon
DATE
9 ApI. 93
-
_. .
-
Nole' 51' '
, lading incl'
Icales '
Ihought t 5110 area
a potontial!
conlamlnaled "y contain
It ' 5011 P
115 area willlikel' ortions 01
y be clean,
;!
a>
..
on
/ /'
A II / /
pp ed Geole
Geotechnical E ~hnology Inc
Geology & II ngll1eering .
ydrogeolog
y ,
fiGURE
14
REVISED
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EPA-approved disposal or recycling facility. Treated water would be discharged either to
Sequalitchew Lake or groundwater recharge trenches, dependent on cost and impl~mentability~
State drinking water standards would be achieved in 10 to 20 years. Present wonh costs are
estimated at $9,400,000.
H.
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
In this section, each soil alternative is compared against each other soil alternative, and each
groundwater alternative is compared against each other groundwater alternative. This
comparison uses the nine evaluation criteria presented in the LF4 Summary of Comparative
Analvsis of Alternatives section.
1.
Comoarative Analvsis of Soil Alternatives
a.
Threshold Criteria
1.
Overall Protection of Human Health and the Environment
Alternatives I and 2 would not provide protection from potential contaminants nor prevent
contaminant migration within a reasonable time frame. It is not reasonable to encumber. the
use of this property for this time frame, given adjacent industrial and recreational uses and the
potential for future industrial or recreational development. Thus alternatives I and 2 are not
protective of human health and the environment.
Alternatives 3 and 4 prevent physical contact with soil contaminants and reduce the potential
for these contaminants to affect groundwater, but do not reduce or remove the contaminants
from the soil.
Alternative 5 offers the most protection to human health and the environment. It reduces
contaminant levels, prevents future degradation of groundwater quality, and would be most
protective of future site and groundwater use.
2.
Compliance with ARARs
Alternatives 1 and 2 may attain State soil cleanup levels through natural processes. However.
these levels would not be achieved within a reasonable time frame and in the interim, soil
contaminant levels would continue to exceed State soil standards.
Alternatives 3, 4, and 5 would achieve compliance with ARARs and would not require
waIvers.
b.
Primary Balancin!! Criteria
Alternatives 1 and :2 do not satisfy the threshold criteria since they do not provide adequate
protection of human health and the environment nor comply with Federal and State
-------
environmental standards within a reasonable time frame. Because these alternatives do not
satisfy threshold criteria, they are not considered further in this analysis as an option for site
remediation. .
3.
Long-Term Effectiveness and Permanence
Alternatives 3 and 4 would require enforcement of existing institutional controls, and routine
inspection and maintenance of cover.
Alternative 5 allows for unrestricted future use.
4.
Reduction in Toxicity, Mobility, and Volume through Treatment
Alternatives 3 and 4 control direct exposure to contaminants, but do not treat contaminated
soil.
Alternative 5 offers the greatest reduction in toxicity, mobility, and volume by removing and
treating the soil contaminants.
5.
Short-Term Effectiveness
None of the alternatives would likely pose risks to human health and the environment during
construction and operation. Workers and nearby communities would be protected during site
activities by engineering and safety controls.
Alternative 5 may require additional controls to protect workers from dust generated during
construction and would achieve protection in the shortest time frame (within 2 years).
6.
Implementability
All alternatives use readily available services and materials. Because of the variety of
contaminants, Alternative 5 requires treatability studies to determine the appropriate treatment
technology.
7.
Cost
Alternative 3, which includes placement of additional asphalt cover and long-term
maintenance of the site, is estimated to cost $357,000. Alternative 4, including design and
construction of a single barrier cover and associated long-term maintenance, is estimated to
cost $1,839,000.
Alternative 5, with an estimated cost of $4,776.000, is the most expensive.
-------
c.
Modifying Criteria
8.
State Acceptance
The State concurs concurs with the final remedial alternative described in this ROD.
been involved throughout the process and its comments have been considered and
incorporated throughout.
It has
9.
Community Acceptance
Comments received during the public meeting and public comment period were considered
during selection of the final remedial alternative. Community response to the remedial
alternatives is presented in the Responsiveness Summary, which addresses e,omments received
during the public comment period.
2.
Comparative Analvsis of Groundwater Alternatives
a.
Threshold Criteria
1.
Overall Protection of Human Health and the Environment
Alternative 1 would not provide protection from potential contaminants nor prevent
contaminant migration within a reasonable time frame. It is not reasonable to encumber the
use of this property for this time frame, given adjacent industrial and recreational uses and the
potential for future industrial or recreational development. Thus, Alternative 1 is not
protective of human health and the environment.
Alternative 2 would provide adequate protection only in conjunction with Soil Alternatives 3,
4, or 5. These combinations would manage soil contaminants so that they do not impact
groundwater.
Alternative 3 would provide adequate protection by extracting and treating contaminated
groundwater, assuming that soil contaminants leached into the groundwater.
2.
Compliance with ARARs
Alternative 1 may attain State groundwater cleanup levels through natural processes.
However, these levels would not be achieved within a reasonable time frame and in the
interim, groundwater contaminant levels would continue to exceed State groundwater
standards.
Alternatives 2 and 3 meet ARARs and do not require waiv~rs.
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b.
Primary Balancing Criteria
Alternative 1 does not satisfy the threshold criteria since it does not provide adequate
protection of human health and the environment nor comply with environmental standards
within a reasonable time frame. Because this alternative does not satisfy threshold criteria, it
is not considered further in this analysis as an option for site remediation.
3.
Long-Term Effectiveness and Permanence
Alternative 2, in conjunction with Soil Alternative 3, 4, or 5, would control the suspected
source of groundwater contamination, thus providing long term protection. Although
alternative 3 offers protection of groundwater by extracting and treating contaminated
groundwater, it does not address the suspected source of groundwater contamination.
4.
Reduction of Toxicity, Mobility, and Volume through Treatment
Alternative 2, when combined with Soil Alternatives 3, 4, or 5, would reduce the toxicity,
mobility, and volume of contaminated groundwater by controlling or removing the potential
source of groundwater contamination.
Alternative 3 would reduce the toxicity, mobility, and volume of contaminated groundwater,
particularly if soil contaminants are allowed to leach into groundwater.
5.
Short-Term Effectiveness
None of the alternatives would likely pose risks to human health and the environment during
construction and operation. Workers and nearby communities would be protected during site
activities by engineering and safety controls.
6.
Implementability
Alternative 2 could be easily implemented.
Alternative 3 could be implemented using existing technologies and available services and
materials, but would require substantial engineering and design.
7.
Cost
Alternative 2 is substantially less expensive than alternative 3.
c.
Modifving Criteria
8.
State Acceptance
-------
The State concurs with the final remedial alternative described in this ROD. It has been
involved throughout the process and its comments have been considered and incorporated
throughout.
9..
Community Acceptance
Comments received during the public meeting and public comment period were considered
during selection of the final remedial alternative. Community response to the remedial
alternatives is presented in the Responsiveness Summary, which addresses comments received
during the public comment period.
I.
THE SELECTED REMEDY
The selected remedy combines Soil Alternative 5 (excavation and treatment) and Groundwater
Alternative 2 (institutional controls). This combined alternative is selected because it protectS
the groundwater from future contamination by excavating and treating the suspected source of
groundwater contamination. Excavated soils would be treated to the State soil cleanup
standards.
The groundwater monitoring program and periodic reviews would evaluate the selected
remedy's effectiveness. These reviews would determine what additional actions, if any,
would be appropriate.
1.
Maior Components of the Selected Remedv
Major components of the selected remedy include:
~
Excavating and treating contaminated soils. Soils will be treated using either soil
washing or thermal destruction to meet cleanup levels.
~
Monitoring upper aquifer groundwater beneath and adjacent to the site to determine
the effectiveness of soil treatment.
~
Maintaining institutional controls restricting access to and development at the site as
long as hazardous substances remain onsite at levels that preclude unrestricted use.
The goal of this remedial action is to restOre groundwater to its beneficial use, which is, at
~ ~
this site, a potential drinking water aquifer. Based on information .obtained during the RI and
on a careful analysis of all remedial alternatives, the Army, EP A, and Ecology believe that
the selected remedy would be able to achieve this goal.
Remediation Goals
..,
.....
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Soil cleanup levels have been established to meet the State ARARs which will result in a
cumulative risk not to exceed 1 x 10-5. MTCA Method B was used to set the SRCPP soil
cleanup level for total carcinogenic P AHs at 1.0 mglkg.
The:; following seven carcinogenic P AHs were identified as soil contaminants during the RI:
benzo(a)anthracene; benzo(b)fluoranthene; benzo(k)fluoranthene; benzo(a)pyrene; chrysene;
dibenzo(a,h)anthracene; and ideno( 1 ,2,3-cd)pyrene.
The approximate extent for the point of compliance for soil remediation is throughout the site
(as shown by the shaded area on Figure 14) from the ground surface extending venically to
the uppermost level of the saturated zone. The point of compliance for groundwater, and the
specific components of the compliance monitoring program for soil and groundwater will be
developed by the Army, EPA, and Ecology during remedial design as part of the Remedial
Action Management Plan.
The monitoring program for groundwater may include only PAHs. manganese. and field
parameters. PAHs and manganese will be evaluated against their corresponding groundwater
cleanup standards. which are 0.1 ~g/L and 80 ~g!L. respectively. If the monitoring indicates
that P AHs or manganese exceed action levels. the need for remediation will be reevaluated.
This reevaluation may include supplemental sampling or additional source characterization.
00 a periodic basis. the following groundwater indicator parameters may also be sampled and
analyzed for: calcium. magnesium. potassium. sodium. bicarbonate. chloride, sulfate. nitrate.
oxygen. nitrogen. silica, and iron.
In addition, because of the potential for process leaks or surface spills at the tank farm. total
petroleum hydrocarbons will also be analyzed for in the groundwater in proximity to the tank
farm. This contaminant will be evaluated against its State of Washington groundwater
cleanup standard of 1000 pg/L.
J.
STATUTORY DETERMINATIONS
Under CERCLA Section 121. selected remedies must be protective of human health and the
environment. comply with or provide basis for waiver of ARARs, be cost effective. and
utilize permanent solutions and alternative creatment technologies or resource recovery
technologies to the maximum extent practical. CERCLA also stipulates a preference for those
remedies which. as a principal element. significantly and permanently reduce the toxicity.
mobility. and volume of hazardous wastes.
1.
Protection of Human Health and the Environment
The selected remedy protects human health and the environment through excavation and
treatment of contaminated soils, institutional controls. and groundwater monitoring to insure
remedy effectiveness.
-------
Residual risks at the cleanup levels are 7 x 10./1. Thjs is below the MTCA site-wide risk goal
of 1 x 10".5 and is also within the CERCLA acceptable range of 1 x 1O~ to 1 x 1O~.
2.
Attainment of ARARs
The selected remedy vf soil excavation and treaunent will comply with all ARARs of State
and Federal regulations.
Action-Specific
Resource Conservation and Recovery Act (40 CFR 262). Establishes standards for
ge.ne.rators of hazardous wa$:te$ for the troating. stornge. nnd shipping of wastes.
Applicable to the storage, packaging, labeling. and manifesting of the waste residuals
off.sire for treatment.
Hazardous Materials TraMportation Act (49 use 1801-1813 and 49 CFR Parts 171
and 172). Applicable for lnmsporUiUon of potc:mla11y hazardous materials, including
samples and wastes.
Dangerous Waste Regulations (Chapter 173-303 WAC). Applicable for onsite
treatment. storage. or disposal of dangerous wa.c;te or hazardous waste generated during
the remedial action.
Minimum Standards for Construction and Maintenance of Wells (Chapter 173-160
WAC, as modified by Engrossed Substitute House Bill 1 X(6). Relevant and
appropriate regulations for the location. design. construction, and abandonment of
water supply ann r~~nnrc~ prntet.~t10n we.lIs.
Ambient concentrations of tmdc air contaminants in the Puget Sound region are
regulated by PSAPCA pursuant to the State of Washington Clenn Air Act (Chapter
70.94 RCW) and Implementation of Regulations for Air Contaminant Sources (Chapter
173-403 WAC). The BAcr wi11 be reQuired for sources of toxic air contaminants to
minimize emissions. The ambient impact of emissions of toxic air contaminams from
new sources will be evaluated against ASILs adopted by PSAPCA.
Chemical-Specific
MTCA (Chapter 173.340 WAC). Method B risk-based cleanup levels are applicah!r'
for establishing soil and groundwater cleanup levc:l:i.
Resource Conse.rvation and Recovery Act. Subtitle C (40 CFR 261). Applicabl~ In
identifying if soil treatment residuals are considered a hazardous waste for purpose, l1!
transporting them off-site for treatment.
-------
Location-Specific
No location-specific ARARs.
Other Criteria, Advisories, or Guidance to be Considered Materials
EPA OSWER Direcliv~ 9834.11. Revised Procedures for PlanninS! and lmolementing
Offsite Re~non~~ Actions, November 13. 19&7. This directive provides pnx;cdures for
offsite disposal of CERCLA wastes.
3.
Cost F:fTect.ivene..~~
The sele<.:ted remedy (soil alternative 5 and groundwater alternative 1) is cost-effective
because it has been determined to provide overall effectiveness proportionate to its cost and
duration with respC(;t to both soil and groundwater.
4.
Utilization of Permanent Solutions and Alternative Treatment Technoloeies to the
Maximum Extent Practicable
The AImy, EPA, and Ecology have determined the sele~lcd remedy represents the maximum
extent to which permanent solutions and treatment technologies can be used in a cost-
effective manner for the SRCPP. The principa1 threat.. asso<.:iated with the site ilre perm",ncnt-
ly reducen throll2h fTf".:ltmp.nt without tr~nsferrins the rick!1 tn other mcdi~. TI\C ~c1c\"lc;U
remedy provides the best balance of long-tenn effectivene~~ ann permanence. reduction in
toxidty, mobility, and volume through treatment. short-term effectiveness. implementability,
and cost
5.
Preference for Treatment as a Principal Element
The selected remedy satisfies the statutory preference for treatment as principal element by
actively treating contaminated soils.
K.
DOCUMENTATION OF SIGNIFICANT CHANGI<:S
The propo~ed plan for the SRCPP was released for public comment 011 May 31. 199~. Public
comments on the proposed plan were evaluated at the end of the comment period, and it 'W3S
determined that no significant changes to the proposed plan were necessary.
-------
RESPONSIVENESS SUMMARY
The public comment period on the Proposed Plan for both LF4 and the SRCPP was held from
May 31 to June 30, 1993. Three sets of written comments were received and are included in
Appendix A.
A public meeting was held on June 15,1993 to explain the Proposed Plan and solicit public
comments. Ten members of the public attended the meeting. Two members of the public
participated in a discussion following the presentation. Both offered suppon for the selected
remedies. The transcript of the public meeting is available in the Administrative Record.
This summary is a response to items raised in the written comments.
1.
Comment:
A letter was received expressing suppon for the selected remedies for each site.
Response:
The proposed remedies are believed to be the best available compromise to address the
hazards posed by the sites.
2.
Comment:
A letter was received expressing no opinion regarding LF4, but did express the
opinion that no remedial action be undertaken at the SRCPP. '
Response:
CERCLA requires the consideration of future site use in determining the selected
remedy. It was determined as part of the investigative process and the baseline risk
assessment that an unacceptable future risk exists due to ingestion of, inhalation of
fugitive dust from, and direct contact with contaminated soil at the SRCPP. In
addition, contaminated soil represents a likely source of potential groundwater
contamination should site pavements be removed.
Therefore, the final remedial action is. warranted because it will be protective of
human health and the environment, and will restore the site for unrestricted future use
within a reasonable timeframe.
..,
_1.
Comment:
A letter was received expressing no opinion regarding the SRCPP but did comment on
-------
the prefelTed alternative for LF4. This party indicated that the prefelTed alternative
should include capping of the landfill.
Response:
Although capping was considered, it was not included in the preferred allernative
because:
~
Contaminant distribution patterns in groundwater and soil gas indicate principal
sources of groundwater contamination are located oUlc;ide the landfill.
~
Aerial photographs indicate historical disposal activities outside the landfill
boundaries.
For these reasons, it is believed that capping the landfill would not decrease
groundwater contamination or provide substantially more protection of human health
and the environment. Furthermore, capping the landfill is not likely to provide
sufficient incremental increase in protectiveness relative to the increase in cost.
A 5-year review wil.1 be conducted: remedy effectiveness will be evaluated at this
time. Should evaluation indicate the remedy is not providing adequate protection of
human health and the environment, other potential remedial actions. including
excavation and capping, will be evaluated.
-------
List or Acronyms and Abbreviations
ARARs - applicable or relevant and appropriate requirements
Army - U.S. Anny
ASIL(s) - Acceptable Source Impact Level(s)
BACT - Best Available Control Technology
bgs - below ground surface
CERCLA - Comprehensive Response, Compensation, and Liability Act of 19XO
COC(s) - contaminant(s) of concern
CRP - community relations plan
DCE - dichloroethene
Ecology - Washington State Department of Ecology
EPA - U.S. Environmental Protection Agency
FFA - Federal Facility Agreement
Fort - Fort Lewis Military Reservation
FS - feasibility study
ftlday - feet pcr day
ftlyr I. fcct pcr year
HI - Hazard Index
LF4 - Landfill 4
MCL(s) - maximum contaminant level(s)
rng/kg - milligrams per kilogram
mg/m' - milligrams per cubic meter
rvfSL - Mcan Sea Level
MTCA - Washington State Model Toxics Control Act
NCP - National Oil and Hazardous .Substances Pollution Contingency Plan
PAtf(s) - polycyclic aromatic hydrocarbon(s)
PCE - tetrachloroethene
PNL - Battelle's Pacific Northwest Laboratory
PQL - practical quantitation limit
PSAPCA - Puget Sound Air Pollution Control Agency
RA - risk assessment
RAOs - rcmcdial action objectives
RfD(s) - reference dose(s)
RI - rcmcdial investigation
RIIFS - rcmcdial investigation/feasibility study
ROD - Rccord of Decision
S F(s) - slopc factor(s)
SRCPP - Solvcnt Refined Coal Pilot Plant
SVOC(s) - sCl11ivolatile organic compouncl(s)
TCE - trichloroethcne
TP - Tcst Pit
pg/L - rnicro!!rams per liter
-------
List of Acronyms and Abbreviations (continued)
pg/m) - micrograms per cubic meter
VC - vinyl chloride
YES - vapor extraction system
VOC(s) - volatile organic compound(s)
-------
IIQ I Corps and .Fort Lewis
ATTN: 1\FZH-DEQ (Ms. Wofford)
Fort Lewis.- JlA 98433-5000
June 7, 1993
---...;:;~
Office of Administration
Mayor Janda Volkmer
\.
Dear Ms. Wofford,
I have read the informational report concerning the proposed plan
for cleaning the sites identified as Landfill 4 and the Coal
Pilot Plant. While there is considerable distance separating
the Town of Steilacoom and these sites the environmental
contamination is still of great concern to the Town.
In seeking the preferred alternative for the cleaning of tllese
sites, tile Town of Steilacoom recognizes the importance that time
and money play in the making of these decisions. However, the
Town strongly recommends that the method which will remove
contamif\ates and/or cleans the soils be selected as the preferred
alternative. The Town of Steilacoom obtains all of its water
from wells located within our community; however, Fort Lewis and
the Town of Steilacoom share the same aquifer. Environmental
contamination on Fort Lewis has the potential of impacting our
water supply:.
The protection of safe and clean drinking water for our community
is of importance to the Town of Steilacoom. For this reason the
Town would recommend a method which would best protect the water
supply for both Fort Lewis and the Town of Steilacoom. The Town
of Steilacoom supports the preferred alternatives as recommended
in your May 1993 report.
Sincerely,
~ ?d
./ ----- ~
C::::=S even Fis6
Planner
Pl10ne 501-1900
Ff\X 582.3-163
1715 L"'ayclle Slcil;tcoorn. Wf\ 90300
'.
-------
~.
15 j une 93
...'
,IIQ I.Corps and Ft. Lewis
Fort Lewis, WA 98433-5000
Sir:
11m delighted to comment on the proposed cleanup of
the site of the Coal Pilot Plant at Ft.Lewis.
-.
I just returned from ten days spent In the coal region
of Pennsylvania, namely in Coal and Zerbe Townships.
I'd guess the so-called "Problems" at Ft.Lewis are
infinitesimal compared with the scope present in the two
townships mentioned.
Yet, without any outside aid, nature has reclaimed the
affected area, and the White Poplar and Red and River
Birch are flourishing.
I fervently hope no clean up be undertaken. Unless, of
course,
the treasury is overflowing and the surplus must be
spent.
A-2
it
-------
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-'-,': fJ.;..w5. fv-; Io~ ~ -1-- a.W\ V~(J../ / i .
_...._,~ ,Uv'\ ~~ .., ecbod o{;VV so" f tL1~ .
-- ... ~'Y/JIM'..LwcJ..--L,/ i~,- B-'~ G~to ( L
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"
- -. . - . .
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p.
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Ground water too precious not to protect
face- The U.s. EDVU"OI1menUl ProLeC'tioa Agm-
ry w found Il1at CWlmaoe c!Iem1a1s I1ave
cooummated rougbJy :0 pert'e!lt of Ule C'OUD-
try's dr.nl.U1g w a tU aqwfen.
In ~nf Jenn ;aloae, more thaa 5.000 domes-
tic: we.lls and close to :00 public water-scpply
wel.l.s I1.ave been CODtamJlU~ by polluted
ground water.
New Je~y, ;along with Massachusetts., Ftori-
cia aad otber irldumuJ states, b.u esublished
protected zooes SIllTOunding dri.nki.Dg water
wellhe.ads or soil formatiocs where rnntall
By Tom A/unoale
It's ~ LO !ind a loaJ-gover-...:neot offiC1;al
w:)o d be UnUed to le.1I':1 Il1at lIIe !ederu Su-
per.und ;Jro~ LS coaung to town to deaa up
toXIc polluuoQ. Th.at m.ues it even more dU-
Cic:ult to fathom wby loaJ governments still
aren't doirlg ail they can to gu.m:I vuJnera ble
ground-water supplies against future Superfund
fWcoes.
Underground aquifers supply tbe drinking wa-
ter for b.a11 the Amerion people. U notb.irlg
else. SupertllIld has demonstrated bow c:ostly it
can be to c1e.aJ1 ap tbose cracial resources once
tbev've been cont.amll1a~
At most tone waste sites. chemicals pose tbe
most serious threats wbee tbey seep downward
toward water tables.. Yet maay states have
barely begun drafting comprehensive ground-
warer management pl.u1s or even locating and
mapping the aqwIers that are at risk of con-
la.mu1auoQ. .
And maay communities still shy away from
man.1giDg bow la.nd is used above irrepla~ble .
ground-water resources. seeps into tbe grollIld to rech.a.rge aquifers.
Across most of tbe country, tbe feeling per- Those progr-anu put the most sensitive areas
sist3 .that "you can just put sometb.irlg do~ ~ off limits to landfilh, Iw:ardou.s waste dumps
bole UI tbe ground aad not pay any pnce for It., . and oUler clearly dangerous facilities. They also
says Michel J. Paque, executive director of tbe require indllS'triaJ plants to inst.all double-walled
Ground Wa~ Protection CAunciL : fuel t.an.b aad backup systems that will at.ch
lDdeed., we ve always lre3~ ground water ~ spilled chemic:W in the event of accident
a c:be.ap aad coavellJeelly UlV1S1ble c:es.spooL Oil- ., .. '..
dnlling operations aad maay irldustri.a.l p1.a..ots . Taking aa~Uler approadl, Iowa ID 1~&7
have beeo injec'tiDg conf:lmin:lnt-laced fluids launched aa \II11ovauve program encouraglDg
inLO the ground through weUs drilled for that farmers to voluntarily cut ~tl on IlSUIg cbem1-
pur.:>ose.. Gasoline and olller starage t.ank3 hak cals that can find thetr way Into aqu1lers.
pe:.-oleum and chemlc.:ili. wluJe fertilizers and Other sl.ate:s ~ve ~a LaggiDg behiad. Tbe
pesncdes from farm1..uJds and goU COUl"Se3 seep A.s.soc1.1uon of Stale and Interstate Water Pollu-
lI1roa gh per.:n e.ab I e so 1l.s. H U1I1aD wastes !1 OWUlg tio a CAn tro I Ad.IIwIi.stn lOrS scgge:sts divertiD g
lb."OUgtI poorly located sepuc t.an.U ~ve been Superfund mooey to' belp nates come up Wltb
COQ~~ the water beae.aUl senurur:1l sub- Ctlmpre.aetmve ground-water policies. Just be-
dJVUlOns.. . .;, fore IUV\.Dg o~. forme" EPA Admu11straLOr
All too often, we've built tbose bomes a.od Wil.li..a.m K. R..e.illy approved gwdeliDes for states
indt::St.-..aJ pLan:..s 1..0 ~ver val1~ .1Dd other pLac- . t.o follow in settlng up comOre!lenSlve ground-
o lraeTe uound water lio clasen to lIIe sur. W.Jter :n.anage.meet programs.
The U.S. Environmental Protection
AgeOOj has found that manmade
chemicals have contaminated
roughly 20 percent of the
country's drinking ,water aquifers,
(
\oJ \--
~ - '-N .\..
.",... .-- .-......
.... -. . -..... ~
... " . .....
. ,
It's DOW clear that ground-water aDd surbce-
water systems are closely related, and Coagress'
should set clear DauonaJ goals 'for proc.ec-..::(
both. preferably 00 a waters.bed-by.wa\.enbed
b.uu.. But pl'Otec'.::Ig ground water neotaally:
comes down to regu1aung LaDd use. aDd local'
larertlments need to take the iDitLauft. ..
. Prodded by state Laws and pot.eDtW fi.a.anciaJ
li.ability, cities and counties around the COIUItry
are now closiDg .down leaking LaDdfllls, bat goy_,
ernments sboaJd aho be steering industrial and:
residential groWth away from 3eDSitive grouDd-,
water systems. . .' . ,
Aastia. TU2S, and cbne 'CountY. Va., have':
imposed comprehensive LaDd-1J3e restric:tioQS: ,
precisely for that purpose. To keep from COD-. :
taminatirlg an aquifer supplying drinkiJlg water '
t.o SpobDe, the fiV~UDty Panhaadle Health:
District irI aortbern Idaho banned septic tanb'
00 lots of less !.ban 5 acres in Kootenai ColUlty.'
and ordered subdivisions to cootain all nmoff
from storm water. That, in effect. Is forcing
development closer to emting se""ge treat-'
.. ment systems serving Coeur d' Alene and other
towns. , ..~. ,.
. '*We ~ot afford DOt to prevent 'contamina-'
tiOD.," contends Kenneth W. Lustig, the district's
eoviroomenUl bealth dinctor, "because we
cannot afford to clean it up"" I . ' :,' ': .'
Yet 3rollIld the country, most loc:.a1 gov~
ment Iuders still don't seem to comprehend the.
connection between regu1.atirlg bow Land Is ased
and protecting water. .' '.,:: .:' I.
. Two decades ago. it look the Cuyahoga River
1.0 Cleve1.a..od C3tdUog fire to persuade Cocgre:ss
to ~ the Clean Water Act to remove polluuon
from Lakes and strums.. Taday's Superfund mc>-
rass is DOt q1Ute that dramatic:. but it should be
all the wanung communities around the ccnmtry
need that It's time to keep tbe same th.in( from
I1.appemng to grcnmd water, . .. .
. Tom ~~ JrTiles lor GovernitJr Jbl~ :.1
%IDe. - .
. , . .. . .~
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