United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R10-91/028
August 1991
<&EPA Superfund
Record of Decision:
Bunker Hill Mining and
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50272-101
REPORT DOCUMENTATION 11. REPORTNO.
PAGE EPA/ROD/R10-91/028
I ~
3. Recipient. AcceMion No.
4. 11118 end Subtl1l8
~UPERFUND RECORD OF DECISION
~nker Hill Mining and Metallurgical
rirst Remedial Action
7. AuU'lor(a)
5. Report Dat.
08/30/91
Complex, ID
6.
a. Pwfonnlng Organization RepL No.
II. Pwfonnlng Org"nizatlon Ham8 end Add,....
10. ProjectlT MIllWork Unit No.
..
11. ContI'8ct{C) or Grant(G) No.
"
(C)
(G)
1~ Spor.ortng Organization Nama end Addre..
U.S. Environmental Protection
401 M Street, S.W.
washington, D.C. 20460
13. Type 01 Report & Period Covered
Agency
800/000
14.
15. Supplemantary No..
HI. Abetract (Urnlt: 200 worda)
The Bunker Hill Mining and Metallurgical Complex site is a 21 square-mile area centered
around an inactive industrial mining and smelting site, and includes the cities of
Kellogg, Smelterville, Wardner, Pinehurst, and Page, in Shoshone County, Idaho. The
inactive industrial complex includes the Bunker Hill mine and mill, a lead smelter, a
Lnc smelter and a phosphoric acid fertilizer plant, all totalling several hundred
~res. Furthermore, the site includes the South Fork of the Coeur d'Alene River, an
alluvial floodplain bordered by mountains, numerous valleys and gulches, and vegetated
residential areas. In 1886, the first mill for processing lead and silver ore was
constructed at the site. Operations were expanded in later years with the addition of
a lead smelter; a blast furnace; and electrolytic zinc, sulfuric acid, phosphoric acid,
and fertilizer plants. Onsite operational and disposal practices have caused the
deposition of hazardous substances (e.g., metals) throughout the valley via airborne
particulate deposition, alluvial deposition of tailings dumped in the river, and
migration from onsite sources. Initially, most of the solid and liquid residue from
the complex was discharged into the river. When the river flooded, these materials
were deposited onto the valley floor, and have leached into onsite soil and ground
(See Attached Page)
17. Doc_t Analy". L Dnc:riptora
Record of Decision - Bunker Hill Mining and Metallurgical Complex, ID
First Remedial Action
Contaminated Medium: soil
.Key Contaminants: metals (arsenic, lead)
b. IdentifteralOpan-Endad Tenne
c. CooA 11 F\eIdIGroup
1I8I/iiabiMty Statement
111. Secwity Cia.. (Thl. Report)
None
20. Secwity Cia.. (Thl. Page)
Nnnp
21. No. 01 Page.
144
2~ Price
(See ANSI-Z38.18)
See InalnK:/iona on RtI-
272 (4.77)
(Formerty NTI~3S)
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EPA/ROD/R10-91/028
Bunker Hill Mining and Metallurgical Complex, 10
First Remedial Action
~ract (Continued)
water. Although some of the industrial wastes have been removed and disposed of
offsite, thousands of tons of sludge, tailings, flue dust, and other wastes still remain
onsite. Contamination at the site is a result of tailings depo.sition in the floodplain,
. and airborne deposition from smelter and mill complex emissions. A fire in 1973
severely reduced air pollution control capacity at the lead smelter. A 1974 public
health study and concurrent epidemiologic and environmental investigations concluded
~ that atmospheric emissions of particulate lead from the active smelter were the primary
sources of elevated blood lead levels in local children. In 1977, two tall stacks were
added to disperse contaminants from the complex. The complex ceased smelter operations
in 1981, but continued limited mining and milling operations from 1988 to early 1991.
In 1989, EPA began a removal program to excavate lead-contaminated soil from affected
residential properties. Federal and State agencies have designated a 21-square-mile
study area, which has been divided into populated areas and non-populated areas for
remediation. This Record of Decision (ROD) addresses contaminated residential soil
within the populated areas of the site, and includes four incorporated communities and
three unincorporated residential areas as Operable Unit 1 (OU1). The nonpopulated areas
of the site as well as all other contaminated media in the populated areas (e.g., house
dust, and commercial properties) will be addressed in a future ROD. The primary
contaminants of concern affecting residential area soil are metals including arsenic and
lead.
The selected remedial action for this site includes soil sampling; excavating
taminated soil and sod exceeding 1,000 mg/kg lead on approximately 1,800 residential
erties, and replacing it with clean soil and sod; disposing of the contaminated soil
and sod at an onsite repository; capping the repository; placing a visual marker if lead
levels in soil exceed 1,000 mg/kg below the depth of excavation; revegetating the area;
conducting long-term environmental monitoring; and implementing institutional controls
including deed and land use restrictions. The estimated present worth cost for this
remedial action is $40,600,000, which includes an annual O&M cost of $460,000 for 30
years.
PERFORMANCE STANDARDS OR GOALS: Residential soil with lead concentrations greater than
1,000 mg/kg will be excavated and replaced with clean material resulting in mean soil
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'...-
RECORD OF DECISION
Bunker HilllVlining and Metallurgical Complex
Residential Soils Operable Unit
Shoshone County, Idaho
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CONTENTS
Page
Declaration for the Record of Decision
D-l
Record of Decision Summary
1-1
1
Site Description
1-1
2
Site History and Enforcement Activities
2.1 Site History
2.2 Initial Investigations
2.3 Remedial InvestigatioDIFeasibility Study (RIJFS)
2.~ History of CERCLA Enforcement
2.5 Removal Actions
2-1
2-1
2-2
2-3
2-4
2-5
3
HighlightS of Community Participation
3-1
4
Scope and Role of Operable Unit
4-1
5
Site Characteristics
5.1 Physical Setting
5.2 Nature and Extent of Contamination
5.3 Contaminant Migration
5-1
5-1
5-1
5-12
6
Summary of Site Risks
6.1 Human Health Risks
6.1.1 Exposure Assessment
6.1.2 Toxicity Assessment
6.1.3 Risk Characterization
6.1.4 Human Health Risk Summary
6.1.5 The 1,000 ppm Threshold Oeanup Level
Environmental Risks
6-1
6-1
6-1
6-3
6-4
6-8
6-9
6-10
6.2
7
Detailed Description of Alternatives
7.1 Alternative I-No Action
7.2 Common ComponentS of Alternatives 3- Variable Cut/Removel
Flll/Disposal; 5-Sod RemovaIlSod Replacement/Disposal;
6--Deep RemovaIJFlll/Disposal; and 8- Variable Cut/Removel
Fill/rrea tID isposal
7.2.1 Institutional Controls
7.2.2 Revegetation
7.2.3 Dust Suppression During Remediation
7.2.4 Excavation/BackfilVCover
7.2.5 Extent of Remediation
7.2.6 Disposal
7.2. 7 Environmental Monitoring
Alternative 3-- Variable Cut!RemovelFill/Disposal
Alternative 5-Sod RemovallSod Replacement/Disposal
Alternative 6--Deep RemovaIJFilllDisposal
Alternative 8- Variable Cut!RemovelFillfTreatlDisposal
7-1
7-1
7-2
7-2
7-2
7-2
7-3
7-3
7-3
7-4
7-4
7-5
7-6
7-7
7.3
7.4
7.5
7.6
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CONTL'ITS (Continued)
Pa
8 Comparative Analysis of Alternatives 8-1
8.1 Protection of Human Health and Environment 8-1
8.2 Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs) 8-1
8.3 Long-term Effectiveness 8-1
8A Reduction of Toxicity, Mobility, Volume, and Persistence through
Treatment 8-2 '(
8.5 Short-term Effectiveness 8-2
8.6 Implementability, Reliability, and Constructibility 8-3
8.7 Cost 8-3
8.3 State Acceptance ~
3.9 Community Acceptance ~
9 The Selected Remedy 9-1
9.1 Introduction 9-1
9.2 Residential Soils Summary 9-1
9.3 Changes to Proposed Plan 9-5
9.4 Cost 9-6
9.5 Performance Requirements 9-6
1"0 Statutory Determinations 10-1
10.1 Protection ot Human Health and the Environment 10-1
10.2 Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs) 1~
10.3 Cost-Effectiveness 1O-1~
lOA Utilization of Permanent Solutions and Alternative
Treatment Technologies to the Maximum Extent PractiClble 10-15
10.5 Preference for Treatment as a Principal Element for the Residential
Soil Operable Unit
Responsiveness Summary for the Residential Soil Operable Unit
Glossary and List oC Acronyms and Abbreviations
Attachment-Administrative Record Index
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i,..,
TABLES
Page
2-1 Major Features and Investigation Emphasis 2-4
2-2 Potentially Responsible Panies Identified for the Bunker Hill Superfund Site 2-5
5-1 Summary of Residential Soil Metal Contamination Levels 5-2
5-2 Residential Propenies With Lead Concentrations Above 1,000 ppm Lead 5-5
5-3 Summary of Road Shoulders and Railroad Right-of-Way Sample Survey 5-7
5-4 1986 "Fast-Track" Removal Effons and Lead Recontamination Surveys 5-8
5-5 Fugitive Dust Source Areas 5-10
5-6 1987 and 1989 Air Monitoring TSP Data (~g/m3) 5-14
5-7 Summary of Air Filter Metals Data (~g/m3)--1987 and 1989 Event Monitoring 5-15
5-8 Geometric Mean and Extreme House Dust Metal Concentrations
1974, 1975. 1983, and 1988 Lead Health Survey (ppm) 5-16
5-9 Individual Filters with TSP > 150 ~g/m3 November 1987 to November 1988 5-18
6-1 Contaminants Evaluated, Exposure Routes and Sources, and Exposure
Scenarios Addressed in the Risk Assessment 6-3
6-2 Summary of Most Sensitive Adverse Health Effects of Site Contaminants of Concern 6-4
6-3 Available CPFs for Site Contaminants of Concern 6-4
6-4 Noncarcinogenic Effects and Associated RIDs for Site Contaminants of
Concern 6-5
6-5 Summary of Baseline and Incremental Carcinogenic Risk Estimates 6-6
6-6 Summary of Exposure Routes, Scenarios, and Potentially High-Risk Activities
That Could Result in Unacceptable Chronic Risk to Noncarcinogenic Disease 6-7
8-1 Summary of Estimated Costs 8-4
9-1 Risk Range for a Threshold Level of 1,000 ppm 9-3
"
~.
l
f.
k.
,
t...
."
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TABLES (Continued)
Pa
9-2 Summary of Estimated CDsts for Sel~ted Remedy 9-1
10-1 Federal Chemical-Specific ARA.R.s 10-3
10-2 Federal LoC3tion-Spedfic ARA.R.s 10-5
10-3 Federal Action-Specific ARA.R.s 10-1 16
1~ Slate of Idaho Chemic:ll-Specific ARA.R.s 10-11
10-5 State of Idaho Loc:ltion-Specific ARA.R.s 10-12
10-6 State of Idaho Action-Specific ARA.R.s 10-13
FIG URES
1-1 Bunker Hill RIIFS Study Area 1-2
1-2 Populated and Non-populated Areas of the Site 1-3
1.3 Populated Areas RrJFS--Ciry of Kellogg 1
1-4 Populated Areas RrJFS-Ciry of Pinehurst 1-~
1-5 Populated Areas RifFS-Ciry of Smelter.riUe 1-6
1-6 Populated Areas RIJFS--Ciry of Wardner 1-1
1-1 Populated Areas RIJFS-Ciry of Page 1-8
5-1 Potential Source Identific:ltion Map for Windblown Dusts 5-11
5-2 Air Monitoring Loc:1tions 5-13
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DECLARATION
FOR THE
RECORD OF DECISION
SITE NAME
.
Bunker Hill Mining and Metallurgical Complex Site
Populated Areas
Residential Soils Operable Unit
LOCATION
Cities o( Kellogg, Smelterville, Wardner. Pinehurst. and other residential areas within the site
Shoshone County. Idaho
STATEMENT OF BASIS AND PURPOSE
This decision document presentS the remedial action selected by the U.s. Environmental Protection
Agency and the Idaho Department of Health and Welfare for the Populated Areas Residential Soils
Operable Unit at the Bunker Hill Mining and Metallurgical Complex Site in nonhem Idaho. The
remedy was chosen in aax>rdance with CERCLA. as amended by SARA. and. to the extent practicable.,
the National Contingency Plan. This decision is based on the Residential Soils Administrative Record
file for this site, and the index is attached.
. .
ASSESSl\1ENT OF THE SITE
Actual or threatened releases of hazardous substances from this site, if not addressed by implementing
the response action selected in this Rea>rd of Decision (ROD), may present an imminent and substan-
tial endangerment to public: health. welfare, or the environmenL
. -
DESCRIPTION OF THE REMEDY
"..
L
~..,
The Residential Soils Operable Unit is the first unit to be addressed at Bunker HilL Exposure to lead
1a resideudal soBs bas beeu ldentifted as the primary beaJtb risk to ch.iJdreu and pregnant women
wftbID the Populated Alas of the site. Residential soils are not a .prindpal threat. at this site (as
defined by U.s. EP A-see Glossary). although they represent a significant lead exposure pathway to the
loc:a1 population.
l
i.
Exposure to interior bouse dust and consumption of locally grown garden produce have also been identi-
fied as significant contaminant c::xposure pathways to people. ContaminantS of concern for garden pro-
duce include lead and cadmium.
0-1
-------
Remediation of residential soils will break the direct contact exposure pathway betWeen people and
those soils. In addition. implementation of the selected remedy will remove a source of metal-<:ontami-
nated dust to home interiors (residential soils are a source of house dust), and provide safe garden
areas.
The residential soils reme;dy consists of the following:
.
Removal of contaminated surficial soil
.
Placement of a visual marker if lead in soil concenU'3tions exceed 1.000 ppm below the
depth of acavation
~
.
>
Replacement with clean soil (these soils will function as a barrier betWeen residents and
underly1ng contaminated material)
.
Revegetation of yards
.
Disposal of contaminated materials
.
Dust suppression during remediation
.
Institutional controls for barrier management
.
Long-term environmental monitoring for evaluation of remedial effectiveness
A Remedia.l Action Objective is to decrease the concenU'3tion of lead such that 9S percent or more of
the children in the area have blood lead levels below 10 }J.g/dl This remedial action is expected to
achieve community mean soil lead concenU'3tions of approximately 200 to 300 ppm by removal of soils
exceeding the threshold level of 1.000 ppm lead. Approximately 1.800 residential propenies will be
remediated based on t.h.is criterion. U.S. EPA and IDHW have determined that residential yards cleaned
up in 1989, 1990. and 1991 were done so in a manner consistent with this Record of Decision. These
properties will be included in the wtitutionaJ Controls Program.
To meet the health based Remedia.l Action Objectives. contaminated fugitive dust must be controlled
and lead concentrations in home interior dust must be reduced. It is expected .that there will be at least
one other Record of Decision that will address fugitive dust. interior dust, and all other remaining issues
for the site.
SfATUTORY DETEAAllNATIONS
The selected remedy is protective of human health and the environment. complies with federal and state
requiremencs that are legally appliC3ble or relevant and appropriate to the remedial action. and is cost-
effective. This remedy utilizes permanent solutions and alternative treatment technologies to the maxi-
mum extent practicable. However. because treatment of the metal-<:ontaminated residential soils was
found to be not practicable, t.h.is remedy does not satisfy the statutory preference for treatment as a prin-
cipal element of the remedy. Treatment was determined to be impracticable based upon effectiveness
and cost (actors.
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Because this remedy will result in hazardous substances remaining onsite above health-based levels, a
review will be conducted within 5 years after commencement of remedial aCtion to ensure that the
remedy continues to provide adequate proteetion of human health and the environmenL
.
a~-
~P. Donovan
DirectOr
Idaho Department of Health and Welfare
a~d~/t'r
Date
. .
~a~
Dana A. Rasmussen
Regional Admini~tratOr
U.s. EP A Region 10
~ 3:;, /t(Q(
Date
to.
-
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RECORD OF DECISION SUMMARY
Site Name:
Bunker Hill Mining and Metallurgical Complex Site
Populated Areas
Residential Soils Operable Unit
Location:
Cities of Kellogg, Smelterville, Wardner, Pinehurst; and other residential areas
within site boundaries
Shoshone County, Idaho
"
1 SITE DESCRIPTION
The Bunker Hill Mining and Metallurgical Complex Superfund Site is located in Shoshone County, in
northern Idaho, at 47"5' north latitude and 116°10' west longitude (Figure 1-1). The site lies in the
Silver Valley of the South Fork of the Coeur d'Alene River (SFCDR). The Silver Valley is a steep
mountain valley that trends from east to wesL Interstate Highway 90 crosses through the valley, approx-
imately parallel to the SFCDR. The site includes the town of Pinehurst on the west and the town of
Kellogg on the east (Figure 1-2) and is centered on the Bunker Hill industrial complex. The site has
been impacted by over 100 years of mining and 65 years of smelting activity. The complex occupies
several hundred acres in the center of the site betWeen the towns of Kellogg and Smelterville.
The agencies [U.S. Environmental Protection Agency (U.S. EPA) and Idaho Depanment of Health and
Welfare (IDHW)] bave designated a 21-square-mile study area for purposes of conducting tbe Remedial
Investigation/Feasibility Study (RIIFS), which has been divided into Populated Areas and Non-populated
Areas. This Record of Decision (ROD) addresses contaminated residential soils within the Populated
Areas of the site. Soils throughout the site have been contaminated by heavy metals, to varying degrees,
through a combination of airborne particulate deposition, alluvial deposition of tailings dumped into the
river by mining activity, and contaminant migration from onsite sources. Onsite sources include the
industrial complex, tailings and other waste piles, barren hillsides, and fugitive dust source areas located
throughout the site.
f'
The Populated Areas of the site consist of four incorporated communities and three unincorporated
residential areas. Except for the eastern portion of Kellogg, all of these communities lie south of U.S.
Interstate 90 (1-90), betWeen the highway and steep hillsides to the soutb. Ponions of the residential
areas lie within the floodplain of the South Fork of the Coeur d' Alene River.
, .
1..9
This ROD addresses currently established residential areas. The city of Kellogg (see Figure 1-3) is
6 miles east of the western edge of the site and approximately 1 mile east of the smelter complex. The
population is estimated to be 2,600 with about 1,100 residences. The next largest population center is
the city of Plneburst (see Figure 1-4) with 700 residences and about 1,700 people. It is located on the
western edge of the site, about 1 mile south of 1-90. Smelterville (see Figure 1-5), with a population of
about 450 and 270 residences, is approximately 3 miles east of the western edge of the site and lies along
a minor anerial road linking it to Pinehurst and Kellogg. The town is about 1 mile west of the smelter
complex. The city of Wardner (see Figure 1-6) is contiguous with the southeast ponion of Kellogg and
is approximately 6 miles east of the western boundary of the site. The population of Wardner is cur-
rently about 300 people with 130 residences. The unincorporated community of Page (see Figure 1-1) is
about 1 mile east of the western edge of the site. Most of the land is owned by American Smelting and
Refining Company (ASARCO), while the homes are owned by the residents. Population of Page is
estimated to be about 100 to 150 people, and the area includes 65 residences. Two unincorporated resi-
dential areas located along the eastern site boundary are Elizabeth Park and Ross Ranch with popula-
tions estimated to be 120 and 50 people, respectively.
.....
~ I.
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-
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@
SOUTH FORK
COEUR D'AI..ENE !IIVeN
SHOSHONE
COUNTY
coeUR
D'ALENE .
. BOISE
Figure 1- 1
BUNKER HILL
RIIFS STUDY AREA
BUNKER HILL POPULATED AREAS RifFS
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iii
,.
I
r-' ~
/
,
#,/
17'
J
I
~
I'
,
I
ELIZABETH
r~~->-
-----
RON)S
RNERS" STREAMS
""E ftOJHDNl(
SITE PLAN I
" .5
HILES
.
JI
LEGEND
I I I I
RAILROAD
C 1TY BO.JNDARY
POPULATED AREAS
PROJECT BO.JNDARY
-----
----
Agur. 1-2
POPULATED AND NON-POPULATED
-------
"d lial
o non-resl en
"00 residential
~ OCCUp.
ITIIll vacanl residential
500 roo
I
Figure 1-3 '-""AS RIIFS
POPULA TED SO IL RECORD
-------
o non-residcnlial
~ occupied residenltal
unn vacanl residenlial
500 0 500 FElT
I I I I I
Figure 1-4
POPULATED AREAS RIIFS
RESIDENTIAL SOIL RECORD
-------
Cily of Smellerville
Shoshone County, Idaho
o lIon-re£ldenlJal
m occupied re£ldenhal
rnrn vacant re:iidential
fiX)
I
o
I
fiX) m.T
I
Figure 1-5
POPULATED ~. 5 AI IFS
.- AESIQENTIAL SOIL AECOAD
-------
City of Wardner
Shoshone County, Idaho
o non-residenlial
~ occupied residenlial
nnn VdCanl residenlial
~
I
o
I
~ ffiT
I
Figure 1-6
POPULATED AREAS RIIFS
RESIDENTIAL SOIL RECORD
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~-@
-
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..
--
-
~
-
---
~ occupied re:iideotli1l
rnrn Vclcaot resideotii1l
ita
f'
Flgur. 1-7
POPULATED --lEAS RIJ1=S
RESIDENTIAL SOIL RECORD,
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2 SITE mSTORY AND ENFORCEMENT ACTMTIES
2.1 SITE HISTORY
..
The Bunker Hill Superfund Site is pan of the Coeur d'Alene Mining District located in nonhern Idaho
and western Montana. Gold was first discovered in the district in 1883. The first mill for processing
lead and silver ores at the Bunker Hill site was constructed in 1886 and had a capacity of 100 tons of
raw ore per day. Other mills subsequently were built at the site and the milling capacity ultimately
reached 2.500 tons per day.
The Kellogg-based Bunker Hill and Sullivan Mining Company, incorporated in 1887, was the original
owner and operator of the Bunker Hill complex. In 1956, the name was changed to the Bunker Hill
Company and in 1968, Gulf Resources and Chemical Company of Houston. Texas, purchased the
company and operated the smelter until it was closed in late 1981. The complex was purchased in 1982
by the Bunker Limited Pannership (BLP), headquanered in Kellogg, Idaho. BLP subsequently sold
portions of the complex propenies to several relat~ or affiliated entities including:
.
Syringa Minerals Corporation
Crescent Mine
Bunker Hill Mining Company (U.S.), Ine.
Minerals Corporation of Idaho
.
.
.
The Bunker Mining Company resumed mining and milling operations in 1988 and subsequently ceased
those operations in 1991. .
. .
The Bunker Hill and Sullivan Mining Company was originally involved only in mining and milling lead
and silver ores from local mines. From 1886 until 1917, the lead and silver concentrates produced at the
site were shipped to offsite smelters for processing. Construction of the lead smelter began in 1916 and
the first blast furnace went online in 1917. Over the years, the smelter was expanded and modified. At
the time of its closure in 1981, the lead smelter had a capacity of over 300 tons of metallic lead per day.
An electrolytic zinc plant was put into production at the site in 1928. Two sulfuric acid plants were
added to the zinc facilities in 1954 and 1966, and one sulfuric acid plant was added to the lead complex
in 1970. When it was closed in 1981, the zinc plant's capacity was approximately 28S tons per day of
cast zine. A phosphoric acid plant was constructed at the site in 1960 and a fenilizer plant was built in
1965. The primary products from these plants were phosphoric acid and pellet-type fenilizers of
varying mixtures of nitrogen and phosphorus. The industrial complex ceased operation in 1981 except
for limited mining and milling operations mentioned above.
Control of atmospheric emissions, solid waste disposal, and wastewater treatment at the Bunker Hill
complex evolved with changing technologies and regulations. Initially, most liquid and solid residue
from the complex was discharged into the South Fork of the Coeur d'Alene River and its tn"butaries.
The river periodically flooded and deposited waste material laden with lead, zinc. and other heavy metals
onto the valley floor. Operation and disposal practices caused deposition of hazardous substances
throughout the valley. Leaching of these deposits through the soil has contn"buted to heavy metal con-
tamination of the river and groundwater.
A 1973 fire in the baghouse at the lead smelter main stack severely reduced air pollution control
capacity. Total paniculate emissions of about 15 to 160 tons per month, containing SO to 70 percent
lead, were reponed from the time of the fire through November 1974. This compares to emissions of
about 10 to 20 tons per month prior to the fire. The immediate effects of increased total lead emissions
and high total lead in air content were observed in a 1974 public health study where a significant
-------
number of children had elevated blood lead levels. Lead smelter stack emissions following the 1973
baghouse fire are a significant souro: of current site contamination.
In 1977. tall stacks (>600 feet) were added at botb tbe zinc and lead smelters to more effectivety dis-
perse contaminants from tbe complex. These devices decreased sulfur o:rides concentrations in tbe late
19705. The smelter and otber Bunker Hill Company activities ceased operation in December 1981. and
p
-------
Following smelter closure in late 1981. airborne lead contamination decreased by a factor of 10. from
approximately S ~g/m3 to 0.5 ~g/m3. A 1983 survey of children's blood lead levels demonstrated a sig-
nificant decrease in community exposures to lead contamination; however. the survey also found that
several children. including some born since 1981, continued to exhibit blood lead levels in excess of rec-
ommended public health criteria. Acrompanying epidemiological analyses suggested that contaminated
soils and dusts represented the most accessible sources of environmental lead in the community.
Childhood mean blood lead levels have continued to decrease since 1983. These decreases are likely
related to a nationwide reduction in dietary lead; reduced soil. dust. and air levels in the community;
intake reductions achieved through denying access to sources; and the increase in family and personal
hygiene practiced in the community. The latter is reflected in the implementation of a comprehensive
Community Health Intervention Program in 1984 that encourages improved hygienic (housekeeping)
practices. increased vigilance. parental awareness. and special consultation on individual source control
practices such as lawn care. removals, and restrictions. The Community Health Intervention Program
was initiated specifically to reduce the potential for excess absorptions and minimize total absorption in
the population until initiation of remedial activities. Total blood lead absorption among tbe com-
munity's children has been reduced nearly 50 percent since 1983. The incidence of lead toxicity (blood
lead> 25 ~g/dl) has fallen from 25 percent to less than S percent for children in the highest exposure
areas. Recent blood lead monitoring has shown 37 to S6 percent of area children surveyed exceed the
blood lead level of 10 jLg/dL
2.3 REMEDIAL INVESTIGATIONIFEASmILITY STUDY (RIIFS)
The Bunker Hill site was placed on the National Priorities List (NPL) in September 1983 (48 FR
4(658). RI/FS activities were initiated in late 1984 following completion of the 1983 Lead Health Study.
The Bunker Hill Site Characterization Repon (SCR) was the first step in the RI process. The objective
of the SCR was to describe and analyze existing information. The existing information included files
from federaL, state, and local agencies, as well as information obtained from past and present owners and
operators of the industrial complex. The SCR was then used to identify data gaps and develop work
plans for the remedial investigation.
In recognition of the history and complexity of this site. and the continuing need for active health inter-
vention effons. the EP A and IDHW developed an integrated project structure for RI/FS activities. The
site was divided into twO principal ponions-the Populated Areas and the Non-populated Areas. The
Populated Areas include several cities. aU residential and commercial properties located within those
cities, and other residential properties. The Non-populated Areas include the smelter complex. river
floodplain, barren hillsides, groundwater. air pollution. and industrial waste components of the site.
While separate RI/FS effons were initiated for each ponion of the site, U.S. EP A Region 10 retained
oversight and risk assessment responsibilities for both. IDHW conducted the Populated Areas RIfFS.
The Non-populated Areas RI/FS is being conducted by Gulf Resources & Chemical Corporation under
a U.S. EPA Administrative Order on Consent signed by U.S. EPA in May 1987. Table 2-1 lists the
major geographic features and investigation emphases.
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Table %-1
~ajor Features and Investigation Emphasis
~ajor Geographic Features I Investigation Empbasis
PopuJated Areas
. Pinehurst . Contaminated Soils and Dust
. Page . Residential Propenies
. Smelterville . Commercial Propenies
. Kellogg . Roadways/Railways
. Wardner . Fugitive Dust Sources
. Ross Ranch . House Dust
. Elizabeth Parle . Airborne Contamination
Non-populated Areas
. North-Facing Hillsides . Soil and Surface Materials
. South-Facing Hillsides. . Surface Water
. Denuded Hillsides Near Complex . Groundwater
. Bunker Hill Smelter Complex Area . Air/Atmospheric Transpon
. Central Impoundment Area (CIA) . Vegetation
. Smelterville RatS . BuildingslProcess Equipment
. Industrial Corridor . Waste Piles
. River Channel Area . Buried Wastes
. East Page Swamp . Contaminant Migration
. West Page Swamp
. Pine Creek Channel
. Page Pond
..
2.4 mSTORY OF CERCLA ENFORCEMENT
SeveraJ companies have been identified by U.S. EP A as potentially responsible panies (PRPs) for the
Bunker Hill Superfund Site. Table 2-2 listS the PRPs for Bunker Hill and the dates they were notified.
The PRPs represent a combination of past and present property owners. owners and operators of the
various smelting. processing. and production facilities 10c:1ted within the industrial complex. and
upstream mining companies that were responsible for tailings discharges into the South Fork of the
Coeur d' Alene River that have contnbuted to the contamination of the site.
-------
,
Table 2-2
Potentially Responsible Parties Identified for the
Bunker Hill Superfund Site
Name of Company Notification Date
Gulf Resources and Chemical Corporation 10-18-84
Bunker Limited Partnership 10-18-88 and 10-04-89
Minerals Corporation of Idaho 10-04-89
Bunker Hill Mining Company (US.), Ine. 10-04-89
BH Properties, Ine. 10-04-89
Syringa Minerals Corporation 10-04-89
Hecla Mining Company 10-04-89
Stauffer Chemical Company 10-04-89
ASARCO, loe. 02-07-90
Callahan Mining Corporation 02-07-90
Highland Surprise Consolidated-Mining Company 02-07-90
Silver Bowl, loe. 02-07-90
Sunshine Precious Metals, Inc. 02-07-90
Union Pacific Railroad 02-07-90
Coeur d' Alene Mines Corporation 02-07-90
Sunshine Mining Company 06-07-91
.. .
In 1989, U.S. EP A recovered S1.4 million from Gulf Resources & Chemical Corporation in a settlement
regarding Superfund money spent during the removal action in 1986. Agency oversight costS associated
with the Non-populated RIJFS have been received from Gulf Resources & Chemical Corporation for
1987 through 1989. On May 2, 1990, U.S. EP A filed a civil action for penalties against Bunker Limited
Partnership for failure to respond to U.S. EP A's October 1988 request for information. The C3Se is still
pending in U.S. District Court in Boise, Idaho.
2.5 REMOVAL ACTIONS
There have been tWo Superfund-financed removal actions (1986 and 1989 residential soils); one removal
action was financed by the PRPs but performed by the agencies (1990 residential soils); and there have
been three PRP-performed removal actions (1989 Smelter Complex Stabilization, 1990 hillsides revegeta-
tion, and 1991 residential soils, etc.).
In 1986, 16 public properties (parks, playgrounds, and road shoulders) were selected for an immediate
removal action because these properties contained high concentrations of lead and were frequented by
many area children. The action consisted of placing a barrier betWeen children and the underlying
-------
contaminated soil. Six inches of contaminated materials were excavated. and clean soil, sod and/or
gravel were imported for replacement. E'Cc:lvated material was temporarily stored within site boundari
at property owned by the Idaho Transportation Department (lTD).
In 1989, the U.S. EP A and IDHW began a residential soil removal program. The program prioritized
yards that had a lead concentration greater than or equal to 1,000 ppm and housed either a young child
or a pregnant woman. This action consisted of removing 6 to 12 inches of contaminated material from
yards and replacing it in kind with clean material. Contaminated soils were again stored at the lTD
property within site boundaries. In 1989, yard soil replacement was completed at 81 homes and 2 apart-
ment complexes within the Populated Areas of the site.
~
An Administrative Unilateral Order was issued October 2~, 1989 (U.S. EP A Docket Number 1089-10-
21-106), to Bunker Limited Partnership, Minerals Corporation of Idaho, Bunker Hill Mining Company,
(U.S.) Inc., and Gulf Re.sources and Chemical Corporation. The purpose of the order was to implement
actions to stabilize several problem areas within the industrial complex. Actions required by the order
included immediate cessation of salvaging activities onsite, establishment of site access restrictions,
development of a dust control plan, and stabilization and containment of the copper dross flue dust pile.
An Administrative Unilateral Order was issued to all named PRPs on May 15, 1990 (U.S. EPA Docket
No. 1090-05-25-106(a», which required the continuation of the residential soil removal program within
the boundaries of the Superfund site. Settlement of this order resulted in an agreement betWeen U.S.
EP A and eight of the PRPs (Gulf Resources & Chemical Corporation, Hecla Mining Company,
ASARCO, Inc., Stauffer Chemic:ll Company, Callahan Mining Corporation, Coeur d'Alene Mines
Corporation, Sunshine Precious Metals, Inc., and Union Pacific Railroad) for payment of S3,180,OOO to
U.S EPA (U.S. EPA Docket Number 1090-05-35-106) (or performance of the 1990 residential soil
removal action. Yard soil removal and replacement (or an additional 130 yards were performed in
1990. Excavated soils from this removal action were stored at the Page Ponds tailings impoundment.
An Administrative Order on Consent to implement hillside stabilization and revegetation work was
entered into betWeen U.S. EP A and Gulf Resources & Chemical Corporation, and Hecla Mining
Company, on October 1, 1990 (U.S. EPA Docket No. 1090-10-01-106). The objectives of this Order are
to control erosion by reestablishing a native, closed, coniferous forest and understory vegetative cover to
approximately 3,200 acres of barren hillsides and to perform terrace repair and construction of detention
basins, and repair of the rockslide areas in Wardner and Smelterville. Planting of trees is scheduled to
be completed in 1996.
In July of 1991, an Administrative Order on Consent (U.S. EPA Docket No. 1091~17-106(a» was
entered into betWeen U.S. EP A and nine PRPs (Gulf R~urce:s & Chemical Corporation, Hecla Mining
Company, ASARCO, Inc., Stauffer Chemical Company, Callahan Mining Corporation, Coeur d' Alene
Mines Corporation, Sunshine Precious Metals, Inc., Union Pacific Railroad, and Sunshine Mining
Company) that required the PRPs to perform the residential soil removal program. It is expeCted that
approximately 80 more properties will be cleaned up this year. As in 1990, excavated soils were stored
at the Page Ponds tailings impoundment. Under this Order, the parties have also agreed to undenake
sitewide dust control actions; monitor air, groundwater and surface water, enhance the fire fighting capa-
bility at the industrial complex; and provide funding to purchase high-efficiency vacuums (or loan as part
of the Health Intervention Program.
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3 mGHLIGHTS OF COMMUNTIY PARTICIPATION
There has been a long history of community relations activities in the Silver Valley. Since discovery of
elevated blood leads in children in 1974, the IDHW, Panhandle Health District (PHD), and the CDC
have continually worked with area residents to reduce exposures to lead. In 1985 the Shoshone County
Commissioners selected a nine-member Task Force to serve as a liaison between the Bunker Hill
Superfund Project Team (comprised of representatives of U.S. EPA and IDHW and contractors) and the
community. The PHD was contracted by IDHW to perform community relations tasks for the Bunker
Hill Superfund Site. A full-time IDHW staff person has also been stationed onsite from mid-l987 to
presenL Pan of their duties is to assist in community relation activities when needed.
The focus of community contact has been the nine-member Silver Valley Task Force. There have been
3S public task force meetings since May of 1985. These meetings consisted of presentations by the
Bunker Hill Project Team with time for questions and statements from both the Task Force and the
general community. Twenty-three fact sheets have been produced since May 1985 to discuss various
aspects of the RI/FS activities at the site. Site records have also been made available to the public
through four public information repositories. The community was involved in the selection of activities
associated with the residential soil removal actions through a public comment period. This experience,
along with the opportunity to observe the cleanup activity over the last 2 years, has helped familiarize
the community with the remediation of residential soils.
A series of meetings has been held between the PHD and local planning and wning commissions, city
councils, and county commissioners to help develop the "Evaluation of Institutional Controls for the
Bunker Hill Superfund Site.- Institutional control development presentations were also made to local
business and community groups.
The -Risk Assessment Data Evaluation Report.- the "Residential Soils Focused Feasibility Study; the
-Proposed Plan for Qeanup of Residential Soil within the Populated Areas of the Bunker Hill
Superfund Site; and -An Evaluation of Institutional Controls for the Bunker Hill Superfund Site- were
released for public review April 29, 1991. These four documents were made available in the
administrative record file, which is located at the Kellogg City Hall, and the four information
repositories, which are located at the Kellogg City Hall, Kellogg Public Ubrary, Smelterville City Hall,
and Pinehurst!K.ingston Ubrary. The notice of availability of the documents was published in the
-Shoshone News Press- from April 26 through April 30, 1991. The notice outlined the remedial
alternatives evaluated and identified the proposed alternative. A public comment period was established
for April 29 to May 31 and was extended to June 30, 1991, after a request to extend the period was
received. Extension of the public comment period was published in the -Shoshone News Press- May 24
through 26, 1991. A public hearing was held May 23, 1991, to answer questions and take comments.
There were approximately 100 attendees at the meeting. A transcript of questions asked and answers
given at the public hearing is included in the Administrative Record. Responses to written comments
are included in the Responsiveness Summary, which is pan of this Record of Decision.
-------
4 SCOPE AND ROLE OF OPERABLE UNIT
The rationale for separating the Bunker Hill RIIFS into two parts involved both data availability and
confidentiality issues associated with an investigation of private residential properties within the Popu-
lated Areas. With both environmental data and an abundance of human health related data, coUected as
pan of the epidemiological studies, the agencies believed that the Populated Areas RI/FS could best be
completed by government agencies in order to honor confidentiality agreements with individuals and
individual property owners.
The RI-Risk Assessment Data Evaluation Repon (RADER) for the Populated Areas of the Site-has
been completed. The residential soils feasibility study is also complete and is the first unit to be
addressed in a Record of Decision. The other units that are related to the> Populated Areas
investigation that have not been addressed in a decision document include: house dust, commercial
propenies, and road shoulders and rights-of-way. The agencies originaUy expected to address these
issues in a second ROD in 1992; however, the PRPs have approached U.S. EPA and IDHW with a
proposal for a sitewide cleanup that involves aU facets of both the Populated and Non-populated Areas.
The effon to complete the Residential Soils ROD was maintained. because soils are a primary risk to
the residents; however, consolidation of all (see Table 2-1) remaining issues into what is referred to as
the expedited FS is ongoing. The expedited FS is expected to suppon a second ROD for the site that
will address aU contaminated areas and media not covered in this ROD.
The RADER concluded that subchronic lead absorption among young children is the most significant
health risk posed by this site. The greatest risks to young children are associated with ingestjon of
residential yard soils, house dustS, and locally grown produce. Exposure to residential soils is a primary
health risk to area residentS. although residential soils are not a .principal threat. as defined by
U.S. EPA The remedial action described in this ROD is intended to minimize direct contact with and
. ingestion of lead-contaminated residential soils by excavation and replacement of those soils with clean
material While yard soils represent a primary risk to local residents, it is imponant to recognize that
yard soils represent only one component of exposure in these communities. Other sources of
contamination within tbe site must be addressed to prevent additional population exposures and
reoontamination of residential soil because of contaminant migration. No direct action is being taken
for bouse dust lead reduction at this time; bowever, it is expected that bouse dust lead concentrations
will decrease as yard soil lead concentrations decrease and fugitive dust sources are controUed. Pan of
. the ongoing- Health Intervention Program will be to lend higb-efficiency borne vacuum cleaners to
interested residents. Fugitive dust control effons undenaken as pan of the 1991 removal action wiU
further reduce exposures and the transpon of contaminated materials.
Use of a thresbold level of 1,000 ppm lead (i.e., remedial action at any yard with a lead concentration of
1,000 ppm or above) will result in residential community mean soil lead concentrations of approximately
200 to 300 ppm. Current community mean soil lead concentrations are approximately 3,000 ppm. The
goal is to reduce soil lead concentrations such tbat mean blood lead levels are below 10 J.Lg/dl and the
risk for any individual child to have a blood lead level that exceeds 10 J.Lg/dl is minimized.
LocaUy grown produce is a potentiaUy significant exposure route for cadmium and lead to pregnant
women as weU as young children. This action will provide for safe produce gardening areas to ensure
that this exposure pathway is minimized. Currently, the Health Intervention Program reoommends that
produce grown in local gardens not be consumed.
-------
There are approximately 2.700 residential properties onsite. Of those. approximately 50 percent have
been sampled. Of the yards sampled. 65 percent have surface soil concentrations of lead greater than or
equal to l.COO ppm. If the unsampled yards show a similar distribution. this action is expected to
involve remediation of 65 percent (approximately 1.800) of the residential yards within the site.
~
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5 SITE CHARACTERISTICS
5.1 PHYSICAL SETTING
Topography of the Silver Valley consists of an alluvial floodplain bordered on the nonh and south by
steep mountains. The floodplain ranges in width from about 0.1 mile east of Kellogg to approximately
0.9 mile near Smelterville. The elevation of the valley floor ranges from 2.160 feet above mean sea level
at the west end to 2.320 feet at the east end of the project site. The valley floor is nearly level, with
slopes typically less than 1 percenL The mountains rising from the valley range from 500 to 2.500 feet
above the valley floor. The mountainsides typically exhibit slopes of 45 to 90 percent and at some points
exceed 110 percenL Numerous valleys and gulches cut through the mountains and generally trend nonh
to south, intercepting the valley of the South Fork Coeur d'Alene River.
Most residences are located on the valley floor or at the toe of the hillside slopes. Valley floor soils
were formed from alluvially deposited materials and have been strongly influenced by mine tailings
placed in the river as a result of past mining activity. In general, the alluvial valley-fill deposits are com-
prised of silty to clayey sand and gravel Soil parent materials at tbe toe of tbe steep slopes are colluvial
and mixed colluviaUalluvial and are highly erosive. Residential soils have been modified by typical exca-
vation and backfill practices utilized during home construction.
Vegetation in the residential areas includes conifer and deciduous trees, grass lawns varying in quality
with level of maintenance, some vegetable and flower gardens, and native grasses in undeveloped or
steeply sloping areas.
The meteorology of the site is dominated by mountainJvalley drainage winds related to the local
topography. The orientation of the valley effectively channels winds in an east.west direction.
Nocturnal winds average 4.5 mph and tend to be from the easL Late morning and afternoon winds are
from the west and southwest, averaging approximately 8 ~ph. The mean precipitation of the area
ranges from 30.4 inches at Kellogg to 40.5 inches at the nearby city of Wallace, 10 miles east (upstream)
of the site. Data from the National Weather Service collected from 1951 to 1980 show an annual mean
temperature in Kellogg of 47.2"F. A record high of 111°F was reached on August 5, 1961, and a record
low of -36Of on December 30, 1968. On the average, 28 days per year reach a high temperature of 9()OF
or greater, and 143 days reach a low of 32"F or less.
5.2 NATURE AND EXTENT OF CONTAMINATION
The scope of the Populated Areas RI included residential soil, fugitive dust source, house dust, and air
monitoring studies. Contaminants of concern for residential soils are antimony, arsenic, cadmium,
copper, lead, mercury, and zinc. Lead has been identified as the primary contaminant of concern based
on health studies.
Residential yard soil concentrations are presented in Table 5-1. The right-hand column of the table
presents background mean concentrations for comparison. Data from the residential yards show that
metal concentrations hi surficial soils are greatly increased over background. Residential soil contami-
nant concentrations decrease with increasing distance from the mill and smelter complex and result from
a variety of historical industrial activities.
Metal contamination to depths as great as 3 feet have been identified in residential soils. Contamination
sources at this depth are primarily alluvially deposited tailings.
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Table 5-1
StItWr1 Of RfSlOOfTIAL SDIl METAL COIfTNUICATIOII LEVElS
~lTIRVIllE
Page 1 of 3
Concentration, ppm, dry wt. (ppm)
-------
Table 5-1
SIMWrt OF RESIDElTIAl SOIL !£TAl CONTAMlllATIOII L.£VELS
Page 2 of 3
WARDIIER
Concentration, PIXD, dry wt. (PIXII)
---------------------------------------------------------------------------
Arith. Gea1I. Background
Metal Mean Median Mean 95%ile Hin. Max. N Mean
----------------------------------------------------------------------------------------
As 53 47 46 110 14 248 92 < 10
Cd 13 12 11 29 2 33 92 0.8
Cu 79 60 63 167 17 805 92 28
Hg 2 2 2 6 0.2 6 92 0.1
Pb 20~ 1500 1450 5710 151 13200 92. 43
Sb 17 7 7 27 2 663 92 1
Zn 912 820 773 2030 176 4190 92 95
PACE
Concentration, PIXII, drywt. (ppn)
---------------------------------------------------------------------------
Arith. GeaD. Background
Metal Mean Median Mean 95%i le Hin. Max. N Mean
----------------------------------------------------------------------------------------
As 28 25 26 50 11 81 50 < 10
Cd 12 11 10 29 30 50 0.8
Cu 62 51 51 1~ 16 238 50 28
Hg 2 1 4 0.2 7 50 0.1
Pb 1090 810 808 3220 53 3480 50 43
Sb 7 5 5 16 2 32 50 1
-------
Table 5-1
SlJl'.ARy OF RESlDEJlTIAl SOIL ~Al COONUNATIOII lfVELS
Page 3 of 3
PI NDIJRST
Concentration, PIX", drywt. (p~)
---------------------------------------------------------------------------
Arith. Gem. Background
I1et a 1 l1ean I1ed i an l1ean 95%ile Min. /'lax. It l1ean
----------------------------------------------------------------------------------------
As 30 21 23 73 7 123 100 <10
Cd 6 6 5 13 37 100 0.8
Cu 43 oW 39 85 17 167 100 28
Hg 0.5 0.4 0.4 0.1 4 100 0.1
Pb 683 501 %3 1260 63 7990 100 43
Sb 9 7 8 19 5 41 100
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Table 5-2 summarizes the percentage and number of propenies within each community with yard soil
lead concentrations above 1,000 ppm.
Table 5-2
Residential Properties With Lead Concentrations
Above 1,000 ppm Lead
Estimated Total Properties Approximate Number or
Number or > 1,000 ppm Lead Properties
Location Properties (%) > 1,000 ppm Lead
Kellogg 1,320 89 1,175
Wardner 181 69 125
SmeltervilJe 303 88 267
Page 77 37 28
Pinehurst 837 20 167
TOTAL 2,718 65 (Avg.) 1,762
Notes:
1. The estimated total number of propenies to be remediated includes vacant lots within exist-
ing residential areas.
2. The approximate number of residential propenies were calculated using data for samples
collected from approximately 50 percent of the total residences.
3. Information presented in this table was taken from the Risk Assessment Data Evaluation
Repon (RADER) for the Bunker Hill Populated Areas and TerraGraphics. Two hundred
and twenty-one of these residential propenies have already been remediated under the
1989/1990 phased cleanup.
4. The number of propenies presented for Kellogg includes residences in Ross Ranch and
Elizabeth Park.
Soil samples collected from 40 different yards were analyzed for other potential contaminants such as
extractable organic compounds, chlorinated pesticides, PCBs, and mercury. Most organic analytes were
not detected. However, occasional detections were noted for phthalate esters (plasticizer compounds),
some polynuclear aromatic hydrocarbons (i.e., naphthalene, phenanthrene, fluoranthene, pyrene,
benzo(b) fluoranthene, and benzo(a)pyrene as constituents of fossil fuels and their combustion pro-
duCts), and polychlorinated biphenyls (PCBs as components of electrical transformer dielectric fluids).
Chlorinated pesticides were detected in several samples in each town. For those pesticides. observed, the
frequencies of detection range from a low of 14 percent for aldrin, lindane, and heptachlor to a high of
100 percent for DDT isomers and metabolites, chlordane, and heptachlor epoxide. Greatest concentra-
tions and frequencies of detection for pesticides in soils were found in Smelterville, Kellogg, and
Wardner, with significantly lower levels in Page. Presence of organic and pesticide contaminants in resi-
d~ntial soil could not be related to mining and industrial activities associated with the site.
-------
Many residential streetS and roads do not have paved curbs and sidewalks. Metals concentrations from
samples collected from the surface inch of the road shoulders are shown in Table 5-3. Metals concentra-
tions in roadside samples show considerable variation, both geographically and within towns. Samples
from Smelterville ranged from 249 to 60.100 ppm Pb; 3 to 487 ppm Cd: and 19 to 810 ppm As. Samples
from the Sunnyside area of Kellogg (north of 1-90) averaged 1.935 ppm Pb; 19 ppm Cd: and 71 ppm As.
Old Town area (south of 1-90) samples averaged 4.497 ppm Pb; 28.6 ppm Cd: and 81 ppm As. Wardner
and Pinehurst area samples were notably lower, averaging 1.385 ppm Pb; 15 ppm Cd: and 73 ppm As.
Samples of street sweeper dust showed lead contentS from 1.560 to 2.230 ppm and zinc levels exceeding
10, ppm (1 percent).
In 1988 and 1989, efforts were undenaken to assess recontamination at sites cleaned up in the summer
of 1986. Removal actions implemented during 1986 included a 6-inch removal of contaminated soils and
replacement with clean materials and sod in parks and playgrounds. and asphalting or gravel cover of
roadsides and parking lotS. Table 54 summarizes the original (preremediation) lead concentrations.
remedial material (clean fill) lead concentrations. and the tWo rewntamination assessment efforts.
.
The few sod samples collected suggest surface rewntamination rates of 10 to 100 ppmJyr lead. No
recontamination was evident in either the top inch or middle of the soil fill on sodded sites or play
fields. Some rewntamination was evident at the interface of replaced soils and top of the original CUL
Whether this was due to contaminant migration. mixing at the time of placement. or imprecise layering
of the sample is unknown. Rudimentary modeling has indicated that upward migration potential existS
only in isolated areas where there is shallow groundwater.
Graveled areas, panicularty those used as parlring lotS. showed significant recontamination. Because of
the low rates of surface deposition. these increases likety resulted from the continual working of the
original soil layers below the replacement materials or tracking of contaminantS onto the site by vehicles.
Migration and transpon of contaminated solids from the industrial complex and other fugitive dust
sources are a major concern in both the Populated and Non-populated Areas of the site. Windblown
dustS are potentially significant COntnDutors to contaminant concentrations in human receptor media in
the Populated Areas and have been identified as a major source of public complainL Many of the iden-
tified fugitive dust sources are barren soils and impounded wastes and storage piles that can result in
significant amountS of reentrained dusts.
Eighteen major barren areas identified as baving a potentially significant impact on the residential areas
were sampled during remedial investigations in 1986. Table 5-5 identifies the areas sampled. the respec-
tive size of each area. the number of samples collected. summary statistics for lead content in the minus
200-mesh ponion of the sample. and tbe average percentage (by weight) that passed the 200-mesh sieve.
Antimony, arsenic. cadmium. copper, and zinc were also detected in aU samples collected. Locations of
the fugitive dust source areas sampled are provided in Figure 5-1.
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Table 5-3
Summary or Road Shoulders and Railroad Right-or.Way Sample Survey
Sb As Cd Co Pb Hg Zn
(ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm)
Smelterville 9.4 19.4 3 33.9 249 1.3 220
Smelterville 41.7 llS 14.2 186 6,970 3.8 2.590
SmelterviUe 32.7 50.8 26.9 499 2.410 0.06 10,100
Smelterville 40.5 77.7 61.5 274 4,970 0.08 4,770
Smelterville 46.2 267 312 1,950 10,200 2.4 23,600
Smelterville 534 810 487 2.820 60,100 26.2 20,200
Kellogg Sunnyside 8.6 36.2 16.2 106 1,590 0.52 1.560
Kellogg Sunnyside 19.8 103 22.6 297 2,280 0.35 5,360
Kellogg Old Town 34.8 110 31.1 214 7,430 3.8 2.710
Kellogg Old Town 5.9 31.8 28.7 161 1,990 0.94 3,270
Kellogg Old Town 22.6 102 26 305 4,070 0.79 7,210
Wardner 5.2 44.4 12.2 352 1,300 0.16 8.560
Pinehurst 23.2 87.1 11.2 131 1,010 0.24 2,220
Pinehurst 9.4 19.4 9 84.9 72S 0.3 1.520
Pinehurst 13.6 47.1 10.5 290 1,020 0.11 6.740
Pinehurst 18.2 85.9 24.5 475 1,580 0.06 9.980
Pinehurst 5.2 41 9 814 425 0.38 18,700
Pinehurst 12.4 149 12 570 735 0.46 12.300
Pinehurst 36.7 85.1 11.2 596 2.110 0.46 10,600
Pinehurst 21.7 96.2 36.2 700 3,560 0.6 10,900
Page 5.2 23.2 9.2 203 480 0.14 4.390
Page 5.2 24.9 11.8 487 595 0.16 ll,600
Page 5.2 47.7 65.4 842 1.380 1.3 22,500
Elizabeth Park 7 15.1 5.2 99.9 329 0.28 2,200
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- - -u
T..L1e 5-4
I"U ".'8JlI.Tnw:"- lIemow" morta .nd tud Weconi8ollwlUou SUIU)8 (I'..¥e I of 11
n -
IICCUIII..IIII&..oIloll Sun C).
1"'5 IJ.1i t!.PAI
IUIIW
r.......mow" 19U lIellWw" IY.. IY.Y
SUc I.u." A.cllou. Sample Wuulu S"u1Vlc lIe.ul&.
( 'lly 1'111 k 11,370 ppm ..laYIJUund UWI rlUlU lenoLa roUI,lr 17 ,tWO pjllII I'lr t'I")'lIlUuIIJ ('un: I ("411 C 1 ('OIC]
SlIIellervilh:-S4 (In pbYllOu/kJ .Iea) b- relllllvill
CUYC I c..I wll b t'~Yll\)unJ balk (hlill 7'J1. Pl'w t'b U,uk SSllllliU I,om 1'1'111 .HI') 1'1'111
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I~"IIIIIII 1'111 1M 1'1'111 14M 1'1'111 lo'} 1'1'111
'1""1' ur CUI j, S 10 1'1'111 4,'}1O 1'1'111 4,410 l'l'ul
('lIy I'luk Tumoul Turoool dwi huw Nu SIIUll'huil
SlIIellelvllie -S5 AIplLllhc..l ul'h4h 2,M40 ppw t'b
MrKIllh.:y Avenue 24,000 ppm b- relUulIlIl anJ KuaJ chuulJeB Inlllel Nu Sallll'llIllI
SlIIellelville'Sl. Illivel rill
Wal EmJ.Nunb I.'JJO ppw I'b
Wal EnJ.SuUlh ],230 Pl'w I'b
MIJJle-Nunh ],4tW Pl'w I'b
MldJIe.Suulh 2,140 Pl'w I'b
t:.ul l!nJ.Nunh ],1120 ppw I'b
Eul End-Suulh 2,b20 PI'ID I'b
(,"IJ Slrccl 1'111 k 21b ppm b" remulIlIl t'a Gnlvd Nu SlIlIIl'hlill
Kcllugg.KIO repLm: v.-ilb
Pu Inlllel NUl rcnce 1,320 ppw i'b
IQ diilurbc..lIIU 4311 ppm i'b
Itilicisidc i'lIlk I,WS ppm b" reffiOllill Sull Nu SlIlIIplinl
Kclh'ggK'J and replace
Wal Side 35 ppm i'b
Munkey ba.-. 5b ppm i'lr
Slide ]7 PI'III I'b
SlIoingc ]] ppm I'b
SIJIIIIII Avcllue 11,100 ppm Kewuvill 10 Wal End-Nonh 514 1'1)01 I'b Nu Siillll'hll&
Kdlogg K2 boK IInd Wal EnJ.Suulh 4~ ppm I'b
'1lI1Ie:! COIIcr I:"il End-Nonh 317 ppru I'b
-------
Table ~
1986 "Fast-Track" Iltmova) Eltoria and Lead RKOOIamJnaUOO Sune)'ll (Pa&e 1 01 1)
RKoolamlnaUoo Sune)'1l
1985 V.SO UN
IDIIW
Pre-removal 1986 Removal 1988 1989
Site Len" AdJoo8 Sample Kaiulili SMmple Raiulili
Tt:t:lcra Field 2,863 ppm 6" removal and Infield 70 ppm Pb Infield Core I Core 2 Core 3
Kellogg-KI replacemenl or lJaculop 306 ppm Pb
Infkld aru Duplicale 70 ppm Pb 0-1 Inch 22 ppm 77 ppm 43 ppm
Middle Fill 34 ppm 52 ppm 9 ppm
Hollom Fill 120 ppm 188 ppm 373 ppm
Top or CUi 4,130 ppm 5,sOO ppm 8,350 ppm
Memorial Park 2,278 ppm 6" removal Infield 138 ppm Pb Playground Core 1 Core 2 Core 3
Kellogg-K4 Infield Roadb 648 ppm Pb Area
replaced Soulh gravelb 8,800 ppm Pb Uller n ppm )73 ppm -- ppm
Nonb gravcJb 450 ppm Pb 0-1 Inch 2S ppm 26 ppm 15 ppm
Play arcaJ Playground 80 ppm Pb Middle Fill 10 ppm 10 ppm 9 ppm
6" removal 801l0m Fill 324 ppm 2S ppm 26 ppm
and replaced Top or Cut 1,770 ppm 275 ppm 509 ppm
Infield
0-1 Inch 48 ppm 51 ppm 34 ppm
Middle Fill 23 ppm 8 ppm 9 ppm
Hollom 1'111 19 ppm 15 ppm 40 ppm
Top or Cut 921 ppm 2,040 ppm 1,760 ppm
aCh:an soil lead concentraliona 19 to 86 ppm. Oean bart lead concentrations 28 ppm.
-------
! Table s...s I
Fagirm Dust Soaree Areas
Le8d U>DCeDlndoD tugl~)
~p LD. Sl~ ~8D» ~o. ot Afta ~am ~eaa Maimam ~ ot Sample
~ amber Samples (Acres) < :00 ~esb
6 VaCUlt lot west oC 3 9 13,400 19.900 26,600 IS
Minc:raJ Subdivisioa
7 U adcYeJoped area neu 4 6 1.160 1.810 2.500 26
[be Junior Higb ScbooI
11 Area near Sbosbone 3 Z7 30.900 49.100 68.400 ;:g
ApanmenlS
12 Water tre:![ment plant 4 tS .w.000 43.400 ~,700 ....
13 PJrting lot west o( 4 6 212.000 ::32.000 lS2.000 30
Cona::ntntor BwJding
16 Central Impoundment ;)) ISO 117 5.530 lS..300 SI
Area (NOr1b Beacbc:s)
18 Bun.ker ~ Corridor 12 33 10..300 19..300 42.400 31
19 Old bomc:s.ite area 8 9 6.S6O 21,100 47.500 47
;» Old Gypsum Pood 8 29 8..OS0 62.000 as.800 18
21 New Gypsum Pond 12 61 78 2.160 10.900 30
25 Slag pile 12 26 1,370 10,700 18.100 1S
33 Outdoor tbcalcr 8 33 2.9S0 9.190 15.900 18
34 Airpon ~ ::32 11,100 IS.500 28.:00 29
J8 Smdtem1Jc Conidor 16 lZ7 11.600 19.800 32,700 33
39 Rilla' C1annd Flail 12 70 3,970 S..340 6,310 6
44 Page Ponds 12 36 :.560 4.350 6.5S0 68
46 Page Swamp 4 44 J.B.SO 4.710 6,000 57
Smdtervtllc . . 9.690 15,100 25,400 14
.Spc:cifics 0( this sample Site an: OOCltIdentiaJ. as 3greed [0 in [be sampling aa::ess agreement with the property owner.
-------
\
)
LEGEND:
PROJECT BOUNDARY
190
SITE PLAN
o
.6
---~-.-
RIVERS AND STREAMS
RAILROAD
MILES
~
DESCRIPTIONS FOR SOURCE AREA
IDENTIFICATION NUMBERS ARE
PRESENTED IN TABLE 5-5.
j
~t
~
I
~
~
o!?
/
'-
........
'1
, ROSS RANClI
/. ... .- - - - ..... ..J
,. . ;-
; ~ ~~ "
" J ,-
oM NEip ~
/./.,; \
I!- " .
;1 . /; ~.'
"I; J,
'~,j /' g'
~'f ; ¥.'
.91 ...'
i, }'
Figure 5.1
POTENTIAL SOURCE IDENTIFICATION
-------
Highest metal concentrations among fugitive dust sources were found adjacent to the concentrator build-'
ing, with the lead concentration averaging about 230.000 ppm (23 percent), and arsenic and cadmium
levels each at approximately 10.000 ppm (1 percent). Dust content for this sample was high with
30 percent of the solids passing a 200-mesh sieve. The surrounding areas (11 and 12) also have relativ- "
ely high metal cont:!min3nt levels that may be related to emissions from the concentrator area. Barren
. areas near Shoshone ApartmentS (Area 11) and the Water Treatment Plant (Area 12) exhibit approxi-
mately 49.000 ppm (4.9 percent) and 43.000 ppm (4.3 percent) lead in surface dust. respectively. The
arithmetic mean lead concentration for all fugitive dust source areas is 28.400 ppm (2.8 percent). Source
areas near the smelter complex and throughout the river floodplain routinely exhibited levels in excess of
2 percent lead. Percent of sample solids to pass the ~mesh sieve ranged from 6 to 68 percent. averag-
ing 30 percent for all samples.
..
Air monitoring was used to investigate air contaminant tranSpon mechanisms. Air monitor locations
arc shown in Figure 5-2. Total Suspended Particulate (TSP) data are summarized in Table 5-6. Metal
content of filters collected on high dust event days (defined as days with TSP> 150 ~g/m3) is summarized
in Table 5-7. The 19 days in 1987 where blowing dust eventS were measured aa:ount for 43 percent of
the Total Suspended Particulates (TSP) loading for the entire 116-day sampling season. The single high-
est day (September 2. 1987) alone accounted for nearly 10 percent of the total monitoring season
loading. In 1989, the peak 10 days aa:ounted for 48 percent of the loading for the 9O-day monitoring
period.
Metal contaminant levels in house dustS are presented Table 5-8. House dust metal contamination, and
especially lead contamination. has decreased markedly since 1974. For aample, the mean house dust
lead concentration in Smelterville for 1974 was approximately 12.000 ppm (1.2 percent) and has
decreased to a mean level in 1988 that is one. tenth the 1974 value (1.200 ppm). Prior to 1981, during
smelter operations, the primary route for house dust lead contamination was airborne deposition of
smelter lead paniculate matter. Since 1981. house dust metals levels have been related to residential
soil concentrations. Contaminated dustS reach homes via deposition of windblown dusts or mechanical
tranSlocation of contaminated residential soils. Several studies indicate house dust lead levels in urban
and smelter communities (exclusive of those impacted by interior leaded paintS) are dependent on lead
levels in residential soils.
S.3 CONTA!\'UNANT MIGRATION
Soils within the site bave been contaminated by heavy metals, to varying degrees. through a combination
of airborne paniculate deposition. alluvial deposition of tailings dumped into the river by mining activi-
ties, and contaminant migration from onsite sources. Onsite sources include the smelter facility, indus-
trial compla, tailings and other waste piles. barren hillsides, and other fugitive dust source areas located
throughout the site. Since shutdown of the smelter, contaminant migration pathways of primary concern
are fugitive dust. flooding that redeposits tailings into residential areas, water erosion that results in
contaminated soil movement off of the hillsides, and human activities that either exacerbate the previous
pathways or directly contaminate residential soils.
The current primary contaminant migration mechanism is airborne deposition of contaminated dusts
from fugitive dust sources in and adjacent to the mining/smelting complex. Air monitoring information
collected during RI/FS activities and summarized in the RADER indicates that airborne dustS transpor-
ted into the Populated Areas have concentrations ranging from 1.000 to 20,000 ppm lead.
Total dry airborne paniculate deposition rates average 2...532 ~g/m2!hr and 1,768 ~g/m2Jbr at the
Smelterville Mine Timber and Kellogg Middle School monitoring sites. respectively (Figure 5-2). Wet
deposition rates averaged 484 and 487 ~g/m:/hr at the Smelterville and Kellogg sites. respectively. More
than 80 percent of the total paniculate and more than 90 percent of most metals deposition occurs as
-------
~LTfli
COW'lEJ(
i-
I'
,
I
\
IF
LEGEND
~
~
SITE PLAN
---.-
ROADS
RIVEIIS 4 STREAMS
o
.5
I I I I RAILROAD
MILES
.
A
NAAOS MONITOR
SPECIAL STUDY HIGH
VOLS/WIND fVENT
MONITOR
/
J/'
&'
-
. -
L.--, -,
. I ,
r---~' -l-r
: / '~~ /:"
IWAR6 ' R'I./'-
., ~ \
I /. .,L-..
Iu, /1 J
) ~ . r - I (},
'\.. ~ d! LEGEND
k~ / . II
s? i ~ 1 Pinehurst School
~l..,: J 2 Smelterville Sewage Lagoon
: I 3 Silver King School
L.' 4 Mine Timber Company
5 Drive-In Theatre/Truck Stop
6 Kellogg Visitors Center
7 Kellogg Middle School
8 Minerai Subdivision
9 Shoshone Apartments
10 Collocated Sampler.
Shoshone Apartments
Figure 5-2
AIR MONITORING LOCATIONS
-------
I Table 5-6 I
1m aud 1989 AIr ~oDllor1D1 TSP 1>888 ~~
1m ~oo.ltor Samber
1 2 3 .. 5 6 7 8 9 10
Minimum 13 10 a 10 4 11 6 3 5 6
Average 37 76 71 79 71 55 58 68 70 69
Maximum 589 353 821 915 311 7'22 904 691 690 744
Freqaeacy DtstrIbadoas
Loading lUnge
0 - 50 a 42 68 70 60 60 S4 S8 61 58 56
% 36 59 60 52 52 72 76 53 54 55
50 . 100 11 47 39 ::9 39 37 :.a 19 42 32 30
% 41 34 :.s 34 32 21 16 36 30 ::9
100.150 a 18 4 10 6 11 3 4 7 9 8
% 16 3 9 5 9 3 3 6 8 8
Over 150 n 9 5 7 11 8 5 5 6 9 3
% 8 4 6 9 7 4 4 5 8 8
1989 MoaJlor Samber
1 2 4 5 58 7 7. 8 9 10
(P~lO> (PMlO>
Minimum 10 9 3 6 6 0 2 8 0 ZO
Aver:lge 54 53 54 65 44 43 31 72 66 91
MaxImum 309 349 345 683 321 278 127 390 398 341
Freqaeacy Dtslribadoas
Loading lUnge
0.50 a 45 36 49 42 39 54 43 38 37 7
% 69 74 71 61 33 78 90 55 56 28
SO - 100 a 15 9 15 19 4 11 2 16 19 11
% 23 18 22 :S 9 16 4 23 29 44
100 . 150 a 0 0 0 3 1 0 3 6 6 ..
% 0 0 0 4 2 0 6 9 9 16
Over 150 n .5 .. 5 .5 3 4 0 9 4 3
% 3 3 7 7 6 6 0 13 6 12
-------
Table s.. 7
SDllUDlU"1 or Air Filler Metals Data (PfVm~
1987 and 1989 EveD' Monitoring
1987 Even' Monitoring MODltor Number
ADaIyte: Ar.ieDk 1 Z J 4 5 6 7 S 9 10
Minimum 0.004 O.OOS 0.004 0.004 0.002 0.003 0.005 0.004 0.003 0.003
Average 0.008 0.022 0.020 0.028 0.021 0.017 0.039 0.052 0.065 0.087
Maximum 0.014 0.176 0.089 0.103 0.095 0.131 0.415 0.287 0.382 0.625
AnaJy1e: Cadmium
Minimum 0.001 0.001 0.002 0.001 0.002 0.001 0.002 0.001 0.001 0.001
Average 0.002 0.005 0.012 0.008 0.010 0.007 0.015 0.018 0.032 0.039
Maximum 0.002 0.028 0.062 0.033 0.086 0.058 0.151 0.110 0.155 0.237
AnaIyte: Copper
Minimum 0.074 0.074 0.056 0.038 0.089 0.017 0.061 0.052 0.044 0.034
Average 0.204 0.169 0.165 0.109 0.144 0.066 0.130 0.145 0.203 0.184
Maximum 0.437 0.233 0.489 0.217 0.259 0.172 0.364 0.490 0.616 0.761
~ Le8d
Minimum 0.041 0.061 0.090 0.047 0.044 0.030 0.033 0.040 0.039 0.031
Average 0.224 0.703 0.997 1.067 1.059 0.382 0.656 1.214 1.799 Z.400
Maximum 1.713 3.914 8.591 4.955 4.394 2.874 6.263 7.825 10.007 15.460
1989 EnD' MonitoriDI MOD!lor Number
ADaJyte: Ar.ieDk 1 Z 4 5 58 (PMIO> 7 7. (PMIO> S 9 10
Minimum 0.004 0.004 0.004 0.004 0.003 0.004 0.003 0.004 0.008 0.012
Average 0.008 0.007 0.010 0.009 0.006 0.010 0.008 0.031 0.022 0.022
Maximum 0.027 0.010 0.032 0.019 0.Q17 0.028 0.021 0.098 0.059 0.060
AnaJy1e: Cadmium
Minimum 0.003 O.OOS 0.003 0.003 0.003 0.003 0.004 0.005 0.005 0.004
Average 0.006 0.006 0.007 0.006 0.005 0.005 0.006 0.015 0.018 0.024
Maximum 0.021 0.010 0.023 0.014 0.008 0.008 0.009 0.053 0.062 0.094
ADaJyte: Copper
Minimum 0.064 0.019 0.076 0.048 0.011 0.096 0.019 0.038 0.057 0.092
Average 0.133 0.119 0.132 0.073 0.045 0.354 0.053 0.121 0.176 0.134
Maximum 0.293 0.185 0.257 0.107 0.117 0.712 0.083 0.217 0.317 0.227
Analyte: Lead
Minimum 0.058 0.053 0.120 0.078 0.045 0.054 0.027 0.139 0.242 0.180
Average 0.091 0.103 0.607 0.542 0.193 0.202 0.124 1.544 1.033 1.179
-------
Table 5-3
Geomelric Meaa aDd Extreme HoUM Dus& Metal C4ocenb'aUons
1974, 197~ 1933. aDd 1988 Lead Health SIU"¥eY
(ppm)
As Cd Ca HI f") Sb ZD
1!774
Smelterville MCUI 8.0 113.0 . 17.3 10.583 185.0 5,432
(~%ile) (~ (503.0) (109.0) (30.394) (.w9.0) (17,154)
KdlogIWardDerl MCUI 5.7 6S.5 . 7.3 6.581 174.0 3.940
P3ge (~%ile) (~.3) (ZZ7.0) (66.6) (23.017) (844.0) (9.575)
Pinehurst MOD 3.3 :9.5 . 3.5 z..OO6 1:0.0 Z.o~
(9'S%ile) (1 S. 9) (73.5) (11.9) (50453) (312.0) (6.515)
1975
Smelterville MOD . .s2.0 . . 3.533 . .
(~%ile) (159.0) (21.807)
Kdlogg/WardDerl MCUI . 404.7 . . 4.573 . .
Page (~%ile) (12'1.0) (13.521)
Pioebun& MeaD . 25.0 . . 1.749 . .
(~%ile) (81.5) (6.694)
1913
SmeltetViUe Meaa . 63.3 . . 3,715 . 2.695
(~%ile) (12.5.5) (7.754) (5,070)
I
KdloufWardnerl MCUI . 37.6 . . 2.366 . Z.4043
Page (95%ile) (93.0) (7,840) (10.373)
Pinc:hun& MCUI . :4.6 . . 1.155 . 1.578
(~%ile) (68.3) (3.2SS) (3.301)
1981
Sme.ltetVille Mean 25.7 15.4 177.0 1.3 1.:03 18.9 1.394
(9'S%ile) (80.0) (52.0) (1.073.0) (7.8) (4,615) (64.0) (4.309)
KdJogJWardncrl MeaD ::6.3 15.6 167.0 1.3 1,450 rr.9 1,401
Page (9'S % i1e) (115.0) (47.0) (963.0) (4.6) (8,643) (147.0) (5.143)
Piaehun& Mean . . . . . . .
(9'S%ile)
NOTE:
.Data DOC available. Expoaure c:sUmates will employ cono:ntr:uioa (rom mOlt recent measurements. Source: IDHW 1974,
-------
dry deposition. The maximum dry deposition rate observed was 12.595 11g/m2Jhr at the Mine TLmber
site during the serond week of September 1988. Only four metals were observed to have dry deposition
rates consistently exceeding 1.0 l1g/m2Jhr. Those were iron, lead. manganese, and zinc with annual aver-
age deposition rates at the Mine Timber site of 132, 12.7, 8.6, and 11.3 l1g/m2Jhr, respectively. The max-
imum weekly lead deposition rate observed was 83.8 l1g/m2Jhr at the Mine Timber site, also occurring
during the serond week of September.
The highest deposition rates were observed during the weeks that also included the severe dust event
days with Total Suspended Particulates (TSP) > 150 11g/m3 shown in Table 5-9. The 1988 data confirm
that both total solids and contaminant particulate deposition seem to be event-related in a manner
similar to the TSP and ambient air metals concentration discussed in the last section. At both sites,
more than 2S percent of the total annual solids deposition occurred in four individual weeks in 1988.
Those included 1 week in each of May, August, September, and October. The same weeks accounted for
31 percent of total lead. 18 percent of total cadmium. and 29 percent of total arsenic deposition. The
1988 seasonal data also showed a frequency and magnitude of severe dust eventS (TSP >300 l1g/m3)
similar to that observed in 1987, but absent in 1989.
These resultS suggest that deposition, similar to TSP, is event-related with the bulk of deposited solids
and metals coming as a result of high wind speeds impacting barren dust sources in the vicinity of the
monitors.
Water erosion of hillsides near the smelter complex is a migration pathway to residential soil. particul-
arly in yards abutting hill slopes. Mass loading rates are high along these steep barren locations where
sheet and rill erosion with gullying are SignificanL Metals contentS on the hillsides average 5,000 ppm
lead.
Lead leachability from residential soils was determined by Extraction Procedure (EP) Toxicity and Toxic-
ity Characteristic Leaching Procedure (TCLP) analyses. These testS are used to determine if a material
should be considered a hazardous waste pursuant to the Resource Conservation and Recovery Act
(RCRA) and. consequently, subject to RCRA storage and disposal requirementS. ResultS showed 3 out
of 23 EP Toxicity samples exceeded the RCRA lead threshold level of 5 ppm. Two of the six TCLP
samples ex~ed the threshold level for lead.
-------
Table 5-9
lDdMd1aa1 FUters With TSP >150 IJoW'm3
SOftmher 1987 10 SOftmber 1988
SmelumDe M1De TImber I
Sample Date TSP Cd Cd ~ ~
(~m~ (~m~ (ppm) (~m~ (ppm)
1)9.Jv..AA 79<.1 0.0'" 1'i '.9 .$948
~~~~
-------
6 SUMMARY OF SITE RISKS
6.1 HUl\'1AN HEALTH RISKS
The RADER presentS a detailed discussion of the risk assessment for the Populated Areas. In the
RADER. both carcinogenic and noncarcinogenic effects of contaminant exposures are evaluated. A
Non-populated Areas risk assessment is being conducted in concen with the Non-populated Areas
RIJFS.
6.1.1 EXPOSURE ASSESSME1Vf
The contaminantS used in the exposure evaluation and risk assessment are aU metals that exhibit:
1) elevated concentrations in residential soils and dustS relative to background concentrations;
2) decreasing concentrations in environmental media with increasing distance from the industrial com-
plex; and 3) potential for human toxicity following incidental and chronic exposures. ContaminantS of
concern include antimony, arsenic, cadmium, copper, lead, mercury, and zinc.
Receptor populations at risk are identified as the current and past residentS of the Populated Areas of
the site. Three groups have been evaluated in terms of contaminant exposures and consequent risks.
These are:
1.
A general population of residentS that are assumed to live, since binh, under the condi-
tions represented by the contamination levels found since 1983 for a 70-year lifetime
(referred to as the current scenario which would also be a future scenario under the No
Action Alternative)
2.
A general population of residentS who were born in 1971 and were 2 years old during
the period of maximum exposure onsite and who remain onsite under current condi-
tions for a 70-year lifetime (referred to as the historical scenario)
3.
A sensitive sub population of children exposed to lead
Historical exposures, since 1971, were evaluated because of documented high contaminant concentra-
tions during 1973-1975. Airborne lead concentrations were approximately 100 times greater during this
period than current levels. Consideration of these exposures is critical for evaluating the potential
chronic risks of metal contaminantS on the population.
Both the current and historical populations (numbers 1 and 2 above) are representative of baseline con-
ditions-those conditions under which no remedial action has been undenaken (the No Action Alterna-
tive ).
The principal exposure media and associated receptor pathways characterized for the evaluation of base-
line human health risk for the typical resident in the Populated Areas of the Bunker Hill site are:
.
Ingestion of residential surficial yard soils
.
Ingestion of house dustS
.
Inhalation of air particulate matter
.
Consumption of national market basket variety produce (foodstuffs available on super-
market shelves representing food of average consumers) and water ingestion from
-------
public water supplies (public water is supplied from a surface water source outside site
boundaries)
Additional exposures that could be experienced by members of the population who engage in potentiall
high-risk activities are evaluated as incremental exposures. The following incremental exposures were
evaluated:
.
Consumption of contaminated local groundwater
.
Ingestion of Other soil/dust at extreme (95th percentile concentration) residential soil
and house dust concentrations
.
.
Ingestion of extreme amounts (1 gmJday) of soil and dust during childhood (typical of
"pica-type" behavior)
.
Consumption of local fISh from the Coeur d' Alene area
.
Consumption of local vegetable garden produce
.
Inhalation of outdoor air paniculate matter during episodic. high wind events
To determine an individual's level of risk resulting from panicipation in potentially high-risk activities,
the appropriate incremental risk(s) were added to the baseline estimate. If an individual does not
engage in any of the incrementaJ activities evaluated. then the risk to that individual would be the base-
line estimate. The incremental exposure analysis can be used to determine the Reasonable Maximum
Exposure scenario for the Populated Areas.
Exposures and consequent risks were evaluated for each of the tWo baseline periods (current and histo
cal) in three separate areas (Smelterville. KellogglWardnerlPage. and Pinehurst) for the average or typi-
cal population. The risk assessment was complc:ted assuming current land uses would continue to be
residential.
Lifetime or chronic exposures were evaluated for the typical resident by estimating contaminant intakes
using average media concentrations (see Table 6-1). For this evaluation, arithmetic mean concentrations
for exposure media were used to represent average or typical long-term exposure levels. For residential
soil and house dust exposures. geometric mean concentrations were calculated and used for evaluating
typical long-term exposures. Geometric mean values for these media are expected to be more represen-
tative of average exposures because of the statistical distributions exhibited by soil and house dust metal
concentrations.
Chronic exposures at extreme levels are not expected for the typical residenL Therefore, chronic expo-
sures to extreme concentrations of site contaminants are not evaluated in the baseline chronic assess-
menL Extreme media concentrations represented as 95th percentile levels were evaluated as incremen-
tal and subchronic exposures.
The traditional approach for risk characterization associated with lead exposure is currently inappro-
priate because an acceptable Reference Dose (RID) for lead is not available. Therefore, risk character-
ization for subchronic lead exposure was accomplished by using observed childhood population blood
lead levels and environmental media lead concentrations collected over the last 17 years in an integrated
uptake/biokinetic dose-response model. The model was used to relate childhood blood lead levels to
contaminated media exposures. Model inputs and criteria were selected and validated using site-specific
data as described in the RADER.
-------
Table 6-1 presentS a summary of contaminantS of concern. exposure routes and sources, and scenarios
addressed in the exposure evaluation and risk assessmenL
Table 6-1
Contaminants Evaluated, Exposure Routes and Soan:es,
and E:rposure SuDari08 Addftssed 10 the RIsk As..-cnvut
Cootaminanla EYalua&ecl
Antimony
Arsenic
Cadmium
Copper
Lead
Mercury
Zi..oc:
Exposure Roa1a and Soan:a
Chronic
Baseline:
lnhalatioa-Airlpankulates
lngestioa-SoiJ
Ingestioo-House dust
Ingestion-Other soils and dusts
IngesUon-Drintin& Water (Municipal Water System)
[ngcstion-Mart.ct basket produce
Incrementa!:
[ngcstion-Loc:al fish (L1ke Coeur d'Alcnc)
Ingestion-I...oc:ally growa garden produ.cc:
Ingestion-Drinking Water (onsite groundwater)
[ngcstioa-Ex1r'eme soil/dust c:oosumption rate, "Pica Behavior' (as a child)
[ngestion-Othcr soils and dusts (mmmum estimated aposure)
Subchronic
Dose-Response Modeling (or Lead
Exposare SceD8ri08
HistoricaJ-Smdterville
CUrmlt-Smdtaville
HjstoricaJ-KclJogg/PagelWardDcr
Cum:nt-lCdJoggIPagelWardner
HiItorical-Pinehurst
Current-Pinehurst
Background
6.1.2 TOXICJ1Y ASSESSMENT
A detailed discussion of the toxicity of site contaminantS is presented in Section 3.5 of the Protocol Doc-
umenL Table 6-2 provides a summary of the most sensitive effects for each of the seven site contami-
nantS of concern.
-------
~
Table 6-1
Sammary ot ~08& SeJ.itift Adftne Health Erl'eets of SII.. Con.....t.....ca of CAacena
~oDC8l'dDogenJc Etfe
-------
the cancer eventS due to other causes. The current U.S. cancer rate is one in four. Therefore, in a pop-
ulation of 1 million people. 250,000 cancer eventS are predicted. Under a 1O~ risk scenario, 250,001
cancer eventS would be predicted.
Tab&e 64
NoDCal"dDogeak Elfec1s aDd Associated IUDs
(or SUe Con&amiDaDts or Coacem
RID
Chemk&I Ezposare RoaSe Pathology (~)
Antimoay Ora! Gt Irritatioo 4 x 10-4
Ancnic Ora! Skin Lesions 1 x 10-3
Cadmium Ora! Renal Dysfunction' 1 x 10.3
Food
Water S x 10-4
Capper Oral Gt Irritation 1.3 mg/L
Lead InhaJation and Ora! Various, including Renal Unavailable
Dysfunction, Anemia and
Ncurobchaviora! Dcficicn-
cies
Mercury Ora! Renal Dysfunction 3 x 10-4
zmc Ora! Anemia 0.20
Chcmic:a1I with common effccu include:
Cadmium, lead. and mercury for renal toxicity.
Lead and ziDc ror anemia.
Antimoay and copper for production of gastrointcstinaJ (GI) irritation.
ResultS of the chronic exposure and risk characterization indicate that excess (above background) carcin-
ogenic risk is associated with baseline exposures and consequent intakes for arsenic and cadmium in air.
Total baseline (70-year lifetime) risk to lung cancer, due to inhalation of arsenic and cadmium under
current site conditions. is from 2 to 32 times greater than for offsite background. Under the historical
scenario, risk to lung cancer was twO to six times greater than the current scenario for the same
communities. Baseline cancer risk estimates indicate that the typical population exceeds U.S. EP A's
acceptable range for cancer risk (10-4 to 10~.
Acceptable levels of risk to lung cancer may never be attained at any future arsenic and cadmium air
levels for those individuals who have had oonsiderable historical and cumulative exposures. Tumor
regisuy data suppon the presence of a disease-causing agent for the increased occurrence of respiratory
cancers in the area.
Baseline carcinogenic risk due to site exposures is approximately 30 percent greater than background
carcinogenic risk (9.8 x 1O~. Baseline carcinogenic risk in oonjunction with the consumption of site
groundwater in Smelterville and Kellogg due to arsenic intakes oould result in a doubling of the risk
associated with background exposures. Excess health risk due to arsenic in groundwater makes this
source unsuitable for drinking in many areas of the site. Groundwater is not currently used as a munici-
pal drinking water source.
Table 6-5 presentS a summary of the baseline and incremental carcinogenic risk estimates.
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Table 6-5
Summary of Baseline and Incnmental Carcinogenic Risk EstimateS-
Loc:a1 Estftme Total,
Garden ~ SoIJ/Dast Other All
Scenario LocatJoa Contaminant B.as.e LIDe Local Flsb V~tables G I"OG.DdwaI.er lD2estJoa SoUlDust Intakes
HisIoric;:aj Smeltcrville Ancnic 1.3x10.3 6.7xl04 3.3xlO.S S.WO.5 2.1%10.3
Cadmium lAx104
ToW lo41l0.3 6.7xl04 3.3xlO.S 5.WO.5 2.WO.3
K.e1JouI Anenic: 1.51l 0.3 1.9x104 9.51l0.S 3.3110.5 1.8.x10.3
Ward.ncr/Page Cadmium 1.1.1104
ToW 1.6xl0.3 1..91104 9.5x10.5 3.3xl0.5 1.3x10.3
?indlW'S1 Arsenic 1~0.3 6041l0'S 3.1.110.5 1.3x10.3
Cadmium 6.3x1O.5
ToW 1.3xl0.3 6.-b:l0.S 3.l.Il0.S 1.3xl0.3
Current Smelterville Anc11ic 1.1.110.3 6.7xl04 2.2xl04 3.l.Il0'S 2.0xl0.3
Cadmium S.3xl0.5
ToW 1~10.3 6.7xl04 2.2x104 3.WO.S 2.Ox10.3
KdJouI Ancnic 1.WO.3 1~04 1.8.x104 2.4xlO.S 1.51l0.3
Waroner/Page Cadmium l.3xl0'S
ToW 1.1.110.3 1.9x104 1.8:1104 2.41:10.5 1.5x10.3
PinebW'S1 Anenic: 9..3z104 6.4xlO.S 3.1.I10'S 1.1xlO.3
Cadmium 1.4xl0.5
ToW 9.8:1104 6.4%10.S 3.WO.S 1.1.110.3
. Contaminants and media Cor wbic:b risk is DOC estimated is due 10 lack of eitbcr aD appropriate CPF mdtor media CODcentrations from
wbicb intakes can be estimated. CPFs are available only Cor ancnK: (on! and inhalatioo) and c::admium (inha.Latioa 0I1!y).
6.1.3.2 Nonc::ardnogenic Risk
Potential concern for noncarcinogenic effects of a single conf;lmin;lnt in a single medium is expressed as
the hazard quotient (HQ). By adding the HQs for all conf.amin;lntS within a medium or across all media
to wbich a given population may reasonabty be expo5ed. the Hazard Inda (HI) can be generated. The
HI provides a useful reference point for gauging the potential significance of multiple contaminantS
exposures within a single medium or across media.. Exces.s risk is determined to be where the HI is
greater than or equal to 1.0.
All estimated basd1ae DOoc:ardnogenic risks for specific toxic endpointS and target organs resulting from
oral intakes of site confamin;ll'ltS of concern have been determined to be acceptable (HI < 1).
Potential activities that could result in unacceptable risk to noncarcinogenic disease are associated with
metal intakes resulting from consumption of site groundwater, excessive soil and dust ingestion by chil-
dren. and consumption of local garden produce.
Table 6-6 presentS the summary of excess risks evaluated in the noncarcinogenic risk assessment.
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Table 6-6
Summary or Exposure Routes, Scenarios, and
Potentially High-Risk Activities That Could Result in
Unacceptable Chronic Risk to Noncarcinogenic Disease
E;
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6.1.3.3 Sobchronic Exposure
The most recent lead health survey of area children indicates that CUrTent blood lead levels for many
children exceed levels at which adverse health effectS are associated. In 1990, 2 of 362 children had
blood lead levels exceeding 25 ,ug/dL Fifty percent (50%) of the children within an approximate Z-mile
radius of the industrial complex had. blood lead levels exceeding 10 }.Lg/dl. Thirty percent (30%) of the
children within the 2- to 3-mile radius of the industrial complex had blood lead levels exceeding
10 }.Lg/dL
CDCs 1985 Health Advisory for Blood Lead Levels states that "a blood lead level in children of 25 }.Lg/dl
or above indicates excessive lead absorption and constitutes grounds for medical intervention." Recent
information indicates that adverse health effectS are associated with blood lead levels at 10 to 15 }.Lg/dl.
or possibly lower. CDC is expected to establish 10 }.Lg/dl as the level above which action should be
taken. In addition. ATSDR is supportive of the goal of reducing childhood blood lead levels to below
lO}.Lg/dL
A review of past exposures and health survey data at the Bunker Hill site indicates that during extreme
exposures in the early to rnid-l97Os, up to 80 percent of the children exhibited blood lead levels that are
associated with adverse neurobehavioral development that persists into young adulthood. Additional
concern for past lead exposures (prior to smelter closure in 1981) is due to the potential release of lead
from normal bone resorption during pregnancy and lactation and the resultant pre- and post-natal expo-
sures to children who are born today of mothers who were exposed as children in the 19705.
Subchronic exposures and consequent intakes could increase health risks in the short term to levels well
above those estimated for baseline chronic risks. Ingestion of extreme amounts of soil and dust during
childhood (ages 2 to 6 years), characterized as "pica-type" behavior, could yield up to 10 times greater
metal intakes than for the typical child. These extreme intakes due to soiVdust ingestion could amount
to approximately 2 mg Pb/day, resulting in dangerous blood lead increases in young children. "Pica-type"
behavior could present extreme risk to this highly susceptible sub-group of the population. and requires
control it observed..
Consumption of local garden produce can yield extreme intakes of cadmium. lead and zinc. Up to
220 times as much lead can be ingested from the consumption of local garden vegetables grown in
Smelterville and Kellogg versus that associated with the consumption of national market basket variety
produce. Children and pregnant women (as SUrTogates to the fetus) are most susceptible to the adverse
effects associated with consequent lead intakes. Up to 62 times as much cadmium can be consumed in
local garden produce versus market basket variety produce. thus presenting unacceptable chronic and
subchronic risk to renal disease.
6.1.4 HUMAN REALm RISK SmfMARY
In summary. the conclusions of the RADER state that CUrTent site conditions present an environment.
where there are excessive risks associated with several different exposure pathways. These are:
.
Carcinogenic risk associated with exposure to:
Arsenic via potential groundwater consumption
Arsenic and cadmium via inhalation
.
Chronic noncarcinogenic risk associated with exposure to:
Arsenic. cadmium. and zinc via potential groundwater consumption
-------
Antimony, cadmium, mercury, and lead via excessive soil and dust ingestion
(characterized by .pica-type. behavior)
Cadmium and lead via local garden produce consumption
.
Subchronic noncarcinogenic risk associated with exposure to:
Lead via ingestion of soil and dust
Cadmium, lead, and zinc via local garden produce consumption
Subchronic lead absorption among young children is the most significant health risk posed by this site.
The major routes for lead absorption are:
.
Ingestion of contaminated soils in residential yards and other residential environs
.
Ingestion of contaminated house dusts that are resultant from tracking of residential
soils and deposition of airborne particulate
.
Inhalation and ingestion of airborne particulate matter derived from fugitive dust
sources throughout the site
6.1.5
THE 1,000 PPM THRESHOLD CLEANUP LEVEL
A remedial action objective for this operable unit is to decrease the exposure to lead-contaminated resi-
dential soils such that 95 percent or more of the children in the area have blood lead levels below
10 JLg/dl and that less than 1 percent have blood leads greater than 15 JLg/dl The 1,000 ppm lead
cleanup threshold level selected for yard soil remediation at Bunker Hill is a site-specific and media-
specific value chosen to meet these objectives. This level is not a target exposure concentration.
Rather, it is the maximum soil lead level that any child may be exposed to in his or her home yard. This
should not be construed to suggest that this level is health protective for soils at other sites, or other
soil and dust media at the Bunker Hill site. A child living on an unremediated yard of 1,000 ppm is
estimated to have a 0.1 to 2.5 percent (depending on various assumptions) chance of exceeding 15 l1g/dl
blood lead in the Bunker Hill post-remediation environmenL The following are several reasons why this
solution applies only for residential yard soils and only at this particular site:
Response Rate: The response rate value for this site was arrived at after extensive review of
epidemiologic and environmental data collected at the site for more than 15 years. Analyses of
those data suggest that the dose-response relationship between contaminated soils and dusts and
resultant blood lead levels in children is about half that observed at other lead-contaminated
sites. Whether the lesser response rate is due to reduced intake (lower soils and dust ingestion
rates) or reduced uptakes (lesser absorption of ingested lead in soils) cannot be discerned from
the data. The selection of the 1,000 ppm threshold level assumes the latter (Le., reduced
absorption rates at this site).
Total Lead Intake: Predicted blood lead levels resultant from remedial activities are based on
total lead intake from all media. The four principal pathways are lead in diet, drinking water,
air, and soils and dusts. The effectiveness of the 1,000 ppm threshold level for yard soils is
dependent on several assumptions regarding reduced intakes along other pathways. Some of
those assumptions are based on assessments of other remedial activities on the site and substan-
tial reductions in dietary intake achieved from nationwide lead reduction initiatives. Those
assumptions may not apply to other sites.
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Composite Soil/Dust Lead Concentrauons: Analyses presented in the RADER suggest that the
romposite roncentrations of lead in all the soils and dusts ingested by children must be reduced
to ioo to 1.200 ppm at this site to meet the remedial action objective of less than 5 percent of
children having a blood lead of greater than 10 }J.g/dL There are several contnouting sources to
this overall soil and dust loading. Those include yard soils, house dusts, road dusts, play area
soils, fugitive dust sources, and other soils in the community where children may rongregate.
Residential yard soils are an important romponent of the overall soil and dust loading. A sub-
stantial portion of children's exposure results from direct contact in the yard. A substantial
portion of house dust loading results from yard soils uansponed into the home and additional
children's exposure results from visits to yards other than their own home. Yard soils may also
be a source of contaminated dusts circulating through the community via air, water, and
mechanical pathways. Removing all yard soils greater than 1,000 ppm will have positive effects
along all thes;e pathways and routes of exposure. However, achieving the remedial action objec-
tives will require additional activities among the soil and dust sources other than yard soils.
Those actions are specific to this site and may not be applicable to other locales.
Distribution or Yard SOU Lead Concentration: The effectiveness of the cleanup strategy in
meeting remedial action objectives depends on the post-remediation distnoution of contaminant
levels. That c1istnoution will be site-specific and, likely, inapplicable to other 1000tiOns. The
imposition of the 1,CXX) ppm cleanup threshold at the Bunker Hill site will result in remediation
of more than 75 percent of the yards in most residential areas. The mean yard soil lead roncen-
trations in area communities will be reduced from nearly 3,000 ppm to less than 200 to
300 ppm. This represents a tremendous reduction in tOtal environmental lead loading in the
community and should have positive effects in other media as well Substantial benefit will
result in the form of reduced exposure from several ~urces.
Actual or threatened releases of hazardous substances from this site, if not addressed by implementing
the response action selected in this ROD, may present an imminent and substantial endangerment to
public health, welfare, or the environmenL
6.2 ENVIRONMENTAL RISKS
This Record ot Decision addresses the remediation ot residential soils within the. Populated Areas of the
Bunker Hill Superfund Site. There are no critical habitats or endangered species or habitats affected by
residential soils contamination or anticipated effects caused by future remediation. An ecological risk
assessment is being conducted as pan of the Non-populated Areas R1/FS.
The urban component oC the ea>system at Bunker Hill bas been impacted by historical mining and
smelting activities. The average heavy metal concentrations in residential soils and community road
shoulders are higher than on the hillsides portion of the site. Many oC the residential soils have metal
concentrations capable of inducing toxicological effects on soil micnH>rganisms, invenebrates, and
plants. Comparative concentrations in various other soil types have resulted in reduced productivity,
yields, decomposition. and nutrient cycling rates. Other animal5. that inhabit the urban areas such as
field mice and squirrels. as well as cats and dogs, are suscepn1>le to ingestion of residential soils with an
increased risk of chemical stresS.
Management of soil and vegetation at Bunker Hill can facilitate natural and favorable conditions within
the urban ecosystem by reducing the mobility of contaminants and their potential for inducing chemical
stress. The replacement of residential soils and vegetation is expected to enhance the micro-habitat
niches for the flora and fauna that use them.
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7 DETAILED DESCRIPTION OF ALTERNATIVES
This proposed cleanup action involves residential yards, an area that is typically used for many different
activities and purposes. While it is important that the cleanup action block the routes by which people
come in contact with contaminants in the soil, it is also important that the cleanup action allow
residents to use their yards for their many purposes. For example, while a concrete or asphalt layer
would block the pathway between the contamination and residents, it would make it impossible for
residents to use their yards for typical activities, such as planting and gardening. Therefore, except for
the No Action Alternative, all of the alternatives are designed to reduce human exposure to
contamination. while maintaining the integrity of the individual yards.
7.1 ALTERNATIVE I--NO ACTION
The No Action Alternative provides a baseline for comparing against other alternatives. The site would
be left in its current condition. Existing institutional controls, such as the Health Intervention Program,
would be discontinued. Because no remedial activities would be implemented with the No Action Alter-
native, long-term human health and environmental risks from residential soils at the site would be
essentially the same as those identified in the RADER:
.
Significant health risks to young children associated with exposure to ingestion of con-
taminated soil, ingestion of contaminated house dusts, and inhalation and ingestion of
airborne particulate matter would maintain currently unacceptable health conditions
and could result in dangerous blood lead increases in young children.
.
Excessive soil and dust ingestion by .pica-type. children could result in toxic effects due
to antimony, cadmium, and lead.
.
Consumption of local produce can increase intakes of cadmium, lead, and zinc, resulting
in neurological and renal disease.
Unacceptable high blood lead concentrations in some children would probably continue and the poten-
tial for increases in blood lead concentrations could increase because of the termination of the health
intervention program.
Environmental monitoring would be conducted under the No Action Alternative. The purpose of the
monitoring would be to detect changes in environmental conditions over time. Environmental monitor-
ing would occur for the following media:
Media Parameters
Air Suspended particulates, Pb and As concentrations
Residential Soils Contaminant metals concentrations
Sampling locations would be consistent with previous sample collection sites to provide a basis for
historic comparisons. In addition to monitOring environmental media, it is expected that childrens'
blood would continue to be screened for lead.
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7.2 CO~nvION CO~1PONENTS OF ALTERNATIVES
3--V ARIABLE CUTIREl\'IOVEIFILUDISPOSAL;
5--S0D RE~lOVALISOD REPL\.CEl\'IENT/DISPOSAL;
6--DEEP REl\-lOV AUFILUDISPOSAL; AND
8-- VARIABLE CUTfREl\'IOVEIFILUrREA T/DISPOSAL
All of the remaining alternatives have componentS in common (use of institutional controls, revegeta-
tion. dust suppression. e:tC3vatiowbackfill. extent of remediation. disposal, and monitoring). Although
the description of these componentS is not repeated in the discussions for each alternative, differences in
their planned implementation are identified where appropriate. ARAR.s for all alternatives are similar
and are discussed in Section 10. Each of these common componentS is discussed below.
1.2.1 INSTITUTIONAL CONTROLS
[nstitutional controls would be implemented to a certain degree with each alternative. The reliance on
institutional controls is dependent on the remedial action technologies employed and their long-term
effectiveness in protecting human health and the environment. The detailed evaluation of the proposed
institutional controls are included in the document entitled An Evaluation of Instirutional Controls for the
Populated Areas of the Bunker Hill Superfund Site, which is part of the Residential Soils Administrative
Record.
The range of institutional controls consistS of the following componentS:
.
Deed notices
Public eduC3tion
ExC3vation regulations and permitS
Health intervention program
Contaminated soil collection system
Oean soil supply system
Post-cleanup administration and evaluation
Sod maintenance ordinances
Lawn maintenance contracting
.
.
.
.
.
.
.
.
7.2.2 REVEGETATION
Revegetation of residential yards is a component of each alternative. The lawn areas of remediated
yards would generally be revegetated with sod. Steep hillsides and other remediated areas not currently
planted with lawns (such as vacant lotS) would be stabilized and hydroseeded with native grasses. Native
grasses require less maintenance and are more tolerant of the local climatic conditions. If preferred by
a property owner, hydroseeding with native gras.ses could be substituted Cor the sod. To the extent
practiC3ble. all yard landsC3ping would be returned to itS original condition.
7.2.3 DUST SUPPRESSION DURING RE.\fEDIATION
Dust suppression measures would be implemented throughout the remediation process to reduce
exposure of workers and residentS to airborne contaminantS. Dust suppression would include:
.
Watering of residential yard areas prior to excavation activities
.
Continued watering during excavation, as necessary
.
Placement of tarps or covers over excavated materials
-------
.
Use of tarps or covers over truck beds to reduce blowing dust and spillage during
transportation to the waste repository
.
Daily cleanup of all spilled or tracked soils from sidewalks, roadways, ete.
Appropriate air monitoring would be conducted to identify the occurrence of contaminant migration
during remedial activities. Any exceedances of the standards would result in immediate implementation
of additional dust suppression measures or a shutdown of construction activities.
7.2.4 EXCAVATION/BACKFIWCOVER
For all alternatives, remediation of residential yards would be completed by either covering with a layer
of uncontaminated soil or by removing and replacing contaminated soil or sod with uncontaminated
materials.
A range of alternatives was developed to provide decision makers with several options. Alternative 5 is
an option with minimal soil removal and replacement. A 12-inch removal and replacement is presented
in Alternative 3. A 6-inch soil barrier was considered during the development of Alternative 3.
However, it was concluded that a 6-inch depth is insufficient to provide a viable option as a barrier
technology in a residential area, if the underlying material is contaminated. This is because a 6-inch
barrier could be penetrated by such common occurrences as a digging dog, a homeowner planting bulbs,
or children's play activities. To complete the range of alternatives, Alternative 6 was developed to
evaluate deep removal of contaminated materials.
7.2.5 EXTENT OF REMEDIATION
For all of the alternatives, the areal extent of remediation would be consistent. For each residential
yard, the exact nature of the remediation (e.g., how much sod to replace, which bushes to remove, ete.)
would have to be considered on a case-by-ca.se basis. However, for consistency, the following areas
would generally be remediated within each yard:
.
Sod areas
Roadway shoulders (if curb and gutter is not present) to the extension of the lot lines
Alleys (if unpaved) to the extension of the lot lines
Planters and other landscaped areas
Garden areas
Unpaved driveways
Garages with dirt floors
Storage areas
. .
.
.
.
.
.
.
In short, remediation would occur in any area within and adjacent to the residential yard where children
could play and could potentially come in contact with contaminated soils. Areas that currently provide
a barrier from the underlying soils (such as paved sidewalks and driveways) would not require
remediation.
7.2.6 DISPOSAL
The proposed site for disposal of contaminated residential soils for all alternatives is the Page Ponds
tailings impoundment. Page Ponds is an old tailings impoundment that is currently the site of the South
Fork Coeur d' Alene Sewer District treatment facility. On either side of the sewage lagoons are
"benches" that are primarily tailings, denuded of vegetation, and consequently are a source of windblown
dust to the valley. The benches (east and west dikes) is the area recommended for the residential soils
repository. Consolidation of residential soil and sod onto the Page benches will contribute [0 reducing
fugitive windblown dust throughout the valley.
-------
Since the volume of material requiring disposal will vary with the selected alternative. the volume of soil
wastes may exceed the capacity of the Page benches. In that case, an additional disposal site will need to
be used to supplement the disposal capacity of Page Ponds since the approximate capacity of Page Pon
is 860.000 cubic yards. .
The disposal site will have an impermeable cap or cover (i.e., one that is designed to minimize migration
of contaminantS) placed during closure. The long-term management of the area will include
maintenance of the cover and groundwater monitoring. In addition, aa:ess restrictions and land use
restrictions and/or notices will be used to ensure that future use of the property is not incompatible with
a residential soils repository.
1.2.1 ENVIRONMENTAL ~IONITORrnG
Regardless of the alternative selected, contaminated materials win remain within the residential areas of
the site. Alternative 6. which requires deep excavation to remove materials, will most likely not remove
all contaminated material. Therefore, environmental monitoring will be continued at the site for an
indefinite period. It is estimated that environmental monitoring of fugitive dust and residential soil and
litter would continue. Monitoring will occur at previous sampling locations to provide a basis for
historical comparisons. It is expected that blood lead levels would also be monitored. For cost
estimating purposes, it is assumed that a greater extent and frequency of sampling will be required in
Alternative 5 than the other alternatives, since it would place only a sod layer barrier betWeen the
contaminantS and the residentS.
7..3 AL TE&'lA TIVE 3-- VARIABLE CUTIREl\'IOVEIFILUDISPOSAL
Alternative 3 consistS of the following options:
.
A 2.inch gravel barrier and lO-inch cover without soil excavation
.
A 2.inch gravel barrier installation, and a lO..inch soil replacement after excavation and
removal of up to 12 inches o( soil (y3rds would be above grade (or excavations less than
12 inches)
Both options are similar in that each incorporates a combination of a visual barrier and a separate soil
cover. They differ in where they can be applied to a residential yard because of drainage and home-
owner considerations. Whatever the excavation depth, this alternative will result in the placement of a
minimum of 12 inches of clean material
The option of a graveVsoil cover barrier without additional soil excavation is preferred because it mini-
mizes the volume of contaminated soil requiring disposal. A 2-inch clean gravel layer with a lO-inch soil
cover would be selected for implementation at residences in which the foundation is high enough in
relation to c:xi.Sting grade to allow itS use. where permission is granted by the respective property owner,
and at residences where drainage is not a problem.
The cover would consist of 2 inches of clean gravel overlain by 10 inches of clean topsoil from an offsite
borrow source. The gravel layer would provide a visual and physical barrier indicating to the landowner
that the bottom of the remediated soils had been reached, isolating the underlying contaminantS from
inadvenent exposure. Also, the gravel layer would act to some degree as a capillary barrier to the sub-
surface migration of metals. Clean fill would be revegetated by sodding. To the eXtent practicable, the
yard landscaping would be returned to itS original condition.
-------
A 24-inch layer of topsoil would be placed in established garden areas since some plant roots and tubers
extend below 12 inches, but generally less than 24 inches. Future activities that penetrate the 12.inch
cover, such as utility line installation, planting of larger trees and shrubs, and basement or foundation
excavation, would be controlled through ordinances regulating excavation, as detailed under
Section 7.2.1, Institutional Controls.
For those residences in which a simple gravel barrier/soil covering cannot be implemented, contaminated
soils would be excavated and replaced with a clean gravel/topsoil barrier. Various depths of excavation
and fill would be necessary based on site conditions:
.
Excavate 12 inches; replace with 2 inches of gravel and 10 inches of soil.
.
Excavate less than 12 inches; replace with 2 inches of gravel and 10 inches of soil
(finished grade would be above existing grades).
.
Excavate 24 inches, replace with 2 inches of gravel and 22 inches of soil (for established
garden areas).
The choice of excavating to less than 12 inches is dependent upon the yard grade in relation to the
house floor grade and depth of contamination. Under most circumstances, building codes do not allow
yard grades to be higher than house floor grades. The next step to implementing this alternative would
be to excavate soils to the selected depth below the ground surface. All sod or other surface coverings,
except for pavements, would be removed and disposed of along with the soil. Large trees (4-inch
diameter and larger) and shrubs (taller than 3 feet) would be saved, if possible. Trees and shrubs left in
place would be trimmed back and contaminated soil would be removed by hand from around the roots.
The 'clean' soil used to replace the excavated soil would meet borrow source and landscaping specifica-
tions. Backfilled areas that were previously lawn areas would generally be revegetated with sod. In
some backfilled areas it may be more appropriate to revegetate using hydroseeding with native grasses
(steep hillsides, vacant lots, ete.) To the extent practicable, however, the yard landscaping would be
returned to its original condition.
The volume of material to be disposed is estimated to be 640,000 cubic yards.
Regardless of the option employed under Alternative 3, environmental monitoring of fugitive dust,
residential soils, house dusts, and periodic blood lead analyses of residents would be continued.
Monitoring would occur at previous sampling locations to provide a basis for historical comparison.
7.4 ALTERNATIVE 5--S0D REMOVAUSOD
REPLACEMENT/DISPOSAL
Alternative 5 consists of contaminated sod removal and replacemenL
Residential yards would be cleared and grubbed, which includes removal of sod, brush, and stumps.
Alternative 5 would not include any removal of contaminated soils or replacement with clean soils in
grassed areas. The clean sod would be placed over the top of contaminated soils. To the extent
practicable, the yard landscaping would be returned to its original condition.
All areas not to be covered with new sod would be remediated using excavate/replace/dispose techniques.
Areas such as planters and graveled areas would be excavated to 6 inches. Garden areas would be
excavated to 24 inches and backfilled with clean soil, similar to Alternative 3. Contaminated materials
would be disposed of in the Page Ponds Repository. The estimated volume for disposal would be
-------
203.500 cubic yards. Oe:m fiU from an offsite borrow source would be used to replace the excavated
materials.
Future activities that penetrate the clean sod layer, such as utility line installation. planting of trees an
shrubs, and basement or foundation eXClvation, would be controlled through ordinances regulating
excavation. as detailed under Section 7.2.1. Institutional Controls. Additional institutional controls
would have to be implemented with Alternative 5 to maintain the long-term viability of the sod layer.
These controls would include ordinances requiring homeowners to water and maintain the replacement
sad to an acceptable leveL Additional inspection would be required by the various government entities
to ensure that the sad maintenance ordinances were effectively enforced. A professional lawn
maintenance company would be retained to advise and assist the homeowners with proper sod
maintenance. The lawn maintenance company would also provide and apply the necessary fertilizers and
chemic:lls to ensure the health and vigor of the sod barrier. Environmental monitoring after remedia-
tion would be continued.
7.5 ALTERNATIVE 6--DEEP REl\10VAUFILUDISPOSAL
Alternative 6 includes removal of contaminated soil to a depth of 7 feet and replacement with clean
material. Although this is a deep removal, there may be contaminants left in place in some areas.
The institutional controls requirement with this alternative would be considerably reduced. Since con-
taminated residential soils would be removed to a depth oC 7 feet. future institutional controls for
residential yards would be minimized. The public information and health intervention programs would
be required. but at a reduced level. Environmental monitoring would be continued.
For residential yards, aU contaminated soils would be excavated and replaced with clean soil. The depth
oC excavation would be determined on a site.by-site basis. The excavation would extend to a depth a
which the threshold level was reached or to approximately 7 feeL
Prior to exc:lvation activities, the depth and concentration oC lead contamination would be determined in
areas to be remediated. Selection of sampling strategy and depth of soil removal would be a function of
the remedial design/remedial action process.
Once excavation and fill depths are selected. the next step to implement this alternative would be to
exc:lvate soils to the selected depth below the ground surface. All sod or other surface coverings would
be removed and disposed of along with the soil. The need to remove and replace pavements and side-
walks would be determined on a c:lSe-by-C3Se basis. All trees and shrubs would be removed. The soil
used to replace the exc:lvated soil would consist oC clean soil from an offsite borrow source. Backfilled
areas would be revegetated. To the extent practicable, the yard landsc3ping would be returned to itS
original condition.
Soil. sod, and other materials that are removed would be disposed at an appropriate disposal site. It is
estimated that Alternative 6 would generate 4A5 million cubic yards of wastes. Preliminary estimates
indicate that approximately 860.000 cubic yards of wastes could be disposed of at the Page Ponds
Repository. This means that approximately 3.6 million cubic yards oC wastes would have to be disposed
of at another site, if Alternative 6 is implemented. .
Special c:lre would have to be taken when excavating near foundations. basementS, and utilities to avoid
damage to existing structures and facilities. Temporary shoring and supports may be required. It may
be advantageous to remove and replace utility lines, rather than shore and support them during
construction.
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Because of the inconvenience to the residents and potential liabilities associated with this alternative, the
residents would be temporarily relocated during construction. The relocation would be to local motels
or hotels and would be expected to last 2 to 3 weeks for an average residential yard remediation.
7.6 ALTERNATIVE g--VARIABLE
CUTIREMOVEIFILL{fREA T/DISPOSAL
Alternative 8 is identical to Alternative 3 except that the excavated soil would be treated with pozzolanic
agents prior to disposal.
In Alternative 8, excavated soils would be mixed with pozzolanic agents in a pug mill prior to disposal
The addition of pozzolanic agents will tend to solidify contaminated soils and may reduce contaminant
mobility. If this alternative is chosen, treatability studies would be conducted to determine if these soils
are amenable to pozzolanic f1X3tion, and if pozzolanic f1X3tion will adequately reduce contaminant
mobility. Environmental monitoring would be continued at predetermined intervals. The volume of
material to be disposed would increase approximately 50 percent from 640,000 cubic yards to
960,000 cubic yards as a result of pozzolanic treatment.
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8 COMPARATIVE ANALYSIS OF ALTERNATIVES
A comparative analysis of alternatives using each of the nine evaluation criteria. as required by federal
regulation, is presented in this section. The purpose of this analysis is to identify the advantages and
disadvantages of each alternative relative to the other alternatives. A separate evaluation of the alterna-
tives is presented under the heading of each criterion.
8.1 PROTECTION OF HUMAN HEALTH AND ENVIRONMENT
Protection of human health and the environment is addressed to varying degrees by the five proposed
alternatives. Alternative 1 is the No Action Alternative. As proposed. it would have no effect on the
site; therefore, it does not address any of the identified concerns. Indeed, an increase in blood lead
concentrations over time could occur.
Alternative 3, 6, and 8 provide protection of human health through installation of a soil and sod barrier
betWeen residents and underlying contaminated materials. All. three address the concerns of exposure
through direct contact with soil contaminants or tracking contaminated residential soil into homes as a
source of house dust. Alternative 5 addresses these concerns, but to a lesser extent than the others
because of the requirement for rigorous maintenance. All alternatives address the exposure pathway of
local garden produce.
None of the alternatives would alter the toxicity or persistence of the soil cOntaminants. Alternative 8
does include a treatment plan for excavated soils that would solidify the soils once they are ~emoved
from the site and may reduce mobility.
In general, permanence of remedial actions is greatest for Alternative 6 with its essentially complete
removal of contaminated soils. Alternatives 3 and 8 provide a degree of permanence through removal of
surficial layers of contaminants, requiring less implementation time and efron, but they rely on a greater
need for institutional controls. Alternative 5 provides the least amount of protection on a permanent
level because of its reliance on institutional controls and the susceptibility of the sod layer to withstand
normal human activities and inconsistencies in maintenance.
8.2 COMPLIANCE WITH APPLICABLE OR RELEVANT AND
APPROPRIATE REQUIREMENTS (ARARs)
With the exception of Alternative 1, the No Action Alternative, all alternatives meet federal and State of
Idaho ARARs. A funher discussion of compliance with federal and state ARARs is included in
Chapter 10.
8.3 LONG-TERM EFFECITVENESS
The residual risk (the risk remaining after implementation) increases from lowest to highest in the fol-
lowing order of alternatives: 6,3 and 8, 5, and 1 (No Action Alternative). Alternative 6 would result in
the least amount of residual risk because of the volume of contaminated soils that would be removed to
ensure that future exposure to onsite residential soil sources does not occur. Although Alternatives 3
and 8 do not reduce residual risk to the same level as Alternative 6, they would protect the communities
in the long term if institutional control measures were implemented and followed. Alternative 5 pro-
vides the least long-term protection sinl:e the sod barrier may be easily breached.
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Maintenance requirements for all alternatives would be fairly similar. Each alternative incorporates a
sod or grass cover and similar institutional controls. However, the level of the requirement varies with
the alternative. Alternative 5 is more sensitive to maintenance requirements because a layer of sod .
the only barrier betWeen residents and the underlying contaminated soils. Alternatives 3 and 8 follow
with a layer of clean fill of at least 12 inches under the sod layer. Alternative 6 requires the least
amount of maintenance as a result of the eXtensive layer of fill (up to 7 feet) needed to return residen-
tial yards to their original grade.
Environmental monitoring would vary according to the degree of protectiveness incorporated within the
remedial alternatives. Alternative 5 would require the greatest amount of monitoring to ensure that the
sod barrier remains effective. This would entail frequent soil and litter metals analyses and blood lead
analyses. Alternatives 3 and 8 would require periodic monitoring of the surficial soil layer to check for
airborne recontamination and periodic monitoring of the remediated soil profile to check for disruption
and recontamination of the soil barrier. Alternatives 3 and 8 would also require periodic blood lead
analyses. Alternative 6 would require periodic monitoring of the surficial soil layer and periodic blood
lead analyses. Alternative 1 would include environmental monitoring to check for changes in contami-
nant levels with time. Blood lead screening would be discontinued when warranted.
The disposal recommendation for residential soil is consistent for all alternatives except for
Alternative 8, which includes the addition of pozzolanic agents prior to disposal. The long-term
effectiveness of the disposal recommendation is ensured through appropriate closure requirements and
management by institutional controls.
8.4 REDUCTION OF TOXICIlY, l\'IOBILITY,
VOLIDIE, Al'ID PERSISTENCE THROUGH TREATMENT
81ch alternative, with the exception of the No Action Alternative, requires varying degrees of contam
nated soil removal and placement of a "clean" fill cover to create a barrier betWeen underlying soil con-
taminants and the residential population. Alternative 8 is the only alternative to incorporate treatment
as pan of the remedial action. This treatment would solidify the exClvated soil and would likely reduce
the metals mobility from soils at the disposal area. The additional decrease in mobility by pozzolanic
treatment is not known.
All alternatives would increase volume of soil remaining within the Superfund boundaries through bulk-
ing (10 to 15 percent of the in-place volume). The volume would increase by approximately 50 percent
as a result of the pozzolanic tre:ltment in Alternative 8 as compared to Alternative 3. None of the alter-
natives proposes to change the toxicity or persistence of the contaminants.
8.5 SHORT-TERl\'1 EFFECTIVENESS
Most of the remedial actions are similar in the technologies proposed for implementation. The extent
of the remedial action varies considerably among alternatives. Alternatives 3, 5, and 8 are generally
equivalent in the amount of shon-term risk they pose to the community. Each requires the removal of
the top vegetative layer and varying amounts of underlying soil. Each alternative would include continu-
ing to prioritize residential yards on the basis of sensitive subpopulations. Completion of these alterna-
tives would require 4 to 6 years. Alternative 6 would require considerably more time to complete
because of its. soil removal requirements. E:cposure to fugitive dust generated by the remedial activities
is the common risk shared by each alternative. Localized releases of metals-laden dust would likely
occur during excavation, but such releases would be minimized by dust control techniques. However,
none of the action alternatives is expected to substantially affect the communities during remediation.
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Alternative 6 would create a slightly higher risk to workers and residents than the other alternatives,
mainly because of the volumes of materials to be excavated and moved and the duration of time/needed
to accomplish Alternative 6. The greater excavation volume would be associated with increased noise
and greater annoyance of residents from more construction activity. Heavy equipment traffic would also
increase on local roads with implementation of Alternative 6. .
Construction contractors would need protection against dermal and respiratory exposure to the dust
while working in contaminated areas. Protective clothing and respirators or dust masks would help
control this risk. These risks are inherent to all alternatives.
8.6 Il\1PLEMENTABILITY, RELIABILITY, AND CONSTRUCTIBILITY
In general, there is not a great difference among alternatives in the types of remedial activities
proposed. The extent or degree to which the remediation is applied does vary significantly betWeen
alternatives. Most of the activities proposed as part of the alternatives including disposal are
well-developed technologies. All of these activities are technically feasible, but the level of effort
associated with each is different.
Alternative 5 is the most easily implemented alternative proposed, requiring only the removal and
replacement of a sod and grass layer. However, Alternative 5 was judged to be the least reliable because
of l
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I Table 8-1
Summary or Estimated Costs
I Annual
I
Operations &
Alternative Capital Cost Maintenance Cost Present Worth Cost
Alternative 3
12.inch removaU S 34,200.000 ~.OOO S 41.300,000
replacement
Alternative 5
Sod layer removaU 14.400,000 792.000 28.600.000
replacement
Alternative 6
Deep excavation! 189,000,000 257,000 193.000.000
replacement
Alternative 8
12.incl1 removaU ~.900,000 460,000 56,000,000
replacement and
pozzolanic treatment
8.8 STATE ACCEPTANCE
This decision document presents the remedial actipn selected by the U.S. EP A and IDHW for th
Populated Areas Residential Soils Operable Unit at the Bunker Hill Mining and Metallurgical Complex
Site in nonhern Idaho.
8.9 COl'tTh'IUNITI ACCEPTANCE
U.S. EP A and IDHW solicited input from the community on the cleanup methods proposed for residen-
tial soils. Public comments, in general. indicated suppon for the recommendation of Alternative 3 in
the proposed plan and urged an expeditious implementation of the plan. Public comments are specifi-
cally addressed in the Responsiveness Summary section of this document and some have been incor-
porated into the selected remedy.
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9 THE SELECTED REl\1EDY
9.1 INTRODUCTION
IDHW and U.S. EP A have selected Alternative 3 (as modified by public commentS) as the remedy for
contaminated residential soils at the Bunker Hill site. This selection is based on the Administrative
Record for the site. This remedy addresses surficial residential soils only in currently established resi-
dential areas. Because of the extent of contamination, both areal and at-depth, this remedy does not
focus on complete removal of contamination from residential yards, but focuses on creating a barrier
between contaminantS and residentS. The remedy employs both engineering and institutional controls to
create and maintain the barrier.
9.2 RESIDENTIAL SOILS REMEDY
This remedy is made up of the following componentS:
SOIL SAMPUNG
Approximately 60 percent of residential properties have been sampled at the 0- to I-inch interval. Prior
to commencement of remedial action on a specific yard. sampling will be required at the 0- to 1-, 1- to
6-, 6- to 12-, and 12- to IS-inch intervals. The sampling will be conducted in accordance with estab-
lished sampling procedures for this site including analysis of soil passing an 8O-mesh screen for determi-
nation of the 1,000 ppm threshold leveL
REMOV AUREPIACEMENT OF SOn.s
The removal of contaminated soil and sod and consequent replacement with compacted clean material
will be conducted as follows:
If the (). to I-inch or 1- to 6-inch-depth intervals exceed the threshold level, 6 inches of contam-
inated material will be excavated and replaced. In addition, if the 6- to 12-inch interval exceeds
the threshold level, another 6 inches (total of 12 inches) will be removed and replaced. If the
6- to 12-inch interval does not exceed the threshold level, the property will have a 6-inch
excavation and replacemenL
In the case where the 6- to 12-inch-depth interval exceeds the threshold level but the 0- to
I-inch and 1- to 6-inch intervals do not, 12 inches of material will be excavated and replaced.
If the 0- to I-inch and the 1- to 6-inch and the 6- to 12-inch intervals do not exceed the
threshold level, the property will not be remediated.
All produce garden areas in every yard will receive 24 inches of clean materiaL Oean soil for produce
gardens will be made available to residentS whose yards do not require remediation.
If existing property grades permit, it is possible that no excavation of residential soils would be necessary
and the cover material could be placed and revegetated without exceeding the height of the foundation.
However, it is more likely that some cut and removal of existing soil will be required to properly accom-
modate the clean cover and new sod.
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For each residential yard. the ex:1ct nature of the remediation (i.e., how much sod to replace, which
bushes to remove, ete.) would have [0 be considered on a case-by-c1Se basis. However, for consistency,
the following areas would generally be remediated within each yard:
.
Sad areas
.
Roadway shoulders (if curb and gutter are not present) to asphalt or pavement and to
the lateral extension of property lines
.
Alleys (if unpaved) to [he extension of the lot lines
.
Landscaped areas
.
Garden areas
.
C'npaved driveways
.
Garages with din noors
.
Srorage areas
Are3S immediately associated with the residential properties (i.e., road shoulders and alleys) will not
require top soil, but will require replacement will clean material in kind or a permanent cover. Any
steep hillside are3S located immediately adjacent to yards and with a soil lead concentration greater than
the threshold level will be stabilized as part of this action to prevent runoff and recontamination. The
final remedy for the hillsides will be addressed in a subsequent ROD.
Based on dose response modeling, a threshold level of 1.000 ppm lead in residential soil was determin
to be the threshold cleanup level most appropriate for this site. The results of the threshold assessmen ,
and the assumptions used, are summarized in Table 9-1.
Requirements for removal and replacement of soils on areas adjacent to residential lots, such as vacant
residential lots, within the Populated Are3S will be the same as for occupied properties.
VISUAL MARKER
For residential yards that require exc:lvation to 12 inches, if the results of sampling in the 12- to 18-inch
interval exceed the threshold level, a visual marker (such as erosion control fabric or other suitable
material) will be placed prior to backfilling with clean fill.
REVEGETATION
During the excavation process, all existing sod and soil coverings will be removed and disposed of along
with the soil. Larger trees and shrubs will be left in place but subject to pruning. After spreading, com-
paction, and grading, clean fill will be revegetated. The lawn areas of remediated yards will generally be
revegetated with sod. Steep hillsides and other remediated are3S not currently planted with lawns (such
as vacant lots) will be stabilized and hydroseeded with native grasses. If preferred by a property owner,
hydroseeding with native grasses could be substituted for the sod. Vacant lots will be hydroseeded with
native grasses after remediation. To the extent practicable, all yard landscaping will be returned to its
original condition.
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t
"
Tllble 9.1
Risk Rllni:e ror . Threshold Level or 1,000 ppm
POIOI Remedlllllon Predicted Mun 'JI, or Children Predlcied 10 Exceed
1,000 ppm Y IIrd Soli lIouw DIISI Blood Lelld Level ~dl
Threshold No. or lIomn
Sunul"s Remedlilled Pb Cone ppm Pb Cone ppm I.) yn 1.10 yn 10 ..~dl 15 ~dl 25 ~dl
Kellogg 1 958 121 1,450 7.5 7.0 15-24 2-7.8 < 1-1.0
2 958 . 121 121 2.8 2.7 < 1-1.6 <1 <1
3 958 121 143 2.9 2.8 < 1-1.6 <1 <1
Smellervllle 1 238 122 1,203 6.6 6.1 9-18 1.3-5.1 <1
2 238 122 122 2.8 2.7 <1-1.e> <1 1,000 ppm lead replaced with lOils of 100 pprn Pb.
House Dust ConcenlrationnAs observed in 1988.
Indoor.Ouldoor Panition--70%:JO%.
2. Yard Soil ConcentrationnAiI yards with levels of > 1,000 ppm lead replaced wilb wils of 100 ppm Pb.
House Dust ConcenlralionnEquallo soil concentration on individual bome basis.
Indoor.Outdoor Panition--70%:JO%.
3. Yard Soil Concenlration--All yards with levels of 1,000 pprn lead replaced with soils of 100 ppm Pb.
House Dust ConcenlralionnEquallo community mean yard soillevcl at rcmediated horna, equal 10 yard soil at nonremedialed homa.
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DUST SUPPRESSION
Dust suppression measures will be implemented throughout the remediation process to reduce exposur
of workers and residents to airborne contaminants. Dust suppression will include, but not be limited to
.
Watering of residential yard areas prior to exClvation activities
.
Continued weltering during excavation, as necessary
.
Placement of tarps or covers over exClvated materials
.
Use of tarps or covers over truck beds to reduce blowing dust and spillage during trans-
portation to the \1I3Ste repository
.
Daily cle~lnup of 311 spilled or tracked soils from sidewalks, roadways, etc.
DISPOSAL OF CONTAMr.-lATED ~L\TERL\LS
The analysis of AppliClble or Relevant and Appropriate Requirements associated with the disposal of
contaminated residential soils assumed that the soils repository would be 10Clted within the Bunker Hill
site. It is recommended that Page Ponds be used for the disposal repository beCluse it has adequate
volume, is within the Bunker Hill site, and the action will reduce the contaminated windblown dust
originating from the Page Ponds area..
The use of Page Ponds as the repository will require that it be Clpped to minimize airborne contaminant
migration and reduce the threat of direct contact exposure. The cap surface area will be compacted ana
graded to prevent ponding and minimize infiltration: it will also be vegetated for stabilization and
moisture absorption. Access to the area will be restricted by fencing, locked gates, and warning si
Future use of the repository will be limited and subject to institutional controls.
If Page Ponds is not used as the residential soil repository, the chosen repository site will be subject to
agency evaluation and public notification.
INSTITUTIONAL CONTROU)
The goal of the institutional controls program is to develop a flexible system that builds on existing
administrative structures and programs rather than create a new layer of bureaucracy. Institutional con-
trols regulation will be uniform throughout the Bunker Hill site, irrespective of jurisdictional bound-
aries. The institutional controls associated with this ROD are designed for the maintenance of residen-
tial soil barriers onty. These controls are necessary and are an integral pan of the selected remedy.
Physical ~ram Requirements
Planning, Zoning, Subdivision and Building Permit Regulations: Implementation of planning, zoning,
and subdivision controls through local ordinances, designed to protect and maintain barriers when devel-
opment or any action that would breach a barrier takes place.
Disposal or Unearthed Contaminants: When a barrier is broken, contaminated soils that are removed
must be handled to minimize exposure, collected for disposal, and transported to a proper disposal site.
A means for disposal of incidental contaminated soils will be provided to residents.
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Provision or Clean Soil: A program will be implemented to provide a centrally located supply of clean
replacement soil (both fill and topsoil) to facilitate barrier repair, maintenance, and establishment of
produce garden areas.
Administrative Program Requirements
Coordination or Public Institutions: Effective administration of a uniform Institutional Controls
Program will require shared authority and resources. The four cities and Shoshone County will play an
important role through already established permitting procedures. It has been recommended that the
Panhandle Health District will administer the effort with permitting, inspection, records maintenance,
and enactment of regulations, where necessary, across jurisdictional boundaries.
Deed Notices: These are a method to notify new owners of their barrier system and their responsibility
for participation in that system.
Educational Programs: Educational programs will be developed to keep information about the barrier
system in the public eye and to help the public recognize when disruption of the barrier systems requires
attention or caution. Distribution of information should be provided through pamphleting, brochures,
and general media exposure.
Permitting and Inspection Procedures: Permit issuance and record keeping procedures should be
tailored to minimize inconvenience to permit applicants. A permit system that integrates with existing
permit routines will be implemented.
Monitoring and Health Surveillance Programs: Monitoring will be required to assure both program
performance and effectiveness. Health intervention effortS will be required to document and assess suc-
cess in achieving remedial goals and objectives.
An Evaluation of Institutional Controls for the Populated Areas of the Bunker Hill Superfund Sile outlines
the various options associated with each of the institutional control requirements and will be used in the
remedial design phase to guide implementation of the program. The implementation phase, referred to
as Phase II, will include passing local ordinances, setting up an administrative system to oversee and run
the program, and documentation of detailed procedures for each of the program components.
MONITORING
The effectiveness of the institutional controls program will be evaluated periodically. Appropriate air
monitoring will be conducted to identify the occurrence of contaminant migration during remedial
activities. Any exceedances of the standards will result in immediate implementation of additional dust
suppression measures or a shutdown of construction activities.
Since contaminated material will be left onsite, both in Populated and Non-populated Areas, ongoing
monitoring of fugitive dust and residential yards is necessary to ensure that the clean barrier is
maintained.
9.3 CHANGES TO PROPOSED PLAN
During the public comment period, several issues were raised concerning the preferred alternative in the
Proposed Plan; consequently, several minor modifications have been incorporated into the selected
remedy in response to those concerns. The following is a list of those modifications:
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.
Depth of excavation may be variable (less than 12 inches) depending on depth of
contamination.
.
For those properties requiring a visual marker, it will be a material that can be easily
seen during digging or excavation aCtivities. The visual marker does not !lave to be a
2-inch gravel layer.
.
RequirementS for disposal site closure included an impermeable cap to protect ground-
water. ARARs associated with groundwater and surface water protection will be
addressed in a subsequent FS and ROD.
.
The scope of the institutional controls program will be reevaluated periodically because
the requirementS of a program of this nature may change with time.
.
Soil will be provided for homeowners who have a soil lead level less than 1.000 but who
want a garden.
9.4 COST
Cost evaluations. including the assumptions used, are presented in the Feasibility Study. A summary of
the capital costS associated with the selected alternative is shown in Table 9-2. The costS are order-of-
magnitude (+50 percent to .30 percent) estimates. Capital costS are those required to initiate and con-
struct the remedial aCtion. Typical C3pital costS include construCtion equipment, labor and materials
e:xpenditures. engineering, and construCtion managemenL Bid and saJpe contingencies are also included
in the total capital COSL Projected Jnnual operation and maintenance costS for the selected remedy are
also presented in Table 9-2. These costS are necessa.ry to ensure the continued effectiveness of a
remedial aCtion.. Included are such items as labor and materials: monitoring and the institutional con
trois program; and insurance. taxes. ete.
The feasibility level cost estimates shown have been prepared for guidance in project evaluation and
implementation from the information available at the time of the estimate. The final costS of the
project will depend on aCtual labor and material costS. actual site conditions. productivity, competitive
market conditions. final project scope and schedule. and other variable faCtors. As a result, the final
project costS will vary from the estimates presented here.
Present wonh costS are calculated using a 5 percent discount rate and a 3O-year estimated project life.
The present wonh cost for the selected remedy is S40.6 million (Table 9-2). Capital costS and long-term
annual operations and maintenance (O&M) costS are included in the total present wonh COSL Long-
term O&M costS are those associated with maintaining an alternative after implementa~on is complete.
CostS presented in Table 9-2 are lower than those presented in the Residential Soil Feasibility Study or
the Proposed Plan. The reduction in cost is associated with changes to the Proposed Plan as presented
in Section 9.3. SpecifiC311y, removing the requirement for an impermeable cap accountS for the cost
reduction.
9.5 PERFORJ.\IANCE REQUIREl\'IENTS
A remedial aCtion objective for this operable unit is to decrease the exposure to lead-contaminated
residential soils such that 95 percent or more of the children in the area have blood lead levels below
10 ,l.Lg/dl and that less than 1 percent have blood leads greater than 15 ,l.Lg/dl. The former is projeCted to
be achieved by reducing the overall soil and dust loading concentration to 700 to 1.200 ppm. Th
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Table 9-2
Summary or Estimated Costs ror Selected Remedy
Capital Cost Annual O&M Cost
Item .($) ($)
Occupied Lots Remediation Total 18,502,000 0
Vacant Lots Remediation Total 3,665,223 0
Disposal Cap 599,078 0
Operations and Maintenance 0 400,209
Health and Safety (10%) 2,276,630 0
Division 1 Costs (8%) 1.821,304 0
Engineering Services (10%) 2,276.630 0
Subtotal 29.140.865 400,209
15% Contingency 4,371.130 60.031
Total Capital Cost 33,500.000 460.000
Total O&M Present Worth 7.100.000
Total Present Worth 40.600.000
Notes:
1. Division 1 costs include the costs for general conditions. mobilization, permits, bond. and
insurance.
2. The "Occupied Lots Remediation Total" is based on remediation of 1,273 residences.
3. The "Vacant Lots Remediation Total" is based on remediation of 268 vacant residential lots.
4. The present worth was calculated using a discount rate of 5% for 30 years, then rounded to
three significant figures.
5. Institutional control costs include personnel, benefits, contractual services, supplies and
materials, capital equipment, health intervention program, soil collection program, and
material supply program required for annual maintenance of remedial actions.
6. The disposal cap was assumed to be a I-foot soil cap.
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1.000 ppm yard soil threshold cleanup level will reduce mean yard soil concentrations to approximately
200 to 300 ppm in residential areas. In combination with other remedial measures and the positive
effeCtS likely to be seen in other media. it is expected that this objective will be met. Achieving t
latter objective of less. than 1 percent of area children with blood lead concentrations below 15 \.1g/dl
less dependent on the mean soiUdust concentrations than on the soil concentration left in an
unremediated yard. A child living on an unremediated yard of 1,000 ppm is estimated to have a 0.1 to
2.5 percent (depending on various assumptions) chance of exceeding 15 \.1g/dl blood lead in the Bunker
Hill post-remediation environment. Any higher threshold cleanup level would result in unacceptable
risk to that child. It is expected that this goal will be achieved by replacing all residential yards with a
lead concentration greater than 1,000 ppm lead with clean material (less than 100 ppm). This
expectation assumes that fugitive dust sources will be controlled and house dust concentrations will con-
sequently decrease and that remediated yards will not be recontaminated.
This remedy mitigates the risks assodated with the following pathways identified in the risk assessment:
.
InhalationJlngestion of Contaminated Residential Soil
Ingestion of Locally Grown Produce
.
This remedy does not directly address the risks assodated with the following pathways identified in the
risk assessment:
.
Consumption of Contaminated Groundwater
InhalationJ1ngestion of Windblown Dust
InhalationlTngestion of Contaminated House Dust
.
.
Actions are being taken now to address these risks. The final remediation with respect to these risks
will be addressed in J subsequent feasibility study.
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10
STATUTORY DETERMINATIONS
The selected remedy for residential soils is protective of human health and the environment, will comply
with federal and state requirements that are legally applicable or relevant and appropriate, and is cost-
effective. The selected remedy does utilize alternative treatment and resource recovery technologies to
the maximum extent practicable. However, since no treatment and resource recovery technologies were
found to be practicable, none were incorporated into the remedy. Because this remedy will result in
hazardous substances remaining onsite above health-based levels, the 5-year review provisions of
CERCLA Section 121c will apply to this action. The following sections discuss how the selected remedy
meets the statutory requirements.
10.1 PROTECTION OF HUl\'lAN HEALTH AND THE ENVIRONMENT
Lead absorption among young children is the most significant health risk posed by this site. Residential
soils were identified in the RADER to be one of the primary contributors to risk associated with sub-
chronic lead absorption. In order to reduce blood lead exposures, the selected remedy replaces metal-
contaminated residential soils with uncontaminated soil, thereby breaking the exposure pathway betWeen
soils and children. Post-remediation modeling scenarios show that the soil cleanup level of 1,000 ppm
will result in a sitewide mean blood lead level of 2.7 to 3.9 p.g/dl. Only 1 to 3 percent of the children
living onsite are predicted to have blood lead levels in excess of 15 p.g/dl. It is expected that at least
95 percent will have a blood lead level less than 10 l-1g/dl.
Inclusion of produce garden area remediation to a depth of 24 inches will also reduce the exposure to
cadmium, lead, and zinc associated with consumption of local garden produce.
The remedy selection will also effectively mitigate chronic noncarcinogenic risks associated with inges-
tion of antimony, cadmium, and mercury via soil ingestion. Carcinogenic risks associated with arsenic
and cadmium exposure through fugitive dust will be addressed under a separate operable unit.
Contaminated residential soils will be consolidated in a permanent repository. All consolidation areas
will be protected from erosion and surface infiltration by a revegetated topsoil cap and contouring.
Experience with residential soil removal actions during 1989 and 1990 indicate that with appropriate
precautions there will be no unaa:eptable short-term risks or cross-media impacts associated with the
implementation of the selected remedy.
The institutional controls program will ensure the maintenance of physical and institutional barriers that
protect against metal exposure. Continued blood lead and residential soils monitoring will measure the
long-term success of the selected remedy.
House dust has also been identified as a significant lead exposure pathway. Residential soils are a con-
taminant source to house dust. Thus, remediating residential soils will reduce a contamination pathway
to home interiors. Fugitive dust will need to be controlled and monitored concomitant with residential
soil remediation to minimize soil recontamination. The RADER discusses the rate of soil recontamina-
tion from airborne fugitive dust and recommends that airborne dust be reduced substantially. Control of
fugitive dust will also eliminate direct exposure to highly concentrated dusts, reduce accumulation of
metals in homes, and prevent excessive deposition on homegrown produce in local gardens. Dust
control measures have been taken on the site in the past 2 years. These measures include irrigation of
the Central Impoundment Area (CIA), revegetation of some of the Bureau of Land Management (BLM)
property on Smelterville Flats, placement of large rocks on barren areas north of the Kellogg Middle
School, and spreading of sawdust on the Smelterville Flats area. Control of fugitive dust from barren
hillsides is being addressed in the hillside revegetation order previously discussed. Additional dust
-------
control measures will be implemented by the potentially responsible parties (PRPs) under the July 1991
Administrative Order on Consent (see Section 2.5).
The analysis presented in the RADER and the FS shows that the remedy selected for residential soil~
w1l1 break the significlDt exposure path'W'a)'S associated with soil. Once residential soil removal is com-
pleted, waste soils will be consolidated within the area of contamination of the Bunker Hill site, and an
institutional controls program is implemented, risks associated with metal-rontaminated residential soils
will be mitigated. Therefore, IDHW and U.S. EP A have concluded that the selected remedy for residen-
tial soils will be protective of public health and the environmenL
10.2 COiYIPLIA1'ICE \VITH APPLICABLE OR RELEVANT
A..'ffi APPROPRL\TE REQUIREl\'rENTS (ARARs)
Pursuant to SARA Section 121(d), remedial actions shall attain a degree of cleanup of hazardous sub-
stances, pollutantS. and contaminantS released into the environment and control of further release which.
at a minimum. assures protection of human health and the environmenL In addition, remedial actions
shall, upon their completion, reach a level or standard of control for such hazardous substances,
pollutantS, or contaminantS which at least attains legally applicable or relevant and appropriate federal
standards, requirementS, criteria, or limitations, or any promulgated standards, requirementS, criteria, or
limitations under a state environmental or facility siting law that is more stringent than any federal
standard (ARARs). All ARARs would be met by the selected remedy.
The federal and state ARARs identified by U.S. EP A and IDHW, respectively, for residential soil
removal are presented in Tables 10-1 through 1~. An evaluation of chemical, location, and action-
specific ARARs is presented in Section 2 of the Residential Soils Focused Feasibility Study. Additional
discussion of chemical-specific ARARs and other requirementS to be considered (TBCs) is presented in
Section 3 of the RADER.
There are currently no promulgated laws or standards for lead in soil. However, a site.specific threshold
level of 1.000 ppm lead in residential soil. that is expected to result in a community average of 200 to
300 ppm, has been developed for protection of human health.
For the Bunker Hill residential SQils action, contaminated residential soil will be consolidated from yards
throughout the site into a single location. Since some residential soils did demonstrate RCRA hazard.
ous characteristics for lead and pesticides (chlordane), an analysis of the applicability or relevance and
appropriateness of the RCRA hazardous waste regulations is required:
For RCRA to be applicable, the material must demonstrate hazardous characteristics, and the
proposed action must involve either treatment. storage, or disposal of the material as defined by
RCRA. As the Remedial Investigation 5ampling and analysis has shown, residential, propenies
and all other areas within the Bunker Hill Superfund Site are contaminated to various degrees
with lead and other heavy metals. Contamination is contiguous throughout the site and the site
is considered a single 'area of contamination' (AOq. As described in the preamble to the final
NCP. movement of wastes and soil within an AOC at a Superfund site does not constitute dis-
posal or 'placement' and therefore does not trigger RCRA, Subtitle C, disposal requirementS.
For this action, all soil consolidation and movement will be within a single AOC; thus, the
RCRA requirementS are not applicable.
For RCRA to be relevant and appropriate, the RCRA requirements must address problems or
situations that are similar to the action being taken and the requirementS must be well suited to
the site. U.S. EP A has determined that portions of the RCRA closure requirementS are
relevant and appropriate for this action.
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_.
f"
It..
[
I.
1
(
1
Table 1().1 (Pap 1 of 2)
Federal CbemlcaJ-Spec1l1c ARARa
CbemJcaJ-Spec1l1c Citation Prerequisite Requ1remeDt
LAir
A. Applicable Requirement
1. Ocaa Air Act
NauooaJ Ambient 42 U.S.c. Section 7401 et Establisbes ambient air quality Emissions of paniculates and
Air Quality ~; 40 CFR Pan SO - standards Cor emissions of cbemicals which occur during
SWldarda (NAAQS) chemicals and paniculate remedial activities will meet
mauer. tbe applicable NAAQS which
are as follows.
Particulate Mauer. 150 JJ.g/m3
24-hour average cona:ntration,
50 JJ.g/m3 annual arithmetic
mean.
Lead: 1.5 /J.g Pb/m3 (.5 JJ.g
Pb/m3 is proposed)
B. Relevant and None
Appropriate
Requirement
C. To Be Considered None
Materials
II. Soil and Dust
A. Applicable Requirements None
B. Relevant and None
Appropriate
Requirement
C. To Be Considered
Matcrlals
1. Rist Asacslment Tec:bnicaJ Enfora:ment Evaluates baseline bealtb risJt The ARA1U for soils may not
Data Evaluation Contr2d WOlt due to current site exposures provide adequate protection to
Rcpon (RADER) Assicnment ClOOO2 and establishes contaminant human bealth; thereCore a risk
for the Populated Prepared by: Jacobi levels in environmental media at asscsament approacb using
Areal of the Bunker Engineering Group, lne:. the site Cor the protection of these guidances should be used
Hill Superfund Site and TcrraGrapbic:s. lne:. public health. in determining c:leanup levels.
2. SoillDust Lead Centers Cor Disease Removal of contaminated soils. Lead in soiVdust appean to be
Contamination Control's statement on n:sponsible for blood lead
Advisory childhood blood lead levels in cbildren increasing
levels, 1985. above background levels when
the c:ona:ntrations in the
soiVdust exceed 500-1,000
ppm. This cona:ntration is
based upon the established
CDC blood lead level oC 2S JJ.g
Pb/dl in children. When
soiVdust lead concentrations
exc:ced 500-1.000 ppm, blood
lead levels in children are
-------
Table lG-l (Pac- 1 0(1)
Fedcnd CbcmJcaJ.SpccUk ARAR.s
CbemkaJ-S pccUk CllaUoD Pruequlsila R.cqulremeDt
3. EP A ll11erim Office of SoIiI1 Waste anl1 Esc.ablisbcs an interim soil This cuil1aDce al10pta !be
Guidance Emergency Rcspon.se cicaJ1up lcvd Cor lOW lead in l'ea)m-menl1atioD coDta.iDcd iD
Cooccn1inI Soil (OSWER) Directive n::sidentiai settinp. the 1985 CDC statement OD
Lead Oc:anup ~S.4-02. September childhood lead poisoDinS (aD
I....cYda al S u perfuod 1989. interim soil c1eaoup level Cor
SitCI residential settinp of 500..
1,000 ppm lOW lead). and is 10
be Collowed when the c:um:nl
or predicted IaDd use of
. coDt.1minatcd are:tS is
n::sidentiaJ.
4. EP A Stnt~ fOC' Eavironment.11 Protection Prcscnta a str.negy 10 reduce The stntegy was I1cvelopcd 10
ReducinC Lead Agency I ad expos un:. part icu!arty to reduce lod exposures to the
~ October 3, 1990 yoU"C children. p-ea test c:xten t possible. Goala
of the stntegy an: to:
1) significantly reduce blood
lead incidence aboYc 10 141
Pbldl iD children; and
2) reduce tbe Imounl of lead
introduced into the
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I Table 10.1 (page 1 of 1) I
Federal LocaUon-Speclfic ARARs
lAcaUon-Speclfic Citation Prerequisite Requirement
L Federal
A Applicable Requirement
1. Historic project National Historic: Property within the residential The remedial action will be
owned oc controlled Presesvation Act; areal of the site is included in or designed to minimize tbe effect on
by a Federal 16 U.s.c. 470 et eligible Cor tbe National Register historic oropenies and historic
Agency seq.; 40 CFR - of Historic Places. landmarks.
b3bl(b); 36 CFR
Part 800.
2. Site within an area Archeological and Property within the residential The remedial action will be
wben: action may Historic Preservation area of the site contains historical designed to minimize the effect on
cause ilTeparable Act; 16 U.S.c. 469; and archeological daLa. historical and archeological daLa.
harm, Iou, or 40 CFR 6.301(c).
desllUction of
artifacts.
3. Site located in area Endangered Species Determination of presence of The remedial action will be
of aitical habitat Act of 1973; endangered or threatened species. designed to conserve endangered
upon whicb 16 U.S.c. 1531.1543; or threatened species and their
endangered or 50 CFR Parts 17, habitat, including consultation witb
threatened species 401; 40. CFR the Depanment of Interior if such
depend. 6.302(b). areas are affected.
4. Site located within a Protection of Remedial action will take place The remedial action will be
floodplain. Flood plains, within a l00-year Ooodplain. designed to avoid adversely
Executive Order impacting the Ooodplain wherever
11988; 40 CFR 6, possible to ensure that the action's
Appendix A planning and budget reOecta
consideration of the Oood hazarda
and floodplain management.
S. Wetlands located in Protection of Remedial actions may affect The remedial action will be
and around the site. Wellands; Executive wetlands. designed to avoid adversely
Order 11990; impacting wetlands wherever
40 CFR 6, Appendix possible, including minimizing
A wetlands desllUction and preserving
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Tab!. 1()'1 (Page 1 oC 1)
Federal LocaUonoSpectnc ARAR.s
LocaUoo.s pecil1c CILaUon PrerequisHa Requirement
6. Waten in and Con Watc:1" Act Capping, dike SLabiJizatiol1, The Cour conditions that must be
around the site. (Section 4(4)- coD.SU'Uction of berms and levees, sati.sfied before dredge and fill is
Dredge or Fill and disposal of contaminated soil. an aUowable altc:ruative are:
Requirements; 33 waste matc:rial or dredged
U.s.c. 1251-1376; material are examples of activities . There must be no
40 CFR 2:30. :::31. that may involve a discharge of pr.acUc:al alternative.
dredged or flU materiaL
. Discharge of dredged or
fill materia! must not
C3USC a violation of Sl.1te
water quality sLandards.
violate any applic:able
toxic effiuent sLandards.
jeopardize thfCILCned or
endangered species. or
injure a marine sanctuary.
- No discharge snaU be
permitted that wiU C3USC
or contribute to
silP\ilic:ant devadation of
the water.
. Appropriate steps to
minimize adverse eCrecu
mUll be Laken.
Determine long- and shon-term
effects on physic:al. chemic:al. and
biological components of the
aquatic ecosystem.
7. Area (X)Quining rJJb FLSb aDd WildliI.e Activity affecting wildlife and Remedial action will consave and
aDd wiJdlile babi~L Conservauon Act of aon-pmc rLSb. promOte conservation of non-game
1980; 16 U.s.c. ash and wildlife and their habiuts.
2901; 50 CFR
Pan 8J.
s.. l00.yar f1oodpl.1.iJl. lDcaUoG SLand.a.rd RCRA b.u.udOUI waste Facility located in a tOO-year
roc Hazardoua Wute IfCItmcnt stor.age and disposal Ooodplain must be designed.
Flcilitia - RCRA; consuuc:ted, oper.ated. and
42 U.s.c. 6901; 40 mainuined to prevent washout of
CFR 264.l8(b). any lOO-year Ooodplain.
B- Relevant aDd NODe
Appropriate
Requirement
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I Table 10.3 (Page 1 or 4) I
Federal A.ctlOD-Spec1J1c: ARARs
A.c tJOD-S pec1J1c: CllatJOD Prereqllislle RequlremeDI
A. Applicable Rcqui~ment
1. Dispoul of Solid RCRA 42 U.s.c. ~6901 Maintenance of a facility at . Facility or pra<:tices in floodplaina will
Waste ct scq.; 40 CFR 257 which solid wastes ~ nol restrict flow oC basic flood, ~uce
disposed oc. the tcmpor.uy water storage capacity
of the floodplain or othcrwi.sc result in
a wasb-out oC solid waste.
. Facility or practices shall not cause or
contribute to talUng oC any endangered
or threatened species.
. Facility or practices shall not result in
the destruction or abuse oC critial
habitaL
. Facility or practice shall not cause
discharge oC pollutants into waters oC
the U.s. in violation oC a NPDES
pcrmiL
. Facility or practices shall not cause
discharge oC d~ged or fill material
into waters oC the U.S-
. Facility or practices shall not
contaminate underground drinlUnl
source beyond facilities boundary.
. The concentration oC explosive gases
pcrated al the facility shall not
c:xcecd: (1) 25% oC the lower explosive
limit Cor the gases in Cacility structures;
(2) the lower explosive limit Cor the
gases at the boundary.
1. Disposal of Solid . Facility or practice shall not pose a
Waste (Continued) hazard to the saCety oC persons or
propcny Crom rtrc.
. Facility or practices shall not allow
uncontrolled public ac:ccss so as to
aposc: the public to potential health
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Table 10.3 (Page 2 ot ..)
FederaJ A.cUoo-Speclnc ARARs
A.cUoo-Specil1c CltaUoo Pruequlsl\.e Requlnmeot
B. Relevant and
Appropriate
Requirement
1. RcmovaJ at Surface Mining Control Removal oC contaminated .ll-Posting signs and marten for
contamiD.atCd soill and Rc:cl.1mauon ~ of surface soils. reclamation. including top soil markers
1977; 2S U.s.c. Hl:01 and perimeter markers.
e1 scq.; 30 CFR
PUtS 816.11, .95, .97, .95-Subilization of all exposed surtlce
.100, .102. .107. .111, 3l'C3S 10 effectively control erosion and air
.113. .114, .116 pollution attendant to erosion.
.97-Use of best technology culTCntly
available 10 minimize disturbanc:c:s and
advene impacts on fISh. Wildlife:, and
related environmental values and achic:ve
enhancement of such if possible; conduct
DO activity which would jeopardize
continued existence of endangered species
or like to destroy or advenely modify their
critical habita~ avoid disturbances to,
enhance where pr.acticable, restore or
replace. wetl.1nds, riparian VCietation. and
habiutS (or fISh and wildlife.
1. Removal at .100.Contempor.aneous redamation
contaminated soill including, but not limited to backfilling,
(continued) rett'3dinc. topsoil replacements and
revCieUtion. Achic:ve approximate
origiaaJ contours, eliminate all highwalLs.
spoil piles. and depre::s.sions;
.102.achic:ve a post action slope not
c:xcceding angle oC repose or such lesser
slope as is necessary to achic:ve a minimum
long-term static sa(ety factor o( 1.3 and to
prevent slides.
2. Thn::sbold Limit Established by AmeriClo Releases of airborne TI. Vs are based on the dc:velopment o( a
Values (I1..Vs) Coo(=ce o( contaminants during time weighted aver.age (I'WA) c:xposure to
GOYCnImc:ntal lndustnal remedial activities. an airborne contaminant aver an 8.hour
Hygienists (ACGIH). worlt day or a 40-hour worlt week. TI. Vs
identify Ic:vels o( airborne contaminants at
which health risks may be associated.
Sincc there are no ARARJ (or sever.al of
the contaminants o( concem-anenic,
antimony, copper, cadmium. mercury, and
zinc-the TI. Vs should be considered for
remedial activities which will causc
airborne emission o( such chemicals. The
TI. Vs for the contaminants of concern are
as (ollows:
Antimony SOO ,uglm3
Ancnic 200 ,uglm3
Cadmium 50 ,ug/m3
Copper (ume=2oo ,uglm3
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I Table 10.3 (Page 3 or 4) I
Federal ActIoo-Sped1k ARARs
ActIonoSpedftc Citation PreRq1USUe Requirement
2. Threshold Limil Lead 1S0 1J.g/m3
Values (I1.Vs) Mercury alkyl'" 10 1J.g/m3
(Q)ntinued) Except Alkyl:
vapor"'SO 1J.g/m3
inorganic'" 100 IJ.rlJ.n3
Zinc ZOO'" 1.000 1J.g/m3
Zinc Oxide:
fume"'S.OOO lJ.g/m3
dust'" 10.000 1J.g/m3
3. Treatment., Storage, 40 em 264.13, .14 The Irc:1tment., storage or Prevent unknowing entry and minimize the
or Disposal or disposal or RCRA regulated ?OSSibility or unauthorized entry or
Wastes wastes. pc~ns or livestock 10 the active ponion
or the Cacility. Includes:
- anificial or natural barrier completely
surrounding tbe active area
. a means 10 control entry
- a sign stating 'Danger, U~riud
Pt:TSOnnd K«p QuI.'
C. To Be Q)nsidercd
Malerials
1. Estimated Umit Established by American Releases or airborne EL VS are based on Threshold Limit
Values (ELVs) Q)nrerence or contaminants during Values (I1.Vs) and convened to reflect
Governmental Industrial remedial activities. exposure to contaminants on a 24-hourl
Hygienists (ACGrH). day basis. The calculation or an EL V does
DOt take into consideration the additive
and synergistic effects or contaminants and
additional ~ures rrom media other
than air. ELVs an: nOI apected to be
completely protective or the potential
effects or exposures to contaminants;
however, they do provide some indication
or airborne contaminant levels at which
advene health effects could occur. Since
tbere are no ARA1U ror several or the
contaminants or concern-arsenic,
antimony, copper, cadmium, mercury, and
zinc-the EL Vs should be considered ror
remedial activities which win cause
airborne emission or such chemicals. The
EL VS ror the contaminants or concern are
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Table 10-3 (P~ 4 014)
FedenJ Actloo-Specinc ARARs
AcUoo-S pecU1c I CItatloo PruequisU. RcqulnmeD&
1. ~im.1ted Umit
VaJUCl (ELV,) Antimony 10.0,.g/a!3
(continued) Anenic 5.0 JA.IIm3
Cadmium 1.0,.glm3
Copper Cumc-5.0 ,.rlm3
dllS& - ;:0.0 ,.glm3
Le:ad 4.0 JA.IIm3
Men:ury 31Icyl:aO.2,.glm3
Except AlJr.;yl:
vapor-1.0 ,.glm3
inorganic-
::'0 ,.g/!D)
Zjnc ZOO:a;:O.O ,.glm)
Zjnc Oxide:
fume-!:0,.glm3
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Table 104
Slate or Idaho ChemicaJ-Speclnc ARARs
CbemicaJ-Speclnc Citation Prerequisite Requirement
LAir
A. Applicable Requirement
1. Toxic: Substances IDAPA f}6.01.1011,Ol Emission ot air contaminants Emissions ot air contaminants
that are toxic to human which oc:cur during remedial
health, animal liCe, or activities win not be in such
v~etatioD. quantities or concentrations as to
alone, or in combination with other
contaminants, injure or
unreasonably affect human health,
animal liCe or vegetation
B. Relevant and None
Appropriate
C. To Be Considered None
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Table 10-5
Stale or Idaho l.ocalJoa-Specinc ARARs
Localioo-Spectnc Cllalioa Prenqu!sjle Requirement
L Air ~oDe
It Soil
A. Applicable Requirement
1. Areaa Adjac:au to IDAPA U6.01.:.soo Stonge or disposal of haurdous The remedial adioQ will be designed
or i4 the Vic:iJ1i ty or deleterious materials i4 the with adequate measures and controls
01 State Walen vicinity of. or adjacent to, state to ensure stored or disposed
waten. contaminated soils will not enter state
waten as a result of high water.
precipitation. runoff. wind. Catility
Cailure. accidents or third-party
activities.
B. RcJevant and
Approprute
Requirement
1. Siting 01 LC. H39.S801 Siting of a hazardous waste The remedial action will be designed
Hazardous Waste ::.5' disposal facility. to satisfy some of the tcchnicaJ
Dis~l Facility aitc:ria in the Idaho Hazardous Waste
SitinS Management Plan as adopted
by the Idaho Legislature.
Consideration will be given in remedy
design to genenl considentions .
referenced by the Hazardous Waste
Facility Siting Act. HowC'YCt'. a sitinl '
license Cor an onsite hazardous waste~
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I Table 10-6 !
Slate 01 Idaho ActJoo-Speclnc ARAR.s
ActJoo-SpecUlc Cllal10n Prerequisite Requirement
L Air
A. Applicable Requirement
1. FuptiYe Dust IDAPA n6.01.1251- Emission of airborne paniculate The remedial action will be designed
16.01.1252 matter. to lake all rcasooable precautioDS to
preYeDt particulate matter from
becoming airborne including but not
limited to, as appropriate. tbe use of
water or chemicals as dust
suppressants. the covering of trucks
and the prompt removal and handling
of excavated materials.
II. Soil
A. Applicable Requirement
1. Maoagement of 10APA U16.01.5000 Mall3gement of solid waste The remedial action will be designed
Solid Waste ~ including storage. collection, to manage solid waste to prevent
traosCer, transpon, processing. health hazards, public nuisances and
separation, treatment and pollution to the environment in
disposal accordance witb the applicable IOlid
waste management requirements. No
permit is required for onsite actions.
2. Activities IDAPA Construction and other activities The remedial action win be designed
GeDcratins Non- U16.01.20S0,06 and which may lead to non-point to utilize best management practices
point Discharges 16.01.2300,04 source discharges to surface or knowledgeable and rcasooable
to Surface Waten waten. efIons in construction activities to
minimize adverse water quality
impacts and provide full protection or
mainteoance of beneficial uses of
IUlface waters.
B. Relevant and
Appropriate
1. Management of LC. "39-4401 et Generalion, transportation, The remedial action will be designed
Hazardous Waste seq.. 10AP A storage or disposal of hazardous to mall3ge any hazardous waste that
RT6.01.5000 ~. waste. may be generated by the remedial
action in accordance witb tbe relevant
and appropriate generation,
transportation, storage and dispoaal
requirements for sucb waste. Onsite
actions are exempt from some
requirements. and permits are not
required for onsite activities.
-------
Oosure requirementS address what actions are necessary to protect public health and the
environment when the disposal action is complete. For this action, the relevant and appropriate
closure requirementS include: 1) capping to minimize airborne contaminant migration and ,
reduce the threat of direct contact exposure; 2) long-term management of the disposal site. ~
including cover maintenance and groundwater monitoring; and 3) institutional controls such as
access restrictions, land use restrictions, and/or deed notices.
Oosure requirementS and landfill design and operating requirements with respect to
groundwater and surface water protection will be addressed in a subsequent ROD.
RCRA minimum technology requirementS are not appropriate for this action because the
residential soils do not present hazards that warrant secure disposal
RequirementS of the Land Disposal Restrictions are 110t appropriate for this remedial action
bec1use the material will be moved within the AOe. Placement. as defined by RCRA. will 110t
oa:ur.
If Page Ponds is not used as the residential soils repository, the agencies will conduct an evaluation of
ARAR5 specific to the repository site chosen.
IDHW and U.S. EP A have determined that 311 state and federal ARAR.s for residential soils removal
and replacement will be met by the selected remedy. The agencies have not determined the ARARs
with respect to groundwater and surface water protection as pan of this operable unit ROD. That
determination will be made in a subsequent ROD.
10.3 COST-EFFECTIVENESS
IDHW and U.S. EP A believe the selected remedy is cost-effective in mitigating the risk posed by con-
taminated residential soils. Section 3OO.430(f)(ii)(D) of the National O:>ntingency Plan (NCP) requires
an evaluation of cost-effectiveness by comparing all the alternatives that meet the threshold criteria
(protection of human health and the environment) against three additional balancing criteria (long-term
effectiveness and permanence; reduction of toxicity, mobility, or volume through treatment; and shon-
term effectiveness). The selected remedy meetS these criteria and provides overall effectiveness in pro-
portion to itS cost.
The selected remedy includes removing and replacing contaminated soils (or placing a soil cap, where
appropriate), installing visual barriers (where applicable), revegetating, suppressing dust during
remediation. disposing of oontaminated materials, and monitoring for metals in soil. Institutional
controls will ensure long-term maintenance of physical and institutional barriers that protect against
metals exposure. This alternative is attraCtive bec1use of the relatively low cost (approximately
S41.3 million present worth) and expected effectiveness, as compared with other alternatives.
The principal difference betWeen the selected remedy and tWo of the other alternatives is excavation
depth. One alternative involves sod excavation and replacement without removal of underlying oontami-
nated soils. Although less expensive than the selected remedy, sod removal and replacement would
provide a less effective means of protecting human health and the environment. Another
alternative. which required a 7-foot excavation depth, was considered excessive. Although an excavation
depth of 7 feet would effectively remove the contaminated residential soils. the associated cost of
S193 million was substantiaJly higher than that for the selected remedy. The added remedial effec-
tiveness would be marginal with respect (0 the additional cost.
-------
An alternative with a pozzolanic treatment prior to disposal was also evaluated. Pozzolanic treatment
would be intended to reduce the mobility of contaminants, as compared with untreated contaminated
soil. However, the reduction in contaminant mobility is expected to be marginal with respect to the
additional cost of$14.7 million. Contaminants in untreated soils would be adequately immobilized when
disposed in a revegetated and properly contoured landfilL The selected alternative was therefore deter.
mined to be more cost-effective.
10.4 UTILIZATION OF PERl\1ANENT SOLUTIONS AND
ALTERNATIVE TREATMENT TECHNOLOGIES TO THE MAXIMUM
EXTENT PRACTICABLE
IDHW and U.S. EPA believe the selected remedy represents the maximum extent to which penn anent
solutions and treatment technologies can be utilized in a cost-effective manner for residential soils at the
Bunker Hill site. Of the alternatives protective of human health and the environment and that comply
with ARARs, the selected remedy provides the best balance in terms of long-tenn effectiveness and
pennanence; reduction of toxicity, mObility, volume, and persistence; short-tenn effectiveness; implemen-
tability; and cost. Also, the selected remedy considers the statutory preference for treatment as a princi-
pal element and considers community acceptance.
Long-tenn effectiveness was the primary reason for selecting Alternative 3 over Alternative 5. Twelve
inches of soil and sod provide a much more pennanent physical barrier to potential exposure than
simply a sod barrier. The institutional controls associated with Alternative 3 improved community
acceptance because the co~1trols are less intrusive compared to Alternative 5. The cost of removing soils
to a depth of 7 feet in Alternative 6 was too high compared to Alternative 3, considering the associated
incremental improvement in pennanence.
The selected remedy does utilize alternative treatment and resource recovery technologies to the maxi-
mum extent practicable. Treatment of residential soils was not found to be practicable; therefore, this
remedy does not satisfy the statutory preference for treatment as a principal element. The combination
of high soil volume, the nature of metal contamination, and the need to excavate soils from yards prior
to application of a treatment technology like soil washing made the costs of any known treatment
technology, whether proven or unproven, prohibitive. An in situ soil treatment process would have
eliminated the soil handling requirement. However, fixation or pozzolanic treatments are not consistent
with the uses of a residential yard. There are no other in situ treatment technologies known to be effec-
tive in removing metals from soiL
10.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
For the reasons descn'bed above, the selected remedy does not satisfy the statutory preference for
treatment as a principal element. However, this engineering controVcontainment remedy is consistent
with the Superfund program expectations stated in the NCP (40 CFR 430(a)(1)(iii)(B».
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RESPONSIVENESS Sm~IARY FOR THE RESIDENTIAL
SOIL OPERABLE UNIT
POPULATED AREAS
OF THE
BUNKER fiLL SUPERFUND SITE
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CONTENTS
Page
1
Overview
RS 1-1
2
Site History and Background on Community Involvement
RS 2-1
3
Summary of Public Comments and Agency Responses on the
Proposed Plan for Qeanup of Residential Soils Within
the Populated Areas of the Bunker Hill Superfund Site
RS 3-1
Section 3.1
Written and Verbal Comments Received During the Public
Comment Period
RS 3-1
Section 3.2
Comments Submitted by the Potentially Responsible
Parties (PRPs)
RS3-4
Section 3.3
Summary of Institutional Controls Meetings
RS 3-21
TABLES
1
Summary of Community Relations Activities at the
Bunker Hill Superfund Site
RS 2-3
2
Public Meetings Summary, Residential Soils Operable Unit,
Bunker Hill Superfund Site
RS 3-26
3
Fact Sheets and Other Infonnation Distributed Door to Door,
Residential Soils Operable Unit, Bunker Hill Superfund Site
RS 3-32
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1 OVERVIEW
Contaminated residential soils are the first operable unit to be addressed through a Record of Decision
(~OD) at the Bunker Hill Superfund Site. A proposed plan for residential soils remediation was issued
to the public April 29, 1991. A 6O-day public comment period began on that day and continued through
June 30, 1991. The Proposed Plan recommended removal of 12 inches of soil and replacement with
clean material at all residential yards that have soil lead concentrations exceeding 1,000 parts per million
(ppm). The Proposed Plan also required placement of a 2-inch gravel visual marker between the clean
backfill and any contaminated residual soil. Yards would be revegetated once the area is returned to
appropriate grade with clean replacement soil. The Proposed Plan stated that excavated contaminated
soils would be disposed at the Page Ponds facility. Upon completion of all soil removal, the disposal
site would be stabilited to prevent contaminant migration by wind and water erosion and closed with an
impenneable cap. One purpose of the cap was to block the leaching through the highly contaminated
underlying tailings. An institutional controls program consisting of pennitting requirements and educa-
tion and health intervention programs would be implemented to maintain the integrity of the residential
soil barriers.
Based on public comment, it appears that the public in general favored the proposed remedy. The con-
cern raised most often was that remediation should begin as soon as possible. There was public com-
ment relating to the potentially high cost associated with the grave} barrier. The Potentially Responsible
Parties (PRPs) expressed concern at the requirement to excavate 12 inches in all yards when in many
cases contamination was present in only the top 6 inches of soil. The PRPs also questioned the use of
the 1,000 ppm threshold level and the application of some parameters used to calculate the value. Ad-
ditionally, the PRPs did not believe that it was appropriate to propose an impenneable cap at the Page
Ponds disposal site to address groundwater contamination without performing a comprehensive and
integrated analysis of the groundwater contamination issue. They believed that it would be more appro-
priate to address groundwater contamination in a subsequent Feasibility Study (FS).
The selected remedial alternative, as presented in the Residential Soils Record of Decision, has been
modified in response to comments received. The recommended remedy no longer requires use of a
2-inch gravel layer as the visual marker. The marker is still required, but different materials may be
used. Less than 12 inches of soil may be removed if sampling shows that contamination does not exceed
the 1,000 ppm threshold level at depths between 6 and 12 inches. In any case, a 12-inch clean soil
barrier is required over any remaining residential soils that exceed 1,000 ppm. In addition, an
impermeable cap was required at the Page Ponds Residential Soil Repository to protect groundwater.
However, the ARARs to protea groundwater and surface water will be evaluated in a subsequent FS
and ROD.
A complete listing of all comments received from the public and PRPs and the agencies' response is
included herein.
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2 SITE HISTORY AND BACKGROUND
ON co~ruNI1Y INVOLVEl\'IENT
The Bunker Hill Superfund Study area is approximately 7 miles long and 3 miles wide, covering a
21-square-mile area encompassing the cities of Kellogg, Wardner, Smelterville, and Pinehurst and sur-
rounding residential areas. In the center of the site is the Bunker Hill mining, milling, and smelting
complex. The primary materials produced were lead, zinc, cadmium, silver, gold, and their alloys. The
lead smelter operated from 1917 to 1982 and its zinc plant from 1928 to 1982. During this period, par-
ticulates containing lead and other heavy metals were discharged through stacks and from throughout
the facilities and dispersed over the project area. Disposal of mill tailings into the river from mining
activities also contributed to metal contamination of the site.
In 1974, tWo cases of excessive lead absorption in children from Kellogg were reported. Detailed epide-
miological studies were subsequently conducted on children in the valley, and it was determined that
significant numbers of children had elevated lead levels in their blood. Numerous environmental sam-
ples were collected from their home environments including soil and vegetation from yards and play
areas, interior dust from the home, interior and exterior paint, and garden vegetables. In addition to
biological and environmental sampling, a questionnaire was administered to participants to gain socio-
economic and historical information.
Following the 1974 survey, an intensive effort was made to educate the community about the lead health
issue and the measures that could be taken to lower blood lead levels. Blood lead screenings were a
part of a community Health Intervention Program and have continued to the presenL
Since the discovery of the blood lead problem in 1974, IDHW, Panhandle Health District (PHD), and
the federal Centers for Disease Control (CDq have continuously worked with the area residentS to
reduce exposures to lead. Public meetings have been held in Kellogg to explain blood survey resultS and
to discuss public questions and concerns. Radio talk shows and news releases have also been used as a
public forum to address the lead health issues. The PHD has served as a local source of information
and education regarding lead and how exposures may be reduced.
Concerns expressed by the community over the years have been documented in the Community Rela-
tions Plans for 1987 and 1990. Some specific concerns documented during interviews with local citizens
are described below with an explanation of how these concerns were addressed. Concerns expressed in
the interviews are representative of the statements and questions asked by individuals during public
meetings.
There was concern about the potential impact of the area's Superfund status on the local economy and
property values. The U.S. EP A has worked with the Department of Housing and Urban Development
to ensure that lenders in the valley will not prevent or delay sales of property due to the Superfund
designation. The U.S. EP A and PHD have also worked to help educate lenders about lender liability
issues. Hiring of local workers for any Superfund work was encouraged within the framework of fair
hiring practice regulations. The U.S. EP A has also signed a .covenant not to sue. agreement to facili-
tate construction of the Silver Mountain gondola. The gondola project is expected to help enhance the
local tourism industry.
Questions about the amount of time it is taking to clean up the site were asked in several different
forums. To address this concern, the agencies split the site into smaller operable units so that the work
can be initiated as study of each unit is completed. For example, studies for the Residential Soils opera-
ble unit were completed before the studies for other units which allowed the agencies to select the
cleanup remedy for residential soils before the completion of other studies.
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Inquiries about the participation of the PRPs were received on several different occasions. The agencies
have worked with a PRP in completion of the Non-populated Areas Remedial Investigation Study. A
consortium of PRPs has come together to propose a cleanup plan for the entire site. This plan is being
evaluated through the Superfund RIJFS process. The agencies are working with the PRPs to complete
the RIfFS and develop a plan to address remaining issues.
Concerns about blowing dust have been expressed over the years. Specific concerns are the health
impactS from exposure to dust and rewntarnination of areas that have been remediated through the
1986, 1989, and 1990 removal actions. Owners of dust source properties were asked by the agencies to
control dust throughout the project. In addition. specific orders were issued to require the PRPs to
control dust on at least a temporary basis until a final remedy for dust control in specific areas is
selected.
ImpactS on land use of the residential soil cleanup and cleanup of the rest of the site is a concern that
was voiced by community leaders and 10Cl1 citizens. The agencies are working closely with the commu-
nities through the PHD to develop an institutional control system that minimizes impactS on an individ-
ual's land use.
There was concern about the continued health risks for children and adultS living in the valley. The
agencies have worked closely with the Agency for Toxic Substance and Disease Registry (ATSDR) and
the CDC to address community health concerns. Workshops and public meetings have been held to
discuss the risks associated with living in residential areas onsite and how these risks can be minimized.
Several specific health questions were presented by the state in response to community concerns at a
public meeting and were answered by ATSDR The Community Health Intervention Program has also
been ongoing to help address health concerns. Homes of young children and pregnant women were
considered a priority for soils removal
To facilitate community involvement. the Shoshone County Commissioners selected a nine-member tas
force to serve as a liaison committee betWeen the community and the Bunker Hill Superfund Project
Team made up of U.S. EP A. IDHW, and PHD staff and contractors. Four public information reposi-
tories were also established onsite. Table 1 includes: locations of the repositories; a'summary of the
number of task: (orce meetings, and meetings held with other community groups; the number of fact
sheetS and other information; and identification of local contactS. Tables 2 and 3 list the public meet-
ings held with tbe taslc force and the fact sheetS and other information distributed door to door to every
residence within the site. respectively.
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Table 1
Summary of Community Relations Activities at the Bunker Hill Superfund Site
May 1985 to July 1991
Public Information Repositories
Kellogg City Hall
323 Main Street
Kellogg, ID 83837
2081786-9131
Kellogg Public Library
16 W. Market Street
Kellogg, ID 83837
2081786-7231
Smelterville City Hall
Smelterville, ID 83868
2081786-3351
Pinehurst-Kingston Library
107 Main Avenue
Pinehurst. ID 83850
208/682-3483
Task Force Members (Nine representatives from the local communities)
Public Task Force Meetings (35)
1985 (6); 1986 (8); 1987 (6); 1988 (6); 1989 (4); 1990 (3); 1991 (2)
Meetings With GroupS/Civic Organizations (~)
1985 (5); 1986 (13); 1987 (10); 1988 (14); 1989 (11); 1990 (12); 1991 (19)
Includes meetings with:
Elected Officials Kiwanis
Idaho Citizens NetWork Boar~ of Realtors
Lions Club KEA
School District Gondola Committee
Sewer District Nonh Idaho Pensioners
Chamber of Commerce Clutch
American Association of Mining Engineers Clean Lakes Coordinating Council
Project Uplift Industry
Homeowners
Meetings With Fair Share/Idaho Citizens Network (18)
Fact Sheets and Other Information (Distributed Door to Door) (25)
Local Contacts (2)
Jerry Cobb Scott Peterson
Panhandle Health District IDHW Project Office
P.O. Box 108 10 E. Station Avenue
Silvenon, ID 83867 Kellogg, ID 83837
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3 SUMl\tIARY OF PUBLIC COMMENTS AND AGENCY
RESPONSES ON THE PROPOSED PLAN FOR
CLEANUP OF RESIDENTIAL SOILS WITHIN THE
POPUlATED AREAS OF THE
BUNKER IDLL SUPERFUND SITE
This responsiveness summary addresses the comments received by U.S. EP A and IDHW concerning the
Proposed Plan for Oeanup of Residential Soil within the Populated Areas of the Bunker Hill Superfund
Site. Comments and questions raised during the public comment period are summarized below. Several
of the comments addressed similar concerns and have been grouped accordingly. The summary of com-
ments has been organized into three sections for clarity:
1.
Comments received from the public at large
2.
Comments received from the Potentially Responsible Parties (PRPs)
3.
Public officials' comments on the Institutional Controls Program
Copies of the transcript for the meeting and comment letters received are available in the Residential
Soils Administrative Record located at the Kellogg Public Library.
3.1 WRITIEN AND VERBAL COMl\1ENTS RECEIVED
DURING THE PUBLIC COl\'IMENT PERIOD
3.1.1
WRITIEN COMMENTS RECEIVED FROM AREA RESIDENTS DURING THE PUBUC
COMMENT PERIOD
Comment: One commenter believed that the inclusion of a gravel layer as a visual marker was excessive
based on its cost and the impact that cost would have on the Potentially Responsible Panies.
Response:
The purpose of the gravel barrier is to provide a visual indication to homeowners who,
during normal activities such as installing a fence or remodeling a home, may encounter
buried contaminated soils. The selected alternative will include some type of visual
barrier. It is anticipated that the cost of the barrier will be reduced by considering
alternative materials to gravel This will alleviate the concern regarding cost while still
providing a visual barrier.
Comment: One commenter stated that there should be variable excavation depths rather than a set
depth for all properties.
Response:
An allowance for a variable removal depth has been included in the Record of Deci-
sion. The depth of removal will be based on a specific sampling and analysis plan.
Regardless of the depth of removal, there will be a 12-inch soil column in place in each
yard with a soil lead concentration less than 1,000 ppm at any interval.
Comment: One commenter stated that the No Action Alternative should be selected. Decreasing blood
lead levels were proof to the commenter that further expenditure of funds is unnecessary.
-------
Response:
Although blood lead levels have been decre3Sing over time, they are currently at unac-
ceptably high levels. Further reduction through environmental remediation is therefore
required. The agencies believe that selection of the No Action Alternative would no
be protective of human health and the environment.
Comment: One commenter asked that the residents who had lived in the area the longest be given
priority for yard remediation rather than the younger children who might have recently moved into the
valley but fit the age criteria for yard remediation.
Response:
Residential soil removal activities in the past were prioritized based on sensitive sub.
populations (young children and pregnant women). Future actions will be based on the
goal of obtaining a comrnunitywide soil lead concentration of 200 to 300 ppm lead in
soil with an action level of 1.000 ppm rather than sensitive sub populations. The
sequencing of the residential yards to be remediated will be determined in the next
phase. the remedial design portion ot the project. However. sensitive populations will
continue to be prioritized.
Comment: One commenter wants asphalt installed on road shoulders betWeen paved roads and residen-
tial yards since gravel shoulders could ~h away. exposing contaminated material.
Response:
A 12-inch layer of soil will be removed from road shoulders where appropriate and will
be replaced with material as required by 10Cl1 and state government regulations.
Comment: One commenter would like a lined landfill designed and constructed on the old Bunker Hill
site to serve as the county landfill.
Response:
It is anticipated that a repository (or residential yard soil will be created onsite
However, it is not anticipated that it will be able to accept municipal solid waste fro
the area residents. The design and operational standards for a municipal landfill are
different than those required for a residential soil repository. Also, the addition of
municipal solid waste into the soil repository may exacerbate metals migration through
the production of leachate which is generated when water runs through waste material
and picks up contaminants which may then enter groundwater.
Comment: One commenter was concerned that the (e3Sibility study and proposed plan did not address
the groundwater. Without considering the groundwater, the commenter notes, the long-term
effectiveness ot the remediation is in question. The commenter stated that Applicable or Relevant and
Appropriate Requirements should have been considered (or groundwater.
Response:
The feasibility study and the proposed plan specifically stated that a groundwater
remedy was not being considered in the documents supponing the residential soil
operable unit. Groundwater issues are being considered on a larger sitewide basis in
order to address the many potential sources of contamination. Groundwater will be
addressed in a separate ROD at a later date.
3.1.2 VERBAL COMMENTS FROM mE PUBUC HEARING
Comment: Four commenters expressed their suppon for the Preferred Alternative and a strong desire
to move forward with the remedial portions of the project and not let it drag on (or many years.
Response:
Initially. the site was split into tWo separate RUFS efforts in order to, among ather
things. expedite the RVFS process in the Populated Areas of the site.
-------
The agencies believe that there is community acceptance for the Preferred Alternative
as indicated in the Proposed Plan. The agencies are committed to remedial action as
soon as possible in the residential areas of the Bunker Hill Superfund Site.
Comment: One commenter wants residential ):arc1s put back to equivalent or better condition than when
cleanup action was initiated.
Response:
It has always been a goal during residential soil remediation to restore yards to an equi-
valent or better condition than before cleanup. This will continue to be a goal in the
future and. as the remedial aCtivities progress, construCtion requirementS to achieve this
goal will be improved.
Comment: One commenter wants to see the Health Intervention Program continued and a trust fund
established for health prevention in the community.
Response:
It is anticipated that the Health Intervention Program will be continued as part of the
institutional controls program. Issues of health effects related to past exposures have
been referred to ATSDR for consideration.
Comment: One commenter would like the priority for jobs during the remedial action to be given to
local residents to help defray the high unemployment in the valley.
Response:
The agencies have always encouraged and hired local citizens to assist with the Super-
fund process where it is appropriate. In the event that private companies are
responsible for carTjing out remedial activities, the agencies will encourage them to hire
local citizens. However, hiring decisions will be the prerogative of the private
companies.
Comment: One commenter wants the feasibility studies completed as soon as possible so that public
comment can take place and the remedial decisions can be made part of the final Master Plan. In a
similar comment. another commenter wanted the residential soil removal to be conducive to the Master
Cleanup Plan.
Response:
The feasibility study and proposed plan for the residential soils in the Populated Areas
is complete. The remediation of residential soils will take place as soon as possible.
The agencies currently intend to integrate residential soil remediation with Olher
remedial activities onsite.
Comment: One commenter recommended and stressed that all concerned parties work together.
Response:
The agencies continue to work with aU interested parties and welcome input from those
parties. Public participation has oo::urred throughout the RIJFS process and will con-
tinue in the future.
Comment: One commenter was concerned about the Superfund designation hurting investment
Opportunity and wanted the U.S. EP A and the PRPs to start the actual cleanup of the lead smelter, zinc
plant, and Central Impoundment Area (CIA).
Response:
The cleanup of the areas specifically addressed in the comment are separate from the
residential soils within the Populated Areas of the Bunker Hill Superfund Site. These
areas are being addressed in the Non-populated Areas RIIFS.
Comment: One commenter expressed support for the 1.000 ppm action level.
-------
Response:
Based on the Risk Assessment Data Evaluation Report (RADER), the agencies believe
that the selection of the 1,000 ppm action level for residential soil remediation will
protect human h~lth.
3.2 COi\:Il\-IENTS SUBI\-llTIED BY THE
POTENTIALLY RESPONSIBLE PARTIES (PRPs)
Comments were received during the public comment period from three potentially responsible parties:
ASARCO Incorporated, Gulf Resources & Chemical Corporation, and HECLA Mining Company on
U.S. EP A's proposed plan for cl~nup of residential soil within the Populated Areas of the Bunker Hill
Superfund Site. Comments were received in a document organized in the following format:
I.
The FS SupportS at ~fost Selection of Alternative 5
II.
EP A's Designation of 1.000 ppm Soil a~nup Level is Not Consistent with Sound Science or
This Record
A
c.
EPA's Establishment ora 10 ~g/dl Remedial Action Objective is Unjustified
B.
EP A Employed Several Inappropriate Values in Applying the Biolcinetic Model
EPA Employed an Overly Conservative Geometric Standard Deviation in Analyzing the
Biolcinetic Model's Output
D.
When Appropriate Values are Employed. the Biolcinetic Model .SupportS a 1,900-ppm
Soil Lad a~nup Level
III.
To the Extent an ExClvation Remedy is Adopted, Several Aspects of Alternative 3 Should be
Eliminated or Revised
IV.
V.
A
Universal 12-Inch Soil E.'(cavation is Unjustified
B.
The Proposed Gravel I...ayer is Unnecessary
c.
The FS Improperly Addresses the Page Ponds Disposal Site
The Proposed Institutional Controls Program Must be Revised
A.
The Scope of the Institutional Controls Program Should be Limited
B.
A More Cautious Approach to Program Implementation is Required
Miscellaneous Other Comments
In order to easily correlate responses to comments, the above-ordered format of the comments has been
maintained as much as possible. In many cases there was supporting text for each comment. Responses
have been developed for the general comments and the supporting text as much as possible.
-------
COMMENT I: The FS Supports at Most Selection or Alternative 5; "There are nine criteria for
evaluation of remedial alternatives: ...Properly explained by EP A. Alternative 5 appears to meet them
all. The only significant reservation EP A has expressed about Alternative 5 is that sod would not hold
up over time, or would not be well maintained. ...The record is devoid of information, however, to
suggest that, when properly maintained, sod replacement would not provide long-term remediation at
the site. Nor does it raise substantial doubtS that sod can be maintained."
Response:
The commenter is correct that there are nine criteria against which each remedial
action alternative is judged. However, the cornmenter is incorrect is stating that Alter-
native 5 meetS all of them. The last criterion is Community Acceptance. Public
commentS have been received in the past regarding the potential burden of the
Institutional Controls Program. Since the residentS of the site prefer the least burden-
some institutional controls program, the agencies suppon Alternative 3 rather than
Alternative 5 since it is judged to have a less burdensome institutional controls pro-
gram. CommentS were received during the public comment period in favor of Alterna-
tive 3 while no commentS, with the exception of those from the Potentially Responsible
Panies, were received in suppon of Alternative 5. Therefore, there is greater
community acceptance of Alternative 3.
Also, the long-term effectiveness of Alternative 5 is questionable. The FS states:
"Although Alternative 5 constitutes a reliable shon-term solution, it requires a labor-
and enforcement-intensive effon for long-term success. The permanence of Alterna-
tive 5 is directly related to maintenance of the protective cover. Alternative 5 has the
lowest long-term effectiveness of all alternatives (with the exception of the No Action
Alternative. )
The agencies are not suggesting that a properly maintained sod barrier would not meet
the long-term effectiveness criteria. However, the agencies do have reservations, and
these are significant reservations as suggested by the commenter, that the maintenance
of the sod barrier over a long time period would be extremely difficult. The long-term
effectiveness of Alternative 5 was judged to be the least with the exception of the No
Action Alternative.
The comment states that the FS is "devoid of information" that the sod layer would not
be an effective long-term alternative. It should also be pointed out that the commen-
ters presented no supponing information regarding the efficacy of a sod layer as an
effective long-term remedial alternative. In shon, there is little information regarding
long-term effectiveness of a remedial alternative instituted on such a large scale. There-
fore, the agencies believe it is appropriate to select an alternative (Alternative 3) which
logic suggestS has greater long-term effectiveness, has more state and community
acceptance, and has a less stringent institutional controls program.
Alternative 5 is the easiest to implement and the least costly of all alternatives consid-
ered, with the exception of the No Action Alternative. The agencies do not consider
Alternative 5 to have the long-term effectiveness of Alternatives 3, 6, or 8. The crite-
rion of long-term effectiveness was judged to be significant enough to not select Alter-
native 5 as the Preferred Alternative. Based on these commentS, the agencies' selection
of Alternative 3 is judged to provide greater protection of human health and the
environment.
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COMMEYf II: EPA'S Designation or a 1,000 ppm Soil Cleanup Level is Not Consistent With Sound
Science on This Record
Response:
The U.S. Depanment of Health and Human Services' .Strategic Plan for the Eliminarion .
of Childhood Lead Poisoning" (February 1991) has identified adverse health effects
associated with 10 ~g/dl blood lead and have proposed 10 ,u.g/dl as the definition of lead
poisoning in children.
U.S. EP A and IDHW have identified 10,u.g Pb/dl blood as the appropriate Remedial
Action Objective for this site.
The agencies disagree with the commenter's assenion that the remedial aCtion objeCtive
is unsupponed and unnea:ssarily conservative. This is a conclusion drawn by the com-
menters and appears to be based on the commentS found under ILA through II.D. (as
follows). The agencies are responding to a situation at the Bunker Hill site where
imminent and substantial endangerment existS for area residentS. The agencies believe
that while the attainment of natural background contaminant levels in soils and dustS in
the Silver Valley would offer the most protection to the community .relative to heavy
exposures. it is less than practical. Therefore. U.S. EP A and IDHW have identified as
a remedial goal the reduCtion of heavy metal exposures to levels that would minimize
(but not necessarily eliminate) adverse effects to sensitive populations in the study area.
The administrative record shows that the implementation of a 1.000 ppm Soil Lead
Cleanup Th~hold yields a maximum soil lead concentration for any individual yard at
less than 1.000 ppm with community mean soil lead concentrations of 122 ppm,
121 ppm. 174 ppm. 278 ppm. and 275 ppm for Smelterville, Kellogg, Wardner. Page,
and Pinehurst, respectively. House dust lead levels are expected to exhibit a conseque
reduCtion bec1use of residential yard soil remediation. The administrative record, sp
cifically the RADER, presentS the methodologies and associated data used for evalu-
ating and determining the soil lead cleanup threshold identified in the remedial plan for
residential yard soils. These reduCtions in environmental lead levels and implementa-
tion of an institutional controls program are componentS of a comprehensive plan
designed to achieve the remedial objective by reducing environmental exposures to
sensitive populations.
Several faCtors were considered in the agencies' seleCtion of the 1,000 ppm Soil Lead
Cleanup Threshold. The agencies believe all were consistent with sound science and
the project record. The selected cleanup tbreshold is based to a large degree on analy-
ses of tbe site-specific data base available for tbis population. This data base has accu-
mulated over 17 years of epidemiologicl data following the identifiction of community
cbildhood lead poisoning.
Input parameters used in the dose-response modeling, as it has been applied at the
Bunker Hill site, are site-specific and may not be appropriate for other sites. Input
parameters have been validated for preremedial conditions using the site's epidemiolog-
ical data base. Use of the model for determination of threshold soil and dust lead
cleanup levels has not incorporated any uncertainly or safety factors for the estab-
lishment of remedial goals. The agencies believe that the dose-response modeling has
been balanced. based on site-specific observations, and does not incorporate the margin
of safety usually applied in evaluations where less epidemiologic data and more
uncenainty are found.
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Comment II.A.: EPA'S Establishment of a 10 JLgldl Remedial Action Objective is Unjustified
Response:
In order to evaluate unnecessary and adverse exposures of sensitive populations (0 lead,
U.S. EP A and IDHW have reviewed and considered most of the available scientific,
technical, and health/toxicological literature, as well as consulted with knowledgeable
health authorities (see Sections 3.5.1.5 and 5 in the Protocol Document and
Section 6.22 in the RADER). This evaluation is required to suppon a cleanup plan
that is protective of public health. While the uncenainties identified with (the subtle
and chronic) health effects descn1>ed in low-level lead exposure studies are recognized
by the agencies as well as the commenters, the remedial plan, nevenheless, must
consider those uncenainties and make assumptions that err. on the side of both
individual and community protectiveness. (Federal agencies, including A TSDR and
EP A. have identified a blood lead threshold of 10 JLg/dl for sensitive populations for the
protection of community health.) Specifically, U.S. EPA and IDHW have established a
community blood lead remedial action objective of s 10 JLg/dl blood for greater than
95 percent of the childhood population with not more than 1 percent of the population
exceeding 15 JLg/dl. This objective is consistent with the Clean Air Scientific Advisory
Committee's finding that blood lead levels in the range of 10 to 15 JLg/dl warrant
avoidance. In addition, the committee concluded that there was likely no blood lead
threshold level at which adverse health effects did not occur and that all practical steps
should be taken to minimize childhood lead exposures. The agencies are also aware
that the childhood blood lead level of concern has been decreasing and that funher
reductions are likely.
Comment ILB.: EPA Employed Several Inappropriate Values in Applying the Biokinetic Model
Response:
The use of a 42 percent respiratory absorption/deposition value for lead in air is justi-
fied and based on earlier studies as cited in both the RADER and Protocol Document.
A lower value, such as 32 percent used as the default value in the LEAD4 model, does
not significantly affect the model results and would only increase slightly the lead con-
tribution from ingested soils and dusts. The use of a lower respiratory adsorption/
deposition value would result in a greater soiVdust lead dose coefficient and thus a
lower soil lead cleanup threshold « 1,000 ppm) for remediation.
u.s. EP A assumed a 100 ppm lead in replacement soils rather than a lower value in
order to allow some minimal recontamination of the soils used for replacement
(typically, 60 ppm lead). Soil recontamination rates in some parts of the site have been
observed to range from 10 to 100 ppmlyr. The use of 100 ppm soil lead for a
replacement value in the site model allows for approximately 2 to 10 years for
completion of the comprehensive plan. Any longer than 2 years requires the use of a
greater value for replacement soils and the need for a lower « 1,000 ppm) soil lead
cleanup threshold for remediation.
An air lead level in remediated areas of 0.14 JLg/m3 (which is the current annual mean
air lead level) was assumed since the comprehensive remedial plan for dust control has
not been finalized, nor has a site-specific air lead control value been established. It
should be noted that post-remedial air lead level greater than 0.14 JLg/m3 is expected to
result in unacceptable environmental exposures for sensitive members of the commun-
ity. Allowing the air lead concentration to approach the current federal legal limit of
1.5 JLg/m3 is unacceptable for the site, since the soil lead cleanup threshold was deter-
mined using an air lead limit of 0.14 J.Lg/m3. It has been suggested that the federal limit
as an enforcement standard would have been an appropriate model input parameter for
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determining the soil lead cleanup threshold (which would have resulted in a soil lead
cleanup threshold < 1.000 ppm).
Comment II.Co: EPA Employed An Overly Conservative Geometric Standard Deviation in Analyzing the
Biok.inetic ~Iodel's Output
Response:
Communitywide childhood blood lead variability, expressed in tenns of the geometric
standard deviation (GSD), bas ranged from 1.65 to 1.77 during 1988 through 1990.
Town/city childhood blood lead GSDs for tbe same period ranged from 1.59 to 1.85; the
childhood population in Page (a minimally impacted community in tbe site) exhibited a
GSD ranging from 1.62 to 1.85. Lower GSDs, including a GSD of 1Al. appear to be
reasonable for describing population blood lead variability in areas exhibiting high uni-
Cormity and consistency in environmental lead contamination due to limited point
source contnoutions. While mean blood lead levels at this site have decreased since tbe
early to mid-l97Os, the variance relative to the mean (or range) has increased during
the same period. This suggestS that multiple and various sources of lead contamination
exist and have been unmasked in the residential areas CoUowing the elimination of pri-
mary point source emitters. The elimination of remaining contaminated media and
sources tbroughout tbe site, including tbose found in tbe Non-populated Areas, may be
expected to lower the post-remedial blood lead variability in the residential areas.
However, without being able to address the post-remedial conditions in the Non-
populated Areas at this time, tbe evaluation of post-remedial blood lead response was
acxomplished using a range of GSDs, 1.42 through 1.71. Higher GSDs are
recommended if any potential existS for post-remedial increases in environmental lead
concentrations resulting from transpon of contaminated dustS and soils to residential
areas from Non-populated Areas or other contaminated sources. Use of higher GSDs
are warranted if the effectiveness of the long-term remedy for the entire site.
compromised. and if significant change and .diversity in population behavior.
characteristics for future populations occur at the site. In addition, use of the higber
GSDs could offer some margin of safety in the event any of the assumptions applied in
the model were not appropriate Cor the post-remedial environmenL For example, if the
1OW- soil/dust lead dose coefficientS observed historically for tbe site fail to continue
under post-remedial conditions, tbe l,(XXJ ppm cleanup thresbold may not be sufficient
to meet the remedial objective. In this case, tbe application of the more conseryative,
or higher, GSDs would help offset any excess exposures.
~
Post-remedial response and variability in the residential areas are expected to approach
the community responses recently c:xhibited in the least impacted ponions of the resi-
dential areas of the Bunker Hill site, such as Page and PinehursL Perimeter communi-
ties of the site with mean lead concentrations in soil and dust less than 1,000 ppm
(where 20 to 37 percent of residential soils are greater than 1,000 ppm) exhibit child-
bood blood lead GSDs ranging from 1.59 to 1.85.
Comment II.D.: Wheu Appropriate Values are Employed, the Bioldnetic Model Supports a 1,900-ppm
Soil Lead Cleanup Level
Response:
Contrary to the recommendations of the commenters, the 1,000 ppm soil lead threshold
is not .overly conservative: U.S. EP A and IDHW believe the PRP assenion is
incorrect, and a soil lead cleanup threshold of 1,900 ppm for this community would
result in a >30 percent likelihood of an individual child exceeding a blood lead level of
10 }.Lg/dl and a 5 to 25 percent likelihood of exceeding 15 }.Lg/dl. Both risks are
unnecessarily high and considered unacceptable. A soil lead cleanup threshold of
1.000 ppm is expected to protect 95 percent of the children to a blood concentrati
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less than 10 mg/dl. In Smelterville and Kellogg, implementation of the 1,000 ppm lead
threshold requires remediation for approximately 90 percent of the residential soils,
which are some of the highest lead-contaminated soils in the Populated Areas. Seven
to nine percent of the soils in this area (Smelterville and Kellogg) are between 500 and
1,000 ppm. Following the completion of remedial efforts, from 91 to 93 percent of the
soil lead concentrations in Smelterville and Kellogg will be less than 500 ppm.
The identified threshold level of 1,000 ppm for lead in soils and dusts, in some parts of
the community and for some childhood behaviors, may not be sufficiently protective. If
children frequent areas with soil lead levels much greater than mean levels (approxi-
mately 200 to 300 ppm) established in the residential areas of the site following remedi-
ation, then blood lead levels could exceed the criterion established as the goal under
the remediated plan. Higher offsite exposures to children would require considering
lowering the residential soil lead threshold in order to offset excess offsite exposures.
The 1,000 soil lead threshold in Smelterville, Kellogg, and Wardner is sufficiently pro-
tective of health if children remain in the residential areas and do not become unneces-
sarily exposed to high lead levels in the nonresidential portions of the site.
In Page and Pinehurst, where implementation of the 1,000 ppm lead threshold requires
cleanup of approximately 37 percent and 20 percent, respectively, of the residential
soils, a reduction in community blood lead levels is not expected to be as significant as
in other portions of the residential area. This is due primarily to two factors: 1) after
cleanup, community mean lead concentration for soils will be greater than in
Smelterville, Kellogg, and Wardner; and 2) the soil/dust lead dose coefficient is approxi-
mately twice that found in most of the other residential portions of the site. Following
the completion of remedial efforts, from 64 to 70 percent of the soil lead concentra-
tions in Page and Pinehurst will be less than 500 ppm (as compared to -92 percent ~n
Smelterville and Kellogg). The remedial plan calls for post-remedial follow-up and
monitoring as a component of the institutional controls.program in order to ensure that
health-based remedial goals have been achieved throughout the site.
U.S. EP A's analyses of environmental lead effects have undergone extensive sensitivity
analyses for determination of reasonableness, and in almost all cases represent mean
values (or possible ranges in uptakes and blood lead response distributions. Several of
the mOdel input parameter values that were used for the determination of the soil lead
cleanup threshold, such as the soil/dust lead dose coefficient and the post-remedial daily
dietary lead intake, are lower than the values recommended in LEAD4. This results in
a soil lead cleanup threshold that is higher than that estimated using default values
found in the LEAD4 modeL The remedial threshold for soil lead levels determined for
this site is site-specific. While it is not projected to be 100 percent protective, it is
expected to be protective (or most (at least 95 percent) o( the sensitive population.
People who continue to have high blood lead concentrations after cleanup may require
additional intervention efforts as pan of the Institutional Controls Program.
In summary, the input parameters applied in the IUIBK model for the establishment of
a soil/dust lead remedial threshold were for a population and environmental conditions
that have typically exhibited a relatively low blood lead response. The current charac-
teristics of the site and its population may not be representative of conditions after
cleanup. Factors that suppon an evaluation of remedial effectiveness as remedial ef-
forts proceed are: 1) public awareness and perception of the hazards associated with
post-remedial environmental contamination are not expected to be as keen as prior to
remediation; 2) the soil/dust lead dose coefficient for some ponions of the community
(especially in the perimeter areas of the site) are greater than the mean determined in
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the central portions of the site; and 3) there is the lack of a safety or uncertainty factor
for establishment of a remedial threshold for lead..amtaminated soils and dusts.
COM:\IENT nl: To the Extent An Excavation Remedy is Adopted, Several Aspects or Alternative
Should Be Eliminated or Revised
Comment m. A.: Universal 11.Inch Soil E.'tC3vation is Unjustified; Even if EP A could justify a 12..inch
protective soil cover where excessive lead concentrations remain at lower soil profiles, there is no logiC31
reason why the soil could not be tested at a 6-inch depth, and soil removal limited if the soil does not
exceed the action level at that point. .
Response:
The agencies agree that if contamination greater than the threshold level does not exist
below 6 inches, a 6-inch eXC3vation depth would be acceptable.
Comment nr. B.: The Proposed Gravel Layer is Unnecessary; To the extent a visual barrier is valuable,
there Jre signifiC3ntly simpler. less expensive, and equally effective ways to designate the cutifilliine.
Response:
The primary purpose of the gravel barrier is to provide an easily identifiable interface
betWeen remediated and nonremediated soils. The agencies do not believe that the
barrier should be eliminated since it is an important part of the institutional controls
program. Also, the agencies do not agree with the commenters' assertion that it "gener-
ally will be readily apparent to any person digging at a remediated property where "new"
fill ends and native materials begin."
Although the agencies believe tbat a physical barrier is necessary, the construction
materials used for the barrier will be determined in the Remedial Design phase of the
project. A gravel barrier was evaluated in the Feasibility Study since it is a readil)::
available and commonly used construction materiaL
Comment III. C.: The FS Improperly Addresses the Page Ponds Disposal Site; CQmmenters believe that
the use of Page Ponds as a final disposal site is not appropriate if the site would then be subject to
regulation as a hazardous waste facility.
Response:
When evaluating AppliC3ble or Relevant and Appropriate RequirementS (ARARs) for
the site, RCRA must be considered. However, RCRA in its entirety is never "automati..
C31ly" applied. Indeed, only portions of RCRA may be considered as ARARs.
The agencies agree that the ARARs associated witb groundwater (and surface water)
. will be evaluated in a subsequent FS and ROD. The requirementS associated with the
Page Ponds repository for this ROD focus on airborne migration, direct contact, and
maintenance.
COl\fMLVf IV: The Proposed Institutional Controls Program Must Be Revised
General Response: The remedy selected for Residential Soils within the Populated Areas of the Bunker
Hill Superfund Site includes both engineered and nonengineered controls. The goal of
this cleanup action is to break the pathway betWeen contaminantS in residential soils
and the people living on those properties. It is not feasible to remove or treat all the
contamination associated with residential yards because of the depth of contamination
at some residential properties. However, the agencies believe it will be protective of
human heahh to provide a barrier betWeen the at-depth contamination and residentS,
provided that the integrity of the barrier is maintained. One oC the purposes of the IC?
is to ensure the maintenance of barriers placed during the residential soils remediatio
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Section III of this Responsiveness Summary outlines the extensive community
involvement activities the agencies employed in seeping, evaluating, and choosing an
Institutional Controls Program that: 1) minimizes inconvenience and loss ~f land use;
2) utilizes existing entities (does not create an additional bureaucracy); and 3) is self..
sustaining while not imposing additional costs on local government, residents, or
property owners.
The purpose of the report titled An Evaluation of Institutional Controls for the Populated
Arew of the Bunker Hill Superfund Site was to evaluate various ICP options designed to
provide a perpetual maintenance program for the installation, management. and
replacement of barriers established during the cleanup of the Bunker Hill Superfund
Site. While some of the ICP requirements evaluated in the above-mentioned document
focus directly on maintenance of barriers established in residential yards, the report
went further in assuming that there may be ICP requirements associated with the
cleanup of other pans of the site. Therefore, there are pieces of the ICP that were
evaluated. but are not being required as part of this Record of Decision (ROD),
because this ROD focuses only on creating barriers in residential yards and the
institutional controls associated with those barriers. The ICP associated with this ROD
is intended to protect the integrity of the current and any future, barriers placed in
service, update and maintain the community awareness/education effort, and provide
monitoring and enforcement functions.
It is expected that once sitewide cleanup decisions are made, the ICP will need to be
expanded to include any additional requirements associated with those decisions.
Comment IV .A.: The Scope of the ICP Should Be Limited; The commenters state that properties with
a soil lead concentration less than the threshold level should be treated differently than those with
concentrations above the threshold leveL "Fully excavated" yards should not be subject to a special
disposal system or be provided with "clean dirt services..
Response:
The ICP associated with this ROD is structured to be a comprehensive and integrated
program. In addition to the program being designed to maintain clean barriers, it is
also intended to: 1) maintain records of which properties are clean, partially
remediated, scheduled for remediation, unremediated, or under construction; 2) track
various activities and ensure that a system is maintained whereby contaminated soils are
not intermixed with clean soils; and 3) monitor activities or processes whereby a "clean".
parcel may be contaminated from outside sources such as unauthorized dumping or
erosion. The agencies agree that a .clean. yard may not need to be subject to the same
requirementS as a yard that is not fully "clean.; however, it is necessary for all yards to
be tracked by a sitewide Institutional Controls Program.
The agencies believe that it may not be necessary to subject property owners with con-
taminant levels below the threshold level to special disposal requirements. However,
until there is a system to sample, monitor, and document the "cleanness" of a specific
property (both at the surface and at-depth), it is impossible to delineate between which
properties should be subject to the special disposal requirements. The ROD requires
implementation of an ICP that meets the physical and administrative needs outlined in
Section 9 of the ROD. Part of the implementation or design of the ICP must include
prescribing procedures for delineation of properties with respect to contaminant con-
centrations (i.e., development of a data base).
The requirement for provision of "clean dirt" is intended to ensure maintenance of
barriers and provide a safe medium for gardening. There may be properties that do not
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meet the requirements for remediation but have owners that are interested in growing
their own produce. "Oean clirt" will be made available to any residential property
owner for the purpose of establishing a produce garden.
Comment: The ICP must recognize that in some areas and for some uses the terms of sale and existing
development standards will result in "remediation" at" many properties. The same controls that apply to
developed property should not necessarily apply to undeveloped property.
Response:
The agencies recQgnize that there is potential for "remediation" to occur as a require-
ment of a real estate sales contract or as part of normal development requirements
imposed by local flood plain ordinances and construction requirements associated with
performance standards required by local land use ordinances. However, for this ROD,
the ICP (ocuses on implementation. management. and maintenance of residential soils
barriers only (Le., barriers placed in residential yards in current residential areas). If
the ICP is expanded as part of another ROD to include areas with development poten-
tial. requirements as.sodated with development will be specified at that time. While
such properties are not specifically included among the residential properties subject to
remediation under this ROD, these properties may also be subject to institutional
controls.
The ROD does include some undeveloped properties (see Figures 1-3 through 1-7 in
the ROD) in and around current residential areas that will be included in the
residential soils remedial effort. These properties become informal play and activity
areas (or children. and the agencies believe they require a protective barrier. The
barrier at undeveloped properties will be no different than those at developed
properties.
Comment IV.B.: A More Cautious Approach to Program Implementation is Required; The commente
do not believe the feasibility study analysis, specifically estimates of costS, is sufficiently substantiated to
support re:lSoned and lawful decisionmaking. An interim program could be implemented for 5 to
7 years while "other remedial activities" proceed that would allow for identification of ICP needs and
realistic cost estimates. Commenters suggest that during the "remediation period; the disposaUclean dirt
system might be supplied by a group of potentially responsible parties, if they are implementing the
program.
Response:
The agencies believe that the institutional control evaluation entitled "An Evaluation of
Instirutio1WJ Conrrolr f(N' W Populm~d Ar~tU of lh~ Bunker Hill Superfund Sire, . which is
pan of the Residential Soils Feasibility Study, and is included as pan of the
Administrative Record for the Residential Soils ROD is sufficient to support the Resi-
dential Soils Institutional Controls Program (ICP). At this time, the agencies have
estimated the cost of the ICP; however, funding mechanisms for implementing the pro-
gram will be determined by the agencies in the design phase of the remedial action
process.
Tbe ICP must be implemented concurrently with the residential soils remedial action
because lack of such controls could jeopardize the effectiveness of the selected remedy.
The ROD outlines the components of an ICP for residential soils (i.e.. a comprehensive
management program to include permitting. community education, and soils services).
but the actual implementation of the program will require at least the adoption of local
ordinances, setting up an administrative system to oversee and run the program, and
documentation of detailed procedures for each of the program components. This
implementation phase has been referred to as "Phase II" (see page 1-3 of An Evaluation.
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of Institutional Controls for the Populated Areas of the Bunker Hill Superfund Site) and
will involve a high degree of community panicipation.
In addition, the proteCtiveness of yard soil barriers is dependent on the success of the
rcp, and the ICP will only be successful if it is not unduly burdensome, confusing, andl
or restriCtive for property owners and local government. The agencies believe that a
lengthy period of essentially trial and error experience prior to developing final pro-
gram elementS would create unnecessary confusion and frustration.
Since contamination will be left in place with respeCt to the remedy described in the
Residential Soils ROD, the agencies will periodically review the residential soils aCtion
to ensure its proteCtiveness. Pan of this review will focus on the ICP and itS effeCtive-
ness. If the rcp is determined to be inappropriate, changes to the program can be
made through the review process.
The agencies agree that it is not necessary for a public entity to provide these services;
however, it is essential that such services are perpetually integrated into the overall rcp.
Implementation, funding, and work required by the ICP for residential soils will be the
subject of RDIRA and consent decree negotiations berween the agencies and responsi- .
ble panies.
COMMENT V. Miscellaneous Other Comments
Comment V.A.: "FS Table E.l (p. ES-4) sets fonh a summary of estimated present wonh costS of the
remedial alternatives evaluated in the FS. As itS footnote 2 indicates, however, that analysis does not
include re-remediation of 221 residential yards addressed during prior summer aCtivities. Commenters
suppon the conclusion, implicit in the analysis underlying this chan, that regardless of the remedial
approach adopted for residential yards that have not yet been subject to removal activities, there is no
basis for EP A to require re-remediation of soils which previously have been excavated in prior removal
actions. Among other faCtors, the community impaCtS that would be associated with such reexcavation
aCtivities simply cannot be justified..
Response:
The purpose of the footnote in Table E.l is for informational purposes only. By not
considering the already remediated propenies in the cost estimates for each alternative,
the same number of homes for potential remedial aCtion is consistent from alternative
to alternative.
The footnote does not in any way indicate a decision by the agencies to eliminate these
homes from consideration of re-remediation. However, the selected remedy is
consistent with the method in which these yards were addressed and the agencies do not
intend to redo this work. If those propenies become recontaminated in the future, they
will be considered for re-remediation.
Comment V.B.: "The background information presented in Chapter 1 of the FS contains several errors
of fact. The nonpopulated areas FS, referred to at page 1-1, is being conduCted by Gulf Resources and
Chemical Corporation and Pindar Corporation, not Gulf Resources, Ine. 'Other nonpopulated areas
activities are being co-sponsored by Gulf and others."
Response:
Comment noted.
Comment V.C.: "In discussing the history of the site the FS incorrectly states that "for most of its oper-
ating life, the Bunker Hill complex had few or no controls on atmospheric emissions, solid waste
-------
disposal. or waste water treatmenL" FS at p. 1-17. This is incorrect. A variety of pollution control
devices were installed over the years. For example. tailings were impounded at the Bunker Hill complex
beginning in 1928 and atmospheric emission controls were put in place from the time the processin
facilities were constructed in 1917 and repeatedly improved over the years. Further, the paragraph OD
page 1-18 characterizing the effectS of the 1973 "baghouse fire" prejudicially states disputed factS and
conclusions that have no bearing on the FS: To avoid inaccuracy, this entire section should be deleted."
Response:
Comment noted.
Comment V.D.: "The FS says that the current primary contaminant migration mechanism is airborne
deposition of contaminated dust from fugitive dust sources "in and adjacent to the mining/smelting
complex." Commenters agree that major dust sources are the properties owned by the Bunker Limited
Partnership and its affiliated entities."
Response:
Comment noted.
Comment V.Eo; °FS Figure 1-5 purports to show general residential soil remediation pathways. Among
those portrayed is an upward movement of metals. apparently from groundwater. In light of the FS's
discounting of concerns for capillary action. and the data set forth in the McCulley, Frick & Gilman. Ine.
memorandum at~ched as Exhibit C to these commentS, those arrows should be eliminated. There also
would appear to be no basis to include an arrow from the South Fork of the Coeur d'Alene River."
Response:
The arrows in the referenced figure were placed to indicate potential pathways of
migration to residential soiL Since the FS discounts the effect of capillary action on
soil recontamination. the arrow was shaded to indicate that it is not a significant path-
way. For funher infonnation. please see the response to Exhibit C comments.
The agencies believe that flooding and consequent deposition of solids from the Sout
Fork of the Coeur d' Alene River is a potential source of recontamination and the
arrow was appropriately placed on the figure.
Comment V.F.: TS Table 2-1 sets forth Federal chemical-specific ARARs. It states that .5 ~g/dl of
lead per cubic meter of air is a proposed standard. This is incorrect. No such standard has been
proposed nor, in the expectation of the Commenters, is likely to be proposed."
Response:
See "U.s. EPA. Report o{ the Clean Air Sc~ntific Advisory Commiltee on iLr Review o{
tM National Ambient Air QuaJily Standard.s {or Lead", EPA-SAB-EC90-001. December
1989.
Please note that the comment should use the units of ~g Pb/m3.
Comment V.G.: "FS Table 2-1 also describes among To Be Considered (~Cj materials EPA's strategy
document for reducing lead exposure. That document is not properly a TBC documenL Rather, it is a
document describing how EP A intends to implement various future rule-making aCtivities. It has no
independent scientific or regulatory importance.."
Response:
U.s. EP A and IDHW are ronsidering this document a TBC for this site.
Comment V.H.: "At p. 6-23, the FS states that risks to human health and the environment would be
likely to increase over time if left unmitigated. This is questionable. It is more likely that renewed
groWth of vegetation in the area would gradually mitigate the amount of contaminated dust and soil
transported by winds and erosion. Replacement of residential site soils per se is going to have a very
-------
limited effect as far as containing contaminated soil and dust from high winds and surface water runoff
from the Superfund .site."
Response:
The statement as found in the FS (p. 6-33) is accurate. Continued transport of highly
contaminated solids by both water and wind erosion to residential areas results in
unneressary and excess exposures to the community. Monitoring and modeling results
presented in the RADER have shown that rates of lead deposition in some pans of the
residential areas (up to 1 lb/acrelyr) have resulted in the accumulation of approximately
100 ppmlyr for lead in litter. Within the residential areas, yard soil concentrations for
lead range from 53 to 17,800 ppm (1.78 percent Pb in soil). Any transport of highly
contaminated solids within the site would result in an increase of community exposures
and consequent health effects.
Mobilization of highly contaminated soils also increases its hazard potential since it is
likely to be converted or introduced to media exhibiting high community exposure fre-
quency, such as house dust. Soil transport and incorporation to house dusts is a major
concern at the site since small soil particles exhibiting high metals content accumulate
as dusts in homes and present high contact potential to sensitive populations. Any
deterioration of current site conditions or reduction of effort towards mitigation or
health intervention are likely to result in increased health risk to the community. The
prospective for continued success of the Lead Health Intervention Program is n~t
assured. Childhood blood lead levels at the site are doubtless reduced as a result of the
aggressive monitoring and follow-up program currently instituted. It is doubtful that
the 90+ percent level of participation exhibited by the community could be continued
indefinitely. Those children currently protected by the program could be at great risk if
the program were compromised.
Comment V.I.: "Re: Proposed Plan, p. 5: What is the explanation for the fact that children in Page
have a blood leadiverage above 10 ~g/dl Pb, whereas children in Smelterville, Kellogg, and Wardner
average less than 10 ~g/dl Pb, even though soil lead levels in those communities are double or triple the
levels found in Page? Does this not suggest that there may be an entirely different source involved
rather than lead in soil? Also, does it not raise a serious doubt as to the rationality of the 1,000 ~g/g
Pb [ppm lead) criteria?8
Response:
Page and Pinehurst blood lead responses are approximately equivalent to those ob-
served in other studies, and it is the response in Smelterville, Kellogg, and Wardner
that is considered atypical. There is greater uncertainty that the 1,000 ppm soil lead
cleanup threshold is protective in Page and Pinehurst than for the remainder of the
site. Children in some portions of the residential community tend to exhibit mean
blood lead responses to contaminated soils and dusts greater than the overall
community mean. Children in Page and Pinehurst exhibit mean soil/dust lead dose
coemcienu that are approximately twice those observed in Smelterville, Kellogg, and
Wardner. These higher soil/dust lead dose coefficients are typical of a more "common"
response that has been observed at East Helena, Montana, and simi1ar to the response
described in version 4.0 of u.S. EP A's Integrated UptakelBiokinetic (IUBK) Dose-
Response Lead Model (LEAD4) using default input parameters. Site-specific factors
that control physiologic response to environmental lead exposures and "effective" lead
absorption are:
1.
Site climate and meteorological conditions
2.
Contaminated dust loadings
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3.
Form and chemical species of lead-a>ntaminated solids (issues related to the
relative proponions of ore, slag, tailings, concentrate, and lead oxide dustS that
comprise contaminated solids)
~.
Presence of other associated metals competing with lead absorption (physio-
logic absorption)
5.
Total daily lead intake (lead absorption rate is dependent on intake rates; high
daily intakes can result in lower GIT absorption coefficientS)
6.
General population socioeconomic and nutritional status
7.
An effective exposure and health intervention program that potentially reduces
total soil intake and subsequent absorption through awareness, hygiene, and
nutrition programs
Those specific factors that could yield an increase in the total absorption of lead in
Page and Pinehurst relative to the rest of the community are related to factors 3, ~, 5,
and 7. Reduced lead absorption (in lower response areas) could be a result of propor-
tionately higher levels of ore, slag, and tailings comprising contaminated soUds in the
flood plain of the South Fork of the Coeur d' Alene River. Considerably higher con-
cenU'3tions of lead and other metals are found in Smelterville, Kellogg, and Wardner
soils and dustS, which yields a lower GIT (gastrointestinal tract) absorption rate for lead
in the three towns. Also. less community health intervention has been practiced in
Page and Pinehurst, while considerably more effon has gone towards exposure interven-
tion and education in Smeltemlle, Kellogg, and Wardner, again yielding a lower uptake
rate (either as soiVdust ingestion of lead absorption rate, or both) for lead in the three
towns. Anyone or all of these factors in combination would yield an apparent (rei-
tive) increase in the rate of lead uptake in Page and Pinehurst.
Observed ditTerences in physiologic response to environmental lead exposures, quanti-
fied in terms of. tbe soiVdust lead dose coefficient, betWeen SmeltemllelKelloggt
Wardner and PagelPinehurst suggest that post-remedial physiologic response in
Smelterville, Kellogg, and Wardner could approach the .common. response (as defined
above). A reduction of total metals exposures and the cessation of the community
Health Intervention Programin Smeltemlle, Kellogg, and Wardner could result in an
increase in the soiVdust lead dose coefficient to those values observed in Page,
Pinehurst, and East Helena (Montana).
Comment V.J.: ~e: Proposed Plan. p. 6: Sources of contamination to residential soil other than tail-
ings and airborne smelter emissions are not addressed. Other possible sources are windblown deposition
of dust from the mining-smelter complex; exhaust emissions from internal combustion engines; lead-
based paint; lead piping and lead solder in water piping; and use of smelter slag, both as a traction agent
and soil modifier..
Response:
The administrative record, specifically the Protocol Document and RADER, have com-
pared offsite background environmental contaminant levels for all exposure media to
onsite levels. An evaluation of health risk associated with environmental contamination
found onsite for seven metals of concern in various exposure media are summarized in
Tables 7.22 through.7.26 of the Protocol Document. Chronic lead intakes, for example,
are estimated ro be 2.1 ro 7.7 rimes greater onsite than for an offsite population. The
RADER identifies those sources and mechanisms responsible for environmental media
contamination in the residential areas. E.'Chaust emissions from internal combustion
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engines, lead-based paint. lead piping, and lead solder in water piping are considered
small contributors to the total lead uptake for members of the residential populations
at the Bunker llill site.
Comment V.K.: "Re: Proposed Plan, p. 5. The phrase "To ensure protection from adverse health ef-
fects associated with exposure to lead, EP A and IDHW has determined that it is necessary to clean up
any residential property within the Bunker llill site with a lead concentration of'l,OOO parts per
million.", seems to express an unjustified level of confidence that soil replacement will eliminate all
blood lead problems, especially when the cause of the problems may not be fully defined."
Response:
Remediation of contaminated soils in the residential areas of the site is one component
of a comprehensive plan to reduce sensitive populations' exposure to metals. House
dusts, fugitive dust sources, air, surface and ground water, materials and waste piles, ete.
wiIl also be addressed in the comprehensive plan. The agencies are confident that all
contaminant sources and media of health significance have been characterized during RI
activities and appropriate remediation will occur as part of the final plan. If the
commenters believe that any exposure routes and/or media have been overlooked, they
should have been identified during remedial investigations. Identification of additional
concerns should be made at this time. Any media or transport processes that still
require remediation following implementation of the final plan should be detected dur-
ing followup site monitoring and health surveys.
Comment V.L: "Re: Proposed Plan, p. 9. The difficulty and the prospect of serious structural damage
under Alternative6 is underemphasized. Considering the condition of many of the structures in the
Superfund Site, removal of surrounding soil to a 7-inch depth could prove disastrous:
Response:
Although it is feasible to remediate to a depth of 7 feet, the agencies agree that the
difficulty and cost of such a program would be extreme. Therefore, Alternative 6 has
not been selected. (The agencies believe the comment should have stated "7-foot"
rather than "7-inch-depth".)
Comment V.M.: "Re: Proposed Plan, pp. 7 and 10: It should be emphasized that "garden areas" refers
to vegetable and fruit gardens and ~ flower gardens.
Response:
Comment noted. Garden areas are referred to as "produce gardens" in the Record of
Decision for the Residential Soil Operable Unit.
E.XHffilT A: Comments on EPA's Proposed Cleanup Goals ror the Populated Areas or the Bunker Hill
Site
Responses to the comments presented in this exhibit have been addressed in the responses to
Comment II.
EXHIBIT B: Residential Soil Sample Variations; Exhibit "B" of the document submitted by the PRPs
during the public comment period discusses the differences between results obtained by IDHWIU.S.
EP A. using a modified laboratory analytical technique for metals analysis, and a nonmodified technique,
as used by a representative of the PRPs, American Energy and Environment (AEEE). The difference
betWeen the tWo techniques is that for the modified technique the sample is dried and then sieved
through an SO-mesh screen. Only the portion passing the 8O-mesh screen is analyzed. The nonmodified
technique does not dry the sample and does not sieve the sample before analysis.
-------
AEEE rompared the 0- to I-inch sample analysis results for samples rollected in May 1991 using the
two techniques. It \Ifd.S found that the modified technique had lead ron~ntrations approximately
1.5 times higher than the non modified technique.
To further evaluate this differen~, AEEE had nine samples analyzed that w~re taken from anOther sam-
pling event, ronducted by the PRPs, using both techniques. The results of these analyses did not indi-
clte a bias between the techniques. AEEE roncluded that the analytical techniques themselves (i.e., the
sieving of the sample) were not responsible for the bias in the Mt set of data. It \Ifd.S assumed that the
sample rollection or sample preparation were responsible for the high bias of the modified technique
that was employed by IDHWIU.S. EPA
Several romments were provided by the PRPs as to the actual c:l11Se of the bias.
Comment 1: The samples were gathered by CH1~ HILL and split in the field. The moisture rontent,
soil ronsistency, and the technidans' splitting technique rould all rontribute to an uneven splitting of the
solid sample.
Response:
All soil samples roUected in May 1991 were split in the field following the techniques
specified in .F~ld Sampling Plan (FSP) [or the Phase II RI Sampling and Analysis Plan
/Jwtk.u Hill CERCLA Sile Populaud Artas RIfFS Document No. BHPA-FSP89-F.RO-
050489.. The soil samples obtained in May 1991 were not overly wet, and adequate
mixing \Ifd.S performed prior to splitting to ensure that the two portions of the sample
were homogeneous.
It is also unclear how an unbiased sampling error (i.e., inromplete mixing or uneven
splitting) would result in a biased analytic:1l result (i.e., all of the' IDHWIU.S. EP A
samples being higher than the AEEE results).
Comment 2: [It was] noted on a visual inspection of the soil samples in the soil sample rollection bags
that there were some samples that had not been well mixed. (See Attachment C to Exhibit B.) This
would make it more difficult to obtain a representative sample for digestion.
Response:
All samples taken during May 1991 were completely broken up and romposited as re-
quired in the previously referenced FSP. Based on the information rontained in the
romment. it is unclear what samples were observed.
Again, it is not clear how these actions, even if they were done, rould lead to the biased
results observed betWeen tbe tWo analytical techniques.
Comment 3: The modified CLP788 procedure includes a drying step in which the sample is dried at
60 degrees C. overnight. and then screened through a -80 mesh screen. Variabilities could arise in this
step due to differences in screening technique. [It was] noticed that tWo different technicians performing
the screening step on similar soil samples resulted in very different final samples that would be used for
analysis. One of the technic1an's meshing and screening step resulted in about 7S percent of the soil
remaining in the plus 80 fraction that is archived and not analyzed. and tbe remaining 2S per~nt of the
sample was then used for analysis. The other technician, by comparison, screened a similar sample and
all of the soil went into the minus 80 fraction used for analysis.
Response:
Eleven (11) AEEE samples rontaining the +80 fraction were seleCted at random and
sieved through an 80 mesh .screen. The mean of -80 remaining in these samples was
1.38 percent The standard deviation of -80 remaining was 1.08 percent. At the 95 per-
cent ronfiden~ interval, this equates to a maximum intersample variation of
-------
2.16 percenL While not insignificant, these figures represent a relatively minor source
of method intersample variation.
Comment 4: Variabilities could have arisen by cross contamination. The screening process included a
cleaning step in which the screen '[i]s cleaned by blowing compressed air over iL It was noted that the
. technician used inconsistent and careless cleaning in this step.
Response:
Considering the volume of sample containing most AEEE samples and the high lead
concentrations in these samples, any cross contamination due to micron-size particles
(i.e., dust) being left on the screen after blowing off with high pressure air would be
unmeasurable or insignificant at besL
Comment 5: There was a possibility of cross contamination in the digestion procedure also. It was
observed that in bulking the samples to their final 200 ml volume, the same graduated cylinder was used
without careful rinsing betWeen samples.
Response:
Silver Valley Laboratories' (SVL) procedure is to rinse graduated cylinders three (3)
times with deionized water betWeen samples during the digestate bulking process. This
procedure was followed for the AEEE samples.
Comment 6: The possibility of error also exists in the data generation. In the reporting of the data
there is a step that incorporates a percent solids test to correct for the moisture fraction found in the
soils that have not been dried. This percent solids value was calculated in the standard CLP788 method
utilized by AEEE. It was noted that this test was also applied to the IDHW/EPA modified CLP788
method. If inadvertently the percent solids were used to calculated the final results of the IDHW/EP A
samples it would lead to an error comparable to what [is] seen in Table 1, columns 3 and 4.
Response:
Four IDHW data packages selected at random were reviewed. The modified CLP
method followed by SVL for the IDHW did not include a percent solids adjustment of
the final results. Samples were dried and sieved before analysis; therefore, no percent
solids correction was necessary.
Summary Comment: Based on these results, EP A should evaluate variability in data from their past and
current sample collection and analysis procedures. Based on their reevaluation, EP A/IDHW may wish
to reanalyze some or all yards.
Response:
The agencies believe that the above responses adequately address any concerns regard-
ing data variability and there is no need to reevaluate the data base or reanalyze some
or aU yard samples.
EXHIBIT C: Review of EPA Study on Upward Movement or Lead in Yard Soils; "The conclusions in
Appendix B (of the Residential Soil Feasibility Study) clearly state that there is little empirical evidence
to suggest that upward migration of lead is occurring on site in residential soil. ...there are compelling
hydrologic and chemical precepts that indicate that such upward migration is not expected to be a
significant process in the past, present or future. Consequently, we see no utility or justification for the
specification of a capillarity barrier for yard remediation."
Response:
The CERCLA process requires that the agencies "seleCt a remedial action that is pro-
tective of human health and the environment, that is cost-effective, and that utilizes
permanent solutions" (emphasis added) "and alternative treatment technologies or
-------
resource recovery technologies to the maximum extent practicable."l Upward migra-
tion of inorg:mics is a documented phenomenon and. therefore. a potential migratio
pathway that, if not evaluated and considered. could adversely affect the permanence
the selected remedial alternative.
Appendix B of the Residential Soils Focused Feasibility Study is a worst-<:3Se evaluation
of the potential for upward migration. The conclusions of the appendix agree with the
basic comment above in that "there is no empirical evidence to suggest that lead upward
migration is occurring onsite in residential soils."
SUMMARY OF SPECIFIC CO~~fENTS
Comment 1: "The modeling approach does not consider the effects of recharge. which wou.Id transport
water down~'3rd... AdditionaUy. the author [of the upward migration techniClI memorandumj cites the
occurrence of Clliche layers as evidence of upward flow from a sballow water table. We did not find any
notation of Clliche layers in the RIiFS boring logs."
Response:
Indeed the modeling approach does not consider the ~ffects of recharge. This provides
a more conservative estimate of the potential for upward migration of contaminantS.
The summary section of the appendix explains that "the objective was to perform a
worst-case analysis using a simplified model..
The introductory sentence of the technical memorandum states that the existence of
"Clliche" or "hardpan" layers are evidence of the upward flow of inorganic constituentS
througb the soil profile. This introductory sentence presentS the idea of upward migra-
tion to the reader who may not be familiar with soil chemistry. It is presumed that
Clliche or hardpan layers are a familiar occurrence to most readers of the documen
The absence of these layetS does not dismiss tbe occurrence of the phenomenon. Th
memorandum does not state that tbere are calicbe or hardpan layers at the Bunker Hill
Superfund site.
Comment 2: "The stratigraphy betWeen ground surface and the water table is known to be heteroge-
neous, not homogeneous as assumed in tbe report. Stratified layers.- represent textural discontinuities
that would bave profound in11uence on the vertiClI migration of soil water."
Comment 3: "The modeling process considers only evaporation not evapotranspiration. ...the
assumption tbat solutes will accumulate only in tbe upper 1 inch as a result of evaporation is
unfounded. .
Comment 4: -'The range of pH values assumed for ground water are about one pH unit lower than the
actual range rypiCllly measured in water from the RIJFS wells. The system is not as acidic as assumed.
which affeCtS the speciation and mobility of lead.
Comment 5: "...the modeling assumption that concentrations in soil water are equal to the observed
concentrations in ground water bas not been honored."
Comment 6: "The correlation of soil water Pb concentrations to distribution coefficientS and measured
soil Pb concentrations probably does not accurately represent a soil water system with significant Pb
lCumprehensive Environmenral Response. Compensation. and Liability Act of 1980.
S~ction 1:1(b)(1).
-------
controls exerted by precipitation of sparingly soluble Pb compounds.... ...will probably overestimate the
aqueous lead in the subsurface..
Comment 7: "The rates of lead accumulation in the surficial soils depicted in Figures 4, 5, and 6 [from
the upward migration technical memorandum] assume that the lead concentrations in soil water are
accurate and that all of the dissolved lead will migrate to the upper one inch of soil,... ...such
assumptions are not valid...."
Response to Comments 2 through 7: Each of these comments concerns the validity of the assumptions
made for modeling the upward migration of lead in residential soil. The assumptions
were made to produce a worst-case estimate of the upward migration of contaminants
to the upper one inch of soiL The memorandum clearly states these assumptions and
indicates that this is a simplified modeling effort based on worst-case assumptions.
EXHIBIT D: Depth or Contamination in Residential Yards, Bunker HiD Superfund Site; "This
alternative [Alternative 3] is internally inconsistent because lead contamination does not exist to depths
of at least 12 inch~ in al1 residential areas. Chemical data documenting the decrease in concentration
of contaminants with depth include tWo different sets of data collected by the PRPs during 1990."
"A core sampling program could determine the vertical profile of lead concentration, and allow the
remediation effort at an individual residence to concern only those soil intervals that threaten human
health."
Response:
The agencies agree that a core sampling program could determine the vertical profile of
lead concentration and a sampling program is being required as part of this ROD. As
stated earlier, if contamination above the threshold level does not exist below 6 inches.
a 6-inch excavation will be acceptable.
3.3 SUMMARY OF INSTITUTIONAL CONTROLS MEETINGS
The purpose of this section of the Responsiveness Summary is to describe local government and commu- .
nity involvement in the development of the Institutional Controls Program (ICP) and to respond to
comments raised by local officials during the comment period.
The agencies understand that the success of an ICP is dependent on the communities' and local govern-
ments' involvement and support. Development of the ICP occurred over a 4-year period. Information
was gathered and concerns were defined through many meetings, presentations, and discussions with
local government and citizen representatives. Comments and concerns associated with an ICP were
solicited both before and after the report entitled An Evaluation of Institutional Controls for the Popu-
lated Areas of tM Bunker J1z1J Superfund Sire was completed.
3.3.1 MEETINGS HELD PRIOR TO REPORT COMPLETION
During development of the ICP report, the agencies met with the Task Force (public meeting), local
government officials (both elected and appointed representatives of affected cities and the county), and
other interested groups. Comments received during these- discussions were particularly important in
determining the scope of a locally acceptable ICP.
The preevaluation meetings focused on conceptual development of an ICP that could operate within the
context of current authorities. In general, the response was favorable with the following provisions:
-------
1.
Institutional controls should minimize inconvenience and loss of land use options to local gov-
ernments and residents.
2.
Institutional controls should use, to the maximum extent practicable, existing contro
mechanisms and 10ClI agencies.
3.
Institutional controls should be self-sustaining and impose no additional cost on local govern-
ments, residents. or property owners.
These concerns were usedas guidelines in producing the Draft Evaluation of Institutional Controls for th~
Populated Areas of rhe Bunker Hill Superfund SiJe..
3..3.2 ~IEETINGS fIELD AFTER REPORT COMPLETION
The evaluation document was CQmpleted in January 1991 and mailed to elected officials in all the cities
wjthin the Superfund site as well as Shoshone County. It was also available for public comment from
April 29 through June 30. 1991. and was described as part of the Proposed Plan. Following the mailing,
meetings were held in ~1arcl1 through May 1991 to discuss the document with elected officials from the
cities and county. the Task Force (public meeting). and other interested or potentially affected parties.
Concerns and questions noted at those meetings and the agencies' responses follow. Comments and
responses have been organized by subject for clarity.
rMPLDIENTA no N~L\."" AG E.\IENT
Comment: One CQmmenter was concerned about being sure everyone who needed to. adhered to
program requirements.
Response:
The ICP wjll be presented in a positive manner, to be used by tile homeowner durir.
land tral\S4ctions. A high level of CQmmunity awareness and education wjll be main--
tained and, if all else fails. the penalties ,assodated witl1 breaking local laws and ordi-
nances would be invoked.
Comment: Another commenter requested that proposed deed notices serve as an educational tool and
not as a restriction to land use.
Response:
Deed notices are intended to notify potential purcl1a.sers of real estate about the condi-
tion of the property being considered. It is not anticipated that these notices wjU
restrict land use; rather, tl1ey are informational in nature.
Comment: A CQmmenter from Pinel1urst wanted to know if the ICP was going to be instituted in
Pinehurst.
Response:
Some or all of the ICP elements will be utilized in Pinehurst depending upon the extent
of remediation and the amount of contamination that remains in yards after the
cleanup has been completed.
Comment: Several commenters representing the various cities were not interested in providing project
management and emphasized that the cities do not have the funds to ensure perpetual management of
an ICP.
-------
Response:
The agencies have considered this comment and do not anticipate that tbe cities will be
required to fund or manage tbe program in perpetuity. Funding for the program as
well as the management of the program will be determined as part of the design of this
remedial action.
Comment: When would the cities be asked to "sign-on" to tbe program?
Response:
Development of the ICP has followed the public comment period on the proposed plan.
Tbe cities will be asked to "sign-on" prior to initiation of remedial design for the
residential soils action.
Comment: The City of Wardner is currently rewriting its comprehensive plan and zoning ordinances and
wanted to know if they needed to factor in the proposed ICP.
Response:
It is suggested that the city stay in contact with the agencies developing the ICP in
order to incorporate as much information from the ICP as possible. It was also noted
that if portions of the ICP developed at a later date would require amendments to city
plans, assistance would be provided.
Comment: How enforceable is the ICP?
Response:
The ICP is expected to be incorporated into city and county ordinances and regulations
that have the weight of law.
Comment: What would be done with partially remediated yards?
Response:
There will be no partially remediated yards. If sampling and analysis indicates soil
concentrations exceeding 1,000 ppm lead, the entire yard will be remediated.
Comment: What would be required of a homeowner whose paved/driveway deteriorated to the point
that it would need to be replaced?
Response:
The bomeowner would have a variety of options under the proposed ICP. Included in
those options would be repaving or replacement and capping if soil lead levels war-
ranted it.
Comment: Would the ICP be in conflict with Federal Aood Plain Ordinances?
Response:
Tbe ICP and Aood Plain Ordinances will not be in conflict.
PUBUC INVOLVEMENT
Comment: One commenter wanted to know what would happen if, after the ICP was designed and
approved by local elected officials, the public did not like it.
Response:
The plan was subject to public comment for 60 days. The agencies did not receive
adverse comments from members of the community. The concerns raised during the
comment period .came primarily from the PRPs (see Section II of the Responsiveness
Summary). Ongoing public education regarding the institutional controls program is
integral to the program's success.
Comment: Why should Pinehurst have to participate in the ICP?
-------
Response:
COSTfFUNDING
The ICP is needed in Pinehurst to ensure barrier maintenance. The ICP will apply to
all residential properties within the site.
~
,
Comment: One oommenter requested additional information on the oost of administering the ICP.
Response:
The cost estimates for the ICP are included in both An Evaluation of InstirutionoJ Con-
trols for lM Populared Areas of lM BunJco Hill Superjund Site and the ReswenriaJ Soil
Feasibility StUdy.
Comment: How will the YCP be funded?
Response:
Funding of the ICP will be determined during remedial design.
D EVELO P\ fE;o..i!D ISllJRBA. ~CES
Comment: One oommenter wanted to know if realtors should be .digging in. sales signs.
Response:
It was suggested that for now. small signs that negate the need for deep holes should be
used.
Comment: Using the ICP to facilitate land transactions and future development made the program
worthwhile.
Response:
Comment noted.
Comment: How would someone go about developing a lot? And. if soil testing was necessary. wH
would pay for it?
Response:
There are currently no special Superfund requirements for property development. but
anyone wishing to begin a project should oontact the Kellogg Superfund Project Office
for information. Mechanisms for addressing property development with respect to oon-
tamination outside the residential areas will be addressed in the Non-populated Areas
R IJFS.
Comment: What would be done for homeowners wanting to put in a vegetable garden?
Response:
PERMITS
People wishing to grow produce gardens should do so in 24 inches of cle~m soil. For
those homes exceeding the threshold level and requiring remediatioD. 24 inches of clean
material will be provided during cleanup. For others whose yards are not cleaned up.
clean soil will be made available for developing produce garden areas.
Comment: One oommenter wanted to know if homeowners would be charged for permits associated
with the ICP.
Response:
Funding mechanisms for the program will be determined as pan of the design of the
remedial action. but it is anticipated that homeowners will not be required to pay for
permits.
-------
Comment: Where would a homeowner go to obtain a permit to dig? Could they be obtained over the
phone?
Response:
While the complete program has not been developed, permits would most likely be
available at each city hall through an existing governmental department such as the
Building Department or the Department of Public Works. Permit availability win be
determined in remedial design.
Comment: The ICP appeared to be fairly aggressive in requiring permits and managing barriers and, as
proposed, it provides a complete approach to the challenge of managing barriers and future
development.
Response:
Comment noted.
Comment: Another concern was in regard to how the decision win be made as to what is hazardous and
what soil cleanup level would be used.
Response:
A soil lead concentration of 1,000 ppm is the threshold level for cleanup of residential
surficial soils. Procedures for determining soil concentrations below clean barriers will
be developed during remedial design.
Comment: How did Pinehurst end up in the Superfund site, if no elevated blood lead levels were noted
in Pinehurst children? What were the soil lead levels in Pinehurst?
Response:
Sampling and analysis indicate some soil lead levels throughout the city exceed the
threshold level of 1,000 ppm lead and approximately 30 percent of the children tested
have blood lead concentrations greater than 10 I!g/dl. Soil lead concentrations varied
between approximately 60 and 8,000 ppm with an average of 460 ppm.
Comment: Has any thought been given to controlling movement of metals up or down through the soil
column?
Response:
Yes, a discussion of this issue is presented as part of the feasibility study for residential
soil. It was detertnined that the probability of this mechanism affecting remediation at
this site is very low. .
Comment: What is a barrier and will different types of barriers be used at the Bunker site?
Response:
In general, a barrier is a physical cap or layer of materials that prevents exposure of
people to contaminants beneath the barrier. Different types of barriers may be used at
the site, depending on differing land uses. The barrier required for residential soil is
determined in this ROD. The specific type of barriers required for other types of land
use will be determined as part of other cleanup decisions.
Comment: Are institutional controls being considered at other Superfund sites?
Response:
Yes, institutional controls are being considered at other Superfund sites both for resi-
dential and other uses.
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Table 2
Public Meeting5 Summary
Residential Soils Operable Unit
I Bunker Hill Superfund Site
Page 1 of 6
Date Description (Subjects Discussed)
~fay 23. 1991 Proposed Plan: Residential Soils Oe3nup Public Comment Meeting
Other Sitewide Activities
I February 21. 1991 Status Report on Residential Soil Fe3Sibility Study
Institutional Controls Program
i Status of PRP Sitewide CIe3nup Proposal
,
I October 25. 1990 Update on Hillside Revegetation Order
i Results of 1990 Blood Lead Screening
I Risk Assessment Data Evaluation Report Summary and Conclusion
Agency for Toxic Substance and Disease Registry (ATSDR) Response to
Task Forcel1DHW Questions on Lead He3ltb Issues
July 19. 1990 Risk Assessment Data Evaluation Report
Smelter Order/Plans
Fugitive Dust Event Air Monito~
Update on 1990 Residential Soil Removal Program
. A TSDR Answe~ to Task Force P..e3lth Questions
1990 Blood Lc3d Screening Program
April 12. 1990 Negotiations with PRPs
Smelter CompleX/Unilateral Order
Page PondlResidential Soil Disposal
1990 Residential Soil Removal
Homeowner Meetings
Contractor Workshops
Emergency Removal '15. Remedial
Interior House Dust
Update on 1989 Blood Lead Screening
November 16. 1989 Status Report on Bunker Complex
U.S. EPA Order
Buried Waste
Status Repon on 1989 Residential Soil Removal
Report on August 1989 Lead Screening
Update on Interior House Dust
Miscellaneous Topics
U.S. EPAlIDHW-PRP Negotiations
Slag
December Fact Sheet
Technical Assistance Grant
August 2~. 1989 Update on Negotiations
Status Report on Soil Removal Project
Discussion of Slag Issue
Update on Fugitive Dust
Status Report on August Lead Screening
~fay 18. 1989 Discussion of Community Comments on Proposed Removal Activities
-------
Date
February 16, 1989
December 15. 1988
October 19, 1988
September 8, 1988
July 28, 1988
June 30, 1988
Table 2
Public Meetings Summary
Residential Soils Operable Unit
Bunker Hill Superfund Site
Page 2 of 6
Description (Subjects Discussed)
Status on Negotiations with Gulf Resources & Chemical Corporation
Update on Activities on Non-populated Areas of the Site
Update on Health Issues
Summer 1989 C1eanup
Plans for C1eanup
Schedules
Update on Populated Remedial Investigations
Update on Non-populated Remedial Investigation
Negotiations with Gulf Resources & ChemiClI Corporation
Status of 1989 Removal Plans
Why Do We Need a C1eanup
Health Risk
Summary: 1988 Health Intervention Program
Gctting to Cleanup
Homeowners Letter
Explanation of Letter
Maps
Summer 1989 Cleanup
Selecting Properties
C1eanup Alternatives
Continued Discussion of Health Issues
Introduction to Risk Assessment
Pathways
Health Criteria
C1eanup Limits
Overview of Historic Lead Health Issues
Environmental Toxicology
Health Effects of Local Contaminants
1988 Summer Lead Screening
IDHW
Final RUFS Work Plan (Populated Areas)
1988 Summer Sampling Events
Status on Previous Sampling and Analysis
U.S. EP A
Status on Gulf RUFS Oversight
Status on Gulf Focused Feasibility Studies
Status on Gulf FOIA Request
GulCIPintlar
Status on RUFS Activities on Non-populated Areas
Technical Assistance Grant Update
Introduction to U.S. EP A Health Risk Assessment Process
Endangerment Assessment
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Table 2
Public Meetings Summary
ResidentiaJ Soils Operable Unit
Bunker Hill Superfund Site
Page J or 6
Date Description (Subjects Discussed)
May 12. 1988 Introduction: Activities in the Past 6 Months
Project Overview
Project Status
Gulf/Pintlar
, U.S. EPA
! IDHW
i Introduction to Endangerment
I Upcoming Activities
December 10. 1987 Populated Are:lS
Progress in 1987
Future Activities
Non-populated Are:lS
Progress Status
Update of Gulf Activities
Oversight Activities
Contractor Transition
Fe:lSibiliry Studies
Future Activities
August 13. 1987 Upcoming Non-populated Are:lS-RIfFS Field Activities
19~ Residential Soil Sampling ResultS
Review Outline (or RIfFS Work Plan (or Populated Areas
June 18. 1987 Status of U.S. EP A Activities
Gulf Resources Involvement
Field Activities in Non-populated Areas
U.S. EP A Oversight
Status of Slate of Idaho Activities
Progress to Date
Project Plan
Silver Valley Laboratories
April 16. 1987 RJJFS in Non-populated Areas
Gulf Resources Involvement
Work Plan
Proposed Consent Order
Schedule
Windblown Dust
State Activities
U.S. EP A Activities
Schedule
RIfFS Study in Populated Areas
March 9. 1987 Status of Gulf Involvement in RIfFS Activities
Status of IDHW Activities
Contractor Selection
Cooperative Agreement I
Silver Valley Llboratories
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Table 2
Public Meetings Summary
Residential Soils Operable Unit
Bunker Hill Superfund Site
Page" of 6
Date Description (Subjects Discussed)
February 5, 1987 Orientation of Work Plan to Potential Remedies
Schedule
Tasks 1 through 10, Feasibility Study, and Proposal
December 11, 1986 Rea uthorization/Su perfund
Site Characterization Repon
Gulf Involvement in RIIFS
Fall Sampling Activities
Residential Soil Sampling
Windblown Dust Monitoring Program
Project Schedule
Shon-Term Remedies
RIfFS
September 18, 1986 Update on 1986 Blood Lead Screening
Status Repon on Residential Soil Sampling
Status Repon on Fugitive DUst Monitoring Program
RIfFS Status
Schedule
Reauthorization of Superfund
Involvement of Gulf Resources
Site Characterization Repon
August 7, 1986 Status Repon of Blood Lead Screening
Fast-Track Summary
Summary of Changes and Additions to Site Characterization Repon
Project Organization
Overview
Residential Propeny
Windblown Dust
May 29, 1986 Interim Remedial Measures Update
Construction
RIIFS Project Status Update
Site Characterization Repon
Fugjtive Dust Monitoring
Soils Verification
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Table 2
Public ~I~tings Summary
Residential Soils Operable Unit
Bunker Hill Superfund Site
Page 5 or 6
Date Description (Subjects Discussed)
April 10. 1986 Interim Remedial Measures Update
Public Comment
Contract with Local Officials
Contractual-Administrative Update
Contracts with Gulf
Selected Actions
Schedule for Interim Remedial Measures Implementation
I State Activities
I
, U.S. EP A Acti..;ties
RLFS Project Status
Superfund Reauthorization
Site Characterization Report Status
Recon tam ina tion-S u rfaceiS ubs urface
March 20. 1986 Interim Remedial Measures Update
State ~atural Resource Suit
February 13. 1986 Interim Remedial ~feasures Update
Interim Remedial ~feasures RecommendationsuWorkshop
January 9. 1986 Status Report of Lead Health Project
Result5 of 1985 Blood Lead Screening
Winter Screening
Status Report on Public Interim Remedial Measure Sites
Engineering Alternatives
Remedial CoSt5 for Representative Sites
Update of State's Natural Resource Suit
Bunker Hill Complex Issues
December 5, 1985 Status Report on Site Tour
Status Report on Site Characteriz.1tion Report
October Z~, 1985 Status Report on Blood wd Sampling
Site Characterization Report
Status of Site Visit
Comment5 Received on Site Characterization Report
Schedule for Completion oC Site Characterization Report
Fast- Track-Interim Remedial Measures Update
Status Report
Ranking Process-Public Sites
Potential Remedies
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Table 2
Public Meetings Summary
Residential Soils Operable Unit
Bunker Hill Superfund Site
Page 6 or 6
Date Description (Subjects Discussed)
September 19, 1985 Status Report on Blood Lead Screening
Status Report on Fast-Track Program
Review of Sampling Locations
Sampling ResultS
Future Activities
Site Characterization Report
Purpose and Use of Site Characterization Report
Overview of Site Characterization Report
Where Site Characterization Report FitS in Oeanup Process
Summary of Conclusions
Additional Data RequirementS
August I, 1985 Status Report on Health Screening
Revised Community Relations Plan
Areas of Task Force Involvement
Community Relations
Update on Status of Consent RequestS
Status Report on Site Characterization
Status Report on Soils Characterization
Update on Fast-Track Program
June 27, 1985 Status Report of Data Review
System Overview
Organizations Visited
Information Available to Date
Information Exchange
Lead Health Issue
Historical Overview
Emissions and Air Monitoring Data
Overview of 1974 Lead Health Survey
Overview of 1983 Lead Health Survey
Current Status of Lead Health Program
Status Report on Soils Characterization
Fast-Track Sampling Program
Overview of Fast-Track Program
Status Report on Sampling Program
Future Fast-Track Activities and Needs
Overview of Community Relations Plan
May 16, 1985 Superfund Overview
Cooperative Agreement
ElementS of the Investigation
PRPslLiability
TechnicalJRemedial Activities
Health and Interim Remedial Actions
Community Relations
Innovative Solutions
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Table J
Fact ShedS and Other Information Distributed Door to Door
Residential Soils Operable Unit
Bunker HiJl Superfund Site
Page 1 of 2
Date Description
August 12. 1991 Superfund Progress Report. Bunker Hill-Hillsides Project
April 26, 1991 The Proposed Plan for Qeanup of the Residential Soils Within the
Bunker Hill Superfund Site
February 23. 1991 Project Update: Bunker Hill Superfund Site, Shoshone County, Idaho
I January 18. 1991 Bunker Hill Superfund Project. Kellogg, Idaho: Summary of 1990
AccomplishmentS
October 25, 1990 Summary of Findings Risk As.sessmenuData Evaluation Report
(RADER) Populated Areas
October 2. 1990 Bunker Hill Superfund Site. Kellogg, Idaho; Hillside Stabilization and
Revegetation Order Signed
September 1990 The Superfund Process at Bunker Hill
July 2~, 1990 Superfund FJct Shee~ Bunker Hill Superfund Site, Kellogg, Idaho
July 11, 1990 Bunker Hill Superfund Site. Kellogg, Idaho; Invitation to Superfund TJSk
Force Meeting (July 19)
April 9, 1990 Bunker Hill Superfund Site, Kellogg, Idaho; Invitation to Superfund TJSk
Force ~feeting (April 12)
March 19, 1990 Bunker Hill Superfund Site Project Update, Kellogg, Idaho; Proposed
PJge Pond Landfill
February 26, 1990 Bunker Hill Superfund Site Fact Sheet. Kellogg, Idaho
December 1989 Bunker Hill Superfund Site FJct Sheet. Kellogg, Idaho
September 1989 Bunker Hill 1989 Residential Soil Removal Action Cost Summary
through 9(l.9189
March 1989 Panhandle Health District 1: Notice
September 1988 Bunker Hill Superfund Fact Sheet
July 1988 Bunker Hill Superfund Project Update
February 26, 1988 Leuer to Silver Valley Task Force chairman concerning how U.S. EP A
and IDHW wiJl proceed with the RIJFS process
December 1987 Bunker Hill Superfund Project Progress Update
August 11, 1987 Leuer to Interested Parties regarding Remedial InvestigationJFeasibility
Studies--Bunker Hill Superfund Site
June 1987 Memo to Silver Valley Bunker Hill Superfund TJSk Force
May 1987 Status Report: Bunker Hill Superfund Project
~tarch 1987 Bunker Hill Superfund Site Update
~
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Table 3
Fact Sheets and Other Information Distributed Door to Door
Residential Soils Operable Unit
Bunker Hill Superfund Site
Page 2 of 2
Date Description
January 1987 Fact Sheet: The Bunker Hill Superfund Site Process
July 1986 Memo (0 Silver Valley Superfund Task Force regarding Silver Valley
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GLOSSARY Al''ffi LIST OF ACRONYMS
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GLOSSARY
Acceptable Daily Intake. The amount of toxicant, in ppm body weight/day, that will not cause adverse
effects after chronic exposure to the general human population.
Acceptable Intake for Chronic Exposure. The highest human intake of a chemical, expressed as ppm/
day, that does not cause adverse effects when exposure is long term (lifetime). The AlC is usually based
on chronic animal studies.
Acceptable Intake for Subchronic Exposure. The highest human intake of a chemical, expressed ppm/
day, that does not cause adverse effects when exposure is short term (but not acute). The AlS is usually
based on subchronic animal studies.
AmbienL Environmental or surrounding conditions.
ARARs. Applicable or Relevant and Appropriate Requirements.
Background Exposure. Exposure under conditions offsite and in unimpacted areas.
Baseline Exposure. Exposure under onsite conditions with no remediation (no-action scenario.)
Cancer. A disease characterized by the rapid and uncontrolled groWth of aberrant cells into malignant
tumors.
Carcinogen. A chemical that causes or induces cancer.
Chronic. Occurring over a long period of time, either continuously or intermittently; used to describe
ongoing exposures and effects that develop only after a long exposure.
Chronic Daily Intake. The projected human intake of a chemical averaged over a long time period, up
to 70 years, and expressed as ppm/day. The CDI is calculated by multiplying long-term by the concentra-
tion human intake factor, and it is used for chronic risk characterization.
Chronic Exposure. Long-term, low-level exposure to a toxic chemical.
ConcomitanL To accompany or to be concurrent.
Dermal Exposure. Contact betWeen a chemical and the skin.
Dermal Of the skin; through or by the skin.
Dose-Response AssessmenL The second step in the toxiciry assessment process that involves defining
the relationship betWeen the exposure level (dose) of a chemical and the incidence of the adverse effect
(response) in the exposed populations.
DusL Airborne solid particles, generated by physical processes such as handling, crushing, grinding of
solids, ranging in size from 0.1 to 25 microns.
Endangerment AssessmenL A site-specific assessment of the actual or potential danger to public health,
welfare, or the environment from the threatened or actual release of a hazardous substance or waste
from a site. The endangerment assessment document is prepared in support of an enforcement action
under CERCLA or RCRA
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Environmental Fate. The destiny of a chemical after release to the environment; involves considerations
such as transport through air, soil and water, bioconcentration, degradation, ete.
Etiologic Agent. An agent responsible for causing disease.
Exposure Assessment. One of the componentS of the endangerment assessment process. The exposure
assessment is a four-step process to identify actual or potential routes of exposure, characterize popula-
tions exposed, and determine the extent of the exposure.
.
Exposure Scenario. A set of conditions or assumptions about sources, exposure pathways, concentrations
of toxic chemicals, and populations (numbers, characteristics and habitS) that aid the investigator in
evaluating and quantifying exposure in a given situation.
..
Fu~itive Releases. Emissions that occur as a result of normal plant operations due to thermal and
mechanical stress. Fugitive dustS may result from vehicle reentrainment. soil movement by earth-moving
equipment. or wind erosion of contaminated surfaces.
Hazardous Waste. Hazardous waste, as defined in Title ~ of the Code of Federal Regulations, is a
legal rather than a scientific term. To be considered hazardous, a waste must be on the list of specific
hazardous waste streams or chemicals, or it must exhibit one or more of certain specific characteristics
including ignitability. corrosivity, reactivity. and toxicity. The definition excludes household waste, agri-
cultural waste returned to the soil, and mining overburden returned to the mine site. It also exdudes all
wastewater discharged directly or indirectly to surface waters.
High-Risk Child. Those children possessing several of the following risk co-factors observed to influence
blood lead levels. Soil/dust ingestion rates are 90 to 100 mg/day for this group. Associated risk co-
factors for classification are: a) chewing of fingernails and mouthing of objectS; b) nonvegetated
uncovered outdoor play area; c) poor quality housekeeping or high indoor dust levels; d) lack of dieta
vitamin supplementS; e) smoking parent in home; f) <510,000 per year home income; and g) parentS
possess less than a secondary level of education.
Low-Level Threat Wastes. Those source materials that generally can be reliably managed with little
likelihood of migr:nion and that prescnt a low risk in the event of exposure. They include source
materials that exhibit low mobility in the environment or are above protective levels but are nO[ consi-
dered to be significantly above protective levels for toxic compounds.
Mean. A statistical estimate of central tendency. Two different means are employed here: arithmetic
mean and geDmetric mean. Arithmetic means approximate data centroids when data is normally
distributed. Geometric means approximate data a:ntroids when data is log-normally distributed. Arith-
metic Mean ~ GeDmetric Mean for the same data population.
National ~farket Basket Variety Produce. Vegetable. fruit. and meat produce distributed nationally and
available on supermarket shelves, which constitutes the source of food for the average consumer.
Pathway. A history of the flow of a pollutant from source to receptor, including qualitative descriptions
of emission type, transport, medium, and exposure route.
Pica. Refers ro both normal mouthing and subsequent ingestion of nonfood items, which is quite
common among children at certain ages, and the unnatural craving for and habitual ingestion of nonfood
items. The latter is an uncommon condition that is generally associated with medical conditions such as
malnutrition. certain neurobehavioral disorders, and iron deficiency anemia or, less often, with a parti-
cular cultural background.
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Plume. Term used to describe the distribution of contaminants.
Population at Risk. A population subgroup that is more likely to be exposed to a chemical, or is more
sensitive to a chemical, than is the general population.
Principal Thre:lt Wastes. Those source materials considered to be highly toxic or highly mobile that
generaIly cannot be reliably controIled and that present a significant risk to human health or the
environment. They include liquids, highly mobile materials (e.g., solvents), or high concentrations of
toxic compounds.
Risk Assessment. A qualitative or quantitative evaluation of the environmental and/or health risk
resulting from exposure to a chemical or physical agent (pollutant); combines exposure assessment
results with toxicity assessment results to estimate risk.
Risk Characterization. The final component of the endangerment assessment process that integrates all
of the information developed during the exposure and toxicity assessments to yield a complete character-
ization of the actual or potential risk at a site.
Route or Exposure. The avenue by which a chemical comes into contact with an organisms (e.g., inhala-
tion, ingestion, dermal contact, injection).
Scenario. A set of assumptions describing how exposure takes place. Scenarios are usually constructed
in the "Integrated Exposure Analysis" section of an exposure assessment and are usually specific to an
exposure setting.
Standard Deviation. A statistical estimate of variability associated with a data population. One stan-
dard deviation surrounding the mean includes 68 percent of the data population, and tWo standard devi-
ations surrounding a mean includes 95 percent of the population.
Subchronic. Of intermediate duration, usually used to describe studies or levels of exposure betWeen 10
and 90 days.
Subchronic Daily Inbke. The projected human intake oC a chemical averaged over a short time period,
expressed as ppm/day. The SOl is calculated by multiplying the short-term concentration by the human
intake factor, and it is used for subchronic risk characteriZ3tion.
Toxicity Assessment. One of the components of the endangerment assessment process, the toxicity
assessment is a tWo-step process to determine the nature and extent of health and environmental hazards
associated with exposure to contaminants of concern present at the site. It consists of toxicological eval-
uations and dose-response assessments for contaminants of concern.
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Ag
AlC
ARAR
As
ATSDR
Bl-Pb
Ca
CJ
CDC
CDr
CERCL\
CIA
Co
CPF
Cr
crv
Cu
Dr
EA
EECA
EEPC
EP
EPTo:t
FDA
Fe
GRC
HAD
HEA
HIF
rDAPA
rDHW
IRIS
K
Mg
Mn
~g/dl
~g/m3
Na
NCP
NHANES
Ni
NPL
OSHA
OSWER
Pb
Pb-B
PHD
PO
ACRONTI-IS AND ,ABBREVIATIONS
Silver
A~ptable Intake for Chrcmic E-q>Osure
AppliClble or Relevant and Appropriate Requirement
Arsenic
Agency for TO:Qc Substances and Disease Registry
Blood Lead Level: also as Pb-B
. Calcium
Cadmium
Centers for Dis~e Control
Chronic Daily Imake
Comprehensive En..ironmcntal Response. Compensation and Liabiliry Act
Ccntr:ll Impoundment ..\rea .
Cobalt
Cancer Potency FactOr
Chromium
CritiClI TO:Qciry Value
Copper
Daily Intake
Endangerment Assessment
Engineering Evaluation Jnd Cost An a 1)'5 is
Engineering Evaluation for Pha.se.d Oeanup
Erythrocyte ProtOporph:--Tin
E'
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ppb
ppm
PRP
RAO
RCRA
RID
RIIFS
RME
ROD
Sb
Se
SFCDR
SPHEM
TBC
TCLP
11
TLV-lWA
1'$CA
1'$0
U.S. EPA
V
Zn
Acronyms and Abbreviations (cont.)
Parts per billion
Parts per million = ,u.g/gm = mg/kg
Potentially Responsible Party
Remedial Action Objective
Resource Conservation and Recovery act
Reference Dose
Remedial InvestigationiFeasibility Study
Reasonable Maximum E'<]X>sure
Record of Decision
Antimony
Selenium
South Fork of the Coeur d'AJene River
Superfund Public Health Evaluation Manual
To-Se-Considered
Toxicity Characteristic Leaching Procedure
Thallium
Threshold Limit ValuesnTime-Weighted Average
Toxic Substance Control Act
Treatment, Storage and Disposal Facility
U.S. Environmental Protection Agency
Vanadium
Zinc
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