United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R10-86/008
•September 1986
SEP A
Superfund
Record of Decision
-------
TECHNICAL REPORT DATA
(P1H$. rnd bUtNctIO'U 011 tht rtvtnt /HI"'t co,""ltti"l)
..I'ORT NO. 12. 3. RECIPIEIIIT"S ACCESSION NO.
~:PA/ROD/R10-86/008
.. TITLI AND SUITITLI 5. AEPORT OATE
SUPERFUND RECORD OF DECISION C::""''\+-ember 1 2 1986
United Chrome, OR I. PERFORMING ORGANIZATION COOE
,. AUTHOR'SI 8. PERFORMING ORGANIZATION REPORT NO
9. PEAFORMING ORGANIZATION NAME ANO AOORESS 10. PAOGRAM ELEMENT NO.
". CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME ANO AOORESS 13. TyPE OF REPOAT ANO PERIOO COVEFlEO
U.S. Environmental Protection Agency !:';n~l ROD Q~nnrl-
401 M Street, S.w. 14. SPONSOAING AGENCY COOE
washington, D.C. 20460 800/00
15. SU"LEMINTAAY NOTES
11. A8STRACT
The United Chrome Products (UCP) site is a former industrial hard chrome plating
facility located in Corvallis, Oregon. UCP began electroplating operations in 1956.
. .Between 1956 and 1915 an onsite dry well was used to dispose of floor drippings,
rNashings, and product rinsate collected in a sump within the building. The liquids werE
reportedly neutralized with sodium hydroxide and/or soda ash prior to disposal. use of
the dry w~ll was discontinued in 1915. .~s a result of the immediate removal action, to
stabil ize the site, all hazardous substance source materials have been removed with the
exception of residual sludges in the bottom of the plating tanks. However, there is
considerable chromium contamination in the soil beneath and around the building and in
the upper and lower aquifers as a result of leaching from the dry well and plating tank
The selected remedial action for t!1is site includes: installation of approximately
15 shallow wells in the upper confined ground water zone; installation of 5 deep we 11 s
in the lower confined production aquifer; limi ted excavation of contaminated soil and
offsite disposal; installation of onsite treatment equipment (chemical reduction and
'precipitation) to remove chromium from extracted ground water; construction of t'NO
percolation basins to flush soil; and installation of culverts. Estimated capital cos~
for the selected remedial alternative is $1,580,000 and the annual O&M costs are
approximately $261,000.
17. I(EY WOROS ANO OOCUMENT ANAL VSIS
a. oesC,..,TORS b.IOENTIFIEFILSIOPEN ENOEO.TERMS C. COSA TI Fleld;Croup
Record of Decision
United Chrome, OR
Contaminated Media: gw, soil
Key contaminants: chromium
18. 0lSTRI8UTION STATEMENT 19. SEcuRITY CLASS, Tltls Rtpon/ 21. NO. OF ;:>AGeS
None 62
20. SECURITY CLASS {Tltis POltl 22. PAICE
Non@
I!'. ,...'" 2220-1 (R... 4-71)
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SITE
Record of Decision
Remedial Alternative Selection
~
United Chrome ProQucts. Corvallis. Oregon
~
DOCUMENTS REVIEWED
-
The following documents describing the analysis of the
cost-effectiveness of remedial alternatives for the United Chrome Products
Site provide the primary basis for this decision:
.
Final Remedial Investigation Report. Volumes 1 and 2.
July 26. 1985.
Public Comment Feasibility Study. August 199 1985.
.
.
Summary of Remedial Alternative Selection.
Responsiveness Summary.
.
DESCRIPTION OF SELECTED REMEDY
.
Installation of approximately 15 shallow wells (15 to 20 feet) to
extract chromium-contaminated groundwater in the upper unconfined
groundwater zone.
.
Installation of approximately 5 deep wells (35 to 40 feet) to
extract chrom1um-contaminated groundwater in the lower confined.
production aquifer.
Installation of on-site treatment equipment (chemical reduction
and precipitation) to remove chromium contamination from extracted
groundwater prior to discharge to Muddy Creek or city of Corvallis
Wastewater Treatment Facility.
.
.
Construction of two percolation basins in the areas of the former
dry well and plating tanks to flush the contaminated soil above
the shallow groundwater table. Approximately 350 tons of
contaminated soil excavated during the construction of these
basins would be disposed of at a permitted land disposal facility.
Installation of culverts in the adjacent open drainage ditch to
isolate the surface drainage system from the inflow of
contaminated surface water and groundwater from the site.
-------
2
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 foregoing Description of
Selected Remedy at the United Chrome Products site is cost-effective and
provides adequate protection of public health, welfare, and the
environment. The state of Oregon has been consulted and agrees with the
approved remedy. In addition, the action will require future operation and
maintenance 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 for a period not to exceed one year.
All off-site disposal shall be in compliance with the policies stated
; n the Procedure for Pl anni ng and. Impl ementi ng Off-Si te Response Acti ons
(Federal Register, Vol. 50 Number 214, November 5, 1985, pages 45933 -
45937). 1n add1tion, I have determined that the action being taken is
appropriate when balanced agai.nst the availability of Trust Fund monies for
use at other sites. The implementation of the selected remedy is more cost.
effective than other remedial actions and is necessary to protect public
health, welfare, and the environment.
~-\Z-v~
-------
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
UNITED CHROME PRODUCTS
SITE LOCATION AND DESCRIPTION
The United Chrome Products (UCP) site is aO former industrial hard
chrome plating facility located at 2000 Airport Road in the Airport Research
Industrial Park complex. The airport is located approximately 3.5 miles
south of the city of Corvallis (1980 population, 42,000) in Benton County,
Oregon. The UCP site consists of a single building on approximately 1.5
acres of level ground and is bounded by the Corvallis Airport. All of the
property around the site including UCP is owned by the city of Corvallis
(Figure 1). -
Surface water runoff from the site drains into an open ditch along the
northern edge of the facility. This ditch drains into Dry Creek,
approximately 1.5 miles to the east. Dry Creek drains into the West Fork of
the Boonevil1e Slough and finally into the Wil1amette River. The Willamette
River is a primary source of drinking water for the city of Corvallis.
The local subsurface environment at the UCP site is characterized by
two saturated zones. The upper unconfined zone consists primarily of clayey
silt alluvium with a saturated thickness of 15 to 18 feet during winter
months and decreasing during the summer. During the winter the saturated
zone often reaches the ground surface. The lower confined aquifer ranges at
depths from 29 to 45 feet below the ground surface. This aquifer provides
water for the airport complex and nearby businesses and residences. There
is a silty clay unit separating the two saturated zones at a depth of about
17 to 21 feet below ground surface.
SITE HISTORY
UCP began electroplating operations in 1956. The dry well disposal pit
was created in the same year by removing approximately 3 feet of native soil
in the area west of the building and backfilling with sand and gravel.
Between 1956 and 197~ the dry well was reportedly used to dispose only of
floor drippings, washings, and product rinsate collected in a sump within
the building. The liquids were reportedly neutralized with sodium hydroxide
and/or soda ash prior to disposal in the dry well. Quantities of waste
discharged are unknown, but were estimated by the facility operator to be
approximately 1,OUO gallons per year. In 1975, use of the dry well was
reportedly stopped. The amount and disposition of wastes produced since
then is unknown. .
The specific composition of wastes discharged to the dry well are also
unknown; however, the nature of the facility indicates that one or more of
. the following general waste streams may have been involved:
.
Spent plating bath solutions
Spent stripping and cleaning bath solutions
Sludges from the bottom of plating baths
.
-------
.
-' ,.. "
-1
61
.- :
...~
- ---j
,....
. .1.
I . ~.. ,......-
., .......1.....-
-. .
..
. .
. "".-,
. .'.~ 8(10.....111.... " .
IS.I.. 1
I
t
-AL' 1 "':000
S... .. 0 .
I .",L
o
:oac
:aaa
lOIII
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o(Q)
..cca
IIJaD
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----
. ;;:-. (CT
1 ClIO
-
.
- --
FIGURE 1 AI
LOCATION ~DUCTS
UNITED C~~~r~REGON
CORY I"\Wo O4ROME FS
-------
The facility operator has stated that the contents of plating bath
tanks were not disposed of in the dry well. Instead, plating solutions were
recycled by allowing impurities to settlep and adding additional chromium as
neeaed to rejuvenate the bath. In 19829 accumulated sludges were removed
from the tanks and disposed of under Oregon Department of Environmental
Quality (ODEQ) guidance.
In November 1984, UCP announced that it would shut down and cease all
operations by early 1985. In May 1985, the equipment and contents of the
building were sold at auction. The building is currently vacant. The city
of Corvallis has indicated that it presently has no plans for alternative
use of the site area and building, or for demolition of the facility.
An immediate removal action was initiated in July 1985 to stabilize the
site after the company vacated the building. An eight-foot chain link fence
was installed around the perimeter of the site and approximately 6,300 .
gallons of spent plating solution and 114 drums and containers were
removed. These activities were completed in October 1985. A chronological
list of the investigations conducted at UCP is presented in Table 1.
CURRENT SITE STATUS
As a result of the immediate removal action completed in October 1985,
all hazardous substance source materials have been removed from the site
with the exception of the residual sludges in the bottom of the plating
tanks. However, there is still considerable chromium contamination in the
soil beneath and around the building and in both the upper and lower
aquifers, as a result of leaching from the dry well and plating tanks
(Figure 2). '
The estimated lateral extent of contamination in the upper and lower
zones are shown in Figures 3 and 4 respectively. The total volume of
contaminated groundwater in both zones is estimated to be 2.4 million
gallons. The chromium concentrations (total chromium) in the upper zone are
as high as 1.5 per cent near the plating tanks with concentrations in the
surrounding monitoring wells ranging from 142 to 689 milligrams per liter
(mg/1). Concentratio"s in the lower zone are generally an order of
magnitude lower; however, the primary. drinking water standard of 0.05 mg/1
has been exceeded in numerous deep well samples.
The nearest potential receptors for the contaminated groundwater are
the city of Corvallis' two production wells approximately 3,000 feet
downgradient from the UCP site. These wells serve the airport complex. In
addition, the nearby open drainage ditch continues to receive contaminated
-------
TABLE 1
INVESTIGATIONS AT UNITED CHROME PRODUCTS SITE
PrU1d.p81
Inve.uqatot
Onqon DeQartPDt
of Envir0ft88ntal
QUal1ty (DEQ)
O~
D~
EllA (IIZ)
D~
OA (EU)
OA (~E)
EPA (CorvalliS
Environmental
Research Lab)
OA (EU)
o~-
OA (~E)
EPA (CorvalliS
Environmental
Reseucb tAb)
De t. of
Inve.t1qaUon
Nov. 1982
Dee:. 1982
JaD. 1983
JuDil 1983
JuD. 1983
July 1983
JaD. 1984
Feb. 1984
Feb. 1984
OCt. 1984
Dec. 1984-
Feb. 1985
Dec. 1984
Puroo.e of Investiqation
SUIIDUV of Resul ts
Sall91. 2 Cit.y of CorvalliS No evic1ence of c:hromiWII
v.l1. aDd 2 do88.t1c v.ll. contaminat.ioD «0.002 mq/L
total Cr)
Supl. surface dU~q.
by. c1r7 well
Supl. secU._Dt 10
Boon..ille Slouqb
SU;le tJD1te4 ChroM
cU. tcb sec11MDt
SU;1. Uft1t.e4 CbR88 4rT
.11 se41MDt.
Install aDd supl. 4
sballow vell. 1D 4ry .11
ana
tuta11 ad suple 5 d88p
vells UCNDd per188t8r of
facU1t.y
SUp1. local dra1D8q8
n.twork
SU;le ruDO!! aDd .ludq.
by dZT _11
Hanrd nnld.nq .yst..
scor. of .u.
Re.uple existinq 8QGi-
torinq weUs
Aquatic aDd terr~trial
bioassays on soil, sedi-
Mnt, qrounc!vat.er, and
surface vater
Reconstruct 3 c1eep wells,
lnstall one ac1dit1onal
shaUow vell north of
tb8 slt.
Supl. runoff froa dZT
vell aDd Unit.ed Cbraa.
d1tcb
Reae41al in.,e.uqaUoD
AquatlC aDd terrest.rial
b10assays OD qrounc1vater
fr08 vells const.ructed
dur1ftq R1
El.vated levels of chro-
111U8 (4.2 mq/L total Cr)
Elevated l.vels of chro-
111U8 (0.06 mq/L total Cr)
Elevat.ed levels of cbro-
111U8 (410 mq/kq total Cr)
21,000 89/tq t.otal Cr
UQ to 3,619 119/1. cU.ssolved
Cr 1A ~UDdwat.er: soU
claPU1ed as b,uudoUS
vaste
Up to 3.0 aqlL d1Sso1ved
Cr 10 grOUDdWater
UQ to 10.5 8q/L cU..solved
Cr 1ft surface vater and
4.3 8q/L t.otal Cr 10
sed188Dt. leacbat.
n.vated lev.ls of Cr,
operator orc1end t.o AIIOV.
.ludqe
HIlS scon . 31.7
Chroll1W1. concentraUon ln
2 de.Q veUs i.ncreased s1q-
nlficaDt.ly (to 29.9 mq/L
and 24.8 mq/L comparec1
with June 1983 results) .
Not releasec1
New shallow vell contami-
nated (302 mq/L total Cr)
Elevated levels of Cr re-
sult.1nq 10 a c:iv11 ~nalty
aqainst faCility operator
.Discussed in Volume I of 2-
volume Remedial Invest.1qa-
tiOD Rep)tt
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:::::::::::::::: :u' .N' .C' .ON'" 'fl' 'N' '£'D" '''ON'''' E..::: :::::: ::::::: :::: ::::::::::::: ::: :::::::::::::: ::: :::::::::::::::::::::::::::::::::::.::: :j~::::::::::::
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-------
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SCALE
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LEGEND
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FIGURE 3
-------
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-------
ENFORCEMENT
On July 13, 1983, ODEQ sent a Notice of Violation (NOV) to UCP citing
unlawful disposal of hazaraous waste and unpermitted discharge of wastes
into public waters. This NOV directed UCP to remove the chrome sludge from
the dry well area and dispose of it in accordance with state regulations.
A subsequent inspection by ODEQ on July 22, 1983, revealed that no
cleanup action had been taken by UCP. In response, ODEQ issued a second NOV
on July 27, 1983, requiring UCP to register as a hazardous waste generator
and again directing the company to properly dispose of the chrome sludge.
By the September 7,1983, inspection by ODEQ, the sludge had been removed'
from the dry well area by the company and placed in drums which were later
disposed of at a RCRA-permitted land disposal facility. .
On January 18, 1984, ODEQ sent a letter to UCP summarizing the results
of EPA's 1983 field investigation at the site and directing the company to
evaluate its operating practices and to make all necessary improvements by
July 15, 1984. In response, UCP retained a consultant to evaluate its
operation, and on June 22, 1984, submitted a proposal to ODEQ for upgrading
the company's chrome handling practices. Final design was to have been
submitted by August 30, 1984, and construction of containment faci1ities
'completed by October 15, 1984.
An October 4, 1984, inspection by ODEQ revealed that UCP was still
allowing contaminated runoff to discharge into public waters. On
January 10, 1985, ODEQ issued a Notice of Assessment of Civil Penalties for
continued violations and for UCP failing to initiate any improvements to its
operation. The company appealed this order but in early 1985 ceased
operation. In May of that year it auctioned off the equipment to pay a
portion of some $350,000.in outstanding debts. While the company did not
declare bankruptcy, there are cle~rly no funds available from the company to
.pay for any of the rem$dial activities at the site.
The UCP building and property are owned by the city of Corvallis.
Because the city was not the operator at the site, no enforcement action is
being considered at this time. The reauthorization of Superfund will likely
include some changes from the present law regarding publicly-owned sites.
EPA will reevaluate possible enforcement activities after reauthorization.
ALTERNATIVES EVALUATION
There were three primary public health and environmental objectives
developed for the UCP site:
.
Adequately protect the public against contact with and ingestion
of contaminated groundwater.
Mimimize threats from and adequately protect the environment
against the spread of contaminated groundwater.
.
.
Adequately protect the public against contact with and ingestion
-------
The Feasibility Study identified response actions and remedial
technologies which consist of source control measures, migration control
measures, and other measures. These response actions and remedial
technologies are listed in Table 2.
These response actions and remedial technologies were then assembled
into twelve potential remedial action alternatives. These alternatives are
listed in Table 3. A brief description of each alternative is presented
below:
Alternative 1:
No Action
By taking no action to clean up the site, contaminants in the soil and
the unconfined groundwater zone will continue to migrate from the site
and cont~minate the confined aquifer. .
Continued migration in the unconfined groundwater zone will result in
the broadening of the contaminant plume above the confining clay
bedc~pr1marily in the direction of the flow gradient (northeast).
There are two primary concerns with such an occurrence. First, the
confining clay bed is not well defined outside the immediate site
area. Continuity, thickness, and permeabl1ity of the confining clay
bed both within and without the investigation area may vary
significantly from. that ~efined during the remedial investigation.
Since confining layer continuity, thickness, and permeability determine
the rate that contaminants will leak to the aquifer, potential exists
for significantly higher leakage rates outside the site area.
Second, analysis of water table contours suggests that there may be
. significant groundwater discharge from the upper unconfined zone into
the local drainage ditch system. The water table seasonally rises
above the flow 11n8 of the ditch system. The significance of this
discharge as a source of surface water contamination has not been.
established. Elevated total chromium concentrations (up to 55 mg/l)
have been monitored in the drainageways. However, the source of this
contamination has not been confirmed.
There are two recognized sources of surface water contamination, other
than the potential groundwater discharge:
.
Roof and site drainage from the United Chrome building area. and
Contaminated sediment in the drainageways--probably from the
foregoing.
.
The relative significance of groundwater discharge as a source of
surface water contamination in unknown, but continued migration of
-------
TABLE 2
RESPONSE ACTIONS AND TECHNOLOGIES
SOURCE CONTROL MEASURES
Excavation of contaminated soils
. 0 Offsite disposal
o Onsite landfill disposal
containment
o Capping .
o Vertical barriers
o Bottom barriers
o Stabilization/solidification
Tr.atm8nt
. 0
o
o
Soil flushing
Chemical reduction
Biological treatment
MIGRATION CON'rROL MEASURES
containment.
Groundwat.er extraction
. . 0 Disposal of extracted groundwater
Surface stream discharge
Discharge to Corvallis POTW
Disposal to a permitted facility
Aquifer recharge
Land application
Treatment
o
o
In situ treatment
Treatment of extracted groundwater
OTHER MEASURES
Provide alternative drinking water supply
o Extend city water distribution system
-------
CCIftMINAIID sea:
UNCONfINIDZONI
GIOUNOWAIU
CONMIO AQUIFlI
ALt'IIIWM' (
MTllNAlM2
MIllNAlMI I Sot I 0If8f8 I
~ 0iIDQIGI
. M.JI8WM'
AUl8lAJMI I PI:Ifta8 ~tI
StJ! ~
~. I SOil \ 0IIIit8
~1G8, 0itDCCI
M.JI8WM 7
AUl8WMI ( Sol \ 0IIIit8 I
~1iCII. 0iIDQIGI
ALftIMAINI'
I
~"'If~
Waf8t SuccI\'
r
No ACtIOn
r=:.1
~-l
!
Ie-I
leer I
I-=-I
MuOCJV
CI88M
~
1
1 I
\ =-~- --
GIo'~. ~
&nai:nonI C/,, J
T~f o.~
~l
PrOVIde "'fernaf1\18 !
WOf., ~ .
=-1
M1I8WM t2
~ &eCl\l- OfbIf. OICICd Gtounawot.. MudCI\I "'0\1'08
OfICnI Sol f/ear &nacf8O E.,-rQCTICnI CrMII :'1Ien"QT.""
R\dtWIQ RUtf'I waf8f f/eaTmenf O'SCf\Ofge Nor.. SugaIV
IIaIftaI ~ 0IIIit8 0i1ClCG Gt~ MudCI\I GtQuroOooOt.. MudCI\I
QllantSOil Treat &nacf8CI ~nonI Cr8811 E .,-rQCf1CI'Il Cr....
~ Ru!f'I 1NCf.. Treatment OttC~Q8 fr8Qfment D,9C:~OC
~ MuOd'I GtOUl'owor81 MuOCV \
~ 0.... E a(roc:r,onl (,eet!
fr8Of"'*\t O,9C:~ ireaTmen! :',SCf"QlQe
MIIINAIM "
AUIIMAIM ..
TABLE 3
ASSEMBLED ALTERNATMS
-------
Alternative 2:
Alternative Water Supply
As an adjunct to Alternative 1 (No Action), new water supply wells
could be installed outside the bounds of the current or future aquifer
contaminant plume to replace the two existing city wells and provide
assurance of a water supply free of chromium contamination.
Groundwater would be pumped from the new wells to the existing water
storage and distribution system serving the airport area.
Chromium concentrations in water pumped from the city wells are
currently at background levels, within drinking water standards and do
not presently appear to be at risk from the United Chrome site.
However, an ongoing monitoring plan could be established which would
require regular sampling and analysis of city well water. Increased
levels would trigger use of an alternate water supply. Such a
contingency plan would function as a safeguard against potential
unknowns.
Alternative 3:
Soil Excavation
This alternative consists of excavating and removing highly
contaminated unsaturated soil from the site. The s011 would be
disposed of at the Arlington, Oregon, hazardous waste disposal facility
or an equivalent facility. The two areas of contaminated soil are
under the concrete floor of the building near the plating bath tanks
and the dry well disposal area outside the building. Total chromium
levels in these two source areas have been measured as high as 25,900
mg/kg and 162,580 mg/kg, respectively. A portion of the concrete floor
would have to be removed. Excavation would be down to the water table,
or a maximum of approximately 9 feet.
Alternative 4:
Unconfined Zone Groundwater Extraction
Alternative 4 consists of extraction of contaminated groundwater from
the unconfined zone, followed by treatment and off-site disposal.
The groundwater extraction system would consist of a grid of extraction
wells placed in the contaminated zone, down 15 to 20 feet to the
confining clay bed. Wells would be placed so that their influence
extended to include all contaminated areas including a portion of the
area under the United Chrome building. This alternative is expected to
entail long-term pumping from the upper unconfined zone because the
source areas (highly contaminated soil) will serve as continuing
-------
Alternative 5: Soil Flushing/Unconfined Zone Groundwater Extraction
This alternative consists of flushing contaminated soi1 in the two
source areas to remove soluble contaminantsp and extraction of
contaminated groundwater from the unconfined zone. These two remedial
activities complement each other to remove a11 sources of confined
aquifer contamination.
Soil flushing would consist of excavating to a depth of approximately 1
to 2 feet in each source area and continuously applying flush water to
the excavated areas. Recovered elutriate would be treated along with
the contaminated groundwater extracted from the rest of the unconfined
zone and disposed of off-site. This remedial action would require a
grid of recovery wells as described in Alternative 4.
Al ternati ve 6:
50i1 Excavation/Alternate Water Supply
This alternative consists of excavation and removal of highly
contaminated 50i1 (Alternative 3) combined with constructing new supply
wells to serve the airport area (Alternative 2). Removal of the
contaminant source areas by excavation will not assure protection of
the co~fined aquifer because of the threat from remaining contamination
in the unconfined groundwater zone. -This alternative assures that an .
uncontaminated water supply is available to the airport area should the
ongoing unconfined zone contamination result in the contamination of
the existing citY wells.
A1 ternative 7:
Confined Aquifer Extraction
This alternative consists of pumping the confined aquifer to extract
existing contamination and control migration within the aquifer. A
series of extraction wells would be placed into the confinea aquifer
contaminant plume for pumping. The extraction wells would be located
so their influence included all contaminated areas in the aquifer.
Extracted groundwater would be pumped to an onsite treatment system
followed by discbarge offsite. .
Pumping from the confined aquifer would be at significantly higher
rates than for pumping from the upper unconfined zone (Alternative 4)
because of higher aquifer permeabi1ities. With all contamination
remaining in place above the confined aquiferi the pumping system would
have to operate over a long period, perhaps up to 30 years, while the
upper contamination gradually disperses. .
Alternative 8:
Soil Excavation/Confined Aquifer Extraction
Alternative 8 consists of excavation and removal of highly contaminated'
soil (Alternative 3) combined with pumping of the confined aquifer
(Alternative 7) to prevent spread of contamination in the aquifer while
-------
5011 excavation, removal, and disposal would be the same as described
for Alternative 3. In addition, as described in Alternative 7, a
series of wells' would be installed into the confined aquifer
contaminant plume for pumping. The extraction wells would be located
so their influence included all contaminated areas in the aquifer.
Extracted water would be treated and disposed of off-site.
Alternative 9:
Supply
Alternative 9 consists of extracting contaminated groundwater from the
unconfined zone (Alternative 4) combined with constructing new supply
wells to serve the airport area (Alternative 2). Th.is alternative
woulG provide cleanup of the unconfined groundwater to eliminate
discharge of contaminants to nearby surface ditches and prevent leakage
of contaminants to the confined aquifer, and would also assure an
uncontaminated water supply for the airport area at all times.
Unconfined Zone Groundwater Extraction/Alternate Water
Alternative 10: Unconfined Zone Groundwater Extraction/Confined
Aquifer Extraction
Alternative 10'consists of extracting contaminated groundwater from the
unconfined zone (Alternative 4) combined with pumping of the confined
aquifer (Alternative 7). Extracting water from the unconfined zone
will eliminate discharge of contaminants to nearby surface ditches and
prevent leakage of contaminants to the confined aquifer. Extracting
water from the contaminant plume in the confined aquifer will reduce
and control migration within the aquifer. All extracted water would be
treated and disposed of off-site.
Zone Groundwater
This alternative is a combination of Alternatives 5 and 2. In addition
to cleaning up the contaminated soil source areas and the contaminated
unconfined zone groundwater, it also provides an uncontaminated water
supply to the airport area.
Alternative 12: Soil Flushin /Unconfined Zone Groundwater
xtractlon on lned AqUl er xtractlon
Alternative 12 is a combination of Alternatives 5 and 8. It provides
the most complete restoration of the site to pre-United Chrome
conditions. Soil flushing and groundwater extraction from the
unconfined zone and the confined aquifer are all remedial actions which
would remove contaminants from the site. All extracted water would be
-------
Section 300.68(f) of the National Con~ingency Plan (NCP) requires that,
to the extent possible, at least one remed1al alternative will be developed
for each of the following five categories:
1 .
Alternatives that treat or dispose of hazardous substances at an
off-site facility. Such a facility must be in compliance with all
applicable EPA standards.
Alternatives that attain applicable or relevant federal public
health or environmental standards, guidance, or advisories.
2.
3.
Alternatives that exceed applicable or- relevant federal public
health or environmental standards, guidance, or advisories.
Alternatives that prevent or minimize present or future migration
of hazardous substances and protect human health and the
environment, but do not attain the applicable or rel,vant federal
public health or environmental standards» guidance, or advisories.
4.
5.
No action.
Table 4 presents the alternatives in the Feasibility Study which
satisfy this requirement.
- -
The twelve alternatives were subjected to an initial screening to
eliminate the least suitable alternatives and narrow the list of potential
remedial actions for further detailed analysis. Three broad criteria were
used:
o
Technical feasibility. Technical feasibility includes: 1) a
general assessment of whether the technologies are feasible for
the site condition and are applicable to groundwater -
contamination, and 2) a general assessment of the alternative's
reliability in addressing the groundwater contamination.
o
.
Costs. Relative costs were developed for each alternative. The
cost estimates are conceptual (-50 to +100 percent) and reflect
relative rather than absolute costs because elements common among
alternatives performing the same remedial function may not be
included. These estimates are not intended to represent
construction costs.
-------
TABLE
REMEDIAL ACTION CATEGORIES POR ALTBRNATIVES
Jemedial Action Category
1.
Treat or di8po.. of hazardous
substances at aD off.ite facility.
2.
Attain applicable or relevant
federal public health or
environ88ntal standards.
J.
Exceed applicable or relevant
federal public health or
environmental standards.
4.
Prevent or minimize present or
future migration of hazardous
substances and protect human health
and the environment. but do not
attain the applicable or relevant
federal public health or
environmental standards.
5.
No action.
Alternative
Alternative J.
SoU excavation.
Alternative 6. Soil excavation/.
alternate water supply.
Alternative 8, Soil excavation/
confined aquif,r extractioD.
. Alternative 5, SoU .flushing/
unconfined zone groundwater
extraction.
Alternative II" SOil flushing/
unconfined zone groundwater
extraction/alternate water supply.
Alternative 12, Soil flushing/
unconfined zone groundwater
extraction/confined aquifer
extraction.
Alternative 2.
supply.
Alternative water
Alternative J,
SoU excavatioD.
Alternative I,
No action.
C08ID8nts
Contaainated soil sent to Arling-
ton or an equivalent facility.
Contaminated soil sent to Arling-
ton or an equivalent facility.
Contaminated soil sent to Arling-
ton or an equivalent facility.
Cleanup contaminated soil and
unconfined zone to protect
confined aquifer.
Cleanup contaminated soil and
unconfined zone to protect
confined aquifer. provide new
water supply.
Cleanup contaminated soil and
unconfined zone to protect
confined aquifer, pump aquifer
to protect city wells.
Does not prevent present or
future migration of contaminants.
Does not protect aquifer from
contamination.
Does not prevent present or future
migration of hazardous substances
or protect human health and the
-------
TABLE 5
INITIAL SCREENING SUMMARY
tedmical
!I1vUo=ent.al aDd
Publ1c Ifealth
Est.aat.ed
Cost.
($1
UtunaU".
10 No 1Ct1cm
o
..,.
o
.
o
~oo,ooo
600 ,000
20 Altamat1v. Vatu Supp17
30 5011 EIc:a.,aUoa
o
fI.. UnCODf1D84 %oDe Gz'ouDdVater
ExUKt!OD
5. 5011 nubiD9ItJac:=f1D8d
ZoD8 G&'uaadWater !xtncUOD
.
.
1,700,000
..
..
1 ,700 ,000
I. 5011 IKc:avauaa/A1tenat8
WatKSupp!7
'J. CoDf1Md Jqa1fU' ERncUCID
I.. Soil 1Iea.,.UoaICClDf1Ded
AquifU'. El&U8CUCID
.. tJDCODf1D8d ZoD8 GrauDdVatU'
!IcU8I:UaGIA1tenat. Water
SupplJ
10. tJDcaDf1De4 Zoae GrouDdntR
. !IcU8I:UaGICaDf1D8d Aqa.1fU'
EltzKt1aD .
o
.
800 ,000
.
.
1,000,000
1,500,000
o
.
.
.
1,300,000
..
.
1,700,000
u. sou nU8b1At/UDc:aDf1D8d
%ou GJ:ouDdW.t.r Ex~
uonlAlternat. WatU'
SUpplJ
12. SoU rluaJUnt/UDCODf1D8d
10M GrauDcSvatU' ExtnCt10Dl
CoDf1Ded AqW.fU' ElttneUCID
..
..
1,900,000
..
..
1,700,000
- Extz881J net.UV8 eU8CU.
. NeqaUV8 eUec:t.8, but not 9AAt 8ftou;b t.o be sol. jwaUf1caUon for e1JJ11naUnq aD
alt..rD&UV8.
o No c:h1D98 fra u!aunt coccUUou, or 'Ie" 11t.t.l. pos1Uve or n8qaUve effects.
. A pos1t1ve or 8Od8rat81y pos1t1ve benefit..
-------
Alternatives 6, 9, and 11 were eliminated because they consist of
remedial cleanup measures designed to protect the confined aquifer, in
addition to providing a new alternative water supply which negates the
necessity for aquifer protection. Alternative 7 was dropped from further
consideration because it has no provision to prevent additional contaminants
from entering the confined aquifer. It is a passive response targeted to
allowing contamination to occur and then removing it. It is likely that
extraction (and subsequent treatment and disposal) under this alternative
could be required for 30 or more years. Alternative 8 was also eliminated
because it has no provision for immediate reduction or prevention of
contaminant migration to the confined aquifer. It is likely that operation
of this alternative would also be required for a relatively long period of
time as contaminated water in the unconfined zone continued to migrate to
the confined. aquifer.
A more detailed analysis was then conducted of the seven remaining
alternatives. This analysis consisted of a technical evaluation which
assessed the performance, reliabilitY, implementability, and safety of each
alternative. Public health and environmental considerations, institutional
considerations, and cost estimates for each alternative were also
evaluated. Table 6 summarizes the results of this detailed analysis.
Alternative 1, No Action, was eliminated because it would allow the
conti nue'd mi grati on of chromi um contal!li nati on in both the' groundwater and
surface drainage system. The contaminant plume would continue to spread and
could eventually affect the drinking water supply wells at the airport
complex. Even if the contaminant plume did not reach the existing
production wells at concentrations high enough to endanger public health, it
would continue to render an increasingly larger portion of the aquifer
around the UCP site unusable. This could potentially lead to future
restrictions on the usage of the site, as well as restriction on future well
locations and groundwater usage. .
Alternative 2, Alternative Water Supply, was eliminated because while
it would provide immediate assurance of no contamination from the UCP site
entering the airport complex water supply, it would do nothing to mitigate
the existing contamination around the site. The potential for continued
migration of contamination in the shallow zone, both laterally and into the
deeper production aquifer would remain as would the potential for future
land use and groundwater restriction under the No Action alternative.
Alternative 3, Soil Excavation, was eliminated for several reasons.
Because of the extensive area contamination, excavation would be limited to
the most highly contaminated soils near the dry well and the plating tanks.
Contaminated soils outside the areas being excavated would continue leaching
and remain as ongoing sources of groundwater contamination. Also, the 1984
Hazardous and Solid Waste Amendments to RCRA state in Section l002(b)(7)
that ureliance on land disposal should be minimized or eliminated, and land
disposal, particularly landfill and surface impoundment, should be the least
-------
T ABL E 6
SUMMARY OF PETAlLED EVALUATIONS
AUemaU"e
I 1 1 . 5 10 11
TecbDOl~le. Included
Alternate Water Suppl, NA f NA NA ItA HA IIA
SoU ExcavaUoa ItA NA P ItA ItA NA ItA
SoU FluablnCJ ItA NA HA. ItA P ItA P
Unconfined lone Groundvater HA ItA ItA P P P P
ExtracUon
Confined AquUer ExtracUoa ItA HA 'HA NA NA P P
Extracted Water Treataent NA NA ItA P P P P
Pedonaaoce (Effecu"eness)
Ellalnat.. Potenllal Exposure to N H P III P III P
Coot_lnated 8011
Assures Safe Local Watelr SuppA, iii Jj) M , K» lP P
IteaOvell Coat_inaUoa rr08l 911 III RiI , K» IF' IP
UnconUD8d 10-
ReaD".. Cont881natlooFr08l II! IMI 81 II All P IP
Confined aquifer
...
Extracted Water AdeqUate., au IliA RIA IP IP P P
Tre.t.d for OAscb8rge
lIeHabUltl
Hev Suppl, Wells HA P RiA Ni Hi IlIA Hi.
ExcavaUon HA NA P NA NA NA HA
Extraction Well. NA ItA HA P P P P
SoU Flusblng NA NA HA NA 0 ItA 0
-------
TABLE 6
(continued)
AUenaUve
1 1 :I . 5 10 U
18ple.entabilitl r '
E4slly Installed "Itb NA P P P P P .
Conventional Equlpaeot
Total Tiae to 18ple88Dt NA P P .. .. .. ..
Safety IDurlng lapleaentaUon)
Requires Worker/Operator NA p N .. N N N'
Protection
Public Health and EnviroR88ntal
Consider at lOPS
Potent I. I Huaan Exposure During NA p .. .. .. .. ..
lap le.entat ion
Assures Safe Water Supply NA P N P P P P
Provides Soae Degree of Site N N P P P P P
I<~storation
Institutional Considerations
Complies with ~RA NA NA P P P P P
C08II11es with CWA NA NA NA P P II P
COlDVl ies with ()IpS N N .N P P P P
Cost
Cd~Hdi cost 1$ In thousalldsl 0 111 599 919 1,06) 1,.51 1,580
Present Worth ($ in thousandsl 0 111 599 1,1U 1,699 1,1H 2,510
Nl1I' E: NA ; Not Applicable
.. - Positive Aspect
N ; Ne9atlve Aspect
0 ; N~utral (nelUler positive nor ne9atlvel aspect
CWA ; Clean Water Act
GWp,a = Groundwater Prot~ctlon Strate9Y
-------
Alternative 4, Unconfined Zone Groundwater Extraction, was eliminated
because while it would reduce contamination 1n the shallow groundwater, it
would not provide for any cleanup of the contaminated soils in the source
areas nor the contaminated groundwater in the lower production aquifer.
Also, this alternative would allow the continued migration of the
contaminated groundwater in the lower zone. While this might not
immediately impact the existing airport production wells, it would render an
increasingly larger portion of the production aquifer around the UCP site
unusable. Again, this could lead to future land use and groundwater
restrictions. .
Alternative 5, Soil Flushing and Unconfined Zone Groundwater
Extractionv was eliminated for the same reasons as Alternative 4. While
this alternative did address the reduction of contamination in the
unsaturated soil above the shallow groundwater, it did not include any
treatment of the contaminated groundwater in the deeper production aquifer
beneath the site. The Feasibility Study concluded that the combined efforts
of Alternative 5 would reduce the migration of chromiu~ into the lower
production aquifer to a level that would ensure that the Primary Drinking
Water Standard of 0.05 mg/l could be maintained at the nearest production
well some 3000 feet away. The study predicted, however, that the natural
attenuation of the existing contamination. in the lower aquifer might still
result.in chromium levels above the drinking water standard nearly "1500 fee.t
from the.site. Thus, all of the groundwater within that area might
ultimately be rendered unusable. After considerable evaluation of this
alternative, EPA and ODEQ determined that allowing the continued degradation
of this production aquifer would be unacceptable.
Alternative 10, Unconfined Zone and Confined Aquifer Groundwater
Extraction, is similar to Alternative 4 with the addition of a second deep
. well system to extract the contaminated groundwater from the production
aquifer. While this alternative does address the cleanup of the lower zone,
it does not include any treatment or removal of the contaminated soil in the
unsaturated zone above. the shall ow groundwater tabl e. As in Al ternative 4,
this contaminated soil would remain as a potential source of future
groundwater contamination. For this reason Alternative 10 was eliminated.
Table 7 presents a summary of the cost estimates for the alternatives
examined .1n the detailed analysis. .
COMMUNITY RELATIONS
There was a public comment period on the Remedial Investigation and
Feasibility Study reports from August 19 through September 9, 1985. Copies
of the reports were available for review at the Benton County Health
Department and at the Corvallis Library. A public meeting was held on
-------
TABLE 7
COST ESTIMATE SUMMARY FOR REMEDIAL ACTION ALTERNATIVES
Estimated Costs (1985)
Annual Present
Alternative Capital O&M Worth
2--Alt.ernat.ive Wat.er
Supply $ 172,000 none $ 172,000
3--Soil Excavation" 599,000 none 599,000
4--Unconfined Zone
Groundwat.er
Ex'tracti.on 929,000 $168,000 a
1,745,000
5~-Soil rlushinql
Unconfihed Zone
Groundwat.er b
Extract.ion 1,063,000 168,000 1,699,000
10--Unconfined Zone and
Confined Aquifer
Groundwat.er a
Ext.raction 1,452,000 261,000 2,724,000
. 12--50i1 .Flushinql
Unconfined Zone. and
Confined Aquifer
Groundwat.er b
Extraction 1,580,000 261,000 2,570,000
a, years1 10 percent interest..
-------
meeting and 'public comment period were sent out to 44 nearby residents,
b~51nesses. elected officials, city and county agencies and local news
medii. Eighteen people attended the public meeting. Comments were received
from the Sierra Club, the League of Women Voters of Corvallis, the city of
Corvallis, and ODEQ. A more detailed discussion of the comments and agency
responses is included in the attached Responsiveness Summary.
CONSISTENCY WITH OTHER ENVIRONMENTAL LAWS
All facets of the proposed Remedial Alternative will be consistent with
the technical requirements of other environmental laws. The off-site
transportation and disposal of the excavated soil will be in accordance with
applicable RCRA regulations, including manifesting of wastes and shipment to
a' RCRA-perm1tted land disposal facility. All off-site disposal shall be in
compliance with the policies stated in the Procedure for Planning and
Implementing Off-Site Response Actions as published in the Federal Register,
Volume 50, Number 214, November 5, 1985.
An NPDES permit will be obtained for the treated effluent discharge to
Muddy Creek. This discharge will be monitored to ensure that the Willamette
River basin standard for chromium of 0.02 mg/l is maintained throughout the
year.
RECOMMENDED ALTERNATIVE
The recommended alternative is number 12 which would 'consist of
unconfined zone and confined aquifer groundwater extraction, treatment, and
surface discharge. This alternative would also include the limited
excavation of contaminated 5011 from the dry well and plating tank areas for
the purpose of constructing two percolation basins. As a part of this
excavation, the plating tanks and -any residual sludge contained in them~
would be removed and either recycled or disposed of at a RCRA-permitted land
disposal facility. These basins would be used to flush the contaminated
soil in the unsaturated zone above the shallow groundwater table. In
addition, the open drainage ditch within the contaminated area would be
culverted to protect the local surface drainage ditch system from
contamination.
The objective of this alternative is to remove contamination in the
confined aquifer and control the migration of further contamination from the
upper unconfined zone. Until the upper zone is cleaned up, it will continue
to seep contamination through the confining clay bed into the underlying
aquifer.
The cleanup criteria for the confined aquifer is 0.05 mg/l chromium,
the drinking water standard, because this aquifer is considered a drinking
water source and ,;n direct hydraulic connection to the local drinking water
-------
.
The cleanup criteria for the unconfined zone is 10 rng/1 chromium. This
concentration represents the minimum cleanup required to protect the local
drinking water supply. The drinking water standard of 0.05 mg/1 chromium
was not used because the unconfined zone is not used as a drinking water
source anywhere in the area. and because the present level of contamination
would likely make it technologically or economically infeasible to achieve
this standard.
The contaminated groundwater will be extracted from the two zones by a
system of approximately .fifteen shallow wells and five deep wells as shown
in Figures 5 and 6.
The groundwater extracted from both zones will be treated to reduce the
chromium concentration to an acceptable level for surface water discharge.
The proposed treatment process is shown schematically in Figure 7. It could
be constructed using vendor-supplied. skid-mounted package units so that
with a minor amount of engineering. interconnecting piping and wiring. the
total system could readily be operable. .
The extracted groundwater would be pumped to an influent holding tank
and then transferred to a chemical reduction tank where the hexavalent
chromium.would be reduced to the trivalent state. The groundwater
containing reduced trivalent chromium woul.d then flow to a pH adjustment.
tank to elevate the pH to, betWeen 9 and 10. At .this pH. metals present in
the groundwater will precipitate. out as hydroxides. The groundwater would
then flow to a flocculation tank where a polymer solution would be added to
enhance settling of the precipitate. From the flocculation tank the water
woul d flow to a c 1 ar; fi er for settli ng. A treated effl uent concentraton of
0.3 to 0.4 mg/l chromium is expected.
The settled sludge would be periodically drawn from the bottom of the
clarifier. At the present time. it is assumed that this sludge will be a
hazardous waste and must be disposed of at a RCRA-permitted facility.
The treated effluent would. be pumped through a buried pipeline to Muddy
Creek for discharge as shown in Figure 8. The creek provides a minimum of a
10 to 1 dilution of the 50.000 gallon per day effluent flow based on
available minimum su~r flow data. If. for any reason. the treated
groundwater should not meet the desired water quality. transportation by
truck and disposal at the Corvallis wastewater treatment plant could be used
as a temporary alternative.
The estimated total capital cost of this alternative is $1.580,000 and
the total annual operating cost is $261.000. A more detailed summary of the
estimated costs is presented i1\ Table 8. .
The UCP Feasibility Study was structured to meet the requirements of
the revisions to the NCP (Federal Register. Volume 47. Number 137, July 16.
1982). and a1 so EPA IS IIGui dance on Feasi bi 11 ty Studies Under CERCLA"
(EPA/540/G-85/003 June 1985). Alternatives were developed to address the
-------
//'
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total cn.cmtum (mg/I)
..---
,
- -'
,
01 ~r:r"
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I .
~~---------------~
AGUIIS
ALTERNATM .
UNCONANED ZONE E)(1IACt10N WILL
PROPOSED LAYOU1'
UNITS) CHAOME FS
.~ ---
- .... -- ..
Pa"emerH
851-
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. :'.;
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e
P,op ~ lid ....aow extr8CtIon .....
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'::..:::-
-------
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I '
1 e"tent of p'awed field
- Fence
~
- -. Pavem.nt/Pl1rtfiftQ
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pl.oweo
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FIGURE 6
ALTElNAT1VE 10
CONFINED AQUI" EXIIAC110N WB.L
PIOPOSID LAYOUt
-------
...
~*= CQ."....n' "*-<....
==._..,...u..~.;:
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.......
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~~MENI iYSilE1M!
-------
lIu -
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--. j
o
u
.000
2000
..
'I
t" = 2000'
f. IGURE 8
PROPOSED DISCHARGE IOUIE
10 MUDDY CREEK
lNlED CHROME fS
-------
TABLE 8
COST SUMMARY
ALTERNATIVE 12: SOIL FLUSHING/UNCONFINED ZONE
AND CONFINED AQUIFER GROUNDWATER EXTRACTION
Capital Cost Items
General
Mobilization, Bondinq, Insurance
Health and Safety proqram
Equipment Decontamination
Equipment Demob.ilization
Unconfined Zone Groundwater Extraction
Confined Aquifer Groundwater Extraction
Onsit. Wastewater Treatment
Effluent Disposal
Demolition
Soil Excavation/Disposal
Soil "rlushinq
surfaee Drainaqe
construction Subtotal
Bid c.ontinqencies (15')
Scop@ Continqencies (15')
Construction Total
Permittinq and Leqa1 (3')
services Durinq Construction (10')
Total Implementation Cost'
Enqineerinq Desiqn (10')
TOTAL CAPITAL COST
Annual O~eratinq Cost Items
Administration
operations
Maintenance
Disposal
Sample Analysis
O&M SUbtotal
Continqencies (20')
TOTAL ANNUAL OPERATING COST
PRESENT WORTH (5 yearS7 10' interest)
. TOTAL PROJECT COST
Estimated
Cost
~
$
51,000
46,000
24,000
682,000
137,000
32,000
48,000
3,000
~
1,OJJ,000
155,000
~
1,J4J,OUU
.31,000
103,000
~
103,000
$1,580,000
Estimated
Annual
Cost
S 42,000
96,000
36,000
20,000
24,000
218,000
43,000
$ 261,000
$ 991,000
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.
At thlt time, the applicable standard used in these alternatives was
the Safe Drinking Water Act Maximum Contaminant Level for chromium (0.05
mg/l). This standard was to be applied at the nearest existing receptor
point, the city of Corvallis drinking water wells approximately 3000 feet to
the northeast. With this objective, Alternative 5 was the preliminary
choice for the cost-effective alternative at the time of the public meeting.
However, the ODEQ conrnented on the Feasi bi H ty Study stati ng that the
Oregon Groundwater Quality Protection Policy could not allow the loss of
beneficial use of the production aquifer that would occur with Alternative
5. While Alternative 5 would ensure meeting the drinking water standard for
chromium at the city wells, it would allow the contamination in the aquifer
near the site to attenuate naturally over time. This would ultimately
result in long-term degradation of the aquifer as far as 1500 feet
downgradient of the site, with chromium concentrations exceeding the
drinking water standard. ODEQ stated further that the gOll should be to
meet the drinking water standard at the plant site boundary.
.
Upon review of these comments, and those of the city of Corvallis and
several citizens' organizations, EPA agrees that the drinking water standard
should be met at the plant site boundary. This position is consis~ent with
the groundwater 'protection provisions of RCRA (40 CFR 264 Subpart F); in
particular, Section 264.92-that the chromium standard of 0~05 mg/l should
not b~ exceeded in the uppermost-aquifer underlying the site beyond the.
"point of compHance". Section 264.95 defines this point of compliance as a
vertical surface located at the hydraulically downgradient limit of the site
that extends down into the uppermost aquifer underlying the site. Further,
Section 264.l00(b) states that a corrective action program must be
implemented to prevent hazardous elements (in this case, chromium) from
exceeding their respective concentration limits at the compliance point by
removing them or treating them in place.
This position is also consistent with EPA's Ground Water Protection
Strategy goal of maintaining the highest beneficial use of Class II
aquifers. Finally, we believe this decision is closer to our understanding
of what congress' intent is for the pending reauthorization of the
Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA or SUperfund l.
Given these objectives, EPA has determined that Alternative 12 is the
only alternative which will attain the applicable standard at the plant site
boundary. No other alternative would sufficiently address both the public
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OPERATION AND MAINTENANCE (OIM)
. The proposed treatment system was described in the preceding section.
It relies primarily on chemical reduction and precipitation technology that
is widely used for the treatment of hexavalent chromium wastewaters in the
metal plating industry. The performance history is good. Although the
proposed process has continuous operation. it includes holding tanks for
production for two full days. This allows daily testing of process water to
help insure maximum reliability.
The operation and maintenance activities for the 'groundwater extraction
system and, the on-site groundwater treatment system would include:
.
process operation,
chemical feed management
.
o
routine maintenance of pumps and other mechanical equipment such
as the filter press and chemical mixer motors
sampling and analysis of ex~racted groundwater and treated effluent
.
sludge management - handling and final disposal
The estimated annual operating costs are set forth in Table 8. The
time required to achieve cleanup is estimated at five years with a possible
range of three to eight years.
.
The Emergency Board of the Oregon Legislature has approved $1 il16.000
which represents the state's cost share of the total remedial investigation.
feasibility study. design. construction. and first year operation and
maintenance costs for this site. .EPA funding of future activities at UCP is
pending the reauthorization of Superfund. Under the present lawi the
federal share of the costs would be fifty percent (5~). EPA funding for
operation and maintenance costs is anticipated to cover the first year after
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.
SCHEDULE
c
The key milestones and dates for project implementation are as follows:
. Approve Remedial Action (sign ROD) September 1986
. Superfund State Contract September 1986
. Initiate Work Assignment for Design October 1986
. Complete Desi gn . March 1987
. Superfund State Contract for Construction April 1987
. Start Construction May 1 987
. Complete Construction September 1987
At this time, EPA anticipates funding the design portion of this
project through an advance match using state funds. However, the initiation
of construction activities will depend on the reauthorization of Superfund
and federal funds being available to complete the project. .
FUTURE ACTIONS
No additional remedial activities are planned at this time. After
completion of construction the only activity will be the operation and
maintenance of the groundwater extraction and treatment systems, and
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UNITED CHROME PRODUCTS, INC.
CORVALLIS, OREGON
RESPONSIVENESS SUMMARY
~
OVERVIEW
At the public meeting held on August 21,1985, the Environmental
Protection Agency (EPA) presented Alternative 5 from the Feasibility Study
as the preferred remedial alternative. This alternative would have
addressed the original primary objective of protecting the existing drinking
water wells at the airport complex. There was very little comment from the
general public on this proposal. However, after review and discussion of
the alternatives, the Oregon Department of Environmental Quality (ODEQ»
recommended more extensive remedial measures than those provided for in the
original proposalo In response, EPA agreed to change to Alternative 12 in
the Feasibility Study.
This alternative specified in the Record of Decision (ROD) involves the
installation of wells to extract the contaminated groundwater from both the
shallow saturated zone and the lower confined aquifer. This groundwater
would be treated on site to remove chromium contamination and then
discharged to nearby Muddy Creek.
The final alternative more closely addresses the objectives of the
state.s Groundwater Quality Protection Policy as well as the groundwater
protection provisions of Resource Conservation and Recovery Act (RCRA).
BACKGROUND ON COMMUNITY INVOLVEMENT
There has been little community interest in the Remedial Investigation
ana Feasiblity Study to date. EPA.s community relations effort began in
November 1984 when the first fact sheet was released on the upcoming.
investigation. There were no significant comments or questions from the
public on this fact sheet or the subsequent field work at the site.
Eighteen people attended the public meeting on August 21,1985. Twelve
of these people were from government agencies, consulting firms, and the
media. There were three representatives from two citizens. groups. The
remaining three people were from the general public.
The general response from ODEQ, the city of Corvallis, and the Sierra
Club was for a more thorough cleanup than that originally favored by EPA.
After evaluating all of the comments, and after extensive discussion with
ODEQ, EPA revised its position to recommend Alternative 12 from the
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2
SUMMARY OF PUBLIC COMMENTS AND AGENCY RESPONSES
. The initial comment period was held from August 19 through
September 9, 1985, to receive comments from the public on the draft
Feasibility Study. The only comments received during this period were from
the Sierra Club and the League of Women Voters. The city of Corvallis
requested a short extention of the comment period so that the City Council
could review the alternatives. The city provided comments to EPA on
October 23, 1985. The ODEQ requested an indefinite extention of the comment
period to conduct an extensive examination of the alternatives and their
relationship to the state environmental statutes and policies. EPA received
the initial ODEQ comments on December 23, 1985. Numerous discussions and
meetings between EPA and ODEQ were conducted over the next several months
culminating in ODEQ providing to EPA a preliminary recommendation of
Alternative 12 on May 19, 1986.
11
c
The comments received on the draft Feasibility Study alternatives and
the EPA responses are summarized below:
1.
The League of Women Voters of Corvallis wrote asking that the
public comment period be extended thirty days. In response to
this request and those of the state and the city of Corvallis, EPA
extended the comment period indefinitely. This indefinite
extension was possible because of the project slowdown caused by
the delay of the reauthorization of Superfund. An article in the
September 5, 1985, edition of the Corvallis Gazette-Times noted
this extension. .
2.
The Marys Peak Group of the Sierra Club wrote supporting a
combination of Alternatives 3 and 5. While EPA ultimately
supported a more extensive cleanup than originally proposed, it
did not include the additional excavation in Alternative 3. This
is primarily because of congress' intent in the Hazardous and
Solid Waste Amendments of 1984 to make land disposal the
least-favored remedial alternative.
3.
The city of Corvallis had four major concerns with the proposed
cleanup alternative:
(1) assurance of a safe drinking water supply for the airport
facn i ti es;
(2) the environmental impact of the discharge of process water to
Muddy Creek;
(3) the disposition of the United Chrome Products building during
and after the cleanup process; and
(4) clarification of the cleanup goal and how the most
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3
EPA be11eves that the implementation of Alternative 12 will adequately
address the concern of contamination in the production aquifer. The
extraction of contaminated groundwater from this aquifer near the site
should prevent any further migration toward the current city production
wells some 3000 feet away. Several monitoring wells are in place between
the site and the city wells which would detect any contamination migration
long before it would affect the city wells.
The discharge of process water to Muddy Creek will be closely evaluated
during the design of the remedial alternative. Extensive monitoring will be
conducted to ensure that National Pollution Discharge Elimination System
discharge permit standards will be met at all times. The design of the
treatment system calls for a holding tank sized for two days. production.
This holding time will allow for proper process monitoring of the final
effluent prior to discharge, thus providing a safeguard against treatment
process equipment failure.
,.,
~
The final disposition of the United Chrome Products building i5
undecided at this time. The city has indicated in their comments to EPA
that they have no strong desire to save the bun ding, and would favor its
destruction-if such action would shorten the cleanup process. During the
Remedial Design EPA will direct- its consultant to examine the relative costs
of cleaning the contaminated portion of the building versus demolishing the
building completely. Once these costs are available, a final decision on
the building will be made. after consultation with the city ana ODEQ.
The original cleanup objective was to protect the existing city
drinking water wells at the airport complex. Given the input from ODEQ,
this objective has now been expanded to include protection of as much of the
production aquifer near the site as possible. The goal is to achieve the
drinking water standard for chromium of 0.05 milligrams per liter at the
downgradient property boundary. EPA and ODEQ now believe Alternative 12 is
the only alternative examined which can meet this new objective.
ODEQ's initial comments to EPA in December 1985 were primarily
requesting clarification of specific elements of the draft Feasibility Study
report. They also requested a more detailed explanation of the procedures
in the National Contingency Plan for conducting a Remedial Investigation ana
Feasibility Study, and for selecting a remedial alternative. Over the next
five months. EPA and ODEQ continued discussions on a variety of technical
and policy issues regarding this project.
The applicability of Oregon's Groundwater Quality Protection Policy
emerged as one of the most important concerns for ODEQ. They finally
determined that the state goal would be to attain the drinking water
standard for chromium in the confined aquifer at the site boundary. EPA
responded by agreeing to revise the original scope of the project to include
. this objective. It was this change that ultimately led to the selection of
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~ -.
1
i
4
REMAINING CONCERNS
. EPA is not aware of any remaining citizen concerns at this time. A
fact sheet will be sent out, after the Record of Decision is signed,
describing the upcoming design and remedial action activities. Additional
community relations activities will be conducted as interest 1n the project
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