United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
ePA/ROD/R09-84,007
July 1984
Superfund
Record of Decision:
Stringfellow Acid Pits
Site, CA
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TECHNICAL REPORT DATA
(Please read Instructions on (he re~'e1Se before completing)
1. REPORT NO. 12. 3. RECIPIENT'S ACCESSION NO.
EPA/ROD/R09-84/007 /
4. TITLE AND SUBTITLE 5. REPORT DATE
07/17/84 ./' -
SUPERFUND RECORD OF DECISION:
Stringfellow Acid Pits, CA 6. PERFORMING ORGANIZATION CODE
7. AUTHORISI 8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED
U.S. Environmental Protection Agency 1<'in;>l Rnn
401 M Street, S.W. 14. SPONSORING AG"ENCY CODE
Washington, D.C. 20460
800/00
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The Stringfellow Acid Pits site is located in Riverside County, five miles north-
west of the City of Riverside and one mile north of the community of Glen Avon. The
site was operated by the Stringfellow Quarry Company from August 21, 1956 to November
19, 1972 as a hazardous waste disposal facility. Approximately 34 million gallons
of industrial wastes, primarily from metal finishing, electroplating and DOT produc-
tion, were deposited in evaporation ponds on site. The disposal area totals 17
acres.
The selected interim remedial measure includes installation of an on-site pre-
treatment system consisting oflirne precipitation for heavy metals removal and granu-
lar activated carbon treatment for organics removal. Pretreatment will be followed
by discharge to a publicly owned treatment works (POTW) system. Also, additional
interceptor and monitoring wells will be installed to extract contaminated down
gradient ground water.
Key Words: Alternative Technology, Environmental Impacts, Off-site Disposal,
O&M Funding, Cost Estimates
.
17. KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS b.IDENTIFIERS/OPEN ENDED TERMS C. COSA TI Field/Group-
a.
Record of Decision , ~ .',),'
~U n~ ' ~ ....1 . ;.f ;.. i
Stringfellow Acid Pits, CA I("$t , . '., . .".. . ,,/ .. "~
~. .,. I \1''' M, 'jt"! '~"""I~
Contaminated media: gw, soil - p..).....i'~CI'.~'W \1.4 ~
Key contaminants: pesticides, sulfuric
acids, metals, organics . , IP 9 .."
18. DISTRIBUTION STATEMENT 19. SECURITY CLASS ,Tl1isRepon; 21. NO. OF PAGES
~T,",no 48
20, SECURITY CLASS (This page) 22. PRICE
None
EPA Form 2220-1 (Rev. 4-77)
PREVIOUS EOITION IS OBSOLETE
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UNITED 5'"
"ES ENVIRONMENTAL PROTECT lor
WASHINGTON, D.C. 20460
GENCY
OFFICE OF
SOLID WASTE AND EMERGENCY RESPONSE
JUl I 7 I98Ll
MEMORANDUM
FROM:
Authorization to Proceed with Remedial Action for the
Stringfellow Site, California -- Record of Decision
William N. Hedeman, Jr., Direct<~ J.C tkJi;/\'" i
Office of Emergency and Remedial R /6~' . l~~
Lee M. Thomas
Assistant Administrator
SUBJECT:
TO:
The attached Record of Decision is presented for your
authorization of remedial action at the subject site.
We are asking your approval of the interim measure to install
a treatment facility on-site to treat contaminated ground water
from on-site and the mid-canyon area. Treated effluent would be
trucked to a local sewer line drop point for disposal. Effluent
would receive secondary treatment at the publicly-owned treatment
works and then be discharged to the ocean. Sludge from the
pretreatment process would be taken to a RCRA Class I land disposal
facility.
t
I
Funding for design and some elements of construction is
included in the FY 1984 Revised Remedial Accomplishments Plan.
Attachment
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"4(, PRO'~V
UNITED 5- 'T"ES ENVIRONMENTAL PROTECTIO" \GENCY
WASHINGTON, D.C. 20460
J.l f" 19A~
~);;:=I'::- tJ=
;\-# - 0 '.\'4STt: ..:. '..: ":' -= ..'~ ~ -:.. = '".: ." RE.S=-- - ~
MEMORANDUM
SUBJECT: Record of De~io for Approval of Remedial Action at
1)he Stri~g~l ow a~ifornia Site
rAAlM tA..,I
FROM: ~rank Biro Di ctor
Technical ivision
Office of aste Programs Enforcement (WH-527)
TO:
William N. Hedeman, Jr.,' Director
Office of Emergency and Remedial Response (WH-548E)
The Record of Decision for the Stringfellow, California
Site has been reviewed by my staff.
I Concur
x
I Do Not Concur
I Concur With the
Attached Conditions
Date
7 - ''"7 - '!1-
Comments:
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UNITE[,
:A TES ENVIRONMENTAL PROTECT
~ AGENCY
DATE July 13, 1984
SUBJECT: Recommendation for an Interim Offsite
Stringfellow, Glen Avon, California
h . J~lAl~
FROM Jo n Wlse
Deputy Reg al Administrator, Region
Control Measure for
9 (DRA)
TO- Lee Thomas
Assistant Administrator
Office of Solid Waste and Emergency Response (WH-562A)
Based on the Region's review of the May 18, 1984 report
"Fast Track Remedial Investigation/Feasibility Study, String-
fellow Site", and other available information, I recommend that
installation of a pretreatment plant followed by discharge to a
Publicly Owned Treatment Works system be selected as the interim .'
offsite control measure for the Stringfellow site. This alterna-
tive will provide cost-effective management and disposal of
contaminated groundwate~ to protect public health and the envi-
ronment during the three to five year interim period prior to
completion of the full-scale RI/FS and implementation of the
final remedy.
The California Department of Health Services concurs with
this recommendation, and a letter stating their concurrence will
be forwarded to your office within a few days.
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I
Attachments
E PA Form 1320-6 (Rev. 3-76)
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UNITEl
DATEJuly12,1984
fATES ENVIRONMENTAL PROTECl
-~ AGENCY
SUBJECT Record of Decision
Stringfellow, Glen
FROM Hal~eraYdar ian
Director, Toxics ,
Avon, California
Waste Management Division (T-1)
To-John Wise
Deputy Regional Administrator (DRA)
Attached for your review and signature is the cover memo
and documentation for our recommended alternative for an interim
offsite control measure at the Stringfellow site.
Based on the results of the Fast Track Remedial Investiga-
tion/Feasibility Study, the Toxics and Waste Management Division
recommends installation of an onsite pretreatment plant for
removal of heavy metal and organic contaminants, followed by
discharge to a local Publicly Owned Treatment Works (POTW) system.
Sludge from the treatment process will be deposited at a Class I
facility. This alternative will be implemented during the three
to five year interim period prior to completion of the full-scale
RI/FS and implementation of the final remedy.
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I
Of the alternatives evaluated, this alternative is the lowest
cost and provides the greatest protection to public health, welfare
and the environment. This alternative is supported by the community
of Glen Avon and the California Department of Health Services (DOH3
The Santa Ana Watershed Project Authority (SAWPA), a local
POTW, has submitted a proposal to DOHS for implementation of the
recommended alternative. In anticipation of EPA's approval,
DOHS has entered into a preliminary contract with SAWPA for this
purpose. DOHS is aware that EPA may not pay for any expenses
incurred prior to selection of a remedy through the Record of
Decision process.
In addition to the documentation of this
letter of concurrence to be signed by William
actual Record of Decision to be signed by Lee
in this package.
recommendation, a
Hedeman and the
Thomas are included
If you have any questions concerning this packet of materials,
I will be happy to meet with you at your request.
Attachments
E PA Form 1320-6 (Rev, 3.761
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Record of Decision
Remedial Alternative Selection
SITE:
Stringfellow Acid Pits, Glen Avon, California
DOCUMENTS REVIEWED
My decision is based in part on review of the following
documents describing the analysis of cost-effectiveness of
remedial alternatives for the Stringfellow site:
- Stringfellow Site Fast Track Remedial Investigation/
Feasibility Study, CH2M Hill, May 18, 1984
- Summary of Remedial Alternative Selection
- Responsiveness Summary
- Final Draft Stringfellow Summary Report, Ecology and
Environment Inc., May 16, 1984
DESCRIPTION OF SELECTED REMEDY
Installation of an on-site pretreatment system consisting
of lime precipitation for heavy metals removal followed t
J
by granular activated carbon treatment for organics removal.
Pretreatment will be followed by dischaOrge to a publicly
owned treatment works (POTW) system
- Operation requirements include: Chemical and carbon
replacement, monitoring, electricity, labor, transportation
of treated effluent to a POTW sewer drop point and disposal
of contaminated sludge at a Class I facility.
- Installation of additional interceptor and monitoring wells
to extract contaminated groundwater downgradient of the site.
DECLARATIONS
Consistent with the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), and the
National Contingency Plan (40 CFR Part 300), I have determined
that the installation of a pretreatment system at the Stringfellow
site is a cost-effective interim measure and provides adequate
protection of public health, welfare and the environment. The
State of California has been consulted and .grees ~it~ the approved
remedy. In addition, the action will require operation activities
to ensure the continued effectiveness of the remedy. These
activities will be considered part of the approved action and
eligible for Trust Fund monies until implementation of the
remedial action for final site closure. The State will apply
for operation funds on an annual basis.
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I have also determined that.the action being taken is
appropriate when balanced against the availability of Trust
Fund monies for use at other sites. In addition, the off-site
transport. of sludge and pretreated effluent is more cost-effective
than other remedial actions, and is necessary to protect public
health, welfare, or the environment.
The State of California is currently conducting a full-
scale Remedial Investigation/Feasibility Study to identify and
evaluate methods to prevent or manage upstream groundwater and
surface water entering the site, to prevent migration of hazardous
substance off-site, to define aquifer characteristics, the extent
of the contaminant plume, and methods of controlling migration.
A cost-effective remedial action for final site closure will be
developed. If additional remedial actions are determined to be
necessary, a Record of Decision will be prepared for approval of
future remedial actions.
~ I, ~ / ~f
I Da te (
.D ~'\~.~
~ Lee M. Thomas
Assistant Administrator
Office of Solid Waste and Emergency Response
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SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
STRINGFELLOW ACID PITS
Glen Avon, California
SITE LOCATION AND DESCRIPTION
The Stringfellow site is located in Riverside County, approx-
imately five miles northwest of the City of Riverside and one
mile north of the community of Glen Avon. The site is located
at the head of Pyrite Canyon which lies in the southern portion
of the Jurupa Mountains, approximately 4,500 feet north of the
intersection of U.S. Highway 60 and Pyrite Street. The canyon
opens into the town of Glen Avon, south of U.S. Highway 60.
(See Figure 1.)
The watershed area tributary to the disposal site is approxi-
mately 270 acres. Groundwater beneath the site moves in a semi-
confined aquifer bounded by canyon walls to the north, east and
west. Water flows toward the south, exiting the canyon just
north of Highway 60 and then enters the Chino Basin regional
groundwater system which travels toward the southwest. The
Chino Basin system provides a domestic drinking water supply
for approximately 40,000 potentially affected residents. The
groundwater supply is also used for industrial and agricultural
purposes. Surface runoff from the canyon moves southwesterly
from the site and collects in a culvert drop box just north of
Highway 60. Surface runoff then flows under the highway through
Glen Avon in lined and unlined channels, and eventually to the
Santa Ana River, a total distance of approximately 7 miles.
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The site is surrounded by undeveloped land which is primarily
used as range land. An operating quarry is located about a
quarter of a mile downgradient of the site on the western side
of the canyon.
SITE HISTORY
The site was operated by the Stringfellow Quarry Company from
August 21, 1956 to November 19, 1972 as a hazardous waste disposal
facility permitted by the Santa Ana Regional Water Quality Control
Board (RWQCB). Approximately 34 million gallons of industrial
wastes, primarily from metal finishing, electroplating and DDT
production, were deposited in evaporation ponds on the site.
Site operations also included spray evaporation of pond contents
to accelerate volume reduction. The total disposal area was
approximately 17 acres. The site was voluntarily closed in ~972.
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In 1969 and 1978, excessive rainfall caused the disposal ponds
to overflow. The overflows extended south of Highway 60 into
Glen Avon. In 1980 and 1981, the RWQCB implemented an Interim
Abatement Program at the disposal site as the first phase of site
closure. The program included removal of all surface liquids,
partial neutralization and capping of the wastes, installation
of a gravel drain and a network of extraction, interceptor and
monitoring wells onsite and downgradient of the site, diversion
of surface water around the site via gunite channels, and con-
struction of a clay core barrier dam and leachate colecton system
downgradient of the disposal ponds to stop migration of subsurface
leachate.
For a more detailed description of previous response actions
and enforcement activities, please refer to the July 22, 1983
Stringfellow Record of Decision briefing documents. The following..
paragraphs describe the response actions performed since May,
1983. Enforcement activities are discussed in detail in the
Enforcement section.
State-lead Activities
A $2.8 million cooperative agreement was awarded to the State of
California on July 28, 1983, and a $7.1 million Amendment was
awarded on December 28, 1983 for the Stringfellow site. Activities
funded include initial remedial measures (IRM), interim source
control measures, interim offsite control measures, a remedial
investigation/feasibility study (RI/FS) and reimbursement for
Interim Abatement Program activities. .
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Initial remedial measures funded under the cooperative agreement
include erosion control and fencing. Erosion control measures
were completed in November 1983, and a fence will be constructed
around the ~ite in August, 1984.
Interim source control measures include extraction and offsite
disposal of contaminated groundwater. Groundwater is pumped from
extraction facilities and routed to a series of holding tanks.
It is then transfered to trucks for transport to a Class I disposal
site. Since July, 1983, groundwater has been extracted from
three onsite wells (OW-l, OW-2, OW-4) and two downgradient sources
(the french drain and IW-l) in order to intercept the flow of
contaminated groundwater from the disposal area and to prevent
their migration down the canyon. Between July, 1983 and March,
1984, approximately 150,000 gallons of groundwater was extracted
per week.
On March 23, 1984, EPA Headquarters authorized extraction and
disposal of groundwater from two mid-canyon wells (IW-2 and
IW-3). Since that time, a total of approximately 200,000 gallons
per week of groundwater has been extracted from the onsite
and downgradient facilities.
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JRB Associates was selected by the California Department of
Health Services (DOHS) to conduct the RI/FS. The contract was
'signed on March 26, 1984. The study is scheduled to be completed
on October 15, 1985. The RI/FS will recommend a cost-effective
remedy for final site closure.
EPA-lead Activities
To assist the State prior to commencement of the RI/FS and
other cooperative agreement activities, and for the purpose of
enforcement support, EPA has undertaken the following activities
since April, 1983: emergency response actions, monthly sampling
program, electro-magnetic conductivity survey, installation of
new monitoring wells, the Fast Track RI/FS, treatability studies
and pilot tests of the mid-canyon extraction well field. The
Fast Track study is the basis for this Record of Decision. In
addition, EPA has entered into an Interagency Agreement with the
US Army Corps of Engineers (USACE). The USACE will provide
technical assistance during Remedial Design and the full-scale
RI/FS.
- Emergency Response: In May, 1983, contaminated liquid was
discovered surfacing several hundred yards below the barrier
dam. The contaminated liquid mixed with surface water which
is channeled around the site. DOHS authorized construction
of an open pit to collect leachate and pumping of contaminated
liquids to onsite holding tanks. Contaminated liquid was
disposed of offsite together with the extracted groundwater
described previously.
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In May, 1983, DOHS requested EPA assistance for containment
action. Between May and November, 1983, Region 9's Emergency
Response Team with assistance from the USCG Pacific Strike
Team performed the following activities: installation of a
french drain in the seepage area with a sump to collect
liquids and automatically pump liquids to the holding tanks,
improvement of drainage channels consisting of grading,
trenching and paving, installation of an upgradient spring box
and installation of upgradient "pump barrelll sumps to collect
and divert uncontaminated groundwater around the site.
- Monthly Sampling Program: EPA's
ment (E & E), conducted monthly
tion, interception, monitoring,
through September and November,
contractor,
groundwater
and private
1983.
Ecology and Environ-
sampling of extrac-
wells from April
Electro-magnetic Conductivity Survey: In June, 1983, E & E
conducted an electro-magnetic (EM) conductivity survey to
delineate areas of high ionic concentration in groundwater
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which may be related to inorganic contamination. The survey
results indicated that the extent of the groundwater contam-
ination plume may not have been detected by the existing
monitoring wells. E & E recommended the installation of 4
new monitoring wells to confirm the results of the EM survey.
- New Monitoring Wells: During September and October, 1983,
E & E installed 4 monitoring wells in the lower Pyrite Canyon
area based on the EM survey.
Fast Track RI/FS: The State requested that an EPA-lead Fast-
Track RI/FS be conducted to identify and "evaluate alternatives
to current groundwater extraction and offsite disposal opera-
tions. Originally, this activity was included as Tasks IX
and X in the full-scale RI/FS funded under the cooperative
agreement. The selected alternative, or interim measure,
would be implemented during the 3 - 5 year period prior to
completion of the full-scale RI/FS and implementation of the
final remedy. This activity, conducted by CH2M Hill, was
intiated in September, 1983. The final report, issued on May
18, 1984, is the basis of this Record of Decision.
- Treatability Studies: Since June 4, 1984, CH2M Hill has
performed laboratory characterization and treatability testing
on Stringfellow water to verify the capability of the pretreat-
ment system recommended in the Fast Track report to meet .
pretreatment objectives, and to confirm operating cost estimates.
- Pilot Pumping Test: In early July, 1984, CH2M Hill performed
pilot tests of the mid-canyon groundwater interception well
system to verify the long-term pumping rate required to effec-
tively intercept contaminated groundwater moving through the
mid-canyon area.
CURRENT SITE STATUS
Hazardous Substances Present
Table 1 presents a summary of the concentration ranges for
major contaminants present in the groundwater at the Stringfellow
site. Analytical results for upgradient water are from spring
water samples collected north of the disposal area; this is an
indicator of background levels of groundwater constituents in
Pyrite Canyon.
High concentrations of heavy metals present in the contaminated.
groundwater found onsite include chromium, cadmium, copper and
zinc. In samples collected from onsite wells, nitrate, sulfate
and chloride levels are one to two orders of magnitude higher
than background samples. Onsite water ranges in pH from 2.6 to
4.1, significantly more acidic than upgradient water (pH 7.0 to
7.2). A wide range of organic pollutants are present in the
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TABLE 1
CONCENfRAflON RANGES FOR SELECf[D CONSflfUENfS
IKRADIENf ON-SIfE IJIII£R CANYn MID CANYON LOW:R CANYON PRIVAfE W:US
Spr inga I W-Z, ) Weat Side hat Side
Above MM-1B, ZB, MW-1.B, See
Dlepoe8. 1W-1, ...)8 7B, 88, 98, MW-108, nB, 16B, r IfJure s..1
Area 0W-1.2.- -B. S8. 6B nB 11B. 12B 17B. 1BB hble 5-1
Inol'Q8nlee (-VI)
Chr_iU8 tI) 1.S-Z10 --170 --2.. NO NI).4.0~ NI).4.7. (1
C"IU8 NO 0.12-7.) NO-9.J NO-J.. NO NO ND-O .006
Copper NO 1.7-Z0 NO-ZB ND-O.Z6 NO-O.059 .NO ND-{J.11
Le" NO ND-Z5 NO-Z.1 NO-1.70 NO NO NO
MIInge.... O.022-0.n 100- JRO NO-1200 NO-}l5 ND-O.1. ND-O. 52 --J.J
Zinc fD-O.028 2.Z-110 NO-JOO NO-Z9 ND-0.Z.5 ND-O.09 NO-5.6
NUnt..... --).9 8-120 10-100 NO-115 9.6-Z6 NO-9B Z ..-no
Sui rat. ND-)IS )200-JRooo 1000- Joooo 17O-Z7OOO 180-1500 100-1}OQ .s..UO
Chloridlt 61-10 9)-5800 Z.S...OOO 60-850 J7-J10 .S-JOO Z6-)}0
"pH 1.0-1.2 2.6-..1 Z.7-6.5 ).0-7.J 6.5-7.6 6.8-7.6 6.Z-8.1
Ol'Q8nlee (ug/I)
,.....1 tI) ND-6.u --1600 --(100 --(10 NO NO
1,Z~lehlorab8nzanl NO 1 ZO-)8oo 170-2.00 ~OO NO-12 ND-(ZO NO
1,-~iehlorobenzene NO 59-1200 18-660 NO-1. NO-(10 NO NO
I eaphor0f8 NO 190-)600 NO-51oo -- J.u NO NO NO
Chlorab8nzenl NO 290-1800 50-1200 NQ-140 NO-
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onsite and downgradient groundwater. The organic pollutants in
the greatest concentrations are 1,2-dichlorobenzene, isophorone,
methylene chloride, trichloroethylene (TCE), chloroform, acetone
2-butanone, and 4-methyl-2-pentanone. Traces of pesticides
(4,4'-DDT and 4,4'-DDE) are also present. .'
Recent analytical work performed by the National Enforcement
Investigation Center (NEIC) has revealed chlorobenzenesulfonic
acid (CBSA) as a contaminant in the groundwater at Stringfellow.
Analysis for this substance had not been performed previouSly
because it is not a priority pollutant. Concentrations of CBSA
were as high as 2000 mg/l in samples taken from onsite wells.
CBSA is an industrial by-product of DDT production and is usually
found in the sulfuric acid wastes from this process. Relatively
little toxicological data exists for CBSA and an analytical
protocol is being developed. Analysis for CBSA will be included
in the next monthly sampling effort.
."
NEIC's analysis also revealed gross alpha radiation levels ranging
from 38 to 672 picocuries/liter in sampes take from onsite wells
and IW-2 and IW-3 (see Figure 2). To follow-up on these findin9S,
DOHS is conducting sampling of upgradient, on-site, downgradient
and Glen Avon community wells to determine the extent and source
of radiation contamination. Two hundred and twenty-six samples:
have been taken following a door-to-door canvass of 1600 residences
and businesses in Glen Avon to locate wells.
On June 11 and 12, 1984, samples were taken from three large
water purveyors in Glen Avon. Radiation analyses conducted by
the Department's Sanitation and Radiation Laboratory show that
the water delivered by these systems meets the State and Federal
drinking water standards for radioactivity. Results of analyses
performed on samples from 14 domestic wells taken the week of
June 6, 1984, show gross alpha activity ranging from negligibl~ to
31.3 picocuries per liter. Two of these domestic wells are in
compliance with Federal drinking water standards for gross. alpha
radiation; further analysis must be conducted on the other twelve
samples.
As a precautionary measure until the sampling and analysis is
complete, DOBS is providing bottled water to approximately 39~
Glen Avon households who normally obtain their drinking wat.er
from private wells or from the small public water purveyor,
Felspar Gardens Mutual Water Company. Bottled. water is bein~
paid for through emergency provisions of the State's Superfund
program.
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Extent of Contamination
Information on groundwater quality consists primarily of
analytical results from samples collected by E & E during
1983. Samples were collected from 3 extraction wells (OW-I,
OW-2, OW-4), 3 interceptor wells (IW-I, IW-2, IW-3), 18 down-
gradient monitoring wells, and private wells in the community
of Glen Avon. (Refer to Figures 1 and 2.)
A report issued by E & E in May, 1984, concludes:
- TCE is the primary organic contaminant present in groundwater
downgradient of the disposal area. Organic contaminants
other than TCE and chloroform have attenuated significantly
before reaching lower Pyrite Canyon.
- Downgradient migration of significant quantities of metals is
confined to the upper and mid-Pyrite Canyon areas (approxi-
mately 1,200 feet offsite).
- Sulfates and chlorides have migrated to the lower canyon area.
No contamination related to the disposal site has been detected
in any of the private wells included in the monitoring program.
- The main axis of the contaminant plume appears to run along
the eastern side of lower Pyrite Canyon past MW-lSB and MW-l7B.
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- Data concerning vertical stratification of contamination
suggests that contamination is distributed throughout the
aquifer thickness.
The full-scale RI/FS will obtain information necessary to
better define the potential areal and vertical extent of the
groundwater contaminant plume.
Pathways of Migration
Interpretation of the EM conductivity survey suggests that plume
movement is strongly controlled by the location of buried
channels in the alluvium.
Alluvium is probably the main water-bearing material in Pyrite
Canyon. The alluvium is permeable and varies in thickness
from 10 feet at the south end of the site to 80 feet at the
mouth of the canyon. The alluvium in the lower parts of the
canyon is made up of distinct layers of clay, sand and gravel
.as opposed to its more heterogeneous nature in upper parts of
the canyon. Older alluvium rests on the weathered bedrock
surface and consists primarily of dense sand with gravel and
boulders of highly weathered granodiorite.
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No information is available on the water-bearing characteristics
of the weathered, fractured, and jointed bedrock, but water
could be contained within these features, and, if inter-connected
these features may transmit water for certain distances. A
detailed investigation of alluvium and bedrock pathways of
migration will be conducted in the full-scale RI/FS.
The depth to groundwater ranges from 10 to 40 feet. Ground-
water velocity ranges from 50-3,500 ft/year depending on location.
Velocity is lowest in the silty, clayey sediments near the canyon
walls and highest in the central portion of the valley. The
average groundwater velocity is estimated to be about 1,200
ft/yr. In the mid-canyon area, average groundwater under-
flow is estimated to 40 gpm.
Potential receptors
Numerous private wells are located downgradient of the site.
In a recent survey of the private wells in Glen Avon, over 200
private wells were located directly downgradient of the site.
Groundwater exiting the canyon mixes with the Chino Basin aquifer
which provides a domestic drinking water supply for approximately
40,000 potentially affected residents and is used for industrial
and agricultural purposes.
Exposure Potential
Section 300.68(e) of the National Contingency Plan (NCP) directs
~hat the extent to which contamination poses a danger to public
health, welfare, or the environment be assessed in order to
determine the appropriateness of proposed remedial actions. In
order to comply with this requirement, an endangerment assessment
of the groundwater conditions in the vicinity of IW-2 and rW-3
was conducted to determine the extent to which contamination
poses a danger to public health, welfare or the environment.
The endangerment assessment addressed the likelihood that
contaminated groundwater will reach downgradient domestic wells
within the next three years. This is the minimum time anticipated
before final remedies can be implemented.
For the purpose of the endangerment assessment, 8 key constituents
were identified: trichloroethylene (TCE), chloroform, cadmium,
chromium, methylene chloride, isophorone, lead, and nitrate.
Because TCE and chloroform are mobile in the groundwater environ-
ment, they present the greatest immediate danger to downgradient
groundwater users. Their presence has been verified 4,000 feet
south of the disposal area. .
Monitoring well data shows TCE levels consistently above the
California action level of 5 ug/l and EPA's 10-6 Water Quality
Criteria of 2.7 ug/l. Chloroform has been found at levels
consistently above the State action level of 2 ug/l and EPA's
10-6 Water Quality Criteria of 0.19 ug/l in all but one well.
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-8-
The highest average values found of TCE and chloroform are
1,600 ug/l and 230 ug/l, respectively.
TCE is a halogenated hydrocarbon of relatively low acute t~xicity,
but in high doses can cause central nervous system depression,
long-term neurological effects, dermatitis, and peripheral
neuropathies. Liver toxicity has been observed in high dose
animal studies and in humans at anesthetic doses. The status
of TCE asa potential human carcinogen is not fully resolved,
but is a proven animal carcinogen. Chloroform can cause nausea,
dizziness, and acute central nervous system depression. Chloro-
form can also cause chronic liver and kidney damage.
Heavy metal contamination can cause damage to the central
nervous system, liver, kidneys, gastrointestinal tract and
respiratory tract. Some of the heavy metals identified for the
have been found to be carcinogenic, teratogenic and/or mutagenic.
Calculations of contaminant movement were made in the endanger-
ment assessment. Based on anticipated dilution effects, it
is estimated that in 2.5 years the levels of TCE in the area
of the nearest domestic well (3,200 feet downgradient from IW-2
and IW-3) could be between 150 and aOo ug/l and the levels of
chloroform could be between 20 and 110 ug/l. These levels are
much higher than the action levels; therefore, it was concluded
that a significant threat to public health exists due to ground-
water contamination from the site.
I
,
The results of the endangerment assessment show the need for
interim extraction of contaminated groundwater from mid-canyon
prior to completion of the full-scale RI/FS and implementation
of the final remedy. This interim measure will effectively
prevent migration of contaminants toward domestic wells down-
gradient of the site and will thereby abate the threat to
public health.
A comprehensive health assessment is currently being conducted
by DOHS and a more com~rehensive endangerment assessment may
be performed during the full-scale RI/FS.
ENFORCEMENT
potentially Responsible Parties (PRP)
In August and October, 1982, EPA issued over 200 combination
CERCLA section 104/RCRA section 3007 Notice Letters to potentially
responsible parties. The government negotiation team which
consists of EPA, DOHS, the United States Department of Justice
(DOJ) , and the State of California Attorney General held a
general meeting with potentially responsible parties in November,
1982. The purpose of this meeting was to initiate enforcement
discussions with potentially responsible parties to recover past
-------
-9-
and future costs of cleanup. On"April 21, 1983, the United
States and the State of California filed a civil suit in the
united States District Court for the Central District of
California. Eighteen generators, 4 transporters, and 9
owner/operators were named as defendants in the lawsuit.
A record of disposal activities at the Stringfellow site exists
in 35,000 pages of Stringfellow business records. NEIC has had
this information put into a computer data base and is able to
generate summaries of the information.
Litigation Status
- Discovery
The case is presently in the discovery phase of litigation.
Both the defendants and the plaintiffs have, and continue
to, produce documents, propound interrogatories, and conduct
depositions. Additionally, the plaintiffs have served requests
for admissions on defendants: these requests are for admission
that the Stringfellow business records are genuine and admiss-
ible documents.
- Settlement
In October, 1983, the United States presented two settlement.
options to defendants. Option 1 would allow the potentially
responsible parties to perform the RI/FS and to implement the
resulting remedial actions, both under the supervision of EPA
and the State. Option 2 would allow EPA and the State to
perform the RI/FS and to implement the resulting remedial
actions: the defendants would pay 100% of the cost. The
defendants settlement negotiations. EPA has offered to resume
settlement discussions at any time convenient to the defendants.
- Motions
Judge Malcolm Lucas issued his ruling on the issue of Joint
and Several Liability on April G, 1984. The ruling grants
Joint and Several under CERCLA Sl07, but needs further clari-
fication on the applicability of Joint. and Several under.
CERCLA SlOG.
As with the ruling on Joint and Several Liability, the ruling
on Retroactivity will need further clarification before a full
understanding of its implications is realized.
The motion for intervention, submitted by members
community, was granted as permissive intervention
conditions. The appeal on this ruling was denied
court.
of the
with
by the
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-10-
The Court has issued ambiguous rulings on the issues of joint and
several liability and retroactivity. A status conference before
a newly assigned jUdge was heard on June 18, 1984. The Court
has set August 20, 1984 as the deadline for the filing of future
motions; motions filed by this date will be heard on October 1, .
1984. EPA and the State are considering filing motions for
partial summary judgment and issuing an administrative order
under CERCLA Sl06.
ALTERNATIVES EVALUATION
Remedial Objectives
The objective of the Fast Track RI/FS is to identify an interim
measure that would prevent migration of additional contaminated
groundwater past mid-canyon and, as a result, would prevent
adverse public health and environmental impacts during the 3 - 5
year period prior to completion of the full-scale RI/FS and
implementation of the final remedy. The measure should provide
cost-effective management for disposal of groundwater collected
from onsite and downgradient wells.
Alternatives Considered
t
i
The following interim remedial actions were considered:
- No action
- Discharge to a publicly owned treatment works (POTW)
- Pretreatment followed by discharge to a POTW
- Reinjection (either onsite or offsite)
- Treatment followed by reinjection
Solar evaporation
- Incineration
- Surface discharge
- Treatment followed by surface discharge
- Disposal at a Class I land disposal site
- Disposal at a Class 11-1 land disposal site
- Disposal at a permitted hazardous waste treatment facility
- Reuse as industrial process water
- Future treatment of drinking water at the tap
Initial Screening of Alternatives
As required by the National Contingency Plan, (40 CFR 300.68(h»,
the above alternatives were initially screened using the criteria
of estimated cost, effects of the alternative, and acceptable.
engineering practices. The following alternatives were eliminated
from further consideration:
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-11-
- No Action
As required by Section 300.68 (e) of the NCP, an assessment
of the groundwater conditions was conducted to determine the
extent to which continued migration of groundwater contamina-
tion poses a threat to public health, welfare, or the environ-
ment. The endangerment assessment addressed the likelihood
that contaminated groundwater will reach downgradient domestic
wells within the next three years. This is the minimum time
anticipated before a final remedy can be implemented. Based
on findings of the endangerment assessment, it was concluded
that a significant threat to public health from migration of
contaminated groundwater would exist within 2.5 years if no
interim action were taken. (Refer to pages 7 and 8 for a
discussion of public health concerns.) Therefore, the
"no-action" alternative was eliminated from further
consideration.
- Discharge to a Publicly Owned Treatment Works Without
Pretreatment
Two POTW systems were identified as tentatively suitable for
receiving extracted groundwater. Each POTW has water quality
limitations for industrial wastes discharged to its system.
Because untreated Stringfellow water exceeds the water quality
limitations of both systems and could not be discharged to
either without pretreatment, this alternative was eliminated.
- Reinjection Without Treatment
Geologic and hydrogeologic data required for implementation
of this alternative is unavailable at this time. Aquifer.
characteristics will be fully studied in the full-scale RI/FS
and this alternative may be reconsidered at that time.
However, without adequate knowledge of the hydrogeology of
the area, reinjection could actually accelerate migration of
contaminated groundwater. Therefore, this alternative is
unacceptable at this time.
- Treatment Followed by Reinjection
As with the alternative, "Reinjection Without Treatment",
extensive geologic and hydrogeologic information is required in
order to assess the impacts of this alternative. This informa-
tion is not currently available. This alternative may be recon-
sidered in the full-scale RI/FS but is unacceptable at this time.
- Solar Evaporation
No suitable land area was identifieq. Establishment of surface
impoundments for solar evaporation either in pyrite Canyon or
elsewhere in the vicinity was judged to be unacceptable to the
surrounding community. It should be noted the existence of the
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-12-
Stringfellow site as an uncontrolled hazardous waste site is
due to a failed attempt at solar evaporation. Community and
local agency opposition to a second attempt at onsite solar
evaporation was anticipated to be strong and could preclude
timely implementation of this alternative.
- Incineration
EPA is unaware of any suitable incineration facilities in close
proximity to the site, thus a facility would have to be con-
structed onsite. Since prefabracated components for this type
of facility are not available, the extensive time requirements
for design and construction render this alternative inappropri-
ate as an interim solution. Due to the complexity of this
type of facility, the capital costs of construction would be
high: due to the low heating value of water, energy costs
would be prohibitively expensive.
- Surface discharge
Surface discharge of extracted contaminated ground water could
cause extensive surface water and soil contamination and would
violate existiug water quality criteria. This alternative may
not mitigate the current ground water problem table resulting r
in even further migration of the contaminant plume. In addition,'
it presents a threat to public health as a result of consumption
of or direct contact with contaminated water.
- Treatment Followed by Surface Discharge
A pretreatment facility would be built on-site. Treated efflu-
ent would be discharged to Pyrite Creek which flows through
the community of Glen Avon in lined and unlined channels to
the Santa Ana River. This alternative would require extensive
removal of contaminants to meet existing water quality criteria
due to the low dilution capacity of Pyrite Creek. The costs
associated with this level of treatment would be high. In the
event of a treatment system failure, a release of contaminated
water could result in surface water and soil contamination,
and could create a potential threat to public health due to
volatilization of organics and the potential for consumption
of or direct contact with contaminated water.
- Disposal at a Permitted Hazardous Waste Treatment Facility
There is one permitted hazardous waste treatment facility in
southern California. Treatment at the facility consists of
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-13-
neutralization, settling, and sludge dewatering. Dewatered
sludge is disposed of onsite and treated effluent is discharged
to an industrial sewer which connects to a POTW. The facility's'
treatment process for contaminated groundwater from the String-
fellow site may not produce an effluent which would comply
with the POTW pretreatment standards since the process is not
designed to remove organic contaminants. Moreover, the facility's
limited capacity and current customer loading makes it inadequate
for expected Stringfellow quantities.
- Reuse as Industrial Process Water
Demand for contaminated water in industrial facilities is
limited. EPA is unaware of any industrial facility in close
proximity to t~e site that could use contaminated water. In
addition, this alternative may present a public health hazard
due to the potential for employee exposure to volatile emissions
from the contaminated water. Furthermore, a potential exists
for mishandling the contaminated wastewater after it has been
used as process water. Thus, this alternative may present a
threat to public health and the environment.
- Future Treatment of Drinking Water at the Tap
r
I
This alternative does not achieve the remedial objectives of
preventing the migration of additional contaminated groundwater~
thus the entire Chino Basin aquifer may ultimately be contamina~
As a result, an expanded tap water treatment program would be
required. This alternative would not alleviate environmental
problems and may worsen long-term problems by allowing further
contamination of the groundwater basin.
Detailed Description of Remaining Alternatives
The remaining alternatives were evaluated regarding their
effectiveness in meeting the remedial objectives of the Fast-
Track RI/FS and on the basis of cost. In addition to operation
of the existing facilities, as proposed in the Fast Track, the
following components are common to all three of the remaining
alternatives:
- Storage Tanks and Containment Structure
In order to effectively intercept contaminated groundwater
in the mid-canyon, the Fast Track determined that groundwater
should be extracted at an average rate of 40 gpm. An additional
200,000 gallons of onsite storage capacity is needed to accomo-
date the total flow. This will provide 3 days of storage
capacity. In addition, it is necessary to install a concrete
containment structure around the storage tanks to prevent
flow of contaminated water down the canyon in the event of a
spill and to divert storm runoff from the storage tank area.
Design and construction of storage tanks and a containment
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-14-
- Gunite Channels
In order to alleviate the existing surface water runoff and
soil erosion problems, the existing eastern and western
gunite channels should be extended. Specifically, the eastern
channel should be extended past the Baker tanks and a culvert
should be installed beneath the road to carry runoff. The
western channel should be extended to connect with flows
from the east prior to discharge to Pyrite Creek. (See Figure
2.) Extension of the gunite channels and installation of a
culvert is estimated to cost $110,000.
- Piping
The piping for conveying flow from the spring upgradient of
the site to the eastern gunite channel is damaged and causes
a surface runoff and infiltration problem. A permanent
conveyance consisting of new piping extending all the way to
the channel is required. (See Figure 2.) The estimated cost
of this component is $3,500.
- Interceptor and Monitoring Wells
Additional interceptor and monitoring wells are required to
assure effective interception of contaminated groundwater in
the mid-canyon area. The estimated cost of this component is
$110,000.
I
,
A description of the three remaining alternatives follows:
- Alternative 1:
Pretreatment Followed by Discharge to a POTW
A pretreatment facility would be constructed at the Stringfellow
site. The treated effluent would be trucked to a local POTW
system drop point for discharge effluent would receive secondary
treatment at the POTW. The sludge would be disposed of at a
Class I facility. The POTW system which receives the pretreated
water would establish the level of pretreatment through the
issuance of a discharge permit.
.The Los Angeles County Sanitation District (LACSD) and the
County Sanitation Districts of Orange County (CSDOC) were
identified as candidates for disposal of pretreated Stringfellow
water because they have marine discharge points and system drop
points close to the site (less than 15 miles).
The Chino Basin Municipal Water District (CBMWD), which
discharges to the LACSD, and the Santa Ana Watershed Project
Authority (SAWPA), which discharges to the CSDOC, have estab-
lished discharge requirements. Contaminated water at the
site bears similarities to metal finishing industry wastewater,
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-15-
containing both heavy metals and organic solvents. In absence
of categorical treatment requirements, the most stringent
requirements of CBMWD, CSDOC, SAWPA and EPA PSNS (pretreatment
standards for new sources) were set as goals to be met by
the recommended alternative. Table 2 summarizes these pre-
treatment objectives.
Before this alternative could be fully evaluated and cost
estimates prepared, a review of treatment technologies was
conducted to determine the optimal pretreatment process for
Stringfellow groundwater. Based on the types and locations
of contaminants present at the site, two basic treatment
operations would be required to satisfy the discharge objec-
tives identified. These operations are heavy metals removal
and organics removal.
The basic technologies for removal of heavy metals are
precipitation and concentration. The following treatment
processes were evaluated: alkaline precipitation, sulfide
precipitation, ion exchange and reverse osmosis. The following
organics removal treatment technologies were evaluated:
stripping, oxidation, adsorption, solvent extraction and
membrane separation.
Based on an analysis of complexity of operation, probability
of achieving desired removal, relative capital costs, relative
operation and maintenance costs, potential operating problems, .
and types and potential volumes of residues generated, it
was determined that the most effective system for treating
Stringfellow groundwater would consist of lime precipitation
for heavy metals removal followed by granular activated
carbon treatment for organics removal. (For a discussion of
the different treatment technologies, refer to the Final
Fast Track RI/FS.) Thus, this system was used as a basis for
evaluating this alternative.
r
I
- Alternative 2:
Disposal at a Class I Land Disposal Site
The current practice of hauling extracted groundwater to
a Class I disposal site would be continued. Class I disposal
sites are State-licensed facilities permitted to accept the
broadest categories of hazardous wastes. Stringfellow ground-
water is currently disposed of at the Casmalia Resources, Inc.
facility in Santa Barbara County, a distance of about 210
miles from the Stringfellow site.
- Alternative 3:
Disposal at a Class 11-1 Land Disposal Site
Extracted groundwater would be disposed at a Class 11-1
disposal site. Class 1I-~ land disposal sites are State-
licensed facilities permitted to accept prescribed quantities
of specified waste types. From a list of all of the 11-1
facilities in California, only two sites have been identified
as potentially suitable sites based on capacity, and types of
-------
TABLE 2
PROPOSED PRETREATMENT OBJECTIVES
Constituent
Maximum Conc.
(mg/l)
Arsenic
Cadmium
Chromium (T)
Copper
Lead
Mercury
N i cke 1
S i 1 ve r
Zinc
Cyanide (Total)
Cyanide (Amenable)
PCB's & Pesticides
Total Toxic Organics
Sulfide (Total)
Sulfide (Dissolved)
Oil or Grease
BOD
COD
TSS
pH
2
0.11
0.5
2
0.69
0.03
3.98
0.43
2.61
1.20
1
0.02
0.58
5
0.5
100
250
5000
300
6-9 (pH
I
I
units)
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-16-
waste accepted. These facilities are operated by Environmental
Protection Corporation (EPC). Facilities at both sites consist
of lined surface impoundments for solar evaporation. Remaining
solids and sludges are landfilled in a lined disposal area.
These facilities are approximately 170 miles from the Stringfellow
site.
Detailed Evaluation of Alternatives
The effectiveness of these alternatives was evaluated on the basis
of cost, public acceptability, public health, environmental and
technical considerations. Eight criteria were developed to evalu-
ate these factors:
Time:
How much time is required to implement the alternative?
- Compatibility: Can the alternative be easily adapted to the
final remedy to be identified in the full-scale RI/FS (i .e.',
could it be modified or discontinued easily)?
- Reliability/Risk of Failure: How reliable would the alternative
be based on the operating characteristics of the processes and
equipment involved? This criterion applies to the technology
status of processes used onsite and at the receiving facility.
t
I
- Level of Site Cleanup:
achieve site cleanup?
To what degree will the alternative
- Community Impact: Will the alternative have an acceptable effect
on the residents of Glen Avon and other potentially affected
communities?
Technology Status: Is the technology well-established or experi-
mental? This criterion applies to the technology status of
processes used on-site and at the receiving facility.
- Potential Environmental Impacts: What environmental impacts,
either positive or negative, would be expected to result from
the alternative? This criterion applies to the potential
environmental impacts as a result of operations at the site,
during transport and at the site of ultimate disposal.
- Complexity of Operation: How difficult would it be to operate
the components of the alternative? This criterion applies to
the complexity of operations at the site and at the receiving
facility.
- Cost: Annual and total three-year cost estimates were developed
for each of the three alternatives because the selected alterna-
tive will be used on an interim basis until a final remedy is
implemented.
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-17-
A summary effectiveness evaluation and estimated cost for each
alternative is presented in Table 3. A comparative evaluation of
the alternatives follows:
- Time
Alternative 2 has an advantage over the other two alternatives
for time to implement since it is currently being practiced
on a reduced scale. Implementing this alternative would require
contracts for more trucks to transport the additional flow and
to install additional storage capacity. It is estimated that
this alternative could be implemented in 2 to 4 months.
As with Alternative 2, implementation of Alternative 3 would
require installation of additional storage capacity and
obtaining additional hauling trucks. In addition, it may be
necessary to amend the current hauling contract to specify a
new destination and negotiations must be conducted with the
II-l facility. It is estimated that this alternative could
be implemented in 2 - 5 months. The current practice of
disposing of extracted groundwater at a Class I facility would
be continued until this alternative could be implemented.
It is estimated that design and construction of Alternative 1
would take 6 to 9 months. The current practice of disposing
of extracted groundwater at a Class I facility would be con-
tinued until the pretreatment plant is on-line.
I
J
- Compatibility
Alternatives 2 and 3 are judged to be equal with respect to
compatibility with the future remedy and to have a slight
advantage over Alternative I since they can both be discon-
tinued or modified with minimal cost on short notice and do
not require a large capital investment.
While not as easily discontinued as Alternatives 2 and 3, the
treatment system for Alternative I would be made of pre-fabricated
components which may be modified to accomodate changes in
waste characteristics and flow quantities. Pending the results
of" the full-scale RI/FS, the the treatment plant may be adapted
to operate as a component of the final remedy.
Alternative 3 is less flexible than Alternatives 1 or 2 in
accomodating changes in waste characteristics and flow quantities
since Class 11-1 facilities can only accept specified types and
quantities of wastes.
- Reliability/Risk of Failure
Onsite: Due to the complexity of operations of a treatment
plant, Alternative 1 may have a greater risk of failure than
Alternatives 2 and 3 which only require extraction and loading
activities at the site.
-------
Alternative
1. Pretreatment
Followed by
Discharge to
a POTW
2. Disposal at
Class I
Facil ity
Cost ($1,000)*
Present
Capital Worth
$1,240
$9,189**
$14,660
TABLE 3
SUMMARY OF COSTS AND EFFECTIVENESS EVALUATION
STRINGFELLOW, CA
public Health
Considerations
- Will effectively
prevent migration
of additional
contamination there-
by reducing the
future threat to
public health in
the nearby community;
Minimal or no threat
to public health in
communities served
by the receiving
POTW.
- Will effectively
prevent migration
of additional
contamination
thereby reducing the -
future threat to
public health in the
nearby community:
May present public
health hazard to
other communities
in the event of
mishandling during
transport or disposal.
Environmental
Considerations
- Will effectively
remove contaminated
groundwater from the
site.
- Low potent~al for
adverse impacts
due to: transport of
treated effluent;
secondary treatment
at the receiving
POTW; and dilution
with marine discharge.
- Will effectively
remove contaminated
groundwater from
the site.
Potential for
adverse impacts
related to highway
spills or accidents:-
Potenial for adverse
impacts related to
improper or inade-
quate disposal at
receiving facility.
Technical
Considerations
- Proven technology
utilized onsite
and at receiving
POTW.
- Relatively complex
operations required
onsite and at
receiving POTW.
- Risk of Failure for
onsite operations
greater than for
Alternatives 2 , 3:
Risk of Failure during
transport less than
Alternatives 2 , 3:
Greater reliability at
receiving facility.
- Six to nine months
to implement.
- Process components easily
modified to accomodate
changes in waste character-
istics and flow quantities.
- Proven technology.
- Low complexity of oper-
ations onsite and at
receiving facility.
- Risk of failure low for
onsite operationJ
potentially high during
transport and at
receiving facility.
All but two Class I
facilities in California
have confirmed significant
(class 1) RCRA violations.
- Two to four months to
implement.
- Easily discontinued.
Public
Comment
- supported
by community.
- Limited
comment:
Less
acceptable
than Alter-
native 1.
-------
Alternative
3. Disposal at
Class 11-1
Land Disposal
Facility
i
i .
Cost ($1,000)*
Present
Capi tal Worth
$ 9,770
..,
TABLE 3 continued
SUMMARY OF COSTS AND EFFECTIVENESS EVALUATION
STRINGFELLOW, CA
Public Health
Considerations
Environmental
Considerations
Technical
Considerations
- Proven technology.
- Relatively low
complexity on
site and at
receiving facility.
- Risk of failure low
for onsite operations,
potentially high during
transport and at
receiving facility.
- Two to five months to
implement.
- Easily discontinued.
Less flexible than Alter-
natives I and 2 in accomo-
dating changes in waste
characteristics and flow
quantities.
Public
Comment
- Limited
commentz
Least
acceptable
alternative.
* Costs based on 60 gpm continuous flow, 3 years, 10% annual interest, no facility salvage value, monthly
payments. Note that the costs presented do not include the cost of the following elements which are common
to each alternative and were described on page 15: additional storage capacity, gunite channel extensions
piping and additional interception and monitoring wells. The total estimated cost of these items is $1,023,000.
** Cost does not include disposal of sludge I this cost is considered insignificant in relation to the total
cost of the alternative. The preliminary cost estimate for sludge disposal is $35,000/year.
- Will effectively
remove cont~minated
groundwater from
the site.
the - potential for
adverse impacts
related to highway
spills or accidents:
potential for adverse
impacts related to
improper or inade-
quate disposal at
receiving facility.
- will effectively
prevent migration
of additional
contamination
thereby reducing
future threat to
public health in the
nearby community:
May present public
health hazard to
other communities
in the event of
mishandling during
transport or disposal.
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-18-
During Transport: Since untreuted waste must be transported
for about 210 miles for Alternative 2 and about 170 miles for
Alternative 3, these alternatives have relatively greater
risks of failure than Alternative 3 during transportation due
to the greater potential for traffic accidents.
The risk of failure for Alternative 1 is low since pretreated
effluent is only transported for a distance of about 15 miles
and conveyance of the pretreated waste once it reaches the
sewer system is considered to be of extremely low risk.
Receiving Facility: Alternative 1 is most likely to consistently
provide the level of operation and maintenance required to
~ssure effective, safe handling of wastewater. In the past,
some Class I and 11-1 Land Disposal facilities have violated
RCRA groundwater monitoring and surface impoundment containment
and maintenance requirements. To date, all but 2 Class I
facilities have substantial (class 1) RCRA violations. Thus,
Alternatives 2 and 3 are considered to be less reliable than
Alternative 1.
- Level of Site Cleanup
All three alternatives would effectively attain site cleanup
since they entail removal of contaminated groundwater from
the site and effectively prevent migration of additional
contamination downgradient.
Alternative 1 may result in a greater level of overall clean-
up since the waste is treated in two stages. First, the on-
site facility will remove a large amount of contaminants to
meet discharge requirements of the receiving POTW. Second,
the water will be treated again at the POTW prior to ocean
discharge.
- Community Impact
Since all three alternatives entail removal of contaminated
groundwater from the site and effectively prevent migration
of additional contamination downgradient, all three alterna-
tives would have positive impacts on the community of Glen
Avon and other neighboring communities.
Alternatives 2 and 3 may adversely affect other communities
in the event that improper or inadequate disposal and/or
. transport results in contamination of groundwater or surface
water.
Alternative 1 is not expected adversely affect the community
in which the POTW receiving pretreated effluent is located.
since this effluent will be similar to or less hazardous than
effluent from other industrial sources and only represents a
small percent of the POTW's capacity.
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-19-
Alternative 1 is generally supported by the community, Alterna-
tive 2 is less acceptable and Alternative 3 is the least
acceptable.
- Technology Status
All three alternatives utilize proven, commonly practiced
technologies that when properly maintained and operated are
effective.
- Potential Environmental Impacts
Onsite: All three alternatives will have positive environmental
impacts at the site since all three entail extraction of
contaminated groundwater and thereby prevent migration of
additional contaminants.
During Transportation: Concern for spills or exposure during
transport of waste to the point of disposal is great. In
the event of an accident during transportation, Alternatives
2 and 3 have relatively greater potentials for adverse environ-
mental impacts since untreated water will be transported.
A spill could result in contamination of soil, surface water
and/or groundwater.
Ultimate Disposal: Under Alternative 1 treated effluent would
ultimately be jischarged to the ocean. In the event of a
failure of the onsite treatment facility or the POTW, or
both, this alternative can be expected to have minimal adverse
environmental impacts due to the large dilution factor of
marine discharge. In addition, water will be treated twice
prior to marine discharge under Alternative 1.
I
I
Alternatives 2 and 3 are more likely to cause adverse
environmental impacts in the event of inadequate or inappro-
priate disposal of Stringfellow groundwater at the receiving
facilities since contaminated water may percolate to ground-
water.
Alternative 1 would generate sludge during the pretreatment
process. This sludge will be disposed of in a Class 1 landfill.
Alternative 1 would use activated carbon that becomes contaminated
during the treatment process. This "spent" carbon will be
regenerated by high temperature incineration for reuse.
- Complexity of Operation
Onsite: Alternatives 2 and 3 have the least complex' operation
requirements for onsite activities since only pumping and
storage is required. Alternative 1 requires more sophisticated
operation activities.
Receiving Facility: The receiving facilities for all three
alternatives have 0 & M procedures in place since they are
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1-
-20-
operating facilities, thus this factor is considered relatively
insignificant.
- Cost
Cost estimates were calculated for each of the alternatives
based on the following assumptions:
- 60 gpm average continuous
- 3 year operations
- 10% interest rate
- no facility salvage value
flow
(31,536,000 gallons/year)
Alternative 1: Treatment plant capital and operations cost
estimates for were prepared by CH2M Hill in the Fast Track
RI/FS. Transportation and disposal cost estimates were made
on the basis of information received from SAWPA and CBMWD
since completion of the Fast Track RI/FS. Note that the
cost of sludge disposal at a Class I Land Disposal facility
is considered to be insignificant relative to the overall
cost of this alternative and was not included in the following
cost estimates.
Capital Cost ($0.015/gal):
Operation Cost ($O.055/gal):
Transportation ($0.023/gal) &
Disposal to PQIW ($0.020/gal):
Present Worth Total 3 Year Cost:
$1,240,000
1,724,000/year
1,356,000/year
$9,189,000
Alternative 2: Cost estimates are based on the current cost
of extraction and disposal.
Extraction & Disposal Cost ($0.18/gal):
$5,676,000/year
$14,660,000
Present Worth Total 3 Year Cost:
Alternative 3: Extraction and disposal estimates were based
on preliminary pricing cost data received from EPC.
Extraction & Disposal Cost ($0.12/gal):
$3,780,000
Present WOrth Total 3 Year Cost:
$9,770,000
Based on the foregoing calculations, Alternative 1 is the
least cost alternative and is less expensive than both
Alternatives 2 and 3.
COMMUNITY RELATIONS
A community relations plan (CRP) was developed by DOHS in June,
1983. The State is planning to apply for a cooperative agreement
amendment to implement the alternative approved in this Record
of Decision. A revised CRP may be included in the amendment
application. A more comprehensive update will be completed in
J
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-21-
the fall of 1984.
A Stringfellow Advisory Committee (SAC) was established by DOHS
in September, 1983. The SAC consists of representatives from
community groups, elected officials, County and State agencies
and EPA. The first SAC meeting was held on September 23, 1983.
SAC meetings are held on a monthly basis.
Funding for a Community Technical Advisor (CTA) was provided in
the cooperative agreement. The CTA will provide the community
with technical review services throughout the RI/FS. SAC members
were actively involved in the selection process~ they interviewed
the top three caodidates in February, 1984 and made a recommenda-
tion to DOHS. The consulting firm, Environ, was selected to
be the CTA. SAC members were also involved in the selection
of the RI/FS contractor. They interviewed six of the firms
submitting proposals and provided comments to the State.
The following documents have been delivered directly to SAC
members for review and comment:
- RI/FS proposals
- RI/FS contract
- CTA Scope of Work
- CTA contract
- Fast Track RI/FS Work Plan
- Final Draft Fast Track RI/FS Report,
Final Fast Track RI/FS Report
Electro-magnetic Conductivity Survey
- Final Draft FIT Monitoring Well Completion Report
- Final FIT Monitoring Well Completion Report
- Final Draft FIT Site Summary Report
- SAWPA proposal
- selected RI/FS workplans
- fact sheets
r
,
The period for public comment for these documents
one to three weeks. The aforementioned documents
made available to other public agencies. Many of
were made availa~le to the public at large and to
responsible parties in the Stringfellow case.
ranged from
were also
these documents
potentially
The final draft Fast Track report was made available for Inter-
governmental Review from April 12, 1984 to May 21, 1984. The
final Fast Track report was available for public review from
May 21, 1984 to June 8, 1984. A notification for public comment
was advertised in southern California newspapers between May
4, and May 18, 1984.
Briefings on the Fast Track study were held by EPA during the
period February 15, 1984 to April 17, 1984 for the following
agencies: Orange County Sanitation District, Santa Ana Regional
Water Quality Control Board, Santa Ana Watershed Project Authority,
Orange County Health Department, Orange County Water Department,
U.S. Army Corps of Engineers, Chino Basin Municipal Water District,
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-22-
Orange County Board of Supervisors, and Los Angeles County San-
itation District. Potentially responsible parties were briefed
on February 10, 1984.
A public meeting was held by DOHS in Glen Avon on May 31, 1984.
Although EPA was prepared to discuss the Fast Track study, the
discussion focused on the radiation data recently released.
Although no formal comments were made at the public meeting,
the community is generally supportive of the alternative recom-
mended in the Fast Track report.
written comments on the Fast Track report were received from
several agencies and some potentially responsible parties.
These comments are addressed in the attached Responsivenp.ss
Summary.
CONSISTENCY WITH OTHER ENVIRONMENTAL LAWS
Two environmental laws that may apply to the proposed interim
measure have been identified. They are the Clean Water Act and
the Clean Air Act (S l18(a) and l7(c): 40 CFR 6.303(b». RCRA
requirements are not applicable at this time, thus a "RCRA
alternative" was not developed.
Alternative 1 complies with the Federal pretreatment requirements
of the Clean Water Act and local pretreatment standards developed
under the authority of the Act. The proposed pretreatment stand-
ards are presented in Table 2. The recommended alternative meet~
these requirements. In addition, the receiving POTW will be in
compliance with 40 CFR S270.60 (c).
Alternative 1 was reviewed to determine if requirements of the
Clean Air Act apply. If a proposed EPA actirin may adversely affect
air quality, the responsible EPA official is required to consult
with appropriate State and local agencies on whether the action
conforms with tha State Implementation Plan (SIP).
In response to the State Clearinghouse's request to comment on
the Stringfellow Fast Track RIjFS, the California Air Resources
Board wrote a memo, dated May 10, 1984, stating: "We believe
that the recommended remedial actions such as groundwater neutral-
iztion, lime treatment, filtration, and carbon adsorption will
have no adverse effect on air quality". Thus, we have concluded
that Clean Air Act requirements are not applicable to the recom-
mended alternative; however, air monitoring may be recommended
as a precautionary measure.
Although a "RCRA alternative" was not developed, on-site tanks
required by Alternative .1 will be designed to comply with RCRA
Part 264 Subpart J.
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-23-
RECOMMENDED ALTERNATIVE
Section 300.68(j} of the National Oil and Hazardous Substances
Contingency Plan (NCP) states that the appropriate extent of
remedy shall be determined by the lead agency's selection of the
remedial alternative which the agency determines is cost-effective
(i.e., the lowest cost alternative that is technologically feasible
and reliable, and which effectively mitigates and minimizes damage
to and provides adequate protection of public health, welfare, and
the environment). Based on evaluation of the cost-effectiveness of
each of the proposed alternatives, the comments received from
the public and the State, Region IX recommends Alternative 1,
Pretreatment Followed by Discharge to a POTW.
Alternative 1 is the least cost alternative. The estimated 3
year present worth of each alternative is listed below:
Alternative 1
Alternative 2
Alternative 3
$ 9,189,000
$14,660,000
$ 9,770,000
Alternative 1 is also considered to be the most effective alter-
native with respect to public health, environmental and technical
considerations. The main points made in the effectiveness
evaluation presented previously are summarized below:
t
I
- Although all three alternatives provide adequate protection of
public health to the communities neighboring the site, Alterna~
tive 1 is considered to be more effective overall. In the event
of mishandling during transport or disposal, Alternatives 2 and
3 may create a threat to public health to other communities.
Alternative 1 is unlikely to present this problem.
- All three alternatives effectively achieve site cleanup by
removing contaminated groundwater from the esite. Under Alterna-
tive 1, waste will be treated prior to transport and will receive
secondary treatment at the receiving POTW prior to marine
discharge. Thus, Alternative I is considered to have the least
potential for adverse environmental impacts.
- Although Alternative I has the most sophisticated operational
requirements, it is considered to be most reliable overall. In
the past, Class I and II-l Land Disposal facilities have violated
RCRA groundwatar monitoring and surface impoundment containment
and maintenance requirements. Thus, Alternatives 2 and 3 are
considered to be less reliable than Alternative 1.
- Alt.ernatives 1 and 2 are expected to be more compatible with future
remedial actions than Alternative 3 since Class II-l facilities
can only accept specific types and quantities of waste. Therefore,
a change in waste characteristics could require the use of a
different Class I1-l facility resulting in a disruption of site
operations and potential increase in disposal costs.
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-24-
The cost of Alternative I is somewhat less expensive than the
next costly alternative, Alternative 3. However, Alternative 3
is more sensitive to future cost growth if the volume of
contaminated groundwater increases due to changed site conditions
or seasonal variations. Disposal costs for Alternative 3 (and
Alternative 2) are directly proportional to volume of groundwater
disposed. However, the pretreatment system in Alternative 1
will have reserve capacity built in to accomodate some increase
in flows. Therefore, the only Alternative 3 costs associated
with increased flow would be higher operational costs that would
increase at a lower rate than off-site disposal costs.
- The local community supports Alternative 1.
Two POTW's were identified as potential recipients of Stringfellow
water for Alternative 1. Discussions were held with both of these
agencies to explore the possibility of this arrangement. The .'
Stringfellow site is located within SAWPA's jurisdiction. SAWPA
has submitted a proposal to DOHS for the purpose of implementing
the alternative recommended in the Fast Track report. DOHS is
supportive of Alternative 1 and has entered into a contract with
SAWPA in anticipation of EPA's approval of Alternative 1. DOHS is-
aware that EPA may not pay for any expenses incurred prior to .
selection of a remedy through the Record of Decision process.
capital, operating and disposal cost estimates for the recom-
mended pretreatment system are presented previously. A process.
flow diagram of the recommended pretreatment system is presented
in Figure 3.
Alternative 1 includes offsite disposal of sludge which is
consistent with CERCLA SlOl(24) in that it is part of the most
cost-effective remedial action and is necessary to protect
public health, welfare and the environment.
OPERATIONS
Annual operation costs in 1984 dollars are presented below.
Item
Annual Cost
Chemicals
$ 75,000
Lime - $30,000jyr
Caustic - $40,000/yr
Polymer - $5,000jyear
Granulated Activated
Power ($0.09/kwh)
Operating Labor
Monitoring
Carbon ($0.045/gal)
1,419,000
30,000
150,000
50,000
TOTAL
$1,724,000
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-25-
Effluent monitoring costs were developed for the following
parameters and sampling frequency: (1) Total Organic
Carbon (TOC) on a daily basis: (2) metals on a weekly basis:
and (3) priority pollutants on a monthly basis.
Given the interim nature of this activity, the costs of
operating the treatment plant will be considered an interim
offsite remedial measure. EPA will consider funding the
operation of the plant on an annual basis, pending availability
of funds, until a final remedy is implemented. If the treatment
plant is incorporated into the final remedy, EPA's policy to
pay for one year of 0 & M costs will go into effect at that time.
The State of California will pay a 10% cost-share of construction
and operational costs. The State's cost-share will be obtained
from the State Hazardous Substance Account or from the $4.2 ,"
million reimbursement funds paid to the State in the Stringfellow
Cooperative Agreement.
SCHEDULE
EPA anticipates the following schedule:
- Approve Remedial Action: July, 1984
- Amend Cooperative Agreement for Remedial Design, Construction
Management, Site Preparation and Operations: 4th Quarter FY'84
Begin Design and Site Preparation: 4th Quarter FY'84 .
Complete Design and Site Preparation: 1st Quarter FY'85
- Amend Cooperative Agreement for Remedial Action: 1st Quarter FY'85
- Begin Construction: 1st Quarter FY'85
- Plant on line: 2nd Quarter FY'85
- Operations: 2nd Quarter FY'85 - 2nd Quarter FY'88
t
,
FUTURE ACTIONS
- Long Term RI/FS
A full-scale RI/FS was funded under the cooperative agreement
with DOHS. JRB Associates (JRB) is conducting the RI/FS for
the State. The study commenced in March, 1984, and will be
concluded in October, 1985. JRB will conduct studies to
identify and evaluate methods to prevent or manage upgradient
groundwater and surface water entering the site, to prevent
migration of hazardous substances offsite, to define aquifer
characteristics, the extent of the contaminant plume, and
methods of controlling migration. JRB will develop a cost-
effective remedial action for final site closure.
- Interagency Agreement (lAG)
Through an lAG, the US Army Corps of Engineers will provide
EPA with technical assistance during remedial design of the
interim measur~ approved in the Record of Decision and during
the full-scale RI/FS.
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I~
-26-
- Remedial Action
Upon completion of the RI/FS, remedial design and remedial
action will be implemented for final site closure. . It is
anticipated that the State of California will apply for an
amendment to the cooperative agreement to implement final
site closure. The State will be expected to provide a 10%
cost-share for remedial action activities. It is anticipated
that a ROD for this purpose will be approved early in 1986.
-------
,
\
\
.. ...'
",
&-.~
3 I
..
,
Se.'e:
FIGURE 1
SITE ux:ATI~ & lDCATION OF
PRIVATE WELLS
o
,,..
'/2
MIL!
A
private well
Source :
Final Draft Stringfellow S\r.r.1ary Report,
Ecology & Enviroment, Inc.
l-ay' 16,1904,
prepared by
-------
FIGJRE 2
~ SITE PLAN
;
. ~ ~ '. I
.'(, ~....: . ~
,
'i
. I
Guwra '
DCAlNAH ''''''''
~""I.
. f.j~'~' .
,l"", ," I
,", .,'. .
,'/, ;
: I
, I
, '
, "
',I
, i
, :=J,.~
I .
I
/I
1/
'/I
II
II
II
'I
1\
\ )\
..... :--.. /.1'.,
'~ j7 /~'
'R/\/oU'e ",",I ,'f'
Jt
)~
,~
o
I
'fYO
scale in feet
IOD 101)
I
.-'1611
(~
Note: ~i'l-18B mt shown
Source: Final Fast-Track na:mi.al Investigation Feasibility StOOy,
Nay Ie, 1984, prepared by Qj~1 Hill -
I
,,+
-------
FIGURE 3
PROCESS FLOW DIAGRAM RECOMMENDED PRETREATNENT SYSTEM
,
METALS REMOVAL
A.
,
~A.JICt; ~EMOVAL
A.
LIME
POLYMER
CLARI1=IER
EaU4L'ZA T,O#.J
(USE eX1571.J; Z2WKAGE)
"'
M'XED
MEDIA.
FILTRd TJaJ
DlP,TY FILTER
84C!KWA 51-/
STQl?AGE.
DEWA TIERED
SLUDGE TO
CLASS I
asA?S4L SITE.
CAUSTIC
VACUtA\If
FILTER
EGlUd..LIZA TIOAJ
JJEUTRALIIA 1/OAJ
FILTER.
BAC!KWA5H
CAR8QIJ
AD'3ORPT1O#J
COlJT.6.C.T
VESSELS
.
CAR60AJ
TRAAlSFEIZ
VESSEL5
MIY.ED MEOlA
FILTRATlOAJ
JJOTE.5 :
,. S7REAMA I5FP.DM WELLS OW-.tJ OW-2"OW-4l.IW-1 A#JD
mE FREAJeH ~/AJ. AVERAGE FLUW 15 E.,.PE.C.Tt::.D TO 61:
20 GPM. DE5tGAJ FLOW 15 50 GPM.
Z. STREAM 815 T=ROM MID-CAAJYOAJ WELLS IW-2 ~ nv. 3.
AVERAGE. FI.DW 15 EXPECTED TO 8/::. 40t3PM. DES/GAl
FLOW 15 80 GPM.
3. TP'EATED GROUAlDWA7ER WILL 6E HAULED
AJJO OJt9CHARGED TO A POTW.
4. rREATA8ILITY'STUDIES ARE REQUIRED TO COAlFIRM
SY5TEM ca.JF/,GUR~TIOA.J ~ OEFIA-'E DE5/GAl RWAMETER5. .
C.L EAAl
84CKWA51-1
t EFFLUEAJT
sroRAGE.
,
'..
Source: ,inal Fast-Trac~ Remedial I~vestigation feasibili~y Study, ~ay :8, :984, prepared by
CH2N Hill
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RESPONSIVENESS SUMMARY
STRINGFELLOW SITE
Riverside, California
I. INTRODUCTION
This responsiveness summary addresses the comments made
by governmental agencies and the public concerning the Fast
Track Remedial Investigation/Feasibility Study (Fast Track)
report for the Stringfellow Site, Riverside, California,
issued May 18, 1984.
REVIEW PROCESS
The final draft and the final report were available for
public review and comment to three Riverside County public
libraries. The final report was also distributed to public
libraries in Los Angeles and Orange County; availability of
the report was noticed in the Los Angeles Times, the Riverside
Press Enterprise, and the Santa Ana Register.
Copies of both reports were mailed directly to local
agencies, the Stringfellow Advisory Committee (SAC), and counsel
to selected potentially responsible parties. Written comments
on the final draft were received from the Orange County
Water District, the California Department of Health Services
(DOHS), the California Air Resources Board, and the California
Department of Transportation. Comments on the final draft
were incorporated into the final report.
Written comments on the final report were received from
the California Department of Health Services, the Santa Ana
Regional Water Quality Control Board, the Santa Ana Watershed
Project Authority (SAWPA), the U.S. Army Corps of Engineers,
and counsel to the potentially responsible parties. Comments
on the final report and EPA's responses are summarized below.
A list of all comments is attached. Copies of comments
received on the final draft and the final report are available
at EPA-Region 9 and EPA-Headquarters.
OBJECTIVES OF THE FAST TRACK
Several commentors seem to confuse the objectives and
scope of the Fast Track study with those of the full-scale
Remedial Investigation/Feasibility Study (RI/FS) which is
being conducted by DOHS, and which will address the entire
spectrum of problems associated with the Stringfellow site.
The Fast Track is a focused effort designed to address
specific aspects of the overall problem within a shorter time
J
-------
- 2 -
than the full-scale RIfFS. The recommendations developed in
the Fast Track study are to be implemented for the interim
period prior to completion of the full-scale RIfFS and con-
struction of the final remedy.
As stated in the report, the primary objectives of the
Fast Track study are to:
o Develop data on downgradient migration of contamination
to assess public health endangerment.
o Develop criteria for mid-canyon interception of contaminated
groundwater as a means of mitigating identified public
health endangerment.
o Identify and evaluate alternative methods for management
and disposal of contaminated water collected from onsite
and down-gradient wells.
o Develop a plan for implementation of the most cost-effective
alternative for management and disposal of contaminated
water collected from onsite and downgradient wells.
Other aspects of assessing hazards and determining cost
effective remedial actions are included within the scope of
the full-scale RIfFS.
r
,
II. COMMENTS AND RESPONSES
GROUNDWATER FLOW IN THE BEDROCK
The commentors contend that bedrock could be a pathway
for flow of groundwater and transport of contaminants. The
Agency agrees that contaminants ~ould be moving through
fractures and weathered zones in the bedrock. However, the
existing database is insufficient to examine this possibility.
Definition of the bedrock hydrogeology represents a sizeable
and time consuming data-collection effort. Consequently,
this could not have been included within the scope of the
Fast Track study. As was stated in the Fast Track report,
these data will be collected during the RIfFS.
GROUNDWATER QUALITY
The commentors have various concerns regarding the ground-
water quality database used in conducting the Fast Track
study. In general, these concerns result from a failure to
recognize the purposes of the database and the distinctions
between the Fast Track study and the RIfFS. The groundwater
database has been valuable in (a) increasing the Agency's
understanding of the areal extent of contamination, (b)
assessing the endangerment t9 the public, (c) designing the
RIfFS, and (d) designing interim remedial facilities.
Considerably more data must be collected during the RIfFS to
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- 3 -
define the areal and vertical extent of contamination and
appropriate long-term remedies.
The commentors state that there has been an incomplete
and inadequate analysis and evaluation of all the data. The
Fast Track report did not provide an exhaustive review of
all data collected (i.e., greater than 30,000 data points),
because it was designed to be limited in scope and to result
in the selection of interim remedies. The conclusions reached
by the Fast Track report are supported by the groundwater
quality database. Substantially more data gathering and
analysis will be conducted in the full-scale RI/FS for selection
of the cost-effective final remedies.
The commentors state that no analysis of pre-1983 data
was performed. These data are limited in comparison to the
extensive data that have been collected in 1983, particularly
for organics and metals. The pre-1983 data, though not
exhaustively reviewed in the Fast Track report, support the
conclusions of the report.
The commentors state that the groundwater data collected
did not provide all the necessary data for designing the recom-
mended pretreatment facilities. Samples collected during 1983
were analyzed for a broad spectrum of constituents (approximately
140 parameters per sampling) with major emphasis on potential
adverse health effects. Many of these same data are useful
in designing pretreatment facilities recommended by the Fast
Track report. Additional data, such as TOC, COD, BOD, and
TSS, are necessary for pretreatment design purposes, and are
currently being collected as part of the treatability study
that is recommended by the Fast Track report. .
The commentors state that the analytical scatter and
inconsistencies in the data negated its usefulness. Sampling
from April through November 1983 resulted in over 30,000 pieces
of data. Considerable efforts were expended by the Agency to
obtain these data using standardized sampling and analytical
procedures. The overall sampling results demonstrate consistent
patterns and strongly support the recommendations of the
Fast Track report.
MID-CANYON HYDROGEOLOGY
The commentors state that considerable uncertainty still
exists regarding the hydrogeology of the alluvial aquifer in
Pyrite Canyon. Uncertainty does exist and will be addressed
in the RI/FS; however, the following is certain:
o A large volume of contaminated groundwater exists upgradient
of.mid-canyon; and
o The direction of groundwater movement is down-canyon,
toward Glen Avon.
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- 4-
Therefore, interception at mid-canyon of contaminated ground-
water will reduce the threat to groundwater supplies downgradient
of Stringfellow.
The commentors criticize the estimate of groundwater
velocity as based on only a few permeability measurements in
a heterogeneous aquifer. The Agency agrees that it would be
better to have more permeability estimates. However, the
potential threat to downgradient groundwater supplies dictates
that a decision be based on existing data. It is reasonable
to estimate the average groundwater velocity based on the
average of the measured permeabilities.
The commentors express concern regarding the scatter in
the permeability data. A wide range in permeabilities is
typical of heterogeneous alluvial deposits. Clay strata or
cemented alluvium would have a low permeability while sand
or gravel strata would haye a high permeability. If high
permeability sand and gravel deposits are interconnected,
the velocity of some contaminated water would be faster than
the average velocity estimated in the Fast Track report.
The commentors express concern regarding the assumption
that trichlorethene (TCE) and chloroform would move at the
same rate as groundwater. The mobility of organic contaminants
may be affected by physical, chemical or biological processes.
However, no data exist to assess the effects, if any, of these
processes in Pyrite Canyon. Experience at other sites through-
out the u.S. has conclusively demonstrated the mobility of TCE
in groundwater. When assessing the potential threat to public
health, it is necessary to make conservative assumptions;
consequently it is reasonable to assume that constituents such
as TCE and chloroform move at the same rate as groundwater.
,
The commentors criticize the aquifer testing program in
the Fast Track study, stating that only step drawdown tests
were used. This is incorrect. The Fast Track study. included
a 24-hour, constant-discharge aquifer test as well as four
step-drawdown tests. The 24-hour test was the longest aquifer
test performed in the mid-canyon. The Fast Track report recom-
mends that further testing be performed in the mid-canyon to
refine determinations of the long-term response to pumping.
Such testing has recently been performed in the mid-canyon
using MW-l9, IW-2, and IW-3.
The commentors state that it has not been demonstrated
that the interceptor wells will fully capture the contaminants
moving through the mid-canyon. The Agency believes that
additional hydrogeologic testing will be required to demonstrate
that the mid-canyon groundwater interception system fully
captures contaminants moving through mid-canyon. However,
it is certain that pumping existing interceptor wells will
remove contaminated groundwater that would otherwise move
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- 5 -
downgradient toward Glen Avon. Removal of these contaminants
will significantly reduce the threat posed to groundwater
supplies. In view of this threat, installation of an operational
interception system should not await the resolution of all
uncertainties regarding groundwater movement in the canyon.
ALTERNATIVE METHODS OF CONTROLLING CONTAMINANT MIGRATION
The commentors state that there may be better ways of
controlling the groundwater than by mid-canyon extraction.
The Agency agrees that means other than mid-canyon extraction
have merit for controlling migration of groundwater contaminants.
Three pump barrel wells (UW-l, UW-2, and UW-3) and a springbox
have been installed upgradient of the site to intercept
additional uncontaminated groundwater and to prevent it from
conveying contaminants from the site. The anticipated effect
of pumping these wells will be a reduction in the current
pumping requirements from the onsite wells. The RIjFS
contractor is presently developing an operation plan for the
pump barrel wells. Upgradient interception of uncontaminated
water is also a primary objective of the RIjFS.
The commentors urge that as much contaminated water as
possible be extracted from the site in order to remove water
with the highest levels of contamination. EPA agrees with
this approach. The Fast Track report recommends continuing
the present onsite pumping program at wells OW-I, OW-2,
OW-4, IW-l and the French Drain. In addition, pumping at
mid-canyon is .recommended in order to capture contaminants
which have already migrated beyond the influence of onsite
wells.
The commentors argue that surface water diversion was
not considered as an alternative remedial measure. Infiltration
of surface water is a potential source of recharge of both
contaminated and uncontaminated water throughout Pyrite
Canyon. Diversion of surface runoff may be a component of
the final remedy to be employed at the site. To determine
the need for and to design additional surface water diversion
structures extending down-canyon requires knowledge of the
precipitation characteristics of the site itself and a better
definition of the site water budget. These data do not
exist and their collection would require an extensive hydrologic
monitoring program which will be performed during the RIjFS.
CAPTURE OF DOWNGRADIENT CONTAMINANTS
The commentors point out that the mid-canyon interceptor
well system will not reverse contaminant flow or remove con-
taminants that have already migrated past this mid-canyon area.
The Fast Track report definitively acknowledges this problem.
However, as indicated above, the objectives of the Fast
Track study are limited. The RIjFS will investigate the
extent of contaminant migration past the mid-canyon area and
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- 6 -
the need for remedies. Because the bulk of the known contam-
ination is still upgradient of the mid-canyon, interception
of groundwater from the mid-canyon will prevent the further
deterioration of groundwater quality past this area.
PRETREATMENT STANDARDS
The cornrnentors have questioned the need to pretreat
extracted groundwater prior to discharge to a regional inter-
ceptor. As described in the Fast Track report, each of the
three candidate Publicly Owned Treatment Works (POTW) systems
for disposal of Stringfellow water has established quality
limitations for discharges into its system. Untreated String-
fellow groundwater exceeds the quality limitations of all
three of the systems and could not be discharged to anyone
without pretreatment. Discussions between EPA and Santa Ana
Watershed Project Authority (SAWPA), County Sanitation Districts
of Orange County (CSDOC), Chino Basin Municipal Water District
(CBMWD), and Los Angeles County Sanitation Districts (LACSD)
have confirmed this determination.
The cornrnentors have challenged the appropriateness of
the proposed pretreatment standards and suggested that accept-
able water quality requirements for discharge of extracted
groundwater to regional interceptors be obtained or negotiated.
As described in the Fast Track report, the operator of a
regional interceptor (SAWPA or CBMWD, in this case) must
obtain concurrence from the receptor POTW (CSDOC or LACSD)
for all industrial wastes admitted into its system. The
POTW may deny a permit for discharge that it believes could
adversely affect the operation of its treatment plant, or
which could affect compliance with its NPDES permit require-
ments. The burden of establishing that no adverse effects
will result falls upon the waste generator. It was with
these considerations in mind, and after discussing the matter
with representatives of SAWPA, CSDOC, CBMWD, and LACSD, that
EPA adopted the approach presented in the Fast Track report
for developing the proposed pretreatment standards.
l
I
The cornrnentors also suggest the EPA did not contact SAWPA
to discuss the requirements for discharge of Stringfellow
water into the SARI line. This is not correct. From the
start of the Fast Track study in September 1983, EPA has
worked with SAWPA to define a mutually satisfactory basis
for discharging Stringfellow water into the SAWPA system.
EVALUATION OF ALTERNATIVES
The cornrnentors state that the Fast Track study should
have relied more heavily upon a matrix analysis for the
comparison of alternatives. The Fast Track study employed
methods of analysis which are consistent with the intent of
the NCP and EPA guidance. Several alternatives discussed and
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not recommended by the Fast Track report, as well as combinations
of portions of these alternatives, remain under consideration
in the full-scale RI/FS. Given the objectives and limited
scope of the Fast Track study, these alternatives were not
appropriate for further consideration as interim measures.
The commentors state that solar evaporation and air
stripping should have been more thoroughly evaluated in the
Fast Track study. The primary reason for eliminating solar
evaporation during the initial screening process was that no
available, suitable land area was identified. Establishment
of surface impoundments for solar evaporation either in Pyrite
Canyon or else where in the vicinity was judged to be unaccept-
able to the surrounding community. It should be noted that
the existence of the Stringfellow site as an uncontrolled
hazardous waste site is due to a failed attempt at solar
evaporation. A second attempt at onsite solar evaporation
was anticipated to be contested by the comunity and local
agencies and could preclude implementation of this alternative
in the three to five year interim period of the full-scale
RI/FS and the construction of the final remedy.
Air stripping was rejected as a suitable pretreatment
operation primarily because it is capable of removing only
volatile organic compounds (VOC). It is not effective for
removing acid or base-neutral extractable compounds, which
are also present in the Stringfellow groundwater. It was
also rejected because of its potential for VOC emissions.
The length of time needed to study the potential VOC emission
was beyond the scope of the Fast Track study and will be
included in the RI/FS.
ADDITIONAL STUDIES
The commentors assert that the Fast Track study is
deficient due to the lack of treatability work and long-term
pump testing of the aquifer in the mid-canyon region. Both
of these studies were recommended in the Fast Track report as
the next required activities and have been conducted.
TRICHLOROETHENE
A commentor stated that the organic chemical ~trichloro-
ethene" referred to in the Fast Track report does not exist.
The commentor expresses a familiarity with "trichloroethylene"
and apparently is unaware ,that the terms, "trichloroethene"
and "trichloroethylene" are synonomous. The proper name for
the compound in question, C2HCl3, under the "Geneva system"
adopted by the International Congress held at Geneva, Switzer-
land, in 1892, is trichloroethene. This system, which covers
the primary phases of the nomenclature of organic chemistry,
has been repeatedly reaffirmed and extended since its inception.
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LACK OF ADHERENCE TO THE WORK PLAN
. The commentors state that the primary objectives of the
Fast Track study were not accomplished and that discrepancies
between the work plan and the work as presented in the final
report compromised the quality of the study. Although certain
elements of the scope of work were not performed as originally
described, the primary objectives of the work plan have been
fully met. Changes were made according to the exigencies of
the work as it progressed. In some cases, items of the work
plan became impossible to perform within the scope of the
project. for example, negotiations with SAWPA could not be
completed before completion of the Fast Track study and are
continuing with EPA and DOHS.
PAST REPORTS
The commentors state that the Fast Track study failed to
refer to past reports and data. The Fast Track study reviewed
and, as appropriate, utilized previously generated reports
and data on the Stringfellow site. Previous studies, such
as those conducted by J.M. Montgomery, Consulting Engineers,
Inc., while providing useful insight, were often out-of-date
or did not consider information now available. For example,
in a 1981 report, J.M. Montgomery recommended discharge to
the SARI line, but assumed that an extension line would be
constructed to within one mile of the site, allowing a direct
connection from an onsite treatment plant to the extension
line. In fact, this extension line has not been built.
t
I
OTHER AGENCIES' COMMENTS
Comments received from the .Hazardous Materials Laboratory
Section of California Department of Health Services were
detailed and largely consisted of editorial suggestions.
Many of these have merit, but overall do not alter the con-
clusions presented in the Fast Track report.
The Santa Ana Regional Water Quality Control Board, Cali-
fornia Department of Transportation, and California Air Resources
Board have each concurred in the recommendations of the Fast
Track report. The California Department of Transportation
stressed that adequate consideration be given to potential
hazards associated with truck hauling of untreated hazardous
wastes. The California Air Resources Board noted that additional
study would be required if air stripping were to be considered
further.
Comments received from the U. S. Army Corps of Engineers
generally cover the same topics discussed by other commentors.
Responses previously presented in this document address these
comments. .
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III. CONCLUSION
The comments received were helpful, but were not of a
nature to cause a revision in the findings of the study.
The Santa Ana Watershed Project Authority (SAWPA) has
submitted a proposal to DOHS under which SAWPA would implement
the alternative recommended in the Fast Track report. SAWPA
is one of the sewerage authorities recommended by the Fast
Track report for disposal of the pretreated groundwater. In
anticipation of EPA's approval of the remedy recommended by
the Fast Track report, DOHS has entered into the first phase
of a contract with SAWPA for contractor procurement. Following
this first phase of the overall program, DOHS plans to enter
into additional contracts with SAWPA for contract management,
design, construction and operation of the pretreatment plant.
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