FIVE YEAR REVIEW OF THE WHITEWOOD CREEK SUPERFUND SITE
LEAD, SOUTH DAKOTA
July 2002
Prepared by:
US Environmental Protection Agency
Region VIII
999 18th Street, Suite 500
Denver, CO 80202
With technical assistance from:
Syracuse Research Corporation
Environmental Science Center - Denver
999 18th Street, Suite 1975
Denver, CO 80202
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USEPA FIVE-YEAR REVIEW SIGNATURE COVER
Key Review Information
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Site Name: WHITEWOOD CREEK
EPA ID: SDD980717136
Region: 8
State: SD
City/County: Whitewood/ Lawrence County
SIT
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NPL Status: DELETED
Remediation Status:
COMPLETE
Multiple OUs: N
Number of OUs: 1
Construction Completion Date: December 21, 1992
Fund/PRP/Federal Facility lead: PRP
Lead agency: USEPA Region VIII
Has site been put into reuse? N
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Who Conducted the review (USEPA Region, State, Federal agency): USEPA Region
Author name: Rebecca Thomas
Author title: Remedial Project Manager
Author Affiliation: USEPA Region VIII
Review Period: 7/1996 to 12/2001
Date of site inspection: July 16 & 17, 1996
Review Type: STATUTORY
Review Number: 1
Triggering Action Event: Start date of Remedial Action
Trigger Action Date: September 25, 1991
Due Date: January 31, 1997
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TABLE OF CONTENTS
1.0 INTRODUCTION 1 - 1
1.1 Purpose of Review 1-1
1.2 Statute Requirements 1-1
1.3 First Review 1-2
1.4 Triggering Action for Review 1-2
1.5 Structure of the Five-Year Review Report 1-3
2.0 SITE CHRONOLOGY 2 - 1
2.1 Initial Discovery of Contamination 2-1
2.2 National Priorities List (NPL) Listing 2-2
2.3 Decision and Enforcement Document 2-2
2.4 Start and Completion of Remedial Actions 2-2
2.4.1 Remediation of Soils at Residences 2-3
2.4.2 Land Use Institutional Controls 2-3
2.4.3 Annual Education Program 2-4
2.4.4 Extent of Contamination and Delineation of 100 Year Floodplain . . . 2-4
2.4.5 Surface Water Monitoring Program 2-4
2.5 Construction Completion 2-5
2.6 Prior Five Year Reviews 2-5
3.0 BACKGROUND 3 - 1
3.1 Physical Characteristics 3-1
3.2 Site Environmental Setting 3-1
3.2.1 Vegetative Cover 3-2
3.2.2 Aquatic Ecology 3-4
3.3 Land and Resource Use 3-5
3.3.1 Former, Current, and Projected Land Use 3-5
3.3.2 Human Use of Resources 3-5
3.4 History of Contamination 3-7
3.4.1 Historical Activities that Caused Contamination 3-7
3.4.2 Site Contaminants and Risks 3-9
4.0 REMEDIAL ACTIONS 4 - 1
4.1 Remedy Selection 4-1
4.2 Remedy Implementation 4-3
4.2.1 Residential Remediation 4-3
4.2.2 Institutional Controls 4-7
4.3 Operation and Maintenance 4-11
4.3.1 Surface Water Monitoring 4-12
4.3.2 Annual Site Resident Education Program 4-15
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4.3.3 Future Development Restrictions-Annual Review of Residential
Building Activity 4-16
4.3.4 Post-Closure Residential Soil Sampling and Remediation 4-18
4.3.5 Disposal Site Monitoring 4-21
4.3.6 Reporting 4-21
5.0 FIVE YEAR REVIEW FINDINGS 5 - 1
5.1 Five-Year Review Process 5-1
5.1.1 Interview Team Members 5-1
5.1.2 Community Notification 5-1
5.1.3 Five-Year Review Tasks 5-2
5.2 Interviews 5-3
5.2.1 Interviews with Residents 5-3
5.2.2 Interviews with Government Officials 5-6
5.2.3 Interviews with Remediation Contractors and O&M Contractors . . 5-15
5.2.4 Interviews with Homestake Mining Corporation 5-19
5.2.5 Summary of Interview Results 5-22
5.3 Site Inspection 5-24
5.3.1 Date and Conduct of Site Inspection 5-24
5.3.2 Activities 5-24
5.3.3 Summary of Site Conditions 5-25
5.4 Risk Information Review 5-25
5.4.1 ARARs Reviewed 5-26
5.4.2 Review of Site-Specific Cleanup Level 5-30
5.5 Risk Recalculation and Assessment 5-30
5.5.1 Human Health Risk Assessment 5-31
5.5.2 Ecological Risk Assessment 5-31
5.6 Data Review 5-35
5.6.1 Residential Verification Sampling 5-35
5.6.2 Surface Water Quality 5-36
6.0 ASSESSMENT 6 - 1
6.1 Have External Conditions Changed Since the Remedy? 6-1
6.1.1 Changes in Land Use 6-1
6.1.2 Changes in Known Contaminants, Sources and Pathways 6-1
6.1.3 Changes in Known Hydrologic or Hydrogeologic Conditions 6-2
6.2 Has the Remedy Been Implemented in Accordance with Decision Documents? 6-2
6.2.1 Health and Safety Plan (HASP) and Contingency Plan 6-2
6.2.2 Access and Institutional Controls 6-2
6.2.3 Remedy Performance 6-5
6.2.4 Adequacy of System Operations/O&M 6-6
6.2.5 Need for Optimization 6-8
6.2.6 Early Indicators of Potential Remedy Failure 6-8
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6.3 Has Any Risk Information Changed Since the Remedy was Selected? 6-9
6.3.1 Changes in ARARs 6-9
6.3.2. Changes in Risk Information 6-10
7.0 DEFICIENCIES 7 - 1
7.1 Deficiencies in the Future Development Restrictions 7-1
7.2 Deficiencies in the Annual Resident Education Program 7-2
8.0 RECOMMENDATIONS AND REQUIRED ACTIONS 8 - 1
8.1 Recommendations for Future Development Restrictions 8-2
8.1.1 Updated Maps 8-2
8.1.2 Notification of Development Activities 8-3
8.1.3 Follow-up Visits With Properties Identified During the Five-Year
Review 8-3
8.1.4 Provide Maps and Reference Materials to Counties 8-3
8.2 Recommendations for the Annual Resident Education Program 8-4
9.0 PROTECTIVENESS STATEMENT(S) 9 - 1
9.1 Residential Remediation 9-1
9.2 Institutional Control Implementation 9-1
9.3 Protection of the Environment 9-1
10.0 NEXT REVIEW 10 - 1
11.0 REFERENCES 11 - 1
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ATTACHMENTS
Attachment 4-1
Building Permit Handbook for Butte, Meade and Lawrence Counties
Attachment 4-2
Annual Education Program Materials
Attachment 5-1
Notification of Upcoming Five Year Review
Attachment 5-2
List of Documents Reviewed
Attachment 5-3
Ecological Risk Assessment (ERA) of the Whitewood Creek Superfund
Site (electronic file)
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LIST OF TABLES
Chronology of the Former Events at the Whitewood Creek Superfund Site
Summary of Residential Remediation Activities
Review of Residential Building Activities Within the Whitewood Creek Superfund
Site
Summary of Observations and Remedial Actions Taken During Annual Inspections
of the Disposal Site
Summary of Quarterly Reports Submitted During Site Operation and Maintenance
Activities
Applicable or Relevant and Appropriate Requirements (ARARs) for the
Whitewood Creek Superfund Site
Changes in Chemical-Specific ARARs
Summary of the Changes in Stringency of Site Chemical-Specific ARARs
Changes in Action-Specific ARARs
Summary of the Results of the SERA
Summary of Data Gaps Identified in the SERA
Summary of the Five-Year Review Residential Verification Sampling Results
Summary Statistics for Surface Water Time Trend Plots
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LIST OF FIGURES
Location of Whitewood Creek Superfund Site
Schematic Representation of the Geology and Water-Circulation Pathways in the
Whitewood Creek Valley
As Constructed Diagram of the Whitewood Creek Superfund Site Disposal Area
Post-construction Photo of a Soil Disposal Cell, Spring 1994
Detailed Boundaries within the Whitewood Creek Superfund Site
Homesite Development Flowchart for the Whitewood Creek Tailings Area
Photos Taken During Disposal Site Operation and Maintenance Activities
Unauthorized Rubble Placed Outside of the Disposal Site
Sampling Stations Map
Time Trend Analyses for Contaminants in Surface Water
Comparison of Time Trend Plots for Contaminants in Surface Water with Fish
Consumption AWQC
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LIST OF ACRONYMS
ARARs Applicable or Relevant & Appropriate Requirements
ARSD Administrative Rules of South Dakota
AWQC Ambient Water Quality Criteria
BOR Bureau of Reclamation
CERCLA Comprehensive, Environmental Response, Compensation and Liability Act
CERCLIS Comprehensive, Environmental Response, Compensation and Liability
Information System
CFR Code of Federal Regulations
COPC Constituent of Potential Concern
DGFP Department of Game, Fish and Parks
DWNR Department of Water and Natural Resources
EA Endangerment Assessment
ERA Ecological Risk Assessment
ESD Explanation of Significant Difference
FDA Food and Drug Administration
FEMA Federal Emergency Management Agency
FIRM Flood Insurance Rate Map
FS Feasibility Study
GS Geological Survey
HQ Hazard Quotient
MCL Maximum Contaminant Level
NCP National Contingency Plan
NPL National Priorities List
O&M Operation and Maintenance
PM10 Particulate Matter with a diameter of 10 micrometers or less
PNL Pacific Northwest Laboratory
PRP Primary Responsible Party
QAPP Quality Assurance Project Plan
ROD Record of Decision
SC Specific Conductance
SD South Dakota
TSS Total Suspended Solids
SRC Syracuse Research Corporation
USEPA United States Environmental Protection Agency
USGS United States Geological Survey
WAD Weak Acid Dissociable (cyanide)
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1.0 INTRODUCTION
The United States Environmental Protection Agency (USEPA) Region VIII has conducted a
five-year review of the remedial actions implemented at the Whitewood Creek site in Lead, South
Dakota. This review was conducted from July 1996 through December 2001. The report was
completed by USEPA Region VIII with technical assistance from Syracuse Research Corporation
(SRC). This report documents the results of the five-year review.
1.1 Purpose of Review
As specified in the Record of Decision (ROD) for the Whitewood Creek site, a review of the
remedial action will be conducted no less than each five years after initiation of the remedial
action to ensure that human health and the environment are being protected (USEPA, 1990).
Therefore, the purpose of this five-year review is to determine whether the remedy at the
Whitewood Creek site is protective of human health and the environment. The methods, findings
and conclusions of the review are documented in this five-year review report. In addition, the
five-year review report identifies deficiencies found during the review, if any, and provides
recommendations to address them.
1.2 Statute Requirements
USEPA must implement five-year reviews consistent with the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA) and the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP). CERCLA section 121(c), as amended, states:
If the President selects a remedial action that results in any hazardous substances,
pollutants, or contaminants remaining at the site, the President shall review such
remedial action no less often than each five years after the initiation of such remedial
action to assure that human health and the environment are being protected by the
remedial action being implemented.
The NCP part 300.430(f)(ii) of the Code of Federal Regulations (CFR) states:
If a remedial action is selected that results in hazardous substances, pollutants, or
contaminants remaining at the site above levels that allow for unlimited use and
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unrestricted exposure, the lead agency shall review such action no less often than every
five years after the initiation of the selected remedial action.
1.3 First Review
This is the first five-year review for the Whitewood Creek Site. On behalf of Homestake,
Chadwick Ecological Consultants, Inc. (Chadwick) initiated the five-year review of the
Whitewood Creek site and submitted their findings in a report dated January 1997 (Chadwick et
al., 1997). Among the comments on this five-year review report, USEPA identified the need for
additional studies to be conducted at the Site, including an ecological risk assessment (USEPA,
1997a).
In a letter responding to USEPA, dated November 7, 1997 (George, 1997), Homestake refused
to conduct any additional studies at the Site, and invoked the dispute resolution provision of the
Consent Decree. Homestake argued that the terminated 1990 Consent Decree was no longer a
valid tool for USEPA to use to seek additional studies related to the Site.
USEPA invoked Section VII of the Consent Decree, directing Homestake to perform additional
work in connection with the Five-Year Review of the Site. This request was later withdrawn, and
USEPA proceeded with the additional studies of the Whitewood Creek site on a cost-recovery
basis.
This five-year review report includes the findings from the 1997 report submitted by Homestake
(Chadwick et al., 1997) and the additional studies of Whitewood Creek to complete the first
five-year review of the Site.
1.4 Triggering Action for Review
In keeping with the requirements of CERCLA 121(c) and the NCP, statutory reviews are
triggered by the initiation of a remedial action that will result in hazardous substances, pollutants,
or contaminants remaining onsite above levels that allow for unlimited use and unrestricted
exposure after the remedial action is complete. The earliest remedial action associated with a
remedy that will leave hazardous substances, pollutants, or contaminants at the site triggers a
statutory five-year review (USEPA, 1999a).
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The remedy implemented at the Whitewood Creek site resulted in mine tailings remaining at the
site above levels that allow unlimited use and unrestricted exposure (USEPA, 1990). Thus, a
statutory five-year review is required to be conducted to ensure that human health and the
environment are being protected. The trigger date for the statutory review is September 25,
1991, which is the start date for remedial action activities reported in USEPA's Comprehensive
Environmental Response, Compensation, and Liability Information System (CERCLIS) database.
The Consent Decree (United States v. Homestake, 1991) requires that USEPA review the Site no
less often than every five years after initiation of the Remedial Action to assure that human health
and welfare and the environment are being protected by the work implemented in the Consent
Decree.
The five-year review completion date was modified by the Site Operations and Maintenance
(O&M) Plan (WDC, 1994b). The O&M plan requires five-year data review collection activities
to be completed within five years of the remedial action start date, by September 25, 1996, and
the Five-Year review report to be completed by January 31, 1997. This modification was made to
allow a reasonable amount of time to transpire before embarking on the significant data collection
and soil sampling activities associated with the five-year review for this Site (USEPA, 1996). A
schedule based on the Five-Year Review Report being completed within five years of the start
date of the remedial action (September, 1996), would have required five-year review soil sampling
activities to occur within three years following completion of remediation (USEPA, 1996). The
modified schedule requires sampling activities to be completed by September 25, 1996 and the
five-year review report to be completed by January 31, 1997, and on the five year anniversaries of
these dates.
1.5 Structure of the Five-Year Review Report
The five-year review is completed according to the Comprehensive Five-Year Review Guidance
(USEPA, 1999a). The document is organized into eleven sections, as recommended by the
guidance:
Introduction. Chapter 1 provides the introduction of the five-year review. This is a
synopsis of the five-year review process including who performed the review, the purpose
of the review, the statutory requirements for the review, the trigger for the review and the
structure of the report.
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Site Chronology. Chapter 2 provides the chronology of the Whitewood Creek site. This
includes major events, documents, and remedial actions.
Background. Chapter 3 provides a description of the Site including physical setting, land
and resource use, contaminants and initial response.
Remedial Actions. Chapter 4 provides a description of the remedial action objectives, the
remedy, remedy implementation, O&M requirements and O&M activities to date.
Five-Year Review Findings. Chapter 5 describes the findings of the five-year review
including the results of interviews, site inspection, ARAR review, risk recalculations,
ecological risk assessment results and data review.
Assessment. Chapter 6 provides a discussion of the conclusions reached in the five-year
review.
Deficiencies. Chapter 7 discusses any deficiencies identified in the remedial action.
Recommendations and Required Actions. Chapter 8 provides any recommendations and
actions required to achieve protectiveness. The recommendations include the responsible
parties, agencies with oversight authority and the recommended schedule for completion.
Protectiveness Statements). Chapter 9 provides the protectiveness statement(s) for the
Whitewood Creek site.
Next Review. Chapter 10 provides a statement on when the next review is required, the
trigger for the next review and the tasks to be performed as part of the review.
References. Chapter 11 provides the references for the five-year review document.
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2.0 SITE CHRONOLOGY
Table 2-1 summarizes the chronology of events at the Whitewood Creek Site.
2.1 Initial Discovery of Contamination
From 1877 to 1977, operations at the Homestake Mine involved the direct discharge of tailings
into Whitewood Creek. Since 1977, process materials and water have been treated prior to
discharge. In 1960, the South Dakota (SD) Department of Health quantified solids and cyanide
loading to Whitewood Creek. In 1965, the SD Department of Game, Fish and Parks (DGFP)
concluded that aquatic bottom organisms were absent in Whitewood Creek downstream from the
waste discharges. From 1970 to 1971, a series of studies by USEPA, the US Food and Drug
Administration (FDA) and the University of SD were conducted to document the magnitude and
extent of the tailings. The studies focused on the environmental hazards associated with mercury
and their results led to the discontinuation of mercury amalgamation process by Homestake. In
December 1970, results of these studies led to the discontinuance of mercury in gold recovery
operations (USEPA, 1990).
In the winter of 1974-75, about 50 Holstein cattle that were part of a dairy operation located
adjacent to Whitewood Creek died of unknown causes. Later, a study by the SD University
Department of Veterinary Science concluded that the cattle had died of arsenic toxicosis due to
consumption of corn silage that had been contaminated by the accidental incorporation of mining
wastes with fodder during silo-filling operations. A joint study, conducted by the SD Geological
Survey (GS) and the SD Water Resources Division between May 1975 and July 1978,
investigated the presence of arsenic in surface and groundwater along Whitewood Creek, the
Belle Fourche River and portions of the Cheyenne River. This study, published in 1978, found
arsenic concentrations ranging from 2.5 to 1,530 ug/L in groundwater from areas with large
tailings deposits (USEPA, 1990).
One common conclusion of these investigations was that Whitewood Creek would remain highly
contaminated until the discharge of tailings was discontinued. To comply with new environmental
laws, including the Ore Mining and Dressing Effluent Guidelines, Homestake implemented the
Grizzly Gulch Tailings Disposal project, an impoundment area for tailings storage. The tailings
disposal system became operational on December 1, 1977. Since 1977, no tailings have been
discharged into Whitewood Creek (USEPA, 1990).
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2.2 National Priorities List (NPL) Listing
The Whitewood Creek site was placed on the interim National Priorities List (NPL) at the request
of the governor of South Dakota in September 1981. At this time, USEPA sent a notice letter to
Homestake regarding potential liability. On September 8, 1983, the Whitewood Creek site was
placed on the NPL. Homestake submitted a petition to USEPA to delete Whitewood Creek from
the NPL. A report entitled Assessment of Exposure and Possible Effects on Human Health of
Gold Mine Tailings in the Whitewood Creek Area of South Dakota was completed in April of
1985 by Environ Corp. to support Homestake's petition for delisting. Homestake also submitted
a second petition for delisting the Site in 1985, which was rejected by USEPA as being premature.
In 1996, the Whitewood Creek site was deleted from the NPL (USEPA, 1990).
2.3 Decision and Enforcement Document
In December of 1988, an Administrative Order on Consent was signed by USEPA and
Homestake. This order concluded that the studies completed by Fox Consultants, Inc., (1984a
and 1984b) constituted the functional equivalent of a remedial investigation, as prescribed by the
National Contingency Plan (NCP). The order required that Homestake conduct a Feasibility
Study (FS) to identify and evaluate alternatives for remedial action (USEPA, 1990). In July of
1989, the Final Environmental Assessment (EA) was completed by USEPA with the assistance of
Jacobs Engineering (Jacobs, 1989). In December of 1989, the FS was completed by ICF
technology on behalf of Homestake (ICF, 1989a and 1989b). In January of 1990, the
Administrative record was established and in March of 1990 the ROD was issued (USEPA,
1990). In August 1990, USEPA and Homestake signed a Consent Decree for Homestake to
implement the ROD through Remedial Design and Remedial Action at the Site. This agreement
was lodged in the U.S. District Court for South Dakota on October 10, 1990, (Case Number
90-5101), and entered by the Court on April 4, 1991.
2.4 Start and Completion of Remedial Actions
The selected remedial action for the Whitewood Creek site includes:
Removal and/or covering frequently used areas of residential sites with arsenic
levels above 100 mg/kg with clean surface soil (arsenic <20 mg/kg);
Disposal of the arsenic-contaminated soil;
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Revegetation of the remediated area;
Soil sampling at all remediated areas to confirm that arsenic levels are below 100
mg/kg;
Implementing institutional controls including land and access restrictions;
Conducting an annual education program to inform site residents of the potential
health hazards associated with exposure to tailings, soil, and alluvial groundwater
contaminated with arsenic;
Refining knowledge of the extent of contamination and delineating the 100-year
floodplain of Whitewood Creek; and
Surface water monitoring.
USEPA invoked Applicable or Relevant and Appropriate Requirement (ARAR) waivers based on
the technical impracticability of remediating contaminated ground and surface waters. The
estimated cost of the remedial action at the time of the ROD was $882,813, which includes an
annual Operation and Maintenance (O&M) cost of $12,000 for years 1 to 5 and $6,000 for years
6 to 30 (USEPA, 1990).
2.4.1 Remediation of Soils at Residences
In 1992, remediation was completed at 16 residences. Approximately 4,500 cubic yards of
materials were removed from the individual residences/sites and placed at the on-site disposal
facility (USEPA, 1993).
On July 16 and 17th 1996, inspections and interviews were conducted at all remediated sites as
part of the five-year inspection and interview program. The residential five-year verification
sampling program was conducted on July 18 and 19, 1996 by Homestake at 6 of the residential
properties located within the boundaries of the Superfund site. One property contained arsenic
concentrations above the site action level of 100 mg/kg. This property (the Holsclaw residence)
was remediated in accordance with the Site Operation and Maintenance (O&M) Plan (WDC,
1994b)
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2.4.2 Land Use Institutional Controls
Land Use Restrictions
The institutional control portion of the remedy was implemented during 1993 and 1994. In
accordance with the requirements of the ROD, Butte, Meade and Lawrence Counties adopted
ordinances in late 1993 and early 1994 that prohibited construction of new residential or
commercial structures on the tailings deposits, restricted future development in tailings-impacted
areas of the Site, and prohibited removal and use of tailings from outside the tailings areas. A
county building permit handbook was developed to aid in the future implementation of the
proposed ordinances, and approved by USEPA on November 29, 1993. The handbook defines
the steps necessary for residential development of the tailings impacted areas (WDC, 1994b).
State Well Ban Regulation
A State well ban regulation prohibiting wells in the 100 year floodplain of Whitewood Creek
remains in effect to limit exposure to groundwater from the downgradient alluvial aquifer.
2.4.3 Annual Education Program
In 1993, Homestake began distributing an annual fact sheet to educate the public on Site hazards
and ways to minimize the risk posed by residual contamination (USEPA, 1994). Educational
materials were distributed annually to residents during the first quarter of each year from 1993
through 2001.
2.4.4 Extent of Contamination and Delineation of 100 Year Floodplain
The boundaries of the tailings deposits, tailings impacted soils and the 100-year floodplain
boundary of Whitewood Creek were delineated during extensive field programs that began the
summer of 1991 and ended in the fall of 1992. The detailed maps for these boundaries were
approved by USEPA on April 15, 1993 (WDC, 1994a).
2.4.5 Surface Water Monitoring Program
The surface water monitoring program was implemented in May of 1993 to evaluate the unknown
rates of release of arsenic from the tailings deposits in Whitewood Creek. Homestake collected
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water samples four times annually from two United States Geological Survey (USGS) gauging
stations from May 1993 to present. The first USGS station is 06436180 (Whitewood Creek
above Whitewood) and is located at the upper end of the NPL site boundary, downstream of the
Crook City Bridge. The station located downstream of the confluence with Gold Run and
downstream of the tailings discharge point on Gold Run. The second USGS sampling station is
06436198 (Whitewood Creek Above Vale) is located at the downstream end of the NPL site
boundary, above the confluence with the Belle Fourche River. Sampling times occurred (1) in
late winter before major snow-melt runoff; (2) during peak runoff in the spring; (3) during the low
flow period in late summer; and (4) once immediately following a major precipitation event
(Addendum B to WDC, 1994b).
Arrangements were made between the USGS Water Resources Division, South Dakota District
Office in Rapid City and Homestake for collection and analyses of the surface water samples
(Addendum B to WDC, 1994b). Homestake submitted quarterly reports providing the results of
the sampling and analyses.
2.5 Construction Completion
Remediation activities at the residences began on September 30, 1991 with a pilot remediation
project, and were completed during the fall of 1992. Construction of the Disposal Site began on
September 30, 1991 and was completed on September 30, 1992. Construction activities at the
Topsoil and Topsoil Subgrade Borrow Site were conducted during the period of September 26,
1991 through September 18, 1992. The Temporary Stream Crossing construction began on July
29, 1992 and removal work was completed by September 7, 1992.
The re-remediation of the Holsclaw property, required as a result of the five year review
verification sampling, began in November of 1997 and was completed by late June, 1998 (WDC,
1998).
2.6 Prior Five Year Reviews
This is the first five-year review for the Whitewood Creek site. The five-year review process was
initiated by Homestake in 1996 and their findings are reported in Chadwick et al. (1997). Among
other comments and issues raised on the report, USEPA identified the need for additional studies
to be conducted at the Site to evaluate protectiveness, including an Ecological Risk Assessment
(ERA).
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This five-year review report includes the findings from the review initiated by Homestake
(Chadwick et al., 1997), the findings from the additional studies and ERA (Attachment 5-3), and
data and activities conducted as part of Site O&M. This report completes the first five-year
review of the Whitewood Creek site.
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3.0 BACKGROUND
3.1 Physical Characteristics
The former Whitewood Creek Superfund site is located in Lawrence, Meade and Butte Counties
in South Dakota (Figure 3-1). The Site is situated in west central South Dakota on the northern
perimeter of the Black Hills, 40 miles northwest of Rapid City on Interstate 90. The town of
Whitewood is located about one mile west of the Site (ISSI, 1998; Chadwick et al., 1997).
The Whitewood Creek Site encompasses the 100 year floodplain along an 18 mile stretch of
Whitewood Creek from stream mile 18 near the town of Whitewood to stream mile 0 where the
Creek flows into the Belle Fourche River. The Site includes the floodplain and surrounding areas
that have become contaminated with Site wastes.
3.2 Site Environmental Setting
Whitewood Creek is a tributary of the Belle Fourche River flowing northeast from its source in
the Black Hills of South Dakota past the Homestake Mine and the towns of Lead, Deadwood and
Whitewood before emerging onto the floodplain of the Belle Fourche on the Missouri Plateau. It
is fed by several small headwater streams that enter upstream of the 18 mile segment, and flows
into the Belle Fourche River at the downstream end of the 18 mile segment. The Belle Fourche
River joins the Cheyenne River approximately 130 miles further downstream (Fox Consultants,
Inc., 1984a).
Prior to the initiation of tailings discharge, Whitewood Creek was a small stream with insufficient
capacity to move large quantities of sediment. In adjustment to the entry of vast tonnages of
tailings sediments into the stream, the length of the stream channel diminished, primarily through
meander abandonment, thereby increasing the stream gradient and thus the stream sediment
carrying capacity. Abandoned meanders were filled with tailings and natural alluvium. Successive
layers of these sediments were deposited in overbank areas, particularly during periods of ice
jamming. As the meanders were being abandoned, the stream began a period of down cutting
along the course of the present channel. Downcutting was limited by resistant coarse alluvial
deposits and by shale outcrops that form the streambed in many places (Fox Consultants, Inc.,
1984a).
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The present course of Whitewood Creek in the 18-mile study area is a 4-braided pattern with
occasional bends or meanders within the broader bottomland. In the upper reaches of the study
area, the channel is comparatively straight with few meanders and few bends. Although the
present channel is not entirely stable, many of the overbank terraces and abandoned meanders
have tailings deposits that have been stable for many decades. A dense cover of leaf mulch, grass,
and mature trees, some of which are 2 feet in diameter, exist on many of these stable areas (Fox
Consultants, Inc., 1984a).
For Whitewood Creek within the study area, the width of the stream channel is between 40 and
80 feet and the depths from the floodplain to lowest bottomland are about 5 to 8 feet. Under base
flow conditions, the flow is approximately 20 to 50 cubic feet per second. About 10 to 25
percent of this flow is effluent discharge from the Homestake wastewater treatment plant at Lead
(Cherry et al., 1985; Fox Consultants, Inc., 1984a).
3.2.1 Vegetative Cover
Native vegetation comprises approximately 75 percent of the study area. The remaining area
consists of irrigated and nonirrigated croplands (approximately 18 percent) and
rangeland/developed areas ( 7 percent) (Fox Consultants, Inc., 1984a). Riparian woodlands are
the most abundant and widespread native vegetative community type. They are concentrated
along both the Whitewood Creek and the Belle Fourche River floodplains. Crops in the study
area include corn, oats, alfalfa, and hay from range grasses (primarily smooth brome) (USEPA,
1989a). In 1983, Fox Consultants Inc. as part of the Whitewood Creek Study Phase I (Fox
Consultants, Inc., 1984a) characterized the vegetative community using visual reconnaissance
(four occasions and three seasons) and field sampling.
Native floodplain or riparian woodland vegetation communities are dominated by plains
cottonwood (Populus sargentii), eastern cottonwood (P. deltoides), narrow-leaf Cottonwood (P.
angus tifolia), Amercian elm (Ulmus americana), green ash (Fraxinuspennsylvanica), willow
(Salix spp.), box elder (Acer negundo), Russian olive (Elaeagnus angus-tifolia), and bur oak
(iQuercus macrocarpa). Seedlings and saplings of the overstory species typically dominate
understory vegetation. Snowberry (Symphoricarpos albus) is a common shrub and perennial
grasses are the prevalent ground cover. Dominant grasses included several species of blue grass
(Poa spp.), wheatgrass (Agropyron spp.) as well as smooth brome (Bromus inermis) and prairie
cordgrass (Spartinapectinata) (Fox Consultants, Inc., 1984a). Streamside vegetation includes
willow and perennial grasses.
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General trends in the abundance and species composition of the native vegetation were reported
by Fox Consultants Inc. (1984a) between the upper and lower portions of the study area and
between the two stream floodplains. The vegetative communities are described as two zones with
plant communities exhibiting relatively constant species composition within each of the two zones.
The first zone is bounded by the confluence of Crow Creek and Whitewood Creek continuing
south (upstream) to Crook City and Whitewood. In this zone the topography is steeper and more
broken with floodplain width being more restricted. Woodland composition is dominated by bur
oak with the plains Cottonwood and narrow leaf Cottonwood occurring in relatively small
quantities. Some ponderosa pine occurs on the edge of the floodplain, near Crook City (Fox
Consultants, Inc., 1984a).
The second zone begins, generally, at the confluence of Whitewood Creek and Crow Creek
continuing along Whitewood Creek and then eastward along the Belle Fourche River. Basic
vegetation characteristics change in response to elevation and topography. The reduced gradients
and lower elevations downstream of the Whitewood Creek-Crow Creek confluence encourage an
increase in the occurrence of American elm, box elder, green ash, and a decrease in importance of
bur oak. Cottonwoods and willow attain greater frequency as the transition occurs from the
broken terrain of the foothills to the relatively level terrain of the plains. Plains cottonwood and
willow dominate the riparian woodlands with the comparative abundance of willow and
cottonwood changing on a site-specific basis depending on local hydrology. Russian olive
appears as a minor species upstream becoming increasingly more prevalent downstream (Fox
Consultants, Inc., 1984a).
The riparian corridor along Whitewood Creek generally increases in width and tree height with
increasing distance downstream. The boundaries of the woodlands closely coincide with
floodplain boundaries. Adjacent plant associations in the valley floor include fields of alfalfa, corn
and hay and rangeland used for livestock grazing. Over-grazing by livestock (cattle and sheep)
was apparent along some stream stretches (Fox Consultants, Inc., 1984a).
The riparian corridor along the Belle Fourche River is more fragmented than Whitewood Creek
due to more intense agricultural activities and as such contains a less developed riparian
woodland. The understory is less well developed, tree size is greater, fewer species were present
and the overhead tree canopy is more open. Cottonwood, willow, Russian olive, green ash, and
box elder are the primary overstory and understory species (Fox Consultants, Inc., 1984a).
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Mine tailings are reported to be confined to the floodplain (USEPA, 1989a). Although some
tailings deposits remain barren, it is reported that a plant community with limited diversity has
gradually colonized the tailings (USEPA, 1990). The barren areas have been invaded by
rhizomatous grasses, forbs and small shrubs (USEPA, 1989a). Succession appears to begin when
grasses take root in leaf litter trapped in depressions in the surface of the tailings. Some trees in
the tailings deposits have been dated at over 100 years old (USEPA, 1990). The available study
does not report plant stress in or around the tailings areas (USEPA, 1989a).
3.2.2 Aquatic Ecology
Whitewood Creek and the Belle Fourche River are the surface waters located within and adjacent
to the Site, respectively. These waters are located in the north high plains of the Black Hills
region of western South Dakota and are classified as transitional streams located between the
eco-regions of Rocky Mountain Forest and Great Plains Shortgrass Prairie (Bailey, 1982).
Whitewood Creek originates in the northern Black Hills, while the Belle Fourche River originates
in northeastern Wyoming, south of the town of Gillette. Whitewood Creek in the study area is a
moderate gradient stream with well-developed riparian areas. Influence of livestock grazing and
agricultural use is visible at many locations, and evidence of historic mining activities occurs in the
form of tailings deposits (Chadwick et al., 1997).
Whitewood Creek is classified by the State of South Dakota as warm water permanent fish life
propagation waters in the lower portion (from the Belle Fouche River to Interstate 90) and
coldwater marginal fish life propagation waters from Interstate 90 to the confluence with Gold
Run (South Dakota SL 74:51:03:03). A semipermanent warm water fishery does exist in the
creek (ICF, 1989a) The State of South Dakota has reportedly stocked trout in the upper reaches
of Whitewood Creek. This cold water fishery cannot be established on a permanent basis due to
habitat restrictions (high temperature and low flow) (ICF, 1989a).
It is postulated that the aquatic flora and fauna of Whitewood Creek changed in response to
improvements in the Homestake mine discharge and municipal water treatment in 1984. Some
improvements were effected after completion of biological studies by Herricks (1982), Fox
Consultants, Inc. (1984a), and Goddard (1989). The Herricks (1982) study described a creek
flowing through three ecological zones. The upper third of the creek as a cold, fast-flowing water
with the fish community dominated by cold-water species. The middle third of the creek
(corresponding to the upper half of the 18-mile site reach) was described as a transitional area
where the water becomes warmer, has more pools and riffles providing a transition to more
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warm-water species. The lower third of the creek (corresponding to the lower half of the 18 mile
site reach) runs onto a low-gradient landscape before emptying into the Belle Fourche River and
is dominated by warm-water fish species (Herricks, 1982).
The Belle Fourche River in the study area is relatively wide, low gradient stream, with somewhat
less riparian development. Much of the stream is bordered by farmland and is used as an
irrigation source during summer months.
3.3 Land and Resource Use
3.3.1 Former, Current, and Projected Land Use
The dominant land use within the 100-year floodplain of Whitewood Creek at the time of the
ROD was native woodlands. These woodlands were estimated to occupy about 83% of the total
land area (2,018 acres) within the Whitewood Creek Site (Fox Consultants, 1984a; 1984b). The
remaining land within the Site was used for agriculture and residences. These land use patterns
had remained unchanged for more than 100 years and were not anticipated to change in the
foreseeable future (ICF, 1989a; 1989b). Based on the information obtained during the Site
interviews and inspections, the current and projected land use within the Site have not changed.
3.3.2 Human Use of Resources
At the time of the ROD, residences were scattered along both sides of Whitewood Creek. Based
on 1988 data, 22 households and 5 vacant residential properties were situated within or in close
proximity to the Site with a total population of 85. The population was primarily rural, and
dominated by families who have lived on the Site for 40 years or longer. The land was used for
raising animals and raising crops for animal feed. The water supply sources for these households
and vacant properties varied from shallow and deep wells, County Water Supply District deep
well water and imported water (ICF, 1989a).
Ranches located on or near the Site used groundwater and surface water for stock and irrigation
water supplies with shallow wells serving as the primary source of stock water for 24 ranches.
Deep wells, County Water Supply Districts, ponds, and springs were other sources of stock water
to these ranches.
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The Belle Fourche River (upstream from the Whitewood Creek confluence) is the primary water
source for irrigation of 11 ranches located on or near the Site. Other water sources for irrigation
include the surface waters of Whitewood Creek and shallow or deep well water.
The current and previous use of human resources at the Site are summarized in the following
table. Details on the current residences and water resource use at the Site were not available for
inclusion in the following table. However, these uses are not anticipated to be significantly
different from those reported for 1989.
Resource I so ill (lie W hilewood Creek Sile
lime ol' KOI) IDS'))
Ciirreiil (2001)
Land Use
Woodland Rural
Woodland Rural
(animal and crop production)
(animal and crop
production)
Residences
22
NA
Vacant Residential Properties
5
NA
Household Water Supply Sources
NA
Shallow Wells
10
Deep Wells
7
Butte/Meade Water Supply District
2
Imported Water
3
Stock Water Supply Sources
NA
Shallow Wells
17
Deep Wells
4
Butte/Meade Water Supply District
1
Pond or Spring
2
Irrigation Water Supply Sources
NA
Belle Fourche Irrigation District
5
Whitewood Creek
3
Shallow Wells
2
Deep Wells
1
Source: ICF (1989) NA= Not Available.
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3.4 History of Contamination
3.4.1 Historical Activities that Caused Contamination
Gold Mine Operation
A large gold mine operated by Homestake Mining Company (Homestake) is located in Lead,
South Dakota near the headwaters of Whitewood Creek. During the period between 1870 and
1977, tailings generated during the operation of the mine were released directly into Gold Run
Creek, which flows into Whitewood Creek. Mining operations over the last century produced
about 1,000,000,000 tons of ore from both open pit and subsurface (Fox Consultants, Inc.,
1984a).
The first milling methods at Homestake were primitive and non-mechanized. Gold was recovered
by using crude methods of crushing with recovery by gravity or mercury amalgamation. By 1880,
the early non-mechanical methods were replaced with more than 1,000 stamp mills (large blocks
of cast iron or steel dropped onto replaceable anvils) that crushed the ore to a coarse sand size.
The tailings were then discharged to Whitewood Creek or its tributaries. Prior to the turn of the
century, much of the ore consisted of near surface, red-colored minerals that were residual
oxidation products of the arsenopyrite, pyrrhotite and pyrite mineralization of the original
unoxidized ore bodies (Fox Consultants, Inc., 1984a; Chadwick et al., 1997). After the turn of
the century, the black and green-colored reduced ores from deeper in the mine (below the zone of
oxidation) were the focus of the mining activity. These ores contained large percentages of
reduced oxidation-state minerals, including arsenopyrite and pyrrhotite.
Until 1977 (with the exception of five years of closure during World War II), the "slimes" and
some coarse-grained sands, continued to be discharged directly into Whitewood Creek.
Discharge from a number of sources ceased in approximately 1920, when Homestake became the
only remaining source of tailings discharge. In 1977, Homestake constructed a tailings
impoundment in the upper reaches of the watershed and tailings discharges to the creek ceased
(Chadwick et al., 1997).
Mercury amalgamation of the ores was used over the greater period of the mining operation and
was discontinued in January of 1971. Quotes on the volumes of mercury used and lost to the
waste stream in this process vary from an eighth of an ounce to almost half an ounce per ton of
ore crushed with almost 50 percent of this volume lost to the entire waste stream. Cyanide has
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also been used in the gold recovery process since the early 1900's to process the lower grades of
ore and increase gold and silver recoveries. Since the cessation of mercury use in 1971, cyanide
has been used exclusively for gold recovery, until 1987, when a gravity circuit was added. Since
1987, both cyanide and gravity have been used for recovery. The tailings also contained
considerable quantities of arsenic that is derived from minerals in the ore (Fox Consultants, Inc.,
1984a).
Presently, ore is milled in crushers and rod and ball mills. The material from the milling process is
separated into two size fractions, sand and slimes. These fractions are treated separately by
cyanide leach and carbon filter methods. Residual sand material is used to backfill within the
mine. Residual slimes and process waters are piped to the Grizzly Gulch tailings impoundment in
the upper reaches of the Whitewood Creek watershed. The tailings disposal system became
operational in 1977 resulting in cessation of direct discharge of tailings to Whitewood Creek
(Chadwick et al., 1997).
In 1984 a wastewater treatment plant began treating water from the tailings impoundment and
mine. The plant uses rotating biological contactors to remove cyanide and ammonia; iron
precipitation and sorption to remove metals; and sand filtration to remove suspended solids.
Solids are returned to the tailings pond. Water enters Gold Run Creek that discharges into
Whitewood Creek between the towns of Lead and Deadwood. This discharge is monitored to
meet requirements of the Clean Water Act (Chadwick et al., 1997).
Release and Deposition of Tailings
Tailings, consisting of finely ground rock; residual metallic and nonmetallic compounds not
extracted from the ore and trace compounds used in the extractive processes were transported
away from the mine by the water of Whitewood Creek. The tailings were deposited downstream
from the mine with subsequent deposition along the banks of Whitewood Creek between the
Crook City Bridge and the confluence with the Belle Fourche River (Figure 3-2). The tailings
remain along much of this reach of Whitewood Creek (Chadwick et al., 1997). Reports indicate
that in 1963 as much as 3,000 tons per day of tailings, together with 12,500 tons per day of water
were being discharged to Whitewood Creek (ISSI, 1998; Fox Consultants, Inc., 1984a). Tailings
in Whitewood Creek were also transported downstream into the Belle Fourche and Cheyenne
Rivers (Goddard et al., 1988, USEPA, 1990). Some limited tailings deposits also exist upstream
of the Crook City Bridge (USEPA, 1990).
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Deposition of tailings altered the morphology of Whitewood Creek. Before tailings were
deposited, Whitewood Creek was reportedly a typical Black Hills ephemeral stream with a thin
layer of alluvium deposited over bedrock (ISSI, 1998; USEPA, 1989a). It is estimated that
approximately 25 to 37 million tons of tailings were deposited in the floodplain (ISSI, 1998; ICF,
1989a). The large mass of tailings transported in the Whitewood Creek basin resulted in a series
of depositional and erosional events that distributed tailings throughout the flood plain. In their
upper reaches, Gold Run Creek and Whitewood Creek are rather steep, and most of the tailings
were carried downstream by the flow of the water. Near Crook City, the gradient of Whitewood
Creek becomes less steep, allowing the tailings to become deposited along the banks and in the
creek sediment.
Currently, Whitewood Creek has eroded through the tailings to or near shale bedrock and the
stream is braided over much of the Site area (USEPA, 1989a; ICF, 1989a). When aggradation of
the streambed lessened in the early 1900's, overbank deposits were stabilized in places with
vegetation (USEPA, 1989a).
The Feasibility Study (FS) (ICF, 1989a and 1989b) describes the stratigraphy of the tailings
deposit areas as: 1) an upper deposit of tailings ranging from approximately one to fifteen feet
thick and 50 to several hundred feet wide on each side of the creek along its full 18 mile length
within the site, 2) an underlying strata of natural alluvium consisting of sandy to sandy silt
materials with variable amounts of intermixed tailings, and 3) the thick shale strata that forms the
floor of the valley.
3.4.2 Site Contaminants and Risks
This section discusses the contaminants of concern for the NPL listing, the Remedial
Investigations the results of the risk assessments completed prior to the ROD and the
determination of the primary health threat at the Site.
Elements of NPL Listing
The hazardous substances of concern considered in the Hazard Ranking Score (HRS) for the
Whitewood Creek site were arsenic, copper, zinc, selenium and mercury. Groundwater and
surface water were the two release pathways of concern (USEPA, 1994).
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Contaminated Media
The contaminated media at the Site include tailings deposits, alluvial materials underlying tailings
deposits, surface soil, groundwater in the downgradient alluvial aquifer, surface water and
vegetation (USEPA, 1990).
The tailings are the major source of the contamination found in other affected media at the Site
(USEPA, 1990). Tailings are slowly released into the alluvial aquifers at the Site and transported
into the alluvium underneath the tailings deposits. Some of the tailings and their contaminants are
released into the surface waters of Whitewood Creek through seepage from tailings and alluvium,
erosion of tailings along the creek bank, and heavy rains or periodic flooding. Vegetation
growing on tailings deposits contain concentrations of chemicals associated with tailings.
Contaminants are transferred into the downgradient alluvial aquifer during the wet periods of the
year when the water table rises to be in contact with the tailings and the slow dissolution and
infiltration of chemicals downward through the tailings into the groundwater. Portions of the
surface soils of croplands irrigated with waters from Whitewood Creek are impacted by chemicals
associated with tailings. Surface soils at residences are impacted by windblown tailings, transport
of tailings during flooding or the import of tailings materials for use as a soil conditioner or
driveway base (USEPA, 1990).
Results of Risk Assessments Prior to the ROD
Several studies (Fox Consultants Inc., 1984a and 1984b; Environ Corp, 1985; ICF, 1989c;
USEPA 1989a; Jacobs 1989) have been conducted that evaluate potential human health and
environmental impacts at the Site. The Fox study (Fox Consultants, Inc., 1984a and 1984b) was
concluded by USEPA to constitute the functional equivalent of a remedial investigation for the
Site (USEPA, 1990). The USEPA (1989a) and Jacobs (1989) studies were used as the basis for
the remedial action objectives for the Feasibility Study (USEPA, 1990). The findings of each
study are briefly summarized below.
Fox Consultants. Inc. (1984b")
As part of the Phase II Study, Fox Consultants, Inc. (1984b) examined the data collected in the
Phase I Study (Fox Consultants, Inc., 1984a) and evaluated the impacts of fourteen target
substances including arsenic, cadmium, iron, lead, chromium, manganese, mercury, zinc, sulfate,
selenium, copper, cyanide, silver and nickel in environmental media. The environmental media
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examined included vadose zone water, groundwater, surface water, soil, irrigated crops, natural
vegetation, fish and aquatic invertebrates.
The study reported that arsenic, sulfate, selenium, cadmium, copper, cyanide and pH posed an
environmental concern to one or more of the environmental media examined. Specifically,
arsenic, selenium and sulfate were of concern in groundwater. Arsenic, cadmium, copper and
cyanide were of environmental concern in surface water. Arsenic was additionally of concern in
both soil and native vegetation.
The report concluded that of the substances considered to be of environmental concern, arsenic
was the most significant throughout the environmental media evaluated.
Environ Corp (1985")
Environ Corp (1985) evaluated potential impacts to human health from gold mine tailings in the
18-mile area of Whitewood Creek. Exposures to eight chemicals associated with mine tailings
(arsenic, cadmium, copper, cyanide, iron, manganese, mercury and silver) were evaluated for
adult and child residents living within the Whitewood Creek floodplain. Adults were evaluated
for exposure by ingesting contaminated groundwater and fish. In addition to the pathways
evaluated for an adult resident, child residents were also evaluated for exposure through ingestion
of tailings impacted soil. Estimated daily intakes of arsenic, cadmium, copper, cyanide and
mercury were below the Acceptable Daily Intakes (ADIs), and concluded to not pose a risk to
human health. Although the estimated daily intakes of iron for both adults and children and
manganese and silver in children exceeded the ADIs for the respective chemicals, they were
concluded unlikely to pose adverse health risks. The study concluded that exposures to chemicals
associated with the mine tailings were very unlikely to pose significant adverse risks to human
health.
ICF 0989c)
ICF (1989c) summarizes the baseline assessment of potential health impacts used for the
Feasibility Study (FS). The study evaluated potential human health threats to persons living
within the Site from consumption of elevated levels of chemicals in shallow groundwater used for
drinking water , incidental ingestion of surface soils and consumption of food items (milk,
vegetables, meat, eggs, fish) produced within the Site. Potential cancer risks from arsenic and
potential non-cancer risk from arsenic, cadmium, chromium, copper, lead, manganese, mercury,
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nickel and selenium were evaluated. Potential risks were calculated for both "typical-case" and
"potential worst-case" exposure scenarios. The study found that arsenic in surface soils and
irrigated croplands may present potential cancer risks to human health and that arsenic in shallow
groundwaters within the Site appeared to produce potential carcinogenic risks that are higher than
those normally deemed acceptable under CERCLA. However, the study noted that potential
cancer risks from arsenic may have been overstated due to uncertainties associated with arsenic
availability in soils and the reduced soil ingestion during winter months when the ground is frozen.
Other chemicals associated with the tailings were concluded to not pose any unacceptable threats
to human health from tailings, agricultural soils, shallow groundwater and surface water within
the Site.
usEPAqgsga^)
A preliminary Endangerment Assessment (EA) of the Whitewood Creek site was completed by
Battelle Pacific Northwest Laboratory (PNL) for the USEPA Office of Health and Environmental
Assessment. The study evaluated potential impacts to public health, aquatic species and terrestrial
species from hazardous substances associated with the Site. Human health risks from exposure to
arsenic, cadmium, chromium, copper, lead, manganese, mercury, nickel and selenium were
evaluated at six ranches along Whitewood Creek. Risks to an adult resident exposed by
inhalation of suspended tailings, incidental ingestion of soil, ingestion of groundwater, and
ingestion of locally grown food items were evaluated. Risks to children were evaluated from the
incidental ingestion of soil. Both typical (average) intakes and worst-case (high end) exposure
assumptions were used in the risk evaluations. Adult resident cancer risks from arsenic were
greater than 1E-04 for both typical and worst-case exposure scenarios. Cancer risks to a child
resident from the incidental ingestion of arsenic in soil were greater than 1E-04 at 3 of the 6
residential sites evaluated under the typical exposure scenario, and greater than 1E-04 at all 6
residential sites based on worst-case exposure assumptions. The total Hazard Index (HI) for
non-cancer risks to adult residents from all chemicals were greater than 1 under both typical and
worst-case exposure scenarios.
Although the EA primarily focused on evaluation of human health risks, ecological impacts to
terrestrial and aquatic receptors were also evaluated. The EA evaluates potential ecological
impacts from ten metals, including arsenic, cadmium, chromium, copper, lead, manganese,
mercury, nickel, selenium and silver.
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Impacts to Terrestrial Receptors
A limited assessment of impacts to terrestrial receptors was conducted based on historical studies
and metal concentrations in vegetation and soil. Historical studies (Bergeland et al. 1976; Hesse
et al. 1975; Tveidt, 1981) have documented potential impacts of Site related chemicals on
terrestrial animals within Whitewood Creek. Hesse et al. (1975) reported mercury levels in
double-breasted cormorants in fish-eating birds in the Cheyenne River, downstream of
Whitewood Creek and the Belle Fourche River, that were significantly greater than concentrations
observed in a control population from the Missouri River System. Cattle deaths and sickness
attributed to arsenic toxicosis have been documented within the Whitewood Creek floodplain
(Bergeland et al. 1976) and downstream of Whitewood Creek along the Belle Fourche River
(Tveidt, 1981).
Potential impacts to terrestrial wildlife from the consumption of vegetation were hypothesized
based on native vegetation and irrigated crop samples collected during the Phase I Investigation
(Fox Consultants, Inc. 1984a). Samples were compared with levels known to impact both plants
and animals. Cadmium concentrations in irrigated crops were at a level reported to cause adverse
effects in some animals. Mercury and arsenic concentrations were at levels that may affect
livestock and arsenic-sensitive animals.
Although chemical concentrations in soils or vegetation indicated possible impacts to terrestrial
wildlife along Whitewood Creek, data on metal concentrations in animal tissues correlated with
plant and soil concentrations were not available. Therefore exposures were difficult to quantify
and impacts difficult to rigorously address.
Impacts to Aquatic Receptors
Both a screening analysis and quantitative assessment of potential impacts to aquatic ecosystems
were conducted. Total recoverable concentrations measured by USGS (1985) were compared to
USEPA acute and chronic ambient water quality criteria (AWQC) for the protection of aquatic
life. The results of this screening analysis showed six constituents (arsenic, cadmium, copper,
lead, mercury and silver) had geometric mean concentrations higher than respective chronic
AWQC values. These same six constituents plus zinc had maximum detected concentrations
exceeding respective acute AWQC values. Based on the screening results, a more quantitative
assessment was performed that examined the relationships between location, aquatic species,
constituent speciation and phase, water quality characteristics, duration of exposure and
3 - 13
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toxicological criteria. The results of these analyses indicated the potential for unacceptable
adverse effects to aquatic species. Elements of most concern were copper, and cyanide.
Elements of moderate concern were cadmium, iron, mercury and silver. Lead and nickel were of
minor concern. Arsenic, chromium, selenium and zinc were of no concern.
Jacobs (1989^)
The EA for the Whitewood Creek site was finalized by Jacobs Engineering Group Inc. for
USEPA Region VIII in July 1989 (Jacobs, 1989). The final EA was based on information in
USEPA (1989a) and Subsection 1.7 of the Preliminary Draft of the FS prepared by ICF
Technology in April of 1989 (ICF, 1989c). Jacobs (1989) examined the potential human health
threats to Site residents from elevated levels of chemicals associated with the mine tailings.
Potential cancer risks from arsenic and potential non-cancer risk from arsenic, cadmium,
chromium, copper, lead, manganese, mercury, nickel and selenium were evaluated in groundwater
and surface soils. Cancer and non-cancer risks were calculated for an adult resident exposed to
chemicals in surface soils (residential soil, irrigated cropland, tailings areas) and groundwater from
the upgradient alluvial aquifer. Risks to a child resident were evaluated for exposure from
residential soils and groundwater from the upgradient alluvial aquifer. Risks to a recreational
visitor were evaluated from exposure to surface soil. The study concluded that ingestion of
contaminated groundwater and surface soils are significant pathways that contribute to health
risks at the Site. Cancer risks to adult residents from arsenic were one order of magnitude greater
than the cancer risks at a reference site. No potential adverse non-cancer effects were predicted
for adult residents. Potential adverse non-cancer health effects were predicted for children from
incidental ingestion of Site soils. No adverse cancer or non-cancer risks were predicted for a
recreational site visitor.
Primary Health Threat Identified in ROD
The primary health threat identified in the ROD for potential harm to human health and the
environment was exposure to arsenic-rich tailings deposits, alluvial soil, residential soil and
alluvial groundwater contaminated with arsenic (USEPA, 1990).
Human Health
Concentrations of arsenic exceeded background levels and resulted in an unacceptable risks to
current and future Site residents (USEPA, 1990).
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Ecological Risk
Dissolved arsenic concentrations in Whitewood Creek approached the ambient water quality
criteria established by USEPA for the protection of aquatic life. Since arsenic levels in surface
water were not exceeded, the ROD assumed that the aquatic habitat was not threatened or
endangered. Some native plants were found to have arsenic concentrations greater than the
reference area. However, arsenic was determined to be one of many factors, such as other
minerals, clay content, soil pH and permeability) limiting the establishment of a normal plant
community (USEPA, 1990).
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4.0 REMEDIAL ACTIONS
4.1 Remedy Selection
The only ROD for the Whitewood Creek Superfund Site was signed on March 30, 1990 and
addressed arsenic contaminated soil in residential areas (USEPA, 1990). The remedial action
objectives identified and outlined in the ROD are:
Prevent ingestion by Site residents of surface soils from the tailings deposit areas
and from other areas within the Site that when combined would pose a potential
excess lifetime cancer risk from intake of arsenic that would exceed 1E-04.
Prevent ingestion, by site residents, of residential surface soils having an average
arsenic concentration that exceeds 100 mg/kg.
Prevent ingestion, by site residents, of drinking water drawn from the
downgradient alluvial groundwater having an average concentration of any
inorganic constituent other than selenium that exceeds the Maximum Contaminant
Level (MCL) for that constituent specified in the National Primary Drinking Water
Regulations.
Continue monitoring the water quality and flow of Whitewood Creek at the
sampling stations near Whitewood and Vale.
The site is managed as a single operable unit. However, the remedy has been implemented in two
phases: remediation of contaminated soils in existing residential areas (Phase I) and the
implementation of institutional controls to limit access to tailings and groundwater (Phase II).
The remedial actions at the Whitewood Creek Site include:
Cover and/or remove soils in the existing residential areas containing arsenic levels
of 100 mg/kg or greater. Dispose of contaminated materials removed during this
activity in an off-site disposal facility.
Restrict future development in the 100-year floodplain and tailings deposits as
provided through county ordinances regulating land use.
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Prohibit excavation of tailings deposits for other uses and prohibit excavation of
remediated areas through county ordinance, however, mining would be allowed
subject to the regulations of the State of South Dakota.
Refine knowledge of the extent of contamination and delineate the 100-year
floodplain. Provide detailed maps to define Site boundaries and specify activities
to support county ordinances.
Set up an educational program to inform people about hazards presented at the
Site and ways to decrease their personal exposure.
Continue enforcement of the ban on installation of water supply wells within the
100-year floodplain (this is already prohibited by a state regulation).
Continue monitoring the surface waters of Whitewood Creek for significant
releases of hazardous substances.
Resample remediated residential areas after major flood events.
As a result of information obtained during remedial design activities, an Explanation of Significant
Differences (ESD) to the remedy outlined in the ROD was issued on June 11, 1991. The ESD
identified one change and one clarification to the original remedy:
Contaminated materials removed from residential areas during remediation would
be disposed of in an on-site facility instead of an off-site facility.
The term "existing residential areas" was defined to refer to areas within the Site
where residential land use is occurring as of the effective date of county land use
ordinances. This term was not explicitly defined previously and was used in the
ROD to describe those areas of the Site which would undergo soil cleanup as part
of the Remedial Action.
New information on the quantities of contaminated materials to be disposed of during the
remedial action were identified during remedial design activities. Based on discussions with Site
residents regarding their land use habits, smaller areas around each home (i.e., high use areas)
4-2
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were identified for remediation. The quantity of material to be disposed of was less than 10,000
cubic yards, less than one-third of the material estimated for disposal during the development of
the ROD (30,000 cubic yards).
4.2 Remedy Implementation
The remedy was implemented in two phases: remediation of contaminated soils in existing
residential areas (Phase I) and the implementation of institutional controls to control access to
tailings and groundwater (Phase II).
4.2.1 Residential Remediation
The remedial design for the site was started August 1990 by FMG, Inc.. Homestake, with
USEPA oversight, conducted sampling to identify and characterize soil contamination at 31
residences. Twenty-seven residences were identified with soil arsenic concentrations above the
100 mg/kg action level, and thus required remediation. Eleven of the 27 sites with arsenic
concentrations above the action level were removed from the scope of the remediation program.
The homes were rendered "uninhabitable through voluntary demolition or removal of the housing"
(USEPA, 1993). Thus, remedial activities occurred at 16 residences or individual sites.
Residential remediation activities included removing and/or covering the soils from gardens, yards
and driveways that were above the 100 mg/kg action level for arsenic. The objective of the
remedial activities was to have 24 inches of clean topsoil in garden areas, 12 inches of clean
topsoil in yards, and 6 inches of clean gravel in road and driveway/parking areas. Fill materials
imported into the individual residential sites consisted of topsoil, gravel, trees, shrubs, sod,
fencing and other miscellaneous debris, many of which were obtained from residential properties
within the Site. The majority of the clean topsoil fill materials were obtained from the Keith Silt
Loam soils located on the Phillip Bestgen property. Clean gravel fill materials were primarily
obtained from the Bestgen property. Clean fill material was stockpiled at the Topsoil and
Topsoil Subgrade Borrow Site (FMG, Inc., 1992).
A pilot scale remediation project at the Marrs Residence began in September 1991 and was
completed by October 1991. Construction was temporarily halted for the winter. Remediation of
the remaining 15 residences/sites was completed during the period of May 6, 1992 through
September 15, 1992. Table 4-1 summarizes the construction dates and the type and quantities of
materials removed from individual properties during residential remediation activities at the Site.
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A Temporary Stream Crossing was constructed across Whitewood Creek to limit traffic across
the existing low load capacity bridge (FMG, Inc., 1992). Two 48-inch diameter corrugated metal
pipe culverts were installed into the creek during the late summer, low flow periods. Pipes were
backfilled with 2 to 6 inch diameter gravel which was used as a road base.
Construction of the on-site disposal facility began on September 30, 1991. The Disposal Site was
built on property owned by the Whitewood Venture encompassing approximately 32 acres.
About 7.0 acres of this property would be used for disposal of materials. The disposal area was
located on an overbank deposit of mine tailings with surface arsenic concentrations ranging from
850 mg/kg to 10,000 mg/kg. No sub-grade preparation of the area was performed, in order to
minimize disturbance of the tailings.
Materials removed from the residential sites (contaminated gravel, topsoil, trees, shrubs, sod, and
other miscellaneous debris) were transported to the disposal site and placed at the locations
specified in the Transportation and Disposal Plan. Wastes were segregated into separate areas of
the Disposal Site during materials placement activities. Fences, trees and other debris from the
residential areas removed during construction and remediation would be disposed of adjacent to
the fill area of contaminated materials. During residential remedial activities, approximately 4,430
cubic yards of waste materials were placed at the on-site disposal facility. Additional work at the
disposal site included constructing an access road, placement of Rip-Rap, constructing a fence
around the site, and hydroseeding the surface of the disposed soils.
Disposal Site construction was completed on September 30, 1992. Figure 4-1 is an "as
constructed" diagram of the disposal site detailing the top soil and tree disposal areas. Figure 4-2
is a post-construction photo of a soil disposal cell within the disposal site. Whitewood Creek is
visible in the upper left portion of the photo.
Pre-final inspections of the overall site were conducted by the USEPA and State of South Dakota
on September 22, 1992. Punch list items from the inspection included disposal site revegetation,
erosion control measures and minor landscaping at an individual site. The final inspection of the
overall Whitewood Creek Site was conducted on November 12, 1992. All punch items were
satisfactorily completed (USEPA, 1993).
On December 21, 1992, USEPA approved the Construction Completion Report for Remedial
Action Activities at the Site. This report was submitted by Homestake and certified by a
registered professional engineer that the remedy was operational and functional (USEPA, 1993).
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The Preliminary Close-Out Report was signed on September 25, 1992. The completion of the
residential remedial action at Whitewood Creek Superfund Site was certified by USEPA Region
VIII on March 31, 1993.
Modifications to the Specifications of the ROD for Residential Remediation
During the Remedial Design and Remedial Action, modifications or changes to the specifications
in the ROD were made in addition to those previously described in the ESD. The changes were
made with USEPA approval and are described below (USEPA, 1993):
Design Sampling Approach. The ROD specified that any 900-square-foot area sampled
and determined to exceed the 100 mg/kg arsenic level would be subject to remediation.
This approach was applied to 27 of the sampled properties. Homestake developed a
statistical approach for evaluating the sampling results of the final four properties and for
future verification sampling. This approach established a representative population within
the grid. Determination of the need for remediation was based on statistical evaluation of
the sample results of the representative population as outlined in the Final Sampling and
Analysis Plan. The USEPA guidance document "Methods of Attainment of Cleanup
Standards" was referenced in development of the approach.
Maximum Allowable Arsenic Concentration in Replacement Fill. The ROD specified that
clean imported soil or gravel contain less than 20 mg/kg arsenic. This criteria was
changed during the remedial design to 20 mg/kg +/- 10 mg/kg following evaluation of
actual background concentrations of arsenic in the native soils. Soil samples collected
during Remedial Design activities indicated that background arsenic concentrations were
potentially higher than 20 mg/kg.
Final Confirmation Sampling Elimination. Confirmation soil samples were required by the
ROD to be collected following remediation of residential properties to verify that arsenic
levels were below 100 mg/kg. However, USEPA determined that this sampling would be
a redundant check to ensure action levels had been achieved and eliminated this
requirement. This change was justified because extensive pre-construction arsenic
sampling was conducted on soil materials to be used as replacement fill during
remediation. This sampling effort was conducted in accordance with the Final Sampling
and Analysis Plan. Independent construction observers, representing both USEPA and
Homestake, were on-site throughout Remedial Action to ensure that previously sampled
4-5
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materials were used as replacement fill. Homestake conducted additional sampling,
beyond that required by the design plans. One sample was collected for every 15
truckloads of fill material.
Difficulties and Unexpected Site Conditions for Residential Remediation
The following difficulties and unexpected Site conditions were encountered for each of the Phases
of the remediation.
Residential Remediation. During Residential Remediation Activities, some observations
were made that would improve remediation and several situations were encountered that
required changes to the individual residential remedial plans . These changes included:
Additional testing for total arsenic was performed on the fill materials imported to
all Individual Sites to provide additional assurance of the imported material quality. The
Field Construction Observer sampled fill materials at a frequency of approximately every
15 truckloads (FMG, Inc., 1993).
Requests for additional work by residents at their property associated with remedy
implementation. (For example, rocks were hand picked out of the top soil material
being replaced at the Holsclaw property, at the request of the owner).
One ongoing problem was identified during remediation activities at the Nelson Residence:
Removal of construction staking by cattle in the area. FMG, Inc. replaced the
staking on June 16, 1992, however this problem plagued the construction
operations during the entire period (FMG, Inc., 1993).
Construction of Disposal Site. No problems or issues were identified during the
construction activities of the Disposal Site, fill material placement area or temporary
stream crossing (FMG, Inc., 1993). Several changes to the plans and specifications for the
Disposal Site and Temporary Stream Crossing were approved by USEPA and
implemented during the construction phase of the project, including:
Elimination of rip-rap by the creeks' edge at the Disposal Site.
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Addition of rip-rap at the downstream end of the fill materials placed in the canal.
Approval not to abandon the wells at the Disposal Site.
Changing the location of the fence line surrounding the Disposal Site.
Construction of Topsoil and Topsoil Subgrade Borrow Site. No problems or issues were
identified during the construction activities of the Topsoil and Topsoil Subgrade Borrow
Site (FMG, Inc., 1993). USEPA approved one change to the plans and specifications for
the Topsoil Borrow Site:
Reseeding the Topsoil and Topsoil Subgrade Borrow Site at the request of the
property owner.
Construction of Temporary Stream Crossing. No problems or issues were identified
during the construction activities of the Temporary Stream Crossing (FMG, Inc., 1993).
Several changes to the plans and specifications for the Temporary Stream Crossing were
approved by USEPA and implemented during the construction phase of the project,
including:
Substitution of 2 to 6 inch diameter rock as fill materials for the channel portion of
the temporary stream crossing and as the road surfacing for the crossing (in lieu of
a geotextile and 6 inch thick layer for gravel surface coarse material).
Removal of taller trees and shrubs from the overbank areas of the temporary
stream crossing.
Using existing soils and low vegetation as the road surface.
Elimination of installing 1 to 2 foot diameter rip-rap materials at the Temporary
Stream Crossing for erosion control.
Limited operation of equipment into the water for installation and removal
operations at the Temporary Stream Crossing.
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Straw bale installation at the Temporary Stream Crossing to limit silt and
sediments entering the creek from construction activities.
Eliminating the requirement of revegetating the Temporary Stream Crossing (at
the request of the property owner) past hydroseeding the site.
4.2.2 Institutional Controls
The institutional control phase of the remedy includes the implementation of both traditional,
legal, land use restriction controls as well as other institutional control items, such as an annual
educational program. These components of the remedy are designed to control ingestion of
surface soils/tailings and prevent ingestion of downgradient alluvial groundwater. The
Institutional Controls for the Site include the following:
Identification and mapping of the tailings deposits, tailings impacted soils,
and the 100 year flood plain.
Enacting land use ordinances restricting future development in Butte,
Meade and Lawrence Counties that:
Prohibit commercial and residential buildings on the tailings deposits and
limit residential development to areas that have less than 100 ppm arsenic
in the surrounding soil.
Prohibit excavation of the tailings deposits except for mining projects
permitted by the State of South Dakota and restrict excavation below
remediated areas where covered soils have greater than 100 ppm arsenic.
Continue enforcement of the South Dakota shallow well ban in the
Whitewood CreeklOO year floodplain.
Conduct an annual educational program to inform people of the hazards
associated with the Site and ways to decrease personal exposure.
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Resample remediated residential areas impacted by flooding of Whitewood
Creek, if soil arsenic levels are above 100 mg/kg.
Monitor the surface waters of Whitewood Creek.
Several of these institutional controls will be ongoing operation and maintenance activities, such
as long-term surface water monitoring, distribution of educational materials to Site residents, and
resampling of flooded areas. Homestake will conduct these activities for a period of at least 30
years following completion of Site remedial activities.
On February 13, 1995, USEPA certified that Homestake had performed in accordance with the
consent decree the remedial action at the site, except for continuing obligations (i.e., operation
and maintenance activities), enumerated in paragraph 99 of the decree and accepted the
Institutional Controls Completion Report for the Site (USEPA, 1995).
Extent of Contamination and Delineation of 100 Year Floodplain
The tailings deposit boundary, tailings impacted soils boundary and the 100-year floodplain
boundary were determined by extensive field programs beginning the summer of 1991 and ending
the fall of 1992. The detailed maps (Figure 4-3) for these boundaries were approved by USEPA
April 15, 1993 (WDC, 1994a). These boundary determinations were the first step towards
enacting county land use ordinances.
Future Development Restrictions
Butte, Meade and Lawrence County Land Use Ordinance Enactment
During 1993 and 1994, Butte, Meade and Lawrence Counties adopted ordinances prohibiting
construction of new residential or commercial structures on the tailings deposits, restricting future
development in tailings-impacted areas of the Site, and prohibited removal and use of tailings
from outside the tailings areas. A county building permit handbook (Attachment 4-1) was
developed to aid in the future implementation of the proposed ordinances, and approved by
USEPA on November 29, 1993. The handbook defines the steps necessary for residential
development of the tailings impacted areas (Figure 4-4) (WDC, 1994b). The following table lists
the dates of the county meetings where discussions of and the formal adoption of these ordinances
occurred.
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County Meetings for l-'ormal Adoption ol'Ordinances
l-'irsl Reading
2nd Reading and
Adoption
Butte County
December 15, 1993
January 12, 1994
Lawrence County
December 8, 1993
January 4, 1994
Meade County
January 4, 1994
February 1, 1994
State Well Ban Regulation
A state regulation restricting the construction of wells within the 100 year floodplain of
Whitewood Creek (ARSD 74:02:04:26), remains in place. The regulation has a provision that
allows variances to be granted by the State's Chief Engineer for the construction of wells within
the floodplain, if wells are constructed to prevent contamination from the tailings deposits and will
not cause groundwater pollution. The state well ban regulation is included as part of the county
building permit handbook (Attachment 4-1) for development activities within the Site.
Annual Education Program
In 1993, Homestake began distributing an annual fact sheet to educate the public on Site hazards
and ways to minimize risks from residual contamination (USEPA, 1994). Educational materials
were distributed annually to residents during the first quarter of each year from 1993 through
2001. Some of these materials are provided as Attachment 4-2.
Surface Water Monitoring Program
The surface water monitoring program was implemented in May of 1993 to evaluate the effect of
unknown rates of release of arsenic from the tailings. Surface water samples have been collected
four times annually from two United States Geological Survey (USGS) gauging stations from
May 1993 to present. The first USGS station (06436180,Whitewood Creek above Whitewood)
is located downstream of the confluence of Whitewood Creek with Gold Run. The second USGS
sampling station is 06436198 (Whitewood Creek Above Vale). Sampling times occurred (1) in
late winter before major snow-melt runoff; (2) during peak runoff in the spring; (3) during the low
flow period in late summer; and (4) once immediately following a major precipitation event
(Addendum B to WDC, 1994b).
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Arrangements were made between Homestake and the USGS, Water Resources Division, South
Dakota District Office, Rapid City, South Dakota for the USGS to collect the surface water
samples. USGS provided the services for collection of the surface water samples and the analyses
of these samples in USGS laboratories (WDC, 1994b).
Residential Flood Monitoring
A program was established for the monitoring of the residential areas along the creek that have
the potential to be re-contaminated by the redistribution of contaminants during flooding events.
Monitoring and procedures for sampling and remediating re-contaminated areas under this plan
are specified in the O&M Plan (WDC, 1994b).
Modifications to the Specifications of the ROD for Institutional Controls
Changes and modifications to specifications in the ROD were made during implementation of the
institutional control phase of the remedy. These changes were approved by USEPA and are
described below (USEPA, 1993):
Ordinance restrictions on future digging in remediated areas. The remedy outlined in the
ROD required counties to adopt ordinances that restrict future digging in areas that have
been previously remediated. Information from sampling programs and a negative
community response to this restriction prompted the deletion of this requirement. This
modification to the ordinances was approved by USEPA in a letter dated November 29,
1993.
Removal of construction of public works projects on tailings provision from ordinances.
To meet a need expressed by the City of Whitewood during ROD development, the ROD
provides for the construction of public works projects on the tailings after remediation to
be included in the county ordinances. In a letter dated November 8, 1993, the City of
Whitewood stated that they no longer had a need for this provision. USEPA approved the
deletion of this provision in a letter dated November 29, 1993.
Change in reviewing agency for future house sites. The South Dakota Department of
Natural Resources was identified to be the reviewing agency for sampling and remediation
plans for future house sites in tailings impacted areas. The USEPA, State and local
community determined that this program would be more effectively administered at the
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county level, and to rely on the State DENR for technical support as requested by the
county. USEPA approved this modification in a letter dated November 29, 1993.
Difficulties and Unexpected Site Conditions for Institutional Controls
No difficulties were identified in the Institutional Controls Completion Report (WDC, 1994a)
with the implementation of this portion of the remedy at the Site.
4.3 Operation and Maintenance
The Operation and Maintenance (O&M) activities outlined in the Post Closure Operations,
Maintenance, and Reporting Plan (WDC, 1994b) for the Whitewood Creek Site include:
Surface Water Monitoring at two USGS stations on Whitewood Creek
Annual Site Resident Education Program
Future Development Restrictions - Annual Review of Building Activity
Post-closure Residential Site Soil Sampling Activities and Remediation
Flood Impact Soil Sampling at Remediated Residences
Five-Year Review Remedial Action Verification Soil Sampling
Residential Soil Remediation (as necessary)
Disposal Site Monitoring
Reporting
4.3.1 Surface Water Monitoring
The ROD requires continued monitoring of Whitewood Creek surface water quality to evaluate
the effect of unknown rates of release of arsenic from the tailings deposits. Samples are to be
collected four times a year at the two USGS sampling stations on Whitewood Creek near the
towns of Whitewood and Vale.
System O&M Requirements
The surface water sampling plan is provided as Addendum B to the O&M Plan (WDC, 1994b).
The plan specified that surface water samples were to be collected four times a year at two USGS
sampling stations on Whitewood Creek. Water samples were to be analyzed for dissolved and
total recoverable arsenic as well as pH (hydrogen ion content), specific conductance (SC) and
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total suspended solids (TSS) for the purpose of assessing additional information that may impact
the mechanics of arsenic occurrence in Whitewood Creek. Flow measurements were are also to
be recorded (Addendum B to WDC, 1994b).
The ROD specified that surface water samples were to be collected during four time periods
throughout the year, representing:
(1) late winter before major snow-melt runoff
(2) peak runoff in the spring
(3) the low flow period in late summer
(4) once immediately following a major precipitation event
Based on historical flow data from the two USGS Gauging Stations within the Site, the most
appropriate months and/or conditions for sampling are expected to be (Addendum B to WDC,
1994b):
(1) December - for late winter flow prior to major snow-melt runoff
(2) May - for peak run-off flow in the spring
(3) September - for late summer low flow
(4) Major precipitation event - 0.23 inches of rain or more during a 24-hour period.
USEPA Region VIII provided the criteria for determining a major precipitation event as an event
that equals or exceeds 0.23 inches of rain in a 24 hour period. The Water Quality Sampling Plan
(Addendum B to WDC, 1994b) states that local landowners in the Site area will be contracted to
notify sampling personnel of a local rain event that equals or exceeds the criteria (0.23 inches
during a 24 hour period). The major precipitation event water sample will be collected within 36
hours of the initial notification.
The Water Quality Sampling and Analysis Plan (Addendum B to WDC, 1994b) recommends, to
the degree that weather and sampling conditions allow, that the surface water samples be
collected during any given month in an upstream-to-downstream sequence. The sampling data
are included in quarterly O&M reports to USEPA, as the data are available.
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System Activities to Date
Surface water quality monitoring commenced in May of 1993. The following table summarizes
the water quality monitoring data submitted by Homestake in its Quarterly Reports to USEPA.
Surface water samples were collected on the following dates:
Summary of Surface Water Monitoring Samples Collected at Two USGS
1993
12/27/1993
-
9/9/1993
5/6/1993
1994
12/20/1994
4/21/1994
9/1/1994
4/21/1994
1995
-
5/24/1995
8/30/1995
5/8/1995
1996
1/8/1996
5/8/1996
8/20/1996
5/25/1996
1997
1/7/1997
5/7/1997
8/26/1997
-
1998
12/16/1998
4/28/1998
9/2/1998
6/9/1998
1999
12/29/1999
5/5/1999
9/13/1999
6/3/1999
2000
-
-
6/16/2000
4/26/2000
2001
1/24/2001
5/2/2001
9/13/2001
6/6/2001
Problems Encountered
No major problems were encountered in the implementation of the surface water monitoring
program. Seasonal variations and outside circumstances resulted in only three of the four types of
samples being collected during 1993, 1994, and 1995:
Three of the four sample types were collected during 1993. Snowmelt and high
flow had already occurred when the monitoring program began in May of 1993.
Thus, a high flow sample was not collected during this sampling year. Total
suspended solids were not collected during the major precipitation event of 1993.
The routine sampler was on vacation and the replacement personnel did not collect
the TSS sample.
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A sample was not collected during a major precipitation event in the summer of
1994. Thus, the high flow sample collected on 4/21/94 was used to represent both
high flow conditions and a major precipitation event.
Only three samples were collected during 1995. The winter low flow sample for
1995 was not collected in December, due to the partial government shutdown.
The sampling personnel were considered non-essential federal government
employees and were unable able to work during the partial shut down.
A flow measurement was not reported at USGS Station 06436180 during the 1995
major precipitation event. However, this information is available for download
from the USGS website.
A major precipitation event sample was not collected during 1997. However, two
late winter samples were collected. Explanations for theses deviations from the
Surface Water Monitoring Plan were not available from the Monthly or Quarterly
reports reviewed.
Late winter and high flow samples were not reported during 2000. However, two
low flow samples were collected. Explanations for theses deviations from the
Surface Water Monitoring Plan were not available from the Monthly or Quarterly
reports reviewed.
4.3.2 Annual Site Resident Education Program
The ROD requires an annual site resident education program to acquaint Site residents with the
potential health hazards associated with exposure to the tailings soils and downgradient alluvial
groundwaters within the Site, and methods for minimizing incidental ingestion of contaminated
materials. The education program is additionally prescribed to inform potential property owners
of potential health hazards.
Homestake is to annually distribute educational materials to Site residents.
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System O&M Requirements
An informational package must be distributed to landowners within the Site on an annual basis.
The package shall include a discussion of the EPA's established risks associated with the tailings
and tailings impacted soils. The scope of the remedial action program will be outlined and a
compilation of the land-use restrictions and discussion of the intent of these ordinances will also
be discussed. A list of personal precautions to limit exposure must also be drafted. Individual
maps will be provided to each landowner to aid in their understanding of the areas affected by the
EPA's risk calculations.
System Activities to Date
The educational mailing program was initiated in 1993, and generally takes place during the first
quarter of each year. The following table documents the dates that the annual educational
mailings were sent to Site residents, as recorded in Homestake's Quarterly and Monthly Reports.
Copies of these materials are included in this report as Attachment 4-2.
Aniuiiil Silo Resident 1'«Iiic;i 1 ion;i 1 Pro^mm M;iilin^s
Yciir
l);Me of Mailing
Source
1993
4/8/93
HMC, 1993i
1994
2/28/94
HMC, 19941
1995
2/14/95
HMC, 1995g
1996
2/21/96
HMC, 1996c
1997
4/97
HMC, 1997c
1998
first quarter 1998
HMC, 1998a
1999
February 18, 1999
HMC, 1999c
2000
date not available
Ted Fellman, USEPA
2001
5/30/01
HMC, 200Id
NA= Information not available in the quarterly reports reviewed
As demonstrated in Attachment 4-2, the content of these annual educational mailings does appear
to vary from year-to-year.
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Problems Encountered
Based on a review of Site Monthly and Quarterly Progress Reports, no problems relating to the
implementation of the Annual Educational Program were identified.
4.3.3 Future Development Restrictions-Annual Review of Residential Building Activity
One institutional control implemented as part of the remedy was to limit exposure to tailings by
restricting development within the Site. Development on the tailings deposits is prohibited by
county ordinances. Residential development within the tailings impacted area is allowed on
locations that have arsenic concentrations of 100 ppm or less. A state regulation prohibits the
construction of wells within the 100 year floodplain of Whitewood Creek, unless a variance is
granted. (WDC, 1994b).
System O&M Requirements
System O&M activities include an annual review of residential building activity within the Site
(WDC, 1994b). Findings from the review are summarized in the Monthly or Quarterly Reports.
System Activities to Date
Table 4-2 summarizes the residential building activities within the Site, reported by Homestake to
date.
Some variances have been granted for the construction of wells within the 100 year floodplain of
Whitewood Creek since the implementation of the remedy. The following table summarizes the
variances granted for well construction within the 100 year floodplain of Whitewood Creek
available from the South Dakota Water Rights Program.
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Well ViiriiiiKTs (.r;mk'il within (lie 100 Yesir I'loodphiin nl'W hik'wood (rock
Pmperlj
C "on nl\
\ iiriiiniT Ri'(|ucsl
\ iiriiincc l);iU'
Westburg
Lawrence
Construction of a domestic water supply
well on the Westberg Property along
Whitewood Creek. To protect against
contamination from tailings deposits, well
construction includes setting a protective
surface casing through the alluvium that
penetrates at least 20 feet into the bedrock.
March 7, 1989
Holsclaw
Meade
Construction of a domestic water supply
well on the Holsclaw Property along
Whitewood Creek. To protect against
contamination from tailings deposits, well
construction includes setting a protective
surface casing through the alluvium that
penetrates at least 20 feet into the bedrock.
April 18, 1990
Willson
Lawrence
Construction of a domestic well on the
Willson Property along Whitewood Creek.
To protect against contamination from
tailings deposits, well construction includes
pressure grouting the well from the top of
the aquifer to the land surface.
January 7, 1992
January 14, 1992
Wehner
Butte
Construction of a domestic well on the
Wehner Property along Whitewood Creek.
To protect against contamination from
tailings deposits, well construction includes
a surface casing grouted in through the
potentially contaminated alluvium prior to
drilling.
February 10,
1999
Problems Encountered
Based on the review of the information Quarterly Reports, there do not appear to be any
problems associated with residential building activities within the Site. For the two reported
instances of development/potential development activities within the Site, landowners were aware
of the ordinance requirements or were coordinating their respective development activities with
the County to ensure compliance with county ordinances.
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Sampling activities indicated that the Crowser Property was located on tailings impacted soil, and
the landowner agreed to complete remediation as outlined in the county development handbook,
in accordance with Site project plans. Information is not available to confirm that remedial
activities were completed at this property.
Based on a review of the available variances from the SD DENR Water Rights Program, there do
not appear to be any problems associated with the state well ban regulation. Four wells were
installed within the 100 year floodplain. Information on wells installed within the 100 year
floodplain without prior application or variances were not uncovered during this five-year review.
4.3.4 Post-Closure Residential Soil Sampling and Remediation
The remedy outlined in the ROD requires the following activities associated with Post-Closure
Residential Soil Sampling and Remediation Operations and Maintenance:
Flood Impact Soil Sampling at Remediated Residences
Five-Year Review Remedial Action Verification Soil Sampling
Residential Soil Remediation
Flood Impact Soil Sampling
Surface soil sampling will be conducted, if flooding of Whitewood Creek impacts surface soils
within the high use areas of residences that were remediated. Residents are to notify Homestake
if flood waters reach residential yards within the Site.
System O&M Requirements
The remedy outlined in the ROD requires the surface soils at remediated residences to be
re-sampled after flooding. This is to ensure that residential soil concentrations remain below the
100 ppm residential soil action level, in the event that contaminated materials may potentially be
redistributed during flooding.
If during sampling, soil concentrations are determined to statistically exceed remediation
standards, those specific areas will be remediated per the project selected remedy. Properties will
be remediated within one year of the determination that remediation is necessary (WDC, 1994b).
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System Activities to Date
During May 8-9th of 1995, a 20 to 25-year flood event occurred within the Whitewood Creek
floodplain. Flooding did not impact any remediated residences, thus, flood impact soil sampling
was not conducted (HMC, 1995c).
Problems Encountered
No problems were identified with this operation and maintenance requirement.
Five-Year Review Remedial Action Verification Soil Sampling
As part of the five-year review, site inspections and surface soil sampling will be conducted at
remediated residences to ensure arsenic concentrations remain below the soil action level of 100
PPm.
System O&M Requirements
The remedy outlined in the ROD requires an inspection and soil sampling to be conducted at
remediated residences. As part of the Five-Year Review Process, remediated properties within
and outside of the Whitewood Creek Superfund Site boundaries will be inspected to examine
property use and the condition of the remedial cover materials. In addition to the site inspection,
verification soil sampling will be conducted at properties within the Superfund Site boundary to
ensure that soil concentrations remain below the Site soil action level for arsenic of 100 ppm.
These properties may be subject to possible recontamination by wind deposition of arsenic rich
materials, importation of contaminated materials, or re-exposure of materials covered during
remediation activities.
If during verification sampling, soil concentrations are determined to statistically exceed
remediation standards, those specific areas will be remediated per the project selected remedy.
Properties will be remediated within one year of the determination that remediation is necessary
(WDC, 1994b).
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System Activities to Date
In 1996, thirteen residential properties were inspected (see Section 5.3) and six residential
properties (remediated in 1992) were sampled. One of the six properties had arsenic
concentrations that exceeded the 100 ppm soil action level. This property was remediated within
one year of its discovery (WDC, 1998), in accordance with the Site Remedial Action Plan.
Problems Encountered
No problems were identified with this operation and maintenance requirement.
Residential Soil Remediation (as necessary)
Remediation of residential soils is required for properties exceeding remediation standards that are
identified during flood impact monitoring or five-year verification sampling.
System O&M Requirements
If as a result of sampling activities, soil concentrations are determined to statistically exceed
remediation standards, those specific areas will be remediated per the project selected remedy.
Properties will be remediated within one year of the determination that remediation is necessary
(WDC, 1994b).
System Activities to Date
During verification sampling activities in 1996, one property was identified with concentrations
exceeding the remediation standard of 100 ppm. This property was remediated within one year of
its discovery (WDC, 1998), in accordance with the Site Remedial Action Plan.
Problems Encountered
No problems were identified with this operation and maintenance requirement in the Quarterly
and Monthly Reports reviewed.
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4.3.5 Disposal Site Monitoring
An annual review of the disposal site conditions is required to ensure that site conditions are
consistent with the Transportation and Disposal Plan for the Whitewood Creek Superfund Site.
System O&M Requirements
The integrity of the site fencing, vegetative cover, surface slopes, and rip-rap will be reviewed
during the annual inspection of the Disposal Site. Site conditions that are not consistent with the
Transportation and Disposal Plan will be corrected according to a timetable agreed upon by
USEPA and WDC. If the repair or correction of such conditions is not feasible, the disposal site
design will be re-evaluated (WDC, 1994b).
In the event the Disposal Site is reopened to accommodate disposal of contaminated soils
identified during sampling following flooding or as part of the five year review, Site activities will
be conducted in accordance with the Transportation and Disposal Plan (WDC, 1994b).
System Activities to Date
Table 4-3 summarizes the dates, observations and remedial actions taken during the annual
inspections of the Disposal Site.
Figure 4-5 contains photos taken during O&M activities at the disposal site during October 2000
and May 2001.
Problems Encountered
One minor problem was encountered during disposal site monitoring activities. In 1998,
unauthorized rubble (Figure 4-6) was observed outside of the disposal site. WDC coordinated
with the SD DENR and the rubble was placed in the disposal facility (HMC, 1998b).
4.3.6 Reporting
Quarterly reports of O&M activities and a five year review report assessing Site conditions are
required as a part of O&M reporting requirements for the Site.
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System O&M Requirements
WDC will submit quarterly reports to USEPA describing all O&M activities that have occurred
during the previous quarter and which are planned for the upcoming quarter. The quarterly report
will include a description of activities that have occurred at the Site including surface water
monitoring, residential soil sampling, residential remediation, disposal site inspection and
maintenance, flood impact monitoring, residential building activity within the site and the
education program. The Quarterly Reports will be prepared and submitted 30 days after each
calendar quarter.
A five-year review is required to assess Site conditions and the adequacy of remedial actions that
have been taken at the Site. The review will evaluate the protectiveness of the remedy by
examining changes in Site conditions, changes in Site risks and evaluating if the remedy has been
implemented in accordance with decision documents.
System Activities to Date
Table 4-4 summarizes all quarterly reports submitted to USEPA by Homestake to USEPA
available from the Superfund Records Center.
Homestake initiated the five year review report activities for the Site in 1997 with the Five Year
Status and Technical Review Report (Chadwick et al., 1997).
Problems Encountered
No problems pertaining to the preparation or submittal of the quarterly reports or five-year review
report were identified.
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5.0
FIVE YEAR REVIEW FINDINGS
5.1 Five-Year Review Process
5.1.1 Interview Team Members
The Whitewood Creek five-year review team was lead by Gwen Hooten and Rebecca Thomas,
the USEPA Remedial Project Managers (RPMs) for the Site. The following team members
assisted in the review:
Ted Fellman, USEPA Region VIII, Community Information Coordinator
Dale Hoff, USEPA Region VIII, Ecotoxicologist
Mark Sprenger, USEPA, Environmental Response Team (ERT)
Karen Kellen, USEPA Region VIII, Site Attorney
Mia Wood, USEPA Region VIII, Site Attorney
Mike McCeney, USEPA Region VIII, RPM
Chri s Wei s, USEPA Region VIII, Toxicologi st
Joane Lineburg, South Dakota Department of Environment and Natural Resources
Mark Lawrensen, South Dakota Department of Environment and Natural
Resources
IS SI Consulting Group, Contractor
Roy F. Weston, Contractor
Syracuse Research Corporation (SRC), Contractor
5.1.2 Community Notification
Notice of the upcoming five year review was placed in USEPA Fact Sheets during June of 1996
and 1998 (Attachment 5-1), and in Homestake's annual resident information sheet for 2000
(Attachment 5-1). Additionally, the community was notified about the review during interviews
with site residents and government officials completed by Homestake in 1996 and by USEPA in
2000 (Section 5.2).
This completed Five-Year Review Report for Whitewood Creek is available in the information
repository. Notice of its completion was placed in the local newspaper during July 2002.
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5.1.3 Five-Year Review Tasks
The Five-Year Review for Whitewood Creek consists of nine tasks:
Review of relevant documents. A review of documents for the Whitewood Creek Site
was completed for the purpose of determining the scope of the remedy, the goals fo the
remedy and its current status. The list of documents reviewed for completion of the
Five-Year Review is included as Attachment 5-2. Documents pertaining to the
Whitewood Creek Site were reviewed to determine the following:
The remedial action objectives and cleanup levels specified in the ROD and other
decision documents;
The remedial actions and their design;
Any changes to the assumptions underlying cleanup levels;
The status of the implementation of the remedy and O&M;
The status of the implementation and enforcement of institutional controls; and
The effectiveness of the remedy in meeting remedial action objectives.
Interviews. Interviews were conducted by USEPA staff, SD DENR and HMC with local
regulatory officials, response agencies, and residents to identify any problems with the
implementation and to evaluate the effectiveness of the remedy. The results of the
interviews completed for the Whitewood Creek Five Year Review are provided in Section
5.2.
Site Inspection. A Site Inspection was completed by USEPA, SD DENR and HMC to
visually confirm and document the conditions of the Site, remedy and surrounding area.
The results of the Site Inspection are reported in Section 5.3.
Risk Information Review. The Risk Information Review includes a review of the Site
ARARs and the site-specific, risk based cleanup level. An evaluation is completed to
identify if changes in ARARs, toxicity or other characteristics affect the protectiveness of
the remedy. The Risk Information Review is provided in Section 5.4.
Risk Recalculation/Assessment. A recalculation of potential site risks and an ecological
risk assessment were completed for the Whitewood Creek Site during the five-year
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review. The results are summarized in Section 5.5. The entire ecological risk assessment
is provided in Attachment 5-3.
Data Review. A review of surface water monitoring data, and five-year verification
sampling results from remediated residential properties was completed for the Whitewood
Creek Site. This information is provided in Section 5.6.
The results of these tasks are used as the basis of the assessment of the effectiveness of the
selected remedy in Section 6.0, to identify any deficiencies in Section 7.0, and to provide any
recommendations and required actions in Section 8.0 to ensure the protectiveness of the remedy
to human health and the environment.
5.2 Interviews
Interviews were conducted by USEPA, SD DENR and HMC staff with local regulatory officials,
response agencies, and residents to review the effectiveness of the remedy. The interview findings
are summarized in the following sections.
5.2.1 Interviews with Residents
All remediated properties were inspected and interviews were completed at occupied sites if
residents were available. J. Steve Peters of Homestake Mining Company, Joane Lineburg of the
SD DENR and Mike McCeney of USEPA Region VIII met with available residents on July 16
and 17, 1996. The results of these interviews were reported in Chadwick et al. (1997) and are
summarized below. The following questions were addressed for each property:
1. Have any tailings materials been imported?
2. Has Whitewood Creek flooding impacted any high-use area?
3. Have any new water wells been constructed within tailings impacted areas?
4. Has property use changed, impacting the previously delineated high-use areas?
5. Have there been any excavating activities since remediation?
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6.
Is the remedial cover intact?
7. Is any geofabric (used beneath remedial cover materials in select areas) visible?
8. Are there any special problems related to previously completed remedial activities?
Inspection and interview findings as summarized by Chadwick et al. (1997) are as follows:
Ala Property. Cover materials were observed to be in good condition. The grass cover in
the yard was not in good condition apparently from neglect. There were no apparent
changes in site use conditions. It should be noted that Alvin Ala was informally
interviewed by J. Steve Peters of Homestake Mining Company at an earlier date and his
interview was supported by inspection findings.
Balo Property. Both "upper" and "lower" properties were inspected and Kyla Balo was
interviewed. Kyla Balo reports that the modular home is being moved and there will be
only one residence at the upper property. The gravel and soil cover was observed to be in
good condition at both sites.
Berger Property. Ron and Mary Berger were interviewed. They reported that following
remediation, their root cellar tends to collect water. They believe that the imported
material restricts drainage and allows water to collect in the cellar following precipitation
events. The soil and gravel cover as well as the garden area were observed to be in good
condition. There were not apparent changes to the high use area.
Kvmala Property. Larry Kymala was interviewed. There were not apparent on-site
changes, and the gravel cover was observed to be in good condition. It should be noted
that only gravel cover was applied at this residence during remediation.
Marrs Property. The gravel and soil cover were observed to be in good condition. There
were no apparent changes at the site. It should be noted that Dan Marrs was informally
interviewed by J. Steve Peters of Homestake Mining Company at an earlier date, and his
interview was supported by inspection findings.
Tippev Property. Lyle Tippey was interviewed. He reports that there has been some
minor movement of gravel during extreme precipitation run-off events. He has reportedly
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moved displaced gravel to restore the driveway to a smooth surface. The driveway was
observed to be in good condition with no geotextile fabric evident. Also, no site changes
were observed except the original home is now unoccupied and has been replaced by a
new modular home located further from the tailings area.
Wennberg Property. Charles Wennberg was interviewed. He reports that the buffalo
grass sod placed during remediation does not "green up" as soon in the spring as native
buffalo grass. He also stated that he tries to restrict access to tailings areas located on his
property. There were no observable changes in the remedial cover or site use, except the
garden area is apparently not being used.
Will son Property. Jim Willson was interviewed. He reports that the gravel cover was
initially soft but is now solid. No changes in the remedial cover or site use conditions
were observed.
Alan Property. Gilbert Alan was interviewed. He reported that the imported soil material
was extremely "hard to work". The cover materials were observed to be in good
condition with no apparent changes in site use.
Holsclaw Property. There were no observable changes in the remedial cover or site high
use area conditions. A new pasture-to-yard road approach had been built in June 1996
outside the high use area. It should be noted that Stan Holsclaw was informally
interviewed by J. Steve Peters of Homestake Mining Company at an earlier date and his
interview was supported by inspection findings.
Nelson Property. There were no observable changes in the remedial cover or site high use
area conditions. The property is still being used as an occasional family gathering location
with no use of the garden area.
Shuck Property. Both the occupied property and the unoccupied "north" property were
inspected, and Neil Shuck was interviewed. In regard to the occupied property, he reports
that the buffalo grass sod has been extremely difficult to keep weed-free, and it "greens
up" very late in the season. He stated that he may replace it with more conventional yard
grass in the future. He pointed out that the back yard fence had been moved into a
remediated area to better protect the yard from livestock. At the occupied property, there
were no observable changes in the remedial cover or site high use area conditions, except
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the garden is no longer used. Also, there were no observable changes in the remedial
cover or site high use conditions at the Shuck north property. This property is still
unoccupied and no evidence of flooding was observed.
Westberg Property. Both residential areas at this property were inspected and Glen
Westberg was interviewed. No problems were reported. The north property is now
unoccupied and cover materials appeared in good condition. At the main residence (south
property), cover materials appeared in good condition. The driveway within the high use
areas has been paved. Also, the high use area south of the house is smaller due to
relocation of the yard fence closer to the house (away from the creek). Some slumping of
the creek bank south of the lower yard was observed, but it apparently did not impact the
high use area.
On March 21, 2000 Stan Holsclaw was interviewed by Mark Lawrensen of the SD DENR and
Ted Fellman and Gwen Hooten of USEPA Region VIII. Stan was asked the same 8 questions
given during the 1996 interviews with two additional questions:
9. What is your general impression of the project?
10. What is your impression of the risk?
Mr. Holsclaw reported that no tailings material had been imported, flooding had not impacted any
high-use area, there were no new additional wells or changes to existing wells, there were no
excavation activities within the high-use area, property use has remained the same, and the
remedial cover is intact. In general Mr. Holsclaw reported that the asphalt worked well and
washed clean. His overall impression of the risk was that the remediation did not clean up enough
of the Creek. He believes that it is safe on the asphalt but not elsewhere. The yards may be clean
but the Creek still has tailings. After nine or ten years nothing has really changed. As far as he is
concerned nothing was done to clean the Creek itself. He has further concerns that new
channelizing of the Creek threatens the loss of his barn and he cannot do anything to stop it as he
cannot change the Creek channel.
5.2.2 Interviews with Government Officials
To review the implementation and effectiveness of the county ordinance institutional controls
specified by the ROD (USEPA, 1990), interviews with government officials responsible for
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administering the controls were conducted. An interview with the government agency responsible
for managing an irrigation siphon within the Site was also conducted to review any changes in
resource use and Site conditions. On July 16, 1996, Mike McCeney of USEPA Region VIII,
Steve Peters of Homestake Mining Company and Joane Lineburg of the SDDENR met with
officials from each of the three counties (Lawrence, Butte, and Meade) responsible for
implementing the institutional controls. Mark Lawrensen of the SD DENR, and Gwen Hooten
and Ted Fellman of USEPA Region VIII met with the county officials again and with the
Manager of the Belle Fourche Irrigation District on March 21, 2000. The meetings were intended
to help USEPA determine if the institutional controls at the Site remain in place and are effective
and if there have been any changes in site conditions or resource use. The following basic
questions were asked of each government official:
1. What is your impression of the proj ect?
2. What is your impression of the risk?
3. Have there been routine communications or activities (site visits, inspections,
reporting activities, etc.) conducted by your office regarding the site? If so, please
give purpose and results.
4. Have there been any complaints, violations, or other incidents related to the site
requiring a response by your office? If so, please give details of the events and
results of the responses.
5. Do you feel well informed about the site's activities and progress?
6. Do you have any comments, suggestions, or recommendations regarding the site's
management or operation?
The parties interviewed and findings are as follows:
Belle Fourche Irrigation District Manager. Renel Hall-Beck, the manager of the Belle
Fourche Irrigation District was interviewed by Ted Fellman and Gwen Hooten of USEPA
Region VIII on March 20, 2000. The following specific questions in addition to the basic
ones were asked of the District with the following responses:
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1. Have you in the past, or will you in the future use the surface water in Whitewood
Creek? Why?
There was no use of surface water in the past and no plans for doing so in the
future. They are not set up to pull water from Whitewood Creek.
2. Have any tailings material been imported?
Not applicable
3. Have any new water wells or other irrigation structures been constructed within
tailings impacted areas? If so, describe the wells or structures.
No. All new irrigation structures are on holdfor over 5 years. The ditches do not
appear to be in the flood plain. The Bureau of Reclamation (BOR) held off on
new structures as part of Environmental Assessment (EA).
4. Has surface water usage changed, and what impact does the change have on the
impacted surface water and surrounding area?
Surface water usage has not changed.
5. Have there been any excavating, stabilizing or other activities conducted by the
irrigation district since the remediation? What was the purpose of the activity?
How effective was the activity in meeting the purpose?
Rip rap was placed in the summer of 1999for bank stabilization. It worked, but
is a temporary solution. Some material has already flown downstream. Rip rap
is designed to holdfor about a year, subject to flood events.
In response to the general questions the following responses were provided:
1. What is your impression of the proj ect?
Project is to minimize negative impacts to the environment.
2. What is your impression of the risk?
The impacts are regionalized, so the potential for risk is also. The risks are to
surface water and not groundwater. Risks are associated with mercury from
mining.
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3. Have there been routine communications or activities (site visits, inspections,
reporting activities, etc.) conducted by your office regarding the site? If so, please
give purpose and results.
Some informal activities. (BOR? District?) Placed rip rap on the Creek banks
near the irrigation siphon once since July. It was the second or third time that rip
rap was usedfor erosion control at this location. The Irrigation District has
given some tours of this site, including a group last fall (BOR, EPA). The District
is also involved in the EA process pertaining to the siphon.
4. Have there been any complaints, violations, or other incidents related to the site
requiring a response by your office? If so, please give details of the events and
results of the responses.
Not aware of any.
5. Do you feel well informed about the site's activities and progress?
Have EA and designs (for siphon). Attended BOR briefings with respect to the
siphon. Have not received as much information from EPA or the State, but new
to position (July 1999). Do not have water quality tests or sampling results from
EPA activities. Mostly concerned with any potential hazards to employees. Want
some limited information to understand current water quality concerns. Want to
be included in the information loop in terms of receiving initial reports, but not
all quarterlies, just before and after construction at siphon is sufficient.
6. Do you have any comments, suggestions, or recommendations regarding the site's
management or operation?
Answered with a question? Will EPA have environmental oversight during
construction at the siphon? EPA answers no that the Bureau of Reclamation
(BOR) will have oversight.
Lawrence County Zoning. Erik Birk, the Lawrence County Zoning Administrator was
interviewed by Mark Lawrensen of the SD DENR and Ted Fellman and Gwen Hooten of
USEPA Region VIII on March 21, 2000. The following responses were provided to the
list of six general questions.
1. What is your impression of the proj ect?
Homestake did an excellent job. They spent a lot of money, were open and honest
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with land purchases and leasing back to previous owners. Did well with the Red
Xproject which is now a gorgeous park. Homestake planted thousands of trees
and turned a terrible looking pit into a beautiful park.
2. What is your impression of the risk?
Property owners will say water has not killed them yet. The risk is low. Few
people live along the Creek and the land is used mostly for production of hay or
wheat or grazing.
3. Have there been routine communications or activities (site visits, inspections,
reporting activities, etc.) conducted by your office regarding the site? If so, please
give purpose and results.
Routine communications include permits and papers.
4. Have there been any complaints, violations, or other incidents related to the site
requiring a response by your office? If so, please give details of the events and
results of the responses.
There was one violation for building without a permit by Tommy Thompson.
5. Do you feel well informed about the site's activities and progress?
Do not feel well informed prior to 1994. It was necessary to read about activities
in the paper. After 1994, the county gained control through plats and permits.
We don't envision large developments.
6. Do you have any comments, suggestions, or recommendations regarding the site's
management or operation?
The building permittees ask us why doesn't Homestake pay for soil samples when
new people come to build? The county takes the residents' wordfor where and
how they took their soil samples.
The following specific questions in addition to the basic ones were asked of the Lawrence
County with the following responses:
1. Have any tailings materials been imported?
No tailings have been imported.
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2.
Has Whitewood Creek flooding impacted any high-use area?
There was a 50 year flood in 1997 that caused some sediment to move.
3. Have any new water wells been constructed within tailings impacted areas? If so,
what is the depth of the wells? Any changes in the existing wells?
No. Thompson built a well in the 100 ppm area, but not in the tailings area.
4. Has property use changed, impacting the previously delineated high-use areas?
Property is still residential use. There is a new bed and breakfast, but it is outside
of the high impact area.
5. Have there been any excavating activities since remediation?
Some bridge repair done by the Lawrence County Highway Department. They
placed new materials from Centennial Quarry during the work. Placed rock to
stabilize banks. There was no excavation.
6. Is the remedial cover intact?
Question not applicable.
7. Is any geofabric (used beneath remedial cover materials in select areas) visible?
Question not applicable.
8. Are there any special problems related to previously completed remedial activities?
Question not applicable.
9. What programs do you have to restrict building, well drilling and other activities in
the contaminated floodplain? How is the program executed? Give examples.
Ordinances and FEMA FIRM (Flood Insurance Rate Maps). The FEMA maps
must be adhered to. To build in the flood plain, the builder must acquire flood
insurance or engineer the facility above flood level. A licensed professional
engineer must conduct the survey.
Meade County Assessor's Office. Merlin Ehlers and Kirk Nupen, the Meade County
Commissioners were interviewed by Mark Lawrensen of the SD DENR and Ted Fellman
and Gwen Hooten of USEPA Region VIII on March 21, 2000. The following responses
were provided to the list of six general questions.
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1. What is your impression of the proj ect?
The project was well handled and addressed the problem in the least intrusive
way, by stopping exposures. Re-mining seemed dangerous since it would expose
hazards.
2. What is your impression of the risk?
Have the residents had wells tested? Assume all residents are contacted so that
they can ensure that their activities are safe.
3. Have there been routine communications or activities (site visits, inspections,
reporting activities, etc.) conducted by your office regarding the site? If so, please
give purpose and results.
There have not been routine communications. We were supplied with a map
which was incorporated into the assessment file. They try to not automatically
issue permits. This is a function of the planning board. Try to track properties
within the floodplain. No transactions have taken place in the floodplain since
the ordinance passed.
4. Have there been any complaints, violations, or other incidents related to the site
requiring a response by your office? If so, please give details of the events and
results of the responses.
No complaints, violations or other incidents are known. Some land transfers have
occurred (see paperwork showing land exchanges).
5. Do you feel well informed about the site's activities and progress?
They do not need much information and assume government and Homestake are
doing their job. Given plat built in area, need to step up efforts to identify areas
affected by ordinance. Also need to increase enforcement of building and septic
permits.
6. Do you have any comments, suggestions, or recommendations regarding the site's
management or operation?
There is a big study on the Belle Fourche being conducted, taking water samples.
Also, Homestake is trading land (in Haakon or Perkins counties?) for lands along
the Belle Fourche. Jim Wainright is contact. The Balo's are a good contact for
information as well.
5 - 12
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The following specific questions in addition to the basic ones were asked of Meade
County with the following responses:
1. Have any tailings materials been imported?
There are no known imported tailings materials. A new home (across Creek from
Holsclaw 's) is likely a single family residence. A trench was dug to install the
septic system and was not surveyed.
2. Has Whitewood Creek flooding impacted any high-use area?
Not aware of any floods impacting high-use areas.
3. Have any new water wells been constructed within tailings impacted areas? If so,
what is the depth of the wells? Any changes in the existing wells?
Should ask the State. A new residence tapped into an existing permitted well.
4. Has property use changed, impacting the previously delineated high-use areas?
Yes, the Berger residence. Don't know whether or not the property is in high use
area.
5. Have there been any excavating activities since remediation?
Only new residence.
6. Is the remedial cover intact?
Question not applicable.
7. Is any geofabric (used beneath remedial cover materials in select areas) visible?
Question not applicable.
8. Are there any special problems related to previously completed remedial activities?
Question not applicable.
9. What programs do you have to restrict building, well drilling and other activities in
the contaminated floodplain? How is the program executed? Give examples.
Subdivision ordinance and plat, building permit issuance, septic permits,
ordinance and Flood plain ordinance.
5 - 13
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Butte County Planning and Zoning Commission. Bob Morris Chairman of the Butte
County Zoning Commission and Dave Anderson, the Commissioner, were interviewed by
Mark Lawrensen of the SD DENR, and Ted Fellman and Gwen Hooten of USEPA
Region VIII on March 20, 2000. The following responses were provided to the list of six
general questions.
1. What is your impression of the proj ect?
The project was well within the scope of work and no negative comments have
been recently heard. Nobody is seeing deadfish anymore (Dave). Zoning in
place for over two years. No need to raise the issue during that time no building
requests or subdivisions near the Creek. No affect to zoning. "For all intents and
purposes, there are no permanent institutional controls as regards land within the
Site. " No controls in place. The whole county is under a Temporary Emergency
Zoning Controls (March 1, 1999) for one year to look at comprehensive land use.
Which can be renewedfor another year. Whitewood Creek falls under the
Temporary Emergency Zoning Controls. If agricultural, then the land use of
agricultural is grandfathered in as A-l. If owner of A-1 wants to sub-divide, then
land owner has to request for rezoning through the planning commission.
There has not been a need to address the lack of controls because it has not been
an issue (there have not been zoning requests on the land within the Site).
In a follow up letter to USEPA (Morris, 2000), Bob Morris clarified the
information previously given in the site interviews regarding permanent
institutional controls for land within the site. Butte County has two local
ordinances in affect that regulate building activities within the Whitewood Creek
Site. Ordinance number 94-1 addresses building in the tailings area of
Whitewood Creek Site and ordinance number 98-1 addresses building in
floodplain areas. This letter also reiterated that building within these areas has
not been an issue. The Butte County Planning and Zoning Commission has not
received any requests to subdivide or seek building permits under their temporary
zoning controls within the affected area.
2. What is your impression of the risk?
This impression depends on information available. The intent is to keep
disturbances down but if there are disturbances of the Creek, then they will affect
5 - 14
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water quality. There are no reports of health effects since remediation. Out of
sight, out of mind. The concerns have decreased over time and no one comes
forward with any problems. As long as the area remains primarily agricultural,
there will not be a problem. However, if urban sprawl pushes onto this land,
there could be a problem. The magnitude of this problem is greater than most
realize. Also, the well ban could be a question in the future (Bob). No valid
health concerns after remediation. Those informed about the Site are satisfied.
General attitude is "just get it fixed". No water quality problems (Dave).
3. Have there been routine communications or activities (site visits, inspections,
reporting activities, etc.) conducted by your office regarding the site? If so, please
give purpose and results.
Not particular to the Site.
4. Have there been any complaints, violations, or other incidents related to the site
requiring a response by your office? If so, please give details of the events and
results of the responses.
There have been no complaints for planning and zoning commission. The
affected residents are fully informed. Over time there could be problems as the
land transfers with new generations (Bob). The county commissioner hasn't
heard of any complaints, and nothing from the state (Dave).
5. Do you feel well informed about the site's activities and progress?
No. Could use bullet point information for planning and zoning to raise
awareness for people coming into the office looking to build or buy in the affected
area. No packet of information available for people. The problem is future
expansion. If someone comes in they need to know the situation with the Site.
The issue has not come up in the last two years. EPA supplied a copy of
Lawrence County's "Building Permit Handbook" for the Whitewood Creek
Tailings Area (Bob). No good reference material available. The County should
have a map of the impacted area. EPA action item. (Dave).
6. Do you have any comments, suggestions, or recommendations regarding the site's
management or operation?
Get appropriate information to appropriate people might be zoning chairman or
commissioners. If issues arise, they will need the information (Dave). The
information is good. Action is met with "if it ain't broke don't fix it" (Bob).
5 - 15
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The following specific questions in addition to the basic ones were asked of the
Commission with the following responses:
1. Have any tailings materials been imported?
Not that aware of.
2. Has Whitewood Creek flooding impacted any high-use area?
This is unknown as there is not real flooding there.
3. Have any new water wells been constructed within tailings impacted areas? If so,
what is the depth of the wells? Any changes in the existing wells?
Only the State can allow wells to be drilled.
4. Has property use changed, impacting the previously delineated high-use areas?
No.
5. Have there been any excavating activities since remediation?
No.
6. Is the remedial cover intact?
Not sure if any cleanups performed in Butte county. Private controls (i.e.
Home stake contracts should be accountedfor in review of local controls.
7. What programs do you have to restrict building, well drilling and other activities in
the contaminated floodplain? How is the program executed? Give examples.
Cannot build residential structure in Butte County in a floodplain. Wells are
covered by State authority.
5.2.3 Interviews with Remediation Contractors and O&M Contractors
Remediation O&M Contractors were interviewed to understand any problems, successes or
changes with regard to the implementation and effectiveness of the remedy. The following
questions were asked of each contractor:
1. What is your impression of the proj ect?
5 - 16
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2. What documents did you rely upon to execute the project?
3. What did you do?
4. What problems did you encounter?
5. What changes were executed?
6. Do you have any comments, suggestions, or recommendations regarding the
project (i.e., design, construction documents, constructability, management,
regulatory agencies, etc.)?
The parties interviewed and findings are as follows:
FMG. Inc. Walter Slack of FMG, Inc. was interviewed by Ted Fellman and Gwen Hooten
of USEPA Region VIII on March 21, 2000. The following responses were provided to
the list of six general questions.
1. What is your impression of the proj ect?
This was a good project for the firm. Solutions were viable given criteria and it
went well. Homestake coordinated well with owners. There were a few problem
sites where the best option would have been to buy out, but not all owners were
willing. Enjoyed working on it. Overall real good project.
2. What documents did you rely upon to execute the project?
All documents, especially consent decree, were relied on to complete project.
They followed all that EPA wanted done.
3. What did you do?
Completed observation and oversight ofplans and specifications for the remedial
sites. Plans and specifications were presented to EPA for confirmation and
changed if needed. Plans and specification were provided to Homestake for
approval. Homestake hired a contractor for the remediation. Verified that plans
and specifications were followed in accordance with EPA.
5 - 17
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4. What problems did you encounter?
There are always problems, but they worked through them.
5. What changes were executed?
Changes are part of the process and were worked out with the owner and EPA.
The changes made it fun.
6. Do you have any comments, suggestions, or recommendations regarding the
project (i.e., design, construction documents, constructability, management,
regulatory agencies, etc.)?
A lot of money was spent and could have been more wisely spent. The project was
very expensive given all the changes and modifications.
The following additional question were asked of the contractor:
1. Is there a continuous onsite O&M presence? If so, please describe staff and
activities. If there is not a continuous onsite presence, describe staff and frequency
of site inspections and activities.
No, but willing if Homestake wants.
2. Have there been any significant changes in the O&M requirements, maintenance
schedules, or sampling routines since start-up or in the last five years? If so, do
they affect the protectiveness or effectiveness of the remedy? Please describe
changes and impacts.
Question Not Applicable
3. Have there been unexpected O&M difficulties or costs at the site since start-up or
in the last five years? If so, please give details.
Question Not Applicable
4. Have there been opportunities to optimize the operation, maintenance, or sampling
efforts? Please describe changes and resultant or desired cost savings or improved
efficiency.
Question Not Applicable
5 - 18
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Ellis Engineering. Brad Ellis of Ellis Engineering was interviewed by Ted Fellman and
Gwen Hooten of USEPA Region VIII on March 21, 2000. The following responses were
provided to the list of six general questions.
1. What is your impression of the proj ect?
Went off well. There were some glitches that were included in the construction
completion report. He has not visited the site in a year. Use of the asphalt and
gravel helped in high use areas. This material minimized use and looks nice.
2. What documents did you rely upon to execute the project?
He relied on all documents but cannot remember all names. Of particular use
was the design report included in the remediation plan produced by Greg Knell of
KRW Consulting.
3. What did you do?
Construction oversight.
4. What problems did you encounter?
A garage floor cracked when raised. Topsoil was difficult to find and owner was
not fond of the soil used as it was too clayey.
5. What changes were executed?
None of the problems encountered really constituted a change. There was a
border change for the high use area, which was mutually agreed upon.
3. Do you have any comments, suggestions, or recommendations regarding the
project (i.e., design, construction documents, constructability, management,
regulatory agencies, etc.)
He did not have any particular recommendations but suggests that the project
was perhaps overkill and was very expensive. They followed good construction
practices, kept clean and removed soil to on-site repository.
The following additional question were asked of the contractor:
1. Is there a continuous onsite O&M presence? If so, please describe staff and
activities. If there is not a continuous onsite presence, describe staff and frequency
5 - 19
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of site inspections and activities.
There is not a continuous onsite presence. The activities are complete.
2. Have there been any significant changes in the O&M requirements, maintenance
schedules, or sampling routines since start-up or in the last five years? If so, do
they affect the protectiveness or effectiveness of the remedy? Please describe
changes and impacts.
Question not applicable.
3. Have there been unexpected O&M difficulties or costs at the site since start-up or
in the last five years? If so, please give details.
Question not applicable.
4. Have there been opportunities to optimize the operation, maintenance, or sampling
efforts? Please describe changes and resultant or desired cost savings or improved
efficiency. What could be done better?
Optimized as much as possible within requirements.
5.2.4 Interviews with Homestake Mining Corporation
A1 Cox of Homestake Mining Company was interviewed to understand any problems, successes
or changes in implementing the remedy in order to access its effectiveness. The interview was
conducted on May 15, 2001 by Gwen Hooten of USEPA. The questions asked and responses
given are summarized below:
1. What is your impression of the proj ect?
Based on Homestake Mining Corporation's work, there doesn't seem to be a
problem. Nothing was identified to indicate the remedial action is not protective.
2. What is your impression of the risk?
The remedial action remains protective.
3. Have there been routine communications or activities (site visits, inspections,
reporting activities, etc.) conducted by your office regarding the site? If so, please
give purpose and results.
5-20
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Quarterly O&M reporting, periodic inspections (of soil disposal site annually),
annual public information fact sheet for site residents. Don't necessarily visit
quarterly.
4. Have there been any complaints, violations, or other incidents related to the site
requiring a response by your office? If so, please give details of the events and
results of the responses.
There was an issue with the root cellar at the Berger property (remediated in
1992) a year or two ago. The property had humidity problems in their root
cellar. Remediation solved the problem.
5. Do you feel well informed about the site's activities and progress?
Mostly yes, especially on significant issues. An office in Spearfish and
Whitewood would allow us to be in contact with the local feel of the project.
6. Do you have any comments, suggestions, or recommendations regarding the site's
management or operation?
No specific recommendations. No more 5-Year reviews would be nice, as this
review has evolved beyond a regular five year review.
7. Have you in the past, or will you in the future use the surface water in Whitewood
Creek? Why?
Not familiar with water rights on Whitewood Creek. Homestake does not have
specific items/activities involving creek flows.
8. Have any tailings materials been imported? Have any tailings been removed from
the Creek?
We are only aware of a small amount of tailings that were removedfrom the
Creek and placed in the soil disposal area. We need to check to see how
vegetative cover is doing.
9. Have any new water wells or other irrigation structures been constructed within
tailings impacted areas? If so, describe the wells or structures.
We are not aware of any new structures or water wells. The shallow well ban is
well known by residents. They are notified of the ban in the annual educational
fact sheet. There are no regular site visits to check for new wells.
5-21
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10. Has surface water usage changed, and what impact does the change have on the
impacted surface water and surrounding area?
Not aware of any significant changes.
11. Has Whitewood Creek flooding impacted any high-use areas?
Don't believe so, at least not since remediation.
12. Has property use changed, impacting the previously delineated high-use areas?
There have been land purchases and rental to former owners in the Site.
Homestake owns some property on the Belle Fourche, but not recently acquired.
Talk with Harold Barn.
13. Have there been any excavation activities since remediaton?
There has been rip rap and stabilization work by the siphon.
14. Is the remedial cover intact?
Yes. Additional work at Holsclaw property resolved an issue with remedial cover.
15. Is any geofabric (used beneath remedial cover materials in select areas) visible?
Not aware of but contact Greg Canel at FRK.
16. Are there any special problems related to previously completed remedial activities?
Just at the Berger and Holsclaw properties.
17. What programs do you have to restrict building, well drilling and other activities in
the contaminated floodplain? How is the program executed? Give examples.
We rely on the local ordinance program to restrict activities.
18. Can you discuss Homestake's land agreements along Whitewood Creek? How
does this relate to efforts to maintain institutional controls?
See question 12.
19. Were each of these properties filed?
See question 12.
5-22
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20. Do you have 1995 soil sampling results from Ray and Becky Crowser's property
(associated with building permit 3788)? Crowser states that Homestake already
took samples, and they are outside 100 mg/kg limit for arsenic.
Will check.
21. What documents did you rely upon to execute the project? What did you do?
What problems did you encounter? What changes were executed?
The Sampling and Analysis Plan outlined the criteria to determine which sites
would be remediated. We sampled along the Creek to determine Arsenic
concentrations. Homestake provided this information in a database submitted to
EPA. The ROD is the driver.
22. Do you have any comments, suggestions, or recommendations regarding the
project (i.e., design, construction documents, constructability, management,
regulatory agencies, etc.)
No. Lot of effort in Construction Completion Report. Consent Decree has
created some problems, like what are the obligations or responsibilities of
Homestake? Need some clarity.
23. Is there a continuous onsite O&M presence? If so, please describe staff and
activities. If there is not a continuous onsite presence, describe staff and frequency
of site inspections and activities.
Continuous activities include: continue quarterly reporting, fact sheet mail outs,
surveillance at the disposal site and water quality monitoring.
24. Have there been any significant changes in the O&M requirements, maintenance
schedules, or sampling routines since start-up or in the last five years? If so, do
they affect the protectiveness or effectiveness of the remedy? Please describe
changes and impacts.
No, not that I am aware of. We tried to maintain consistency.
25. Have there been unexpected O&M difficulties or costs at the site since start-up or
in the last five years? If so, please give details.
No big ticket items, just money spent on developing the Five-Year Review. Water
quality monitoring has become more expensive.
5-23
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26. Have there been opportunities to optimize the operation, maintenance, or sampling
efforts? Please describe changes and resultant or desired cost savings or improved
efficiency.
Have not identified any significant changes regarding cost.
5.2.5 Summary of Interview Results
No significant changes in Site conditions were reported during the 1996 or 2000 interviews,
except for building activities occurring at some residential properties. Tailings materials were not
reported to be imported into the Site, no known excavation activities impacting tailings deposit
areas were reported, and flooding is not known to have impacted any residential areas of the Site.
The Belle Fourche Irrigation District reported conducting bank stabilization activities on several
occasions to prevent erosion of the bank near the irrigation siphon. Homestake reported
purchasing land and renting it back to the former owners within the Site boundaries.
Development was reported at several residential properties in both Lawrence and Meade Counties
since remediation. Some of these development activities occurred within and outside of the 100
ppm arsenic tailings impacted areas. Butte County did not report any requests for development
within the tailings impacted areas since the implementation of its county ordinance.
Successes and Problems in the Implementation of Institutional and Access Controls
The site interviews revealed several instances of development at residential properties within the
Whitewood Creek Site, some of which occurred in the 100 ppm arsenic tailings impacted area.
The available information on the residential construction activities are summarized below:
Siimniiin of l)c\clopmciil Acli\ ilics w illiin (lie \\ hik'wnod ( ivck Supcrl'iiml Silo
Pmperlj
l)c\clopim-nl
Ac(i\ i(\
l.ociilcd in 100 ppm
Arsenic liiilin^s
1 inp;icle«l Ami?
Soil Siiinplinii
(onduck'd ;ind Results
Johnson
Bed and Breakfast
No
No, sampling not
required for areas outside
100 ppm Tailings
Impacted Area.
5-24
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Sum in sin ol' Doclopmcnl Acli\ ilios w illiin llic \\ hilcwood Civck Supi-i'l'mid Silo
Proper(\
DoclopillCIII
Acli\i(\
I.ocsilcd in 100 ppm
Arsenic l;iilin^s
Impsiclcd Aivsi?
Soil Ssimplinvi
( ondiiclod sind Results
Crowser
Placed mobile home
on property.
Yes
(in an area"barely above
100 ppm arsenic")
Owner agreed to conduct
sampling, however
information not available
from interview on results.
Thompson
Placed mobile home
on property and
built a well.
Yes
Information not
available.
Berger
Built new residence
and installed piping
to tap into a
neighbor's existing
well.
Information not
available.
Information not
available.
Unknown Property
("across the Creek
from the Holsclaw
residence")
Built new home and
installed a septic
system.
Information not
available.
Information not
available.
As shown in the table, there were two instances of development (Crowser and Thompson
properties) within the tailings impacted areas without the prior required application or sampling
specified by the county ordinances. Information on some of the other reported development
activities were not available to determine if the county ordinance development guidelines were
followed.
From the available information gathered during the site interviews, it seems that the county
ordinance development guidelines for residential building within the Whitewood Creek Site are
not consistently followed or reported. Thus, this institutional control may not be functioning
effectively to limit residential exposures to arsenic impacted soils.
Successes and Problems with System Operations and Maintenance (O&M)
Homestake Mining Company did not report any unexpected difficulties with Operations and
Maintenance (O&M) activities or costs at the Whitewood Creek Site since startup. No other
problems were reported during the site interviews.
5-25
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Unusual Situations or Problems
No unusual situations or problems are reported during the site interviews.
5.3 Site Inspection
A Whitewood Creek Site Inspection was completed by USEPA to visually confirm and document
the conditions of the Site, remedy and surrounding area.
5.3.1 Date and Conduct of Site Inspection
J. Steve Peters of Homestake, Joane Lineburg of SD DENR and Mike McCeney of USEPA
Region VIII inspected all remediated residential properties on July 16 and 17th, 1996.
5.3.2 Activities
Residential properties that were remediated during the remedy were inspected. The properties
were examined for any degradation in or changes to remedial cover and for changes in land use
that may have occurred since remediation. The findings from the property inspections are
summarized below:
Sum in sin ol' Kcsidcnlisil Site Inspection lindin^s
Residence
Ohscncd ('hsingcs in
l.sind I sc
Keniedisil ( o\cr
ALA
No apparent changes in site use.
Observed to be in good condition.
BALO
(upper and lower)
Modular home being moved, so that
only one residence at upper property.
Observed to be in good condition.
BERGER
No apparent changes in high use area.
Appears to be in good condition.
KYMALA
No apparent onsite changes.
Cover observed to be in good condition.
MARRS
No apparent changes at the site.
Gravel and soil appeared in good condition.
TIPPEY
Original home now unoccupied. New
modular home located further from tailings
area.
Driveway observed to be in good condition, no
geotextile fabric evident; minor movement of
gravel during extreme precipitation.
WENNBERG
No observed changes in site sue. Garden
area apparently not in use.
No observable changes in remedial cover.
5-26
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Sum in sin ol' Kcsidcnlisil Site Inspection lindin^s
Residence
Ohscncd (h singes in
l.sind I se
Kemedisil ( o\cr
WILLSON
No changes in site use.
No changes in remedial cover.
ALAN
No apparent changes in site use.
Cover materials observed in good condition.
HOLSCLAW
No observed changes in site high use area
conditions. Built pasture to yard road
approach in 1996.
No observed changes in cover.
NELSON
No observable changes in high use
conditions. Garden area not in use.
No observed changes in cover.
SHUCK
Unoccupied
(north)
No observed changes in high use conditions
or flooding.
No observed changes in remedial cover.
Occupied
No observed changes in high use conditions.
Garden is no longer used.
No observed changes in remedial cover.
WESTBERG
North
Property now occupied.
Cover materials appeared in good condition.
South
(main
residence)
Driveway within high use area was paved.
Yard fence moved closer to house making
high use area south of home smaller. Some
slumping of creek bank south of lower yard.
Cover materials observed in good condition
Source: Chadwick et al., 1997.
5.3.3 Summary of Site Conditions
No significant degradation of remedial cover or any significant changes in land use at remediated
properties were discovered as part of the five-year review residential site inspection activities
(Chadwick et al., 1997). The remedial cover at residences remains intact.
5.4 Risk Information Review
5.4.1 ARARs Reviewed
Remedial actions under CERCLA are required by the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP) and EPA guidance and policy to comply with applicable or
relevant and appropriate standards, requirements, criteria, or limitations during and at the
completion of the action. These Applicable or Relevant and Appropriate Requirements (ARARs)
include both state and federal environmental laws and state facility siting laws. These
requirements are threshold standards that any selected remedy must meet, unless an ARAR waiver
is invoked.
5-27
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ARARs are either contaminant, location, or action specific. Contaminant specific ARARs
establish acceptable amounts or concentrations of chemicals which may be found in or discharged
to the ambient environment. Location specific ARARs relate to the geographical or physical
positions of sites, and place restrictions on the conduct of cleanup activities or concentrations of
hazardous substances. Action specific ARARs are usually technology based or activity based
requirements or limitations on actions taken with respect to hazardous substances, pollutants or
contaminants.
As part of the five-year review, the ARAR requirements identified in the ROD for the remedy are
examined to assess, as part of the remedy, whether they are still protective of human health and
the environment. ARARs are examined for new or revised requirements (such as drinking water
Maximum Contaminant Levels (MCLs)) that have occurred since the signature of the ROD. Only
those ARARs that address risks posed to human health or the environment are reviewed (USEPA,
1999).
Table 5-1 lists the ARARs for the Whitewood Creek Superfund Site specified by the ROD
(USEPA, 1990) and by the 1991 Explanation of Significant Differences (ESD). According to the
ROD for this Site, a waiver was invoked for complying with maximum contaminant levels for
arsenic under the Safe Drinking Water Act and the arsenic ambient water quality criteria for the
protection of human health by consumption of fish because of the technical impracticability of
meeting these requirements (USEPA, 1990).
The following ARARs were reviewed for changes that could affect the protectiveness of the
remedy to human health and/or the environment:
Safe Drinking Water Act, National Primary Drinking Water Standards (40 CFR
Part 141)
Clean Water Act, National Ambient Water Quality Criteria (40 CFR Part 131)
Resource Conservation and Recovery Act (40 CFR Parts 241, 257 and 264)
Clean Air Act, National Ambient Air Quality Standards (40 CFR Part 50)
South Dakota Drinking Water Standards (ARSD 74:04:05)
5-28
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South Dakota Groundwater Quality Standards, Maximum Contaminant Levels
(ARSD 74:54:01)
South Dakota Surface Water Quality Standards (ARSD 74:51:01)
South Dakota Water Right Rules (ARSD 74:02)
South Dakota Solid Waste Disposal Act (ARSD 74:27)
South Dakota Clean Air Act, Ambient Air Quality Standards (ARSD 74:36:02)
Chemical Specific ARARs
ARARs for the contaminants of concern identified in the 1990 ROD (USEPA, 1990) and the
1997 Screening Level Ecological Risk Assessment for Whitewood Creek (ISSI, 1998) were
reviewed for changes that may affect the protectiveness of the remedy to human health and the
environment. Table 5-2 summarizes the changes in the chemical-specific ARARs by comparing
the current regulations with the regulations in effect at the signing of the ROD in 1990. These
standards are relevant to Site groundwater as a potential future drinking water source, the surface
waters of Whitewood Creek for the protection of human health from fish consumption and for the
protection of aquatic life and ambient air. Some federal and state regulations for various
chemicals have been revised since the signing of the ROD in 1990 to be either more or less
stringent. The result of these changes is to increase (a less stringent regulation) or decrease (a
more stringent regulation) the allowed concentrations of chemicals in groundwater, surface water
or air. Table 5-3 summarizes the changes in stringency for chemicals in groundwater, surface
water and ambient air that have occurred since the ROD.
Table 5-2 presents both the total recoverable and dissolved ambient water quality criteria for the
protection of aquatic life. However, the federal and state surface water quality criteria in effect at
the time the ROD were based on total recoverable metals. Since the signing of the ROD, the
federal and state regulations have changed to add criteria specific to dissolved metals
concentrations. Thus, the total recoverable and dissolved concentrations of metals provided in
Table 5-2 are for comparison purposes only.
According to the ROD, a waiver was invoked for complying with maximum contaminant levels
(MCLs) for arsenic in groundwater under the Safe Drinking Water Act and the water quality
5-29
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criteria for the protection of human health by consumption of fish because of the technical
impracticability of meeting these requirements (USEPA, 1990). Thus, the changes in the federal
and state arsenic surface water quality criteria, drinking water standards, and state groundwater
quality standards do not affect the protectiveness of the remedy because, under the waiver, these
standards are not required to be attained.
Site-specific water quality criteria for 10 metals are specified for the upper reach of Whitewood
Creek, from Interstate 90 to its confluence with Gold Run Creek. With the exception of copper,
all ambient water quality criteria for the metals of concern have changed since the 1990 ROD as
summarized in the following table:
Sik--S|K-iil'k- \\ iili-r Qu:ilil\ ('riu-ri;i fur \\ hili-wmid Civi-k
I'iiim Inu-rsiiiu- 'JO in ('iinl'liii'iii'i' \\ illi Giilri Run Civi-k
('Ih-iii k;il
30-il;i\ (ll»/l.)
1990 S|;iihI;i|-(Is |;i|
2001 Sl;ill«l;iI'lls |l>|
Cyanide
209.3
80*
Copper
80
80
Cadmium
4.2
10
Silver
3.9
20
Arsenic
67.4
NA
Chromium
4
NA
Mercury
0.24
0.8
Zinc
45.8
NA
Lead
32.4
70
Nickel
37.3
NA
Standards are expressed as total concentrations, unless otherwise noted.
*weak acid dissociable (WAD) Cyanide
NA - Not applicable, no stream specific criteria for this chemical.
Sources:
[a] Administrative Record of South Dakota (ARSD) 74:03:02:48, 1990
[b] Administrative Record of South Dakota (ARSD) 74:51:01:56, 2001
The changes in criteria for total recoverable cadmium, silver, mercury and lead increase the
allowable concentrations of these substances in the surface water of the upper reach of
Whitewood Creek. The chemicals arsenic, chromium, zinc, and nickel no longer have
stream-specific numeric criteria. Thus the water quality criteria for these metals are the same as
the South Dakota water quality standards.
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Since the signing of the ROD in 1990, the state designated beneficial uses for the lower reach of
Whitewood Creek, from 1-90 to the Belle Fourche River, have been upgraded from warm water
semi-permanent fish life propagation waters to warm water permanent fish life propagation
waters. The change in beneficial use status results in a change in the suspended solids water
criteria (adding a daily maximum criteria of 158 mg/L) lowers the maximum allowable
temperature from 90°F to 80°F.
One change in ambient air quality standards occurred since the ROD. The state ambient air
quality standard lowered the maximum allowable concentration of particulates with a diameter of
10 micrometers or less (PM10) from from 60 ug/m3 to 50 ug/m3 over 24 hours. This change does
not affect the protectiveness of the remedy. The standards are applicable to the Site, especially
during remediation, so that fugitive dust from construction does not cause the area to exceed
ambient standards.
Action-Specific ARARs
Table 5-4 summarizes the changes to action-specific ARARs that have occurred since the ROD.
The majority of these changes modify design requirements for disposal facilities. Two of these
regulations (40 CFR 264.301 and 40 CFR 264.251) require that waste pile and landfill units that
are new, lateral expansions of existing units or units that are being reused after July 29, 1992 to
have two or more liners and leachate collection, removal and detection systems. These changes
are currently not applicable to the disposal unit at the Whitewood Creek Site. Currently, the
disposal unit is inactive and is not undergoing new construction/expansion or replacement
(triggers for the new design requirements). However, these regulations may be applicable in the
future if the use of the disposal facility resumes, and/or the unit undergoes new construction or
expansion to accommodate acceptance of additional wastes from any residential remedial
activities. These changes currently do not affect the protectiveness of the remedy. Future activity
at the disposal facility may trigger the applicability of these changes to the regulations and would
affect the protectiveness of the remedy.
One modification to a state solid waste regulation may be applicable to the Site and its
protectiveness. A state design regulation was modified to require discharges of retained surface
waters from the facility to meet the storm water discharge requirements of 40 CFR 122. This
modification may be applicable to the disposal facility if it is not exempted as either a mining
waste or inactive mining facility from the regulation.
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Both a federal and a state regulation, 40 CFR 241.200-211 and ARSD 74:27:03:08, have been
repealed since the ROD and ESD were signed in 1990 and 1991. Repealing these regulations
does not make the remedy more or less protective. The regulations were removed because they
were "obsolete" and addressed by other regulations.
5.4.2 Review of Site-Specific Cleanup Level
In addition to federal and state regulations, a site-specific risk-based cleanup level for arsenic was
established for residential soils. This action level assumed that remedial action efforts aimed at
groundwater, the tailings area and the irrigated cropland area were in place, and thus only
addressed exposure to residential soils (Jacobs, 1989). A soil action level of 100 mg/kg arsenic
for residential soils was derived in the Endangerment Assessment (Jacobs, 1989) based on a
1E-04 target cancer risk protectiveness level selected by USEPA. This soil action level was also
determined to reduce non-cancer risks to an acceptable level (USEPA, 1990).
The soil action level for arsenic was reviewed as part of this five-year review process. Although
there have been some changes in the toxicity factors and exposure parameters recommended by
USEPA for evaluating cancer and noncancer risks from arsenic (SRC, 2001a), USEPA still
considers the soil action level of 100 mg/kg to be adequately protective of human health.
5.5 Risk Recalculation and Assessment
This section presents the results of any assessment and/or re-calculation of human health and
environmental risks at the Site conducted as part of this five-year review.
5.5.1 Human Health Risk Assessment
Residential Soil Action Level
As discussed in Section 5.4.2, the residential soil action level for arsenic was reviewed (SRC,
2001a) and is considered by USEPA to still be adequately protective of human health.
Acute Arsenic Exposure
In a memo to Homestake (USEPA, 1997a), USEPA Region VIII identified the potential need to
evaluate possible acute human health risks from acute arsenic exposure. As discussed in SRC
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(2001a), there is still substantial uncertainty associated with short-term arsenic exposure. Until
sufficient methods and data become available to permit the quantification of these risks, USEPA
considers the current soil action level to be sufficient to reduce or minimize risks from acute
arsenic exposure.
Arsenic Exposure From Fish Consumption
Potential risks to recreational fisherman consuming fish from Whitewood Creek were evaluated
(SRC, 2002) as part of the five-year review. Based on the review, cancer and non-cancer risks
from arsenic in fish tissue are below a risk level identified by USEPA (1991) as typically requiring
action at Superfund Sites. Thus, the current remedy is judged by USEPA to remain protective of
human health.
5.5.2 Ecological Risk Assessment
At the outset of the Five Year Review, EPA sought to evaluate the adequacy of the ROD not only
for the protection of human health, but also the protection of ecological receptors and the
environment. After a review of available documents that provide information on potential
ecological risks at the site (Fox Consultants, Inc., 1984a and 1984b, Environ Group, 1985; ICF,
1989c, Jacobs Engineering, 1989, USEPA 1989a), EPA determined that the existing evaluations
were not adequate to reliably assess whether existing site conditions do or do not pose
unacceptable risks to ecological receptors. For this reason, EPA performed an ecological risk
assessment for the site, using the most relevant and appropriate ecological risk assessment
guidance (USEPA, 1989b, 1992, and 1997b).
Screening Level Assessment
In accordance with EPA guidance, the ecological risk assessment process began by performing a
screening level ecological risk assessment (SERA) (ISSI, 1998). The primary sources of
contamination that were evaluated in the SERA were the tailings that exist along the banks of
Whitewood Creek, as well as chemicals that exist in the water and sediment of the Creek. The
main chemicals of potential concern at mining sites are inorganics, including metals in the ore that
is mined and processed, as well as chemicals that are used to extract metals from the ore. This
included arsenic, cadmium, chromium, copper, cyanide, lead, mercury, nickel, selenium, and zinc.
Ecological receptors evaluated in the SERA included aquatic species (fish and benthic
macroinvertebrates) residing in Whitewood Creek, and terrestrial receptors (plants, soil
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invertebrates, birds, wildlife) that reside in the riparian zone adjacent to Whitewood Creek.
Exposure pathways that were quantitatively evaluated in the SERA included:
Direct contact of aquatic receptors (fish, BMI, periphyton) with surface water
Direct contact of BMI with sediment
Direct contact of terrestrial plants with soil
Direct contact of soil invertebrates with soil
Ingestion of surface water, sediment, soil by avian and mammalian wildlife
Ingestion of food items (fish, BMI, terrestrial plants, soil invertebrates) by avian and
mammalian wildlife
A summary of the screening level risk findings presented in the SERA is provided in Table 5-5.
Based on the preliminary risk characterization in the SERA, none of the exposure pathways
considered in the SERA could be excluded, and further evaluation was recommended for all
exposure pathways.
Collection of Data to Fill Key Data Gaps
The SERA identified a number of data areas where additional information was needed to help
improve the reliability and accuracy of the risk assessment. A summary of these data gaps and
recommendations for data collection activities is provided in Table 5-6. These data gaps were
used to help development of a field sampling Quality Assurance Work Plan (QAWP) (ERT,
1999a) and Data Quality Objectives (DQOs) (ERT, 1999b). Extensive new data were collected
under this QAWP in 1998 and 1999, and these data were then used to help support the baseline
ecological risk assessment.
Baseline Risk Assessment
EPA issued a draft baseline ecological risk assessment (BERA) in August 2001 (SRC 2001b).
EPA received written comments on the draft BERA from HMC and SD DENR. Based on these
comments, EPA revised and finalized the ERA. The findings of the final ERA are summarized
below.
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Stream Viability and Function
Risks to aquatic receptors from most COPCs in surface water are generally below a level
of concern, although some low level and intermittent stress may occur. Cyanide is not
likely to be of concern to stockable size fish, but available data are not sufficient to
determine if sensitive life stages of fish or BMI may be at risk from cyanide.
Risks to aquatic receptors from COPCs in sediment and pore water do not appear to be
above a level of concern at most stations, although risks from arsenic and cadmium might
be of concern in some locations.
Seep water is a source of increased COPC concentrations in Whitewood Creek.
However, the seep water has little apparent toxicity, and any exposures of aquatic
receptors to seep water are minimized by dilution of the seep water is in the creek.
Exposures of aquatic receptors by ingestion of aquatic prey items and/or sediment do not
appear to be of concern.
Population surveys of fish and benthic invertebrates indicate the communities are generally
abundant and diverse, although the possibility of an impact cannot be excluded from these
data.
Based on these findings, EPA concluded that COPCs in the aquatic ecosystem may result in some
stress to aquatic receptors, but that the level and severity of any effects are probably not
substantial.
Riparian Floodplain Function and Viability
Site soils are not generally toxic to plants or soil invertebrates
If plant roots are exposed to seep water, phytotoxicity from root exposure to arsenic
could be occurring, but confidence in this conclusion is low.
Terrestrial plant and microinvertebrate population data are insufficient to support a
quantitative conclusion
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Based on these findings, EPA concluded that the viability and function of the riparian floodplain is
probably not substantially impacted by mining-related releases.
Viability of Terrestrial Wildlife
Risks to wildlife do not appear to be of significant concern for exposures that occur from
ingestion of surface water, seep water, or food items.
Many terrestrial receptors are predicted to have elevated risk of adverse effects from
ingestion of arsenic in soil or sediment.
Site data confirm that small mammals have increased exposure to arsenic, but there are no
independent data from site-specific toxicity testing or quantitative population surveys that
can confirm or refute the predicted risk from arsenic.
Based on this, EPA concluded that arsenic in soil or sediment may pose a risk to some wildlife
receptors, but that this conclusion should be considered tentative unless additional lines of
evidence can be added to the evaluation.
Viability of the Amphibian Community
Some species of amphibians (but not all) may be at risk from dissolved COPCs in surface
water.
Risks from sediment or diet cannot be evaluated quantitatively, but are expected to be
minor.
Based on this, EPA concluded that risks to some amphibians are possible, but that this conclusion
should be considered tentative unless additional lines of evidence can be added to the evaluation.
Summary
Substantial data are available to evaluate the potential risks to aquatic and terrestrial ecological
receptors at the Whitewood Creek site. Based on an evaluation of the weight of evidence across
all available lines of evidence, EPA has concluded that mining-related chemicals probably are
causing some effects on both the aquatic and the terrestrial ecosystems, but that these effects are
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low level and are generally not sufficient to result in substantial disruption of ecosystem function
or viability. Based on this, the current remedy is considered to be adequate for protection of
ecological receptors and the environment.
5.6 Data Review
5.6.1 Residential Verification Sampling
The Operation and Maintenance Plan for the Site (WDC, 1994b), requires verification soil
sampling at remediated residences within the Site boundaries as part of the five-year review
process. These properties may be subject to possible recontamination by wind deposition of
arsenic rich materials, importation of contaminated materials, or re-exposure of materials covered
during remediated activities. Verification sampling at these properties ensures that the remedy is
protective of human health by confirming that arsenic concentrations are below the 100 mg/kg
action level for residential soils. If during verification sampling activities, arsenic concentrations
are discovered that statistically exceed the 100 mg/kg soil action level, those specific areas will be
remediated per the project selected remedy within one year of the determination that remediation
is necessary.
Soil sampling was conducted at 6 residential properties within the Site boundaries on July 18 and
19, 1996. Samples were collected and analyzed per Addendum E of the O&M Plan (WDC,
1994b), with one exception. Soil samples were collected from a depth interval of 0 to 1 inch,
rather than the depth interval of 0 to one-half the remedial fill material (as specified in the O&M
Plan). This modification to the sampling plan was implemented per correspondence from Michael
McCeney of USEPA dated July 17, 1996 (Chadwick et al. et al., 1997).
Table 5-7 summarizes the results for the five year review residential verification sampling
program.
Arsenic concentrations above the site action level of 100 mg/kg were detected at one of the six
residences sampled, in two driveway samples collected at the Holsclaw property (Chadwick et al.,
1997). The average arsenic concentrations measured at the properties during verification
sampling are summarized below:
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PnilK-m
NiiihIkt ill' S;iiii|)k's
I'Wi AI'si nii
(iiiHvnlmliiins
Alan
5
34
Nelson
5
13
Shuck
4
28
Shuck North
3
16
Westberg
2
12
Holsclaw
33
87
Source: Chadwick et al., 1997
Additional intensive soil sampling was conducted at the Holsclaw property in accordance with
Section 4.5.3 of the Whitewood Creek Superfund Site Sampling and Analysis Plan for Residential
Remediation and Surface Water Monitoring SAP (WDC, 1991). Sampling activities indicated
that the property high use area had been impacted by arsenic containing materials. The driveway
area was speculated to have been impacted by deposition of tailings from vehicle tires. Higher
arsenic concentrations were detected in the driveway area and apparent tailings materials were
observed in samples collected from the north side of the driveway. A garden area with arsenic
concentrations greater than 100 mg/kg appeared to contain imported materials, probably derived
from a tailings impacted area (Chadwick et al., 1997).
As required by the O&M Plan (WDC, 1994b), remedial activities were conducted at the Holsclaw
property. The remedial action at this individual property began in the November 1997 and was
completed late June 1998. A post-construction inspection of the residence on July 13, 1998 did
not identify any items of significant concern. The construction completion report was submitted
in August of 1998 (WDC, 1998).
Verification sampling was also conducted in October 2001 (HMC, 2001a). However, the results
from this sampling event were not available for inclusion in the current five-year review report.
The next five-year review of the Site will present the results from the October 2001 sampling
event.
5.6.2 Surface Water Quality
The Site remedy requires long term monitoring of surface water quality to evaluate the effects of
uncertain rates of release of arsenic into the surface waters of Whitewood Creek. Therefore, as
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part of the five-year review, these data were reviewed to determine if any significant time trends
were apparent and to determine if surface water concenteration values are protective of human
health and aquatic life (USEPA, 1990).
Surface Water Data
Surface water data were collected from two USGS sampling stations on Whitewood Creek within
the Superfund site boundaries. The upper USGS Station (06436180) is located along Whitewood
Creek near the Crook City bridge, about 1.1 miles south of the city of Whitewood, South Dakota.
The lower Whitewood Creek USGS Station (06436198) is located about 3.2 miles above the
confluence with the Belle Fourche River, about 3.7 miles west of Vale, South Dakota (Figure 5-
1). Surface water quality data for arsenic, antimony, cadmium, copper, cyanide, lead, mercury,
nickel, selenium and zinc collected during the period of January 1990 through September 1999
(available electronically from USGS) were reviewed.
Time Trends
Surface water data were plotted for each USGS sampling station by sampling date to examine
trends in concentrations (dissolved and total recoverable) over time. For each case (dissolved or
total at a station), the best fit linear regression line was determined. The results are provided in
Figure 5-2, and summary statistics for the regression are presented in Table 5-8. No cases were
observed of a statistically significant increase in concentration over time. In 23 out of 36 cases,
the slope of the line was not significantly different from zero, indicating no apparent trend of
increasing or decreasing concentrations. In 13 out of 36 cases, a small (0.1 to 1 ug/L per year)
but statistically significant negative trend was observed, indicating a slow trend toward lower
concentrations of these chemicals over time.
Protectiveness of Human Health
Figure 5-3 compares surface water concentrations at both the upper and lower USGS sampling
stations during this period to the federal ambient water quality criteria (AWQC) for human health
from fish consumption.
Arsenic was the only chemical to exceed federal AWQC for the protection of human health from
the consumption of fish. This criteria was exceeded at both the upstream and downstream
sampling locations within the Site. However, this AWQC does not take into account the finding
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that much of arsenic in fish is non-toxic, and this ARAR has been waived at this Site. In order to
evaluate the potential risks to humans from arsenic in fish, an evaluation based on measured
concentrations of arsenic in fish tissue was performed (SRC, 2002). As mentioned above (see
Section 5.5.1), the potential risks from arsenic to recreational fishermen consuming fish from
Whitewood Creek are below the level identified by USEPA (1991) as typically requiring action at
Superfund sites. Thus, the current remedy is judged to remain protective of human health.
Protectiveness of Aquatic Life
A detailed evaluation of potential risks to aquatic receptors from chemicals in surface water was
conducted as part of the ecological risk assessment conducted at the Site (Attachment 5-3,
Section 6.2.1) to evaluate the protectiveness of the remedy to the environment. This evaluation
included the selection of COPCs for surface water and a comparison of COPC concentrations to
the federal AWQC for COPCs in surface water (Attachment 5-3, Figure 6-1) both within and
outside of the NPL site boundaries. Some copper, lead, and selenium concentrations in surface
water within the NPL site exceeded the chronic AWQC, suggesting some low level and
intermittent stress may occur from these chemicals. The ERA concluded that although mining-
related chemicals probably are causing some effects on both the aquatic ecosystems, these effects
are low level and are generally not sufficient to result in substantial disruption of ecosystem
function or viability. The current remedy is considered to be adequate for protection of ecological
receptors and the environment.
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6.0 ASSESSMENT
This section summarizes the conclusions of this five-year review report, based on the information
presented in previous sections. In assessing the protectiveness of the remedy, the following
questions are examined:
Have conditions external to the remedy changed since the selection of the remedy?
Has the remedy been implemented in accordance with decision documents?
Has any risk information changed since the remedy was selected?
6.1 Have External Conditions Changed Since the Remedy?
This section evaluates if conditions external to the remedy have changed at the Whitewood Creek
Superfund site since the selection of the remedy. Changes in land use, known contaminants,
sources of contaminants, exposure pathways, hydrologic or hydrogeological conditions at the site
are evaluated in the following subsections.
6.1.1 Changes in Land Use
Based on the site inspections and site interviews no changes were identified in land use at the
Whitewood Creek site. Additionally, no planned changes in the future use of the Site were
identified..
6.1.2 Changes in Known Contaminants, Sources and Pathways
Changes in Known Contaminants
No known changes in exposure pathways were identified as part of the five-year review.
Changes in Known Sources
No changes in known sources of contaminants were identified during the five-year review.
Erosion of tailings in the stream banks and floodplain continues to be a source of contaminants
for Whitewood Creek.
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Changes in Known Pathways
No known changes in exposure pathways were identified as part of the five-year review.
6.1.3 Changes in Known Hydrologic or Hydrogeologic Conditions
No known changes in hydrologic or hydrogeologic conditions were identified as part of the five-
year review.
6.2 Has the Remedy Been Implemented in Accordance with Decision Documents?
This section evaluates if the remedy, including institutional controls, and its subsequent operation
and maintenance are implemented in accordance with project plans and are effective. Access and
institutional controls, remedy performance, adequacy of system operations/O&M requirements,
optimization, and early indications of potential remedy failure are evaluated in the following
subsections.
6.2.1 Health and Safety Plan (HASP) and Contingency Plan
A HASP and Contingency Plan were developed and were in place during remedial activities at the
Site. These plans were sufficient to control risks that may have occurred during remedial
activities.
6.2.2 Access and Institutional Controls
All institutional controls at the Site, including contamination and floodplain boundary
determination, county land use ordinances and state well ban regulations, annual educational
program, surface water monitoring, residential flood monitoring and five-year review verification
sampling program, are all currently in place. They have been implemented as part of the remedy
selected in the ROD and in accordance with the Site Institutional Control Plan.
Contamination and Floodplain Boundary Determination
The tailings deposit areas, tailings impacted soils and 100 year floodplain boundaries were
delineated during 1991 to 1992 and approved by USEPA in 1993. These boundaries were used in
the enactment of the county land use ordinances institutional control.
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Future Development Restrictions
County Land Use Ordinances
Land use ordinances restricting development on tailings deposits and in tailings impacted areas
within the Site were adopted by Butte, Meade and Lawrence Counties in 1993 and 1994. These
institutional controls remain in place in each of the counties.
Instances of unauthorized development within the Tailings Impacted Areas of the Site reported
during Site interviews (Sections 5.2.2 and 5.2.5) suggest that this institutional control is not
functioning effectively. By county ordinance, residential developments within the Tailings
Impacted Areas of the Site are allowed only in locations where soil concentrations are below the
100 ppm arsenic soil action level. Developers are required to demonstrate that their building sites
have arsenic levels below 100 ppm by soil sampling. When arsenic concentrations are determined
to be greater than 100 ppm in soil at a building site, they must be reduced by soil tillage or soil
covering before development can occur (WDC, 1994b).
Development was reported to occur within the 100 ppm tailings impacted areas at two residential
properties (Crowser and Thompson) without the prior application or soil sampling required by the
county ordinances. Sampling results were not available for either of these properties during the
site interviews. Therefore, it is unknown if the arsenic concentration in the soils at these
properties is below or above the residential soil action level.
Two additional properties (Berger and an Unknown Property "across the Creek from the
Holsclaw property") are reported to have been developed during this review. Information on the
location of these activities is not available to determine if they occurred in the tailings impacted
areas of the Site. Thus, these properties may or may not be in compliance with applicable county
development guidelines and the residential soil action level.
Based on the information available during this review summarized above, this institutional control
is not consistently functioning effectively to limit residents' exposures to arsenic impacted soils.
State Well Ban Regulation
The state well ban regulation prohibiting the construction of wells for residential or agricultural
uses in the 100 year floodplain, unless a variance has been granted by the State Chief Engineer,
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remains in place. Several variances have been granted for construction of wells within the 100
year floodplain (Section 4.3.3) since the implementation of the remedy. For each variance, the
wells were constructed to prevent contamination of groundwater from the tailings deposits,
consistent with the well ban regulation. Although a well was reported to have been installed at
the Thompson property (Section 5.2.2), based on the information available from the SD DENR
Water Rights Program (SD DENR, 2002), the well does not appear to be located within the 100
year floodplain of Whitewood Creek. Information on wells installed within the 100 year
floodplain without a variance from SD DENR were not uncovered during this five-year review.
Thus, based on the available information, the State well ban regulation appears to be functioning
effectively.
Educational Program
Educational materials were distributed on an annual basis during the period 1993 through 2001 as
required by the ROD and in accordance with the Institutional Controls Plan. This institutional
control remains in place.
The potential pathways hypothesized as the sources of recontamination of the Holsclaw property
suggest that this institutional control is not entirely effective. One of the objectives of the annual
educational program is to inform residents about ways to minimize personal exposures.
Recontamination of garden and driveway materials discovered during five-year review verification
sampling are speculated to be the result of the importation of contaminated materials into the
garden, and by tracking tailings materials onto the property from driving through tailings impacted
areas (Chadwick et al., 1997). An effective education program may have eliminated these
pathways as potential sources of re-contamination.
Further, the educational materials remind residents of the development restrictions that are
applicable for building within Tailings Impacted Areas of the Site. As previously mentioned, there
are instances of development in the Tailings Impacted Areas without the prior applications or soil
sampling required by county ordinances. An effective education program addressing the building
requirements within the Site may have worked to prevent or reduce the number of these
developments that occurred without following county ordinance requirements.
Additionally, the content and type of educational materials distributed annually do not seem to
vary significantly from year-to-year (Attachment 4-2). A more effective implementation method
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may be to vary the content and type of education materials on a yearly basis to ensure that the
information is effectively communicated and not ignored because it is the same material over and
over.
Surface Water Monitoring
Surface water monitoring activities have been ongoing at the Site since the program's
implementation in 1993. This institutional control remains in place.
The program is effective in collecting data to monitor trends of arsenic concentrations in surface
water over time and during various flow conditions.
Residential Flood Monitoring
Plans for resampling remediated properties after flood events and as part of the five-year review
are in place as part of the institutional control plan.
No residential properties are reported to be impacted by the flooding events since the
implementation of the remedy. Therefore soil sampling has not been required. Thus, the
effectiveness of the flood monitoring program cannot be evaluated.
6.2.3 Remedy Performance
As discussed in Sections 4.3.4 (Post-Closure Residential Soil Sampling and Remediation) and in
Section 5.6.1 (Residential Verification Sampling) the residential remediation portion of the
remedy is in place and remains effective. Verification sampling activities at remediated residences
within the Site confirmed concentrations of arsenic in residential soils remained below the Site
action level of 100 ppm, and properly identified properties with concentrations above the action
level for remediation.
Instances of unauthorized development within the 100 ppm Tailings Impacted Area suggest that
the county land use ordinances and the annual education program institutional controls are not
functioning effectively. Based on the available information, the state well ban regulation is
functioning effectively.
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6.2.4 Adequacy of System Operations/O&M
System O&M activities include the long-term maintenance of several of the Site institutional
control items. The adequacy of the institutional controls are evaluated in Sections 6.2.2 and
6.2.3. Brief summaries of the institutional control items evaluated in previous sections are
included below with the evaluation of other O&M activities.
Surface Water Monitoring
As summarized in Section 4.3.1, surface water samples have been collected during various flow
conditions throughout the period of 1993 to 2001 as outlined in Addendum B of the O&M Plan
(WDC, 1994b). Although in some years, samples were collected representing only three of the
four required flow conditions, the maintenance of this institutional control is generally adequate
for the long-term monitoring of arsenic concentrations during varying flow conditions in the
surface water of Whitewood Creek
Annual Education Program
As discussed in Section 4.3.1 educational materials have been distributed annually, during the
period of 1993 to 2001, in accordance with the Site O&M Plan (WDC, 1994b). The annual
maintenance of this institutional control is adequate.
Future Development Restrictions-Annual Review of Residential Building Activity
As reported in Section 4.3.3, the findings from the review of residential development activities
within the Site have been reported in the Monthly/Quarterly Reports in accordance with the O&M
Plan (WDC, 1994b). Sections 5.2.2 and 5.2.5 reported development activities that have occurred
within the Site since the implementation of the remedy. Development occurred on five different
properties, two of which (Crowser and Thompson properties) were located within the tailings
impacted areas without prior application or sampling.
Of these five instances of development, only two were identified by the available Quarterly
Reports (the Crowser and Berger properties). This O&M activity appears to be adequate in
identifying some, but not all, of the residential building activities within the Site.
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Based on a review of the variance information from the South Dakota Water Rights Program, the
state well ban regulation appears to be functioning effectively. Wells installed within the 100 year
floodplain were constructed to prevent contamination from tailings materials and to prevent
groundwater pollution.
Post-closure Residential Site Soil Sampling Activities and Remediation
Flood Impact Soil Sampling
A plan for resampling residential properties following flood events is in place. No residential
properties are reported to be impacted by flooding events since the implementation of the remedy.
Thus, the adequacy of the maintenance of this institutional control item cannot be evaluated.
Five-Year Review Verification Sampling
Plans for resampling remediated properties as part of the five-year review are in place as part of
the institutional control plan.
The five-year review verification sampling conducted in 1996 was effective in confirming that
concentrations of arsenic in residential soils remained below the site action level. It appropriately
identified one property with concentrations above the action level for re-remediation. This O&M
activity is adequate in ensuring that residential soil concentrations of arsenic remain below the Site
soil action level.
Verification sampling was also conducted in October 2001 (HMC, 2001a). However, the results
from this sampling event were not available for inclusion in this five-year review report. The next
five-year review of the Site will present the results from the October 2001 sampling event.
Residential Soil Remediation (as necessary)
One property was identified during five-year review verification sampling, that required
remediation. This property was remediated in accordance with Site project plans so arsenic
concentrations were below the soil action level of 100 ppm arsenic. The maintenance of this
institutional control is adequate in limiting residents' exposure to arsenic in soil.
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Disposal Site Monitoring
Annual inspections of the disposal site have been adequate in identifying conditions needing
repair. Maintenance of vegetative cover and rip-rap at the disposal site have been conducted as
needed in order to maintain the conditions specified in the Transportation and Disposal Plan (see
Section 4.3.5).
Reporting
Quarterly Reports
Quarterly reports of Site O&M activities and the Five-Year Review report of the Site remedy
have been submitted in accordance with the Site O&M Plan (WDC, 1994b). This O&M activity
is adequate in reporting the respective activities at the Site.
Five-Year Review
Homestake initiated the current five-year review in accordance with the Site O&M Plan (WDC,
1994b).
6.2.5 Need for Optimization
Based on a review of the remedy, the following institutional controls require optimization:
Follow up with property owners where development has occurred to ensure that
these activities are in compliance with county development guidelines and state
well regulations, where applicable.
Information on/review of the county ordinance development requirements with
both residents and county officials, and the affected areas of the Site were these
guidelines are applicable.
6.2.6 Early Indicators of Potential Remedy Failure
O&M costs can be an indicator of potential remedy failure. Large variances in O&M costs may
indicate frequent equipment breakdowns and repairs, suggesting that contaminants are not being
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contained and/or treated as required. Costs that are unusually high or inconsistent with original
cost estimates may indicate a potential problem for maintaining long-term O&M activities.
Cost information was not available for consideration or evaluation as an indicator of potential
remedy failure. Thus, conclusions regarding potential remedy failure based on operations and
maintenance costs could not be reached during this review.
6.3 Has Any Risk Information Changed Since the Remedy was Selected?
This section evaluates changes in regulations or other risk information that have changed since the
implementation of the remedy. Changes in ARARs, human health and ecological risk information
are evaluated in the following subsections.
6.3.1 Changes in ARARs
This five-year review identified changes in both state and federal drinking water, surface water
quality criteria, state groundwater quality criteria, ambient air quality standards and in solid waste
management regulations that occurred since the signing of the ROD.
Changes to both federal and/or state drinking water standards, surface water quality criteria,
groundwater quality standards and ambient air quality standards have occurred, some increasing
and some decreasing the stringency of these regulations for various chemicals. An ARAR waiver
was invoked for the arsenic MCL in groundwater and the arsenic surface water AWQC based on
the technical impracticability of meeting these standards. Thus, the changes in the arsenic
regulations do not affect the protectiveness of the remedy. Based on the findings of the risk
recalculation and assessment (see Attachment 5-3) and the review of surface water data (Section
5.6), concentrations of chemicals in surface water are considered by EPA to be protective of
human health and the environment. Groundwater and ambient air data were not available to
review compliance with applicable state and federal standards to ensure protectiveness. However,
the contaminated downgradient alluvial aquifer is not a current source of drinking water (USEPA,
1990) and potential ambient air exceedences from Site operations were likely greatest during the
remedial action. Based on this, the changes in chemical-specific ARARs that have occurred since
the ROD do not affect the protectiveness of the remedy.
Modifications to existing solid waste management regulations that pertain to the disposal facility
currently do not affect the protectiveness of the remedy. However, should the disposal facility
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become active in the future, these changes in solid waste management regulations may be relevant
and appropriate and may affect the protectiveness of the remedy.
6.3.2. Changes in Risk Information
Human Health
Although there have been some changes in the toxicity factors and exposure parameters
recommended by USEPA for evaluating cancer and noncancer risks from arsenic (SRC, 2001a),
USEPA considers the soil action level of 100 mg/kg to still be adequately protective of human
health.
Risks to recreational fishermen from ingestion of arsenic in fish from Whitewood Creek were
evaluated (SRC, 2002), and were below USEPA's usual target risk range for cancer and
non-cancer effects at Superfund sites (USEPA, 1991).
Ecological
An ecological risk assessment was conducted for the Site to assess whether existing site
conditions do or do not pose unacceptable risks to ecological receptors. Based on an evaluation
of the weight of evidence across all available lines of evidence, EPA has concluded that mining-
related chemicals probably are causing some toxicological effects on both the aquatic and the
terrestrial ecosystems, but that these effects are generally low level and are probably not sufficient
to cause substantial disruption of aquatic or terrestrial ecosystem function or viability. Based on
this, the current remedy is considered to be adequate for protection of ecological receptors and
the environment.
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7.0 DEFICIENCIES
This section identifies shortcomings, if any, in the current site operations that prevent the remedy
from being protective of human health and the environment. The deficiencies discovered during
this five-year review are noted in the table below. None of these are sufficient to warrant a
finding of not protective, as long as corrective actions are taken.
Deficiencies Identified ;is Pari of (Ik- ri\c-Ycar Rc\ic\\
Deficiencies
(iiiTcnlh Alice Is
Prolcc(i\cncss (Y/\)
Future Development Restrictions
Two instances of unauthorized building in Tailings Impacted Areas
N
Butte County missing site reference map of tailings impacted
areas
N
Annual Resident Educational Program
Two instances of unauthorized building in Tailings Impacted Areas
N
Information addresses the potential pathways suspected to contribute to the
recontamination of Holsclaw property
N
7.1 Deficiencies in the Future Development Restrictions
The two instances of unauthorized development in the Tailings Impacted Area of the Site
suggests that the county land use ordinances are not consistently effective in controlling arsenic
exposure through restricting development activities. Additionally, only one of the two
unauthorized development instances was reported during the quarterly review of residential
building activities within the Site, suggesting that this O&M activity is not consistently effective at
identifying building activities at the Site to ensure compliance with county ordinances.
One minor deficiency associated with county land use ordinances was identified during Site
interviews. Butte County was missing a reference map of the delineated boundaries of the tailings
deposits, tailings impacted areas, and 100 year floodplain.
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7.2 Deficiencies in the Annual Resident Education Program
The two instances of unauthorized development in the tailings impacted areas suggests that this
institutional control is not functioning effectively to inform residents of the procedures for
development within the Site.
Additionally, the potential sources and pathways that were hypothesized to contribute to the
recontamination of the Holsclaw property are addressed in the educational materials distributed to
residents. Thus, this information may not be effective in informing residents of how to reduce
exposure and prevent contamination of their properties.
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8.0
RECOMMENDATIONS AND REQUIRED ACTIONS
This section specifies the required and suggested improvements to current site operations to
address the deficiencies that currently affect protectiveness. These recommendations are
summarized in the following table along with the parties responsible for actions, milestone dates,
and agencies with oversight authority.
Recommendations iinri Rc(|iiircd Actions Identified During (lie l"i\c-Ycar Rc\ic\\
Kecom meiithil ions/
Rc(|iiircd Actions
Parl\
Responsible
Owrsighl
Aticno
Milestone
Date
Required
Actions:
( urrcnlh AITeels
Protect i\cncss
(Y/N)
County Land Use Ordinances
Prepare updated maps of each
property affected by County
Ordinances showing property use,
tailings deposits, and tailings
impacted (100 ppm arsenic areas).
Distribute to property owners,
county officials, and USEPA.
Homestake
USEPA
June 30,
2003
N
Notify County of any development
activities in the tailings-impacted
areas.
Homestake
USEPA
Ongoing
N
Follow up with property owners
where development was reported to
have occurred to ensure that they are
in compliance with county ordinance
guidelines and state well ban
regulations.
Butte,
Meade and
Lawrence
Counties
USEPA
June 30,
2003
N
Supply Butte County with proper
maps and reference materials
Homestake
USEPA
June 30,
2003
N
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Recommendations and Required Actions Identified During the Five-Year Review
Recommendations/
Required Actions
Party
Responsible
Oversight
Agency
Milestone
Date
Required
Actions:
Currently Affects
Protectiveness
(Y/N)
Annual Resident Education Program
Modify annual information packet to
include a point of contact at the
appropriate County Offices and also
an awareness of county development
ordinances as a "Site Resident's
Role"
Homestake
USEPA
June 30,
2003
N
8.1 Recommendations for Future Development Restrictions
8.1.1 Updated Maps
The site interview portion of this five-year review identified residential development activities
within the Site. Some of these occurred within the 100 ppm tailings impacted area without prior
application or compliance with county development guidelines and information was not available
for some of the other development activities to determine if they were in compliance with county
guidelines. It is recommended that updated maps of the individual residential properties affected
by the county ordinances be prepared and distributed to the residents, county officials and
USEPA. These maps will detail the current property use and high-use areas, tailings deposit areas
and Tailings Impacted (100 ppm arsenic) Areas, as applicable to each residence. The maps will
serve as informational tools to residents and county officials on areas within a property that are
governed by the county land use ordinances and development guidelines. These maps can then be
submitted to the counties, as necessary, by the residents as part of any building permit applications
for development activities on their properties. The maps will also inform residents of areas where
arsenic concentrations are above the soil action level and the location of tailings deposits in order
to limit exposure and activities in these areas. This may help to limit the possibility of
recontamination of residential properties by the tracking or incidental importation of contaminated
materials or tailings; speculated as a potential source of recontamination at the Holsclaw property
(Chadwick et al., 1997) during the five-year review.
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8.1.2 Notification of Development Activities
Homestake periodically has personnel in the area of the Site impacted by fluvial tailings and
covered by the county ordinances governing development in these areas. In the event that
Homestake becomes aware of development in the tailings-impacted areas, the appropriate County
agency should be notified to ensure compliance with applicable ordinances. A brief narrative
description of these periodic visits and contact with the respective county agency shall be included
in the quarterly monitoring report submitted to USEPA. This narrative description of
development activities within the Site is currently required as part of Site O&M activities (WDC,
1994b).
8.1.3 Follow-up Visits With Properties Identified During the Five-Year Review
The site interview portion of this five-year review identified several properties where development
activities had occurred. Limited information on the details of these activities were available in this
review. To ensure that these building activities are in compliance with applicable county
ordinance development guidelines and state well ban regulations, it is recommended that
representatives from the appropriate county agencies visit these four properties (Crowser,
Thompson, Berger and the Unknown Property located "across the Creek from the Holsclaw
property") to follow up with and gain additional information from the residents on their
development activities. It is recommended that the results from these follow-up visits (including
soil sampling results) be submitted to SD DENR and USEPA.
8.1.4 Provide Maps and Reference Materials to Counties
At the time of the interviews with government officials, USEPA identified the need to supply
Butte County officials with the proper maps and reference materials in order to provide
information to individuals considering development within the Site. Follow-up with Lawrence
and Meade County officials may also be suggested to ensure that they have sufficient copies of
maps and reference materials.
8-3
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8.2
Recommendations for the Annual Resident Education Program
The annual information sheet sent to area residents shall be modified to include a point of contact
for the appropriate County offices in the section titled "County Ordinances". Additionally, the
"Site Resident's Role" section shall be modified to include an awareness of the county ordinances
governing development in tailings-impacted areas.
8-4
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9.0 PROTECTIVENESS STATEMENT(S)
The protectiveness of the remedy to humans is discussed in two sections: residential remediation
and institutional control implementation. The protectiveness of the remedy to the environment is
discussed in a third section.
9.1 Residential Remediation
Residential remediation activities are considered to remain protective of human health. The
current residential soil action level for arsenic is considered to still be adequately protective of
human health. Verification sampling results indicate that the residential remediation portion of the
remedy remains effective. Arsenic concentrations within the high use areas of residential
properties within the Site remain below the soil action level of 100 mg/kg. In the instance where
arsenic concentrations were found to exceed the soil action level, the soils were remediated in
accordance with project plans.
9.2 Institutional Control Implementation
The institutional controls implemented at the Site (including land-use restrictions and other
controls such as the annual educational program and surface water monitoring) are considered to
remain protective of human health and the environment, provided that the corrective actions
outlined in Section 8.0 (Recommendations and Required Actions) are taken. Contamination and
floodplain boundaries have been determined and are incorporated into county ordinances to
restrict development in certain areas of the Site. The state well ban regulation remains in place
and is functioning effectively. The surface water monitoring program, annual resident educational
program, flood monitoring and five-year verification sampling programs, remain in place and are
functioning effectively. Annual inspections of the disposal site have effectively identified and
addressed conditions that have needed repair. Incorporating the recommendations identified in
Section 8.0 into the annual resident education program and in increasing the implementation and
enforcement of the county land use ordinance requirements will ensure that these institutional
controls are consistently functioning effectively and are protective of human health.
9.3 Protection of the Environment
The current remedy is considered to be adequate for protection of ecological receptors and the
environment. Based on an evaluation of the weight of evidence across all available lines of
9- 1
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evidence, mining-related chemicals probably are probably causing some effects on both the
aquatic and the terrestrial ecosystems, but these effects are generally low level and are not likely
to be sufficient to cause substantial disruption of aquatic or terrestrial ecosystem function or
viability.
9.4 Protectiveness Statement
The remedy for the Site, as long as corrective actions are taken, is considered to remain protective
of human health and the environment.
9-2
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10.0 NEXT REVIEW
The Whitewood Creek Superfund Site requires ongoing five-year reviews. These reviews will be
required, as stated by the NCP, as long as hazardous substances, pollutants or contaminants
remain at this Site above levels allowing for unlimited use and unrestricted exposure.
The next review will be conducted within five years of the completion of this five-year review
report, which is five years from the date listed on this report's signature cover page. This is a
slight modification from the date outlined in the O&M Plan of January 31, 2007. The schedule
for the Five-Year Review data collection activities remains as outlined in the O&M Plan, to be
completed by September 25, 2006, the fifteen year anniversary of the remedial action start date.
10- 1
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11.0 REFERENCES
Bailey, R.G. 1982. Classification systems for habitat and ecosystems. Pages 16-26. In Research
on Fish and Wildlife Habitat. USEPA 600/8-82-022 (as cited in Chadwick et al. 1997)
Bergeland ME, GR Rugh, RL Stack and RJ Emerick. 1976. Arsenic Toxicosis in Cattle
Associated With Soil and Water Contamination from Mining Operations. In Proceedings of the
19th Annual Meeting of the American Association of Veterinary Laboratory Diagnosticians (as
cited in USEPA 1989a).
Chadwick Ecological Consultants Inc. (Chadwick), KRW Consulting, Inc., Remediation
Technologies, Inc., and Times Limited. 1997. Status Report and Technical Support Document
for the 1997 5-Year Review, Whitewood Creek Superfund Site. Prepared for Homestake Mining
Company, January 31, 1997.
Cherry JA, FMM Morel, JV Rouse, JL Schnoor, and MG Wolman. 1985. Hydrogeochemistry of
Sulfide and Arsenic-Rich Tailings and Alluvium Along Whitewood Creek, South Dakota. US
Geological Survey, Rapid City, South Dakota.
Environ Corp (Environ). 1985. Assessment of Exposure and Possible Effects on Human Health
of Gold Mine Tailings in the Whitewood Creek Area of South Dakota. Prepared by Environ,
Corp for Homestake Mining Corporation. April 10, 1985. Draft.
Environmental Response Team (ERT). 1999a. Quality Assurance Workplan Whitewood Creek
Ecological Risk Assessment, Lead, South Dakota. Prepared by Mark Sprenger (U.S. USEPA
Environmental Response Team) and Barry Forsythe (Environmental Response Team Center).
February.
Environmental Response Team (ERT). 1999b. Supplemental to Quality Assurance Work Plan
Whitewood Creek Ecological Risk Assessment, Lead, South Dakota. Prepared by Mark
Sprenger, Environmental Response Team, Edison NJ, and Barry Forsythe, ERTC/REAC. June.
Environmental Response Team (ERT). 1999c. Draft Interim Report, March 1999 Aquatic
Sampling Activities Whitewood Creek Ecological Risk Assessment, Lead, South Dakota.
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Prepared for U. S. EPA ERTC by Lockhead Martin under U. S. EPA Work Assignment No.:
0-023, Lockheed Martin Work Order No.: R1A00023, U.S. EPA Contract No.: 68-C99-223.
September.
Environmental Response Team (ERT). 2000. Draft Interim Report, 1999 Terrestrial Sampling
Activities Whitewood Creek Ecological Risk Assessment, Lead, South Dakota. Prepared for
U.S. EPA ERTC by Lockhead Martin under U.S. EPA Work Assignment No.: 0-023, Lockheed
Martin Work Order No.: R1A00023, U.S. EPA Contract No.: 68-C99-223. February.
FMG, Inc. (FMG). 1992. Construction Completion Report for Residential Remediation
Whitewood Creek Superfund Site Lawrence, Meade, and Butte Counties, South Dakota. FMG,
In. Rapid City, South Dakota. December 21,1992.
FMG, Inc. (FMG). 1993. Construction Completion Report Addendum for The Disposal Site,
Topsoil and Topsoil Subgrade Borrow Site, and the Temporary Stream Crossing at the
Whitewood Creek Superfund Site. FMG, Inc. Rapid City, South Dakota. February 4.
Fox Consultants, Inc. 1984a. Whitewood Creek Study, Phase I. Prepared for the South Dakota
Department of Water and Natural Resources Office of Air Quality and Solid Waste. April 16,
1984
Fox Consultants, Inc. 1984b. Whitewood Creek Study, Phase II. Prepared for the South Dakota
Department of Water and Natural Resources Office of Air Quality and Solid Waste, Homestake
Mining Company and the United States Environmental Protection Agency. November 1984.
George. 1997. Response to Four General Comments Addressed in EPA's Letter Dated
September 18, 1997 Providing Comments on Homestake's Five Year Review and Status Report
for the Whitewood Creek Superfund Site. Gerald F. George, Cambell and Graves (Counsel for
Homestake Mining Company of California). Walnut Creek, California. November 7.
Goddard, K.E. 1989. Composition, Distribution, and Hydrologic Effects of
Contaminated Sediments Resulting from the Discharge of Gold Milling Wastes to Whitewood
Creek at Lead and Deadwood, South Dakota. USGS. Water Resources Investigation Report
87-4051.
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Goddard K.E., A.J. Horowitz, and C. K. Shearer. 1988. Distribution of Solid-Phase Arsenic and
Trace Elements in Bottom and Suspended Sediments, Whitewood Creek and the Belle Fourche
and Cheyenne Rivers, Western South Dakota. USGS. Water Resources Investigation Report
87-764. Pages 13-18.
Herricks, E.E. 1982. Bioassessment of Whitewood Creek Lawrence and Meade Counties, South
Dakota. Prepared for the Homestake Mining Company, Lead, South Dakota.
Hess, W.L., R.L. Brown and J.F. Heisinger. 1975. Mercury Contamination of Birds from a
Polluted Watershed. Journal of Wildlife Management, 39 (2):299-304.
Homestake Mining Company (HMC). 2001a. Whitewood Creek Superfund Site Quarterly
Report, 4th Quarter 2001 (Report Number 34). Homestake Mining Company, San Francisco
California.
Homestake Mining Company (HMC). 2001b. Whitewood Creek Superfund Site Quarterly
Report, 3rd Quarter 2001 (Report Number 33). Homestake Mining Company, San Francisco
California.
Homestake Mining Company (HMC). 2001c. Whitewood Creek Superfund Site Quarterly
Report, 2nd Quarter 2001 (Report Number 32). Homestake Mining Company, San Francisco
California.
Homestake Mining Company (HMC). 2001c. Whitewood Creek Superfund Site Quarterly
Report, 1st Quarter 2001 (Report Number 31). Homestake Mining Company, San Francisco
California.
Homestake Mining Company (HMC). 2000. Whitewood Creek Superfund Site Quarterly
Report, 2nd Quarter 2000 (Report Number 28). Homestake Mining Company, San Francisco
California.
Homestake Mining Company (HMC). 1999a. Whitewood Creek Superfund Site Quarterly
Report, 4th Quarter 1998 (Report Number 22). Homestake Mining Company, San Francisco
California. January 1999.
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Homestake Mining Company (HMC). 1999b. Whitewood Creek Superfund Site Quarterly
Report, 3rd Quarter 1999 (Report Number 25). Homestake Mining Company, San Francisco
California. October 1999.
Homestake Mining Company (HMC). 1999b. Whitewood Creek Superfund Site Quarterly
Report, 2nd Quarter 1999 (Report Number 24). Homestake Mining Company, San Francisco
California. July 1999.
Homestake Mining Company (HMC). 1999c. Whitewood Creek Superfund Site Quarterly
Report, 1st Quarter 1999 (Report Number 23). Homestake Mining Company, San Francisco
California. April 1999.
Homestake Mining Company (HMC). 1998a. Whitewood Creek Superfund Site Quarterly
Report, 3rd Quarter 1998 (Report Number 21). Homestake Mining Company, San Francisco
California. October 1998.
Homestake Mining Company (HMC). 1998b. Whitewood Creek Superfund Site Quarterly
Report, 4th Quarter 1997 (Report Number 18). Homestake Mining Company, San Francisco
California. January 1998.
Homestake Mining Company (HMC). 1997a. Whitewood Creek Superfund Site Quarterly
Report, 3rd Quarter 1997 (Report Number 17). Homestake Mining Company, San Francisco
California. October 31, 1997.
Homestake Mining Company (HMC). 1997b. Whitewood Creek Superfund Site Quarterly
Report, 2nd Quarter 1997 (Report Number 16). Homestake Mining Company, San Francisco
California. July 29, 1997.
Homestake Mining Company (HMC). 1997c.
Report, 1st Quarter 1997 (Report Number 15).
California. April 30, 1997.
Homestake Mining Company (HMC). 1997d.
Report, 4th Quarter 1996 (Report Number 14).
California. January 31, 1997.
Whitewood Creek Superfund Site Quarterly
Homestake Mining Company, San Francisco
Whitewood Creek Superfund Site Quarterly
Homestake Mining Company, San Francisco
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Homestake Mining Company (HMC). 1996a. Whitewood Creek Superfund Site Quarterly
Report, 3rd Quarter 1996 (Report Number 13). Homestake Mining Company, San Francisco
California. October 31, 1996.
Homestake Mining Company (HMC). 1996b. Whitewood Creek Superfund Site Quarterly
Report,(Report Number 12). Homestake Mining Company, San Francisco California. July 31,
1996.
Homestake Mining Company (HMC). 1996c. Whitewood Creek Superfund Site Quarterly
Report,(Report Number 11). Homestake Mining Company, San Francisco California. April 30,
1996.
Homestake Mining Company (HMC). 1996d. Whitewood Creek Superfund Site Quarterly
Report,(Report Number 10). Homestake Mining Company, San Francisco California. January
31, 1996.
Homestake Mining Company (HMC). 1995a. Whitewood Creek Superfund Site Quarterly
Report, 3rd Quarter 1995 (Report Number 9). Homestake Mining Company, San Francisco
California. October 31, 1995.
Homestake Mining Company (HMC). 1995b. Whitewood Creek Superfund Site Quarterly
Report, 2nd Quarter 1995 (Report Number 8). Homestake Mining Company, San Francisco
California. July 31, 1995.
Homestake Mining Company (HMC). 1995c. Whitewood Creek Superfund Site Quarterly
Report, 1st Quarter 1995 (Report Number 7). Homestake Mining Company, San Francisco
California. April 30, 1995
Homestake Mining Company (HMC). 1995d. Whitewood Creek Superfund Site Final Monthly
Progress Report, (Report Number 53). Homestake Mining Company, San Francisco California.
March 10, 1995.
Homestake Mining Company (HMC). 1995e. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 52). Homestake Mining Company, San Francisco California.
February 10, 1995.
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Homestake Mining Company (HMC). 1995f. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 51). Homestake Mining Company, San Francisco California.
January 10, 1995.
Homestake Mining Company (HMC). 1995g. Whitewood Creek Superfund Site Quarterly
Report, 4th Quarter 1994 (Report Number 6). Homestake Mining Company, San Francisco
California. January 31, 1995.
Homestake Mining Company (HMC). 1994a. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 50). Homestake Mining Company, San Francisco California.
December 9, 1994.
Homestake Mining Company (HMC). 1994b. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 49). Homestake Mining Company, San Francisco California.
November 10, 1994.
Homestake Mining Company (HMC). 1994c. Whitewood Creek Superfund Site Quarterly
Report, (Report Number 5). Homestake Mining Company, San Francisco California. October
31, 1994.
Homestake Mining Company (HMC). 1994d. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 48). Homestake Mining Company, San Francisco California.
October 10, 1994.
Homestake Mining Company (HMC). 1994e. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 47). Homestake Mining Company, San Francisco California.
September 10, 1994.
Homestake Mining Company (HMC). 1994f. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 46). Homestake Mining Company, San Francisco California.
August 10, 1994.
Homestake Mining Company (HMC). 1994g. Whitewood Creek Superfund Site Quarterly
Report,(Report Number 4). Homestake Mining Company, San Francisco California. July 31,
1994.
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Homestake Mining Company (HMC). 1994h. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 45). Homestake Mining Company, San Francisco California.
July 8, 1994.
Homestake Mining Company (HMC). 1994i. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 44). Homestake Mining Company, San Francisco California.
June 10, 1994.
Homestake Mining Company (HMC). 1994j. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 43). Homestake Mining Company, San Francisco California.
May 10, 1994.
Homestake Mining Company (HMC). 1994k. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 42). Homestake Mining Company, San Francisco California.
April 8, 1994.
Homestake Mining Company (HMC). 19941. Whitewood Creek Superfund Site Quarterly
Report, (Report Number 3). Homestake Mining Company, San Francisco California. April 29,
1994.
Homestake Mining Company (HMC). 1994m. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 41). Homestake Mining Company, San Francisco California.
March 10, 1994.
Homestake Mining Company (HMC). 1994n. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 40). Homestake Mining Company, San Francisco California.
February 10, 1994.
Homestake Mining Company (HMC). 1994o. Whitewood Creek Superfund Site Quarterly
Report,(Report Number 2). Homestake Mining Company, San Francisco California. January 28,
1994.
Homestake Mining Company (HMC). 1994p. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 39). Homestake Mining Company, San Francisco California.
January 10, 1994.
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Homestake Mining Company (HMC). 1993a. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 38). Homestake Mining Company, San Francisco California.
December 10, 1993.
Homestake Mining Company (HMC). 1993b. Whitewood Creek Superfund Site Quarterly
Report, (Report Number 1). Homestake Mining Company, San Francisco California. November
18, 1993.
Homestake Mining Company (HMC). 1993c. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 37). Homestake Mining Company, San Francisco California.
November 10, 1993.
Homestake Mining Company (HMC). 1993d. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 36). Homestake Mining Company, San Francisco California.
October 8, 1993.
Homestake Mining Company (HMC). 1993e. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 35). Homestake Mining Company, San Francisco California.
September 10, 1993.
Homestake Mining Company (HMC). 1993f. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 34). Homestake Mining Company, San Francisco California.
August 10, 1993.
Homestake Mining Company (HMC). 1993g. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 33). Homestake Mining Company, San Francisco California.
July 9, 1993.
Homestake Mining Company (HMC). 1993h. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 32). Homestake Mining Company, San Francisco California.
June 10, 1993.
Homestake Mining Company (HMC). 1993i. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 31). Homestake Mining Company, San Francisco California.
May 10, 1993.
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Homestake Mining Company (HMC
Progress Report, (Report Number 30
April 10, 1993.
Homestake Mining Company (HMC
Progress Report, (Report Number 29
March 10, 1993.
Homestake Mining Company (HMC
Progress Report, (Report Number 28
February 10, 1993.
Homestake Mining Company (HMC
Progress Report, (Report Number 27
January 10, 1993.
Homestake Mining Company (HMC
Progress Report, (Report Number 26
December 10, 1992.
Homestake Mining Company (HMC
Progress Report, (Report Number 25
November 10, 1992.
Homestake Mining Company (HMC
Progress Report, (Report Number 24
October 10, 1992.
Homestake Mining Company (HMC
Progress Report, (Report Number 23
September 10, 1992.
Homestake Mining Company (HMC
Progress Report, (Report Number 22
August 10, 1992.
1993j. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1993 k. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
19931. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1993m. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1992a. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1992b. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1992c. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1992d. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1992e. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
11-9
-------
Homestake Mining Company (HMC
Progress Report, (Report Number 21
July 10, 1992.
Homestake Mining Company (HMC
Progress Report, (Report Number 20
June 10, 1992.
Homestake Mining Company (HMC
Progress Report, (Report Number 19
May 10, 1992.
Homestake Mining Company (HMC
Progress Report, (Report Number 18
April 10, 1992.
Homestake Mining Company (HMC
Progress Report, (Report Number 17
March 10, 1992.
Homestake Mining Company (HMC
Progress Report, (Report Number 16
February 10, 1992.
Homestake Mining Company (HMC
Progress Report, (Report Number 15
January 10, 1992.
Homestake Mining Company (HMC
Progress Report, (Report Number 14
December 10, 1991.
Homestake Mining Company (HMC
Progress Report, (Report Number 13
November 10, 1991.
1992f. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1992g. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1992h. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1992i. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1992j. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1992k. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
19921. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1991a. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
1991b. Whitewood Creek Superfund Site Monthly
Homestake Mining Company, San Francisco California.
11 - 10
-------
Homestake Mining Company (HMC). 1991c. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 12). Homestake Mining Company, San Francisco California.
October 10, 1991.
Homestake Mining Company (HMC). 199Id. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 11). Homestake Mining Company, San Francisco California.
September 10, 1991.
Homestake Mining Company (HMC). 1991e. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 10). Homestake Mining Company, San Francisco California.
August 10, 1991.
Homestake Mining Company (HMC). 199If. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 9). Homestake Mining Company, San Francisco California.
July 10, 1991.
Homestake Mining Company (HMC). 1991g. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 8). Homestake Mining Company, San Francisco California.
June 10, 1991.
Homestake Mining Company (HMC). 1991h. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 7). Homestake Mining Company, San Francisco California.
May 10, 1991.
Homestake Mining Company (HMC). 1991i. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 6). Homestake Mining Company, San Francisco California.
April 10, 1991.
Homestake Mining Company (HMC). 199lj. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 5). Homestake Mining Company, San Francisco California.
March 10, 1991.
Homestake Mining Company (HMC). 1991k. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 4). Homestake Mining Company, San Francisco California.
February 10, 1991.
11 - 11
-------
Homestake Mining Company (HMC). 19911. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 3). Homestake Mining Company, San Francisco California.
January 10, 1991.
Homestake Mining Company (HMC). 1990a. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 2). Homestake Mining Company, San Francisco California.
December 10, 1990.
Homestake Mining Company (HMC). 1990b. Whitewood Creek Superfund Site Monthly
Progress Report, (Report Number 1). Homestake Mining Company, San Francisco California.
November 9, 1990.
ICF Incorporated (ICF). 1989a. Feasibility Study for Whitewood Creek, South Dakota,
CERCLA Site Volume I. Prepared for Homestake Mining Company by ICF Technology for
submission to USEPA Region VIII. December 8.
ICF Incorporated (ICF). 1989b. Feasibility Study for Whitewood Creek, South Dakota,
CERCLA Site, Volume II. Prepared for Homestake Mining Company by ICF Technology for
submission to USEPA Region VIII. December 3.
ICF Incorporated (ICF). 1989c. Subsection 1.7 of April 1989 Preliminary Draft of Feasibility
Study for Whitewood Creek, South Dakota, CERCLA Site. Prepared for Homestake Mining
Company by ICF Technology for submission to USEPA Region VIII. December 3.
ISSI Consulting Group, Inc. (ISSI). 1998. Screening Level Ecological Risk Assessment,
Whitewood Creek Site, Lead, South Dakota. Prepared by ISSI, Inc. for USEPA Region 8.
October.
Jacobs Engineering. 1989. Final Endangerment Assessment Summary Document for Whitewood
Creek Superfund Site. Prepared by Jacobs Engineering for USEPA Region VIII. July 1989.
South Dakota Department of Environment and Natural Resources (SD DENR). 2002. Personal
Communication. Ken Buehler, Water Rights Program. April 18, 2002.
Syracuse Research Corporation (SRC). 2001a. Whitewood Creek Five-Year Review Human
Health Risk Findings. Prepared by SRC for USEPA Region VIII. June 25, 2001.
11 - 12
-------
Syracuse Research Corporation (SRC). 2001b. Ecological Risk Assessment Whitewood Creek
Site Five Year Review Lead, South Dakota. Prepared by SRC for USEPA Region VIII. August
24, 2001.
Syracuse Research Corporation (SRC). 2002.
Health Risk Findings from Fish Consumption.
15, 2002.
Whitewood Creek Five-Year Review Human
Prepared by SRC for USEPA Region VIII. April
United States v. Homestake. 1991. Consent Decree, US vs Homestake Mining Company of
California, Civil Action No. 90-5101. Entered by US District Court for South Dakota on April 4,
1991.
United States Environmental Protection Agency (USEPA). 2001. Update of Ambient Water
Quality Criteria for Cadmium. Office of Water, EPA-822-R-01-001.
United States Environmental Protection Agency (USEPA). 1999a. Comprehensive Five-Year
Review Guidance. Office of Emergency and Remedial Response. USEPA, Washington, D.C.
EPA 540R-98-050.
United States Environmental Protection Agency (USEPA). 1999b. National Recommended
Water Quality Criteria - Correction. Office of Water, EPA-822-Z-99-001. April.
United States Environmental Protection Agency (USEPA). 1998. Notes from Whitewood Creek
Five Year Review Inspection Interviews. Michael H. McCeney, USEPA Region VIII. Denver,
Colorado. March 13.
United States Environmental Protection Agency (USEPA). 1997a. EPA Comments to the
Whitewood Creek Five Year Review Data Report Dated January 31, 1997. USEPA Region VIII.
Denver Colorado. September 18.
United States Environmental Protection Agency (USEPA). 1997b. Ecological Risk Assessment
Guidance for Superfund: Process for Designing and Conducting Ecological Risk Assessments.
Interim Final. U.S. Environmental protection Agency, Environmental Response Team (Edison,
NJ). June 5, 1997.
11 - 13
-------
United States Environmental Protection Agency (USEPA). 1996. Whitewood Creek Five Year
Review Start and Completion Dates. Michael McCeney, RPM, USEPA, Region VIII. Denver,
Colorado. December 26.
United States Environmental Protection Agency (USEPA). 1995. Whitewood Creek Superfund
Site Certification of Completion of Remedial Action. William P. Yellowtail, Regional
Administrator. USEPA Region VIII. Denver, Colorado. February, 13.
United States Environmental Protection Agency (USEPA). 1994. Site Closeout Report:
Whitewood Creek Superfund Site Butte, Meade and Lawrence Counties, South Dakota.
USEPA, Region VIII. Denver, Colorado. September 24.
United States Environmental Protection Agency (USEPA). 1993. Remedial Action Report:
Whitewood Creek Superfund Site Butte, Meade and Lawrence Counties, South Dakota.
USEPA, Region VIII. Denver, Colorado. March 31.
United States Environmental Protection Agency (USEPA). 1992. Framework for Ecological
Risk Assessment. Risk Assessment Forum. EPA/630/R-92/001. February 1992.
U.S. Environmental Protection Agency. 1991. Role of the Baseline Risk Assessment in
Superfund Remedy Selection Decisions. OSWER Directive 9355.0-30. April.
United States Environmental Protection Agency (USEPA). 1990. Superfund Record of
Decision: Whitewood Creek, South Dakota. Office of Emergency and Remedial Response.
EPA/ROD/R08-90/028, March, 1990.
United States Environmental Protection Agency (USEPA). 1989a. Endangerment Assessment for
the Whitewood Creek Superfund Site, Southwestern South Dakota. Volumes I and II. Office of
Health and Environmental Assessment, Office of Research and Development, Washington, D.C.,
OHEA-E-269. Final Draft. March 1989.
United States Environmental Protection Agency (USEPA). 1989b. Risk Assessment Guidance
for Superfund Volume II Environmental Evaluation Manual. Interim Final. Office of Emergency
and Remedial Response. Washington, D.C. EPA/540/1-89/001. March 1989.
11 - 14
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U.S. Geological Survey (USGS). 1989. Composition, Distribution, and Hydrologic Effects of
Contaminated Sediments Resulting from the Discharge of Gold Milling Wastes to Whitewood
Creek at Lead and Deadwood, South Dakota. Edited by Kimball Goddard. USGS. Water
Resources Investigation Report 87-4051.
United States Environmental Protection Agency (USEPA). 1988. Guidance for Conducting
Remedial Investigations and Feasibility Studies Under CERCLA. EPA/540/G-89/004. OSWER
Directive 9355.3-01. Office of Emergency and Remedial Response, Washington DC. October.
U.S. Geological Survey (USGS). 1985. Composition, Distribution and Hydrologic Effects of
Mine and Mill Wastes Discharged to Whitewood Creek at Lead/Deadwood, South Dakota.
Draft. Water Resources Investigation Report 85.
Whitewood Development Corporation (WDC). 1991. Whitewood Creek Superfund Site
Sampling and Analysis Plan for Residential Remediation and Surface Water Monitoring SAP.
Whitewood Development Corporation (WDC). 1998. Construction Completion Report for
Holsclaw Site. August, 1998.
Whitewood Development Corporation (WDC). 1994a. Whitewood Creek Institutional Controls
Completion Report. Whitewood Development Corporation. Lead, South Dakota. July 27, 1994.
Whitewood Development Corporation (WDC). 1994b. Whitewood Creek Superfund Site Post
Closure Operations, Maintenance, and Reporting Plan Volume I. Whitewood Development
Corporation. Lead, South Dakota. July 27.
11 - 15
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TABLES
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Table 2-1
Chronology of Events at the Whitewood Creek Superfund Site
I.M.M
DATE
ACTIVITY
1960
Quantified solids and cyanide loading to Whitewood Creek.
1965
South Dakota (SD) Dept of Game, Fish and Parks determined
aquatic bottom organisms not present in Whitewood Creek.
Initial Discovery
of Problem or
Contamination
1970-1971
May 1975 - July
1978
The USEPA and the US Food and Drug Administration
characterized tailing discharge to Whitewood Creek and the
extent of resultant pollution. A University of SD study focused
on the environmental hazard of mercury contamination.
SD Geological Survey and Water Resources Division investigated
the presence of arsenic in surface water and groundwater along
Whitewood Creek, the Belle Fourche River and portions of the
Cheyenne River. Arsenic concentrations were found ranging
from 2.5 to 1,530 ug/L in groundwater.
NPL listing
September 1981
September 1983
Interim listing.
Official listing.
Remedial
Investigation and
Feasibility Study
July 1989
December 1989
Endangerment Assessment (EA) released by USEPA and Jacobs
Engineering).
Feasibility Study (FS) completed by ICF Technology Inc.
ROD Signature
March 30, 1990
Record of Decision (ROD) completed.
ROD Amendments
orESDs
June 1991
Explanation of Significant Difference (ESD) signed modifying
the remedy to dispose of contaminated soils on-site.
December 1988
Administrative Order on Consent signed by USEPA and
Homestake requiring Homestake to conduct an FS for the site.
Enforcement
Documents
August 1990
Consent Decree signed by USEPA and Homestake to implement
the ROD through remedial design and remedial action at the site.
Case No. 90-5101 was lodged inU.S. District Court of South
Dakota on October 10, 1990 and entered by the Court on April 4,
1991).
Table 2-l.wpd
Page 1 of 3
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Table 2-1
Chronology of Events at the Whitewood Creek Superfund Site
I.M.M
DATE
ACTIVITY
1981
USEPA sent notice letter to Homestake notifying them of
potential liability at Whitewood Creek and requesting
information about their activities.
1982
USEPA, State of SD and Homestake began negotiations for
Homestake to perform necessary studies.
Enforcement
Action
August 11, 1982
USEPA, the State of SD and Homestake completed negotiations
and signed a memorandum of understanding among the three
parties to conduct a study of the Whitewood Creek area.
September 1988
Special Notice Letter sent to Homestake and Goldstake
Explorations, Inc. informing them that both companies were
Primary Responsible Parties (PRPs) for cleanup of the site.
Notice gave both parties the opportunity to conduct the feasibility
study. Goldstake elected not to participate in the FS studies.
Remedial Design
Start
August 1990
June 14, 1991
Homestake conducted sampling to identify and characterize soil
contamination at 32 residences, 27 of which were identified for
remediation.
USEPA approval to proceed with the Institutional Controls
Component to the remedy.
Actual Remedial
Action Start
September 1991
May 1992
Began a pilot remediation project of one residence/site.
Began remediation of 15 remaining residences/sites.
Construction Dates
(start to finish)
September-October
1991
Pilot remediation project.
September 30, 1991-
September 30, 1992
Disposal Site construction and completion.
May-September
1992
July-September 1992
1993 - 1994
November 18, 1993
Remediation of remaining 15 residences/sites.
Construction and removal of the Temporary Stream Crossing.
Institutional Controls implemented at the site.
Quarterly Operations and Maintenance (O&M) Reports
Commenced.
May 1993
Surface Water Monitoring Program initiated.
Table 2-l.wpd
Page 2 of 3
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Table 2-1
Chronology of Events at the Whitewood Creek Superfund Site
I.M.M
DATE
ACTIVITY
Construction
Completion Date
December 21, 1992
July 1994
July 1998
Construction completion date for residential remediation.
Institutional Controls Completion Report.
Construction completion of Holsclaw property re-remediation.
Final Close Out
Report
September 26, 1994
Documents that ROD was fully implemented at the Whitewood
Creek Site.
NPL Delisting
August 1996
Whitewood Creek Site delisted from NPL.
Table 2-l.wpd
Page 3 of 3
-------
Table 4-1
Summary of Residential Remediation Activities
Residence
General
Construction Start
Date
Construction
Completion Date
Type and Quantity of Materials
Removed
ALA
August 26, 1992
September 2, 1992
Sod and Soil
120 Cubic Yards
ALAN
May 26, 1992
June 19, 1992
Sod and Soil
786 Cubic Yards
BALO-LOWER
June 29, 1992
July 10, 1992
Sod and Soil
0 Cubic Yards
BALO-UPPER
June 9, 1992
June 11, 1992
Sod and Soil
130 Cubic Yards
BERGER
August 11, 1992
September 3, 1992
Sod and Soil
540 Cubic Yards
HOLSCLAW
July 28, 1992
August 27, 1992
Sod and Soil
290 Cubic Yards
KYMALA
September 14, 1992
September 16, 1992
Soil and Gravel
0 Cubic Yards
MARRS
September 30, 1991
October 15, 1991
Sod, Soil, and
Gravel
Tree Stumps
368 Cubic Yards
NELSON
June 11, 1992
June 26, 1992
Sod and Soil
372 Cubic Yards
SHUCK
July 8, 1992
September 1, 1992
Sod and Soil
260 Cubic Yards
SHUCK NORTH
December 22, 1992
July 1, 1992
Sod and Soil
420 Cubic Yards
TIPPEY
June 29, 1992
June 29, 1992
Gravel and Soil
50 Cubic Yards
WENNEBERG
June 24, 1992
July 10, 1992
Sod and Soil
350 Cubic Yards
WESTBERG
May 11, 1992
May 21, 1992
Sod and Soil
750 Cubic Yards
Irrigation Pipe
1,287 Lineal Feet
Trees
4 trees
WESTBERG
May 11, 1992
May 21, 1992
Sod and Soil
82 Cubic Yards
WILLSON
June 26, 1992
June 26, 1992
Gravel and Soil
50 Cubic Yards
Source: FMG (1992)
Table 4-l.wpd
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Table 4-2
Review of Residential Building Activities Within the Whitewood Creek Superfund Site
Quarter
Review Date
Summary of Findings
3rd Quarter 1993
Summer/Fall 1993
Crowsers recently purchased property and established a seasonally
occupied mobile home. The purchase occurred between the time of
residential remediation and passage of land use control ordinances.
The owners were aware of the Site at the time of purchase. While the
mobile home is currently unoccupied, a family member occupies the
home during the summer months. Soil samples were taken and
samples show that a portion of the yard area is on tailings impacted
soils. The landowner agreed to complete the remediation in
accordance with the sampling and arsenic reducing activities outlined
in the county handbook.
4 th Quarter 1993
October to December 1993
No new residential building activity occurred.
1st Quarter 1994
January to March 1994
No new residential building activity occurred.
2nd Quarterl 994
April to June 1994
No new residential building activity occurred.
3rd Quarter 1994
July to September 1994
No new residential building activity observed.
4 th Quarter 1994
October to December 1994
No new residential building activity observed.
1st Quarter 1995
January to March 1995
No new residential building activity observed.
2nd Quarter 1995
April to June 1995
No new residential building activity observed.
3rd Quarter 1995
July to September 1995
No new residential building activity occurred.
4 th Quarter 1995
October to December 1995
No new residential building activity occurred.
1st Quarter 1996
January to March 1996
No new residential building activity occurred.
2nd Quarter 1996
April to June 1996
No new residential building activity occurred.
3rd Quarter 1996
July to September 1996
No new residential building activity identified or observed.
4th Quarter 1996
October to December 1996
No new residential building activity identified or observed.
1st Quarter 1997
January to March 1997
No new residential building activity was identified or observed. The
landowner of the Berger property is contemplating building a new
residence. The landowner is coordinating activity with the local
planning authorities in Meade County.
2nd Quarter 1997
April to June 1997
No new residential building activity was identified or observed, other
than at the Berger property.
3rd Quarter 1997
July to September 1997
No known residential building activities occurred within the Site
during the reporting period.
4th Quarter 1997
October to December 1997
No known residential building activities occurred within the Site
during the reporting period.
1st Quarter 1998
January to March 1998
No known residential building activities occurred within the Site
during the reporting period.
Table 4-2 - Review of residential development activities.wpd
Page 1 of 2
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Table 4-2
Review of Residential Building Activities Within the Whitewood Creek Superfund Site
Quarter
Review Date
Summary of Findings
2nd Quarter 1998
April to June 1998
No known residential building activities occurred within the Site
during the reporting period.
3rd Quarter 1998
July to September 1998
No known residential building activities occurred within the Site
during the reporting period.
4 th Quarter 1998
October to December 1998
No known residential building activities occurred within the Site
during the reporting period.
1st Quarter 1999
January to March 1999
No known residential building activities occurred within the Site
during the reporting period.
2nd Quarter 1999
April to June 1999
NA
3rd Quarter 1999
July to September 1999
No known residential building activities occurred within the Site
during the reporting period.
4 th Quarter 1999
October to December 1999
No known residential building activities occurred within the Site
during the reporting period.
1 st Quarter 2000
January to March 2000
No known residential building activities occurred within the Site
during the reporting period.
2nd Quarter 2000
April to June 2000
NA
3rd Quarter 2000
July to September 2000
No known residential building activities occurred within the Site
during the reporting period.
4th Quarter 2000
October to December 2000
No known residential building activities occurred within the Site
during the reporting period.
1st Quarter 2001
January to March 2001
No known residential building activities occurred within the Site
during the reporting period.
2nd Quarter 2001
April to June 2001
No known residential building activities occurred within the Site
during the reporting period.
3rd Quarter 2001
July to September 2001
No known residential building activities occurred within the Site
during the reporting period.
4th Quarter 2001
October to December 2001
No known residential building activities occurred within the Site
during the reporting period.
Source: HMC (1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002)
Table 4-2 - Review of residential development activities.wpd
Page 2 of 2
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Table 4-3
Summary of Observations and Remedial Actions Taken During
Annual Inspections of the Disposal Site
Inspection Date
Comments
Remedial Actions Taken
December 3, 1993
All areas of site appeared stable, no work
necessary.
None.
June 3, 1994
All areas of site appeared stable, no work
necessary.
None.
May 12, 1995
All areas of site appeared stable; no work
deemed necessary.
None.
May 13, 1996
All areas of the site appeared stable.
Minor fence repairs were completed
July 15, 1996
No items of concern requiring immediate
response noted. Good vegetative
establishment observed on disposal site-
no problems noted.
Future inspection will need to observe
whether any new creek bank cutting occurs
next to the monitoring well site.
September 1, 1997
No problems identified during visit to
the disposal site.
None.
July-September 1998
Inspected only to evaluate unauthorized
rubble piles placed on the site to develop
a appropriate disposal or removal plan.
Removal of the unauthorized rubble
anticipated to be addressed during the 4th
quarter of 1998.
October-December 1998
None.
Unauthorized rubble was placed in the
disposal facility. Rip-rap was replaced and
the disturbance seeded. Some scrap
materials were removed from the Site and
disposed of at a local landfill.
April-June 1999
Visual inspection conducted; incidental
to field review and assessment of the
Whitewood Creek channel adjacent to
the disposal site area; no problems or
issues related to the disposal cell were
noted.
None.
October-December 1999
No formal inspection conducted.
However, a small bank stabilization
project on a short section of Whitewood
Creek near the disposal site during the
report period was conducted.
Observations of the disposal site at that
time indicated no issues or concerns
related to the disposal cell.
None.
June 1, 2000
No issues identified. Vegetative cover
on cell is stable, no erosion is evident;
rip-rap protective material on cell face
and up gradient along creek bank show
no need of maintenance or repair.
Vegetative cover on a portion of the
ground inside the fence enclosure
Additional organic material, hay will be
tilled into soils near the bank stabilization
project to increase opportunity for
vegetative establishment.
Table 4-3 - disposal site O&M observations.wpd
Page 1 of 2
-------
Table 4-3
Summary of Observations and Remedial Actions Taken During
Annual Inspections of the Disposal Site
Inspection Date
Comments
Remedial Actions Taken
surrounding soil disposal cell requires
additional work.
October 4, 2000
Disposal cell and
upgradient/downgradient protective rip-
rap areas inspected. Cell and rip-rap
observed to be in stable condition. No
erosional or vegetative stability issues
were noted. No other issues identified
requiring further investigation or follow
up.
None.
May 2001
Site inspection was not conducted during
the 2nd quarter. Reopening and
subsequent reclosure, topsoiling, seeding
and rip-rap armoring of the disposal cell
face was completed during the period in
relation to disposal of soil samples
previously collected at various locations
within the site.
None.
Source: HMC (1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001)
Table 4-3 - disposal site O&M observations.wpd
Page 2 of 2
-------
Table 4-4
Summary of Quarterly Reports Submitted During Site
Operation and Maintenance Activities
Quarter
Report Number
Report Date
1
3rd-1993
November 18, 1993
2
4th-1994
January 31, 1994
3
1st-1994
April 29, 1994
4
2nd-1994
July 31, 1994
5
3rd-1994
October 31, 1994
6
4th-1994
January 31, 1995
7
1st-1995
April 30, 1995
8
2nd-1995
July 31, 1995
9
3rd-1995
October 31, 1995
10
4th-1995
January 31, 1996
11
1st-1996
April 30, 1996
12
2nd-1996
July 31, 1996
13
3rd-1996
October 31, 1996
14
4th-1996
January 31, 1997
15
1st-1997
April 30, 1997
16
2nd-1997
July 29, 1997
17
3rd-1997
October 30, 1997
18
4th-1997
January 20, 1998
19
1st-1998
April 30, 1998
20
2nd-1998
July 30, 1998
21
3rd-1998
October 27, 1998
22
4th-1998
January 13, 1999
23
1st-1999
April 28, 1999
24
2nd-1999
July 28, 1999
25
3rd-1999
October 19, 1999
26
4th-1999
January 25, 2000
27
lst-2000
April 21, 2000
28
2nd-2000
July 25, 2000
Table 4-4 Quarterly Reports.wpd
Page 1 of 2
-------
Table 4-4
Summary of Quarterly Reports Submitted During Site
Operation and Maintenance Activities
Quarter
Report Number
Report Date
29
3rd-2000
October 30, 2000
30
4th-2000
January 31, 2001
31
lst-2001
April 24, 2001
32
2nd-2001
July 30, 2001
33
3rd-2001
October 29, 2001
34
4th-2001
January 31, 2002
Source: HMC (1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002)
Table 4-4 Quarterly Reports.wpd
Page 2 of 2
-------
Table 5-1
Applicable or Relevant and Appropriate Requirements (ARARs) for Whitewood Creek Superfund Site
ARAR
Citation
Description
CHEMICAL-SPECIFIC
National Primary Drinking Water Standards'"
40CFR141
Maximum Contaminant Levels (MCLs) for community water systems, relevant and appropriate to downgradient
alluvial groundwaters of Whitewood Creek as a potential future water supply source.
National Water Quality Criteria**
40CFR131
Establishes criteria for the protection of aquatic life and the protection of human health through consumption of
fish and water. Not applicable because they are not enforceable standards, however relevant and appropriate for
protection of human health from fish consumption.
National Ambient Air Quality Standards
40 CFR 50
Standards for ambient air quality to protect human health and welfare. Applicable, as standards may not be
attained during brief times during remedy implementation.
RCRA MCLs*
40 CFR 264.94
Relevant and appropriate; but waived for same reason as MCLs above
South Dakota Groundwater Quality Standards*
ARSD 74:03:15
Establishes maximum concentrations for groundwater to protect all ground waters of the state. Standards
applicable to downgradient alluvial ground water as a potential future drinking water source.
South Dakota Drinking Water Standards*
ARSD 74:04:05
Establishes MCLs for community drinking water supplies, relevant and appropriate to downgradient alluvial
groundwaters of Whitewood Creek as a potential future drinking water source.
Surface Water Quality Standards**
ARSD 74:03:02
Establishes water quality standards for Whitewood Creek for protection of human health from fish consumption
and for the protection of aquatic life
Ambient Air Quality Standards
ARSD 74:26:02:04
ARSD 74:26:02:35
Establishes ambient air quality standards for particulate matter. These standards are applicable, as they may not
be attained during brief periods during the implementation of the remedy.
LOCATION-SPECIFIC
Archaeological and Historic Preservation Act
40 CFR 6.301(c)
Establishes procedures to preserve historical and archaeological data which might be destroyed through alteration
of terrain that might be applicable to remedial actions (removal of tailings). Determined during remedial design
to be not applicable or relevant and appropriate based upon field investigations that did not identify sites of
archeological or historical significance that would be affected by the remedial actions.
Historic Sites, Buildings and Antiquities Act
40 CFR 6.301 (a)
36 CFR 62.6(d)
Requires considering the existence and location of landmarks on the national registry of natural landmarks to
avoid undesirable impacts on landmarks. Applicability of this requirement was believed to not be applicable or
relevant and appropriate in that no eligible properties were identified during the survey.
National Historic Preservation Act
40 CFR 6.301(b)
36 CFR 800
36 CFR 63
Coordination with other environmental review and consultation requirements. Requires effects on any district,
site, building, structure or object that is included or eligible for inclusion in the national register of historic
places. Was determined to be not applicable or relevant and appropriate during the remedial design, in that no
eligible properties were identified during a 1991 survey of cultural resources.
Fish and Wildlife Coordination Act
40 CFR 6.302(g)
Requires consultation with Fish and Wildlife Service for the modification of any stream or other water body and
adequate provision for protection of fish and wildlife resources. Determined to be applicable to modification of
Whitewood Creek.
Endangered Species Act
40 CFR Section 6.302(h)
Requires protection of any threatened or endangered species and their critical habitat. Requirement determined
to be not applicable or relevant and appropriate in that no endangered species habitat is believed to be affected by
the remedy. No known threatened or endangered species area ffected by the project as determined by the 1990
Baseline Wildlife Survey of Whitewood Creek
Floodplain Management
40 CFR Part 6, Appendix A,
Executive Order 11,988
Requires evaluation of potential effects of actions taken in floodplain to avoid adverse impacts associated with
direct and indirect development of the floodplain. Determined during remedial design activities to be applicable
to disposal of excavated soils and the crossing of Whitewood Creek.
Protection of Wetlands
40 CFR Part 6, Appendix A,
Executive Order 11,990
Requires Avoidance of adverse impact associated with the destruction or loss of wetlands. Determined to be
applicable because of modifications to Whitewood Creek for the Berger Site crossing. No wetlands were
identified in the area in which the residential soils are to be disposed.
Dredge or Fill Requirements
40 CFR Parts 230,231, and
33; 40 CFR Part 323
May be applicable depending upon on-site disposal location, to be determined during remedial design
DOT Hazardous Material Transportation regulatioi
49 CFR Parts 107,171,177
Requirements on the transportation of hazardous materials, potentially relevant and appropriate to the transport of
contaminated medial to the on-site disposal location. However, determined not applicable or relevant and
appropriate as material to be transported is not considered a DOT hazardous material.
WWC ARAR evaluation v2.xls: Orig ARARs Page 1 of 2
-------
Table 5-1
Applicable or Relevant and Appropriate Requirements (ARARs) for Whitewood Creek Superfund Site
ARAR | Citation | Description
\< 1 lo\ SIM < M M
Occupational Safely and Health Act
29U.S.C. Sections 651-678
subject to these regulations. To be determined during remedial design.
Water Right Rules
ARSD 74:02
Regulations governing the use of groundwater, including prohibiting installation of water supply wells within the
site.
Solid Waste Disposal Act
40 CFR 241
Regulations regarding the disposal of solid wastes on land. While mining wastes are exempted, the siting and
closure criteria are relevant and appropriate to site remedial actions.
Solid Waste Disposal Act
40 CFR 257.3
Criteria for Classification of Solid Waste Disposal Facilities and Practices. Establishes criteria to assess affects
of disposal practices on health and environment for purposes of identifying prohibited "open dumps".
Applicable to the disposal of excavated soil.
Solid Waste Disposal Act
40 CFR 264.111-112
General Standards for Ownder and Operators of Hazardous Waste Treatment, Storage, and Disposal Areas.
Establishes requirement for closure and post-closure plan and standards of performance protective of health and
environment. Determined to be relevant and appropriate for disposal activities.
Solid Waste Disposal Act
40 CFR 264
(264.251 and 264.258)
General Standards for Owner and Operators of Hazardous Waste Treatment, Storage and Disposal Areas.
Establishes design and operating requirements for waste piles to protect surface-and ground-water quality and for
closure and post-closure care. Determined to be relevant and appropriate for disposal activities.
Solid Waste Disposal Act
40 CFR 264
(264.301 and 264.310)
General Standards for Owner and Operators of Hazardous Waste Treatment, Storage and Disposal Areas.
Establishes design and operating requirements for landfills to protect surface and ground-water quality and for
closure and post-closure care. Determined to be relevant and appropriate for disposal activities.
Surface Mining Control and Reclamation Act
30 CFR 816
(816.111)
Performance standards for surface mining. Establishes general requirements for revegetation in terms of diverse,
effective, and permanent. Determined to be relevant and appropriate
Surface Mining Control and Reclamation Act
30 CFR 784
(784.13)
Permit Application Requirements for Underground Mines. Establishes information requirements for surface
disturbances of underground mines. Determined to be relevant and appropriate.
Clean Water Act
40 CFR 230
40 CFR 231
Dredge and Fill Requirements (404 requirements). Establishes guidelines for fill projects including provisions to
protect suface-water quality, aquatic life, and critical habitat of threatened or endangered species. Determined to
be applicable to the crossing of Whitewood Creek. No known threatened or endangered species are affected by
the project, nor were any wetlands identified in the area in which the residential soils are to be disposed.
Solid Waste Disposal Act
40 CFR Part 264 264.251
( c), (d), (f)
Regulations for waste piles, may be relevant and appropriate to provision on contouring and dust control at the
site.
Solid Waste Regulation
ARSD 74:27:03:08
Requires facilities located in a floodplain to be adequately protected against a 100-year flood
Solid Waste Regulation
ARSD 74:27:09:02
Requires design and construction plans and specifications be prepared and certified by a qualified professional
engineer registered in the state of South Dakota.
Solid Waste Regulation
ARSD 74:27:12:09
Establishes requirements for the control of public access. Applicable to the disposal of excavated soils.
Solid Waste Regulation
ARSD 74:27:12:16
Requires surface water to be controlled by diverting drainage around or away from the filled site.
Solid Waste Regulation
ARSD 74:27:13:23
Requires no person excavate, disrupt or remove any deposited material from an active or discontinued landfill.
Applicable to excavated soil disposal.
Solid Waste Regulation
ARSD 74:27:15:04
Requires a written closure plan be prepared describing the steps necessary to close a facility. Applicable to
disposal of excavated soil.
Sources:
USEPA, 1990. Record of Decision, Whitewood Creek Superfund Site
WDC, 1991. On-site Disposal Plan for Contaminated Soils at Whitewood Creek Superfund Site
WDC, 1992. ARAR Report for Whitewood Creek Superfund Site
Notes
*ARAR waived because of the technical impracticability of meeting the requirements
**ARAR waived due to technical impracticability, as water entering the site does not meet these criteria
VWVC ARAR evaluation v2.xls: Orig ARARs
Page 2 of 2
-------
Table 5-2
Changes in Chemical-Specific ARARs
GROUND WATER ARARs
SURFACE WATER ARARs
AMBIENT AIR ARARs
AWQC (ug/L)
SD WQS (ug/L)
NAAQS
SDAAQS
Contaminant
NPDWS
(mg/L)
Source
SD DWS
(mg/L)
Source
SD WQS
(mg/L)
Source
Fish
Consumption
Freshwater Acute
Total Dissolved
Freshwater Chronic
Total Dissolved
Source
Fish
Consumption
Freshwater Acute
Total Dissolved
Freshwater Chronic
Total Dissolved
Source
PM1024 iu
(ug/m3) (ug/m3)
Source
PM1024 iu
(ug/m3) (ug/m3)
Source
Antimony
Previous
Current
NA
0.006
40 CFR 141
40 CFR 141
1990
2001
NA
0.006
ARSD 74:04:05; 1988
ARSD 74:04:05:03; 2001
NA
NA
ARSD 74:03:15; 1987
ARSD 74:54:01:04; 2001
45,000
4,300
9,000e
NA
9,000
NA
l,600e
NA
9,000
NA
EPA/440/5-86/001; 1986
EPA 822-Z-99-001; April 1999b
45,000
4,300
9,000e
NA
9,000
NA
l,600e
NA
9,000
NA
ARSD 74:03:02; 1990
ARSD 74:51:01:55; 2001
"
Arsenic
Previous
Current
0.05
0.01
40 CFR 141
66 FR 20580
1990
2001
0.05
0.05
ARSD 74:04:05; 1988
ARSD 74:04:05:03; 2001
0.05
0.05
ARSD 74:03:15; 1987
ARSD 74:54:01:04; 2001
0.0175
0.14b
360f
340
360
340
190f
150
190
150
EPA/440/5-86/001; 1986
EPA 822-Z-99-001; April 1999b
0.0175
0.14b
360f
360
360
360
190f
190
190
190
ARSD 74:03:02; 1990
ARSD 74:51:01:55; 2001
"
Cadmium
Previous
Current
0.01
0.005
40 CFR 141
40 CFR 141
1990
2001
0.01
0.005
ARSD 74:04:05; 1988
ARSD 74:04:05:03; 2001
0.01
0.005
ARSD 74:03:15; 1987
ARSD 74:54:01:04; 2001
NA
NA
3.9C
2.r
3.7C
2.0C
l.lc
0.3C
1.0C
0.2C
EPA/440/5-86/001; 1986
EPA-822-R-01-001; 2001
NA
NA
3.9C
3.9C
3.7C
3.7C
l.lc
i.r
1.0C
1.0C
ARSD 74:03:02; 1990
ARSD 74:51:01:55; 2001
"
Chromium (VI)
Previous
Current
0.05 a
0.1 a
40 CFR 141
40 CFR 141
1990
2001
0.05a
0.1a
ARSD 74:04:05; 1988
ARSD 74:04:05:03; 2001
0.05a
0.1a
ARSD 74:03:15; 1987
ARSD 74:54:01:04; 2001
NA
NA
16
16.3
15.7
16
11
11.4
10.6
11
EPA/440/5-86/001; 1986
EPA 822-Z-99-001; April 1999b
NA
NA
16
15.3
15.7
15
ii
10.4
10.6
10
ARSD 74:03:02; 1990
ARSD 74:51:01:55; 2001
Chromium (III)
Previous
Current
0.05 a
0.1a
40 CFR 141
40 CFR 141
1990
2001
0.05 a
0.1a
ARSD 74:04:05; 1988
ARSD 74:04:05:03; 2001
0.05a
0.1a
ARSD 74:03:15; 1987
ARSD 74:54:01:04; 2001
3,433,000
NA
1700c
1803c
537c
570c
210c
86c
180.6C
74c
EPA/440/5-86/001; 1986
EPA 822-Z-99-001; April 1999b
3,433,000
NA
1700c
1740c
537c
550c
210c
207c
180.6C
180c
ARSD 74:03:02; 1990
ARSD 74:51:01:55; 2001
"
Copper
Previous
Current
NA
1.3*
40 CFR 141
40 CFR 141
1990
2001
NA
NA
ARSD 74:04:05; 1988
ARSD 74:04:05:03; 2001
1.3
1.3
ARSD 74:03:15; 1987
ARSD 74:54:01:04; 2001
NA
1300
18c
14c
17.3C
13.4C
12c
9.3C
11.5°
9.0C
EPA/440/5-86/001; 1986
EPA 822-Z-99-001; April 1999b
NA
NA
18c
17.7C
17.3C
17c
12c
11.5C
11.5C
llc
ARSD 74:03:02; 1990
ARSD 74:51:01:55; 2001
"
Lead
Previous
0.05
40 CFR 141
1990
0.05
ARSD 74:04:05; 1988
0.02
ARSD 74:03:15; 1987
NA
82c
65c
3.2C
2.5C
EPA/440/5-86/001; 1986
NA
82c
65c
3.2C
2.5C
ARSD 74:03:02; 1990
-
Current
0.015*
40 CFR 141
2001
NA
ARSD 74:04:05:03; 2001
0.015
ARSD 74:54:01:04; 2001
NA
81.6C
65c
3.2C
2.5C
EPA 822-Z-99-001; April 1999b
NA
81.6C
65c
3.2C
2.5C
ARSD 74:51:01:55; 2001
-
--
Mercury
Previous
Current
0.002
0.002
40 CFR 141
40 CFR 141
1990
2001
0.002
0.002
ARSD 74:04:05; 1988
ARSD 74:04:05:03; 2001
0.002
0.002
ARSD 74:03:15; 1987
ARSD 74:54:01:04; 2001
0.146
1.7
2.4
1.7°
2
1.4
0.012
0.91
0.01
0.77
EPA/440/5-86/001; 1986
EPA 822-Z-99-001; April 1999b
0.146
0.15
2.4
2.5
2
2.1
0.012
0.012
0.01
0.01
ARSD 74:03:02; 1990
ARSD 74:51:01:55; 2001
Nickel
Previous
Current
NA
NA
40 CFR 141
40 CFR 141
1990
2001
NA
0.1
ARSD 74:04:05; 1988
ARSD 74:04:05:03; 2001
NA
NA
ARSD 74:03:15; 1987
ARSD 74:54:01:04; 2001
100
4600
1400c
469c
1397c
468c
160c
52.2C
159.5C
52c
EPA/440/5-86/001; 1986
EPA 822-Z-99-001; April 1999b
100
4600
1400c
471c
1397c
470c
160c
52.2C
159.5C
52c
ARSD 74:03:02; 1990
ARSD 74:51:01:55; 2001
"
Selenium
Previous
Current
0.01
0.05
40 CFR 141
40 CFR 141
1990
2001
0.01
0.05
ARSD 74:04:05; 1988
ARSD 74:04:05:03; 2001
0.01
0.05
ARSD 74:03:15; 1987
ARSD 74:54:01:04; 2001
NA
ll,000e
260
NA
240
NA
35
5
32
4.6
EPA/440/5-86/001; 1986
EPA 822-Z-99-001; April 1999b
NA
NA
260
22
240
20
35
5.4
32
5
ARSD 74:03:02; 1990
ARSD 74:51:01:55; 2001
"
Silver
Previous
0.05
40 CFR 141
1990
0.05
ARSD 74:04:05; 1988
0.05
ARSD 74:03:15; 1987
NA
4.r
3.5C
0.12
0.12
EPA/440/5-86/001; 1986
NA
4.r
3.5C
0.12
0.12
ARSD 74:03:02; 1990
-
Current
NA
40 CFR 141
2001
NA
ARSD 74:04:05:03; 2001
0.05
ARSD 74:54:01:04; 2001
NA
4.r
3.4C
NA
NA
EPA 822-Z-99-001; April 1999b
NA
4.r
3.4C
NA
NA
ARSD 74:51:01:55; 2001
--
--
Zinc
Previous
NA
40 CFR 141
1990
NA
ARSD 74:04:05; 1988
NA
ARSD 74:03:15; 1987
NA
120c
117C
110c
108c
EPA/440/5-86/001; 1986
NA
120c
117C
110c
108c
ARSD 74:03:02; 1990
-
Current
NA
40 CFR 141
2001
NA
ARSD 74:04:05:03; 2001
NA
ARSD 74:54:01:04; 2001
69,000
120c
117C
120c
118c
EPA 822-Z-99-001; April 1999b
NA
112c
110c
ior
100c
ARSD 74:51:01:55; 2001
-
--
Cyanide
Previous
Current
NA
0.2d
40 CFR 141
40 CFR 141
1990
2001
NA
0.2
ARSD 74:04:05; 1988
ARSD 74:04:05:03; 2001
0.2
0.75
ARSD 74:03:15; 1987
ARSD 74:54:01:04; 2001
NA
220,000
22
22d
22
22d
5.2
5.2d
5.2
5.2d
EPA/440/5-86/001; 1986
EPA 822-Z-99-001; April 1999b
NA
220,000d
22
22d
22
22d
5.2
5.2d
5.2
5.2d
ARSD 74:03:02; 1990
ARSD 74:51:01:55; 2001
"
Particulates
Previous
150 [1] 50 [2]
40 CFR 50; 1990
150 [1] 60 [2]
ARSD 74:26:02:04; 1990
(PM10)
Current
-
-
-
-
-
-
-
-
-
-
150 [1] 50 [2]
40 CFR 50; 2001
150 [1] 50 [2]
ARSD 74:36:02; 2001
Notes
* Action level regulation for treatment techniques; if exceeded in more than 10% of tap water samples water systems are triggered into taking treatment steps
[a] Total chromium
[b] = Human health criteria based on 1E-06 carcingenicity risk
[c]=Hardness dependant, based upon 100 mg/1 CaC03
[d]=Criteria expressed as free cyanide as CN/L
[e]=Insuffrcient data to develop critieria; value presented is the LOEL
[f]=Trivalent arsenic
[g]=Criteria based on total recoverable fraction
[h]=Weak acid dissociable cyanide
[i] = Max 24 hour concentration
[j] = Annual geometric mean
NPDWS=National Primary Drinking Water Standards
SD DWS= South Dakota Drinking Water Standards
AWQC= National Recommended Ambient Water Quality Criteria
SD WQC= South Dakota Water Quality Criteria
NA=Criteria Not Available
CFR=Code of Federal Regulations
ARSD=Administrative Record of South Dakota
FR=Federal Register
EPA = United States Environmental Protection Agency
VWVC ARAR evaluation v2.xls: Chem Specific
7/10/2002
-------
Table 5-3
Summary of the Changes in Stringency of Site Chemical-Specific ARARs
Regulation
More Stringent
Less Stringent
Unchanged
Antimony (federal and state)
Chromium (federal and state)
Arsenic (state)
GROUND
Arsenic (federal)
Lead (state)
Copper (state)
WATER
Cadmium (federal and state)
Selenium (federal and state)
Mercury (federal and state)
Cyanide (federal and state)
Lead (state)
Nickel (federal)
Drinking Water
Copper* (federal)
Silver (federal and state)
Zinc (federal and state)
Standards
Lead* (federal)
Nickel (state)
GROUND
Cadmium
Chromium
Antimony
WATER
Lead
Selenium
Arsenic
Cyanide
Copper
South Dakota
Mercury
Groudwater
Nickel
Quality
Silver
Standards
Zinc
SURFACE
Antimony (federal and state)
Arsenic (federal and state)
Cadmium (federal and state)
WATER
Copper (federal)
Chromium III (federal and
Chromium VI (federal and state)
Selenium (federal)
state)
Copper (state)
Ambient Water
Zinc (federal)
Mercury (federal and state)
Lead (federal and state)
Quality Criteria
Cyanide (federal and state)
Nickel (federal and state)
Selenium (state)
(fish '
Silver (federal and state)
consumption)
Zinc (state)
SURFACE
Arsenic (federal)
Antimony (federal and state)
Arsenic (state)
WATER
Chromium VI (state)
Cadmium (federal)
Cadmium (state)
Copper (federal and state)
Chromium III (federal and
Chromium VI (fed)
Ambient Water
Mercury (federal)
state)
Lead (federal and state)
Quality Criteria
Nickel (federal and state)
Mercury (state)
Silver (federal and state)
(acute
Selenium (state)
Selenium (federal)
Zinc (federal)
freshwater)
Zinc (state)
Cyanide (federal and state)
SURFACE
Arsenic (federal)
Antimony (federal and state)
Arsenic (state)
WATER
Chromium VI (state)
Cadmium (federal):
Cadmium (state)
Chromium III (federal and
Mercury (federal)
Chromium VI (fed)
Ambient Water
state)
Silver (federal and state)
Lead (federal and state)
Quality Criteria
Copper (federal and state)
Zinc (federal)
Mercury (state)
(chronic
Nickel (federal and state)
Cyanide (federal and state)
freshwater)
Selenium (federal and state)
Zinc (state):
AMBIENT
PM10, annual standard (state)
PM10, annual standard (federal)
AIR
PM10, 24 hour standard (federal
and state)
Ambient Air
Quality
Standards
* Action level.
-------
Table 5-4
Changes in Action-Specific ARARs
Action
Requirement
Source
Solid ;Mr I
Previous
Establishes levels of performance for solid waste disposal
facilities
40 CFR 241.200-211; 1990
Land Disposal of Solid Waste
Current
Regulation repealed in 1996: determined to be "obsolete" and
"no longer necessary" because it is included and/or addressed
by 40 CFR 257 and 40 CFR 258.
61 FR 82 18501; 1996
Design and Operating Requirements for
Owners/Operators of hazardous waste
treatment, storage or disposal facilities
Previous
Requires waste piles to be designed to prevent migrations of
wastes into soil, groundwater or surface water, which includes
a liner and leachate collection and removal system for waste
piles.
40 CFR 264.251; 1991
Current
Requires installation of two or more liners and a leachate
collection and removal system for new waste pile units, lateral
expansion of waste pile units, or replacement or existing
waste pile units where construction commences/reuse
commences after July 29, 1992.
40 CFR 264.251; 2000
Design and Operating Requirements for
Owners/Operators of hazardous waste
treatment, storage or disposal facilities
Previous
Design and operating requirements for new and existing
landfill units to protect ground water and surface water and
for closure/post-closure care, including two liners, leachate
collection systems, run-off management and wind dispersion
of particulates.
40 CFR 264.301; 1991
Current
Regulation revised to include design and operating
requirements for new landfill units and lateral expansion of
landfill units commencing construction after July 29, 1992
and existing landfills beginning reuse after July 29, 1992.
Requires a leachate removal system (with a leak detection
system) in addition to the leachate collection system and a two
part composite bottom liner.
40 CFR 264.301; 2000
Closure and Post-Closure Care
Previous
Outlines post-closure and closure requirements
40 CFR 264.310; 1991
Current
Requires the leak detection system to be monitored and all
other applicable leak detection system requirements be
complied with as part of post-closure care (paragraph (b)(3)).
40 CFR 264.310; 2000
VWVC ARAR evaluation v2.xls: Action Specific
7/10/2002 1 of 2
-------
Table 5-4
Changes in Action-Specific ARARs
Action
Requirement
Source
Methods of Disposal
Previous
ARSD 74:27:03:08; 1990
Current
Regulation Repealed
ARSD 74:27:03:08; 2000
Facility Design and Construction:
Surface Water Control
Previous
Establishes requirement for control of surface waters, storm
runoff, leachate from disposal facility. Required discharges of
retained surface waters to meet the requirements of state
regulation 74:03:17-74:03:26.
ARSD 74:27:12:16; 1990
Current
Regulation modified to require discharges of retained surface
waters from the facility to meet the requirements of 40 CFR
122, as published in 57 FR 11394-11413.
ARSD 74:27:12:16; 2000
Notes:
CFR=Code of Federal Regulations
ARSD= Administrative Record of South Dakota
FR=Federal Register
VWVC ARAR evaluation v2.xls: Action Specific
7/10/2002 2 of 2
-------
Table 5-5
Summary of the Results of the SERA
Medium
Receptor of Interest
(ROI)
Exposure
Pathway
Constituent
Range of
HQ
Values
Further
Evaluation
(Yes/No)
Dissolved lead and zinc
2 to 4
Yes
Surface
Water
Aquatic Invertebrates
and Fish
Direct Contact
Total recoverable arsenic,
copper, lead, mercury,
nickel and zinc
2 to 30
Yes
Mammals
Ingestion
Lead and arsenic
2 to 3
Yes
Benthic Invertebrates
Direct Contact
Antimony, arsenic,
cadmium, chromium,
copper, lead, mercury,
nickel and zinc
2 to 2,000
Yes
Sediment
Avian and
mammalian
piscivores (mink and
kingfisher)
Ingestion
Arsenic
2 to 20
Yes
Avian aquatic
insectivores
(swallow)
Ingestion
Arsenic, chromium and
copper
2 to 30
Yes
Vegetation
Direct Contact
Arsenic, cadmium, copper,
nickel, selenium and zinc
2 to 700
Yes
Soil
Soil Organisms
Direct Contact
Arsenic, cadmium,
chromium, copper,
mercury, nickel, selenium
and zinc
2 to 300
Yes
Avian and
mammalian
insectivores (robin
and shrew)
Ingestion
Arsenic, cadmium,
chromium, and copper
2 to 200
Yes
Avian insectivores
(robin)
Ingestion of
soil organisms
Arsenic, cadmium,
chromium, lead, mercury,
nickel and selenium
2 to 100
Yes
Mammalian
insectivores (shrew)
Ingestion of
soil organisms
Arsenic, cadmium, nickel,
selenium and zinc
2 to 100
Yes
Food web
Mammalian
omnivores (mouse)
Ingestion of
soil organisms
Arsenic and cadmium
2 to 6
Yes
Mammalian
herbivores (deer)
Ingestion of
vegetation
Arsenic
6 to 9
Yes
Avian aquatic
insectivores
(swallow)
Ingestion of
benthic
invertebrates
Arsenic, cadmium,
chromium, copper, lead,
mercury, and selenium
2 to 30
Yes
Table 5-5 SERA Summ. V2 .wpd
-------
Table 5-6
Summary of Data Gaps Identified in the SERA
Receptor
Exposure
Medium
Data Gaps
Potential Data Collection
Benthic
Invertebrates
Sediment
Better definition of extent of sediment
exposures
Additional measurements of COPC
concentrations in sediments
Bioavailability of metals in sediments
Measurements of COPCs in interstitial water
of sediment at seeps
AVS/SEM measurements
Extent of site-specific sediment toxicity
Sediment toxicity testing
Re-evaluation of current community data
Samples of benthic invertebrate community
metrics in comparison to reference
Fish
Surface
water,
sediment
and diet
COPC concentrations in diet
Bioavailability of mercury
Extent of site-specific effects of metals
exposure
Measurement of COPC concentrations in
benthic invertebrates
Tissue measurements of mercury
Re-evaluation of current community data
Fish community structure analyses
Wildlife
Soil,
sediment
and diet
Better definition of exposures and
bioavailability of metals from soils,
sediments and diet
Derivation of site-specific BAFs
Extent of site-specific effects of metals
exposure
Sediment bioaccumulation tests
Constituent concentrations in soil
invertebrates
Constituent concentrations in vegetation
Constituent concentrations in small
mammals
Evaluation of current wildlife census data
Census studies
Vegetation
and Soil
Invertebrates
Soil
Site-specific soil toxicity
Soil toxicity testing
Table 5-6 Data Gaps.doc
-------
Table 5-7
Summary of the Five-Year Review Residential Verification Sampling Results
Property
Sample Number
Arsenic Concentration (mg/kg)
Shuck
5OM-01
75.1
Shuck
5OM-02
12.79**
Shuck
5OM-03
13.01**
Shuck
5OM-04*
12.86**
Shuck
5OM-05*
11.78**
Shuck North
5OM-06
24.88
Shuck North
5OM-07
11.79**
Shuck North
5OM-08*
12.2**
Shuck North
5OM-09*
10.76**
Nelson
5OM-10*
23.92
Nelson
50M-11*
21.42
Nelson
50M-12
11.16**
Nelson
50M-13
12.12**
Nelson
50M-14
10.56**
Nelson
50M-15
10.29**
Alan
50M-16*
46.14
Alan
50M-17*
34.37
Alan
50M-18
42.77
Alan
50M-19
61.22
Alan
5OM-20
12.01**
Alan
50M-21
12.69**
Westberg
50M-22*
12.18**
Westberg
50M-23*
12.36**
Westberg
50M-24
12**
Holsclaw
50M-25
11.34**
Holsclaw
50M-26*
10.03**
Holsclaw
50M-27*
10.19**
Holsclaw
50M-28
56.29
Holsclaw
50M-29
54.78
Holsclaw
5OM-30
119.72
Holsclaw
50M-31
132.16
Holsclaw
50M-32
72.2
*Duplicate Sample "Below Detection Limit
Source: Chadwick et al. (1997)
-------
Table 5-8
Summary Statistics for Surface Water Time Trend Plots
Chemical
Form
USES Station 06436180 (Upstream)
USES Station 06436198 (Downstream)
Slope (mg/L per
year)
p value
R2
Slope (mg/L per
year)
p value
R2
Antimony
Dissolved
-1E-04
0.221
0.020
-2E-04
0.095
0.038
Arsenic
Dissolved
-1E-03
0.005
0.101
-2E-03
0.001
0.146
Total
8E-03
0.590
0.004
1E-02
0.460
0.008
Cadmium
Dissolved
1E-06
0.841
0.001
-1E-05
0.164
0.027
Total
-3E-04
0.000
0.174
-3E-04
0.001
0.141
Copper
Dissolved
-9E-04
0.000
0.268
-2E-04
0.003
0.114
Total
7E-04
0.856
0.0005
1E-03
0.677
0.002
Cyanide
Total
-1E-03
0.444
0.008
1E-04
0.792
0.001
Lead
Dissolved
-8E-04
0.000
0.309
-2E-04
0.350
0.012
Total
2E-03
0.560
0.005
1E-03
0.376
0.011
Mercury
Dissolved
-3E-06
0.001
0.133
-1E-06
0.110
0.035
Total
-3E-06
0.780
0.001
-2E-06
0.707
0.002
Nickel
Dissolved
1E-04
0.275
0.016
-2E-04
0.001
0.148
Total
-7E-04
0.072
0.111
-4E-03
0.491
0.018
Selenium
Dissolved
-2E-04
0.002
0.118
-2E-06
0.968
0.000
Total
-3E-04
0.000
0.266
7E-05
0.222
0.022
Zinc
Dissolved
-4E-04
0.002
0.121
-6E-04
0.006
0.102
Total
4E-03
0.612
0.004
5E-03
0.381
0.011
p value Time trend tests.xls
-------
FIGURES
-------
Location in South Dakota
Belle Fourche
Reservoir
Spearflsh Creekl
*
Gold Run
Creek
-------
Figure 3-2 Schematic Representation of the Geology and
Water-Circulation Pathways in the Whitewood Creek Valley
Whitewood Creek Five-Year Review
TAIL1M01 .
WHITEWOOD
CREEK
I
Source; Cherry et al., 1986 (Part 2 of 3, Figure 4)
-------
Figure 4-1
As Constructed Diagram of the Whitewood Creek Supcrfiinri Site Disposal Site
-------
Figure 4-2
Post-construction Photo of a Soil Disposal Cell, Spring 1994
-------
Souiwc; WDC
-------
Figure 4-4.
Homesite Development Flowchart for the Whitewood Creek Tailings Area'
-------
Figure 4-5
Photos Taken During Disposal Site Operation and Maintenance Activities
October 2000. View of rip-rap bank stabilization area and reseeded area.
Photo taken looking to the north/northwest.
May 2001. Rip-rap at north end of soil disposal cell after placing Whitewood
Creek Soil Samples inside cell. Photo taken looking south/southeast.
-------
Figure 4-6
Unauthorized Rubble Placed Outside of the Disposal Site
Unauthorized rubble prior to disposal, looking west. Note burned material.
-------
Belle Fourche
Reservoir
Belle Fourche
Chadwick - BFR1
Spearfish Creekl
Vale
Siphon Area
Whitewood Creek
WWC-06 - ERT
WWC2 - Chadwick
Chadwick - BFR2
ERT - BFR-R-10
*
Gold Run
Creek
460122 - SDDENR
Pluma
WWC-03 - ERT
460123 - SDDENR
WWC-02 - ERT
460686 - SDDENR
WWC-R-01 - ERT
Highway 14
Map not to scale
Figure 5-1
Sampling Stations Map
-------
Figure 5-2
Time Trend Analyses for Antimony in Surface Water
Page 1 of 10
o.i -
0.01 -
0.001 -
0.0001 -
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
Station 06436198
Antimony
1 -
o.i -
0.01 -
0.001 -
0.0001
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
Station 06436180
Antimony
~ Dissolved
~ A ~ ~ ~ ~ ~
" " - -
4m ~ «~~~~~ ~ ~ ~ ~
~ ~
~ ~ »~
~
~ Dissolved
~ «~ ~ ~ ~
COPC Time Trends.xls:Antimony
7/10/2002
-------
Figure 5-2
Time Trend Analyses for Arsenic in Surface Water
Page 2 of 10
10
Station 06436180
Arsenic
o.i
0.01
0.001
~ Dissolved
I Total
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
10
Station 06436198
Arsenic
o.i
~ Dissolved
I Total
v*
~»*~ ~ ~ ~
0.01
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
COPC Time Trends.xls:Arsenic
7/10/2002
-------
Figure 5-2
Time Trend Analyses for Cadmium in Surface Water
Page 3 of 10
o.oi
Station 06436180
Cadmium
0.001
el
o
U
0.0001
~ Dissolved
I Total
TT1T
II 11 ¦ «« ¦
12/23/1988
5/7/1990
9/19/1991
1/31/1993
6/15/1994 10/28/1995 3/11/1997
7/24/1998
12/6/1999
4/19/2001
0.01
Station 06436198
Cadmium
0.001
0.0001
~ Dissolved
I Total
12/23/1988
5/7/1990
9/19/1991
1/31/1993
6/15/1994
10/28/1995
3/11/1997
7/24/1998
12/6/1999
4/19/2001
COPC Time Trends.xls:Cadmium
7/10/2002
-------
Figure 5-2
Time Trend Analyses for Copper in Surface Water
Page 4 of 10
Station 06436180
Copper
o.i -
0.01 -
0.001
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
1 -
0.1 -
0.01 -
0.001 -
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
Station 06436198
Copper
COPC Time Trends.xls:Copper
7/10/2002
-------
Figure 5-2
Time Trend Analyses for Cyanide in Surface Water
Page 5 of 10
Station 06436180
Cyanide
o.i
~ Total
~
~
~ ~~ ~
~
~
~~ ~
~ ~
0.01
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
Station 06436198
Cyanide
o.i
0.01
0.001
~ Total
~
~ ~
~
~
~ ~
~ ~
~ ~ ~
~ ~
~~ ~
~
~
12/23/1988 5/7/1990
9/19/1991
1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999
4/19/2001
COPC Time Trends.xls:Cyanide
7/10/2002
-------
Figure 5-2
Time Trend Analyses for Lead in Surface Water
Page 6 of 10
o.i
0.01
0.001
0.0001
Station 06436180
Lead
~ Dissolved ¦ Total
¦ ~
w9rr
~««»«<
~ ~ ~ ~ ~ ~
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
Station 06436198
Lead
o.i
0.01
0.001
0.0001
~ Dissolved
I Total
3BBII I i > »» > > ¦-
12/23/1988
5/7/1990
9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
COPC Time Trends.xls:Lead
7/10/2002
-------
Figure 5-2
Time Trend Analyses for Mercury in Surface Water
Page 7 of 10
o.oi -
0.001 -
0.0001 -
0.00001 -
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
0.01 -
0.001 -
0.0001 -
0.00001 -
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
Station 06436180
Mercury
~ Dissolved ¦ Total
Station 06436198
Mercury
COPC Time Trends.xls:Mercury
7/10/2002
-------
Figure 5-2
Time Trend Analyses for Nickel in Surface Water
Page 8 of 10
Station 06436180
Nickel
o.i -
0.01 -
0.001
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
1 -
0.1 -
0.01 -
0.001 -1 1 1 1 1 1 1 1 1
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
~ Dissolved ¦ Total
~ ~ ~ ~ ~ ~ mtm ~ ~ ~ ~ <»~~~ ~ ~
Station 06436198
Nickel
~ Dissolved ¦ Total
~ ~ ~
ttftl t ¦ j t ~ ~ ¦ ~
¦ ¦-
¦ ¦ ¦ ¦ 11 i ~~
m m ¦¦ ¦ ~ ¦
COPC Time Trends.xls:Nickel
7/10/2002
-------
Figure 5-2
Time Trend Analyses for Selenium in Surface Water
Page 9 of 10
o.i
0.01
0.001
0.0001
Stration 06436180
Selenium
~ Dissolved ¦ Total
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
Stration 06436198
Selenium
o.i
0.01
0.001
0.0001
~ Dissolved
I Total
¦ ¦ ¦ ¦ ¦¦¦ ¦ i > I
¦
~ ¦
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
COPC Time Trends.xls:Selenium
7/10/2002
-------
Figure 5-2
Time Trend Analyses of Zinc in Surface Water
Page 10 of 10
10
o.i
0.01
0.001
0.0001
Station 06436180
Zinc
~ Dissolved
I Total
~ ~ ¦
_i < mmt . uuu^mu
~ ~
12/23/1988 5/7/1990
9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
Station 06436198
1
Zinc
¦
~ Dissolved
¦ Total
0.1
¦
¦
¦
¦
" -
¦
0.01
~
\ ~
*
1 t > *1
¦ ~
H ¦
t ~~
l
~l
*\
~
¦
¦
¦
¦
~ ~
~ ~~ ~
~ ~
~
~
¦
¦ ¦ ¦ ¦ ¦
~
~ ~~~~ ~ * *
~ ~
0.001
1 1
1
1
1
1 1
1
12/23/1988
5/7/1990 9/19/1991 1/31/1993
6/15/1994 10/28/1995 3/11/1997 7/24/1998
12/6/1999
4/19/2001
COPC Time Trends.xls:Zinc
7/10/2002
-------
Figure 5-3
Comparison of Time Trend Plots for Antimony in Surface Water with Fish Consumption Criteria
Page 1 of 8
10
oo 0.1
6
s 0.01
0.001
0.0001
Station 06436180
Antimony
"Human Health'Fisfi"Consumption"Criteria"4.3"mg7C '
£» ~ \ ~~
~ ~ ~
~ ~~ ~
~~ ~
~ ~ ~
~ ~
~~~~
~ Dissolved
~ «»~ ~ «~ ~
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
Station 06436198
10 -
Antimony
~ Dissolved
1 -
Human Health Fish Consumption Criteria 4.3 mg/L
tj) 0.1 -
s
c
1
-------
Figure 5-3
Comparison of Time Trend Plots for Arsenic in Surface Water with Fish Consumption Criteria
Page 2 of 8
o.i
J
"6d
0.01
a
o
U
0.001
Station 06436180
Arsenic
~ Dissolved
A ~ ^ ~ ~ ~ ~ ~
Human Health Fish Consumption Criteria 0.00014 mg/L
0.0001
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
0.1
tJ
0.01
§
u
0.001
Station 06436198
Arsenic
~ Dissolved
V V J* ~ A /
~ 7 ~ ~~ ~ ~ ~
~ ~
Human Health Fish Consumption Criteria 0.00014 mg/L
o.oooi
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
COPC Time Trends with HH AWQC.xls:Arsenic
7/10/2002
-------
Figure 5-3
Comparison of Time Trend Plots for Copper in Surface Water with Fish Consumption Criteria
Page 3 of 8
10
o
el
o
U
0.1
0.01
0.001
Station 06436180
Copper
"Huma'n'HealfKFish'ConsumptioriCriteria 1 .TmgTC "
~ ~
~ ~ ~ «~ ~«~~~~~~
~ Dissolved
~ ~~
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
10
Station 06436198
Copper
Dissolved
OJJ
Human Health Fish Consumption Criteria 1.3 mg/L
Ch
o
Id
S3
-------
Figure 5-3
Comparison of Time Trend Plots for Cyanide in Surface Water with Fish Consumption Criteria
Page 4 of 8
1000
Station 06436180
Cyanide
100
10
Q
O
a
O
O
0.1
Total Cyanide
Human Health Fish Consumption Criteria 220 mg/L
«~ ~ ~
~ ~~~; ~% ~~ ~
W A
~ ~~~ ~
~ ~ «~ ~ ~ ~~ ~ *
~~ ~ , ~ ~ , ~ ~
0.01
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
1000
100
J
10
G
O
0.1
0.01
0.001
Station 06436198
Cyanide
"HumanReallK Fish"Consumption Criteria 22tfmg/C '
4» ~~ ~ ~ ~
~ ~ ~~ ~
~ ~
~~ ~
~ Total Cyanide
~
~
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
COPC Time Trends with HH AWQC.xls:Cyanide
7/10/2002
-------
Figure 5-3
Comparison of Time Trend Plots for Mercury in Surface Water with Fish Consumption Criteria
Page 5 of 8
o.oi
Station 06436180
Mercury
^ 0.001
GO
Ch
n>
o
Q o.oooi
0.00001
Dissolved
Human Health Fish Consumption Criteria 0.0017 mg/L
~«* ~ ~ ~ ~
* ~
12/23/1988
5/7/1990
9/19/1991
1/31/1993
6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999
4/19/2001
0.01
0.001
a
U 0.0001
0.00001
Station 06436198
Mercury
~ ~
~~
~ Dissolved
Human Health Fish Consumption Criteria 0.0017 mg/L
~ ~ ~ ~ «»~~~ ~ ~ ~
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
COPC Time Trends withHH AWQC.xls:Mercury
7/10/2002
-------
Figure 5-3
Comparison of Time Trend Plots for Nickel in Surface Water with Fish Consumption Criteria
Page 6 of 8
10
au
el
e!
o
§
o
U
0.1
0.01
0.001
Station 06436180
Nickel
Human Health Fish Consumption Criteria 4.6 mg/L
~ Dissolved
~ ~ ~ ~ ~
~ ~ ~ ~ «»~~~ ~ ~
~
~ ~
~~
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
10
el
"o3
e:
o
Sh
o
U
0.1
0.01
0.001
Station 06436198
Nickel
Human Health Fish Consumption Criteria 4.6 mg/L
~ Dissolved
~ ~
~ ~
~ .
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
COPC Time Trends with HH AWQC.xls:Nickel
7/10/2002
-------
Figure 5-3
Comparison of Time Trend Plots for Selenium in Surface Water with Fish Consumption Criteria
Page 7 of 8
Stration 06436180
100
Selenium
~
Dissolved
10
5 1
DO
a
Human Health Fish Consumption Criteria 11 mg/L
a
¦s01
H
iU
CD
cj 0.01
~ ~
~ ~ «* «»~ «~ ^ ~ ~ .~
~«MM ~ ~~~~ ~ ~ ~~~~ ~ *
0.001
~ ~ «»~ ~ ~ ~
~ ~ ~
~
«~
0.0001
1111111
1 1
12/23/1988
5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998
12/6/1999 4/19/2001
100
10
au
o
0.1
o
el
o
u 0.01
0.001
0.0001
Stration 06436198
Selenium
Human Health Fish Consumption Criteria 11 mg/L
~ ~ ~~ ~~
~ ~~~~~~ «» ~ ~ ~
~~ ~
~ Dissolved
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
COPC Time Trends with HH AWQC.xls:Selenium
7/10/2002
-------
Figure 5-3
Comparison of Time Trend Plots for Zinc in Surface Water with Fish Consumption Criteria
Page 8 of 8
100
10
0.1
0.01
0.001
0.0001
Station 06436180
Zinc
Human Health Fish Consumption Criteria 69 mg/L
~ ~
~ ~
\ ~~
~ \ ~ ~~ *~~~ W* ~
~ ~ ~
>~ ~ ~
~ Dissolved
~ ~
~ V ~
~ ~ ~~
~ ~ ~ ~ ~
~
12/23/1988 5/7/1990 9/19/1991 1/31/1993 6/15/1994 10/28/1995 3/11/1997 7/24/1998 12/6/1999 4/19/2001
100
10
§ 0.1
u
0.01
0.001 +
Station 06436198
Zinc
Human Health Fish Consumption Criteria 69 mg/L
Dissolved
~
~
~
~
~ /~ ~
~ ~~ ~
~ ~ aA
~~ ~
~ ~
~
~
~ ~~~~ ~
12/23/1988
5/7/1990
9/19/1991
1/31/1993
6/15/1994 10/28/1995 3/11/1997
~ ~
~ ~
7/24/1998
12/6/1999 4/19/2001
COPC Time Trends with HH AWQC.xls:Zinc
7/17/2002
------- |