United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R07-92/061
March 1992
&EPA Superfund
Record of Decision;
Hydro-Flex, KS
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NOTICE
The appendices listed in the index that are not found in this document have been removed at the request of
the issuing agency. They contain material which supplement but adds no further applicable information to
the content of the document. All supplemental material is, however, contained in the administrative record
for this site.
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R07-92/061
3. Recipients Accession No.
4. Title and Subtitle
SUPERFUND RECORD OF DECISION
Hydro-Flex, KS
First Remedial Action - Final
5. Report Date
03/09/92
7. Author(s)
8. Performing Organization Repl No.
9. Performing Organization Name and Address
10. Project/Task/Work Unit No.
11. Contract(C)orGrant(G)No.
(G)
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report & Period Covered
800/000
14.
15. Supplementary Notes
PB93-964304
16. Abstract (Limit 200 words)
The 2.95-acre Hydro-Flex site, located in Topeka, Kansas, was used for manufacturing
flexible copper couplings. Land use in the area is primarily industrial/commercial,
with several scattered residences nearby. The site overlies a low-lying alluvial plain
south of Soldier Creek and north of the Kansas River. The alluvium, which makes up part
of the Kansas River floodplain, serves as a drinking water source for approximately
6,551 people within a 3-mile radius. From the 1970's to the 1980's, Hydro-Flex
discharged an average of 90 gallons per day of process wastewater into an onsite
wastewater disposal system consisting of a septic tank with three concrete manholes and
a soil absorption field. In 1981, the onsite wastewater disposal ceased and was
subsequently taken out of operation when Hydro-Flex was connected to the Topeka sewer
system. A PA/SI performed by the state identified sludge and ground water contaminated
with chromium and copper. This ROD addresses onsite sludge and ground water. EPA
investigations have shown that levels of chromium and copper in the soil are not above
naturally occurring levels and, therefore, no longer pose a health threat under current
(See Attached Page)
17. Document Analysis a Descriptors
Record of Decision - Hydro-Flex, KS
First Remedial Action - Final
Contaminated Media: none
Key Contaminants: none
b. Identifiers/Open-ended Terms
c. COSATI Field/Group
18. Availability Statement
19. Security Class (This Report)
None
20. Security Class (This Page)
None
21. No. of Pages
24
22. Price
(See ANSI-Z39.18)
See Instructions on Raverse
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
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EPA/ROD/R07-92/061
Hydro-Flex, KS
First Remedial Action - Final
Abstract (Continued)
or likely land use conditions. Therefore, there are no contaminants of concern affecting
this site.
The selected remedial action for this site is no further action because there is
currently no significant contamination in the sediment-free ground water, or any
significant continuing source of contamination to the ground water from the site. There
are no costs associated with this no action remedy.
PERFORMANCE STANDARDS OR GOALS: Not applicable.
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RECORD OF DECISION DECLARATION
SITE NAME AND LOCATION
Hydro-Flex Site
Topeka, Kansas
STATEMENT OF BASIS AND PURPOSE
This decision document presents the remedial actions selected for
the Hydro-Flex site in Topeka, Kansas. The final -site remedy was
selected in accordance with the Comprehensive Environmental
Response, Compensation and Liability Act of 1980 (CERCLA), as
amended by the Super fund Amendments and Reauthorization Act of 1986
(SARA) 42 U.S.C. Section 9601 et sea, and with the National Oil and
Hazardous Substances Pollutions Contingency Plan (NCP), 40 C.F.R.
Part 300. This decision is based upon the documents and
information contained in the Administrative Record for the site.
A copy of the Administrative Record is available for public review
in the U.S. Environmental Protection Agency (EPA) Region 7 Docket
Room, 726 Minnesota Avenue, in Kansas City, Kansas, and at the
Kansas Department of Health and Environment (KDHE), Bureau of
Environmental Remediation, Building 740, Forbes Field, Topeka,
Kansas.
DESCRIPTION OF THE SELECTED REMEDY
In the absence of any significant contamination in the sediment-
free groundwater, coupled with the lack of any significant
continuing source of contamination to the groundwater from the
site, the No Action alternative was selected as the preferred
alternative. Under the No Action alternative, KDHE and EPA would
take no action at the site. The site will be evaluated for
deletion from the NPL.
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RECORD OF DECISION (ROD)
HYDRO-FLEX SITE
Topeka. Kansas
Prepared by:
KANSAS DEPARTMENT OF HEALTH AND ENVIRONMENT
Bureau of Environmental Remediation
Forbes Field, Building 740
Topeka, Kansas 66620-7500
MARCH 1992
DECLARATION
The selected remedial alternative is protective of human health and
the environment. No remedial action is necessary to ensure
protection of human health and the environment.
Date y Morris/Kay
Regional Administrator
Attachment: Responsiveness Summary
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TABLE OF CONTENTS
DECLARATION
TITLE PAGE
TABLE OF CONTENTS
DECISION SUMMARY
Section 1. SITE LOCATION AND CHARACTERIZATION
1.1. Location
1.2. Area Land Use
1.3. Area Water Use
Figure 1. Site Location and Vicinity
Figure 2. Private and Public Water Use
and Land Use
Section 2. SITE HISTORY AND ENFORCEMENT ACTIONS
2.1. Waste Disposal
2.2 Initial Site Discovery and Actions
Figure 3. Site Layout and Sampling
Locations
Section 3. INVESTIGATION HISTORY
3.1 Summary of PA/SI
Table 1. PA/SI Groundwater Data
3.2 Summary of Remedial Investigation (RI)
3.2.1. Obj ectives
3.2.2. Activities
3.2.3. Results and Conclusions
Table 2. Soil/Sludge Results
Table 3. Groundwater Sample Results
Section 4. SUMMARY OF SITE RISKS
4.1. Contaminants of Concern
4.2. Exposure Assessment
4.3. Toxicity Assessment
4.4. Risk Characterization
4.5. Ecological Risks
Section 5. FEASIBILITY STUDY (FS) DETERMINATION
5.1. Feasibility Study Process
5.2. Determination
Section 6. COMMUNITY RELATIONS
Section 7. DESCRIPTION OF THE NO ACTION
ALTERNATIVE
1
1
1
1
2
3
4
4
4
5
6
6
7
7
7
7
8
9
9
11
11
11
14
15
15
16
16
16
16
17
ATTACHMENT 1. RESPONSIVENESS SUMMARY
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DECISION SUMMARY
HYDRO-FLEX SITE, TOPEKA, KANSAS
SECTION 1, SITE LOCATION AND DESCRIPTION
1.1. Site Location
The Hydro-Flex site is located in northwest Topeka, Kansas at 2101
NW Brickyard Road (see Figure 1) . The site is approximately 3.7
miles northwest of the state capitol in downtown Topeka. The full
site consists of 2.95 acres of land. There are two buildings
located on the site including the main single story building on the
northeast side of the property. Although production facilities
were formerly located in this building, the main building is
currently being used primarily for storage and office space. The
smaller building is rental property for small business (the latest
business was a small radio station).
1.2... Area Land Use
The surrounding area is primarily industrial/commercial with
several scattered private residences (refer to Figure 2) and has
unrestricted access. There are seven residences within 500 yards
of the facility. A Quaker Oats manufacturing facility is located
directly across the road from Hydro-Flex. A grain elevator
operation is located along railroad tracks approximately one
quarter mile south of Hydro-Flex. An industrial area, including
grain elevator operations is located one quarter mile to the west.
Besides the residences nearest the Hydro-Flex site, there are rural
residential neighborhoods located one quarter mile northeast and
one half mile southeast of the site. Agricultural land is
interspersed between these industrial and residential areas.
The seven residences in the vicinity of the site are older
residences that predate the industries. A zoning ordinance
prohibiting the resale of the residences for residential use is in
effect. The ordinance stipulates that the property can be sold
only for industrial purposes.
1.3. Area Water Use
The site overlies a low-lying alluvial plain south of Soldier Creek
and north of the Kansas River. Alluvial aquifer materials
underlying the site are approximately 75 feet in depth and consist
of clay, silt, sand, and gravel deposits; and depth to groundwater
is approximately 21 feet. The alluvial aquifer overlies shale,
limestone, or sandstone bedrock. The sand and gravel layers are
capable of providing maximum groundwater yields of 2,000 gallons
per minute,.
The alluvium which makes up part of the Kansas River flood plain
is a major source of groundwater in the area and serves domestic
and municipal (Rural Water District #4) usages. Two public supply
wells (RWD #4) are within a 2-mile radius of the site and are 75
to 85 feet deep. Approximately 13, 41, and 64 domestic wells are
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HYDRO-FLEX SITE
.1 * „
nil _••_ • au .p
J V, J ^aS^S^?^
1000 2000 3000 4000 5000 6000 7000 FECT
KANSAS
QUADRANGLE LOCATION
FIGURE 1: SITE LOCATION AND VICINITY MAP
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auo •
RURAL WATER DIST.
#4 WELL
^ *• • i
(monitoring well)
.v
FIGURE 2. PRIVATE AND PUBLIC WATER USE
AND LAND USE
!\rCITY OF TOPEKA
SURFACE WATER INTAKE
KEY
Residential EH—
Industrial
Domestic well -
1 inc 1056 feet
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within the 1-, 2-, and 3-mile radii, respectively. There are an
estimated 6,312 persons served by Rural Hater District #4 wells and
an estimated 239 persons served by domestic wells within a 3-mile
radius.
The City of Topeka Water Department, which utilizes two concrete
surface water intake structures along the Kansas River, services
44,938 meters, numerous rural water districts, and three major
Topeka industries. These intakes are located approximately 6,200
feet to the southeast of Hydro-Flex (see Figure 2).
SECTION 2, SITE HISTORY AND ENFORCEMENT ACTIVITIES
2.1. Waste Disposal
Hydro-Flex acquired the property at 2101 N.W. Brickyard Road in the
Fall of 1970. The facility was constructed during the winter of
1970-1971 and placed in operation during March 1971. Because it
was not possible to obtain a sewer connection at that time, Hydro-
Flex was allowed to utilize an on-site wastewater disposal system
consisting of a septic tank in series with three concrete manholes
and a soil absorption field.
During the 1970s and into the 1980s, Hydro-Flex manufactured
flexible copper couplings. Process wastewater was generated in
batches that were intermittently discharged in amounts averaging
90 gallons/day. The characteristic concentrations of chromium and
copper in the combined process and sanitary wastewater system are
estimated to have been 122,000 and 107,000 micrograms per liter
(ug/1), respectively.
Due to capacity limitations, the Hydro-Flex wastewater system was
reportedly unable to accept the process wastewater during certain
periods. A reported one-time attempt was made to dispose of waste
into an on-site industrial well (designated HF-4) . In July 1981,
Hydro-Flex was connected to the Topeka sewer system. On-site
wastewater disposal ceased at this time. KDHE then approved Hydro-
Flex's request to take the on-site system out of operation by
filling the manholes with sand and covering the area with soil.
2.2. Initial Site Discovery and Actions
The Kansas Department of Health and Environment (KDHE) completed
a Preliminary Assessment/site Investigation (PA/SI) for the site
during March 1987. KDHE constructed three monitoring wells at the
site, acquired water and sludge samples from the industrial well
(HF-4) present at the site, and obtained groundwater samples from
the newly constructed wells and five nearby private wells (see
Figures 2 and 3) . The investigation indicated that onsite
groundwater was contaminated with chromium and copper (see Table
1) and that further investigation to determine the extent of
contamination was necessary. Subsequently, the site was nominated
by the U.S. Environmental Protection Agency (EPA) for the National
Priorities List (NPL) . The NPL is EPA's list of the most serious
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Perforated
Underground Pipe
Sample Bodny/SompU
location
IUMHOLC TO TOPEXA
SCVCR SYSTEM
FIGURE 3: SITE LAYOUT AND SAMPLING LOCATION
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hazardous waste sites identified by means of a standardized scoring
system.
on March 30, 1989, the Hydro-Flex site was added by EPA to the NPL.
Following the site listing, a Consent Agreement was signed between
the KDHE and Hydro-Flex Corporation for Hydro-Flex to conduct a
Remedial Investigation/Feasibility Study (RI/FS) . The Workplan for
the RI/FS activities was approved by KDHE on January 10, 1990 and
work commenced at the site during September 1990. Additional RI
site work was initiated during the early Spring of 1991. The Final
RI report was approved in September of 1991. Subsequent to the
results of the Baseline Risk Assessment contained i'n the RI report
and supplemental evaluation of the site data, KDHE and EPA
determined that a Feasibility Study (FS) was not required for the
site.
SECTION 3, INVESTIGATION HISTORY
3.1 Summary of PA/SI
Three monitoring wells were constructed for the preliminary
investigation of the site (see Figures 2 and 3) . HF-1 was
constructed to a depth of 45 feet with a ten foot screen at the
bottom (sand aquifer) and was intended for use as a background
well. HF-2 was constructed to a depth of 35 feet with a ten foot
screen at the bottom (sand aquifer). HF-3 was constructed to a
depth of 75 feet (to shale bedrock) with a ten foot screen at the
bottom (sand and gravel aquifer). HF-4 was installed by Hydro-Flex
in the early 1970's and served as an industrial process water well
for a short time. There are no construction records available for
this well although the depth is approximately 70 feet according to
field measurements. Screens for production wells are commonly
placed at multiple levels in the alluvial aquifer.
Due to the sludge and debris (reportedly broom straw and other
unidentifiable small pieces of trash) present in the bottom portion
of HF-4, it was possible to separate the different substances and
to collect both water and sludge samples from this well. The
results of the groundwater samples (see Table 1) indicated that
both unfiltered water and sludge from HF-4 were highly contaminated
with chromium and copper. An unf iltered sample taken from HF-3 was
found to have levels of chromium above the State and federal
drinking water standard. Sludge contained in HF-4 was not found
to be hazardous (EP-TOX less than 5 mg/1). EP-TOX is a laboratory
measurement of the leaching character and in-turn the toxicity of
solid materials. Groundwater flow was found to be in an east-to-
southeasterly direction according to January 1987 water level
measurements.
Samples were taken and analyzed by KDHE from four privately owned
domestic use wells during June, 1988 (locations 1W, 2W, 3W, and 4W
denoted on Figure 2). The results of these samples indicated
chromium levels below detection limits and-copper levels between
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non-detectable levels and 720 ug/1. These values meet state and
federal drinking water standards and do not reflect contaminant
levels of public health concern.
TABLE 1
January 1987
(unfiltered)
chromium
copper
EP-TOX chromium
(filtered)
chromium
copper
PA/SI GROUNDWATER DATA*
HF-1 HF-2 HF-3
HF-4
sludge
20.0
50.0
-
ND
50.0
-
290.0
370
—
483980.0
526500
—
36531000
47061000
0.2
ND
20
ND
40
ND
60
530
450
* Concentrations are in ug/1, except for EP-TOX which is in
milligrams per liter (mg/1); ND means "not detected".
3.2.1. Ob"i ectives
The objectives of the RI included: (1) the definition of the nature
and extent of contamination in groundwater; (2) the definition of
the nature and extent of contamination in the soil; (3) the
identification of any possible sources of contamination; (4) the
characterization of the site geohydrology; and (5) evaluation of
the site's existing and potential threat to human health and the
environment.
3.2.2. Activities
The RI activities consisted of the construction of two additional
monitoring wells and the sampling and analyses of soil, sludge, and
groundwater (refer to Figure 3). Soil borings were collected from
the centers of the three manholes for the purpose of determining
whether or not sludge or soil contamination was present, and, to
determine if manhole bottoms were intact. A total of 11 soil core
borings were performed at other locations adjacent to the manholes
and throughout the septic system in order to determine the presence
of contamination in soils due to the wastewater disposal
activities. Soil and aquifer material samples were taken for
analysis of grain size distribution, pH, and organic matter. A
series of six groundwater elevation measurements were taken at the
monitoring wells over a period of a little over one year.
The installation of monitoring wells HF-5 (depth of 75 feet, 9 foot
screen) and HF-6 (depth of 39 feet, 9 foot screen) was completed
to gather information to determine whether contaminants had
migrated from the industrial well (HF-4) where a one-time disposal
of process waste had occurred. The screened interval in well
HF-4 is unknown although it was presumed on the basis of the
construction of other wells in the area, that the lower permeable
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sand and gravel material was screened at an estimated 60 to 70 feet
and that the upper sandy material was probably screened at an
estimated 30 to 40 feet. HF-5 was constructed in the lower zone
to detect contamination from the one-time introduction of process
water into well HF-4. HF-6 was constructed in the upper zone to
detect any downgradient contamination from the septic field
disposal area and the upper zone of HF-4. Groundwater samples were
taken during May of 1991 from all 5 monitoring wells (HF-l, HF-2,
HF-3, HF-5, HF-6) and the industrial water supply well (HF-4) for
analyses of heavy metals. Samples from all 5 monitoring wells were
taken for analyses of volatile organic compounds and base-neutral
acid compounds.
The field work for the RI was conducted over a period of 8 months.
Samples from MH-1, MH-2, and the soil boring adjacent to MH-1 were
collected during October, 1990. The remaining soil and manhole
samples were collected during March, 1991. Wells HF-5 and HF-6
were constructed and developed during March, 1991. Well HF-4 was
further purged of sludge and debris and sampled during March, 1991.
All site monitoring wells were sampled during May, 1991.
During the community relations interviews conducted by KDHE in
March of 1991, two residents south of the Hydro-Flex site requested
that their well water be tested for heavy metals (see sampling
locations 1W and 5W on Figure 2). KDHE sampled the wells during
May 1991.
3.2.3. Results and Conclusions
Manhole Soil and Sludge Samples
Two of the manholes (MH-l and MH-2) were found to have intact
bottoms, although the structural integrity of the bottoms of the
manholes could not be established. MH-3 did not have an intact
bottom and showed the presence of naturally occurring very fine
alluvial sand underlying a thin sludge layer. Chromium and copper
contaminated sludge is present at the bottom of MH-1 and MH-3
(refer to Table 2). Analytical data from MH-2 indicated increasing
chromium (278 milligrams per killigram (mg/kg)) and copper (209
mg/kg) levels to a depth of 17 feet which is the bottom of the
manhole. The strata containing sludge in MH-1 consisted of a 1
foot thick layer of wet, grayish brown clay with moderate blue-
green streaks throughout. The average concentrations of chromium
and copper in samples taken from this zone are 14,800 and 20,000
mg/kg respectively. The sludge layer in MH-3 is approximately 0.1
foot in thickness. The average chromium and copper concentrations
from samples taken in this layer are 2,650 and 3,950 mg/kg
respectively.
Sludge samples having chromium or copper levels greater than 100
mg/kg were analyzed for leachable chromium (using the EP-TOX
procedure as specified in the RI/FS Workplan) to determine if the
levels were hazardous (EP-TOX greater than or equal to 5 mg/1),
when a sufficient amount of sample material was available. The
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TABLE 2. SOIL/SLUDGE RESULTS
May 1991
Depth MH-1 MH-2 MH-3 HF-4-S
Surface
5
Chromium
Copper
Feet
Chromium
Copper
8.49
7.42
209
296
58.9
64.9
86.3
192
32.9
38.8
40.1
40.0
-
—
-
—
Bottom
Chromium
EP-TOX
Copper
16,000
0.33
23,000
278
0.25
3.67
4,440
2.40
6,880
56,200
44.0
102,000
* Notes for Table 1:
1. Concentrations in mg/kg, except EP-TOX results reported
in mg/L.
2. HF-4-S denotes sludge taken from well HF-4 (not a
groundwater sample).
3. Dash indicates sample not taken.
TABLE 3. GROUNDWATER SAMPLE RESULTS, Hay 1991
Parameter HF-1 HF-2 HF-3 HF-4 HF-5 HF-6
Chromium
Copper
Fill.
4
14
Tot.
52
62
Filt.
7
12
Tot.
115
75
Filt.
3
5
Tot,
26
83
Filt.
3
14
Tot.
14
38
Filt.
4
5
Tot;.
360
171
Filt. Tot.
6 55
16 109
• Notes for Table 2 :
1. Concentrations in ug/L.
2. Ftlt. and Tot. denote filtered and unfiltered samples respectively.
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results for the samples from the manholes are shown in Table 2.
Hexavalent chromium levels in two MH-1 samples were not detectable.
Soil Boring Samples
The 27 soil samples (from the 11 soil borings) which were analyzed
showed concentrations of copper and chromium less than 100 mg/kg,
comparable to expected background levels (as determined from
available literature) with no indication of any significant
contamination. Mean chromium and copper concentrations were
calculated to be 14.0 and 12.7 mg/kg; and maximum values reported
for these elements were 76.4 and 47.8 mg/kg, respectively.
Well HF-4
Sludge and debris were bailed from HF-4 during the initial PA/SI
investigation in 1986 and again during the RI in March and May of
1991. Chromium and copper concentrations reported in the samples
taken during January 1987 were from 36,531,000 to 47,061,000 ug/1
and those taken in March 1991 were from 5,800 to 7,500 mg/kg in
unfiltered samples containing sludge. EP-TOX for chromium was 0.2
mg/1 for the January 1987 sample and 44 mg/1 for the March 1991
sludge sample from HF-4. Filtered samples taken from HF-4 during
the May 1991 sampling indicated chromium to be less than the
detection limit and total chromium (unfiltered) was less than the
Kansas Action Level (KAL) of 50 ug/1 (see Table 2). Filtered and
unfiltered groundwater samples analyzed for copper were below the
1,000 ug/1 KAL for copper. The low levels of chromium and copper
in the unfiltered and filtered samples, the lack of debris or
sludge in the sample and purge water, and the clarity of the sample
from the May 1991 groundwater samples seem to indicate that the
sludge and debris were removed from HF-4 during the sampling in
January, 1987 and March, 1991.
Groundwater Samples
The analytical results for groundwater samples are at naturally
occurring background levels based on evaluation, or give no
indication of significant contamination, except for the unfiltered
sample taken from HF-5 (chromium = 360 ug/1) (see Table 3).
Unfiltered groundwater sample concentrations for chromium exceeded
the maximum contaminant level (MCL) of 100 ug/1 in two monitoring
wells and exceeded the KAL in four monitoring wells including the
background well (HF-1) located approximately 800 feet north of the
site. Therefore, it was concluded that naturally occurring
suspended solids in the aquifer were present at levels high enough
to exceed the KAL and the MCL in at least one instance. None of
the filtered groundwater samples exceeded the KAL or MCL for
chromium. Contamination from volatile organic compounds or base
neutral compounds was not observed in soil or groundwater samples.
The sample results from the two private wells (1W and 5W on Figure
2) sampled by KDHE showed chromium concentrations of 4 and 6 ug/1
and copper concentrations of 11 and 45 ug/1. Volatile organic
10
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compounds were not detected. These levels of copper and chromium
meet the drinking water standards and are therefore not indicative
of a health concern.
Groundwater Flow
A series of groundwater elevation measurements taken at the site
monitoring wells from March 1990 through May 1991 indicated that
groundwater flow at the site was in a northeasterly direction.
Since the site is located in alluvial materials between the Kansas
River and Soldier Creek, the direction of groundwater flow is
subject to fluctuations affected by the river and creek stage
levels.
SECTION 4, SUMMARY OF SITE RISKS
As part of the RI, a baseline Risk Assessment for the Hydro-Flex
site was prepared. The risk assessment was carried out to
characterize the current and potential threats to human health and
the environment that may be posed by contaminants migrating in
groundwater, released to the air, leaching through the soil, or
remaining in the soil. The findings of the baseline Risk
Assessment and supplemental evaluation of the site data concluded
that no risks to human health or the environment were found at the
site.
4.1. Contaminants of Concern. Chromium and copper are the
chemicals of concern at the Hydro-Flex site based on past site
disposal practices, concentrations detected at the site, toxicity,
and physical/chemical properties that affect transport and
persistence in air, soil and groundwater.
4.2. Exposure Assessment
4.2.1. Exposure Pathways
The environmental pathways of contaminant transport evaluated at
this site are groundwater, surface soil, surface water runoff, and
atmospheric dispersion.
The major area of wastewater disposal occurred in the three
manholes. The area occupied by each manhole is estimated to be no
more than 13 square feet. The manholes were filled with sand and
covered with soil in 1981. Therefore, direct exposure to
contaminated soil or sludge in the manholes is not expected to
occur, barring potential future excavation in these areas of the
site.
Atmospheric dispersion of soil is not expected to be significant.
No contamination of surficial material at this site was found.
Surface soil samples analyzed from the soil borings indicated
levels less than 100 mg/kg. The chromium and copper in the soil
on site are not above naturally occuring levels.
11
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Hydro-Flex is located in a relatively flat floodplain with little
topographic variation. Any accumulation of surface water from
precipitation is expected to be absorbed into the ground. . There
were no surface water drainage patterns observed at the site. No
contaminant sources were identified at the site surface.
Therefore, surface water is not expected to provide a pathway for
exposure to contaminants.
4.2.2. Sources of Contamination
The contamination that remains on site is highly localized within
three .small areas: (1) a small amount of sludge present in MH-1,
(2) a small amount of sludge present in MH-3, and (3) a small
volume of water (estimated according to geohydrological and
contaminant characteristics) in the vicinity of and immediately
downgradient from the screen of HF-4 (see sample results of HF-5,
Table 3).
4.2.3. Contaminant Transport
Transport, through the vadose zone to the groundwater table, of
chromium and copper in the sludge at the bottom of the manholes is
minimal since these contaminants were found to be tightly adsorbed
within the surrounding clay matrix. Analysis of soil below sludge
in MH-3 and in soil borings adjacent to the manholes did not
indicate any contamination. Further, EP-TOX chromium measurements
for the sludge samples (March 1991) were less than the hazardous
criterion of 5 mg/1.
Although hexavalent chromium was originally present in wastewater
at the site, it was most likely converted to its trivalent form due
to the soil environment where it was disposed. In deeper soil
where anaerobic conditions exist, hexavalent chromium will be
reduced to trivalent chromium by sulfur and iron ions present in
soil. The reduction of hexavalent chromium to trivalent chromium
also occurs in aerobic soils that contain organic energy sources.
One sample, and a duplicate, were analyzed for hexavalent chromium
with non-detectable results. The high levels of total chromium
found in the sludge layers and the corresponding low EP-TOX results
are also strongly indicative that hexavalent chromium has been
converted to trivalent chromium at the site.
Trivalent chromium is strongly adsorbed to soil components and
consequently is much less mobile than hexavalent chromium. The
trivalent form tends to be adsorbed strongly onto clay particles
and organic particulate matter, but can be mobilized if it is
complexed with organic molecules.
Transport, via the groundwater, of contaminants which were disposed
in well HF-4 is the major transport mechanism at the site.
Contaminants, in the form of suspended sediments in the groundwater
have migrated at least 6 feet to the east, of well HF-4. Future
transport is dependent on the groundwater flow velocity and
12
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direction, and the physical and chemical properties of the
contaminants and the aquifer materials.
The current estimated extent of groundwater contamination and
future predictions based on site geohydrological information,
indicate that the transport of contaminants is, and will continue
to be minimal in the future. This small area of contamination is
limited to the site location and is not expected to migrate off-
site. Over a long-term period dilution, dispersion, and adsorption
processes will lower the contaminant levels.
4.2.4. Conclusions
Although contamination by chromium in the groundwater in the
vicinity of HF-4 has migrated at least 6 feet to the east, the
contamination is nearly completely associated with suspended solids
as indicated in a comparison of the filtered and unfiltered
samples. Exposure via ingestion, to the levels of chromium found
in the unfiltered groundwater samples would be highly unlikely for
the following reasons: (1) the high turbidity of the groundwater
from the monitoring wells would not generally occur in properly
developed and constructed water supply wells; and (2) the high
turbidity of the groundwater from the monitoring well samples (143-
2,080 NTU-a unit to measure the loss of clarity in water) is
greater than the maximum contaminant level (MCL) for turbidity and
would not be acceptable for drinking water on this basis. The MCL
is a federal drinking water standard set for public water supplies.
Copper was also found to be associated with suspended solids in the
groundwater at what appear to be natural background levels.
There is currently no groundwater usage at the site. The five
private wells located in the immediate vicinity of the Hydro-Flex
site (located south and north of the site) are not and would not
be affected in the future by this small amount of contamination
according to predictions based on the aquifer and contaminant
characteristics. These domestic wells, serving an estimated 19
persons, would be the potential receptors of groundwater
contamination. Sampling and analyses of unfiltered private well
samples from three of these wells, conducted by KDHE subsequent to
the original PA/SI in June of 1988 and in May 1991 gave no
indication of contamination by chromium or copper.
Groundwater flow direction is variable in the site area due to
river fluctuations. The water level measurements over the past
year have indicated groundwater to be flowing toward the northeast.
The closest downgradient receptors for this flow would be private
wells located approximately 1/2 mile to the northeast. These
wells, and private wells located in a neighborhood approximately
1/2 mile east of the site would appear to be at no risk.
Domestic well users in the area would not be expected to be exposed
to contaminated groundwater in the future due to the low amount of
contamination, small amount of migration, and groundwater
attenuation mechanisms. It is unlikely that the site would be
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converted to residential property in the future due to the City
ordinance concerning transfer of property for other than industrial
use and the current industrial use at the site. If a private well
were constructed in the immediate area of HF-4 and HF-5 in the
immediate future, suspended solids present in the groundwater
around the well would probably exceed the allowable limits for
drinking water. However, if the well were constructed and
developed properly to eliminate sediment from the well water (to
comply with turbidity levels within the drinking water standard)
contamination would be eliminated with the sediment.
Well HF-4, originally constructed as a production well, and the
source of contamination due to the dumping of process waste, has
been purged and developed by Hydro-Flex. The latest samples taken
from HFr4 showed a chromium level of 14 ug/1 (complies with
drinking water standards) for the unfaltered sample. The HF-4 well
now exhibits drinking water quality water.
City water is currently being used at the site. There is no reason
to believe that future use would involve an industrial production
well. However, if HF-4 or a newly constructed site well were to
be used as an industrial production well, it is unlikely that
industrial requirements would allow the water to contain a high
level of suspended solids (and in-turn contaminants). After HF-4
was properly developed, a high level of clarity was achieved in the
unfiltered sample. High-capacity industrial wells in the immediate
area of the site might affect groundwater flow enough to pull
contamination in the area of HF-4 and HF-5 toward the area of the
producing industrial well. The affected contaminant slug would
undergo dilution, dispersion, and adsorption of the groundwater
contaminants. The estimated small volume of suspended solids
contamination in the groundwater is not expected to pose a
significant added risk in the case of a high-capacity well
scenario.
Direct exposure due to possible future excavation of the sludge and
surrounding soil in MH-1 and MH-3 is possible. However, it is
highly unlikely that exposure to this contamination would occur
accidentally. In the case of excavation of the entire manholes or
the contents of the manholes, the greenish, bluish dis-coloration
of the sludge layers could easily be discerned and handled
accordingly to avoid direct exposure.
4.3. Toxicitv Assessment
The contaminated and potentially contaminated media identified
above could lead to the following theoretical human exposures:
ingestion of contaminated groundwater and soil, dermal contact with
contaminated soil, and inhalation of atmospherically entrained
dust. However, the only human exposure pathway of concern was
found to be ingestion of contaminated groundwater.
Chromium is a toxic pollutant which, when ingested at sufficiently
high doses, can cause adverse human health effects. The toxicity
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of chromium depends on its chemical form. At least small doses of
trivalent chromium are considered necessary for human nutrition.
Hexavalent chromium is more toxic than the trivalent form, and when
exposure is via the inhalation route, is considered a known human
carcinogen. However, there is no evidence at the current time that
hexavalent chromium is carcinogenic when orally ingested.
The National Research Council has estimated that an adequate and
safe daily dietary intake range for trivalent chromium is 50 to 200
ug/1. The Kansas Action Level (KAL) established for chromium in
drinking water is 50 ug/1. The EPA recently lowered the national
primary drinking water standard or maximum contaminant level (MCL)
for total chromium to 100 ug/1.
The KAL for copper in drinking water is 1000 ug/1. The EPA health
advisory of 1300 ug/1 for copper is based primarily on taste and
odor properties rather than adverse health effects, although
groundwater containing levels of copper above the health advisory
used over a long period might precipitate adverse health effects.
However, there are no reports of adverse health effects due to
copper ingestion at high levels, probably because the taste
imparted to water by copper at 1000 to 2000 ug/1 prevents chronic
ingestion.
Reference doses (RfD) for oral noncarcinogenic effects have been
established by EPA for hexavalent and trivalent chromium. The RfD
is a level of exposure, based on the available toxicological data,
below which it is believed to be unlikely that even sensitive
populations will experience adverse health effects. The RfD for
ingested trivalent chromium is 1 mg/kg per day in drinking water
with assumed 1.0 gastro-intestinal tract absorption fraction. The
RfD for ingested hexavalent chromium is .005 mg/kg per day in
drinking water.
4.4. Risk Characterization.
The effects of risks, toxicity, and exposure were integrated into
quantitative and qualitative expressions. Exposure to trivalent
and hexavalent chromium levels for both dissolved and total
(unfiltered) groundwater at the site yield a hazard index of less
than one which is the effect threshold for risk to human health.
The standard exposure assumptions were used to calculate the hazard
index. Therefore, the noncarcinogenic risk from possible ingestion
of groundwater present at the site is zero. Since inhalation of
chromium (hexavalent or trivalent) is not considered an exposure
pathway at the site, the carcinogenic risk would also be zero.
4.5. 'Ecological Risks. The ecological effects due to
contamination found at the Hydro-Flex site are considered
insignificant for the following reasons: (1) the sampling data for
surface soils indicates that levels of copper and chromium are
present at what was determined to be naturally occuring background
levels; (2) the low levels of contamination found in groundwater
on-site are not expected to affect any ecological environments now
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or in the future; (3) the small amounts of chromium and copper
contamination found in soils at depths of approximately 15 feet
(bottoms of MH-1 and MH-3) are not expected to leach into the
groundwater or to pose a threat to ecological environments, (4)
there are no wetlands or other sensitive ecosystems in the site
area, (5) there are no endangered species which might be affected
by contamination at the site.
SECTION 5, FEASIBILITY STUDY DETERMINATION
5.1. Feasibility Study Process
The purpose of the FS is to identify technology and/or process
options that can be developed into an appropriate range of remedial
alternatives assuring protection of human health and the
environment. The range of appropriate remedial alternatives
depends on site-specific remedial action objectives, based on
compliance with applicable or relevant and appropriate requirements
(ARARs).
The development of alternatives in the FS process generally occurs
in three phases: identification and development of technology
process options; development and preliminary screening of
alternatives assembled from technology process options; and
detailed analysis of alternatives. In the FS, selected
alternatives are evaluated and compared to nine criteria required
by the National Contingency Plan (NCP).
5.2. Determination
KDHE and EPA have determined that an FS is not necessary for the
Hydro-Flex site. The rationale for over-riding the usual
requirement that an FS be performed for NPL sites is based on the
following rationale:
1. The baseline Risk Assessment and supplementary evaluation
based on the site data conclude that there are no risks to
human health or the environment due to contamination found at
the site. Information presented in the Risk Assessment
indicates that unacceptable exposures to hazardous substances
will not occur.
2. The lack of significant complexity at the site
substantiates the determination that the detailed screening
and analysis process required for the FS is not necessary.
SECTION 6, COMMUNITY RELATIONS
The KDHE, by providing a Proposed Plan and the supporting documents
in the Administrative Record, encouraged public review and comment
on the preferred alternative. The community was given an
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opportunity to submit written or oral comments during a public
comment period held from December 21, 1991 to January 21, 1992.
A public meeting was held in Topeka during the public comment
period, to present the Proposed Plan, answer questions, and receive
oral and written comments.
The Proposed Plan was available for public review at the KDHE
offices at Building 740, Forbes Field, Topeka (8:00-4:30 Monday
through Friday except holidays) ; at the Topeka Public Library, 1515
SW 10th Street, Topeka; and at the EPA Region VII Offices, 726
Minnesota Avenue, Kansas City, Kansas.
The KDHE has prepared an Administrative Record File for the site
which contains all documents and records on which decisions about
the site were based. The Administrative Record File is available
at the KDHE office and at the EPA Region VII Office.
No written comments were received on the Proposed Plan.
SECTION 7, DESCRIPTION OF THE NO ACTION ALTERNATIVE
In the absence of any significant contamination in the sediment-
free groundwater, coupled with the lack of any significant
continuing source of contamination to the groundwater from the
site, the No Action alternative was selected as the preferred
alternative. Under the No Action alternative, KDHE and EPA would
take no action at the site. The site will be evaluated for
deletion from the NPL.
The KDHE and EPA have identified the No Action alternative as the
preferred alternative based on the following criteria:
7.1 Protection of Human Health and the Environment
This criterion addresses whether or not a remedy provides adequate
protection of human health and the environment and describes how
risks are eliminated, reduced or controlled through waste
treatment, engineering controls, or institutional controls. In the
absence of any current groundwater at risk of further significant
contamination, and with an absence of any continuing source of
contamination in the soil or groundwater, human health and the
environment would be effectively protected by the No Action
alternative. No human health or environmental risks related to the
release of contaminants at this site were identified in the
baseline risk assessment.
7.2. State/EPA Acceptance
This criterion addresses the State and EPA preferences or concerns
about the site alternatives. KDHE has been the lead agency on this
site since 1987 and has coordinated management of this site with
EPA. The State and EPA concur with the recommended final site
remedy.
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7.3. Community Acceptance
This criterion reflects KDHE's perception of the community's
preferences or concerns about the site alternatives. The degree
of community acceptance of the preferred alternative was assessed
by KDHE and EPA. No comments were received during the public
comment period on the Proposed Plan. KDHE and EPA believe the
community supports the selected no action alternative due to the
fact that no comments or questions were received during the public
comment period (see Attachment 1) .
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ATTACHMENT 1
RESPONSIVENESS SUMMARY
HYDRO-FLEX SITE
TOPEKA, KANSAS
FEBRUARY 1992
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HYDRO-FLEX SITE
RESPONSIVENESS SUMMARY
A. OVERVIEW
The Hydro-Flex site is located in northwest Topeka, Kansas at 2101
NW Brickyard Road. The site is approximately 3.7 miles northwest
of the state capitol in downtown Topeka. During the 1970s and into
the 1980s, Hydro-Flex manufactured flexible copper couplings.
Hydro-Flex utilized an on-site wastewater disposal system
consisting of a septic tank in series with three concrete manholes
and a soil adsorption field from 1970 to 1981. A reported one-time
attempt was made to dispose of waste into an on-site industrial
well (designated HF-4).
Hydro-Flex, under a consent agreement with the Kansas Department
of Health and Environment (KDHE), conducted a Remedial
Investigation (RI) in order to determine the nature and extent of
contamination, and the potential risk to human health and the
environment. Due to the limited amounts and levels of soil and
groundwater contaminated with chromium and copper, the possibility
of transport of or exposure to chromium or copper is minimal.
In the Proposed Plan which was released to the public, the
preferred alternative for the Hydro-Flex Site was to take no
action.
B. BACKGROUND ON COMMUNITY INVOLVEMENT
Community relations activities for the Hydro-Flex Site were
initiated by KDHE in 1987. KDHE and Environmental Protection
Agency (EPA) announced the addition of the Hydro-Flex site to the
National Priorities List in 1987. KDHE conducted community
interviews in early 1991 prior to RI field work. A Community
Relations Plan was completed for the Hydro-Flex site in May of
1991.
A thirty day public comment period began on December 21, 1991 and
ended on January 21, 1992. KDHE held a public meeting on January
7, 1992 to present the preferred alternative, accept comments, and
answer questions regarding the Proposed Plan. The Responsiveness
Summary addresses the fact that no comments were received during
this period.
C. SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD
No written or oral comments were received during the public comment
period. No questions or comments were posed during the public
meeting on January 7, 1992.
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