United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R07-89/030
September 1989
Superfund
Record of Decision
Cherokee County, KS
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R07-89/030
3. Recipient1 a Acceuion No.
4. Tltte and Subtitle
SUPERFUND RECORD OF DECISION
Cherokee County, KS
Second Remedial Action
S. Report Date
09/18/89
7. Author(e)
8. Performing Organization Repc No.
9 Performing Organization Nun* and Addreee
10. Pro|ecVTe*k/Work Unit No.
11. Contntct(C) or Grant(G) No
(C)
(G)
12. Sponsoring Organization Main* and Addreee
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type o< Rtport & Period Covered
800/000
14.
15. Supplementary Note*
18. Abetract (Umte 200 word*) ' '.','<
The Cherokee County site is a lead and zinc mining area in the southeastern corner of
Kansas. The 25 square-mile Galena subsite is one of six subsites within the Cherokee
County site and consists of large areas covered by mine wastes, water-filled subsidence
craters, and open mine shafts. Many of the shafts are direct conduits to the shallow
ground water aquifer which is the sole source of drinking water for approximately 1,050
persons residing outside of the Galena city limits. The approximately 3,500 Galena
residents receive their water supply from two deep aquifer wells. EPA began
investigations of the Galena subsite in 1985 and determined that the shallow ground
water aquifer and surface water were contaminated with elevated concentrations of
metals. EPA Region VII responded by installing water treatment units on several private
wells. The first operable unit for this site was signed in 1987 and provided for the
pumping of water from existing deep aquifer wells and subsequent distribution of the
water to affected local residents through a pipeline network. This Record of Decision
represents the second of two operable units and addresses the threat of contamination to
the shallow ground water aquifer and surface water. The primary contaminants of concern
affecting the ground water and surface water are metals including cadmium, lead, and
zinc.
KS
17. Document Analytic a. Descriptor*
Record of Decision - Cherokee County,
Second Remedial Action
Contaminated Media: gw, sw
Key Contaminants: metals (cadmium, chromium, lead, zinc)
idTi
c. COSAT1 FMd/Group
18. AvritabUHy
It. Security <3»e*(Thle Report)
None
20. Security d***(TNe Peg*)
None
21. No. ol Page*
121
22. Me*
(See ANSI-ZU.1*)
OPTIONAL FORM 272 (4-77)
(Formerly NT1S-35)
Department of Commerce
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EPA/ROD/R07-89/030
Cherokee County, KS
16. Abstract (Continued)
The selected remedial action for this site includes the removal, consolidation, and
onsite placement in mine pits, shafts, and subsidences of surface mine wastes; diversion
and channelization of surface streams with recontouring and vegetation of land surface;
and investigation of deep aquifer well quality followed by plugging all abandoned and
inactive wells and rehabilitating active wells, if necessary. The estimated present
worth cost for this remedial action is $8,295,215, which includes an annual O&M cost of
$14,963.
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CHEROKEE COUNTY
GALENA SUBSITE
RECORD OF DECISION
GROUND WATER/SURFACE WATER
OPERABLE UNIT
SEPTEMBER 18, 1989
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TABLE OF CONTENTS
PAGE
DECLARATION 1
1.0 Introduction 3
2.0 Site Location and Description 4
3.0 Site History 5
4.0 Enforcement Activities 7
5.0 Community Relations History 7
6.0 Scope and Role of Operable Unit 8
7.0 Site Characteristics and Site Risks 9
8.0 Post 1988 OUFS Studies 10
9.0 Development of Alternatives 12
10.0 Description of Alternatives 15
11.0 Development and Detailed Evaluation of
the Selected Remedy 19
12.0 Summary of the Comparable Analysis
of Alternatives 33
13.0 Selected Remedy 36
14.0 Statutory Determinations 40
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RECORD OF DECISION DECLARATION
OPERABLE UNIT REMEDIAL ALTERNATIVE SELECTION
SITE NAME AND LOCATION
Cherokee County Site - Galena Subsite
Cherokee County, Kansas
STATEMENT O£ BASIS AND PURPOSE
This decision document presents the selected remedial action
for the ground water/surface water operable unit for the Cherokee
County site - Galena subsite in Cherokee County, Kansas,
developed in accordance with the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980 (CERCLA), as
amended by the Superfund Amendments and Reauthorization Act of
1986 (SARA), and to the extent practicable, the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP). This
decision is based on the administrative record for this site.
The attached index identifies the items which comprise the
administrative record upon which the selection of the remedial
action is based.
The State of Kansas has concurred on the selected remedy.
A letter from the State of Kansas stating their concurrence is
included in this Record of Decision package.
DESCRIPTION O£ THE SELECTED REMEDY
The Galena subsite is one of six subsites in the Cherokee
County site. The Galena subsite is divided into two operable
units, alternative water supply and ground water/surface water
remediation. The alternative water supply operable unit decision
document was completed in December 1987. This Record of Decision
addresses the ground water/surface water operable unit. The
function of this operable unit is to reduce the risks associated
with exposure to the contaminants at the Galena subsite. The
improvements to the ground water and surface water quality at
this subsite will be consistent with overall remediation of the
Cherokee County site. The selected remedial action for this
operable unit will also reduce the human exposure to the
contaminants in the surface mine wastes; will reduce the metals
contamination in the ground water and surface water; and will be
protective of the Roubidoux aquifer.
The selected remedy consists of the following four major
components:
- Removal and selective placement of the surface mine
wastes
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1.0 INTRODUCTION
The purpose of this document is to describe the remedial
action selected by the U.S. Environmental Protection Agency (EPA)
for implementation at the Galena subsite of the Cherokee County
site, Cherokee County, Kansas. This document also describes the
decision-making procedures that were followed in selecting this
remedial action.
The selected remedial action will remediate environmental
problems affecting the public health and the environment at the
Galena subsite. This action is one part of a response action for
remediating a site containing hazardous substances. This action
is referred to as an "operable unit" remedial action and will be
consistent with the final remedy for the site. This operable
unit remedial action is selected in accordance with the
Comprehensive Environmental Response, Compensation, and Liability
Act of 1980 (CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA), 42 U.S.C Section 9601, et
seq.
The decision-making processes regarding the Cherokee County
site began with preliminary investigations, which led to the
inclusion of the site on the National Priorities List (NPL),
making the site eligible for use of Superfund monies for cleanup
of the releases and threatened releases of hazardous substances
at the site. Based on the large size of the site and general
locations of mining activities, the site was separated into six
subsites for further investigation and eventual cleanup.
Additional remedial investigations (RI) and two operable
unit feasibility studies (OUFS) were conducted at the Galena
subsite. The RI demonstrates that the shallow ground water
within the Galena subsite contains levels of metals above primary
maximum contaminant levels (MCLs) established by the Safe
Drinking Water Act. Approximately 1,050 people who live in the
Galena subsite use this contaminated shallow aquifer for their
sole source of drinking water.
The first OUFS dealt with the provision of an alternative
water supply. A Record of Decision to provide an alternate water
supply was issued on December 21, 1987. The Cherokee County
Rural Water District (RWD) No. 8 has been incorporated to
facilitate construction, operation and maintenance of the water
system. The water system consists of two deep aquifer wells, two
elevated storage tanks and a water distribution system servicing
approximately 450 residences.
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SMUCS
CHEROKEE COUNTY
SITE BOUNDARY
S BAXTER SPRINGS AREA
JCANSAS
OKLAHOMA
FIGURE 1
SITE LOCATION
CHEROKEE CO. KANSAS
GALENA SUBSITE
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The Galena subsite is characterized by surface mine waste
features that directly impact the quality of the shallow ground
water aquifer and the surface water. The mine waste areas
contain sparse to no vegetation. Approximately 900 acres have
been disturbed by the mining activities and are partially covered
with surface mine wastes. The mined areas contain approximately
3,000 shafts including 580 open shafts and surface collapses,
many of which are direct conduits to the shallow ground water.
Short Creek and Owl Branch flow through the mined areas in the
subsite. Shoal Creek receives runoff from the mined lands. Short
Creek and Shoal Creek empty into the Spring River, which flows
through the subsite and into Oklahoma.
The City of Galena, population approximately 3,500, is
surrounded by the mine waste areas. Many houses are immediately
adjacent to the mine waste piles. Approximately 1,050 additional
people live within the subsite but outside of the city limits.
The land in this rural area is primarily used for livestock
grazing and crop production.
3.0 SITE HISTORY
Ore was first discovered in the Tri-State Mining District in
1848. The first economically significant mine in Kansas was in
the City of Galena, where ore was discovered in 1876. Sphalerite
(zinc sulfide) and galena (lead sulfide) were the important
commercial ore minerals. The district was an important source
of cadmium, which was produced as a by-product of the lead-zinc
smelting process. Pyrite and marcasite (both iron disulfide)
made up about five percent of the minerals in the Galena area. A
smelter was built along Short Creek in the 1890's. The area near
the original smelter was used for various smelting facilities
until around 1961.
Ore deposits in the Galena vicinity occur from near surface
to depths of 100 feet. This shallow depth allowed numerous small
mining operations to prosper. Exploration and mine development
were accomplished by excavating vertical shafts to locate the ore
body. Mining progressed outward from the vertical shafts using a
modified room and pillar method to follow the ore vein. The use
of vertical shafts as a means of mineral exploration and the
subdivision of leases into small mining plots resulted in a high
density of mine shafts in the subsite. Several mines have
collapsed, forming subsidences of varying sizes and shapes. Many
circular subsidences are less than 75 feet in diameter while
others, from circular to rectangular, measure several hundred
feet along the longest dimension. A ground level difference of
20 to 40 feet is common in the subsidences within the subsite.
Some subsidences are filled with water and may be deeper.
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alternative with selective placement of surface nine waste below
grade. This response activity will fill a majority of the pits,
shafts and subsidences in the subsite.
4.0 ENFORCEMENT ACTIVITIES
General notice letters were issued to inform potentially
responsible parties (PRPs) of their potential liabilities for
past activities at the Cherokee County site. Nine PRPs were sent
general notice letters in 1985. Two additional PRPs were
notified of their potential responsibility in 1986. The original
nine PRPs received notification prior to the installation of the
individual water treatment units and prior to the remedial
investigation. The PRPs indicated no desire to participate in
either the remedial investigations or the operable unit
feasibility studies.
A group of the PRPs have participated in investigatory
activities conducted subsequent to the release of the 1988
Proposed Plan. These efforts have included various laboratory
and field investigations. A laboratory study to better define
the geochemical behavior of the surface mine waste and an onsite
pilot study to assess the leaching potential of the mine wastes
were conducted under EPA oversight and/or pursuant to EPA-
approved work plans.
The EPA conducts periodic meetings with these PRPs to
facilitate information .sharing. Correspondence and summaries
of technical discussions with the PRPs are provided in the
administrative record. In May 1988, two additional PRPs were
issued general notice letters as a result of new information on
their involvement with the Cherokee County site.
5.0 COMMUNITY RELATIONS HISTORY
A public meeting was held in July 1985 prior to the remedial
investigation to discuss the planned investigation and concerns
relating to the previous mining activities. Another public
meeting was held in May 1986 at the conclusion of the remedial
investigation and prior to the removal action. At the conclusion
of the OUFS for the alternative water supply, a public meeting
was held in November 1987 and a public comment period was open
for 39 days. All public meetings were held in Galena.
As required by Section 113(k)(2)(B) of CERCLA, 42 U.S.C.
Section 9613(k)(2)(B), both the 1988 and 1989 proposed plans for
the remedial action for the ground water/surface water operable
unit were made available to the public. The information
regarding their availability was announced in a newspaper notice
and in a mailing to interested citizens. A public meeting was
held in Galena in February 1988 to discuss the 1988 Proposed
Plan. A public comment period on the OUFS and the 1988 Proposed
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TABLE 1
CONCENTRATIONS (ug/l)a OF TOTAL METALS
OBSERVED IN PRIVATE WELLS
Average
Maximum
Criteria
Barium
Cadmium
Chromium
Copper
Lead
Manganese
Mercury
Nickel
Selenium
Silver
Zinc
83.5
5.6
6.8
14.5
25.5
92
0.14
23
3.8
6.9
841
390
180
120
140
230
3,400
0.44
270
24
11
15,000
l,000b
10b
50b (total)
l,000<=d
be
50
50<
isoj
10b
50b
5,000°
a = Micrograms per liter or parts per billion
b = Primary Maximum Contaminant Level (MCL), Safe Drinking Water Act
c «= Secondary MCL, Safe Drinking Water Act
d = The proposed secondary MCL for copper is 1,300 ug/1
e = The proposed MCL for lead is 5 ug/1
f '<= Lifetime Health Advisory (EPA, Office of Drinking Water)
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sulfides. A similar action occurs on the surface with the
minerals in the waste piles reacting with oxygenated rain and
snow melt. The acidic metals-laden water is referred to as acid
mine drainage. Acid mine drainage from the waste piles, runoff
from the waste piles and contaminated ground water discharge to
the streams, each contributing to the contamination of the
surface water.
Approximately 510 households outside of the City of Galena
depend on private wells in the shallow ground water aquifer for
their drinking water. These wells are obtaining water from the
same geologic formation that had previously been mined. The RI
and OUFS show that the water from several of the private wells
contains cadmium, chromium, lead, nickel and selenium exceeding
the health-based drinking water standards. Table 1 lists the
average and maximum levels of metals observed in private water
wells during the RI for the subsite compared to the drinking
water standards.
Exposure to the metals found in the private wells may cause
harm to human health. Cadmium and chromium ingestion may cause
kidney damage with chromium also potentially adversely affecting
the liver. Ingestion of lead may cause nervous system and
irreversible brain damage particularly in children. Nickel
ingestion may affect body weight while ingestion of selenium can
cause depression and gastrointestinal disturbances.
The RI and OUFS show that the mine wastes and soils contaminated
with mine wastes also present a human health risk as a result of
incidental ingestion of the material. As several of the waste
areas are in close proximity to residential areas, exposures can
occur in a residential setting by children and adults ingesting
soil or vegetables incidentally through normal everyday
activities, (i.e., playing or working in the yard, gardening and
other similar activities). Exposures can also occur through
breathing and inhalation of dust generated by such activities.
The surface mine waste have been sources of gravel and fill
material used on residential properties. Children and adults
also are exposed to the metals in the mine wastes through
recreational use of the mine waste areas. The mine waste areas
are used for dirt bike and other off-road vehicle activities.
Table 2 lists the maximum metal concentrations observed in
surface soils and mine wastes.
Reference doses (RfDs) and acceptable intakes for chronic
exposures (AICs) have been developed by EPA for indicating the
potential for adverse health effects from exposure to chemicals
exhibiting noncarcinogenic effects. RfDs and AICs are estimates
of an exposure level that would not be expected to cause adverse
effects when exposures occur for a significant portion of a
lifespan. RfDs, which are expressed in units of mg/kg-day, are
estimates of lifetime daily exposure levels for humans, including
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Table 3
COMPARISON OF MAXIMUM DAILY INTAKES TO
RfDs AND AICs FOR SOIL INGESTION
RfD or. AIC
Metal
Cadmium
Chromium
(Total)3
Copper
Lead
Manganese
jckel
Selenium
Silver
Zinc
•M^a^B ^— ^b ••••^^
fmg/kg/davi
O.OOOS(RfD)
0.0048(RfD)
0.037(RfD)
0.0014 (AIC)
0.22 (AIC)
O.OlO(RfD)
0.0030(AIC)
0.0030(RfD)
0.21(AIC)
10 -ka Child
0.00024
0.00088
0.00048
0.0102
0.028
0.00032
0.00068
0.00128
0.022
70 -ka Adult
1.71E-5
6.29E-5
3.43E-5
7.29E-4
2.0E-3
2.29E-5
4.86E-5
9.14E-5
1.57E-3
10-kg Child
0.48
0.18
0.013
7.29
0.13
0.032
0.23
0.43
0.10
70-kg Adult
0.034
0.013
0.00092
0.52
0.0091
0.0023
0.0016
0.0030
0.0075
Hazard Index
8.88
0.6
a _
= Comparison assumes all chromium is hexavalent (VI).
DI/(RfD or AIC) greater than 1.00 indicates a health risk.
Note: Assumes daily ingestion in a residential exposure scenario with
a child ingestion rate (IR) of 0.2 gms/day and adult IR of
0.1 gms/day.
1 kilogram equals 2.2 pounds.
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11
alternatives.
8.1 EPA Studies
In May 1988, the EPA initiated studies to determine process
treatment parameters to mill and process the mine wastes. A more
detailed understanding of specific process variables was also
needed to respond to significant comments received during the
public comment period on the 1988 preferred remedy. The primary
objectives of the additional work were to collect samples of
high- and low-grade mine wastes and then conduct metallurgical
tests on these materials to better define design and operating
parameters for the treatment process proposed.
Results of onsite characterization activities indicated that
waste rock piles have a wide size distribution of materials with
corresponding highly variable metals concentrations. A portable
X-ray fluorescence (XRF) spectrometer used to semi-quantitatively
identify lead and zinc concentrations of mine waste samples,
indicated that many chat piles contained substantial lead and
zinc concentrations. Wet screening and further chemical analyses
on the chat samples showed that most of the lead was in the very
fine-sized fraction of the chat. This fine-sized fraction
includes the materials most likely to be ingested.
The results of the metallurgical tests revealed that the
milling/flotation process required for sufficient metal
(primarily lead, zinc, and cadmium) recoveries from both the
waste rock and the chat would be far more complex than originally
envisioned. For example, the waste rock was harder than
expected, so the crushing and grinding circuits would be larger
and more expensive to build and operate. In addition, these
tests determined that the quantities of metal oxide forms present
in both waste rock and chat would have to be recovered as well as
the sulfides to produce satisfactory metals removal and an
acceptable tailing. As a result, further tests and studies on
the mine wastes were conducted and the Agency developed the 1989
OUFS Supplement. This OUFS Supplement re-evaluates the 1988
preferred remedy and evaluates additional remedial alternatives
in light of the new information gathered subsequent to
publication of the 1988 preferred remedy.
8.2. PRP Studies
In addition to the studies and testing conducted by EPA, a
group of potentially responsible parties (PRPs) conducted field
investigations and leach tests. The PRP group conducted column
leach tests on waste rock, chat and a simulated mill process
tailing to better understand the geochemical behavior of these
wastes. The PRPs estimated volumes of the various mine wastes
within the subsites's eight EPA-defined waste zones. This work
indicated that there are about 550,000 cubic yards (yd3) of waste
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Table 5
GALENA SUBSITE REMEDIATION GOALS
LONG-TERM
1. Protect the Roubidoux Aquifer from contaminant inflows
within the bounds of the subsite.
2. Protect human health of the population within the subsite
from mining-related contaminants in the ground water and
surface water systems and in the surface mine wastes and
soils.
3. Meet Kansas Ground Water Contaminant Cleanup Target
Concentrations3 in ground water within the subsite.
4. Meet both Federal and State Ambient Water Quality
Criteria (AWQC) in surface streams, within the subsite.
SHORT-TERM
1. Protect the Roubidoux Aquifer from deep well contaminant
inflows within the subsite.
2. Protect human health of the population within the subsite
from mining-related contaminants in the ground water and
surface water systems and in the surface mine wastes and
soils.
3. Provide suitable drinking water (meet primary MCLs at
existing taps) for the population within the subsite".
4. Improve water quality or reduce the volume of surface
water entering the shallow ground water system within the
subsite.
5. Reduce metals loadings in Short Creek, Shoal Creek and
Spring River to support site-wide goals.
6. Improve water quality of the shallow aquifer within the
Galena subsite.
aKansas Ground Water Contaminant Cleanup Target
Concentrations are water quality criteria that apply to all
fresh and usable water aquifers (Kansas Notification/Action
Levels, KNL or KAL), and to alluvial aquifers or specific
aquifers which surface through springs or seeps (Alternate
Kansas Notification/Action Levels, AKNL or AKAL), however
these criteria are non-promulgated standards.
**A suitable drinking water supply for the subsite has been
addressed by the Alternative Water Supply OUFS.
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14
material is used as cover.
The majority of the existing chat piles have been
characterized as to their metals content. These characterization
efforts indicate that the distinction between piles of chat
containing the above-described levels of zinc is easily
determined and already appears to fall into the described
categories. Minor volumes of chat, approximately 10 percent of
the total chat volume, are estimated to contain greater than
10,000 ppm zinc. It is estimated that potentially greater than
60 percent of the chat contain concentrations of zinc at 5,000
ppm or below.
9.3 Initial Screening of Alternatives
The 1988 OUFS provides an initial screening of alternatives
which included three major steps: 1) Prescreening of general
response actions and technologies, 2) Screening of general
response actions and technologies, and 3) Development and initial
screening of potential remedial alternatives.
Twelve potential remedial alternatives were developed in the
OUFS by assembling both the source control and management of
migration general response actions remaining after the response
action and technology screening. The alternatives listed in
Table 6 were developed as required by 40 CFR Section 300.68(f) to
the extent possible and appropriate. These alternatives conform
to the requirements prescribed by Section 121 of CERCLA, 42
U.S.Co Section 9621 for remedial alternatives. As required by 40
CFR Section 300.68(g), each of the twelve potential alternatives
were evaluated based on three broad criteria: cost,
implementability and effectiveness.
The initial screening of potential remedial alternatives
provided the basis for selecting five alternatives for detailed
analysis in the 1988 OUFS. The general components of these five
alternatives are provided in Section 10.1 of this Record of
Decision. Following a detailed evaluation, EPA developed a
modification to one of the five alternatives and presented it in
the 1988 Proposed Plan as the preferred remedy, which is
described in Section 10.2, herein.
Additional investigations and information gathering as
described in Section 8.0 herein conducted after the publication
of 1988 Proposed Plan highlighted the need for further
alternative development and evaluation. Pertinent available data
passing the OUFS screening and evaluation stages were retained
for consideration in the development and further refinement of
remedial alternatives. Five alternatives were thus developed and
evaluated in the OUFS Supplement, based on information provided
in the 1988 OUFS and the information gained from the studies and
tests conducted subsequent to the publication of the 1988
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15
Proposed Plan. Many of the alternatives evaluated in the OUFS
Supplement incorporated the viable alternative components
previously considered in the 1988 OUFS. The No-Action
Alternative and the 1988 preferred remedy were considered in this
evaluation. Section 10.3 herein describes each of the
alternatives considered in the OUFS Supplement.
10.0 DESCRIPTION QZ ALTERNATIVES
10.1 1988 OUFS
The 1988 OUFS developed 12 alternatives, five of which were
evaluated in detail. A brief description of these five
alternatives is provided below. The number assigned to each
alternative discussed is the same number as in the 1988 OUFS.
Additional details regarding these five alternatives may be found
in the OUFS.
Alternative 2 - 1988 OUFS
The objective of this alternative is to remove the surface
sources of metals contamination and metals loadings which affect
acid mine drainage and to reduce the subsurface formation and
migration of acid mine drainage. This alternative consists of
four components:
1) Remove and treat surface mine wastes via milling and
flotation to remove the surface source of the contaminants and
acid mine drainage;
2) Backfill existing mining shafts and voids to reduce
direct inflow of surface water, reduce dissolved oxygen
availability to the subsurface void spaces and reduce the
permeability in the subsurface material;
3) Recontour land surface to improve drainage and reduce
surface water infiltration into the mineralized zone; and
4) Investigate deep aquifer wells and remediate as necessary
to protect the Roubidoux aquifer.
Alternative 3_ - 1988 OUFS
The objectives of Alternative 3 are the same as Alternative
2; however, Alternative 3 requires a longer time period to meet
the long-term goals. Alternative 3 consists of the following
actions:
1) Remove and treat surface wastes via milling and flotation
to remove the surface sources of the metal contaminants and acid
mine drainage;
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17
4) Recontour the disturbed areas to reduce surface water
infiltration into the mineralized zone; and
5) Investigate deep aquifer wells and remediate as necessary
to protect the Roubidoux aquifer.
Alternative 12. - 1988 OUFS
Alternative 12 is the no-action alternative. The National
Contingency Plan, 40 CFR Section 300.68(f)(l) requires that the
no-action alternative be included in the evaluation. No action
means that no further action will be taken at the site.
10.2 1988 Preferred Remedial Alternative
The 1988 preferred alternative was developed subsequent to a
thorough review of the five alternatives previously described and
evaluated in the OUFS. The objective of the 1988 preferred
alternative is to remove the surface sources of metals
contamination and metals associated with acid mine drainage,
which will improve the quality of the ground water and surface
water and reduce the threat of incidental ingestion of the metal
contaminants in the surface mine wastes. The 1988 preferred
alternative consists of four components:
1) Remove and treat surface mine^wastes via milling and
flotation to remove the surface source of the contaminants;
2) Recontour and revegetate the land surface to control
erosion and to reduce surface water infiltration to the
mineralized zone;
3) Channelize and divert stream channels to reduce metals
loadings in the streams and to reduce surface water
infiltration into the mineralized zone; and
4) Investigate deep aquifer wells and remediate as
necessary to protect the Roubidoux aquifer.
10.3 1989 OUFS Supplement
As previously stated, additional information gathered in
response to comments received on the 1988 Proposed Plan and OUFS
prompted further evaluation of the alternatives for remediating
the subsite. The first component of the 1988 preferred remedy
was reevaluated with the information gained during the post-OUFS
studies. This information caused the implementability of the
preferred remedy to be questioned. In addition, other
information gained during this period supported development of
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19
surface water metals loading. The first component provides the
following:
Remove and transport all mine waste rock and chat to a
single containment unit. The unit would be designed to meet RCRA
design criteria for hazardous waste.
Alternative £ - 1989 OUFS Supplement
The objective of Alternative 5 is to remove the source
materials from the surface and selectively place them in mine
voids to essentially eliminate the risk posed by ingestion of
metal contaminated waste. Alternative 5 would be implemented in
a manner that promotes improvement of the shallow ground water
and surface water quality. The first component provides the
following:
Remove all mine waste rock and chat and selectively place
the material in available pits, shafts and subsidences. Waste
rock would be placed below ground based on size. Chat would be
characterized as to lead and zinc content and placed below ground
or used for surface cover based on metal content.
11.0 DEVELOPMENT AND DETAILED EVALUATION ££ THE SELECTED REMEDY
11.1 Description
Alternative 5 - 1989 OUFS Supplement is the selected remedy.
The four components of this alternative are described in detail
as follows:
The selected remedy is to mine, characterize and selectively
place surface-deposited mine wastes (waste rock and chat) in open
subsidences, pits and shafts. This action will essentially
eliminate human exposure via ingestion to contaminated mine
wastes and reduce long-term shallow ground water and surface
water metals loading. The selected remedy includes diverting and
rechanneling certain surface drainages and recontouring and
vegetating the ground surface to the extent possible. These
actions will minimize recharge to the shallow ground water
system, reduce infiltration through the cover material, promote
proper surface drainage and control erosion. The selected remedy
requires investigation and remediation, as necessary, of wells
penetrating the deep aquifer to protect against contamination
from the shallow aquifer and mining-related activities.
11.2 Mining. Screening and Placement of Waste Rock
Within a given zone, waste rock will be removed, transferred
to a nearby portable screening plant and then dry screened at a
nominal two-inch size. Tests indicate that the minus two-inch
(finer) size fraction of waste rock will be highly reactive with
-------
Existing Grade
Typical Subsidence
Compacted Cover, Chat
and other Local Materials
with Metals Less than
Action Level Concentrations.
Waste Rock (Minus 2 Inch Fraction)
Chat with High Zinc
Maximum G W Elevation
Coarse (Plus 2 Inch)
Waste Rock and Low Zinc
Chat which Exceed Action Level
FIGURE 3
SELECTED REMEDY
MINE WASTE BACKFILL
CHEROKEE COUNTY. KANSAS
GALENA SUBSITE
-------
22
remediation work if necessary will be conducted on wells
identified as extending to and threatening the quality of the
Roubidoux aquifer.
11.7 Operation and Maintenance
The operation and maintenance needs for this remedy consist
mainly of maintenance of the lined channels. In addition, the
compacted chat backfill used to cover the mine wastes disposed of
in the mine subsidence areas, pits and shafts placed will require
routine inspection for erosion and settling problems. Additional
backfill may have to be placed to maintain design grades.
Vegetative cover may require additional maintenance to assure a
stabilized cover and to control erosion.
11.8 Other
Activities will be designed and implemented to mitigate
adverse health affects on the wildlife and their habitats.
Portions of the Shoal Creek and Spring River have been designated
as critical habitats for threatened or endangered species and/or
migrating birds and, therefore, must be protected during
implementation. It was believed that an endangered species of
bats inhabited portions of the subsite during the summer months.
However, a recent investigation by the U.S. Fish and Wildlife has
determined that the gray bat does not inhabit the area affected
by the remedial action.
11.9 Implementability
The selected remedy has no major implementation issues. The
technologies involved for each of the activities are available
and easily applied to the Galena subsite. Surface mine waste
removal and selective backfilling of waste rock and chat into the
mine voids present some concerns due to the instability of the
ground from subsurface mine voids within the disturbed areas.
Vegetation will require proper selection of grasses and soil
conditioning to establish a vegetative cover. The estimated time
required to implement this remedy, including detailed design, is
about three years. Additional time to establish adequate
vegetative cover may be required.
It will be necessary to obtain access to the mined areas and
areas containing surface mine wastes within the Galena subsite to
proceed with implementation. Most of the land is privately held
and individual access agreements may be obtained to conduct the
activities.
All activities will be conducted onsite, therefore,
according to Section 121(e) of CERCLA, 42 U.S.C. 6921(e), it will
not be necessary to obtain state or federal permits. Coordination
with other Federal Agencies, State agencies and EPA programs will
-------
24
During backfill of mine wastes into water-filled voids,
displacement of the water could occur. Due to the length of time
over which the backfilling will be implemented, displacement of
water will be gradual and, therefore, have minimal impact to the
quality of ground water and surface water. The time required to
complete the mine waste removal and disposal remedial actions
will be approximately two years.
11.12 Lona-Term Effectiveness and Permanence
The selected remedy will essentially eliminate the threat of
human exposure to the contaminants via ingestion by removing the
surface waste piles. The environmental risks will be reduced by
lowering the contaminant levels over the long term in the surface
waters. The pilot leach test results suggest that over the long
term the selected remedy will reduce the leaching and migration
of metal contaminants. The mass loadings model in addition to
the data from the pilot leach test supports this anticipated
decrease in the metals loading over the long term.
The metals remaining at the ground surface after
implementation of this remedy will continue to persist in the
soils and mine waste remnants. The mobility of the subsurface
metals will be slightly reduced because of the reduction in acid
mine drainage generation. Selective placement of surface mine
waste below grade, surface recontouring and surface water
diversions and channelization will assist in reducing oxygen and
water contact with sulfide minerals, therefore, reducing the
formation of acid mine drainage.
Based on the model, it is predicted that individual overall
contaminant loadings to the surface streams will be reduced by
approximately 20 to 30 percent upon completion of the selected
remedy. Contaminant-specific ARARs will not be achieved in the
short term. Completion of this remedy will positively contribute
to the long-term goal of meeting state and federal cleanup
criteria.
After implementation, operation and maintenance activities
will be required for lined channels and erosion control of
subsidence of the backfilled areas. Monitoring will be required
to evaluate long-term effectiveness because contaminants are not
removed from the site by the remedial activity. Water quality
monitoring during the first year after completion of the remedial
action and at subsequent five-year intervals will be used to
evaluate effectiveness of the remedy.
Long-term reliability of the technologies involved is
expected to be high. Selective placement of the surface mine
wastes below grade in mine voids is a permanent and irreversible
process. If the lined channels, diversion channels, recontouring
-------
Table 7
SELECTED REMEDY
DETAILED COST SUMMARY
I. Actions to Support Mine Waste Disposal Costs
A. Remove/Dispose Mine Wastes $3,714,723
B. Placement of Cover Material 1,012,302
C. Support Site Work 236,351
D. Mine Wastes Screening Plant
1. Capital Costs 192,000
2. Operating Costs 185,529
E. Supporting Field Work
1. Chat Characterization 393,400
2. Cut/Fill Engineering 197,200
II. Recontour/Vegetation
568 acres at $1000/acre 568,000
III. Rechannelization 696,000
V. Deep Well Investigation/Remediation 175,600
V. Water Quality Monitoring 170,000
PROJECT COSTS SUBTOTAL 7,541,105
Contingencies 754,110
8,295,215
OPERATION AND MAINTENANCE - ANNUAL
Cover Maintenance 10,123
Channel Maintenance 3,480
SUBTOTAL 13,603
Contingencies 1,360
14,963
-------
Contaminant
Arsenic
Barium
Cadmium
Chromium (VI)
Copper
Iron
Lead
Manganese
Mercury
Nickel
Selenium
Silver
Zinc
CWA
Human
Health
.
10
50
1,000
__
50
—
10
15.4
10
50
5,000
Table 8
CONTAMINANT-SPECIFIC ARARs
CHEROKEE COUNTY SITE
GALENA SUBSITE
Federal (SPWA) (ug/1)
Primary
50
1,000
10
50
(total)
-_
._
50
__
2
10
50
MCL
Secondary
__
__
00
1,00
300
00
50
—
— _
..
MGLG
SO
1,500
5
120
(total)
1,300
__
20
.-
3
50
—
Kansas (ug/ll
Domestic
Water
Suoolv
50
1,000
10
50
—
._
50
_.
2
..
10
50
_-
Kansas
Action
Level8
50
1,000
5
SO
1,000
300
50
SO
2
1,000
45
50
5,000
5,000
-KAL—Groundvater Contaminant Cleanup Target Concentrations for fresh, usable aquifer.
AQUATIC LIFE
Federal (CWA) (ug/1)
Contaminant
Arsenic
Barium
Cadmium
Chromium (VI)
Copper
Iron
Lead
Manganese
Mercury
Nickel
Selenium
Silver
Zinc
Aauatic
Chronic
190
._
1.1
11
12
1,000
3.2*
..
0.012
160
35
0.12
110
Life
Acute
360
_»
3.9
16
18
_„
82-
-„
2.4
1,400
260
4.1
130
Kansas tug/1)
_»
Targets
AKNL1
(Chronic)
26
0.012
5
0.12
231
AKNL0
(Acute)
42
2.4
"H
198°
255
Aquatic Life
Chronic
190
Acute
360
0.66*
11
6.5C
1,000
1.3C
0.012
88C
35
0.12
59C
1.8C
16
9.2C
„_
34e
2.4
789C
260
1.2C
65C
"Groundvater Contaminant Cleanup Target Concentration (aquifer discharge via springs or
seeps to surface). Nonpromulgated. These levels are to be considered in performing this
action.
"Alternative Kansas Notification/Action Levels applies to aquifers that surface through
springs or seeps.
^Hardness dependent (value based on C«C03 less than 150 mg/1).
"Hardness dependent (value based on 251-400 mg/1 CaCO3).
•Hardness dependent (value based on 100 mg/1 CaC03).
-------
Table 10
ACTION-SPECIFIC ARARs—FEDERAL AND STATE
Remedial Measures
Removal of Sulfide
Mineral*
ARARg
Contents
Shaft and Mine
Backfilling
30 U.S.C. 801—Federal
Mine Safety and Health
Act
40 CFR 122, 125 —
National Pollutant
Discharge Elimination
System and 40 CFR 440—
Effluent Limitation*
30 U.S.C. 801-962 —
Federal Mine Safety and
Health Act
Surface Mining Control
and Reclamation Act
30 U.S.C. ff 1201 «t. seq.
and 30 CFR Part 816, '
particularly If 816.56,
816.97, 816.106, 816.111
to 816.116, 816.133, and
816.150
Pertains to worker
safety at mining
operations
Regulates the discharge
of pollutants from any
point source into waters
of the United States or
Kansas and sets
technology-based
effluent limitation* for
point source discharge
in the Ore yi«*"e and
Dressing Point Source
Category
Pertains to worker
scafety at mining
operations
Regulates backfilling
and recontouring
previously mined areas.
and other rehabilitation
of past mining areas.
This standard is to be
considered in performing
this remedial action
Investigation/
Remediation of deep
wells, as necessary
Surface Water Channeling
Clean Water Act,
Section 404; 40 CFR,
Parts 230 and 231
Kansas Administrative
Regulation 28-30-1
40 CFR 230-231,
Section 404 of the Clean
Water Act—Dredge or
Fill Requirements
Clean Water Act, Section
404, 40 CFR 125,
Subpart M, and
33 CFR 320-330 — Rivers
and Harbors Act —-
Section 10 Permit
Action to prohibit
discharge of dredged or
fill material into
wetland without permit
Regulate construction,
reconstruction,
'treatment, and plugging
of water wells
Establishes requirements
for discharge of dredged
or fill materials, or
work in or affecting,
navigable waters
Action to dispose of
dredge and fill material
into waters is
prohibited without a
permit
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27
1. The Safe Drinking Water Act (SDWA), 42 USC §300(g), the
National Primary Drinking Water Standards, Maximum Contaminant
Levels (MCLs) 40 CFR Part 141 and the Kansas Administrative
Regulations 28-15-13 are relevant and appropriate for this
remedial action. The ground water should be cleaned up in
accordance with these requirements because the shallow ground
water is a current and potential drinking water source. Although
the MCLs are legally applicable standards promulgated for the
protection of public drinking water supplies serving 25 or more
people, the EPA believes these levels are relevant and
appropriate cleanup goals for contaminated ground water where
that water is currently or potentially a drinking water source.
The levels established by the Kansas regulations are similarly
relevant and appropriate. Table 8 identifies the MCLs
established by the SDWA and the State of Kansas drinking water
standards for heavy metal contaminants found in the shallow
ground water at the subsite.
2. Secondary MCLs and MCL goals (MCLG) are to be considered
in implementing this remedy. Secondary MCLs and MCLGs are not
legally applicable standards for public drinking water supplies
since they only provide for the protection of taste, odor and
asthetic qualities. Since these are not health-based criteria,
they are to be considered as necessary to remediate the ground
water at the subsite. Secondary MCLs and MCLGs were published in
50 Federal Register 46936.
3. The Kansas Ground Water Cleanup Target Concentrations
are to be considered in implementing this remedial action. These
target concentrations for cleanup of ground water are
nonpromulgated, but are standards used by KDHE for ground water
remediation.
4. The Clean Water Act, 33 U.S.C. §1251 et seq.. sets
criteria for surface water quality based on toxicity to aquatic
organisms and human health. The State of Kansas has similar
water quality criteria and standards, see KAR 28-16-28 and the
Ground Water Contaminant Cleanup Target Concentrations (relevant
to ground water discharge via seeps and springs to surface
waters). These laws and regulations are guidelines and are not
legally applicable or enforceable requirements. However, these
requirements are relevant to the protection of the environment at
the subsite. The remedial action will monitor the surface water
quality to measure the improvement in water quality and compare
the results with these guidelines.
Location-Specific ARARs
The location-specific ARARs that will be attained by this
remedial action are based on the location of the subsite and the
affect of the hazardous substances on the subsite environment.
-------
29
this requirement is to be considered in the implementation of
this remedy in order to preserve possible historic property which
may be encountered in the subsite. Certain mining property may
remain in such condition that historic preservation may be
desirable. When practicable, consideration should be given to
proper historic preservation if such mining property is found
during implementation of this remedy.
6. The National Archeological and Historic Preservation
Act, 16 U.S.C. §469, and 36 CFR Part 65 require recovery and
preservation of artifacts which may be discovered during
government actions. This requirement is to be considered in the
implementation of this remedy in order to preserve artifacts
which may be found at the subsite. The remedial action includes
removal and placement of surface mine wastes. This activity may
reveal significant scientific, prehistorical, historical or
archeological data. (For example, prehistorical Native American
burial grounds and villages or historical mining camps, could be
discovered although not likely.) Therefore when practical,
consideration should be given to preservation if such artifacts
are found during implementation of this remedy.
Action-Specific ARARs
The action-specific ARARs will be achieved by the selected
remedy. These ARARs are based on activities and technologies to
be implemented at the subsite. The following lists describe the
action-specific ARARs shown in Table 10:
1. The Federal Mine Safety and Health Act, 30 U.S.C. §801,
is a legally applicable requirement for this remedy. This act
pertains to worker safety at mining operations. The remedial
action includes removal of mine waste rock and chat and the
filling of mine shafts, pits and subsidences. These activities
are regulated to protect workers performing these actions.
2. The National Pollutant Discharge Elimination System,
Effluent Limitations, 40 CFR Parts 122, 125 and 440 are relevant
and appropriate limitations for this remedial action. The
regulation at 40 CFR Part 440 sets technology-based effluent
limitations for mine drainage from mining-related point sources.
The remedial action includes the removal and processing of mine
waste rock and chat. Such activities are sufficiently similar to
mining and processing of lead and zinc ore that the effluent
limitations are relevant and appropriate in the event that mine
drainage is generated during the implementation of this remedy.
Although the permitting requirements of the NPDES regulations are
also relevant and appropriate, such permit is not required
because this remedy will be conducted onsite, according to
Section 121(e) of CERCLA, 42 U.S.C. Section 9621(e), no federal,
state or local permit shall be required for any portion of a
remedial action conducted entirely onsite.
-------
31
waste sites performing remedial actions. These regulations
control whenever the OSHA or MSHA might overlap or conflict with
these regulations.
8. The Centers for Disease Control (CDC) and the Agency for
Toxic Substances and Disease Registry (ATSDR) have performed
studies in residential areas to determine health-based levels of
concern for exposure to lead contamination in soils. The
health-based levels established by CDC and ATSDR are to be
considered in implementing this remedy because EPA has no
promulgated standards for heavy metals contamination in soil.
The health-based levels to be considered for this action are
1,000 ppm lead and 25 ppm cadmium. Much of the mine waste rock
and chat at the subsite contain heavy metals in excess of these
health-based levels.
9. Deed restrictions are institutional controls that the
State of Kansas and the local government will enforce to protect
the construction of the remedial action. Restrictions to be
considered in the implementation of this remedial action, include
restrictions on future mining activities, water well
construction, excavation of backfilled shafts and subsidences and
other construction in the areas affected by this remedial action.
The State of Kansas may consider establishing a Ground Water
Management District program for the subsite to limit the use of
shallow ground water for drinking water, pursuant to Kansas
Administrative Regulations 28-30 and K.S.A. 82a-1036.
11.15 Overall Protection of Human Health and the Environment
This remedy protects human health by removing the exposed
surface mine wastes that exceed the action level for lead from
human contact and subsequent ingestion. Placement of the wastes
below grade will effectively mitigate the potential for
incidental ingestion. Since ingestion of surface mine waste
represents the most significant exposure pathway for children,
removal of the mine wastes will substantially protect the health
of children.
Selective subsurface disposal of the surface mine wastes in
conjunction with surface water channelization and recontouring
should result in reduced metals loading in the ground water and
surface water systems, but shallow ground water quality will
continue to exceed contaminant-specific ARARs. The alternative
water supply operable unit for the Galena subsite provides a
suitable drinking water source to users who depend on the
contaminated shallow ground water system.
Removal of the surface mine wastes and installation of lined
diversion channels will significantly reduce the metals loading
entering the surface waters through runoff and acid mine drainage
from the waste piles. Over the long-term, surface water
-------
33
contaminated water to the deep aquifer. The deep aquifer is used
as the primary source of drinking water for many communities.
11.16 Community Acceptance
The community has shown a positive response to the preferred
remedy presented at the August 3, 1989 public meeting. EPA's
response to comments received from the public including those
received from the potentially responsible parties are included in
the Responsiveness Summary portion of this Record of Decision.
11.17 State Acceptance
The Kansas Department of Health and Environment has worked
closely with the EPA in the review of the pertinent information
and development of the selected remedy. A letter of concurrence
on the selected remedy has been submitted by the State.
12.0 SUMMARY fi£ THE COMPARATIVE ANALYSIS OF. ALTERNATIVES
In the OUFS, EPA conducted a detailed analysis of each of
the potential remedial alternatives, in accordance with the
requirement of the NCP, 40 CFR Section 300.68(h). The analysis
included: 1) Refinement of the feasibility of the alternative;
2) Detailed cost estimation, including operation and maintenance
costs and distribution of cost over time; 3) Evaluation in terms
of engineering, implementation, reliability and constructability;
4) An assessment of the extent to which the alternative
effectively prevents, mitigates or minimizes threats to and
provides adequate protection of public health and welfare and the
environment; 5) An evaluation of the extent to which the
alternative attains or exceeds applicable or relevant and
appropriate federal and state public health and environmental
requirements; 6) An analysis of whether recycle/reuse or other
advanced, innovative or alternative technologies is appropriate;
and 7) An analyses of any adverse environmental impacts.
The alternatives considered in the detailed evaluation were
compared to CERCLA criteria for selection of the remedy as
defined in Section 121 of CERCLA, 42 U.S.C. Section 9621 and EPA
Office of Solid Waste and Emergency Response (OSWER) Directives
9355.0-19 and 9355.0-20. These remedy selection criteria
include: 1) Implementability; 2) Reduction of toxicity, mobility
or volume; 3) Short-term effectiveness; 4) Long-term
effectiveness and permanence; 5) Cost; 6) Compliance with ARARs;
7) Overall protection of human health and the environment; 8)
State acceptance; and 9) Community acceptance.
The 1988 OUFS provided a preliminary evaluation of twelve
alternatives and detailed evaluation of five alternatives refined
from the original twelve. These alternatives were evaluated
based on the information available at the time. Subsequent to
-------
Table 11
ETALUATION OF ALTERNATIVES
Criteria
Alternative 1
Rb Action
OVERALL
Hi-am Health Protection
• Direct Contect/Hlna Maetee
Ingeet Ion
Cxletln*. health threat froa
*urf*ee ere** coataalnated with
U»d greater thm Ktlon level.
Alternative I
Him and Mill
Al 1 Mine Heate*
All contealnetod eurface (olid*
above act loo level In dleturbed
areee reaoved.
Alternative J
Him nil Mill
All Hlne Uaate Hock
and IUII ol th« Chat
All contaminated auriaee aolltf*
•hove action lavel In dleturbed
•n» reamed.
Alternative »
Him and Dlepoaa of alt
HIM Ueatee In Onalte
Containment r«cllltT
All contaalmted aurfaca (olid*
above action level In dleturbed
ere** rtaoved.
Alternative »
Oaochealcetly Characterlto
Weatea, Segregate by Sin,
Selectively Backfill, md
. Raconteur
All contaminated aurfac* eollda
above action level In dlaturbed
art** na»«ad.
- Croandvatcr InMetlon
CmlmaMntal Protactlon
CPtrtlAUg WITH OAKS
Chanlcal-SDtciric AKAIU
Locatlon-SiiKiric
ARAM
Actloa-Spaciflc AMIto
drlnklni vatar atandarda
Altcrnata vatcr
for ulittnt uaara being
Brortdad through other reead*.
ODntaatnated wtara exceed AW)C
In Short Creek and other ear face
water*.
MB action doe* not mat
chealcel-apeclflc ARAIta.
Rot relevant for no action.
Actloa-epaclfte MARa ere not
relevant.
Other Criteria and Outdance
Vbald not protect hnaan Mpoeara
to lead levele greeter than
action level In mate rock and
chat.
rrteery drinking vater atanderde
exceeded. Alternate veter
aupply for eslatlng aaera being
provided through other reactfv.
Heaa natal loada reduced but
nater quality atlll doea not
acet AUQC.
Doae not aaet chealcal-apeclflc
ARAfte but vtll reduce •»•• natel
loading.
racllltte* dealgned to wet
locatlon-apaclflc ARAR*.
Killing and Billing action* xould
be eaelgned to coanly vlth
JO USC 801-WJ. Hilling plant
•onld be deelgned and operated
to acet appropriate KPKS
dlacharge reomlreaonta Including
M> CTR MO.
The air oalaalona froa the
all ling operetlon nould be
dealgned to met the criteria of
Ml CFR tl.
All contaminated aarface aollda
•ithln dlaturbed areaa exceeding
lead action level reaoved.
rrteary drinking «atar etanderde
exceeded. Altemete water
aupply for ealatlng uaere being
provided through other reaady.
Haaa aatal loade reduced but
vater quality atlll doea not
aret AUQC.
Doe* not aaet chaalcal-epeclflc
ARAR* but wilt reduce aaaa aetal
loading.
racllltlee dealgned to aaet
locetlon-apeclflc ARARa.
Thl* alternative would have the
earn actlon-apaclflc ARARa to be
conetdered ea for Alternative 1.
rrtaary drinking vater etandarda
exceeded. Alternat* aater
aupply for exlatlng uaera being
provided through other reaady.
Haaa aatal load* reduced but
vater quality atlll doae not
acet AUQC.
Doe* not aaat chaaicet-apaclftc
ARARa but will reduce aaaa aatal
loading.
racllltle* daelaned to aaat
locatlon-apeclflc ARARa.
TM« •Krmattve would naad to
cooalder RCRA dealgn paraaater*
for the contatnatnt unit.
rrlaary drinking water atendarda
exceeded. Alternate vater
aupply for exletlng aaera being
provided through other reaady.
Haaa aatal loada reduced but
water quality atlll doea not
met AWQC.
Doe* not aaet cheartcal-apeclflc
ARAR* but will reduce aeaa
aaaa aatal loading*.
racllltlea deelgnod to aaet
locatlon-apaclflc ARARa.
Thla alternative would need to
conelder JO USC «01-M2 for
action* around the ahafta.
All contaainetad aurfece aotlda
vlthtn dlaturbed areea exceeding
lead action level teaoved.
All eentarinantad aurface aollda
within dlaturbed area* exceeding
teed action level reaoved.
All contaminated aurface aollda
within dlaturbed areaa exceeding
lead action level reaoved.
i Emcnmass AMD
Nagnltudi of Real dual Rl*k
- Nine Waate Ingeatlea
HIM aatal lead* not reduced.
Rb long-tera change* to current
rlak.
Salfate, sine, and cadalu* net
a*.* loada reduced 17.6, H.I.
and J1.7V
Alternative peraanantly reaovee
Ingeatlon rlak froa thoea arcaa
where aloe vaate rock and chat
are reaoved.
Sutfate, tine, and caoatua net
aeaa loada reduced 2*.S, 31.1,
and n.k\.
Alternative peraanantly reaovea
Ingeatlon rtek froa thoaa ereaa
where aim vaate rock and chat
are reaoved. Realdual rlak aub-
atanttally reduced due to
reaoval of actala In contami-
nated eurfece aollda.
Sol fata, line, and cadaltai net
aaa* load* reduced 27.*, M.I,
and J1.7V
Reelduel rl*k reduced elnce
level of mtel* In raaatalng
aurfaca aollda lea* then action
levele. Maul contaalnanta
reaaln onalte.
Sulfate. itnc, and eadattai mt
aaaa loada reduced IB.*. 2«.l,
and 15.t\.
Alternative reaovea Ingeatlon
rl*k froa thoae are** where aim
waate rock and chat are reaoved.
-------
T*ble 11
(continued)
Criteria
trreveralblo Treatment
Type end quantity of Reeldual*
Remaining Alter Treatment
SHOW-TOM tTTtCTiyPCESS
nltr Protection
worker Protection
ll Impact*
Alternative 1
Ho Action
TlM wntll Action 1* Complete
Not applicable.
HIM weet* rock and chat will
continue to Mather, releasing
Mtela to ground and eurlace
water.
Uik to community not Increaaed
by remedy Implementation.
No rl*k to worker*.
Centime** Impact from ealattng
condition*.
Nat applicable.
Alternative 1
Mine and Hill
All Mil* Waetea
Nllllnii and flotation are
Irreverelble treatBrnta.
Low level* of Mtala with con-
centration* leao than action
tevele, main In Bill tilling.
Temporary IncreaM of duat pro-
duction and truck traffic (haul-
age of Mete rock and chat to
•III).
Protection fro* duat eipoeure I
and dermal contact vlll be
required. Uorkere wet be
cmutlou* concerning unatabl*
(round condition*.
A* mine mat* rock la reamed,
contaminant male load wilt
decreaae.
3-1/2 to 4 year*.
Alternative 1
Nine and Hill
All Nine Waate Rock
and Half ol the diet
Hilling and flotation are
Irreverelhle treatavnta.
No contanlnated aurface "In
vaate reuin* on*lte.
Teafiorary tncreaae of duat pro-
duction end truck traffic (haul-
age of weece rock and chat to
•111).
frotectlon froai duat eipoaure
end demel contact will be
required, worker* eu*t be
cautloua concerning unatabl*
ground condition*.
A* (Jin* waate rock I* reenved,
contaminant •*•• load will
decree**.
3 to 3-1/1 yeara.
Alternative •
Nine and DlcpoM of ill
Htn* Uaete* In Onalte
Contalnajent Facility
not *ppltc*bl*.
Contaalneted watte rock and chat
will be contained onalt*.
Teaporary Incre*** of eu*t pro-
duction and track traffic
(haulage of waate to containment
unit).
Protection fro» du*t expoeur*
end dermal contact will be
required, worker* mat be
caution* concerning unetabl*
ground condition*.
A* nine waate rock 1* milled,
contaminant neaa load will
decreaca.
About 1 year.
Alternative )
Gaochenilcal ly Characterlte
Waatea, Segregate by Site,
Selectively Backfill, and
Raconteur
Treatment not Irrereralble.
OontMlnated Mate rock and chat
will be aelectlvely laolated,
controlling Betel releaaea to
the groundwatar end human
eiipoaur*.
MnlMl Impact to community
during Implementation.
frotoctlon from duet eipoeure
and dermal contact will be
required. Workera mult be
cautloua concerning unatabl*
ground condition*.
Minimal Impact to environment
during Implementation.
About 1-1/2 yeer*.
Ability to Gonatrnct/Operato
Technology
Not eppltcabl*.
Reliability of tin Technology
Not applicable.
Caee of Doing Nor* Action If
Not applicable.
Conventional recovery, transport,
and benaflclatlon technolofle*
are ***tly tepleaentibl*.
However, enhanced recovery to
•eet action level require*
lnnov*tlv* technologic*.
••channeling, recontourln(,
revetetatlon, end well media-
tion are all conventional tech-
•oloflea that ahould be eaajt to
R*II«blIlrv of tr**ta*nt procei*
require* eonltorlng of feed and
tailing product quality.
The reliability of the recon-
tourlng, channelliatlon,
reve^etetton, and well
roMdlatlon will depend on
routine Mlntenance.
Alternative reenvea and treata
all eurfic* nine weate*.
Convention*! recovery, tranaport,
and beneflctetlon technologlea
are eaelly lajpleaentable.
However, enhanced recovery to
•eet action level require*
Innovative technoloRlea. Inno-
vative uae of XRF technology
wilt provide charecterliatlon of
chat. Rechannellng, recontour-
Ing, r«vet*tatlon( and well
mediation ere all conventional
technologle* that ahould be eaay
to lajplenent.
Rcllablllry el treatMnt proc***
require* eonltorlng of feed and
tilling product quality. Kali-
ability of the chat XRF charac-
terisation operation* will be
controlled through detailed
procedure*.
The reliability of the racon-
tourlng, chmnelliatlon,
reveeetatlon, and w*ll
mediation will .lepend on
routine Mlntenonce.
Additional chat could be
reaoved.
OontalnMnt tnchnology eaay to
tepleaant. Conatructlon
•aterlele would hev* to be
hauled to elte. (.channeling,
recontoorlng, revegetatlon, and
Mil reMdlatlon ere all conven-
t lone I technologle* that ahould
be ***y to UpleMnt.
Omtalnjeent wnlt would be con-
• trocted to here klaji opera-
tional reliability. Reliability
of the chat XRF character I tat Ion
operation* would be controlled
through detailed procedure*.
The reliability of the
recontourlng, chmnallutloMl
reveejetatlon, and Mil
reewdlatlon trill depend on
routine Mlntenance.
Uaatea could be leter retrtered
for treataent or other dlepoeel.
Innovative Me of OUT technology
will provide charactarliatlon of
chat. Siting proceaa for waat*
rock MgregatlM I* ataadard
technology hence eaclly Imple-
Mntabla. leolatlon of contaml-
n*t*d aaterlel* employ* conven-
tional earthmovlng technologlea.
Rechannellng, recontourlng,
revegetatlon, and wall remedia-
tion are ell conventional tach-
mologl** that ahould be aaiy to
Implement.
Earttmnvlng technologlea are
reliable. Reliability of «w
chat ni* characterltatlon opera-
tion* will be controlled through
detailed procedure*.
The reliability of the recon-
tourlng, channelltetton,
revegetatlon, and well
remediation will depend on
routine maintenance.
Additional action* very
difficult.
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35
12.4 Loncr-Term Effectiveness and Permanence
Alternatives are assessed for the long-term effectiveness
and permanence they afford along with the degree of certainty
that the remedy will prove successful. Pursuant to this
criterion, the magnitude of residual risks following
implementation, type and degree of long-term management required,
potential of human and environmental exposure to the remaining
wastes, long-term reliability of the controls and the potential
need for replacement of the remedy are assessed.
12.5 Cost
The cost criterion includes capital costs, operation and
maintenance costs, costs of five-year reviews, net percent value
of capital and O&M costs and potential future remedial action
costs.
12.6 Compliance with ARARs
Section 121(d) of CERCLA, 42 U.S.C. Section 9621(d),
requires that remedial actions shall attain a degree of cleanup
of hazardous substances released into the environment and a
degree of control over further release that at a minimum assures
protection of human health and the environment. It requires that
any Federal or State law, standard, requirement, criteria or
limitation which -is legally applicable to the hazardous substance
or is relevant and appropriate under the circumstances shall be
the level or standard of control for such hazardous substance or
contaminant remaining at the site. The applicable or relevant
and appropriate requirements (ARARs) for remedial alternatives at
this subsite include contaminant-specific ARARs, location-
specific ARARs and action-specific ARARs.
12.7 Overall Protection of Human Health and the Environment
This criterion is used to assess the alternatives from the
standpoint of whether they provide adequate protection of human
health and the environment.
12.8 State and Community Acceptance
The state and community acceptance criterion is used to
assess support and opposition to the components of the
alternatives provided at the state government and local community
level.
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37
The no-action alternative fails to address any
improvement in surface water or ground water quality
(shallow or deep aquifers); and
The no-action alternative fails to reduce mobility,
volume or toxicity of hazardous substances at the site.
Alternative 2. - 1989 OUFS Supplement
Alternative 2 obtains the same level of protection for
the public health risk due to incidental ingestion of
surface mine waste, however, the costs are nearly 2.5
times as expensive as the selected remedy.
• Although Alternative 2 does achieve greater improvement
in the surface water quality compared to the selected
remedy, it still does not meet contaminant-specific
ARARs. Thus, the greater costs are not justified.
Alternative 3_ - 1989 OUFS Supplement
Alternative 3 obtains the same level of protection for
the public health risk due to incidental-ingestion of
surface mine waste, however, the costs are nearly 2.0
times as expensive as the selected remedy.
* Although Alternative 3 does achieve greater improvement
in the surface water quality compared to the selected
remedy, it still does not meet contaminant-specific
ARARs. Thus, the greater costs are not justified.
Alternative ± - 1989 OUFS Supplement
Alternative 4 achieves the same level-of protection for
public health, however, the costs are greater than 3.5
times as expensive as the selected remedy.
* Alternative 4 achieves a greater improvement in the
surface water quality, however, it still does not meet
the contaminant-specific ARARs, thus the greater cost
remain unjustified.
* Alternative 4 would be difficult to implement due to
anticipated problems in finding a location for a single
unit to contain all waste material.
* Alternative 4 is unacceptable to the state.
In general, the selected remedy was chosen for
implementation on the basis of the remedy selection criterion and
the evaluation of various alternatives according to the NCP
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39
(F) In the case of a remedial action to be undertaken
solely under Section 104 of CERCLA, 42 U.S.C., Section 9604,
using the Fund, selection of a remedial action that attains such
level or standard of control will not provide a balance between
the need for protection of public health and welfare and the
environment at the facility under consideration and the
availability of amounts from the Fund to respond to other sites
which present or may present a threat to public health or welfare
or the environment, taking into consideration the relative
immediacy of such threats. Where any of the above conditions
occur and ARARs cannot be achieved by the selected remedy, EPA
may "waive" the specific ARARs.
The selected remedy will not meet the contaminant-specific
ARARs for the ground water and surface water. These ARARs
include attaining the MCLs in the ground water and the AWQC in
the surface water and the equivalent state standards. The
selected remedy will not attain these ARARs due to technical
impracticability as described above in condition (C). It is
technically impracticable to meet the ARARs because of the
continued presence of waste materials remaining onsite and
contaminants offsite and upgradient of the Galena subsite.
Consistently, Short Creek exceeds standards at the point where it
enters the subsite and at times, the Spring River exceeds
standards at the point where it enters the site.
In the initial screening of alternatives, EPA considered
whether any alternative exists which would achieve contaminant-
specific ARARs. The only technology that possibly would
remediate the site to achieve these ARARs is to treat all surface
mine wastes and strip mine the remaining mineralization in the
Galena subsite. This alternative has several implications on the
environment and human health, including, but not limited to,
destruction of an endangered species habitat, removal of all
surface soils and permanent relocation of the town of Galena.
The EPA also concluded that the costs of such an alternative
could exceed the available funds in the Hazardous Substance
Superfund. Finally, even with this alternative, it could not be
accurately predicted whether contaminant-specific ARARs would be
achieved because it may not be possible to completely remove all
the mineralization. In addition, upgradient sources of
contamination may continue to degrade water quality within the
Galena subsite.
13.5 Monitoring of Selected Remedy
The surface water quality will be monitored on Short Creek
approximately one mile upgradient of the Spring River to
determine the actual effectiveness of the remedial action. The
frequency of the monitoring will be determined during remedial
-------
41
Following implementation of the action, the metals
contaminants in the shallow ground water will continue to exceed
maximum contaminant levels as set by the Safe Drinking Water Act
and the equivalent state standards. The surface water will
continue to exceed ambient water quality criteria for the
protection of aquatic life as set by the Clean Hater Act and the
equivalent state standards. Implementation of an action in an
attempt to meet these ARARs would present a greater risk to the
environment than currently exists and than will exist under the
selected remedy. In addition, it is technically impractical to
implement an action to meet ARARs at this subsite. Tables 8 and
9 on location-specific and action-specific ARAR's, presented in
Section 11 herein, document the ARARs which will be attained by
the selected remedy.
All activities of the selected remedy will be conducted
onsite and, therefore, permits are not required according to
Section 121(e) of CERCLA, 42 U.S.C. Section 9621(e).
Coordination will be conducted with Kansas agencies, other
Federal agencies and EPA programs.
Cost Effectiveness
The selected remedy is cost-effective. It provides overall
effectiveness proportional to its costs such that the remedy
represents a reasonable benefit for the cost expenditures. In
conjunction with the alternative water supply operable unit, the
selected remedy will substantially mitigate the public health
threats identified at the subsite. The selected remedy will
provide a reduction in the contaminants of concern in the stream
water which will improve surface water quality. This alternative
also provides protection to the Roubidoux aquifer, the regional
drinking water source. The selected remedy provides less
protection to the environment than some of the other
alternatives evaluated, but provides equal or better protection
to the public health. The selected remedy is less expensive than
the other alternatives evaluated.
Utilization of Permanent Solutions
The selected remedial action of screening the mine waste
rock and selectively placing that material below grade based on
its geochemical character provides a solution that permanently
removes the surface mine wastes from the surface. The wastes
after placement will not be removed from the mine voids.
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RESPONSIVENESS SUMMARY
Record of Decision
for the
Ground Water/Surface Water Operable Unit
Galena Subsite, Cherokee County
INTRODUCTION
This Responsiveness Summary presents responses of the
Environmental Protection Agency (EPA) to public comments received
regarding remedial actions for the ground water/surface water
operable unit at the Galena subsite in Cherokee County. This
document addresses significant comments received by the Agency
during the two comment periods held during the remedy selection
process.
The EPA and Kansas Department of Health and Environment
(KDHE) have developed and selected an operable unit remedy to
remediate the ground water/surface water at the Galena subsite in
Cherokee County. The selected remedy and other potential
alternatives were evaluated in an operable unit feasibility study
(OUFS). The OUFS considered the available information pertinent
to improvement of the ground water and surface water quality and
protection of the Roubidoux aquifer. The OUFS is comprised of
the March 1988 OUFS and July 1989 OUFS Supplement.
A public meeting was held on August 3, 1989 to present the
preferred remedy to the public and to receive comment. A public
comment period was open from July 25 to August 28, 1989. A notice
-------
was published in the Joplin Globe and Galena Sentinel, which
announced the public comment period and the availability of the
Proposed Plan, OUFS Supplement and updated Administrative Record.
A Proposed Plan was also developed in 1988 in conjunction
with the 1988 OUFS. This Proposed Plan outlined the preferred
remedy that was presented to the public at a meeting on February
28, 1988. The EPA provided a public comment period between March
7 and April 29, 1988,,for comment to the 1988 Proposed Plan and
1988 OUFS. Notice of the February 1988 public meeting and public
comment period was published in the Joplin Globe.
This Responsiveness Summary will address comments received
during both of the above described comment periods. Part 1 will
address those comments received to the 1988 Proposed Plan. In
addition, Part 1 will address comments received from a
potentially responsible party (PRP) group to the Alternative
Water Supply OUFS at their request. Part 2 will address those
comments received to the 1989 Proposed Plan. Both parts provide
responses to comments received from the public, including city,
state and federal officials and agencies and PRPs.
I. Comments to the 1988 Proposed Plan
Responses to comments received between March 7 and April 29,
1988, give the Agency's perspective on the issues at the time the
comments were received. In addition, the responses provide the
Agency's current perspective as affected by the 1988 remedy
selection process and details of the selected remedy.
-------
A. Comments from the Public
1L Comment: Two commenters express concern about the
metals uptake of plants. One of the commenters is concerned
about current vegetable gardens. The other is concerned about
the area to be revegetated in the project. The later commenter
suggests that special soil treatment to fixate the metals should
be used or land use restrictions for those areas should be
established.
Response; The EPA will conduct activities that place mine
wastes containing metals at levels of concern below the ground
surface under a vegetated cover. Plants can uptake metals from
the soil and water. Specific rates of uptake or levels of metals
in area plants is not available. The selected remedy will remove
the mine wastes from the surface, which act as a source of
metals. This action over the long term will decrease the
exposure to area plants. During the design of this action a
determination will be made on the type of vegetation to be used.
The State of Kansas or local government will be responsible for
providing all land use restrictions after the area has been
recontoured and revegetated, to assure future integrity of the
cover.
2. Comment; A commenter questions if the project includes
stabilization of areas where the chat piles have already been
removed.
-------
Response; Areas where chat piles have been removed will be
stabilized if there are significant quantities of surface mine
wastes remaining in close proximity. Those areas included for
stabilization will be delineated during the remedial design. The
areas within the Galena subsite in close proximity with the
remaining surface waste accumulations where chat piles have been
removed will be stabilized by compacting filled areas and
recontouring and revegetating the cover material.
3. Comment; A commenter suggested that we should mix four
parts waste rock with one part concrete and use the mixture to
line the stream bed. The commenter stated that $3,537,500 would
be needed for the concrete to bind up all the waste rock. He
stated that the need for a mill would be eliminated with his
suggested plan.
Response: Use of the mine wastes for lining the streams is
/
of concern because the metals could leach out of the concrete if
not properly maintained and continue to present a health threat.
The type of concrete mix and proportion of ingredients to be used
will be determined during the design phase.
4. Comment: A commenter stated that a strategy should be
developed to evaluate the improvements in aquatic habitat as the
result of the remediation.
Response; The EPA agrees with the commenter and will
develop a plan to monitor the improvements. The plan will be
developed during the design activities.
-------
5. Comment; A commenter indicated that it would be good to
fill in subsidences and visible rooms.
Response; The EPA agrees with the commenter in part. Some
subsidences will be filled as a part of the remedial action. The
filling will be conducted in a manner that promotes proper
•
drainage and prevents erosion.
6. Comment; The commenter asked if we planned to fill
shafts. He said that the shafts he has backfilled that do not
connect to drifts are successful. The commenter also stated that
fill placed in shafts that connect to drifts settle and are not
successful. ,
Response; The EPA understands the problem and is intending
to fill as many mine voids, pits, shafts, subsidences open to the
surface as possible. The affected shafts will be covered, and
recontoured and vegetated to the extent possible. Details of
i
this activity will be clarified during the remedial design phase.
B. Comments from the PRPs Received During the 1988 Public
1. Comment; Some commenters suggested EPA's 1988 proposed
remedial action at the site was intended to cleanup the ground
water/surface water (GW/SW) beyond the quality of the water in
its premining condition.
Response; The EPA's proposed remedial action in 1988 for
ground water/surface water cleanup at the Galena subsite was
proposed on the basis of achieving protection of human health and
the environment and the requirements of the Comprehensive
Environmental Response, Compensation and Liability Act of 1980
-------
(CERCLA) as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA), 42 USC Section 9601 et seq.
and the National Contingency Plan (NCP). The EPA determines
appropriate cleanup standards for water on the basis of potential
uses for the water. The degree of cleanup is determined in
accordance with Section 121(d) of CERCLA, 42 U.S.C. Section
9621(d).
The shallow ground water aquifer subject to remedial action
is used directly for drinking water (without treatment) and may
continue to be utilized directly for such purposes. The
applicable or relevant and appropriate cleanup standards for such
waters are the Maximum Contaminant Levels (MCL) established
pursuant to the Safe Drinking Water Act (SDWA). These same
cleanup levels^ along with additional standards, are implemented
by the State of Kansas through the Kansas Ground Water
Contaminant Cleanup Target Concentrations. These Kansas Action
Levels (KAL) apply to all fresh and usable aquifers and are
"applicable" for the Galena subsite remedial action. The surface
water subject to remedial action is and may continue to be used
for aquatic life and recreational purposes. According to Section
121(d) of CERCLA, the applicable or relevant and appropriate
cleanup standards for such surface waters include, but are not
limited to, the Federal Ambient Water Quality Criteria for the
protection of aquatic life and the Kansas Surface Water Quality
Standards.
-------
Although EPA acknowledges that hazardous substances may have
been released into the ground water and surface water in the
Galena subsite from the presence of the natural ore prior to
mining activities, EPA has no conclusive evidence that the water
quality exceeded the SDWA standards in its premining condition.
On the basis of best scientific judgment, the EPA believes that
the mining activities exacerbated the release of hazardous
substances into the ground water and surface water because the
mining activities significantly altered the hydrogeology of the
Galena subsite, and the surface mine wastes left by miners
contributes to the formation of acid mine drainage which
continues to degrade the water quality of the subsite.
2. Comment; The commenters state that the Federal Ambient
WaterjQuality Criteria, Kansas Surface Water Quality Standards,
the Safe Drinking Water Act MCLs and the Kansas KALs are not
legally applicable or relevant and appropriate requirements
(ARARs) for the ground water/surface water remediation at the
Galena subsite.
Response; According to Section 121(d) of CERCLA, 42 U.S.C.
§9621(d), the remedy selection process requires consideration of
cleanup levels for remediation of Superfund sites where any
hazardous substances remain onsite at completion of the response
action. The AWQC, MCLs, and KALs are ARARs for the ground
water/surface water remediation due to the uses and potential
uses of the shallow ground water for drinking water,
agricultural and aquatic life. The surface water is the habitat
-------
for a variety of aquatic life; for example the Spring River Basin
is a critical habitat for the Eurycea multiplicata griseogaster,
a species of graybelly salamander, a Kansas endangered species.
3. Comment: The commenters suggest that a variance from
KALs is appropriate because contamination at the site is due to
"natural pollution".
Response; The Kansas Surface Water Quality standards
recognize that naturally occurring minerals may result in
"natural pollution" of surface waters and in such situations a
variance from the Kansas standards may be secured, KAR 28-16-
28(c)(3). However, the Kansas variance procedure is
inappropriate for the Galena subsite. Contamination from the
Galena subsite is inconsistent with the Kansas definition of
"natural; being in a state of nature untouched by influences of
civilization and society," KAR 28-16-28(c). Since mining
activities influenced and touched the ore body, the contamination
cannot be the result of "natural pollution" in accordance with
the Kansas definition.
4. Comment; The commenters state that the long-term goals
for the subsite are inappropriate. They believe that achieving
the long-term goals will result in conditions better than the
naturally occurring conditions. They state that such long-term
goals are arbitrary and capricious and, therefore, unlawful and
outside of the scope of CERCLA.
Response; The long-term goals for the ground water/surface
water remediation at the Galena subsite include: 1) Protect the
-------
Roubidoux aquifer from contaminant inflows, 2) Protect human
health of the population from mining-related contaminants in the
ground water and surface water systems and in the surface mine
wastes, 3) Meet Kansas Ground Water Contaminant Cleanup Target
Concentrations (Note: These include the Maximum Contaminant
Levels established by the Safe Drinking Water Act) in the ground
water and 4) Meet both Federal Ambient Water Quality Criteria
(AWQC) and Kansas Ambient Water Quality Criteria (Kansas Surface
Water Quality' Standards) in surface streams.
The first long-term goal is appropriate for the subsite
because EPA has determined that the Roubidoux aquifer is
threatened by contaminant inflows from the shallow aquifer. The
Roubidoux aquifer is used as the water source for several public
water supplies in the Cherokee County area. The contamination may
occur through deep wells or boreholes. Improperly cased or
corroded wells and uncased boreholes that penetrate the
contaminated shallow aquifer and the deep aquifer could allow the
migration of the contaminants from the shallow aquifer to the
Roubidoux aquifer. Contaminant migration also may occur through
potentially permeable rock layers separating the shallow and deep
aquifers. Although the EPA believes the rock layers between the
aquifers are generally impermeable, some scientists have
indicated that shallow ground water may reach the deep aquifer
through voids or fractures in the impermeable rock layers. On
the basis of these potential contaminant pathways and the use of
the aquifer for a public water supply, EPA developed this long-
-------
10
term goal for the subsite that the Roubidoux aquifer should be
protected from contaminant inflows from the shallow aquifer.
The second long-term goal is appropriate for the subsite
because EPA has determined that public health is threatened by
contamination present in the ground water and surface water at
*
the subsite. The feasibility study for the ground water and
surface water remediation at the Galena subsite provides a health
assessment on the basis of the "no action" alternative for
remediation at the Galena subsite. This health assessment
demonstrates the threat of chronic health effects on the exposed
population due to the contamination in the ground water and
surface water at the Galena subsite. The risks are based on
exposure to the contaminants through ingestion of the ground
water and incidential ingestion and absorption through the skin
during swimming activities. The data and conclusions of the RI
and the feasibility study for the Galena subsite support EPA's
decision to evaluate remedial alternatives for achievement of the
protection of human health from the contamination in the ground
water/surface water at the subsite. The health assessment also
showed an additional potential chronic health effect due to
ingestion of the contaminants in the mine wastes.
The third and fourth long-term goals are appropriate because
EPA has determined in accordance with Section 121 (d) of CERCLA,
42 USC Section 9621 (d), that the stated standards for cleanup at
the subsite are applicable or relevant and appropriate. This
determination is based on: (1) the current and potential uses for
-------
11
the ground water, which includes water for both drinking and
agricultural purposes; and (2) the protection of aquatic life and
human health from exposure to the surface water contaminants.
Additional explanation as to the appropriateness of these goals
is found in the aforementioned comments and responses.
As shown, the long-term goals are based on the requirements
of CERCLA and are reasonable for the subsite. These goals are
not inappropriate nor arbitrary and capricious. These goals have
been developed in light of the cleanup standards of Section 121
(d) of CERCLA, 42 USC 9621 (d), and are well within the scope of
CERCLA.
5. Comment: The commenters believe the short-term goals
are inappropriate, arbitrary and capricious, and outside the
scope of CERCLA because they are vague and do not meet ARARs.
Response; The short-term goals were developed during the
feasibility studies for remediation of the Galena subsite. In
the OUFS, EPA determined that certain long-term goals for the
ground water and surface water remediation are technically
impracticable, i.e., the goals of meeting KALs in the ground
water and AWQCs in the surface water. Yet, EPA and KDHE
scientists and engineers also determined that by controlling the
source of the contamination and the hydrology, various degrees of
contaminant reduction could be achieved over a period of time by
a gradual flushing of the ground water and surface water systems.
Although EPA does not have data demonstrating the length of time
required before this gradual flushing would clean the ground
-------
12
water and surface water system to meet the KALs and AWQCs, the
theory is based on sound hydrogeologic principles and best
engineering judgment. The EPA, therefore, believes the short-
term goals are rational, appropriate and based on sound
reasoning.
The short-term and long-term goals were determined to be
appropriate by following EPA's decision-making procedures, which
include: development of the goals by the EPA Remedial Project
Manager, KDHE staff and technical consultants, then review of
these goals by EPA Regional Counsel and EPA and KDHE management.
The EPA management decides, on the basis of scientific and legal
advise, the appropriateness of the goals for the site conditions.
In this case, these short-term goals and the previously described
long-term goals were determined to be appropriate. The
commenters1 suggestion that such goals are arbitrary and
capricious is without merit and directly contrary to the sound
reasoning and decision-making procedures utilized in developing
and determining the long-term and short-term goals.
The same commenters suggest that the short-term goals are
outside the scope of CERCLA and reference Section 104(a)(3)(A) of
CERCLA, 42 USC §9604(a)(3)(A), which states that:
"The President shall not provide for a removal or remedial
action under this section in response to a release or
threat of release -
(A) of a naturally occurring substance in its unaltered
form or altered solely through naturally occurring
processes or phenomena, from a location where it is
naturally found;..."
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13
As discussed previously in this responsiveness summary,
the selected remedial action will remediate the ground water and
surface water systems within the Galena subsite which are
contaminated as a direct result of mining activities. These
mining activities significantly altered the natural hydrogeology
of the subsite so as to cause a release of hazardous substances
within the subsite. The President has authority according to
Section 104 of CERCLA to respond to releases or threatened
releases of hazardous substances at a site. The exception cited
in Section 104(a)(3)(A) of CERCLA is not applicable for the
Galena subsite due to the mining activities which significantly
altered the natural conditions at the subsite, although prior to
the mining activities some naturally occurring hazardous
substances may have been released at the subsite, the mining
activities altered the natural conditions and exacerbated and
accelerated the release of hazardous substances to the ground and
surface waters.
6. Comment; The commenters express concern
that EPA believes the mining activities are the sole cause for
the contamination.
Response; As was acknowledged in the OUFS and
previously in this responsiveness summary, EPA suspects that the
levels of heavy metal contaminants identified in the ground and
surface waters may include contaminants from other sources, such
as unmined ore. The Agency estimates that the surface mine
wastes contribute over 26 percent of the cadmium, zinc and
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14
sulfate contamination in Short Creek. The levels of lead
contamination in Short Creek from the surface mine wastes may be
higher, but are difficult to estimate. Other sources of
contamination include, but may not be limited to, upstream mining
areas, mining wastes found inside mine voids and subsidences and
unmined ore exposed to oxygenated water within old mining tunnels
and rooms.
7. Comment; The commenters state that EPA failed to
consider that the mining activities have removed a large amount
of mineralized naturally occurring materials.'
Response; The EPA is conducting a response at the site
based on the release or threat of release of contaminants
presently found at the site.
8. Comment; The commenters thought EPA should qualify
pre-mining conditions and base the project goals on the findings.
They cite a letter from KDHE where KDHE also suggested defining
background conditions.
Response; The EPA considered investigating the premining
background condition, but did not pursue it because such an
investigation is costly, time consuming and yields only
hypothetical results. Instead, EPA and KDHE determined it would
be appropriate to set goals to improve the current conditions
(which present a health threat). The commenters tried to
establish background conditions at the site, but were unable to
do so. Since mining activities commenced in 1876 at the subsite,
no water quality records are available of the pre-mining water
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15
conditions. The commenters concluded in their investigation that
there may have been elevated concentrations of metallic ions in
Short Creek and shallow ground water system in pre-mining time.
A review of the commenters report on background conditions is
provided in the administrative record.
9. Comment; The commenters believe EPA is obligated to
reevaluate its position concerning the effect of mining on water
quality and EPA's fundamental approach to the goals, objectives
and targets for any remedial actions at the subsite or site.
Response: As expressed earlier,in this responsiveness
summary, EPA's decision to proceed with remedial action is based
on the need to protect human health and the environment and the
release or threatened release of hazardous substances at this
subsite. The goals, objectives and targets are reasonable for
the subsite and site.
10. Comment; The commenters disagreed with the approach
used in the public health assessment in the feasibility study
report.
Response; The public health assessment was conducted for
the no-action alternative at the site using the methodology
established in the EPA guidance documents, the Superfund Public
Health Evaluation Manual and the Superfund Exposure Assessment
Manual. The EPA methods require evaluation of the worst case
exposure situations. The commenters do not believe worst case
scenarios should be evaluated. The commenters indicate that all
V
the individual sources of contaminants (i.e., ore, mines,
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16
smelter, municipal sewage treatment plants, etc.) should have
been evaluated separately. The EPA's evaluation is based on the
exposure to the population today from all sources and assuming no
corrective action will be taken. The EPA believes this is the
most appropriate approach to qualify the risks to the public at
the site since this is the true exposure to the public. The
commenters disagreed with the statistical methods employed by the
risk assessment, although these are the standard methods used in
EPA risk assessments.
11. Comment; The commenters point out as a flaw that the
ground water/surface water operable unit feasibility study (OUFS)
was developed with the assumption that a water system would be
implemented, but that the risk assessment included ingestion of
contaminated ground water.
Response; The EPA sees no flaw in this approach. The
alternatives evaluated in the ground water/surface water OUFS did
not include remedial action to address the ingestion of ground
water. The alternative water supply OUFS has completed an
assessment of that problem. That exposure route was included in
the public health assessment to show that it is an exposure
pathway that must be addressed. In addition, some residents of
the subsite may continue to use private shallow drinking water
wells even after the alternative water system is established.
12. Comment; The commenters suggest that the Alternative
Water Supply (AWS) Record of Decision (ROD) should be reopened
because the estimated contaminant intakes calculated for the
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17
ground water/surface water (GW/SW) OUFS are different from the
AWS.
Response; The intake numbers expressed in the AWS OUFS and
GW/SW OUFS are different. As EPA evaluated the data following
the .completion of the AWS OUFS, it realized there would be some
minor revisions. The EPA was aware of the changes prior to
signing the December 21, 1987, ROD and did not believe it made
any significant difference in the decision. As shown by the
public health assessment in the GW/SW OUFS, the concentrations of
metals in the ground water do pose a significant public health
risk. The Agency has no reason to reopen the AWS ROD.
13. Comment; The commenters state that it is inappropriate
to use maximum contaminant concentrations as plausible maximum
exposures.
Response; These procedures and techniques have been
approved and are commonly used by EPA. As stated in the GW/SW
OUFS report, the exposure assessment used the maximum values as a
screening tool and based the exposures on the mean concentrations
when maximum concentrations exceeded health-based standards. For
example, exposures based on both maximum and mean concentrations
were calculated for ground water ingestion because Direct
Intake/Reference Dose (DI/RfD) ratio exceeded unity for six out
of eleven metals for the 10-kg child scenario using maximum
concentrations. Since these measured data are from private wells
in the shallow aquifer, it is appropriate to classify them as
"plausible maximum exposures."
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For soils and mine wastes, the samples were collected
in the field by compositing several subsamples within
the defined sampling location. Therefore, the maximum
concentration a metal from the composite sample can be
considered a valid "plausible maximum exposure."
Further, EPA guidelines call for exposures to be based
on arithmetic averages and maximum values (page 3-5-4
Superfund Exposure Assessment Manual).
14. Comment; The comments questioned the statistical
treatment of the ground water data in the public health
assessment (PHA). The commenters state that the PHA report does
not indicate, whether all the wells tap the same aquifer. They
state this since the maximum concentrations of several metals
exceed the average values by more than a factor of four, thus the
commenters say it indicates that values come from underlying
statistical distributions with long right tails. They state that
it is misleading and inappropriate to summarize such variables
with the arithmetic mean and maximum values.
Response; The 1988 OUFS text clearly indicates that the 123
wells sampled during the RI are private residential wells drawing
water from the shallow aquifer. OUFS Appendices provide
available data on well depth, but in many cases well depth and/or
screen interval depth were based on owners' recollections and
could not be ^documented due to observed well construction or lack
of permission from the well owner to access the well and measure
the depth. The physical characteristics of the shallow aquifer
are described in detail in the OUFS.
Again, EPA standard protocols call for exposures based on
mean and maximum concentrations. There is no basis for believing
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that contaminant concentrations are distributed lognormally at
Galena.
15. Comment; The commenters state that the Public Health
Assessment report supplies no justification for use of the lower
MCL for hexavalent chromium. They believe the chromium at the
site is trivalent chromium which is less toxic.
Response: The analytical data are reported as total
chromium and the MCL is for total chromium.
16. Comment: The commenters state that while it is a
standard assumption in public health risk assessments to assume a
70-kg adult ingests two liters and a 10-kg child ingests one
liter of water a day, the report does not state the assumption
used to evaluate the ingestion of water by a 35-kg child.
Response; In this report, quantitative risk assessments for
ingestion of water were calculated for the 10-kg child and the
70-kg adult. The 35-kg child was used for swimming exposures
only. The risk associated with the daily consumption of water by
the 35-kg child was assumed to be somewhere intermediate of the
10-kg child and the 70-kg adult, and was not specifically
quantified.
17. Commentt The commenters state that the use of the
maximum values in the Public Health Assessment, without any
information about the underlying statistical distributions or
even the arithmetic average, is inappropriate and likely
misleading. They state that often concentration measurements in
natural waters follow a lognormal distribution for which the use
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of a maximum value as the summary statistic is highly misleading.
The effects that are of primary interest in this risk assessment
are chronic, i.e., resulting from long-term exposure. The
appropriate statistic to use, in the commenters1 opinion, is one
that represents the level of exposure that would be expected on a
long-term basis.
Response: As stated previously in this responsiveness
summary, maximum concentrations are useful as a screening tool.
That is how they were used. These risks from both surface water
pathways indicated no DI/RfD exceedances for any metal based on
maximum concentrations. Therefore, risks based on mean
concentrations were not calculated.
18. Comment; The commenters state that the Public Health
Assessment report has not established that children swim in any
of the water bodies and that it assumes implicitly that the 35-kg
child swims every day of the year. They stated that these
assumptions are not realistic. They say that the overly
conservative assumption in this report overstates the estimated
exposure by a factor of five or more above the conservative
assumptions normally used to gauge these possible exposures.
They state that EPA's Superfund Exposure Assessment Manual (US
EPA 1986) states that: "The local recreation department may have
detailed data quantifying the duration and frequency of water use
for swimming. When such locale-specific data are not available,
the following national averaged figures, based on data from the
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Bureau of Outdoor Recreation (cite) can be applied:
Frequency of exposure = 7 days/year
Duration of exposure = 2.6 hours/day"
Response: The Galena Subsite Remedial Investigation
Report (EPA, 1986) documents the water bodies that are popular
swimming areas, mainly the "Blue Hole," large mine subsidence
near the high school, and Shoal Creek at Schermerhorn Park. The
remedial investigation report further states, "all surface waters
are or could be used for swimming and wading." The EPA agrees
with the commenters1 proposed duration and frequency adjustments.
However, the overly conservative scenario used in the OUFS
indicates no DI/RfD exceedances, so more realistic scenarios were
not developed. Adjustments to the duration and frequency for
swimming would not affect the final conclusion of the risk
assessment. The commenters also have other comments on the
methodology used in evaluating the risk due to surface water
contact. Since swimming and ingestion of water during swimming
were not shown to be a risk, the comments on the conservative
approach employed in the health assessment do not change the
conclusions of the assessment.
19. Comment; The commenters state that neither the
remedial investigation nor the OUFS has made any attempt to
measure "representative" concentrations of metals in soils near
Galena. The commenters believe it is inappropriate to define
worse case situations and that it may overstate otherwise
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"representative" or "average" analyses by as much as several
orders of magnitude.
Response: The EPA is not only concerned with the average
exposure, but must also address the greatest exposure. Soil
samples collected during the Phase I RI were from the area
downwind of the former smelter along Short Creek as documented by
earlier studies. The sampling effort was designed to determine
metals concentrations at several locations along the path of
prevailing winds, with increasing distance from the smelter.
Each location was sampled using a five-point composite technique,
at two depths. These samples are representative of soil
conditions downwind of the former smelter. Quantitative risks
based on these samples apply only to this area, and the OUFS does
not imply that these risks should apply to other areas such as
residential Galena. Several occupied farmhouses are located in
this area downwind of the smelter. Residents in this area are
exposed to the stated risks.
Mine waste sampling during 1987 was designed to obtain
samples representing the metals concentrations in mine waste
piles, excluding chat; and again there was no intent, actual or
implied, to state that risks based on these data were applicable
to anything else except these mine waste areas. However, mine
waste piles occur in or near the yards of many houses in Galena.
Mine wastes also have been used throughout the area for fill
material, roads and residential driveways. Therefore, the
exposure scenario presented is a "plausible maximum exposure."
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Furthermore, residents use the mine waste areas for recreation
activities such as riding dirt bikes.
20. Comment; The commenters state that it is unlikely and
inappropriate to model a 1'0-kg child (say, ages 1 through 3
years) as eating one gram of soil each and every day, especially
dirt from the most contaminated waste piles and soils downwind of
the former smelter. They went on to say parents and caretakers
of children in this age range rarely let them play in industrial
waste sites. Second, rain, snow, ice and frozen soils would
limit the ingestion of soils on many days of the year, even if
children happened to play in the most contaminated areas. Third,
recent review articles suggest that one gram per.day for the
ingestion of soils by children is a gross exaggeration. More
specifically, LaGoy (1987), in a major and authoritative review,
estimates that a 10-kg child ingests an average of 50 mg of soil
per day and a maximum of 250 mg of soil per day from all sources,
not just from heavily contaminated sites. Similarly, Paustenbach
(1987) states, "When all this published information on soil
ingestion is considered, the data indicate that a consensus
estimate for soil ingestion by children (age 1.5 to 3.5 years or
ages 2 to 4) is about 100 mg/day. This figure was used by the
EPA in its risk assessment and in the EPA Superfund Health
Assessment Manual." Thus, the value of one gram/day (1,000
mg/day) assumed in this report overstates other authoritative and
conservative estimates by a factor of 10 or 20 on mass alone.
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Response; The scenario used in the risk assessment is
realistic because, 1) several of the mining and associated waste
areas are in very close proximity to residential areas, 2) there
are no restrictions on accessing the waste areas and 3). residents
have been known to use mine waste as sources of fill or gravel.
The Superfund Exposure Assessment Manual states that the
frequency of occurrence should be determined on a case-by-case
basis. There were no data available to adjust the frequency
based on weather conditions. The weather adjustment
interpretation has been left to the reader of the document.
The Superfund Public Health Evaluation Manual which was used
at the time the risk assessment was made, states that soil
ingestion rates for children age two to six range from 0.1 to 5
grams per day. Further, the Superfund Exposure Assessment Manual
which indicates the ingestion rate may vary from 0.1 to 10 grams
per day. Therefore, the ingestion rate is within this range and
was considered appropriate at the time. Recent guidance by EPA
has established soil ingestion rates to be used in future program
risk assessments. The ingestion rate for children who are one
year through six years of age is 0.2 gms/day and for adults is
0.1 gms/day.
21. Comment: The commenters have similar comments about the
ingestion of soils by adults. They believe it is unlikely and
inappropriate to assume an adult would eat 0.1 gram of soil a
day.
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Response; The Superfund Exposure Assessment Manual and
recent EPA interim guidance indicates a value of 0.1 gram per day
should be used as an overall soil ingestion value for adults.
Since there are houses within and immediately adjacent to the
contaminated areas, the adults in question will normally be
exposed to these contaminants on a daily basis.
22. Comment; The couunenters disagreed with EPA's use of
maximum metal concentrations in the assessment.
Response: The EPA's standard procedures require for
exposure assessments to be based on maximum and mean
concentrations as was done in the OUFS.
23. Comment; The commenters state that it has'not been
established that people catch and eat fish from the local waters.
Response; The Galena Subsite Remedial Investigation and
other scientific literature on the Spring River document the fish
populations and fishing activities in the area. The local
fishery in Empire Lake and the Spring River above and below the
lake would provide the quantity of fish for this scenario
(Branson, Triplett and Hartmann, 1970). The conservative
scenario in the OUFS indicated that this exposure route
represented a nominal risk compared to ingestion of ground water
and mine wastes and, therefore, was not refined further.
24. Comment; The commenters believe that the risk
assessment overestimated the amount of fish a child would eat.
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Response; The EPA agrees with the commenters. However,
exposure due to ingestion of fish represents a negligible
contribution to the total daily intake presented in Table 3-13 of
the OUFS report. For children, using two significant digits for
the total daily intake, the fish exposure does not contribute at
all. Therefore, reducing the fish intake by another 20 percent
would have no effect on the final conclusion of metallic
contaminant total intake for children.
25. Comment; The commenters state that swimming and eating
contaminated fish are not primary pathways for exposure because
the other pathways are "larger" and because the analyses of the
other pathways suffer from exaggerated assumptions.
Response; The OUFS report states exactly this point.
Swimming and eating local fish are nominal exposure pathways
compared to drinking ground water from private residential wells
and incidental ingestion of mine wastes. There is no basis for
the statement that ground water and mine waste ingestion
scenarios are exaggerated.
26. Comment; The commenters state it is not clear that the
Congress or the EPA intends that the MCLs and MCLGs developed
under the federal Safe Drinking Water Act are to be used as
"ARARs" for ground water in mining districts, precisely because
the concentrations of some or many metallic ions may exceed the
MCLs or MCLGs at present and may have done so for eons.
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Response; It is EPA's policy that MCLs are ARARs for ground
water at Superfund sites that is currently used as a drinking
water source or could possibly be used as a drinking water
source. Such policy is in accordance with cleanup standards
found in Section 121(d) of CERCLA, 42 U.S.C. §9621(d).
27. Comment: The commenters question the source of the
cancer potency factors used in the assessment.
Response; The Integrated Risk Information System (IRIS),
the most authoritative source for cancer potency factors, was
used in the assessment when values were available. Arsenic was
the only carcinogen evaluated. The most recent cancer potency
established by EPA's Risk Assessment Forum was used.
28. Comment; The commenters believe it is inappropriate to
assess all the private drinking water wells on the maximum
concentration for each compound. They state that concentrations
of metals dissolved in ground water commonly follow a lognormal
statistical distribution.
Response: The comparison between water quality of private
wells and MCLs was based on maximum concentrations of metals
observed in well waters. Maximum concentrations were used
because this was a screening process, and because many wells were
sampled only once. The table in the OUFS Report (Table 2-5) does
report the number of wells exceeding each individual criterion
and the number of wells that exceed more than one criterion
simultaneously. There is no basis for the assumption that the
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data are distributed lognormally.
29. Comment: The commenters state that no attempt was made
by EPA to distinguish between natural background conditions and
man-made conditions of various sources.
Responses; The EPA did not define background conditions nor
distinguish the risks based on the natural conditions and mining
conditions. These sources are considered in the assessment, but
are not distinguished because the public is exposed to both these
sources. The commenters are concerned that EPA is remedying
natural background conditions. This is not the case. The EPA is
remedying contamination caused by human activities which remain a
threat in its present condition to the public health and welfare.
30. Comment; The commenters question the plausibility of
the exposure scenarios in the OUFS. As an example, they question
whether the scenario of ingestion of soils by children is
plausible.
Response; Mine waste areas are contiguous with residential
neighborhoods in several different areas of Galena. Furthermore,
mine waste materials have been transported into residential areas
and used for numerous purposes, such as private driveways, so it
is a common surface material throughout the city. Fugitive dust,
movement of people and pets, and weather conditions transport
that material into the houses in several Galena neighborhoods.
Therefore, Galena residents and the residents in the area
downwind of the former smelter, including young children, are
directly exposed to these mine waste materials and contaminated
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soils every day. The scenario used in the OUFS is conservative,
but not exaggerated.
31. Comment; The commenters discuss discharges from a
facility offsite of the Cherokee County site. They also state
that there are other sources of contaminants. They believe such
releases should be qualified.
Response; The Galena subsite Remedial Investigation and OUFS
reports both acknowledge that there are numerous sources of
mining-related and nonmining-related contaminants to the surface
waters in the Spring River watershed. The sampling programs
included upstream control stations to document the water quality
coming into the site or subsite, and downstream monitoring
stations to document the water quality leaving the area. These
other sources were considered qualitatively and quantitatively on
a limited basis..
Because of the regional nature of the surface water quality
program, it would be very costly to attempt to quantify each
source of contamination and technically impossible to separately
assess the environmental impact of each. There is sufficient
data in the EPA reports for the reader to make a comparative
assessment of the contributions from the potential sources of
metals and nutrients. The OUFS and supporting documents clearly
show that a considerable increase in metals loading occurs in
Short Creek within the subsite, which is not related to the
offsite fertilizer plant.
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Permitted discharges are not addressed in this operable unit
remedial action. The permitted release from the offsite
fertilizer plant contains different contaminants from the
contaminants that are the subject of this remedial action. The
offsite fertilizer plant is located on a former mining site and,
•
therefore, the contaminants that migrate from this site are
similar to those at the Galena subsite. Evaluations in the OUFS
considered the offsite-upstream source of contamination, but the
selected remedy does not include remediation of that area. The
Agency plans to conduct investigations at the fertilizer plant in
the future. The RI and OUFS for the Galena subsite indicate that
most of the subsite contamination is from sources within the
subsite.
32. Comment; The commenters are concerned that the
environmental risk assessment does not take into account natural
background conditions.
Response; It is not possible to define natural background
conditions. The risk assessment evaluates the current situation
where hazardous substances have been released or where a release
is threatened. The selected remedial action will remediate the
areas impacted by mining activities to mitigate the exposure
risks to the public health and welfare and the environment.
33. Comment: The commenters do not believe the reduced
diversity of macroinvertebrates in Spring River are the result of
elevated concentration of metals.
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Response; The assessment of macroinvertebrate populations
in the Spring River was based on existing scientific literature
(KDHE 1980 and 1984; Branson 1966) since there were no site-
specific studies of benthic biota conducted. Data from the
macroinvertebrate studies were also compared to water quality
data in the literature and data collected during the remedial
investigation.
The KDHE (1980) water quality and biological survey of the
Spring River and its tributarires noted low diversity and absence
of several pollution-sensitive benthic groups in the lower
reaches of the Spring River, and KDHE (1980) made the following
statements.
The biota in the lower reaches of the Spring River which
receives mine drainage from several polluted tributaries
continues to be stressed.
Heavy metals in solution constitute a very serious form
of pollution because they are very stable compounds not
readily removed by oxidation, precipitation or other
natural process. (This is especially true of zinc.)
The general depletion at the downstream stations is
attributed to continued exposure to lead-zinc mine
drainage.
It is postulated that zinc toxicity was probably
indirectly responsible for the restricted taxa due to
limited variety of food available.
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The drastic reduction in taxa, especially the mayflies,
is attributed to chronic exposure to heavy metals.
A similar biological depletion of the lead-zinc pollution
sensitive MCOL group was noted in the benthic samples
from Center Creek during 1964-65 pollution survey by
Missouri. (Biological Data - 1973. James, Elk and
Spring Basin Water Quality Report. Missouri Clean Water
Commission, Jefferson City, Missouri. 1974.).pm
Scientific investigators will agree that there are several
water quality parameters (such as ammonia, nutrients, organics)
and physical factors (such as flow and substrate type) operating
on the benthic macroinvertebrate populations in the Spring River,
in addition to metals concentrations. Most would also agree that
increasing nutrients and organic pollution along the Spring River
probably cause some reduction of benthic diversity. However, the
nine-year plus biomonitoring data base on the Spring River
indicates a consistent reduction in benthic macroinvertebrates in
the Kansas portion of the river and a consistent and
corresponding increase in metals concentrations. Metal
concentrations almost certainly play a role in reduced benthic
diversity, especially since some metals are almost always above
concentrations known to have a chronic effect on aquatic biota.
34. Comment; The commenters state that the sources of
contaminants are not defined; therefore, the importance of the
different sources of biological stress to the waterways cannot be
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determined.
Response; The water quality data at numerous locations
along Short Creek and at tributaries near their confluence with
Short Creek, were presented in the remedial investigation and
OUFS. This included stations both above and below the fertilizer
plant in Missouri. The EPA reports present sufficient data to
make a comparative assessment of the contributions from the
potential sources of metals and nutrients. The Galena subsite
OUFS and supporting documents clearly show that there is a
considerable increase in metals loading in Short Creek within the
subsite that is not related to the fertilizer plant in Missouri.
(Refer to Table 3-30 of the OUFS).
A "Use Attainability" type analysis would be required to
quantitatively assess the separate impacts; and at this time,
there are no scientific methods that will allow a complete
quantification of synergistic and antagonistic affects. The data
adequately illustrate which tributaries to Short Creek are the
major sources of metals contaminants and to document which
segments of the creek experience the greatest changes in metals
concentrations.
35. Comment; The commenters made several comments on the
milling operation as presented in the 1988 OUFS and 1988 Proposed
Plan. The volumes of the surface mine wastes, the treatability
of the material and the costs were questioned.
Response: As the result of these comments, the EPA
collected additional samples of the surface mine waste rock and
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treatability studies have been conducted. Based on these
studies, the estimated costs for the act of treating the wastes
were refined. In addition, an OUFS Supplement and 1989 Proposed
Plan have been prepared which present revised remedial
alternatives.
36. Comment; The commenters state that EPA's
characterization of the waste piles conducted prior to the
release of the 1988 Proposed Plan concentrated exclusively on the
piles of broken rock and ignored the chat which constitutes 58
percent of the surface wastes. They state that their preliminary
sampling indicates that the chat has much lower lead content.
Response; The EPA's waste characterization conducted prior
to the release of the 1988 Proposed Plan concentrated on the
material that it thought could be fed into a milling circuit with
any possibility of reducing the metal content. The chat at that
time was suspected to be low in lead. Therefore chat was not
considered in the characterization study; conventional milling
operations were not considered applicable. Because of these and
other comments received, the EPA conducted analytical tests on
the chat and found that it is not consistently low in lead. Some
of the chat piles will need to be processed as is recognized in
the OUFS Supplement and the selected remedy.
37. Comment; The commenters state that the waste rock
sampling plan prepared and implemented prior to release of the
1988 Proposed Plan was in error because only surface samples were
collected except for two locations. They do not believe the
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overall waste materials present have been realistically or
properly defined.
Response; The purpose of the sampling conducted prior to
1988 was to characterize the waste piles that could be processed.
This goal was achieved. Analysis of split samples conducted by
the commenter showed that the waste rock can be processed to
remove a large percentage of the metal content.
Additional samples were collected during the week of June 6,
1988, for the bench-scale laboratory treatability tests. A
backhoe was used to dig into several waste piles to collect
deeper samples of the mine wastes for the treatability tests. In
addition, many samples collected prior to and as preparation for
the pilot leach test were from areas deep within chat and waste
rock piles.
38. Comment; The commenters state that EPA divided the
samples collected prior to 1988 by cone and quartering, which
they do not believe is a reliable method for coarse material of a
heterogeneous nature. They state that all the handling of the
samples, including cone and quartering, transporting and
laboratory size reduction offer the potential for gravity
segregation of the heavy minerals.
Response: The EPA disagrees, coarse materials have a less
likelihood of segregating and during the process of size
reduction blending would occur. Also, these samples are an
estimate of a very large mass of heterogeneous material. Any
small deviation from the exact value would still fall into an
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acceptable estimate range for the waste piles.
39. Comment: The EPA estimated that 283,000 cubic yards of
waste were present within eight areas delineated for sampling in
the OUFS. Field work carried out by the commenters resulted in
an estimate of 1,279,000 cubic yards of waste rock, chat and
other mine wastes.
Response; The EPA has recognized this volume change in the
OUFS Supplement and will consider it in implementing the selected
remedy. Prior to 1988, the EPA only sampled and evaluated waste
piles that would have a possibility of having their metal content
reduced by conventional milling operations. Waste piles with low
metal values, such as chat, were not taken into the waste pile
volume estimate. The commenters estimated that 488,696 cubic
yards of the 1,279,000 cubic yards are of waste rock, excluding
chat. That is about 2/3 more material than EPA estimated, but
not 450 percent more as the commenters estimated all waste
material. Since the 1988 OUFS was completed, additional
analytical work has shown that some of the chat will need to be
processed; therefore, a revised volume estimate will be
considered in the selected remedy.
40. Comment; The commenters suggest that EPA erred in
calculating tonnage prior to 1988 from the waste volume
estimates. The EPA has stated that 327,000 tons are present,
indicating that a value of 1.15 tons per cubic yard was used.
The commenters state that a standard earthmoving reference such
as the "Caterpillar Handbook" indicated a value of at least 1.35
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tons per cubic yard would be appropriate.
Response; A value of 1.35 tons per cubic yard is a good
value for "in place" rock. The value was reduced downwards to
1.15 to take into account the broken nature of the material in
the piles.
41. Comment; The commenters state that the EP toxicity
type tests are a non-flow related, mass leach test that does not
simulate natural conditions, because it assumes a steady state
and does not take into account intensity and duration of rain
fall events, drainage dynamics and the highly permeable nature of
the surface wastes.
Response; The EP toxicity test, along with the other tests
such as the water and acid shake tests, provide only an estimate
of leach conditions. The EP toxicity test provide a worst case
in a landfill scenario, whereas the water and acid shake tests
provide a best and worst case scenario where acid mine drainage
is involved.
42. Comment; The EPA's 1988 proposed plan is a modification
of the Alternative 3 from the 1988 OUFS described in the 1988
proposed plan. The commenters state that the effectiveness of
the proposed plan had not been modeled or evaluated.
Response; The EPA evaluated the effectiveness of the 1988
proposed plan prior to considering it as the preferred remedy in
1988. The 1988 proposed plan was estimated to reduce metal
loadings by approximately 40 percent. It was estimated to reduce
the loadings the same as the 1988 OUFS, Alternative 5. As part
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38
of the development of the selected remedy, Alternative 2, which
is an updated version of the 1988 preferred remedy, was modelled
by computer (as the other alternatives were in the OUFS) and was
estimated to reduce metal loadings by 28 to 32 percent.
43. Comment: The commenters indicate that the concentrate
from the milling process is not marketable or if there are
intermediate by-products of the process which cannot be marketed,
disposal as hazardous wastes could be required, causing a
significant additional expense.
Response; In 1988 the EPA considered the concentrate
generated from the milling/flotation process to be marketable.
Additional tests conducted following the completion-of -the 1988
OUFS, as presented in the OUFS Supplement, indicate that the
concentrate would be marketable.
44. Comment: The commenters state that EPA1s 1988 proposed
remedial action will have little effect on the metal levels
available to enter the ground water and surface water. They state
that this is because only between 40 and 70 percent of the lead
is likely to be recovered by the proposed milling process, with
similar low recoveries of other metals.
Response; The 1988 milling process proposed in the 1988
remedy projected the reduction of cadmium, lead and zinc levels
by over 80 percent. Subsequent bench-scale tests were performed
to identify the appropriate milling processes. Through these
studies, EPA has determined that metals levels in the surface
mine wastes would be substantially reduced. The EPA, therefore,
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39
disagrees with this comment.
45. Comment; The commenters estimate the cost to build a
mineral processing facility at between 6 and 9 million dollars
compared to EPA's estimate of $610,000. The commenters estimate
operating cost to be between $10.53 and $13.38 per ton compared
to EPA's estimate of $4 per ton.
Response; The EPA's plan outlined in the 1988 OUFS
considered that a small, bare bones plant, that can be assembled
onsite, would be shipped to the site on skids. Only the ball
mill was considered to need a permanent foundation. The EPA has
reestimated the costs in the OUFS Supplement following the
treatability studies and other additional testing and
consideration of information submitted by the commenters. These
revised cost figures are provided in the OUFS Supplement.
46. Comment; The EPA estimates the materials handling costs
to be $49,000 whereas the commenters estimate the cost to be $4.4
million.
Response; The conunenter is referring to haulage costs for
Alternative 2 which were estimated based on local milling of the
mine wastes. These costs were underestimated in the OUFS.
Revised analysis included increasing the volume of mine wastes to
be hauled and the use of a central milling location. Based on
this reanalysis, the revised cost is approximately $800,000 (see
OUFS Supplement, Appendix F, page 28). This cost, while more
than the original estimate, is much less than the 4.4 million
dollars advanced by the commenter.
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47. Comment; The commenters state that under the natural
geologic process, metallic ions are provided to the shallow
ground water system and surface water until these materials are
totally oxidized and the contained ions are flushed from the
area. They state that under existing conditions, it would take .
more than 1,000 years for the residual sulfide mineralization to
be flushed from the system. The comments stated that the EPA's
1988 proposed plan would extend the time required for flushing.
Response: The EPA has not estimated how long it will take
for the system to be flushed naturally. The EPA's selected
remedy as well as the 1988 proposed plan would be expected to
speed up the natural cleanup process. The main purpose of the
action will be to protect the public health and reduce the
environmental threats.
48. Comment; The commenters suggest that the no-action
alternative with appropriate administrative controls could
provide as much protection to human health and the environment as
provided by the 1988 and 1989 proposed plans and at significantly
less cost.
Response; The EPA did consider administrative controls
such as fencing and posting to protect the public health, but did
not consider these to be effective. These type of controls are
not permanent, they only offer temporary control at best. At
least one of the areas was fenced off, but tresspassers have
destroyed the fence. It is difficult to get people to understand
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the potential dangers when the hazards are based on chronic
exposure as opposed to situations where the exposure is immediate
and painful.
C. Comments from PRPs to the Alternative Water Supply OUFS
The PRP specifically requested their comment letters on the
alternative water supply OUFS (letter to Alice C. Fuerst dated
December 10, 1987) and the Site-Wide Supply Inventory Technical
memorandum (letter to Alice C. Fuerst dated February 1, 1988) to
be incorporated by reference into their comments on the ground
water/surface water OUFS. The comments in the former letter were
responded to in the alternative water supply responsiveness
summary dated December 21, 1987.
1. Comment; In the Final Technical Memorandum for the
Site-Wide Water Supply Inventory (November 25, 1987) EPA sampled
private water supply well prior to treatment. The commenters
state that while this practice is acceptable if the purpose of
the investigation is to determine the quality of the shallow
aquifer. They state that it is not proper if the purpose is to
determine if the water is suitable for consumption.
Response; Water samples from private wells were collected
prior to any in-house treatment unit because the primary
objective was to characterize the water quality of the shallow
aquifer. These same samples were also used to assess the
potential health risks associated with using this water resource
because:
a. There was a variety of in-house treatment units ranging
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from simple filters to reverse-osmosis type systems.
Some of these units remove dissolved metals, the
contaminants of concern, and some do not.
b. The effectiveness of in-house units is highly dependent
on timely servicing and maintaining the unit in good
condition. Therefore, the effectiveness was expected to
be quite variable and EPA or state agencies have no way
to ensure their effectiveness.
c. Most in-house treatment units in the area were installed
by EPA as a temporary measure to reduce the metals
concentrations in water being used at selected private
residences while EPA continued to work towards a
permanent solution.
d. Ground water sources are usually not treated prior to
use, except for chlorination of public systems.
Therefore, the public health assessment was based on the
assumption that most shallow wells had no treatment
units (a fact based on RI surveys), new wells could be
drilled at any time without adding treatment units, and
existing treatment units could become ineffective or be
removed at some future date.
2. Comment; The commenters believe the references to non-
enforceable, non-regulatory guidelines and criteria (i.e.,
secondary MCLs, MCLGs and Clean Water Act criteria) are
inappropriate because they are not ARARs for the
Alternative Water Supply OUFS.
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Response; One objective of the Sitewide Water Supply
Inventory was to compare the water quality of the shallow aquifer
to drinking water standards, maximum contaminant level (MCL)
goals, and human health criteria based on the Clean Water Act.
This objective was stated in the work plan and is consistent with
the National Contingency Plan (NCP). The purpose of this
Technical Memorandum was to provide an overall assessment of the
ground water quality and comparison to a variety of criteria,
standards and advisories is one recommended approach. This
overall assessment provides a data base for the subsequent
feasibility study that specifically addresses the ARARs.
The Comprehensive Environmental Response, Compensation and
Liability Act (CERCLA) states that response actions should attain
or exceed ARARs. CERCLA further states that other federal and
state standards, requirements, criteria or limitations considered
in fashioning CERCLA remedies and, if pertinent, should be used.
Therefore, the Sitewide Water Supply Technical Memorandum would
be incomplete if it did not address these other criteria.
For ground water actions, it is EPA's policy that the untreated
ground water must meet MCLs if it could be a drinking water
source. It is not an ARAR in the Alternative Water Supply action
for the shallow aquifer to meet MCLs because the shallow aquifer
is not being addressed by that action (i.e., the Roubidoux
aquifer is the source). MCLs are ARARs in the shallow ground
water in the ground water/surface remediation. The Alternative
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Water Supply OUFS referenced secondary MCLs, MCLGs and Clean
Water Act criteria because they are open criteria "to be
considered" in making decisions.
3. Comment: The commenters state that it is inappropriate
to use detection limits that are higher than the drinking water
standard when the primary objective of the investigation is to
verify compliance.
Response; First, the purpose of the investigation was not to
verify compliance with the standards because compliance infers a
requirement. Private water wells are not regulated by Kansas nor
EPA. Second, EPA has standard detection levels it uses across
the nation in most cases. In special cases, at extra expense,
EPA does modify the detection limits for specific sampling
events. In all cases except for selenium, the standard detection
limit is at or below the MCL.
4. Comment; The commenters state that the EPA's data
included both quantitative and qualitative values. There was no
differentation made between actual quantitative and estimated
values.
Response; The EPA conducts a very extensive quality
assurance evaluation of its data. If a sample is not handled
completely properly or if there is some other question about the
data, they are coded as estimated values. In reality, if the
data are not correct, it is actually being estimated lower than
the true result. The EPA is very confident that the estimated
values are at least as high, but not higher than, the actual
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values. If there is any doubt in this, the data are coded "I"
and no estimates are reported.
A small percentage of the data used to define
standard/criteria exceedances were indeed qualified with "J" or
"M." The "J" qualifier signifies that the value did not meet all
Quality Assured (QA) criteria and must technically be considered
an estimate. The "J" qualifier does not mean that the data are
unusable, but only that the value has a somewhat greater margin
of error than data without a qualifier. Data qualified with a
"J" are usable for the purposes of characterizing ground water
quality.
Data qualified with an "M" are values that are below the
detection limit required by the laboratory's contract with EPA
for the given sample set. These data are above the detection
limit of the instrument and are considered usable data. These
data (with "M" and "J" qualifiers) were used in the Sitewide
Water Supply Technical Memorandum and the AWS OUFS because they
were judged more representative of the actual water quality than
either the detection limit or zero concentration.
Of the 22 wells that were defined as exceeding the Safe
Drinking Water Act MCLs or MCLGs (Tables 7 and 12 of the
Technical Memorandum), 18 exceedances were based on data without
qualifiers. Four wells were defined as having cadmium
exceedances based on data qualified by "J" (Well 95, Sample
BMHB9001; Well 83, Sample BMHB9004; Well 91, Sample BMHB9005;
Well 48, and Sample BMHB9007). Of the four wells with qualified
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exceedances, one (Well 95) was confirmed by two subsequent
samples that did not have qualifiers on the cadmium values (Well
95, Samples CMJB9013 and FMJB9007). The remaining three wells
did not have exceedances in subsequent samples.
Data qualified by "J" were also used in determining
exceedances of the secondary MCL for iron and total dissolved
solids. Data qualified by "M" were used to determine exceedances
of the CWA Health Criteria for nickel.
5. Comment; The commenters questioned the use of first
round sample as the reported value as opposed to using an average
of the two sampling rounds.
Response; The use of first-round sampling data for
exceedance determination in the Sitewide Water Supply Technical
Memorandum (TM) was not arbitrary. Each well was originally
sampled during one of the three sampling activities (BMHB9—24
wells, DMJB—59 wells, J39B9—82 wells). Resampling was
performed only at wells that had exceedances based on the first-
round sample set. The best use of this data set is to allow the
three first-round sample sets to represent point-in-time water
quality estimates. Although temporal variations may have
occurred between sampling activities, using the three sample sets
as a representative group places equal statistical weight on each
well in representing point-in-time ground water quality.
In the AWS OUFS, where average concentrations were reported,
multiple samples taken from a single well were used to calculate
the average concentration for that well. The commenters have
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erroneously assumed only the first sample was used.
Finally, in the AWS OUFS, multiple samples from individual
wells were used to calculate the number of exceedances. In the
OUFS, as in the Sitewide Water Supply Technical Memorandum, only
those samples taken prior to in-house treatment units were used
to calculate exceedances and average concentrations.
6. Comment: Several wells that exhibited "minor"
exceedances in the first sampling had no exceedances in
subsequent samples. The commenters suggested that the probable
explanation for this is analytical error or procedural
variability.
Response; There are several sources of potential error or
data variability that influence the data base used in the project
reports. As suggested by the commenters, variation within
laboratory analytical procedures and field sampling procedures
are two sources of variation. However, temporal variation in
well water quality and the use of more than one analytical
laboratory also introduce some variation. This project was not
designed to compare the magnitude of these or other sources of
variation, and conclusions regarding which were most important
would be highly subjective. The development and implementation
of quality assurance and field operation plans, however,
maintained adequate control of field and laboratory procedures
and ensured that data from samples that did not meet QA/QC
criteria were not used.
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The observation that some wells had remarkably consistent
water quality (cadmium results, Tables 8 and 13), while other
wells had variable water quality suggests that the hydrogeologic
system is complex and that some wells are prone to temporal
variations while others are not.
7. Comment; The commenters state that the use of first-
round sampling results was not consistently applied in
determining exceedances.
Response: In one instance, the use of first-round sampling
data was indeed inconsistently applied to the determination of
exceedances. The second sample from Well 3N was used instead of
the first. This was the only case where a first-round sample did
not have any MCL or MCLG exceedance, but a subsequent sample did.
The well was resampled because the MCLG for lead was closely
approached in the first-round sample. The resampling results
showed total lead above the MCLG. The decision was made to use
the second-round sampling data in this case because there was a
responsibility to flag the well as one having elevated metals.
8. Comment; The commenters indicated that the Sitewide
Water Supply Technical Memorandum states on page 3 that five
wells exceeded the primary MCL for cadmium or chromium as a
result of the 1985 sampling, but Table 12 indicates only four
wells exceeded the standards.
Response; The statement on page 3 of the Technical
Memorandum is from the Phase I RI Report. An assumption made in
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the Phase I RI report was that a water quality result that
equaled a standard/criteria was defined as exceeding the
standard/criteria. The assumption made in the Technical
Memorandum, however, was that a result equal to a standard did
not exceed the standard. As a result of this difference, the 10
ug/1 of cadmium in sample BMHB9005 was defined as exceeding the
primary MCL in the Phase I RI, and not exceeding it in the
Technical Memorandum.
9. Comment; The commenters stated that two cadmium MCL
exceedances were based on first-round data qualified by "J," with
subsequent sampling results that show cadmium below detection.
One of these wells (Well 48, original sample BMHB9007, Table 13)
had three subsequent samples all showing cadmium below detection.
The comments believe this well should be removed from the list of
exceedances.
Response; If the MCL exceedance for Well 48 is not
considered a problem because three subsequent sampling results
were below the detection limit or the MCL, then any exceedance
based on only one sample would be open to question. The EPA
believes there is enough variability in the aquifer to be
concerned about all exceedances. In the AWS OUFS, the data from
all samples taken from each well were used to calculate the
number of exceedances (excluding those samples that represent
posttreatment samples from houses with individual treatment
units).
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10. Comment; The commenters believe that the administrative
record for the Technical Memorandum and the AWS OUFS should be
amended to state that there were no chromium exceedances,
because, in their opinion, EPA used an overly conservative
assumption.
Response: As stated by the commenters, chromium can be
present in water in several form; however, the primary MCL and
MCLG are for total chromium, not just the hexavalent chromium.
The Sitewide Water Supply Technical Memorandum and the
alternative water supply OUFS compared total chromium values to
two criteria, the primary MCL of 50 ug/1 and a proposed MCL goal
of 120 ug/1 that is based on total chromium. These comparisons
were clearly stated in the reports.
The EPA considered the fact that there were no exceedances
of the proposed MCLG and only one exceedance of the primary MCL
(with the conservative assumption) during their selection of the
proposed remedy for the alternative water supply.- -
11. Comment; The commenters stated that only eight (not
10) of the 72 wells sampled in the Galena subsite in 1985 and
1986 had "real" exceedances of the primary MCLs. Seven of these
were "minor exceedances" with no likely health significance. The
remaining well (Well 108, sample DMJB9036 with 170 ug/1 cadmium)
appears to be removed geographically and hydraulically from
mining.
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Response; As stated previously, the EPA does not agree with
the commenters opinion of removing any of the wells with
exceedance. The commenters1 contention that seven of these
exceedances have no likely health significance is without
justification because several other factors other than just the
MCL should be considered before assessing potential health risks.
For example, the primary MCL considers the economic aspects of
treatment as well as human health risks and the proposed MCL
goals for both cadmium and lead are lower than the currently
existing MCLs. Several other factors should be considered before
drawing the conclusion that a small exceedance of an MCL does not
represent a health significance. Well No. 108 (original sample
DMJB9036) is located directly downgradient of mining based on the
piezometric contours presented on Figure 4-3 in the Phase I RI
and based on the locations of underground mines and shafts.
12. Comment; The commenters have drawn the assumption that
the first priority areas were designated as "first" because they
would have a higher incidence of contamination due to mining
activity.
Response; The EPA, in designating first and second priority
areas for the Sitewide Water Supply Inventory, did not have any
preconceived ideas concerning extent or severity of
contamination. The first priority areas were designated as first
because EPA intended to sample all the wells (100 percent) in
these areas. In the second priority areas, EPA planned to sample
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about one-fourth of the wells. The criteria used to
differentiate first and second priority areas included proximity
to known mining areas, geographic location within the site, and
expected density of potable use shallow wells. The first
priority areas were within known mining areas, but were also
areas where EPA felt confident it could sample all the wells
without expending an inordinate amount of effort. The two areas
designated as second priority areas were expected to have
relatively large numbers of private shallow wells, so EPA planned
to sample only about 25 percent of the wells and not commit to
sampling all the wells unless results of the 25 percent sampling
indicated further sampling was warranted. One of the second
priority areas was immediately adjacent to, and potentially
downgradient of, the Galena subsite where ground water
contamination had already been documented, so EPA was concerned
about this area. The other second priority area was Lowell, the
only other area within the site where there was heavy use of the
shallow ground water resource.
The EPA did not necessarily expect to see a higher incidence
of contamination in the first priority areas. The degree of
contamination in the second priority areas, as compared to the
first priority areas, indicates that factors other than just
proximity to known mining areas play a role in the degree of
contamination in the waters of shallow wells. One of these
factors could be natural mineralization, but several factors in
addition to natural mineral occurrence must be considered, such
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as local geology, local fracture patterns, possible presence of
solution channels, pumping frequency and duration and others.
13. Comment; The conunenters stated that the wells
corresponding to J39B9065 and J39B9066 are outside the site
boundary and should not be included in the tabulation of
exceedances, and wells corresponding to J39B9062 and J39B9040
should not be included because they are not used as potable water
supplies.
Response; Wells J39B9065 and J39B9066 were located outside
the site boundary because they were intended to represent
background water quality. Neither of these wells exhibited
exceedances of MCLs or MCLGs and neither were counted as wells in
the second priority areas. The Sitewide Water Supply Technical
Memorandum (on page 12) states that 51 wells were inventoried in
the second priority areas, but only 49 were actually sampled. As
shown in Table 5 of the Technical Memorandum, the two wells
inventoried but not sampled were in the West Galena area.
One well in the Baxter Springs area (J39B9062) and one well
in Lowell (J39B9040) were not used as a potable water source
during the sitewide inventory. The well in Lowell was considered
representative of the area ground water and was used in the
assessment of exceedances. The shallow well in Baxter Springs
did not exceed primary MCLs or MCLGs, although is a valid well to
use to evaluate the ground water quality.
14. Comment: The commenters stated that only 4 of 49 wells
sampled within the Lowell and West Galena Survey Areas exceeded
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primary MCLs, and all exceedances were relatively minor and of no
likely health significance.
Response; The commenters correctly state that 4 of 49 wells
in the second priority areas were identified as having exceeded
the primary MCLs. The commenters1 contention that the four
exceedances are "minor" is open to interpretation and their
conclusion regarding health implications is without scientific
justification. The primary MCLs were promulgated under the
authority in the Safe Drinking Water Act of 1972 and were based
on evidence of known health effects.
The commenters contend that the selenium exceedance for the
well corresponding to sample J39B9022 (Well 23N) should be
excluded from the list of exceedances because it had only a minor
exceedance and because a subsequent sample indicated a selenium
concentration below the MCL. The issue of what should constitute
a "real exceedance" of drinking water standards has been raised
several times in the commenters1 letter. In performing the
remedial investigation of the ground water at the Galena subsite,
the EPA's position has been as follows:
a. Any sample taken as a part of the RI and passing quality
control tests is representative of the ground water
quality at the well at the time that the sample was
taken.
b. It is assumed that ground water quality is subject to
temporal variability, sampling variability and
analytical variability. The latter two are controlled
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by the QA/QC program.
c. Any well with at least one sample having an exceedance
of at least one drinking water standard is considered to
be a well that potentially exceeds the standards during
other times of the year.
15. Comment: The commenters believe that few, if any, of.
the shallow wells being used for domestic supplies have
exceedances of any standards. The commenters contend that only 9
percent of the wells have real documented exceedances.
Response; As previously discussed, all of the exceedances
reported are real exceedances and need to be treated as such.
16. Comment; The commenters believe that neither the
Sitewide Water Supply Technical Memorandum nor the AWS OUFS
provides adequate consideration of the hydraulic position of the
shallow wells sampled with respect to known mining disturbance.
Response; Definition of the hydraulic relationship between
an individual contaminated well and the "known mining" or "flint
area" involves a dynamic ground water system that makes it very
difficult to impossible. First, mining areas are not all
contiguous nor are they all in the "flint area." The water table
is relatively level, virtually much less than 100 feet across the
entire site. The ground water flows through fracture and joints,
resulting in a very wide range in transmissivity from well to
well. The private wells are completed in the same depth interval
as the mining areas. Essentially, any individual well can be
"downgradient" of a particular mining area if it pumps for a
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sufficiently long time. The individual wells are commonly
clustered in neighborhoods, which increases the potential
hydraulic connection and certainly the downgradient character of
each individual well. The hydraulic connection between specific
wells and mined areas could be verified, but at considerable
expense and at a considerable expenditure of time, and this would
still not contribute to or alter the remedial actions needed to
protect human health and the environment.
17. Comment; The commenters contend that the sampling
design was biased and, therefore, average concentrations of
metallic ions are not a valid measure of potential contamination.
Response; Ground water sampling was not biased towards
sampling the expected worst wells, or toward any other routine
that would invalidate the use of average concentrations. Some
areas were sampled to obtain data from about 25 percent of the
shallow wells, selecting wells that were distributed fairly
uniformly across the entire sampling area. Other areas were
sampled so that all wells were sampled. Neither of these
approaches would inherently bias an average concentration
calculated from the ground water data.
Some wells that exceeded MCLs were selected by EPA for
repeated analyses. In these cases, the average metals
concentrations for each of these wells were first calculated, and
then these averages were used to represent each well's water
quality when the overall average (for wells sampled only once and
for wells sampled several times) was calculated. This precluded
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the potential for the wells that: were sampled repeatedly to bias
the average when combined with wells that were sampled only once.
18. Comment; The average metals concentrations for the AWS
OUFS were computed using detection limit values for samples where
concentrations were less than detection limits. The commenters
believe this practice significantly distorted the calculated
averages.
Response; The commenters referenced the average values
calculated for selenium to show that the method for calculating
average metals concentrations was inappropriate. Selenium was an
exception to the rule, and the method for calculating average
metals concentrations in the AWS OUFS did, as the commenters
state, significantly distort the average calculated for selenium.
The primary problem was that the routine detection limit for
selenium at the EPA Region VII laboratory was 50 ug/1, five times
the MCL for selenium was not true for the other metals of
concern, so the method used to calculate average concentrations
in the AWS OUFS did not significantly distort the results for the
other metals. Furthermore, EPA has not regarded selenium as a
contaminant directly related to past mining activities in the
site.
The EPA's consultant determined that the average
concentration for selenium reported in the AWS OUFS (Table 3-1)
was invalid shortly after the OUFS was submitted to EPA and
advised EPA of this prior to signature of the AWS ROD. The
average metals concentrations in the revised Table 3-1 are very
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similar to average values calculated by the PRPs and submitted as
Table 1 in their comments on the Site-wide Water Supply Technical
Memorandum dated February 1, 1988. A copy of the revised Table
3-1 is shown below:
Table 3-1
CONCENTRATIONS OF TOTAL METALS
OBSERVED IN PRIVATE WELLS
Metals
Arsenic
Barium
Beryllium
Cadmium
Chromium (total)
Copper
Cyanide
Iron
Lead
Manganese
-Mercury
Nickel
Selenium
Silver
Zinc
Average Observed
Value (ug/l)a
28.9
83.5
1.8
5.6
6.8
14.5
10
1,115
25.5
92
0.138
23
3.8
6.9
841
Maximum Observed
Value (ug/l)a
31b
390,_
4b
180
120
140
- 10 '
26,000
230
3,400
0.44
270
24
11
15,000
*ug/l = micrograms per liter.
bln these instances there were values greater than those
listed; however, they were the results of higher detection
limits and were listed as less than the detection limit.
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19. Comment; The commenter inventoried the volume of mine wastd
rock material and the volume of available disposal areas. He
found in the Galena are there is enough space in open pits and.
mine shafts to dispose of all the mine waste rock.
Response; The EPA had not made such an elaborate
investigation of the volume of disposal space, but had also
reached the same conclusions.
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