United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R07-89/024
September 1989
Superfund
Record of Decision
Chemplex, IA
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50272.101
REPORT DOCUMENTATION 11. REPORT NO.
PAGE EPA/ROD/R07-89/024
I ~
3. Reclpienra Acce..ion No.
4. l1Ue and Subtitle
SUPERFUND RECORD OF DECISION
Chemplex, IA
First Remedial Action
7. Author(a)
5. Report Date
09/27/89
6.
8. Perfonning Organization Repl. No.
II. Perfonnlng Orgalnlzatlon ...... and Add-
10. Project/TaaklWork Unit No.
11. Contract(C) or Grant(G) No.
.-
(C)
(G)
.
1 ~ Sponaorlng Organization Name and Addre..
U.S. Environmental Protection
401 M Street; S.W.
Washington, D.C. 20460
13. Type 01 Report'" Period Covered
Agency
800/000
14.
15. Supptementary No.a
16. Abetract (Umlt: 200 warda)
The Chemplex site is in Clinton County within 5 miles of Clinton, Iowa, and includes a
landfill, a waste water treatment plant, and an adjacent facility which manufacturers
high and low density polyethylene. Several residences with private wells are located
around the site and a tributary to Rock Creek lies to the west and southwest of the site.
Rock Creek eventually discharges to the Mississippi River just above the Upper
~ississippi River Wildlife Refuge. The direction of ground water flow beneath the site
~ppears to be toward the southwest, although a mounding effect is causing ground water to
flow radially from the center of the landfill. From 1968 to 1978 the landfill area was
used for disposal of various plant wastes including black oily sludge, scrap
polyethylene, construction debris, and carbonate sludge. The debutanized aromatic
concentrate (DAC) area, which consists of a pit and DAC product storage and loading
areas, was contaminated by DAC spillage. In 1987, waste was reportedly removed from the
pit and disposed of in a RCRA permitted landfill. Wastes and spills have contaminated
the soil and ground water underneath the landfill and DAC areas. This first operable
unit will address the plumes of ground water contamination. A subsequent operable unit
remedy for this site will address the cleanup of soil and other ground water remediation
that may be required. The primary contaminants of concern affecting the ground water are
VOCs including benzene, toluene, xylenes, TCE, and PCE; and other organics including
carcinogenic and noncarcinoqenic PARs. (See Attached Sheet)
17. Docurnant Analyala L Deacriptora
Record of Decision -Chemplex, IA
First Remedial Action
Contaminated Media: gw
Key Contaminants: VOCs (benzene, toluene, xylenes, TCE, PCE), other organics (PAHs)
b. Identiller8l0pen-Endad Tenna
c. COSA 11 Reid/Group
18. Availability Statement
1 II. SecurIty CIa.. (Thia Report)
None
20. Security Cia.. (Thla Page)
Nnno
21. No. of Pages
65
22. Price
(See ANSI Z311.18)
See IIIII/ructJolIII on ReIlet86
2(4-77)
(Formerty NTI5-35)
Department 01 Commerce
-------
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(4-77)
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EPA/ROD/R07-89/024
Chemplex, IA
First Remedial Action
16.
Abstract
(continued)
The selected remedial action for this first operable unit includes pumping and
pretreatment of ground water followed by treatment of pretreated ground water at the
existing onsite biological activated sludge wastewater treatment plant with discharge to
the Mississippi River via Rock Creek; and implementation of ground water use
restrictions. The estimated pre~ent worth cost for this remedial action is $2,622,000,
which includes an annual O&M cost of $219,600 for 30 years.
.
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CHEMPLEX SITE
RECORD OF DECISION
THE LANDFILL AND DAC AREAS
GROUND WATER OPERABLE UNIT
September 1989
-------
CHEMPLEX SITE
RECORD OF DECISION
THE LANDFILL AND DAC AREAS
GROUND WATER OPERABLE UNIT
September 1989
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DECLARATION }o'OR THE RECORD OF DECISION
SITE NAME AND LOCATION
Chemplex Site
Clinton, Iowa
STATEMENT OF BASIS AND PURPOSE.
This decision document presents the selected operable unit
remedial action for the Chemplex site, in Clinton, Iowa, which
was chosen in accordance with the requirements of the
Comprehensive Environmental Response, Compensation, and Liability
Act of 1980 (CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA) and, to the extent
. practicable, the National Oil and Hazardous Substances Pollution
Contingency Plan (NCP). This decision document explains the
factual and legal basis for selecting the remedy for this site.
The Iowa Department of Natural Resources concurs with the
selected remedy. The information supporting this remedial action
decision is contained in the administrative record for this site.
ASSESSMENT OF THE SITE
Releases of volatile organic compounds and polynuclear
aromatic hydrocarbons have occurred in the soil and ground water
at this site.
DESCRIPTION OF THE SELECTED REMEDY
This operable unit is the first of at least two operable
units for the site. This ground water operable unit remedy will
initiate control over the plumes of ground water contamination in
the landfill and Debutanized Aromatic Concentrate (DAC) areas. A
subsequent operable unit remedy for this site will address
cleanup of the soils in these two areas and other ground water
remediation that may be required. Additional Remedial
Investigation/Feasibility Studies (RI/FSs) may be conducted in
the future on other areas of the Chemplex site.
The major components of the selected remedy include the
following:
- Institutional controls to restrict use of ground water.
:
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3
- Extraction of ground water by placement of extraction
wells in the plumes of the two areas.
- Pretreatment of the extracted groupd water.
- Treatment of the extracted ground water at the existing
onsite waste~ater treatment plant.
- Discharge of the treated ground water to the Mississippi
River via a federally permitted discharge (NPDES permit).
DEC~RATION OF STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that
are legally applicable or relevant and appropriate to the
remedial action, and is cost-effective. This remedy utilizes
permanent solutions and alternative treatment (or resource
recovery) technologies to the maximum extent practicable, and it
satisfies the statutory preference for remedies that employ
treatment technologies that reduce toxicity, mobility, or volume
as their principal element.
Because this remedy will result in hazardous substances
remaining on site above health-based levels, a review will be
conducted within five years after commencement of remedial action
to ensure that the remedy continues to provide adequate
protection of human health and the environment.
/}/p/z" I ~~
fSlgnatur~
EPA Regional Administrator
'1"' "2- 7 -fr? .
Date
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4
1.0
INTRODUCTION
1.1
SITE DESCRIPTION
The Chemplex site (also known as Quantum Chemical
Corporation, herein Quantum) is located within 5 miles of
Clinton, Iowa in Clinton County~
The site includes a landfill
and the adjacent facility, which manufactures high and low
density polyethylene (herein the Quantum facility).
The Quantum
facility has been in operation since approximately 1967.
As
. shown on Figure 1-1, the landfill and debutanized aromatic
concentrate (DAC) area within the Quantum facility are the focus
of this Record of Decision.
From 1968 to 1978, the landfill area was used for disposal
of various plant wastes generated at the Quantum facility plant
including black oily sludge, scrap polyethylene, construction
debris, and carbonate sludge.
The principal contaminants of
concern in the landfill include benzene, toluene, ethylbenzene,
and xylenes (BTEX), polynuclear aromatic hydrocarbons (PAHs) , and
the chlorinated hydrocarbons; trichloroethylene (TCE) ,
tetrachloroethylene (PCE), and 1,2-dichloroethylene.
The plant
wastes have contaminated the soil and ground water underneath the
landfill.
The DAC area consists of the "previous basin" and DAC
product storage and loading areas.
The previous basin, a pit,
was used as a temporary storage area during reconstruction of the
polishing basin (the last unit of the current onsite wastewater
-------
Figure 1-1
. t 5 Area
DCSlqna e
-------
,1-, '" j II
;. ,I", " t, ,'.
5
. treatment plant) from 1977 through 1987. .According to the
potentially responsible parties (PRPs) for~his site, in 1987 the
waste was removed fro~ the previous basin and disposed of in a
RCRA permitted landfill.
The principal contaminants of concern
in the DAC area are BTEX and PAH compounds.
Although extensive
sampling to detect the chlorinated hydrocarbons was not conducted
in either the landfill or DAC
areas, EPA believes that these
compounds are more prevalent in the landfill area than the DAC
area.
This is because chlorinated hydrocarbons may have been
disposed in the landfill and the DAC product does not contain the
chlorinated hydrocarbons.
However, chlorinated hydrocarbons were
detected in the DAC area.
Contaminated media in the DAC area
include the soils and upper and lower ground water aquifers.
The lead agency for this site is EPA.
The support agency is
the Iowa Department of Natural Resources (IDNR).
1.2
ENFORCEMENT HISTORY
On September 18, 1987, EPA entered into an Administrative
Order on Consent, EPA Docket No. 87-F-0012, (herein Consent
Order) with the potentially responsible parties (PRPs), USI, now
Quantum Chemical Company (herein Quantum), ACC Chemical Company
(herein ACC) and Getty Chemical Company (herein Getty), to
investigate the landfill and DAC areas.
The Consent Order was
issued pursuant to Section 106(a) of the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980
-------
6
(CERCLA), 42 U.S.C. S9606(a) and Section 3013 of the Resource
Conservation and Recovery Act., as amended-(RCRA), 42 U.S.C.
S 6934.
In March 1988, the PRPs contacted the Agency and
requested a modification of the Consent Order and an extension of
time to complete the requirements of the Consent Order.
On
August 16, 1988, the Consent Order was amended and Getty and ACC
were required to submit the final remedial investigation/
feasibility study (RI/FS) reports for the DAC and landfill areas
no later than December 1988.
EPA received the draft RI/FS report
in December 1988.
EPA reviewed the draft report and sent
numerous comments and recommended revisions in April and May
1989.
The EPA found that the RI/FS report did not fully
characterize the nature and extent of contamination in the DAC
and landfill areas, nor did the feasibility study consider all of
the viable remedial alternatives for the treatment of ground
water from these areas.
In June of 1989, the PRPs submitted the
final RI/FS report.
Because information gaps remained in the
final report, EPA contracted with Jacobs Engineering to prepare a
Focused Feasibility study Report.
The Focused Feasibility study
Report, the RI/FS submitted by ACC and Getty, and EPA's comments
and recommended revisions thereto, all form a basis for this
Record of Decision.
The Quantum facility, including the DAC area, but excluding
the landfill area, is regulated by RCRA.
The landfill was closed
in 1978 prior to the effective date of the RCRA regulations
-------
7
governing the operation of such facilities.
At t!.at time, ACC
and Getty operated the landfill and it was-part of the
polyethylene manufacturing facility, which was known as the
Chemplex Company.
In 1984, whe~ Quantum began operating the
facility, the landfill was subdivided from the facili~y.
The
city of Clinton, Iowa owns the real property where the Quantum
facility is located as well as the landfill.
The City leases the
facility to Quantum and the landfill to Getty and ACC.
The Quantum facility currently operates as an interim status
RCRA facility with authority for the storage of hazardous wastes..
The operators of Quantum are seeking a RCRA operating permit and
have submitted their Part B RCRA permit application.
In May
1989, EPA began a RCRA Facility Assessment (RFA) of the Quantum
facility.
The landfill area is not included in the RFA nor the
RCRA Part B permit application.
The DAC area is included in the
permit application and, except for the truck loading and
unloading area, it is included in the RFA.
Additional activities
using RCRA authority may be necessary at the site, including a
RCRA Facility Investigation, corrective action, and possibly a
RCRA operating permit.
The Quantum facility is also regulated by the IDNR in
accordance with state laws and the Clean Water Act.
Quantum has
a National Pollution Discharge Elimination System (NPDES) Permit
for the onsite wastewater treatment plant discharge.
Quantum
:
-------
. 8
also has spill prevention and control plans for onsite storage
~
tanks containing hazardous materials.
Quantum, Getty and ACC are all potentially responsible
parties under CERCLA.
Although these companies have all
vOluntarily cooperated with EPA, the EPA has not sent special
notice letters to the PRPs for negotiations pursuant to section
122 of CERCLA, 42 U.S.C. ~9622.
1.3
SCOPE AND ROLE OF OPERABLE UNIT
The selected remedial action ground water operable unit
initiates the remediation of the ground water in the landfill and.
DAC areas of the site.
Ground water remediation is necessary
because it is contaminated with the BTEX, PAH, and chlorinated
hydrocarbons at levels which exceed public health and
environmental standards and criteria.
This operable unit
cor.prises the extraction and treatment of the ground water
contamination plumes as well as some ground water source control.
Ground water source control consists of the extraction of free
oil from some of the wells and placement of some of the
extraction wells in the landfill overburden to extract the
contaminated ground water before it migrates throughout the
plume.
Although the RIfFS report submitted by the PRPs presents
data and remedial alternatives for soils, wastes and ground
water, EPA has determined that the data and alternatives are
-------
9
insufficient for selection of a remedy for the soils and wastes
or for the final ground water remedy.
The RI/FS and the Focused
Feasibility Report present sufficient information regarding the
ground water contamination in the DAC and landfill areas for the
EPA to select this operable unit remedial action to begin cleanup
of the contaminated ground water at the site.
".
The purpose of this operable unit remedial action is to
mitigate the movement of the contaminated ground water from this
. site and to permanently treat, destroy and dispose of
contaminants found in these ground water plumes.
Also, this
operable unit should protect the nearby downgradient private
drinking water wells from these contaminated plumes prior to
implementation of the final remedial action for this site.
Additional remedial action operable units will be necessary to
complete the cleanup of this site to protect human health and the
environment from the other areas of contamination at this site,
which include, but may not be limited to, the contaminated soil,
wastes or debris and hazardous substances found at or near the
fill, the DAC area or other areas at this site.
This
op(~able unit remedial action will be consistent with future
operable units and the final remedy.
1.4
COMMUNITY RELATIONS HISTORY
As required by section 113(k) (2) (B) of CERCLA, 42 V.S.C.
Section 9613(k) (2) (B), the Proposed Plan, RI/FS Report, Focused
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10
Feasibility Study, and the administrative record were released to
the public in July ~.989.
The documents were made available to
the public in the information repositories at the Camanche and
Clinton, Iowa Public Libraries and the EPA Region VII Library in
Kansas City, Kansas.
The notice of availability for these
documents was published in the Clinton Herald on JUlY:24, 1989.
A public comment period was held from July 24, 1989, through
August 23, 1989.
interviews and preparation of a Community Relations Plan, were
Community relations activities, including
completed on August 11, 1989.
A public meeting was held on
August 14, 1989, to discuss the Proposed Plan, Focused
Feasibility Study, and the RI/FS documents.
EPA's response to
the comments received during this period is included in the
Responsiveness Summary, which is part of this Record of Decision.
1.5
SITE CHARACTERISTICS
Information regarding the site characteristics is available
in the RI/FS report prepared by the PRPs and in the Hydrogeologic
Assessment Report, prepared by Jacobs Engineering for the EPA as
well as other documents in the administrative record.
These
documents form the basis for the following summary discussion.
A.
GeoloQY/Hvdroaeoloqy
The Chemplex site is covered by surficial soils that consist
of a heterogeneous mixture of clays, silts, and gravel with
discontinuous sand lenses.
The soils are a result of former
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11
glacial activity and are known as glacial till.
The RI/FS report
refers to these soils as the overburden.
The overburden ranges
in thickness from a few feet to an excess of 100 feet.
The overburden is underlain by bedrock that is believed to
be the Anamosa formation of the Gower dolomite.
The bedrock
surface is typically weathered and fractured for several feet and
is underlain by a more competent bedrock.
Ground water occurs in both the overburden and the bedrock.
The ground water flow direction at the site appears to be toward
the southwest.
In the landfill overburden, a ground water
mounding effect appears to be causing flow toward the north and
east.
The mounding effect is causing ground water to move
radially from the center of the landfill.
In addition, the
overburden is recharging the bedrock ground water.
The ground
waters in the overburden and bedrock appear to be in hydraulic
communication, meaning that the overburden and the bedrock ground
water intermix.
B.
Soils/Wastes
Various waste streams from the polyethylene plant were
disposed of in the landfill from approximately 1968 to 1978,
including carbonate sludge, black oily sludge, off-specification
polyethylene and construction debris.
A considerable amount of
this waste is located at or below the ground water table in
various portions of the landfill.
As a result, concentrations of
BTEX have been detected as high as 8644 milligrams per kilogram
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12
(mg/kg) or parts per million (ppm), PAHs as high as 5309 ppm, and
tetrachloroethylene as high as 100 ppm.
The sources of soil contamination in the DAC area appear to
be spillage of DAC product in the storage and truck loading area
and from the storage of wastewater treatment sludges in the
previo~s basin and polishing basin areas.
Although spill control
measures, including paving, sump collection, and a berm around
the DAC tank, have been implemented in the truck loading area and
sludges were removed from the previous and polishing basins,
contaminated soils remain and ground water contaminant plumes
emanate from these areas.
BTEX and PAHs were detected in the
soil in the storage and truck loading area at maximum
concentrations of 2198 ppm and 1267 ppm respectively.
soil
contamination is suspected in the previous basin, but has not yet
been confirmed because the basin was backfilled when sludges were
removed in 1987.
It should be noted that additional site characterization, as
well as treatability testing, will be required for the soils,
wastes and debris in both the landfill and DAC areas prior to
selection of a remedial action to cleanup the soils, wastes and
debris.
Therefore, the soils, wastes and debris will be
addressed in a subsequent operable unit RI/FS and will not be
discussed further in this ROD.
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13
Ground Water
c.
In the landfill area, a mounding effect in the overburden
-
ground water appears to have resulted in plumes of contaminated
ground water flowing to the north and east from the landfill area
prior to recharging the underly.ing bedrock ground water.
The
highest concentrations of contaminants detected in th~ landfill
overburden ground water plumes were 8600 micrograms per liter
(ug/l) or parts per billion (ppb) BTEX, 470 ppb PAHs, and 60 ppb
. tetrachloroethylene (chlorinated hydrocarbon).
This shallow
aquifer may be periodically discharging to the small surface
stream located west of the site.
Tetrachloroethylene has been
detected in this surface water stream at a concentration of
198 ppb, thus su~;esting that this aquifer is contaminated with
tetrachloroethylene.
The highest concentration of contaminants in the landfill
ground water is at the overburden/bedrock interphase in an area
along the southwest border of the landfill.
The concentrations
of contaminants in this area are 96,400 ppb BTEX and 1,821 ppb
PAHs.
Ground water in the bedrock aquifer beneath the landfill has
been investigated in four different zones, designated as the A,
B, C and D zones representing different well screen intervals
(depths) of the bedrock aquifer.
See Table 1 for more details
regarding well screen intervals and the monitoring wells involved
in each zone.
As illustrated on Figures 1-2 through 1-5, a
~
-------
TABLE 1
GROUPING OF BEDROCK MONITORING WELLS
BY SCREENED INTERVAL-
Shallow Bedrock Zone A (Screened elevations 598 to 629 ft. MSL)
MW-2B
MW-5C
MW-9B
MW-IOB
MW-IIB
MW-12B
MW-12C
MW-19B
MW-20B
MW121B
Intermediate Bedrock Zone B (Screened elevations 567 to 598 ft. MSL)
MW-2C
MW-9C
MW-IOC
MW-IIC
MW-13B
MW-17B
MW-18B
MW-19C
MW-21C
Deep Bedrock Zone C (Screened elevations 522 to 555 ft. MSL)
MW-13C
MW-17C
MW-18C
MW-19D
MW-20C
MW-21D
Deepest Bedrock Zone D (Screened elevations 484 to 520 ft. MSL)
MW-13D
MW-17D
MW-18D
MW-20D
-------
,.,'*-
~
,p5i
O~
1''''
~#
~
~
I
~
o
POlI9HINO
lIAS..
~_.......................,
t MW-2tB t
. t NOBTEIC ~
. .~ NOPAH ~
~..........................~
o
I
200
400
I
Sc818 In Feet
LEGEND
MW-2
. Bedrock wen
t'::J RI Resuhs
t::J EPA Resuns
~.....................,..,
~ MW-IIB ~
~ NOBTEIC ~
~ NOPAH ..
,.....................~
.
,...,...,............~
~ MW.2B ~
~ 30.325 BTEIC ~
~ 1105 OTHER VOC ~
/:
/
/
z-- .
I
. .
Note: Wells MW-21 B and MW-20 Sampled In Phase II. All other Wells Sa~led In Phase I. Concentrations Reported In PPB.
Phase I Results Are Averages 01 Two Sar11>lIng Rounds BTEX= Benzene, Toluene, Ethylbenzene, Xylene.
PMh Polynuclear Aromatic Hydrocarbons. VOC= Volatile Organic CO"1>Ounds. DNA = Base NeutraVAcId Extractable Compounds.
r..... Of': J8I'1"'"
TOTAL n IN( 'F.NTR A 1l( INS OF COMPOUNDS DETECTED IN SHALLOW
8EDROCK Wl.ILC; I.ONI~ A. LANDFILL AREA
SlTE_;
CHEMPLEX srrn
CLIN1UN,IA
BJR
DATE: Sn189
~MI
IN;
CHECkED
IN;
DK
DAn: Sn189
-
~NO
1-2
-------
o
/
/
I
~
..
~
~
I
~
POlISHNJ
BASIN
fI"''''''''''''''''
. ~ UW-2IC ~
t NOB~X ~
~ NOPAH !
'-.."...........,..
o
I
200
400
I
LEGEND
Scale In Feet
UW.2
. Bedrock wen
l',:'1 RI Resuhs
t::J EPA Resuhs
Note: Wells MW-13B, MW-178, MW-18B And MW-21C Sa"1Jled In Phase II. All Other Wens Sa"1Jled In Phase I. Concentrations
Reported In PPB. Phase I Results Are Averages of Two Sampling Rounds BTEX= Benzene, Toluene, Ethylbenzene, Xylene.
PAH~ Polynuclear Aromatic Hydrocarbons. VOC~ Volatile Organic COlf1X)unds. BNA = Base NeutraVAcId Extractable Compounds.
CHEMPLEX SITE
CUNlUN,1A
IIRA-
BY
SIR
om: sn 189
'1CU1E NO.
,1CU1E 1J[3C~
roT AL CONCENTRA 110NS Of COMPOUNDS DETECTED IN INTERMEDIATE
BEDROCK WEW . ZONE B.I..ANDRlL AREA
!II1E-
1-3
c.-eKED
BY
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om Sn189
-------
~
~
I
C-"""""""~
. ~ MW.2ID ~
~ M> 91£1( ~
I M>PAH !
,",...,...................
o
lANDfill
POlISHt«J
BASIN
o
I
200
400
I
LEGEND
Seale In Feet
":2 Bedrock Wen
~':.J RI Resuns
t::J EPA Resuns
Note: All Deep Bedrock Wells Sampled In Second Round 01 Phase II. Concentrations Reported In PPB.
BTEX:o Benzene, Toluene, Ethylbenzene, Xylene. PAH:I Polynuclear Aromatic Hydrocarbons.
VOC:o Volatile Organic Corf1)Ounds. DNA. Base NeutraVAcId Extractable Compounds.
f_DE~~
lUTAL CONCEm'RAll0NS Of COMPOUNDS DETECTED IN DEEP
BEDROCK WElLS. 7nNE C, L6.NDRLL AREA
SlTE-
DRA-
ftY-
CIIEMPLEX SITE
CUNlUN, IA
CH£CI(fO
BY.
./
./
I
Z
I
...
BIR
DK
o.TE: 8(7/89
f_HO
0.T£: 8(7/89
1-4
-------
fO" Of""''''''''
MW-I70
NO 81U
. NO PAH
~
I
o
l'a.19HINO
BAS"
o
I
200
400
I
Scale In Feet
LEGEND
MW-2
. Bedrock Wen
Note: All Wens Saff1)led In Phase II. Concentrations Reported In PPB.
BTEX= Benzene, Toluene, Ethylbenzene, Xylene.
PAH= Polynuclear Aromatic Hydrocarbons.
TOTAL ('t IN( TN11{A TI( )NS OP AN(lfRPR(JI(f COMPOUNDS DETECTED IN DEE
REDROCK wn L~ lAIN!: U. LANDnlL AREA
lANDFU
SITE -
DJIA-
8.,
CHECKED
IIY
CHEMPLEX SITE
CLINTON,IA
/
/
I
f
....
BJR
OK
DATE: Rn189
flGU!( NO.
DATE: Sn189
1-5
~
I
-------
14
.-;number of contaminant plumes are emanating from the landfill area
in all zones.
The highest concentrations of contaminants
associated with these plumes were detected in the shallow and
intermediate bedrock 'zones.
These contaminant concentrations are
52,880 ppb chlorinated hydrocarbons, and 33,883 ppb BTEX and
1,700 ppb PAHs, respectively.
In the deeper bedrock zones, these
contaminants are considerably lower in concentration.
The closest residential drinking water wells southwest of
. the facility were sampled-and analyzed because these residences
are located downgradient of the site and would be the first
affected by movement of the plume.
The analyses indicates that
at this time these water wells are not contaminated from the
migration of contaminants from the site.
At this time, the depth
at which these residential wells draw water is unknown, but this
is to be determined during further RI/FS activities.
In the DAC area the ground water plume of contamination in
the overburden also appears to be migrating to the southwest.
The highest concentrations of contaminants detected in the DAC
overburden plume are 249,000 ppb BTEX and 13,829 ppb PAHs.
This
plume of ground water contamination is fairly well defined as
described in the RI/FS.
In the DAC area, one monitoring well was installed into the
bedrock ground water.
Analysis of samples taken from monitoring
wells showed concentrations of 650 ug/l for benzene.
The Maximum
Contaminant Level (MCL) established by the Safe Drinking Water
-------
15
Act for benzene is 5 ug/l and the level established by the state
of Iowa is 1 ug/l for benzene.
Therefore,_ground water
remediation is required in the bedrock as well as the overburden.
However, the plume of" contamination in the DAC bedrock ground
water is not yet defined.
It should be noted that since the vertical and horizontal
extent of contamination in the ground water is not yet completely
defined for either the landfill or DAC areas, further
hydrogeologic and chemical data will need to be collected during
remedial design to delineate the extent of contamination.
EPA
believes, however, that there is sufficient information to select
a remedy for the ground water operable unit at this time, since
information is available regarding ground water characteristics,
such as the rate and direction of ground water flow, and the
RI/FS data which initially identifies the nature and general
extent of certain plumes of contamination.
1.6
SUMMARY OF SITE RISKS
The PRPs prepared and submitted to EPA a "Draft Endangerment
Assessment for the Chemplex Site" for the purpose of evaluating
the existing and potential impacts of the site on human health
and the environment.
The draft Endangerment Assessment (EA)
discusses contaminants of concern, adverse health effects, and
exposure pathways.
It should be noted that the draft EA is
incomplete for three basic reasons:
1) the draft EA does not
-------
16
adequat0ly address the ground water pathway; 2) some pathways
were not completely addressed based on the insufficient data that
was collected during the RI/FS phase to delineate the total
aereal and vertical eXtent of contamination; and 3) the draft EA
does not adequately address volatile organic exposure via the air
pathway.
The EPA provided numerous comments to the PRPs
regarding the deficiencies of the draft EA and these comments are
available in the administrative record.
As an addition to the
. draft EA submitted by the PRPs, EPA has included information in
the administrative record and this record of decision regarding
risks of exposure to the ground water.
The following information'
summarizes the potential impacts of contamination at the site on
human health and the environment.
Further information on these
impacts and risks is available in the draft EA, the Remedial
Investigation and the administrative record.
Contaminant Identification
A.
In order to allow for a realistic estimation of potential
risk where a number of chemicals have been detected at the site,
it is often necessary to select a list of indicator chemicals to
conduct the detailed analysis of the risk assessment.
Based on
existing data for the contaminants found at the site and the most
toxic contaminants detected on the site, the indicator compounds
selected for the risk assessment included:
antimony, benzene,
chloroform, 1,2-dichloroethylene, ethyl benzene, carcinogenic and
-------
17
noncarcinogenic polynuclear aromatic hydrocarbons (PAHs),
styrene, tetrachloroethylene, trichloroethylene and toluene.
B.
Human Health Exposure Assessment
The draft EA identified the following exposure pathways as
being the most likely exposure scenarios and conducted site-
specific analyses of carcinogenic and noncarcinogenic"effects:
inhalation of fugitive dust in the CAC area by onsite workers;
inadvertent ingestion of, and dermal contact with, surface soil
in the CAC area by onsite workers; and dermal exposure to surface
water in the intermittent tributary to Rock Creek by children
visiting the tributary.
The draft EA erroneously did not
consider the ingestion of ground water as a potential exposure
pathway.
contaminant concentrations in the ground water plumes
emanating from the landfill and CAC areas substantially exceed
federal criteria for the protection of human health from
ingestion of contaminated water.
Table 1-4 compares the maximum
concentration of contaminants detected in these plumes with the
Maximum Contaminant Levels (MCLs) and proposed Maximum
Contaminant Levels and other water quality criteria.
This
comparison indicates that these plumes of contamination present a
substantial risk to human health from the ingestion of the
contaminated ground water.
Existing downgradient private
drinking water wells and any future wells installed should be
protected from this potential risk.
The Agency for Toxic
Substances and Disease Registry (ATSDR) recommends that ground
-------
TABLE 1-4
GROUND WATER CONCENTRATIONS (ug/l) OF CONTAMINANTS
OBSERVED IN MONITORING WELLS
Maximum in Maximum
Landfill Area in DAC Area criteria
Benzene 96,700 244,000 Sa
Ethylbenzene 2,780 1,1S0 700b
Polynuclear Aromatic Hydrocarbons
(PAHs) 1,821 13,800 o. 20c. .
Tetrachloroethylene 50,000 190 5b
Toluene 10,300 27,600 2000b
Trichloroethylene 3,700 52 Sa
1,2-Dichloroethylene 3,800 100 100d
a Maximum contaminant Level (MCL) established by the Safe Drinking Water Act.
b Proposed Maximum contaminant Level established by the Safe Drinking Water Act.
c. Criteria from the 1970 World Health organization European Standards for Drinking
Water based on a composite analysis of six PAHs. Reference: Handbook of Toxic
and Hazardous Chemicals and Carcinogens: Second Edition by Marshall sittig.
. .
d U.s. EPA Office of Drinking Water Health Advisory Level.(HAL).
-------
18
water use be restricted in the vicinity of these plumes until the
ground water is remediated.
An assessment was performed to evaluate noncarcinogenic and
carcinogenic potential adverse effects to human health due to
exposure to the indicator compounds through various media.
Although not evaluated in the draft EA, human health risks have
since been calculated for the ground water pathway using
concentrations at the downgradient portion of the plume and the
. results are presented herein.
Supporting calculations can be
found in a technical memorandum which is part of the
administrative record.
The title of this memorandum is Chemplex .
Facility Site, Clinton, Iowa; Endangerment Assessment of
Potential Ground Water Exposure, dated September 22, 1989, by
Jacobs Engineering for EPA.
The evaluation of noncarcinogenic risks included calculation
of the hazard index (HI) for each media.
The HI incorporates a
dose response assessment for exposure to individual site-specific
compounds.
The daily intake (DI) or estimated dose is calculated
based on ingestion or inhalation routes of exposure to the
contaminated soil or ground water.
The DI is then related to the
established reference dose (RfD) which is defined as an estimate
of a daily exposure that is likely to result in no appreciable
risk of deleterious effects during a lifetime. The total HI is a
summation of the DI divided by the RfD (DI/RfD) which is intended
to provide a measure of possible effects of human exposure to
-------
19
toxic chemicals.
An HI of one (1) or greater indicates the
-.
possibility of adverse noncarcinogenic health effects.
Carcinogenic risks were assessed by estimating.the excess
lifetime r::'. ~.cer probability (the risk above background).
This
estir~~e was calculated by multiplying the estimated exposure
dose by the chemical-specific cancer potency factor (CPF).
The
CPF is established for individual carcinogenic compounds.
The
CPF are then related to site-specific dose-response and exposure
. routes.
The acceptable range for excess lifetime cancer
probabilities is generally considered by EPA to be from 1 x 10-4
to 1 x 10-7 (1 in 10,000 to 1 in 10,000,000).
The draft EA calculations for noncarcinogenic risks through
the dermal, inhalation and ingestion routes of workers' exposure
to DAC soils is an estimated HI of 2.4 x 10-2. Risks of
children's dermal expos~re to surface water is an estimated HI of
-6
2.19 x 10 .
The calculated HIs for these routes are less than
one (1), which indicates that there would not be an unacceptable
noncarcinogenic risk to human health based on available site
contam~ 1nt data for the specified routes.
The
:r values for the ground water pathway for ingestion of
the landf~
area bedrock aquifer for PCE, TCE, 1,2-dichloro-
ethylene and total PAHs were calculated to be 13.6, 0.07, 1.1,
and 5.1, respectively.
The HI value for the DAC area overburden
aquifer for total PAHs was calculated to be 41.2.
These values,
with the exception of the TCE value in the landfill bedrock, are
;
-------
. 20
greater than one (1) and are unacceptable for noncarcinogenic
health effects.
Noncarcinogenic risk characterization (HI
values) for benzene were not calculated because of its Class A
carcinogenic classification.
The calculated lifetime cancer risks associated with
workers' exposure to DAC soils was estimated to be 4.13 x 10-7
and was estimated to be 2.68 x 10-8 for children's exposure to
surface water.
These levels are below the 1 x 10-4 to 1 x 10-7
risk range, a level considered acceptable by EPA standards.
Excess lifetime cancer risk values for the ground water pathway
for the landfill area bedrock aquifer for benzene, PCE and TCE
were calculated to be 4.9 x 10-2, 1.4 x 10-2, and 2.4 x 10-4,
respectively.
Values for the DAC area overburden aquifer for
benzene was calculated to be 2.9 x 10-2.
The value for the DAC
area bedrock aquifer for benzene was calculated to be 3.2 x 10-4.
These values are greater than the 1 x 10-4 to 1 x 10-7 range and
are considered unacceptable by EPA standards for carcinogenic
health affects.
Analytical data obtained for various media during upcoming
field activities may change calculated noncarcinogenic and/or
carcinogenic risk because additional analytical data may yield
different DI values and, thus, different HIs.
The air pathway was not adequately addressed in the draft
EA.
Ambient air monitoring may be conducted during future
remedial investigations.
-------
. 21
C.
Ecoloqical EXDosure Assessment
The ecological risks for terrestrial a~d aquatic organisms
were calculated by means of the toxicity quotient mathod.
The
toxicity quotient method compares an estimated environmental
concentration (EEC) of an indicator chemical to an
ecotoxicological benchmark (BC).
The EEC is divided by the BC to
obtain the toxicity quotient for the exposure of a given species
to a given chemical as follows:
toxicity quotient = EEC (uq/l)
(unitless) BC (ug/l)
Results of the toxicity quotient method are considered to be "no'
concern" if the ratio is less than 0.1, "possible concern" if the
ratio falls within the range of 0.1 to 10, and "high concern" if
the ratio is greater than 10.
The toxicity quotient was calculated for rats, mice, deer,
and mallard ducks consuming food items assumed to be contaminated
with the estimated soil concentration of noncarcinogenic PAR
(naphthalene).
It was concluded from these results that the
potential for acute or chronic effects to terrestrial species
from the ingestion of edible vegetation containing
noncarcinogenic PAR is of "no concern".
The toxicity quotient
was also calculated for aquatic species exposed to chemical
concentrations in the intermittent stream.
It was concluded from
these results that the potential for chronic effects to aquatic
species from exposure to benzene, ethylbenzene, toluene and
tetrachlorethylene (PCE) are of "no concern".
The estimated
-------
22
toxicity quotient for naphthalene is in the lower range of the
"possible concern" category.
However, sinCe naphthalene was not
actually detected in the stream, a concentration of ~ of the
detection limit was used to calculate the toxicity quotient.
This is a conservative assumption and, therefore, it is
anticipated that the actual toxicity quotient would be lower than
the calculated value.
It should also be noted that the concentrations of
contaminants in the one surface water stream sample of the
tributary to Rock Creek did not detect any contaminants that
exceeded any EPA Water Quality Criteria for Protection of Aquatic
Life.
Based on available data, it does not appear that
terrestrial and aquatic organisms are adversely impacted by the
site.
It should also be noted that the overburden ground water
periodically discharges to this intermittent stream.
The draft
EA did not consider periodic exposures of the aquatic life to the
ground water in this stream.
The next operable unit remedial
investigation may include additional sampling of this stream and
a reevaluation of the risks to aquatic life.
This Upper Mississippi River Wildlife Refuge is located just
a few miles from the site and bald eagles (an endangered species)
have been seen at this refuge.
The current data indicates that
the contamination from this site does not affect this wildlife
refuge.
While the threat of contamination from this site
reaching this refuge was not considered in the draft EA, such a
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23
threat should be evaluated in the next operable unit.
In
addition, the potential impacts on, or threats to, this wildlife
refuge must be considered during any response activ{ties at this
site, particularly if the second operable unit RI/FS or remedial
actions might influence Rock Creek or the NPDES discharge.
~
2.0
ALTERNATIVES EVALUATED
Remedial alternatives were screened based on effectiveness,
implementability and relative capital, operations, and
maintenance costs.
containment and in situ treatment of ground
water were eliminated because of implementability and
effectiveness limitations as detailed in the RI/FS submitted by
the PRPs.
The EPA evaluated three alternatives in detail in the
Focused Feasibility Study for this operable unit.
These
alternatives were 1) no action, 2) extraction and treatment at
the existing onsite treatment plant with pretreatment, and
3) extraction and treatment at a new onsite wastewater treatment
plant.
A description of these alternatives is provided below.
2.1
ALTERNATIVE 1 - NO ACTION
The no action alternative would allow site conditions to
remain as they currently exist.
Evaluation of the no action
alternative is required by the National Contingency Plan (NCP)
-------
, 24
and also provides a baseline for comparison with the other
alternatives.
2.2
ALTERNATIVE 2 - EXTRACTION AND TREATMENT AT EXISTING WASTE
WATER TREATMENT PLANT WITH PRETREATMENT
Alternative 2 provides for the extraction of the
contaminated ground water in the overburden and in the deep
aquifers at both the landfill and DAC areas.
The contaminated
ground water would be extracted at a rate of approximately 140
gallons per minute (gpm). 'This extracted ground water would be
pumped to a pretreatment unit (to be built for this action) and
then to the existing wastewater treatment plant operated by
Quantum.
After treatment, the water would be discharged via the
Quantum facility NPDES permitted outfall to the Mississippi
River.
Spent carbon generated at the pretreatment unit will
require special handling for disposal as a hazardous waste.
Landfill Area
In order to control the plume of contamination in the
landfill area, it is anticipated that approximately 70 gallons
per minute (gpm) extraction capacity would be required in the
overburden and bedrock aquifers.
The final extraction capacity
and placement of extraction wells in the two aquifers will be
determined during the remedial design phase.
DAC Area
In the DAC Area, an existing ground water recovery system
consisting of a collection trench, wick wells and extraction
-------
25
wells is in place and operates to extract contaminated ground
water from the overburden aquifer.
Approximately 20 gpm is
extracted using this existing system.
Alternative 2 includes an
evaluation of the effectiveness of this existing recovery system
for the overburden aquifer and delineation of the plume of
contamination in the bedrock aquifer.
It is anticipated that an
additional extraction capacity of 50 gpm in the bedrock and
overburden aquifers may be required to control the plume of
contamination in the DAC Area.
The remedial design of the Alternative 2 would include
collection of additional hydrogeologic data to determine the
final number, locations and capacity of the extraction wells to
meet the objective of initial control over the plumes of
contamination.
Treatment
The existing onsite wastewater treatment facility with a
pretreatment unit would be utilized to treat the extracted ground
water from the two areas.
The existing treatment facility
currently has a permitted NPDES discharge to the Mississippi
River.
The existing wastewater treatment plant is a biological
activated sludge plant capable of treating the chlorinated
hydrocarbons, PAH compounds and BTEX compounds, which are
contaminants of concern for the site.
Based on currently available data, it is appropriate to use
pretreatment units such as an air stripper using carbon
~
-------
26
absorption overhead treatment or an ultraviolet/oxidation system.
These alternatives are discussed in detai~ in the Focused
Feasibility study report.
The final pretreatment option would be
selected during the design phase.
The pretreatment unit would be
designed to remove the chlorinated hydrocarbons and other
volatile organics, such as benzene, from the ground water
allowing for effective treatment of remaining ground water
contaminants at the existing plant.
Ground water would continue
to be extracted and treated until the ground water achieves the
applicable or relevant and appropriate cleanup criteria.
These
criteria are identified in Table 5-1, Section 5.
This treatment
system is flexible and may be modified by subsequent response
actions at this site.
The EPA has considered treatment utilizing the existing
wastewater treatment facility without pretreatment as an
alternative.
However, based on currently available data, it
appears that the wastewater treatment facility without
pretreatment may not be able to achieve compliance with all of
the applicable or relevant and appropriate requirements (ARARS).
In particular, it appears that without pretreatment, the NPDES
discharge limits for several contaminants would be exceeded with
this alternative.
Such an alternative would also allow
unacceptable levels of chlorinated hydrocarbons and other
volatile organic compounds such as benzene, to be released in the
air in the area of the wastewater treatment facility.
Therefore,
-------
27
the Agency prefers the selected remedy which uses the existing
plant with pretreatment.
The estimated capital cost for this remedy is approximately
$552,000.
The estimated annual operation and maintenance cost
for this alternative would be approximately $219,600 and total
~
$2,070,pOO over thirty years.
The estimated total present value
of this alternative is $2,622,000.
The implementation time for
this remedy would be approximately 16 months.
2.3
ALTERNATIVE 3 - EXTRACTION AND TREATMENT AT A NEW WASTEWATER
TREATMENT PLANT
This alternative would require the same ground water
extraction system as Alternative 2.
However, instead of treating
the ground water at the existing onsite wastewater treatment
plant, Alternative 3 requires the design and construction of a
new wastewater treatment plant to treat the ground water.
Based
on available information regarding the physical and chemical
characteristics of the aquifers, an acceptable treatment system
for this contaminated ground water would consist of an air
stripper followed by a biological sequencing batch reactor
followed by a carbon bed polishing unit.
This treatment system
may be modified or changed during the design phase.
The estimated capital cost of this alternative is
$1,140,000.
The estimated annual operation and maintenance cost
is approximately $353,200 and total $3,329,600 over thirty years.
-------
" 28
The estimated total present value of this alternative is
$4,469,600.
The implementation time for this remedy is
approximately 20 months.
3.0
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The selected remedy for the landfill and DAC areas initial
ground water remediation is Alternative 2.
As described above,
this alternative involves extraction of ground water from the
" landfill and DAC areas and treatment of the ground water at the
existing onsite wastewater treatment plant with pretreatment.
Based on currently available information, this alternative
provides the best balance of tradeoffs with respect to the nine
criteria that EPA uses to evaluate remedial action alternatives.
This section provides a summary of each criteria and an analysis
of the alternatives under consideration for this operable unit of
the Chemplex site.
For further information on the "nine criteria,
refer to EPA Interim Final "Guidance for Conducting Remedial
Investigations and Feasibility Studies under CERCLA" dated
October 1988.
3.1
PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
Protection of human health and the environment is the
central mandate of CERCLA, as amended by SARA.
Protection is
achieved by minimizing risks posed by the site and taking action
to eliminate future unacceptable risks to human health and the
-------
29
environment through any pathway.
Each remedial alternative may
have different long-term and short-term effects on the protection
of human health and the environment.
All of the alternatives evaluated in this operable unit,
with the exception of the no ac~ion alternative, should provide
adequate protection of human health and the environment by
reducing and controlling risk through extraction and treatment of
ground water, thereby minimizing the potential for further
migration of contaminated ground water from this site.
The
extraction process will remove the contaminants from the ground
water and will therefore protect the nearby residents from
drinking contaminated ground water.
The treatment process will
permanently treat, destroy and dispose of the contaminants and
the treated ground water will be discharged to the Mississippi
River in accordance with NPDES requirements that will be
protective of human health and the environment.
3.2
COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS
Section 121(d) of CERCLA, 42 U.S.C. S9621(d), as amended,
requires that remedial actions comply with legally applicable or
relevant and appropriate requirements (ARARs) under Federal and
State laws.
All of the alternatives considered in this operable
unit, with the exception of the no action alternative, will
comply with the ARARs identified for this operable unit of the
site.
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30
The chemical-,locatio~-, and action-specific ARARs for this
remedial action are listed in Tables 5-1, 5-2, and 5-3, which are
presented in Section 5.2, Attainment of the ARARs.
Regarding the chemical-sp~cific ARARs listed on Table 5-1,
it should be noted that the Health Advisory Levels (HAL),
Negligible Risk Levels (NRLs), and Maximum contaminant Levels
(MCLs) established under the Safe Drinking Water Act are
. considered applicable requirements pursuant to rules adopted by
the state of Iowa.
Therefore, these levels are the primary
cleanup goals.
The MCLs are also considered relevant and
appropriate requirements based on EPA guidance.
Even though this
is an operable unit remedial action, treatment of the
contaminated ground water will be required until achievement of
the cleanup goals for all of the contaminated ground water found
at the site in the landfill and DAC areas.
3.3
LONG-TERM EFFECTIVENESS AND PERMANENCE
Long-term effectiveness and permanence address the ability
of a remedy to maintain reliable protection of human health and
the environment over time once cleanup goals have been met.
All of the Alternatives referenced herein, except the no
action alternative, would have equal effectiveness in providing
protection to human health and the environment.
This is because
both Alternatives 2 and 3 would have ground water extraction
systems capable of controlling the plumes in the landfill and DAC
-------
31
areas and both Alternatives would have treatment systems capable
of permanently treating, destroying and disposing of
contaminants.
3.4
REDUCTION OF TOXICITY, MOBILITY OR VOLUME
T~is evaluation criteria relates to the performance of a
technology or remedial alternative in terms of eliminating or
controlling risks posed by the toxicity, mobility, or volume of
hazardous substances.
All of the Alternatives, except the no action alternative,
provided for the reduction of toxicity, mobility or volume of
contaminants by extraction of the ground water and subsequent
treatment.
This is because the extraction system for
Alternatives 2 and 3 would effectively control the plumes of
contamination and therefore would reduce the toxicity, mobility
and volume of contaminants impacting the ground water.
The
treatment system for Alternatives 2 and 3 would then permanently
treat, destroy and dispose of contaminants.
3.5
SHORT-TERM EFFECTIVENESS
Short-term effectiveness addresses how well an alternative
is expected to perform, the time to achieve performance and the
potential adverse impacts of its implementation.
The short-term
effectiveness of the two alternatives would be essentially the
same, because the time it would take to implement the two
;
-------
32
alternatives is a difference of only 4 months and there would be
no adverse effects for the onsite workers-except for the
customary risks of construction.
3.6
IMPLEMENTABILITY
Implementability addresses how easy or difficult, feasible
or infeasible, an alternative would be to carry out from design
through construction, operation and maintenance.
The various components of Alternatives 2 and 3 are proven
technologies and materials necessary to implement them should be
readily available.
3.7
COST
CERCLA requires that EPA select the most cost-effective (not
merely the lowest cost) alternative that protects human health
and the environment and meets other requirements of the law.
The
no action alternative, which would involve no cost, was
considered in order to meet requirements of the law.
The FS
submitted by the PRPs indicates that costs would be incurred for
monitoring under the no action alternative.
since additional
operable units will be conducted and monitoring will be included,
such costs are not presently included in the no action
alternative, herein.
Total capital costs are estimated at $552,000 and
$1,400,000, for Alternatives 2 and 3 respectively.
Table 3-1,
-------
1 ABLE 3-1
COST ESTIMATES
IMPLEMENTATION
CAPITAL
COST
ANNUAL
O&M
ANNUAL
O&M
30 YEAR
PRESENT
WORTH
TOTAL
PRESENT VALUE
ALTERNATIVE TIME (A) (B) B(9.427)=C A+C
No Action 1 0 0 0 0 0
Alternative 2 16 552,000 219,600 2,070,200 2,622,200
Alternative 3 20 1,140,000 353,200 3,329,000 4,469,600
Assumptions:
Interest Rate 100/0
Number of years 30
No Major Equipment Replacement
TS4/T3-1 CM925
"
-------
. 33
herein, lists the estimated costs for each alternative evaluated.
Present worth operation and maintenance costs (at 10% discount
rate) are estimated at $2,070,000 and $3,329,600 for Alternatives
2 and 3, respectively.
The total present worth costs are,
therefore, estimated at $2,622,000 and $4,469,600 for
Alternatives 2 and 3, respectively.
These costs were taken
directly from the Focused Feasibility Study Report and are
. presented for comparative purposes.
Final costs of the selected
remedy will be developed during design.
3.8
COMMUNITY ACCEPTANCE
This evaluation criteria addresses the degree to which
members of the local community support the remedial alternatives
being evaluated.
There were no specific adverse comments from
the public related to the remedial alternatives being evaluated
or the proposed remedy.
A pUblic meeting was held on August 14, 1989, to present the
Proposed Plan and solicit public comment.
The public comment
period was from July 24, 1989, until August 23, 2989.
Significant public comments are addressed in the Responsiveness
Summary, attached to this ROD.
Other comments that were received
are also being responded to.
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34
3.9
STATE ACCEPTANCE
The state acceptance criteria addresses the concern and
degree of support that the state government has expressed
regarding the remedial alternatives being evaluated.
The state
has participated in the review Of all of the RI/FS documents and
in negotiations with the PRPs.
The state of Iowa issued a letter
of concurrence on the selected remedy dated August 3, 1989.
A
copy is attached.
4.0
THE SELECTED REMEDY
The selected remedy, Alternative 2 of the Focused
Feasibility Study, represents the best balance among the criteria
used to evaluate remedies.
The selected remedy will protect
human health and the environment, attain ARARs, be cost-
effective, and utilize permanent solutions employing treatment
technologies to the maximum extent practicable.
The selected remedy includes the following:
- Institutional controls to restrict use of ground water
until remedial actions achieve cleanup of the contaminated ground
water to required levels.
- Extraction of ground water by placement of extraction
wells in and around the plumes of contamination in the landfill
and DAC areas.
- Pretreatment of the extracted ground water, proper
disposal of pretreatment solid wastes in accordance with RCRA.
-------
. 35
- Treatment of the extracted and pretreated ground water at
the existing onsite wastewater treatment p~ant.
- Discharge of the treated ground water to the .Mississippi
River via a federally. permitted outfall in accordance with the
existing NPDES permit, or modified as necessary.
4.1
RESTRICT USE OF GROUND WATER
Since the concentrations of various contaminants
. substantially exceed human. health and environmental standards in
the plumes of ground water contamination from the site, the
Agency for Toxic Substances and Disease Registry (ATSDR)
recommends that ground water use be restricted at or near the
plumes.
The Iowa Environmental Quality Act, Iowa Code Ann.
~455B, and the Iowa Admin. Code, Chapter 38, require that routine
installation of all private water wells be permitted by IDNR or
its designee.
This authority may be used to restrict
installation of wells in the pathway of the plumes.
In addition,
the landfill is being placed on the Iowa registry of hazardous
waste sites by IDNR, which requires placing by the state of a
notice on the deed preventing sale of the landfill or change in
land use without approval by the state.
Deed restrictions are
also required for the adjacent property, under which the
contaminated ground water plumes are migrating.
Such
restrictions will be implemented by the state of Iowa or the
local government.
-------
36
4.2
EXTRACTION OF GROUND WATER
The selected remedy includes the placement of extraction
wells in the contaminated ground water plumes to control
migration.
It is anticipated that a total of approximately
140 gpm of extraction capacity will be required to control
migration of the plumes in the overburden and bedrock.~quifers of
the landfill and DAC areas.
However, the final extraction
capacity and number and placement of extraction wells will be
. determined during the Remedial Design phase.
4.3
PRETREATMENT OF EXTRACTED GROUND WATER
The selected remedy consists of a pretreatment unit which
will be designed to remove approximately 99% of the volatile
organic compounds, including chlorinated hydrocarbons and BTEX
compounds from the ground water.
A viable pretreatment system
which has been identified as the preferred design for the
selected remedy to be used for pretreatment consists of air
stripping with overhead treatment of the vapors by carbon
absorption.
The design for this type of pretreatment system
would include air dispersion modeling which would provide data to
calculate a risk assessment for air emissions from the air
stripper.
This type of pretreatment design could be utilized to
meet the objectives of pretreatment.
Solid wastes generated from
this type of pretreatment unit would be disposed in accordance
with RCRA Subtitle C requirements.
If the modeling and risk
;
-------
37
assessment indicate that overhead treatment is not required, the
design may be modified accordingly.
Additional predesign investigations are planned with an
emphasis on collection of data which may provide additional
information warranting the selection of a different pretreatment
system.
The final pretreatment system must meet the pretreatment
objectives and the nine criteria for selection of remedial
actions.
See Figure 4-1 for a schematic for the extraction,
. pretreatment, treatment, and discharge process.
4.4
TREATMENT OF THE EXTRACTED GROUND WATER
After extraction and pretreatment, the ground water will be
treated at the existing onsite wastewater treatment plant.
The
existing treatment plant is a biological activated sludge plant
which has been used extensively to treat volatile organic and
semi-volatile organic compounds, including the compounds of
concern that will remain after pretreatment.
This biological
activated sludge plant is a proven treatment technology.
contaminants remaining in the extracted ground water
following pretreatment would be diluted following addition to the
plant process wastewater stream.
Volatilization, adsorption, and
biodegradation are the mechanism by which the remainder of the
contaminants would be removed from the water to achieve the NPDES
permitted discharge levels.
The majority of contaminants
remaining following pretreatment would be the semi-volatile
-------
EXTRACTED
GROUNDWATFR
.
PRETREATED
GROUNDWATFR
(UMOVED OF
VOfATlU O.GANIC
COMPOUNDS)
GROUNDWATER
> PRETREATMENT
UNIT
EXlRACTION SYSTEM
(TYPICAL EXTRACTION WElL)
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OROUND SURFACB
---'- .
W ATP.R TABLE
W ASTEW ATER
FROM ~
POL YETIlYLENE
PLANf
EXISTING
W ASTEW ATER
TREATMENT
PLANT
..
Fi~ur(' 4-/ Schematic of Groundwater Extraction, Treatment, and Discharge Process
-
OVERBURDI!N
OVERBURDI!NJBEDROCIt
INrnRFACI!
BEDROCIt
......"..... ....".. ..
TREATED EFFLUENT
DISCHARGED IN
COMPUANCE wrrn
NPDES PERMI1TED
LEVELS
Ll!GEND
-_. OROUND SURPAaI
---. WATER TABLE
rLt OVI!RBURDI!N
E:j BEDROCIt
ifII OROUNW A TP.R FLOW
" OOtECI1ON
NOT TO SCALE
-------
38
organics, which would be biodegraded in the existing onsite
wastewater treatment plant.
The pretreatment unit in conjunction
with the existing treatment plant would achieve compliance with
current NPDES permitted effluent limitations.
D
4.5
D~SCHARGE OF TREATED GROUND WATER
The existing onsite wastewater treatment plant effluent is
discharged via an NPDES permitted release to the Mississippi
River, just upstream of the Upper Mississippi River Wildlife
Refuge.
The selected remedy requires that approximately 140 gpm
of contaminated ground water will be extracted and subsequently
treated at the existing treatment plant after pretreatment
removes the chlorinated hydrocarbons and other volatile organics,
including benzene.
Modifications to the existing permit or a new
NPDES permit may be required because of the added burden on the
wastewater treatment plant from the contaminated ground water.
The IDNR will review, monitor and determine if any modifications
or a new NPDES permit is required.
The responsible parties will
apply for such modifications, if necessary.
Based on available
data, it appears that treatment of the extracted and pretreated
contaminated ground water will achieve the effluent limitations
of the existing NPDES permit.
The selected remedy will achieve
appropriate discharge limitations in accordance with the National
Pollution Discharge Elimination System (NPDES) requirements and
will protect the nearby wildlife refuge.
Achievement of the
.
-
-------
39
NPDES requirements and protection of the wildlife refuge and the
bald eagles that visit the refuge are goals of the remedial
action for this site.
The selected remedy for this operable unit
is the initial step toward, and is consistent with, providing
protection of the wildlife refuge.
5.0
STATUTORY DETERMINATIONS
The selected remedy satisfies the statutory requirements for
the degree of cleanup as specified by CERCLA, by extraction and
treatment which will permanently treat, destroy, and dispose of
ground water contaminants.
Section 121 of CERCLA, 42 U.S.C.
Section 9621, states that the selected remedy shall:
1)
2)
Be protective of human health and the environment;
Attain ARARs (or provide evidence showing ARARs cannot
be attained);
3)
4)
Be cost-effective; and
Utilize permanent solutions and alternative treatment
technologies or resource recovery technologies to the maximum
extent practicable.
The pretreatment system and the biological
activated sludge treatment system are permanent treatment
technologies that are capable of treating the volatile organic
compounds and polynuclear aromatic hydrocarbons in the ground
water.
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40
5.1
PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
The selected remedy will provide protection of human health
and the environment by extraction, pretreatment and treatment of
contaminated ground water from the site.
The concentrations of
various contaminants in the ground water presently exceed human
health and environmental standards and criteria.
The'extraction
of this contaminated ground water initiates control over the
migration of the contaminated ground water plumes.
Such control
will reduce the potential .for these plumes to reach downgradient
private drinking water wells and will reduce the potential
discharge of contaminated ground water to surface waters, thus,
protecting aquatic life and wildlife in the vicinity of the site.
The selected remedy will discharge the ground water to the
Mississippi River at concentrations of contaminants that will be
in accordance with the NPDES requirements and will protect the
river's aquatic life as well as the downstream wildlife area.
5.2
ATTAINMENT OF THE ARARs
The selected remedy will comply with the chemical-specific
Federal and State ARARs for cleanup levels to be attained in the
ground water at the site or migrating therefrom.
The remedy will
be engineered and implemented to meet location-specific and
action-specific ARARs.
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41
Chemical-Specific ARARs
The ROD describes the chemical-specific ARARs that this
operable unit must achieve in the long-term for remediation of
the contaminated ground water in the landfill and DAC areas.
Although this is an operable unit remedial action, chemical-
specific ARARs are appropriately identified at this time because
this remedy may become the final ground water remedy for these
areas.
The chemical-specific ARARs for this operable unit are
identified in Table 5-1. These ARARs were developed to protect
the shallow ground water from further contamination due to BTEX,
PAHs and chlorinated hydrocarbons, which emanate from the site.
The ground water must be protected because it is a Class II
aquifer, which is a current and potential drinking water source.
Table 5-1, Chemical-Specific ARARs, includes the
requirements of the Iowa rules for determining cleanup actions at
hazardous waste sites, Iowa Administrative Code, Chapter 133
(455B, 455E). These rules are legally applicable to the remedial
action to be performed at the Chemplex site for this operable
unit. The Iowa Administrative Code, Section 133.2, defines the
hierachy of cleanup action levels for remediation of contaminated
ground water in Iowa. This hierachy establishes the EPA Health
Advisory Levels (HAL) for a contaminant will be the cleanup
action level if a HAL exists; if not, the EPA negligible risk
-------
TABLE 5-1
CHEMICAL-SPECIFIC ARARs
CWA-Ambient Water
CWA - Water Quality Criteria Quality/Protection
Proleclion 0' Human Heallh 0' Aqualic li'e
SDWA Proposed Water & Fish Fish (only) Freshwater
HAL NRL SDWA MCls MCls Ingestion Consumplion Acute/Chronic
(ugJl) (ugll) (ugJl) (ugJl) (ugJl) (ugJl) (ugJl)
BTEX Benzene . 1 5 . 0.66 . 5,3001.
Compounds
Toluene 2.000 . . 2,000 14,000 420,000 17,000/.
Ethyl benzene 700 . . 700 1,400 3,300 32,000/.
Xylenes . . 10,000 . . .
10 . 000
Chlorinaled Tetrachloroethylene 10 . . 5 0.8 8.9 5,200/840
Hydrocarbon
Compounds Trichloroethylene . 3 5 2.7 81 45,000121,000
1,1- Dichloroethylene 7 * 7 3,100 . 11,0001.
1,2-Dichloroethylene 70 . . 100 . . .
Polynuclear Anthracene . . . . . . .
Aromatic
Hydrocarbon Fluorene . . . . . . .
Compounds
(PAH) Naphthalene . . . . . . .
Phenanthrene . . . . . . .
Pyrene . . . . . . .
HAL - Office 0' Drinking Water li'ellme Heallh Advisory level
NRl - Negligible Risk level 'or excess 1.ooE-06 liIelime cancer risk
SDWA - Sa'e Drinking Water Ar:t MCl - Maximum Contaminant level CWA - Clean Water Act
. Standards not specified lor compound
Other Chemical-Specific ARARs are listed below.
State
Iowa Administrative Code Secllon 61.2(2), Antidegradation Policy: The qualily 0' the walers 0' the state should not degrade.
Cleanup level hlerachy 01 HAL, NRL, and MCl.
TS5:RDTB5-1
-------
. 42
level (NRL) for carcinogens shall be the cleanup level if one
exists; if no HAL or NRL exist, then the EPA enforceable maximum
contaminant level (MCL), established pursuant to the Safe
Drinking Water Act (SWDA), shall be the action level.
If no HAL,
NRL or MCL exist, the action level will be established on a
case-by-case basis using EPA recommended guidelines arid
recognized experts.
Table 5-1 identifies the existing HAL, NRL,
and MCL for the contaminants of concern at the Chemplex site.
In
accordance with this Iowa rule, the HALs for toluene,
ethylbenzene, xylene, l,l-dichloroethylene and 1,2-dichloroethylene
are the applicable actions levels for cleanup of the contaminated
ground water for these contaminants.
The NRLs are the applicable
cleanup action levels for benzene and trichloroethylene.
Although a HAL exists for tetrachloroethylene, it is not
applicable because the proposed MCL is more stringent than the
HAL.
Because of this anomaly, the HAL for tetrachloroethylene is
relevant and appropriate and the proposed MCL is to be considered
in implementation of this remedial action.
In the event that attainment of the HALs or NRLs is not
practical, the MCLs and proposed MCLs may become the alternative
cleanup levels for anyone of the contaminants.
This
substitution would be in accordance with the Iowa Administrative
Code, Section 133.4 (3) b.l, which says that the MCLs and
proposed MCLs are relevant and appropriate cleanup action levels
for contaminated ground water when HALs and NRLs are impractical
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- 43
to achieve.
The ground water downgradient of the site is used
for drinking water without treatment by residents living near the
site.
Although MCLs and the proposed MCLs would be applicable at
the tap for publicly operated water supply systems, these
action-levels are relevant and appropriate when the expected and
current use of the ground water is for drinking water.
In addition, the rules in Iowa for antidegradation of ground
water is relevant and appropriate for this remedial action.
The
- Iowa Administrative Code, section 61.2 (2) requires that the
quality of the ground water in the state shall not be degraded by
contamination.
This regulation is relevant and appropriate to
prevent further degradation of the ground water quality due to
migration of the plumes of ground water already contaminated from
the site.
At this time, no MCL, HAL or NRL have been established for
the PAHs detected in the ground water at the site.
Therefore, it
is appropriate to establish a site-specific alternative cleanup
action level for the PAH contaminants at this site.
At other
sites with similar ground water contamination, EPA has determined
that a cleanup action level of 10 ug/l (ppb), the-detection
limit, is relevant and appropriate for PAH contamination in
ground water.
The detection limit is the relevant and
appropriate action level for cleanup of the PAH contaminants in
the ground water at this site.
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44
Table 5-1 also lists the ambient water quality criteria
(AWQC) for the protection of human health and aquatic life as
chemical-specific ARARs for this ground water remedy.
These AWQC
are established pursuant to the Clean Water Act, 33 U.S.C.
~~1251, et. seq.
These criteria are to be considered in
implementing this remedy; however, because the promulqated and
proposed MCLs are more stringent, the AWQC are not relevant and
appropriate for cleanup of the ground water for this operable
. unit remedial action.
The AWQC are to be considered in the
implementation of this action because aquatic life and human
health may be affected from the discharge of contaminated ground'
water from this site to nearby Rock Creek, which flows to a lake
and then to the Mississippi River.
Fish from the river use the
creek and the lake for habitat.
The creek discharges to the
river just above the Upper Mississippi River Wildlife Refuge.
Commercial fishing is allowed in the river just downstream of
these areas.
There is a threat of ground water contamination
migrating from this site to the surface waters.
The PRPs
submitted to EPA a study of Rock Creek, which indicates no
contamination in the creek; however, the study included only one
sample of the tributary to the creek, which is adjacent to the
site.
Analysis of a sample from this tributary contained
detectable levels of chlorinated hydrocarbons; therefore, it will
be further investigated in the future RIfFS activities at the
site.
The AWQC are to be considered in implementing the cleanup
-------
45
of the ground water at this site for the protection of the
surface waters at the site.
Although it is possible that this operable unit remedy will
become the final remedy for ground water remediation of the
landfill and DAC areas, it is also possible that future RODs for
this site may modify or effect this remedy.
.
Information to be
gathered from future remedial investigations at this site will
include an assessment of the need for further ground water
remediation.
For example, future remedial investigations may
disclose new contaminants or may reveal that a greater volume of
ground water is contaminated than currently estimated.
In the
event that new information affects this selected remedy, then
future records of decisions may modify this operable unit
remedial action.
For example, the length of time to pump and
treat the ground water may be expanded or additional treatment
may be necessary.
In addition, future remedial action at the
site may include source removal in the landfill and DAC areas,
and such remediation may decrease the overall time necessary to
pump and treat the contaminated ground water.
Nevertheless, the
treatment of the extracted ground water in the landfill and DAC
areas will continue until ground water contaminated with PAHs,
BTEX and chlorinated hydrocarbons is remediated to the levels
identified herein as the chemical-specific ARARs.
Therefore, it
is appropriate to identify the contaminant-specific ARARs at this
time.
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. 46
Location-Specific ARARs
The location-specific ARARs for this ~erable unit remedial
action are identified in Table 5-2.
These requirements are based
on the location of the site and the effects the site may have on
its surrounding environment.
Because the site is near the
Mississippi River and the Upper Mississippi River Wildlife Refuge
(where bald eagles have been located), the standards found in
Table 5-2 for the protection of a wildlife refuge, endangered
species habitat and fish ahd wildlife are relevant and
appropriate requirements for this operable unit.
Because the
discharge of treated ground-water is directly into the
Mississippi River and the contaminated ground water discharges
directly to creeks adjacent to the site, which flow to the river,
these requirements are relevant and appropriate.
Action-Specific ARARs
The action-specific ARARs for this operable unit remedy are
identified in Table 5-3.
These ARARs are activity-based
requirements or limitations on actions taken with respect to the
hazardous substances found on the site.
This operable unit
remedy includes the treatment of ground water contaminated with
BTEX, PAHs and chlorinated hydrocarbons, which is regulated under
both the Clean Water ACT (CWA) and the RCRA.
The selected remedy includes the pretreatment of the
contaminated ground water using an air stripper and an overhead
activated carbon treatment unit.
The carbon filters may contain
-------
TABLE 5-2
LOCATION-SPECIFIC ARARs
Location Requirement Citation
Critical habitat upon Action to conserve Endangered Species Act
which endangered species endangered species or of 1973 (16 U.S.C. Sections 1531
or threatened species threatened species, et. seq.); 50 CFR Part 200.
depends Including consultation 50 CFR Part 402; Fish and
with the Department of Wildlife Coordination
the Interior Act (16 U.S.C. Sections 661 et. seq.)
33 CFR Parts 320 - 330 . .
Wildlife refuge Only actions allowed 16 U.S.C. Sections 668 et. seq.;
under the provisions of 50 CFR Part 27
16 U.S.C. Section 668
may be undertaken in
areas that are part of
the National Wildlife
Refuge System
Area affecting Action to protect fish Fish & Wildlife
stream or river or wildlife Coordination Act (16 U.S.C.
Sections 661 et. seq.); 40 CFR
6.302
TS2 T21RK719
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TABLE 5-3
ACTION-SPECIFIC ARARs
Action Requirements Citation
Discharge 01 Treatment Best Available Technology:
System Effluent
Use 01 best available technology (BA l) economically achievable Is CWA
required to control toxic and nonconventlonal pollutants. Use 01 40 CFR Section 122.44(a)
best conventional pollutant control technology (BCl) Is required to
control conventional pollutanls. Technology based limitations may be
determined on a case by case basis.
Water Quality Standards:
Applicable Federally approved State water quality standards must be 40 CFR Section 122.44
complied with. These standards may be In addition to or more and State regulations
stringent than other Federal standards under the CWA. approv~ under 40
CFR Section 131
Discharge limitations must be established at more stringent levels 40 CFR Section 122.44(e)
than technology based standards lor toxic pollulanls.
Best Management Practices:
Develop and Implement a Best Managemenl Pracllces program to prevent 40 CFR Secllon 125.1~
the release 01 toxic conslluents to surlace waters.
The Best Management Practices program must: 40 CFR Section 125.104
o Establish specific procedures lor the conlrol 01 toxic and
hazardous pollutant spills. .'
o Include a prediction 01 direction, rale 01 flow, and total
quantity 01 toxic pollutants where experience Indicates a
reasonable polentlal 01 equipment lallure.
0 Assure proper management 01 solid and hazardous waste In
accordance with regulations promulgated under RCRA.
-------
Acllon Requirements Citation
Discharge 01 Treatment Monitoring Requirements:
System Ellluent (continued)
Discharge must be monitored to assure compliance. Discharge will 40 CFR S~tlon 122.41(1)
monitor:
0 The mass 01 each pollutant
0 The volume 01 effluent
0 Frequency 01 discharge and other measurements as appropriate
Approved test methods 'Of waste constituent to be monitored must be 40 CFR Section 136.1-136.4
lollowed. Detailed requirements lor analytical procedures and
quality controls are provided.
Sample preservallon procedures. container materials, and maximum
allowable holding times are prescribed.
Comply with additional substantive conditions such as: 40 CFR Section 122.41(1)
o Duty to mitigate any adverse ellects 01 any discharge; and
0 Proper operation and maintenance 01 treatment systems.
Treatment, Storage, and Subtitle C and D of RCRA. guidelines and requirements for the Sections 3001 et. seq.
Disposal 01 Solid Wastes treatment, storage, and disposal 01 solid wastes. 01 RCRA, 42 U.S.C.
Irom Wastewater Sections 6901 et. seq.
Treatment Plant
TABLE 5-3 (continued)
Other Actlon-Speclnc ARAR. are II lied below.
Federal: 20 CFR Secllon. U104. 1810, and 192e, OSHA WOfklr Prdlctlon Standard.: Health and 88lely requITemlnl.IOf wOfkerllnYQIved In remedlalactlon..
Stlte: Iowa Code Anndated (I.C.A.» Section. 4558.171 II. I8q., Waler Quality; I.C.A. Section. 4558.211 It. eeq., Waler Treatment;
I.C.A. Sectlonl 4558.301 e.. eeq.. Solid Waste Oi.posal;
I.C.A. Section. 455E.1 et. eeq., Groundwater Protection; I.C.A. Section 4558.131 et. I8q., Air Quality;
Iowa Admlnlll..tlve Code, Chapter 60. Iowa Water Pollulion Control Regulation.: Analgou8to lederal discharge regulallons;
Iowa Admlnlllrativl Code, Chapter 38, and I.C.A. Section 4558.187. Waler well construction regulalions: Water well con8lrucllon must be regl8le/ed and pe/mlned.
l~J.PII!"'111
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47
hazardous wastes and will be disposed in accordance with
Subtitle C requirements of RCRA.
The source of these hazardous
-
wastes is the contaminated ground water, which seems to be
contaminated from the disposal of chlorinated hydrocarbons, such
as TCE and PCE, in the landfil~.
Although the disposal of
chlorinated hydrocarbons in the landfill has not been' confirmed,
these hazardous substances were found in the contaminated ground
water emanating from the landfill and chlorinated solvents were
used at the facility.
The chlorinated hydrocarbons found at the
site contain hazardous constituents and are sUfficiently similar
to hazardous wastes that the RCRA requirements will be relevant
and appropriate for disposal of the filters from the pretreatment
of the contaminated ground water.
After pretreatment the contaminants remaining in the ground
water will be treated in the existing onsite wastewater treatment
plant, which has an NPDES permitted discharge to the Mississippi
River.
Because this discharge is offsite, the NPDES permit
requirements are legally applicable requirements for this remedy.
Table 5-3 identifies the NPDES requirements established under the
CWA and the Iowa Water Quality laws and regulations.
The
existing NPDES permit limitations are to be considered in the
implementation of this remedy.
In the event that the existing
permit is modified upon review by IDNR or EPA, such modified
permit would be a legally applicable requirement for this
remedial action.
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48
The selected remedy will include construction and other
activities such that workers will be onsit~ implementing the
remedy.
OSHA Worker Protection Standards are applicable
requirements for this' action.
OSHA standards are also applicable
to protect workers from air emissions from the ground water
treatment and pretreatment units because workers will' operate and
maintain these units.
The state of Iowa regulates the construction of private
. water wells, Iowa Admin. Code, Chapter, 38.
Such regulations are
an important institutional control and are legally applicable.
The State of Iowa will prevent construction of such wells on the'
site and in the vicinity of the ground water contamination until
the remediation of the ground water is complete.
5.3
COST-EFFECTIVENESS
The selected remedy is cost-effective.
See Table 5-4 for
estimated cost of the selected remedy.
It provides overall
effectiveness proportional to its costs such that the remedy
represents a reasonable benefit for the cost expenditures.
The
selected remedy will provide a reduction in the contaminants of
concern in the ground water.
The selected remedy is less
expensive than the other alternatives evaluated, except for the
no action alternative.
utilization of the existing wastewater
treatment plant as part of the selected remedy provides a
-------
Alternative 2
~/D224fTh5-1
TABLE 5-4
SUMMARy OF COSTS FOR ALTERNATIVE 2
Extraction and Treatment using -
an Air stripper followed by Existing
Wasiewater Treatment Facility
1.
Non-Construction Costs
Engineering/ Construction
Design and Supervision
Contingencies
Permittin2:
Subtotal 1
2.
Component Installation Costs
Extraction System
Air stripper
Carbon (GAC) Unit for Air (2 units)
Heater /Blower /Dehumidifier
Building/Slab
Tanks
Pumos
Subtotal 2
3.
Non-Component Costs
Electrical /Instrumentation
Site Preparation
Subtotal 3
Total Capital Cost
56,000
56,000
15.000
$U7,OOO
$267,000
20,000
20,000
10,000
30,000
10,000
10.000
$367,000
$ 43,000
15.000
$ 58,000
$552,000
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. 49
cost-effective alternative to the alternative of building a
completely new wastewater treatment plant.
5.4
UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT
(OR RESOURCE RECOVERY) TECHNOLOGIES TO THE MAXIMUM EXTENT
PRACTICABLE/PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
The selected remedy will permanently treat, destroy, and
dispose of contaminants found in the ground water by extraction
. and treatment of ground water.
The selected remedy is protective
of human health and the environment.
The air stripper with overhead treatment removes the
majority of volatile organic contaminants, which would be
stripped from the extracted ground water and adsorbed onto
activated carbon.
The spent carbon containing the contaminants
would then be disposed of or recycled offsite in accordance with
RCRA Subtitle C.
The remaining contaminants would then be
treated in the existing plant by volatilization, adsorption, and
biodegradation.
The majority of contaminants remaining following
pretreatment would be semi-volatile organics.
The majority of
these compounds would be ~estroyed by biodegradation in the
existing wastewater treatment plant. The pretreatment unit in
conjunction with the existing treatment plant would achieve
compliance with current NPDES permitted effluent limitations.
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5.5
SIGNIFICANT CHANGES
Two significant changes which have been incorporated into
this ROD that were not d~scussed in the Proposed Pl.an and RIfFS
reports.
These changes have to do with ARARs that affect the
performance of this remedial action.
The first change is in regard to the new administrative
regulations established by the state of Iowa that became
effective on August 16, 1989.
According to the Iowa Admin. Code,
. Chapter 133, the hierachy 9f ground water cleanup action levels
have been established as the Health Advisory Level, the
Negligible Risk Level, and the MCL.
The rule was not effective
at the time the Proposed Plan and RI/FS were available for public
comment.
EPA considers the IDNR action levels to be applicable
requirements for ground water cleanup and listed these levels on
Table 5-1, Chemical-Specific ARARs, herein.
Second, in regard to the PAR contaminants, EPA believes that
the detection limit of 10 ug/l is an acceptable action level for
the PAR compounds found at this site.
EPA has used 10 ug/l as a
ground
1ter cleanup value at other superfund sites.
This is
also discussed in section 5.2, Attainment of ARARs, herein.
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51
RESPONSIVENESS SUMMARY FOR THE RECORD OF DECISION
1.1
OVERVIEW
The Proposed Plan, RI/FS Reports and Administrative Record
were available for public comment from July 24 through August 23,
1989.
A public meeting was also held on August 14 in the
Clinton, Iowa City Hall.
Comments received from the local
community, both in writing and during the public meeting, were
directed toward issues involving the effect of the site on human
health and the environment in general and not on the remedial
alternatives presented in the Proposed Plan.
The transcript from
the public meeting is available with the administrative record.
The local community, therefore, did not express a preference nor
indicate any adversity to EPA's preferred Alternative 2.
The
potentially responsible parties (PRPs), however, indicated that
they would prefer that the selection of either Alternative 2 or 3
be postponed until the design phase.
1.2
BACKGROUND ON COMMUNITY INVOLVEMENT
As part'of the community relations process, which included
interviews of the local community and preparation of a community
Relations Plan, several major community concerns were identified.
The Chemplex site is located in a rural area, approximately
5 miles west of the cities of Clinton and Camanche, Iowa.
In
addition, another NPL site, the DuPont/Todtz Landfill Site, is
located approximately one mile from Chemplex.
Therefore,
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52
citizens who live in the surrounding area have expressed concern
that the proximity of the sites to their property has caused
their property values to decline.
The local community also expressed concern regarding adverse
impacts that the two sites, as well as other industries in the
community, might have on their drinking water wells and air
quality.
Some of the members of the local community had concerns
regarding the concentrations of contaminants in their drinking
. water wells and the potential adverse health effects from
drinking ground water that had concentrations exceeding federal
standards.
Response:
During the pUblic meeting, several of these
concerns were raised and EPA responded to them.
Regarding the potential decline of property values and the
effect of contamination on an individual's property, the
individual may pursue a private action against the company
causing this contamination.
This is discussed on page 46 of the
Public Meeting transcript.
Regarding the citizens' concerns of the nature and extent of
contamination, EPA made the following points during the meeting:
The operable unit remedy is the first step in dealing with
the problem that exists at the Chemplex site.
This will
accomplish extraction and treatment of the contaminated ground
water plumes in the landfill and DAC areas to control the plumes
of contamination.
Further remedial actions will be undertaken to
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. 53
deal with the landfill and DAC areas soils and wastes as well as
further ground water extraction and treatment.
The Resource Conservation and Recovery Act (RCRA) was
enacted to control the generation, transport and management of
hazardous wastes.
As a result,'there has been a minimization of
the amount of waste that is being generated at this site.
is discussed on page 48 of the Public Meeting transcript.
This
Regarding the ground water contamination in the landfill and
DAC areas, the concentrations of contaminants, such as benzene
and trichloroethylene, exceed human health and environmental
standards and criteria (such as MCLs) in the ground water plumes.
of contamination.
initially defined.
The plumes of contamination have been
Also, analytical results from samples
collected from drinking water wells at the closest residences in
the downgradient plume direction indicate that these residential
wells are not contaminated.
Therefore, no individuals are
presently drinking contaminated ground water from these plumes.
One of the local citizens expressed a concern that TCE has
been detected in her drinking water well at 5 ppb, which is the
MCL value.
At the meeting, Dan Harper of ATSDR discussed the
significance of ingesting ground water at this concentration and
the basis of the MCL value.
Mr. Harper stated that ingesting
water at this level is expected to cause an additional one in
100,000 cancer risk during a lifetime exposure (70 years) to TCE
at a concentration of 5 ppb.
The effect of the additional
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54
increase of cancer risk should, therefore, not be a problem over
a period of several weeks or several years.
This response is
discussed further on page 29 of th~ Public Meeting transcript.
1.3
SUMMARY OF PUBLIC COMMENT~ AND LEAD AGENCY RESPONSES
The following comments were received on the Proposed Plan
and RI/FS Reports.
The first set of comments are from
potentially responsible parties for the site:
1.
Regarding number.and placement of extraction wells and
extraction capacity in the overburden and in the landfill area,
and bedrock aquifers in the DAC areas, the PRPs suggest that not
enough information is available to determine the number and
placement of extraction wells and extraction capacity in these
two areas.
Response:
The Proposed Plan acknowledged that the final
number, locations, and extraction capacity of the wells would be
determined during the design phase.
Additional information will
be developed during the remedial design to determine the number,
location and capacity of the extraction wells.
2.
The Focused Feasibility Study used inappropriate
treatment systems for a comparative analysis of alternatives.
Response:
See response to 13 below.
3.
There is no basis in the administrative record for
preselecting either a pretreatment unit in series with the
existing plant or a new treatment plant.
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55
Response:
The Focused FS clearly indicates that collection
of additional data during remedial design ~ay indicate that the
proposed alternative may be modified.
This provides flexibility
to utilize data obtained during the Remedial Design phase to
reevaluate the remedial action, if necessary.
The Phase II RI/FS prepared by the PRPs concluded that the
extracted ground water should be treated using the existing
wastewater treatment plant only.
It was determined by the Agency
that elevated levels of volatile organics (specifically
tetrachloroethylene and benzene) would cause increased plant air
emissions and potentially would cause exceedance of the existing'
NPDES permitted effluent levels.
Due to the fact that the
Phase II RI/FS failed to consider the effect of the elevated
levels of volatile organics and the effect of these compounds on
the performance of the existing plant, the Focused FS was
undertaken to evaluate treatment systems to take into account the
elevated levels of volatile organics in the ground water.
also important to emphasize that the treatment systems for
It is
pretreatment and a new plant were selected to provide a basis for
comparison of alternatives.
The Focused FS clearly indicates
that additional investigation work may provide additional
information which would warrant the modification of the selected
remedial alternative.
The PRPs also stated in their comments that "the means to
accomplish treatment cannot be determined at this time," however,
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56
the Phase II RI/FS makes the determination that it is appropriate
at this time to treat the extracted ground water by using the
existing plant only.
The Focused FS established a design basis in which to
evaluate all the alternatives based on available data.
It was
estimated based on the current understanding of the hydrogeologic
system' that the extraction and treatment of approximately 140 gpm
from the two areas would be required to meet the objective of the
. operable unit ground water remedy of controlling the plumes of
contamination.
It is important to emphasize that the
alternatives were evaluated using this established design basis'
and the Focused FS clearly indicates this.
The Phase II RI/FS
used a similar design basis to recommend treatment at the
existing plant only.
The PRPs state in their comments that "it
is premature to select pretreatment rather than the construction
of a new treatment facility," however, they did not similarly
consider it premature to recommend treatment at the existing
plant only as opposed to a new plant.
The Agency believes that sufficient information is available
in the administrative record to conclude that treatment at the
existing plant only will not be adequate treatment.
In addition,
the Agency believes that pretreatment is required if the existing
plant is to be used to treat extracted ground water.
If
significant information is discovered during remedial design that
indicates the existing plant will not have the capacity to handle
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57
the additional load, the selected remedy may be modified and EPA
may reevaluate the remedial action.
This was clearly indicated
in both the Proposed Plan and the Focused FS.
4.
The PRPs suggested that MCLs are not legally applicable
nor relevant and appropriate ARARs for this operable unit
remedial action.
The PRPs also state that this is an !' interim"
ground water remedy.
Response:
The MCLs promulgated under the federal Safe
-Drinking Water Act (SDWA) were established for protection of
human health.
The MCLs are legally applicable to regulate water
supply systems for 25 people or more.
In accordance with EPA
guidance, MCLs are relevant and appropriate cleanup requirements
for ground waters at sites that are a current and/or potential
source of drinking water.
At the Chemplex site, the aquifers are
current and potential sources of drinking water.
This operable unit ground water remedy is not an "interim"
remedy but it is the first stage of the remedial process for the
Chemplex site.
Additional remediation may include cleanup of the
soils and wastes on the Chemplex site as well as additional
ground water remediation.
The MCLs as goals are relevant and
appropriate.
5.
The PRPs commented that the Clean Air Act regulations
are not legally applicable or relevant and appropriate
requirements for ground water treatment.
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58
Response;
The EPA agrees that the Clean Air Act (CAA) is
not an ARAR for this site.
However, this remedy must meet the
nine criteria for selection of a remedy.
The most important of
the nine criteria is protection of human health and the
environment.
Therefore, air di~persion modeling and a risk
assessment will be conducted for any treatment unit that might
release hazardous substances into the air.
Concern with protection of human health and the environment
for the air pathway of exposure has prompted federal and state
agencies to propose air regulations.
Therefore, both federal and
state air regulations for wastewater treatment units may be
promulgated in the future.
6.
The Focused Feasibility study does not mention or
consider the institutional control on ground water use provided
by the Iowa Environmental Act.
Response:
The Iowa Environmental Act was included as an
ARAR in the Proposed Plan and is included as an ARAR in the ROD.
7.
Two of the potential ARARs listed in Table 2 of the
Focused Feasibility Study do not appear to be appropriate for
this site:
the Endangered Species Act and the Wildlife Refuge
System restrictions.
Response:
The location-specific ARARs for this operable
unit are identified in Table 5-2.
These requirements were
selected based on the location of the site and the effects the
site may have on its surrounding environment.
Because the site
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59
is near the Mississippi River and the Upper Mississippi River
wildlife Refuge (where bald eagles have be~n located), the
standards found in Table 5-2 for the protection of wildlife
refuge, endangered species habitat and fish and wildlife are
relevant and appropriate requirements for this operable unit.
These requirements may not be legally applicable because the
discharge of treated ground water is to the Mississippi River
(not directly to the Wildlife Refuge).
Nevertheless, these
requirements are relevant and appropriate.
8.
The PRPs commented that Table 4 of the Focused
Feasibility Study states that there is "no reduction in risk"
under the no action alternative.
However, as previously stated,
there is presently no known exposure via ingestion or ground
water contaminated from the site.
Response:
Both the RIfFS and EA Reports prepared by the
PRPs did not address the potential risk from ingestion of ground
water, which is a drinking water source.
The no action
alternative would not contain any provisions to control the
contaminant plumes.
Therefore, residents near the site in the
direction of ground water flow could some day be drinking ground
water as contaminated as the plumes if the no action alternative
is incorporated.
Even if institutional controls are implemented
with the no action alternative, this would not be responsive
because the plumes could still migrate to the residential wells.
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60
The statement that... "there is no reduction in risk under the no
action alternative" is correct.
9.
The PRPs commented that an NPDES permit wo~ld not
necessarily be required for the discharge of treated ground water
because the discharge is near the site.
On pages 4, 10, and throughout the document, the -.Focused
Feasibility study states that an NPDES permit would be required
for a new treatment plant built at the site.
According to
section 121(e) of CERCLA, "No Federal, State or local permit
shall be required for the portion of any removal or remedial
action conducted entirely onsite..." the preamble to Subpart E of
the proposed NCP (53 FR 51394) says that EPA's interpretation of
"onsite" further includes situations where the remedial activity
occurs entirely onsite but the effects of such activity cannot be
strictly limited to the site.
For example, a direct discharge of
CERCLA wastewater would be an onsite activity if the receiving
water body is in the area of contamination or is in very close
proximity to the site, even if the water flows offsite.
An
actual NPDES permit may not be required: rather, only the
substantive requirements of the discharge permit may have to be
met.
Response:
It should be noted that Tables E1 and E6 of the
Executive Summary of the PRP's Phase II Remedial Investigation:
Volume II, state that the "Clean Water Act:
discharge of treated
ground water to surface water must meet NPDES limits".
The
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61
discharge is presently regulated under the NPDES program and it
is an offsite discharge.
The exception to this rule, set forth
in section 121(e) of CERCLA, 42 U.S.C. S9621(e), applies only to
onsite discharges.
Finally, the interpretation of "onsite"
action recited in the comment is from the proposed NCP, which has
not been promulgated.
10'.
The Focused Feasibility study drew conclusions
regarding pretreatment limits and the effectiveness of treatment
, from extremely limited data on the nature of process wastewater.
Response:
We recognize that the concentrations of 1000 ppb
for benzene and 10,000 ppb naphthalene are based on a one time
event and may not reflect fluctuations in the composition of
industrial wastewater.
This is the best information available at
this time in regard to calculation of estimated effluent
concentrations.
In addition, it is important to note that
Quantum does have a plant wide commitment to keep the benzene
concentrations in the influent wastewater to no greater than
1000 ppb.
The use of the 1000 ppb should provide a conservative
estimate of the benzene concentrations in the influent.
In
conclusion, the calculations regarding pretreatment limits are
accurate and are based on the best available information.
11.
The PRPs commented that the Focused Feasibility study
discussed several design points which can be addressed more
appropriately and completely during remedial design including
effluent limits for pretreatment.
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62
Response:
A pretreatment system should be able to remove
99% of the volatile organic compounds which would likely be below
the concentrations in the process wastewater from Quantum.
In
any event, neither the Proposed Plan or ROD specify that a
pretreatment unit must achieve ~oncentrations lower than the
influent to the wastewater treatment plant from Quantum.
The
effluent limits for pretreatment will be more fully addressed
during the design phase.
The following comments were received from the local citizens
during the public meeting.
1.
During the Public Meeting, one member of the local
community expressed concern regarding the length of time (five
years) from when the site was proposed for the NPL until the
start of cleanup, which is just to begin.
Response:
EPA explained during the Public Meeting that
there is a priority system established for responding to
Superfund Sites.
There is limited money and resources to be able
to respond to all of these sites at once.
Refer to page 38 of
the Public Meeting transcript for more explanation.
2.
One of the local citizens asked whether the drawdown
caused by the proposed extraction wells would influence the
amount of water available for the surrounding drinking water
wells.
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. 63
Response:
There will still be sufficient water available
for drinking water purposes.
For more dis~ussion, refer to page
40 of the Public Meeting transcript.
3.
One of the local citizens asked if the NPDES discharge
was ever monitored by EPA.
Response:
The water from the NPDES discharge is ~onitored
by the Iowa Department of Natural Resources (IDNR).
program has been delegated to IDNR by EPA.
The NPDES
4.
One of the local citizens had a question regarding the
water quality of the drinking water supply wells located at the
Quantum Chemical Company (formerly Chemplex) plant.
Response:
The EPA responded that the water supply wells are
much deeper than the contaminated ground water plumes, and,
therefore, did not anticipate that the water supply wells would
be contaminated.
Bob Schuler of Quantum also responded that the
water supply wells have been sampled and that the analysis
indicate that the water supply wells were not contaminated.
These responses are listed on page 53 and 54 of the Public
Meeting transcript.
It should be noted that this ground water
operable unit remedy should prevent migration to the deeper
aquifers.
5.
One of the local citizens asked if the fractures in the
bedrock could cause the monitoring to be ineffective in detecting
some of the contamination.
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64
Response:
The monitoring wells are screened to cover a
large area as opposed to one particular element of the ground
water.
Also, the fractured bedrock hydrogeology is. taken into
account for placement: of monitoring wells and extraction wells.
Therefore, the EPA is satisfied. that the extraction wells will be
placed to prevent contamination from migrating further.
also discussed on pages 56 and 57 of the Public Meeting
This is
transcript.
6.
One of the local citizens asked when the Remedial Action
(placement of extraction wells) would begin.
Response:
The EPA anticipates that additional monitoring
wells to delineate the extent of contamination can begin in fall
1989 and that the extraction and treatment process will start
during the next construction season.
Refer also to page 65 and
66 of the Public Meeting transcript.
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c: il\
Sf;: .u
~
~
TERRY E. BRANSTAO. GOV£ANOfI
DEPARTMENT OF NATURAL RESOURCES
LARRY .J. WILSON, OIH£C'TOH
August 3, 1989
{Nancy,: J.:-Johnson,....P..E.,~
US EPA,'Region VII.
Superfund Branch
726 Mi~nesota Avenue
Kansas City, KS 66101
RgCf.\\[ED.
~y~ 1 () '98~,
~oit ~
Hazardous"
Information
US EPA Reg}
Philadelph:~
[
~
Dear Nancy:
We have reviewed the proposed plan for the Chemplex Superfund
site near Clinton, Iowa. The department is familiar with this
site and has previously participated with you in discussions,
about remedies at the site. The proposed plan is recognized to be
the first step. in the remedial effort at this site. The implemen-
tation of this first step should be effective in controlling the
release of groundwater contaminants from the site. We agree that
these interim measures should be implemented while additional
studies are performed to complete the necessary remedial work at
the site. It is noted that the existing waste water treatment
plant will be used to treat groundwater contaminants. It will be
necessary for the company to provide notice to the DNR Wastewater
Permits Section of the impacts and additional discharges, if any,
that will result from treating the contaminated groundwater. Upon
receipt of this notice the department can determine if there will
be a need for an amendment to the NPDES permit. If the treatment
process releases significant volatile air contaminants, the Air
Quality section will also need to review emissions to determine
if air emission controls are necessary. We believe that these de-
tails can be resolved during remedial design and will not impede
the implementation of the:s'~lected. alternative.
, .
,
We believe that the recommended
itial action to respond to this
tion while the final remedy is
this opportunity to comment. If
contact me at 515/281-4968.
alternative is an appropriate in-
site and support its implementa-
being developed. We thank you for
you have any questions, please
./i4:' /~
R£C£lVED
AUG - 9 1989
eROGRAM INTEGRATION
!RAACij
WALLACE STATE O~~ICE BUILDING I DES MOINES. IOWA 50319/ St~281.S,.sl TDD 515-242-5967 I fAX 515-281.8895
Morris L. Preston, P.E.
Supervisor
SOLID WASTE SECTION
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