PB98-964309
EPA 541-R98-173
March 1999
EPA Superfund
Record of Decision:
Pester Refinery Co.
El Dorado, KS
9/29/1998
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RECORD OF DECISION
PESTER REFINERY CO./PESTER BURN POND SITE
GROUND WATER OPERABLE UNIT
El Dorado, Kansas
DECISION SUMMARY
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RECORD OF DECISION
PESTER REFINERY CO./PESTER BURiN POND SITE
GROUND WATER OPERABLE UNIT
EL DORADO, KANSAS
DECLARATION
Statement of Basis and Purpose
This decision document presents the selected remedial action for the Ground Water Operable Unit
(OU2) of the Pester Refinery Co. Site (commonly referred to as the Pester Bum Pond Site). El
Dorado. Butler County. Kansas. The selected remedy was chosen in accordance with the
Comprehensive Environmental Response. Compensation and Liability Act (CERCLA). as amended
by the Superfund Amendments and Reauthorization Act (SARA) and the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP). This decision document is based on the
information contained in the administrative record for this Site. The State of Kansas concurs with
the selected remedy.
Assessment of the Site
Based on the conclusions of the OU2 Risk Assessment (RA) and the OU2 Remedial Investigation
and Feasibility Study (RI/FS), the identification of response objectives, and the identification and
evaluation of potential response actions, the U. S. Environmental Protection Agency (EPA) and the
Kansas Department of Health and Environment (KDHE) have determined that no additional action
other than ground water monitoring is necessary for the Ground Water Operable Unit of the Pester
Refinery Co. Site to protect human health and the environment.
Description of the Selected Remedy
The EPA and KDHE have selected "No Action" as the remedy for the Ground Water Operable Unit
of the Pester Refinery Co./Pester Bum Pond Site. The selected "No Action"' remedy for OU2
involves no additional measures to eliminate, reduce, or control threats to human health and the
environment other than mitigative measures implemented as components of the Soil and Sludge
Operable Unit (OU1) Record of Decision. Those measures include institutional controls in the form
of a deed restriction controlling development of the property and a fence to restrict site access, the
treatment and/or removal of the source material (oily sludge in the ponds on site), and the operation
of the underground interceptor trench. The underground interceptor trench was constructed to
prevent separate-phase hydrocarbon and dissolved-phase seeps from the ponds at the Site from
reaching the river. KDHE and EPA anticipate that the process of extracting, treating, and returning
the seep water to the ponds for recirculation will also reduce the concentrations of contaminants in
ground water through oil-water separation, physical filtration, biodegradation. and other natural
processes that will act to reduce contaminant concentrations.
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Actions associated with the selected "No Action" remedial alternative will consist of ground water
monitoring and sediment sampling. Ground water monitoring of the alluvial, upper bedrock, and
lower bedrock aquifers will be conducted to verify that the concentrations of contaminants in the
alluvial aquifer and the underlying, less-contaminated upper bedrock aquifer continue to decline and
that the concentrations of the chemicals of concern in the underlying deep bedrock aquifer do not
increase. Sediment sampling in the West Branch Walnut River will be conducted to augment the
limited information on potential impacts historical releases from the Site may have had on the river.
Ground water monitoring and sediment sampling will be conducted on a quarterly basis to provide
a clearer assessment of baseline conditions, account for seasonal variations in ground water level
and contaminant concentrations, and permit an assessment of the effectiveness of the OU1 remedy
in restoring the ground water conditions at the Site and protecting the West Branch Walnut River.
After two years, the frequency of monitoring and sediment sampling will be re-evaluated by KDHE
and EPA.
Statutory Determinations
As required by CERCLA for sites where any hazardous substances, pollutants, or contaminants
remain on site, reviews of the remedy must be conducted by KDHE and EPA at least every five
years to verify that human health and the environment are being protected by the remedy. For sites
with multiple operable units, one five-year review would be conducted for the combined operable
units. The first five-year review for OU1 and OU2 of the Site will be conducted no later than five
years from the initiation of the remedial action for OU1, and an additional five-year review will be
conducted at least every five years thereafter. The five-year reviews will continue as long as
hazardous substances remain on site in the alluvial and upper bedrock aquifers.
The EPA and KDHE have determined that no further action is necessary to protect human health
and the environment from exposure to the ground water at the Site. In addition, the fact that the
alluvial aquifer is not a usable drinking water source, the expectation that contamination levels at
the Site will continue to decline as a result of the OU1 remediation activities, and the belief that the
operation of the seepage interceptor trench as a component of the OU1 remedy is effectively
preventing the off-site migration of contaminated ground water, and that institutional controls will
prevent any future residential use or well drilling at the Site contribute to KDHE's and EPA's
determination that no additional measures are necessary at the Site at this time.
Based on the conclusions of the OU2 RA and the OU2 Rl/FS, the identification of response
objectives, and the identification and evaluation of potential response actions. KDHE and EPA have
determined that no additional action other than ground water monitoring and sediment sampling is
necessary for the Ground Water Operable Unit of the Pester Refinery Co. Site to protect human
health and the environment.
Re^onal Administrator Dat/ f
A Region VII / '
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RECORD OF DECISION
PESTER REFINERY CO./PESTER BURN POND SITE
GROUND WATER OPERABLE UNIT
El Dorado. Kansas
DECISION SUMMARY
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DECISION SUMMARY
TABLE OF CONTENTS
TABLE OF CONTENTS i
1.0 SITE NAME. LOCATION. AND PHYSICAL SETTING ... 1
1.1 Site Name ........ 1
1.2 Site Location ........ I
1.3 Physical Setting. ....... 1
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES. ... 2
3.0 HIGHLIGHTS OF COMMUNITY INVOLVEMENT ... 4
4.0 SCOPE AND ROLE OF THE GROUND WATER OPERABLE UNIT . 4
5.0 SITE CHARACTERISTICS AND INVESTIGATIVE FINDINGS . 5
5.1 Original Site Characterization. ..... 5
5.2 OU1 Remedial Investigation ...... 6
5.3 OU1 Feasibility Study. ...... 7
5.4 OU2 Focused/Abbreviated Remedial Investigation ... 8
6.0 SUMMARY OF SITE RISKS 11
6.1 The Risk Assessment . . . . . . - 11
6.2 Contaminant Transport . . . . . . 13
6.3 Ecological Risks . . . . . . . 15
6.4 Remediation Goals . . . . . . . 15
7.0 DESCRIPTION OF THE SELECTED "NO ACTION" REMEDY . . 18
8.0 SIGNIFICANT CHANGES FROM THE PROPOSED PLAN. . . 19
GLOSSARY
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Figure 1 - Site Location Map
Figure 2 - Site and Vicinity Map
Figure 3 - Geologic Cross Section
Figure 4 - Site Features Map
Figure 5 - Alluvial Aquifer Potentiometric Surface Map. 6/17/94
Figure 6 - Conceptual Cross-Section of Ground Water Contamination Distribution
Table 1 - Summary of Compounds Detected in Ground Water
Maximum Concentrations - June 1994 Sampling Event
Table 2 - Chemicals of Potential Concern
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1.0 SITE NAME. LOCATION, AND PHYSICAL SETTING
1.1 SITE NAME
Although the Site is called the "Pester Refinery Co." Site on the EPA Comprehensive
Environmental Response. Compensation and Liability Information System ICERCLIS) data
system, the National Priorities List (NPL) Site as originally described in site ranking
documents focused somewhat more narrowly on a croup of waste (bum) ponds owned by
the bankrupt Pester Refining Co.. and not the refinery as a whole, which is operated by
Coastal Refining and Marketing Co. Accordingly, this OU2 Record of Decision addresses
these ponds and their environs rather than the entire refinery. The site has CERCL1S ID No.
KSD000829846. This is a state of Kansas-lead site with PRP cleanup ongoing as Operable
Unit 1 of the Site.
1.2 SITE LOCATION
The Site is located on a 10-acre tract located in El Dorado. Kansas, approximately 30 miles
northeast of Wichita. Kansas (see Figure 1). The Site is located in the southwest quarter of
Section 26. Township 25 South. Range 5 East. Butler County, Kansas.
Industrial and agricultural lands surround the Site (see Figure 2). Wastewater treatment and
aeration ponds owned and operated by Coastal Refining and Marketing, Inc. (Coastal) are
located south of the Site. West of the Site is an active refinery owned and operated by
Coastal and a Santa Fe Railroad spur that services the refinery. The West Branch Walnut
River flows along the north and east edge of the area to be remediated. Agricultural land
lies east of the Site across the river. As noted above, the refinery and wastewater treatment
and aeration ponds owned by Coastal are outside the focus of this remedy, which addressed
the former Pester bum pond and connected ponds and their environs.
1.3 PHYSICAL SETTING
The Site lies within the Osage Plains section (Flint Hills Upland subsection) of the Central
Lowland Physiographic province. In general, the topography is characterized by flat-topped.
steep-sided hills capped by chert-bearing limestone. The Site is underlain by terrace and
alluvial sediments of Pleistocene-Recent age deposited by the West Branch Walnut River
and Permian age units of the Barneston Limestone Formation. There are three aquifers
beneath the Site: 1) an alluvial aquifer ranging in thickness from 2 to 17 feet and consisting
of clayey silts and fine sands with local gravel beds: 2) an upper limestone bedrock aquifer
(Fort Riley Limestone Member of the Barneston Limestone) consisting of thin to massively
bedded fossiliferous limestone and clayey shale; and 3) a lower limestone bedrock aquifer
(Florence Limestone Member of the Barneston Limestone) consisting of fossiliferous
limestone with interbedded chert. There is a confining calcareous shale (Oketo Shale
Member) separating the upper and lower bedrock aquifers (see Figure 3).
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Ground water in the region is drawn primarily from the shallow bedrock aquifers (Fort Riley
and Florence limestones), with lesser amounts from the shallow alluvial aquifer because that
aquifer is iess commonly present. The bedrock aquifers are characterized by jointed and
fractured limestone that may be confined.
The direction of ground water flow in the alluvial aquifer at the Site is generally northeast
and east toward the river with the possibility of some radial flow to the south and southwest
of the bum pond. Data suggest that the alluvial aquifer and the Fort Riley Limestone aquifer
are hydraulically connected and are locally recharged by the ponds on the Site. Ground
water within the Fort Riley Limestone aquifer is interpreted to flow northeast and east from
the ponds with partial discharge into the West Branch Walnut River. Ground water in the
Florence Limestone aquifer is interpreted to flow eastward from the Site.
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
The refinery occupying the area immediately west of the Site was constructed in 1917. soon after
the discovery of oil at El Dorado in 1915. The refiner.- and surrounding area were purchased by
FINA in 1958. The bum pond was built by FINA around the time of the purchase. FINA disposed
of petroleum waste products generated by normal refinery operations by running a pipe from the
refinery to the burn pond. The pond was used to store various refinery byproducts such as slop oil
emulsion solids. API separator sludge, and heat exchanger bundle cleaning sludge. When the waste
products were of a very gaseous nature. FINA would ignite the waste product as it came out of the
pipe. Whatever did not bum was discharged out of the pipe into the pond.
The Site historically contained a bum pond, a stormwater pond, and a smaller settling pond (see
Figure 4). The dike separating the burn pond and the larger stormwater pond was breached.
resulting in a U-shaped pond. Eventually the dike between the stormwater pond and the settling
pond also was breached, creating common water between all three ponds. Except for the historical
references, all references to the "burn pond'* in this document refer to all three interconnected ponds
at the Site.
An open interceptor trench was installed in the late 1950s or early 1960s to intercept seepage from
the bum pond to the West Branch Walnut River. The trench was excavated to the top of weathered
bedrock and sloped to the east where fluids were collected and pumped back up to the ponds onsite.
Although typically effective, the trench occasionally overflowed or was inundated and carried
contaminants into the river.
On January 1. 1977. Pester purchased the refinery from FINA and continued refinery operations.
Pester filed for bankruptcy on February 25.1985. Subsequent to Pester's bankruptcy. Coastal Derby
Refining Company (now Coastal Refining and Marketing, Inc.) purchased the refinery with the
exception of the tract of land containing the bum pond. The tract occupied by the bum pond is still
owned bv Pester.
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On February 28. 1986. K.DHE Administrative Order =86-E-16 was issued requiring Pester to
conduct a site investigation of this surface impoundment, perform monitoring, and submit a Bum
Pond Closure Plan.
The Pester Refinery Co. Site was placed on the N P L on January 31. 1989. by the EPA pursuant
to its authority under CERCLA as amended by SARA. Following initial investigations, a Consent
Order was signed between Pester. FINA. and KDHE (April 19. 1990) to conduct the remedial
investigation/feasibility study (RI/FS) activities at the Site.
During late March 1992. a subsurface interceptor trench was constructed on the north and east sides
of the bum pond between the pond and the West Branch Walnut River to prevent the seepage of
contamination from the bum pond into the river in those areas. This trench extended east and south
of the existing open interceptor trench. The subsurface interceptor trench was dug into weathered
bedrock and sloped to a central collection point. Appreciable thicknesses of oil that accumulate at
the central collection point are periodically skimmed off of the water in the trench and disposed.
Water extracted from the subsurface trench system is discharged back to the bum pond.
A Record of Decision (ROD) was issued for the Site in September 1992. The ROD split the Site
into two operable units, a soil and sludge operable unit (OU1) and a ground water operable unit
(OU2), because ground water contamination at the Site had not been adequately characterized at that
time. The main remedial elements specified in the ROD for OU1 included: excavation of sludge
from the three interconnected ponds; separation of the sludge into Recovered Refinery Feedstock
(RRF oil), water, and residual solids; treatment, transportation, and off-site disposal of the residual
solids; transportation of the RRF oil for incorporation into the refining process; and bioremediation
of the contaminated soils in the ponds.
The KDHE. FINA. and Pester entered into a Consent Order to complete a Remedial
Design/Remedial Action (RD/RA) for OU1 of the Site in September 1993. The treatability study
for the soil was completed in the fall of 1994. The pond sludge dredging and removal and recycling
of oil contained in the sludge began in December 1995 and continued through March 1996. The
bioremediation design document for the soil portion of OU1 establishes the organization and
technical basis for the bioremediation of the pond soils. Bioremediation of the pond soils is being
conducted in a phased approach: Phase I has been completed and focused on remediating half of
the stormwater pond while simultaneously gathering bioremediation performance data; Phase II is
underway and is focused on addressing the remainder of the stained soil in the ponds.
In December 1993, FINA and KDHE entered into a Consent Order to conduct RI/FS activities for
OU2.
In August 1996. FINA requested that KDHE permit the construction of an extension of the
northwestern end of the subsurface interceptor trench at the Site to replace the existing open
interceptor trench. The open trench is subject to flooding by the West Branch Walnut River and has
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overtlowed on several occasions, releasing wastes into the river. K.DHE approved the interim
measure and the trench extension has been completed.
3.0 HIGHLIGHTS OF COMMUNITY INVOLVEMENT
A draft Community Relations Plan was prepared to the Site in June 1990 by the responsible parties
and was implemented by KDHE. A public meeting was held after community interviews in October
1990. prior to the Start of the GUI RI/FS activities. The OU1 RJ and FS reports were released to
the public in 1991 and 1992. respectively. On August 27. 1992. a public meeting was held in El
Dorado. Kansas, to present the Proposed Plan tor OU1. Notice for the public meeting was published
in the El Dorado Times.
On September 2. 1998. a public meeting was held at the Bradford Memorial Library in El Dorado.
Kansas, to present the Proposed Plan for OLJ2 and a concurrently offered Explanation of Significant
Differences for OU1. Notice for a 30-day public comment period and the public meeting was
published in the El Dorado Times and was provided to a number of local and regional public and
private entities that might have interest in the Site. Information repositories containing the
Administrative Record for the Site are available at the Bradford Memorial Library in El Dorado.
at the KDHE office at Forbes Field in Topeka. and at the EPA Region VII office in Kansas City.
Kansas.
4.0 SCOPE AND ROLE OF THE GROUND WATER OPERABLE UNIT
The September 1992 ROD for the Site split the Site into two operable units, a soil and sludge
operable unit (OU 1) and a ground water operable unit (OU2), because ground water contamination
at the Site had not been adequately characterized at that time. Certain aspects of the OU1 remedy
have contributed to the mitigation of ground water contamination and have diminished the potential
risk posed by that contamination. Exposure controls implemented as elements of the OU1 remedy
include institutional controls in the form of a deed restriction controlling development of the
property and a fence to restrict site access, the removal of the material that served as the original
source of ground water contamination (oily sludge in the ponds), and the operation of the
underground interceptor trench.
With the dredging of the oily sludge from the ponds, the source for ground water contamination has
likely been removed. The levels of contamination can reasonably be expected to remain constant
or decline following the removal of the source. With the presence of an active bioremediation
system in the ponds and the recirculation of biologically active ground water through the pond.
alluvial aquifer, interceptor trench, and treatment train, it is anticipated that treatment and
biodegradation and other natural attenuation processes will continue to reduce the concentration of
chemicals of concern in alluvial ground water (Table 2).
The shallow alluvial aquifer is the most significantly impacted water-bearing zone at the Site, but
is not employed as a drinking water source in the area and does not yield sufficient water to serve
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as a domestic water supply. Aquifer testing conducted as part of the OU2 R.I indicated a hydraulic
conductivity for the combined alluvial and upper bedrock aquifers of 3.7 X IO"1 cm/s. Given the
maximum saturated thickness of approximately 20 feet for the combined saturated zones of these
aquifers that are in communication with each other, the projected maximum sustained yield of the
aquifers would be insufficient to serve as a permitted domestic water supply in Kansas. In addition.
the total dissolved solids content of water from the thin veneer of saturated alluvium at the
upgradient edge of the Site exceeds the Secondary Maximum Contaminant Limn for that parameter.
suggesting that the water would be non-potable as a result of taste, odor, color, or other non-
aesthetic effects. The underlying upper bedrock aquifer, while significantly less impacted, contains
elevated concentrations of volatile organic compounds (VOCs), arsenic, and barium. Both the
alluvial aquifer and the upper bedrock aquifer normally discharge to the West Branch Walnut River
but are currently being captured by the underground interceptor trench. No chemicals of concern
for the Site have been detected at significant concentrations in the lower bedrock aquifer, a potential
drinking water aquifer. The presence of the shale zone within the upper bedrock aquifer appears
to act as an aquitard. isolating the lower bedrock aquifer to some extent from the downward
migration of contaminants present in the overlying aquifers.
An open interceptor trench was installed in the late 1950s or early 1960s to intercept seepage from
the bum pond to the West Branch Walnut River. The trench was excavated to the top of weathered
bedrock and sloped to the east where fluids were collected and pumped back up to the ponds on site.
Although typically effective, the trench occasionally overflowed and carried contaminants into the
river. During late March 1992. the original subsurface interceptor trench was constructed on the
north and east sides of the bum pond between the pond and the West Branch Walnut River to
prevent the seepage of contamination from the burn pond into the river in those areas. This trench
extended east and south of the existing open interceptor trench. The subsurface interceptor trench
was dug into weathered bedrock and sloped to a central collection point. Appreciable thicknesses
of oil that accumulate at the central collection point are periodically skimmed off of the water in the
trench and disposed. Water extracted from the subsurface trench system at the collection point is
treated by oil-water separation and mechanical filtration and is discharged back to the burn pond.
In August 1996 Fina requested that KDHE permit the construction of an extension of the
northwestern end of the subsurface interceptor trench at the Site to replace the existing open
interceptor trench. KDHE approved the interim measure and the trench extension has been
completed. KDHE and EPA anticipate that the process of extracting, treating, and returning the
seep water to the ponds for recirculation will also reduce the concentrations of contaminants in
ground water through oil-water separation, physical filtration, biodegradation. and other natural
attenuation processes.
5.0 SITE CHARACTERISTICS AND INVESTIGATIVE FINDINGS
5.1 ORIGINAL SITE CHARACTERIZATION
Pursuant to the 1986 KDHE Administrative Order, Pester retained Mid West Environmental
Consultants (MWEC) to investigate the Site and provide site characterization of the pond.
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ground water, and soil. The MWEC investigation covered the entire refinery. MWEC
identified constituents in the sludge, soil, ground water, and surface water. These
constituents included lead, chromium, phenols, and oil and grease in the sludge and the soil
under the pond. Separate-phase hydrocarbons and dissolved-phase benzene, toluene.
xylenes. ethylbenzene. and oil and grease were identified in the ground water, and dissolved-
phase phenols, benzene, toluene, ethylbenzene. and oil and grease were identified in the
pond water. KDHE has allowed the pond to be periodically de-watered and the effluent
treated at the Coastal wastewater treatment plant contingent upon meeting National Pollutant
Discharge Elimination System (NPDES) permit limits. Chromium and lead were not
detected in any surface water samples. Chloride and selenium were detected in a spring
adjacent to the river. Surface water sampling in the West Branch Walnut River indicated
the presence of oil and grease, phenols, sulfide. chloride, arsenic, barium, and selenium at
concentrations below the water quality standards for the protection of human health (i.e..
drinking water Maximum Contaminant Levels [MCLs] and lifetime Health Advisory
concentrations). Sediment sampling in the river indicated that concentrations of oil and
grease increased along the reach of the river adjacent to the Site and decreased immediately
downstream. Phenols and sulfide increased along the length of the Site in river sediments.
Concentrations of arsenic, lead, and selenium increased along the length of the Site and
decreased downstream. Concentrations of barium increased downstream. The results of the
site investigation were to be used by Sunbelt Environmental Management (Sunbelt) to
develop a closure plan for the bum pond. In 1989, Groundwater Technology, Inc. (GTI)
was retained by FTNA to summarize previous data collected by MWEC. Sunbelt, and
KDHE.
5.2 OU1 REMEDIAL INVESTIGATION
FINA retained Metcalf and Eddy (M & E) to perform the initial Rl/FS of the Site under the
April 19.1990, Consent Order between Fina. Pester, and KDHE. The RJ consisted of five
primary components: 1) review of existing data: 2) installation of five additional monitoring
wells to complement the seven existing monitoring wells: 3) verification of the volume and
chemical and physical nature of the sludge; 4) dye-tracer testing of the storm sewers; and
5) completion of the sludge, soil, ground water, and surface water sampling program.
Sludge samples were collected at three sampling locations within the burn pond to
characterize the chemical and physical nature of the sludge. These samples were analyzed
forVOCs and metals.
Contaminants identified in the sludge samples included xylenes. 2-methylnaphthalene.
benzo(a)anthracene, chrysene. phenanthrene, pyrene. arsenic, barium, chromium, and lead.
Soil samples were collected at four sampling locations beneath the sludge in the ponds.
Organic contaminants detected in the soil samples included ethylbenzene. toluene, xylenes.
2-methylnaphthalene. benzo(a)anthracene.chrysene,naphthalene.phenanthrene.phenol.and
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pyrene. Barium was the only metal detected in the Toxicity Characteristic Leachate
Procedure (TCLP) metals analyses of soil samples: it was detected at a non-hazardous
concentration.
Analytical results for samples collected from wells screened in the alluvial aquifer around
the Site indicated that contamination is present in the alluvial aquifer. Elevated
concentrations of VOCs and metals were detected in ground water in the alluvial aquifer
to the northeast, east, and south of the ponds. Samples from a monitoring well screened in
the upper bedrock aquifer (the Fort Riley Limestone) also contained elevated concentrations
of VOCs and slightly elevated levels of metals relative to background. No contaminants
were detected in the lower bedrock aquifer (the Florence Limestone).
Samples collected from a spring emanating from the west bank of the river northeast of the
ponds contained VOCs and SVOCs at concentrations slightly above analytical detection
limits. A ground water seep located northeast of the Site at the southwest edge of the river
showed elevated concentrations of SVOCs and metals. Many of the contaminants detected
in the seep are consistent with the contaminants detected in the sludge. No VOCs were
detected in the seep.
5.3 OU1 FEASIBILITY STUDY
The original FS evaluated five general response actions which could be applied to the
contaminated media and conditions known to exist at the Site. The general response
categories included: (1) no action: (2) reuse; (3) capping; (4) stabilization; and (5) thermal
treatment. The FS identified and screened remedial action technologies associated with each
general response action previously identified. The screening criteria used for the analysis
included effectiveness, implementability, and cost of each remedial action technology.
Those remedial action technologies failing to meet the pre-defined criteria were screened out
of the process.
Remedial action technologies were screened for applicability to the specific affected media
types (sludge and soil). The remedial action technologies evaluated for sludge included: (1)
no action; (2) reuse in asphalt or refinery; (3) capping; (4) stabilization on or off site; (5)
thermal treatment on or off site; (6) bioremediation; and (7) removal/landfill. The remedial
action technologies evaluated for soil included: (1) no action; (2) capping; (3) stabilization
on or off site; (4) thermal treatment on or off site: (5) bioremediation; (6) removal/landfill:
and (7) in situ O'in place") soil flushing.
Several remedial alternatives combining the technologies and process options that passed
initial screening were evaluated in the FS report. The EPA ROD split the Site into two
operable units and selected removal and reuse of sludge at a refinery followed by in situ
flushing/bioremediation of the remaining soils as the remedy for the sludge and soil operable
unit. The existing interceptor trench was incorporated into the treatment of the soil; seepage
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from the ponds that is captured in the interceptor trench system is currently being
recirculated into the ponds.
It was determined subsequent to the execution of the ROD that the remedy described therein
was not impiementable because there were no available refineries which held a permit to
accept off-site Resource Conservation and Recovery Act (RCRA) hazardous wastes for
recycling, making the transportation of sludge materials off site infeasible. An Explanation
of Significant Differences (ESD) was prepared to document changes to the ROD and the
reasons those changes were made. The remedy \vas modified by the ESD to incorporate an
alternative method of treating the sludge material. The modified remedy included three-
phase separation of the pond sludge on site. The water phase was to be sent to the Coastal
Derby wastewater treatment plant which operates under a NPDES permit. The oily phase
was to be taken off site to be recycled. The residual solids, or "filter cake", were to be
further treated on site to meet Best Demonstrated Available Technology standards to meet
the land ban requirement for land disposal. The treated filter cake was then to be disposed
at a RCRA-permitted Treatment. Storage, and Disposal facility in compliance with EP.Vs
off-site policy.
5.4 OU2 FOCUSED/ABBREVIATED REMEDIAL INVESTIGATION
The Focused/Abbreviated RI for OU2 of the Site (OU2 RI) was directed toward augmenting
information on the nature and distribution of groundwater and groundwater contamination
at the Site collected during the original Site-wide RI. Fina retained Sharp and Associates.
Inc. (Sharp) to perform the OU2 RI/FS activities. Sharp identified the following goals for
theOU2RI:
• to gain further understanding of groundwater flow at the Site:
• to assess interaction between aquifers: and
• to define the extent of groundwater contamination.
The field work for completion of the OU2 RI was conducted in June 1994.
The following three aquifer units were defined for OU2:
alluvial;
upper bedrock (Fort Riley Limestone); and
lower bedrock (Florence Limestone).
Ground water flow in the alluvial and weathered zone of the upper bedrock aquifers was
generally to the northeast toward the West Branch Walnut River. The lower portion of the
upper bedrock aquifer also flowed from the Site to the east in the direction of bedrock dip.
A well on the east side of the river indicated that the ground water flow direction in the
upper bedrock aquifer in that area is also toward the river.
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A hydrologic connection between the alluvial aquifer and the upper portion of" the upper
bedrock aquil'er was inferred due to similar potentiometric surfaces, i.e.. ground water in the
two aquifers is mingled. The alluvial aquifer and the upper portion of the upper bedrock
aquifer flow toward the river which acts as a hydrologic sink or a gaining stream. The lower
bedrock aquifer exhibited artesian (confined) conditions due to the presence of an aquiclude
(Oketo Shale) between the upper and lower bedrock aquifers.
Contamination was generally confined to the alluvial and upper section of the upper bedrock
aquifer. The lower bedrock aquifer was free of contaminants in excess of MCLs. Further
discussion of the occurrence of ground water contaminants in the aquifers is included in
Section 6.1 below.
Figure 4 illustrates the burn pond, surrounding active wastewater ponds and the monitoring
wells in the area. There are three potential sources for ground water contamination in the
alluvial aquifer on and off site: the bum pond, the existing refinery located upgradient of the
Site, and the active refinery wastewater treatment ponds south of the Site.
To resolve the potential upgradient contaminant source at the existing refinery, well W38
was drilled during the OU2 RI. Well W38 is hydraulically upgradiem of wells W23. W24.
and the piezometers nearest to the ponds (P3, P4, and P5). Well W38 contained
substantially higher concentrationsof dissol ved-phase BTEX contamination than wells W23
and W24. The OU2 RI concluded that the contamination in W38 is related to a source
upgradient of the Site. KDHE is in the process of evaluating this area with the current
refinery operator.
Another area of potential contamination exists south of the bum pond in the vicinity of wells
W3 and W22. Additional piezometers (P6. P7, and P8) were installed to resolve the ground
water flow direction in the alluvial aquifer. Based on the June 1994 alluvial potentiometric
map, the ground water in the vicinity of the final refinery wastewater treatment pond and the
south end of the burn pond flows toward the river (see Figure 5). The active wastewater
treatment ponds at the Coastal refinery also contain oil being treated through an
aeration/biodegradation process. The conclusion drawn in the OU2 RI from these data is
that the wastewater ponds may be potential contributors to ground water contamination in
the vicinity of well W22. The separation of dissolved phase contamination plumes in the
alluvial aquifer at the southern boundary of the Site is based on ground water flow potential
rather than chemical composition because there was no distinct chemical fingerprint for
either potential source to distinguish between the two.
A summary of the major contaminants and maximum concentrations in the June 1994
samples by aquifer is shown on Table 1. Figure 6 illustrates a conceptual cross-section of
contaminant distribution in OU2.
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Contamination in the alluvial aquifer, which is not considered a drinking water aquifer based
on potential yield and inorganic quality, extends from the upgradient edge of the Site
property to the river to the east and north and to the southern property boundary to the south
based on flow direction. The existing subsurface interceptor trench which was constructed
in connection with the GUI remedy serves as a barrier to ground water contaminant
migration to the river. The alluvial aquifer terminates at the river. The highest
concentrations of VOCs were present in the alluvial aquifer. VOCs identified in the alluvial
aquifer during the OU2 RI included benzene, ethylbenzene. toluene, and total xylenes.
Benzene is present at concentrations in excess of the MCL. SVOCs identified in the alluvial
aquifer included low concentrations of polycyclic aromatic hydrocarbon compounds.
phenols, phthalates. naphthalene, and methylnaphthalene. Arsenic, barium, chromium, and
lead were present above background concentrations in the alluvial aquifer. Separate-phase
hydrocarbons were present in several wells during the OU2 RI sampling.
The upper bedrock aquifer | Fort Riley Limestone) is locally recharged by the ponds on the
Site. Ground water is interpreted as flowing north and east from the ponds and discharging
to the West Branch Walnut River. Trace concentrations of benzene, toluene, and total
xylenes were detected in a well completed in the upper bedrock aquifer upgradient of the
Site in 1990. No VOCs were detected in the sample collected from the upgradient well
during the OU2 RI except acetone which was tentatively attributed to laboratory
contamination. A sample collected in 1990 from a well located downgradient of the burn
pond and screened in the upper bedrock aquifer contained higher levels of benzene, toluene.
and total xylenes relative to the upgradient well and low levels of arsenic and barium:
subsequent samples have not contained elevated concentrations of metals or VOCs. Low
concentrations of several SVOCs were detected in the upper bedrock aquifer during the 1994
OU2RI.
The lower bedrock aquifer (Florence Limestone) is separated from the upper bedrock aquifer
by an aquiclude. the Oketo Shale. A background sample collected in the lower bedrock
aquifer in 1990 contained trace concentrations of toluene and total xylenes: no VOCs were
detected above detection limits at this location during the OU2 RI. Samples collected from
a well completed in the lower bedrock aquifer downgradient of the ponds contained no
VOCs or SVOCs above detection limits. Arsenic and barium were detected at
concentrations below the MCLs for those substances in 1994 and may reflect the naturally-
occurring background concentrations for those metals in the aquifer.
Surface water samples were collected from the West Branch Walnut River during the OU2
RI and analyzed for VOCs; no VOCs were present above detection limits.
A subsurface interceptor trench exists at the Site to prevent further migration of
contaminated ground water. The interceptor trench was designed to capture and recirculate
seeps from the ponds to maintain the aqueous bioremediation system: the trench also serves
to contain the ground water plume and to prevent further migration of contaminated ground
10
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water from the hydraulically connected alluvial ana upper bedrock aquifers to the river. The
number of oily seeps discharging to the river east of the interceptor trench decreased arier
its installation. No oily seeps have- been noted along the river bank adjacent to the Site
during recent inspections.
Both a step test and a constant rate aquifer pumping test were conducted on the trench in
June 1994. The connection between the alluvial aquifer and upper portion of the upper
bedrock aquifer was confirmed as well as the connection to the river. A hydraulic
conductivity of 3.7.X10"1 cm/s was determined. During active pumping in the trench, the
ground water flow direction between the trench and the river reverses toward the trench.
The effectiveness of the interceptor trench was evaluated. The east side of the trench acts
as a partial barrier to ground water migration due to the presence of a liner installed into the
bedrock surface. This barrier was found to be approximately 20% effective at preventing
ground water migration with the pumps off and 130% effective with the pumps on. meaning
that with the pumps operating the trench not only prevented water from flowing
downgradient but actually drew some water from the downgradient side of the liner. A
pumping rate of 12 gallons per minute was determined to be sufficient to exert hydraulic
control over the length of the trench.
6.0 SUMMARY OF SITE RISKS
6.1 THE RISK ASSESSMENT
As part of the RI/FS, a Risk Assessment (RA) for OU2 was prepared by PRC
Environmental Management, Inc. on behalf of KDHE. The OU2 RA was carried out to
characterize, in the absence of remedial action, the current and potential threats to human
health and the environment that may be posed by contaminants released from the ponds and
their impacts to ground water and surface water. The RA provides information to help
determine whether remedial action is necessary for OU2 of the Site .
The OU2 RA is primarily based on sample data collected from the Site during the OU2 RI.
Ground water and surface water data were collected during the RI. Contaminants detected
in these media were used to characterize the nature and extent of the human and ecological
risks posed by OU2.
For this risk assessment. PRC evaluated data from three aquifers: alluvial, upper bedrock.
and lower bedrock. The aquifer with the highest number of contaminants and the highest
concentrations was the alluvial aquifer: this aquifer was the focus of the risk assessment.
Chemicals of potential concern found in the Pester Refinery Co. OU2 are VOCs and metals.
Ground water data showed the major contaminants to be benzene, toluene, ethylbenzene.
11
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xylenes. naphthalene, and arsenic. A total of 18 substances were evaluated in the RA as
chemicals 01'potential concern in ground water isoe Table 2).
Surface water samples were collected from the West Branch Walnut River during the OU2
RJ: surface water sampling showed no detectable concentrations of COCs.
Pathways by which humans could be exposed to the chemicals of potential concern in
ground water at the Site were evaluated based on reasonable assumptions about current and
future land use. The exposure assessment identified receptors thai potentially may be
exposed to contaminants. Future on-site workers and future residents were evaluated as
receptors that might receive exposure to site contaminants. It should be noted that.
consistent with the OU1 ROD for soil and sludge, deed restrictions have been emplaced on
the property that prevent future use of the Site for residential purposes; consequently, an
industrial land-use scenario was used as the standard for remedy evaluation for OU2. The
Site is presently being used for industrial purposes, although industrial activities are limited
to maintenance of the ponds and the interceptor trench. The Site property is currently zoned
industrial. The Site is also fenced and posted with warnings to prevent trespass. Future
residential exposure scenarios will not be further considered in this document.
For future worker exposures, the OU2 RA assumed that ground water from the alluvial
aquifer would be used and that workers would be exposed through ingestion, dermal contact.
and inhalation of volatilized contaminants during showering. The RA characterized this
assumption as conservative since City of El Dorado Public Water Supply water is available
at the Site.
Available risk factors for carcinogens and noncarcinogens were obtained from the EPA
Integrated Risk Information System (IRIS) and the Superfund Technical Support Center
Environmental Criteria and Assessment Office Risk Assessment Issue Paper for: Provisional
Oral Reference Dose for Naphthalene for the chemicals of potential concern in OU2. The
majority of the chemicals of potential concern have a noncarcinogenic effect on humans:
only benzene and arsenic are carcinogenic.
A Hazard Index (HI) was calculated for each pathway evaluated in the OU2 RA. A HI of
less than 1 indicates that the noncarcinogenic risks associated with that pathway are within
the acceptable range for human health risk as determined by EPA. The HI for on-site
workers did exceed 1 for the ground water ingestion exposure pathway as evaluated for
exposure to contaminants in the alluvial aquifers. Arsenic was the most significant
contributor. Barium, chromium, and 2-methylnaphthalene were more significant
contributors to non-carcinogenic risk than the remaining chemicals of potential concern.
The carcinogenic risks were also calculated for the evaluated pathways in OU2. The
carcinogenic risk from exposure to a chemical is described in terms of the probability that
an individual receiving chronic exposure to the chemical will develop cancer as a result of
12
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that exposure. Risk estimates are presented as excess cancer risk per unit of population. For
example, a risk estimate of 1 X 10" is equivalent to a risk of one excess occurrence ofcancer
per 10.000 exposed individuals in a ^iven population.
The total excess lifetime cancer risk for future on-site workers was estimated for exposure
to ground water from the alluvial aquifer. The highest cancer risk was seen to the future
worker ingesting ground water. 6.7 X 10'5. The cancer risk for dermal contact by future on-
site workers was 2.7 X 10'". That for inhalation during showering by future on-site workers
was 3 X 10°. The total cancer risk for all exposure pathways involving future on-site
workers was 1 X 10"4. The contaminants contributing most to these risks were arsenic and
benzene.
PRC did not calculate potential risk resulting from human exposure to ground water in the
bedrock aquifers. The chemicals found in the upper and lower bedrock aquifers were
limited and at concentrations two orders of magnitude lower than levels found in the alluvial
aquifer. This indicates that risk associated with exposure to the bedrock aquifers would be
significantly less than that posed by contamination in the alluvial aquifer.
EPA uses the general 1 X 10'4 (one in 10.000) to 1 X 10'6 (1 in 1.000.000) lifetime excess
cancer risk range as a "target range'' within which the EPA strives to manage risks as pan
of a Superfund cleanup. Generally, where the risk assessment indicates that a cumulative
site risk to an individual using reasonable maximum exposure assumptions for either current
or future land use exceeds the 10"* lifetime excess cancer risk end of the risk range, action
under CERCLA is warranted at the Site. Although the National Contingency Plan (NCP)
suggests the 10"6 level as a starting point for acceptable risk, a site-specific risk estimate
around 1 X 10"1 may be considered acceptable if justified based on site-specific conditions.
For sites where the cumulative site risk to an individual based on reasonable maximum
exposure for both current and future land use is less than 1 X 10"4, action generally is not
warranted, but may be warranted if a chemical-specific standard that defines acceptable risk
is violated, noncarcinogenic risk falls within an unacceptable range, or an adverse
environmental impact exists that warrants action. It should be noted that the calculation of
potential risk posed by ground water contamination at the Site in the OU2 RA should
probably be viewed as overly conservative, since the projected maximum sustained yield of
the combined alluvial and upper bedrock water-bearing zones would be insufficient to serve
as a permitted domestic water supply in Kansas, and the ingestion of. dermal contact with,
and inhalation of contamination from those zones by future workers is consequently unlikely
to occur.
6.2 CONTAMINANT TRANSPORT
The original source of contaminants at the Site was the burn pond sludge, now removed
from the Site, which contained volatile and semi-volatile organic compounds as well as
several metals. The first 12 to 24 inches of soil beneath the ponds were stained as a result
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or" contamination, as were up to 5 feet ol" soii in the bottom or" the aquifer between the
eastern boundary of the bum pond and the river. The amount ot contaminated soil was
'iriginaiiy estimated at 70.UUO cubic \ards.
Based on the findings ofthe OU2 RI. transpon ot" contaminants t'rom the burn pond sludge
through the vadose zone to ground water has occurred. Ground water Hows radially to the
north, east, and south from the burn pond in the alluvial aquifer and discharges into the West
Branch Walnut River. The ground water flow velocity through the alluvial aquifer is
estimated to range from 0.2 to 60 meters/year depending on whether water is moving within
the silty clay or through local clayey gravels. The rate of contaminant migration will be
highest in the gravel-rich zones within the alluvial sediments.
Benzene, toluene, xylene. arsenic, and barium were identified in the Fort Riley aquifer in
wells located downgradient of the bum pond area. This condition indicates that
contamination has migrated from the ponds and the alluvial aquifer to the Fort Riley
limestone. The Fort Riley limestone aquifer also discharges to the West Branch Walnut
River.
No chemicals of concern for the Site have been detected at significant concentrations in the
Florence Limestone aquifer. A sample collected in 1994 from the Florence Limestone
contained slightly elevated concentrations of arsenic and barium (below their respective
MCLs), but those detections may reflect the naturally-occurring background concentrations
for those metals in the aquifer. The presence of the shale zone within the Fort Riley
Limestone appears to act as an aquitard, isolating the Florence Limestone to some extent
from the downward migration of contaminants present in the overlying aquifers. Trace
concentrations of toluene and total xylenes were detected in a background sample collected
from the Florence Limestone downgradient of the adjacent refinery and upgradient of the
Site in 1990. suggesting that there may be some limited communication between the
overlying saturated zones and the Florence Limestone.
Oil and dissolved-phasecontaminationis accumulating in the subsurface interceptor trenches
on the east, northeast, and north sides of the ponds. The contaminants appear to migrate to
the top of the bedrock surface and then travel via gravity to subsurface topographic
depressions. The bedrock slopes to the east and has a surface exposure on the north side of
the Site. The subsurface interceptor trenches are completed into the bedrock surface.
Migration is believed to be due at least in part to the hydraulic head supplied by the water
in the ponds.
Organic chemical contamination was detected in the alluvial sediments in 1986, indicating
that contamination has migrated via surface runoff, aquifer/stream interconnection, or trench
overflow events into the West Branch Walnut River.
14
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6.3 ECOLOGICAL RISKS
The data trom \hc sue \\ere lunued tor evaluaiiny the potential ecological risks posed by
contamination m OU2. At the time ot'the RA preparation there were seeps discharging to
the West Branch Walnut River: however, those that are adjacent to the ponds have seen a
significant decrease in How since the installation or' the interceptor trench. No seeps are
visible at this time. No VOC contamination has been detected in surface water during recent
sampling events. There are no current data available for the sediments, although it is
anticipated that S VOCs could accumulate in the sediments. Based on the available data, no
impacts to the ecosystem have been detected.
The environmental receptors in the vicinity of the Site include common wildlife such as
rabbits, snakes, migrating waterfowl, and aquatic life, including fish. Wildlife might be
affected by exposure to contaminated sediments or surface water in the West Branch Walnut
River.
An Ecological Assessment (EA) was conducted as a part of the OU1 Rl/FS for the purposes
of determining possible effects from contamination to the Site ecological system. The EA
states that there is a possibility that wildlife accessing the bum pond area could be affected.
but that the severity of the effect could not be quantified without further information. Any
effect would be dependent upon wildlife accessing and using the area and ingesting
significant quantities of contaminated material. Contaminated ground water was not
indicated as a threat to animal life in the vicinity of the Site. Three endangered species, the
bald eagle and two species of snake, are mentioned in the EA as located near the Site. Bald
eagles are known to winter in El Dorado State Park one mile from the Site. The two species
of snake. Heterodon platyrhinos and H. hasicus. have verified locations from counties on
three sides of Butler County (Harvey. Cowley and Greenwood counties).
The EA determined that the principal on-site ecological threat was posed by the sludge
contained in the bum pond. The sludge has been treated and removed from the Site and
stained soils within the bum pond are being addressed through bioremediation consistent
with the OU1 ROD.
6.4 REMEDIATION GOALS
Remediation goals for OU2 have been defined on the basis of the OU2 RI/FS findings in
conjunction with the conclusions of the OU2 RA. The OU2 RA established that, for the
Ground Water Operable Unit, the total excess lifetime cancer risk posed by all exposure
pathways involving future on-site workers was 1 X 10"4. The cumulative HI for all non-
carcinogenic chemicals of concern was determined during the OU2 RA to exceed the
threshold criteria of 1.0. These risks are based on exposure to contamination identified in
the alluvial aquifer. The concentrations of contaminants in the upper bedrock aquifer (the
Fort Riley Limestone) were lower than those in the alluvial aquifer upon which the findings
15
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of the OU2 RA uere based. No significant contamination lias been detected in the lower
bedrock aquifer (the Florence Limestone). The risk evaluated forOL'2 during the OL'2 RA
have been ettectiveiy eliminated by existing institutional controls that uere implemented as
aspects ot'the OU1 remedy: i.e.. the deed restriction preventing development of the property
tor residential purposes and the presence of a maintained fence to control access to the Site.
Furthermore, the alluvial aquifer that was evaluated in the OU2 RA is not used as drinking
water sources in the vicinity of the Site, and the OU2 RI/'FS indicates thai the combined
alluvial and upper bedrock aquifers would not yield sufficient water at the Site to serve as
a domestic water supply source, and may be non-potable due to background inorganic
quality issues. While a hydrologic connection has been determined to exist between the
contaminated alluvial aquifer and the less-contaminated upper bedrock aquifer, the lower
bedrock aquifer, which may serve as a drinking water source in the region, is separated from
the upper bedrock aquifer by a competent shale confining layer and exhibits artesian
properties on site: in other words, ground water in the upper two aquifers can mingle, but
ground water in the lower bedrock aquifer appears to be geologically isolated from the upper
aquifers. Finally, while no supporting analytical evidence is available at this time, the
operation of the underground interceptor as an aspect of the GUI remedy is probably
reducing the concentrations of ground water contaminants in the alluvial aquifer through the
removal of oil and the filtration of particulates: ground water monitoring included as a
component of the selected remedy for OU2 will confirm this contaminant reduction. KDHE
and EPA have therefore concluded that ground water contamination in the alluvial aquifer
does not pose unacceptable risk to human health.
Unacceptable potential risk could be posed if contamination from the alluvial and upper
bedrock aquifers were to impact the lower bedrock aquifer. As a drinking water aquifer, the
relevant and appropriate water quality standards for the lower bedrock aquifer are MCLs.
Primary remediation goals for OU2 are therefore to monitor the lower bedrock aquifer to
make sure that contaminant levels do not trend upward, so that it does not become
contaminated in excess of MCLs for the chemicals of concern in OU2: and to prevent future
human exposure to contaminated ground water within the upper bedrock and alluvial
aquifers. Ideally this latter goal would be accomplished by reducing the concentrations of
contaminants in the overlying aquifers to concentrations that no longer pose a significant
threat to human health or water quality in the lower bedrock aquifer. While KDHE and EPA
have determined that the potential risk posed by ground water contamination in the upper
saturated zones at the Site does not warrant a ground water remedy, operation of the
interceptor trench and the treatment of the trench effluent that is being performed as an
aspect of the OU1 flushing/bioremediation remedy will probably continue to reduce the
concentrations of chemicals of concern in those saturated zones.
Significant Remedial Action Objectives (RAOs) identified in the OU2 FS for OU2 included:
1) reducing contamination in environmental media with completed exposure pathways such
that the cumulative HI is less than 1 and the cumulative excess lifetime cancer risk is less
than 1 X 10"1: 2) protecting the Florence Limestone bedrock drinking water aquifer from
16
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becoming contaminated in excessof MCLs; 3) preventing separate-phase hydrocarbons from
entering the \Vest Branch Walnut River: and -) preventing uater with levels of
contamination above the appiicabie uaier quality standards from discharging into the West
Branch Walnut River. As previously indicated, no completed exposure pathways currently
exist for contaminated ground water at the Site, and the existing institutional controls
effectively eliminate the potential risk posed by exposure to contaminated ground water.
The operation of the underground interceptor trench as part of the OU1 remedy prevents the
discharge of separate-phase hydrocarbonsorsigniftcantconcentrationsof other contaminants
to the river.
The primary remediation goals that remain are therefore to prevent degradation of water
quality in the lower bedrock aquifer by the chemicals of potential concern, prevent the
degradation of surface water quality in excess of applicable surface water quality standards.
and prevent the discharge of visible films resulting from seeps of separate-phase
hydrocarbons into the river. An additional remedial goal, to prevent human ingestion of
ground water from the alluvial aquifer that exceeds acceptable risk levels, has been
determined by KDHE and EPA to not apply to the Site: however, this goal will be met
through the device of institutional controls (i.e.. the existing deed restriction preventing the
use of the Site property for other than industrial uses and the existing site access controls)
and through the ongoing operation of the subsurface interceptor trench as an aspect of the
OUl ROD. In addition, though not required for protection of human health and the
environment. KDHE has requested that the property owner amend the existing deed
restriction to include a restriction preventing the installation of water wells for purposes
other than remediation as an additional conservative measure. This restriction will run with
the property and could only be removed with KDHE's consent.
In summary, because the risk from ground water falls within EPA's acceptable range.
KDHE and EPA believe no further action is necessary to protect human health and the
environment from exposure to the ground water at the Site. In addition, the fact that the
alluvial aquifer is not a usable drinking water source, the expectation that contamination
levels at the Site will probably continue to reduce as a result of the OUl remediation
activities, and the belief that the operation of the seepage interceptor trench as a component
of the OUl remedy is effectively preventing any off-site migration of contaminated water,
and that institutional controls will prevent any future well drilling at the Site contribute to
KDHE's and EPA's belief that no additional measures are necessary at the Site at this time.
Based on the conclusions of the OU2 RA and the OU2 RI/FS, the identification of response
objectives, and the identification and evaluation of potential response actions, KDHE and
EPA have determined that no additional action other than ground water monitoring and
sediment sampling is necessary for the Ground Water Operable Unit of the Pester Refinery
Co. Site to protect human health and the environment. If future monitoring of the Florence
17
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Limestone aquifer were to indicate a consistent trend toward increases in (he concentrations
oi chemicals of concern. >m active remedy uill he warranted. Nmilarly. if sediment
sampling in the West Branch \Valnut River were to indicate significant impacts related to
historical Site activities, additional assessment or remedial action will be warranted.
7.0 DESCRIPTION OF THE SELECTED "NO ACTION" REMEDY
The OU2 FS evaluated several different remedial alternatives including the "No Action" alternative
for the Ground Water Operable Unit of the Pester Refinery Co. Site based on the findings of the
OU2 RI. Details of the remedy evaluation are included in the OU2 RI and FS in the Administrative
Record file for the Site.
The selected "No Action" remedy for OU2 will involve no additional measures to eliminate, reduce.
or control threats to human health and the environment other than mitigative measures implemented
as components of the GUI ROD. Those measures include institutional controls in the form of a
deed restriction controlling development of the property and a fence to restrict site access, the
treatment and/or removal of the source material (oily sludge in the ponds), and the operation of the
underground interceptor trench. The underground interceptor trench was constructed to prevent
separate-phase hydrocarbon and dissolved-phase seeps from the ponds from reaching the river and
to recirculate trench effluent to the ponds to maintain the aqueous bioremediation system. KDHE
and EPA anticipate that the process of extracting, treating, and returning the seep water to the ponds
for recirculation will also reduce the concentrations of contaminants in ground water through oil-
water separation, physical filtration, biodegradation, and other natural attenuation processes.
Though not required for protection of human health and the environment. KDHE has requested that
the properly owner amend the existing deed restriction to include a restriction preventing the
installation of water wells for purposes other than remediation as an additional conservative
measure. This restriction will run with the property and could only be removed with KDHE's
consent.
Actions to be taken under the selected "No Action" remedial alternative will consist of ground water
monitoring and sediment sampling. Ground water monitoring of the alluvial, upper bedrock, and
lower bedrock aquifers will be conducted to verify that the concentrations of contaminants in the
alluvial aquifer and the upper bedrock aquifer (the Fort Riley Limestone) continue to decline and
that the concentrations of the chemicals of concern (Table 2) in the Florence Limestone drinking
water aquifer do not increase. Sediment sampling in the West Branch Walnut River will be
conducted to augment the limited information on potential impacts historical releases from the Site
may have had on the river. Ground water monitoring and sediment sampling will be conducted on
a quarterly basis to provide a clearer assessment of baseline conditions, account for seasonal
variations in ground water level and contaminant concentrations, and permit an assessment of the
effectiveness of the OU1 remedy in concomitantly restoring the ground water conditions at the Site
18
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and protecting the West Branch Walnut River. Alter tun years, the frequency of monitoring and
sediment sampling uill be re-evaluated hy KDHE and 1:PA.
As required by CERCLA lor sites where any hazardous substances, pollutants, or contaminants
remain on site, reviews of the remedy must be conducted by KDHE and EPA at least ever,' five
years after the initiation of the remedy to verify that human health and the environment are being
protected by the remedy. For sites with multiple operable units, one five-year review will be
conducted for the combined operable units: consequently, the first five-year review for OU1 and
OU2 of the Site will be conducted no later than five years from the initiation of the remedial action
for OU1. and an additional five-year review will be conducted at least every five years thereafter.
The five-year reviews will continue as long as hazardous substances remain on site.
8.0 SIGNIFICANT CHANGES FROM THE PROPOSED PLAN
The Proposed Plan for the Ground Water Operable Unit of the Pester Refinery Co./Pester Burn Pond
Site was released for comment in August 1998. That Proposed Plan identified the No Action
alternative as the preferred alternative for OU2. Public comments on the Proposed Plan were
evaluated at the end of the public comment period and are addressed in the attached Responsiveness
Summary. This Record of Decision proposes no significant changes for OU2 from the alternative
presented in the Proposed Plan.
19
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Fieure 1
PESTER BURN POND SUPERFUND SITE LOCATION MAP
.;7"xx
Pester'BiirfirPon&Site
» V £P«t • *—I—^2rC5*«3«*. «^ss
^" v^-NT^^^S
^4 -^. rs;^:U§^s^
I'-li i.
i ^ i_fe*
Pester Burn Pond Superfund Site, El Dorado, Kansas
Site Location Map
county
Scale 1:24,000
y -
Location
Source: U.S.G.S. IS Topographic Quidnngic. El Dorado. Kansas. 1961. phoorevised I9T9
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FIGURE:
Pester Burn Pond Superfund Site and Vicinity
Pester Bum Pond Site
Wastewater
Trea
Plan
Coastal
Refinery
o
Union
ank
Company
Coastal
Tank Farm
Tank Car
Residences
•Mioscafe
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Figui 3
Geologic Cross Section of Ihc Pester Burn Pond Supcrfund Site
El Dorado, Kansas
Source:
Remedial Investigation Report for the Pester Unrn Pond She (Opcrnble Unit 11
*••• • • • • • » « *»r» t *\f\ • . . ' iii it i oo I
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-l_-^~ V
Figure 4
Site Features Map
Pester Refinery Co. Sice
El Dorado, Kansas
Un« M UM four Bum rood Su«. El DonM. K
Slw* IM A'T-ifM. lix. April 11. 1995.
Ocuter 19. 1995
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\ \ i . 5*0" •nucmoii
\ \ A \ .'•*i-L.
Figure 5
Alluvial Aquifer Potentiometric
Surface Map. 6/17/94
Paid Ririnuv Co. S.(«. El Danao. Kiniu
iu>arAbflr««i«i«4 tuncOMI
nv«s(i|liiOA'Hcpa#l of UK Ground Wucr OoweM
Unit tt I/M ftaiu Bun Pond SKC. El Dorado.
S^«rp tna AIMCIMM. Utc.. Apfil 11. 1991.
Ocuwcr l«. 199]
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KOXCttD
•MO
1320
IJIO
1300
1290
1260
1270
1260
1250
KfltfXD
IIII-I23I
240
(.
T» V ~~
, , tO»0CC UMfTOX vrKSri
HO UM-VQUIkQ
-
' — -12*0
SCTltMO
un-oo<
10-ii
| | | • | | | -) 1 1 | | I4JU
) 100 20O 300 400 500 600 700 BOO 900 1000 1 IOO 1200
DISTANCE (FT) TAKEN FROM WILSON * co «/a& sunvrr
h
L
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Table 1
Summary of Compounds Detected in Ground Water
Maximum Concentrations - June 1994 Sampling Event
Pester Bum Pono Superfund Site
Ei Doraao, Kansas
.'.,•:-:• •:-'-: »'£['•-?:•. -
.-'•„' .CooDOorid'. ..*.>> MCL
VOCi
Acetone
Benzene
Toluene
Ethvibcnzene
Xyjenes. total
Carbon Disulfide
SVOCs
* :;;--•-,:-;.•, ::.V:.:.--.'
1 * - - Alluvial Aauifer- .-'*-•
i
NE
5 '
1000
700
10.000
NE
i
I
1
I
1
1
46
230
9
24
48
120
, Foctfiife; Aquifer t -...• Ftorenee Limestone
? (Upper BedrockV F i7' (LowerBedrockV." •
30
<5
<5
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Table 2
Chemicals of Potential Concern
Pester Bum Pond Superfunri Site
El Dorado, Kansas
Chemicals of Concern
Acenaphthene
Arsenic
Banum
Benzene
Carbon Disulnde
Chromium
Dibenzofuran
Dimethyl Phthalate
2.4-Diraethylphenol
Etbylbenzene
Fluorene
Le^d
2-Methylnapbtbalene
Naphthalene
Pheoanthrene
Phenol
Toluene
Xylene
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RECORD OF DECISION
PESTER REFINERY CO./PESTER BURN POND SITE
GROUND WATER OPERABLE UNIT
El Dorado. Kansas
RESPONSIVENESS SUMMARY
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1.0 Introduction
Fhis Response oness Summary for the i) round Water * >perable \ 'nit (01 '21 of the Pester Refinery
Co.. Pester Bum Pond Site responds to comments received during the formal public comment period
on the August 2". 1998. Proposed Plan of Action. The Proposed Plan described the Environmental
Protection Agency iEPA) and Kansas Department of Health and Environment (KDHE) proposal
for remediation strategy for OU2. This summary also presents EPA and KDHE responses to
comments received during the formal public comment period from August 21 to September 26.
1998.
On September 2. 1998. a public meeting was held at the Bradford Memorial Library in El Dorado.
Kansas, to present the Proposed Plan forOU2 and a concurrently offered Explanation of Significant
Differences for OU1. Notice for a 30-day public comment period and the public meeting was
published in the El Dorado Times and was provided to a number of local and regional public and
private entities that might have interest in the Site. No oral comments were received during the
public meeting: transcripts of the meeting have been added to the Administrative Record for the
Site. Information repositories containing the Administrative Record for the Site are available at the
Bradford Memorial Library in El Dorado, at the KDHE office at Forbes Field in Topeka. and at the
EPA Region VII office in Kansas City. Kansas.
Pursuant to Section 117 of the Comprehensive Environmental Response. Compensation and
Liability Act (CERCLA. or Superfund). 42 U.S.C § 9617. EPA and KDHE considered all of the
comments received during the public comment period in making the final decisions for OU2. This
Responsiveness Summary is part of the Administrative Record for the site and an attachment to the
Record of Decision (ROD) for the Site.
2.0 Stakeholder Issues and EPA Responses
No oral comments were presented by any interested parties at the September 2. 1998. public
meeting. Several written comments were received during the formal public comment period:
summaries of these comments and the EPA and KDHE responses are included below.
Comment from the City of El Dorado: The City of El Dorado reports that periodically their
wastewater treatment plant operators have noted oil sheens on the West Branch Walnut River
while performing river gauging at some distance downstream of the Site. The City goes on to
recommend that testing be conducted upstream and downstream of the Site. "This testing
(biomonitoring) may be instrumental in detecting damage to the aquatic life in the west branch
of the Walnut River, and also in pinpointing a source of contamination that might possibly be
blamed on the El Dorado Wastewater Treatment Plant some time in the future."
Response: It is unclear from the City's comment whether the reported incidences of oil sheens
on the West Branch Walnut River are directly attributable to the Pester Burn Pond Site. It
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should be noted that there are a number ot other current and historical potential sources tor lou-
\olume seepage releases to tiie river, including many decades oI crude oil exploration and
production along the entire reach ot the West Branch \Vuinut River. The Pester Burn Pond Site
is unique among industrial facilities along the lower reach 01 the river in that an active hydraulic
control system is operating at the Site to prevent the discharge ot'separate-phase hydrocarbon
seeps to the river. While the Site had historically resulted in the discharge of oily-phase material
from ground water to the river, those seeps have decreased dramatically since the installation of
the underground interceptor trench, and inspections within the last year have not identified any
seeps along the reach of the river adjacent to the Site.
The EPA and KDHE do not believe that biomonitoring of the West Branch Walnut River is
necessary at this time as a feature of the Pester Bum Pond Site remedy. No seeps are currently
observed from the Site. Surface water sampling conducted as pan of the 1994 OU2 Remedial
Investigation did not detect any VOCs in the river. The OU2 Risk Assessment concluded, based
on the limited data available for the Site, that the primary on-site ecological risk was due to the
sludge in the ponds, which have been removed as pan of the Soil and Sludge Operable Unit
remedy. Again, although Site conditions have historically resulted in the discharge of oily
wastes to the river, given the nature of current and historical operations along the river, it seems
unlikely based on recent observations that any downstream impacts to the river can be clearly
attributed to the Pester Bum Pond Site alone; furthermore, this Site has an active system in place
to prevent any future discharges to the river other than those permitted under the substantive
requirements of the National Pollution Discharge Elimination System (NPDES).
Sediment sampling will be conducted along the West Branch Walnut River as pan of the
selected "No Action" remedy for the Site to augment the limited information available on
impacts the Site may have had on the river. The identification of a significant trend in
enrichment of site contaminants in the river sediments could trigger additional characterization
of the impact the Site has had on the river and its aquatic biota.
As a preliminary suggestion, it would be helpful for the City employees to repon the occurrence
and location of anv observed oil sheens to the KDHE South Central District Office in Wichita
*
for investigation. District office staff may be able to identify the source of an active discharge if
the discharge is reported in a timely manner. In the meantime, the City's comment will be
forwarded to the KDHE Bureau of Environmental Field Services for possible follow-up.
Comment from Danny R. Kite, Fina Oil and Chemical Company: The steady state pumping
rate for the underground interceptor trench should be 12 gallons per minute rather than the 17
gallons per minute rate stated in the Proposed Plan on page 11.
Response: The text of the ROD has been modified to reflect the correct steady state pumping
rate for the underground interceptor trench.
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(..'ommam from (. T Dickcrson. ('oustai Refining and \lurkeiing. Inc.: Coastal Refining and
Marketing requests that you remove the \\ord "generally" iVom line 25 on pane 2 of the OU2
Proposed Plan.
Response: The ROD has been modified to remove the uord "generally" from the corresponding
text.
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ATTACHMENT I
Glossary of Terms
ARARS - Applicable or Relevant and Appropriate Requirements - Cleanup standards, standards of
control or other environmental protection requirements.
AR File - Administrative Record File - includes all pertinent documents and site information which
forms the basis and rationale for selection of a remedial alternative.
Aquifer - A saturated subsurface zone.
Carcinogen - .A compound or substance that increases the incidence of cancer.
Chronic
Exposure - A persistent, recurring, or long-term exposure. Chronic exposure may result in health
effects that are delayed in onset, occurring long after exposure has ceased.
CERCLA - Comprehensive Environmental Response. Compensation and Liability Act of 1980. The
federal "Superfund" law.
COCs - Chemicals of potential concern, chemicals that are potentially site-related and whose data
are of sufficient quality for use in a risk assessment.
EPA - United States Environmental Protection Agency - The support government agency for
the Pester Refinery Co. Site.
FS - Feasibility Study. The study used to evaluate various alternatives to clean up
contamination.
IN SITU - In place, as in treatment of contaminants in their location of occurrence without
excavation or extraction.
KDHE - Kansas Department of Health and Environment. The lead government agency for the
Pester Refinery Co. Site.
MAHs - Monocyclic Aromatic Hydrocarbons - a group of hydrocarbon compounds known for
their similar properties.
MCL - Maximum Contaminant Level - The maximum permissible level of a contaminant in
water which is delivered to any user of a public water supply system.
NPDES - National Pollutant Discharge Elimination System - a permit that sets standards for the
discharge of potentially contaminated water.
NCP - National Oil and Hazardous Substances Pollution Contingency Plan. The procedures
used to address the response powers and responsibilities created by the federal Superfund
law.
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\PL-
OU -
PAHS -
PRP-
RA-
RCRA-
RD/RA-
Rl-
ROD-
SARA-
Toxic -
VOCs-
Xational Priorities List. A list of the most contaminated sites as determined by the NCP.
Operable ( nit - A discrete area \\nhin a larger sue distinguished on the basis of some
defined criteria such as contaminant type, contaminated media, or some other identifiable
demarcation.
Polycyclic Aromatic Hydrocarbons - a group of hydrocarbon compounds
for their similar properties.
Potentially Responsible Party - The party identified by the U.S. EPA which is potentially
responsible for contamination.
Risk Assessment - Provides an evaluation of the potential threat to
and the environment in the absence of remedial action.
human health
Resource Conservation and Recovery Act of 1976 - legislation that established
cradle-to-grave accountability for hazardous wastes, from point of generation
to point of ultimate disposal.
Remedial Design/Remedial Action - The remedy phase in the CERCLA process which
involves the description and design of the remedy and the subsequent implementation of
approved plans.
Remedial Investigation - The investigative phase in the CERCLA process which
involves field investigation to determine the nature and extent of contamination at a site.
the identification of ARARs for the site, the characterization of risk posed by
contamination at a sit. and the performance of pilot treatability studies for possible
treatment remedies, as necessary.
Record of Decision - The official document by U.S. EPA which selects the remedy to
clean up a Superfund site.
Superfund Amendments and Reauthorization Act of 1986. The federal law which
amended and extended authorization of the original Superfund law (CERCLA).
A descriptor indicating harm to human health or other living organisms.
Volatile Organic Compounds - generally man-made chemicals that are found in many
household, commercial, and industrial products. They are used widely in industrial
processes. VOCs in ground water are a concern due to their potential health effects.
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