.r"'--
Un~ed States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPAlRODJROS-931239
September 1993
PB94-964103
.
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&EPA
Superfund
Record of Decision:
,
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Himco Dump, IN
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u . S. Environmental Protection Agency
Region 11/ Hazardous Waste
T9chnical Information Center
84 1 Chestnut Street I 9th Floor
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-"HozadOOS W~C6ltectiori-1 >
Information Resource Center
US EPA Region 3
Philadelphia, PA 19107
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50272-101
REPORT DOCUMENTATION 11. REPORT NO. 2. 3. Recipient's Aeew~ No.
PAGE EPA/ROD/R05-93/239
4. "'18 and SubtiU8 5. Report D8ta
SUPERFUND RECORD OF DECISION 09/30/93
Himco Dump, IN 6.
First Remedial Action - Final
7. Whorts) 8. Performing Organization R8pt. No.
8. Performing Organization NaIl'l8 and Address 10 ProJect TuklWork Unit No.
11. Contract(C) or Gran(G) No.
(C)
~
12. ~ng Organization Name and Address 13. Type of Report & Period CoV8I8CI
U.S. Environmental Protection Agency
401 M Street, s.w. 800/800
Washington, D.C. 20460 14.
15. Suppl8m8nlary Not.
PB94-964103
16. Ab8trac:t (Umlt: 2IDO~)
The 100-acre Himco Dump site is an active municipal landfill in Elkhart, Elkhart
County, Indiana. Land use in the area is predominantly agricultural, residential, and
light industrial, with a wetland area located west of the site. The site is bounded by
woodlands and the northernmost extent of a. gravel pit pond to the north; by County Road
lQ and private residences ta the south; by the Nappanee Street Extension to the e~st;
and a section of land west of two ponds to comprise the west. From 1960 to 1976, the
Himco site operated as a solid waste landfill. Refuse was placed directly onto the
ground surface or disposed of in unlined trenches. In 1971, the State identified the
Himco site as an open dump. In 1974, residents near the site complained about color,
taste, and odor problems with the ground water from their shallow wells, and samples
from these wells were found to be highly contaminated with manganese. By 1990, the
wells showed high concentrations of sodium, which posed a chronic health threat to the
residents. Residents with wells that were affected by site contamination were connected
to the municipal water supply. In 1976, the landfill was closed and covered with
approximately one foot of' sand overlying a calcium sulfate layer. In 1984, EPA
inspections identified that ground water downgradient of' the site was contaminated by
(See Attached Page)
17. Document Analysis L Descriptors
Record of Decision - Himco Dump, IN
First Remedial Action - Final
Contaminated Media: soil, debris
Key Contaminants: VOCs (PCE, TCE, toluene, xylenes), other organics (PAHs, phenols),
metals (arsenic, lead), inorganics (cyanide)
b. IdentI~T.rms
c. COSA11 FlaldIGroup
18. Availability Stat.meN 18. Security CIasa (This Report) 21. No. of Pagn
None 84
20. Security Class (Thi. ~ga) 22. Price
None
(Sea ANSI-Z38.18)
SMIMtnlctioM on ~,,-
OPTIONAL FORM Z72 (4-77)
(~ NTIS-35)
Department of Comrn8rc8
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EPA/ROD/R05-931239
Himco Dump, IN
First Remedial Action - Final
Abstract (Continued)
VOCs, SVOCs, and metals. Leachate seeps also were observed. During the RI, a "hot spot"
was identified at the southwest border of the landfill, which showed high levels of VOC
contamination. In 1992, as part of an emergency removal action, EPA located, removed and
disposed of seventy-one 55-gallon drums containing PRPs off site. Although other hot spots
have not been identified to date, it is not certain whether additional drum pockets exist
onsite. This ROD addresses the contaminated surface and subsurface soil in the southern
portion of the landfill. The primary contaminants of concern affecting the soil and
debris are VOCs, including PCE, TCE, toluene, and xylenes; other organics, including PAHs
and phenols; metals, including arsenic and lead; and other inorganics, including cyanide.
The selected remedial action for this site includes installing a composite barrier cap
with a vegetative layer over 58 acres of the site, with an active vapor phase carbon
system to treat off-gases from the landfill; providing for a contingent remedy to install.
a ground flare system, if landfill gas characterization studies indicate VOC emissions
exceed ARARs; mitigating any affected wetlands; monitoring ground water; and implementing
institutional controls, including deed, ground water, and land use restrictions, and site
access restrictions such as fencing. The estimated present worth cost for this remedial
action is $11,821,000, which includes an estimated annual O&M cost of $210,000 for 30
years.
PERFORMANCE STANDARDS OR GOALS:
Not provided.
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J'
NOTICE
THIS DOCUMENT HAS BEEN REPRODUCED
FROM THE BEST COpy FURNISHED NTIS BY
THE SPONSORING AGENCY. ALTHOUGH IT'S
RECOGNIZED THAT CERTAIN PORTIONS ARE
IllEGIBLE, IT IS BEING RELEASED IN THE
INTEREST OF MAKING AVAILABLE AS MUCH
INFORMATION AS POSSIBLE.
n
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RECORD OF DECISION
Himco Dump
Elkhart, Indiana
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DECLARATION
SELECTED REMEDIAL ALTERNATIVE
FOR THE
HIMCO DUMP SITE
ELKHART, INDIANA
statement of Basis and PurDose
This decision document presents the selected remedial action for
the Himco Dump Site, Elkhart, Indiana, which was chosen in
accordance with the Comprehensive Environmental Response,
compensation, and Liability Act (CERCLA) of 1980, as amended by the
Superfund Amendments and Reauthorization Act (SARA) of 1986, 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.
Assessment of the Site
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action in this
Record of Decision (ROD), may present an imminent and substantial
endangerment to public health, welfare, or the environment.
DescriDtion of the Selecte~ Remedy
The purpose of this remedy is to eliminate or reduce migration of
contaminants to the groundwater and to reduce the risks associated
with exposure to the contaminated materials.
The major components of the selected remedy include:
Construction of a composite barrier, solid waste
landfill cover (cap);
Use of institutional controls on landfill property to
limit land and groundwater use;
- (J
Installation of an active landfill gas collection
system including a vapor phase carbon system to treat
the off-gas from the landfill;
An enclosed ground flare system will be implemented if
landfill gas characterization studies indicate VOC
emissions exceed ARARs (Indiana Administrative Code 326
IAC); and
Monitoring of groundwater to ensure effectiveness of
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the remedial action and to evaluate the need for future
groundwater treatment.
Statutory Determinations
The selected remedy is protective of human health and the
environment, complies with Federal and state requirements that are.
legally applicable or relevant and appropriate to the remedial
action, and is cost effective. This remedy utilizes permanent
solutions and alternative treatment or resource recovery
technologies to the maximum extent practicable. However, because
treatment of the principal threats of the site was not found to be
practicable, this remedy does not satisfy the statutory preference
for remedies that reduce the toxicity, mobility, or volume as a
principal element. A removal action conducted at the site in 1992
removed drums and waste material from the only hot spot identified
in the landfill during the Remedial Investigation. Beyond that,
the size of the landf ill precludes a final remedy in which
contaminants could be excavated and treated effectively.
r:;
Because this remedy will result in hazardous substances remaining
on site above health-based levels, a review will be conducted
within five years after commencement of the remedial action to
ensure that the remedy continues to provide adequate protection of
human health and the environment.
state Concurrence
The state of Indiana concurs with the selected remedy.
of Concurrence is attached to this ROD.
The Letter
j;//p; I
4ft: ~ /9f3.
Date
Valdas V. Ada
Regional AdDii
': i
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TABLE OF CONTENTS
A.
Site Location and Description. . . . . . . . .
B.
site History and Enforcement Activities
. . . .
. . 1
. . 2
C.
Highlights of community Participation.
. . . . .
........
. . 3
D.
Scope of the selected.Remedy. . . . .
. . . . . .
E.
Summary of Current Site Conditions.
. . . .
F .0
Summary of site Risks. . . .
. . . .
G.
Rational for Further Action.
. . . .
.......
H.
Description of Alternatives
. . . . .
. . . . .
1.
Summary of Comparative Analysis of Alternatives.
J.
The Selected Remedy. . .
. . . . . .
. . . . . .
K.
statutory Determinations. . . .
. . . .
. . . .
Responsiveness Summary
. . . . . 4
. . 4
. . 8
. . . . 12
. . . 13
. .16
. .19
. . . .
. .20
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FIGURES AND TABLES
Fiaures
1 - Location Map
2 - Site Map
3 - Approximate Landfill Boundary
4 - Trench Locations
5 - Semi-Volatile Compounds Detected
in Subsurface Soils
Tables
1 - Summary of Inorganic Analytes Detected
in Surface Soil
2 - Summary of Volatile organic
Compounds Detected in Surface Soils
3 - Summary of Semi-Volatile Compounds Detected
in Surface Soils
4 - Chemicals of Potential Concern
5 - Summary of Estimated Carcinogenic
Risk-Current Populations .
6 - summary of Estimated Carcinogenic Risk -
Hypothetical Future Residential Populations
7 - Summary of Noncarcinogenic
Risk-CUrrent populations
8 - Summary of Noncarcinogenic Risk -
Hypothetical Future Residential popuulations
9 - Exposure Scenarios for Ecological Populations
10 - Cost Summary
11 - Estimated Cost for the Selected Remedy
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Follows Paae
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1
6
7
8
8
8
8
9
11
11
11
11
12
19
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SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
Himco Dump
A.
SITE LOCATION AND DESCRIPTION
The Himco Dump site is a closed landfill located at County
Road 10 and the Nappanee Street Extension in Cleveland Township,
adjacent to the city of Elkhart, Elkhart County, Indiana. The
site is located approximately two miles north of the st. Joseph
River which runs east-west through the City of Elkhart. See
Figure 1. The site covers approximately 100 acres and is bounded
on the north by a tree line and the northernmost extent of a
gravel pit pond; on the south by County Road 10 and private
residences; on the east by the Nappanee Street Extension; and a
section of land west of two ponds (an L shaped pond called the
"L" pond, and the small pond) comprise the western boundary.
The landfill area is covered with a layer of sand, under which is
a layer of white, powdery, calcium sulfate. The western half of
the landfill cover is vegetated with grasses; the eastern half
with grasses, bushes, and young trees. An area south of the
landfill and north of County Road 10, the construction debris
area, contains many small piles of rubble, concrete, asphalt, and
metal debris. The construction debris area extends across the
landfill boundary and onto property owned by adjacent landowners.
There was an abandoned gravel pit operation in the northeast
corner of the site. An old truck scale and other concrete
structures were also present in this area. During an inspection
in December, 1992 by the Indiana Department of Environmental
Management [IDEM], it was observed that these structures had
recently been tampered with and removed. The gravel pit is
filled with water which is approximately 30 feet deep. Two
smaller and shallower ponds, the L pond and the small pond, are
on the west side of the site. See Figure 2.
The site is not fenced. In the vicinity of the site are agricul-
tural, residential, and light industrial land uses. There is an
access road which leads from the southeast corner of the site
near the intersection of County Road 10 and Nappanee Street.
Extension. A locked gate is present across this road; however,
vehicles can easily drive around the gate and enter the site.
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FIGURE 1
~ ELKHART MUNICIPAL
I AIRPORT
Bristol Street
Elkhart
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FIGURE 2
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B.
SITE HISTORY AND ENFORCEMENT ACTIVITIES
The Himco site was privately operated by Himco Waste Away Ser-
vice, Inc., and was in operation between 1960 and september 1976.
As of January 1990, the parcels of land which comprise the
landfill were owned by the following individuals or corporations:
Miles Inc.; CLD corporation; Alonzo Craft, Jr.; and Indiana and
Michigan Electric Company.
The area was initially a marsh and grassland. There was no
liner, no leachate collection, nor gas recovery system
constructed as part of the landfill. Refuse was placed at ground
surface across the site and in trenches excavated to
approximately 10 to 15 feet deep, the width of a truck and 30
feet long, in the eastern area of the site. Solid waste refuse
was reportedly dumped in the trenches and burned.
In 1971, the Indiana State Board of Health (ISBH) first identi-
fied the Himco site as an open dump. In early 1974, residents
along County Road 10 south of the Himco site complained to ISBH
about color, taste, and odor problems with their shallow wells.
Analyses were conducted from samples of six shallow wells along
County Road 10, ranging in depth from 20 to 30 feet. These
samples showed the wells were highly contaminated with manganese.
Mr. Chuck Himes, the principal landfill operator, replaced these
wells with deeper wells ranging in depth from 152 to 172 feet
below ground surface. By mid 1990, the wells showed high concen-
trations of sodium which posed a chronic health threat to the
residents. By November 1990, municipal water service was
provided to those residents whose wells were affected. The cost
of this action was financed by Miles Inc. and Himco Waste-Away
Service, Inc.
In 1976, the landfill was closed. and covered with approximately
one foot of sand overlying a calcium sulfate layer.
In 1984, a U.S. EPA field investigation team conducted a site
inspection. Analyses from monitoring wells showed that the
groundwater downgradient of the site was contaminated by volatile
organic compounds (VOC~), semivolatile organic compounds (SVOCs),
and metals. During the site inspection, leachate seeps were
observed.
In June 1988, the Himco site was proposed for the National
Priorities List (NPL) and in February 1990, was officially placed
on the NPL and designated a Superfund site. The site Remedial
InvestigationfFea.sibility Study (RIfFS) was begun in 1989 and
completed in 1992.
.During the Remedial I~vestigation (RI), a. "hot spot" (an isolated
area of highly concentrated. contaminants) was identified at the
southwest border of the landfill. See Figure 2. This area
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showed high levels of VOCs contamination. On May 22, 1992, U.S.
EPA initiated an emergency removal action, which located and
removed 71 55-gallon drums containing VOCs such as toluene and
ethylbenzene. Although other hot spots have not been identified,
it is not certain whether additional pockets of drums exist.
C.
HIGHLIGHTS OF COMMUNITY PARTICIPATION
U.S. EPA issued a fact sheet to the public in July 1990, at the
beginning of the RI. The Agency also hosted a public meeting on
July 12, 1990, to provide background on the Himco Dump site,
explain the Superfund process, and provide details of the
upcoming investigation. U.S. EPA issued a second fact sheet in
May 1992, to notify residents in the vicinity of the site of the
"hot spot" assessment and possible emergency removal action (this
action was conducted, as stated above). .
The RIfFS reports and the Proposed Plan for the Himco Dump site
were released to the public for review in September, 1992.
Information repositories have been established at the two
following locations: the Elkhart Public Library Reference
Department, 300 South Second Street, Elkhart, In 46516; and the
pierre Moran Branch Library, 2400 Benham Avenue, Elkhart, IN
46517. The Administrative Record has been made available to the
public at the U.S. EPA Docket Room in Region V and at the two
libraries.
A public meeting was held on october 6, 1992 to discuss the FS
and the proposed Plan. At this meeting, representatives from the
U.S. EPA and IDEM answered questions about the site and the
remedial alternatives under consideration. Formal oral comments
on the Proposed Plan were documented by a court reporter. A
verbatim transcript of this public meeting has been placed in the
information repositories and administrative record. Written
comments were also accepted at this meeting. The meeting was
attended by approximately 70 persons, including local residents
and PRPs.
The FS and proposed Plan were available for public comment from
September 30, 1992 through November 30, 1992. Comments received
during the public comment period and the U.S. EPA's responses to
those comments are included in the attached Responsiveness
summary, which is a part of this ROD. Advertisements announcing
the availability of the Proposed Plan, start of the comment
period and extension of the comment period were published in the
Elkhart Truth.
The public participation requirements of CERCLA sections 113 (k)
(2) (i-v) and 117 of CERCLA have been met in the remedy selection
process. This decision document presents the selected remedial
action for the Himco Dump site chosen in accordance with CERCLA,
as amended by SARA and, to the extent practicable, the National
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Contingency Plan (NCP). The decision for this Site is based on
the administrative record.
D.
SCOPE OF THE SELECTED REMEDY
~
This ROD addresses the final remedy for the Site. The threats
posed by this Site to human health and the environment result
from source material in the landfill and from surface and
subsurface soil in the southern portion of the landfill (referred
to as the construction debris area) and in an area immediately
south of the landfill. This response action will contain the
source material and will be conducted in accordance with
applicable or relevant and appropriate requirements of Federal
and State law. u.S. EPA considers containment of the landfill
material, which is a potential source of groundwater
contamination, to be the most practicable remedy.
This remedy utilizes permanent solutions and alternative
treatment technologies to the maximum extent practicable for the
site. However, because treatment of the principal threats of the
site was not found to be practicable, this remedy does not
satisfy the statutory preference for treatment as a principal
element of the remedy. The size of the landfill and the fact
that it is not known where or if any remaining on-site hot spots
exist that represent the major sources of contamination, preclude
a remedy in which contaminants could be excavated and treated
effectively.
Because this remedy will result in hazardous substances remaining
on-site above health-based levels, a five year review will be
conducted to ensure that the remedy continues to provide adequate
protection of human health and the environment.
E.
SUMMARY OF CURRENT SITE CONDITIONS
The RI performed at the Himco Dump Site was designed to
characterize the nature and extent of contamination posed by
hazardous materials at the site and to conduct a human health
risk and ecological assessment. The RI included sampling and
analysis of groundwater, surface and subsurface soils, waste mass
gas under the landfill cover, leachate collected from within the
landfill, and surface water and sediments from the three ponds on
the site (quarry pond, L-pond and small pond).
Based on the results of the RI, u.S. EPA has determined that the
threats to human health and the environment are through future
exposure by ingestion, inhalation or direct contact to VOCs,
SVOCs and inorganic compounds through soil and groundwater
pathways at the site. u.S. EPA has also determined that there is
a significant potential for contamination of the aquifer because
of the lack of any adequate natural or man-made barrier to impede
leachate flow into the' aquifer.
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The following conditions were observed at the site:
1.
Topography
The Himco Site is located in Elkhart County, Indiana.
Elkhart County lies in the Great Lakes section of the
Central Lowlands Physiographic Province. The present
topography is a result of continental glaciation. The land
surface consists of nearly level and gently sloping eolian
and outwash sands in the northern part of the county; level
to moderately sloping outwash terraces and plains in the
northern and central portions of the county; and nearly
level to strongly sloping glacial till plains in the eastern
and western portions.
The land surface elevation in Elkhart County ranges from 950
feet in the southeast to 740 feet Mean Sea Level (MSL) in
the west at the St. Joseph River (USGS, 1981).
2.
Geology
The general site area is characterized as sand and gravel
outwash deposits, comprised of alternating beds, varying in
thickness, of poorly- to well-graded sands and gravels, and
gravel-sand-silt mixtures ranging in thickness from
approximately 200 to 500 feet below ground surface with an
average thickness of 175 feet. These outwash deposits
constitute the primary groundwater aquifer at the site.
Minor seams of silt and clay were also encountered, but
there was no indication of a consistent confining layer
beneath the site.
3.
Hydrology
Groundwater occurs in the study area at depths ranging from
5.to 20 feet below ground surface ranging from 752 to 756
feet (MSL). The elevation of the bottom of the waste mass
is estimated to range from 755 to 760 feet (MSL) The
outwash aquifer is unconfined below the Himco site, and the
silt and clay confining layer is absent. Groundwater flow
is generally to the south, southeast, toward the st. Joseph
River, a groundwater discharge area. Local groundwater flow
appears to be consistent with regional conditions. The
average groundwater flow velocity is estimated to be 121
feet/year. Three specific groundwater characteristics which
may be important factors in contaminant migration include
low horizontal gradient, low upward vertical gradients, and
fluctuations in water table levels. Groundwater
fluctuations at the Himco Site may be important because
water table elevations are relatively near the landfill
waste. Upward fluctuations may result in a more direct
5
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contact between groundwater and the waste mass thereby
providing a more rapid mechanism by which contaminants from
the landfill enter the groundwater system.
4.
contamination
a.
Source
The source of contamination from the Himco Site is the
landfilled waste. A proper cap was never installed, thereby
allowing precipitation to infiltrate through hazardous
constituents in the landfill and leak into the groundwater.
In addition, there is a possibility of air emissions of VOCs
and SVOCs through the existing cover. Test pit excavations
in the landfill revealed the presence of a non-homogenous
waste matrix. In addition, leachate was observed in the
majority of trenches excavated at elevations above the water
table. Leachate collected at the southwest corner of the
landfill was red and brown and separated into two phases.
The floating phase of the leachate contained approximately
48 percent toluene by weight. This location has been
referred to as the "hot spot" in the landfill. An emergency
removal was conducted in May 1992 to remove this hot spot.
Figure 2 shows the location of the hot spot.
Generally, three fill layers were observed consistently in
the landfill. The top layer can be characterized as a
silty, sand cover, soil fill which ranged in thickness from
a thin veneer to several feet. Underlying the sand cover,
and in some cases at ground surface, calcium sulfate was
found. It varied in thickness from a few inches to as much
as nine feet at the southeastern, central, and southern
areas of the landfill. Overall, the thickness was found to
be less than 2 feet in 62.5 percent of test pit excavations.
The .areal extent of the calcium layer is shown in Figure 3.
Beneath the calcium sulfate layer, an estimated 15- to 20-
foot thick waste layer was found. This waste layer was
found to include paper, plastic rubber, wood, glass, metal
(including drums), as well as small amounts of hospital
wastes.
Non-native soil mixed with construction debris was observed
in test pits outside the landfill area along the south
central and southwest edge of the landfill. This section is
referred to as the construction debris area and ,is
identified in Figure 3. No calcium sulfate was found in
this area. SVOC contamination was found to be most
prominent in surface soil samples collected here.
b.
Groundwater
Two rounds of groundwater sampling during the RI revealed
6
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I.
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lell
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.liaited vroundvater eontaainaUon out. ide the boundarie. or
the va.te. In 9eneral, trace uounu of VOC8 and &VOC.. vere
deucted in vroundvater .upl... DuriftCJ RI Pba.e I
.88pU,., tricbloroethene va. detected above 1ICL8 in two
_l~., 071 and 072, vbich are located approxi..tely 2,000 feet
off-.ite and .ide vradient to the 81800 .ite.
In the -11. .outh of the landfill, 1ICI.8 for nine chaical.
V8Z'8 exceeded at lea.t once I bowever, it baa not yet Men
..tabU8bed that the cont..ination re.ulu froa the .ite.
IIo8t vere inorvanice (antiaony, ar.enie, berylliua,
cbraaiua, lead, nickel and nlfate), althou9b low level. of
VOC8 _re al.o d.tected. 88rylliua eontaainaUon va. found
at .iailar detection leve18 in backvround -11.. Ar.enie
and antiaony vere detected at .ivnificantly bi9ber .
concentratioM than in backvround _11.. Except tor
berylliua, nickel and nlfate, all the chaical. _ich
exceeded .1ICL8 .outh. of the landfill al.o exceeded 1ICL8 in
the trench l..cbate 88Jlpl... .
c.
Leachate
Leachate va. .aapled frOll four te.t piu and analyaad for
VOC8, 8VOC8, pe.tieid../PC88, Mtal./cyanide, and vater
quaUtr. Pivure 4 8b0V8 trench locatioM. Leachate froa
tat p t TL5 .eparatad into two pba... of alao.t pur.
product and leachate. Analy.i8 of the pure product pha..
8b0W8d approxiMtely 50' toluene.
COftC8ntratioM of 'VOC and inorvanie contaainant. detected in
leachate vere tYPicallr order. of -vnitwte bi9ber than
fJI"OUftCIvater concentrat OM. 'l'be bip..t concentration. of
VOC8 and 8VOC8 vere det~ed 1n l..chate froa TL5. Trace.
of pe8tieide. vere detected in leachate TLl and TL2.
'1'ber8 are no adequate natural.' or 88ft-_de barrier. to
i.olate leachate .fraa fJI"OUftdvater at thi8 .ite. Laachate
-y ~tially enter the vroundvater due to the vravitr
flow. 'COntaainanu enterinv the vroundvater ..y potent ally
up'ate off-.ite throup the local and revional vroundvater
flow. .
d.
8011
contu1nanta ware detected priJlar11y in eurface 80118.
Areenie and berylliua vere detected in nrface .oil eaaple.
located acroe. the -.tern balf of the .ite, around t;be
. quarry pond, and in the 8outh-central area, vbich 18
cbaracterbe4 by non-native .011 and coMtruction dari8.
ft8 bi_..t concentratioM of ar.enie vere detected in .oil
88Jlple. frOll the .outh central area. 88rylliua V88 detected
at MVeral locationa at relatively conai8tent
7
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concenuationa.
voc. vere detected in ..ny place. acro.. the .ite at low
concanuationa. SVOC .011 contuination va. found to be
ao.t proainent in .uple. collected in the .outh-cenual
area vbieb 18 cbaracter1aed by non-native .011 and .
conatruction dur18. Pe.ticid.. vere d.tected in two .011
.uple. collected froa thi. area. A .u.aary of inorganic,
VOC, and SVOC concenuation ral\9" ..y be found in tabl.. 1,
2, and 3 r..pectively. Fivure 5 pr...nt. th. location.
where IVOC. vere det.cted.
F.
StDIIIAItY 01" sron: RYRS
The analytical data collected duriftCJ the AI and the ba.eUne r18k
a..e...ant indicated the pre.ence of contuinant. in variou
.edia at level. that ..y pre.ant a ri.k to huaan h.alth. .
Pur.uant to th. IfCP, a ba.eline ri8k a..e...ent va. perfOrJIed .
ba.ed on data froa the AI. The ba.eline ri.k a......ent a..WI..
no corrective action v111 take place and that no .ite-u.
re.uictiona or inatitutional conuol. .ueb a. fanciftCJ,
groundvater u.. r..uictiona or conatruction re.Uiction. vill be
iape.ed. The ri8k a.......nt then det8rJlin.. actual or potential
carcinOCJanic ri8k8 or toxic .ffecta th. eb..ical contuinant. at
the .ite po.e under either currant or future land ue
a..uaption..
1.
Contuinant Identification
ft. 88d1a of conc.rn for huaan expo.ur.. for curr.nt and
future .canario. vera identified priaarily a. qroundw~ter
and 8011. vhich have bean contuinated froa the landfilled
va.t88. DuriftIiJ the AI .everal chaica18 in differ.nt. .edia
vere detected and a l18t of wch..ieal. of potential concern-
va. dev.loped uinCJ the follovinv criteria:
Any ch..ical detected at lea.t once in any on-.ite
8Oil, vroundvatar, leachate, .urface vater or
.edillent .uple va. conaidered to be a po..ible
eb..ical of concern. .
-
leveral cb..ical. known to be ...ential for huaan
nuuition vere .1illinated. fte.e ch..icala v.re
pr...nt at leval. that are con.idered non-toxic.
~1e. conaidered to be backqround vere not uad
in tbe ..laction proce8., nor vere the data froa .
r..idantia1 ve11.. jut 80uth of the landfill due
to the uncertainty r8CJardiftCJ the intaqri-ty of
tho.. r..idantial vell..
-
.
~
-------
TABLE 1
SUMMARY OF INORGANIC ANALYTES DETECTED IN SURFACE SOIL
HIMCO DUMP SUPERFUND SITE
.ELKHART,INDIANA
1992
Range of
9Sf7c . Concentrations
Background (mg/kg) Lower/Upper Levels Detected
Analyte B-02 B-04 B-06 (Background) (mg/kg)
Aluminum 5,lOO(J) 5,720 3,920(J) 3,655/6.172 9.7(B)-6,730(J)
Antimony ND ND ND 4.3/4.3 3.l(BJ)-46.8
Arsenic 1.5(B) 2.0(B) 1.1(BJ) 0.91/2.2 0.47(B)-5.8
Barium 62 61.1 35.5(BJ) 32.2/73.6 1.3(BJ)-101
Beryllium .69(BJ) .27(BJ) ND ND/O.77 0.20(BJ)-0.9l(~J)
Cadmium ND ND ND .06/.06 1.1(B)
Calcium 386(B) 498(B) 736( B) 294/7&6 360(B)-321,OOO(J)
Chromium 6.5(J) 7.1 4.5 4.2/7.9 1.1(B)-13.2
Cobalt 3.7(B) '3.3(B) ND 0.49/4.7 1.5(B)-5.3(B)
Copper 4.7(B) 4.3(BJ) 3.8(BJ) 3.7/4.9 1.3(B)-216
Iron 6.370 6,740 4,690(1) 4,429/7,437 9.8(BJ)-10.100
Lead 7.8 7.0 8l(J) ND /90 0.5(BJ)-245(J)
Magnesium 762(B) 976(B) 44O(BJ) 355/1,097 14.6(BJ)-14.000
Manganese 402 421 70(J) 2,519/569 1.3(BJ)-561(J)
Mercury ND ND ND .06/.06 0.13(J)-0.54(J)
Nickel 6.5(B) 7.5(B) ND 29/9.8 2.4(B)-12.0
Potassium 252(B) 213(B) 115(B) 96.2/291 86.6(B)-678(B)
Selenium O.25(BJ) ND ND 0.23/0.44 0.27(BJ)-1.4(J)
Silver ND ND ND 0.50/0.50 0.49(B)-2.8(BJ)
Sodium ND ND ND 5.0/5;0 20.8(B)-9O.6(B)
Thalli~ ND ND ND 0.24/0.24 ND
Vanadium 11.8 11:6 10.4(BJ) 10.2/12.3 1.6(BJ)-19.1
Zinc 20.5 22.4 8.4 6.7/27.6 1.7(B)-229
Cyanide ND ND ND 0.60 /0.60 1.3-24.3
Qualifiers
ND - Below detection limit
B - Analyte found in the associated blank as well as in the sample
J . Indicates an estimated value
Half of the detection limits were used for nOD-detects
A/R/HIMCO/AJ2
-------
TABLE 2
SUMMARY OF VOLATILE ORGANIC COMPOUNDS DETECTED IN SURFACE SOILS
HIMCO DUMP SUPERFUND SITE
ELKHART, INDIANA
1992
Compound
Background.
(ug/kg)
Range or
Concentrations
Detected
( ug/kg)
Mcthylcnc Chloridc
Acctonc
Carbon Disulfide
1,1- Dichloroethenc
2-Butanone
Tetrachloroetnene
Trichlorocthcne
Toluenc
Ethyl Benzene
St)Tene
Xylenes (total)
1,2-Dichloroethene (total)
1, 1, I-Trichloroethane
ND
ND
ND
ND
ND
ND
ND
8
ND
ND
ND
ND
ND
3(J)-16
8(BJ)-14O
0.8(J)
5(J)
2( J )-8
6(J)
0.9(J)-4(J)
2(J)-31
0.7(J)-2(J)
0.8(J)
0.7(J)-6
ND
ND
Qualifiers
ND - Bclow dctection limit
J - Indicates an estimatcd value
. - Samples from borings B-02, B-04, and B-06 (0' to 2' )
A/R/HIMCO/AJ2
-------
.. ____.e.__-o_- ---- ---. ..
TABLE 3
SUMMAR\' OF SEMI-VOUnLE COMPOUNDS DETEmD IN SURFACE SOILS
HIMCO DUMP SUPERFUND sm
~T,INDIANA
1992
.... 01
C....tndc8I
lI.dIpoud . ...... ANft.
Compoud (8l/1li) ~... (8I/IrI)
NapbtbaleDe NO 18(J)
2-Metbyb!apbtbaleDe NO 18(J)
Dimetbylpbtbalate NO .1(J)
1,4-DichlorobeDZeDe 80 12O(J)-210(J)
DietbylpbtbaJate 8O(J) NO
BeDZOic Acid NO 75(J)
AceaapbtbeDe NO 59{J)-310(J)
DibeDZOfuru NO 23(J)
AUOfeDe NO 43(J)-W(J)
PbeDaDWeDe NO 42(J)-1.5OO
ADtbraceDe ND 8Z(J)-Z4O{J)
Di-D-butylpbtbalate l00(J) 92(J~J)
Auoruwac NO 17(J)-2,800
PyreDe NO ~J)-2,OOO(J)
ButylbeDZylptbalate ND ]OO(J)
BeDZO( a)utbraceac NO - 2:S{J)-l,300
CJuyseae NO. 37(J)-1.6OO
bii(2-Ethylbcxyl)pbtbalate 93(J)-S7O(J) 18(J)- 7 .8OO(J)
Bcuo(b )Ouor8lltbeae NO 67(J)-3,D)
Bcuo(k)OuorutbeDe NO 82{J)-1, 100
Bcuo(a)pyrac NO 41O(J)-2,200
lDdcDo(1,1,3-cd)pyrae NO 2:1O{J)-3, 100
Dibeuo(aJa}alllllrlccDc NO M(J)-5SO(J)
BcDZD(J,h,i)payIeDc NO 15O{J)-3,!OO
CubuDIe NO 36(J)
Total CU~- PARI NO 138(J)-14,25O(J)
Total Nc8-carciDopDic PAIls NO 51(J)-8,34O(J)
()uaIifien
NO Below dctcc:lioD limit
J - lDdiQta u estimated value .
. - Samples from boriDp B.(J2, 8-04, aDd ~ (0' 10.2'.)
-------
. ,
.... ---....
--....,
'~"'r
~--'.J.
"/ \
-
....---........
.. L f). A
6-
t=
A-
F ..-
O~
(!-
(I-
.-
"'.. II
0-
(!-
1=
--
.
J
0Il1O- -
II J
.
e
o
!i&
'.iP.
:111
~il
;.
i
...
-------
Oft SgsttlllS. Me
TAILE
tRO~tCS :
Alua1a\18
ADcmoay
An8aie
iari\18
hryllluD
Cada1\18
Chrcai\18
Cobalc
troD
Lead
K8reury
Kicul
Silver
Tball1\18
Vuaadi\18
C)'u1d.
OaGAnCS:
wunLES
1.1-Dicbloroecbaa8
1.1-D1cblor08cb8a8
1.1.1-Tricbloroecbaa8
1.~-Dieblor08cb8a8
2-~UDoa8
2-Beuaoa8
4--cbyl-2-p8acuoa8
Ac8t=-
leU8a.
Ir08Odicblor088CbaD8
Carboa diau1fi48 .
. CIalorobeu8a8
Qalor08CbaD8
Qa1orofora
Itb,lbeu8u
118tb,l8D8 cblori48
Ityrn8
t8tracbloro8tblu
to1u8U
~1cb1oroetblD8
Ym,l cbloride .
1,1.8.
4
CB!HlCALS or n1IDtUL COIICDII - IDICO DCKr SIn
SanvoUTIUS
1.4-Dieblorob8aa8U
2.4-Dt88cb,lpbn01
2-M8cb)'luphtbal8a8
:""cb)'1phno1
4-M8u,lpbaaol
Ac8D8pbtbau
Aceupbc"'lau
ucbrac8D8
l8D8o(a)aDcbrac8D8 .
18aao(a)PJ!'8D8 .
l8D8o(b)fluoruthea8
18aao(k)fluoraatb8a8
leaao(l.b.i)p8ry18a8
18D801c Acid
18U11 aleohol
bi.(2-Etbylb8SJ1)
pbchalace .
lut,lb8aaylpbChalaC8
Cbry.8U
Carbaaole
Dib8Daofur8D
D1b8u(a.b)ucbrac8n8
Di.cbylpbthalaC8
Dt88c..,lpbcbalaC8
Di-a-bucylpbcbalat8
D1-e-octylphtbalac8
rluoraDcb8D8
nuor.8
lDdaao(1.2.3-c4)
. PJl'n8
lapbtha1au
fb8UDCb1'.8
fb8Dol
~au
nrrIcmIS/PCI'.
4.4'-1JD'r
4-4 ' -DIll
AUria
alpu-IBC
alpba-c:b1orc18D8
beca-18:
DieUdD
EDdon1faD 11
,---CblorGaD8
Bepcaeblor
'ol,cblor1DaCad
biphea,l -
Aroclor 1248
I8OI-CLP C1IDIlCAL5:
_naid8. 418.0198d
Chlorid8
lIitropa. _oa1a
Mitro,8a. aicrac. ,
aitriC8
lbo.pbon.
. Sulface
p
-------
..,~.~--- --'. .
. u_--.-- '-
. The cb_ical. of potential concern are li.t:ed in Table...
,
2.
Human Health Effect.
The health .effect. for the contaainant. of concem ..y be
found in Voluae 5 of the RI.
3.
Expo.ure Aa.e...ent
The ba.eline ri.k a..e...ent exaained potential pathway. of
concem to huaan health under both current ancS future lancS-
u.e .cenario. for the landfill property and .urroundin9
area.
The follovin9 pathway. were .elected for detailed evaluation
under current-u.e conditions: .
- Inhalation of airbome particulate. .or voc. relea.ed froa
the .ite (re.ident. northea.t of the .ite ancS dirt-bike
rider.on-.ite),
- Incidental iftge.tion of .urface .oil by uupa..er. while.
dirt-bike ridin9,
- Inge.tion of .urface water ancS .edi8ent while wadift9 or
fi8hift9,
- Deraal contact with .urface water while wadin9.
The follovift9 pathway. vere .elected for detailecS evaluation
under future-u.e conditions and include future ruidential,
co_ercial, a9ricultural, or recrutional .e.. Future re.identa
and worker. were evaluated both on the landfill area an4 .o\ith of
the landfill. ArJricultural worker. were evaluatecS on the
landfill area only. The pathway. are:
- Inhalation of airbome particulatu or VOC8 rel...ecS froa
the .ite, includift9 evaluation to a downwind ruident a.
part of an a9ricultural future .e.
- Incidental 1nge.tion of .vface 8Oil,
- Il'9ution of cp:oundVater,
. - Inhalation of ~latile. rel..88d dur1n9 in400r .u of
9roundvater, .
- D8r881 expo.uru. to 9roundvater.
~ ~.
.
-------
.aft SgstDIIS. /Nt.
TAiLE 5 SUtOWlY OF ESTIMATED CAlCINOOD"1C UB - CUlUtD"'I POPULATIONS
Expo..d Expo.ure Expo.ure total Exce..
PopulaUon Point . Medium Ex1Io.ure Route Cancer Ri.k
Dirt-bike rider Site Soil IDle.tioD 21-06
Air Inhalation - Particulate. 2£-06
1Dha1ation - VOC. 21-08
Total 4E-
-------
. ...-.-----.--.----..
nfr SgstelllS. )H(.
tABLE 6 StlQWlY OF ESTDtATED CAlCINOGEKlC RisK -
m.l'OTHETICAL FUTURE IESIDENtlAL POPULATIONS
Exposed Expo£ure 1:.xposun Total £Xc...
PopulaUon Point Medium Ezpo.ure llouU Cancer ll1.k
lle.id.nt On Landfill:
Add t BOlle GroundwaUr In.e.Uon 1E-01
Iahalation - VOC. 4£-04
Danal 1£-01
5011 Inl..tion SE-05
Air lDhalation - Particulat.. 1E-07
IDbalacion - VOC. 8£-07
Tocal ' 2£-01
ChUd BOlle Grouiuiwaur In.e.cion 6E-02
lahalation - VOC. 2£-04
Dena1 6E-01
Soil In...tion 4E-05
Air Inhalation - 'articulate. 1E-07
Inhalation - VOC. 2£-06
total 1£-01
lleddent South of Landfill - Shallow Groundwater:
Adult BOII8 Groundwaur In.e.tion 4E-G3
Inhalacion - VOC. 6E-05
D.nal 1E-04
5011 In.e.tion 6E-04'
total 5R3
Child BOlle Groundwaur Inle.tion 2E-93
Inhalation - VOC. 4E-05
Denal 1E-03 '
soil Iqe.tion 4E-04
total 3E-03
..dd.nt Soutb of LaDdfi1l - D.ep Grouadwater:
Adult Bou Groundwater lnl..cion 4E-03
lDbalac10n - we. 6£-05
Denal 11-04
5011 lnl"tion 61:-04
total 1R3
Child a.. GRunclvatn Iq.nioD 2£-03
lnbalation - voc. 3£-05
D.nal 1£-03
5011 Inl..tiOD 4E-04
total 3£-03
. -
-------
.ale SgstDlIS. /J
TAiLE 7 SUMMAIY 01 IORCAlCDOGER1C lliB - CII'UD"T POPt.'UTlONS
Expo..d Expoaun tzpo.un baud Index
P01lul.tlon Point M.dlum £x1Io.ur. Ioute SubchroD1c Chro~lc
D1Tt-bike Site So11 ID...cloD _(a> 7E-03
Rider Air IDhalatlon ~ 'artlculat.. 2£-01
'iDbalat1on - Voc. - 3£-05
- 1Ri
toeal
Wader Quarry Surface Iq.atloD 5£-04
Pit \iat.r DeNAl 41-<14
Sed188Dt ID...tlon lE-03 -'
'Io tal U-03 -
"'aciar Pond. Surfac. In...cion 3E-04
"'at.r D.l'8&l 51-04
Sadia.nt ID...clon 2E-04 -
toeal 11-03 -
Dovavlnd off-.lt. r..ld.nc:
Adult 808. Air IDbalatlon - Partlculat.. lE-ol
- VolaUl.. - lI-03 '
- ii=Oi
toeal
Ch11d 808. Air Iabalatlon - 'artlculat.. 61-02
- VolatU.. lE-02 -
71-02 -
Total
ia> Ixpo.ur. DOC .valu.~.d for ebi. population.
-------
nit sgsttlllS. /It,
TABLE 8 SUMMARY OF NONCAllCI);OGE!I"1C IllSl -
HtPOTHETlCo\L MUlE RI5nnrn.u. PCPloUTIO);5
,
!apo.ad Exp08UT.
Population Point
Ra.idant On Landfill:
Adult 808a
Ch11d
H08a
Expo.ure
I'.adium
C rOUl\dva tar
5011
Air
Groundvacar
5011
Air
Expo.ur. Routa
IDlascioD
labalation - Voc.
Denal
IDle.tion
IDbalation - Particulate.
lahalation - VOC.
Total
IDI..ti0D
IDbalat10D - VOC.
DenIAl
IDle.UoD
IDbalatioD - PaTt1culat..
IDbalat10n - voc.
South of LaDdfill - Shallow GToundwateT:
6088 GToundvat8r IDle.tion
IDbalatioD - VOC.
Denal
ID.e.tion
I8ddent
Adult
Ch11d
8088
Soil
CroundvataT
5011
In.e.tioD
IDbalation - VOC.
Danal
IDle. t ion
South of LaDdf11l - Daep Groundwater:
8088 GToundvat8T ID.a.tioD
IDbalaUOD - VOC.
Danal
IDla.UoD
"ddaDt
Adul t
Child
IIa88
So 11
Groundwatar
5011
IDla.tioD
IDbalaUon - VOC.
Danal
ID.a.tiOD
Total
Total
Total
toul
Total
Halard lndax (a)
5E+02
21+00
2£+01
2£-01
11-02
1!-o3
~
91+02
4£+00
U+02
8E-ol
71-03
1£-02
n:HS3
9£+00
2!-ol
81-01
11-01
rmT
21+01
2£-01
31+00
51-01
1mi
4!+OO
21-01
n-ol
11-01
~
91+00
Za-ol
41+00
51-01
'Ii+ri
(a) Bazard iAdax 18 .ullchronlc for chlld population. aDd cbronlc for aU
otbars.
-------
4.
Risk Characterization
For each potential receptor, site-specific contaminants from
all relevant routes of exposure were evaluated. Both non-
carcinogenic health effects and carcinogenic risks were
estimated.
a.
Non-Carcinoqenic Health Risks
Reference doses (RfDs) have been developed by u.s. EPA for
indicatinq the potential for adverse health effects from
exposure to chemicals exhibitinq non-carcinoqenic effects.
RfDS, which are expressed in units of mg/kq-day, are
estimates of averaqe daily exposure levels for humans,
includinq sensitive individuals. Estimated intakes of'
chemicals from environmental media (e.q., the amount of a
chemical inqested from contaminated drinkinq water) can be
compared to the RfD. RfDs are derived trom human
epidemiological studies or animal studies to which
uncertainty factors have been applied (e.q., to account for
the use of animal data to predict effects on humans). These
uncertainty factors help ensure that the RfD. will not
underestimate the potential for adverse non-carcinoqenic
effects to occur.
The Hazard Index (HI), an expression of non-carcinogenic
toxic ettects, measures whether a person is bein9 exposed to
adverse levels of non-carcinoqens. The HI provides a useful
reference point for qauqinq the potential significance of
multiple contaminant exposures within a single medium or
acro.. multiple media. The HI for non-carcinoqenic health
risk. is the sum of all contaminant. for a given scenario.
Any Hazard Index value greater than 1.0 suqgests that a non-
carcinoqen potentially pre.ent. an unacceptable health risk.
b.
Carcinoqenic Health Risk.
Cancer potency factors (CPFs) have been developed by EPA's
carcinoqenic Assessment Group tor estimating excess litetime
cancer risk. a..ociated with expo.ure to potentially
carcinogenic chemicals. CPl., which are expre..ed in units
of (8CJ/kg-dayrl, are mUltiplied by the e.timated intake of
a potential carcinogen, in mg/kg-day, to provide an upper-
bound e.timate of the exce.. lifetime cancer ri.k associated
with exposure at that intake level. The term "upper bound"
retlect. the conservative e.timate ot the ri.k. calculated
from the CPF. Use of this approach make. underestimation of
the actual cancer risk hiqhly unlikely. Cancer potency
factors are derived from the re.ult. of human
epidemioloqical studies or chronic animal bioassays. The
exce.s lifetime cancer risk. are' the sum of all excess
10
-------
cancer lifetime risks for all contaminants for a qiven
scenario.
Exces. Lifetime Cancer Risks are determined by multiplyinq
the intake level by the cancer potency factor for each
contaminant of concern and summinq across all relevant
chemicals and pathways. These risks are probabilities that
are generall¥ expressed in scientific notation
(e.q. 1 X 10). An excess lifetime cancer risk of 1 x 10~
indicate. that a person's chance of contractinq cancer as a
result of site related exposure averaqed over a 'O-year
lifetime may be increased by as much as 1 in one million.
The U.S.EPA qenerally attempts to reduce the excess lifetime
cancer risk at Superfund sites to a ranqe of 1 x 10~ to 1 X
10~' (1 in 10,000 to 1 in one million), with an emphasis on
the lower end (1 x 10~) of the scale. Tables 5 and 6
summarize the excess lifetime cancer risks and HI values
estimated for the current land-use scenario, respectively.
Tables' and 8 summarize the excess lifetime cancer risks
and HI values estimated for the future land~use scenario
respectively, at the Himco Site.
c.
Characterization of Lead
The U.S. EPA evaluates non cancer risks from lead by a
different method than those described above. The Aqency
believes that an acceptable approach is to estimate the
likely effects of lead exposure on the concentration of lead
in the blood. The Uptake/Biokinetic model was used to
predict blood lead levels for the scenarios evaluated at
this site. The U.S. EPA has identified 10 uq/L of lead in
the blood as the level' of concern for health effects in
children. Of all the scenarios evaluated, there is a cause
for concern if the qroundwater beneath the landfill is used
a. . drinkinq water source.
5.
Risk Summary'
A major threat i. the miqration of the plume off-.ite at
4atectable level. of concern. Some contamination above MCLs
'haa been found in wells south and .outheast of the landfill
that either was not found or exceeded levels in background
well. and that may be attributable to site contamination.
The potentiaf exce.s lifetime cancer risk posed by the site
exceeds the acceptable risk ranqe of 1 X 10 ~ to 1 X 10 ~
principally from the use of contaminated qroundwater under
the future use scenario. Risk. from inqestion, dermal
contact and inhalation of volatiles from this qroundwater
pre.ent carcinoqenic risks in the ranqe of 1 X 10 -I. South
of the landfill, downqradient, the estimated excess cancer
11
... .~-- ._~ ---
-------
risks to a future resident are approximately 5 X 10 .3. The
hazard index for humans interactinq with the site exceed the
acceptable hazard index of 1.0. For future use of the
qroundwater under the landfill, the hazard index values are
approximately 500 to 1,000.
Some of these risks are caused in some part by chemicals
which could be present at levels close to levels found in
background wells (that is, wells located upqradient of the
site). These chemicals include arsenic, antimony and
beryllium. The samplinq results do not clearly indicate
whether or not the site is actually contributinq more of
these chemicals to the qroundwater; however, even if the
risks due to these possible background chemicals were not
included in the risk estimates, there still are risks trom
other chemicals that indicate the qroundwater beneath the
landfill should not be used as a drinkinq water source.
In addition to groundwater, there is an estimated
cancer risk of 4 to 6 X 10 ~ to a future resident
south of the landfill where Polynuclear Aromatic
Hydrocarbons (PARs) were detected in the soil.
excess
livinq
6.
Environmental Risks
An ecoloqical risk assessment was conducted to characterize
the bioloqical resources at the site and adjacent habitats,
and identify actual and potential impacts to these resources
associated with releases of hazardous substances from the
site.
contaminants present in the soil where the prairie
communities are located are unlikely to pose adverse impacts
to resident species of plants and animals. The qreatest
hazard to resident orqanisms occurs in the south/southeast
area of the site where contamination is hiqher and more
varied. This area is hiqhly disturbed and unlikely to
support ecologically siqnificant populations. Small mammals
are likely to inhabit this area and maybe exposed to
contaminants. Other areas of the site are unlikely to pose
a siqnificant threat of adverse effects to exposed
organisms. The potential exposures of ecological concern
are summarized in Table 9.
G.
RATIONALE FOR FURTHER ACTION
Actual .or threatened releases of hazardous substances from this
site, if not addressed by implementation of the response action
selected by this ROD, may present an imminent and substantial
endangerment to public health, welfare, or the environment.
Therefore, based on the findings in the RI report and the
12
~ .. --.'... ,-. . .
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.
TABLE
9
,
EXPOSURE SCENARIOS FOR ECOLOGICAL POPULATIONS
HIMCO DUMP SUPERFUND SITE
ELKHART, INDIANA
1992
Relative
'oteDtial
Mapitude
Exposure J»OiDt Esposed Populatioa Exposure Activity of EKposure
L-PODd, Small BeDthic invertebrates Direct uptake, feediag High
PODd aDd Quarry
PODd FISh Direct uptake, feediag High
PhytoplaaktOD Direct uptake High
ZooplaaktOD Direct uptake, feediag High
ResideDt shorebirds 1agesti0D of water, soil, Low to
aDd sedimeDt; feediag Moderate
Migratory waterfowl IDgestiOD of water, soil, Very Low
and sedimeDt; feediag
Terrestrial wildlifc 1agesti0D of watcr. soil, Low to
(indudiag avian) aDd scdimeDt; fecdiag Modcrate
Aquatic macrophytcs Directuptakc High
Aquatic orgaaisms Direct uptake, fcediag Low to
aposed to rUDoff Moderatc
from watershed
Terrestrial Terrestrial plants Growth in CODtaDUDated High
I..ocabODS soil; uptake
Terrestrial invertebrates 1apsti0D of CODtamiaated Very Low to
aDd wildlife (indudiag water aad soil; direct High
burrowiag aDimals, soil CODtact with COPI.milt.ted
iDvertcbrates, a~ soil; CODSumpUOD of
plC4Iators, e.g., eagles) COI.'I.milt.~ed p~ts.lDd
aaimals
'WedaDd Wedud wpiatiOD Direct u~e . Moderate to
expoICd to rUDoff aDd High
~I.min.ted soil
A/R./HIMCO/AS6
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....- .-._-----"'---~' -.. ..
discussion above, a Feasibility study (FS) was performed to focus
on the development of alternatives to address the threats at the
site. The FS report docum.nts the evaluation of the magnitude of
site risks, site-specific applicable or relevant and appropriate
requirements, and the requirements of CERCLA and the NCP in the
derivation of remedial alternatives for the Site.
H.
DESCRIPTION OF ALTERNATIVES
Although the NCP reaffirms u.S. EPA's preference for permanent
solutions to Superfund site problems through the use of treatment
technologies, the preamble to the NCP contemplates that many
remedial alternatives may be impractical for certain sites due to
severe implementability problems or prohibitive costs (e.g.,
treatment of the entire contents of a large landfill). . Since the
Himco site contains a 58 acre landfill, u.S. EPA believes that
treatment of the landfill contents is impracticable because of
severe implementability problems, danger to workers and nearby
residents, and prohibitive costs; therefore, the FS was directed
at the evaluation of containment rather than treatment of the
source material. Source control alternatives range from no
action to capping with leachate collection and treatment.
Because the target risk level of one in 10,000 (1 X 10 ~ for
carcinogenic risk and HI of 1 for noncarcinogenic risk) is
currently exceeded in background groundwater samples, the NCP
target risk levels cannot be specified for the groundwater
downgradient of the Himco site. Additionally, RI data do not
conclusively indicate that groundwater outside the boundaries of
the contaminated areas is currently being impacted by the site'
contaminants; therefore, at this time a groundwater remedy and
cleanup standards have not been developed for this site.
A groundwater monitoring program is a component of each
alternative except the no action alternative~ Groundwater
monitoring has been incorporated in the alternatives to evaluate
the effectiveness of the remedy. The FS has established
contamination levels for contaminants of concern which would
trigger an additional groundwater investigation if the remedy
fails and those levels are reached.
All caps would be designed to minimize any adverse impact to the
wetland, delineated during the RI.
Alternative 1 - .0 Action
'The NCP requires that a No Action alternative be evaluated' at
every site to serve as a baseline tor comparison against the
other cleanup alternatives. It assUmes that no corrective action
will be taken at the site. It has no cost or operation 'and
maintenance associated with it. It does not provide any long-term
13
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effectiveness and permanence; nor does it provide a reduction of
toxicity, mobility, or volume throuqh treatment.
Alternative 2 - Contaiuaent by Xeans of a Solid Wast. Cap; Active
Landfill Gas Collection and Treataent; Groundwater Monitorinq;
and Institutional Controls
Alternative 2 includes a single barrier, solid waste cap to
contain the landfill waste mass and the contaminated surface soil
in the construction debris area and in an area immediately south
of the landfill, and an active landfill qas collection and
treatment system with vapor phase carbon adsorption. A
qroundwater monitorinq proqram will be implemented and
institutional controls will be placed on the site by means of
fencinq, access restrictions, deed restrictions, and qroundwater
use restrictions. The primary components, of this alternative
include the followinq:
CaD Construction
The entire landfill waste mass and the contaminated surface soil
in the construction debris area and in the area immediately south
of the landfill will be capped. Site preparation and layout will
be completed to re-route surface water drainaqe away from the
capped area. The cap will consist of an 18-inch veqetated soil
layer, a 6-inch sand drainaqe layer, and a 2-foot thick, low
permeability clay layer. The veqetative soil layer will be
seeded, if possible, with the current on-site plant species to
preserve the uniqueness of the prairie assemblaqe at this site.
An additional layer of soil (buffer) of approximately 2.15 feet
will be' laid over the existinq landfill to attain a 4 percent
qrade required by the State of Indiana and to facilitate
drainaqe.
Groundwater Monitorinq
A qroundwater monitorinq proqram will be implemented to monitor
qroundwater quality downqradient of the site and to evaluate if
the remedy is effective in protectinq the site qroundwater from
adverse impacts by site contaminants.
Landfill Gas
An active landfill qas collection system will be located in a
qrid network throuqhout the landfill. The off-qas from the
landfill will be treated by means of a vapor phase carbon system
if landfill qas characterization studies indicate VOC emissions
exceed ARARs. The spent carbon would be tested by TCLP to '
determine if it is hazardous by characteristic, and then manaqed
. accordinqly. If any methane qas is qenerated, creatinq explosive
conditions, an enclosed qround flare system will be implemented
to burn it.
.
14
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Institutional Controls
Institutional controls will be implemented, which include
installation of a fence around the landfill and contaminated
soils covered by the cap; and deed restrictions limitinq the
site's future land use as well as restrictions on qroundwater use
in the site vicinity.
The estimated costs for this alternative are:
Capital Cost: $7,539,000
Annual O&M Cost: $210,000
Total Present Worth: $10,429,000
Alternative 3 - containment by Meana of a sinqle Barrier, Solid
Waate Cap; Active Landfill Gas Collection and Treatment; Leachate
collection and Off-Site TSDF Diaposal; Groundwater Monitorinq;
and Institutional Controls
Alternative 3 is the same as Alternative 2 with the addition of a
leachate collection system and off-site disposal.
Leachate Collection svstem
A leachate collection system, consistinq of vertical wells placed
in the landfill to extract leachate qenerated in the landfill,
will be constructed. six hundred eiqhty wells, spaced S6 feet
apart will be installed in the landfill. The collected leachate
will be transported by means of an interconnectinq pipinq system
to a central collection point, then transported for treatment and
disposal to a licensed, treatment, storaqe and disposal (TSDF)
facility. compliance with Indiana state Codes requlatinq
disposal of wastewater would be required.
capital Cost: $13,628,000
Annual O&M Cost: $982,000
Total Present Worth: $27,140,000
Alternative o. - containment by .eans of a composite Barrier,
solid .aste cap; Active collection and Treatment of Landfill Gas;
Groundwater Konitorinq; and Institutional controls
This alternative is similar to alternative 2, except the cap is a
composite barrier, solid waste cap. The cap structure is the
same as alternative 2 except that upon the 2-foot clay layer and
under the 6-inch sand drainaqe layer, there will be a 40
millimeter, hiqh density polyethylene (HDPE) flexible membrane
liner. The composite cap provides an added level of landfill gas 0
containment and qreater control of infiltration into the waste
mass, over the sinqle barrier cap. The composite cap qreatly
reduces the need for a leachate collection system.
lS
t
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capital Cost: $8,931,000
Annual O'M Cost: $210,000
Total Present Worth: $11,821,000
I.
SummarY of ComDarative Analvsis of Alternatives
In accordance with the National oil and Hazardous Substances
Pollution continqency Plan (NCP), the relative performance of
each alternative is evaluated usinq the nine criteria, Title 40
of the Code Federal Requlations (40 CFR) Section 300.430(8) (9)
(iii), as a basis for comparison. An alternative providinq the
"best balance" of trade-offs with respect to the nine criteria is
determined from this evaluation.
The followinq two threshold criteria, overall protection of human
health and the environment, and compliance with Applicable or
Relevant and Appropriate Requirements (ARARs) are criteria that
must be met in order for an alternative to be selected.
1.
Overall Protection of Human Health and the Environment
Overall protection of human health and the environment
addresses whether a remedy eliminates, reduces, or controls
threats to human health and to the environment.
The major exposure pathways of concern at the site are from
inqestion, inhalation, and direct contact with the landfill
waste mass and contaminated soils in the construction debris
area. The continued release of leachate into the
qroundwater aquifer and outside the landfill boundaries also
presents a risk to human health and the environment.
Environmental risk may result from the release of landfill
fuqitive dust into the air.
Alt.rnative 1 does not satisfy the requirement for overall
protection of human health and the environment.
Alternatives 2 and 3 provide protection to ,human "health and
the environment by reducinq risk by containinq the landfill
waste mass, and the contaminated surface soil in the
,construction debris area and in an area immediately south of
the landfill, with a sinqle barrier, solid waste cap and by
cOllecting and treating the landfill gas. With these
alternatives, human risk associated with exposure to the
wastes in the landfill and the contaminated surface soil in
the construction debris area and in an area immediately
south of the landfill is theoretically eliminated.
Additionally, risk associated with release of the leachate
into the groundwater or outside the landfill boundaries i.
reduced. .
Alternative 3 provides further reduction of risk with the
extraction and off-site treatment and disposal'of leachate
~
16
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from the landfill. This reduces the potential for release
of contaminants into groundwater or other media outside the
landfill boundaries. Alternative 4 provides a greater
reduction in risk than Alternatives 2 and 3 because the
composite cap provides an added level of landfill .gas
containment and greater control of infiltration into the
waste mass, over the single barrier cap, thereby minimizing
the potential release of leachate into the groundwater and
other media outside of the landfill boundaries (the
composite cap greatly reduces the need for a leachate
collection system).
2.
compliance with Applicable or Relevant and Appropriate
Requirements
This criterion evaluates whether an alternative meets ARARs
set forth in federal, or more stringent state, environmental
. standards pertaining" to the site or proposed actions.
Because the No Action alternative does not involve
conducting any remedial action at the site, no ARARs
analysis is necessary for Alternative 1. Alternatives
and 4 are expected to be in compliance with ARARs.
2, 3,
3.
Long-Term Effectiveness and Permanence
This criterion refers to the ability of an alternative to
maintain reliable protection of human health and the
environment over time. The primary focus of this evaluation
is the extent and effectiveness of controls that may be
required to manage the risk posed by treatment residuals
and/or untreated waste.
Alternative 1, the No Action alternative, provides no long-
term effectiveness and would result in continuation of the
elevated risk levels that currently exist at the Himco site.
Alternatives 2 and 3 provide long-term effectiveness and
permanence by containing the landfill waste mass, and the
contaminated surface soil in the construction debris area
and in an area immediately south of the landfill, with a
single barrier, solid waste cap. The cap will reduce
ingestion, inhalation, and direct contact with contaminated
materials and will reduce infiltration of precipitation into
the waste mass which reduces leachate generation, thereby
reducing the potential for off-site groundwater
contamination. Alternative 3 further reduces risk with the
leachate collection system; however, because groundwater is
hydraulically connected with the landfill waste, there is
. uncertainty as to the effectiveness of collecting the
leachate. Alternatives 2 and 3 also provide long-term
effectiveness and permanence by implementing institutional
17
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controls to maintain the cap's inteqrity arid restrict
qroundwater use in the site vicinity.
Alternative 4, like Alternatives 2 and 3, provides lonq-term
effectiveness and permanence throuqh containment and
reduction of infiltration and by implementinq institutional
controls to maintain the cap's inteqrity, as well as to
restrict qroundwater use in the site vicinity. The
composite barrier solid waste cap in Alternative 4 further
reduces infiltration, which reduces the qeneration of
leachate, thereby providinq a qreater reduction in risk and
in the potential for off-site qroundwater contamination.
4.
Reduction of Toxicity, MObility, or Volume throuqh
Treatment .
This criterion evaluates treatment technoloqy performance in
the reduction of chemical toxicity, mobility, or volume.
This criterion addresses the statutory preference for
selectinq remedial actions which include, as a principal
element, treatment that permanently and siqnificantly
reduces the volume, toxicity, or mObility of the hazardous
substances, pollutants, and contaminants.
Alternative 1 provides no reduction in toxicity, mobility,
or volume. Alternatives 2 throuqh 4 provide a sliqht
reduction in toxicity or volume in VOCs from landfill qas
collection. Alternative 3 provides an added marqinal
reduction in toxicity and volume throuqh the leachate
collection. Alternatives 2, 3, and 4 provide reduction in
mobility by reducinq leachate qeneration in the landfill.
The liner system in Alternative 4 provides a qreater
reduction in the leachate qeneration rate than that in
Alternatives 2 and 3, further reducinq mobility of
contaminants in the landfill.
5.
Short-Term Effectiveness
Short-term effectiveness considers the time to reach cleanup
objectives and the risks an alternative may pose to site
workers, the community, and the environment during remedy
implementation until cleanup qoals are achieved.
Potential risks from Alternatives 2, 3 and 4 to the
community during implementation are from exposure to
airborne dust and orqanic vapors from the waste mass and
leachate. Workers employed in the construction of the qas
collection system, the leachate collection system and the
cap may be exposed to the waste mass and leachate material.
All the alternatives, except Alternative 1, include measures
to minimize the short-term impacts durinq construction, such
as dust control and the use of safe work practices.
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6.
Implementability
This criterion addresses the technical and administrative
feasibility of implementing an alternative, and the
availability of various services and materials required for
its implementation.
All the alternatives are implementable and can be readily
constructed with technology and materials presently
available. The composite barrier cap in Alternative 4 will
take a little more time for installation than the single
barrier cap in Alternatives 2 and 3. operation of
Alternative 3 will be more difficult because it includes a
leachate collection and storage system and requires periodic
disposal of leachate at an off-site TSDF.
7 .
Cost
This criterion compares the capital, O&M, and present worth
costs of implementing the alternatives at the site. Table
10 shows the Cost summary.
8.
state Acceptance
The State. of Indiana is in agreement with the selection of .
Alternative 4 for remediation of the Himco Dump site and has
provided u.s. EPA with a letter of concurrence.
9.
community Acceptance
Community concerns have been thoroughly reviewed and are
addressed in the attached Responsiveness summary.
J.
The Selected Remedv
Based upon considerations of the requirements of CERCLA, the NCP
and balancing of the nine criteria, the U.S. EPA has determined
that Alternative 4, a composite Barrier, Solid Waste Cap; Active
Collection and Treatment of Landfill Gas; Groundwater Monitoring;
and Institutional controls, is the most appropriate remedy for
the Himco Dump Site.
The components of the selected remedy are as follows:
A composite barrier, solid waste cap with an area equal
to approximately 58 acres, consisting of: an 18-inch
vegetated soil layer; a 6-inch sand drainage layer; a
40 millimeter, high density polyethylene (HDPE)
flexible membrane liner; a 2-foot thick, low
permeability clay layer and an additional layer of soil
(buffer) of approximately 2.15 feet laid over the
existing landfill to attain the State of Indiana
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TABLE 10
COST SUMMARY
Himeo Dump Superfund Site
Elkhart. lodiana
Capital Annual Tntill Present
Alternatives Cost O&M Cost Worth Cost.
I". No Action SO $0 SO
2. Single Barrier Cap, Gas Collection'" Treatment, S7,539,000 $210,000 $10,429,000
Groundwater Monitoring, '" Institutional Control
3. Single Barrier Cap, Gas Collection'" Treatment. . $ 13,628,000 $982,000 $27,140,000
Leachate Collection System, Groundwater Monitoring,
'" Institutional Control
4. Composite Barrier Cap, Gas Collection'" Treatment, S8,93 1 ,000 $210,000 $11,821,000
Groundwater Monitoring, & Institutional Control
. Present worth cost based on interest(i) =6% and 30 years for O&M (see Tables 4-1 through 4-4).
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required 4 percent grade and to facilitate drainage.
Institutional controls including fencing, deed
restrictions limiting the land use of the site, and
groundwater use restrictions.
An active landfill gas collection system including a
vapor phase carbon system to treat the off-gas from the
landfill.
An enclosed ground flare system will be implemented if
landfill gas characterization studies indicate VOC
emissions exceed ARARs.
A groundwater monitoring program designed to detect
changes in concentration of hazardous constituents in
the groundwater and to detect the presence and
concentration of site related contamination in drinking
water wells near the site.
The groundwater monitoring program shall continue for
,30 years. Samples shall be analyzed for target
compound list (TCL), VOCs and target analyte list (TAL)
metals.
Mitigative measures will be taken during remedy
construction activities to minimize adverse impacts to
the wetland.
K.
statutory Determinations
U.S. EPA's primary responsibility at superfund sites is to
undertake remedial actions that protect human health and the
environment. Section 121 of CERCLA has established several other
statutory requirements and preferences. These include the
requirement that the selected remedy, when completed, must comply
with all applicable, relevant and appropriate requirements
("ARARs") imposed by Federal and State environmental laws, unless
the invocation of a waiver is justified. The selected remedy
must ,also provide overall effectiveness appropriate to its costs,
and use permanent solutions and alternative treatment
technologies, or resource recovery technologies, to the maximum
extent practicable. Finally, the statute establishes a
preference for remedies which employ treatment that significantly
reduces the toxicity, mobility or volume of contaminants.
The selected remedy will satisfy the statutory requirements
e~tablished in Section 121 of CERCLA, as amended by SARA, to
protect human health and the environment, will comply with ARARs
, (or provide grounds ~or invoking a waiver), will provide overall
effectiveness appropriate .to its costs, and will use permanent
solutions and alternate treatment technologies to the maximum
20
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extent practicable. Treatment is not a component of the selected
remedy because an attempt to treat the hazardous substances
present at the site in soils and leachate would not provide a
sUfficiently significant additional decrease in risk presented by
the sit~ to justify the increased cost of attempting such
treatment.
1.
Protection of Human Health and the Environment
Implementation of the selected remedy will protect human health
and the environment by reducing the risk of exposure to hazardous
substances present in surface soils and leachate at the site.
An adequate final cover for the site will reduce the risk of
exposure to hazardous substances present in soil at the site, and
will also reduce the rate of infiltration by which precipitation
passes throuqh the contaminated soil and maintain that reduction
over time. By reducing the rate of infiltration, the final cover
will also reduce the rate of leachate generation in the landfill;
therefore, the final cover will also reduce the risk that
hazardous substances, pollutants, and contaminants present in the
leachate will migrate and contaminate the aquifer. Groundwater
monitoring will be required to provide early warning against the
risk that the hazardous substances present in the leachate may
migrate and contaminate the aquifer. Institutional controls
~ill be imposed to restrict uses of the site to prevent exposure
to hazardous substances and contaminants in the soil and the
leachate at the site. No unacceptable short-term risks will be
caused by implementation of the remedy. The community and site
workers may be exposed to dust and noise nuisances during
construction of the final cover. Mitigative measures will be
taken during remedy construction activities to minimize impacts
of construction upon the surrounding community and environs.
Ambient air monitoring will be conducted and appropriate safety
measures will be taken if contaminants are emitted. .
2.
Compliance with ARARs
The selected remedy will comply with all identified applicable or
relevant and appropriate federal requirements, and with those
state requirements which are more stringent, unless a waiver is
invoked pursuant to Section 121(d)(4)(B) of CERCLA. The ARARs
for the selected remedy are listed below:
A.
Federal ARARs
Chemical-SDecific Reauirements
Chemical-specific ARARs requlate the release to the environment.
of specific substances. having certain chemical characteristics.
. Chemical-specific ARARs typically determine the standard for
clean-up at a site. . .
21
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Resource Conservation and Recoverv Act CRCRA)
As the hazardous wastes at this site were placed prior to the
effective date of the requlations, the chemical-specific
requirements of RCRA are not applicable. As the leachate from
the waste mass is highly contaminated by hazardous substances
similar to RCRA hazardous substances, the chemical-specific
requirements of RCRA are relevant and appropriate. 40 CFR 141
requires that ground water used as drinking water meet Maximum
contaminant Levels ("MCLs") for contaminants of concern.
Safe Drinkina Water Act
40 CFR 141
Federal Drinking Water Standards promulgated under the Safe
Drinking Water Act ("SDWA") include both Maximum contaminant
Levels ("MCLs") and, to'a certain extent, non-zero Maximum
contaminant Level Goals ("MCLGs"), that are applicable to
municipal drinking water supplies servicing 25 or more people.
At the Himco Dump Site, MCLs and MCLGs are not applicable, but
are relevant and appropriate, because the unconfined aquifer
below the site is a Class II aquifer which has been used by
residences bordering the site, is presently being used by
residences in the area surrounding the site and could potentially
be used in the future as a drinking water source. '
The National contingency Plan ("NCP") at 40 CFR 300.430 (e) (2)
(i) (B) provides that MCLGs established under the Safe Drinking
Water Act that are set at levels above zero, shall be attained by
remedial actions for ground waters that are current or potential
sources of drinking water. The point of compliance for federal
drinking water standards is at the boundary of the
solidified/stabilized waste, because this is the point where
humans could potentially be exposed to contaminated groundwater.
Because this site will have a final clay cover, the point of .
compliance will be at the boundary of the final cover. Ground
water monitoring wells will be installed at the point of
compliance to ensure that any release of contaminated leachate
from the site which could adversely affect the aquifer i.
detected at the earliest possible stage. Existing ground water
wells in the, aquifer will also be monitored, and additional wells
may be drilled and monitored, if necessary.
Location-Soecific Reauirem.nts
Location-specific ARARs are those requirements that derive from
the physical nature of the site's location and features of the
local geology and hydrogeology such as wetlands and fl~odplains.
'. -
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Resource Conservation and Recoverv Act ("RCRA")
Executive Orders 11988 11990, 40 CFR Part 6, Appendix A
Since the RI has identified wetlands adjacent to the site, the
action must be carried out in such a way as to prohibit discharge
of dredged or fill material into wetlands without a permit, avoid
adverse effects, minimize potential harm, and preserve and .
enhance wetlands, to the extent possible. Executive Order 11990
(protection of Wetlands) is an applicable requirement. Executive
Order 11990 requires that actions taken at the site be conducted
in a manner minimizing the potential for destruction, loss, or
degradation of wetlands.
Wetlands will be monitored and evaluated. ARARs for wetlands.
will be met through the continued evaluation of the wetlands, and
if necessary, implementation of a plan to limit degradation, or
restore the wetlands.
Action-SDecific Reauirements
Resource Conservation and Recoverv Act ("RCRA")
Landfills
40 CFR 264.310
This regulation requires the installation of a final cover to
provide long-term minimization of infiltration. This regulation
also requires 30-year post-closure care and ground-water
monitoring. The Regional Administrator may revise the length ot
post-Closure care period pursuant to 40 CFR 264.117(a) (2) (i) if
he finds that a reduced period is sufficient to protect human
health and the environment; or extend the length of the post-
closure care period pursuant to 40 CFR 264.117(a) (2) (ii) if he
finds that the extended period is necessary to protect human
health and the environment.
Although the hazardous waste in this landfill was placed before
the effective date of the requirements, and therefore, this
regulation is not applicable; it is nevertheless clearly
appropriate in light of the wastes similar or identical in
chemical structure to RCRA hazardous wastes that pose the threats
which thi8 action will be designed to addreS8. This regulation
establishe8 8tandards for the final cover and requires compliance
with the regulations which govern post closure care set forth at
40 CFR 264.117~120.
Post Closure Care
40 CFR 264.117(a) (1)
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While the requirements for post closure care set forth at 40 CFR
262.117 through 264.120 are not applicable to this site, the
presence of hazardous substances similar to RCRA hazardous wastes
in the dump make several of these regulations relevant and
appropriate. This includes the requirement for maintenance and
monitoring of the waste containment systems for thirty years.
40 CFR 264.117(c)
The remedy selected for this site requires u.s. EPA to restrict
post-closure use of this property as necessary to prevent damage
to the cover. Post closure use of the property must never be
allowed to disturb the integrity of the cover, the liner, or any
other component of the containment system, or the function of the
facility's monitoring systems, unless the Regional Administrator
finds that the disturbance is necessary to the proposed use of
the property and will not increase the potential hazard to human
health and the environment, or the disturbance is necessary to
reduce a threat to human health and the environment
40 CFR 264.228(b)
40 CFR 264.310(b)
It will be necessary to prevent run-on and run-off from damaging
the cover.
Closure with Waste in Place
40 CFR 264.228(a) (2)
40 CFR 264.258(b)
These regulations require the elimination of free liquids by
removal or solidification, and the stabilization of remaining
waste and waste residue to support cover. Because the RCRA .
hazardo~s waste in this landfill was placed before the effective
date of the regulations, they are not applicable, but may be
considered relevant and appropriate. .
Clean Air A9t
40 CFR 50 and 52
The Clean Air Act and the regulations cited above require that
select types and quantities of air emissions be in compliance
with regional air pollution control programs, approved state
Implementation Plans ("SIP"s) and other appropriate federal air
criteria. The selected re~edy involves installation of a gas
collection system which may release contaminants or particulates
into the air. Emission and technology requirements promulgated~
under this act are relevant and appropriate, including provisions
of the state of Indiana's SIP. ..
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B.
state ARARs as Identified by the state of Indiana
- Wetlands Protection through the state of Indiana Water Quality
Surveillance Standards Branch and the Indiana DNR Division of
Water Requirements
- Ambient Air Quality standards (Title 326 IAC Article 1-3)
- Indiana VOC ~ission standards (Title 326 IAC Article 2-1 and
8-1-6)
- Indiana fugitive dust control (Title 326 IAC Article 6-4)
- Indiana solid Waste Landfill Cover standards (Title 329 IAC
Articles 2-4, 2-14, 2-15 and 3.1-9
- Indiana Solid and HazardouS Waste Manaqement (Title 329 IAC
Article 2-21)
The remedy will attain the state standards listed above to the
extent that such standards are applicable, or relevant and
appropriate, promulgated. standards more strinqent than the
comparable federal standard.
3 ~
cost Effectiveness
cost effectiveness compares the effectiveness of an alternative
in proportion to its cost of providing environmental benefits.
Table 11 lists the costs associated with the implementation of
the selected remedy.
'J'ABLE 11
Total estimated costs for the selected remedy at t~e Himco Dump
site: .
4
Total
Canital cost
$8,931,000
Total
O&M. 30 Yr.
TQtal
fresent worth
Alternative
$2,890,000
$11,821,000
> .
The selected remedy for this site is cost effective because it
provides the greatest overall effectiveness proportionate to its
costs when compared to the other alternatives evaluated, the net
present worth being $11,821,000. The estimated cost of the
selected remedy is comparable with Alternatives 2 and 3, and
assures a high degree of certainty that the remedy will be
effective in the long-term due to the siqnificant reduction of
the mobility of the contaminants achieved through containment of
the source material ~nd the decrease in. leachate generation. The
addition of a leachate collection system would provide only a
25
...
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limited additional reduction of risk to public health and the
environment. The uncertain effectiveness of such a system, which
would be very difficult to implement, does not justify the
additional cost for this component.
utilisation of Permanent Solutiona and Alternative
Treatment TechDoloqie. or Reaource Recovery
Technoloqie. to the Kaximum Extent Practicable
The selected remedy represents the maximum extent to which
permanent solutions and treatment technologies can be used in a
cost-effective manner at this site. Of those alternatives that
are protective of human health and the environment and that
comply with ARARs, U.S. EPA has determined that the .elected
remedy provides the be.t balance in terms of long-term "
effectiveness and permanence, reduction of toxicity, mobility, or
volume of contaminants, short term effectiveness,
implementability, and cost, taking into consideration State and
community acceptance. "
4.
The installation and maintenance of a final cover for the
landfill, ground water monitoring, and restriction of site access
through installation of a fence and institutional controls, will
provide the most permanent solution practical, proportionate to
the coat.
s.
Preference for Treatment aa a Principal Bl..ent
Based on current information, u.s. EPA and the State of Indiana
believe that the selected remedy is protective ot human health
and the environment and utilizes permanent solutions and
alternative treatment technologies to the maximum extent
possible. The remedy, however, does not satisty the statutory
preference for treatment of the hazardoua substances present" at
the site as a principal element because auch treatment was not.
found to be practical or coat ettective.
26
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HIMCO DUMP
RESPONSIVENESS SUMMARY
This Responsiveness summary has been prepared to meet the
requirements of sections 113(k) (2) (iv) and 117(b) of the
comprehensive Environmental Response, Compensation and Liability
Act of 1980, as amended by the Superfund Amendments and
Reauthorization Act of 1986 (CERCLA), which requires the United
States Environmental Protection Agency (U.S. EPA) to respond
"...to each of the significant comments, criticisms, and new data
submitted in written or oral presentations" on a proposed plan
for a remedial action. The Responsiveness Summary addresses
concerns expressed by the pub~ic, potentially responsible parties
(PRPs), and governmental bodies in written and oral comments.
received by U.S. EPA and the State of Indiana regarding the
proposed remedy for the Himco Dump Site.
Overview
The Himco Dump site is a closed landfill located at County
Road 10 and the Nappanee street Extension in Cleveland Township,
adjacent to the City of Elkhart, Elkhart County, Indiana. The
site is located approximately two miles north of the st. Joseph
River which runs east-west through the City of Elkhart. The site
covers approximately 100 acres and is bounded on the north by a
tree line and a gravel pit pond; on the west by two ponds (an
L shaped pond called the "L" pond, and the small pond); on the
south by county Road 10 and private residences; and on the east
by Nappanee street Extension.
There is an abandoned gravel pit operation in the northeast
corner of the site. An old truck scale and concrete structures
are also present in this area. The gravel pit is filled with
water which is approximately 30 feet deep. Two' smaller and
shallower ponds, the L pond and the small pond, are on the west
side of the. site.
The Himco site was privately operated by Himco Waste Away Ser-
vice, Inc., and was in operation between 1960 and september 1976.
In 1971, the Indiana state Board of Health (ISBH) first identi-
fied the Himco site as an open dump. In early 1974, residents
along County Road 10 south of the Himco site complained to ISBH
about color, taste, and odor problems with their shallow wells.
Analyses of aix shallow wells along county Road 10, ranging in
depth from 20 to 30 feet, showed high levels of manganese.
Mr. Chuck Himes, the principal landfill operator, replaced th..e
wells with deeper wells ranging in depth from 152 to 172 feet
below ground surface. By mid-1990, the wells showed high concen-
trations of sodium which posed a chronic health threat to the
residents. By November 1990, municipal water service was
provided to those residents whose wells were affected and was
-------
financed by Miles Laboratories, Inc. and Himco Waste Service,
.Inc. In 1976, the landfill was closed.
In June 1988, the Himco site was proposed for the National
Priorities List (NPL) and in February 1990, was officially placed
on the NPL and desiqnated a Superfund site. The site RIfFS was
bequn in 1989 and completed in 1992.
Public Comment Period
A public comment period on the FS and Proposed Plan for this Site
was initiated on september 30, 1992 and was oriqinally scheduled
to run for 30 days. However, the Aqency received requests from
Potentially Responsible Parties to extend the comment period, so
in response to these requests, the comment period was extended.
throuqh November 30, 1992. A public meetinq was held on October
6, 1992 at the Municipal Buildinq in Elkhart, Indiana. At this
meetinq, representatives from u.S. EPA and IDEM presented the
Proposed Plan, answered questions, and accepted cQmments from the
public. Approximately 60 people were in attendance. Comments
received durinq the comment period are included in this
Responsiveness Summary.
The RI Report, the FS and the Proposed Plan for the Site were
made available to the public on September 30, 1992. These
documents are available in both the administrative record and
information repositories maintained at u.S. EPA offices in
Chicaqo, Illinois, the Elkhart Public Library and the Pierre
Moran Branch Library in Elkhart, Indiana.
Summarv of Comments
The public comments reqardinq the Himco Dump Site are orqanized
into the followinq two cateqories:
Summary of comments from local residents reqardinq the
FS and the Proposed Plan; .
Summary of comments from the PRPs concerninq the FS and
the Proposed Plan.
Many of the comments below have been paraphrased in order to
effectively summarize them in this document. The reader is
referred to the Administrative Record for this Site, located at
u.S. EPA offices in Chicaqo, Illinois and the Elkhart Public and
Pierre Moran Branch Libraries in Elkhart, Indiana. The
Administrative Record also contains a copy of the public meetinq
transcript. .
2
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comments from Residents of the Communitv Affected bv the Landfill
Comment: The majority of comments from the affected community
thank u.s. EPA for conducting the study. They want the site
cleaned without any more delays. Some of the comments support
our remedy; however, most of the comments reflect the community's
desire to excavate the landfill and avoid a "cover-up" remedy.
In addition, all but one comment from the community want the
leachate pumped and treated.
ReSDonse: It would be impractical to excavate the entire
landfill. The material would need to be treated in some way
which would be extremely expensive. After treatment, the
residual material would then need to be landfilled.
The leachate collection system was not recommended because, due
to the fact that the groundwater is hydraulically connected with
the landfill waste, and it is unlikely that the leachate wells
would effectively collect the leachate. In addition, 680
extraction wells would ne~d operation and maintenance and the
system would require perpetual pumping, treatment and disposal,
at substantial cost.
Comment: The proposed cap will not stop vertical infiltration.
What will happen when rain and snow melt is dumped on uncovered
areas?
ResDonse: The cap will greatly reduce vertical infiltration.
The composite liner provides an added layer of protection,
further minimizing infiltration into the landfill. The new cap
will prevent rain and snow melt from coming in contact with any
contaminated material and therefore, will not carry contamination
to uncovered areas.
Comment:
The groundwater is being contaminated. by the landfill.
ReSDonse: The RI shows the site is not currently impacting the
groundwater near the landfill. To insure the quality of the
groundwater, a qroundw~ter monitoring plan will be developed
during the design. As part of this plan, the Agency will set
trigger levels for contaminants of conoern (contaminants
identified in the RI). If the monitoring results show that these
levels are being exceeded, a ground water study will be initiated
to further evaluate the site conditions and identify the
potential remedy if required. The Maximum contaminant Levels
(MCLS) established for drinking water are proposed as the trigger
levels for most of the contaminants of concern. Levels for the
.remaining contaminants .of concern (antimony, lead, vanadium, and'
methylene chloride) are calculated based 'on concentrations found
in backqround wells, using a formula developed for monitoring at
RCRA facilities (statistical Analvsis of Ground Water Monitorina
3
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Data at RCRA Facilities. Interim Final Guidance, April 1989).
more extensive discussion of the method of determining the
trigger levels may be found in Appendix Aof the FS Report.
Comment: Deed restrictions are worthless. Deed restrictions can
be eliminated any time in the future if the present owners, .
heirs, or powers of attorney so elect to do.
A
ResDonse:
.'
Institutional controls (such as deed restrictions) can be used
(and typically are used) in conjunction with engineering controls
as part of a remedial action in order to ensure protection of
human health and the environment. Although it is true that at
this site institutional controls, including deed restrictions to
limit land and groundwater use, cannot by themselves be relied
upon to protect public health, they do impose a legal obligation
upon the owner of the property or future purchasers to abide by
the restrictions. If the Agency negotiates a Consent Decree with
Defendants which own Superfund Site property and deed
restrictions are required by that Consent Decree, the deed
restrictions become legally enforcable. Therefore the Agency
believes that requiring deed restrictions, to prevent future
development of the Site or any consumptive use of the
groundwater, will enhance the protectiveness of the remedy. In
the event that deed restrictions are not implemented, and another
institutional control is necessary to ensure protectiveness, EPA
will consider such measures at that time. .
Comment: Almost every comment from the affected community was
adamant in having the Potentially Responsibility Parties (PRPs)
pay for the clean-up.
ResDonse: U.S. EPA has an enforcement first policy and will.
negotiate with the PRPs at this site to conduct the clean-up.
However, if no good faith offer to conduct and/or finance the
remedy is received from the PRPs, U.S. EPA will consider other
options.
Comments
from the Potentiallv Responsibili~y Parties
INTRODUCTORY STATEMENT:
Comments were received from several PRPs and/or their
contractors. Three provided extensive comments, while the others
provided letters supporting the comments of others. All PRP
commentors recommended a no action alternative. To support thi~
recommendation, they offered a number of comments in regard to
the preparation of the risk assessment for the Himco site. These
comments challenged the Agency's approach, exposure assumptions
"
..
4
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~
and methods by which the risk assessment process was implemented.
The Agency believes that the risk assessment process was
conducted in accordance with accepted quidance, applying site-
specific factors and utilizing reasonable yet conservative
assumptions where required. In nearly every instance, the
alternative approach or assumption as suggested by the commentors
would not have affected the choice of the proposed remedy.
Because of the voluminous, redundant nature of the comments
received from the three PRPs, they will be addressed in summary
fashion, grouping comments under major headings. Comments will
be numbered sequentially under each heading for ease of
reference. See the Administrative Record for the specific
comments.
Comments on Assessment of Future Use of the site
Comment Fl: One commentor stated that "The state of Indiana and
U.s. EPA uniformly agree that the property should not and will
not be used for the construction of any buildings." The
commentor provided two letters from the Chief of the Facilities
Inspection Section of the Indiana Board of Health to the Elkhart
County Health Department recommending against construction of
residences on the site. (Miles)
ResDonse Fl: The letters provided only advise aqainst
construction of buildings on the site; they do not prohibit
construction on the landfill. In addition, the letters are
focussed on construction on the landfill itself. They do not
address the parts of the Site beyond the bounds of the landfilled
area.
Comment F2: The same commentor also said installing .groundwater
wells .at.the landfill is prohibited by Indiana law. (Miles)
ReSDonse F2: The commentor is referring to Indiana
Administrative Code, 310 IAC section 16-3-2, which says that a
"well shall be located as follows: ...(2) as far as practicable
from any: ...(8) known contamination source. This does not
outright forbid a well being installed on the .ite. The ri.k
assessment process looked at future risk scenarios in terms of
what is reasonably possible for the entire site if no remediation
took place, not what could potentially be prevented through
institutional controls (a remedial measure) on the landfill.
Comment F3: One commentor stated that U.s. EPA quidance suggests
that risk assessment. .hould include a qualitative .tatement of
the likelihood of the future land use occurring and quoted the
Risk AS8essment as saying that .'this scenario' (re.idential or
commercial development) "may not be technically and/o~ . .
. financially reasonable". (Geraghty' Miller)
5
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ReSDonse F3: The Risk Assessment does state that,
"...composition of the natural soils in combination with the
shallow water table and fill material would make construction on
the site difficult and potentially costly." However, it qoes on
to say that construction "alonq the perimeter of the site (not on
the landfill) would be more feasible."
CommentF4: Commentors stated that u.s. EPA incorrectly assumed
that the HIHCO property will be used in the future for
residential, industrial, and agricultural purposes and that
construction will occur on the landfill. One commentor indicated
that the NCP requires u.s. EPA to evaluate the likelihood that
future populations will be exposed to contaminants on the subject
property. (Hiles, Geraqhty & Hiller, Himco Waste-Away Service/
Hittelhauser) .
."
ResDonse F4: The Aqency does not agree that there is "no doubt"
that the site will never be used for any residential,
aqricultural or industrial purposes. In fact, inquiries as to
the feasibility of site development for residential and liqht
industry were explored as recently as 1984. '
The role of the baseline risk assessment is to develop scenarios
for relevant, possible land uses in the absence of institutional
controls. Residential, aqricultural, and industrial uses are all
possible although their likelihood differs. The possibility of
each of these is based on factors includinq surroundinq land use
in the area, historical uses of the land (portions of the site
were once agricultural) and developmental feasibility.
Additionally, the baseline risk assessment provides qualitative
information on the likelihood of a future land use actually
occurring. For instance, at this site the risk assessment
clearly stated that there is low probability of a future
residential or commercial land use (at least on the landfilled
area), there is some likelihood of the site returning to
aqricultural uses, and there is some probability that the site
could be developed for recreation. This type ot information
provides the EPA risk manaqer the basis for selecting the extent
,of remediation which will be required.
It is important to distinquish between the "site" and the
"landfill." There is'nothinq at this time that renders it
unlikely that homes may be built on the site 80uth of the
landfill. Homes have been built along County Road 10 south of
the landfill. The contaminated area between County Road 10 and
the landfill is obviously a place where people miqht be likely to
build homes if it were not for the risk posed by soil
contamination and contaminated leachate. Institutional controls
such as zoninq prohibitions, fencing, p08tinq of siqns and othe~
'restrictions simply cannot ensure that the site will never be
used in the future. 'Since there is some likelihood of 80me kind
of future use (people have even been known to place homes on
.. -
6
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landfills), it is appropriate for the risk assessment to evaluate
such exposures and for risk management decisions to take this
information into account in making remedial decisions.
Comments on the around water Dathwav
comment Gl: One commentor quoted the RI/FS that revealed "very
little or no ground water contamination outside the boundary of
the landfill" and that "ground water has not been impacted to a
level of health and environmental concern by the site
contaminants," and concurred with these conclusions. (Geraghty &
Miller)
ResDonse Gl: The U.S. EPA acknowledges the commentor's
concurrence with our conclusions.
Comment G2: The groundwater pathway should be eliminated because
the ground water is not currently used, is not potable and is not
likely to be used in the future. (Miles, Geraghty & Miller, Himco
Waste-Away Service/Mittelhauser) .
ReSDonse G2: Although there are no current users adjacent to the
landfill, there are drinking water wells in the nearby
surrounding area. As recently as a year ago a resident just
southwest of the landfill drilled a drinking water well. It is
not certain that the groundwater will never be used as a drinking
water source; therefore, it is appropriate to evaluate such a
possibility. The aquifer in question is a Class II aquifer, and
so, the Agency is obligated to protect it. The contaminants of
concern (listed in Table 4 of the ROD) identified in the
groundwater below the landfill clearly present an unacceptable
risk and cannot be allowed to migrate. The construction of a cap
over the landfill will help prevent the generation of additional
leachate and the contamination from migrating in the future, and
the ground water monitoring will detect if this remedy does not
provide the containment/control expected. If the contamination.
had been shoWn to have migrated already, the Agency would be
obligated to restore this Class II aquifer.
Other Comments Reaardina the Risk Assessment
Comment Rl: The trespasser scenario is incorrect for the
following reasons: 1) the activity i. illegal, 2) the emission
rate did not account for days of precipitation, and 3) two
different numbers were used for silt content. (Miles)
ReSDonse R1: 1) The legality of a human activity is not
. re~evant in evaluating exposure. 'There~. sufficient evidence
that dirt bike riding occu~s at the site to warrant its'
inclusion. Trails are evident and the activity was observed
7
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during field work at the site. Exposure thus Occurs whether the
rider has gained legal access to the site or not.
2) The emission rate is calculated only during a bike riding
event. It was assumed that bike ridinq would only occur on days
when it'was not raining. (If a person rode in the rain, the
emissions would probably not occur, therefore there would be no
exposure.) For this reason the term in Cowherd's equation
accountinq for days of precipitation would be equal to one. Thus
the emission rate calculated in the risk assessment would not
chanqe with the inclusion of this parameter.
~
3) Both the dirt bike and tilling models require a silt content
term in their respective equations. These activities are assumed
to occur in different areas of the site. During the remedial'
investigation, samples from these respective areas were analyzed
for qrain size. An estimate of silt content is also made with
these analyses. These ,results were used in the ,modelinq. It is
not surprising, it is even expected, that silt content varies
from location to location across different areas of the site.
CQmment R2: The box model was inappropriately applied for the
followinq reasons: 1) use of one-half the heiqht of the box, 2)
the calculation of X, 3) the average wind speed measurement, 4)
the lack of a dispersion model for the downwind receptor, 5) the
unrealistic assumption that an adult will dirt bike ride on the
landfill for 30 years. (Miles)
Response R2: 1). One-half the height of the box was used in the
calculations for the following reasons. First it was assumed
that the upwind edqe of the box was located at the upwind edqe of
the source area and the downwind edqe of the box occurred at the
downwind edqe of the source area. A plume of suspended particles
was assumed to rise from the upwind edge of the box and reach the
mixinq height calculated at the downwind edge of the source. '
Since a hypothetical resident or dirt bike rider could live or
ride anywhere within this box, the averaqe heiqht of the box
(8/2) was used to calculate exposure to that individual. This
approach may tend to overestimate exposure for a resident (or
rider) living (or ridinq) near the downwind edqe of the box and
underestimate exposure for a resident (or rider) at the upwind
edge ot the box. '
2) It is true that the assumption that the box is square is not
stated in the risk assessment. This assumption was indeed made;
the calculation of X is correct.
3) The wind speed from the nearest available weather station was
used in place of on-site meteorological data, which were not
available. It is li~ely,that the measurement was made at a
heiqht of 10 meters. It is also assumed that obstructions near
the surface would slow the windspeed, resulting in a lower annual
r -
, -
8
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averaqe wind speed at the heiqht used in the box model. Use of a
.hiqher windspeed than actually occurs at the heiqht that was
evaluated is likely to have underestimated exposure. The
maqnitude of this underestimate cannot be reliably estimated.
4) It is aqreed that the box model is not reliable for estimatinq
exposures at siqnificant distances downwind from a source.
However, at this site, the nearest off-site current residents are
located just east of the edqe of the landfill.. Therefore, they
were assumed to be located effectively at the downwind edqe of
the box. While some uncertainty was introduced by assuminq that
the nearest current resident was located at the downwind edqe of
the box, it was judqed acceptable for risk assessment purposes.
It should be remembered that this is not a sophisticated model--
its intent is for screeninq purpos~s. The model predicted very:
low emissions which represent risks well within an acceptable
ranqe. ~isks contributed by this pathway were not siqnificant
relative to overall site risks and did not form the basis for the
proposed remedy. Further refinement of the air pathway is not
warranted.
5) The Aqency disaqrees that the adult dirt bike rider is
unrealistic. Adulthood does not necessary brinqthe cessation of
this type of activity. Aqain, the pathways involvinq air .
exposures were not siqnificant in their contribution to total
site risk. Therefore the use of exposure factors that the
commentor feels are overly conservative did not influence the
selection of a remedy.
One commentor offered a number of comments about other exposure
analyses, as follows. (Miles)
Comment R3a: The soil concentrations are biased hi9h and
misapplied since samplinq was not random.
ResDonse R3a: The samplin9 desiqn utilized at this site was a
stratified systematic desiqn. The desiqn was a consistent
pattern apportioned across the site areas. Two exposure areas
were defined and assumed: on the landfill and south of the
landfill. This method, while not random, is nevertheless
unbiased. It is appropriate for use in defininq representative
concentration values over the two exposure areas. If the
samplinq were biased, avera9inq samples over an exposure area
would not have been appropriate.
Comment R3b: Episodic air emissions should not be added to
steady-state ~onq-term atmospheric exposures in the UBK model for
lead. .
ResDonse R3b: It is true that the UBK model does not routinely
handle episodic air emissions. The UBK model does allow for both
9
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an ambient air default or other inputs based on site measurements
or predictions from air modelinq. At this site, the additional
emissions predicted from the tillinq or dirt bike ridinq
activities are several orders of maqnitude lower than the ambient
default value in the model. Therefore, addition of the episodic
emissions had no effect on the model outcome. .
Comment R3c: Assumed parameters for exposure factors are
arbitrary. For example, the skin surface area for children
(commentor did not identify any other examples.)
Res90nse R3c: It is true that the use of an assumed skin surface
area of 10,000 cmA2 is sliqhtly hiqher than the value now
recommended by EPA in its Dermal Guidance document. That value
is 8,000 cmA2, which is the 95th percentile of the averaqe. of aqe
classes 1-6. Use of this number would sliqhtly lower the risk
estimates for children via dermal ~xposures to qroundwater. (For
example, the excess cancer risk estimates for the hypothetical
future child resident on the landfill would drop from 7E-01 to
6E-01.) This is not a siqnificant difference.
The revision of the Exposure Factors Handbook, referred to by the
commentor, is still a preliminary draft (July 1991). However,
the values suqqested in that draft correspond to the values
suqqested in the released Dermal Guidance (as described above).
Comment R3d: Two HIF terms in the evaluation of the aqricultural
worker were reversed.
ResDonse R3d: The Aqency aqrees these terms were inadvertently
reversed when risk calculations were performed. This error has
been corrected and the risk results are summarized below:
Route.
Cancer Risk
(oriqinal)
Cancer Risk
(revised)
HI HI
(oriqinal) (revised)
---------------------------------------------------------------
Inqestion of 3E-03 3E-03 1E+0 1. 1E+01
Groundwater
Inqestion of 4E-06 4E-06 2E-02 2E-02
50il .
Inhalation- 5E-05 2E-06 4E+00 2E-01
Particulates
Inhalation- 2E-09 3E-08 4E-06 7E-05
Volatiles
Total 3E-03 3E-03 1E+01 1E+01
(all pathways)
As seen above, total risks to the population would not chanqe
10
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although the individual pathway risks are different. Again, the
inhalation pathway contributes little to overall risk and those
results did not form the basis for the selection of a remedy.
Comment R3e: The exposure assessment for showering arbitrarily
assumes inhalation intake is twice oral intake.
ResDonse R3e: This assumption is not arbitrary but based on
several experimental studies as cited in the risk assessment. It
is agreed that this is a simplifying assumption applied as if all
the volatiles present in groundwater volatilize equally. It was,
however, applied only to those compounds which volatilize easily.
The relative bioavailability, if relevant, was accounted for in
the toxicity value applied for each route. It should be noted
that the inhalation of volatiles from household uses of .
groundwater contributes relatively little to the overall risk
from groundwater pathways.
Comment R3f: The estimate of PM10 in the air for an agricultural
worker (35 mg/mA3) is excessive and unreasonable.
ResDonse R3f: Tilling dry fields is a dusty activity. Whether
it exceeds an OSHA limit is .irrelevant. It is acknowledged, .
however, that the estimate derived in the risk assessment is
conservative. The model used is a screening level procedure.
Despite the use of this high-end estimate, there is no cause for
concern from the site via this pathway and these results did not
form the basis for the selected remedy.
Comment R3a: Endpoint specific estimates of noncarcinogenic
hazard indices should have been developed.
ResDonse RJa: It is appropriate to segregate the compounds by
effect and/or mechanism it the HI is greater than one as a result
of summina. That is, if the HI becomes greater than one because
individual HQ values are each less than one. At this site,
individual HQs for a number of chemical IA£B exceed one,
therefore this segregation step is not required.
Comment R4: Two commentors questioned the use of one-half the
detection limit to estimate ground water concentrations. One
indicated that the use of one-half the detection limit of
compounds found in soil and leachate samples to estimate
concentrations in groundwater violates EPA's quidance, which they
believe is invalid between different media. (Miles, Himco Waste-
Away Services/Mittelhauserl
ResDonse R4: The Agency believes the use of one-half the
detection .limit is appropriate. The reference the commentor
cites (RAGS pq. 5-10) '1s silent on the concept of "in a medium".
It is true that the quidance does instruct the risk assessor to
11
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qenerallv eliminate chemicals that have not been detected in any
samples from a particular medium. It furthermore states that if
information indicates that the chemicals are likely to be present
in a medium, based on fate' and transport mechanisms, they should
not be eliminated. The guidance uses an example of soil
contaminants that can leach to groundwater where those compounds
have not yet been detected 'at some given laboratory
quantification level. This concept has been similarly applied
for the leachate. The term leachate, as used throughout the
remedial investigation, may be somewhat misleading. In reality,
this leachate is groundwater in contact with or contaminated by
the waste material in the landfill. This leachate is highly
contaminated as evidenced by the water samples taken from test
pits when the water table was encountered. Although these
chemicals have not been detected in the existing wells south of
the landfill, there is the potential that these chemicals could
migrate from the areas where they have been detected. In this
case, the use of one-half the detection limit is an appropriate
surrogate. The RAGS guidance clearly indicates that nondetects
should not simply be eliminated from the risk assessment, or a
value of zero be applied. '
The detection limits presented in the tables in Appendix 2 of the
risk assessment (range of nondetects) were reported by the
analytlcal laboratories as contract-required detection limits,
with adjustments for dilution and percent moisture made where
applicable. These levels generally correspond to the limit of
quantification. It is agreed that sample quantification limits
are more relevant for evaluating nondetects. They were, however,
not available. Instrument detection limits, however, are not'
suitable for use in a risk assessment since factors such as
sample preparation, dilution, etc. are not considered.
It is true that this method of estimating exposure point
concentrations indicated high risk,levels from chemicals that may
really be absent. On the other hand, they may be present at
levels just below what the laboratory can measure, resulting in
even higher risk than that calculated. This information was'
utilized in'the risk ~anagement decision not to require treatment
of the groundwater, but to further monitor the situation.
Comment R5: Total site risks were calculated and background
risks were not excluded from risk estimates. (Miles)
ReSDonse R5: The Agency's RAGS guidance clearly instructs the
risk assessor to calculate total site risk and suggests
calculating background risk separately fro~ site-related risk
(RAGS, Pg. 5-18) if the risk assessor believes that background.
chemicals (or non-site-related chemicals) are significantly
. contributing to unacceptable risk. Thi~ is the methodology
employed 'at this site. ~he results as presented in the risk
assessment indicate that there is a portion of the total site
- -
12
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risk attributable to background (either naturally occurring or.
upgradient sources). This information was considered in the risk.
management decision not to require treatment of the groundwater,
but to further monitor the situation.
It is true that the Agency's Data Useability Guidance instructs
the risk assessor that chemicals falling within naturally-
occurring levels AND below a concentration of concern may be
eliminated from the risk assessment. Since a number of naturally
occurring chemicals were present at levels approaching a level of
concern, no naturally occurring chemicals were eliminated from
the risk assessment.
Comment R6: u.s. EPA improperly included leachate data to
calculate ground water contamination. (Miles)
ResDonse R6: As stated previously, in Response R4, above, the
leachate is indeed .contaminated groundwater. In calculating
exposure point concentrations for groundwater in this area, a
combination of leachate samples and groundwater wells in the
proximate area were used to estimate the concentrations of these
chemicals that would be available to a future hypothetical
receptor. Based on the site subsurface data, it is possible that
a pumping well installed in the landfill area will capture some
leachate. However, because of the highly heterogeneous nature of
the landfill, it is not possible to make a realistic prediction
of how much and for how long leachate will be captured by the
pumpinq well, therefore leachate data were included in the risk
assessment for exposure to the groundwater under the future land-
use scenario.
Comment R7: Chemicals detected infrequently should have been
eliminated from the risk assessment and chemicals attributable to
blank contamination should also be eliminated. (Miles)
Response R7: The commentor infers that application of a
frequency of detect rule is required, when in fact it is an
option. Guidance indicates "If conducting a risk assessment on a
large numb~r of chemicals is feasible...then the procedures in
this section (including frequency of detection) should not be
used" (RAGS, Pg. 5-20).
. As stated on Page 2-7 of the Risk Assessment, an analysis of
blank contamination was conducted according to EPA guidance.
This guidance applies a "5X or lOX" rule for chemicals detected
both in blanks and in the actual samples. Data points were thus
modified as appropriate.
Comment R8: The toxicity assessment is incorrect because: 1)
outdated toxicity values. were used, 2) the TEF approach for PABs
was not used and 3) the oral absorption for beryllium was not
addressed. (Miles)
13
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ResDonse RB: 1) The toxicity assessment was performed in April,
.1992 using toxicity values current at that time. The Agency does
not require the risk assessment be updated every time a toxicity
value changes. The magnitude of the effect on the risk estimates
for benzo(a)pyrene would not be significant considering that risk
estimates are rounded to one significant figure. Neither does
the Agency recommend the development of "site-specific" toxicity
values.
o'
2) There is no final Agency position as yet on the toxicity
equivalency approach for PAHs. The approach remains under
review. Therefore, the risk characterization for PAHs in this
site risk assessment meets the current quidance, which is to
apply the slope factor for benzo(a)pyrene to all carcinogenic
PAHs. '
3) The Agency recognizes that there iS'uncertainty involved in
both estimating oral absorption factors for many chemicals,
including beryllium, and in the current methodology for
extrapolating toxicity values from an oral exposure route to a
dermal exposure route.
The only dermal route quantified at this site was dermal
exposures to groundwater while showering and incidental exposure
to waders at the on-site ponds. While risks for the surface,
water exposures were well within an acceptable risk range, dermal
exposures to groundwater, via beryllium were higher. They were
nevertheless not significant when compared to other pathways
involving exposures to groundwater. The considerable uncertainty
in evaluating dermal pathways contributed to the risk management
decision not to require treatment of the groundwater at this
time, but to further monitor groundwater at the site.
Comment R9: Datavalldation procedures are not sUfficiently
documented. (Miles)
ResDonse R9: As mentioned on page 2-6 of the risk assessment,
data collected were reviewed and validated by U.S.EPA according
to standard validation procedures for the Contract Laboratory
Program. This validation was conducted by Region V's Central
Regional Laboratory. Results of the validator'. comments were
incorporated into the database used for risk assessment
calculations. As a result of this effort, a number of R-
qualified data points were eliminated from use in the risk
calculations. (R-qualified data points are data points which the
data validator indicated are unusable because the presence of the
compound in question cannot be verified.)
, -
Comment a10: Major sources of
the risk assessment, including
and the uncertainty 'due to the
hexavalent. (Miles)
uncertainty were not considered in .
unacceptable spike recovery data
assumption of all chromium as
'- -
14
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ResDonse RiO: The Aqency believes that uncertainties have been
sufficiently documented. In the two examples cited by the
commentor the followinq responses are offered:
1) The occurrence of an out of control spike does not necessarily
warrant an unusable condition. Rather, affected data are
qenerally "J" or "UJ" qualified, and as such are still usable for
risk assessment purposes. .
2) It is acknowledqed that the assumption that all chromium
occurs in the hexavalent form is conservative. This would be
particularly relevant when quantifyinq an air pathway, since
hexavalent chromium is considered carcinoqenic; trivalent
chromium is not. However, estimates of risk from these pathways
were not siqnificant when compared to total site risk and did not
form the basis for the proposed remedy.
comments reaardina site Characterization
Comment Sl: All three commentors indicated that U.s. EPA failed
to consider the effectiveness of the existinq calcium sulfate
cover and layerinq. (Miles, Himco Waste-Away
Services/Mittelhauser, Geraqhty , Miller)
ReSDonse 51: The analytical results of the leachate samples
from the landfill indicate that the landfill contains wastes
contaminated with orqanic and inorqanic compounds. The proposed
remedy for this site includes a composite cap to alleviate
potential exposures to the landfill wastes. The commentors claim
that the calcium sulfate waste dumped at the landfill is
sufficient to eliminate present and future exposures to the
landfill wastes and is protective of human health and the.
environment. U. 5. EPA does not aqree with this evaluation for
the foll~winq reasons:
*
The calcium sulfate layer has not been placed on'the
landfill under an enqineerinq-controlled system as required
by U.S. EPA and IDEM for a clay cover on a landfill.
. The thickness of .the calcium sulfate layer is not
sufficient in many areas of the landfill. The thickness
was l..s than 2 feet in 62.5 percent of test pits excavated
on th. landfill.
*
*
The chemical interaction between water and calcium'sulfate
make it less favorable as a cap material relative to most
clayey materials.
Comment S2: One commentor provided a sworn affidavit.of
. Mr. Jerry D. Perrin, former employee at the HIMCO Dump, taken on
15
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November 30, 1992, in which he states, "I placed all the wastes
between successive layers of soil and a material known as calcium
sulfate." (Miles)
ReSDonse S2: Field observations of test pits do not confirm this
statement. Twenty-four test pits were excavated in the landfill
as a part df the RI for this site. Of these, eight test pit.
were observed to have alternating layers of calcium sulfate and
waste (TD-3, TL-1, TP-9, TP-10, TP-11, TP-12, TP-13, and TP-20),
indicating daily coverage of waste with a calcium sulfate layer.
Alternating layers of waste and calcium sulfate were not observed
in the majority of the test pits excavated in the landfill (16 of
24, or 66.7 percent). One possible explanation for the
discrepancy between Mr. Perrin's statement and the actual field
observations is the lag time between the landfilling operation
and Mr. Perrin's employment with the Himco Dump. Mr. Perrin
worked at Himco between 1970 and 1976; however, the site was in
operation between 1960 and 1976. Based on the above information
and the unbiased distribution of the test pits in the landfill
area, it is apparent that daily coverage was not practiced in
more than 50 percent of the landfilling operation.
Comment S3: In Mr. Perrin's affidavit, he states, "When the
landfil~ was closed in 1976, Himco placed a final cover of
c~lcium sulfate averaging at least two feet thick..." (Miles)
..
ReSDonse S3: This statement is not supported by the field data.
The calcium sulfate cover thickness was found to be less than
2.0 feet in 15 of the 24 test pits excavated (62.5 percent). In
addition, the calcium sulfate layer was less than or equal to
0.5 feet in five of the test pits on the landfill. Based on the
above information and the unbiased distribution of the test pits
in the landfill area, it can be concluded that a layer of calcium
sulfate 2 feet or more thick has not been placed in more than
half. of. the landfill area. .
Comment S4: Assumptions used by U.S. .EPA for compact.d
vegetative layers are inconsistent with accepted practice.
.(Geraghty , Miller)
ResDonse S4: It is w~ll documented on landfill closures and on
mine reclamation projects that placement of veqetativ8 8Upport
and top.oil layers by modern equipment will create greater
compaction than most natural soil conditions. Agricultural
tillage practices are typically designed around minimizing
compaction; .011 placement practices usually are not.
Regardless of the placement method, the use of compacted
vegetative support lay.rs in modeling reduce. infiltration. Th~
'barrier layers can be modeled alone, and. the results will still
reflect that the composite .system results in the least amount of
infiltration. .
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16
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We agree that excessive compaction can impact
but this modeling task alone does not address
specifications or the selection of vegetation
be successful. .
vegetative success,
technical
species which can
Comment S5: Assumptions used by u.s. EPA for runoff curve
numbers are inconsistent with accepted practice. (Geraghty'
Miller)
ResDonse S5: High curve numbers (CN) were used to emphasize the
impact of the barrier layer. The lower the infiltration rate,
the more efficient the barrier must be to prevent deeper
infiltration. We agree that the CN could have been lower to
reflect expected vegetative and soil conditions if construction
is successful. To show that the composite liner still is the
most effective, we re-ran the modeling with default values and
with a CN of 95. In each case the vegetation layer was
uncompacted. The following table shows the infiltration under
various cap designs.
ADnual Infil~ra~ion
Under Different cap De.iqn.
CR=95
Poor Gr...
CR=..
Poor Gr...
CB:"
~
Gra..
No Action (Zone A)
Single clay Cap
composite Cap
4.6 in.
2.9 in.
0.001 in.
4.6 in.
7.2 in.
0.001 in.
4.5 in.
7.0in.
0.001 in.
The estimated higher infiltration for a single cap relative to
the No Action Alternative is due to the errors associated with
the numerical simulation of the' infiltration. Por example, the
No Action Alternative depicts the top 1-inch of calcium sulfate
as the veget~tive layer with the remainder acting as a barrier
soil. This creates a condition of increased runoff and lower
soil water evapotranspiration. Accurate field data equating
calcium sulfate to barrier soil properties would allow more
accurate determinations to be made. None the .le.s, the table
shows that the composite cap provides the best protection against
infiltration. Therefore, the composite cap option is the best
performer.
Comment S6: Assumptions used by U.S. EPA for vegetative cover
. conditions are inconsistent with accepted p~actice. (Geraghty'
Miller)
. ReSDonse S6: The use of a full vegetative coverage in the
modeling reduces the ~nfiltration by modeling evapotranspiration.
The poor cover is used to determine the effectiveness of the.
17
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barrier rather than relying on successful veg.tation to minimize
infiltration. As is shown in the above table, the use of poor or
good vegetative cover has minimal modeling impact on the
intiltration rate. The ~omposite cover is still. the best
available option.
Comment S7: Assumptions used by U.S. EPA tor soil barrier
texture number are inconsistent with accepted practice. (Geraghty
& Miller) .
"
Response S7: The use of the barrier soil with a HELP (model)
texture number ot 16 and 17 was performed. Texture 16 retlects a
permeability of lxlO~ em/see and texture 17 reflects lxl04
em/sec. The modeling results with a CN-66, poor grass, and no
compaction ot vegetative layers are. summarized in the following
table:
sinqle clay
Soil Barrier
Texture 16
Texture 17
Infiltration
1.25 in.
0.13 in.
Published papers have documented that a field permeability of
lxlO~ em/see is difticult to achieve. It is our opinion that
lxl04 em/see would not be achievable on a landfill cover due to
an unstable foundation (waste) and long-term vegetation and
animal impacts.
However, modeling still shows that a single clay cap is less
effective than a composite cover. With the absence of a base
liner, leachate extraction system, and the close proximity to
groundwater, U.S. EPA believes the cover must provide the best
restriction to intiltration. It a cost-benetit analysis is
required to predict how much inti"ltration is allowable, the HELP
modeling will not give that answer. Source control has been
proven as the most ettective control ot potential groundwater
contamination; theretore, since source removal is not part of the
selected remedy, the most ettective cap should be employed.
Comment S8: One comment or provided a lengthy, admittedly
"obviously idealized" characterization of the hydroqeology ot the
landtill, concluding that the landtill area had been "8ilted in"
prior to landfilling, which, in effect, created a natural liner
under the landfill. The commentor state. that SEC Donahue failed
to identify this natural liner. (Himco Waste-Away
services/Mittelhauser)
Re.Donse S8: U.S. E~A f.els this portrayal of the landfill
hydroqeology is not accurate for the following reasons:
~ -
18
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.
The high permeability glacial outwash deposits in the"
region, and man-made structural barriers (e.g., roads,
trenches, etc.) prevent excessive surface runoffs in the
site vicinity. These features do not support the
hypothesis of standing water in the landfill area and the
resulting formation of a natural silt/clay liner during
its geologic history prior to the landfill operation at
the Himco site.
.
Aerial photographs .taken in Auqust 1965, when landfilling
occurred in an approximately 6.5-acre area southeast of
the site, show no standing water in the landfill area.
All borings preformed in and around the site (e.g., B-1,
B-3, B-8, B-11, E-1, B-7, M-1, M-2) (see Fiqures 3-9. and.
3-11 of the RI report) without exception show no silt and
clay layers at t~e approximate base elevation of the
landfill. All of the borings indicate sand and gravel
deposits classified as SP or SW in the Unified Soil
Classification System, extending from surface to the
bottom elevation of the borings. Silt and clay layers
occasionally were encountered in the borings; however,
none were encountered at the level corresponding to the
. base of the landfill (an approximate elevation of 755 feet
MSL).
.
Comment S9: One commentor provided a discussion regarding the
PAR compounds determined to be present in the south portion of
the landfill, conjecturing that they may be attributable to peat
or to asphalt, since they believe no coal tar wastes were
disposed of in the landfill. (Himco Waste-Away Services/
Mittelhauser)
ReSDonse S9: The source of the PAR compounds found in the south
portion of the Site was not determined. Presumably, they were
disposed during landfill operations. In any case, they are
hazardous substances that have come to be located on a superfund
site and have been determined to present a significant risk and
therefore, must be remediated.
Comments on the No Action Alternative
comment N1: The remedial action objectives are fully satisfied
by No Action. (Miles, Geraghty' Miller, Himco Waste-Away
services/Mittelhauser)
Resnonse .N1: . The results of the RI indicate that the waste mass
is contaminated by VOC'., SVOCs and inorganic.. The results of.
the baseline risk asse.~ment indicate unacceptable carcinogenic
and/or noncarcinogenic risks for human exposure. to the landfill
contents, primarily ~ue to exposure to highly contaminated
19
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qroundwater, i.e., leachate. The FS identified remedial action
objectives (RAOs) for the Himco site (paqe 2-2 of the FS). None
of these objectives are met by No Action.
.
Direct contact with the landfill wastes is not
prevented. The suqqestion that the inclusion of calcium
sulfate as cover material has resulted in the construction
of an enqineered waste encapsulation unit is not correct.
Field 10q8 do not confirm uniform qradinq of a calcium
sulfate cap that would meet today's standard for landfill
closure activities.
.
Groundwater usaqe in the site vicinity is not controlled by
No Action, as a new well was just installed south of the
landfill while the RIfFS was undertaken. .
.
The calcium sulfate cover does not effectively control
leachate qeneration in the landfill. No Action would allow
the continued percolation of rainfall across the landfill. .
No Action would allow the continuinq miqration of
contaminants from the waste mass to the qroundwater beneath
the site and would allow the miqration of VOCs and noxious
odors from the site due to the lack of vapor controls from
the landfill.
.
.
The lonq-term cap inteqrity will not be maintained because
surface runoff control and a qas collection system will not
be implemented under the No Action alternative.
Comment N2: u.s. EPA failed to develop the No Action
alternative. One commentor requested that u. S. EPA ree~amine
the ARARs compliance of the No Action Alternative. (Miles,
Geraqhty. , Miller, Himco Waste-Away Services/Mittelhauaer)
ResDon.e N2: The No Action alternative has been. adequately
evaluated, alonq with three other alternatives, in the FS
reports. Each alternative was evaluated aqainst the nine
criteria established by the NCP for detailed analysis of
alternatives. Table 4~5 of the FS report presents a summary of
this evaluation. The No Action alternative does not achieve the
threshold criterion of overall protection of public health and
the environaent. The No Action alternative would not be
protective of human health and the environment for the followinq
reasons: .
.
. . .
The calcium sui fate cover is not in compliance with today's
standards for caps on landfills and would allow the
continued percolation of .rainfall across the landfill.
Althouqh the calcium sulfate does retard the percolation of
rainfall across the landfill, the calcium sulfate waa not
. -
20
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'v
*
placed in the landfill uniformly, so the potential for
channeling and leakage of infiltration into the landfill is
high.
The calcium sulfate cap is prone to dissolution and erosion
as a result of surface water percolation into the landfill.
This effect was observed in some test pits performed in the
landfill. The test pits showed calcium sulfate thickness
of less than 6 inches.
*
The chemical interaction between water and calcium sulfate
make it less favorable as a cap material relative to most
clayey materials.
The No Action alternative would allow the migration of VOCs
and noxious odors from the site due to the lack of vapor
controls in the landfill. EPA received frequent complaints
from the residents in the vicinity of the landfill
regarding odors from the landfill. One such complaint was
voiced in the public meeting for the proposed plan.
*
*
The No Action alternative would allow direct contact with
the landfill waste material which is contaminated with both
organic and inorganic compounds. The test pits performed
during the RI showed calcium sulfate cover thickness of
equal or less than 6 inches in five test pits and l..s than
2 feet in 62.5 percent of the test pits.
The No Action alternative would allow other potential risks
as described in the FS report.
*
The No Action Alternative does not have to be carried through the
comparative analysis if it is shown that it does not pass the
threshold criteria. Clearly, the No Action Alternative does not
pass .th~se criteria for the HIMCO Dump Site.
. .
Comments reaardina Other Remedial Alternatives
Comment 01: U.S. EPA failed to ensure that appropriate remedial
alternative. are devel.aped. (Miles) .
Re8Dons. 01: The FS report systematically evaluates an array of
remedial technologies, formulates a range of alternatives, and
screens the developed alternatives in detail according to the
quidelines presented in both Conducting RIfFS for CERCLA
Municipal Landfill sites and Guidance for Conducting RIfFS under
CERCLA. Each of the alternatives, including No Action, were
fully developed and evaluated in the FS report.
- -
The only difference between. the Himco FS and a typical FS is that
screening a universe of technologies, as suggested under EPA'.
21
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quidance for the RI/FS, was not included in the Himco FS. This
approach was undertaken because landfills have similar
characteristics and EPA has, based on its experience and
according to guidance, established a number of expectations as to
the type. of remedial alternatives to be evaluated for municipal
landfills.
Comment 02: One commentor stated that the need for an active
landfill gas collection and treatment system has not been
demonstrated. (Geraghty & Miller)
ResDonse 02: U.S. EPA acknowledges that the gas generation rate
in the Himco site is not like typical municipal landfills as a
result of the high volume of calcium sulfate waste disposed of at
this site. However, considerable gas generation has been
documented for this site. For example, the air monitoring
performed as a part of the safety requirements during
installation of test pits showed high levels of organic vapor and
presence of hydrogen sulfide (~S). Additionally, numerous
complaints regarding odor have been expressed by residents in the
vicinity of the landfill. One such complaint was voiced in the
Proposed Plan public meeting. In addition to gas generation due
to the decomposition of non-calcium sulfate wastes, it is also.
likely that the reduction of sulfates to hydrogen sulfide under
anaerobic conditions within the landfill is a source of the odors
noted at this site. Based on this information, the FS included
gas remediation as a part of the selected remedy for the Himco
site.
In calculating the gas generation rate, only one third of the
material in the landfill was used as possible methane producing
material. As presented in the Technical Memorandum AS, the total
gas generation rate ranged from 6.68 x 106 SCF/yr to 66.8 x 106
SCF/yr or equivalent to 0.010 SCF/lb/yr to 0.1 SCF/lb/yr. If the
factor of 1/3 gas-producing was~e volume (0.02 to 0.3 SCF/lb/yr)
would be considered, the range encompasses the figure 0.15
SCF/lb/yr indicated by the commentor as a "typical 9as generator.
rate" in the. landfill.
It should be noted that the result of the gas generation rate did
not have a siqnificant effect on the selected remedy or cost
estimate for the .elected remedy.
Comment 03: One commentor stated that they believe the cost.
given in the PS Report for the two capping systems appear to be
underestimated. (Geraghty' Miller) .
. .
ResDonse 03: The quote. used in estimating capping costa are.
documented in Appendix 84 - Index of Telephone Log. of the Final
. Feasibility Study Report for the Himco D~p Superfund Site. The
quote taken from a .local v~ndor only includes the soil material
.
22
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and haul costs, as stated in the telephone log.. Similar quotes"
were received from other local vendors for soil material and
haul. The costs for placement and compaction of this material
are included in the cost estimate for capping at this site (see
Appendix 81 Cost Assumption tables). The costs for placement and
compaction were compiled from the Means Heavy Construction Cost
Data, 1992 (Means). Because the quotes that were received were
low relative to estimates from Means, estimates from Means for
material and haul were used as the Upper Limit value in the cost
Sensitivity Analysis in the FS.
Comment 04: One commentor stated that the leachate collection
system described in Alternative 3 is ill-conceived and not well-
thought out. (Himco Waste-Away ServicesfMittelhauser)
ReSDonse 04: U. S. EPA does not agree with the commentor's
assertion that the Agency does not have a basic understanding of
the Site hydrogeology. " The commentor provided little more than
conjecture, without technical information to back it up, that the
leachate collection system is not well designed.
Because there is no aquitard under the HIMCO Dump to isolate the
waste mass from the aquifer and the waste mass is in contact with
ground water at least part of the year, it was judged that the
leachate collection system would need to consist of vertical
wells distributed throughout the whole landfill area to capture
the leachate.
Comment 05: One comment or stated that the Selected Remedy is
inconsistent with the NCP because it is not cost-effective. "
(Miles)
ResDonse 05: Cost effectiveness is determined by evaluating
overall effectiveness, which is baaed on long-term effectiveness
and permanence, reduction of toxicity, mobility, or volume
through treatment, and short-term effectiveness. U.S. EPA
believes that the Selected Remedy is cost-effective because it
provides the best balance of these three criteria and the cost is
proportional to the overall effectiveness. The Agency does not
agree with "the commentor'a assertion that No Action is
appropriate, or that institutional controls provide the same
remedial value as the proposed cap. The Agency's rationale has
been explained in previous responses.
SummarY of Other Comments Received
Comment Sl: The Conclusions of the RIfFS and U.S. EPA's Proposed
Remedy are Arbitrary and Capricious and Contrary to Law. (Miles)
ReSDonse Sl: The Agency does not agree with the commentor that
it acted arbitrarily and capriciously in the performance of the
23
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RI/FS or in its selection of a remedy for the HIMCO Dump Site.
Comment S2: TWo commentors indicated that u.S. EPA failed to
conduct"a proper Preliminary Assessment in violation of the NCP.
One commentor concluded that because significant contamination
was not found in the ground water during the RI, the sample
results used for the HRS score were in error. (Miles, Himco
Waste-Away Service/Mittelhauser)
~
ResDonse S2: U.S. EPA does not agree with these assertions. No
evidence is given to substantiate the assertion that past
sampling events were in error or that a proper PA was not
conducted. The PA/SI sample collection was performed in
accordance with NEIC Manual for Groundwater/Subsurface
Investiaations at Hazardous Waste Sites. Sample preservation and
analysis were performed according to CLP procedures. The HRS
scoring process includes rigorous quality assurance procedures,
which the HIMCO Dump Site passed.
Comment S3: TWo commentors indicated that sites which pose no
significant risk to public health or the environment should be
deleted from the NPL. They assert that the HIMCO Dump Site is
" such a site. (Miles, Himco Waste-Away Services/Mittelhauser)
ResDonse S3: U.S. EPA agrees that sites that pose no risk to .
public health or the environment should be deleted from the NPL.
However, the'Agency does not believe that the HIMCO Dump Site
does not pose a risk. The responses to Comments Nl and N2 detail
the Agency's position on this issue.
Comment S4: One commentor stated that "Miles and Himco are
prepared to fund the erection of an appropriate fence to further
prevent site access and to fund reasonable groundwater
monitoring. While these controls are unnecessary given the
complete lack of a risk at Himco, Miles and Himco are prepared to
fund these efforts to address the public concern at the site."
(Miles) .
Re.Donse S4: 0.5. EPA thanks Miles and Himco for their offer.
However, as' stated in the Record of Decision and the above
re.pon.e. to comments, the Agency clearly doe. not believe that
the action. proposed by Miles and Himco are an acceptable remedy
for the BXMCO Dump Site. .
-
~ -
- -
24
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DATA
documents are available for review at:
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Chicago, IL
1.
Title
Quality Control Documentation/Analytical Data
Pages
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GUIDANCE DOCUMENTS INDEX
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T~ase documents have ~O~ beer copied. They may be reviewed at
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:~'9/24/92
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N. Niedergang
E:PA-D. Heaton
uPDATE
February 12. 1991
Ullrich, D..
Waste Mgt.
Division
TIT~E/DESCRIPTrON
Memo Qn residential
well data
Sampling action
Memo on ~AT's site
inspection
TAT site inspection
Removal Action
Memorandum
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11
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