Record of Decision
Olin Mcintosh Site
Operable Unit 2 (OU-2)
Mcintosh, Washington County, Alabama
April 2014
U.S. Environmental Protection Agency
Region 4
61 Forsyth Street S.W.
Atlanta, Georgia 30303
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ERRATA SHEET
This errata sheet lists errors and their correction for the Olin Mcintosh Site, Operable Unit 2,
Record of Decision, dated April 2014.
Location
Error
Correction
p. xii, line 12
TMV Toxicity, Mobility, Volume
p. xii, line 13
TRV Toxicity Reference Value
p. 28, par. 2, line 4
0.010 ug/L at a concentration of
0.011 to 0.0113 ng/L
0.010 |ig/L with concentrations of
0.011 to 0.013 ng/L
p. 46, par. 3, line 11
18,000 cm2 and 14,110 cm2
18,000 cm2 and 14,110 cm2
p. 47, par. 3, line 12
5,700 cm2/event and 4,050
cm2/event, respectively.
5,700 cm2/event and 4,050 cm2/event,
respectively.
p. 47, par. 4, line 16
1.36E+9 m3/kg
1.36 x 109 m3/kg
p. 51, par. 2, line 9
(mg/kg-day)-l
(mg/kg-day)"1
p. 52, par. 2, line 13
(e.g., 2x10-5)
(e.g., 2 x 10"5)
p. 52, par. 3, line 17
1x10-6
lxlO"6
p. 53, par. 2, line 4
10-6 to 10-4
10"4to 10"6
p. 53, par. 5, line 19
2.3E-05
2.3 x 10"5
p. 54, par. 2, line 8
Uncertainity
Uncertainty
p. 57, par. 1, line 8
3.2E-05 to 2.0E-06
3.2 x 10"5 to 2.0 x 10"6
p. 58, par. 3, line 25
COCCs
COCs
p. 65, par. 3, line 20-27
• Alabama red-bellied turtle,
Pseudemys alabamensis -
Endangered
• Alabama sturgeon,
Scaphirhyncus suttkusi -
Endangered, Critical Habitat
in Alabama River
• Bald eagle, Haliaeetus
leucocephalus - BGEPA
• Black pine snake, Pituophis
melanoleucus lodingi -
Candidate
• Gopher tortoise, Gopherus
polyphenols - Threatened
• Gulf sturgeon, Acipenser
oxyrinchus desotoi -
Threatened
• Louisiana quillwort, Isoetes
louisianensis - Endangered
• Alabama red-bellied turtle,
Pseudemys alabamensis -
Endangered
• Alabama sturgeon,
Scaphirhyncus suttkusi -
Endangered, Critical Habitat
in Alabama River
• Bald eagle, Haliaeetus
leucocephalus - BGEPA
• Black pine snake, Pituophis
melanoleucus lodingi -
Candidate
• Gopher tortoise, Gopherus
polyphemus - Threatened
• Gulf sturgeon, Acipenser
oxyrinchus desotoi -
Threatened
• Louisiana quillwort, Isoetes
louisianensis - Endangeredp.
p.66, par. 1, line 1-2
• West Indian manatee,
Trichechus manatus - MMPA
• Wood stork, Mycteria
americana - Endangered
• West Indian manatee,
Trichechus manatus - MMPA
• Wood stork, Mycteria
americana - Endangered
p. 67, par. 2, line 9
comprehensive of biological
comprehensive biological
p. 94, par. 2, line 6
0.28 - 0.43 in
0.28 - 0.43 mg/kg in
1 of 2
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ERRATA SHEET
This errata sheet lists errors and their correction for the Olin Mcintosh Site, Operable Unit 2,
Record of Decision, dated April 2014.
p. 94, par. 3, line 15
RG 0.64 in whole body predatory fish
RG 0.64 mg/kg in whole body
predatory fish
p. 104, par. 3, line 21
barrier
barrier.
p. 109, par. 2, line 4
fish tissue with time.
fish tissue over time.
p. 139, par. 2, line 15
WQC of 0.12 ng/L.
WQC of 0.012 ng/L.
p. 152, par. 2, line 18
0.23 in tissues
0.23 mg/kg in tissues
p. 156, line 4-8
Rasmussen. 1996. University of
Florida Book of Insect Records.
Chapter 20 Least Oxygen Dependent.
Available:
(httD ://ufbir.ifas.ufl .edu/ChaD20 .htm)
Rasmussen. 1996. University of
Florida Book of Insect Records.
Chapter 20 Least Oxygen Dependent.
Available:
fhtto:// ufbi r. ifas ,ufl ,cdu/ChaD2().htm)
Soil and Water Conservation Society
of Metro Halifax. 2008.
(http://\vww. chebucto .ns. ca/ ccn/info/
Science/SWCS/ZOOBENTH/BENT
HOS/xxv.html).
Soil and Water Conservation Society
of Metro Halifax. 2008.
(http://\vww. chebucto .ns. ca/ccn/info/S
cience/SWCS/ZOOBENTH/BENTHO
S/xxv.htmD.
Table 26, Notes
3 Ont LEL = Ontario Lowest Effects
Level: Guidelines for the
Protection and Management of
Aquatic Sediment Quality in
Ontario. D. Persaud , R.
laagumagi, and A. Hayton.
Ontario Ministry of the
Environment, Ontario, August
1993.
NOAA ER-L = National Oceanic
and Atmospheric Administration
Effects Range -Low
SQC= Sediment Quality Criteria
PEC = Sediment Probable Effects
Concentration from McDonald et
al 2000. Development and
Evaluation of Consensus-based
Sediment Quality Guidelines for
Freshwater Ecosystems. Arch.
Contam. Toxicol. 39: 20-31.
WSRC = Ecological screening value
for sediment from Westinghouse
Savannah River Company WSCR-
TR-98-00110 (2000)
EPA R4 = Ecological Screening Value
from EPA Region 4
NAWQC = National Ambient Water
Quality Criterion
Table 28, row 4
0.38-0.47 (protection of piscivorous
birds)
0.32 - 0.91 (protection of piscivorous
birds)
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Record of Decision
Olin Mcintosh OU-2 Site
Contents
PART 1: DECLARATION 1
1.1 SITE NAME AND LOCATION 1
1.2 STATEMENT OF BASIS AND PURPOSE 1
1.3 ASSESSMENT OF SITE 2
1.4 DESCRIPTION OF SELECTED REMEDY 2
1.5 STATUTORY DETERMINATIONS 4
1.6 ROD DATA CERTIFICATION CHECKLIST 5
1.7 AUTHORIZING SIGNATURES 6
PART 2: DECISION SUMMARY 7
2.1 SITE NAME, LOCATION, AND BRIEF DESCRIPTION 7
2.2 SITE HISTORY AND ENFORCEMENT ACTIVITIES 7
2.3 COMMUNITY PARTICIPATION 12
2.4 SCOPE AND ROLE OF OPERABLE UNIT OR RESPONSE ACTION 14
2.5 SITE CHARACTERISTICS 16
2.5.1 Site Setting 16
2.5.1.1 Surface Water Features 16
2.5.1.2 Geology/Hydrogeology 20
2.5.2 Conceptual Site Model 23
2.5.3 Nature and Extent of Contamination 27
2.5.3.1 Groundwater 27
2.5.3.2 Floodplain Soil 28
2.5.3.3 Sediment 31
2.5.3.4 Wind-Driven Resuspension Study and Model 34
2.5.3.5 Surface Water 35
2.5.3.6 Biota 36
2.5.4 Evaluation of Sedimentation Rate 39
2.5.5 Debris Evaluation 40
2.6 CURRENT AND POTENTIAL FUTURE LAND AND RESOURCE USES 41
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Olin Mcintosh OU-2 Site
Contents (continued)
2.7 SUMMARY OF SITE RISKS 41
2.7.1 Human Health Risk Assessment 42
2.7.1.1 Chemicals of Concern 42
2.7.1.3 Exposure Assessment 44
2.7.1.4 Toxicity Assessment 48
2.7.1.5 Risk Characterization 50
2.7.2 Ecological Risk Assessment 57
2.7.2.1 Chemicals of Potential Concern (COPCs) 57
2.7.2.2 Exposure Assessment 60
2.7.2.3 Ecological Effects Assessment and Measurement Endpoints 67
2.7.2.4 Ecological Risk Characterization 86
2.7.2.5 Ecological Risk Assessment Summary 88
2.8 REMEDIAL ACTION OBJECTIVES 93
2.9 DESCRIPTION OF ALTERNATIVES 95
2.9.1 Alternative 1: No Action 95
2.9.2 Alternative 2A: In Situ Capping, Institutional Controls (ICs) and Engineering
Controls (ECs) 96
2.9.3 Alternative 2B: In situ Capping, Dry Capping, ICs and ECs 97
2.9.4 Alternative 2C: Dry Capping, ICs and ECs 98
2.9.5 Alternative 3: Debris Removal, Dredging, Dewatering, Onsite or Offsite
Disposal, ICs and ECs 99
2.10 DETAILED ANALYSIS OF ALTERNATIVES 101
2.10.1 Alternative 1: No Action 101
2.10.1.1 Overall Protection of Human Health and the Environment 101
2.10.1.2 Compliance with ARARs 102
2.10.1.3 Long-Term Effectiveness 102
2.10.1.4 Short-Term Effectiveness 102
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Contents (continued)
2.10.1.5 Reduction of TMV through Treatment 102
2.10.1.6 Implementability 102
2.10.1.7 Cost 102
2.10.1.8 State/Support Agency Acceptance 102
2.10.1.9 Community Acceptance 103
2.10.2 Alternative 2A- In Situ Capping, ICS, and ECS 103
2.10.2.1 Overall Protection of Human Health and the Environment 103
2.10.2.2 Compliance with ARARs 104
2.10.2.3 Long-Term Effectiveness 104
2.10.2.4 Short-Term Effectiveness 106
2.10.2.5 Reduction of TMV Through Treatment 107
2.10.2.6 Implementability 108
2.10.2.7 Cost 109
2.10.2.8 State/Support Agency Acceptance 111
2.10.2.9 Community Acceptance 111
2.10.3 Alternative 2B - In Situ Capping, Dry Cappings, ICS and ECS 111
2.10.3.1 Overall Protection of Human Health and the Environment 111
2.10.3.2 Compliance with ARARs 111
2.10.3.3 Long-Term Effectiveness 112
2.10.3.4 Short-Term Effectiveness 112
2.10.3.5 Reduction of TMV Through Treatment 113
2.10.3.6 Implementability 113
2.10.3.7 Cost 114
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Olin Mcintosh OU-2 Site
Contents (continued)
2.10.3.8 State/Support Agency Acceptance 116
2.10.3.9 Community Acceptance 117
2.10.4 Alternative 2C- Dry Cappings, ICS, and ECS 117
2.10.4.1 Overall Protection of Human Health and the Environment 117
2.10.4.2 Compliance with ARARs 117
2.10.4.3 Long-Term Effectiveness 117
2.10.4.4 Short-Term Effectiveness 117
2.10.4.5 Reduction of TMV Through Treatment 118
2.10.4.6 Implementability 119
2.10.4.7 Cost 119
2.10.4.8 State/Support Agency Acceptance 121
2.10.4.9 Community Acceptance 122
2.10.5 Alternative 3- Debris Removal, Hydraulic Dredging, Dewatering, Onsite or
Offsite Disposal, ICS, and ECS 122
2.10.5.1 Overall Protection of Human Health and the Environment 122
2.10.5.2 Compliance with ARARs 123
2.10.5.3 Long-Term Effectiveness 123
2.10.5.4 Short-Term Effectiveness 124
2.10.5.5 Reduction of TMV Through Treatment 124
2.10.5.6 Implementability 124
2.10.5.7 Cost 125
2.10.5.8 State/Support Agency Acceptance 127
2.10.5.9 Community Acceptance 128
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Olin Mcintosh OU-2 Site
Contents (continued)
2.11 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 128
2.11.1 Overall Protection of Human Health and the Environment 128
2.11.2 Compliance with ARARs 129
2.11.3 Long-Term Effectiveness 131
2.11.4 Short-Term Effectiveness 131
2.11.5 Reduction of TMV through Treatment 131
2.11.6 Implementability 131
2.11.7 Cost 132
2.11.8 State/Support Agency Acceptance 132
2.11.9 Community Acceptance 132
2.11.10 Summary 132
2.12 PRINCIPAL THREAT WASTE 133
2.12.1 Human Health and Ecological Risk Summary 135
2.12.2 Toxicity 136
2.12.3 Mobility 138
2.12.4 Containment 140
2.12.5 Source Material 140
2.12.6 Summary of Principal Threat Waste Analysis 141
2.13 SELECTED REMEDY 141
2.13.1 Summary of the Rationale for the Selected Remedy 141
2.13.2 Description of the Selected Remedy 142
2.13.3 Summary of the Estimated Costs 144
2.13.4 Expected Outcomes of the Selected Remedy 145
2.14 STATUTORY DETERMINATIONS 146
2.14.1 Protection of Human Health and the Environment 147
2.14.2 Compliance with ARARs 147
2.14.3 Cost Effectiveness 148
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Olin Mcintosh OU-2 Site
Contents (continued)
2.14.4 Utilization of Permanent Solutions and Alternative Treatment (or Resource
Recovery) Technologies to the Maximum Extent Practicable 149
2.15 DOCUMENTATION OF SIGNIFICANT CHANGES 153
PART 3: REFERENCES 155
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LIST OF APPENDICES
APPENDIX 1 EXPLANATION OF REMEDIAL GOAL DERIVATIONS
AND MODIFICATIONS
APPENDIX 2 STATE CONCURRENCE LETTER
APPENDIX 3 RESPONSIVENESS SUMMARY
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LIST OF TABLES
Table Description
1 Data Use Matrix for Current Olin OU-2 Reports
2 Analytical Results Summary for Historical Surface Water,
Sediment, and Soil Samples
3 Floodplain Soil Analytical Results (2010)
4 Sediment Data Summary by Transect
5 Sediment Core Analytical Results - Coarse Cores
6 Sediment Core Analytical Results - Fine Cores
7 Surface Water Analytical Results (years 2006, 2008, and 2009)
8 Vegetation Analytical Results (2010)
9 Spider and Insect Analytical Results (2010)
10 Historical Fish Tissue Data (1986 - 2001)
11 Recent Fish Tissue Data (2003-2010)
12 Other Biota Analytical Results
13 Vegetation and Land Cover Types
14 Human Health Exposure Pathways
15 Summary of Chemicals of Potential Concern and Medium-
Specific Exposure Point Concentrations
16 Cancer Toxicity Data Summary. Pathway: Ingestion, Dermal
17 Non-Cancer Toxicity Data Summary. Pathway: Ingestion, Dermal
18 Human Health Risk Characterization Summary - Non-
Carcinogens
19 Human Health Risk Characterization Summary - Non-
Carcinogens
20 Human Health Risk Characterization Summary - Non-
Carcinogens
21 Human Health Risk Characterization Summary - Non-
Carcinogens
22 Human Health Risk Characterization Summary - Carcinogen
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LIST OF TABLES (continued)
Table Description
23 Human Health Risk Characterization Summary - Carcinogen
24 Human Health Risk Characterization Summary - Carcinogen
25 Human Health Risk Characterization Summary - Carcinogen
26 Occurrence, Distribution, and Selection of Chemicals of Concern
27 Ecological Exposure Pathways of Concern
COC Concentrations Expected to Provide Adequate Protection
28
of Ecological Receptors
29 Cleanup Levels for Chemicals of Concern
30 Cost Estimate Summary
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LIST OF FIGURES
Figure Description
1 Olin Mcintosh OU2 Location Map
2 Operable Unit Locations
3 Olin Mcintosh OU 2 2006 Bathymetric Survey
4 Cross Section Locations
5 Conceptual Cross Section Diagram (North-South)
6 Geologic Cross-Section (West-East) of Olin Basin and
Section Locations
7 Micro-well, Piezometer, and 2009 Sediment Core Locations
8 Site Conceptual Exposure Model OU-2
9 Conceptual Cross Section Diagram with Sediment Cores
10 Locations of Mercury Samples in Floodplain Soil
11 Locations of Methylmercury Samples in Floodplain Soil
12 Locations of HCB Samples in Floodplain Soil
13 Locations of DDTR Samples in Floodplain Soil
14 Mercury Isoconcentration Map in 2009: Basin and Round
Pond
15 Methylmercury Isoconcentration Map: Basin and Round Pond
16 Sediment Sample Locations and HCB Results: Comparison
of 2009 to Historical Results
17 Sediment Sample Locations and DDTr/DDTR Results:
Comparison of 2009 to Historical Results
18 Sediment Core and Porewater Sample Collection Locations
19 Surface Water Sample Locations in 2009: Basin and Round
Pond
20 Terrestrial Vegetation Sampling Locations and COC
Concentrations
21 Insect Sampling Locations and COC Concentrations
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LIST OF FIGURES (continued)
Figure Description
22 Generalized Food Web Model
23 Site Specific Food Web Model
24 Mercury Target Sediment Concentrations Protective of
Receptor Based on Risk from Forage and Predatory Fish
25 DDTR Target Sediment Concentrations Protective of
Receptor Based on Risk from Forage and Predatory Fish
26 Mercury Target Soil Concentrations Protective of the Carolina
Wren
27 DDTR Target Soil Concentrations Protective of the Carolina
Wren
28 Mercury Target Fish Concentrations Protective of Fish,
Piscivorous Birds, and Humans
29 DDTR Target Fish Concentrations Protective of Fish and
Piscivorous Birds
30 Mercury Remedial Footprint for Capping Alternatives 2A and
2C (> 1.6 to 10.7 mg/kg Mercury)
31 HCB (2009) Isocontour Map with Mercury Remedial Footprint
(>1.6 to 10.7 mg/kg Mercury)
32 DDTR (2009) Isocontour Map with Mercury Remedial
Footprint (>1.6 to 10.7 mg/kg Mercury)
33 Remedial Footprint for Capping Alternative 2B (In-Situ/Dry
Capping Hybrid)
34 Remedial Footprint for Dredging: 0 - 1 Foot Interval
35 Remedial Footprint for Dredging (Alternative 3): 1 - 2 Foot
Interval
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LIST OF FIGURES (continued)
Figure Description
36 Remedial Footprint for Dredging (Alternative 3): 2 - 3 Foot
Interval
37 Remedial Footprint for Dredging (Alternative 3): 3 - 4 Foot
Interval
38 Conceptual Sheet Pile Wall and Locations
39 Remediation Footprint
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ACRONYMS AND ABBREVIATIONS
°C degree Celsius
°F degree Fahrenheit
|jm micrometer or micron
cm3/g cubic centimeter per gram
5YRR 5-Year Review Report
ADCNR Alabama Department of Conservation and Natural Resources
ADEM Alabama Department of Environmental Management
AGS Alabama Geological Survey
ALDNR Alabama Department of Natural Resources
AOC Administrative Order on Consent
ARARs Applicable or Relevant and Appropriate Requirements
ATSDR Agency for Toxic Substances and Disease Registry
AUF Area Use Factor
AWQC Ambient Water Quality Criteria
BAF Bioaccumulation Factor
BGEPA Bald and Golden Eagle Protection Act
BHC model Bachmann-Hoyer-Canfield model
BRA Baseline Risk Assessment
BMP Best Management Practice
BSAF Biota-sediment Accumulation Factor
CD Consent Decree
CDI Chronic Daily Intake
CERCLA Comprehensive Environmental Response, Compensation and Liability Act
CERCLIS Comprehensive Environmental Response, Compensation, and Liability
Information System
cm centimeter
COC Chemical of Concern
COPC Chemical of Potential Concern
CPC Crop Protection Chemicals
CSF Carcinogenic Slope Factor
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ACRONYMS AND ABBREVIATIONS (continued)
CSM Conceptual Site Model
CWA Clean Water Act
Cy Cubic Yards
DDD Dichlorodiphenyldichloroethane
DDE Dichlorodiphenyldichloroethylene
DDT Dichlorodiphenyltrichloroethane
DDTr p,p'-isomers of DDT, DDE, and DDD
DDTR Total dichlorodiphenyl choroethanes (Sum of p,p'-DDT; o,p'-DDT; p,p'-
DDE; o,p'-DDE; p,p'-DDD and o.p'-DDD)
ECs Engineering Controls
EPA United States Environmental Protection Agency
EPC Exposure Point Concentration
ERA Ecological Risk Assessment
ESPP Enhanced Sedimentation Pilot Project
FS Feasibility Study
g/day grams per day
Gl Gastrointestinal
HCB Hexachlorobenzene
HDPE High Density Polyethylene
HHRA Human Health Risk Assessment
HI Hazard Index
HQ Hazard Quotient
ICs Institutional Controls
IUR Inhalation Unit Risk
L/hr liter per hour
LOAEL Low Observed Adverse Effect Level
MCL Maximum Contaminant Level
MDL Method Detection Limit
NAVD88 North American Vertical Datum of 1988
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ACRONYMS AND ABBREVIATIONS (continued)
NCP
National Oil and Hazardous Substances Pollution Contingency Plan
NOAEL
No Observed Adverse Effect Level
NPDES
National Pollutant Discharge Elimination System
NPL
National Priorities List
NSR
Net Sedimentation Rate
NTU
Nephelometric Turbidity Unit
NWS
National Weather Services
O&M
Operation and Maintenance
OM&M
Operation, Maintenance, and Monitoring
Olin
Olin Corporation
ORP
Oxidation Reduction Potential
OU
Operable Unit
OU-1
Olin Mcintosh Operable Unit 1
OU-2
Olin Mcintosh Operable Unit 2
PCNB
Pentachloronitrobenzene
PPE
Personal Protective Equipment
PRG
Permissible Remediation Goal
PTW
Principal Threat Waste
02
Alluvial Aquifer of the Alluvial Sediments
R
Riverine Deposits
RAO
Remedial Action Objective
RCRA
Resource and Conservation and Recovery Act
RfC
Reference Concentration
RfD
Reference Dose
RGO
Remedial Goal Option Report
RGs
Remediation Goals
Rl
Remedial Investigation
RM
River Mile
RME
Reasonable Maximum Exposure
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ACRONYMS AND ABBREVIATIONS (continued)
ROD Record of Decision
SARA Superfund Amendments and Reauthorization Act of 1986
SERAFM Spreadsheet-based Ecological Risk Assessment for the Fate of Mercury
SF Slope Factor
SLERA Screening Level Ecological Risk Assessment
SPLP Synthetic Precipitation Leaching Procedure
SWMUs Solid Waste Management Units
TAG Technical Assistance Group
TBC To Be Considered
TCAN Trichloroacetonitrile
TCLP Toxicity Characteristic Leaching Procedure
TMV Toxicity, Mobility, Volume
TRV Toxicity Reference Value
Terrazole 5-ethoxy-3trichloromethyl-1,2,4-thiadizole
TDS Total Dissolved Solids
Tm1 The Miocene Confining Unit
TOC Total Organic Carbon
TRM Tombigbee River Mile
TSS Total Suspended Solids
t-TEL tissue threshold effects level
UCL Upper Confidence Limit
USACE United States Army Corps of Engineers
USEPA United States Environmental Protection Agency
USFWS United States Fish and Wildlife Service
WEFH Wildlife Exposure Factors Handbook
WSE Water Surface Elevations
WQC Water Quality Criteria
April 2014 xii
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PART 1
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Record of Decision
Olin Mcintosh OU-2 Site
PART 1: DECLARATION
1.1 SITE NAME AND LOCATION
The Olin Corporation (Mcintosh Plant) Superfund Site, Operable Unit 2 (OU-2) is
located adjacent to and east of the Olin Chlor-Alkali facility at 1638 Industrial Road in
Mcintosh, Washington County, Alabama. The Site was entered into the Comprehensive
Environmental Response, Compensation, and Liability Information System (CERCLIS)
database on July 2, 1979 and the identification number of the Site in CERCLIS is:
#ALD008188708. The Site was listed on the NPL in September of 1984. Because the
problems at the Olin Site are complex, the Site was organized into two operable units
(OUs): OU-1- the active production facility, Solid Waste Management Units (SWMUs),
and the upland area of the Olin property; and OU-2 - the Olin Basin located east of the
main plant area and adjacent to the Tombigbee River, a floodplain and a wastewater
ditch leading to the Basin. OU-2 consists of approximately 209 acres of open ponded
water and seasonally flooded wetland. Under base water flow (non-flooded stage)
conditions, the open water portion of OU-2 consists of the 76 acre Olin Basin (the
Basin), and the 4 acre Round Pond. Olin Basin and Round Pond drain into the
Tombigbee River through an inlet channel at the south end of the Basin. OU-2 also
includes a wastewater ditch (about 6,000 linear feet) that extends from the main plant to
the Basin. This ditch formerly discharged into the southwest corner of the Basin, but
currently discharges into the inlet channel to the Tombigbee River.
1.2 STATEMENT OF BASIS AND PURPOSE
This decision document, presents the Selected Remedy for Operable Unit Two (OU-2)
of the Olin Corporation (Mcintosh Plant) Site, Mcintosh, Alabama, (the Site) which was
chosen in accordance with the Comprehensive Environmental Response,
Compensation and Liability Act of 1980 ("CERCLA"), as amended by the Superfund
Amendments and Reauthorization Act of 1986 ("SARA") 42 U.S.C. Section 9601 et
seq., and to the extent practicable, the National Contingency Plan ("NCP") 40 CFR Part
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Olin Mcintosh OU-2 Site
300. This decision is based on the Administrative Record for the Olin OU-2 Site.
The Alabama Department of Environmental Management (ADEM) concurs with the
Selected Remedy.
1.3 ASSESSMENT OF SITE
The response action selected in this Record of Decision (ROD) is necessary to protect
the public health or welfare or the environment from actual or threatened releases of
hazardous substances into the environment.
1.4 DESCRIPTION OF SELECTED REMEDY
Based on the information currently available, the Environmental Protection Agency
(EPA) believes the selected remedy of in-situ capping of contaminated sediments and
soil meets the threshold criteria and provides the best balance of tradeoffs among the
other alternatives with respect to the balancing and modifying criteria. In compliance
with CERCLA Section 121(b), this alternative will be protective of human health and the
environment, comply with ARARs, be cost effective, will use permanent solutions and
alternative treatment technologies or resource recovery technologies to the maximum
extent practicable. Capping of mercury contaminated sediments has been
demonstrated to be reliable for this type of contamination and provides an element of
treatment to reduce mobility and toxicity (bioavailability) through physical isolation,
stabilization, and chemical immobilization of the contaminants under the cap.
The NCP establishes an expectation that EPA will use treatment to address the
principal threats posed by a site whenever possible (NCP §300.430(a)(1)(iii)(A)). The
Olin OU-2 mercury contaminated sediments are not readily classifiable as principal
threat wastes despite the inherent toxicity of mercury and demonstrated mobility which
has contaminated surface water. Although active treatment is not included as a primary
component in the selected remedy, the cap may include reactive materials that will
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Olin Mcintosh OU-2 Site
sequester mercury and prevent it from migrating through the cap. Capping alternatives
have been demonstrated to be reliable containment remedies for this type of
contamination in submerged sediments.
The major components of the remedy include:
• Multi-layered Cap. A multi-layered cap applied in-situ over approximately 80
acres of sediment exceeding the sediment cleanup levels. The cap will consist of
three layers: 1) a mixing zone, 2) an effective cap layer, and 3) a habitat layer.
The capping materials and their thicknesses will be determined during remedial
design. These capping materials will be physically and chemically compatible
with the environment in which they are placed. Geotechnical parameters will be
evaluated to ensure compatibility among cap components, native sediment, and
surface water. The placement method will minimize short-term risk from the
release of contaminated pore water and resuspension of contaminated sediment
during cap placement. Reactive materials may be used to reduce the potential for
contaminants to migrate through the cap.
~ Additional Sampling and Analyses. Additional sampling and analyses will be
performed in the channel connecting Round Pond to the Basin and the perimeter
of the Round Pond floodplain soils that are often inundated, as well as the former
wastewater and discharge ditch, to further refine the remedial footprint.
Depending on the results of this characterization, these floodplain soil areas may
require installation of a cap.
~ Institutional Controls. The institutional controls (deed and restrictive covenant)
that are currently in place as a result of OU-1 (Operable Unit 1) will be amended
to include the OU-2 remedial footprint and use restrictions. Also, engineering
controls, such as warning signs, including fish advisory signage, fencing, and
security monitoring will be implemented to restrict access and prevent exposures
to human receptors.
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~ Construction Monitoring. Construction monitoring for capping will be designed
to ensure that the design plans and specifications are followed in the
placement of the cap and to monitor the extent of any contaminant releases
during cap placement. Construction monitoring will likely include interim and
post-construction cap material placement surveys, sediment cores, sediment
profiling camera, and chemical resuspension monitoring for contaminants. In
the initial period following cap construction, sediment samples will be taken to
confirm that cleanup levels were achieved and benthic community
assessments will be performed to evaluate restoration efforts.
~ Maintenance. Maintenance of the in-situ cap will include the repair and
replenishment of the layers where necessary to prevent releases of
contaminants.
~ Long-Term Monitoring. Long-term monitoring will include physical, chemical, and
biological measurements in various media to evaluate long-term remedy
effectiveness in achieving remedial action objectives (RAOs), attaining cleanup
levels, and in reducing human health and environmental risk. In addition, long-
term monitoring data is needed to complete the five-year review process.
1.5 STATUTORY DETERMINATIONS
The Selected Remedy is protective of human health and the environment, complies with
Federal and State requirements that are applicable or relevant and appropriate to the
remedial action (unless justified by a waiver), is cost-effective, and utilizes permanent
solutions and alternative treatment (or resource recovery) technologies to the maximum
extent practicable.
The remedy in this OU does not satisfy the statutory preference for treatment as a
principal element of the remedy. In-situ treatment without a cap was not considered
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practicable considering the extent, high volumes, and location of the contaminated
sediments in the Basin. The toxicity and mobility of mercury in sediments will be
significantly reduced through physically and chemically isolating the contaminated
sediments from the aquatic environment. In-situ caps are generally accepted as reliable
containment for contaminated sediment.
Because this remedy will result in hazardous substances, pollutants, or contaminants
remaining on-site above levels that allow for unlimited use and unrestricted exposure, a
CERCLA statutory review will be conducted every five years after initiation of remedial
action to ensure that the remedy is, or will be, protective of human health and the
environment.
1.6 ROD DATA CERTIFICATION CHECKLIST
The following information is included in the Decision Summary section of this Record of
Decision. Additional information can be found in the Administrative Record file for this
site.
S Chemicals of concern and their respective concentrations.
S Baseline risk represented by the chemicals of concern.
S Cleanup levels established for chemicals of concern and the basis for these
levels.
S How source materials constituting principal threats are addressed.
S Current and reasonably anticipated future land use assumptions and current
and potential future beneficial uses of ground water used in the baseline risk
assessment and ROD.
S Potential land and groundwater use that will be available at the site as a result
of the Selected Remedy.
S Estimated capital, annual operation and maintenance (O&M), and total
present worth costs, discount rate, and the number of years over which the
remedy cost estimates are projected.
S Key factor(s) that led to selecting the remedy that demonstrate how the
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Selected Remedy provides the best balance of tradeoffs with respect to the
balancing and modifying criteria, highlighting criteria key to the decision.
1.7 AUTHORIZING SIGNATURES
This ROD documents the selected remedy for sediments and soils at the Olin OU-2
Superfund Site. This remedy was selected by EPA with concurrence from ADEM.
Franklin E. Hi!
Superfund Division
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PART 2: DECISION SUMMARY
2.1 SITE NAME, LOCATION, AND BRIEF DESCRIPTION
The Olin Corporation Mcintosh Plant is located approximately one mile east-southeast
of the town of Mcintosh, in Washington County, Alabama. For an area location map and
general Site map, see Figure 1. The Olin property is bounded on the east by the
Tombigbee River; on the west by land not owned by Olin; on the north by the Ciby-
Geigy Superfund Site; and on the south by River Road. The EPA is the lead regulatory
agency. Olin Corporation has funded the response actions at the Site.
The Olin plant is an active chemical production facility. The main plant and associated
Olin properties cover approximately 1500 acres, with active plant production areas
occupying about 60 acres. Olin has produced chlor-alkali chemicals at Mcintosh since
1952, first with a mercury-cell process, shut down since 1982, and now with diaphragm-
cell and membrane processes. Crop protection chemicals (CPC), basically chlorinated
organics, were produced from 1952 to 1982.
Because the problems at the Olin Site are complex, the Site has been organized into
two operable units (OUs): OU-1- the active production facility, Solid Waste Management
Units (SWMUs), and the upland area of the Olin property; and OU-2 - the Olin Basin
located east of the main plant area and adjacent to the Tombigbee River, a floodplain
and a wastewater ditch leading to the Basin. Olin OU-2 is located to the east of the main
plant site (Figure 2).
2.2 SITE HISTORY AND ENFORCEMENT ACTIVITIES
Olin Corporation (Olin) operated a mercury cell chlor-alkali plant (constructed in 1951)
on a portion of the Site from 1952 through December 1982. In 1952, Calabama
Chemical Company began operation of a chlorinated organics plant on property
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immediately south of the Olin plant. In 1954, Olin acquired Calabama Chemical and in
1955 began construction of a pentachloronitrobenzene (PCNB) plant on the acquired
property. The plant was completed and PCNB production was started in 1956. The
Mcintosh plant was expanded in 1973 to produce trichloroacetonitrile (TCAN) and 5-
ethoxy-3trichloromethyl-1,2,4-thiadiazole (Terrazole). The Terrazole® manufacturing
areas were collectively referred to as the Crop Protection Chemicals (CPC) plant. In
1978, Olin began operation of a diaphragm cell caustic soda/chlorine plant, which is still
in operation. In 1982, Olin replaced the mercury-cell facility with a diaphragm and
membrane cell system that eliminated mercury from the manufacturing process. HCB
was no longer produced when Olin discontinued operation of the CPC facility in 1982.
Both facilities were demolished in 1984 with demolition debris from the mercury-cell
process sent to a secure off-site landfill. The areas of each operation were capped. As a
result of these actions, mercury and HCB were eliminated from the production process
by 1982 through operational changes at the facility.
In September 1984, Olin's Mcintosh plant Site was place on the National Priority List
(NPL) of CERCLA or "Superfund." Groundwater contamination at the Site had been
established based on the results of various investigations. In listing the Site on the NPL,
the EPA found the following hazardous substances associated with the Site: mercury,
gamma-hexachlorocyclohexane, hexachlorobenzene, 1,2,4 trichlorobenzene, and 1,4
dichlorobenzene. Mercury contamination was evidently caused by the operation of the
mercury chlor-alkali plant during the period of 1952 to 1982.
Source control measures at the Olin Mcintosh facility began in the early 1980s and
extended into the early 2000s. Starting in 1984, Olin clean closed nine Resource and
Conservation and Recovery Act (RCRA) hazardous waste management units at the
Site. One RCRA unit was closed with waste left in place. These measures were
approved by the Alabama Department of Environmental Management (ADEM) and/or
the EPA.
• Clean closure of Mercury Waste Drum Area and Waste Pile Storage Area
• Clean closure of pH Pond
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• Clean closure of Chromium Storage Area
• Clean closure of Flammable Drum Storage Area
• Clean closure of PCB and HCB Storage Building
• Closure of Stormwater Pond
• Closure of Filter Backwash Pond
• Closure of the Weak Brine Pond
• Closure of the TCAN Hydrolyzer
These closure activities were conducted under RCRA, which is currently administered
and monitored by ADEM under a RCRA Part B Permit. The current permit indicates that
46 of 53 SWMUs and 4 of 7 areas of concern require no further action. All other
SWMUs and areas of concern have approved on-going remedies in place.
Extensive groundwater investigations were conducted in the early 1980s. In 1987, Olin
initiated groundwater recovery and treatment for mercury and other chemicals of
concern (COCs) through five corrective action recovery wells with well-head treatment
under RCRA.
In 1989, the EPA and Olin entered into an Administrative Order on Consent (AOC) for
Olin to conduct a Remedial Investigation/Feasibility Study (RI/FS) under the EPA's
oversight.
In 1990, under a Superfund Administrative Order on Consent, Olin removed 11,407 tons
of HCB contaminated soil from the Site.
Olin conducted additional groundwater studies in the early 1990s as part of OU-1. In
1995, Olin entered into a Consent Decree (CD) with the EPA to expand and centralize
the groundwater recovery and treatment system for OU-1 under CERCLA. The
expanded groundwater recovery system was installed in 2000/2001 and included
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additional corrective action recovery wells and centralized treatment units. Operations
and monitoring of this system are currently administered by ADEM under the RCRA
Part B Permit. Semi-annual sampling results are reported to ADEM annually and show
that the groundwater corrective action system has effectively reduced the extent of the
plume for indicator parameters (mercury, chloroform, and 1,4-dichlorobenzene) and
halted migration of groundwater COCs.
Olin also installed a multi-layer cap over the former CPC landfill, implemented
institutional controls, and prepared/implemented monitoring plans at OU-1 as part of the
1995 CD. These measures were performed to further control potential source areas and
reduce risk to human health and environment.
In 2001, restrictive covenants were placed on the OU-1 Site property, which were
designed to prevent exposure to soil and groundwater contamination. One of the
restrictive covenants prohibits the use of groundwater from the remediated portion of
the alluvial aquifer as a source for potable water. In addition, the second restrictive
covenant prohibits the use of remediated surfaces in OU-1 for uses other than approved
industrial uses to prevent exposure to contaminated soil.
The construction necessary for the OU-1 cleanup plan began in 2000 and was
completed in 2001. The plan was implemented in 2000 and 2001. A 2006 assessment
found that the cleanup plan was implemented properly. Closure of SWMUs,
implementation of the OU-1 groundwater recovery and treatment system, and
installation of a multi-layer cap at the former CPC landfill serve as early source control
measures for the Olin Mcintosh facility.
The Mcintosh plant today produces chlorine, caustic soda, sodium hypochlorite and
sodium chloride and blends and stores hydrazine compounds. Current active facilities at
the plant include: a diaphragm cell chlorine and caustic production process area; a
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caustic plant salt process area; a hydrazine blending process area; shipping and
transport facilities; process water storage, transport and treatment facilities; and support
and office areas. Olin mines a salt dome through a series of brine production wells
located to the west of the active plant facility. The salt dome cap rock is at a depth of
approximately 500 feet below the surface, and the dome is approximately 4,500 feet in
diameter and greater than 2 miles deep.
Nine brine wells have been completed in the salt dome for the production of brine. The
first six wells were associated with the mercury cell chlor-alkali plant and are no longer
in service. The other three brine production wells were developed in a different portion
of the salt dome, have been used exclusively for the diaphragm cell plant, and are still in
use. A tenth cavity was developed in the dome by Olin for use by the Alabama Electric
Cooperative to store high-pressure air for off-peak power production.
The Olin Mcintosh plant currently monitors and reports on numerous facilities within the
plant that are permitted through the EPA and ADEM. These include water and air
permits as wells as a RCRA post-closure permit. The RCRA post-closure permit
requires groundwater monitoring for closed RCRA units, including the weak brine pond,
the stormwater pond and the brine filter backwash pond. The post-closure permit also
requires corrective action for releases of 40 CFR 261 (Appendix VIII) constituents from
any SWMUs at the facility. There are no active RCRA units at the facility. Olin also has
permits for three injection wells for mining salt and a neutralization/percolation field.
The plant wastewater ditch currently carries the National Pollutant Discharge
Elimination System (NPDES) discharge and storm water runoff from the manufacturing
areas of Olin property to the Tombigbee River. From 1952 to 1974, plant wastewater
discharge was routed through the Basin and then to the Tombigbee River. In 1974, Olin
ceased discharge of process waters from their mercury-cell chlor alkali and CPC
facilities to the Basin. A discharge ditch was constructed to reroute the wastewater
directly to the Tombigbee River. Two of the three COCs, mercury and HCB, are
associated with this former discharge.
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The third COC, Dichlorodiphenyltrichloroethane (DDT) along with its metabolites (DDD
and DDE), is likely the result of indirect discharges from a Superfund Site located
immediately north of OU-2. Ciba-Geigy (currently owned by BASF) manufactured DDT
at this Superfund Site beginning in 1952. DDT manufacturing ceased in the 1960s. This
ROD uses the term DDTR to refer to the collective sum of the 2,4'- and 4,4'- isomers of
DDT, DDE, and DDD. The term DDTr refers to the sum of only the 4,4'- isomers of
DDT, DDE, and DDD.
The COCs were deposited in the Basin, Round Pond, wastewater ditches and
surrounding floodplains. The deposition pattern of the chemicals was influenced by
wastewater discharges, Basin bathymetry, floods, water level conditions, wind effects
and geochemical and physical parameters.
2.3 COMMUNITY PARTICIPATION
Under the NCP at 40 CFR 300.430(c), Olin participated in the EPA's community
involvement plan. In accordance with this plan, initial community outreach and public
meetings have been conducted where information has been presented collectively
regarding planned and on-going studies and projects. A Technical Advisory Group
(TAG) grant was awarded to the Mcintosh Environmental Concerns Committee on
February 15, 1993. The EPA attended the yearly meetings held by the TAG Advisor in
the 1990s. The last formal contact the EPA had with the concerned citizen group was in
2003. The Olin Corporation also has a Community Advisory Group for the Mcintosh
Plant.
In March 2005, a civil lawsuit was filed against the Olin Corporation. The lawsuit alleged
that releases of mercury from the Olin facility contaminated homes and property of their
clients. Based upon the law firm's sampling in the community, the lawsuit alleged that
mercury contamination from Olin was wide spread in Mcintosh; therefore, Plaintiffs were
seeking "class action status" to bring an additional 2000 clients into the case. The court
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denied the class action status request.
The local newspaper has written many articles on mercury contamination in Mcintosh.
Allegations of mercury contamination in the community have made the citizens
concerned about their health and the quality of the local environment. Responding to
the community's concerns, ADEM conducted environmental sampling on and off the
Olin facility property. This action was taken in consultation with the Alabama
Department of Public Health and the EPA. A public meeting was held in 2005 to present
the results of the sampling and to assure residents that there is not a significant mercury
health risk to the community from the Site.
As part of ongoing Five Year Reviews of Olin's OU-1 remedy and BASF's remedy, the
EPA and ADEM have also communicated regularly with the public.
As part of the OU-2 community outreach, the EPA conducted community interviews in
the fall of 2012 and attended a town hall meeting in February 2013. The EPA engaged
the local stakeholders to determine what environmental issues concerned most citizens.
The Community Involvement Coordinator is in the process of updating the 1991
community involvement plan.
In the February 12, 2013 town hall meeting, the EPA presented the schedule for the
upcoming Proposed Plan and a brief description of the proposed remedy. One of the
concerns citizens wanted addressed was that the Tombigbee River had no fish advisory
signage at any of the boat ramps used by the local community. In response, EPA
contacted the State of Alabama to find out how the Health Department addresses fish
advisories. The EPA was informed that due to budgetary constraints, the State does not
place signage out for fish consumption advisories. This information is maintained on the
Alabama Department of Public Health website
(http://www.adph.org/tox/index.asp?ID=1360). According to the State official, if the
citizens would like fish advisory signage, the town would have to incur that cost. The
EPA has contacted the town council and concerned citizens and shared this information
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with them. The EPA is including the need for signage as part of the selected remedy.
In addition, a Proposed Plan was developed for the local community describing on-
going projects and activities. A public meeting to present the Proposed Plan for the Olin-
Mclntosh Site was held on May 22, 2013. The EPA and ADEM were present to address
the State and Public Health agency perspectives on the proposed remedies for the Site.
A public comment period was open from May 22, 2013 to June 21, 2013. The EPA's
response to the comments received during this period is included in the
Responsiveness Summary, which is part of this Record of Decision.
Site documents are available to the public in the administrative record repositories
located at the EPA Region 4 Superfund Records Center (61 Forsyth Street, Atlanta, GA
30303) and these documents are also posted on the EPA Region 4 webpage
(http://www.epa.gov/region4/foiapgs/readingroom/index.htm). The EPA Region 4's local
repository is located at the Mcintosh Volunteer Fire Department Building (206
Commerce Street, Mcintosh, AL 36553).
2.4 SCOPE AND ROLE OF OPERABLE UNIT OR RESPONSE ACTION
The Rl and the FS reports were submitted in July 1993 and February 1994,
respectively. The reports were approved for OU-1 only. As with many Superfund sites,
the contamination problems at the Olin Site are complex. As a result, the EPA
organized the work into operable units (OUs):
• Operable Unit 1 (OU-1): the active production facility, SWMUs, and groundwater
contamination in the upland area;
• Operable Unit 2 (OU-2): the Olin Basin located adjacent to the Tombigbee River,
the surrounding floodplain and a wastewater ditch leading to the Basin.
OU-1 and OU-2 are depicted in Figure 2.
The Record of Decision (ROD) detailing the cleanup plan for OU-1 was issued on
December 16, 1994. It addresses the source of the contamination on the Site as well as
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the ground water contamination across the entire Site. The major components of the
cleanup approach taken include:
• Installation of additional wells to remove and treat contaminated ground water.
• Upgrading the existing cap, or cover, over the CPC landfill with a multimedia cap.
• Extending the clay cap that exists over the former CPC plant to an area west of
the former plant.
• Conducting additional ground water monitoring in the vicinity of the sanitary
landfills.
• Analyzing the long term effectiveness of the ground water treatment in reducing
ground water contaminant migration.
• Implementation of institutional controls for land and ground water use restrictions.
The ROD for OU-1 also indicated that a ROD for OU-2 would be developed if it is
determined that cleanup action for OU-2 is necessary.
This ROD for the second operable unit (OU-2), addresses contamination in a lake,
referred to as the Olin Basin, Round Pond, the floodplain adjacent to the Tombigbee
River, and in a wastewater ditch that flows toward the lake and the River. Since the
Olin Basin is located on private property and fenced, the Basin, which is considered
waters of the State of Alabama, is not easily accessible to the public. The potential
future scenario of unrestricted use results in an unacceptable risk to human health. The
risk was driven by ingestion of mercury contaminated fish caught from OU-2, with
minimal contribution from dermal contact with surface water and soil, and inhalation of
particulates. The ecological risk assessment determined that the most significant
potential exposure pathways were direct contact and food chain uptake of mercury and
DDTR by fish; ingestion of mercury and DDTR contaminated fish by avian receptors;
and incidental ingestion of HCB contaminated sediment by piscivorous mammals.
This OU-2 ROD presents the final response action for this Site.
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2.5 SITE CHARACTERISTICS
2.5.1 Site Setting
Washington County is part of the Southern Pine Hills District of the East Gulf Coastal
Plain Physiographic Province. OU-2 lies in the Alluvial-deltaic Plain, which consists of
sediment deposits associated with larger rivers. The climate in this area is humid
subtropical, with relatively mild winters. Rainfall in southern Alabama is relatively evenly
distributed throughout the year. Frost and especially snow seldom occur. According to
the National Weather Service (NWS) regional report (1971-2000), the region has an
average annual precipitation of 66.62 inches, and an average annual temperature is
67.4 degrees Fahrenheit (°F), with July having the highest monthly average (82.1°F)
and January having the lowest monthly average (50.7°F). The National Climatic Data
Center reported an average annual precipitation of 66.3 inches from 1990 to 2009 in
Mcintosh, Alabama. Winds are variable throughout the year, but there are general
seasonal patterns. Winds are mainly from the south or southeast from March through
August; winds tend to be from the north during the remainder of the year.
OU-2 surface water quality is typical of southern freshwater lakes—pH is circum neutral,
water temperatures follow seasonal trends and decrease with depth, DO decreases with
depth, and oxic conditions in surface water are present throughout most of the year.
There is evidence of thermal stratification in the deeper portion of the Basin in late
summer. Turbidity is generally less than 15 NTUs throughout the water column during
non-flood conditions, except within a foot of the surface water sediment interface where
turbidity increases to 50-60 NTUs.
2.5.1.1 Surface Water Features
The permanent water bodies of OU-2 are interpreted as "oxbow-like" features; i.e.,
vestiges of an abandoned Tombigbee River channel. The Basin and Round Pond cover
approximately 76 and 4 acres, respectively, at a normal (nonflooded) stage. Although
interpreted as an "oxbow-like" feature, OU-2 has a depression, with depths of nearly 40
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feet in the northwest quadrant of the lake. The OU-2 Basin is adjacent to Tombigbee
River Mile (TRM) 60.4 and was evidently semi-isolated from the river at least a few
centuries ago. The OU-2 Basin is located between a bluff to the west and the
Tombigbee River (the river) to the east. The bluff is approximately 30 to 35 feet above
the Basin water level at a non-flood elevation of 3 feet North American Vertical Datum
1988 (NAVD88).
Round Pond drains via a direct channel into the Basin. The Basin has a surface area
of about 76 acres at normal (nonflooded) stage. Cypress Swamp is the smallest and
shallowest of the three water bodies; Round Pond is slightly larger and deeper; and the
Basin is the largest and deepest feature.
Prior to construction of the Olin facility, a natural drainage feature carried runoff from the
upland areas into the Basin. This drainage feature became the wastewater ditch when
the Olin facility was constructed. Prior to 1968, the wastewater flowing from the ditch
into the Olin Basin contained releases of lime used to remove chlorine from tailgas (or
off-gas) from the chlorine liquefaction process. Later, lime and sulfate were used to
neutralize the acidic wastes before they were discharged to the wastewater ditch.
Wastewater was discharged through this ditch to the Basin until 1974, leaving
concentrations of mercury and HCB in the ditch and Basin sediments and adjacent
soils. Steps were taken in 1974 to insure that the wastewater did not "back up" into the
Basin during water fluctuations of the Tombigbee River. First, the natural low-lying area
south of the Basin was deepened to form the last section of the current wastewater
ditch. Second, a sheet pile dam was installed across the Basin outlet. The sheet pile
weir was constructed to keep the wastewater stream from discharging into the Basin
during periods of low river stages. Third, a small berm was extended around the south
and east bank of the Basin to minimize overflow from the river into the Basin during
normal water levels. This third step resulted in an excavation feature. A berm was
created by excavating and piling soil along the route of the berm. Since 1974, the
wastewater ditch has carried Olin's permitted wastewater discharge to the Tombigbee
River.
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During seasonal high water levels (averaging 4-6 months per year), the Basin and
wetland areas are inundated, becoming contiguous with the adjacent Tombigee River.
Prior to 2006, the OU-2 water bodies exchanged water and sediment with the river
during flood events when water surface elevations (WSE) exceeded 4 feet.
Construction of a berm and gate system around the Basin was initiated by Olin in June
2006 as part of their Enhanced Sedimentation Pilot Project (ESPP). The berm was
constructed to an elevation of approximately 12.0 feet around the Basin and some of
the floodplain, with a gated structure built on the southern end of the Basin to control
flows in and out of the Basin. The intent of the berm and gate system was to enhance
the capture of sediment-laden floodwater by increasing the holding time of floodwaters
within OU-2, allowing incoming sediment to be deposited therein.
There is typically little or no flow from the Basin to the river or vice versa during non-
flood conditions, when the water elevation in the river is approximately 3 feet NAVD88
(or less). At a river WSE of approximately 4.0 feet, river water and sediment flow into
the Basin through the gated structure. The Basin and floodplain will eventually fill, with
the berms overtopped at a river WSE elevation of 12.0 ft. However, at a river WSE of
approximately 10 feet, the Tombigbee River begins to flow into the northernmost
floodplain above the Basin, including the adjacent BASF property. Also, at a WSE range
of 10 — 12 feet, floodwater is entering the Site from the southernmost connecting
channel while the northernmost floodplains are flooding on the river side of the berm.
The river water flowing through the floodplains is circulating outside the berm, and
returning to the river through a ditch that runs from the BASF property through the Olin
property and eventually to the river.
At a river WSE greater than 12 feet, the berms are overtopped, and the Basin, Round
Pond and floodplains are inundated and become contiquous with the river. During the
ESSP evaluation period, when the flood receded to the top of the berm (WSE of 12
feet), the gate was closed on the connecting channel, and the water was held in the
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Basin in an effort to allow suspended sediment to settle out. At that time, the water was
released back to the river. For smaller floods for which the WSE did not exceed 12 feet,
the gate was closed at the peak of the flood in an effort to trap any sediment that may
enter the system through the gate.
Based on analysis of 2008 and 2009 data, the EPA determined that the ESSP
contributed very small amounts of river sediment to the Basin. The Basin was provided
insufficient sedimentation to effectively cap the Basin and would not be considered as a
stand-alone remedy for the Olin OU-2 Superfund Site.
In 2009, Olin decided to operate the berm and gate system to maintain a minimum
water depth with a WSE of 6 feet NAVD88 to help reduce the potential for wind-driven
resuspension. The inundated area of OU-2 when the water is held at 6 feet NAVD88 is
approximately 135 acres, while the area contained within the berm is approximately 156
acres. The 2006 bathymetric study of the area is presented in Figure 3.
A continuously recording data logger with transducers on both the Basin and river sides
of the gate maintains a record of water elevations at OU-2. Staff gauges are located on
both the Basin and river sides of the gate, and an additional staff gauge is located on
the berm to record water elevations above 12-feet NAVD88. The equation relating water
levels at the USGS Leroy gauge (02470050) and Mcintosh can be used to estimate
water levels at the intake channel when an 18-to 24-hour lag time is considered.
Some areas of the Basin, such as the deeper portion and the southern portion,
experience more deposition than other areas. Sediment in the northern and central
portions of the Basin and Round Pond consists of silts and clays and have total organic
carbon (TOC) greater than 10,000 mg/kg. Sediment in the southern portion of the Basin
has a sand component and TOC generally less than 10,000 mg/kg. Sediment pH is
generally circumneutral and oxidation-reduction potential (ORP) indicates reducing
conditions.
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2.5.1.2 Geology/Hydrogeology
The Basin and Round Pond lie within the floodplain of the Tombigbee River. Alluvial
deposits of unspecified ages are present from the land surface of OU-2 to a depth of
approximately 20 to 30 feet. These deposits consist of reworked and redeposited
sediments along with river-transported sediment. The sediments consist of interlayered
sands, silty or clayey sands, silts, and clays. These sediments represent numerous
depositional environments including natural levees, bars, infilled channels, channel
deposits, flood-splays, and other deposits associated with meandering rivers. Cores
collected within the Basin and Round Pond, including the deepest portion of the Basin,
indicated the presence of predominantly clay riverine deposits beneath the Basin and
Round Pond. Geologic conditions based on hydrogeologic investigations at OU-2 are
conceptualized in cross-section Figures 4, 5 and 6 and are described in the following
paragraphs.
Based upon elevation data collected in the 2008 and 2009 investigations, the Miocene
clay layer apparently dips to the west-southwest at about 32 feet per mile. An
undetermined thickness of Miocene clay was most likely eroded from the bottom of the
Basin (Figure 6). A brief description of these alluvial deposits, from the most recent to
the oldest, and a hydrogeologic description is provided below.
Riverine deposits (R) are flood deposits from the Tombigbee River. These deposits are
near the Basin and Round Pond and are typically composed of tan, black, and dark gray
silty clays and clayey silts that are interspersed with fine, medium, and coarse-grained
sands. These sediments are underlain by greenish brown, brown, grey, and black clay;
organic silty clay; and clayey sand deposits that are interpreted to be floodplain
deposits. They vary in thickness from approximately 13 feet to 23 feet and are
unconfined. Groundwater flow appears to be to the southeast, based on a Basin surface
elevation of 2.9 feet.
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The bluff to the west of OU-2 is approximately 20 to 30 feet higher in elevation than the
floodplain. Previous investigations indicated that the Upper Clay Unit at the Alluvial
Sediment (Q1) west of OU-2 primarily consists of silty/sandy plastic clay (WCC, 1993).
Q1 sediments were observed immediately west of the bluff in OU-1 at a thickness
ranging from 10 to 20 feet. These sediments were composed of sandy clay, low
plasticity clay, and clayey sand.
The Alluvial Aquifer system of the Quaternary Alluvial Sediment (Q2) varies in thickness
from approximately 37 feet in the west plant area to 60 feet in OU-1. East of the bluff,
Q2 averages about 40 feet thick and typically grades downward from fine sands to
coarse-grained sands with some gravel in OU-2. Q2 is divided into two zones, an upper
zone and a lower zone, and is generally unconfined near the Basin. Groundwater flow is
generally to the southeast.
The upper zone of Q2 is composed primarily of very fine to fine-grained silty quartzose,
subangular to subround sand. The lower zone of Q2 is composed of fine to very coarse,
orange-brown, quartzose, cherty, subangular to subrounded sands containing varying
amounts of gravel. Although composed predominantly of sands, Q2 also contains some
thin beds of clay or silty, gravelly clay.
To the north, south, and east of the Basin it appears that Q1 and the upper zone of Q2
have been eroded by the Tombigbee River and are not present, but the lower zone of
Q2 is present.
The bottom elevation of the Basin ranges from approximately 2 to -36 feet NAVD88.
Shallow areas (2 to -4 feet NAVD88) are located in the southern portion of the Basin.
The deepest part of the Basin is in the northwest. Floodplains are located to the north,
northeast, and east of the Basin. The Basin is underlain by R, followed by the alluvial
sediments of the lower zone of Q2; therefore, the Basin is in direct hydraulic connection
with R.
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The Miocene Confining Unit (Tm1) underlies Q2. This unit consists of clays, sandy
clays, or clayey sands. Although the lithology may be complex, it is predominantly clay,
with various amounts of discontinuous sand, silt, or fine gravel. Boring logs from wells
that penetrate Tm1 indicate that this unit is laterally continuous beneath OU-1 and
approximately 80 to 100 feet thick in the plant areas west of OU-2. At OU-2, Tm1,
consisting of a low-plasticity clay, was found along the bluff at depths ranging from 55 to
65 feet below land surface. Just above the clay unit, a 10- to 15-foot layer of coarse
sand and gravel was present and served as a marker for the approaching Tm1 unit.
Along the southern berm, the top of Tm1 was not always encountered. Where Tm1 was
not encountered, a layer of well-graded gravel underlain by poorly graded fine sand was
used as a marker bed for approaching the top of Tm1. This gravel layer was
encountered at depths ranging from 39 to 42 feet below the top of the berm.
Tm1 is underlain by the Miocene Aquifer. The Miocene Aquifer is composed primarily of
thick-bedded, coarse sand and gravel beds; however, sandy clay lenses occur within
this unit. The attitude of the upper boundary of this aquifer is nearly horizontal in the
main plant area; however, in the west plant area there is a pronounced southeastward
dip, from -114 to -166 feet NAVD88 at OU-1. These differences are interpreted to be
related to structural deformation of sediments associated with an underlying salt dome.
The Miocene Aquifer was not encountered during the OU-2 investigation.
Movement of groundwater at the Olin Site is controlled by hydraulic gradients, porosity,
permeability, and continuity of water bearing sediments. The Miocene clay is 55 to 65
feet thick along the bluff at OU-2 and is generally characterized as a continuous
confining unit, preventing downward movement of water and contaminants from
overlying alluvial sediments into the underlying Miocene aquifer. The dominance of fine-
grained sediments encountered in the upper parts of all piezometers and micro-wells
constructed in 2008 suggests limited surface-water/groundwater interaction and
restricted local vertical movement of groundwater. The juxtaposition of deeper, coarse-
grained sediments described earlier, creates pathways for horizontal groundwater
movement from the bluff to the floodplain.
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The evaluation of potentiometric surface maps constructed from groundwater levels
indicates a relatively steep hydraulic gradient from the bluff to the floodplain and a
relatively low gradient from the floodplain to the Tombigbee River. The berm between
the Basin and the river restricts groundwater movement and the inlet channel
connecting the Basin with the river acts as a groundwater sink, which captures and
directs groundwater to the Tombigbee River. Although the general characterization of
the hydraulic gradient between the berm and the Tombigbee River as an "area of little
gradient" is correct, it is important to note there is probably a hydraulic connection
between the river and floodplain in the vicinity of micro-wells BA-MW6 and BA-MW7
(Figure 7).
2.5.2 Conceptual Site Model
Information on primary sources of contaminants, chemical release mechanisms,
transport media, potential receptors, exposure routes and subsequent complete
exposure pathways for Site contaminants at OU-2 are combined to provide a pathway
analysis for the Site which is termed the Conceptual Site Model (CSM). The CSM has
been refined from the 1991 model. Additional information and data developed between
2006 and 2009 have been used in updating the CSM (Figure 8). This figure indicates
potential complete and incomplete pathways. Complete pathways are designated by a
closed or open circle. Empty boxes are incomplete pathways or considered to contribute
negligible exposure. Exposure routes that were not evaluated are designated by an X.
Only complete exposure pathways were addressed in the risk assessment.
The primary constituent of concern (COC) at OU-2 is mercury, which best represents
the extent of contamination in sediments and biota in the Basin and Round Pond. The
other COCs are HCB and DDTR.
The fate and transport of COCs within the Olin Basin is a complex subject influenced by
the hydrology and bathymetry of the Basin, as well as a variety of geochemical and
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geophysical parameters. Fate and transport of HCB and DDTR are relatively more
straightforward than that for mercury, due to the unique biogeochemistry of mercury in
aquatic environments.
The primary release mechanism for HCB to OU-2 was the discharge through the former
wastewater ditch from 1952 to 1974. The wastewater ditch runs from the plant area in
OU-1 to an area south of the Basin. Runoff and treated wastewater from the plant were
not discharged to the Basin after 1974. The plant effluent and stormwater discharge are
permitted and monitored under the NPDES. Current monitoring data show that the plant
effluent and stormwater discharge meet the limits contained in the NPDES permit.
The wastewater ditch and former discharge ditch were investigated during the initial Rl
sampling activities in 1991/1992 and again in 2001. The highest concentrations of HCB
remain in the southern third of the Basin, particularly around the historic discharge
channel and the current outflow channel to the Tombigbee River.
DDTR entered OU-2 from the adjacent BASF property to the north. DDTR
concentrations decline from north to south, with highest concentrations being in the
wetland soils north of the OU-2 Basin. High concentrations were also found in the Basin
deep hole subsurface sediment at a depth of 4-6 feet below the sediment surface.
DDTR has low solubility and high affinity for organic matter, thus transport in aquatic
systems is generally in the form of resuspension and redistribution of particle bound
DDTR. DDTR is highly lipophilic, resulting in biomagnifications up the food chain.
Currently there is some uncertainty associated with the magnitude and extent of DDTR
concentrations in the wetland area northwest of the OU-2 Basin. Supplemental
sampling of this area to delineate the extent of DDTR will be performed as part of the
remedial design for OU-2.
Mercury entered the Basin from the wastewater discharge channel in the southwest
corner of the Basin and was discharged from 1952 to 1974. Mercury was discharged in
the form of mercury salts. The highest mercury concentrations in surface and near-
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surface sediment currently occur in a band that runs from the southwest corner of the
Basin near the historic discharge point to the northeast corner of the Basin. This pattern
of distribution has persisted since the earliest sediment sampling event in 1991.
Sampling of geochemical parameters has shown that the northern and western portions
of the Basin are characterized by relatively high sulfide and high TOC concentrations,
while the southern and eastern portions are characterized by low sulfide and low TOC.
Data suggest mercury is not as strongly bound to TOC and AVS in the northern Basin
as one would expect, given levels of sulfide and TOC present in the northern Basin.
These geochemical parameters are not conducive to formation of stable mercury
compounds, but rather these parameters indicate release and mobilization of mercury.
Available data suggest that mercury is relatively mobile within the Olin Basin under
current conditions, while HCB and DDTR are relatively immobile in OU-2 sediments.
The focusing of mercury in the Basin sediments suggests mobility of mercury with
settling out where conditions favor binding to sediments or precipitation. Available data
do not make it clear which chemical properties are controlling this focusing, but any
remedial design for mercury in the OU-2 Basin should design for reasonable maximum
mobility as if contaminant mobility can occur anywhere within the Basin.
Numerous studies and investigations have been conducted at OU-2 since the 1980s.
These studies have been grouped into two categories. Results from studies conducted
from the 1980s to 2002 are considered historical. Reports on these historical studies
include:
• Remedial Investigation Report (WCC, 1993)
• Additional Ecological Studies of OU-2, Volumes 1 and 2 (WCC, 1994)
• Ecological Risk Assessment of Operable Unit 2 (WCC, 1995)
• Feasibility Study Operable Unit 2 (WCC, 1996)
• OU-2 RGO Support Sampling Report (URS Corporation [URS], 2002)
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Results from studies conducted immediately before the construction of the berm and gate
system are considered recent. Reports on these studies include:
• Remedial Investigation Report (WCC, 1993)
• Additional Ecological Studies of OU-2, Volumes 1 and 2 (WCC, 1994)
• Ecological Risk Assessment of Operable Unit 2 (ERA) (WCC, 1995)
• Feasibility Study Operable Unit 2 (WCC, 1996)
• OU-2 RGO Support Sampling Report (URS Corporation [URS], 2002)
• Enhanced Sedimentation Pilot Project (ESPP) Baseline Sampling (baseline report)
(MACTEC Engineering and Consulting, Inc. [MACTEC], 2007)
• Enhanced Sedimentation Pilot Project Annual Report - Year 1 Results (Year 1
Report) (MACTEC, 2009a)
• Remedial Technologies Screening and Alternatives Development in Support of a
Feasibility Study (MACTEC, 2009b)
• Part 1 - Revised Remedial Investigation Addendum and Enhanced Sedimentation
Pilot Project Annual Report, Year 2 Results, Operable Unit 2 (AMEC, 2011 a)
• Part 2 - Updated Ecological Risk Assessment, Operable Unit 2 (AMEC 2011 b)
• Part 3 - Updated Human Health Risk Assessment (AMEC, 2011 c)
• Remedial Goal Option Report for the Development of Preliminary Remediation
Goals in Sediment and Flood plain Soils, Revision 3 (AMEC, 2012a)
• Feasibility Study, Revision 3, Operable Unit 2, Mcintosh, Alabama (AMEC, 2012b)
The data matrix table (Table 1) provides an explanation of how the historical and recent
data were used in the remedial process. Historical results for surface water, sediment,
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and soil are summarized in Table 2. Recent data collections are presented in the
following section.
2.5.3 Nature and Extent of Contamination
2.5.3.1 Groundwater
A groundwater investigation of OU-2 was performed to determine whether the OU-2
sediments act as a continuing source of contamination to groundwater and ultimately
effect surrounding water bodies, in particular the river.
Seventeen micro-wells were installed in 2008, at eight locations around the Basin for
groundwater collection and analysis. Micro-well BA-MW1 in OU-1 serves as an
upgradient well to the Basin during non-flood or baseline conditions. The remaining
wells are located within OU-2. The OU-2 wells were spaced approximately 500 to 700
feet apart along the berm (Figure 7). The micro-wells were generally positioned at
locations thought to be potentially hydraulically downgradient and sidegradient from the
largest area of higher mercury concentrations in the Basin sediments. The screens for
the micro-wells were installed in the lithologic units of Riverine Deposits (R) and Alluvial
Aquifer of the Alluvial Sediments (Q2). The micro-wells were installed in clusters of two
or three so that water quality parameters could be collected at shallow and intermediate
depths from R and Q2, respectively. Well depth varied based on location because of the
variation in unit depth throughout the Site.
Filtered (0.45 |jm membrane filter) mercury was not detected above of 0.0012 |jg/L [the
ADEM fresh water quality criteria (WQC) for protection of aquatic life] in the
groundwater samples. Though the ADEM WQC are intended for surface waters, they
were used as a point of comparison here to determine if groundwater represents a
potential source to surface water at concentrations that exceed levels of concern. Based
on concentrations of mercury in groundwater at MW-2, MW-3, MW-4 which are between
the Basin and the river, groundwater is not a source of mercury to the river at levels of
concern.
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DDTR was not detected above the reporting or method detection limits (0.023-0.026
|jg/L) in the groundwater samples. The ADEM aquatic life WQC for 4,4' - DDT is 0.001
|jg/L. The human health WQC for consumption offish only for DDTR is 0.0002 |jg/L.
HCB was detected in one micro-well above the reporting limit of 0.010 |jg/L with
concentrations of 0.011 to 0.013 |jg/L. The ADEM WQC for HCB is 0.0002 |jg/L. One-
dimensional fate and transport model results indicate that the HCB concentrations
detected in OU-2 would not result in an exceedance of the HCB surface water quality
criteria in the Tombigbee River.
The 2009 sediment core results from the Basin, with the exception of SCDR-08, indicate
that mercury in sediment in the Basin is not a continuing source to groundwater or the
river via the groundwater pathway. The sediment core results are more fully discussed
in Section 2.5.3.3. It is important to note that the core from the deep hole, SDCR-08 as
depicted in Figure 9, did not fully bound the vertical extent of contamination, but the
monitoring wells do suggest that mercury, DDTR, or HCB in deep sediments is not a
continuing source to the river. Continued monitoring of groundwater will be included in
the remedial process.
Groundwater beneath the Basin may contact and seep upward through the clay-rich
sediments. Additional evaluation is needed to estimate the groundwater seepage
velocity as part of the remedial design.
2.5.3.2 Floodplain Soil
The analytical results for floodplain soil parameters, including mercury, methylmercury,
HCB, and DDTR, are summarized below. Individual results are shown on Figures 10
through 13 and are provided in Table 3. Floodplain soil results for COCs were reported
in dry weight. Three of the surficial floodplain soil locations were inundated at the time of
sample collection. These locations, FPSS3, FPSS9, and FPSS15, may be considered
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sediment when the water elevation is maintained at a minimum of 6 feet NAVD88.
Soils in the floodplain consisted of 73 to 95 percent silts and clays, with 3 to 25 percent
sand and 0.06 to 2.5 percent gravel. The sand and gravel portions were higher in the
southern portion of the floodplain and decreased moving north. Percentage solids of the
surficial soils ranged from 48.0 to 78.3 percent, and percentage solids for the inundated
(covered with water at the time of sampling) soil samples ranged from 15.1 to 28.7
percent. Total organic carbon (TOC) content in surficial soils ranged from 15,900
milligram per kilogram (mg/kg) to 61,700 mg/kg. TOC concentrations decreased with
depth in soil borings. TOC for the three inundated soil samples ranged from 33,700
mg/kg to 298,000 mg/kg. These values are typical of floodplain forested wetlands.
Concentrations of mercury in surficial floodplain soils are shown on Figure 10. The
minimum mercury concentration in surficial soil was 0.061 mg/kg at FPSB4 located east
of the Basin, and the maximum mercury concentration was 8.9 mg/kg at FPSS2 next to
the channel connecting the Basin and Round Pond. The range of mercury
concentrations in surficial floodplain soils excluding the maximum value was 0.061
mg/kg to 2.5 mg/kg, with an average of 0.814 mg/kg. The maximum value of 8.9 mg/kg
was likely representative of sediment/soils near the channel connecting Round Pond
and the Basin. The concentrations of mercury at the three inundated sampling locations
were within the range of concentrations of non-inundated floodplain soils.
Mercury concentrations in surficial floodplain soils generally decreased with increasing
distance from the water's edge of the Basin and Round Pond.
Mercury concentrations in the soil borings were generally less than 1 mg/kg with small
increases or decreases with depth. The exception was FPSB5, which was near the
southeastern Basin edge. Concentrations at this location ranged from 2.4 mg/kg at the
surface (0 to 1 inch) to 3.6 mg/kg (6 to 12 inches) at depth.
Methylmercury concentrations in surficial floodplain soils (0 to 1 inch deep) averaged
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0.00303 mg/kg and ranged from 0.000367 mg/kg at FPSB4 to 0.00703 mg/kg at FPSB5
(Figure 11). The percentage of mercury that was methylmercury in surficial floodplain
soils ranged from 0.123 percent at FPSB6 (southeast of the Basin) to 1.29 percent at
FPSB3 (northeast of the Basin). Methylmercury concentrations from 1 to 2 inches deep
ranged from 0.000176 JB mg/kg at FPSB6 to 0.00822 mg/kg at FPSB5. The percentage
of mercury that was methylmercury in 1 to 2 inch soils ranged from 0.126 percent at
FPSB6 to 1.19 percent at FPSB3. The floodplain at OU-2 is bottomland hardwood
forest, a type of wetland. Wetlands have saturated soils, and saturated soils are
anaerobic because water from the capillary fringe forces oxygen out of the soil.
Methylmercury that was formed in the floodplain soils while inundated will likely remain
for some time after flood waters recede because of the hydric, anaerobic conditions of
the soil.
HCB was collected in surficial soils (0 to 1 inch deep) from three locations in the
southern portion of the floodplain as shown on Figure 12. Concentrations ranged from
0.0035 mg/kg at FPSB5 in the southeastern floodplain to 0.275 J mg/kg at FPSS14 in
the southwestern floodplain. Location FPSS15 was inundated and had a concentration
of 0.135 mg/kg.
DDTR was collected from 15 locations throughout the floodplain (Figure 13). The results
for the six analyzed congeners were summed to obtain the DDTR value listed on Figure
13. Zero was used in the summations for congeners that were not detected at the
associated reporting limit for the sample. DDTR concentrations in surficial floodplain
soils ranged from < 0.002 UJ mg/kg (FPSB6) in the southeast portion of the floodplains
to 2.23 mg/kg (FPSS1) in the northwest portion of the floodplain. To evaluate
uncertainty in DDTR resulting from non-detected congeners, DDTR was recalculated
using one-half the reporting limit for non-detected concentrations. These summations
only effected the lower end of the concentration range, and resulted in concentrations
ranging from 0.0038 JQ mg/kg (FPSS10) to 2.23 mg/kg (FPSS1). DDTR concentrations
decreased from north to south, with the highest concentrations measured in the
northwest portion of the floodplain.
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DDTR concentrations in the northwest were two to three orders of magnitude higher
than those in the eastern and southern portions of the floodplain.
2.5.3.3 Sediment
Surficial Sediment
In 2009, sediment samples were collected along 6 east-west transects. Average
surficial sediment mercury concentrations by transect in the Basin ranged from 13.8
mg/kg to 57.0 mg/kg in 2009. The lowest mercury concentration, 2.01 mg/kg, was
collected in the southern portion of the Basin and the highest mercury concentration,
116 mg/kg, was collected in the central transect within the Basin. Average mercury
concentrations were generally higher in the central portion of the Basin. Round Pond
mercury concentrations ranged between 14.1 mg/kg and 32.1 mg/kg, with an average
mercury concentration of 21.5 mg/kg, as shown on Figure 14, which shows the
distribution of mercury in surficial sediment using isoconcentration contours. The 2009
data are referenced here because these data are the most comprehensive data set,
including fine and coarse coring analyses. The range of mercury concentrations
detected in 2006 was 6.45 to 95.3 mg/kg; mercury concentrations in 2008 ranged from
0.965 to 213 mg/kg. The range of mercury concentrations in historical sampling events
(defined as prior to 2001) was non-detect (detection limit of 0.19 mg/kg) to 290 mg/kg in
1991, 18.6 to 113 mg/kg in 1994, and 0.844 to 780 mg/kg in 1995.
Average surficial sediment methylmercury concentrations by transect in the Basin
ranged between 0.00431 mg/kg and 0.0115 mg/kg in 2009. Methylmercury
concentrations ranged from 0.00142 mg/kg, in the southernmost transect, to 0.0257
mg/kg, in the north-central transect. Figure 15 depicts the methylmercury results and
distribution in sediment for 2009. Round Pond methylmercury concentrations
ranged between 0.00451 mg/kg and 0.00640 mg/kg, with an average concentration of
0.00562 mg/kg.
HCB and DDTR were also identified as COCs for OU-2. A summary of HCB and DDTR
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concentrations and ranges by transect is provided in Table 4. Sediment HCB
concentrations ranged from non-detect at a reporting limit of 0.0069 mg/kg to 8.90
mg/kg in 2009. The maximum HCB concentration was reported in the southern portion
of the Basin, approximately 200 feet northeast of the inlet channel.
Samples collected north of the gate structure in 2009 indicated an order of magnitude
decrease in HCB from 1991 and 1994, in which the concentration range was non-detect
(0.67 mg/kg reporting limit) to 265 mg/kg. In 2009, detections of HCB were
encompassed within the horizontal footprint of mercury. A comparison of HCB surficial
sediment concentrations in 2009 and 1991/1992/1994 is provided on Figure 16.
Only the 4,4'-isomers of DDT, DDE, and DDD (collectively, DDTr) were analyzed in
1991 as part of the Rl and in 2008. However, DDTR (both 4,4'- and 2,4' isomers of
DDT, DDE, and DDD) were analyzed in subsequent investigations in the 1990s and
2001, as well as 2009.
DDTR concentrations ranged from 0.06 mg/kg to 2.68 mg/kg in 2009 and DDTr ranged
from < 0.014 mg/kg to 0.739 mg/kg in 2009. DDTr concentrations decreased from north
to south for the Rl data. The higher concentrations of DDTr/DDTR were detected in the
southern portion of the Basin in 2009. Although the 2009 results show an approximate
order of magnitude decrease in DDTr concentrations from 1991, when concentrations
ranged from 0.272 mg/kg to 6.9 mg/kg; the sampling locations were different. A
comparison of DDTr/DDTR surficial sediment concentrations in 2009 and 1991/1992 is
provided on Figure 17.
Sediment Cores
Coarsely Sectioned Cores
Coarsely sectioned core samples were collected at 13 locations throughout the Basin in
2009, as shown on Figure 18. Analytical results for the coarsely sectioned sediment
cores are presented in Table 5.
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Relatively lower mercury concentrations were encountered near the sediment surface
interface (top of cores) at locations in the southern portion of the Basin (SDCR-1, -2),
central portion of the Basin (SDCR-4, -5), deeper portion of the Basin (SDCR-8), and
northern portion of the Basin (SDCR-10). Relatively higher mercury concentrations
appeared closer to the sediment surface in other locations in the southern portion of the
Basin (SDCR-3), the central portion of the Basin (SDCR-6, -7, -9), the northern portion
of the Basin (SDCR-11), and Round Pond (SDCR-12, -13). Vertical migration of
mercury within the sediment deposits was not evident in the data from the 2009
sediment for fine and coarse cores.
Groundwater seepage velocity and erosion/relocation during storm events may also
effect migration of mercury if the magnitude of the groundwater seepage velocity and
storm event is sufficient. Groundwater seepage will be evaluated during the remedial
design.
The mercury deposition pattern indicates that intervals where mercury concentrations
are greater than 0.2 mg/kg form a wedge that narrows as one moves north and east
from the former discharge ditch across the Basin.
Analytical results for HCB and DDTR for the coarsely sectioned cores are given in Table
5. These constituents were detected within the footprint of mercury.
Density, grain size, and percent solids of the coarsely sectioned sediment cores were
also analyzed; the analytical results are presented in Table 5. Density and percent
solids generally increased with depth at the sediment core locations. Grain size analysis
indicated that clay and silt-sized particles were predominant in the sediment cores
collected. These results were consistent with the lithological descriptions of the
sediment core logs. The bottom-most layers of each of the sediment cores showed the
presence of a dense layer of clay, indicating possible resistance in permeation to the
underlying sandy aquifer.
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Two sediment samples from SDCR-3 and SDCR-9 at the 0- to 1-foot sample interval
were also analyzed for mercury using the synthetic precipitation leaching procedure
(SPLP). The SPLP results were 0.03 milligram per liter (mg/L).
Finely Sectioned Cores
Finely sectioned core samples were collected at six locations throughout the Basin, as
shown on Figure 18. Samples were collected from 0 to 2, 2 to 4, 4 to 8, 8 to 12, and 12
to 18 inches. Samples were analyzed for mercury, methylmercury, percent moisture,
and TOC. These analytical results are presented in Table 6. A detailed description of
the fine core results are provided in the Rl report. Results were used as input to model
transport of mercury through cap material in the FS.
2.5.3.4 Wind-Driven Resuspension Study and Model
The Rl report modeled the potential for wind-driven resuspension of sediment using the
Bachmann-Hoyer-Canfield (BHC) model. The BHC model uses wind velocity and
effective fetch to calculate wave period and wave length to determine the water depth to
which various wind-speeds disturb the sediment bottom. The model used the maximum
fetch (i.e. maximum dimension across the Basin) to calculate wave period and length,
therefore maximizing wave height in the model. Wind speeds in the model were
obtained from measurements taken at the plant site from November 2007 to January
2009. The modeled results showed that wind-speeds of 10 mph or less occur 94% of
the time in the Basin, and these winds can result in sediment resuspension in water
depths of 3 ft or less. The primary uncertainty that was not evaluated regarding wind-
driven resuspension is the relative importance of the more frequent low wind-speed
events compared to the less frequent high wind speed events in the mobilization and
redistribution of bed sediments. While the EPA agrees that maintenance of higher water
levels may reduce the potential for sediment resuspension in the most contaminated
areas under low wind-speed events, there is concern that potential negative effects
associated with maintenance of higher water levels have not been evaluated. Potential
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negative effects include increased methylation, and increased bioaccumulation due to
increased water residence time within the Basin. Due to these concerns, Olin has
agreed that maintenance of higher water levels will not be a part of any permanent
remedy within the Olin Basin.
2.5.3.5 Surface Water
A summary of surface water analytical results for 2006, 2008, and 2009 is provided in
Table 7. The 2009 surface water sampling locations are shown in Figure 19.
Mercury concentrations in surface water in 2009 ranged from 0.00731 micrograms per
liter (|jg/L) to 0.155 |jg/L in unfiltered samples and from 0.00357 |jg/L to 0.0147 |jg/L in
filtered (0.45 |jm) samples. Average mercury concentrations per transect (in both filtered
and unfiltered surface water samples) decreased from north to south in the Basin and
were lowest in Round Pond; however, the ranges of concentrations overlapped.
Average mercury concentrations were lower at shallow sample locations (20 percent of
total water depth) than at deep sample locations (80 percent of total water depth).
Shallow unfiltered mercury concentrations averaged 0.0239 |jg/L, and shallow filtered
mercury concentrations averaged 0.00574 |jg/L. Deep unfiltered mercury concentrations
averaged 0.0706 |jg/L, and deep filtered mercury concentrations averaged 0.00988
mq/l.
Methylmercury concentrations in 2009 samples, ranged from 0.000613 |jg/L to 0.00171
|jg/L in unfiltered surface water samples and from 0.000413 |jg/L to 0.000649 |jg/L in
filtered surface water samples. Filtered methylmercury concentrations in shallow water
samples averaged 0.000452 |jg/L, and unfiltered methylmercury in shallow water
samples averaged 0.000831 |jg/L. Average filtered methylmercury in deep water
samples was 0.000508 |jg/L, and unfiltered average methylmercury was 0.000873 |jg/L.
Average methylmercury concentrations in filtered surface water samples decreased
from north to south in the Basin; however, the ranges of concentrations overlapped.
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Average methylmercury concentrations in the filtered and unfiltered surface water
samples increased from 2006 to 2008 and decreased from 2008 to 2009. The 2009
methylmercury average concentration was similar to that in 2006.
Results for mercury, methylmercury, HCB, DDT and metabolites, and other key water
quality parameters for surface water during 1991, 1992, 1994, 1995, and 2001 are
presented in Table 2.
2.5.3.6 Biota
Terrestrial Vegetation
The results for mercury, methylmercury, HCB, DDTR, and percent lipids in terrestrial
vegetation are summarized below. Vegetation sampled as part of this effort included
vines and leaves from shrubs near associated soil samples. Individual results are
provided in Table 8 and graphically depicted in Figure 20. Vegetation results for COCs
are reported as wet weight. Percent lipids in vegetation ranged from 0.13 to 0.4 percent.
Mercury was not detected in terrestrial vegetation samples above the RL of 0.017
mg/kg. Methylmercury was detected in the terrestrial vegetation samples at
concentrations ranging from 0.000643 JQ mg/kg (JQ indicates an estimated
concentration between the method detection limit [MDL] and the RL) to
0.0147 mg/kg. The average methylmercury tissue concentration was 0.00314 mg/kg.
Six of the 10 vegetation samples had methylmercury concentrations between the MDL
and the RL.
HCB was analyzed in five vegetation samples, but was only detected above the
reporting limit in one sample (FPVSS14) at 0.0048 J mg/kg. DDTR was analyzed in five
vegetation samples. The results for the six analyzed congeners were summed to obtain
the DDTR value. Zero was used in the summations for congeners that were not
detected at the associated RL for the sample. DDTR was detected above the RL
in one sample, FPVSS-1 (northeast of the Basin), at 0.0045 J mg/kg.
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Spiders and Insects
The results for mercury, HCB, DDTR, and percent lipids in spiders and insects are
summarized below.
Individual results are provided in Table 9. Spider and insect results for COCs are
reported as wet weight.
Mercury concentrations in spiders collected in the OU-2 floodplain in 2010 ranged from
0.13mg/kg to 0.17 mg/kg and were similar throughout the floodplain. HCB
concentrations in spiders ranged from 0.001 JQ mg/kg to 0.016 mg/kg. DDTR
concentrations in spiders ranged from 0.141 mg/kg to 0.335 mg/kg. The results for the
six analyzed congeners were summed to obtain the DDTR value. Zero was used in the
summations for congeners that were not detected at the associated RL for the sample.
This method was also used for flying and crawling insects. Summations of congeners
were also calculated using one-half of the RL for non-detected concentrations at the
EPA's request for evaluating uncertainty in non-detected concentrations. These
summations resulted in DDTR concentrations ranging from 0.14 JQ mg/kg to 0.33 JQ
mg/kg. Percent lipids in spiders ranged from 3.5 to 3.9 percent.
Mercury concentrations in flying insects ranged from 0.14 mg/kg to 0.71 mg/kg. HCB
concentrations in flying insects ranged from 0.002 JQ mg/kg to 0.039 mg/kg. DDTR in
flying insects (non-detect [ND] = 0) ranged from 0.038 J mg/kg to 0.659 J mg/kg. DDTR
in flying insects using one-half the RL for non-detects ranged from 0.05 JQ mg/kg to
0.66 J mg/kg. Percent lipids in flying insects ranged from 3.2 to 4.1 percent.
Mercury concentrations in crawling insects ranged from 0.008 JQ mg/kg to 0.37 mg/kg.
HCB concentrations in crawling insects ranged from 0.002 JQ mg/kg to 0.035 mg/kg.
DDTR in crawling insects (ND = 0) ranged from 0.004 JQ mg/kg to 0.352 mg/kg. DDTR
in crawling insects using one-half the RL for non-detects ranged from 0.015 JQ mg/kg to
0.35 J mg/kg. Percent lipids in crawling insects ranged from 2.8 to 4.4 percent.
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Fish
Fish tissue samples have been collected from the Basin since 1986, with the most
recent collection occurring in 2008. Fish species collected for tissue analysis from the
Basin include largemouth bass, channel catfish, bluegill, smallmouth buffalo, rock bass,
mosquitofish, brook silversides, and mullet.
These species are discussed in this section by trophic level. The fish tissue samples
have been analyzed historically for mercury, HCB, and DDTR. The movement of
mercury, HCB, and DDTR through the food web can be discussed, by examining the
fish tissue concentrations of mercury, HCB, and DDTR in fish species that are
representative of different trophic levels.
Trends in Fish Concentrations
Summaries of recent (2003 - 2010) and historical (1986 - 2001) fish tissue data are
presented in Tables 10 and 11, respectively. Trends in fish tissue concentrations over
time in the Basin are summarized as follows:
• Mercury concentrations in upper trophic level fish (largemouth bass) increased
from 2006 to 2008. This is likely due to drought conditions during this time period
that limited water exchange with the Tombigbee River. A decrease in mercury
concentrations in bass was noted in 2010, subsequent to the end of the drought
in 2009. However, concentrations of mercury in largemouth bass have not
decreased overtime compared to historical largemouth bass samples. Mercury
concentrations in lower trophic level fish have remained relatively constant from
1994-2010.
• HCB concentrations in the upper trophic level fish have decreased over time.
HCB concentrations in lower trophic level fish show a slight decreasing trend,
though concentrations increased in 2008 during the drought. The 2010 data
show that HCB concentrations in lower trophic level fish declined to historical
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pre-drought levels. No middle trophic level fish sampled from multiple years were
available for historical trend comparison.
• DDTR concentrations in the upper and lower trophic level fish have decreased
over time (1991 - 2010). No middle trophic level fish sampled from multiple years
were available for historical trend comparison
Other Biota
Benthic macroinvertebrate sampling was performed to characterize the infaunal
community at OU-2. The sampling was performed in three phases: during the RI/FS
investigation in 1991 and 1992 and during the additional ecological studies in 1994.
Table 12 provides a summary of the biota analytical results. The benthic community at
OU-2 was dominated by oligochaetes (segmented worms, especially of the families
Tubificidae and Naididae); larval dipteran insects (especially chironomids [midges] and
chaoborids [phantom midges]); and ostracods, as would be expected in a freshwater or
oligohaline environment such as OU-2.
2.5.4 Evaluation of Sedimentation Rate
Total suspended solids (TSS) data collected during 2008 and 2009 storm events were
used to estimate sediment load associated with representative storm events. The net
sedimentation rate (NSR) for the five year period from 2005 to 2009 was estimated
based on available Site-specific data. The predicted NSRs for 2005 to 2009 ranged
from 0 inch/year during the drought in 2007 to 0.3 inch/year in 2009. The average NSR
for this 5-year period was 0.2 inch/year.
The analysis was applied to the 49-year period of historic flow data collected at
Coffeeville Dam from 1961 through 2009 to represent a larger set of climatic conditions.
The annual NSR ranged from a minimum of 0.0 inch/year in 1963 to a maximum of 1.1
inch/year in 1983. Based on these results, the estimated annual average NSR in the
Basin was 0.3 inch/year for the 49-year period, with the 95 percent confidence interval
ranging from 0.2 to 0.4 inch/year.
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Most of the storm event data were collected during a low-flow period or drought
conditions in 2008 and were then applied to represent the quality of storm events from
1961 to 2009. As a result of data collection under drought conditions, annual NSR
estimates may be lower than the actual long-term average value.
2.5.5 Debris Evaluation
Sidescan sonar data collected during the bathymetric survey revealed that substantial
amounts of buried debris are present in the Basin. Buried debris is significantly larger
closer to the Basin edge, up to tens of meters long, several meters wide, and protruding
from tens of centimeters to up to a meter from the Basin bed.
This buried debris consists of larger logs and stumps. Approximately 50 percent of the
Basin edges are characterized by buried debris of this type. The shallower portion of the
Basin (less than approximately -8 meters water depth NAVD88) has numerous smaller
features, ranging from less than 1 meter to several meters long, and up to 1 meter or
more wide. The average length and/or width of these features is approximately 60
centimeters, with an average height above the sediment bed of less than 20
centimeters, and these features are interpreted to be tree branches and/or other forest
litter. This smaller buried debris is more prevalent in the southern portion of the Basin
(covering approximately 40 to 50 percent of the Basin bottom) than in the northern
portion (approximately 30 percent of the Basin bottom). The deeper portion of the Basin
in the northwestern quadrant is composed of significantly softer sediment, which
absorbs the seismic energy and results in fewer apparent features (approximately 15
percent of the Basin bottom). The features that are observed are approximately the
same size as the larger features of the shallower areas described above, likely tree
branches and/or other forest litter. Smaller features might be buried in the softer
sediments of the deeper Basin region, or might not reflect sufficient energy to be
detectable in the sidescan sonar record.
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2.6 CURRENT AND POTENTIAL FUTURE LAND AND RESOURCE USES
Residential land use within 3 miles of OU-2 includes approximately 94 households
(2000 U.S. Census). Commercial activity is generally related to basic domestic needs
and services along Highway 43. The two main industries within a 3-mile radius of OU-2
are the Olin and BASF (formerly Ciba-Geigy) facilities. A compressed air power plant
(Alabama Power) and a cement company are also within a 3-mile radius. Recreation
areas include the town park next to River Road, and a fishing camp at Mcintosh
Landing. Public use areas within a 3-mile radius include town government buildings,
public schools, a public library, churches, and cemeteries. The predominant land use
with a 3-mile radius is forest, followed by wetland areas.
USFWS classifies OU-2 as seasonally-flooded wetlands, and as such, not suitable for
human habitation. More than 95 percent of OU-2 is subject to flooding by the
Tombigbee River. Under ADEM's Water Quality Program, the water use classification
for the Tombigbee River in the vicinity of the Olin Basin is Fish and Wildlife. Table 13
provides an estimate of the vegetation/land cover types within OU-2.
The area surrounding OU-2 is comprised of a riverine ecoregion of large, sluggish rivers
and backwaters with ponds, swamps, and oxbow lakes. River swamp forests of bald
cypress and water tupelo and oak dominate bottomland hardwood forests and provide
important wildlife corridors and habitat.
Current and future offsite land use is expected to remain unchanged.
2.7 SUMMARY OF SITE RISKS
A Baseline Risk Assessment (BRA) was performed to estimate the probability and
magnitude of potential adverse human health and environmental effects from exposure
to contaminants associated with the Site assuming no remedial action was taken. It
provides the basis for taking action and identifies the contaminants and exposure
pathways that need to be addressed by the remedial action. The public health risk
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assessment followed a four step process: 1) hazard identification, which identified those
hazardous substances which, given the specifics of the site were of significant concern;
2) exposure assessment, which identified actual or potential exposure pathways,
characterized the potentially exposed populations, and determined the extent of
possible exposure; 3) toxicity assessment, which considered the types and magnitude
of adverse health effects associated with exposure to hazardous substances, and 4)
risk characterization and uncertainty analysis, which integrated the three earlier steps to
summarize the potential and actual risks posed by hazardous substances at the site,
including carcinogenic and noncarcinogenic risks and a discussion of the uncertainty in
the risk estimates. A summary of those aspects of the human health risk assessment
which support the need for remedial action is discussed below followed by a summary
of the environmental risk assessment.
The response action selected in this Record of Decision is necessary to protect the
public health or welfare or the environment from actual or threatened releases of
hazardous substances into the environment.
2.7.1 Human Health Risk Assessment
2.7.1.1 Chemicals of Concern
The Chemicals of Potential Concern (COPCs) were selected to represent potential site
related hazards based on toxicity, concentration, frequency of detection, and mobility
and persistence in the environment.
COPCs are defined as those chemicals that exceeded screening criteria and required
quantification in the Baseline Risk Assessment. COPCs were developed separately for
human health and ecological risk assessment. The following table provides a list of
COPCs that were evaluated in the human health risk assessment (HHRA).
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COPCs
Sediment
Mercury
Methylmercury
HCB
DDTR
Surface Water
Mercury
Methylmercury
HCB
DDTR
Surface Soil
Mercury
HCB
DDTR
The HHRA identified a subset of the COPCs as presenting a significant current or future
risk and are referred to as the Chemicals of Concern (COCs) in this ROD.
Methylmercury in fish tissue is identified as the primary COC for human health at OU-2.
Although mercury in fish tissue was measured as total mercury, it is presumed to be
primarily in the form of methylmercury, as other studies have shown that greater than
90% of mercury in fish tissue exists as methylmercury. Clean-up goals for sediment and
fish tissue for protection of human health are expressed in terms of total mercury
(methylmercury + inorganic mercury). The following sections summarize the process
used to identify the COC.
Exposure pathways considered included incidental ingestion of soil, dermal contact with
soil, and inhalation of particulates while trespassing at OU-2. Additional exposure
pathways included incidental ingestion of surface water during swimming, dermal
contact with surface water during swimming, and ingestion of largemouth bass fillets.
The recreational fishing scenario assumes that ingestion offish is limited to skinless
fillets, and that ingestion of whole fish is not occurring amongst the general population
or subgroups of the population. The exposure pathways are shown in Table 14.
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Exposure media evaluated in the human health risk assessment included floodplain soil,
surface water, and ingested fish fillets. COPCs in surface water include mercury, HCB
and DDTR. The COPCs in floodplain soil include mercury and DDTR. COPCs in fish
tissue included mercury (assumed to be methylmercury), HCB, and DDTR.
In the HHRA, the EPA uses a concentration for each COPC to calculate the risk. This
concentration, called the exposure point concentration, is a statistically-derived number
based on the sampling data for the Site. Generally, the 95 percent upper confidence
limit (UCL) on the arithmetic mean concentration for a chemical is used as the exposure
point concentration. The 95 percent UCL on the arithmetic mean is defined as a value
that, when calculated repeatedly for randomly drawn subsets of the Site data, equals or
exceeds the true mean 95 percent of the time. Exposure point concentrations for each
exposure medium are shown in Table 15.
2.7.1.3 Exposure Assessment
An exposure assessment was conducted as part of the HHRA. The exposure
assessment consists of characterizing the potentially exposed receptors, identifying
exposure pathways, and quantifying exposure. Exposure scenarios and pathways were
identified based on the conceptual Site model (Figure 8). An exposure pathway usually
includes the following: (1) a source and means of contaminant release; (2) a transport
medium (e.g., air, ground water, etc.); (3) a point of contact with the medium (i.e.,
receptor); and (4) an intake route (e.g., inhalation, ingestion, etc.).
The source and primary release for the constituents detected were through transport to
surface water. Transport to floodplain soils and bioaccumulation of constituents from
surface water and sediment to fish residing in the Basin are also relevant transport
pathways at OU-2. As shown in Table 14, direct contact with floodplain soils and
surface water, incidental ingestion of floodplain soils and surface water, inhalation of
floodplain soil particulate emissions, and ingestion offish fillets were considered as
potential exposure media and pathways of concern. Sediment is submerged and direct
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exposure to sediment is not a significant exposure pathway to humans at the Site.
The complete exposure pathways identified for this Site were carried through the human
health risk assessment. Current and future offsite land use is expected to remain
unchanged. Residential and industrial scenarios were not evaluated for potential future
use scenarios because the area consists of floodplains that flood annually, precluding
the construction of structures on the Site. The most likely receptors include offsite
resident trespassers (adults and adolescents aged 7 to 16 years) that may have
infrequent access to OU-2. Exposure pathways addressed in the human health risk
assessment are summarized below:
Current and Potential Future Offsite Adult and Adolescent Trespassers
• Incidental ingestion of surface water during swimming or fishing
• Dermal contact with surface water during swimming or fishing
• Ingestion of largemouth bass fish fillets
• Incidental ingestion, dermal contact, and inhalation of particulates from floodplain
soils during trespassing
Exposure Assumptions
For resident trespasser exposures, the reasonable maximum exposure (RME) duration
for an adolescent was assumed to be 10 years (Site-specific assumption) with 30 years
assumed for adults. For trespassing and swimming exposures, a Site-specific current
exposure frequency of 12 days/year was assumed (i.e., one day per month), and is
based on a 1993 fishing survey. Information regarding fishing activity behavior was
obtained from a subpopulation that claimed to have actually fished in the Basin. The
most conservative response was once per month. This frequency is likely an
overestimation because construction in 2007 and continued operation of the berm and
gate system further limits access since the survey was conducted in 1993. Therefore, it
is likely that an exposure frequency of 12 days per year overestimates current
exposures. Per the EPA requirement, trespassers were assumed to have increased
exposure in the future scenario. For trespassing and swimming exposures, a potential
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future exposure frequency of 45 days/year is assumed.
A body weight of 70 kg is assumed for adult resident trespassers and a body weight of
48 kg is assumed for adolescent resident trespassers (7 to 16 years of age). The
averaging time for noncarcinogenic exposures is equal to the exposure duration times
of 365 days. The averaging time for carcinogenic exposures is assumed to occur over a
70-year lifetime (25,550 days).
Incidental Ingestion of Surface Water
It is assumed that adult and adolescent trespassers ingest 0.02 liter per hour (L/hr) and
0.05 L/hr, respectively for two hours per event (professional judgment).
Dermal Contact with Surface Water
A total body surface area of 18,000 cm2 and 14,110 cm2 was assumed for resident
trespasser adults and adolescents, respectively.
Ingestion of Fish Fillets
The daily intake offish is based on the 95th percentile intake for uncooked fish weight in
grams per day (g/day) from a freshwater and estuarine source. Adult trespassers are
assumed to eat 31.9 g/day. Adolescents are assumed to ingest 17 g/day. The
adolescent rate is an age-adjusted rate. The fraction offish ingested from the Site was
based on the non-flood season for OU-2 and the results of the 1993 fishing survey. The
fishermen responded that they did not fish during the flood season, which is the only
time boat access is available. In the 1993 human health risk assessment, a fraction
ingested from the Basin of 0.125 was calculated (or 1/8 of total fish ingested per year).
This value was retained for the current exposure fraction ingested in the updated human
health risk assessment. However, based on construction in 2007 and continued
operation of the berm and gate system that serve to limit Site access, the assumptions
based on the 1993 survey potentially overestimate current exposures to OU-2 media.
Per the assumption that access restrictions could be reduced in the future, a higher
fraction ingested from the Site was assumed (0.5) for the future scenario. The 1993
human health risk assessment included the ingestion of catfish and bass, but the
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current human health risk assessment assumes only ingestion of bass. Using
concentrations for just largemouth bass is a conservative approach to the estimation of
exposures for trespassing fishermen because bass have a long lifespan and tend to
bioaccumulate more COPCs than other species. Fillet data collected in the Basin in
1991 and 2003 show that bass fillets contain higher concentrations of mercury than
catfish fillets, while concentrations of DDTR in the two species were similar.
Ingestion of Soil
The daily intake of soil for adults and adolescents is assumed to be 100 mg/day. Fifty
percent of the daily soil intake is assumed to be from the Site.
Dermal Contact with Soil
The exposed surface area is assumed to be hands, forearms, feet, and lower legs with
the adult and adolescent surface areas calculated as 5,700 cm2/event and 4,050
cm2/event, respectively.
Inhalation of Particulates Emitted from Floodplain Surface Soils
Trespassers are assumed to have 50 percent of their daily dose from the Site. A default
particulate emission factor from the EPA guidance (USEPA, 2002b), 1.36 x 109 m3/kg, is
used to estimate particulate emissions at the Site. Because of the wet nature of some of
the soil and the presence of vegetation, inhalation of particulate emissions at the Site is
expected to be a minor pathway of exposure.
Sediment Dermal Contact and Incidental Ingestion
Direct contact with submerged sediment and incidental ingestion of submerged
sediment are considered incomplete exposure pathways for the exposure scenarios at
OU-2. Though dermal contact with submerged sediments may occur to people wading
in the Basin, dermal absorption is considered negligible because sediments are
continually being washed from the skin by the surface water.
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2.7.1.4 Toxicity Assessment
The toxicity assessment is an integral part of the risk evaluation process. Toxicity
values, such as reference doses and carcinogenic slope factors, are based primarily on
human and animal studies with supportive evidence from pharmacokinetics,
mutagenicity, and chemical structure studies. The EPA has developed toxicity values
that reflect the magnitude of adverse non-carcinogenic and carcinogenic effects from
exposure to specific chemicals. The hierarchy of sources for toxicity values used in the
human health risk assessment is 1) the EPA's Integrated Risk Information System
(IRIS) database, 2) the National Center for Environmental Assessment Provisional Peer
Reviewed Toxicity Values, and 3) other reviewed toxicity values as published in the
EPA RSL table (USEPA, 2010). Values for this HHRA were available in
IRIS. A summary of the toxicity assessment is provided in Tables 16-17.
Toxicity Values for Non-carcinogenic Effects
Chemicals that give rise to toxic endpoints other than cancer and gene mutations are
often referred to as "systemic toxicants" because of their effects on the function of
various organ systems. Chemicals considered carcinogenic can also exhibit systemic
toxicity effects. For many non-carcinogenic effects, protective mechanisms (i.e.,
exposure or dose threshold) are believed to exist that must be overcome
before an adverse effect is manifested. This characteristic distinguishes systemic
toxicants from carcinogens and mutagens, which are often treated as acting without a
distinct effects threshold. As a result, a range of exposure exists from zero to some
finite value that can be tolerated with essentially no risk of the organism expressing
adverse effects. The standard approach for developing toxicity values to evaluate non-
carcinogenic effects is to identify the upper bound of this tolerance range or threshold
and to establish the toxicity values based on this threshold.
The toxicity values most often used in evaluating non-carcinogenic effects are a
reference concentration (RfC) or reference dose (RfD) for inhalation and oral
exposures, respectively. Various types of non-carcinogenic toxicity values are available
depending on the exposure route of concern (e.g., oral or inhalation), the critical effect
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of the chemical (e.g., developmental or other), and the length of exposure being
evaluated (e.g., chronic or subchronic).
The RfC and RfD are defined as provisional estimated daily exposure levels for the
human population, including sensitive subpopulations that are likely to be without
appreciable risk of deleterious effects during a portion of a lifetime or a lifetime
(chronic). Chronic RfCs/RfDs are specifically developed to be protective for long-term
exposures, (i.e., 7 years to a lifetime of 70 years) and subchronic exposures are
developed to be protective for short-term exposures. Chronic RfCs/RfDs were used in
the human health risk assessment.
Toxicity Values for Carcinogenic Effects
Carcinogenesis, unlike many noncarcinogenic health effects, is generally thought to be
a non-threshold effect. Accordingly, the EPA guidance for risk assessments assumes
that a small number of molecular events can cause changes in a single cell that can
lead to uncontrolled cellular growth. This hypothesized mechanism for carcinogenesis is
referred to as "non-threshold" because any level of exposure to such a chemical is
considered as posing a finite probability of generating a carcinogenic response.
To evaluate carcinogenic effects, the EPA uses a two-part evaluation in which the
chemical is first assigned a weight-of-evidence classification, and then either an
inhalation unit risk (IUR) or oral carcinogenic slope factor (CSF) is calculated. The
weight-of-evidence classification is based on an evaluation of available data to
determine the likelihood that the chemical is a human carcinogen.
Chemicals with the strongest evidence of human carcinogenicity are denoted with Class
A, B1, or B2, while chemicals with less supporting evidence are classified as C or D.
The slope factor quantitatively defines the relationship between the dose and the
response. The slope factor is generally expressed as a plausible upper-bound estimate
of the probability of response occurring per unit of chemical.
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Toxicity Assessment of Dermal Exposures
RfDs or CSFs have not been derived specifically for dermal absorption. The
administered oral RfDs and CSFs may be adjusted by chemical-specific gastrointestinal
(Gl) absorption rates, resulting in an absorbed dose RfD or CSF, as described in the
EPA's risk assessment guidance (USEPA, 1989). The Gl absorption rates are obtained
from RAGS Part E (USEPA, 2004; 2010b). To evaluate potential risks from
dermal exposures, the dermal intakes are compared to the adjusted (i.e., absorbed
dose) toxicity values (USEPA, 1989). In accordance with RAGS Part E, when values for
oral absorption efficiency are greater than 50 percent, the oral RfD and oral CSF are not
adjusted for Gl absorption.
2.7.1.5 Risk Characterization
The final step of the risk assessment process is called risk characterization. Risk
characterization combines the exposure assessment with the toxicity assessment. The
toxicity assessment evaluates the relationship between a dose of a chemical and the
predicted occurrence of an adverse health effect. In the risk assessment, toxic effects
are separated into two categories: cancer (carcinogenic) effects and non-cancer (non-
carcinogenic) effects.
Non-carcinogenic Effects Characterization
The potential for non-carcinogenic effects is evaluated by comparing an exposure level
over a specified time period (e.g., life-time) with a reference dose (RfD) derived for a
similar exposure period. An RfD represents a level that an individual may be exposed to
that is not expected to cause any deleterious effect. The ratio of the daily intake to the
RfC/RfD is referred to as the "hazard quotient: or HQ. The sum of the hazard quotients
for each chemical in a specific pathway is termed the "hazard index" or HI. The HI is
generated by adding the HQs for all chemical(s) of concern that effect the same target
organ (e.g., liver) or that act through the same mechanism of action within a medium or
across all media to which a given individual may reasonably be exposed. An HI < 1
indicates that, based on the sum of all HQ's from different contaminants and exposure
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routes, toxic non-carcinogenic effects from all contaminants are unlikely. An HI > 1
indicates that site-related exposures may present a risk to human health.
The HQ is calculated as follows:
Non-cancer HQ = CDI/RfD
where:
CDI = Chronic Daily Intake
RfD = Reference Dose
CDI and RfD are expressed in the same units and represent the same exposure period
(i.e., chronic, subchronic, or short-term). SF = slope factor, expressed as (mg/kg-day)"1.
The EPA's generally acceptable risk range contaminant is less than the RfD, and toxic
non-carcinogenic effects from that chemical are unlikely. Non-carcinogenic effects are
characterized by comparing the estimated chemical intakes to the appropriate RfC or
RfD values. The RfC/RfD value is, by definition, an estimate of a daily exposure level for
the human population, including sensitive subpopulations, that is likely to be without
appreciable hazard of deleterious effects during a lifetime. Therefore, when the
estimated chronic daily intake of a chemical exceeds the appropriate RfC or RfD, there
may be a concern for potential noncancer effects from exposure to that chemical. The
ratio of the daily intake to the RfC/RfD is referred to as the "hazard quotient" or HQ. The
sum of the hazard quotients for each chemical in a specific pathway is termed the
"hazard index" or HI. It is important to note that the hazard quotient does not represent a
statistical probability; thus, a ratio of 0.01 does not mean that there is a 1 in 100 chance
of the effect occurring. Rather, HQ greater than 1 indicates that the "threshold" for that
constituent has been exceeded.
The EPA assumes additive effects in evaluating non-carcinogenic effects from a mixture
of chemicals. Strictly, additivity should only be assumed for chemicals that induce the
same effect by the same mechanism of action. Practically, this consideration is often
addressed by adding His for chemicals that critically affect the same target organ
system, and additivity across chemicals affecting the same target organ has been
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addressed in this assessment. The constituent-specific hazard quotients are summed to
yield an overall pathway HI; pathway His are then summed to yield a total HI for each
relevant population. The current and potential future risk characterization tables (non-
carcinogens) for adult and pre-adolescent/adolescent resident trespasser exposures to
surface water, floodplain surface soil, and fish tissue are presented in Tables 18 through
21. The constituent-specific HQs are grouped and summed by target organ.
Carcinogenic Risk Characterization
For carcinogens, risks are generally expressed as the incremental probability of an
individual developing cancer over a lifetime as a result of exposure to the carcinogen.
Excess lifetime cancer risk is calculated from the following equation:
Risk = CDI x SF
where:
Risk = a unitless probability (e.g., 2 x 10~5) of an individual's
developing cancer
CDI = chronic daily intake averaged over 70 years (mg/kg-day).
SF = slope factor, expressed as (mg/kg-day)"1
These risks are probabilities that usually are expressed in scientific notation (e.g., 1x10"
6). An excess lifetime cancer risk of 1x10"6 indicates that an individual experiencing the
reasonable maximum exposure estimate has a 1 in 1,000,000 chance of developing
cancer as a result of site-related exposure. This is referred to as an "excess lifetime
cancer risk" because it would be in addition to the risks of cancer individuals face from
other causes such as smoking or exposure to too much sun. The chance of an
individual's developing cancer from all other causes has been estimated to be as high
as one in three.
Risks from potential carcinogens are estimated as probabilities of excess cancers as a
result of exposure to chemicals. The carcinogenic slope factor correlates estimated total
lifetime daily intake directly to incremental cancer risk. The results of the risk
characterization are expressed as upper bound estimates of the potential carcinogenic
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risk for each exposure point. Constituent-specific cancer risks are estimated by
multiplying the slope factor by the lifetime daily intake estimates.
To be protective of human health, cumulative risk for carcinogenic compounds should
be calculated so that the result does not exceed the acceptable risk range of 10~4 to 10"
6, with a cumulative upper bound excess lifetime cancer risk of one in 10,000 (1 * 10"4).
The current and potential future risk (carcinogens) characterization tables for adult and
pre-adolescent/adolescent resident trespasser exposures to surface water, floodplain
surface soil, and fish tissue are presented in Tables 22 through 25. For each receptor,
the exposure medium is calculated into an individual cancer risk and summarized into a
cumulative carcinogenic risk.
Summary of Risk Characterization
The COPCs were selected to represent potential Site related hazards based on toxicity,
concentration, frequency of detection, and mobility and persistence in the environment.
From this, a subset of the chemicals was identified as presenting a significant current or
future risk and the subset is referred to as the COCs in this ROD.
Exposures to floodplain soils were not associated with unacceptable risks or hazards
and were not carried through to the summary tables.
Carcinogenic risk for all scenarios (current and future) fell within the acceptable risk
range for all COPCs (maximum carcinogenic risk of 2.3 x 10"5 was to adult fisherman
under the future use scenario).
The noncarcinogenic risk HI values exceed 1 for adult and adolescent receptors for the
future use scenarios (HI = 4.0 to 6; Tables 18-21). The HI calculations show that the
risk is primarily due to ingestion of methylmercury in fish tissue. The ingestion pathway
accounted for 99.9% of the HI values, while dermal contact with soil and surface water,
and ingestion of soil and surface water accounted for less than 0.1% of the total HI
values for adult and adolescent receptors. Within the ingestion pathway, methylmercury
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in fish tissue accounted for 93 - 97% of the total HI, with ingestion of HCB and DDTR
accounting for 3 - 7% of the ingestion HI. Thus, methylmercury in fish tissue is identified
as the primary COC for human health at OU-2. Although mercury in fish tissue was
measured as total mercury, it is presumed to be primarily in the form of methylmercury,
as other studies have shown that greater than 90% of mercury in fish tissue exists as
methylmercury. Clean-up goals for sediment and fish tissue for protection of human
health are expressed in terms of total mercury (methylmercury + inorganic mercury).
Uncertainty Analysis
Uncertainty is inherent in the risk assessment process. Exposure is hypothetical, and
the risk assessment calculations are based in large part on assumed conditions. An
important part of the risk assessment process is characterizing the main underlying
uncertainties. Understanding the uncertainties is important for the interpretation and
ultimate use of the risk assessment results because actual risk may be underestimated
or overestimated.
Uncertainties and Assumptions Associated With Data Collection and Data Evaluation
The goal of the sampling at Olin OU-2 is to define nature and extent of contamination
and determine the EPCs for exposure media. The data for HCB and DDTR for surface
water are from historical sampling events and may not represent current conditions in
the Basin and Round Pond.
Uncertainties and Assumptions Associated with the Exposure Assessment
The use of UCLs of the arithmetic mean as a basis for estimating a reasonable
maximum exposure (RME) is a conservative approach designed to assure that the
mean is not underestimated. Actual EPCs may also vary with space and time.
Floodplain surface soil data were collected in 2010 and some of the data points were
submerged. However, all the data points were used as dry soil for purposes of the
human health risk assessment. Thus, inclusion of these wet soils may under or
overestimate soil exposures. However, inclusion of all sampling points is a conservative
measure that models exposure to a mixture of soil and sediment. This is appropriate
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because flood plain soils become submerged sediment during the frequent flooding
events that occur on the Tombigbee River.
Fish fillet tissues were analyzed for total mercury. An assumption was made that all
detected mercury in fish was methylmercury, because 90% (and greater) of mercury in
fish tissue generally exists as methylmercury.
The fish ingestion intakes assumed the ingestion of only one species offish.
Largemouth bass are upper trophic level fish with a long life span. They tend to
bioaccumulate higher concentrations of mercury than other species such as sunfish or
catfish. However, local fishermen reportedly eat a variety offish from the surrounding
area. Assuming ingestion of largemouth bass only may overestimate risks and hazards
associated with mercury, HCB, and DDTR, as historical data showed that largemouth
bass contained higher concentrations of mercury than other species that may be
consumed by humans, such as channel catfish. However, the assumption that only
skinless fillets are consumed may underestimate risk to anyone who consumes the
whole fish, as concentrations of DDT and HCB in whole fish are greater than
concentrations in skinless fillets. Assuming the local fishermen will obtain 50 percent of
the fish ingested from OU-2 in the future also may overestimate exposures to mercury,
HCB, and DDTR.
The receptor group of interest in human health is off Site resident trespasser adults and
adolescents. The Basin and Round Pond areas are not readily accessible from the river
because of the berm located on three sides of OU-2. Olin restricts access to this area.
The water level would have to be several feet above the berm elevation of 12 feet
NAVD88 to get a boat into OU-2 from the river. Fishermen reported that they do not fish
during the flood season when boat access is available. Olin is committed to maintaining
restricted access to OU-2 currently and in the future based on its current economic
investment at the manufacturing facility. Future exposures for OU-2, where Olin
maintains access restrictions, are expected to be very similar to current exposures in
regards to exposure frequency. Thus, assumptions developed in 1993 may
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overestimate current exposures because institutional controls cannot be assumed in the
risk analysis. Future exposure assumptions required by the EPA assume unrestricted
Site access. Based on Olin's long term commitment to the facility and to maintenance of
Site security at OU-2, the potential future scenario may overestimate hazards and risks
associated with fish ingestion. The current and future assumption that off Site residents
trespass, regularly swim, or fish tends to overestimate risks and hazards for OU-2.
Uncertainties and Assumptions Associated With the Toxicity Assessment
Substantial uncertainties are associated with use of toxicity data extrapolated from rats
and mice to humans. In some instances, biological pathways and mechanisms of
metabolism differ significantly between mammalian species. As a result of these
differences, humans may be either more or less sensitive than the surrogate laboratory
species. The application of uncertainty factors in the EPA's RfC/RfD assumes that
humans may be more sensitive, although this is not always the case. This
extrapolation will likely overestimate risk to some extent. Incorporation of variability in
response among individuals in the population is entirely appropriate to ensure that all
members of the exposed population are protected. The portion of the uncertainty factor
that represents true uncertainty, however, may result in overestimation of risk, even to
individuals predisposed to an adverse response.
Uncertainties and Assumptions Associated With the Risk Characterization
The use of conservative assumptions throughout the risk assessment tends to
overestimate potential risks and hazards. By examination of uncertainties associated
with the exposure assessment and the toxicity assessment, which are combined by
multiplication in the risk characterization, it is likely that the RME hazards and risks
reported are overestimated. The EPA intends for this approach to help ensure that
risks are not underestimated.
The EPA requires a potential future scenario that assumes unrestricted access to OU-2
or unlimited recreational exposures to surface soil, surface water, or fish from the Basin.
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This unrestricted potential future scenario has been incorporated into the HHRA.
However, these potential future increased exposures are unlikely to occur due to the
following current facts:
• Olin plans to continue to operate the facility and maintain Site security, which
limits access to the Basin and Round Pond; therefore, exposures to floodplain
soil, surface water, and fish tissues will also remain of low frequency; and
• Estimated carcinogenic risks and hazards under the current use scenario are
within acceptable limits (Risk Range = 3.2 x 10~5 to 2.0 x 10~6). Assuming the
plant continues operations, future potential exposures will likely remain similar to
those predicted in the current scenario. Non-carcinogenic risk shows HI values
greater than one for the future use scenarios (HI range = 4 to 6), with ingestion of
fish tissue driving the risk. The maximum HI of 6 is associated with future
exposure without access restrictions for adults fishing in the Basin.
2.7.2 Ecological Risk Assessment
2.7.2.1 Chemicals of Potential Concern (COPCs)
COPCs are defined as those chemicals that exceeded screening criteria identified in the
Screening Level Ecological Risk Assessment (SLERA) and required quantification in the
Ecological Risk Assessment (ERA). COPCs were developed separately for human
health and ecological risk assessment. Ecological COPCs were developed in the
Ecological Risk Assessment Report (WCC, 1995) using data collected for the OU-2
Remedial Investigation in 1991 and 1992. The data used to characterize the Site for the
screening-level ecological risk assessment are summarized in their entirely in the Rl
report (WWC, 1993). COPCs were refined based on frequency of detection and
magnitude of exceedance. The COPCs retained for the ERA are summarized below:
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This unrestricted potential future scenario has been incorporated into the HHRA.
However, these potential future increased exposures are unlikely to occur due to the
following current facts:
• Olin plans to continue to operate the facility and maintain Site security, which
limits access to the Basin and Round Pond; therefore, exposures to floodplain
soil, surface water, and fish tissues will also remain of low frequency; and
• Estimated carcinogenic risks and hazards under the current use scenario are
within acceptable limits (Risk Range = 3.2 x 10~5 to 2.0 x 10~6). Assuming the
plant continues operations, future potential exposures will likely remain similar to
those predicted in the current scenario. Non-carcinogenic risk shows HI values
greater than one for the future use scenarios (HI range = 4 to 6), with ingestion of
fish tissue driving the risk. The maximum HI of 6 is associated with future
exposure without access restrictions for adults fishing in the Basin.
2.7.2 Ecological Risk Assessment
2.7.2.1 Chemicals of Potential Concern (COPCs)
COPCs are defined as those chemicals that exceeded screening criteria identified in the
Screening Level Ecological Risk Assessment (SLERA) and required quantification in the
Ecological Risk Assessment (ERA). COPCs were developed separately for human
health and ecological risk assessment. Ecological COPCs were developed in the
Ecological Risk Assessment Report (WCC, 1995) using data collected for the OU-2
Remedial Investigation in 1991 and 1992. The data used to characterize the Site for the
screening-level ecological risk assessment are summarized in their entirely in the Rl
report (WWC, 1993). COPCs were refined based on frequency of detection and
magnitude of exceedance. The COPCs retained for the ERA are summarized below:
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COPCs
Sediment
Mercury
Methylmercury
HCB
DDTR
Surface Water
Mercury
Methylmercury
HCB
DDTR
Surface Soil
Mercury
HCB
DDTR
Based on the sediment, surface water, and surface soil screening results, the COPCs
that were carried forward in the 2011 ERA process for OU-2 include mercury,
methylmercury, HCB, and DDTR. The historical and current analytical results for these
COPCs were used to estimate EPCs.
The COPCs were selected to represent potential Site related hazards based on toxicity,
concentration, frequency of detection, and mobility and persistence in the environment.
The baseline risk assessment evaluated the COPCs, and based on the results of the
baseline risk assessment a subset of the chemicals were identified as presenting a
significant current or future risk and are referred to as the COCs in this ROD. The
ecological COCCs are DDTR, HCB and mercury (inorganic and methylmercury) (Table
26). The "Background" concentrations in Table 26 are based on concentrations
measured at the selected reference area for the OU-2 investigation. The Fred T.
Stimpson Wildlife Sanctuary near Jackson, Alabama was selected as the reference
area for COPC sampling. The reference area is located on the east side of the
Tombigbee River at river mile (RM) 78, about 10 straight-line miles from OU-2 (Figure
1-2 of WWC 1994). The sanctuary comprises 3,800 acres; the studies were performed
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in the vicinity of two water bodies, the Middle Cutoff lake (ca. 21 acres) and Lower
Cutoff lake (ca. 36 acres).
Exposure Point Concentrations
EPCs were based on concentrations to which receptor populations were expected to be
exposed. Ecological risk guidance states that the 95 percent upper confidence limit
(UCL) of the arithmetic mean should be used to develop EPCs. For instances where
samples are insufficient to calculate a UCL or the UCL exceeds the maximum
concentration, the maximum detected concentration can be used as a default
EPC. The UCLs were developed from multiple samples collected from numerous
locations over several years in most cases and used as EPCs where appropriate.
Insects (including crawling insects, spiders, and flying insects), terrestrial vegetation,
and floodplain soil EPCs were based on the 2010 sample collection (Figures 20 and
21). Sediment EPC calculations included the Basin and Round Pond sampling
locations. Separate Round Pond EPCs were also developed. EPCs were also
developed for two water level scenarios. EPCs were calculated for water levels at 3-feet
NAVD88 and at 6-feet NAVD88. The minimum water level currently held at OU-2 is 6-
feet NAVD88; a minimum water level was maintained starting in February 2009 to the
present. EPCs for a 3-foot water level were also provided to represent historical
baseline water levels and future water levels expected when operation of the gate and
berm system ceases. EPCs at both water level scenarios were developed to allow a
comparison of the EPCs for the differing water levels. Ecological EPCs for surface
water, sediment, and floodplain soil samples are shown in Table 26 as the 95% UCL of
the mean concentration. Constituents for which EPCs were developed included
mercury, methylmercury, HCB, and DDTR.
Sampling data used in these EPC calculations were selected to provide representation
across each medium and account for the actual likelihood of exposure for organisms to
media.
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2.7.2.2 Exposure Assessment
Environmental Setting
Considering the topography, hydrography, and associated biota (e.g., vegetative cover
types) OU-2 is composed of three major habitat types - permanent water bodies with
deepwater habitats, riparian wetlands, and uplands. Nearly 60 percent of the OU-2 is
wetland. A formal jurisdictional determination ("delineation") was not performed as part
of the Rl, but it is clear from the descriptions of the hydrology and the vegetation that
most of the OU-2 is riparian wetland. Soils east of the line tracing the edge of the bluff
are of the Urbo and Una Series, which are recognized by the U.S. Department of
Agriculture, Soil Conservation Service, as hydric. Therefore, all three criteria for formal
wetland status are met in the portions of OU-2 between the margins of the permanent
water bodies and the base of the bluff or the edge of the Tombigbee River.
Wetlands serve as habitat for a great diversity of organisms.
Vegetation
Six basic vascular plant communities, or vegetative cover types, were identified within
OU-2 as presented in Table 13. The cover types include ponds and streams (permanent
water bodies), semi-permanently/permanently flooded bottomland forest, temporarily
flooded bottomland forest, successional shrub-dominated bottomland areas,
herbaceous-dominated bottomland areas, and mixed hardwood/pine upland forest. The
vascular flora identified during the 1994 survey were consistent with the current
vegetative communities present on Site.
Details of vegetative community structure in these various habitat types (by stratum) are
available in earlier reports. There was some evidence of logging, apparently long before
the Olin Mcintosh Plant was developed. Disturbance also occurred to northern and
eastern portions of OU-2, which appeared to be related largely to construction of the
BASF (formerly Ciba-Giegy) effluent pipeline in the late 1980s. An approximately 6.4-
acre borrow area adjacent to OU-2 was cleared for the construction of the berm in
2006. The berm and gate system was constructed along the northern, eastern, and
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southern portions of OU-2 in 2006-2007. The detailed vegetative stress survey
conducted in the early 1990s and additional observations during recent field activities
revealed no indication of adverse effects of Site-related COPCs on individual plants,
populations, or communities in OU-2.
The temporarily flooded bottomland forest, semipermanently flooded bottomland forest,
and mixed upland forest all appeared to be typical of these types within the Southern
Pine Hills District of the Eastern Gulf Coastal Plain in terms of species composition and
structural characteristics. The limited signs of stress and disturbance in these wooded
areas included;
• Evidence of logging (apparently many decades ago)
• At least one (perhaps more) localized fire
• Localized physical disruption of the soil and/or hydrology (e.g., along where
BASF's discharge line was laid adjacent to the eastern property boundary of the
Site, where the berm was constructed around the Basin and Round Pond, and in
the borrow area on the top of the western bluff area)
Insect and disease damage, including webworms, chewing insects, and rusts, were
noted in scattered locations, but were not indicative of a pattern that could be
associated with any other stress(es), such as the presence of COPCs, fire, or
hydrologic factors. Other than the effects mentioned above, vegetative conditions
throughout OU-2 appear to be good, with normal vigor and color. Significant deformities
or other indications of altered plant growth were not found.
Benthic and Other Aquatic Invertebrates
Benthic macroinvertebrate sampling to characterize the infaunal community was
conducted in three phases at OU-2 during the RI/FS investigation in 1991 and 1992 and
during the additional ecological studies in 1994. The benthic community at OU-2 was
dominated by oligochaetes (segmented worms, especially of the families Tubificidae
and Naididae); larval dipteran insects (especially chironomids [midges] and chaoborids
[phantom midges]); and ostracods, as would be expected in a freshwater or oligohaline
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environment such as OU-2. There was a strong inverse correlation between taxonomic
richness and invertebrate densities versus depth, likely due to hypoxic conditions at
depth. Multivariate statistical analyses (clustering procedures) indicated no significant
relationships between benthic invertebrate diversities and densities and COPC
concentrations in the sediments. No clear patterns were evident in a qualitative
assessment of the distribution of pollutant tolerant or pollutant-sensitive taxa relative to
COPCs. Relatively high incidences of oligochaete worms with aberrant chetae were
noted in some locations, although these had no definite relationship to location specific
COPC concentrations.
The benthic macroinvertebrate community results were reviewed and bioturbation
depths were evaluated. Bioturbation is the movement or alteration of sediment particles
or porewater mediated by organisms. Bioturbation is a broadly defined term that
includes several distinct processes (including bioadvection, biodiffusion, and
bioirrigation) that influence sediment properties. Bioadvection is the nonrandom,
generally vertical flux of particles due to biological activity such as feeding and burrow
construction or maintenance. Biodiffusion is the vertical and horizontal transport of
materials, including contaminants, through the sediment column as a result of biological
activity. Bioirrigation is the movement of water and solutes within and out of the
sediment column due to active or passive flushing of infaunal burrows. The depth to
which organisms will bioturbate depends on behaviors of the specific organisms and the
characteristics of the substrate. The roles in bioturbation of the dominant groups
described above are discussed in more detail below.
The tubificid worms are most commonly found in soft sediments that are rich in organic
matter. As lakes become eutrophic and DO concentrations decrease, tubificid
oligochaetes tend to replace other benthic animals due to their tolerance for these
conditions (Soil & Water Conservation Society of Metro Halifax, 2008). None of the
oligochaete worms identified from OU-2 have a designated habit classification;
however, oligochaetes are generally expected to be important freshwater bioturbators
(Barbour et al., 1999).
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Members of the chironomid family are classified as burrowers (Barbour et al., 1999).
Chironomids are often the only insects found in lake sediments of the profundal zone
where hypoxic (oxygen concentrations less than 3 mg/L) and even anoxic conditions
sometimes occur (Rasmussen, 1996). The larvae and pupae of most species occurring
in low-oxygen sediments construct burrows and fixed tubes of sediments held together
with silky secretions. Tube and burrow dwellers can ventilate their tubes with fresh
water by dorso-ventral undulations of the body, thereby facilitating gas exchange during
times of low ambient oxygen and resulting in bioadvection and bioirrigation.
The benthic macroinvertebrates appear to be a freshwater or perhaps an oligohaline
system. Freshwater systems are less well-understood than estuarine systems with
respect to bioturbation depths, but are largely expected to be confined to the uppermost
6 inches (i.e., 15 cm) of the sediment column.
Additional aquatic invertebrates (various crayfish species, grass shrimp, and blue crab)
were encountered during the 1994 ecological studies. Mayflies were also collected in
1994. The benthic invertebrate community of OU-2 exhibited some evidence of stress
(lower diversity and abundance, and chetal aberrations in many oligochaetes) based on
limited comparisons with a reference area, Hatchetigbee Lake, that may in part be
attributable to the presence of COPCs. Another important factor to recognize in
characterizing the benthic invertebrate community of OU-2 is that limnological
conditions in the deeper portions of the Basin appear to be unfavorable to aerobically
respiring organisms.
Fish
The Lower Tombigbee River drainage has 131 documented fish species (Mettee et al.,
1996). Approximately 60 of these species are expected to occur in OU-2 or the
immediate vicinity based on habitat preferences, as documented in Table 3-2 of the
2011 Rl Report. The presence of 41 of the expected species has been confirmed, and
approximately 30 to 35 species appear to be relatively abundant. The location of OU-2
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in the Lower Tombigbee River Basin near the Mobile River Basin (two of the most
diverse river systems in Alabama) accounts for the high species diversity in OU-2.
Habitat diversity within OU-2 (deepwater habitat, shallows, large woody debris,
permanently and semi-permanently flooded wetlands, and floodplains) and abundant
food sources further support the species diversity observed at OU-2. Fish were
collected in 1986, 1991, 1994, 1995, 2001, 2003, 2005, 2006, and 2008. Fish tissue
data are summarized in Tables 10 and 11. The main objective offish sampling activities
in OU-2 has been to obtain tissues for COPC analyses. The fish community of OU-2
appears to be typical of similar environments throughout the Eastern Gulf Coastal Plain,
considering the gear used, level of effort, and the prevailing sampling conditions. The
only species that is usually common in such habitats that has not been observed is the
bowfin (Amia calva). The OU-2 fish community includes certain euryhaline fishes (e.g.,
least killifish [Heterandria formosa], Atlantic needlefish [Strongylura marina], and
hogchoker [Trinectes maculatus]).
The trends in fish tissue concentrations over time are summarized as follows:
• Mercury concentrations in upper trophic level fish increased from 2006 to 2008,
likely due to drought conditions that limited surface water exchange with the
Tombigbee River during this time.
• HCB concentrations in the upper and lower trophic level fish have decreased
over time. No middle trophic level fish sampled from multiple years are available
for historical trend comparison.
• DDTR concentrations in the upper and lower trophic level fish have decreased
over time. No middle trophic level fish sampled from multiple years are available
for historical trend comparison.
Terrestrial and Semi-Aquatic Vertebrates (Wildlife)
Faunal lists documenting occurrence and relative abundance of terrestrial and semi-
aquatic vertebrates were presented in Table 3-3 of the 2011 Rl Report. These faunal
lists were updated throughout the field investigations at OU-2, in particular the
annotations regarding confirmed presence in the area. Many of the strictly terrestrial
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vertebrates (e.g., some reptiles, most mammals) probably occur in the floodplain area of
OU-2 only as dry-season transients.
The available information on tetrapod vertebrates in OU-2 is generally observational
and limited, since minimal standardized quantitative sampling was performed.
Nevertheless, it provides a basis for a general qualitative description of the higher
vertebrate communities in the study area. The presence of at least 12 types of
amphibians, 17 types of reptiles, 58 types of birds, and 16 types of mammals in OU-2
have been confirmed directly through observation or indirectly through scat and sign.
Threatened and Endangered Species
The EPA contacted the USFWS, Alabama Ecological Services Field Office and
requested an updated list of endangered and threatened species and critical habitat for
the Olin OU-2 Site. USFWS reviewed the information and provided the following list of
species in accordance with the Fish and Wildlife Coordination Act (48 Stat. 401, as
amended; 16 U.S.C. et seq.), the Endangered Species Act (ESA) of 1973 (87 Stat. 884,
as amended: 16 U.S.C. 1531 et seq.), the Bald and Golden Eagle Protection Act of
1940, as amended (16 U.S.C. § 668-668d) (BGEPA), and the Marine Mammal
Protection Act of 1972 (16 U.S.C. § 1361 et seq.). The following federally listed species
may occur within the vicinity of the Olin OU-2 Superfund Site in Washington County.
Alabama:
• Alabama red-bellied turtle, Pseudemys alabamensis - Endangered
• Alabama sturgeon, Scaphirhyncus suttkusi - Endangered, Critical Habitat in
Alabama River
• Bald eagle, Haliaeetus leucocephalus - BGEPA
• Black pine snake, Pituophis melanoleucus lodingi - Candidate
• Gopher tortoise, Gopherus polyphemus - Threatened
• Gulf sturgeon, Acipenser oxyrinchus desotoi - Threatened
• Louisiana quillwort, Isoetes louisianensis - Endangered
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• West Indian manatee, Trichechus manatus - MMPA
• Wood stork, Mycteria americana - Endangered
Complete Exposure Pathways
The identification of complete and potentially complete exposure pathways is an
important step in the development of a CSM (USEPA, 1997). The selection of endpoint
organisms for evaluation in the BERA is based on the identified exposure pathways.
Varying exposure to COPCs in the ecosystem is expected due to differences in habitat,
behavior, and life cycles between different species. For example, aquatic organisms,
such as fish and aquatic invertebrates, often have more exposure to COPCs in the
water column or through the aquatic food web than to COPCs in the sediments. Benthic
organisms often have higher exposures from direct contact with sediments than
organisms that live in the water column. Mammals, birds, amphibians, and reptiles that
live in and/or forage in OU-2 also may be exposed to COPCs in the surface water,
sediment, and prey. Potential exposure routes and receptors are summarized in the
CSM for ecological receptors, which is presented in Figure 8. A generalized food web
model and a Site-specific food web model (Figures 22 and 23, respectively) are also
presented to show the relationship between the different levels of the food chain.
No barriers exist to prevent potential exposure to COPCs for ecological receptors on
and adjacent to OU-2 because OU-2 and adjacent land consist mainly of forests and
other undeveloped lands. Therefore, potential ecological receptors are present along
and within OU-2. These ecological receptors include aquatic organisms residing in OU-
2, wildlife using OU-2 as a source of food and drinking water, and plant and other
terrestrial organisms in floodplain soil areas.
Complete exposure pathways identified for aquatic organisms (e.g., benthic
macroinvertebrates and fish) residing within the Basin include dermal contact with
surface water and sediments, ingestion of surface water and sediments, and ingestion
of prey organisms that may bioaccumulate COPCs. Complete pathways identified for
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semi-aquatic and terrestrial wildlife using OU-2 as a source of food and drinking water
include the incidental ingestion of surface soil, dermal contact with surface soil,
inhalation of volatile emissions (qualitative assessment only), ingestion of plants and
prey organisms that may bioaccumulate COPCs, and dermal contact with subsurface
soil by burrowing species. Table 27 presents the summary for the ecological exposure
pathways.
The detailed and updated ERA used in selecting the remedy for this Site incorporates
the most recent data and further quantifies the exposure and risk to the receptors for
each pathway. A variety of comprehensive biological field assessments were
conducted for OU-2. These assessments provide sufficient evidence and information to
estimate the exposure to biota in the assessment area. Risk comparisons were
performed for constituents in surface water, sediment, floodplain soil, and tissue
residues from OU-2.
2.7.2.3 Ecological Effects Assessment and Measurement Endpoints
The ERA defines and addresses issues based on potentially complete exposure
pathways and ecological effects. The CSM identifies the relationships between potential
exposures and potential exposure effects. Defining ecological concerns during the ERA
involves identifying toxic mechanisms, characterizing potential receptors, and estimating
exposure and evaluating the resulting potential ecological effects of exposure.
Endpoints were defined to evaluate potential ecological effects. Consistent with the EPA
guidance, two types of endpoints were identified. Assessment endpoints are ecological
values to be protected (e.g., maintenance of a viable community of aquatic organisms,
such as fish inhabiting the Basin). Because direct measurement of these assessment
endpoints is often not practical, measurement endpoints are used to evaluate the
assessment endpoints. A measurement endpoint is a measurable ecological
characteristic and/or response to a stressor (e.g., bioassays measuring survival or
growth of organisms, comparison of modeled doses to toxicity reference values based
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on chronic effects). Assessment endpoints are the principal focus of the ERA and
provide the link between the measurement endpoints and risk management decisions.
Assessment endpoints are characteristic of the ecological system or its individual
components of concern being evaluated. The definition (or specification) of an
assessment endpoint should include a subject (e.g., the guild, habitat, or species of
interest) and a characteristic of that subject (e.g., survivorship and fecundity). The
specification of the assessment endpoint should also describe how the endpoint
represents functions important to the health and sustainability of the ecosystem (i.e.,
biological relevance). Assessment endpoints should consider and reflect societal values
and should allow prediction and/or measurement (albeit not always direct
measurement). Finally, the assessment endpoints should be susceptible to the
stressors being evaluated.
On December 7, 2009, the EPA provided a presentation to Olin and its support
contractor AM EC addressing the ERA approach, including the assessment endpoints
that should be addressed (USEPA, 2009). This presentation listed assessment
endpoints for both terrestrial and aquatic species, and provided the EPA's requirements
regarding the representativeness of each species and the dietary inputs and area use
factors (AUFs) that should be used in the ERA. A second presentation by the EPA to
Olin and AMEC on December 8, 2009, specified which historical and current data
should be used in the ERA (USEPA, 2009). This ERA was performed in accordance
with the EPA's required assessment endpoints and data use specifications. The ERA
assessment endpoints were further refined and selected based on the ecology and the
COPCs present. Based on this information, the following assessment endpoints were
identified for OU-2:
• Assessment Endpoint 1: Protection of the Long-term Health and Reproductive
Success of the Benthic Macroinvertebrate Community
• Assessment Endpoint 2: Protection of the Long-term Health and Reproductive
Success of the Fish Community
• Assessment Endpoint 3: Protection of the Long-term Health and Reproductive
Success of the Soil Invertebrates in Floodplain Soils
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• Assessment Endpoint 4: Protection of the Long-term Health and Reproductive
Success of Insectivorous Aquatic Mammals
• Assessment Endpoint 5: Protection of the Long-term Health and Reproductive
Success of Carnivorous Aquatic Mammals
• Assessment Endpoint 6: Protection of the Long-term Health and Reproductive
Success of Insectivorous Aquatic Birds
• Assessment Endpoint 7: Protection of the Long-term Health and Reproductive
Success of Piscivorous Aquatic Birds
• Assessment Endpoint 8: Protection of the Long-term Health and Reproductive
Success of Omnivorous Aquatic Birds
• Assessment Endpoint 9: Protection of the Long-term Health and Reproductive
Success of Carnivorous Aquatic Reptiles
• Assessment Endpoint 10: Protection of the Long-term Health and Reproductive
Success of Insectivorous Terrestrial Mammals
• Assessment Endpoint 11: Protection of the Long-term Health and Reproductive
Success of Omnivorous Terrestrial Mammals
• Assessment Endpoint 12: Protection of the Long-term Health and Reproductive
Success of Herbivorous Terrestrial Mammals
• Assessment Endpoint 13: Protection of the Long-term Health and Reproductive
Success of Insectivorous Terrestrial Birds
Assessment Endpoints 1, 2 and 3 were addressed as part of the SLERA. Based on the
results of the SLERA, the EPA determined that unacceptable risk exists to Endpoint 2
(fish community) based on levels of mercury and DDTR in fish tissue. Though this
endpoint was not further addressed in the ERA, sediment and fish tissue remedial goals
(RGs) were developed for protection offish communities based on the SLERA results.
These RGs are discussed further in the RAO section of this ROD. The ERA focused on
Assessment Endpoints 4 to 13.
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Corresponding Measurement Endpoints
Each assessment endpoint was evaluated using measurement endpoints. These
measurement endpoints included comparisons among environmental media
concentrations associated with estimates of potential toxicity, and comparisons between
doses or exposures measured or modeled in biotic receptors to toxicologically relevant
doses or tissue concentrations, dependent on the corresponding assessment endpoint.
The EPCs detected in various media at OU-2 are presented in Table 26.
Each measurement endpoint was selected based on Site knowledge, the generalized
food web model, information regarding the toxicity of the constituents of concern, and
stakeholder consensus. The measurement endpoints constitute a suite of ecotoxicity
study concentrations with associated effects, semi-quantitative comparisons to effect
and no effect concentrations, and quantitative estimates of potential exposures and
potential concerns that were used to assess risks. A summary of the selected
assessment and measurement endpoints is presented in Table 27.
Assessment endpoints for the various mammals and birds studied (Assessment
Endpoints 4 through 13) were evaluated using a quantitative approach. For the
purposes of this ERA, a quantitative approach analyzes biota exposures through food
web modeling in addition to direct contact uptake. An estimated exposure dose for each
COPC is modeled by using EPCs for site media and prey species tissue. This
calculated dose will then be divided by applicable TRVs to assess the likelihood of
adverse health effects.
Overview of Quantitative Multi-Pathway Risk Estimation for Assessment
Endpoints 4 through 13
Assessment Endpoints 4 through 13 were evaluated using current standard practices in
the ERA for estimating potential risks through the estimation of food chain and
environmental media exposure for mercury, methylmercury, HCB, and DDTR. The
following discussions outline the approach for the risk assessment, including toxicity
data, modeling studies and dose conversions, EPCs, study design, weight of evidence,
data analysis summary, and risk characterization. Discussions for Assessment
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Endpoints 4 through 13, organized by assessment endpoint number, provide
descriptions of exposure, discuss associated measurement endpoint(s), and present
information regarding the potential for effects on associated receptors.
Assessment Endpoint 4: Protection of the Long-Term Health and Reproductive Success
of Insectivorous Aquatic Mammals
Little Brown Bat
Assessment Endpoint 4 addresses the potential risk to insectivorous aquatic mammals
residing and foraging within OU-2. This assessment endpoint considers effects on
mammals relying on insects as the primary dietary item. The little brown bat (Myotis
lucifugus) was selected as a conservative representative species of insectivorous
aquatic mammals because its dietary intake can consist entirely of insects. The little
brown bat's diet, for the purpose of this risk assessment, consists of 100 percent flying
insects. The little brown bat is also representative of an aerial mammal with a home
range larger than the available habitat at OU-2, therefore only using the site area
approximately one-quarter of the time. The little brown bat exposure model was
supported by the collection of flying insects in July 2010. This assessment endpoint also
addresses other aerial insectivorous mammals, including other species of bats.
Because the NOAEL-based HI exceeded the threshold value of 1 and the LOAEL-
based HI was less than 1, the potential for risk for the little brown bat lies between the
no observed adverse effects level and the lowest observed adverse effects level. The
function, health, and reproductive success for the little brown bat (insectivorous aquatic
mammal), appears to have a potential for adverse effects from exposure to COPC
concentrations in OU-2.
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Assessment Endpoint 5: Protection of the Long-Term Health and
Reproductive Success of Carnivorous Aquatic Mammals
Mink and River Otter
Assessment Endpoint 5 addresses the potential risk to carnivorous aquatic mammals
residing and foraging in OU-2 habitat. Carnivorous mammals may use pools and river
edge habitats. In particular, aquatic carnivores typically feed on fish and crustaceans
(i.e., crayfish) from pool and run habitats. The river otter was selected as a
representative species of carnivorous aquatic mammals for quantification of a diet
based on 85 percent fish (75 percent forage fish and 10 percent predatory fish), 10
percent amphibians, and 5 percent crayfish. The river otter is representative of a
carnivorous aquatic mammal with a large home range (approximately 870 acres). This
area is significantly larger than the available OU-2 habitat, indicating the river otter's
area use factor of OU-2 is only approximately 0.09 (i.e., the river otter is using OU-2
habitat only 9 percent of the time). The river otter exposure model was supported by the
collection of forage fish, predatory fish, amphibians, and crayfish.
The NOAEL-based HI for the river otter was 0.20 with contributions of mercury (0.0018),
methylmercury (0.086), DDTR (0.083), and HCB (0.029). NOAEL-based His for the river
otter were less than the threshold value of 1. Thus, river otter (large carnivorous aquatic
mammals) are considered unlikely to be adversely affected by mercury, methylmercury,
DDTR, and HCB in OU-2.
The mink was also selected as a representative species of carnivorous aquatic
mammals for quantification of a diet based not only on aquatic species, but also on
mammals and birds that reside in or near aquatic habitat. The mink's dietary makeup
consists of 40 percent aquatic mammals/birds, 25 percent amphibians, 10 percent
crayfish, 5 percent forage fish, and 20 percent predatory fish. The mink represents a
carnivorous aquatic mammal that would spend nearly all of its time at OU-2 habitat. It
has a relatively small home range (approximately 1.34 miles of shoreline), which is
essentially the same as the available shoreline of OU-2. The mink exposure model was
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supported by the collection of amphibians, crayfish, forage fish, predatory fish, and birds
(little blue herons).
The NOAEL-based HI for the mink was 5.4 with contributions of mercury (1.8),
methylmercury (1.3), DDTR(1.2), and HCB (1.1). NOAEL-based His for the mink
exceeded the threshold value of 1 for mercury, methylmercury, and HCB with potential
risk being derived approximately equally from mercury, methylmercury, DDTR, and
HCB. The mercury and HCB HQs for the mink were driven only by the incidental
ingestion of sediments (assumed to be 9 percent). The methylmercury and DDTR HQs
were driven equally by aquatic vertebrate prey items and predatory fish. Because
NOAEL-based HQs exceeded the threshold value of 1 for mercury, methylmercury,
DDTR, and HCB, further assessment in the form of LOAEL-based His was performed
for these chemicals.
The LOAEL-based HI for the mink was 4.2 with contributions of mercury (1.8),
methylmercury (0.64), DDTR (0.62), and HCB (1.1). LOAEL-based HQs for the mink
exceeded the threshold value of 1 for mercury and HCB with the majority of potential
risk being derived from mercury. HQs greater than 1 (i.e., mercury and HCB) were
driven by sediment ingestion (assumed to be 9 percent incidental ingestion).
Mercury and HCB concentrations have the potential to impair the function, health, or
reproductive success of the mink (small carnivorous terrestrial mammals) with relatively
small home ranges. The representativeness of this Rl for current site conditions is fairly
uncertain due to the reliance on 1994 vertebrate prey data and a conservative
percentage of incidental sediment ingestion.
Assessment Endpoint6: Protection of the Long-Term Health and Reproductive Success
of Insectivorous Aquatic Birds
Pied-billed Grebe
Assessment Endpoint 6 addresses the potential risk to insectivorous aquatic birds
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residing and foraging in OU-2 habitats. Insectivorous aquatic birds, represented by the
pied-billed grebe, typically feed on fish, crustaceans, and aquatic insects by diving
under water for food, whether in open water or among vegetation. The pied-billed grebe
(.Podilymbus podiceps) represents a species whose diet is approximately 60 percent
aquatic insects, 20 percent forage fish, and 20 percent crayfish. In addition, the home
range of a pied-billed grebe is relatively small, only 3.3 acres, compared to the open
water area of OU-2, which is 80 acres. This indicates the pied-billed grebe is
representative of a receptor that could spend all of its time within OU-2 habitat. The
pied-billed grebe exposure model was supported by the collection of forage fish and
crayfish. Aquatic insect concentrations were estimated using current sediment
concentrations and a site-specific BAF from historical data.
The NOAEL-based HI for the pied-billed grebe was 11 with contributions of mercury
(1.6), methylmercury (1.2), DDTR (8.0), and HCB (0.31). NOAEL-based HQs for the
pied-billed grebe exceeded the threshold value of 1 for mercury, methylmercury, and
DDTR with the majority of potential risk being derived from DDTR. HQs were driven by
ingestion of forage fish for methylmercury (assumed to be from bluegill and silverside
samples collected in 2008), ingestion of aquatic insects for DDTR, and incidental
ingestion of sediments for mercury (assumed to be from sediment samples collected in
2008 and 2009). The mercury HQ was driven by incidental ingestion of sediments.
Methylmercury HQs were driven by ingestion of forage fish (bluegill and silverside
samples). Because NOAEL based HQs exceeded the threshold value of 1 for mercury,
methylmercury, and DDTR, further assessment in the form of a LOAEL-based HI was
performed for these chemicals.
The LOAEL-based HI for the pied-billed grebe was 8.5 with contributions of mercury
(0.78), methylmercury (1.2), and DDTR (6.4). The LOAEL-based HQ for the pied-billed
grebe exceeded the threshold value of 1 for methylmercury and DDTR. His were driven
primarily by the ingestion of forage fish for methylmercury and aquatic insects for
DDTR. The pied-billed grebe was considered to have a small home range (completely
within OU-2) and a diet consisting primarily of aquatic insects, with lesser amounts of
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forage fish and crayfish. The pied-billed grebe was assumed to use the Site for all of its
dietary needs because of the grebe's small home range. These assumptions accounted
for the exceedance of the threshold value of 1 for mercury, methylmercury, and DDTR
for the NOAEL-based calculation, while the NOAEL HQ for HCB was less than the
threshold value of 1.
Methylmercury and DDTR concentrations have the potential to impair the function,
health, or reproductive success of the pied-billed grebe (insectivorous aquatic birds)
with relatively small home ranges. The accuracy of the DDTR HQ was considered
somewhat uncertain due to the reliance on estimated aquatic insect data.
Assessment Endpoint 7: Protection of The Long-Term Health and Reproductive
Success of Piscivorous Aquatic Birds
Belted Kingfisher
Piscivorous aquatic birds are represented by the belted kingfisher, little blue heron, and
great blue heron for the purposes of risk quantification for Assessment Endpoint 7.
Assessment Endpoint 7 addresses the potential risk to piscivorous aquatic birds
residing and foraging in OU-2. Piscivorous birds may use pool, river, or lake-edge
habitats as foraging and bedding areas, and piscivorous birds may feed on fish caught
from pool and run habitats.
The belted kingfisher (Ceryle alcyon) was selected as one of the representative species
of piscivorous aquatic birds for quantification of an aquatic piscivore since this species
is a year-round resident in Alabama. The belted kingfisher exposure model was
supported by the collection of forage fish from the Basin. The belted kingfishers were
evaluated using two different exposure scenarios to account for the range of exposure
parameters and site conditions that are present in OU-2. The first exposure scenario
assumes that the belted kingfisher forages exclusively on forage fish obtained from the
Basin. This is the recommended exposure scenario by the EPA, and it is consistent with
USEPA's Wildlife Exposure Factors Handbook (WEFH) (1993c). In the second
exposure scenario, the dietary composition of the belted kingfisher was adjusted to
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reflect a more diverse diet that includes forage fish (51 percent), amphibians (25
percent), aquatic insects (19 percent), and crayfish (5 percent). This dietary makeup
was obtained from the WEFH for belted kingfishers in a lake-type environment. The
area use factor was also set to 0.5 representing a kingfisher that forages 50 percent of
the time within OU-2 and 50 percent of the time outside of OU-2. The two scenarios are
presented to provide a range of potential risk values.
The NOAEL-based HI for the first exposure scenario for the belted kingfisher was 11
with contributions of mercury (0.060), methylmercury (7.0), DDTR (3.9), and HCB
(0.12). NOAEL-based HQs for the belted kingfisher were greater than the threshold
value of 1 for methylmercury and DDTR. Potential risk for the belted kingfisher was
driven by consumption of forage fish (which was assumed to be 100 percent of the
belted kingfisher's diet). The NOAEL-based methylmercury TRV for avian receptors
could not be identified in scientific literature, so the LOAEL based methylmercury TRV
was used as the NOAEL-based TRV in the risk assessment. Because NOAEL based
His exceeded the threshold value of 1 for methylmercury and DDTR, further
assessment in the form of LOAEL-based HI was performed for these chemicals. The
LOAEL-based HI for the first exposure scenario for the belted kingfisher was 10 with
contributions of methylmercury (7.0) and DDTR (3.2). LOAEL-based His for the belted
kingfisher exceeded the threshold value of 1 for methylmercury and DDTR with the
majority of potential risk being derived from methylmercury. His were driven by
ingestion of forage fish (which was assumed to be 100 percent of the belted kingfisher's
diet).
The NOAEL-based HI for the second exposure scenario for the belted kingfisher was
4.8 with contributions of mercury (0.054), methylmercury (2.0), DDTR (2.7), and HCB
(0.084). NOAEL-based HQs for the belted kingfisher were greater than the threshold
value of 1 for methylmercury and DDTR. Potential risk for the belted kingfisher was
driven by consumption of forage fish for methylmercury (which was assumed to be 51
percent of the belted kingfisher's diet) and consumption of aquatic insects for DDTR
(which was assumed to be 19 percent of the belted kingfisher's diet). The NOAEL-
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based methylmercury TRV for avian receptors could not be identified in scientific
literature, so the LOAEL-based methylmercury TRV was used as the NOAEL-based
TRV in the risk assessment. Because NOAEL-based His exceeded the threshold value
of 1 for methylmercury and DDTR, further assessment in the form of LOAEL-based HI
was performed for these chemicals. The LOAEL-based HI for the second exposure
scenario for the belted kingfisher was 4.2 with contributions of methylmercury (2.0) and
DDTR (2.2). LOAEL-based His for the belted kingfisher exceeded the threshold value of
1 for methylmercury and DDTR with potential risk being derived from methylmercury
and DDTR at approximately the same levels. Methylmercury HQs were driven by
ingestion of forage fish (which was assumed to be 51 percent of the belted kingfisher's
diet) and DDTR HQs were driven by the ingestion of aquatic insects (which was
assumed to be 19 percent of the belted kingfisher's diet).
Methylmercury and DDTR concentrations have the potential to impair the function,
health, or reproductive success of the belted kingfisher (piscivorous aquatic birds) with
relatively high fish consumption rates.
Although a conclusion of potential risk must be stated based on the NOAEL-based HI
exceeding 1, there is uncertainty related to the NOAEL-based and LOAEL-based HI
calculation for the belted kingfisher. No nesting habitat is available in OU-2 for belted
kingfishers, so nesting belted kingfishers feeding in OU-2 must live along the
Tombigbee River. The maximum exposure scenario for the belted kingfisher feeding
100 percent of the time in OU-2 may cause an overestimation of potential risk for this
receptor during nesting season. However, belted kingfishers only utilize nest burrows
during the nesting season, and utilize trees as overnight perches the remainder of the
year. Therefore, an assumption of 100% feeding in OU-2 may be realistic during non-
nesting seasons.
Little Blue Heron
The little blue heron (Egretta caerula) was selected as one of the representative species
of piscivorous aquatic birds. This receptor was selected to represent a diet that is
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composed of 75 percent forage fish and 25 percent aquatic insects. The little blue heron
is also a year-round resident in Alabama and has been observed in OU-2 habitat. The
little blue heron exposure model was supported by the collection of forage fish and
aquatic insects.
The NOAEL-based HI for the little blue heron was 10.2 with contributions of mercury
(1.5), methylmercury (3.7), DDTR (4.9), and HCB (0.20). The NOAEL-based HQs for
the little blue heron were greater than the threshold value of 1 for mercury,
methylmercury, and DDTR. Potential risk for the little blue heron was driven by
consumption of forage fish for methylmercury and DDTR, which represents 75 percent
of the little blue heron's diet, and consumption of aquatic insects for DDTR, which
represents 25 percent of the little blue heron's diet. The mercury HQ was driven by
incidental ingestion of sediments. The NOAEL-based methylmercury TRV for avian
receptors could not be identified in scientific literature, so the LOAEL-based
methylmercury TRV was used as the NOAEL-based TRV in the risk assessment.
Because NOAEL-based His exceeded the threshold value of 1 for mercury,
methylmercury, and DDTR, further assessment in the form of a LOAEL-based HI was
performed for these chemicals.
The LOAEL-based HI for the little blue heron was 8.4 with contributions of mercury
(0.75), methylmercury (3.7), and DDTR (3.9). LOAEL-based HQs for the little blue heron
exceeded the threshold value of 1 for methylmercury and DDTR with potential risk being
derived from methylmercury and DDTR at approximately the same levels. The HQs
were driven by ingestion of forage fish for methylmercury (which was assumed to be 75
percent of the little blue heron's diet) and DDTR and the ingestion of aquatic insects for
DDTR (which was assumed to be 25 percent of the little blue heron's diet).
Methylmercury and DDTR concentrations have the potential to impair the function,
health, or reproductive success of the little blue heron (piscivorous aquatic birds) with
diets consisting of forage fish and aquatic insects.
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Great Blue Heron
The great blue heron (Herodia ardea) was also selected as a representative species of
piscivorous aquatic bird. In addition to forage fish (50 percent of the great blue heron
diet), its dietary makeup consists of 35 percent predatory fish, 10 percent amphibians,
and 5 percent aquatic insects. These additional species represent consumption of
sediment-dwelling organisms by piscivorous aquatic birds. The great blue heron is also
a year-round resident in Alabama, with a home range (approximately 1.1 miles of
shoreline) smaller than the available habitat at OU-2, indicating it could spend nearly all
of its time in OU-2 habitat. The great blue heron exposure model was supported by the
collection of forage fish, predatory fish, amphibians, and aquatic insects.
The NOAEL-based HI for the great blue heron was 6.0 with contributions of mercury
(0.91), methylmercury (3.5), DDTR (1.5), and HCB (0.089). The NOAEL-based HQs for
the great blue heron were greater than the threshold value of 1 for methylmercury and
DDTR. Potential risk for the great blue heron was driven by consumption of forage fish
and predatory fish for methylmercury, which combined to represent 85 percent of the
great blue heron's diet and forage fish for DDTR, which represents 50 percent of the
great blue heron's diet. The NOAEL-based methylmercury TRV for avian receptors
could not be identified in scientific literature, so the LOAEL-based methylmercury TRV
was used as the NOAEL-based TRV in the risk assessment. Because NOAEL based
His exceeded the threshold value of 1 for methylmercury and DDTR, further
assessment in the form of LOAEL-based His was performed for these chemicals. The
LOAEL-based HI for the great blue heron was 4.7 with contributions of methylmercury
(3.5) and DDTR (1.2). LOAEL-based HQs for the great blue heron exceeded the
threshold value of 1 for methylmercury and DDTR. The methylmercury HQ was driven
by ingestion of forage fish and predatory fish. The DDTR HQ was driven by the
ingestion of forage fish.
Methylmercury and DDTR concentrations have the potential to impair the function,
health, or reproductive success of the great blue heron or other piscivorous aquatic
birds with diets consisting of forage fish, predatory fish, and other sediment dwelling
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organisms. There is uncertainty related to the NOAEL-based and LOAEL-based HI
calculation for the great blue heron. The dataset used to calculate the EPC for DDTR in
fish was collected in 2001. Concentrations in upper trophic fish tissue may have
declined in nine years. In addition, a conversion factor for DDTR was used to calculate
whole body fish tissue concentrations in predatory fish from fish fillet tissue
concentrations. In comparison to the other piscivorous birds evaluated in this risk
assessment, the great blue heron had a significantly higher percentage of predatory fish
in its diet—35 percent compared to 0 percent for both the belted kingfisher and little
blue heron. The great blue heron His were greater than 1 primarily due to the predatory
fish portion of its diet (requiring conversion from fillet concentrations for DDTR).
Assessment Endpoint 8: Protection of the Long-Term Health and Reproductive Success
of Omnivorous Aquatic Birds
Wood Duck
Assessment Endpoint 8 addresses the potential risk to omnivorous aquatic birds
residing and foraging in OU-2 habitats. Omnivorous birds, such as the wood duck (Aix
sponsa), will nest next to water, often using trees or nest boxes. This receptor feeds by
picking or "dabbling" at the surface, and frequently dives for submerged food items (i.e.,
vegetation). The wood duck was selected as the representative species of omnivorous
aquatic birds at OU-2 for quantification of an aquatic omnivore with a dietary makeup of
75 percent vegetation and 25 percent insects. The wood duck's home range is less than
the available open water habitat at the Basin, indicating this receptor could spend all of
its time at the Site.
The wood duck exposure model was supported by the collection of insect (i.e., crawling
insects, flying insects, and spiders) and vegetation data. Site-specific aquatic vegetation
data are not available for use in the exposure model because no aquatic vegetation was
available for collection in OU-2. Therefore, terrestrial vegetation data were used in the
exposure model for the wood duck.
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The NOAEL-based HI for the wood duck was 1.0 with contributions of mercury (0.71),
methylmercury (0.15), DDTR (0.12), and HCB (0.023). The individual NOAEL-based
HQs for the wood duck did not exceed the threshold value of 1. However, the NOAEL-
based HI for the wood duck was equal to the threshold value of 1. The HI was driven by
the incidental ingestion of sediments (assumed to be 3.3 percent). Mercury provided the
greatest magnitude of the NOAEL-based HI with a HQ of 0.71. Because the NOAEL-
based HI was equal to the threshold value of 1, further assessment in the form of a
LOAEL-based HI was performed. The LOAEL-based HI for the wood duck was 0.63,
which is below the threshold value of 1.
There is potential for the impairment of the function, health, or reproductive success of
the wood duck (omnivorous aquatic birds) with small home ranges residing and foraging
in OU-2 based on the NOAEL-based HI.
Assessment Endpoint 9: Protection of the Long-Term Health and Reproductive Success
of Carnivorous Aquatic Reptiles
American Alligator
Assessment Endpoint 9 addresses the potential risk to carnivorous aquatic reptiles
residing and foraging within OU-2. This assessment endpoint considers effects on
reptiles relying on fish, small mammals, birds, and amphibians also foraging or residing
within OU-2 habitats. The American alligator {Alligator mississippiensis) was selected as
a conservative representative species of carnivorous aquatic reptile because its dietary
intake includes fish (60 percent predatory fish, 30 percent forage fish), 5 percent
amphibians, and 5 percent small mammals and birds. The American alligator also
represents a large reptile whose home range is smaller than the OU-2 habitat, and
therefore has an area use factor of 1, indicating it could spend all of its time with OU-2
habitat. The American alligator exposure model was supported by the collection of
predatory fish, forage fish, amphibians, small mammals, and birds
The NOAEL-based HI for the American alligator was 0.011 with contributions of mercury
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(0.0037), methylmercury (0.0025), and DDTR (0.0047). Potential risk was not
quantifiable for HCB as no TRVs were available for reptiles specifically for HCB. The
NOAEL-based HI for the American alligator was less than the threshold value of 1.
There is little potential for impairment of the function, health, or reproductive success of
the American alligator. It is not anticipated that the American alligator (carnivorous
aquatic reptiles) will experience adverse effects due to exposure to COPCs while
residing or foraging in OU-2.
Assessment Endpoint 10: Protection of the Long-Term Health and Reproductive
Success of Insectivorous Terrestrial Mammals
Short-Tailed Shrew
Assessment Endpoint 10 addresses the potential risk to insectivorous terrestrial
mammals residing and foraging within OU-2. This assessment endpoint considers
effects on mammals relying on terrestrial invertebrates. The short-tailed shrew (Blarina
blevicada) was selected as a conservative representative species of insectivorous
terrestrial mammals because its dietary intake is entirely (100 percent) composed of
terrestrial insects and spiders. The short-tailed shrew represents a terrestrial mammal
with a home range smaller than the available habitat at OU-2, indicating it could spend
all of its time within OU-2. The short-tailed shrew exposure model was supported by the
collection of crawling insects and spiders.
The NOAEL-based HI for the short-tailed shrew was 1.6 with contributions of mercury
(0.28), methylmercury (0.56), DDTR (0.78), and HCB (0.0036). The individual NOAEL-
based HQs for the short-tailed shrew did not exceed the threshold value of 1. However,
the NOAEL-based HI, which is derived by the sum of the NOAEL-based HQs, exceeded
the threshold value of 1. The HI was driven by the ingestion of insects and spiders.
Methylmercury and DDTR provided the greatest magnitude of the NOAEL-based HI
with HQs of 0.56 and 0.78, respectively. Because the NOAEL-based HI exceeded the
threshold value of 1, further assessment in the form of a LOAEL-based HI was
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performed. The LOAEL-based HI for the short-tailed shrew was 0.98, which is below the
threshold value of 1. The short-tailed shrew was considered to have a small home
range (completely within OU-2) and a diet consisting entirely of terrestrial insects and
spiders. These assumptions accounted for the NOAEL-based HI exceedance of the
threshold value of 1, while the individual HQs for mercury, methylmercury, DDTR, and
HCB were all less than the threshold value of 1.
There is potential for the impairment of the function, health, or reproductive success of
the short-tailed shrew (other insectivorous terrestrial mammals) with small home ranges
residing and foraging in OU-2 based on the NOAEL-based HI.
Assessment Endpoint 11: Protection of the Long-Term Health and Reproductive
Success of Omnivorous Terrestrial Mammals
Raccoon
Assessment Endpoint 11 addresses the potential risk to omnivorous terrestrial
mammals residing and foraging within OU-2. This assessment endpoint considers
effects on mammals relying on terrestrial insects, small mammals, birds, and vegetation
as primary dietary items. The raccoon (Procyon lotor) was selected as a conservative
representative species of omnivorous terrestrial mammals because its dietary intake
includes a variety of terrestrial prey items (40 percent terrestrial invertebrates, 40
percent terrestrial vertebrates) and vegetation (20 percent) and is found near virtually
every aquatic habitat. The raccoon represents mammalian receptors that spend
approximately half their time in OU-2 habitat, with an area use factor of 0.48. The
raccoon exposure model was supported by the collection of insects, small mammals,
birds, and vegetation.
The NOAEL-based HI for the raccoon was 0.30 with contributions of mercury (0.046),
methylmercury (0.13), DDTR (0.12), and HCB (0.0007). The NOAEL-based HI for the
raccoon was less than the threshold value of 1.
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There is little potential for impairment of the function, health, or reproductive success of
the raccoon. It is not anticipated that the raccoon and other omnivorous terrestrial
mammals will experience adverse effects due to exposure to COPCs while residing or
foraging in OU-2.
Assessment Endpoint 12: Protection of the Long-Term Health and Reproductive
Success of Herbivorous Terrestrial Mammals
Pine Vole
Assessment Endpoint 12 addresses the potential risk to herbivorous terrestrial
mammals residing and foraging within OU-2. This assessment endpoint considers
effects on mammals relying on terrestrial vegetation as the primary dietary item. The
pine vole (Microtus pinetorum) was selected as a conservative representative species of
herbivorous terrestrial mammals because its dietary intake consists entirely (100
percent) of terrestrial vegetation. The pine vole represents herbivorous mammals with
an area use factor of 1. The pine vole exposure model was supported by the collection
of terrestrial vegetation. This species served as a surrogate species for voles, moles,
mice, and rats residing in OU-2.
The NOAEL-based HI for the pine vole was 0.20 with contributions of mercury (0.054),
methylmercury (0.034), DDTR (0.11), and HCB (0.0016). The NOAEL-based HI for the
pine vole was less than the threshold value of 1.
There is little potential for impairment of the function, health, or reproductive success of
the pine vole. It is not anticipated that the pine vole and other herbivorous terrestrial
mammals will experience adverse effects due to exposure to COPCs while residing or
foraging in OU-2.
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Assessment Endpoint 13: Protection of the Long-Term Health and Reproductive
Success of Insectivorous Terrestrial Birds
Carolina Wren
Assessment Endpoint 13 addresses the potential risk to insectivorous terrestrial birds
residing and foraging within OU-2. This assessment endpoint considers effects on birds
relying heavily on terrestrial invertebrates as dietary items. The Carolina wren
('Thryothorus ludovicianus) was selected as a conservative representative species of
insectivorous terrestrial birds because its dietary intake is comprised entirely (100
percent) of terrestrial invertebrates. The Carolina wren represents an insectivorous bird
with an area use factor of 1, as its home range is smaller than the area of OU-2. The
Carolina wren model was supported by the collection of insects (i.e., crawling insects,
flying insects, and spiders).
The NOAEL-based HI for the Carolina wren was 5.2 with contributions of mercury (1.0),
methylmercury (2.4), DDTR (1.8), and HCB (0.022). NOAEL-based HQs for the
Carolina wren were equal to or exceeded the threshold value of 1 for mercury,
methylmercury, and DDTR with the highest potential risk being derived from
methylmercury. The NOAEL-based HQ for HCB did not exceed the threshold value of 1.
HQs were driven by the ingestion of insects. Because the NOAEL-based HQs exceeded
the threshold value of 1 for mercury, methylmercury and DDTR, further assessment in
the form of LOAEL-based HQs was performed for the Carolina wren.
The LOAEL-based HI for the Carolina wren was 4.3 with contributions of mercury
(0.50), methylmercury (2.4), and DDTR (1.4). The LOAEL-based HI for the Carolina
wren exceeded the threshold value of 1 with the methylmercury and DDTR HQs also
exceeding the threshold value of 1. HQs were driven by the ingestion of insects.
Mercury, methylmercury, and DDTR concentrations have the potential to impair the
function, health, or reproductive success of the Carolina wren and other insectivorous
terrestrial birds. Thus, insectivorous terrestrial birds residing or foraging in OU-2 appear
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to be at a level of potential concern based on the assumptions and calculations
performed in this ERA.
2.7.2.4 Ecological Risk Characterization
The ERA was performed to evaluate the potential for adverse effects associated with
mercury, methylmercury, DDTR, and HCB concentrations from various environmental
media at OU-2. Results from biological field investigations and extensive OU-2 sample
data were used to develop potential risk estimates.
NOAEL-based His for the river otter, the American alligator, the raccoon, and the pine
vole were less than the threshold value of 1, which indicates that the potential for these
receptors to experience adverse health effects is unlikely. The remaining receptors have
at least one COPC whose HQ exceeds the threshold value of 1 or the HI (i.e., the
summation of the HQs) was equal to or exceeded the threshold value of 1. The little
brown bat, the short-tailed shrew, and the wood duck have NOAEL-based His that are
equal to or exceed the threshold value of 1, but the LOAEL-based His are below the
threshold value of 1. COPCs with NOAEL-based and LOAEL-based HQs exceeding the
threshold value of 1 by pathway of concern and receptor for OU-2 are as follows:
• Mercury
o Incidental ingestion of sediments (mink: LOAEL HQ = 1.1)
• Methylmercury
o Ingestion of forage fish (pied-billed grebe (LOAEL HQ = 1.2), belted
kingfisher (LOAEL HQ = 2.0 to 7.0), little blue heron (LOAEL HQ = 3.7),
great blue heron (LOAEL HQ = 3.5))
o Ingestion of predatory fish (great blue heron: LOAEL HQ = 3.5)
o Ingestion of insects (Carolina wren: LOAEL HQ = 2.4)
• DDTR
o Ingestion of forage fish (belted kingfisher (LOAEL HQ = 2.2 to 3.2), little
blue heron (LOAEL HQ = 3.5), and great blue heron (LOAEL HQ = 1.4))
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o Ingestion of aquatic insects (pied-billed grebe (LOAEL HQ = 5.4), belted
kingfisher (LOAEL HQ = 2.2 to 3.2), and little blue heron (LOAEL HQ =
3.5))
o Ingestion of insects (Carolina wren: LOAEL HQ = 1.4)
• HCB
o Incidental ingestion of sediments (mink: LOAEL HQ = 1.1)
Several receptors had NOAEL-based HQs that exceeded the threshold value of 1 but
the LOAEL based HQs did not exceed the threshold value of 1. This indicates that these
receptors' potential risk lies between the NOAEL and the LOAEL. These receptors were
the mink for methylmercury; the pied-billed grebe for mercury; the little blue heron for
mercury; and the Carolina wren for mercury. There is a borderline potential for risk to
these receptors from the listed COCs.
The little brown bat, the short-tailed shrew, and the wood duck have NOAEL-based HI
values that are equal to or exceed the threshold value of 1, but the LOAEL-based HI
values are below the threshold value of 1. The individual HQs for mercury,
methylmercury, DDTR, and HCB were all less than the threshold value of 1, but the HI
exceeded the threshold value of 1, indicating the potential for risk.
As shown above, the risk assessment found risk to Carolina wren from methylmercury
and DDTR in insect tissue. The flying insects collected in 2010 and included in the risk
characterization typically had higher concentrations of site COPCs than the 2010
crawling insects and spiders that would be typically consumed by the Carolina wren.
Carolina wrens are primarily ground foragers and may not ingest significant amounts of
flying insects. The inclusion of flying insects for the Carolina wren increased the EPCs
for the site COPCs and may have overestimated potential risk for this receptor. To
better understand this uncertainty, RGs were developed based on risk to Carolina wren
with and without flying insects included in their diet (see Section 2.7.2.5 Ecological Risk
Assessment Summary).
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For aquatic avian receptors, the most significant potential exposure pathway was
determined to be ingestion of fish. The DDTR dataset for this pathway was from 2001,
which is historical and adds a notable level of uncertainty for receptors with diets
consisting of forage fish and predatory fish.
One of the three qualitatively evaluated endpoints (Assessment Endpoint 2: Protection
of Resident Fish Populations) showed risk with OU-2 fish tissue concentrations
exceeding risk-based fish tissue thresholds for mercury and DDTR, based on thresholds
developed by Beckvar, et al., 2005. Six receptors, representing four of the ten
assessment endpoints that were quantitatively assessed had LOAEL-based His that are
equal to or greater than the threshold value of 1. These endpoints are as follows:
• Assessment Endpoint 5: Carnivorous Aquatic Mammals - Receptor
Species: Mink
• Assessment Endpoint 6: Insectivorous Aquatic Birds - Receptor Species:
Pied-Billed Grebe
• Assessment Endpoint 7: Piscivorous Aquatic Birds - Receptor Species:
Belted Kingfisher, Little Blue Heron, and Great Blue Heron
• Assessment Endpoint 13: Insectivorous Terrestrial Birds - Receptor
Species: Carolina Wren
2.7.2.5 Ecological Risk Assessment Summary
Various biotic and abiotic field assessments were conducted for OU-2. These
assessments provide weight of evidence and information to estimate the potential risk to
biota in the assessment area. Because LOAEL-based His were equal to or exceeded
the threshold value of 1 for four of the ten assessment endpoints that were
quantitatively evaluated, and one of the three assessment endpoints that were
qualitatively evaluated (protection offish), potential risk must be concluded for these five
assessment endpoints.
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DDTR, HCB and mercury (inorganic and methylmercury) present a significant risk and
are referred to as the COCs in this ROD. Table 26 presents the ecological COCs and
their associated concentrations in each medium.
RGs for four of the five assessment endpoints were developed for mercury, HCB, and
DDTR in sediment and soil in the Remedial Goal Option Report (RGO)(AMEC, 2012a).
The RGO report did not develop RGs based on risk to fish from the same exposure
pathways. The EPA derived mercury and DDTR RGs for fish tissue; made changes to
the DDTR RG for insectivorous birds exposed to floodplain soils; made changes to the
DDTR RG for piscivorous birds feeding upon predatory fish; and modified the DDTR
RGs to include consideration of total organic carbon (TOC) concentrations (Appendix I
of this ROD).
RGs are intended to correspond to minimal and acceptable levels of effects on the
ecological assessment endpoints. In general, they correspond to small effects on
individual organisms that would be expected to cause minimal effects on populations
and communities. Though the risk assessment evaluated both total mercury and
methylmercury separately, RGs were established only for total mercury (inorganic +
methyl). Reducing total mercury and controlling the transformation processes that
produce methylmercury are the keys to reducing methylmercury concentrations in OU-
2. The RGs developed for fish tissue, soil and sediment are presented in Figures 24-30.
RGs for sediment were calculated using four methods:
• Biota-sediment Accumulation Factor (BSAF). RGs for mercury and DDTR
were calculated using the BSAF method. The BSAF method is typically
appropriate for lipophilic chemicals, and involves normalizing sediment
concentrations to organic carbon content, and normalizing biotic tissue to
organism lipid content. Mercury is not lipophilic, so normalizing to lipid content is
not necessary for mercury. However, in the OU-2 RGO document, the term
BSAF was defined more broadly, and the following process was conducted using
both normalized and non-normalized data to determine the best regression
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relationship. The BSAF method is a four-step process. Average fish tissue
concentrations (both normalized to lipid content and non-normalized) were first
graphed against average sediment concentrations (normalized to TOC and non-
normalized) based on the home ranges of various fish species. Site-specific
regression equations relating the tissue concentrations to sediment
concentrations were then developed using the graphs. The target fish tissue
concentration was then determined by back calculation of the aquatic risk
equations presented in the updated ERA. The target fish tissue concentration
was entered into the site-specific regression equation to obtain a corresponding
target sediment concentration (RG).
• The Ratio Method. RGs for mercury and DDTR were calculated by dividing the
average fish tissue concentration by the average sediment concentration. Home
ranges of the various fish species were not considered in the ratio method. This
approach is a simplified description of bioaccumulation and assumes mercury
and DDTR concentrations in fish increase without an upper bound as sediment
concentrations increase.
• Direct Calculation of RG. The RG for HCB was estimated by direct reduction of
sediment concentration in the forward risk calculation to achieve a hazard index
(HI) equivalent to 1. The BSAF approach was not required for HCB since risk
was driven by direct ingestion of abiotic media (i.e., sediment) and not through
ingestion of prey items that may bioaccumulate HCB through the food chain.
• Spreadsheet-based Ecological Risk Assessment for the Fate of Mercury
(SERAFM). SERAFM is a Microsoft® Excel model provided by the EPA that is
used to estimate target mercury sediment concentrations for aquatic ecological
receptors. SERAFM contains a mercury cycling module that models mercury
transformation processes (mercury <—> methylmercury) based on site-specific
conditions, and calculates RGs in terms of total mercury. SERAFM was used as
a line of evidence in the calculation of mercury RGs for sediment, along with the
BSAF and ratio BAF methods.
The sediment RG is the mercury concentration in sediment that will be protective
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of ecological receptors. The sediment remedial goals for mercury presented in
Figure 24 are based the BSAF approach. RG ranges based on SERAFM were
higher than those derived from the BSAF approach, with little overlap in the
ranges generated by the two different approaches for some receptors. A
comparison of the RG ranges developed from the two different approaches is
shown below.
Receptor
RG Range -
RG Range -
BSAF Approach
SERAFM
(mg/kg)
Approach (mg/kg)
Belted Kingfisher - Forage Fish
0-2.3
i
C\|
Diet
Belted Kingfisher - Mixed Diet
4.4-20
14.8-17.6
Little Blue Heron
1.2-9
10.7-13.6
Great Blue Heron
1 -12
13.1 -16.0
Mink
27
30.6-32.7
Pied-billed Grebe
14-109
33.9-35.9
RGs forfloodplain soils were calculated using the following methods:
• Soil-to-invertebrate Bioaccumulation Factor (BAF). Invertebrate tissue
concentrations were graphed against average floodplain soil concentrations (0-
to 6- inch-depth interval), and site-specific regression equations relating the
tissue concentrations to surface soil concentrations were developed. The target
invertebrate tissue concentration was then determined by back calculation of the
terrestrial risk equations presented in the updated ERA, with one modification:
the EPA substituted a TRV for terrestrial birds that was not based on an eggshell
thinning endpoint. This change was made because, as reported elsewhere, egg-
shell thinning does not appear to be an important mechanism for reproductive
impairment in terrestrial birds (Beaver, 1980; Gill, et. al, 1993). For derivation of
the floodplain soil RG, the EPA selected a NOAEL TRV of 1.04 mg/kg-d and a
LOAEL TRV of 1.3 mg/kg-d from data presented in the EPA Eco SSL for DDT
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(USEPA, 2007). The LOAEL TRV represents the first bounded reproduction
study with a LOAEL less than 4.66 (the geometric mean of all NOAELs for DDT)
that did not have an eggshell endpoint (Table 5-1 of USEPA, 2007). For the
NOAEL TRV, the EPA selected the highest NOAEL less than 1.3 mg/kg-d that
was not an eggshell study. The target invertebrate tissue concentration was
entered into the site-specific regression equation to obtain a corresponding target
surface soil RG.
• The Ratio Method. RGs for mercury and DDTR were calculated by dividing the
average invertebrate tissue concentration by the average floodplain soil
concentration. Home ranges of the various invertebrate species were not
considered in the ratio method. This approach is a simplified description of
bioaccumulation and assumes mercury and DDTR concentrations in
invertebrates increase without an upper bound as soil concentrations increase.
RGs for fish tissues were calculated using the following methods:
• Wildlife Dose Modeling. Fish RGs based on protection of wildlife receptors
were based on the same BSAF relationships used to derive the wildlife RGs. Fish
RGs for protection of wildlife represent the fish tissue concentration that results in
a dose equal to the TRV. Equations representing the BSAFs for fish from
sediment were presented in the RGO report.
• Selection of Tissue Effects Levels. Fish RGs based on protection of fish
themselves represent toxicological thresholds selected from the literature. The
fish RG for mercury represents the 10th percentile lower effects level from
Beckvar, et. al (2005), and the fish RG for DDTR represents the tissue threshold
effects level (t-TEL) from Beckvar et. al (2005).
Table 28 presents the RGs for ecological receptors.
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2.8 REMEDIAL ACTION OBJECTIVES
The primary COC at OU-2 is mercury, which best represents the extent of
contamination in sediments and biota in the Basin and Round Pond. The other COCs
include HCB and DDTR. The primary release mechanism for mercury and HCB to OU-2
was the discharge through the former wastewater ditch. The presence of DDTR is a
result of indirect discharges from the Ciba-Geigy Superfund site located immediately
north of OU-2. Olin did not manufacture DDT or intermediate daughter products
associated with DDTR at its Mcintosh plant.
Remedial action objectives (RAOs) are established to support the evaluation of
remedial alternatives for areas with the potential for unacceptable risk as identified in
the human health and ecological risk assessments. The RAOs are established by
specifying contaminants and media of concern, potential exposure pathways, and
remediation goals.
• Reduce, or mitigate, risk to piscivorous birds from ingestion of fish
exposed to mercury contaminated sediments. The mercury RG
recommended for sediments range from 1.6 to 10.7 mg/kg. The lower end of the
recommended range represents the RG for protection of little blue heron based
on the BSAF model approach, while the upper end of the range represents risk to
little blue heron based on the SERAFM model.
• Reduce or mitigate, risk to piscivorous mammals from incidental ingestion
of HCB contaminated sediments. The HCB RG for OU-2 sediments is 7.6
mg/kg. The HCB RG is recommended for protection of piscivorous mammals.
• Reduce, or mitigate, risk to piscivorous birds from ingestion of fish
exposed to DDTR contaminated sediments.
The recommended DDTR RG range for OU-2 sediments is 0.32 - 0.91 mg/kg to
be protective of piscivorous birds.
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• Reduce risk to humans from ingestion of fish.
The recommended RG of 0.3 mg/kg for mercury in fish fillets is based on the fish
tissue based water quality criterion.
• Reduce fish tissue concentrations of mercury to levels protective of fish
and piscivorous wildlife
The EPA selected a mercury RG range of 0.20 - 0.28 mg/kg in whole body
forage fish (e.g. mosquitofish) to be protective offish and piscivorous wildlife.
The EPA selected a mercury RG range of 0.28 - 0.43 mg/kg in whole body
predatory fish (e.g., largemouth bass) to be protective offish and piscivorous
wildlife.
• Reduce fish tissue concentrations of DDTR to levels protective of fish and
piscivorous wildlife.
The EPA selected a DDTR RG range of 0.23 - 0.52 mg/kg in whole body forage
fish (e.g. mosquitofish) to be protective offish and piscivorous wildlife. The EPA
selected a DDTR RG 0.64 mg/kg in whole body predatory fish (e.g., largemouth
bass) to be protective offish. The recommended sediment DDTR RG for
protection offish is 0.21 mg/kg.
• Reduce, or mitigate, risk to ecological receptors exposed to COCs in
contaminated floodplain soils.
The recommended mercury RG range for OU-2 soils is 0.54 - 1.9 mg/kg to be
protective of insectivorous birds. The recommended DDTR RG range for OU-2
soils is 0.18 -1.12 mg/kg to be protective of insectivorous birds.
• Restore surface water to meet water quality standards.
The water quality criteria for mercury, DDTR, and HCB in impaired waters of
Alabama is 0.012 /yg/L; 0.0001 /yg/L; and 0.0002 /yg/L, respectively. The criterion
will be applied in the Basin to ensure that mercury, DDTR, and HCB are not
leaving the Site at levels of concern.
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2.9 DESCRIPTION OF ALTERNATIVES
Under its legal authorities, the EPA's primary responsibility at Superfund sites is to
undertake remedial actions that are protective of human health and the environment. In
addition, Section 121 of CERCLA establishes several other statutory requirements and
preferences, including: a requirement that the EPA's remedial action, when complete,
must comply with all federal and more stringent state environmental and facility siting
standards, requirements, criteria or limitations, unless a waiver is invoked; a
requirement that the EPA select a remedial action that is cost-effective and that utilizes
permanent solutions and alternative treatment technologies or resource recovery
technologies to the maximum extent practicable; and a preference for remedies in which
treatment permanently and significantly reduces the volume, toxicity or mobility of the
hazardous substances is a principal element over remedies not involving such
treatment. Remedial alternatives were developed to be consistent with these
Congressional mandates. Treatment of contaminated sediments at OU-2 is not practical
because of the high volume of contaminants anticipated and the low concentration of
mercury. Therefore, treatment alternatives for sediment were not generated. The
remedial action alternatives for the Olin OU2 Site are as follows:
1. No Action
2A. In situ capping, institutional controls (ICs) and engineering controls (ECs)
2B. In situ capping, dry capping, ICs and ECs
2C. Dry capping, ICs and ECs
3. Debris removal, hydraulic dredging, dewatering, onsite or offsite disposal,
ICs and ECs
2.9.1 Alternative 1: No Action
The No Action alternative provides a baseline for comparison with the range of other
developed alternatives. Its inclusion among the alternatives is mandated by the EPA
guidance. The No Action alternative assumes that the berm and gate structure would
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not be maintained and that current restrictions on trespassing and fishing would not be
enforced.
2.9.2 Alternative 2A: In Situ Capping, Institutional Controls (ICs) and Engineering
Controls (ECs)
Alternative 2A combines in situ capping, ICs and ECs. In this alternative, a cap would
be applied over the areas of sediment exceeding the RGs. Figure 30 shows the area
where mercury concentrations are above and below the RGs for surficial sediment and
includes the channel connecting the Basin and Round Pond. The footprint for DDTR
and HCB falls within the mercury remedial footprint. The sorption characteristics
associated with HCB and DDTR are such that a cap effective at containing mercury will
also be effective at containing DDTR and HCB. The remedial footprint for capping is
approximately 72.5 acres based on the 1.6 mg/kg mercury contour. The remedial
footprint for capping mercury encompasses sediments above the HCB and DDTR
PRGs. Figures 31 and 32 show the HCB and DDTR contours along with the mercury
remedial footprint for capping. Surficial sediment would be sampled again during the
design phase and prior to cap placement to confirm the remedial footprint. This cap
would serve as a barrier between the environment and the COCs in the sediment, thus
reducing risks to acceptable levels. A cap typically consists of 3 layers: 1) a mixing zone
layer, 2) a cap material layer, and 3) a habitat layer. The mixing or transition zone layer
would consist of native soil and would be placed immediately above the sediment
surface. It allows for mixing between the sediment and the cap material during
placement. The cap material layer is placed above the mixing zone and should not mix
into the contaminated sediment. A thin layer of reactive cap material such as, but not
limited to, pelletized activated carbon, apatite, or biopolymers, may also be applied to
further sequester and isolate the COCs. The uppermost layer is the habitat layer, and, if
needed, with armor (stone placement to prevent erosion). The habitat layer provides a
depth of material that allows burrowing organisms to re-colonize the habitat without
breaching the cap material layer. A model for the migration of mercury was performed,
and preliminary results indicate that an appropriate cap would be effective in meeting
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cleanup levels. Biogenic gases may be generated underneath a cap and may be
released episodically. Cap design typically includes active or passive venting
mechanisms to prevent gas ebullition from disturbing the cap. Slopes amenable to
capping without special measures must be less than or equal to 2:1 (horizontal to
vertical). Review of the slopes in the deeper portion of the Basin indicates that the
slopes are 2:1 or less. Implementation would take approximately 1 year. Water levels
would be managed through the berm and gate system through the completion of
construction to maintain a consistent water level for equipment mobility and limit the
influence of potential floods.
ICs and ECs would be employed to limit risks to human receptors. ICs would consist of
modifying the existing OU-1 deed and use restrictions to include OU-2; ECs would
consist of warning signs, some of which are already present at OU-2, fencing, and
continuation of security measures. OU-2 is currently fenced along the west, north, and
southwest boundary.
This alternative would need to comply with the substantive requirements of the Clean
Water Act (CWA) and Alabama NPDES requirements and with Floodplain Management,
Protection of Wetlands, the ADEM Coastal Area Management Program, and Alabama
Water Pollution Control regulations.
2.9.3 Alternative 2B: In situ Capping, Dry Capping, ICs and ECs
Alternative 2B combines in situ capping, dry capping, ICs and ECs. In this alternative,
the portion of the Basin that is at elevation -5 feet NAVD88 (approximately 22 acres) or
lower would be capped in situ, as in Alternative 2A. The portions of the Basin that are
shallower than -5 feet NAVD88 (approximately 43 acres) and Round Pond
(approximately 8 acres) would be capped in the dry. This area would be incrementally
segregated with cofferdams into 300- by 400-foot sections and dewatered. The water
would be pumped from this small, segregated portion of the Basin to above-ground
modular settling tanks, located on the bluff. Solids would settle inside the modular
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settling tank, and the water would be returned to the remaining portion of the Basin. A
geotextile would be placed in the dewatered parcel, and then a cap would be applied by
earth moving equipment. This cap would provide a barrier between the environment and
the COCs in the sediment, thus reducing risks to acceptable levels. The cap would be
as described in Alternative 2A (including the mixing zone, cap material layer, and
habitat layer), but would be a total thickness of approximately 24 inches to provide a
stable surface for equipment. Work would begin in shallower areas of the Basin (south
and southeast) and move towards the deeper portion of the Basin in an incremental
fashion, moving the cofferdams as each parcel is capped. Water levels would be
managed through the berm and gate system through the completion of construction to
maintain the dewatered sections or to provide appropriate water levels for equipment
access. Water-level management would also limit the influence of potential floods
during remedial action. ICs would consist of modifying the OU-1 deed and use
restrictions to include OU-2; ECs would consist of signs, some of which are already
present at OU-2, fencing, and continuation of security measures. OU-2 is currently
fenced along the west, north, and southwest boundary. Implementation would take
approximately 7 months.
2.9.4 Alternative 2C: Dry Capping, ICs and ECs
In this alternative, Alternative 2C combines dry capping, ICs and ECs. Areas of Basin
and Round Pond that exceed the remediation goal as specified in Alternative 2A would
be capped in the dry as described in Alternative 2B. In this alternative, 300- by 400-foot
sections of the Basin and Round Pond would be isolated with cofferdams and
dewatered. The water would be pumped to above-ground storage tanks, located on the
bluff. Solids would settle inside the storage tanks, and the water would be returned to
the Basin. A geotextile would be placed in the dewatered parcel, and then a cap would
be applied over the areas of the sediment exceeding the remediation goal, as shown in
Figure 33.
This cap would provide a barrier between the environment and the COCs in the
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sediment, thus reducing risks to acceptable levels. The cap would be as described in
Alternative 2A but would be a total thickness of about 24 inches to provide a stable
surface for equipment. Work would begin from the bluff and proceed towards the east
side of the Basin in an incremental fashion, moving the portadams as each section is
capped. Implementation would take approximately 7 months. Water levels would be
managed using the berm and gate system through the completion of construction to
maintain the dewatered section. ICs, including deed and use restrictions, and ECs,
including signs, fencing, and security monitoring, would be employed to limit risks to
human receptors.
2.9.5 Alternative 3: Debris Removal, Dredging, Dewatering, Onsite or Offsite
Disposal, ICs and ECs
Alternative 3 combines mechanical debris removal, hydraulic dredging, dewatering,
onsite or offsite disposal, ICs and ECs. The extensive buried debris identified in the
debris survey would be removed using a mechanical rake. Debris, consisting of mostly
large logs and stumps, is buried within the sediment and covers over 40 to 50 percent of
the southern portion of the Basin and 30 percent of the northern portion of the Basin.
Buried debris is present over approximately 15 percent of the area in the deeper central
portion of the Basin. The estimate for the central portion of the Basin may be low
because fine materials in the sediment may absorb the seismic energy used in the
survey so that buried features are not detected. Hydraulic dredging would follow debris
removal.
The approximate footprints for dredging from 0 to 4 feet in depth are shown in 1 -foot
increments on Figures 30-33 and are based on an RG of 1.6 to 10.7 mg/kg mercury in
sediment. The isoconcentration contours drawn on Figure 35 are based on the 2009
surficial sediment results, including both fine core and grab sample results. Figures 36-
38 show isoconcentration contours based on the 2009 coarse core results for sediment.
Mercury concentrations exceeding 1.6 to 10.7 mg/kg at depths greater than 4 feet are
present in the deeper portion of the Basin. This deeper portion of the Basin is delineated
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by the pink line on Figure 35. Mercury concentrations in sediment greater than 4 feet in
depth are listed on Figures 36 through 38. Mercury isoconcentration contours were not
drawn for depths greater than 4 feet, because mercury sample locations with
concentrations exceeding 1.6 to 10.7 mg/kg are limited to one to three locations,
depending on depth. Most of the Basin would be dredged to 4 feet in depth. The area
shown on Figure 35 encompassing the deeper portion of the Basin and reaching to the
area of the former discharge ditch would be dredged to an average depth of 6 feet. The
center of the deeper portion could be dredged up to a depth of 13 feet. Round Pond
would be dredged to a depth of 1 foot. The area in the Basin to be dredged to 4 feet is
approximately 43 acres; the area within the deeper portion of the Basin to be dredged is
approximately 21 acres; and the area in Round Pond to be dredged to 1 foot is
approximately 8 acres. Additional sediment sampling is recommended in the remedial
design phase to confirm the area and volume for the remedial footprint before
implementing the remedial action. The remedial footprint includes the channel
connecting Round Pond to the Basin and the perimeter of floodplain soils that are often
inundated. The volume of in-place sediment to be removed in this alternative is
approximately 590,000 cubic yards (cy).
Hydraulic dredging would mix water into the sediments to yield a dredged material
consisting of approximately 10 percent solids. The average in place percent solids is
approximately 40 percent. Reducing the solids content from 40 percent to 10 percent
would consume more than the 2.9 times the volume of water available in the Basin at
the 6-foot water elevation. Water from the Tombigbee River would need to be directed
into the Basin during dredging to provide sufficient water for dredging. The dredged
material would then be dewatered either mechanically or in Geotubes®. The volume of
dredged material to be dewatered in this alternative would be approximately 2,390,000
cy. It is assumed that the dredged material would then be dewatered to approximately
60 percent solids. It is assumed the dewatered solids would be disposed of as non-
hazardous material. This assumption would be verified through TCLP analysis.
Dewatering fluid would then be treated to meet AWQC and discharged to the Basin.
Treatment would primarily consist of an equalization tank and a minimum of two
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activated carbon units.
Silt curtains would be used to limit the migration of suspended sediment. Water levels
would be managed through the berm and gate system during dredging to maintain a
consistent water level for equipment mobility. The remedial action would take
approximately 17 months. Transport of suspended sediment would increase during the
flooding season. OU-1 ICs would need to be modified to consist of deed and use
restrictions; ECs would consist of signs, some of which are already present at OU-2,
fencing, and continuation of security measures. OU-2 is currently fenced along the west,
north, and southwest boundary.
2.10 DETAILED ANALYSIS OF ALTERNATIVES
2.10.1 Alternative 1: No Action
Estimated Capital Costs: $ 0
Estimated 0 & M Costs: $ 0
Estimated Present Worth: $ 0
Estimated Construction Time: Not Applicable
Estimated Time to Achieve Cleanup Levels and RAOs: Would Not Achieve
2.10.1.1 Overall Protection of Human Health and the Environment
The No Action alternative provides a baseline for comparison with the range of other
developed alternatives. Its inclusion among the alternatives is mandated by the EPA
guidance. The No Action alternative assumes that the berm and gate structure would
not be maintained and that Olin's current security monitoring and restrictions on
trespassing and fishing would not be enforced so that risk to human receptors would
increase above acceptable levels. Risk to ecological receptors through bioaccumulation
would not be mitigated. Under this alternative the timeframe to achieve the sediment
cleanup levels in the Basin and Round Pond would be very lengthy and beyond the
timeframe evaluated in this FS.
The No Action alternative is not considered protective of human health or the
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environment.
2.10.1.2 Compliance with ARARs
The No Action alternative does not comply with ARARs.
2.10.1.3 Long-Term Effectiveness
The No Action alternative is not considered effective in the long term.
2.10.1.4 Short-Term Effectiveness
The No Action alternative is not considered effective in the short term.
2.10.1.5 Reduction of TMV through Treatment
This alternative does not include any measures to reduce TMV.
2.10.1.6 Implementability
No measures are implemented under this alternative.
2.10.1.7 Cost
The No Action Alternative has no capital or maintenance cost.
2.10.1.8 State/Support Agency Acceptance
During implementation of the Rl, FS, and BLRA, the EPA has worked under a
Cooperative Management Agreement with the State of Alabama (represented by
ADEM). ADEM has concurred on the Rl, FS, and BLRA, the underlying studies upon
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which selection of the remedial action is based. ADEM has expressed concerns
regarding the proposed DDTR cleanup level. The response to their comments are
included in the Responsiveness Summary to this ROD.
2.10.1.9 Community Acceptance
During the public comment period for the proposed plan, only two entities submitted
written comments. In general, all comments supported the preferred alternative
presented in the Proposed Plan, although there were comments regarding the DDTR
cleanup levels. The responses to these comments are included in the Responsiveness
Summary to this ROD.
2.10.2 Alternative 2A- In Situ Capping, ICS, and ECS
Estimated Capital Costs: $ 12,400,000 - $21,500,000
Estimated O & M Costs: $ 993,000
Estimated Present Worth: $ 12,900,000 - $22,000,0000
Estimated Construction Time: 12 months
Estimated Time to Achieve Cleanup Levels and RAOs: 10 years
2.10.2.1 Overall Protection of Human Health and the Environment
An in situ cap serves as a barrier separating other media and potential ecological
receptors from exposure to COCs in the sediment, thereby reducing risk. Risk to
piscivorous birds stems from ingestion offish exposed to mercury or DDTR in
sediments. A cap would prevent fish exposure to the COCs in sediments and diffusion
into surface water. Fish tissue mercury and DDTR concentrations would meet the EPA
fish tissue concentration remediation goals once the current generations offish have
naturally expired. Risk to piscivorous mammals stems from incidental ingestion of HCB-
contaminated sediments. A cap would provide a barrier between the piscivorous
mammals and the contaminated sediments, eliminating their exposure pathway. ICs
and ECs currently in place have already achieved the RAO to reduce or mitigate the
current potential risk to humans from ingestion offish. This alternative includes the
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current potential risk to humans from ingestion offish. This alternative includes the
continuation of these ICs and ECs.
2.10.2.2 Compliance with ARARs
This alternative would comply with ARARs. A cap would prevent exposure of fish to
COCs in sediment, and fish tissue mercury concentrations would reduce over time to
the risk-based fish tissue residue criterion for mercury of 0.3 mg/kg. A cap would cover
the sediments, meeting the RGs for mercury, DDTR, and HCB in sediment. Workers
would wear appropriate personal protective equipment (PPE) for the protection of
worker safety. Discharges to waters of the State would comply with the substantive
requirements of the Clean Water Act (CWA) and Alabama NPDES requirements.
Engineering controls would be employed to prevent the disruption of, impact to, or
alteration of wetlands during remedial action, thereby complying with Floodplain
Management, Protection of Wetlands, the ADEM Coastal Area Management Program,
and Alabama Water Pollution Control ARARs.
2.10.2.3 Long-Term Effectiveness
An in situ cap would be effective in the long term at achieving RAOs. Sediment caps
have been approved by the EPA for remediation at many sites. The footprint of the cap
would encompass approximately 72.5 acres based on the 1.6 mg/kg mercury contour
and would cover the areas where sediment RGs are exceeded so that the exposure
pathway is eliminated. The cap will be constructed to effectively create the exposure
barrier.
A cap is typically applied in multiple lifts to minimize resuspension of sediment and
mixing. Allowing the sediment and cap materials a zone for mixing ensures that mixing
will not extend into the cap material layer. The potential for suspended particles that
contain mercury to become entrained in the water column will be reduced through the
layered application of the mixing zone and cap material. Amendments and polishing
agents such as pelletized activated carbon, apatite, hematite, organoclay, pelletized
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Selection of cap material, potential amendments, and/or a polishing layer will be
evaluated during the remedial design. Cap design typically includes venting
mechanisms to prevent gas ebullition from disturbing the cap. The effectiveness of
various cap materials can be evaluated and compared using models that predict the
migration of mercury through the cap materials.
The Steady-State Cap Design Model (Lampert and Reible, 2008 or equivalent) will be
used during remedial design phase after performing a treatability study to predict the
performance and longevity of the cap materials to contain mercury based on prior
agreement with the EPA.
All input test parameters including Kd values of cap materials would be calculated from
site-specific treatability studies during the design phase. Other input parameters that are
impractical to simulate in a laboratory setting will be estimated based on conservative
calculations/challenged conditions. For example, calculation of the Darcy velocity
assumes that a groundwater pathway between the bluff and Basin exists. Core logs
show that clay indicative of a hydraulic conductivity of 10~5 to 10~11 centimeters per
second (cm/s) underlies the Basin/Round Pond throughout and provides an effective
barrier between the Basin and groundwater. Groundwater flow from the bluff is
expected to travel under the Basin through the more permeable sand aquifer beneath
the Basin or parallel to the Basin to discharge south of the Basin to the Tombigbee
River. A pathway under or parallel to the Basin is the pathway of least resistance,
resulting in little, if any, groundwater upwelling through the clay and into a cap.
Extremely conservative assumptions will be used to calculate a Darcy velocity or
groundwater upwelling to this input to the model. Darcy velocity or groundwater
upwelling is a function of hydraulic conductivity and the hydraulic gradient within the cap
layer. The hydraulic gradient between the bluff area and the Basin/Round Pond will be
used as a very conservative value. The hydraulic gradient was estimated using the
water level elevation in monitoring well MW-1B along the bluff and 3 feet NAVD88. An
elevation of 3 feet presents a worst case or higher gradient when water levels in the
Basin are near drought conditions and a minimum water elevation is not maintained in
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the Basin. A minimum water elevation of 6 feet is currently maintained in the Basin. The
hydraulic conductivity near the surface of the sediment core is estimated at 10~5 cm/s,
while the hydraulic conductivity near the bottom of the deeper cores is estimated at 10"11
cm/s. Using a value greater than 10"11 cm/s for hydraulic conductivity is extremely
conservative, because groundwater flow or upwelling would be controlled by the lower
of the hydraulic conductivity values. The range of inputs using the effective hydraulic
conductivity, hydraulic gradient, and effective porosity results in an equivalent seepage
velocity range of 0.96 to 96 cm/year.
The preliminary model, performed during the feasibility study, showed that migration of
mercury through typical cap materials can effectively protect human health and the
environment. The actual cap thickness and composition would be determined during the
remedial design phase of the remedial action.
HCB and DDTR
Cap material attenuating mercury should be capable to attenuate both HCB and DDTR
due to their hydrophobicity and low solubility in water. The water solubility of mercuric
chloride is several orders of magnitude higher than that of HCB (0.0062 mg/L; USEPA,
1996) and DDT (4,4' DDT of 5.5 |jg/L to 2,4' of |jg/L 85 ug/L). These chemical
properties indicate that an effective cap for mercury would also be effective for HCB and
DDTR. The actual cap thickness and composition would be determined during the
remedial design phase.
2.10.2.4 Short-Term Effectiveness
RAOs would be achieved with the completion of the cap placement and natural
replacement of the current generation of fish. A period of 10 years is common for higher
trophic fish such as largemouth bass and less for lower trophic fish. Unacceptable risk
to the community is not anticipated during remedial activities. Engineering controls such
as appropriate PPE would be employed to mitigate short-term risks during construction.
Short-term impacts to the Basin/Round Pond habitat are expected with the capping
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alternative. Placement of cap materials could bury benthic organisms, which could
impact feeding of upper trophic level animals, such as some fish and bird species.
Placement of cap materials may also bury large, woody debris, thus limiting habitat,
cover, and food for aquatic species. These impacts are expected to be temporary.
Benthic organisms would recolonize the habitat layer of the cap. A temporary increase
in turbidity associated with the fine material in the cap material is expected during cap
placement, but this turbidity increase would not be excessive and would be controlled
through the application rate and placement method of the cap. The short-term adverse
effects of capping would be temporary and manageable.
2.10.2.5 Reduction of TMV Through Treatment
In situ capping would reduce the mobility of contaminated sediment by creating a barrier
over the contamination and preventing exposure. The habitat would provide a clean
layer of material for benthic organisms to populate without breaching the integrity of the
cap material layer from the top of the cap. The mixing zone at the bottom of the cap,
immediately above the sediment, would provide a zone for sediment and cap mixing,
preventing the sediment from breaching the integrity of the cap layer from the bottom of
the cap.
Capping with an appropriate material that contains active ingredients provides
sequestration of contaminants (a treatment) by design and installing the cap so that it
achieves the following risk reduction objectives in accordance with the Contaminated
Sediment Guidance for Hazardous Waste Site (USEPA, 2005).
• "Physical isolation of the contaminated sediment sufficient to reduce exposure
due to direct contact and to reduce the ability of burrowing organisms to move
contaminants to the surface"
• "Stabilization of contaminated sediment and erosion protection of sediment and
cap, sufficient to reduce resuspension and transport to other sites"
• "Chemical isolation of contaminated sediment sufficient to reduce exposure
from dissolved and colloidally bound contaminants transported into the water
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column"
Mobility and toxicity to biota would be reduced as a result of this treatment. Treatment
residuals are not a concern for this alternative. Capping is considered permanent with
appropriate armor for protection against erosion/resuspension and proper maintenance.
2.10.2.6 Implementability
ICs would need to be modified to include OU-2 and ECs are already implemented. The
capping placement technologies under consideration in this alternative are generally
available and sufficiently demonstrated for use at OU-2. The necessary equipment and
specialists are also available. Silt curtains would be employed to isolate a capped area
from a non-capped area so that potential resuspension in a working area would not
affect a completed capped area.
A debris survey of the Basin indicated that large buried debris (tens of meters long by
several meters wide) is present in 30 to 50 percent of the Basin and protrudes 10s of
centimeters from the sediment bed. An advantage of a cap is that it does not require
debris removal; the cap can be applied over and around the debris, avoiding the
significant resuspension caused by the removal of buried debris.
Uncertainties identified with this alternative include:
• Road conditions: Roads and/or bridges in and around OU-2 would need
improvement to handle the movement of cap materials from the onsite borrow
area or the delivery of offsite materials.
• Land availability: Parcels of land near OU-2 would need to be developed as
construction equipment and material staging areas. The bluff area could be
used to stage and store materials.
• Construction: Implementation would be approximately 1 year from initiation of
mobilization to completion of demobilization. Application of the cap would take
approximately six of the twelve total months.
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approximately six of the twelve total months.
Future remedial actions are not anticipated once the cap is placed. Compliance with
permits would be required. Monitoring would consist of sampling to monitor COC
concentrations in sediment and fish tissue over time.
2.10.2.7 Cost
The cost for Alternative 2A is presented in the table below. The actual composition and
thickness of the cap would be specified during the remedial design. Costs for Alternative
2A include the following:
• Remedy design, treatability studies, and project/construction management
• Mobilization and setup of decontamination facilities
• Labor, equipment, and materials for 12 months of operations
• Site preparation, including building of access roads, and the reinforcement of
existing bridges and roads
• Cap slurry system for mixing and pumping of cap material into the Basin and
Round Pond
• Erosion controls such as silt fences and silt curtains
• Pre-construction bathymetric survey and ongoing surveys during application
• Cap materials - four types of typical cap materials were included in the cost
estimates, representing the range of potential costs
• Site restoration such as re-grading the borrow area of the bluff prior to
demobilization
• Demobilization
• Post construction confirmation sampling of sediment and surface water.
• Long-term operations, maintenance, monitoring, and reporting including:
o Annual berm inspections and maintenance
o 30 years of long term monitoring at the following schedule:
• Topographic survey of cap 4 years after remedy completion
and every five years thereafter
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completion and every 5 years thereafter
• Surface water monitored for low-level mercury quarterly for
the first year and annually thereafter
• Largemouth bass monitored for mercury 18 months after
remedy completion and annually until year 5, then every 5
years, coinciding with the year before the 5-Year Review
Report (5YRR)
• Forage fish tissue monitored for mercury and DDTR 12
months after remedy completion and annually until year 5,
then every 5 years, coinciding with the year prior to 5YRR
• Spiders and flying insects monitored for mercury and DDTR
12 months after remedy completion and annually until year
5, then every 5 years, coinciding with the year prior to 5YRR
o Monitoring Reports and 5-Year Review Reports
The projected costs are tabulated below.
Alternative 2A
Total Cost
(Capital + O&M)
Total Present Worth
Native Soil Cap
Bentonite Pellet Cap
Native Cap/Polishing Soil Layer
Bentonite Pellet Cap/Polishing Layer
$13,400,000
$16,900,000
$18,900,000
$22,500,000
$12,900,000
$16,400,000
$18,400,000
$22,000,000
The estimated present worth cost is based on the capital costs incurred during the first
year and operation, maintenance, and monitoring (OM&M) for 30 years. It is expected
that remedial goals would be met within 10 years, based on the life cycle of the higher
trophic fish species. The costs incurred beyond the 30 years was negligible for this
project. An annual discount rate of 7 percent was applied to calculate present worth.
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2.10.2.8 State/Support Agency Acceptance
During implementation of the Rl, FS, and BLRA, the EPA has worked under a
Cooperative Management Agreement with the State of Alabama (represented by
ADEM). ADEM has concurred on the Rl, FS, and BLRA, the underlying studies upon
which selection of the remedial action is based. ADEM has expressed concerns
regarding the proposed DDTR cleanup level. The response to their comments are
included in the Responsiveness Summary to this ROD.
2.10.2.9 Community Acceptance
During the public comment period for the proposed plan, only two entities submitted
written comments. In general, all comments supported the preferred alternative
presented in the Proposed Plan, although there were comments regarding the DDTR
cleanup levels. The responses to these comments are included in the Responsiveness
Summary to this ROD.
2.10.3 Alternative 2B - In Situ Capping, Dry Cappings, ICS and ECS
Estimated Capital Costs: $ 13,300,000 - $22,400,000
Estimated O & M Costs: $ 981,000
Estimated Present Worth: $ 13,800,000 - $22,900,000
Estimated Construction Time: 7 months
Estimated Time to Achieve Cleanup Levels and RAOs: 10 years
2.10.3.1 Overall Protection of Human Health and the Environment
Overall protection of human health and the environment for Alternative 2B is consistent
with Alternative 2A.
2.10.3.2 Compliance with ARARs
Compliance with ARARs for the in situ capping portion of Alternative 2B is consistent
with Alternative 2A. The dry capping portion of Alternative 2B would also comply with
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ARARs. A cap placed in the dry would comply with chemical-specific ARARs by
preventing exposure offish to COCs in sediment, thereby reducing fish tissue mercury
concentrations over time to the risk-based fish tissue residue criterion for mercury of 0.3
mg/kg. A cap would cover the sediments, meeting the PRGs for mercury, DDTR, and
HCB in sediment. Workers would wear appropriate PPE for the protection of worker
safety. Dry capping activities would be completed in compliance with the action specific
general construction standards for land disturbing activities such as implementation of
best management practices (BMPs). Discharges to Waters of the State would comply
with the substantive requirements of the Clean Water Act (CWA) and Alabama NPDES
requirements. Engineering controls would be employed to prevent the disruption of,
impact to, or alteration of wetlands during remedial action, thereby complying with the
location-specific ARARs for Floodplain Management, Protection of Wetlands, the ADEM
Coastal Area Management Program, and Alabama Water Pollution Control. USFWS
would be consulted prior to implementation of this alternative, in compliance with the
location-specific ARAR for drainage of water bodies.
2.10.3.3 Long-Term Effectiveness
Long-term effectiveness for Alternative 2B is consistent with Alternative 2A.
2.10.3.4 Short-Term Effectiveness
Short-term effectiveness for Alternative 2B is consistent with Alternative 2A, with some
exceptions. Short-term impacts to the Basin/Round Pond habitat are expected to be
higher in the portion that is capped in the dry compared to that which is capped in situ.
Dry capping involves segregating the Basin/Round Pond, dewatering one section at a
time, and placing a geotextile and covering with native soils. Dewatering and covering
areas of the Basin/Round Pond would temporarily destroy the benthic habitat, which
could impact feeding of upper trophic level animals, such as some fish and bird species.
Aquatic and semi-aquatic species would be impacted because of the lack of water in
some areas of the Basin. Placement of cap materials may also bury large woody debris,
limiting habitat, cover, and food for aquatic species once water is returned to the
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previously dry areas. These impacts are expected to be temporary, but may last several
years. Benthic organisms will recolonize the habitat layer of the cap. Unlike dredging,
which is associated with substantially increased risks, as discussed later, the short-term
adverse effects of capping are temporary and manageable.
2.10.3.5 Reduction of TMV Through Treatment
Reduction of TMV through treatment for Alternative 2B is consistent with 2A. Capping
with amendments provides a treatment element by designing the cap so that it achieves
the following risk reduction objectives in accordance with the Contaminated Sediment
Guidance for Hazardous Waste Site (USEPA, 2005).
• "Physical isolation of the contaminated sediment sufficient to reduce exposure
due to direct contact and to reduce the ability of burrowing organisms to move
contaminants to the surface"
• "Stabilization of contaminated sediment and erosion protection of sediment and
cap, sufficient to reduce resuspension and transport to other sites"
• "Chemical isolation of contaminated sediment sufficient to reduce exposure from
dissolved and colloidal-bound contaminants transported into the water column"
Mobility and toxicity to biota would be reduced as a result of this treatment.
Treatment residuals are not a concern for this alternative. Capping is
considered permanent with appropriate armor for protection against
erosion/resuspension and proper maintenance.
2.10.3.6 Implementability
The ICs for OU-1 will need to be modified to include OU-2 and ECs are already
implemented. The technologies for in situ capping and for using portadams to segregate
the Basin/Round Pond, dewatering sections of the Basin/Round Pond, and placing the
cap in this alternative are generally available. The necessary equipment and specialists
are available. Additional materials, such as geotextiles and an increased cap thickness,
would also be required to create a stable working surface. Debris, within the sediment
bed to be capped in the dry, would be removed after dewatering and prior to the
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placement of the geotextile. This debris is assumed to be nonhazardous and would be
transported to an offsite landfill for disposal. Uncertainties identified with this alternative
include:
• Road conditions: Roads and/or bridges in and around OU-2 would need
improvement to handle the movement of cap materials from the onsite borrow
area or the delivery of offsite materials.
• Land availability: Parcels of land near OU-2 would need to be developed as
construction equipment and material staging areas. The bluff area could be
used to stage and store materials.
• Timeframe: Implementation is estimated to be of shorter duration than in situ
capping alone (approximately 7 months from initiation of mobilization to
completion of demobilization). Actual time spent on placing the cap accounts
for about 4 out of the 7 months (2 months for dry portion and 2 months for in
situ portion). However, flooding greater than 11 feet NAVD88 would shut down
the dry capping operation and disrupt operations. This would lead to a greater
amount of downtime during the dry capping portion of operations.
Future remedial actions are not anticipated once the cap is placed. Compliance with
permits would be required. Monitoring would consist of sediment sampling to monitor
COC concentrations in sediment and fish tissue over time.
2.10.3.7 Cost
The cost for Alternative 2B is presented in the table below. Costs for Alternative 2B
include the following:
• Remedy design, treatability studies, and project/construction management
• Mobilization and setup of decontamination facilities
• Labor, equipment, and materials for 7 months of operations
• Site preparation, including building of access roads, and the reinforcement of
existing bridges and roads
• Erosion controls such as silt fences and silt curtains
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• Pre-construction bathymetric survey and ongoing surveys during application
• For the in situ capping portion (23 acres):
o Cap slurry system for mixing and pumping of native soil cap material into the
Basin and Round Pond
• For the dry capping portion (49.5 acres):
o Installation of portadams in Basin to segregate and dewater
o Dewatering of Basin segments and Modutanks
o Excavation and transport of borrow area soil from bluff to Basin
• Total thickness of native soil cap equal to 24 inches to provide a firm base for
equipment mobility: cap design consists of a 2 inch native soil mixing zone, 18
inches of native soil cap material layer, and a 4 inch habitat layer consisting
native soil with armor. Gas venting mechanisms would be included in the cap
placement.
• Site restoration such as regrading the borrow area of the bluff prior to
demobilization
• Demobilization
• Site restoration such as regrading the borrow area after excavation
• Long-term operations, maintenance, monitoring, and reporting, including:
o Berm and cap maintenance
o 30 years of long term monitoring at the following schedule:
¦ Topographic survey of cap 4 years after remedy completion and every five
years thereafter
¦ Sediment cores monitored for mercury 4 years after remedy completion
and every 5 years thereafter
¦ Surface water monitored for low-level mercury quarterly for the first year
and annually thereafter
¦ Predatory fish tissue monitored for mercury 18 months after remedy
completion and annually until year 5, then every 5 years, coinciding with
the year before the 5-Year Review Report (5YRR)
¦ Forage fish tissue monitored for mercury and DDTR 12 months after
remedy completion and annually until year 5, then every 5 years,
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coinciding with the year prior to 5YRR
¦ Spiders and flying insects monitored for mercury and DDTR 12 months
after remedy completion and annually until year 5, then every 5 years,
coinciding with the year prior to 5YRR
¦ Monitoring Reports and 5-Year Review Reports
A native soil cap composition for Alternative 2B was used for costing to provide a basis
of comparison to the OU-2 native soil cap in Alternative 2A. Costs for adding cap
amendments or polishing layers would be similar to the costs for these materials
provided in Alternative 2A. The projected costs are tabulated below.
Alternative 2B
In Situ Capping and Dry Capping
Total Cost (Capital + O&M)
$14,300,000-$24,400,000
Total Present Worth
$13,800,000-$22,900,000
The estimated present worth cost is based on the capital costs incurred during the first
year and operation, maintenance, and monitoring (OM&M) for 30 years. It is expected
that remedial goals would be met within 30 years, based on the life cycle of the higher
trophic fish species (approximately 10 years). Costs incurred beyond the 30 years were
negligible for this project. An annual discount rate of 7 percent was applied to calculate
present worth.
2.10.3.8 State/Support Agency Acceptance
During implementation of the Rl, FS, and BLRA, the EPA has worked under a
Cooperative Management Agreement with the State of Alabama (represented by
ADEM). ADEM has concurred on the Rl, FS, and BLRA, the underlying studies upon
which selection of the remedial action is based. ADEM has expressed concerns
regarding the proposed DDTR cleanup level. The response to their comments are
included in the Responsiveness Summary to this ROD.
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2.10.3.9 Community Acceptance
During the public comment period for the proposed plan, only two entities submitted
written comments. In general, all comments supported the preferred alternative
presented in the Proposed Plan, although there were comments regarding the DDTR
cleanup levels. The responses to these comments are included in the Responsiveness
Summary to this ROD.
2.10.4 Alternative 2C- Dry Cappings, ICS, and ECS
Estimated Capital Costs: $ 15,400,000 - $24,500,000
Estimated O & M Costs: $ 981,000
Estimated Present Worth: $ 15,900,000 - $25,000,000
Estimated Construction Time: 7 months
Estimated Time to Achieve Cleanup Levels and RAOs: 10 years
2.10.4.1 Overall Protection of Human Health and the Environment
Overall protection of human health and the environment for Alternative 2C is consistent
with Alternatives 2A and 2B.
2.10.4.2 Compliance with ARARs
Compliance with ARARs for Alternative 2C is consistent with Alternative 2A and 2B.
2.10.4.3 Long-Term Effectiveness
Long-term effectiveness for Alternative 2C is consistent with Alternatives 2A and 2B.
2.10.4.4 Short-Term Effectiveness
Short-term effectiveness for Alternative 2C is consistent with Alternative 2B. Short-term
impacts to the Basin/Round Pond habitat are expected to be higher with the dry capping
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alternative compared to in situ capping. The dry capping alternative involves
segregating the Basin/Round Pond, dewatering one section at a time, and placing a
geotextile and covering with native soils. Dewatering and covering areas of the
Basin/Round Pond would temporarily destroy the benthic habitat, which could impact
feeding of upper trophic level animals, such as some fish and bird species. Aquatic and
semi-aquatic species would be impacted because of the lack of water in some areas of
the Basin. Placement of cap materials may also bury large woody debris, limiting
habitat, cover, and food for aquatic species once water is returned to the previously dry
areas. These impacts are expected to be temporary, but may last several years. Benthic
organisms will recolonize the habitat layer of the cap. Unlike dredging, which is
associated with substantially increased risks, as discussed later, the short-term adverse
effects of capping are temporary and manageable.
2.10.4.5 Reduction of TMV Through Treatment
Reduction of TMV through treatment for Alternative 2C is consistent with Alternatives
2A and 2B. Capping with or without amendments provides a treatment element by
designing the cap so that it achieves the following risk reduction objectives in
accordance with the Contaminated Sediment Guidance for Hazardous Waste Site
(USEPA, 2005).
• "Physical isolation of the contaminated sediment sufficient to reduce exposure
due to direct contact and to reduce the ability of burrowing organisms to move
contaminants to the surface"
• "Stabilization of contaminated sediment and erosion protection of sediment and
cap, sufficient to reduce resuspension and transport to other sites"
• "Chemical isolation of contaminated sediment sufficient to reduce exposure
from dissolved and colloidal-bound contaminants transported into the water
column"
Mobility and toxicity to biota would be reduced as a result of this treatment. Treatment
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residuals are not a concern for this alternative. Capping is considered permanent with
appropriate armor for protection against erosion/resuspension and proper maintenance.
2.10.4.6 Implementability
ICs and ECs are already implemented. The technologies for using portadams to
segregate the Basin/Round Pond, dewatering sections of the Basin/Round Pond, and
placing the cap in this alternative are generally available. The necessary equipment and
specialists are available. Additional materials, such as geotextiles and an increased cap
thickness, would also be required to create a stable working surface.
Uncertainties identified with this alternative include:
• Road conditions: Roads and/or bridges in and around OU-2 would need
improvement to handle the movement of cap materials from the onsite borrow
area or the delivery of offsite materials.
• Land availability: Parcels of land near OU-2 would need to be developed as
construction equipment and material staging areas. The bluff area could be
used to stage and store materials.
• Timeframe: Implementation is estimated to be of shorter duration than in situ
capping (approximately 7 months from initiation of mobilization to completion of
demobilization). It is estimated that 4 out of the 7 months would be spent on
placing the cap. However, flooding greater than 11 feet NAVD88 would shut
down the dry capping operation and disrupt operations. This would lead to a
greater amount of downtime.
Future remedial actions are not anticipated once the cap is placed. Compliance with
permits would be required. Monitoring would consist of sediment sampling to monitor
COC concentrations in sediment and fish tissue over time.
2.10.4.7 Cost
The cost for Alternative 2C is presented in the table below. Costs for Alternative 2C
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include the following:
• Remedy design, treatability studies, and project/construction management
• Mobilization and setup of decontamination facilities
• Labor, equipment, and materials for 7 months of operations
• Site preparation, including building of access roads, and the reinforcement of
existing bridges and roads
• Erosion controls such as silt fences and silt curtains
• Pre-construction bathymetric survey and ongoing surveys during application
• Installation of portadams in Basin to segregate and dewater
• Dewatering of Basin segments and Modutanks
• Excavation and transport of borrow area soil from bluff to Basin
• Total thickness of native soil cap equal to 24 inches: cap design consists of a 2
inch native soil mixing zone, 18 inches of native soil cap material layer, and a 4
inch habitat layer consisting native soil with armor, Site restoration such as
regrading the borrow area of the bluff prior to demobilization
• Demobilization
• Long-term operations, maintenance, monitoring, and reporting, including:
o Berm and cap maintenance
o 30 years of long term monitoring at the following schedule:
¦ Topographic survey of cap 4 years after remedy completion and
every five years thereafter
¦ Sediment cores monitored for mercury 4 years after remedy
completion and every 5 years thereafter
¦ Surface water monitored for low-level mercury quarterly for the
first year and annually thereafter
¦ Predatory fish tissue monitored for mercury 18 months after
remedy completion and annually until year 5, then every 5
years, coinciding with the year before the 5-Year Review Report
(5YRR)
¦ Forage fish tissue monitored for mercury and DDTR 12 months
after remedy completion and annually until year 5, then every 5
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years, coinciding with the year prior to 5YRR
¦ Spiders and flying insects monitored for mercury and DDTR 12
months after remedy completion and annually until year 5, then
every 5 years, coinciding with the year prior to 5YRR
o Monitoring Reports and 5-Year Review Reports
A native soil cap composition for Alternative 2C was used for costing to provide a basis
of comparison to the site native soil cap in Alternative 2A. Costs for adding cap
amendments as polishing layers would be similar to the costs for these materials
provided in Alternative 2A. The projected costs are tabulated below.
Alternative 2C
Dry Capping with Native Soil
Total Cost (Capital + O&M)
$16,400,000 -$25,000,000
Total Present Worth
$15,900,000 -$25,000,000
The estimated present worth cost is based on the capital costs incurred during the first
year and operation, maintenance, and monitoring (OM&M) for 30 years. It is expected
that remedial goals would be met within 30 years, based on the life cycle of the higher
trophic fish species (approximately 10 years). Costs incurred beyond the 30 years are
negligible for this project. An annual discount rate of 7 percent was applied to calculate
present worth.
2.10.4.8 State/Support Agency Acceptance
During implementation of the Rl, FS, and BLRA, the EPA has worked under a
Cooperative Management Agreement with the State of Alabama (represented by
ADEM). ADEM has concurred on the Rl, FS, and BLRA, the underlying studies upon
which selection of the remedial action is based. ADEM has expressed concerns
regarding the proposed DDTR cleanup level. The response to their comments are
included in the Responsiveness Summary to this ROD.
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2.10.4.9 Community Acceptance
During the public comment period for the proposed plan, only two entities submitted
written comments. In general, all comments supported the preferred alternative
presented in the Proposed Plan, although there were comments regarding the DDTR
cleanup levels. The responses to these comments are included in the Responsiveness
Summary to this ROD.
2.10.5 Alternative 3- Debris Removal, Hydraulic Dredging, Dewatering, Onsite or
Offsite Disposal, ICS, and ECS
Estimated Capital Costs: $ 54,400,000 - $69,000,000
Estimated O & M Costs: $ 784,000
Estimated Present Worth: $ 54,800,000 - $69,400,0000
Estimated Construction Time: 17 months
Estimated Time to Achieve Cleanup Levels and RAOs: 10 years
2.10.5.1 Overall Protection of Human Health and the Environment
Dredging would provide for mass removal of COCs but may or may not be successful in
removing sediments without significant COC residuals remaining. Risk to ecological
receptors may or may not be reduced to acceptable levels as a result of resuspension
during dredging and post-dredging residuals. Dredging would resuspend sediment,
release contamination, and generate residuals. Resuspension and residuals remaining
in the sediment would likely be up to 5% depending on characteristics of sediment,
despite efforts to reduce residuals using hydraulic dredging methodologies, because of
the extensive mechanical debris removal required. Dredging would limit other media
and potential ecological receptors from exposure to COCs, thereby reducing risk. Risk
to piscivorous birds stems from ingestion offish exposed to mercury- or DDTR-
contaminated sediments. Sediment removal may prevent fish exposure to the
contaminated sediments and diffusion into surface water. Fish tissue mercury and
DDTR concentrations may meet the EPA-recommended fish tissue concentration
consumption guideline once the current generations offish have naturally expired. Risk
to piscivorous mammals stems from incidental ingestion of HCB-contaminated
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sediments. Sediment removal would reduce their exposure to the COCs. ICs and ECs
currently in place have already achieved the RAO to reduce or mitigate the current
potential risk to humans from ingestion offish. This alternative includes the continuation
of these ICs and ECs.
2.10.5.2 Compliance with ARARs
This alternative would comply with ARARs if risk reduction standards are met. Sediment
removal would theoretically prevent fish from exposure to contaminated sediment above
3 to 6 mg/kg, and fish tissue mercury concentrations may reduce over time to the risk-
based fish tissue residue criterion of 0.3 mg/kg. Discharges to waters of the State would
comply with the substantive requirements of the CWA and Alabama Water Quality
Standards and NPDES requirements. Engineering controls would be employed to
prevent the disruption of, impact to, or alteration of wetlands during remedial action,
thereby complying with Floodplain Management, Protection of Wetlands, the ADEM
Coastal Area Management Program, and Alabama Water Pollution Control ARARs.
2.10.5.3 Long-Term Effectiveness
While dredging is considered effective in mass removal, it is often unsuccessful in
reducing surficial sediment concentrations and reducing risk to acceptable levels
because resuspension of sediment generates a residual layer of contamination that is
left behind. It is difficult to estimate the amount of contamination that may be released or
the amount of residual contamination that will remain after dredging. Releases of
contaminants into surface water may be up to about 5 percent of the contaminant mass,
even when proper precautions and equipment are used to reduce resuspension. Low
sediment bulk density and the presence of debris tend to increase resuspension and
residuals. Extensive buried debris is present in the Basin as discussed above.
Resuspension and post dredge residuals could prevent achievement of RAOs.
Monitoring after implementation of this alternative would consist of fish tissue and
sediment sampling to evaluate the reduction of mercury concentrations. Long-term
maintenance and management would consist of maintaining the ICs and ECs.
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2.10.5.4 Short-Term Effectiveness
RAOs may or may not be achieved depending on resuspension and post-dredge
residuals. The timeframe to reach RAOs would be approximately 10 years for higher
level trophic fish such as largemouth bass. Unacceptable risk to the community is not
anticipated during remedial activities. Engineering controls such as appropriate PPE
would be employed to mitigate short-term risks to workers during construction.
2.10.5.5 Reduction of TMV Through Treatment
Dredging reduces the volume of contamination by removing mass. Reducing the solids
content from 40 percent to 10 percent during hydraulic dredging would consume more
than 2.9 times the volume of water available in the Basin at the 6-foot water elevation.
Water from the Tombigbee River would need to be directed into the Basin during
dredging to provide sufficient water for dredging. Mixing water from the Tombigbee
River directly with sediment containing COCs above the PRGs during the dredging
process would increase the volume of material requiring dewatering, handling, and
discharge. This alternative is considered permanent.
2.10.5.6 Implementability
OU-1 ICs would need to be modified to include OU-2 and ECs are already
implemented. The dredging technologies under consideration in this alternative are
generally available and sufficiently demonstrated for use at OU-2. The necessary
equipment and specialists are also available. Silt curtains would be employed to isolate
areas actively being dredged from those previously dredged so that potential
resuspension in a working area would limit effects on a completed area.
A debris survey of the Basin indicated that large buried debris (tens of meters long by
several meters wide) is present over 30 to 50 percent of the shallow area of the Basin.
Buried debris is a significant disadvantage to dredging alternatives. Presence of debris
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is a contributing factor to increased resuspension and residual volume, which can
prevent the achievement of RAOs.
This alternative would require the disposal of dewatered solids from dredging either
onsite or offsite. Dredged material is assumed to be non-hazardous for disposal. This
assumption would be verified through TCLP analysis. Adequate landfill capacity is
available for the disposal of the dredged material. Offsite disposal would require the
transport of materials to the EPA-approved and permitted facility. Sufficient land for
onsite disposal is available along the bluff, as depicted in Figure 34.
Uncertainties identified with this alternative include:
• Road conditions: Roads and/or bridges in and around OU-2 would need
improvement to handle the movement of construction materials and process
equipment.
• Land availability: Parcels of land near OU-2 would need to be developed as
construction equipment and material staging areas and potentially for
Geotube® dewatering areas. The bluff area could be used to stage and store
materials and eventually be used as an onsite landfill area.
• Timeframe: Implementation would be approximately 17 months with
approximately 12 of the 17 months spent on sediment dredging. Flooding
greater than 11 feet NAVD88 would disrupt operations and potentially increase
duration.
Future remedial actions are not anticipated once dredging is complete. ICs and ECs
would be maintained in the long term. Compliance with the substantial requirements of
the permits would be required. Monitoring would consist of sampling to evaluate COC
concentrations in sediment and fish tissue with time.
2.10.5.7 Cost
The costs for Alternative 3 with onsite and offsite disposal of the dredged sediments are
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presented in the tables below. Either all of the dewatered sediment would be disposed
of onsite or offsite. A combination of onsite and offsite disposal is not anticipated.
Costs for Alternative 3 include the following:
• Remedy design, treatability studies, and project/construction management
• Mobilization and setup of decontamination facilities
• Labor, equipment, and materials for 17 months of operations
• Site preparation, including building of access roads, and the reinforcement of
existing bridges and roads
• Installation of land-based filter press dewatering system and pipeline to pump
dredged material from barge to filter press
• Erosion controls such as silt fences and silt curtains
• Pre-construction bathymetric survey and ongoing surveys during dredging
• Mechanical debris removal and hydraulic dredging
• Dewatering of dredged material through a mechanical filter press
• Treatment of decanted water using settling tanks and activated carbon units
and discharge to Basin or NPDES discharge
• Transportation and disposal of debris in an offsite non-hazardous landfill
• Onsite disposal:
o Construction of a disposal cell in the borrow area to be lined with an high
density polyethylene (HDPE) liner and 2-feet of clay,
o Transportation of dredged material to the onsite disposal cell
o 2-foot clay cover over the dredged material
o Re-grading and seeding the landfill area
• For offsite disposal:
o Transportation and disposal of dredged material in an offsite non-hazardous
landfill
• Demobilization
• Long-term operations, maintenance, monitoring, and reporting including:
o Berm and landfill cell maintenance
o Confirmation sampling performed upon completion of dredging and 1 year
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later
o 30 years of long term monitoring at the following schedule:
¦ Surface water monitored for low-level mercury quarterly for the first
year and annually thereafter
¦ Predatory fish tissue monitored for mercury 18 months after remedy
completion and annually until year 5, then every 5 years, coinciding
with the year before the 5-Year Review Report (5YRR)
¦ Forage fish tissue monitored for mercury and DDTR 12 months after
remedy completion and annually until year 5, then every 5 years,
coinciding with the year prior to 5YRR
¦ Spiders and flying insects monitored for mercury and DDTR 12
months after remedy completion and annually until year 5, then every 5
years, coinciding with the year prior to 5YRR
o Monitoring Reports and 5-Year Review Reports
The projected costs are tabulated below.
Alternative 3
Dredging with Onsite
Disposal
Dredging with Offsite
Disposal
Total Cost (Capital + O&M)
$55,200,000
$69,800,000
Total Present Worth
$54,800,000
$69,400,000
The estimated present worth cost is based on the capital costs incurred during the first
year and OM&M for 30 years. It is expected that remedial goals would be met within 30
years, based on the life cycle of the higher trophic fish species (approximately 10
years). Costs incurred beyond the 30 years tend to be negligible for this project. An
annual discount rate of 7 percent was applied to calculate present worth.
2.10.5.8 State/Support Agency Acceptance
During implementation of the Rl, FS, and BLRA, the EPA has worked under a
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Cooperative Management Agreement with the State of Alabama (represented by
ADEM). ADEM has concurred on the Rl, FS, and BLRA, the underlying studies upon
which selection of the remedial action is based. ADEM has expressed concerns
regarding the proposed DDTR cleanup level. The response to their comments are
included in the Responsiveness Summary to this ROD.
2.10.5.9 Community Acceptance
During the public comment period for the proposed plan, only two entities submitted
written comments. In general, all comments supported the preferred alternative
presented in the Proposed Plan, although there were comments regarding the DDTR
cleanup levels. The responses to these comments are included in the Responsiveness
Summary to this ROD.
2.11 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The EPA uses nine NCP criteria to evaluate remedial alternatives for the cleanup of a
release. These nine criteria are categorized into three groups: threshold, balancing, and
modifying. The threshold criteria must be met in order for an alternative to be eligible for
selection. The threshold criteria are overall protection of human health and the environment
and compliance with Applicable or Relevant and Appropriate Requirements (ARARs). The
balancing criteria are used to weight major tradeoffs among alternatives. The five balancing
criteria are long-term effectiveness and permanence; reduction of toxicity, mobility or
volume through treatment; short-term effectiveness; implementability; and cost. The
modifying criteria are state acceptance and community acceptance.
2.11.1 Overall Protection of Human Health and the Environment
No Action, Alternative 1, would result in unacceptable risk to human health and the
environment through lack of maintenance of the current ICs and ECs. Alternative 1
would not reduce COC concentrations in sediment to remedial goals. The capping
alternatives 2A, 2B, and 2C, isolate COCs in sediment from contact with other media
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and receptors and are protective of human health and the environment. Alternative 3,
which involves dredging, carries a risk of residual COCs, particularly for mercury, and
resuspension that could prevent the achievement of RAOs and temporarily increase
COC concentrations in surface water and biota. Alternative 3 may not be protective of
human health and the environment. There is more certainty that capping mercury
contaminated sediments at OU-2 will be protective of human health and the
environment as compared to dredging mercury contaminated sediments at OU-2.
2.11.2 Compliance with ARARs
Section 121(d) of CERCLA and the NCP §300.430(f)(l)(ii)(B) require that
remedial actions at CERCLA sites at least attain legally applicable or relevant and
appropriate Federal and more stringent State requirements, standards, criteria, and
limitations which are collectively referred to as "ARARs," unless such ARARs are
waived under CERCLA §121 (d)(4). Compliance with ARARs addresses whether a
remedial alternative will meet all of the applicable or relevant and appropriate
requirements of other Federal and more stringent State environmental
statutes/regulations or provides a basis for invoking a waiver. See 40 C.F.R. §
300.430(e)(9)(iii)(B).
Applicable requirements, as defined in 40 C.F.R. § 300.5, means those cleanup
standards, standards of control, and other substantive requirements, criteria, or
limitations promulgated under federal environmental or state environmental or facility
siting laws that specifically address a hazardous substance, pollutant, or contaminant,
remedial action, location, or other circumstance at a CERCLA site. Relevant and
appropriate requirements, as defined in 40 C.F.R. § 300.5, means those cleanup
standards, standards of control, and other substantive requirements, criteria, or
limitations promulgated under federal environmental or state environmental or facility
siting laws that, while not "applicable" to a hazardous substance, pollutant, or
contaminant, remedial action, location, or other circumstance at a CERCLA site,
address problems or situations sufficiently similar to those encountered at a CERCLA
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site that their use is well suited to the particular site. Only those state standards that are
identified by the state in a timely manner and that are more stringent than federal
requirements may be applicable or relevant and appropriate. See 40 C.F.R. §
300.400(g)(4).
For purposes of ease of identification, the EPA has created three categories of ARARs:
Chemical-, Location- and Action-specific. Under 40 C.F.R. § 300.400(g)(5), the lead and
support agencies shall identify their specific ARARs for a particular site and notify each
other in a timely manner as described in 40 C.F.R. § 300.515(d). Chemical-, and
Location-specific ARARs should be identified as early as scoping phase of the
Remedial Investigation, while Action-specific ARARs are identified as part of the
Feasibility Study for each remedial alternative. See 40 C.F.R. §§ 300.430(b)(9) &
300.430(d)(3). In addition, per 40 CFR 300.405(g)(3), other advisories, criteria, or
guidance may be considered in determining remedies (known as To Be Considered or
TBC). The TBC category typically consists of advisories, criteria, or guidance that were
developed by the EPA, other federal agencies, or states that may be useful in
developing CERCLA remedies.
In accordance with 40 CFR §300.400(g), the EPA and the State of Alabama have
identified site-specific ARARs and TBC for the remedial alternatives including the
selected remedy. The Chemical-specific, Action-specific, and Location-specific ARARs
and TBC for the each of the remedial alternatives were included in Table 2-1, Table 2-2,
and Table 2-3 of the Olin OU-2 Feasibility Study.
Capping Alternatives 2A, 2B, and 2C comply with ARARs. The dredging Alternative 3
may or may not comply with ARARs depending upon the amount of resuspension and
residuals remaining after dredging. There is concern that mercury remaining in dredge
residuals and resuspended sediment in Alternative 3 will result in noncompliance with
ARARs based on the estimated amount of residuals and resuspension up to 5%.
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2.11.3 Long-Term Effectiveness
Alternative 3 may not be effective in the long term based on the amount of resuspension
and residuals associated with debris removal and dredging. Modeling using site-specific
data has predicted that capping, Alternatives 2A, 2B, and 2C, would be effective in the
long term. The EPA has approved caps for remediation at many sites.
2.11.4 Short-Term Effectiveness
Alternative 3 is not considered effective in the short term. In addition, severe, adverse,
short-term impacts, such as increases of mercury concentrations in fish tissue and
surface water are expected to occur with the dredging Alternative 3.
The capping Alternatives 2A, 2B, and 2C would effectively isolate the contaminated
sediment in the short term. Short-term impacts from capping would be temporary and
reversible.
2.11.5 Reduction of TMV through Treatment
Capping Alternatives 2A, 2B, and 2C with amendments would provide an element of
treatment to reduce mobility and toxicity (bioavailability) through physical isolation,
stabilization, and chemical isolation of the COCs in sediment under the cap. The
dredging Alternative, 3, would reduce volume through mass removal, but would
temporarily increase COC mobility through release and resuspension. The dredging
alternative would also increase the volume of contaminated sediment by increasing the
water content through hydraulic dredging.
2.11.6 Implementability
ICs and ECs are already implemented at OU-2. Alternative 2A, capping, is
implementable with well-proven technologies and equipment. Uncertainties are
associated with Alternatives 2B and 2C, which involve dry capping, such as the ability to
segregate and dewater the Basin/Round Pond and the ability to create a stable working
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surface. Additional time, materials, and labor would be required for Alternatives 2B and
2C. Alternative 3, dredging, is implementable with proven technologies and equipment.
2.11.7 Cost
Alternatives 2A, 2B, and 2C have similar costs and are within the range of $12,900,000
- $25,000,000 depending upon what amendments are added to the cap. Alternative 3
has a cost range of $54,800,00 - $69,400,000. The cost difference is significant
between the capping alternatives and the dredging alternative.
2.11.8 State/Support Agency Acceptance
During implementation of the Rl, FS, and BLRA, the EPA has worked under a
Cooperative Management Agreement with the State of Alabama (represented by
ADEM). ADEM has concurred on the Rl, FS, and BLRA, the underlying studies upon
which selection of the remedial action is based and the preferred alternative. ADEM has
expressed concerns regarding the proposed DDTR cleanup level. The response to their
comments are included in the Responsiveness Summary to this ROD.
2.11.9 Community Acceptance
During the public comment period for the proposed plan, only two entities submitted
written comments. In general, all comments supported the preferred alternative
presented in the Proposed Plan, although there were comments regarding the DDTR
cleanup levels. The responses to these comments are included in the Responsiveness
Summary to this ROD.
2.11.10 Summary
Five alternatives for remediation of sediments at OU-2 were compared in the previous
section. Dredging (Alternative 3) can be expected to result in mobilization and
redistribution of mercury as well as potential increases in fish tissue and surface water
mercury concentrations. Dredging may also not be effective in the long term based on
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the amount of resuspension and residual concentrations associated with dredging and
debris removal. Dredging is also a more costly alternative. There is more certainty that
in situ or dry capping or a combination of the two (Alternatives 2A, 2B, and 2C), will be
protective of human health and the environment, will comply with ARARs, and would
effectively isolate the sediment from exposure to humans and the environment.
Preliminary model results, based on current information and assumptions discussed in
this FS, predicted that capping would be effective in the long term. While the costs of in
situ capping (Alternative 2A) are comparable to dry capping (Alternative 2C) or a
combination of the two (Alternative 2B), there is less uncertainty with the
implementation of Alternative 2A. Uncertainties associated with Alternatives 2B and 2C
include disruption due to flooding. The specific cap composition and thickness will be
refined as part of the remedial design. The preliminary conclusion of the model that a
cap will be effective will be verified by treatability studies during the design phase.
2.12 PRINCIPAL THREAT WASTE
Waste classified as a principal threat is a "source material considered to be highly toxic
or highly mobile that generally cannot be reliably contained or would present a
significant risk to human health or the environment should exposure occur". Source
material is defined by the EPA as "material that includes or contains hazardous
substances, pollutants, or contaminants that act as a reservoir for migration of
contamination to groundwater, to surface water, to air, or acts a source for direct
exposure." The EPA expects to use "treatment to address the principal threats posed
by a site, wherever practicable" and "engineering controls, such as containment, for
waste that poses a relatively low long-term threat" as stated in the NCP.
Low level threat wastes generally can be reliably contained and present only a low risk
in the event of a release. They typically exhibit low toxicity, low mobility, or are near
health-based levels. The inherent toxicity, the physical state, the potential mobility, and
the degradation products of the material are all taken into account. Although there is not
a "bright-line" threshold, if the toxicity and mobility of the source material combine to
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pose a potential risk of 10-3 or greater, the EPA generally expects that treatment
alternatives (i.e. soil vapor extraction, biodegradation, in-situ oxidation, stabilization,
grouting, etc.) should be evaluated. For example, surface or subsurface soils that
contain high concentrations of contaminants of concern that are potentially mobile due
to volatilization, surface runoff, or sub-surface transport, would generally be considered
principal threat wastes. Similarly, highly toxic or bioaccumulative wastes that have the
potential to pose an immediate threat to human health or the environment, or which may
accumulate through the food chain, such as soil or waste materials containing mercury,
may be considered principal threat wastes.
Conversely, surface soil that contains contaminants of concern that are relatively
immobile in air or groundwater (i.e. non-liquid, low volatility, low leachability) would be
more likely categorized as low level threat waste and not necessarily require treatment.
The EPA provided further guidance on principal threat waste in a 1997 "rules of thumb"
document (USEPA, 1997). In addition to the concepts above, guidance states that the
reasonably anticipated future land use at a site should be taken into account when
determining whether wastes pose a principal threat. "When the baseline risks
associated with the reasonably anticipated future land use trigger action, the definition
of principal threat wastes may be determined by the reasonably anticipated future land
use scenario as well. A general rule of thumb is to consider as a principal threat those
source materials with toxicity and mobility characteristics that combine to pose a
potential risk several orders of magnitude greater than the risk level that is acceptable
for the current or reasonably anticipated future land use, given realistic exposure
scenarios."
The COCs at Olin OU-2 are mercury, DDTR, and HCB. The following sections address
these COCs as they relate to toxicity, mobility, and containment at Olin OU-2.
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2.12.1 Human Health and Ecological Risk Summary
A HHRA was performed to evaluate the total risk from the COCs based on migration
pathway, exposure routes, exposure concentrations, receptors, and geochemical and
ecological factors. It was determined that carcinogenic risk from DDTR and HCB did not
exceed the 1.0E-3 level discussed in the 1991 USEPA Guidance. The current
carcinogenic risk to humans ranges from 2.0E-06 to 7.0E-06 and is within the EPA
generally acceptable range. Potential future risk rises only to 3.0E-05 even if access is
unrestricted by Olin, which is below the 1.0E-03 threshold that may be considered in
making a principal threat waste determination. The non-carcinogenic risk from mercury
is due to ingestion of mercury in fish tissue, not due to direct contact with sediment or
water. Under a future use scenario, the non-carcinogenic risk to an adult consumer of
fish is an estimated HI of 6. DDTR and HCB were negligible contributors to non-
carcinogenic risk with maximum HQs of 0.2, and accounted for less than 5% of the total
HI values in all scenarios. While the EPA has not verified an acute-based toxicity value
for methylmercury, ATSDR does have a recommended Minimal Risk Level (MRL) of
0.0007 mg/kg-d for acute oral exposure to mercuric chloride (inorganic mercury). Since
this value is 70 times the chronic RfD/MRL used in the Olin HHRA for methyl mercury,
no health effects would be expected from an acute exposure to the dose calculated in
the HHRA.
Using conservative methods of calculating risk, ecological risk associated with OU-2 is
also low, with a maximum low-effects based HI of 10 for belted kingfisher modeled with
a maximum dose scenario. Low-effects HI values ranged from 0.63 to 10, dependent
upon receptor. Ingestion of mercury in fish tissue accounted for 70% of the HI for belted
kingfisher, with ingestion of DDTR in fish tissue accounting for the remaining 30% of the
HI. For little blue heron, the next most sensitive receptor, consumption of mercury and
DDTR in prey items each accounted for roughly 50% of the HI. These HI values are
based on potential chronic effects, and though an HI in excess of 1 is indicative of
chronic risk, an HI less of 10 does not likely indicate the potential for acute risk. As with
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human health risk, ecological risk was driven largely by ingestion of COCs in the food-
chain and not due to direct contact with COCs in sediment or water.
The source material is at the bottom of the Basin and Round Pond, 76 and 4 acres,
respectively. Water depths range up to 40 feet in the Basin. The area is inundated by
floodwaters from the Tombigbee River between fall and the end of spring each year.
The consolidated sediment bed in the Basin and Round Pond are stable throughout
various hydrodynamic events, such as wind-driven currents, or river flows during floods
and it is highly unlikely that sediments below 6 inches would ever be mobilized or
scoured. Therefore, a reasonable anticipated exposure to the submerged sediments is
within the top 6 inches of consolidated bed sediment and suspended sediment.
2.12.2 Toxicity
Mercury is generally considered a toxic substance with the degree of toxicity dependent
upon the form of mercury and concentration. Mercury was historically discharged to the
Basin in the form of mercuric salts, not as elemental mercury. Mercury likely exists in
the sediment and surface water as mercury (2+) and to a lesser degree as methylated
mercury. Methylmercury comprised approximately 0.00736 to 0.136 percent of the total
mercury species based on 2009 data, The maximum methylmercury percentage
observed in all data collected from 2008 to 2010 was 0.29%, which was observed
during the drought year of 2008.
DDTR and HCB concentrations in the sediment and floodplains soils do not pose an
acute risk to human health or ecological receptors as documented in the human health
risk assessment and ecological risk assessment. The HHRA determined that the
quantitative risk from DDTR and HCB is orders of magnitude below the 10-3 level
discussed in the 1991 USEPA Guidance for carcinogens, as shown below. Mercury is
not considered a carcinogen and thus is not included in the carcinogenic risk evaluation.
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Receptor Population
Carcinogenic Risk
(Total Risk Across All
Media)
Resident Trespasser, Adult (Current)
6 x 10"6
Resident Trespasser, Adult (Future)
3 x 10"5
Resident Trespasser, Pre-Adolescent/Adolescent (Current)
2 x 10"6
Resident Trespasser, Pre-Adolescent/Adolescent (Future)
7 x 10"6
The NCP discusses principal threat waste as having high concentrations of toxic
compounds. The preamble of the NCP defines high concentrations of toxic compounds
as "several orders of magnitude above levels that allow for unrestricted use and
unlimited access." The principal threat waste fact sheet (USEPA, 1991) further refines
these "levels" to mean risk-based levels. For OU-2, the mercury risk-based remedial
goals generally fall within the range of 3 to 6 mg/kg total mercury in sediment. Two
orders of magnitude greater than this clean-up range would be 300 to 600 mg/kg. Since
1991, 502 surface sediment samples, defined here as any sample within the top 6
inches of sediment, have been collected in OU-2. Since 1991, different depth intervals
(e.g. 0 to 4 inches, 0 to 6 inches) have been designated as surface sediment samples.
For purposes of this discussion, anything with the top 6 inches is defined here as
"surface sediment" because this represents the most likely exposure horizon and
bioturbation zone for ecological receptors in OU-2. Seven of the 502 surface sediment
samples (1.4%) exceeded 300 mg/kg, and one sample (0.2%) exceeded 600 mg/kg, as
listed below.
178 subsurface samples, defined as any depth interval below the top 6 inches of
sediment, have been collected in OU-2, with three samples (1.7%) exceeding 300
mg/kg and no samples exceeding 600 mg/kg. Two of the three subsurface samples that
exceeded 300 mg/kg were collected in 2009 in the deeper portion of the Basin
(Locations SDCR-5 and SDCR-8), and occurred at sediment depths of 3 to 4 feet and 5
to 6 feet below sediment surface, respectively. The third subsurface sample that
exceeded 300 mg/kg was not collected in the Basin, but was collected in the outfall
ditch that carried runoff from the manufacturing facility. This sample was collected at a
depth of 4 to 5 feet below the sediment surface.
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Number of Samples Exceeding 300 mg/kg and 600 mg/kg for Mercury
Year
Total Number
# of Samples
# of Samples
Range of
of Samples
Exceeding
Exceeding
Concentrations
300 mg/kg
600 mg/kg
(mg/kg)
Surface Sediment
2006-2010
247
0
0
1 -220
2001
76
5
0
3.4 - 590
1994-1995
31
1
1
0.07-780
1991 -1992
148
1
0
0.13-329
Subsurface Sediment
2009
110
2
0
0.02-440
2001
30
0
0
0.4-270
1995
6
0
0
0.35-161
1991-1992
32
1
0
0.19-329
Another interpretation of the NCP and fact sheet referenced above is that the exposure
point concentration may be used to equate a COC concentration to a risk level. The 95
percent upper confidence limit (UCL) for mercury in sediment was used in the ecological
and human health risk assessments as the exposure point concentration. The data
collected amongst years, locations, and depths were combined to form 24 different
exposure concentration scenarios. The 95 percent UCLs for mercury in sediment
ranged from 20.5 to 70.7 mg/kg across the 24 scenarios. These values are less than the
"several orders of magnitude" specified in the NCP (USEPA, 1990). In this scenario,
high concentrations of toxic compounds are defined as those associated with risk above
10-3 and 95% UCLs. OU-2 sediment does not contain high concentrations of toxic
compounds under this definition.
2.12.3 Mobility
Source material may be considered principal threat waste if it is able to migrate to
groundwater, surface water, the air, or acts as a source for direct exposure. Amongst
metal contaminants, mercury has a unique chemistry where mobility of mercury varies
from highly immobile to highly mobile depending on the form of mercury present, and
the existence of specific bio-geochemical conditions that promote methylation of
inorganic mercury.
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Mercury in surface water and sediment at OU-2 is mobile under current conditions due
to biological and chemical transformation processes (methylation) that occur near the
surface water-sediment interfaces of OU-2. Mercury transport potential is also high due
to the suspended sediment loads present in OU-2 surface water. Available OU-2 data
show that these suspended sediments contain bound mercury that can be transported
offsite in surface water flowing from the Basin to the Tombigbee River. The geochemical
and ecological factors that influence how mercury moves and changes form in the OU-2
environment can be changed which directly effects the methylation process and
therefore the mobility. Mobility mechanisms associated with the potential for wind-driven
resuspension, groundwater seepage, interchanges at the surface water-sediment
interface, and variation in geochemical conditions is restricted to the Basin and Round
Pond.
Water leaving the Basin through the gated discharge channel was collected during five
flood events at varying elevations throughout the flood events in 2009 and 2010. The
average dissolved mercury concentration was 0.00769 |jg/L, which is less than the
WQC of 0.012 |jg/L. A mass balance indicated that the mercury concentration in the
Tombigbee River at the confluence with the Basin would not exceed the WQC.
The mobility of mercury from sediment is also limited by the presence of an
uncontaminated clay layer, which lies beneath the Basin and Round Pond. Cores within
the sediment indicate a consistent layer of clay beneath the sediments. Some sandy
zones within the clay or thin sand layers were noted in the cores, but these zones are
not interconnected and clay was observed above and below these zones. Groundwater
results from monitoring wells surrounding OU-2 show that mercury, DDTR, and HCB in
sediments do not act as a continuing source to groundwater or the Tombigbee River via
the groundwater pathway, because COC concentrations above screening levels were
not detected in groundwater associated with OU-2. Core data collected within the Basin
during the Rl further support that mercury in sediment is not a continuing source to
groundwater. The core results collected in 2010 indicate that mercury does not fully
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penetrate the sediment deposits. A pathway from the sediment to the underlying aquifer
is not complete and is expected to remain incomplete.
HCB and DDTR have very limited solubility and would not be very mobile within OU-2,
based on literature values for solubility (HCB solubility in water = 5 parts per billion; DDT
solubility in water = 1.2 parts per billion in water). Mobility of these compounds within
OU-2 is primarily due to movement of soil or sediment particles containing bound HCB
or DDTR.
The volatility of non-elemental mercury, DDTR, and HCB are low so that volatilization to
air is not a significant pathway. COCs in the sediments are not a source for migration to
air.
2.12.4 Containment
Sediment caps have been approved by the EPA for remediation at many sites and are
generally accepted as reliable containment for contaminated sediment. The Steady-
State Model (Lampert and Reible, 2008), referred to as the Reible model, was used to
evaluate whether a cap would be effective as an isolation barrier at OU-2. Varying cap
materials were modeled under mid-level, less, and more conservative scenarios. The
results show the sediments at OU-2 can be effectively isolated through in-situ capping.
2.12.5 Source Material
Source material is defined as a material that acts as a reservoir for migration of
contamination to groundwater, to surface water, to air, or acts a source for direct
exposure. Typical forms of source wastes identified in the NCP, such as liquid wastes,
drums, tanks or free product are not present at OU-2. COCs in sediment and surface
water do not act as a reservoir for migration to groundwater or air, as discussed above.
Although sediment contamination is contributing to surface water contamination at the
Site, it has not been shown to cause an exceedance of the WQC in surface water
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beyond the OU 2 boundaries, as shown in the 2009-2010 sampling of water discharge
from OU-2.
2.12.6 Summary of Principal Threat Waste Analysis
The COCs in sediments at OU-2 are not highly mobile outside of OU-2, can be reliably
contained, and do not pose an acute risk to human health or the environment. Although
the mercury contaminated sediments meet the definition of a source material, the
sediments do not contain elemental mercury and only a small percentage of the
samples have mercury concentrations exceeding remedial goals by two orders of
magnitude. These exceedances are widely scattered throughout the Basin and mercury
concentrations in OU-2 have been shown to be very heterogeneous. Mercury, DDTR,
and HCB can be reliably contained through effective capping. The conditions that favor
mercury methylation are changed when capped because the geochemical conditions
that favor methylation are changed. The EPA believes that mercury at OU-2 is
unclassifiable as either a principal threat waste or low level threat waste. The principal
threat waste characterization was not applied to DDTR and HCB in OU-2 because of
the low mobility and toxicity of these compounds in OU-2.
2.13 SELECTED REMEDY
2.13.1 Summary of the Rationale for the Selected Remedy
Five alternatives for remediation of sediments at OU-2 were compared in the previous
section. No Action (Alternative 1) will result in unacceptable risk to human health and
the environment. Dredging (Alternative 3) can be expected to result in adverse short-
term impacts, such as increases in fish tissue and surface water concentrations of
mercury. Dredging may also not be effective in the long term based on the amount of
resuspension and residual concentrations associated with dredging and debris removal.
Dredging is also a more costly alternative. There is more certainty that in situ or dry
capping or a combination of the two (Alternatives 2A, 2B, and 2C), will be protective of
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human health and the environment, will comply with ARARs, and would effectively
isolate the sediment from humans and the environment. Preliminary model results,
based on current information and assumptions discussed in the FS, predicted that
capping would be effective in the long term. While the costs of in situ capping
(Alternative 2A) are comparable to dry capping (Alternative 2C) or a combination of the
two (Alternative 2B), there is less uncertainty with the implementation of Alternative 2A.
Uncertainties associated with Alternatives 2B and 2C include disruption due to flooding.
Based on the information currently available, the EPA believes that Alternative 2A
meets the threshold criteria and provides the best balance of tradeoffs among the other
alternatives with respect to the balancing and modifying criteria.
2.13.2 Description of the Selected Remedy
• Multi-layered Cap. A multi-layered cap applied in-situ over the areas of sediment
exceeding the sediment cleanup levels (Figure 39), approximately 80 acres. The
cap will consist of three layers: 1) a mixing zone, 2) an effective cap material
layer, and 3) a habitat layer. The cap materials and thickness will be determined
during remedial design. Reactive materials may be used to reduce the potential
for contaminants to migrate through the cap. The cap will meet the following
criteria:
o The cap material will be physically and chemically compatible with the
environment in which it is placed,
o In habitat areas, the uppermost layers of caps will be designed using
suitable habitat materials and, if needed, armoring to prevent erosion. Cap
thickness may vary due to gradient in the basin to prevent sloughing and
erosion.
o Geotechnical parameters will be evaluated to ensure compatibility among
cap components, native sediment, and surface water
o The placement method will minimize short-term risk from the release of
contaminated pore water and resuspension of contaminated sediment
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during cap placement,
o The cap material will immobilize the COCs and have a cap life of at least
100 years or more.
• Additional Sampling and Analyses. Additional sampling and analyses will be
performed in the channel connecting Round Pond to the Basin and the perimeter
of the Round Pond floodplain soils that are often inundated; and the former
wastewater and discharge ditch to further refine the remedial footprint.
• Institutional Controls. ICs, including deed and use restrictions currently in place
as a result of OU-1, will be amended to include the OU-2 remedial footprint and
use restrictions. Also, engineering controls (ECs), such as warning signs,
including fish advisory signage, fencing and security monitoring to restrict access
and prevent exposures to human receptors. Water levels will be managed
through the berm and gate system through the completion of construction to
maintain a consistent water level for equipment mobility and limit the influence of
flooding.
• Construction Monitoring. Construction monitoring will be designed to ensure
design plans and specifications are followed in the placement of the cap and to
monitor the extent of any contaminant releases during cap placement.
Construction monitoring will likely include interim and post-construction cap
material placement surveys, sediment cores, sediment profiling camera, and
chemical resuspension monitoring for contaminants. In the initial period
following cap construction, sediment samples will be taken to confirm the
cleanup levels were achieved and benthic community assessment will be
performed to evaluate restoration efforts.
~ Maintenance. Maintenance of the in-situ cap will include the repair and
replenishment of the layers where necessary to prevent releases of
contaminants.
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~ Long-Term Monitoring. Long-term monitoring will include physical, chemical, and
biological measurements in various media to evaluate long-term remedy
effectiveness in achieving remedial action objectives (RAOs), attaining cleanup
levels, and in reducing human health and environmental risk. In addition, long-
term monitoring data is needed to complete the five-year review process.
~ Depending on the results of this characterization, these areas may require
installation of a cap
Because this Remedy will result in hazardous substances, pollutants, or contaminants
remaining on-Site above levels that allow for unlimited use and unrestricted exposure, a
CERCLA statutory review would be conducted every five years after the completion of
remediation to ensure that the remedy is, or will be, protective of human health and the
environment.
2.13.3 Summary of the Estimated Costs
The Selected Remedy, Alternative 2A's estimated cost is $13,400,000 - $21,500,000.
The cost range is based upon different reactive materials, containing sequestering
materials, that may be used to reduce the potential for contaminants to migrate through
the cap. Table 30 shows the estimated cost summary for the Selected Remedy. The
cost summary is based on the capital and annual operating and maintenance cost to
implement the remedy. The information in the cost summary is based on the best
available information regarding the anticipated scope of the selected remedy. Changes
in the cost elements are likely to occur as a result of new information and data collected
during the engineering design of the remedial alternative. Changes in cost for the
selected remedy may be documented in the Remedial Design, an Explanation of
Significant Differences, or an Amendment to the ROD depending upon NCP
requirements for the change in question. Net present values are estimated using a
discount rate of 7% and an operating period of 30 years. Costs incurred beyond the 30
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years were negligible for this project. The accuracy of the cost estimates shall be within
+50 percent to -30 percent.
2.13.4 Expected Outcomes of the Selected Remedy
The remedial action objectives address the exposure pathways and contaminant levels
in the exposure media. The Selected Remedy, Alternative 2A, is expected to achieve
the RAOS with the completion of the cap placement and natural replacement of the
current generation offish. The RAOs are designed to allow the reduction of mercury,
HCB, and DDTR levels in sediments, soils, biota and surface water such that the overall
risk throughout the Olin Basin will approach that which would be present but for the
historic Olin Mcintosh Plant discharges to the Basin. Recovery, which is estimated to
occur in 10 years, will be achieved when mercury, DDTR, and HCB levels in biota in the
Olin Basin are low enough to be protective of human health and not pose an
unacceptable ecological risk. The EPA has selected Alternative 2A because it is
expected to achieve substantial and long-term risk reduction through isolation and
immobilization of COCs, and is expected to allow the property to be used for the
reasonably anticipated future land use, which is fish and wildlife. OU-2 as seasonally-
flooded wetlands, and as such, is not suitable for human habitation. More than 95
percent of OU-2 is subject to flooding by the Tombigbee River. Under ADEM's Water
Quality Program, the water use classification for the Tombigbee River in the vicinity of
the Olin Basin is Fish and Wildlife.
Unacceptable risk to the community is not anticipated during remedial activities.
Engineering controls such as appropriate PPE will be employed to mitigate short-term
risks during construction. Short-term impacts to the Basin/Round Pond habitat are
expected with the capping alternative. Placement of cap materials could bury benthic
organisms, which could impact feeding of upper trophic level animals, such as some
fish and bird species. Placement of cap materials may also bury large, woody debris,
thus limiting habitat, cover, and food for aquatic species. These impacts are expected to
be temporary. Benthic organisms would recolonize the habitat layer of the cap. A
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temporary increase in turbidity associated with the fine material in the cap material is
expected during cap placement, but this turbidity increase would not be excessive and
would be controlled through the application rate and placement method of the cap. The
short-term adverse effects of capping would be temporary and manageable.
The cleanup levels for each medium (i.e., contaminant specific cleanup levels, basis for
cleanup levels, and risk at cleanup levels (if appropriate) are presented in Table 29.
The cleanup levels are summarized in the following table.
Cleanup Levels
Sediment
Chemical of Concern
Cleanup Level
Mercury
3 mg/kg
HCB
7.6 mg/kg
DDTR
0.21 mg/kg
Surface Water
Chemical of Concern
Cleanup Level
Mercury (dissolved)
0.012 ug/L
DDTR
0.0001 ug/L
HCB
0.0002 ug/L
Floodplain Soil
Chemical of Concern
Cleanup Level
Mercury
1.7 mg.kg
DDTR
0.63 mg/kg
Fish Tissue
Chemical of Concern
Cleanup Level
Mercury
0.2 mg/kg (mosquitofish whole body)
0.3 mg/kg (largemouth bass fillet)
0.28 mg/kg (largemouth bass whole body)
DDTR
0.23 mg/kg (mosquitofish whole body)
0.64 mg/kg (largemouth bass whole body)
2.14 STATUTORY DETERMINATIONS
The remedial action selected for implementation at the Olin OU-2 Site is consistent with
CERCLA and, to the extent practicable, the NCP. The Selected Remedy for Olin OU-2
is protective of human health and the environment, will comply with ARARs and is cost
effective. In addition, the Selected Remedy utilizes permanent solutions and alternate
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treatment technologies or resource recovery technologies to the maximum extent
practicable, and although it does not satisfy the statutory preference for treatment, the
Selected Remedy does significantly reduce the mobility and toxicity that could be
considered as a principal threat. Capping of mercury contaminated sediments has been
demonstrated to be reliable for this type of contamination and provides an element of
treatment to reduce mobility and toxicity (bioavailability) through physical isolation,
stabilization, and chemical immobilization of the contaminants under the cap.
2.14.1 Protection of Human Health and the Environment
An in situ cap serves as a barrier separating other media and potential ecological
receptors from exposure to COCs in the sediment, thereby reducing risk. Risk to
piscivorous birds stems from ingestion offish exposed to mercury or DDTR in
sediments. A cap would prevent fish exposure to the COCs in sediments and diffusion
into surface water. Fish tissue mercury and DDTR concentrations would meet the EPA
recommended fish tissue concentration consumption guideline once the current
generations offish have naturally expired. Risk to piscivorous mammals stems from
incidental ingestion of HCB-contaminated sediments. A cap would provide a barrier
between the piscivorous mammals and the contaminated sediments, eliminating their
exposure pathway. ICs and ECs currently in place would be modified and would
achieve the RAO to reduce or mitigate the current potential risk to humans from
ingestion offish. .
2.14.2 Compliance with ARARs
Section 121(d) of CERCLA, as amended, specifies, in part, that remedial actions for
cleanup of hazardous substances must comply with requirements and standards under
federal or more stringent state environmental laws and regulations that are applicable or
relevant and appropriate {i.e., ARARs) to the hazardous substances or particular
circumstances at a site or obtain a waiver under CERCLA Section 121(d)(4). See also
40 C.F.R. § 300.430(f)(1)(ii)(B). ARARs include only federal and state environmental or
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facility siting laws/regulations and do not include occupational safety or worker
protection requirements. Compliance with OSHA standards is required by 40 C.F.R. §
300.150 and therefore the CERCLA requirement for compliance with or wavier of
ARARs does not apply to OSHA standards.
Under CERCLA Section 121(e)(1), federal, state, or local permits are not required for
the portion of any removal or remedial action conducted entirely on-site as defined in 40
C.F.R. §300.5. See also 40 C.F.R. §§ 300.400(e)(1) & (2). Also, on-site CERCLA
response actions must only comply with the "substantive requirements," not the
administrative requirements of a regulation. Administrative requirements include permit
applications, reporting, record keeping, and consultation with administrative bodies.
Although consultation with state and federal agencies responsible for issuing permits is
not required, it is recommended for determining compliance with certain requirements
such as those typically identified as Location-specific ARARs.
In accordance with 40 C.F.R. § 300.400(g)(5), the EPA and State of Alabama have
identified the ARARs and TBCs for the selected remedy. Table 31-33, lists respectively,
the Chemical-specific, Location-specific and Action-specific ARARs for the selected
remedy. The Selected Remedy is expected to attain all identified ARARs and a statutory
waiver is not necessary. See 40 C.F.R. § 300.430(f)(5)(ii)(B).
2.14.3 Cost Effectiveness
In the EPA's judgment, the Selected Remedy is cost-effective because the remedy's
costs are proportional to its overall effectiveness (see 40 CFR 300.430(f)(1)(ii)(D)). This
determination was made by evaluating the overall effectiveness of those alternatives
that satisfied the threshold criteria (i.e., that are protective of human health and the
environment and comply with all federal and any more stringent ARARs, or as
appropriate, waive ARARs). Overall effectiveness was evaluated by assessing three of
the five balancing criteria - long-term effectiveness and permanence; reduction in
toxicity, mobility, and volume through treatment; and short-term effectiveness, in
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combination. The overall effectiveness of each alternative then was compared to the
alternative's costs to determine cost-effectiveness. The relationship of the overall
effectiveness of the selected remedial alternative was determined to be proportional to
its costs and hence represents a reasonable value for the money to be spent.
2.14.4 Utilization of Permanent Solutions and Alternative Treatment (or Resource
Recovery) Technologies to the Maximum Extent Practicable
The NCP establishes an expectation that the EPA will use treatment to address the
principal threat posed at a site wherever practicable (Section 300.430(a)(1)(iii)[A]). In
practice, the "principal threat" concept is applied by the EPA to the characterization of
"source materials" at a Superfund site. A source material includes or contains
hazardous substances, pollutants or contaminants that act as a reservoir for migration
of contamination to ground water, surface water or air, or acts as a source for direct
exposure. Principal threat wastes are those source materials considered to be highly
toxic or highly mobile that generally cannot be reliably contained, or would present a
significant risk to human health or the environment should exposure occur. The Olin
OU-2 mercury contaminated sediments are not readily classifiable as principal threat
wastes despite the inherent toxicity of mercury and demonstrated mobility which has
contaminated surface water. However, capping alternatives have been demonstrated to
be reliable containment remedies for this type of contamination.
The selected remedy for OU-2 does not satisfy the statutory preference for treatment as
a principal element of the remedy. Because of the relatively high volume of sediments
involved, and the concentrations of mercury involved, treatment of sediments was not
considered practical. The toxicity, mobility and volume of mercury in sediments will be
significantly reduced through physically and chemically isolating the contaminated
sediments from the aquatic environment. In-situ caps are generally accepted as reliable
containment for contaminated sediment.
Because this remedy will result in hazardous substances, pollutants, or contaminants
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remaining on-Site above levels that allow for unlimited use and unrestricted exposure, a
CERCLA statutory review is required and will be conducted every five years after
initiation of remediation to ensure that the remedy is, or will be, protective of human
health and the environment. Based upon the results of those reviews, as well as on-
going monitoring, modifications to the Selected Remedy may be required to ensure
remedy effectiveness and protection of human health and the environment.
2.15 DOCUMENTATION OF SIGNIFICANT CHANGES
The Proposed Plan was released for public comment in May 2014. It identified
Alternative 2A, in-situ capping, as the Preferred Alternative for contaminated sediments
and soils; and presented cleanup levels or remedial goals for COCs. During the public
comment period, the EPA received comments and additional fish data from Olin that
resulted in additional evaluation of the RGs and the selection of cleanup levels.
The ecological RGs presented in the Proposed Plan were selected based upon the
RGO Report, which was prepared in accordance with the EPA ecological risk
assessment methodologies and is consistent with the NCP and the EPA guidance
documents or other scientific literature. The following table presents the cleanup levels
selected in the ROD and whether modifications were made to the RG ranges and
cleanup levels presented in the Proposed Plan. The EPA evaluation that resulted in
modifications to the RGs presented in the Proposed Plan is documented in Appendix 1
of this ROD.
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Sediment
Mercury
3 mg/kg
Same as Proposed Plan
HCB
7.6 mg/kg
Same as Proposed Plan
DDTR
0.21 mg/kg
0.33 - 1.7 mg/kg in Proposed Plan
Surface Water
Mercury
(dissolved)
0.012 ug/L
Same as Proposed Plan
DDTR
0.0001 ug/L
Not in Proposed Plan
HCB
0.0002 ug/L
Not in Proposed Plan
Floodplain Soil
Mercury
1.7 mg/kg
Not in Proposed Plan
DDTR
0.63 mg/kg
0.039 - 0.25 mg/kg in Proposed Plan
Fish Tissue
Mercury
0.2 mg/kg (mosquitofish/silverside)
0.3 mg/kg (largemouth bass fillet)
0.28 mg/kg (largemouth bass whole body)
Not in Proposed Plan
Same as Proposed Plan
Not in Proposed Plan
DDTR
0.23 mg/kg (mosquitofish/silverside)
0.64 mg/kg (largemouth bass)
Not in Proposed Plan
Same as Proposed Plan
Fish Tissue RGs
Although the RGO Report developed sediment RGs for a variety of piscivorous wildlife
to reduce their risk from exposure to chemicals of concern through ingestion of
contaminated media, the RGO report did not develop RGs to protect fish from the COCs
they accumulate in their bodies through bioaccumulation and direct exposure to water
and sediment. Because the Proposed Plan did not present fish tissue RGs for protection
of ecological receptors (fish and piscivorous wildlife), the fish tissue RGs based on
protection of ecological receptors are summarized below.
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Mercury in Fish Tissue
The fish tissue mercury RG range (0.11 mg/kg - 0.58 mg/kg) based on protection of
piscivorous wildlife was presented in the RGO report, but was not presented in the
Proposed Plan. The mercury cleanup level for whole body forage fish based on
protection of piscivorous birds falls within the RG range presented in the RGO report.
The mercury RG for whole body predatory fish is based on protection of fish
themselves, and was not presented in either the RGO Report or the Proposed Plan.
Derivation of RGs for whole body forage fish and whole body predatory fish are detailed
in Appendix 1 of the ROD.
Cleanup Levels Selected:
• Mercury in whole body forage fish: 0.20 mg/kg based on protection of piscivorous
birds feeding on forage fish
• Mercury in whole body predatory fish: 0.28 mg/kg based on protection of
predatory fish
DDTR in Fish Tissue
Ecological RGs for DDTR in fish tissue are based on protection offish in OU-2, and
were not presented in either the RGO Report or the Proposed Plan. The DDTR whole
body fish tissue level of 0.64 mg/kg in tissues of predatory fish and 0.23 mg/kg in
tissues of forage fish, is based on protection of predatory fish. The derivation of the
DDTR RGs based on protection offish is detailed in Appendix 1 of the ROD.
Cleanup Levels Selected:
• DDTR in whole body forage fish: 0.23 mg/kg based on protection of predatory
fish feeding on forage fish
• DDTR in whole body predatory fish: 0.64 mg/kg based on protection of predatory
fish
Sediment RGs for DDTR
The EPA re-evaluated sediment RGs for DDTR based on the fish tissue RGs. As result
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of the evaluation, the EPA determined that the sediment level needed to be protective of
predatory fish is 0.21 mg/kg. Site-specific bioaccumulation relationships developed for
fish at Olin OU-2 suggest that a sediment DDTR concentration of 0.21 mg/kg results in
a protective fish tissue concentration of 0.64 mg/kg. The RG range presented in the
Proposed Plan was 0.33 - 1.7 mg/kg.
Surface Water RGs for DDTR and HCB
In the Proposed Plan, the RAO includes a statement that the surface water will be
restored to meet water quality standards. A numeric standard was presented for
mercury, but not for the other COCs. For clarification, the EPA added the numeric
standards for DDTR and HCB.
Floodplain Soil RG for Mercury
The floodplain mercury RG range (1.1 mg/kg - 1.9 mg/kg) based on protection of
insectivorous birds was presented in the RGO report, but was not presented in the
Proposed Plan. The mercury cleanup level for floodplain soil based on protection of
insectivorous birds falls within the range presented in the RGO report.
Floodplain Soil RG for DDTR
The RGO report derived RGs for floodplain soil based on risk to insectivorous birds, as
represented by Carolina wren. TRVs used to derive RGs for the wren were selected
from the information presented in the EPA Eco-SSL guidance for DDTR (EPA, 2007),
and were the same TRVs used to derive RGs for piscivorus birds at OU-2. The TRVs
selected for evaluation of piscivorous birds were based on analysis of data considering
all toxicological endpoints, including egg-shell thinning. However, egg-shell thinning
does not appear to be an important mechanism for reproductive impairment in terrestrial
birds other than raptors, so use of this as a toxicological endpoint for RG development
for terrestrial songbirds is not appropriate. Based on evidence that suggests that
eggshell thinning is not a relevant toxicological endpoint for songbirds, the EPA re-
evaluated the TRVs and determined that the soil level needed to be protective is 0.63
mg/kg. The RG range presented in the Proposed Plan was 0.039 - 0.25 mg/kg. The
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derivation of the DDTR RG for floodplain soil to be protective of insectivorous birds is
detailed in Appendix 1 of the ROD.
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PART 3
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Olin Mcintosh OU-2 Site
PART 3: REFERENCES
AMEC. 2011a. Part 1 Remedial Investigation Addendum and Enhanced Sedimentation
Pilot Project Annual Report, Year 2 Results. Revision 2. Operable Unit 2,
Mcintosh, Alabama. November 14.
AMEC. 2011b. Part 2 Updated Ecological Risk Assessment. Revision 2. Operable Unit
2, Mcintosh, Alabama. November 14.
AMEC. 2011c. Part 3 Updated Human Health Risk Assessment. Revision 2. Operable
Unit 2, Mcintosh, Alabama. November 14.
AMEC. 2012a. Remedial Goal Option Report for the Development of Preliminary
Remediation Goals in Sediment and Floodplain Soils, Revision 3. Operable Unit 2,
Mcintosh, Alabama. July 6.
AMEC. 2012b. Feasibility Study, Revision 2. Operable Unit 2, Mcintosh, Alabama.
October 31.
Barbour, M.T., J. Gerritsen, B. D. Snyder, and J. B. Stribbling, 1999. Rapid
Bioassessment Protocols for Use in Streams and Wadable Rivers: Periphyton,
Benthic Macroinvertebrates, and Fish, Second Edition. EPA 841-B-99-002. U.S.
Environmental Protection Agency; Office of Water; Washington, D.C.
Beaver, D. 1980. Recovery of an American robin population after earlier DDT use. J
Field Ornithol 51: 220-228.
Beckvar, N., T.M. Dillon, and L.B. Read. 2005. Approaches for linking whole-body fish
tissue residues of mercury or DDT to biological effects thresholds. Environ Toxicol
and Chem, 24(8): 2094-2105.
Gill, H., L. Wilson, K. Cheng, and J. Elliott. 2003. An assessment of DDT and other
chlorinated compounds and the reproductive success of American robins (Turdus
migratorius) breeding in fruit orchards. Ecotoxicol 12: 113-123.
Lampert, D.J. and D. D. Reible, 2008. Steady-State Cap Design Model. Version 1.13.
November 12.
Mettee, M. F., P. E. O'Neil, and J. M. Pierson, 1996. Fishes of Alabama and the Mobile
Basin. Monograph 15, Geological Survey of Alabama. Oxmoor House:
Birmingham. 820 pp.
MACTEC. 2007. Enhanced Sedimentation Pilot Project (ESPP) Baseline Sampling.
Operable Unit 2, Olin Corporation, Mcintosh, Alabama. June 8, 2007.
MACTEC. 2009a. Enhanced Sedimentation Pilot Project Annual Report - Year 1
Results, Operable Unit 2, Mcintosh, Alabama, March 31, 2009.
April 2014
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MACTEC. 2009b. Remedial Technologies Screening and Alternatives Development in
Support of a Feasibility Study. Operable Unit 2, Mcintosh, Alabama. November 24,
2009.
Rasmussen. 1996. University of Florida Book of Insect Records. Chapter 20 Least
Oxygen Dependent. Available: (http://ufbir.ifas.ufl.edu/Chap20.htm)
Soil and Water Conservation Society of Metro Halifax. 2008.
(http://www.chebucto.ns.ca/ccn/info/Science/SWCS/ZOOBENTH/BENTHOS/xxv.ht
mi).
URS. 2002. OU-2 RGO Support Sampling Report. Mcintosh Plant Site, Olin
Corporation, Mcintosh, Alabama. April 15, 2002.
USEPA. 1990. The National Oil and Hazardous Substances Pollution Contingency
Plan (NCP) Final Rule at 55 Fed. Reg. 8666 (March 8, 1990).
USEPA. 1991. A guide to principal threat and low-level threat wastes. Superfund
Publication 9380.3-06FS. Office of Solid Waste and Emergency Response.
November, 1991.
USEPA. 1993. Wildlife Exposure Factors Handbook Volume I, United States
Environmental Protection Agency, Office of Research and Development,
EPA/600/R-93/187a, December 1993.
USEPA. 1996. Soil Screening Guidance: Technical Background Document.
EPA/540/R-95/128. July.
USEPA. 1997. Rules of Thumb for Superfund Remedy Selection. Office of Solid Waste
and Emergency Response. EPA 540-R-97-013. August 1997.
USEPA. 2002b. Supplemental Guidance for Developing Soil Screening Levels for
Superfund Sites, U.S. Environmental Protection Agency, December 2002.
USEPA. 2004. Risk Assessment Guidance for Superfund, Volume I: Human Health
Evaluation Manual Part E, Supplemental Guidance for Dermal Risk Assessment,
OSWER 9285.7-02EP, July 2004.
USEPA. 2005. Contaminated Sediment Remediation Guidance for Hazardous Waste
Sites." USEPA, Office of Emergency and Remedial Response, Washington, DC.
EPA-540-R-05-012, OSWER 9355.0-85, December.
USEPA. 2007. Ecological Soil Screening Levels for DDT and Metabolites. Office of
Solid Waste and Emergency Response, U.S. Environmental Protection Agency,
Washington, DC. OSWER Directive 9285.7-57.
April 2014
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USEPA. 2009. Olin Mcintosh OU-2 ERA Data Use Specifications, EPA Region 4.
Presentation, December.
USEPA. 2010. Regional Screening Level Tables, May 2010
WCC. 1993. Remedial Investigation Report. Mcintosh Plant Site, Olin Corporation,
Mcintosh, Alabama. February.
WCC. 1994. Additional Ecological Studies of OU-2 Work Plan. Mcintosh Plant Site,
Olin Corporation, Mcintosh, Alabama. June.
WCC. 1995. Ecological Risk Assessment of Operable Unit 2. Mcintosh Plant Site, Olin
Corporation, Mcintosh, Alabama. May 1995.
WCC. 1996. Feasibility Study, Operable Unit 2. Mcintosh Plant Site, Olin Corporation,
Mcintosh, Alabama. February 1996.
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TABLES
NOTICE
Data are used for reference purposes only. U.S. EPA makes no warranty
or guarantee as to the content (the source is often third party), accuracy,
timeliness, or completeness of any of the data provided, and assumes no
legal responsibility for the information contained in these tables.
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Record of Decision
Olin Mcintosh OU-2 Site
Table 1. Data Use Matrix for Current Olin OU-2 Reports
2010 Groundwater
r» l
2011 Rl Addendum
<
Q
LL
a
~
o
T
C
c
o
2011 Updated HHRA
2012 RGO Report
2012 FS
Post-FS Data Usage
(not included in
previous reports)
Remarks
Surface Sediment
1991/1992
..
©
©
..
~
©
..
Qualitative use of DDTR & HCB data; data was collected in a phased approach
that began in 1991 and extended into 1992
1994
__
©
~
__
~
__
__
Used for determining BSAFs for vertebrate prey collected in 1994
1995
__
©
©
__
__
__
__
2001
__
©
~
__
~
__
__
Used for determining BAFs/BSAFs for aquatic insects collected in 2001
2006
~
©
©
~
~
Sediment discussed qualitatively for HHFRA because Region 4 considers
incomplete exposure pathways to sediment
2008
..
~
~
©
~
~
..
Sediment discussed qualitatively for HHFRA because Region 4 considers
incomplete exposure pathways to sediment
2009
~
~
~
©
~
~
Sediment discussed qualitatively for HHFRA because Region 4 considers
incomplete exposure pathways to sediment
Subsurface Sediment
1991/1992
©
__
1995
©
__
2009
~
~
__
__
~
__
Floodplain Soil
1991/1992
__
©
©
©
__
__
__
1994
__
©
©
©
__
__
__
2010
__
~
~
~
~
~
__
Surface Water
1991
__
__
~
~
__
__
__
1991 used for HCB and DDTR FIFIRA exposures
1994
__
__
~
~
__
__
__
1994 used for FICB and DDTR FIFIRA exposures
1995
__
2006
__
2008
__
__
Fig and MeFIg
2009
__
__
Fig and MeFIg
2010
__
Surface Water (Gate Overflow)
2009-2010
__
~
__
__
__
~
__
Pore Water
1995
__
2009
__
~
__
__
__
~
__
Groundwater
1991
__
2008
~
~
—
—
..
~
..
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Table 1. Data Use Matrix for Current Olin OU-2 Reports (continued)
2010 Groundwater Report
2011 Rl Addendum
2011 Update ERA
2011 Updated HHRA
2012 RGO Report
2012 FS
Post-FS Data Usage (not
included in previous
Remarks
Fish Tissue
Largemouth Bass
(whole body)
1991
__
©
__
1994
__
©
__
2001
__
©
__
2008
__
~
~
__
~
__
__
2010
~
2010 LMB data used to refine remedial goals for Great Blue Heron post
FS
Largemouth Bass Fillet
1986
__
1991
__
©
__
2001
__
©
__
~
__
__
__
Used to develop exposure point concentration for DDTR
2003
__
©
__
2006
__
~
__
2007
__
~
__
2008
__
~
__
~
__
__
__
Used to develop exposure point concentrations for Hg and HCB
2010
~
2010 fillet data used qualitatively post FS to estimate sediment levels
protective of human health
Bluegill (whole body)
1995
__
2008
__
~
~
__
~
__
__
Used to develop exposure point concentrations for Hg and HCB
2010
~
2010 bluegill data used to refine BSAF models for forage fish to derive
remedial goals post-FS
Mosquitofish (whole body composites)
1994
__
2001
__
©
~
__
~
__
__
Used to develop exposure point concentration for DDTR
Silversides (whole body composites)
2008
__
~
~
__
~
__
__
Used to develop exposure point concentrations for Hg and HCB
2010
~
2010 silversides data used to refine BSAF models for forage fish to
derive remedial goals post-FS
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Table 1. Data Use Matrix for Current Olin OU-2 Reports (continued)
2010 Groundwater
r» l
2011 Rl Addendum
2011 Update ERA
2011 Updated HHRA
2012 RGO Report
2012 FS
Post-FS Data Usage
(not included in
Remarks
Other Biota
Aquatic Insects
1994
__
©
__
__
__
__
__
1995
__
©
__
__
__
__
__
2001
__
©
~
__
~
__
__
Terrestrial Insects and Spid
ers
1994
__
©
~
__
~
__
__
1995
__
©
~
__
~
__
__
2010
__
~
~
__
~
__
__
Crayfish
1994
__
©
~
__
~
__
__
Bull Frogs
1994
__
©
~
__
~
__
__
Mussels
1994
__
__
__
__
__
__
__
Raccoon and Little Blue Heron (whole bod'
t)
1994
__
©
~
__
~
__
__
Terrestrial Vegetation
2010
..
~
~
..
~
..
..
Note: Symbols denote ~ Data used Quantitatively; © Data used Qualitatively; - Data not used
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Table 2. Analytical Results Summary for Historical Surface Water, Sediment, and Soil Samples
Range of Concentrations -1991
Range of Concentrations -
Range of Concentrations -
Range of Concentrations -19^5
Range of Concentrations -
Surface Water
shallow samples deep samples
1992
1<>94
surface samples bottom samples
2001
Mercury (unfiltered)
0 26 - 1 5 pg L 0,45-1.8 pg/L
na
0.23-3.6 fig/L
0.447 - 1.65 fig/L 0.451 -4.61 fig/L
na
Mercury (filtered)
-0 2 fig L <0.2 pg/L
na
0.00642 - 0.0367 fig/L 0.00720 - 0.0118 pg/L
na
Methylmereury funfiltered)
na
na
0.00245 - 0,00431 pg/L 0.00-109 - 0.0121 pg.L
na
Methylmercuiy (filtered)
na
na
0.000359 - 0.000576 pg/L 0.000233 - 0.00174 pg/L
na
Dissolved Oxygen
5 - 10 5 mg'L 3.1 -6.4mg/L
na
4.7 - 8,0 mg/L 0,1 ~ 5.7 mg/L
na
Dissolved Organic Carbon
na
na
na 3.7-7.0 mg/L
na
4,4'-DDD
-0 1 pgL
0.0286 - 0.092 pg/L
na
na
Pesticides 4.4'-DDE
- 0,1 fig L
0.018-0.0983 fig/L
na
na
4,4'-DDT
0,1 pg'L
na
-0.00047 - 0.0082 fig/L
na
na
Hexachlorobenzene
10 fig L
na
0.00313 -0.0442 pg'L
na
na
pH
" 2 - srv " 0" - " 66
na
7.1-8.4 6.5 - T.8
na
Specific Conductance
1 91 - 2 13 mS cm 2 0b - 2 19 mS cm
na
na na
na
Temperature
28 6 - 34 9 'C 28 5 - 2° 3 C
na
29 ~ - 32 2 C 27.8 -30 5 "C
na
Iron
na
na
na
0 281 - 0 452 mg L na
na
Manganese
na
na
na
0 083 - 0 259 mg L na
na
Total Organic Carbon
6,1-15 8mg'L 5.6 -8.9mg/L
na
na
na 4.0 - 6 0 mg/L
na
Range of Concentrations -
Range of Concentrations -
Range of Concentrations -
Surfieial Sediment
Range of Concentrations - 1991
1992
PJ94
Range of Concentrations - 1995
2001
Mercury
0,19-290 mg/kgdw
na
18.6 - 113 mg kg dw
0,844 - 780 mg kg dw
3.4-590mg/kgdw
Methylmercuiy
na
na
na
0.00191 -0.255 mg;kg dw
na
Methylmereury °o
na
na
na
0.012 - 0.26"°o
na
Total Sulfate
-130 »1,360 mg 'kg dw
na
na
na
na
Total Sulfide
259 - 2,830 mg kg dw
na
na
na
na
DDTr
0 2~2 - 6 9 mg kg dw
na
0.6"" - 4.01 mg kg dw
na
0.082 - 25.9 mg'kg dw
DDTR
0.775 - 11,8 mg/kg dw
na
1.41 - "M4 mg kg dw
na
0.16-51.0 mg'kg dw1
Pesticides 4,4'-DDD
0 12-18 mg kg dw
na
na
na
na
4,4'-DDE
0 1-14 mg kg dw
na
na
na
na
4.4'-DDT
0 0^2 - 4 mg kg d»
na
na
na
na
Hexachlorobenzene
0 6~ - 265 mg kg dw
na
na
na
- 0 01 - ^3 mg kg dw
Total Organic Carbon
6,000 - 80,500 mg kg dw
na
3,220 - 16.000 mg kg dw
5,600 - 53.300 mg'kg dw
2,600 - 1 "0.000 mg kg dw
pH
6 93 - ^.3^
na
na
na
na
Range of Concentrations -
Range of Concentrations -
Range of Concentrations -
Floodplain Soils
Range of Concentrations - 1991
1992
1994
Range of Concentrations - 1995
2001
Mercury
na
- 0 15 J » 6.6 J mg kg dw
2 ~ - 25 mg kg dw
na
24 » 480 mg/kg dw
2,4'-DDD
na
na
0 032™ D - 28 mg kg dw
na
0 2 - I ~ mg kg dw
2,4'~DDE
na
na
0 163 D - 43 mg kg dw
na
1.5 - 5.7 mg/kg dw
2,4!-DDT
na
na
0 0269 D - 2" mg'kg dw
na
0 032 - 0 096 mg kg dw
4Jf~DDD
Pesticides
na
na
0 0326 D - 11 mg kg dw
na
0 34 - 2 4 mg kg dw
4,4f-DDE
na
na
0,413 D - 41 mg/kg dw
na
1.2 - 4 9 mg kg dw
4,4'~DDT
na
na
0 0199 D - 31 mg kg dw
na
0 12 - 0 36 mg 'kg dw
DDTr
na
na
0 52 - 83 mg kg dw
na
1 66 - " 66 mg kg dw
DDTR
na
na
0 "39 - 1 *"¦" mg kg dw
na
3 36 - 1^ 1 mg kgdw
Hexachlorobenzene
na
<0.5 - 2.7 mg/kg dw
0 051 - 0 6" mgkg dw
na
0 032 - 0 16mgkg dw
Total Organic Carbon
na
na
na
na
48,000 - 130,000 mg kg dw
Notes:
0 - degrees Celsius
D - sample was diluted
DDD - dichlorodiphenyldiehloroethane
DDE - diehlorodiphenyldiehloroethylene
DDT - diehlorodiphenjltrichloroethane
DDTr - sum of 4.4' - isomers DDT, DDD. DDE
DDTR - sum of 2.4' - and 4.4' - isomers DDT, DDD, DDE
dw - dry weight
J - estimated
mg'kg - milligrams per kilogram
ing/L - milligrams per liter
mS/cm - milliSiemens per centimeter
na - not analyzed for this constituent
|ig/L - microgram per liter
- - less than the reporting limit
% - percent
Ranges reported for surfieial sediment samples include samples collected within the upper 6 inches,
1 - Where only DDTr was reported, an estimate of DDTR is provided based on a ratio of DDTR to DDTr where both are available (DDTR
DDTr* 1.97).
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Record of Decision
Olin Mcintosh OU-2 Site
Table 3. Floodplain Soil Analytical Results (year 2010)
Analyte
Grain Size
Gravel
Sand
Silt/Clay/Colloids
Number of
Samples
3
3
3
Units2
%
0/
/o
0/
/o
2010
Range of Concentrations
0.06-2.5
3.3-24.7
72.8 -95.4
Mean
Concentration
1.5
13
85.7
Median
Concentration
1.3
11
88.9
Total Organic Carbon
39
mg/kg
4,200 - 298,000
36,800
26,300
Percent Solids
39
0/
/O
15.1 -78.3
60.5
63
Mercury
39
mg/kg
0.061 -8.9
0.98
0.37
Methylmercury
12
mg/kg
0.000176 -0.00822
0.00275
0.002
Hexachlorobenzene
8
mg/kg
<0.00076 -3.5
0.437
0.0057
DDTR
15
mg/kg
0.0011 -2.21
0.43
0.055
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Record of Decision
Olin Mcintosh OU-2 Site
Table 4. Sediment Data Summary by Transect
Transect
Analysis
Deeper Portion of
Round Pond (n 6)
5 (North, n=l 0)
0 (Northeast, n=l)'
Basin (n 1)
4 (North-central, n=4)
1 (Central, n=14)
2 (South-central, n 13)
3 (South, n S)
Mercury, Total (mg/kg dw)
22.6(14.1 - 32.1)
54.3(24.7- 112)
38.3
29.1
26.6(18.9-35.7)
38.3 (22.6 - 77.6)
57.0(7.1 - 116)
13.8(2.01-20.9)
Methylmercury (mg/kg dw)
0.00562 (0.00451 - 0.00640)
0.0115(0.00310 - 0.0238)
0.00487
0.00431
0.00944 (0.00286 - 0.0257)
0.00615 (0.00265 - 0.0212)
0.00721 (0.00219 - 0.0128)
0.00465 (0.00142 - 0.00756)
% Methylmercury
0.0265 (0.0140 - 0.0379)
0.0223 (0.0100 - 0.0736)
0.0127
0.0148
0.0442(0.0116 - 0.136)
0.0187 (0.00763 - 0.0918)
0.0152 (0.00736 - 0.0425)
0.0406 (0.0161 - 0.0706)
AVS/SEM ratio
47.1 (27.0-69.9)
NA
32.0
80.4
40.5
57.0 (18.7 - 99.0)
67.0 (12.3 - 156)
27.4 (9.93 - 55.6)
Grain Size (%)
Clay
48.0(40.6-56.1)
38.6 (<0.01 - 54.9)
36
66
37.3 (25.6 - 54.8)
39.6 (32.9 - 54.9)
23.0 (9.4 - 35.6)
14.3 (2.7 - 28)
Silt
48.8(41.6-57.2)
49.6(44.6-56.1)
60.9
34
55.3 (36.4 - 70.8)
56.7 (44.9 - 64.4)
51.9(34.2 - 66.8)
53.2 (13.2 - 68.4)
Sand
3.0(1.7-6.3)
11.7(0.1 - 50)
3.1
<0.01
7.4(1.4- 15.6)
3.6 (0.2 - 14.5)
24.9 (2.6 - 56.2)
32.5 (4.3 - 84.1)
Gravel
<0.01
0.1 (<0.01 - 0.6)
<0.01
<0.01
0.1 (<0.01 -0.5)
0.2 (<0.01 - 2.7)
0.2(<0.01 - 1.3)
<0.01
Bulk Density (g/cm3 dw)
1.13(1.07- 1.19)
NA
1.21
1.13
1.31
1.17(0.921 - 1.32)
1.45(1.13-2)
1.55(1.38- 1.77)
Percent Moisture
79.1 (77.4-81.4)
68.2 (<0.1 -78)
70
79.6
76.0 (74.2 - 77.6)
71.7(68.8-78.3)
52.3 (33.1 - 70.6)
40.1 (30.5-59.7)
Pesticides (mg/kg dw)
4,4'-DDD
0.0438 J
NA
NA
NA
<0.0147
0.0541
0.172
0.259
4,4'-DDE
0.0509 J
NA
NA
NA
0.019
0.0839
0.191
0.480
4,4'-DDT
0.0292 J
NA
NA
NA
<0.0147
< 0.0252
0.0368
<0.0569
2,4'-DDD
0.0325 J
NA
NA
NA
0.0099
0.0394
0.233
0.336
2,4'-DDE
0.0652 J
NA
NA
NA
0.0311
0.128
0.507
1.60
2,4'-DDT
<0.0085
NA
NA
NA
<0.0074
<0.0126
<0.0067
<0.0284
DDTr
0.124
NA
NA
NA
0.0190
0.138
0.400
0.739
DDTR
0.222
NA
NA
NA
0.0600
0.305
1.14
2.68
Hexachlorobenzene (mg/kg dw)
NA
NA
NA
NA
0.0267 (0.0221 - 0.0313)
NA
2.49 (0.628 - 5.97)
4.45 (<0.0069 - 8.90)
Sulfate, Total (mg/kg dw)
< 2,200
NA
<1,660
<2,440
NA
< 1,850
<1,650
NA
Sulfide, Total (mg/kg dw)
2,100
NA
1,600
3,300
NA
2,500 J
1,200 (800 - 1,600)
NA
TOC (mg/kg dw)
32,000 (29,000 - 39,000)
29,000 (12,600 - 53,600)
16,300
14,400
22,300 (2,630-60,500)
16,900 (10,700 - 57,700)
5,730 (644 - 10,600)
5,120(1,550- 11,200)
ORP(mV)
-372 (-382 - -360)
-380 (-397 - -352)
-393
-393
-433 (-440 - -423)
-381 (-417- -314)
-365 (-419 - -296)
-361 (-410 - -165)
pH
6.75 (6.29 - 6.91)
6.75 (6.63 - 6.91)
7.20
6.55
7.36 (6.81 - 8.81)
6.84 (6.59 - 7.01)
7.00(6.65 - 7.19)
6.93 (6.81 - 7.00)
Temperature ( C)
23.3 (22.5 - 24.2)
24.5 (22.6 - 27.8)
22.9
24.4
26.1 (24.9 - 26.6)
25.2 (22.4 - 28.3)
25.4 (23.8 - 26.5)
25.9 (22.9 - 27.9)
Notes:
°C - degree Celsius
AVS/SEM - ratio of acid-volatile sulfide to simultaneously extracted metals. One halfofthe reporting limit was used in this calculation when analytical results were less than the reporting limit.
DDD - dichlorodiphenyldichloroethane
DDE - dichlorodiphenyldichloroethylene
DDT - dichlorodiphenyltrichloroethane
DDTr - sumof 4,4'-isomers ofDDD, DDE, and DDT. Zero was used in this calculation when analytical results were less than the reporting limit.
DDTR- sum of 4,4'-DDD; 4,4'-DDE; 4,4'-DDT, 2,4'-DDD; 2,4'-DDE; and 2,4'-DDT. Zero was used in this calculation when analytical results were less than the reporting limit,
dw - dry weight
g/cm3 - gram per cubic centimeter
J - estimated concentration based on data quality evaluation or result between method detection limit and reporting detection limit
mg/kg - milligram per kilogram
mV- millivolt
n - number of samples analyzed for mercury
NA - not analyzed
ORP - oxidation-reduction potential
TOC - total organic carbon
% - percent
< - less than the reporting limit.
1Location between northern and north-central transect.
Round Pond - samples OU2R-SED-101 and 102
Transect 5 - samples OU2B-SED-501 and 502
Transect 0 - sample OU2B-SED-004
Deep hole - sample OU2B-SED-DH
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 5. Sediment Core Analytical Results - Coarse Cores
Number
2009
Depth
Interval
Analyte
of
Samples
Units2
Range of
Concentrations
Mean
Concentration
Median
Concentration
Grain Size
Gravel
13
%
0
1
o
L/i
0.04
0
Sand
Silt/Clay/Colloids
13
13
0/
/o
0/
/o
0.5-63.3
36.8 -99.4
7.4
92.6
2.2
97.6
Percent Solids
11
0/
/o
15.1 -78.3
35.2
29
0 - 1 ft
Mercury
10
mg/kg
0.03 - 121
49.6
23
Hexachlorobenzene
4
mg/kg
<0.034 -330
82.8
1.3
DDTR
4
mg/kg
<0.05 - 156
0.63
0.48
Number
2009
Depth
Interval
Analyte
of
Samples
Units2
Range of
Concentrations
Mean
Concentration
Median
Concentration
Grain Size
Gravel
13
%
0-0
0
0
Sand
Silt/Clay/Colloids
13
13
0/
/o
0/
/o
0.1-49.2
50.9 -99.9
5.4
94.6
1.3
98.8
1 -2ft
Percent Solids
16
0/
/o
25-64
39
35
Mercury
13
mg/kg
0.14-170
29.3
47.3
Hexachlorobenzene
4
mg/kg
<0.035 -320
80
0.063
DDTR
4
mg/kg
<0.1 - 1.01
0.485
0.39
1 of 5
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Record of Decision
Olin Mcintosh OU-2 Site
Table 5. Sediment Core Analytical Results - Coarse Cores (continued)
Number 2009
Depth of Range of Mean Median
Interval Analyte Samples Units2 Concentrations Concentration Concentration
Grain Size
Gravel 13 % 0-0 0 0
Sand 13 % 0.3-35.9 5.9 1
Silt/Clay/Colloids 0/o 64.1 - 99.8 94.1 98.9
_ Percent Solids 13 % 26 -60 40.8 40
2 - 3 ft
Mercury
13
mg/kg
0.13-230
31.5
15
Hexachlorobenzene
4
mg/kg
0.0055- 120
30
0.015
DDTR 4 mg/kg 0.004- 0.23 0.069 0.021
Number 2009
Depth of Range of Mean Median
Interval Analyte Samples Units2 Concentrations Concentration Concentration
Grain Size
Gravel 13 % 0-0 0 0
Sand 13 % 0.1 - 10 3 0.8
Silt/Clay/Colloids 13 0/o 90.99.7 97 99.2
Percent Solids
13
0/
/O
27-65
44.8
46
Mercury
13
mg/kg
0.16-300
42.2
3.1
Hexachlorobenzene
4
mg/kg
<0.0031 -9.9
2.5
0.0185
DDTR
4
mg/kg
<0.04-2.04
0.512
0.02
2 of 5
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Record of Decision
Olin Mcintosh OU-2 Site
Table 5. Sediment Core Analytical Results - Coarse Cores (continued)
Number 2009
Depth of Range of Mean Median
Interval Analyte Samples Units2 Concentrations Concentration Concentration
Grain Size
Gravel 13 % 0-0 0 0
Sand 13 % 0-4.7 0.97 0.55
Silt/Clay/Colloids 0/o 95.3- 99.9 99.1 99.5
Percent Solids 13 % 28 -63 46.8 47
Mercury
13
mg/kg
0.066 -
96.0
17.9
0.25
Hexachlorobenzene
4
mg/kg
0.001 -
0.25
0.092
0.058
DDTR 4 mg/kg 0.0023- 1.50 0.38 0.0056
Number 2009
Depth of Range of Mean Median
Interval Analyte Samples Units2 Concentrations Concentration Concentration
Grain Size
Gravel
10
0/
/o
0-0
0
0
Sand
10
0/
/o
0.2-2.1
0.9
0.6
Silt/Clay/Colloids
10
0/
/o
97.9- 99.8
99.1
99.4
Percent Solids
10
0/
/o
38-61
48.1
46.5
Mercury
10
mg/kg
0.018-440
56.3
0.36
Hexachlorobenzene
3
mg/kg
0,012-0.62
0.36
0.46
DDTR
3
mg/kg
<0.004 -4.3
1.44
0.012
3 of 5
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Record of Decision
Olin Mcintosh OU-2 Site
Table 5. Sediment Core Analytical Results - Coarse Cores (continued)
Number 2009
Depth of Range of Mean Median
Interval Analyte Samples Units2 Concentrations Concentration Concentration
Grain Size
Gravel 8 % 0-0 0 0
Sand 8 % 0.1-6.4 1.8 0.4
Silt/Clay/Colloids 8 0/o 93 q - 99.9 98.2 99.6
Percent Solids 8 % 43 -66 53.9 53.5
Mercury
8
mg/kg
0.06-120
16.2
0.15
Hexachlorobenzene
4
mg/kg
0.004- 0.51
0.14
0.022
DDTR 2 mg/kg <0.012-2.47 NA NA
Number 2009
Depth of Range of Mean Median
Interval Analyte Samples Units2 Concentrations Concentration Concentration
Grain Size
Gravel 7 % 0-0 0 0
Sand 7 % 0.2 - 4 0.9 0.4
Silt/Clay/Colloids 7 0/o 96.99.8 99.1 99.6
Percent Solids
7
0/
/O
43-64
53
54
Mercury
7
mg/kg
0.06-120
17.4
0.07
Hexachlorobenzene
4
mg/kg
0.011 - 0.29
0.104
0.12
DDTR
2
mg/kg
0.012-3.25
NA
NA
4 of 5
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Record of Decision
Olin Mcintosh OU-2 Site
Table 5. Sediment Core Analytical Results - Coarse Cores (continued)
Number
2009
Depth
of
Range of
Mean
Median
Interval
Analyte
Samples
Units2
Concentrations
Concentration
Concentration
Grain Size
Gravel
5
%
0-0
0
0
Sand
5
0/
/o
0.1 - 1.2
0.7
0.7
Silt/Clay/Colloids
5
0/
/o
98.8- 99.9
99.3
99.3
00
1
CD
Percent Solids
5
0/
/o
48-59
52.6
51
Mercury
5
mg/kg
0.06 - 230
46.2
0.11
Hexachlorobenzene 3 mg/kg ND ND ND
DDTR
mg/kg
0.001 - 34.2
NA
NA
Number
2009
Depth
of
Range of
Mean
Median
Interval
Analyte
Samples
Units2
Concentrations
Concentration
Concentration
Grain Size
Gravel
7
%
0-0
0
0
Sand
7
0/
/o
0.2-10.7
0.3
3.7
Silt/Clay/Colloids
7
0/
/o
89.3- 99.8
99.7
96.3
9- 10ft
Percent Solids
7
0/
/o
51-64
58
59
Mercury
3
mg/kg
0.055- 170
56.7
0.14
Hexachlorobenzene
mg/kg
ND
ND
ND
DDTR 2 mg/kg 0.01 - 3.24 NA NA
Number 2009
Depth of Range of Mean Median
Interval Analyte Samples Units2 Concentrations Concentration Concentration
Grain Size
Gravel 1
0/
/o
0-0
NA
NA
Sand 1
0/
/o
0.3
NA
NA
Silt/Clay/Colloids j
0/
/o
99.7
NA
NA
Percent Solids 1
0/
/o
51
NA
NA
Mercury 1
mg/kg
63
NA
NA
Hexachlorobenzene
Not Analyzed
DDTR 1
mg/kg
1.02
NA
NA
5 of 5
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Record of Decision
Olin Mcintosh OU-2 Site
Table 6. Sediment and Pore Water Core Analytical Results - Fine Cores
A. Fine Core Pore Water Results
Number
2009
Depth
of
Range of
Mean
Median
Interval
Analyte
Samples
Units
Concentrations
Concentration
Concentration
Mercury
6
ug/L
0.025 -23.3
5.68
0.106
0 - 2 in
Methyl
Mercury
6
ug/L
0.00064 - 0.0067
0.00239
0.001
0 - 4 in
Dissolved
Organic Carbon
6
mg/L
31 - 120
57
48
Number
2009
Depth
of
Range of
Mean
Median
Interval
Analyte
Samples
Units2
Concentrations
Concentration
Concentration
Mercury
6
ug/L
0.0137-4.7
1.01
0.183
2 - 4 in
Methyl
Mercury
6
ug/L
0.00064 - 0.0067
0.0014
0.00072
Number
2009
Depth
of
Range of
Mean
Median
Interval
Analyte
Samples
Units2
Concentrations
Concentration
Concentration
Mercury
6
ug/L
0.017 - 1.93
0.6
0.13
4 - 8 in
Methyl
Mercury
6
ug/L
0.00018 -0.0049
0.0019
0.00083
Dissolved
Organic Carbon
6
mg/L
20-150
53
33.5
Number
2009
Depth
of
Range of
Mean
Median
Interval
Analyte
Samples
Units2
Concentrations
Concentration
Concentration
Mercury
6
ug/L
0.010-0.74
2.18
0.49
8 - 12 in
Methyl
Mercury
6
ug/L
0.00096 -0.0041
0.0024
0.0023
8 -18 in
Dissolved
Organic Carbon
6
mg/L
19-85
48.8
45
Number
2009
Depth
of
Range of
Mean
Median
Interval
Analyte
Samples
Units2
Concentrations
Concentration
Concentration
Mercury
6
ug/L
0.089 - 10.3
0.36
0.34
12- 18 in
Methyl
Mercury
6
ug/L
0.00012 -0.0041
0.0018
0.0011
1 of 2
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Record of Decision
Olin Mcintosh OU-2 Site
Table 6. Sediment and Pore Water Core Analytical Results - Fine Cores (continued)
B. Fine Core Sediment Results
Depth
Interval
Analyte
Number
of
Samples
Units2
2009
Range of
Concentrations
Mean
Concentration
Median
Concentration
Mercury
6
mg/kg
2.5-46.7
24.5
26.5
0 - 2 in
Methyl Mercury
6
mg/kg
0.0014 -0.0067
0.0042
0.0041
Total Organic
Carbon
6
mg/kg
3300 -38000
20000
18500
Depth
Interval
Analyte
Number
of
Samples
Units2
2009
Range of
Concentrations
Mean
Concentration
Median
Concentration
Mercury
6
mg/kg
7.7 - 128
54.8
33
2 - 4 in
Methyl Mercury
6
mg/kg
0.0012 -0.0071
0.0046
0.005
Total Organic
Carbon
6
mg/kg
1600 - 34000
16655
17500
Depth
Interval
Analyte
Number
of
Samples
Units2
2009
Range of
Concentrations
Mean
Concentration
Median
Concentration
Mercury
6
mg/kg
0.41-96.6
34.3
27
4 - 8 in
Methyl Mercury
6
mg/kg
0.0019-0.0167
0.0072
0.0045
Total Organic
Carbon
6
mg/kg
5100 -33000
16500
15500
Depth
Interval
Analyte
Number
of
Samples
Units2
2009
Range of
Concentrations
Mean
Concentration
Median
Concentration
Mercury
6
mg/kg
18-200
62.6
33.3
8 - 12 in
Methyl Mercury
6
mg/kg
0.0031 -0.014
0.008
0.007
Total Organic
Carbon
6
mg/kg
3100 -27000
13920
15000
Depth
Interval
Analyte
Number
of
Samples
Units2
2009
Range of
Concentrations
Mean
Concentration
Median
Concentration
Mercury
6
mg/kg
0.37-46
15.7
15
8 - 12 in
Methyl Mercury
6
mg/kg
0.00022 - 0.0045
0.0021
0.0021
Total Organic
Carbon
6
mg/kg
1320 -21000
12470
15500
2 of 2
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Record of Decision
Olin Mcintosh OU-2 Site
Table 7. Surface Water Analytical Results (years 2006, 2008, and 2009)
Transect 1
Deep Samples
Shallow Samples
Sample ID:
Sample Date:
Sample Depth (ft.):
OU2B-SW-101DD-06
05/22/2006
8
OU2B-SW-101DD-08
06/04/2008
9
OU2B-SW-101DD-09
06/04/2009
13
OU2B-SW-101DS-06
05/22/2006
2
OU2B-SW -101DS-08
06/04/2008
2
OU2B-SW-101DS-09
06/04/2009
3.5
Depth to Bottom (ft.):
10
11.3
16.6
10
11.3
16.6
FIXED BASELABORATORY ANALYSIS:
Alkalinity - EPA 310.1, SM 2320B, mg/L
39
53.5
31.8
39
53.5
31.8
Dissolved Organic Carbon - SM 5310B, SW846 9060, mg/L
13
8.7
16
10
8.9
16
Hardness, Total - EPA 130.2, SM 2340C, mg/L
64
72
36
60
74
36
Mercurv - SW846 7470. EPA 1631. ue/L1
Mercury, Filtered
Mercury, Unfiltered
<0.2
<0.2
0.0121
0.292
0.0142
0.0547
<0.2
<0.2
0.014
0.137
0.00457
0.0106
Methvlmercurv - EPA 1630. ue/L
Methylmercury, Filtered
Methylmercury, Unfiltered
0.000396
0.000487
0.000883
0.00301
0.00048
0.000693
0.000244
0.000435
0.000867
0.00308
0.000461
0.000782
Sulfate, Total - SW846 9038, mg/L
35.1
NA
NA
29.9
NA
NA
Sulfide, Total - SW846 9030A, mg/L
<1
NA
NA
4.4
NA
NA
Total Dissolved Solids - EPA 160.1, SM 2540C, mg/L
140
420
55
136
410
57.5
Total Suspended Solids - EPA 160.2, SM 2540D, mg/L
7
7
<4
12
12
4.5
EM ,D PARAMETERS:
Dissolved Oxygen - EPA 360.1, mg/L
4.25
1.78
1.86
9.64
11.1
5.3
Oxidation Reduction Potential - A2580A, mV
215
33.4
304
204
-19.1
292
pH- EPA 150.1, pH Units
6.78
7.46
6.35
7.29
8.06
6.72
Specific Conductance - EPA 120.1, mS/cm
2.95
0.668
0.129
2.67
0.655
0.123
Temperature - EPA 170.1, °C
21.9
27.0
22.9
25.0
29.9
24.4
Turbidity - EPA 180.1, NTU
17.8
4.3
11.8
14.4
8.8
6.8
Notes:
°C- degrees Celsius
EPA - Environmental Protection Agency
J - estimated concentration based on data quality evaluation or result between rrethod detection limit and reporting detection limit
mg/L - milligram per liter
mS/cm - milliSienens per centirreter
mV - millivolt
NA - not analyzed
NTU - nephelometric turbidity unit
SM - Standard Methods
Hg/L - microgramperliter
< - result less than the reporting limit
1 Mercury analyzed by 7471 in 2006 and EPA 1631 in 2008.
1 of 5
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Record of Decision
Olin Mcintosh OU-2 Site
Table 7. Surface Water Analytical Results (years 2006, 2008, and 2009) (continued)
Transect 1
Transect 2
Deep Sample
Shallow Samples
Deep Sample
Shallow Samples
Sample ID:
Sample Date:
Sample Depth (ft.):
OU2B- S W -105DD
06/03/2008
r
4
-08 OU2B-S W - 105DD-09
06/08/2009
4.8
OU2B-SW-105DS
05/23/2006
2
-06 OU2B-SW-105DS-08
06/03/2008
r j
OU2B-SW-105DS-09
06/08/2009
1.2
OU2B-SW-201DD-08 OU2B-SW-201DD-09
06/04/2008 06/03/2009
4 8.8
OU2B-SW -201DS-06
05/22/2006
2
OU2B-SW-201DS-08
06/04/2008
r j
OU2B-SW -201DS-09
06/04/2009
2.2
Depth to Bottom (ft.):
5.8
6.17
3.15
5.8
6.17
5.7 11.3
3
5.7
11.3
FIXED BASELABORATORY ANALYSIS:
Alkalinity - EPA 310.1, SM 2320B, mg/L
53.5
31.8
39
58
31.8
55.8 31.8
39
53.5
31.8
Dissolved Organic Carbon - SM 5310B, SW846 9060, mg/L
16
17
2.9
16
17
16 16
<2
17
16
Hardness, Total - EPA 130.2, SM 2340C, mg/L
76
38
58
70
36
80 44
60
70
46
Mercurv - SW846 7470. EPA 1631. ug/L1
Mercury, Filtered
Mercury, Unfiltered
0.0121
0.0918
0.0129
0.155
<0.2
<0.2
0.0124
0.0914
0.0116
0.0879
0.019 0.0127
0.275 0.0957
<0.2
<0.2
0.0143
0.18
0.0053
0.0087
Methvlmercurv - EPA 1630. ue/L
Methylmercury, Filtered
Methylmercury, Unfiltered
0.000679
0.00245
0.000649
0.00171
0.000227
0.000508
0.000960
0.00228
0.000419
0.00119
0.000858 0.000468
0.00316 0.000756
0.000261
0.000480
0.000843
0.00257
0.000422
0.000748
Sulfate, Total - SW846 9038, mg/L
NA
NA
33.2
NA
NA
NA NA
30.3
NA
NA
Sulfide, Total - SW846 9030A, mg/L
NA
NA
<1
NA
NA
NA NA
2.6
NA
NA
Total Dissolved Solids - EPA 160.1, SM 2540C, mg/L
420
72.5
140
400
72.5
385 82.5
136
405
65
Total Suspended Solids - EPA 160.2, SM 2540D, mg/L
12
22
15
12
16
<4 4.5
6
7
6.5
FIELD PARAMETERS:
Dissolved Oxygen - EPA 360.1, mg/L
7.16
7.20
5.7
11.2
9.31
7.47 3.17
9.7
8.99
9.36
Oxidation Reduction Potential - A2580A, mV
-17.1
264
165
-52.1
257
405 277
192
372
263
pH - EPA 150.1, pHUnits
8.58
6.72
8.41
8.7
6.92
6.96 6.53
7.35
7.21
6.96
Specific Conductance - EPA 120.1, mS/cm
0.635
0.143
3.71
0.631
0.144
0.742 0.117
2.66
0.747
0.121
Temperature - EPA 170.1, °C
28.7
24.6
27.0
31.9
25.9
27.7 23.1
24.6
28.2
26.4
Turbidity - EPA 180.1, NTU
18.8
26.7
13.8
9.3
9.8
<0.1 10.8
20.5
<0.1
8.4
Notes;
°C- degrees Celsius
EPA - Environmental Protection Agency
J - estimated concentration based on data quality evaluation or result between method detection limit and reporting detection limit
mg/L - milligram per liter
mS/cm- milliSiemens per centimeter
mV - millivolt
NA - not analyzed
NTU - nephelometric turbidity unit
SM - Standard Methods
jig/L - microgram per liter
< - result less than the reporting limit
1 Mercury analyzed by 7471 in 2006 and EPA 1631 in 2008.
2 of 5
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Record of Decision
Olin Mcintosh OU-2 Site
Table 7. Surface Water Analytical Results (years 2006, 2008, and 2009) (continued)
Transect 2
Transect 2
Deep Samples
Shallow Samples
Deep Sample
Shallow Samples
Sample ID:
Sample Date:
Sample Depth (ft.):
OU2B- S W -203DD-06
05/22/2006
r
5
OU2B-SW-203DD-08
06/04/2008
r
OU2B-SW -203DD-09
06/04/2009
12
OU2B-SW-203DS-06
05/22/2006
»
1
OU2B-SW-203DS-08
06/04/2008
2
OU2B-SW -203DS-09
06/04/2009
3
OU2B-SW-205DD-08
06/03/2008
r
4
OU2B-SW-205DD-09
06/08/2009
4
OU2B-SW-205DS-06
05/22/2006
r
1
OU2B-SW -205DS-08
06/03/2008
F ^
OU2B-SW-205DS-09
06/03/2009
1
Depth to Bottom (ft.):
6.15
9.5
14.7
6.15
9.5
14.7
4.9
5.83
1.5
4.9
5.83
FIXED BASELABORATORY ANALYSIS:
Alkalinity - EPA 310.1, SM 2320B, mg/L
35.9
53.5
31.8
42.1
53.5
31.8
53.5
31.8
37.4
55.8
33.9
Dissolved Organic Carbon - SM 5310B, SW846 9060, mg/L
4.8
16
16
3.4
16
16
18
17
<2
16
17
Hardness, Total - EPA 130.2, SM 2340C, mg/L
58
80
34
60
78
34
70
36
56
76
34
Mercurv - SW846 7470. EPA 1631. us/L1
Mercury, Filtered
Mercuiy, Unfiltered
<0.2
<0.2
0.0158
0.308
0.0147
0.0925
<0.2
<0.2
0.0227
0.36
0.00458
0.0119
0.0111
0.319
0.00824
0.0623
<0.2
<0.2
0.0123
0.0942
0.0116 J
0.0563
Methvlmercurv - EPA 1630. us/L
Methylmercuiy, Filtered
Methylmercuiy, Unfiltered
0.000249
0.000416
0.000625
0.00238
0.000506
0.000702
0.000249
0.000429
0.000606
0.00271
0.000468
0.000767
0.000609
0.00310
0.000413
0.00106
0.000148
0.000399
0.000673
0.00236
0.000468
0.00087
Sulfate, Total - SW846 9038, mg/L
31.1
NA
NA
29.1
NA
NA
NA
NA
29.9
NA
NA
Sulfide, Total - SW846 9030A, mg/L
<1
NA
NA
3.5
NA
NA
NA
NA
<1
NA
NA
Total Dissolved Solids - EPA 160.1, SM 2540C, mg/L
136
400
72.5
144
410
45
400
70
136
400
55 J
Total Suspended Solids - EPA 160.2, SM 2540D, mg/L
9
7
<4
7
8
4
19
15
14
8
10 J
FTETD PARAMETERS:
Dissolved Oxygen - EPA 360.1, mg/L
4.64
0.78
2.25
8.09
6.62
9.98
8.94
9.16
10.59
12.9
10.32
Oxidation Reduction Potential - A2580A, mV
197
47.4
251
191
46.5
197
381
287
195
328
282
pH-EPA 150.1, pH Units
7.13
6.69
6.44
7.15
6.78
7.20
7.37
7.04
7.51
8.74
7.24
Specific Conductance - EPA 120.1, mS/cm
2.67
0.622
0.127
2.61
0.613
0.125
0.760
0.141
2.80
0.758
0.145
Temperature -EPA 170.1, °C
23.2
27.2
22.9
25.1
29.3
25.6
28.0
25.2
26.7
30.6
27.1
Turbidity-EPA 180.1,NTU
18.9
6.8
13.5
12.8
11.7
5.4
18.8
26.8
17.5
8.9
7.5
Notes;
°C- degrees Celsius
EPA - Environmental Protection Agency
J - estimated concentration based on data quality evaluation or result between method detection limit and reporting detection limit
mg/L - milligram per liter
mS/cm - milliSiemens per centimeter
mV-millivolt
NA - not analyzed
NTU - nephelometric turbidity unit
SM - Standard Methods
jig/L - microgram per liter
< - result less than the reporting limit
1 Mercuiy analyzed by 7471 in 2006 and EPA 1631 in 2008.
3 of 5
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Record of Decision
Olin Mcintosh OU-2 Site
Table 7. Surface Water Analytical Results (years 2006, 2008, and 2009) (continued)
Transect 3
Transect 3
Deep Sample
Shallow Samples
Deep Sample
Shallow Samples
Sample ID:
Sample Date:
Sample Depth (ft.):
OU2B-SW -301DD-08 OU2B-SW-301DD-09
06/03/2008 06/03/2009
r
3.2 8
OU2B-S W -301DS-06
05/23/2006
1
OU2B-SW-301DS-08
06/03/2008
IT
0.8
OU2B-SW -301DS-09
06/03/2009
2
OU2B-SW -303DD-08
06/03/2008
r
4
OU2B-S W-303DD-09
06/03/2009
8
OU2B-SW-303DS-06
05/22/2006
r
2
OU2B-SW -303DS-08
06/03/2008
r j
OU2B-S W -303DS-09
06/03/2009
2
Depth to Bottom (ft.):
4.3 10.2
1.4
4.3
10.2
5.7
10.8
3.03
5.7
10.8
FIXED BASE LABORATORY ANALYSIS:
Alkalinity - EPA 310.1, SM 2320B, ng/L
53.5
31.8
37.4
53.5
31.8
53.5
31.8
40.6
53.5
31.8
Dissolved Organic Carbon - SM 5310B, SW846 9060, mg/L
17
16
2.5
16
16
15
16
6.8
16
16
Hardness, Total - EPA 130.2, SM 2340C, mg/L
72
50
61
72
40
68
44
58
72
40
Mercurv - SW846 7470. EPA 1631. us/L1
Mercury, Filtered
Mercury, Unfiltered
0.0209
0.471
0.00444
0.0142
<0.2
0.329
0.0146
0.181
0.00358
0.00961
0.0249
0.909
0.00693
0.0608
<0.2
<0.2
0.0138
0.131 J
0.00405
0.0114
Methvlmercurv - EPA 1630. ue/L
Methylmercury, Filtered
Methylmercury, Unfiltered
0.000952
0.00403
0.00046
0.000714
0.000295
0.000970
0.000643
0.00311
0.00042
0.000786
0.000731
0.00345
0.000476
0.000652
0.000214
0.000354
0.000893
0.00191
0.000413
0.000918
Sulfate, Total - SW846 9038, mg/L
NA
NA
30.6
NA
NA
NA
NA
29.4
NA
NA
Sulfide, Total - SW846 9030A, mg/L
NA
NA
<1
NA
NA
NA
NA
<1
NA
NA
Total Dissolved Solids - EPA 160.1, SM 2540C, mg/L
384
87.5
160
392
72.5
404
105
124
404
87.5
Total Suspended Solids - EPA 160.2, SM 2540D, ng/L
13
4.5
48
15
5
23
<4 UJ
8
12 J
7
FT1T T) PARAMETERS:
Dissolved Oxygen - EPA 360.1, mg/L
9.71
3.11
NA
11.66
8.93
7.82
3.29
8.48
12.73
7.71
Oxidation Reduction Potential - A2580A, mV
427
259
198
401
236
380
277
205
326
262
pH- EPA 150.1, pHUnits
7.03
6.45
6.99
7.57
6.68
7.61
6.47
7.66
8.81
6.86
Specific Conductance - EPA 120.1, mS/cm
0.738
0.116
NA
0.744
0.122
0.756
0.117
2.62
0.754
0.120
Temperature - EPA 170.1, °C
28.0
23.2
26.1
28.8
26.2
27.6
23.2
26.1
29.9
25.9
Turbidity - EPA 180.1, NTU
11.9
10.5
32.3
7.3
8.6
23.8
11.5
17.8
5.5
9.0
Notes;
°C - degrees Celsius
EPA - Environmental Protection Agency
J - estimated concentration based on data quality evaluation or result between method detection limit and reporting detection limit
mg/L - milligram per liter
mS/cm- milliSiemens per centimeter
mV - millivolt
NA - not analyzed
NTU - nephelometric turbidity unit
SM - Standard Methods
jug/L - microgram per liter
< - result less than the reporting limit
1 Mercury analyzed by 7471 in 2006 and EPA 1631 in 2008.
4 of 5
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Record of Decision
Olin Mcintosh OU-2 Site
Table 7. Surface Water Analytical Results (years 2006, 2008, and 2009) (continued)
Trans ect3
Round Pond
Deep
Hole
Deep Sample
Shallow Sample
Deep Sample
Shallow Samples
Deep Samples
Shallow Samples
Sample ID:
Sample Date:
Sample Depth (ft.):
OU2B-SW -304DD-08
06/03/2008
4
OU2B-SW -304DD-09
06/03/2009
8
OU2B-SW -304DS-06
05/22/2006
2
OU2B-SW-304DS-08
06/03/2008
1
OU2B-SW -304DS-09
06/03/2009
8
OU2R-SW-101DD-08
06/03/2008
4.5
OU2R-SW-101DD-09
06/04/2009
8.8
OU2R-SW-101DS-06
05/23/2006
2
OU2R-SW-101DS-08
06/03/2008
1
OU2R-SW-101DS-09
06/04/2009
2.2
OU2B-SW-DHDD-09
06/04/2009
36
OU2B-SW-DHDS-09
06/04/2009
9
Depth to Bottom (ft.):
5.6
10.4
3.2
5.6
10.4
6.1
10.8
2.5
6.1
10.8
44.1
44.1
FIXED BASELABORATORY ANALYSIS:
Alkalinity - EPA 310.1, SM 2320B, mg/L
53.5
31.8
40.6
53.5
31.8
55.8
31.8
39
55.8
31.8
44.5
31.8
Dissolved Organic Carbon - SM 5310B, SW846 9060, mg/L
15
16
4.2
16
16
18
16
5.4
18
15
18
16
Hardness, Total - EPA 130.2, SM 2340C, mg/L
78
46
60
66
46
80
48
61
80
46
52
40
Mercurv - SW846 7470. EPA 1631. ue/L1
Mercuiy, Filtered
Mercuiy, Unfiltered
0.0141
0.335
0.00579
0.0223 J
<0.2
0.2
0.0114
0.0838
0.00416
0.0121
0.0109
0.0834
0.00463
0.0139
<0.2
<0.2
0.00858
0.0443
0.00357
0.00731
0.0117
0.110
0.00588
0.0347
Methvlmercurv - EPA 1630. ue/L
Methylmercuiy, Filtered
Methylmercuiy, Unfiltered
0.000586
0.00269
0.000491
0.000833
0.000204
0.000550
0.000883
0.00238
0.000476
0.000791
0.00342
0.00553
0.000556
0.000788
0.000108
0.000239
0.00225
0.00484
0.000532
0.000825
0.000638
0.00108
0.00047
0.000735
Sulfate, Total - SW846 9038, mg/L
NA
NA
30
NA
NA
NA
NA
28.9
NA
NA
NA
NA
Sulfide, Total - SW846 9030A, mg/L
NA
NA
<1
NA
NA
NA
NA
<1
NA
NA
NA
NA
Total Dissolved Solids - EPA 160.1, SM 2540C, mg/L
435
115
140
360
97.5
280
125
120
328
112
62.5
52.5
Total Suspended Solids - EPA 160.2, SM 2540D, ng/L
20
6.5
24
7
12
8
9.5
16
18
<4
8
4
FIELD PARAMETERS:
Dissolved Oygen - EPA 360.1, mg/L
9.68
2.93
NA
NA
10.44
2.85
2.16
5.1
7.78
9.5
0.16
2.45
Oxidation Reduction Potential - A2580A, mV
386
239
196
385
200
38.7
286
176
41.6
268
72.8
248
pH - EPA 150. l,pH Units
7.54
6.53
7.29
8.39
7.14
7.12
6.50
6.96
7.38
7.01
6.40
6.41
Specific Conductance - EPA 120.1, mS/cm
0.756
0.116
NA
0.763
0.122
0.453
0.119
2.40
0.493
0.120
0.188
0.126
Temperature - EPA 170.1, °C
28.5
23.4
25.5
29.9
26.9
26.8
23.1
25.8
28.5
26.4
20.9
23.2
Turbidity-EPA 180.1,NTU
15.2
11.5
30.6
4.8
9.3
12.8
15.8
74.1
4.0
9.2
26.6
9.0
Notes:
°C - degrees Celsius
EPA - Environmental Protection Agency
J - estimated concentration based on data quality evaluation or result between method detection limit and reporting detection limit
mg/L - milligram per liter
mS/cm-milliSiemens per centimeter
mV - millivolt
NA - not analyzed
NTU - nephelometric turbidity unit
SM - Standard Methods
jig/L -microgramperliter
< - result less than the reporting limit
1 Mercuiy analyzed by 7471 in 2006 and EPA 1631 in 2008.
5 of 5
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Record of Decision
Olin Mcintosh OU-2 Site
Table 8. Vegetation Analytical Results (2010)
Location ID: FPV-SB1
FPV-SB3
FPV-SB4
FPV-SB5
FPV-SS1
FPV-SS1
FPV-SS4
FPV-SS10
FPV-SS11
FPV-SS11
FPV-SS12
FPV-SS14
Sample ID: OU2B-FPVSB1-10
OU2B-FP VSB3-10
OU2B-FP VSB4-10
OU2B-FPVSB5-10
OU2B-FPVSS1-10
OU2B-FPVSSDUP01-10
OU2B-FPVSS4-10
OU2B-FPVSS10-10
OU2B-FPVSS11-10
OU2B-FP VSSDUP02-10
OU 2B-FP VS S12-10
OU2B-FPVSS14-10
Sample Date: 7/7/2010
7/8/2010
7/8/2010
7/7/2010
7/7/2010
7/7/2010
7/7/2010
7/8/2010
7/7/2010
7/7/2010
7/7/2010
7/7/2010
Sample Type: Normal
Normal
Normal
Normal
Normal
Duplicate
Normal
Normal
Normal
Duplicate
Normal
Normal
Mercurv. EPA 245.6. mg/Kg
Mercury
<0.017
<0.017
<0.017
<0.017
<0.017
<0.017
<0.017
<0.017
<0.017
NA
<0.017
<0.017
Methvlmercurv. EPA 1630. mg/Kg
Methylmercury
0.000829 JQ
0.000704 JQ
0.000656 JQ
0.0147
0.00139 J
0.000643 JQ
0.000903 JQ
0.000927 JQ
0.00112
0.000748 JQ
0.000751 JQ
0.00226
Percent Iinids.%
Percent Lipids
" 0.24
" 0.32
0.15
0.19
0.40
r Q40 it
0.13
0.38 J
" 0.13
f ft20 f
0.20
" 0.18
Pesticides - SW846 8081. mg/Kg
2,4-DDD
NA
<.0025
<0.0025
NA
0.0011 JQ
<0.0025
<0.0025
NA
NA
NA
NA
NA
2,4-DDE
NA
0.00082 JQ
<0.0025
NA
<0.0025
<0.0025
<0.0025
NA
NA
NA
NA
NA
2,4-DDT
NA
<0.0025
<0.0025
NA
0.0034 J
<0.0025 UJ
<0.0025
NA
NA
NA
NA
NA
4,4-DDD
NA
<0.0050
<0.0050
NA
<0.0050
<0.0050
0.0049 JQ
NA
NA
NA
NA
NA
4,4-DDE
NA
<0.0050
<0.0050
NA
<0.0050
<0.0050
<0.0050
NA
NA
NA
NA
NA
4,4-DDT
NA
<0.0050
<0.0050
NA
<0.0050
<0.0050
<0.0050
NA
NA
NA
NA
NA
DDTr
NA
0.00082
<0.0050
NA
<0.0050
<0.0050
0.0049
NA
NA
NA
NA
NA
DDTR
NA
0.00082
<0.0050
NA
0.0045
<0.0050
0.0049
NA
NA
NA
NA
NA
Heachlorobenzene
<.0025
NA
NA
<0.0025
NA
NA
NA
<0.0025
<0.0025
<0.0025 UJ
0.00060 JQ
0.0048 J
Notes:
DDTr = 4,4-DDD, -DDE, and -DDT
DDTR=2,4'- and 4,4-DDD, -DDE, -DDT
SW846 = Test Methods for Evaluating Solid Waste,
Physical/Chemical Methods
mg/Kg = milligrams per kilogram diy weight
When calculating DDTr and DDTR, a value of zero was used for results below
the Method Detection Limit (MDL) and/or the Reporting Limit (RL).
Data flag Definitions:
J=Estimated concentration based on qc data
JQ=Estimated concentration, result reported is between
the Method Detection Limit (MDL) and the Reporting Limit (RL)
UJ=The analyte was not detected; however, the result is estimated due to
discrepancies in meeting certain analyte-specific quality control criteria
NA=Not Analyzed
<=Result is less than the Reporting Limit
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 9. 2010 Spider and Insect Analytical Results
Location ID: INS-IB
INS-2C
INS-3B
INS-4B
INS-C
INS-5B
INS-5C
INS-6A
INS-6B
INS-6C
INS-NEA
INS-NEC
INS-SEA
Sample ID: OU2B-INS1B-10
OU2B-INS2C-10
OU2B-INS3B-10
OU2B-INS4B-10
OU2B-INS4C-10
OU2B-INS5B-10
OU2B-INS5C-10
OU2B-INS6A-10
OU2B-INS6B-10
OU2B-INS6C-10
OU2B-INSNEA-10
OU2B-INSNEC-10
OU2B-INSSEA-10
Sample Date: 7/12/2010
7/12/2010
7/12/2010
7/9/2010
7/12/2010
7/13/2010
7/13/2010
7/9/2010
7/9/2010
7/9/2010
7/12/2010
7/12/2010
7/12/2010
Sample Type: Normal
Normal
Normal
Normal
Normal
Normal
Normal
Normal
Normal
Normal
Normal
Normal
Normal
Mercurv. IPA 245.6. ms/Ks
w
0.32
if
0.37
IF
0.31
w
0.14
w
0.067
F
0.71
w
0.17
w
0.075
IF
0.13
Mercury
0.26
0.0075 JQ
0.15 J
IF
0.026
Percent Lirads. %
r
4.0
if"
4.0
r
3.9
4.4
Percent Lipids
3.2
3.3
4.1
2.8
3.3
3.3
3.6
3.5
3.6
Pesticides - SW846 8081. ms/Ks
2,4'-DDD
0.0054
0.0052
0.006
0.0044
<0.0050
0.0045
<0.0038
0.0026 JQ
0.0020 JQ
<0.0032
0.0019 JQ
0.0035 JQ
0.0013 JQ
2,4'-DDE
0.0168 J
0.0138 J
0.0292
0.0225
0.0041 JQ
0.0226 J
<0.0038
0.0095
<0.0061
<0.0032
0.0064
0.0054 J
0.0077
2,4'-DDT
0.00068 JQ
<0.0025
0.00072 JQ
0.00070 JQ
<0.0050
0.00091 JQ
<0.0038
0.0028 JQ
<0.0061
<0.0032
0.0010 JQ
<0.0046
<0.0025
4,4'-DDD
0.014
0.0113
0.01
0.0121
<0.0099
0.0033 JQ
0.0022 JQ
<0.0122
<0.0122
<0.0065
0.0206
0.0052 JQ
0.0057 J
4,4'-DDE
0.606
0.318
0.288
0.233
<0.0099
0.0866 J
0.0053 JQ
0.175
0.0337
0.0042 JQ
0.301
0.0307
0.121
4,4'-DDT
0.0166
0.0040 JQ
0.0033 JQ
0.0094
<0.0099
0.0024 JQ
0.0020 JQ
0.0078 JQ
0.0022 JQ
<0.0065
0.0040 JQ
0.0015 JQ
0.0052
DDTr1
0.64
0.33
0.30
0.25
<0.0099
0.092 J, JQ
0.0095 JQ
0.18 JQ
0.036 JQ
0.0042 JQ
0.33 JQ
0.037 JQ
0.13 J
DDTr2
0.64
0.33
0.30
0.25
<0.0099
0.092 J, JQ
0.0095 JQ
0.20 JQ
0.042 JQ
0.011 JQ
0.33 JQ
0.037 JQ
0.13 J
DDTR1
0.66 J, JQ
0.35 J, JQ
0.34 JQ
0.29
0.0041 JQ
0.12 J, JQ
0.0095 JQ
0.20 JQ
0.038 JQ
0.0042 JQ
0.33 JQ
0.046 J, JQ
0.14 J, JQ
DDTR2
0.66 J, JQ
0.35 J, JQ
0.34 JQ
0.29
0.024 JQ
0.12 J, JQ
0.015 JQ
0.21 JQ
0.050 JQ
0.016 JQ
0.33 JQ
0.049 J, JQ
0.14 J, JQ
Hexachlorobenzene
0.0018 JQ
0.0088
0.0029 J
0.017
0.0025 JQ
0.0133
0.015
0.0157
0.039
0.035
0.0023 JQ
0.0099
0.0010 JQ
Notes:
DDTr = 4,4'-DDD, -DDE, and -DDT
DDTR=2,4'- and 4,4'-DDD, -DDE, -DDT
SW846 = Test Methods for Evaluating Solid Waste,
Physical/Chemical Methods
mg/Kg = milligrams per kilogram dry weight
'When calculating DDTr and DDTR, a value ofzerowas used for results below
the Method Detection Limit (MDL) and/or the Reporting Limit (RL).
2 When calculating DDTr and DDTR, a value of half the detection limit was
us ed for results below the method detection limit and/or the reporting limit.
Data Hag Definitions:
J=Estimated concentration based on qc data
JQ=Estimated concentration, result reported is between
the Method Detection Limit (MDL) and the Reporting Limit (RL)
< = Result is less than the Reporting Limit
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 10. Historical Fish Tissue Analytical Results (1986 - 2001)
Sample Type
Sample
Location
Constituent
Units2
1986
Range of Concentrations
1991
Range of Concentrations
1994
Range of Concentrations
1995
Range of Concentrations
2001
Range of Concentrations
Smallmouth Buffalo Filet
OU-2
Hg
mg/kg
0.59
Channel Catfish Whole
Body
OU-2
Hg
HCB
DDTr
mg/kg
mg/kg
mg/kg
--
<0.20-0.60
0.16JN- 1.8 JN
2.9-29.0
--
--
--
Channel Catfish Fillet
OU-2
Hg
HCB
DDTr
mg/kg
mg/kg
mg/kg
0.66-0.68
0.28-0.67
<0.66 -0.58 J N
1.1 -9.3
--
--
--
Mosquitofish1 Whole
OU-2
Hg
HCB
DDTR
DDTr
mg/kg
mg/kg
mg/kg
mg/kg
--
--
0.27 J-0.58 J
<0.027 -0.13
2.8-43.2
2.2-30.7
--
0.19-0.51
<0.10-0.14
0.49-10.8
Body
Tombigbee
River
Hg
HCB
DDTR
DDTr
mg/kg
mg/kg
mg/kg
mg/kg
--
--
0.04 J-0.14 J
<0.031
<0.01 -0.026
<0.01 -0.026
--
--
Rock Bass Fillet
OU-2
Hg
mg/kg
0.97
—
—
—
—
Bluegill Whole Body
OU-2
Hg
MeHg
mg/kg
mg/kg
--
--
--
0.69-1.2
0.57-1.2
--
Bluegill Filet
OU-2
Hg
mg/kg
0.78
—
—
—
—
Largemouth Bass Whole
OU-2
Hg
HCB
DDTR
DDTr
mg/kg
mg/kg
mg/kg
mg/kg
--
0.47 - 1.2
0.23 JN - 1.6
7.0-47
0.49 - 1.2
0.093 - 1.8
8.8 - 106
6.6-80.8
--
0.2 - 1.58
1.08 -31.793
Body
Lake
Hatchetigbee
(Reference)
Hg
HCB
DDTR
DDTr
mg/kg
mg/kg
mg/kg
mg/kg
--
--
0.13-0.36
<0.01
0.042 -0.36
0.042 -0.31
--
--
Largemouth Bass Fillet
OU-2
Hg
HCB
DDTr
mg/kg
mg/kg
mg/kg
0.12 - 1.9
0.9-2.2
<0.66-0.20 J N
1.4 - 10.0
--
--
0.30-2.3
<0.025 -0.18
<0.05-2.61
Notes:
1 Composite sample DDTr - the sum of the 4,4'- isomers of DDT, DDD, and DDE mg/kg - milligrams per kilogram
2 Sample basis as received DDTR - the sum of the 2,4'- and 4,4' - isomers of DDT, DDD, and DDE N - spiked sample recovery was not within detection limits
3 Whole body concentration estimated from fillet and offal data HCB - hexachlorobenzene ~ - sample not collected and/or sample not analyzed for specified constituent
DDD - dichlorodiphenyldichloroethane Hg - mercury < - less than the reporting limit
DDE - dichlorodiphenyldichloroethylene J - estimated result
DDT - dichlorodiphenyltrichloroethane MeHg - methylmercury
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 11. Recent Fish Tissue Analytical Results (2003 - 2010)
Sample
2003
2005
2006
2007
2008
2010
Sample Type
Location
Constituent
Units2
Range of Concentrations
Range of Concentrations
Range of Concentrations
Range of Concentrations
Range of Concentrations
Range of Concentrations
Longnose Gar
Whole Body
OU-2
Hg
mg/kg
--
1.7
--
--
--
--
Channel Catfish
Fillet
OU-2
Hg
mg/kg
0.10-0.51
--
--
--
--
--
Silversides1
Whole Body
OU-2
Hg
HCB
DDTR
mg/kg
mg/kg
mg/kg
--
--
--
--
0.60 - 1.2
0.087-2.0
0.40-0.51
0.040 - 0.096
0.88 - 1.82
Striped Bass
Whole Body
OU-2
Hg
mg/kg
--
0.38
--
--
--
--
Bluegill Whole
Body
OU-2
Hg
HCB
mg/kg
mg/kg
--
--
--
--
0.54-1.20
0.054-0.64
0.30-0.96
0.022-0.301
DDTR
mg/kg
--
--
--
--
--
0.56-5.46
Largemouth Bass
Whole Body
OU-2
Hg
HCB
DDTR
mg/kg
mg/kg
mg/kg
--
--
--
--
1.1-2.0
0.034 - 1.03
0.6 - 1.5
0.020 - 1.04
0.674 - 39.2
Largemouth Bass
Fillet
OU-2
Hg
HCB
mg/kg
mg/kg
0.30 - 1.3
1.0 - 1.5
1.5-2.2
1.6-3.0
0.036 -0.14
0.86-2.8
0.012-0.039
DDTR
mg/kg
--
--
--
--
--
0.095 -0.367
Notes:
1 Composite sample
2 Sample basis as received
HCB - hexachlorobenzene
Hg - mercury
mg/kg - milligrams per kilogram
— - sample not collected and/or sample not analyzed for specified constituent
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 12. Analytical Results for Other Biota
Sample Type
Sample Location
Constituent
Units (e)
1994
Range of Concentrations
1995
Range of Concentrations
2001
Range of Concentrations
Terrestrial Insects and
Spiders
OU-2
Hg
mg/kg
0.10-0.21
0.05 - 0.24
--
HCB
mg/kg
<0.014-0.45
--
--
Spiders
OU-2
Hg
mg/kg
--
0.24 (a)
--
Terrestrial Insects (f)
OU-2
Hg
mg/kg
<0.04-0.21
0.05 (b)
--
HCB
mg/kg
<0.013-0.45
--
--
DDTr
mg/kg
0.07-2.9
--
--
DDTR
mg/kg
0.08-5.3
--
--
Lake Hatchetigbee (Reference)
Hg
mg/kg
<0.03 - 0.04
--
--
HCB
mg/kg
<0.012-0.048
--
--
DDTr
mg/kg
<0.020
--
--
DDTR
mg/kg
<0.020
--
--
Aquatic Insects (f)
OU-2
Hg
mg/kg
0.20 - 0.24
0.25 (c)
0.033- 0.15
HCB
mg/kg
1.1-1.2
--
<0.25-3.1
DDTr
mg/kg
5.3-6.5
--
--
DDTR
mg/kg
11.7-14.1
--
4.19-27.3
Lake Hatchetigbee (Reference)
Hg
mg/kg
0.06
--
--
HCB
mg/kg
<0.016
--
--
DDTr
mg/kg
<0.020
--
--
DDTR
mg/kg
<0.020
--
--
Raccoon Whole Body (d)
(f)
OU-2
Hg
mg/kg
0.53 - 0.96
--
--
HCB
mg/kg
<0.01 -0.21
--
--
DDTr
mg/kg
0.055 - 0.556
--
--
DDTR
mg/kg
0.07 - 0.57
--
--
Lake Hatchetigbee (Reference)
Hg
mg/kg
0.14-0.29
--
--
HCB
mg/kg
<0.01
--
--
DDTr
mg/kg
<0.01
--
--
DDTR
mg/kg
<0.01
--
--
Raccoon Whole Hair (f)
OU-2
Hg
mg/kg
12-14
--
--
HCB
mg/kg
<0.0071 - 0.053
--
--
DDTr
mg/kg
0.028- 0.18
--
--
DDTR
mg/kg
0.038- 0.29
--
--
Lake Hatchetigbee (Reference)
Hg
mg/kg
0.93-3.0
--
--
HCB
mg/kg
<0.0076
--
--
DDTr
mg/kg
<0.0076
--
--
DDTR
mg/kg
<0.0076
—
—
1 of 2
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 12. Analytical Results for Other Biota (continued)
Sample Type
Sample Location
Constituent
Units (e)
1994
Range of Concentrations
1995
Range of Concentrations
2001
Range of Concentrations
Little Blue Heron Whole Body
(d)(1)
OU-2
Hg
mg/kg
0.30-1.7
--
--
HCB
mg/kg
<0.01 -0.41
--
--
DDTr
mg/kg
0.339-28.1
--
--
DDTR
mg/kg
0.35 - 32.8
--
--
Lake Hatchetigbee (Reference)
Hg
mg/kg
0.48-0.91
--
--
HCB
mg/kg
<0.01
--
--
DDTr
mg/kg
<0.01 -0.13
--
--
DDTR
mg/kg
<0.01 - 0.147
--
--
Little Blue Heron Feathers (g)
OU-2
Hg
mg/kg
0.60-7.7
--
--
HCB
mg/kg
<0.01 - 0.017
--
--
DDTr
mg/kg
<0.01 - 0.745
--
--
DDTR
mg/kg
<0.01 - 0.878
—
—
Lake Hatchetigbee (Reference)
Hg
mg/kg
CO
CO
1
CD
--
--
HCB
mg/kg
<0.01
--
--
DDTr
mg/kg
<0.05
--
--
DDTR
mg/kg
<0.05
--
--
Bull Frog (f)
OU-2
Hg
mg/kg
0.1 - 0.46
--
--
HCB
mg/kg
<0.01 - 0.057
--
--
DDTr
mg/kg
0.033-2.73
--
--
DDTR
mg/kg
0.048-2.795
--
--
Lake Hatchetigbee (Reference)
Hg
mg/kg
<0.04 - 0.06
--
--
HCB
mg/kg
<0.01
--
--
DDTr
mg/kg
<0.01
--
--
DDTR
mg/kg
<0.01
--
--
Crayfish (g)
OU-2
Hg
mg/kg
0.13-0.20
--
--
HCB
mg/kg
0.088- 0.91
--
--
DDTr
mg/kg
0
1
cn
--
--
DDTR
mg/kg
0.43-1.6
--
--
Lake Hatchetigbee (Reference)
Hg
mg/kg
<0.04 - 0.04
--
--
HCB
mg/kg
<0.008
--
--
DDTr
mg/kg
<0.008
--
--
DDTR
mg/kg
<0.008
--
--
Mussels (g)
OU-2
Hg
mg/kg
0.05 - 0.25
--
--
HCB
mg/kg
0.017-0.16
--
--
DDTr
mg/kg
0.522-2.297
--
--
DDTR
mg/kg
0.951 -4.52
--
--
Lake Hatchetigbee (Reference)
Hg
mg/kg
<0.04
--
--
HCB
mg/kg
<0.008
--
--
DDTr
mg/kg
<0.008
--
--
DDTR
mg/kg
<0.008
--
--
Notes: DDTr- the sum of the 4,4'- isomers of DDT, DDE, and DDD; DDTR-the sume of the 2,4'- and 4,4'- isomers of DDT, DDE, and DDD
(a) Samples (n=36) collected during prothonotary warbler study collected at the site. Concentration is the average concentration of the 36 samples.
(b) Samples (n=201) collected during prothonotary warbler study collected at the site. Concentration is the average concentration of the 201 samples.
(c) Samples (n=30) collected during prothonotary warbler study collected at the site. Concentration is the average concentration of the 30 samples.
(d) Contents of digestive systems were not removed prior to analysis
(e) Sample basis as received by the laboratory; (f) DDTr and DDTR were calculated
historically using one-half the detection limits where non-detect
(g) Obtained from database, which were calculated using 0 where non-detect
2 of 2
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 13. Vegetation and Land Cover Types
Updated Ecological Risk Assessment
Olin-Mcintosh
Operable Unit 2
Vegetation/Land Cover Type
Mcintosh, Alabama,
Acres
Percentage of Total
Mixed Upland Forest
1
1°0
Semi-Permanently Flooded Bottomland Forest
35
18°o
Temporarily Flooded Bottomland Forest
60
30%
Shrub Dominated Zone
4
2%
Herbaceous Dominated Zone
2
1%
Open Water Ponds and Streams
82
42%
Other (roads, etc,)
12
6%
Notes:
Vegetation survey conducted in September 1991.
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 14. Selection of Human Health Exposure Pathways
Scenario
Timeframe
Medium
Exposure
Medium
Exposure Point
Receptor
Population
Receptor
Age
Exposure
Route
On Site/ Off-
Site
Type of
Analysis
Rationale for Selection of Exclusion of Exposure Pathway
Current/
Future
Surface Soil
Floodplain Soil
Trespassing
(walking/
hiking) in OU-2
Floodplain
Trespasser
Adult
Ingestion
Onsite
Quantitative
Assumes infreguent access to areas around Basin and Round Pond.
Trespasser
Adult
Dermal
Onsite
Quantitative
Assumes infreguent access to areas around Basin and Round Pond.
Trespasser
Adolescent
Ingestion
Onsite
Quantitative
Assumes infreguent access to areas around Basin and Round Pond.
Trespasser
Adolescent
Dermal
Onsite
Quantitative
Assumes infreguent access to areas around Basin and Round Pond.
Particulates
Fugitive Dust
Trespasser
Adult
Inhalation
Onsite
Quantitative
Assumes infreguent access to areas around Basin and Round Pond.
Trespasser
Adolescent
Inhalation
Onsite
Quantitative
Assumes infreguent access to areas around Basin and Round Pond.
Surface
Water
Surface Water
Swimming or
Fishing in the Basin
Trespasser
Adolescent
Ingestion
Onsite
Quantitative
Assumes infreguent contact with surface water in the Basin and Round
Pond.
Trespasser
Adolescent
Dermal
Onsite
Quantitative
Assumes infreguent contact with surface water in the Basin and Round
Pond.
Trespasser
Adolescent
Inhalation
Onsite
None
No volatiles related to the site.
Trespasser
Adult
Ingestion
Onsite
Quantitative
Assumes infreguent contact with surface water in the Basin and Round
Pond.
Trespasser
Adult
Dermal
Onsite
Quantitative
Assumes infreguent contact with surface water in the Basin and Round
Pond.
Trespasser
Adult
Inhalation
Onsite
None
No volatiles related to the site.
Fish Tissue
Fish Tissue
Fishing in the
Basin
Trespasser
Adolescent
Ingestion
Onsite
Quantitative
Assumes infreguent fishing in the Basin area.
Trespasser
Adult
Ingestion
Onsite
Quantitative
Assumes infreguent fishing in the Basin area.
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 15. Summary of Chemicals of Potential Concern and Medium-Specific Exposure Point
Concentrations
Scenario Timeframe: Current/Future
Medium: Surface Water
Exposure Medium: Surface Water
Exposure
Point
COPC
Concentration
Detected
Units
Frequency
of Detection
Exposure Point
Concentration
Exposure Point
Concentration
Units
Statistical
Measure
Min
Max
Surface
Water -
Direct
Contact
Mercury
0.0044
0.36
ug/L
42/42
0.169
ug/L
95%
Chebyshev
UCL
Methylmercury
0.000613
0.0053
ug/L
42/42
0.0027
ug/L
95%
Chebyshev
UCL
Hexachloro-
benzene
0.0215
0.0442
ug/L
6/15
0.0396
ug/L
95% KM
(bootstrap)
UCL
DDTR (a)
0.0964
0.214
ug/L
6/15
0.135
ug/L
95% KM (t)
UCL
Key
ug/L: micrograms per liter
(a) DDTR is the sum of 2,4' and 4,4'-isomersofDDTJ DDD, DDE.
Scenario Timeframe: Current/Future
Medium: Surface Water
Exposure Medium: Fish Tissue
Exposure
Point
COPC
Concentration
Detected
Units
Frequency
of Detection
Exposure Point
Concentration
Exposure Point
Concen-tration
Units
Statistical
Measure
Min
Max
Ingestion
of Fish
Tissue
Methylmercury
1.6(a)
3(a)
mg/kg
20/20
2.47
mg/kg
95%
Student's-t
UCL
Hexachloro-
benzene
0.0362
0.135
mg/kg
20/20
0.077
mg/kg
95%
approximate
gamma UCL
DDTR (b)
0.075
0.598
mg/kg
7/7
0.397
mg/kg
95% KM (t)
UCL
Key
mg/kg: milligrams per kilogram
(a) 100% of total mercury analyzed assumed to be methylmercury
(b) DDTR is the sum of 2,4' and 4,4'-isomersofDDT, DDD, DDE.
Scenario Timeframe: Current/Future
Medium: Floodplain Soil
Exposure Medium: Surface Soil
Exposure
Point
COPC
Concentration
Detected
Units
Frequency
of Detection
Exposure Point
Concentration
Exposure
Point
Concentr-
ation Units
Statistical
Measure
Min
Max
Flood-
plain Soil
Mercury
0.061
8.9
mg/kg
39/39
1.58
mg/kg
95% H-UCL
Methylmercury
3.67E-04
8.22E-
03
mg/kg
11/12
NC
NA
NA
Hexachloro-
benzene
0.0011
0.275
mg/kg
7/9
NC
NA
NA
DDTR (a)
0.00375
2.23
mg/kg
14/15
1.23
mg/kg
95% KM
(Chebyshev)
UCL
Note
mg/kg: milligrams per kilogram
NC: exposure point not calculated because this chemical was not a human health COPC in this medium
NA: Not Applicable
(a) DDTR is the sum of 2,4' and 4,4'-isomers of DDT, DDD, DDE.
-------
Table 16. Cancer Toxicity Data Summary
Record of Decision
Olin Mcintosh OU-2 Site
Pathway: Ingestion, Dermal
COPC
Oral Cancer
Slope Factor
Oral Absorption
Efficiency for
Dermal <1>
Adjusted
Dermal Cancer
Slope Factor <2>
Slope Factor
Units
Weight of Evidence /
Cancer Guideline
Description
Source
Date
Mercury (inorganic salts)
NA
0.07
NA
mg/kg-d-1
C
IRIS
06/01/1995
Methylmercury
NA
1.0
NA
mg/kg-d-1
C
IRIS
07/27/2001
Hexachlorobenzene
1.60E+00
1.0
1.60E+00
mg/kg-d1
B2
IRIS
11/01/1996
DDTR
3.40E-01
1.0
3.40E-01
mg/kg-d1
B2
IRIS
05/01/1991
Pathway: Inhalation
Unit Risk
Units
Inhalation
Cancer Slope
Factor
Slope Factor
Units
Weight of Evidence /
Cancer Guideline
Description
Source
Date
Mercury (inorganic salts)
NA
(mg/m3)-1
NA
NA
C
IRIS
06/01/1995
Methylmercury
NA
(mg/m3)-1
NA
NA
C
IRIS
07/27/2001
Hexachlorobenzene
4.6E-01
(mg/m3)-1
NA
NA
B2
IRIS
11/01/1996
DDTR (a)
9.7E-02
(mg/m3)-1
NA
NA
B2
IRIS
05/01/1991
(a) DDT used as a surrogate.
NA = Not Available
(1) Source: RSL Table
(2) Slope Factor / Efficiency
mg/kg-day1 = reciprocal of milligrams per kilogram per day
(mg/nr)1 = reciprocal of milligrams per cubic meter
Weight of Evidence Group:
B2 - Probable human carcinogen - indicates sufficient evidence in animals and inadequate or no evidence in humans
C - Possible human carcinogen
-------
Table 17. Non-Cancer Toxicity Data Summary
Record of Decision
Olin Mcintosh OU-2 Site
Pathway: Ingestion, Dermal
COPC
Chronic/
Oral RfD
Oral RfD Units
Adjusted Dermal
Dermal RfD
Oral Absorption Efficiency
Primary Target
Combined Uncertainty/
Sources of RfD:
Dates of RfD:
Subchronic
Value
RfD (1)
Units
for Dermal (2)
Organ
Modifying Factors
Target Organ
Target Organ
Mercury (inorganic salts)
Chronic
3.0E-04
mg/kg-day
2.1E-05
mg/kg-day
0.07
Immune
1000/1
IRIS
05/01/1995
Methylmercury
Chronic
1.0E-04
mg/kg-day
1.0E-04
mg/kg-day
1.0
CNS
10/1
IRIS
07/27/2001
Hexachlorobenzene
Chronic
8.0E-04
mg/kg-day
8.0E-04
mg/kg-day
1.0
Liver
100/1
IRIS
04/01/1991
DDTR (a)
Chronic
5.0E-04
mg/kg-day
5.0E-04
mg/kg-day
1.0
Liver
100/1
IRIS
02/01/1996
Pathway: Inhalation
COPC
Chronic/
Inhalatipn
Inhalation RfC
Inhalation RfD
Inhalation RfD
Primary Target Organ
Combined Uncertainty/
Sources of RfC-RfD: Target Organ
Dates of RfD:
Subchronic
RfC
Units
Units
Modifying Factors
Target Organ
Mercury (inorganic salts)
Chronic
NA
mg/m3
--
--
NA
NA
IRIS
04/01/1994
Methylmercury
Chronic
NA
mg/m3
--
--
NA
NA
IRIS
07/27/2001
Hexachlorobenzene
Chronic
NA
mg/m3
--
--
NA
NA
IRIS
03/01/1991
DDTR (a)
Chronic
NA
mg/m3
--
--
NA
NA
IRIS
NA
(a) DDT used as a surrogate.
NA = Not Available
(1) Source: RSL Table
(2) Slope Factor / Efficiency
mg/kg-day = milligrams per kilogram per day
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 18. Human Health Risk Characterization Summary - Non-Carcinogens
Scenario Timeframe: Current
Receptor Population: Resident/Trespasser/Fisherman
Receptor Age: Adult
Medium
Exposure
Medium
Exposure
Point
COPC
Primary
Target
Organ
Non-Carcinogenic Hazard Quotient
Ingestion
Inhalation
Dermal
Exposure
Routes
Total
Surface
Water
Surface
Water
Swimming
Mercury
Immune
1.0E-05
NA
1.0E-04
1.1E-04
Methyl mercury
CNS
5.0E-07
NA
5.0E-07
1.0E-06
Hexachlor-
benzene
Liver
9.0E-07
NA
4.0E-04
4.0E-04
DDTR
Liver
5.0E-06
NA
5.0E-03
5.0E-03
Surface Water Hazard Index Total=
5.5E-03
Surface
Soil
Floodplain
Soil
Onsite
Mercury
Immune
1.0E-04
7.0E-06
1.1E-04
DDTR
Liver
6.0E-05
7.0E-06
6.7E-05
Surface Soil Hazard Index Total
1.8E-04
Fish
Tissue
Fish Tissue
Fishing in
Basin
Methyl mercury
CNS
1.4E+00
NA
NA
1.4E+00
Hexachlor-
benzene
Liver
5.5E-03
NA
NA
5.5E-03
DDTR
Liver
4.5E-02
NA
NA
4.5E-02
Fish Ingestion Hazard Index
1.5E+00
Receptor Hazard lndex=
Liver Hazard lndex=
Immune Hazard lndex=
CNS Hazard lndex=
1.5E+00
5.0E-02
2.2E-04
1.4E+00
Key
— : Toxicity criteria are not available to quantitatively address this route of exposure
NA: Route of exposure is not applicable to this medium
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 19. Human Health Risk Characterization Summary - Non-Carcinogens
Scenario Timeframe: Current
Receptor Population: Resident/Trespasser/Fisherman
Receptor Age: Pre-adolescent/Adolescent
Medium
Exposure
Medium
Exposure
Point
COPC
Primary
Target
Organ
Non-Carcinogenic Hazard Quotient
Ingestion
Inhalation
Dermal
Exposure
Routes
Total
Surface
Water
Surface
Water
Swimming
Mercury
Immune
4.0E-05
NA
2.0E-04
2.4E-04
Methyl mercury
CNS
2.0E-06
NA
5.0E-07
2.5E-06
Hexachlor-
benzene
Liver
3.0E-06
NA
4.0E-04
4.0E-04
DDTR
Liver
2.0E-05
NA
6.0E-03
6.0E-03
Surface Water Hazard Index Total=
6.6E-03
Surface
Soil
Floodplain
Soil
Onsite
Mercury
Immune
2.0E-04
—
2.0E-05
2.5E-04
DDTR
Liver
8.0E-05
—
2.0E-05
1.0E-04
Surface Soil Hazard Index Total
3.5E-04
Fish
Tissue
Fish Tissue
Fishing in
Basin
Methyl mercury
CNS
1.0E+00
NA
NA
1.0E+00
Hexachlor-
benzene
Liver
4.0E-03
NA
NA
4.0E-03
DDTR
Liver
4.0E-02
NA
NA
4.0E-02
Fish Ingestion Hazard Index
1.0E+00
Receptor Hazard lndex=
Liver Hazard lndex=
Immune Hazard lndex=
CNS Hazard lndex=
1.0E+00
5.0E-02
4.9E-04
1.0E+00
Key
— : Toxicity criteria are not available to quantitatively address this route of exposure
NA: Route of exposure is not applicable to this medium
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 20. Human Health Risk Characterization Summary - Non-Carcinogens
Scenario 1
Receptor
Receptor
Medium
rimeframe: Fi
Population: R
Age: Adult
Exposure
Medium
iture
esident/Tresp
Exposure
Point
asser/Fisherman
COPC
Primary
Target
Organ
Non-Carcinogenic Hazard Quotient
Ingestion
Inhalation
Dermal
Exposure
Routes
Total
Surface
Water
Surface
Water
Swimming
Mercury
Immune
4.0E-05
NA
5.0E-04
5.4E-04
Methyl mercury
CNS
2.0E-06
NA
2.0E-06
4.0E-06
Hexachlor-
benzene
Liver
3.0E-06
NA
1.0E-03
1.0E-03
DDTR
Liver
2.0E-05
NA
2.0E-02
2.0E-05
Surface Water Hazard Index Total=
1.6E-03
Surface
Soil
Floodplain
Soil
Onsite
Mercury
Immune
5.0E-04
—
3.0E-05
5.3E-04
DDTR
Liver
2.0E-04
—
3.0E-05
2.3E-04
Surface Soil Hazard Index Total
7.6E-04
Fish
Tissue
Fish Tissue
Fishing in
Basin
Methyl mercury
CNS
6.0E+00
NA
NA
6.0E+00
Hexachlor-
benzene
Liver
2.0E-02
NA
NA
2.0E-02
DDTR
Liver
2.0E-01
NA
NA
2.0E-01
Fish Ingestion Hazard Index
6.2E+00
Receptor Hazard lndex=
Liver Hazard lndex=
Immune Hazard lndex=
CNS Hazard lndex=
6.2E+00
2.2E-01
5.3E-04
6.0E+00
Key
— : Toxicity criteria are not available to quantitatively address this route of exposure
NA: Route of exposure is not applicable to this medium
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 21. Human Health Risk Characterization Summary - Non-Carcinogens
Scenario Timeframe: Future
Receptor Population: Resident/Trespasser/Fisherman
Receptor Age: Pre-adolescent/Adolescent
Medium
Exposure
Medium
Exposure
Point
COPC
Primary
Target
Organ
Non-Carcinogenic Hazard Quotient
Ingestion
Inhalation
Dermal
Exposure
Routes
Total
Surface
Water
Surface
Water
Swimming
Mercury
Immune
1.0E-04
NA
6.0E-04
7.0E-04
Methyl mercury
CNS
7.0E-06
NA
2.0E-06
9.0E-06
Hexachlor-
benzene
Liver
1.0E-05
NA
2.0E-03
2.0E-03
DDTR
Liver
7.0E-05
NA
2.0E-02
2.0E-02
Surface Water Hazard Index Total=
2.3E-02
Surface
Soil
Floodplain
Soil
Onsite
Mercury
Immune
7.0E-04
—
8.0E-05
7.8E-04
DDTR
Liver
3.0E-04
—
8.0E-05
3.8E-04
Surface Soil Hazard Index Total
1.2E-03
Fish
Tissue
Fish Tissue
Fishing in
Basin
Methyl mercury
CNS
4.0E+00
NA
NA
4.0E+00
Hexachlor-
benzene
Liver
2.0E-02
NA
NA
2.0E-02
DDTR
Liver
1.0E-01
NA
NA
1.0E-01
Fish Ingestion Hazard Index
4.1E+00
Receptor Hazard lndex=
Liver Hazard lndex=
Immune Hazard lndex=
CNS Hazard lndex=
4.1E+00
1.4E-01
1.5E-03
4.0E+00
Key
— : Toxicity criteria are not available to quantitatively address this route of exposure
NA: Route of exposure is not applicable to this medium
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 22. Human Health Risk Characterization Summary - Carcinogen
Scenario Timeframe: Current
Receptor Population: Resident/Trespasser/Fisherman
Receptor Age: Adult
Medium
Exposure
Medium
Exposure
Point
COPC
Carcinogenic Risks
Ingestion
Inhalation
Dermal
Exposure
Routes Total
Surface
Water
Surface
Water
Swimming
Hexachloro-
benzene
5.1E-10
NA
2.2E-
07
2.2E-07
DDTR
3.7E-10
NA
4.0E-
07
4.0E-07
Surface Water Risk Total=
6.2E-07
Surface
Soil
Floodplain
Soil
Onsite
Hexachloro-
benzene
NA
NA
NA
NA
DDTR
4.0E-09
6.0E-13
5.0E-
10
4.5E-09
Surface Soil Risk Total
4.5E-09
Fish
Tissue
Fish
Tissue
Fishing in
Basin
Hexachloro-
benzene
3E-06
NA
NA
3.0E-06
DDTR
3E-06
NA
NA
3.0E-06
Fish Ingestion Risk Total
6.0E-06
Total Risk=
6.7E-06
Key
-: Toxicity criteria are not available to quantitatively address this route of exposure
NA: Route of exposure is not applicable to this medium
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 23. Human Health Risk Characterization Summary - Carcinogen
Scenario Timeframe: C
Receptor Population: R
Receptor Age: Pre-ado
urrent
esident/Tre:
escent/Ado
apasser/Fisherman
escent
Medium
Exposure
Medium
Exposure
Point
COPC
Carcinogenic Risks
Ingestion
Inhalation
Dermal
Exposure
Routes Total
Surface
Water
Surface
Water
Swimming
Hexachloro-
benzene
6.0E-10
NA
8.0E-08
8.1E-08
DDTR
4.0E-10
NA
2.0E-07
2.0E-07
Surface Water Risk Total=
2.1E-07
Surface
Soil
Floodplain
Soil
Onsite
Hexachloro-
benzene
NA
NA
NA
NA
DDTR
2.0E-09
2.0E-13
5.0E-10
2.5E-09
Surface Soil Risk Total
2.5E-09
Fish
Tissue
Fish
Tissue
Fishing in
Basin
Hexachloro-
benzene
8E-07
NA
NA
8.0E-07
DDTR
9E-07
NA
NA
9.0E-07
Fis
i1ngestion Risk Total
1.70E-06
Total Risk=
2.0E-06
Key
-: Toxicity criteria are not available to quantitatively address this route of exposure
NA: Route of exposure is not applicable to this medium
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 24. Human Health Risk Characterization Summary - Carcinogen
Scenario Timeframe: Future
Receptor Population: Resident/Trespasser/Fisherman
Receptor Age: Adult
Medium
Exposure
Medium
Exposure
Point
COPC
Carcinogenic Risks
Ingestion
Inhalation
Dermal
Exposure Routes
Total
Surface
Water
Surface
Water
Swimming
Hexachloro-
benzene
1.9E-09
NA
8.1E-07
8.1E-07
DDTR
1.4E-09
NA
1.5E-06
1.5E-06
Surface Water Ris
k Total=
2.3E-06
Surface Soil
Floodplain
Soil
Onsite
Hexachloro-
benzene
NA
NA
NA
NA
DDTR
2.0E-08
2.0E-12
2.0E-9
2.2E-08
Surface Soil Risk Total
2.2E-08
Fish Tissue
Fish
Tissue
Fishing in
Basin
Hexachloro-
benzene
1.5E-05
NA
NA
1.5E-05
DDTR
1.5E-05
NA
NA
1.5E-06
Fish Ingestion Risk Total
3.0E-05
Total Risk=
3.2E-05
Key
-: Toxicity criteria are not available to quantitatively address this route of exposure
NA: Route of exposure is not applicable to this medium
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 25. Human Health Risk Characterization Summary - Carcinogen
Scenario Timeframe: Future
Receptor Population: Resident/Trespasser/Fisherman
Receptor Age: Pre-adolescent/Adolescent
Medium
Exposure
Medium
Exposure
Point
COPC
Carcino<
genie Risks
Ingestion
Inhalation
Dermal
Exposure
Routes Total
Surface
Water
Surface
Water
Swimming
Hexachloro-
benzene
2.0E-09
NA
3.0E-07
3.0E-07
DDTR
2.0E-09
NA
6.0E-07
6.0E-07
Surface Water F
lisk Total=
9.0E-07
Surface
Soil
Floodplain
Soil
Onsite
Hexachloro-
benzene
NA
NA
NA
NA
DDTR
8.0E-09
8.0E-13
2.0E-09
1.0E-08
Surface Soil Risk Total
2.5E-09
Fish
Tissue
Fish Tissue
Fishing in
Basin
Hexachloro-
benzene
3.5E-06
NA
NA
3.5E-06
DDTR
3.5E-06
NA
NA
3.5E-06
Fish Ingestion Risk Total
7.0E-06
Total Risk=
8.0E-06
Key
-: Toxicity criteria are not available to quantitatively address this route of exposure
NA: Route of exposure is not applicable to this medium
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 26. Occurrence, Distribution, and Selection of Chemicals of Concern
Exposure Medium: Sediment
Chemical of Potential Concern
Minimum
Maximum
95% UCL of
Background Cone.
Screening
Screening
HQ Value4
COC
Cone.1 (mg/kg)
Cone.1 (mg/kg)
the Mean2
(mg/kg)
Toxicity Value
Toxicity Value
Flag (Y
(mg/kg)
(mg/kg)
Source3
or N)
Mercury
0.965
213
51.0
<0.09
1.06
PEC
200
Y
Methylmercury
0.00142
0.0257
0.00728
NA
NA
-
-
N 5
Hexachlorobenzene
0.0221
34.1
8.29
<0.0005
0.020
PEC
1,705
Y
DDTR
0.066
2.72
1.57
<0.005
0.0025
WSRC
1,088
Y
Exposure Medium: Surface Water
Chemical of Potential Concern
Minimum
Maximum
95% UCL of
Background Cone.
Screening
Screening
HQ Value4
COC
Cone.1 (ug/L)
Cone.1 (ug/L)
the Mean2
(ug/L)
Toxicity Value
Toxicity Value
Flag (Y
(ug/L)
(ug/L)
Source3
or N)
Mercury (total)
0.0044
0.36
0.169
<0.003
0.012
EPA R4
30
Y
Mercury (dissolved)
0.0147
<0.003
0.012
EPA R4
1.2
N 5
Methylmercury
0.000613
0.00553
0.00274
NA
NA
—
-
Y
Hexachlorobenzene
0.0031
0.044
0.0396
<0.001
NA
-
-
Y
DDTR
0.096
0.403
0.135
<0.001
0.001
NAWQC
400
Y
Exposure Medium: Surface Soil
Chemical of Potential Concern
Minimum
Maximum
95% UCL of
Background Cone.
Screening
Screening
HQ Value4
COC
Cone.1 (mg/kg)
Cone.1 (mg/kg)
the Mean2
(mg/kg)
Toxicity Value
Toxicity Value
Flag (Y
(mg/kg)
(mg/kg)
Source3
or N)
Mercury
0.061
8.9
1.60
<0.07
0.1
EPA R4
89
Y
Methylmercury
0.000176
0.0082
NA
NA
0.67
EPA R4
0.01
N
Hexachlorobenzene
0.0011
0.275
NA
<0.0004
0.0025
EPA R4
110
Y
DDTR
0.066
2.23
1.20
<0.002
0.0025
EPA R4
892
Y
Key
Cone. = Concentration
N/A = Not Applicable
Notes
1 Minimum/ maximum detected concentration above the sample quantification limit (SQL)
2 The 95% Upper Confidence Limit (UCL) represents the RME concentration
3 PEC = Sediment Probable Effects Concentration from McDonald et al 2000. Development and Evaluation of Consensus-based Sediment Quality Guidelines for Freshwater
Ecosystems. Arch. Contam. Toxicol. 39: 20-31.
WSRC = Ecological screening value for sediment from Westinghouse Savannah River Company WSCR-TR-98-00110 (2000)
EPA R4 = Ecological Screening Value from EPA Region 4
NAWQC = National Ambient Water Quality Criterion
4 Hazard Quotient (HQ) is defined as Maximum Concentration/ Screening Toxicity Value.
5 Methylmercury is the primary form in which mercury is moved through the food chain. Remedial goals for mercury are developed for Total Mercury (inorganic + methyl).
-------
Record of Decision
Olin Mcintosh OU-2 Site
TABLE 27. Ecological Exposure Pathways of Concern
Exposure
Medium
Sensitive
Environment
Flag (Y or N)
Receptor
Endangered /
Threatened
Species Flag
(Y or N)
Exposures
Routes
Assessment Endpoints
Measurement Endpoints
QUALITATIVE SLERA ENDPOINTS
Sediment
N
1) Benthic
Invertebrates
Direct contact,
ingestion
Protection of Long-term Health and
Reproductive Success of Benthic
Invertebrate Community
Comparison of COC concentrations in
sediment and crayfish tissue to media-
specific toxicity values protective of
benthic invertebrates
Sediment,
Surface
Water
N
2) Fish
Direct contact,
ingestion
Protection of Long-term Health and
Reproductive Success of the Fish
Community
Comparison of COC concentrations in
sediment, surface water, and fish tissue
to media-specific toxicity values
protective offish.
Floodplain
Soil
N
3) Soil dwelling
invertebrates
Direct
Contact,
Ingestion
Protection of Long-term Health and
Reproductive Success of Soil Invertebrates
in Floodplain Soil
Comparison of COC concentrations in
soil to soil toxicity values protective of
soil-dwelling invertebrates
QUANTITATIVE BERA ENDPOINTS
Sediment,
Surface Water
N
4) Aquatic
invertebrate
feeding
mammals
N
Ingestion
Protection of Long-term Health and
Reproductive Success of Insectivorous
Aquatic Mammals
Food chain dose modeling to little brown
bat using COC concentrations in
sediment, surface water, and emergent
aquatic insect tissue
N
5) Carnivorous
aquatic
mammals
N
Ingestion
Protection of Long-term Health and
Reproductive Success of Carnivorous
Aquatic Mammals
Food chain dose modeling to river otter
and mink using COC concentrations in
sediment, surface water, forage fish
tissue, and predatory fish tissue
N
6) Insectivorous
aquatic birds
N
Ingestion
Protection of Long-term Health and
Reproductive Success of Insectivorous
Aquatic Birds
Food chain dose modeling to pied-billed
grebe using COC concentrations in
sediment, surface water, vertebrate
tissue, frog tissue, crayfish tissue,
aquatic insect tissue, crayfish tissue, and
forage fish tissue
N
7) Piscivorous
aquatic birds
N
Ingestion
Protection of Long-term Health and
Reproductive Success of Piscivorous
Aquatic Birds
Food chain dose modeling to belted
kingfisher using COC concentrations in
sediment, surface water, forage fish
tissue, aquatic insect tissue, crayfish
tissue, and amphibian tissue; modeling
to little blue heron using forage fish and
aquatic insect tissue; modeling to great
blue heron using sediment, surface
water, aquatic insect tissue, amphibian
tissue, forage fish tissue, and predatory
fish tissue.
1 of 2
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Record of Decision
Olin Mcintosh OU-2 Site
TABLE 27. Ecological Exposure Pathways of Concern (continued)
Exposure
Medium
Sensitive
Environment
Flag (Y or N)
Receptor
Endangered /
Threatened
Species Flag
(Y or N)
Exposures
Routes
Assessment Endpoints
Measurement Endpoints
N
8) Omnivorous
aquatic birds
N
Ingestion
Protection of Long-term Health and
Reproductive Success of Omnivorous
Aquatic Birds
Food chain dose modeling to wood duck
using COC concentrations in sediment,
surface water, insect tissue, and
terrestrial (floodplain) plant tissue
N
9) Carnivorous
aquatic reptiles
N
Ingestion
Protection of Long-term health and
Reproductive Success of Carnivorous
Aquatic Reptiles
Food chain dose modeling to American
alligator using
N
10) Insectivorous
terrestrial
mammals
N
Ingestion
Protection of Long-term Health and
Reproductive Success of Insectivorous
Terrestrial Mammals
Food chain dose modeling to short-tailed
shrew using COC concentrations in
floodplain soil and terrestrial insect and
spider tissue
Soil
N
11) Omnivorous
terrestrial
mammals
N
Ingestion
Protection of Long-term Health and
Reproductive Success of Omnivorous
Terrestrial Mammals
Food chain dose modeling to raccoon
using COC concentrations in floodplain
soil, terrestrial insect and spider tissue,
vertebrate tissue, and terrestrial
(floodplain) plant tissue
N
12) Herbivorous
terrestrial
mammals
N
Ingestion
Protection of Long-term Health and
Reproductive Success of Herbivorous
Terrestrial Mammals
Food chain dose modeling to pine vole
using COC concentrations in floodplain
soil and terrestrial (floodplain) plant
tissue
N
13) Insectivorous
terrestrial birds
N
Ingestion
Protection of Long-term Health and
Reproductive Success of Insectivorous
Terrestrial Birds
Food chain dose modeling to Carolina
wren using COC concentrations in
floodplain soil and terrestrial insect and
spider tissue
2 of 2
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Record of Decision
Olin Mcintosh OU-2 Site
Table 28. COC Concentrations Expected to Provide Adequate Protection of Ecological Receptors
Exposure
Medium
COC
Protective Level1
Units
Basis2
Assessment Endpoint
Sediment
Mercury
1.6 to 10.7
mg/kg
Lower end of range based on geometric mean of
NOAEL and LOAEL RGs for little blue heron derived
using sediment to fish BSAF uptake model. Upper
end of range based on NOAEL RG derived from
SERAFM mercury uptake model.
Protection of piscivorous birds (little
blue heron)
HCB
7.6
mg/kg
NOAEL
Protection of piscivorous mammals
(mink)
DDTR
0.21 (protection of predatory fish)
0.32 - 0.91 (protection of
piscivorous birds)
0.63 (protection of forage fish)
mg/kg
Predatory fish goal based on sediment concentration
resulting in biomagnification into piscivorous fish
exceeding the 10th percentile LER fish tissue
protective goal. Range of goals based on protection
of piscivorous birds ingesting fish at OU-2. Forage
fish goal based on sediment concentration resulting in
forage fish tissue concentration exceeding the 10th
percentile LER fish protective level.
Protection of fish;
Protection of piscivorous birds (little
blue heron and great blue heron)
Floodplain
Soil
Mercury
0.54-1.9
mg/kg
RG range based on NOAEL PRG for Carolina wren
modeled with varying diets of different invertebrate
types.
Protection of terrestrial
insectivorous birds
DDTR
0.18-1.12
mg.kg
RG range based on geometric mean of NOAL and
LOAEL PRGs for Carolina wren modeled with varying
diets of different invertebrate types.
Protection of terrestrial
insectivorous birds
Fish Tissue
(forage fish)
Mercury
0.20-0.28
mg/kg
Lower end of range represents piscivorous bird goal
based on geometric mean of NOAEL and LOAEL
PRGs for little blue heron. Upper end of range
represents 10th percentile value protective offish.
Protection offish and piscivorous
birds
DDTR
0.23 (protection of predatory fish)
0.42 - 0.52 (protection of
piscivorous birds)
mg/kg
Low value (0.23) represents forage fish concentration
resulting in biomagnification into bass tissue equal to
fish tissue protective level for bass. Piscivorous bird
range based on protection of birds using the
geometric mean of the NOAEL and LOAEL.
Protection offish and protection of
piscivorous birds (little blue heron
and great blue heron)
Fish Tissue
(Large Mouth
Bass)
Mercury
0.28 (Predatory Fish RG for fish
protection - whole body);
0.43 (Predatory Fish RG for
piscivorous eating birds - whole
body);
0.3 (Predatory Fish human
health RG - filets)
mg/kg
Fish protection goal based on t-TEL from Beckvar et
al, 2005)
Piscivorous bird goal based on geometric mean of
NOAEL and LOAEL RGs for great blue heron.
Human health goal is ARAR for human consumption.
Protection offish and protection of
piscivorous birds (little blue heron
and great blue heron). Protection of
human health.
DDTR
0.64
mg/kg
Based on T-TEL from
Protection of Fish
Notes
1 A range of levels may be provided. 2 Basis of Selection of protection level.
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Record of Decision
Olin Mcintosh OU-2 Site
Table 29. Olin OU-2 Cleanup Levels for Chemicals of Concern
Sediment
Chemical of
Concern
Cleanup Level
Basis for Cleanup Level
Risk at Cleanup Level
Mercury
3 mg/kg
Risk Assessment - weight of evidence based on
protection of piscivorous bird species at LOAEL
Human Health HQ = 0.29 (a)
Ecological HQ = 0.43 (b)
HCB
7.6 mg/kg
Risk Assessment - protection of piscivorous
mammals (direct contact with sediment) at LOAEL
Human Health ILCR = 1E-05 (c)
Ecological HQ = 1 (d)
DDTR
0.21 mg/kg
Risk Assessment - protection of predatory fish at
threshold effects level
Human Health HQ < 1
Ecological HQ = 1
Surface Water
Chemical of
Concern
Cleanup Level
Basis for Cleanup Level
Risk at Cleanup Level
Mercury
(dissolved)
0.012 ug/L
ARAR
NA
DDTR
0.0001 ug/L
ARAR
NA
HCB
0.0002 ug/L
ARAR
NA
Floodplain Soil
Chemical of
Concern
Cleanup Level
Basis for Cleanup Level
Risk at Cleanup Level
Mercury
1.7 mg.kg
Risk Assessment - protection of insectivorous birds
based on diet of crawling insects and spiders at
LOAEL
Human Health HQ = 0.001 (e)
Ecological HQ = 1 (f)
DDTR
0.63 mg/kg
Risk Assessment - protection of insectivorous birds
based on diet of crawling insects and spiders at
LOAEL
Human Health ILCR = 1E-08 (g)
Ecological HQ = 1 (f)
1 of 2
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Record of Decision
Olin Mcintosh OU-2 Site
Table 29. Olin OU-2 Cleanup Levels for Chemicals of Concern (continued)
Fish Tissue
Chemical of
Concern
Cleanup Level
Basis for Cleanup Level
Risk at Cleanup Level
Mercury
0.2 mg/kg (mosquitofish)
0.3 mg/kg (largemouth
bass fillet)
0.28 mg/kg (largemouth
bass whole body)
Risk Assessment
Mosquitofish goal based on protection of piscivorous
birds at LOAEL
Largemouth bass filet goal based on Human Health
ARAR
Largemouth bass whole body goal based on
protection offish at 10th percentile effects level
Ecological HQ = 1 (mosquitofish
and whole body bass)
Human Health HQ < 1 based on
fish tissue ARAR (largemouth bass
fillet)®
DDTR
0.23 mg/kg (mosquitofish)
0.64 mg/kg (largemouth
bass)
Risk Assessment
Mosquitofish goal is body burden threshold effects
level based on protection of predatory fish feeding on
mosquitofish
Largemouth bass goal is body burden threshold
effects level based on protection of bass and other
pisicvorous fish
Ecological HQ = 1 (forage fish)
Ecological HQ = 1 (largemouth
bass)
Notes:
NA - Not Applicable
(a) Human health hazard quotient for mercury in sediment based on future time-frame fisherman scenario, which was the most sensitive non-
cancer exposure scenario identified in the human health risk assessment.
(b) Ecological hazard quotient for mercury in sediment based on risk to little blue heron as a surrogate for piscivorous birds
(c) Human health ILCR for HCB in sediment based on future time-frame fisherman scenario, which was the most sensitive cancer exposure
scenario identified in the human health risk assessment.
(d) Ecological hazard quotient for HCB in sediment based on risk to mink as a surrogate for carnivorous mammals
(e) Human health HQ for mercury in floodplain soil based on future-use adolescent trespasser scenario, which was the most sensitive non-
cancer exposure scenario identified I the human health risk assessment
(f) Ecological HQ for mercury in floodplain soil based on risk to Carolina wren as a surrogate for insectivorous birds
(g) Human health ILCR for DDTR in floodplain soil based on future-use adult trespasser scenario, which was the most sensitive non-cancer
exposure scenario identified I the human health risk assessment
(h) Ecological HQ for DDTR in floodplain soil based on risk to Carolina wren as a surrogate for insectivorous birds
(i) The HHRA calculated an HI of 6 based on an exposure concentration of 2.47 mg/kg, the concentration for an HI of 1 would be 2.47/6 =
0.4 mg/kg.
2 of 2
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Record of Decision
Olin Mcintosh OU-2 Site
Table 30. Cost Estimate Summary
Alternative 2A
IN SITU CAPPING
Site: Olin Mcintosh Operable Unit 2
Location: Mcintosh, Alabama
Phase: Feasibility Study
Alternative 2A consists of capping of sediment and institutional controls (ICs). Timeframe is 30 years. Capital
Costs occur in Year 0, periodic cost frequency is listed at the bottom of the table. This cost estimate table is for
an in situ cap with different cap materials and thicknesses.
Base Year: 2012
CAPITAL COSTS
DESCRIPTION
QTY UNITS
UNIT COST
TOTAL1
REMARKS
Implementation of ICs
1 LS
$1,600
$1,600
SUBTOTAL
$1,600
Capping Remedy
Design and Treatability Study
1 LS
$60,000
$60,000
Cap Placement
1 LS
$11,987,511
$11,987,511 -$20,783,368
SUBTOTAL
$12,049,111 -$20,844,968
Post Construction Confirmation Sampling
Cap Sediment Sampling
1 LS
$20,214
$20,214
Surface Water Sampling
1 LS
$10,359
$10,359
SUBTOTAL
$12,079,683-$20,875,541
Contingency
1 per cent
$12,049,111
$120,491
1 % of Scope
SUBTOTAL
$12,200,174-$21,083,991
Management
Project Management
1 per cent
$12,049,111
$120,491
1 % of Scope
Construction Management
1 per cent
$12,049,111
$120,491
1 % of Scope
SUBTOTAL
$12,441,157-$21,500,890
TOTAL CAPITAL COSTS
$12,400,000 $21,500,000
1: Higher end of the cost range is shown in sixth column.
1 of 7
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Record of Decision
Olin Mcintosh OU-2 Site
Table 30. Cost Estimate Summary (continued)
ANNUAL COSTS DESCRIPTION
QTY
UNITS
UNIT COST
TOTAL
REMARKS
Inspection and Maintenance
SUBTOTAL
1
LS
$3,500
$3,500
$3,500
Contingency
SUBTOTAL
10
per cent
$3,500
$350
$3,850
10% of Scope
Management
Project Management
SUBTOTAL
5
per cent
$3,500
$175
$4,025
5% of Scope
TOTAL ANNUAL COST
$4,000
PERIODIC COSTS
YEAR
Fish Sampling and Analysis
1
LS
$9,236
$9,236
Spiders/Insects Sampling & Analysis
1
LS
$11,320
$11,320
Surface Water Sampling & Analysis
4
LS
$10,359
$41,436
SUBTOTAL
$61,992
Contingency
SUBTOTAL
10
per cent
$61,992
$6,199
$68,192
10% of Scope
Management
Project Management
SUBTOTAL
1
5
per cent
$61,992
$3,100
$71,291
5% of Scope
Fish Sampling and Analysis
1
LS
$9,236
$9,236
Spiders/Insects Sampling & Analysis
1
LS
$11,320
$11,320
Surface Water Sampling and Analysis
1
LS
$10,359
$10,359
SUBTOTAL
$30,915
Contingency
SUBTOTAL
10
per cent
$30,915
$3,092
$34,007
10% of Scope
Management
Project Management
SUBTOTAL
2
5
per cent
$30,915
$1,546
$35,553
5% of Scope
2 of 7
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Record of Decision
Olin Mcintosh OU-2 Site
Table 30. Cost Estimate Summary (continued)
DESCRIPTION
YEAR
QTY
UNITS
UNIT COST
TOTAL
REMARKS
Fish Sampling and Analysis
1
LS
$9,236
$9,236
Spiders/Insects Sampling & Analysis
1
LS
$11,320
$11,320
Surface Water Sampling and Analysis
1
LS
$10,359
$10,359
SUBTOTAL
$30,915
Contingency
10
per cent
$30,915
$3,092
10% of Scope
SUBTOTAL
$34,007
Management
Project Management
5
per cent
$30,915
$1,546
5% of Scope
SUBTOTAL
3
$35,553
Pre-5-Year Review Report Monitoring
Topographic Survey
1
LS
$10,070
$10,070
Sediment Core Sampling
1
LS
$20,214
$20,214
Fish Sampling and Analysis
1
LS
$9,236
$9,236
Spiders/Insects Sampling & Analysis
1
LS
$11,320
$11,320
Surface Water Sampling and Analysis
1
LS
$10,359
$10,359
SUBTOTAL
$61,199
Contingency
10
per cent
$61,199
$6,120
10% of Scope
SUBTOTAL
$67,319
Management
Project Management
5
per cent
$61,199
$3,060
5% of Scope
SUBTOTAL
4
$70,379
Surface Water Sampling and Analysis
1
LS
$10,359
$10,359
Fish Sampling and Analysis
1
LS
$9,236
$9,236
Spiders/ Insects Sampling & Analysis
1
LS
$11,320
$11,320
5-Year Review Report
1
LS
$5,000
$5,000
SUBTOTAL
$35,915
Contingency
10
per cent
$35,915
$3,592
10% of Scope
SUBTOTAL
$39,507
3 of 7
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Record of Decision
Olin Mcintosh OU-2 Site
Table 30. Cost Estimate Summary (continued)
DESCRIPTION
YEAR
QTY
UNITS
UNIT COST
TOTAL
REMARKS
Management
Project Management
5
per cent
$35,915
$1,796
5% of Scope
SUBTOTAL
5
$41,303
Annual Surface Water Sampling & Analysis
Surface Water Sampling and Analysis
1
LS
$10,359
$10,359
SUBTOTAL
$10,359
Contingency
10
per cent
$10,359
$1,036
10% of Scope
SUBTOTAL
$11,395
Management
Project Management
5
per cent
$10,359
$518
5% of Scope
SUBTOTAL
6
$11,913
Annual Surface Water Sampling & Analysis
1
LS
$11,913
$11,913
Same as Year 6
SUBTOTAL
7
$11,913
Annual Surface Water Sampling & Analysis
1
LS
$11,913
$11,913
Same as Year 6
SUBTOTAL
8
$11,913
Pre-5-Year Review Report Monitoring
Topographic Survey
1
LS
$10,070
$10,070
Sediment Core Sampling
1
LS
$20,214
$20,214
Fish Sampling and Analysis
1
LS
$9,236
$9,236
Spiders/Insects Sampling & Analysis
1
LS
$11,320
$11,320
Surface Water Sampling and Analysis
1
LS
$10,359
$10,359
SUBTOTAL
$61,199
Contingency
10
per cent
$61,199
$6,120
10% of Scope
SUBTOTAL
$67,319
Management
Project Management
5
per cent
$61,199
$3,060
5% of Scope
SUBTOTAL
9
$70,379
4 of 7
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Record of Decision
Olin Mcintosh OU-2 Site
Table 30. Cost Estimate Summary (continued)
DESCRIPTION
YEAR
QTY
UNITS
UNIT
COST
TOTAL
COST
REMARKS
5-Year Review Report & Annual Surface Water
Monitoring
5-Year Review Report
1
LS
$5,000
$5,000
Surface Water Sampling and Analysis
SUBTOTAL
1
LS
$10,359
$10,359
$15,359
Contingency
SUBTOTAL
10
per
cent
$15,359
$1,536
$16,895
10% of Scope
Management
Project Management
SUBTOTAL
10
5
per
cent
$15,359
$768
$17,663
5% of Scope
Annual Surface Water Sampling & Analysis
SUBTOTAL
11
1
LS
$11,913
$11,913
$11,913
Same as Year 6
Annual Surface Water Sampling & Analysis
SUBTOTAL
12
1
LS
$11,913
$11,913
$11,913
Same as Year 6
Annual Surface Water Sampling & Analysis
SUBTOTAL
13
1
LS
$11,913
$11,913
$11,913
Same as Year 6
Pre-5-Year Review Report Monitoring
SUBTOTAL
14
1
LS
$70,379
$70,379
$70,379
Same as Year 9
5-Year Review Report & Annual SW Monitoring
1
LS
$17,663
$17,663
Same as Year
10
SUBTOTAL
15
$17,663
Annual Surface Water Sampling & Analysis
SUBTOTAL
16
1
LS
$11,913
$11,913
$11,913
Same as Year 6
Annual Surface Water Sampling & Analysis
SUBTOTAL
17
1
LS
$11,913
$11,913
$11,913
Same as Year 6
Annual Surface Water Sampling & Analysis
SUBTOTAL
18
1
LS
$11,913
$11,913
$11,913
Same as Year 6
Pre-5-Year Review Report Monitoring
SUBTOTAL
19
1
LS
$70,379
$70,379
$70,379
Same as Year 9
5-Year Review Report & Annual SW Monitoring
1
LS
$17,663
$17,663
Same as Year
10
SUBTOTAL
20
$17,663
Annual Surface Water Sampling & Analysis
SUBTOTAL
21
1
LS
$11,913
$11,913
$11,913
Same as Year 6
Annual Surface Water Sampling & Analysis
SUBTOTAL
22
1
LS
$11,913
$11,913
$11,913
Same as Year 6
Annual Surface Water Sampling & Analysis
SUBTOTAL
23
1
LS
$11,913
$11,913
$11,913
Same as Year 6
5 of 7
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Record of Decision
Olin Mcintosh OU-2 Site
Table 30. Cost Estimate Summary (continued)
DESCRIPTION YEAR
QTY
UNITS
UNIT COST
TOTAL COST
REMARKS
Pre-5-Year Review Report Monitoring
SUBTOTAL
24
1
LS
$70,379
$70,379
$70,379
Same as Year 9
5-Year Review Report & Annual SW Monitoring
SUBTOTAL 25
1
LS
$17,663
$17,663
$17,663
Same as Year 10
Annual Surface Water Sampling & Analysis
SUBTOTAL
26
1
LS
$11,913
$11,913
$11,913
Same as Year 6
Annual Surface Water Sampling & Analysis
SUBTOTAL
27
1
LS
$11,913
$11,913
$11,913
Same as Year 6
Annual Surface Water Sampling & Analysis
SUBTOTAL
28
1
LS
$11,913
$11,913
$11,913
Same as Year 6
Pre-5-Year Review Report Monitoring
SUBTOTAL
29
1
LS
$70,379
$70,379
$70,379
Same as Year 9
5-Year Review Report & Annual SW Monitoring
SUBTOTAL
1
30
LS
$17,663
$17,663
$17,663
Same as Year 10
6 of 7
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Record of Decision
Olin Mcintosh OU-2 Site
Table 30. Cost Estimate Summary (continued)
PRESENT VALUE ANALYSIS (AT DISCOUNT RATE OF 7%)
COST TYPE
YEAR
TOTAL COST
TOTAL COST PER
YEAR
DISCOUNT
FACTOR
PRESENT VALUE
Capital Costs
0
$12,400,000 -$21,500,000
NA
1.000
$12,400,000 -$21,500,000
Annual O&M
1-30
$120,000
$4,000
12.409
$49,636
Periodic Cost
1
$71,291
$71,291
0.935
$66,627
Periodic Cost
2
$35,553
$35,553
0.873
$31,053
Periodic Cost
3
$35,553
$35,553
0.816
$29,022
Periodic Cost
4
$70,379
$70,379
0.763
$53,692
Periodic Cost
5
$41,303
$41,303
0.713
$29,448
Periodic Cost
6
$11,913
$11,913
0.666
$7,938
Periodic Cost
7
$11,913
$11,913
0.623
$7,419
Periodic Cost
8
$11,913
$11,913
0.582
$6,933
Periodic Cost
9
$70,379
$70,379
0.544
$38,281
Periodic Cost
10
$17,663
$17,663
0.508
$8,979
Periodic Cost
11
$11,913
$11,913
0.475
$5,660
Periodic Cost
12
$11,913
$11,913
0.444
$5,289
Periodic Cost
13
$11,913
$11,913
0.415
$4,943
Periodic Cost
14
$70,379
$70,379
0.388
$27,294
Periodic Cost
15
$17,663
$17,663
0.362
$6,402
Periodic Cost
16
$11,913
$11,913
0.339
$4,035
Periodic Cost
17
$11,913
$11,913
0.317
$3,771
Periodic Cost
18
$11,913
$11,913
0.296
$3,525
Periodic Cost
19
$70,379
$70,379
0.277
$19,460
Periodic Cost
20
$17,663
$17,663
0.258
$4,564
Periodic Cost
21
$11,913
$11,913
0.242
$2,877
Periodic Cost
22
$11,913
$11,913
0.226
$2,689
Periodic Cost
23
$11,913
$11,913
0.211
$2,513
Periodic Cost
24
$70,379
$70,379
0.197
$13,875
Periodic Cost
25
$17,663
$17,663
0.184
$3,254
Periodic Cost
26
$11,913
$11,913
0.172
$2,051
Periodic Cost
27
$11,913
$11,913
0.161
$1,917
Periodic Cost
28
$11,913
$11,913
0.150
$1,792
Periodic Cost
29
$70,379
$70,379
0.141
$9,893
Periodic Cost
30
$17,663
$17,663
0.131
$2,320
$13,393,000 - 22,493,000 $12,857,000 - 21,957,000
Total Cost (Capital + O&M) $13,400,000 - $22,500,000
Total Present Value of Alternative 12,900,000 - $22,000,000
Note: Totals rounded to the nearest $100,000.
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Record of Decision
Olin Mcintosh OU-2 Site
Table 31. Chemical-Specific Applicable and Relevant and Appropriate Requirements and To-Be Considered Guidance (TBC)
Action/Media
Ue(|iiiremenls
PivmiuisiU'
( ilalion
Risk-based Fish Tissue Residue
Criterion for Mercury
Recommends a fish tissue residue water quality
criterion of 0.3 mg methylmercury/kg.
Mercury and/or
methylmercury in fish tissue
residue - To Be Considered
(TBC)
U.S. EPA, Office of Science and
Tech., Office of Water, EPA-823-
R-01-001, Final Water Quality
Criterion for the Protection of
Human Health: Methylmercury
(Jan. 2001).
Protection of surface water
State waters shall be free from substances attributable
to sewage, industrial wastes or other wastes in
concentrations or combinations which are toxic or
harmful to human, animal or aquatic life to the extent
commensurate with the designated usage of such
waters.
Pollution of waters of the
State of Alabama, as defined
by ADEM Admin. Code r.
335-6-10-.02- relevant and
appropriate
ADEM Admin. Code r. 335-6-10-
.06(c) Minimum Conditions
Applicable to All State Waters
Toxic substances attributable to sewage, industrial
wastes, or other wastes shall be only in such amounts,
whether alone or in combination with other substances,
as will not exhibit acute toxicity or chronic toxicity, as
demonstrated by effluent toxicity testing or by
application of numeric criteria given in ADEM Admin.
Code r. 335-6-10-.07, to fish and aquatic life, including
shrimp and crabs in estuarine or salt waters or the
propagation thereof.
Pollution of waters of the
State of Alabama classified for
Fish and Wildlife use per
ADEM Admin. Code r. 335-6-
11-.02 - relevant and
appropriate
ADEM Admin. Code r. 335-6-10-
,09(5)(e)(5) Specific Water
Quality Criteria
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Olin Mcintosh OU-2 Site
Table 31. Chemical-Specific Applicable and Relevant and Appropriate Requirements and To-Be Considered Guidance (TBC)
Aclion/Mcdiii
Ki(|uiiviiH'ii(s
PivmiuisiU'
( il;ilion
There shall be no turbidity of other than natural
origin that will cause substantial visible contrast
with the natural appearance of waters or interfere
with any beneficial uses which they serve.
Furthermore, in no case shall turbidity exceed 50
[NTU] above background. Background will be
interpreted as the natural condition of the
receiving waters without the influence of man-
made or man-induced causes. Turbidity levels
caused by natural runoff will be included in
establishing background levels.
Discharges to waters of the
State of Alabama classified
for Fish and Wildlife useper
ADEM Admin. Code r. 335-
6-11-.02 - relevant and
appropriate
ADEM Admin. Code r. 335-6-
10-.09(5)(e)(9) Specific Water
Quality Criteria
Protection of surface water
con't
Concentrations of toxic pollutants in State waters
shall not exceed the criteria indicated to the extent
commensurate with the designated usage of such
waters:
• 4,4'-DDD: 0.0002 |jg/L1
• 4,4'-DDE: 0.0001 |jg/L1
• 4,4'-DDT: 0.001 |jg/L2
• 4,4'-DDT: 0.0001 |jg/L1
• Hexachlorobenzene: 0.0002 |jg/L1
• Mercury: 0.012 |jg/L2
• Mercury: 0.042 |jg/L3
Concentrations of toxic
pollutants in waters of the
State of Alabama as
defined by ADEM Admin.
Code r. 335-6-10-.02 -
relevant and appropriate
ADEM Admin. Code r. 335-6-
10-.07(1), Table 17bx/c
Pollutant Criteria
1 As calculated by Eq. 19 specified in ADEM Admin. Coder. 335-6-10-.07(l)(d)(2)(ii), relating to calculation of human health criteria for consumption of fish only for those toxic pollutants
classified by EPA as carcinogens, applicable to all waters of the State of Alabama. See ADEM Admin. Code r. 335-6-10-.07(l)(e).
2 This is the chronic freshwater criteria for protection of aquatic life. The criterion for 4,4'-DDT applies to DDT and it metabolites (DDTR).
3 As calculated by Eq. 17 specified in ADEM Admin. Code r. 335-6-10-.07(l)(d)(l)(ii), relating to calculation of human health criteria for consumption offish only for those toxic pollutants
classified by EPA as non-carcinogens, applicable to all waters of the State of Alabama. See ADEM Admin. Code r. 335-6-10-.07(l)(e).
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Record of Decision
Olin Mcintosh OU-2 Site
Table 31. Chemical-Specific Applicable and Relevant and Appropriate Requirements and To-Be Considered Guidance (TBC)
Aclion/Mcdiii
Ki(|uiiviiH'ii(s
PivmiuisiU'
( il;ilion
Recommends the following concentration shall not
be exceeded.
• DDTR: 0.001 |jg/L4
Presence of toxic pollutant
in waters of the State -
TBC
EPA 1980 Criteria Document
and
Quality Criteria for Water
1986 (EPA 440/5-86-001)
4 This criterion applies to DDT and its six metabolites (i.e., the total concentration of DDT and its metabolites should not exceed this value).
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Record of Decision
Olin Mcintosh OU-2 Site
Table 32. Action-Specific Applicable and Relevant and Appropriate Requirements and To-Be-Considered Guidance
Action
Kc(|iiircmcnls
Prcrcjiuisilc
( ilalion
(icncral Construction Standards — All Land Disturbing Activities
Activities causing
stormwater runoff (e.g.,
clearing, grading,
excavation)
Shall fully implement and regularly maintain effective best
management practices (BMPs) to the maximum extent practicable,
and in accordance with the operator's Construction Best
Management Practices Plan (CBMPP).
Appropriate, effective pollution abatement/prevention facilities,
structural and nonstructural BMPs, and management strategies
shall be fully implemented prior to and concurrent with
commencement of the regulated activities and regularly
maintained during construction as needed at the site to meet or
exceed the requirements of this chapter until construction is
complete, effective reclamation and/or stormwater quality
remediation is achieved.
NOTE - CBMPP will be included as part of a CERCLA document
such as the Remedial Design or Remedial Action Work Plan.
All new and existing construction
activities as defined in ADEM
Admin. Code r. 335-6-12-.02(e)
disturbing one (1) acre or more in
size - applicable
ADEM Admin. Code r.
335-6-12-.05(2)
The operator shall take all reasonable steps to prevent and/or
minimize, to the maximum extent practicable, any discharge in
violation of this chapter or which has a reasonable likelihood of
adversely affecting the quality of groundwater or surface water
receiving the discharge(s).
ADEM Admin. Code r.
335-6-12-.06(4)
Implement a comprehensive CBMPP appropriate for site
conditions consistent with the substantive requirements of ADEM
Admin. Code r. 335-6-12-.21 that has been prepared and certified
by a Qualified Credentialed Professional (QCP).
ADEM Admin. Code r.
335-6-12-.21(2)(a) & (b)
The CBMPP shall include a description of appropriate, effective
water quality BMPs to be implemented at the site as needed to
ensure compliance with this chapter and include but not limited to
the measures provided in subsections 1. thru 14.
BMPs shall be designed, implemented, and regularly maintained to
provide effective treatment of discharges of pollutants in
stormwater resulting from runoff generated by probable storm
ADEM Admin. Code r.
335-6-12-.21(4)
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Record of Decision
Olin Mcintosh OU-2 Site
Table 32. Action-Specific Applicable and Relevant and Appropriate Requirements and To-Be-Considered Guidance
Action
Kcqiiircmcnls
Prcrcqiiisile
( ilalion
events expected/predicted during construction disturbance based
on historic precipitation information, and during extended periods
of adverse weather and seasonal conditions
Activities causing
fugitive dust emissions
Shall not cause, suffer, allow or permit any materials to be
handled, transported, or stored; or a building, its appurtenances, or
a road to be used . . . without taking reasonable precautions to
prevent particulate matter from becoming airborne.
Shall not cause or permit the discharge of visible fugitive dust
emissions beyond the lot line of the property on which the
emissions originate.
Fugitive emissions from
construction operations, grading,
or the clearing of land - TBC
ADEM Admin. Code r.
335-3-4-.02(1) & (2)5
In-Situ Capping of Contaminated Sediments
Design of in-situ
subaqueous cap of
contaminated sediments
Provides guidance for planning and design of in-situ, subaqueous
capping projects, including cap design, equipment and placement
techniques, and monitoring and management considerations.
In-situ, subaqueous capping of
contaminated sediments - TBC
U.S. Army Corps of
Engineers, Tech. Report
DOER-1, Guidance for
Subaqueous Dredged
Material Capping (1998).
5 ADEM Admin. Code r. 335-3-4-.02(1) and (2) were held unconstitutional for being unduly vague (335-3-4-.02(1)) and too restrictive (335-3-4-.02(2)). See Ross Neelev Express. Inc. v.
Ala. Dep't of Envt.1. Mgmt.. 437 So.2d 82 (Ala. 1983).
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Record of Decision
Olin Mcintosh OU-2 Site
Table 32. Action-Specific Applicable and Relevant and Appropriate Requirements and To-Be-Considered Guidance
Action
Kcqiiircmenls
Prcrcqiiisile
( ilalion
II uslc ( liaraderizalion — Primary 11 ds/es (e.^.. contaminated sediments and soil samples) and Secondary H astes (e.g., decon u asleuaters)
Cliaracleri/aliou of
solid waste
Musi determine if solid \\nslc is e\cluded liom regulation under
40 C.F.R. § 261.4(b); and
Determine if waste is listed as hazardous waste under subpart D
40 C.F.R. Part 261.
Generation of solid waste as
defined in 40 C.F.R. § 26 f .2 -
applicable
4(1 C r k £ :<.:.l Ita; and
(b)
ADEM Admin. Code r.
335-14-3-01(2)
Must determine whether the waste is (characteristic waste)
identified in subpart C of 40 C.F.R. part 261by either:
(1) Testing the waste according to the methods set forth in
subpart C of 40 C.F.R. part 261, or according to an
equivalent method approved by the Administrator under 40
C.F.R. 260.21; or
(2) Applying knowledge of the hazard characteristic of the
waste in light of the materials or the processes used.
40 C.F.R. § 262.11(c)
ADEM Admin. Code r.
335-14-3-.01(2)(c)
Must refer to Parts 261, 262, 264, 265, 266, 268, and 273 of
Chapter 40 for possible exclusions or restrictions pertaining to
management of the specific waste.
Generation of solid waste which
is determined to be hazardous
waste - applicable
40 C.F.R. § 262.11(d)
ADEM Admin. Code r.
335-14-3-.01(2)(d)
Characterization of
hazardous waste
Must obtain a detailed chemical and physical analysis on a
representative sample of the waste(s), which at a minimum
contains all the information that must be known to treat, store, or
dispose of the waste in accordance with pertinent sections of 40
C.F.R. Parts 264 and 268.
Generation of RCRA-hazardous
waste for storage, treatment or
disposal - applicable
40 C.F.R. § 264.13(a)(1)
ADEM 335-14-5-
•01(1)0X2)
Determinations for
management of
hazardous waste
Must determine each EPA Hazardous Waste Number (waste code)
applicable to the waste in order to determine the applicable
treatment standards under 40 C.F.R. Part 268 el seq.
Note: This determination may be made concurrently with the
hazardous waste determination required in Sec. 262.11 of this
chapter.
Generation of hazardous waste
for storage, treatment or disposal
- applicable
40 C.F.R. § 268.9(a)
ADEM Admin. Code r.
33-14-9-.01
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Olin Mcintosh OU-2 Site
Table 32. Action-Specific Applicable and Relevant and Appropriate Requirements and To-Be-Considered Guidance
Action
Kcqiiircmenls
Prcrcqiiisile
( ilalion
Determinations for
management of
hazardous waste con't
Must determine the underlying hazardous constituents [as defined
in 40 C.F.R. § 268.2(i)] in the waste.
Generation of RCRA
characteristic hazardous waste
(and is not D001 non-wastewaters
treated by CMBST, RORGS, or
POLYM of Section 268.42 Table
1) for storage, treatment or
disposal - applicable
40 C.F.R. § 268.9(a)
ADEM Admin. Code r.
33-14-9-.01
Must determine if the hazardous waste meets the treatment
standards in 40 C.F.R. §§ 268.40, 268.45, or 268.49 by testing in
accordance with prescribed methods or use of generator
knowledge of waste.
Note: This determination can be made concurrently with the
hazardous waste determination required in 40 C.F.R. 262.11.
40 C.F.R. § 268.7(a)
ADEM Admin. Code r.
33-14-9-.01
II tislc Storage— Primary H astes (e.g.. contaminated sediments and soil samples and Secondary Wastes (e.^.. decon wastewaters)
Temporary onsite
storage of hazardous
waste in containers
A generator may accumulate hazardous waste at the facility
provided that:
• Waste is placed in containers that comply with
40 CFR 265.171-173; and
• The date upon which accumulation begins is clearly
marked and visible for inspection on each container; and
• Container is marked with the words "hazardous waste";
Accumulation of RCRA
hazardous waste on site as
defined in 40 CFR 260.10 -
applicable
40 C.F.R. §
262.34(a)(l)(i);
ADEM Admin. Code r.
335-14-3-.03(5)(a)l(i)
40 C.F.R. § 262.34(a)(2)
&(3);
ADEM Admin. Code r.
335-14-3-
•03(5)(a)(2)&(3)
Use and management of
hazardous waste in
containers
If container is not in good condition (e.g. severe rusting, structural
defects) or if it begins to leak, must transfer waste into container in
good condition.
Storage of RCRA hazardous
waste in containers - applicable
40 C.F.R. §265.171
ADEM Admin. Code r.
335-14-5-.09(2)
Use container made or lined with materials compatible with waste
to be stored so that the ability of the container is not impaired.
40 C.F.R. §265.172
ADEM Admin. Code r.
335-14-5-.09(3)
Use and management of
hazardous waste in
containers con't
Keep containers closed during storage, except to add/remove
waste.
Storage of RCRA hazardous
waste in containers- applicable
40 C.F.R. §265.173
ADEM Admin. Code r.
335-14-5-.09(4)(a)&(b)
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Record of Decision
Olin Mcintosh OU-2 Site
Table 32. Action-Specific Applicable and Relevant and Appropriate Requirements and To-Be-Considered Guidance
Action
Kc(|iiircmcnls
Prcrcqiiisile
( ilalion
Open, handle and store containers in a manner that will not cause
containers to rupture or leak.
Containers having capacity greater than 30 gallons must not be
stacked over two containers high
ADEM Admin. Code r.
335-14-5-.09(4)(c)
Storage of hazardous
waste in container area
Area must have a containment system designed and operated in
accordance with 40 CFR 264.175(b)(l)-(5).
Storage of RCRA hazardous
waste in containers with free
liquids - applicable
40 C.F.R. § 264.175(a)
ADEM Admin. Code r.
335-14-5-.09(6)(a)
Area must be sloped or otherwise designed and operated to drain
liquid resulting from precipitation, or
Containers must be elevated or otherwise protected from contact
with accumulated liquid.
Storage of RCRA hazardous
waste in containers that do not
contain free liquids (other than
F020, F021, F022, f023,F026 and
F027) - applicable
40 C.F.R. § 264.175(c)(1)
and (2)
ADEM Admin. Code r.
335-14-5-.09(6)(c)(l) and
(2)
Closure of hazardous
waste container storage
with containment
system
At closure, all hazardous waste and hazardous waste residues must
be removed from the containment system. Remaining containers,
liners, bases, and soils containing or contaminated with hazardous
waste and hazardous waste residues must be decontaminated or
removed.
[Comment: At closure, as throughout the operating period, unless
the owner or operator can demonstrate in accordance with40 CFR
261.3(d) of this chapter that the solid waste removed from the
containment system is not a hazardous waste, the owner or
operator becomes a generator of hazardous waste and must
manage it in accordance with all applicable requirements of parts
262 through 266 of this chapter].
Storage of RCRA hazardous
waste in containers in a unit with
a containment system
applicable
40 C.F.R. §264.178
ADEM Admin. Code r.
335-14-5-.09(9)(a)
11 (isle Disposal — Primary Wastes (e.^.. contaminated sediments and suit samples and Secondary Wastes (e.g., decon wastewaters)
Disposal of RCRA
hazardous waste in an
off-site land-based unit
May be land disposed if it meets the requirements in the table
"Treatment Standards for Hazardous Waste" at 40 C.F.R. 268.40
before land disposal.
Land disposal, as defined in 40
C.F.R. 268.2, of restricted RCRA
waste - applicable
40 C.F.R. § 268.40(a)
ADEM Admin. Code r.
33-14-9-.04
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Record of Decision
Olin Mcintosh OU-2 Site
Table 32. Action-Specific Applicable and Relevant and Appropriate Requirements and To-Be-Considered Guidance
Action
Kc(|iiircmcnls
Prcrcqiiisile
( ilalion
All underlying hazardous coiibULueiib |a^ defined in4u C.l'.R.
268.2(i)] must meet the Universal Treatment Standards, found in 40
C.F.R. 268.48 Table UTS prior to land disposal
Land dibpo^al of reminded RCRA
characteristic wastes (D001 -
D043) that are not managed in a
wastewater treatment system that
is regulated under the CWA, that
is CWA equivalent, or that is
injected into a Class I
nonhazardous injection well -
applicable
40 C.l'.R. £ 2o8.40(ej
ADEM Admin. Code r.
33-14-9-.04
Disposal of RCRA -
hazardous waste soil in
an off-site land-based
unit
Must be treated according to the alternative treatment standards of
40 C.F.R. 268.49(c) or according to the UTSs specified in 40
C.F.R. 268.48 applicable to the listed and/or characteristic waste
contaminating the soil prior to land disposal.
Land disposal, as defined in 40
C.F.R. 268.2, of restricted
hazardous soils - applicable
40 C.F.R. § 268.49(b)
ADEM Admin. Code r.
33-14-9-.04(9)
Disposal of RCRA
characteristic
wastewaters in an
NPDES permitted
WWTU
Are not prohibited, if the wastes are managed in a treatment
system which subsequently discharges to waters of the U.S.
pursuant to a permit issued under 402 the CWA (i.e., NPDES
permitted), unless the wastes are subject to a specified method of
treatment other than DEACT in 40 C.F.R. 268.40, or are D003
reactive cyanide.
Land disposal of RCRA restricted
hazardous wastewaters that
hazardous only because they
exhibit a characteristic and are not
otherwise prohibited under 40
C.F.R. 268 - applicable
40 C.F.R. 268.1(c)(4)(i)
ADEM Admin. Code r.
33-14-9-.01
Transport and
conveyance of collected
RCRA wastewater to
WWTU located on the
facility
Any dedicated tank systems, conveyance systems, and ancillary
equipment used to treat, store or convey wastewater to an on-site
NPDES-permitted wastewater treatment facility are exempt from
the requirements of RCRA Subtitle C standards.
On-site wastewater treatment unit
(as defined in 40 C.F.R. 260.10)
subject to regulation under § 402
or § 307(b) of the CWA (i.e.,
NPDES-permitted) that manages
hazardous wastewaters -
applicable.
40 C.F.R. 264.1(g)(6)
Disposal of RCRA
characteristic
wastewaters in a POTW
Are not prohibited, if the wastes are treated for purposes of the
pretreatment requirements of Section 307 of the CWA, unless the
wastes are subject to a specified method of treatment other than
DEACT in 40 C.F.R. 268.40, or are D003 reactive cyanide.
Land disposal of hazardous
wastewaters that hazardous only
because they exhibit a
characteristic and are not
otherwise prohibited under 40
C.F.R. 268 - applicable
40 C.F.R. §268.l(c)(4)(ii)
ADEM Admin. Code r.
33-14-9-.01
Transportation of Wastes
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Olin Mcintosh OU-2 Site
Table 32. Action-Specific Applicable and Relevant and Appropriate Requirements and To-Be-Considered Guidance
Action
Kc(|iiircmcnls
Prcrcqiiisile
( ilalion
Transportation of
hazardous materials
Shall be subject to and must comply with all applicable provisions
of the HMTA and HMR at 49 C.F.R. §§ 171-180 related to
marking, labeling, placarding, packaging, emergency response,
etc.
Any person who, under contract
with a department or agency of
the federal government, transports
"in commerce," or causes to be
transported or shipped, a
hazardous material - applicable
49 C.F.R. § 171.1(c)
Transportation of
hazardous waste off-
site
Must comply with the generator standards of Part 262 including 40
C.F.R. §§ 262.20-23 for manifesting, Sect. 262.30 for packaging,
Sect. 262.31 for labeling, Sect. 262.32 for marking, Sect. 262.33
for placarding,
Preparation and initiation of
shipment of hazardous waste off-
site - applicable
40 C.F.R. § 262.10(h);
ADEM Admin. Code r.
335-14-3- 03(1) - (4)
A generator who transports, or offers for transportation, hazardous
waste for off-site treatment, storage, or disposal, or a treatment,
storage, and disposal facility who offers for transportation a
rejected hazardous waste load, must prepare a Manifest (OMB
control number 2050-0039) on EPA Form 8700-22, and, if
necessary, EPA Form 8700-22A, according to the instructions in
335-14-3-Appendix I.
ADEM Admin. Code r.
335-14-3-.02(l)(a)
Transportation of
hazardous waste on-
site
The generator manifesting requirements of 40 C.F.R.
262.20-262.32(b) do not apply. Generator or transporter must
comply with the requirements set forth in 40 C.F.R. 263.30 and
263.31 in the event of a discharge of hazardous waste on a private
or public right-of-way.
Transportation of hazardous
wastes on a public or private
right-of-way within or along the
border of contiguous property
under the control of the same
person, even if such contiguous
property is divided by a public or
private right-of-way -
applicable
40 C.F.R. § 262.20(f)
Transportation of
samples (i.e. soil,
sediments and
wastewaters)
Are not subject to any requirements of 40 C.F.R. Parts 261 through
268 or 270 when:
• the sample is being transported to a laboratory for the purpose
of testing; or
• the sample is being transported back to the sample collector
after testing.
• the sample is being stored by sample collector before transport
to a lab for testing
Samples of solid waste or a
sample of water, soil for purpose
of conducting testing to determine
its characteristics or composition
- applicable
40 C.F.R. §
261,4(d)(l)(i)—(iii)
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Olin Mcintosh OU-2 Site
Table 32. Action-Specific Applicable and Relevant and Appropriate Requirements and To-Be-Considered Guidance
Action
Kcqiiircmenls
Prcrcqiiisile
( ilalion
In order to qualify for the exemption in paragraphs (d)(l)(i) and
(ii), a sample collector shipping samples to a laboratory must:
• Comply with U.S. DOT, U.S. Postal Service, or any other
applicable shipping requirements
• Assure that the information provided in (1) thru (5) of this
section accompanies the sample.
• Package the sample so that it does not leak, spill, or vaporize
from its packaging.
40 C.F.R. §
261.4(d)(2)(i)(A) and (B)
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Olin Mcintosh OU-2 Site
Table 33. Location-Specific Applicable and Relevant and Appropriate Requirements and To-Be Considered Guidance (TBC)
l.ncalion
Requirements
Prerequisite
Citation
I'loodplains
Presence of floodplain,
designated as such on a map
Shall take action to reduce the risk of flood loss, to
minimize the impact of floods on human safety, health
and welfare, and to restore and preserve the natural and
beneficial values served by floodplains.
Federal actions that involve
potential impacts to, or take
place within, floodplains -
TBC
Executive Order 11988 -
Floodplain Management
Section 1. Floodplain
Management
Shall consider alternatives to avoid, to the extent
possible, adverse effects and incompatible
development in the floodplain. Design or modify its
action in order to minimize potential harm to or
within the floodplain
Executive Order 11988
Section 2.(a)(2) Floodplain
Management
Presence of floodplain,
designated as such on a map
If there is no practicable alternative to locating in or
affecting the floodplain, the potential harm to the
floodplain shall be minimized.
The natural and beneficial values of floodplains shall
be restored and preserved.
Federal actions that involve
potential impacts to, or take
place within, floodplains -
relevant and appropriate
40 C.F.R. Part 6, App. A, §
6(a)(5)
Endangered and/or Threatened Species
Presence of federally
endangered or threatened
species, as designated in 50
C.F.R. §§ 17.11 and 17.12 -or-
critical habitat of such species
listed in 50 C.F.R. § 17.95
Actions that jeopardize the existence of a listed species
or results in the destruction or adverse modification of
critical habitat must be avoided or reasonable and
prudent mitigation measures taken.
Action that is likely to
jeopardize fish, wildlife, or
plant species or destroy or
adversely modify critical
habitat— applicable
16 U.S.C. § 1538(a)
ADEM Admin. Code r. 335-13-4-
•01(l)(b)
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Record of Decision
Olin Mcintosh OU-2 Site
Table 33. Location-Specific Applicable and Relevant and Appropriate Requirements and To-Be Considered Guidance (TBC)
l.ncalion
Kc(|iiircmcnls
Piviv(|iiisi(e
( ilalion
Each Federal agency shall, in consultation with and
with the assistance of the Secretary [of DOI], insure
that any action authorized, funded, or carried out by
such agency is not likely to jeopardize the continued
existence of any endangered species or threatened
species or result in the destruction or adverse
modification of habitat of such species which is
determined by [DOI] to be critical.
Actions authorized, funded, or
carried out by any Federal
agency, pursuant to 16 U.S.C.
§ 1536 - relevant and
appropriate
16 U.S.C. § 1536(a)(2); 50 C.F.R.
§§ 402.13(a), 402.14
Migratory Birds
Presence of any migratory bird,
as defined by 50 C.F.R. § 10.13
It shall be unlawful at any time, by any means or in any
manner, to pursue, hunt, take, capture, kill, attempt to
take, capture, or kill, possess, offer for sale, sell, offer
to barter, barter, offer to purchase, purchase, deliver for
shipment, ship, export, import, cause to be shipped,
exported, or imported, deliver for transportation,
transport or cause to be transported, carry or cause to
be carried, or receive for shipment, transportation,
carriage, or export, any migratory bird, any part, nest,
or eggs of any such bird.
Federal actions that have, or
are likely to have, a
measurable negative effect on
migratory bird populations -
relevant and appropriate
16 U.S.C. § 703(a)
Avoid or minimize, to the extent practicable, adverse
impacts on migratory bird resources.
Federal actions that have, or
are likely to have, a
measurable negative effect on
migratory bird populations -
TBC
Executive Order 13186
Wetlands
Presence of wetlands, as
defined by ADEM Admin.
Code r. 335-8-l-.02(nnn)
Impacts to wetlands shall be mitigated through the
creation of wetlands or the restoration and
enhancement of existing degraded wetlands.
Actions in wetlands -
relevant and appropriate
ADEM Admin. Code r. 335-8-2-
.02(4), 335-8-2-.03(l)
2 of 6
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Record of Decision
Olin Mcintosh OU-2 Site
Table 33. Location-Specific Applicable and Relevant and Appropriate Requirements and To-Be Considered Guidance (TBC)
l.ncalion
Requirements
Prcrcquisile
( ilalion
Presence of wetlands
Shall take action to minimize the destruction, loss or
degradation of wetlands and to preserve and enhance
beneficial values of wetlands.
Federal actions that involve
potential impacts to, or take
place within, wetlands - TBC
Executive Order 11990 -
Protection of Wetlands
Section l.(a)
Shall avoid undertaking construction located in
wetlands unless: (1) there is no practicable alternative
to such construction, and (2) that the proposed action
includes all practicable measures to minimize harm to
wetlands which may result from such use.
Executive Order 11990,
Section 2.(a) Protection of
Wetlands
Coastal Areas
Location encompassing coastal
zone, as defined by 16 U.S.C. §
1453(1)
Each Federal agency activity within or outside the
coastal zone that affects any land or water use or
natural resource of the coastal zone shall be carried out
in a manner which is consistent to the maximum extent
practicable with the enforceable policies of approved
State management programs.
Federal actions within coastal
zones - relevant and
appropriate
16 U.S.C. § 1456(c)(1)(A)
Discharge of Dredge and/or Fill Material into Waters of the United States and/or State of Alabama
Location encompassing aquatic
ecosystem as defined in 40
C.F.R. § 230.3(c)
No discharge of dredged or fill material shall be
permitted if there is a practicable alternative to the
proposed discharge which would have less adverse
impact on the aquatic ecosystem, so long as the
alternative does not have other significant adverse
environmental consequences.
Action that involves discharge
of dredged or fill material into
waters of the United States,
including wetlands - relevant
and appropriate
40 C.F.R. § 230.10(a)
Clean Water Act Regulations -
Section 404(b) Guidelines
3 of 6
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 33. Location-Specific Applicable and Relevant and Appropriate Requirements and To-Be Considered Guidance (TBC)
l.ncalion
Requirements
Prcrcquisile
( ilalion
Location encompassing aquatic
ecosystem as defined in 40
C.F.R. § 230.3(c) con't
No discharge of dredged or fill material shall be
permitted if it:
• Causes or contributes, after consideration of
disposal site dilution and dispersion, to violations
of any applicable State water quality standard;
• Violates any applicable toxic effluent standard or
prohibition under Section 307 of the Clean Water
Act;
• Jeopardizes the continued existence of species
listed as endangered or threatened under the
Endangered Species Act of 1973, or results in the
likelihood of the destruction or adverse
modification of critical habitat;
• Violates any requirement imposed by the Secretary
of Commerce to protect any marine sanctuary
designated under title III of the Marine Protection,
Research, and Sanctuaries Act of 1972.
Action that involves discharge
of dredged or fill material into
waters of the United States,
including wetlands - relevant
and appropriate
40 C.F.R. § 230.10(b)
Clean Water Act Regulations -
Section 404(b) Guidelines
No discharge of dredged or fill material shall be
permitted which will cause or contribute to significant
degradation of the waters of the United States
40 C.F.R. § 230.10(c)
Clean Water Act Regulations -
Section 404(b) Guidelines
No discharge of dredged or fill material shall be
permitted unless appropriate and practicable steps have
been taken which will minimize potential adverse
impacts of the discharge on the aquatic ecosystem.
40 C.F.R. § 230.10(d)
Clean Water Act Regulations -
Section 404(b) Guidelines
4 of 6
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Record of Decision
Olin Mcintosh OU-2 Site
Table 33. Location-Specific Applicable and Relevant and Appropriate Requirements and To-Be Considered Guidance (TBC)
l.ncalion
Kc(|iiircmcnls
Prcrcqiiisile
( ilalion
Presence of State waterbottoms
or adjacent wetlands, as
defined by ADEM Admin.
Code r. 335-8-l-.02(a)
Dredging and/or filling of State waterbottoms or
adjacent wetlands may be permitted provided that:
• There will be no dredging or filling in close
proximity to existing submersed grassbeds;
• Dredging, filling or trenching methods and
techniques are such that reasonable assurance is
provided that applicable water quality standards
will be met; and no alternative project site or
design is feasible and the adverse impacts to
coastal resources have been reduced to the greatest
extent practicable.
Dredging and/or filling of a
State waterbottom or adjacent
wetland - relevant and
appropriate
ADEM Admin. Code r. 335-8-2-
.02(l)(c) & (d)
Dredging, filling, or trenching resulting in a temporary
disturbance may be permitted provided that all areas
are returned to preproject elevations and all wetland
areas are revegetated and the requirements of ADEM
Admin. Code r. 335-8-2-.02(l)(b) thru (d) are met.
ADEM Admin. Code r. 335-8-2-
.02(2)
Any fill material placed on State waterbottoms or in
wetlands shall be free to toxic pollutants in toxic
amounts and shall be devoid of sludge and/or solid
waste.
ADEM Admin. Code r. 335-8-2-
.02(5)
The salinity of return waters from dredge disposal sites
shall be similar to that of the receiving waters and
reasonable assurance provided that applicable water
quality standards met.
ADEM Admin. Code r. 335-8-2-
.02(8)
5 of 6
-------
Record of Decision
Olin Mcintosh OU-2 Site
Table 33. Location-Specific Applicable and Relevant and Appropriate Requirements and To-Be Considered Guidance (TBC)
l.ncalion
Kc(|iiircmcnls
Piviv(|iiisi(e
( ilalion
Presence of non-adjacent
wetlands, as defined by ADEM
Admin. Code r. 335-8-1-
,02(nnn)
Dredging or filling of non-adjacent wetlands may be
permitted provided that:
• No alternative project sites or designs which avoid
the dredging or filling are feasible and the adverse
impacts have been reduced to the greatest extent
possible; and
• The non-adjacent wetlands to be dredged or filled
have a limited functional value.
Dredging and/or filling of
non-adjacent wetland -
relevant and appropriate
ADEM Admin. Code r. 335-8—
2-.02(3)
Drainage of Waterbodies
Presence of any stream or other
body of water proposed to be
impounded, diverted,
controlled, or modified for
drainage
Department or agency of the United States, first shall
consult with the United States Fish and Wildlife
Service, Department of the Interior, and with the head
of the agency exercising administration over the
wildlife resources of the particular State wherein the
impoundment, diversion, or other control facility is to
be constructed, with a view to the conservation of
wildlife resources by preventing loss of and damage to
such resources as well as providing for the
development and improvement thereof in connection
with such water-resource development.
Federal actions that propose to
impound, divert, control, or
modify waters of any stream
or body of water greater than
10 acres - relevant and
appropriate
16 U.S.C. § 662(a)
Fish and Wildlife Coordination
Act
ADEM = Alabama Department of Environmental Management
ADPH = Alabama Department of Public Health
ARAR = applicable or relevant and appropriate requirement
AWPCA = Alabama Water Pollution Control Act
C.F.R. = Code of Federal Regulations
CWA = Clean Water Act
DOI = U.S. Department of the Interior
> = greater than
< = less than
> = greater than or equal to
< = less than or equal to
TBC = To Be Considered
U.S.C. =U.S. Code
6 of 6
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FIGURES
NOTICE
Figures are used for reference purposes only. U. S. EPA makes no warranty or
guarantee as to the content (the source is often third party), accuracy, timeliness, or
completeness of any of the figures provided, and assumes no legal responsibility for the
information contained in these figures
-------
Approximate Berm
Flood Gate Location
Legend
Site
Location
/Alabama
Mt
™shington County
&ISU32 MMStel&l*, Q&Sga, Uail&lil, JJ63EBV
l§H 9®JS aafeefeps, snfl S® ©OS to? domnsi^r
Ml
fnUffT33
Figure 1. Oliri Mcintosh OU2 Location Map
-4-
-------
Sanitary
Landfills I
(closed)
IBasinl
Brine Filter
Backwash Pond
I (clean closed)
Stormwater
Pond
Brine Well j
|4 (Closed) 1
Diaphram Cell
Brine Ponds
Brine Well
[5 (Closed)
Diaphram Cell
Brine Ponds
Brine Filter
iBackwash Pond
I (clean closed)
Brine Wetl
«- |2 (Closed)|
Hazardous Waste Drum I
(Flammable) Storage Pad]
(clean closed) I
|Brine Weill
|3 (Closed) I
I Brine Well ¦
|j (Closed) j
3 Brine Well
|6 (Closed) r
Mercury Drum
Storage Pad
(clean closed)
Mercury Cell
Plant Area
|(decomissioned)|
- u
I Strong Brine lAL
Pond
iAsh Ponds
^¦IOViIIOO
-1 ill 1
1 (Inactive)
[]Ash Ponds H
| Ditch |
1 Old Plant 1
¦j* -rf?,
l(CPC) Landfill ¦
I (closed) ^9
Legend
O Brine Wells
11 1 Approximate OU-1 Boundary I
_J Approximate OU-2 Boundary I
2,000
3 Feet I
f Service Layer Credits: Source: Esri. DigitalGlobeTGeoEyeTi-cubed, USDA;USGS.J
¦ AEX. Getmapplng'Aerogrid. IGN, IGP, swlsstopo, and the GIS User Community 1
Figure 2. Operable Unit Locations
-5 -
-------
Figure 3. Olin Mcintosh OU 2 2006 Bathymetric Survey
-6 -
-------
-------
SCALE: NOT TO SCALE
LEGEND
~ PREDOMINANT GROUNDWATER FLOW DIRECTION
I WATER LEVEL
R -Riverine Deposits: These deposits ore of unspecified ages and consist of reworked 01, 02. <
and Tm1 sediments along with river-transported sediment. The sediments consist of predominately (
silty or cloyey sands, silts, and cloys.
Qi -The Upper Clay Unit of the Quaternary Alluvial Sediments: The lithology of this unit is
variable, but is composed primarily of silty/sandy clay; the silt and sand content varies and generally '
increases with depth, {Does not exist throughtout all of 0U-2).
CLAY/SILTY CLAY
pV_ jfl SANDY CLAY
Os
_ -The Alluvial Aquifer Unit of the Quaternary Alluvial Sediments: The upper zone of the Alluvial
Aquifer is composed primarily of very fine to fine-grained, silty sand. The lower zone of the aquifer
is composed of fine-to-very-coarse sonds containing varying amounts of fine-to-large gravel.
FINE TO COARSE SAND
Tm,
" j —The Miocene Confining unit: This unit is dominontly clay, with various amounts of
discontinuous sand, silt, or sometimes fine grovel.
NON FLOOD CONDITIONS WITH RIVER
AND BASIN AT 3 FEET NAVD
CONCEPTUAL N0RTO-S0UTH CROSS-SECTION
Figure 5. Conceptual Cross Section Diagram (North-South)
-------
Figure 6. Geologic Cross-Section (West-East) of Olin Basin (top) and
Section Locations (Bottom)
-9 -
-------
SDCR-12
SDCR-5
SDCR-4]
SDCR-7
SDCR-3
BA -MW4Bi
BA-MW4g
¦IN LE TjH
!cha¥meij
[SDCR-131
| Legend
C 2009 Sediment Core Locations
© Micro-Well (MW) Location
Piezometer (PZ>Location
|SDCR-9|
[SDCR-101
[SDCR-11I
1SDCR-8I
ISDCR-61
SDCR-1
o
i=S*3S5QSs
SDCR-2
|Souree: u SDA/FSA - A&ra; Fftotograpivf Fieifl offics^acoe^
Figure 7. Micro-well, Piezometer, and 2009 Sediment Core Locations
-10-
-------
PRIMARY
SOURCES
PRIMARY
RELEASE
MECHANISM
SECONDARY
SOURCES
SECONDARY
RELEASE
MECHANISM
BA5 N/ROUND
POND (SURFACE
Wft~ER AND
SED MEN'S)
D'REC""
ccrr^c'
\
->
OVERFLOW
VOLATILIZATION
FLCCuPLA n
SURFACE,'
SED MEN-
3E
FUGITIVE DUSIS/
IVOLATIL1ZATION
UP'AKE/
ASS r,1 LA~.CN
D REC
CON~AC
RUNOFF/GATE
EFFLUEN"
FiLLOU"'' DUS
5E~LEMEfr/
SURFACE Wa~ERl
MIGRATION
PATHWAY/
EXPOSURE MEDIA
EXPOSURE ROUTE
Pft'.-'N/KUUNUFUNU
SURFACE WAIR/
SEC-MEN-
AIR
AQUATIC BIOTA
TCMB GBEER VER
SURFACE'A A~ER
AIR
VEGETATION
IAS N FLC3DPLA N
SURFACESG U
SED MEN~
fNFILTWION/
GROUNDWATER
D REC-
GROUNDWATER
PERCOLATION
~
CQNTAC_
j*
RECEPTORS
a
1 'I
'C .XI
t;
JE S 5
E
2 E
f
S
E
H "S
m «
fl
| DERMhL
•
o
o
0
•
! INGESTION
•
# 1 «
o
•
•
| FCCDCH4JN
1 •
o
•
•
| DERMAL
' INGESTION
1 FCCDCHAIN
| DERMAL
o
o
j INGESTION
•
•
#
•
•
| FOCCCHAIH
•
#
•
#
| DERMAL
•
o
o
o
o
! INGESTION
•
•
•
•
0
| FGCCCH-JIM
•
•
•
o
I DERMAL
X
X
X
X
X
X
X
i INGESTION
| FCOCCHAIh
X
X
X
X
X
X
X
X
X
X
X
X
X
X
| IMHALATION
•
! INGESTION
| FCCDCHAIM
| DERMAL
o
o
! INGESTION
•
#
| FCCDCHAIN
•
•
| DERMAL
X
X
X
X
X
X
X
i INGESTION
X
X
X
X
X
X
X
1 FCCDCHAIN
X
X
X
X
X
X
X
LEGEND'
• Exposure pathway quant tat1,e y eva uated
O Exposure pathway qua tat ¦¦ e'ye«a uated
x Exposure pathway not eva uated
Blank boxes Exposure path';,/ay neenp ete or neg igible
* Human: i respasser (adult and adolescent)
Figure 8. Site Conceptual Exposure Model OU-2
-ii-
-------
NORTH SOUTH
GEOLOGIC
CROSS SECTION
NORTH-SOUTH
Figure 9. Conceptual Cross Section Diagram (North-South) with Sediment Cores
-12-
-------
aXJ2B-FPSS6mO:
["OU 2B-FPSB1 -1071 -2'
[bU2B-FPSS4j10]
Mo!2M
[OU 2B-FP.SB1 ^10^2^'
¦arojs^Mi
[OU2BjFP.5B3l10jD-1|
HMTO 2 TJJMfll
[OU2B'-FPSB1;10^121
rOU2B'-FPSB3TlO'l:2l
[OU2B'-FPSB3llO:2-6]
H'Q;0Ng
IRQNDI
ro02B'-FPSB3llOyi2l
[QU2B-FPSS3TTo]
wmttewmm
[OU 2 B-FP SS7 '10]
[Cm2B'rFP.SS2?o!
'j
[bU2B-FPSS5£l0j
[OU2B-FPSB2-1Q-D£l
[QU2B-FPSB2^10;1-2i
IOU2B-FPSB2-10-2^6]
fcQ2B^FPSB?10yi?
[QU2B-FPSS10-101
[OU2B':FPSB4-10:i-2
[CHJ2B:FPSB4^ 0-2^6]
BWSIISi
'OU 2B-FPSS11 -10]
[OU2B;FPSB5 j0f2jB'
[OU2B-FPSS12-10]
¦INLIE.JlM
pHWNNEll
[QU2B-FPSSt4:10]
;OU2B-FPSB67iO^I2]
¦Mflffo.'i 7JMM
(g) 2010 Inundated Floodplain Soil (Sediment) Sample Locatioi
O 2010 Floodplain Soil Sample Location
¦ « ¦ Approximate 6' Water Elevation
Notes:
Results are in milligrams per kilogram (mgtog)
FPSB : Soil Boring Location
(intervals =0-1 inch. 1-2 inches, 2-6 inches, 6-12 inches)
FPSS : Surficsal Sod (0-1 inch) Location
J ; Estimated Concentration
Floodplain Soil Mercury Results
Figure 10. Locations of Mercury Samples in Floodplain Soil
-13 -
-------
Figure 11. Locations of Methylmercury Samples in Floodplain Soil
|Legend
O 2010 Floodplain Soil Sample Location |
— — ¦ Approximate 6' Wa'er Elevation
Notes:
Results are in milligrams per kilogram
OU2B-FPSB# 10-0-1 (0-1 inch interval)
OU2B-FPSB# 10-0-2 (1-2 inch interval)
-14-
-------
ROUND,
IKONDJ
BWSIN
[OU2B-FPSS15-101
INIiEJs
rasigwi
[OU 2 B -F P SSI4 0]
¦¦¦0 275'JJM
Legend
(§) 2010 Inundated Fioodplain Soil (Sediment) Sample Location (0-1 inch)
' 2010 Fioodplain Soil Sample Location (0-1 inch)
- - - Approximate 6' Water Elevation
Fioodplain Soil Hexachlorbbenzene Results
Figure 12. Locations of HCB Samples in Fioodplain Soil
-15 -
-------
[OU 2B-F PjSS6?0]
|K0*216TJBH
[CHJ2B-FRSBlIl0T0ll
[QU2B^FPSB3I1Q^11
R'0;iHND,
lEONDl
[OU 28-F PSST^TO]
HH0]0553jHH
rOU2B^P.S"S9?Q]
¦¦ooiMja
[OU 2B;FfjSS 10^10]
¦HaobVOoHl
iBWSIN
[gj2B^FPSS1lIlO]
HMf0*035|lMi
[QU2B^FPS"S"t"2Tl"0]
HV0"00558llifl
¦IN HEM
ihilNNEJ
[OU 2 B;F PSB6^1 O^O^lj
Legend
(#} 2010 Inundated Floodplain Soil (Sediment) Sample Location
O 2010 Floodplain Soil Sample Location
m m m Approximate 6' Water Elevation
Notes:
DDTR totals calculated using zero for non-detected congeners
Results m milligrams per kilogram
FPSB Soil Boring Location (0-1 inch)
FPSS : Surficial So* (0-1 inch) Location
J Estimated Concentration
Floodplain Soil DDTR Results
Figure 13. Locations of DDTR Samples in Floodplain Soil
-16-
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ROUND
POND
R~102CTR-W1
SDCR-12-14.5
B:502NW;11>2
B^5,01NEF24>7
bVoVnW(2'6^I
B-5 01 SVv-26.5 *
B-501SE-25.5 ^
B;502NE^86T2
B^502CTR^88.l7i
Bl5.02SVV£37.9
WOTSEWS]
BASIN
SDCR-11-36.5
B-103NE-29 9j
bVo'3NW:29B
B"1 03CTR!-30.9
B-103S'A^3.&j
B-V03SE^2T21
B-104NE-46"3B
i ft M i Tifc'i #4
|B^10'4NW^6^
LBl! 1
B-202NEf22T5j
B-202NW£1-2T6
r°0.''|i u I ill 'i ¦ ij|i|
B-2'02'CTRj34l
B-202SW5CT
R-?Jn9RF^nTR.J
B-203NE-96T51
i »i ii>7»>'i>M
B;203NW£11"61
> ¦ fi i k ¦ « F ^
BJ203CTR55'1
^03§»2l
SDCR:3£69T5:
SDCR^1-87r4
SDCR-2^5:-1
B-303NE-13.2
B-303NW-14.3
B-3Q3CTR-18.1
B-303SW-7:5^
B-303SE^15Ml
INllETi
CHANNEL?
LefJSfHJ
. E-2S3CT3 Soov't 5*arr«r. Samp* Ara ,-xa wit 'toraxy Czr. amn-jon /pjkrjj
Hg soconeentiatoris ififfi
I IS- a ¦' n >TS*3
u-z: mats
~ | 22 - ZK 1T3 V-J
¦01 «C • **— i' j- *-j
¦U —I - DC ST-J
I 3C - V2 rrjlra
2009 Mercury Isoconeentration Map
Basin and Round Pond MM
•totes:
1-Conteurs on screes at discrete sjnp-fs
i. Eifn p lew snifter M-gln&wUft OU2. For example.
B-202M Eumpi»ld»ril»rl»OU2B^I 2KE
Figure 14. Mercury Isoconcentration Map in 2009: Basin and Round Pond
-17-
-------
ROUND
BOND
R-1O2CTR£OT0O 535;
R-101NE -0.0O584
N W^O .005651
R-101CTR :^0YW59^
R?101SW -t0*"00l45|jj
R-101SE - 070"0"64M
sdTcr?z-5P03O31
B-50 2N ErO 0238
B^50 2N W^pTO 14 7|
V?50 2C t i^oToi 86j
flfSO12SW joTW 375
B*50 2 S E 'foToY'14 ¦
B-501NEP0032SJ
B^50^1N VJW0Q3'52
|bWiCTR^.0Q31
B^JTw -0.0195
B-SoW - 0.00378
B-402 -0.00 381
B-404 - 070257;
B-401 '-0.00286
B-103N Ef- 0.00393'.
B*103HW^0'005,1I24
B-004 - 0.00487
B-204 -0.00469
SBCR-8 - 0.00441
B-DH'-0.00431
B -10 3 SIV -0.00 379
B-103SE@WO374
B-101^0^00 265,
B-106 - 0.00569
B-102 - 0.00462
B-104NE -0.00667
B-104NW -0.00599
B-104CTR -0,00592
B-104SW - 0.0068
B-104SE -0.00613
B-202HE - 0.0034
[ B^202N W^0T0Q2l9M BASIN
B-202CTR -0,00432
B-202SW - 0,00487
B:2«2|fej445 Obj„jbe M,„|
W B-203N W -0.0119
* Br203CTR -0,0115
¦ B^203SWffioi27l
B-20iro;00524
B-205 - 0.0030Z
SDCR-lWb 0-674
B-301 -0.003378
SDCR-2^0,001 27
B-303NE -0.00756 5j
, hfc - ii i i ))¦
B-30 3NW - 0,00634
B-30 3CTR - 0.00445
Bp03SW:-0.003771
B-303SE - O.OOSS™
INLiETj
CHANNEL?
£-201 Cffnooste Seamen: Sa Tip Is toaVssanS Me^/frnerotry Cor>remralSon vtb.Vs/
SQCR-S - neCcWesff med M tr.r3 nervjj ver 0-4." (rTJfcE/
MeHg Isoconcentraticns 2009
¦ 0- 0 002 "ifi'fcs
| 0.002 - 0 004 fTQ.VB
| 0.004- - 0.006 fTS *B
T 0..006 - O.OOS rrfl*B
0.002;
2009 Methy If^rouryjlsoconcentratior\[Map
Basin a n d iRoun*d'RoncTHiHbi
1. Contours based on average of discrete samples
2. Sam pie identifier begins with OU2. For exam pie,
B-2B2NE sample identifier is OU2B-2C2NE.
Figure 15. Methylmercury Isoconcentration Map: Basin and Round Pond
-18-
-------
HCB Historical Concentration Boundaries 1991-1992 flj
¦ 2009 HCB Sediment Sample Location and Results
HRhdI
{;¦
H 1 H " ¦ B
^i
mm jks
HO^HEmUsH
¦¦IBh^an'nei7
0 400 800
?CHANNEHn| #
BHHB • tBffli WM
Legend
HCB: Hexachlorobenzene
wEmm
y ..
HCB Historical Concentration Boundaries
1 mg/kg
25 mg/kg
HniHfifl
>100 mg/kg
5.97 HCB Concentration in mg/kg
^MSoureeTuSDA/FSA^Aerial Photography Field Office^2009"^B
^^¦^wcc^l994'Additional Ecological Studies*of OU-2.\Voiume'1^H
Figure 16. Sediment Sample Locations and HCB Results:
Comparison of 2009 to Historical Results
-19-
-------
1991, 1992 and 1994
DDTr Historical Concentration Boundaries
2009 DDTr/DDTR Sediment Sample Location and Results
round]
[PON DJ
round]
I POND]
BASIN
DOTr< 1 mgf'kg.
DDTR < 5 mg/kg
¦ INLET®
[CH ANN Ell
¦ INLETfl
[pH ANN Ell
Legend
DDTr Historical Concentration Boundaries
5m§.fcg
0.324 Concentration in mcy'kg
Sediment Sample Locations and DDT17DDTR Results
Comparison of 2009 to Historical Results jSK
i»»W9>|gBM9IOlBT'
Figure 17. Sediment Sample Locations and DDTr/DDTR Results
Comparison of 2009 to Historical Results
-20-
-------
[RO.iDNDl
iRQljlDl
Sediment'core^na PorewaterCollection Vocations
BASIN
Legend
INllETi
r :f>e»y Sectioned Core/Porewater Location
CHANNEU
2009 SCoimem Core Locations (Hg Analysis}
HCBAnaiyits m Coarsely Sectioned Cores
DD7R Analysis in Coarsety Sectioned Cores
HW1Q|CS13^ Daung locabcw
SPt P Anatysts in Coarsely Sectioned Core
Feet
Figure 18. Sediment Core and Porewater Sample Collection Locations
-21-
-------
gaiNUEiM
^HgSNEl
Legend
fl ESPP Swtace Watef Sample Loeaiion
2009 Surface Water SampltTLocations
Basin and Round RoncjVHjSj
Figure 19. Surface Water Sample Locations in 2009:
Basin and Round Pond
-22-
-------
¦Mweuiy <0017
lwemjtr.e'cury 0 0CO9O3 JQ
km /Hr : _
I HeiKliSfrtxnim
|Pt-;g- ip«
IMtftWy
-r| .
0.017
B'A'SIN
lODTR
I DOTH
|Pg>c«r.1i
¦INUETJ
[ghR'Rn'eiI
IRQ.UNDI
KR0NDJ
I Terrestnal Vegetation Sample LocatKwi
I - - - Appf&«m»|e 6' Wrier EfeMttlon
IkoIm
IsA No! Analysed
I E stone led concentration
¦ jQ Estimated ccrccntrabcn between the method |
Jdetection l mit and the toparbng lm-»t
800 ^Terrestrial^Vegetation Sampling Locations and Results!
~ Feetr '
Figure 20. Terrestrial Vegetation Sampling Locations and COC
Concentrations
-23-
-------
Figure 21. Insect Sampling Locations and COC
-24-
Concentrations
-------
Receptors
Figure 22. Generalized Food Web Model
-25-
-------
Source: Modified from the December 2009 EPA
Mcintosh Presentation _
Note: Receptors
Comparison to Benchmarks
- Media risk evaluated by comparison to
benchmarks instead of food chain modeling
Figure 23. Site Specific Food Web Model
26
-------
Great Blue Heron, Largemouth Bass
1 mg/kg -12 mg/kg
Recommended RG (+): 1.7 mg/kg
Belted Kingfisher (Conservative Exposure)
-0.043 mg/kg - 2.3 mg/kg
Recommended RG (+); 0.36 mg/kg
Belted Kingfisher (Reasonable Maximum Exposure)
4.4 mg/kg - 20 mg/kg
Recommended RG (+}: 6.9 mg/kg
Pied-Billed Grebe
14 mg/kg -109 mg/kg
Recommended RG (+): 25 mg/kg
Little Blue Heron
1.2 mg/kg - 9 mg/kg
Recommended RG (+): 1.6 mg/kg
Mink
¦ 27 mg/kg
(Value directly calculated from risk
equations; Appendix B of RGO Document)
0 20 40 60 80 100 120
Range of Mercury Remedial Goals for Sediment (mg/kg)
+ Indicates the Remedial Goal for the receptor using the combined forage fish dataset.
Figure 24. Mercury Target Sediment Concentrations Protective of Receptor Based on
Risk from Forage and Predatory Fish
-27-
-------
Great Blue Heron
+ 0.3 mg/kg - 0.35mg/kg
Recommended RG (+): 0.32 mg/kg
Belted Kingfisher (Conservative Exposure)
0.28 mg/kg - 0.38 mg/kg
Recommended RG (+): 0.33 mg/kg
Belted Kingfisher (Reasonable Maximum Exposure)
0.69 mg/kg -1.19 mg/kg
Recommended RG (+): 0.91 mg/kg
+
Pied-Billed Grebe
0.37 mg/kg -1.2 mg/kg
Recommended RG (+): 0.66 mg/kg
Little Blue Heron
0.48 mg/kg - 0.71 mg/kg
Recommended RG (+): 0.58 mg/kg
* Predatory Fish * Forage Fish
Recommended RG: Recommended RG:
0.21 mg/kg 0.63 mg/kg
0 0.5 1 1.5 2 2.5 3
Range of DDTR Remedial Goals for Sediment (mg/kg)
+ Indicates the Remedial Goal for the receptor using the combined forage fish dataset (forage fish + predatory fish for Great Blue Heron).
Vindicates the sediment Remedial Goal for fish based on bioaccumulation into fish tissue
Figure 25. DDTR Target Sediment Concentrations Protective of Receptor Based on
Risk from Forage and Predatory Fish
-28-
-------
Diet: Flying Insects, Crawling Insects, and
Spiders, 1994 Data Included
Recommended RG: 1.1 mg/kg
Diet: Flying Insects, Crawling Insects, and
Spiders, 1994 Data Excluded
Recommended RG: 0.94 mg/kg
Diet: Spiders
Recommended RG: 1.3 mg/kg
Diet: Flying Insects
Recommended RG: 0.54 mg/kg
Diet: Crawling Insects
Recommended RG: 1.9 mg/kg
Diet: Crawling Insects & Spiders
Recommended RG: 1.7 mg/kg
0.2
0.4
0.6 0.8 1 1.2 1.4 1.6
Range of Mercury Remedial Goals for Flood Plain Soil (mg/kg)
1.8
Note: Values represent NOAEL, LOAEL, and geometricmean RemedialGoals.
Figure 26. Mercury Target Soil Concentrations Protective of Carolina Wren
-29
2.2
-------
Flying Insects, Crawling Insects, and Spiders, 1994 Included
0.95 mg/kg -1.4 mg/kg
Geometric Mean RG (+): 1.12 mg/kg
Flying Insects, Crawling Insects, and Spiders, 1994 excluded
0.34 mg/kg - 0.5 mg/kg
Geometric Mean RG (+): 0.41 mg/kg
Flying Insects
0.14 mg/kg - 0.22 mg/kg
Geometric Mean RG (+): 0.18 mg/kg
Crawling Insects
0.72 mg/kg -1.04 mg/kg
Geometric Mean RG (+): 0.86mg/kg
Crawling Insects and Spiders
0.49 mg/kg - 0.77 mg/kg
Recommended RG (+): 0.63 mg/kg
0.5 1
Range of DDTR Remedial Goals for Flood Plain Soil (mg/kg)
1.5
+ Indicatesthe geometricmean RemedialGoal for the invertebrate grouping.
Figure 27. DDTR Target Soil Concentrations Protective of the Carolina Wren
-30-
-------
Forage Fish Tissue RG Based on
+ Protection of Piscivorous Birds
RG (+): 0.20 mg/kg
Forage Fish Tissue RG Based on
Protection of Forage Fish
RG (+}: 0.28 mg/kg
Predatory Fish RG Based on
Protection of Predatory Fish
RG (+): 0.28 mg/kg
Predatory Fish RG Based on
Protection of Piscivorous Birds
RG (+): 0.43 mg/kg
+
Predatory Fish Filet RG Based on
Protection of Human Health
RG (+): 0.3 mg/kg
0 0.2 0.4 0.6 0.8 1
Mercury Remedial Goals for Fish Tissue (mg/kg)
Figure 28. Mercury Target Fish Concentrations Protective of Fish,
Piscivorous Birds, and Humans
-31-
-------
4
Forage Fish Tissue RG Based on
Protection of Predatory Fish
RG (+): 0.23 mg/kg
Forage Fish Tissue RG Based on
Protection of Piscivorous Birds
(Little Blue Heron)
RG (+): 0.43 mg/kg
Forage Fish RG Based on
Protection of Piscivorous Birds
(Great Blue Heron)
RG (+): 0.52 mg/kg
Predatory Fish RG Based on
Protection of Predatory Fish +
RG (+): 0.64 mg/kg
0 0.2 0.4 0.6 0.8 1
DDTR Remedial Goals for Fish Tissue (mg/kg)
Figure 29. DDTR Target Fish Concentrations Protective of Fish and Piscivorous Birds
-32-
-------
ROUND
POND
Ri102CTRi147ll
'SDCR-12-14.5
,BT502NWI1,121
W02NE$6^
b502CTRW7J
B-501NEW7J
[^blNW-2'6^|
rB-501^fR:24^
[b^501'sW^26^|
[$5ViSE;25T5l
IB-502SW^37:9
B-502SEW§1
[SDCRi11p6T5!
BASIN
B-103NE-28.9..
^l'03NW^29M
W03Swh2^
fB^I 03SE t32T2M
W03CTRt30"9
:SDCRT8£25j
BfO 04£38>3 i
05i23Tl]
[ B^20 2 NE ;22Jb 1
B-20'2'CTR24|
'B-7o"2Sw5^41
^02^6^5]
fBjl 04NWj6T8J
B^04CT'Fg77;6
WQ4Swj47^|
RTl*^Vc51"7A7«
B^03NEg6T5l
:Bffio3CTRg^
BgV3Swj3^S|
W03SE^03«
B-205-7*ll
:SDCR-1-*87T4]
:SDCRi3W5j
•SDCR-2?5:1]
B-302-2.01
B-303NE-13.2
tB-303NW-14.8
B-303CTR-J8.1
B-303SW-7.5j|
B-303SE-15^1
; ane MercuryCoocenTaTtn /pxa&gi
.Mercuryjjtemedial Fobtpri nt for^C appi rig - AIternative s)2A^n d[2C;
nttMii.6 to 10 7 mg/kg Mercury) 1
Legend
\ 5-201 CarnooSK SeSVwr.
0 B-I02CTS OiKiwe Same!
J SQDR-8 F**C«C -«300F1 WettWKf Mercwy .** era b* Over 0-**
Sasr are ftco-ia Pons
10.7 ""IJ.Ka
Hg Isoconcentrations 2009
1 I 0.13- 10
~ 10-20 mo.tB
i I 20- ic-ns*e
¦[ 30- 40rn(f*B
40 - SO 1J V|5
50 - 70 "IB ICS
70 - 90 ~iS Vi
90- H0rr®,*B
¦j 110 -130 n$*(j
I 130 - 150' "£ KB
~ 150- 170 T»*a
I I 170- 1SG r-e-fcB
I 1» - 3C0 ~»KB
INIlETj
fCHANNEfl
Notes:
1. Contours based on average of discrete samples. I
2. Sample identifier begins with OU2. For example,
1 300- *00 m&VB B-202NE sample identifier is OU2B-202NE.
| | 400 - wo
150 300 450 600
Feet I
Figure 30. Mercury Remedial Footprint for
Capping Alternatives 2A and 2C (> 1.6 to 10.7 mg/kg Mercury)
-33 -
-------
[ROUND]
ygofipi
BASIN
[INllETi
Legend
0- 1 mg&g
101 3 nvgAg
JOt 5myVg
5 01 ¦ 7.6 momg
76-89
^»6WHCBJ_socontour Map With MercuryJJ
Remedial Footprint'('">X1 T6 to^i0.7jmcirfkef Mercury)
B»M> aiW Round s*ond
- Mertuiy R»m«oa' Fcotpr.r* zl PRO of 1 6 m^*g
- M#rewy Rem*ffl»i Footprint at PRQ »f 10 7 mg*g
i Concentrations 2009 (PRG = 7.6 mg/kg)
1 Sample identifier begin* witti OU2 For example. I
B -4Q2C sample Identifier ¦¦ OU28 SEO-402C 03
2.1991 and 1992 Rl data show concentration ol
<7.6 mg Vg at southern edge ol basin.
@ 2009 HCB Sedment Sample locaton and R«u8»
Figure 31. HCB (2009) Isocontour Map with Mercury Remedial Footprint
(>1.6 to 10.7 mg/kg Mercury)
-34-
-------
gQ.UNDj
ingoNDg
DDTR
3DCR9
)UjB;SEDg02^0^
DDTr =0.019
ODTR =0 060
KiUI2B?SED?l03DGTff91
I DDTr-b:138
MmDTR:|=6 305
BASIN
OU2B-SED-203DC-09
) DDTr =0 40
)U2BiSEb-303DC'-b9
DDT. = 0739
INLEfjM
jgWgNNEll
Legend
@ 2009 DDTR Surfiefal Sediment (0-4") Sample Location and Results
Basin and Round Pond
Mercury Remedial Footprint at PRG of 1.6 mg/kg
Mercury Remedial Footprint at PRG 10.7 mg/kg
DDTR Concentrations 2009 (PRG = 3 mg/kg)
n il Notes:
1. Sample identifier begins with OU2. For example.
1-15 mg/kg B-402C sample Identifier Is OU2B-SED-402C-09.
2. Recommended PRG is 3.0 mg/kg. Maximum DDTR in
surficlal sediment is 2-7 mg/kg.
3. 2009 sediment cores are included; however, the interval
They are included here as a possible approximation.
2.5 - 2.7 mg/kg (Maximum DDTR)
1.5 -2 mg/kg
2.1 -2.5 mg/kg
B2009 DDTR Isocontour,Map.With MercuryM
Remedial F^ootprint"(?T1 f6~toTl 0 ¦ 7i m g /k"g*Mercury)
Figure 32. DDTR (2009) Isocontour Map with Mercury Remedial
Footprint (>1.6 to 10.7 mg/kg Mercury)
-35 -
-------
Legend
P>UND
I eo n 51
tof be,Capped
Iliri-situnfiiS
BASIN1
Remedial Footprint for Capping Alternative 2B
3GK7* (In-Situ I Dry Capping'HytjricI) J
Mercury Remedial Footprint at PRG of 1.6 mg,'kg
- Mercury Remedial Footprint at PRG of 10 7 mg/Vg
Area to be capped In Dry
I Area to be Capped in-sttu
2006 Bathynvefric Survey (Elevations in NAVD 88)
MnjetM
JghhnneuB
|0 200 400 600 800
Feetl
Figure 33. Remedial Footprint for Capping Alternative 2B
(In-Situ/Dry Capping Hybrid)
-36-
-------
ROUND
POND
R-102CTFK1471]
R-101NE-24.8
rJioYnw^ii
R101CTR-21W
R10'l'sW-32^il
^R-10TsE-22*8B
1K502NW£li2l
K502NE5'6'2l
B-501NEf24yl
'B-5b'lNw5S2l
E-f 01CTR-24.9'
'BgQISV^g^
K»1sT~2575J
B-502CJFm77j
^^2sw^7g|
B5'02SE{9Ci^I
Bl401-24:6'
,Bl403£35<7j
B^04-'1W
6-^02-27:1
B-103ME-28.9:
B-T03NWg9M
[B^l'L0L3CTRT3yg
;B-l'03SW^2'5j
Bii*03SE$2T2l
SDCR-8-25
B-004-38.3
BlioiraJj
E-102-33.1
B-106-38?7j
KiogSTil
.K104NE563,
B5(KNEj2Z5j
K202NVPi2^
- ¦» 1 1 H J
B[202CJRj34l
"fe02Swffiiffl
'B-202SE-m5j
Bg,°4NWg6X|
motej"R;7,7y
BW4SW57M
BASIN
[B^03NEW5J
[S203CfR55^
B^o'3SW^84Q|
BW3SEW3B
[SDCRiSSTS;
B-205-7.1
Bg03NWlj47g
b503CTR?8^
| Bj3Q 3SW^7-^1
B-BOSSEMMi
SDCR-2-5.11
B-304-JW
Sample Ana i'ss ana Mercury CoeKerwaBon Anodes)
Legend
A B-201 Compose
r^\
\ J B-20ICTR 0*3** Seo
Core .ocasoo W«B»ee9H«rari Ay erase Over o--*" 'jn^'lcs)
Deeper Poraon a! :fse Sas-^ Or Deeser Area o1 Drees nc
5a»s-i ana Roj-io Pond
< 1.6 rns*fl Mercury =RO
-e 10.7 fronts M er cury PRO
Hg Isoconcentratk>ns2009
0.13 -10 PfiBltB
I I 10-10 nv*0
a - 30 nj.lcs
30- *0 rg.fcs
¦iO- 50 rr®,*B
SO - 70 natS
70- SO n«ftg
90- 110 ms,*B
110- 130 rro *B
130 -150 Rig*B
I I 150 - 170 ttb>1cb
~ |Jo(es:
I 1190 '500 "1ff1C3 1. Contours based on average of discrete samples.
300 - *00 ma>«cB 2- Sample identtfier begins withOU2. For example,
~
4C0 - 44C n&lcs
B-202NE sample identifier is QU2B-202ME.
150 300 450 600
Feet]
Figure 34. Remedial Footprint for Dredging: 0-1 Foot Interval
-37-
-------
SDCR-iJ
Dtpth Cft'i
IS
1
0.30
2
0.27
3
0.17
4
0.092
5
SDCR-12
Dfpth
23
1
16
2
»0
3
64 | 4
17
5
1.7
6
0.69
7
0.43
8
0.11
9
1
Depth (fti
,21
*
*
3
115
4
22
5
0.17
6
sDcn-i
Depth (ft)
20
I
18
2
19
3
300
4
5
120
6
9
7
1
8
0.55
9
Isixx 6
Depth
-------
iixs IJ
Depth (ft)
IS
1
0.30
2
0.27
3
0.17
4
0.092
5
SDCR 12
Dfpfli (ft,I
I
33
0.38
2
0.68
3
0.17
•1
0.09*1
5
0.088
6
SDCR 9
Off*}) (ft)
120
1
170
2
15
3
3.1
4
0.25
5
0.14
6
SDCR 4
Drpth (ft)
23
1
16
2
230
3
64 | 4
17
5
1.7
6
0.69
7
0.43
8
0.11
9
SlXR-1
Depth (ft.'
121
1
30
2
52 | 3
115
4
22
5
0.17
6
SDCR - 5
Depth (ft)
20
1
18
2
19
3
300
4
96 | 5
120
6
9
7
1
8
0.55
9
SDCR-8
Depth (ft)
23
1
27
2
24
3
15
4
5
[ 440
6
7
8
1 230
9
1 170
10
11
SDCR 10
Depth (ft)
19
1
25
2
24
3
30
4
2.6
5
0.35
6
<16 mg/Kg
10 7 fflg/Kg
NMIS
SCOH ¦ » |C0f») Mmou*
OonetnMMM in
Depth. Depth of Sediment
|SDCR !!
Depth (ft*
1
23
2
0.13
3
1.3
4
0.066
5
| 6 20 mg^
I | 20 - 30 m^na
I I 30 40 vnylq
-10 - SO irigtcg
£0 - 70 mg/Vg
70 90 rngj}
~~1 300 400
1 400 - 440 mO'tv
|sDCR-e
Depth (t)
«
'
1 «
2
1.5
3
1.7
4
0.64
5
0.49
6
0.060
7
0.073
8
0
300
600
SDCR-2
19
Depth (fit
1
19
421 3
18
4
0.17
5
0.38
6
0.070
7
0.060
8
0.057
9
0.055
10
StVR - T |!Vpih (fi i
88 | 1
2.6
2
0.55
3
0.16
4
0.076
5
0.018
6
0.063
7
0.059
8
SDCR -J
Depth (B)
34
1
2.8
2
0.53
3
0.50
4
0.13
5
0.19
6
0.13
7
0.07
8
0.074
9
0.14
10
Remedial Footprint for Dredging (Alternative 3)
2 - 3 Foot Interval
Figure 36. Remedial Footprint for Dredging (Alternative 3):
2-3 Foot Interval
-39-
-------
SDCR 1?
Depth (ft,
18
1
0.30
2
0.27
3
0.17
4
0.092
5
SDCR 12
Drpiti (ft)
33
1
0.38
2
0.68
3
0.17
4
0.094
5
0.088
6
|SDCR-9 |Depth (ft)
no ,
170
2
15
3
3.1
4
0.25
5
0.14
6
SDCR-4
Depth (ft)
23
1
16
2
230
3
641 4
17
5
1.7
6
0.69
7
0.43
8
0.11
9
SDCR-I
Depth (ft)
121
1
30
2
3
115
4
22
5
0.17
6
SDCR 5
Depth (ft 1
20
1
18
2
19
3
300
4
5
120
6
9
7
1
8
0.55
9
0
300
600
suck :
Drptb (In
19
1
19
2
3
18
4
0.17
5
0.38
6
0.070
7
0.060
8
0.057
9
0.055
10
SIXR-8
Depth (ft)
23
i
27
2
24
3
15
4
P
5
nn
6
,20
,20
8
230
9
170
10
11
5DCR-10
19
Depth (ft)
1
25
2
24
3
30
4
16
5
0i35
6
< 1 6 mg/kg
<10 7 mg/Kg
Moles
SCOR » (Co»») M «rcw>
Conc«rilr«lwi m mjfiq}
CMftfr D«p*\ or S»am®nf
MlFMt
I—
1
23
2
013
3
1.3
4
0.066
5
~ 6 - 20 mg/kg
I 20 • 30 mp'kfl
I | 30-40m9^
40 • SO rwykg
H 50 • 70 0100(9
70 • 90 mj^kg
90 - 1 tO mg1
-------
Conceptual Sheet Pile Wall Diagram
Legend
Conceptual Sheet Pile Wall
1 foot contour
Area to be
back filled
Basin
Proposed NCDU Location
Figure 38. Conceptual Sheet Pile Wall and Locations
-41-
-------
IBAS1
¦inHem
CflA'N NEil
|Legend
Approximate Area Considered for Confirmation Sampling of Hg, HCB, DDTR|
IEZ3 Approximate Area Considered for Confirmation Sampling of DDTR
EZH Approximate Area Considered for Confirmation Sampling of Hg, HCB
Approximate Remedial Footprint for Cap
^ppfoximatqRemedial Footprtntitorl^apl
-42-
-------
APPENDIX 1: EXPLANATION OF REMEDIAL GOAL DERIVATIONS AND
MODIFICATIONS
-------
Explanation of
Remedial Goal Derivations and Modifications
INTRODUCTION
This Appendix provides technical information for remedial goal (RG)
development for receptors and exposure pathways that were not presented in the
OU-2 Remedial Goal Option (RGO) report for development of remedial goals
(MACTEC 2010b). The information provided in this memorandum updates that
provided in the 2012 RGO report in cases where expanded information was used
to derive cleanup levels (CULs) for the OU-2 ROD. The memorandum
documents RG development or changes for the following topics:
• Derivation of fish-tissue-residue RGs and sediment RGs to protect fish for
mercury and DDTR,
• Derivation of sediment RGs to meet fish fillet TBC criteria for human
health
• Changes to the floodplain-soil RGs to protect insectivorous birds exposed
to DDTR in floodplain soils,
• Changes to the sediment RG for DDTR to protect piscivorous birds
feeding on predatory fish, and
• Modification of DDTR RGs based upon OU-2 total organic carbon (TOC)
concentrations.
Derivation of Fish-tissue-residue RGs to Protect Predatory Fish
The RGO Report for OU-2 (AMEC, 2012) developed remedial goals for a variety
of piscivorous wildlife to reduce their risk from exposure to chemicals of concern
through ingestion of contaminated media. The RGO report did not develop
April 2014
1
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
remedial goals to protect fish from the chemicals of concern they passively
accumulate in their bodies through bioaccumulation. RGs to protect fish can be
expressed as either concentrations in the fish, referred to here as fish-tissue-
residue RGs, or concentrations in the sediment, referred to here as sediment
RGs to protect fish, depending on whether the RG will be compared to the fish
tissue concentration (also referred to as the body burden) or the sediment
concentration. Fish tissue concentrations are normally expressed in wet weight.
Hence the units on the fish-tissue-residue RGs are in terms of wet weight in
contrast to sediment RGs, which are always expressed in terms of
concentrations in sediment in dry weight. Fish-tissue-residue RGs can be
developed to protect wildlife receptors that consume fish, this section however,
pertains to the derivation offish-tissue-residue RGs relative to the assessment
endpoint for protection offish populations.
Fish-tissue-residue RGs to protect fish at OU-2 are based on fish-tissue-residue
effects levels published by Beckvar and others (2005). No site-specific toxicity
testing was performed on OU-2 fish in relation to their body burdens of mercury
or DDTR. Risk to fish was assessed in the OU-2 risk assessment by comparing
fish tissue body burdens to fish-tissue-residue effects levels published in the
literature. The Beckvar et al. paper evaluated paired no-effects and low-effects
tissue residue data derived from experimental studies published in primary
literature. From there they derived protective fish-tissue-residue effects levels for
mercury and DDTR using four analytical methods-simple ranking, empirical
percentiles, tissue threshold-effect levels (t-TELs), and cumulative distribution
functions (CDFs). In their evaluation of the four methods, the authors found that
both the t-TEL and the empirical percentile approach 10th percentile low effects
range (LER) provided reasonable results for fish-tissue-residue effects levels.
EPA used the greater of the t-TEL and the 10th percentile low LER as fish-tissue-
residue RGs to protect fish at OU-2 (Table 1). The selected fish-tissue-residue
RG to protect fish for mercury (0.28 mg/kg wet weight) was based on the 10th
percentile LER for adult fish. The selected fish-tissue-residue RG to protect fish
April 2014
2
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
for DDTR (0.64 mg/kg wet weight) was based on the t-TEL for adult fish. Beckvar
et al. (2005) identified the fish tissue effects levels for DDTR as preliminary,
noting that some of the data used to derive the benchmarks represented
mortality endpoints instead of preferred chronic endpoints, such as reproductive
effects.
Table 1. Fish-tissue-resid
ue Effects Levels (from Beckvar et al., 2005)
10th Percentile LER
t-TEL
(mg/kg wet wt.)
(mg/kg wet wt.)
Hg (adult fish)
0.28
0.21
Hg (early life stage)
NA
NA
DDTR (adult fish)
0.50
0.64
DDTR (early life stage)
0.89
0.70
NA = not applicable. Data were insufficient to derive empirical percentiles or t-TEL.
Shading indicates EPA's choice of the remedial goal to protect fish as a whole-body
concentration.
EPA augmented the fish-tissue-residue effects levels in Beckvar et al. (2005)
with studies of DDTR compiled by EPA Region 10. Region 10 compiled the
studies to support development of a fish-tissue-residue RG to protect fish for the
Portland Harbor Superfund site. The Portland Harbor Superfund site is using a
fish-tissue-residue RG of 0.63 mg/kg to protect fish, based on studies Region 9
compiled from the primary literature. Several of the fish species compiled by
Region 9 reside in the Southeastern U.S. (Table 2). The studies on Southeastern
U.S. species in Table 2 provide additional information on the toxicity of DDTR to
fish that was not reported by Beckvar and others (2005). The studies on these
additional species support EPA's adoption of the 0.64 mg/kg fish-tissue-residue
RG for protection offish. A study by Gakstatter and Weiss (1967) reported DDTR
effects on the behavior of goldfish and bluegill. The behavioral effects
(equilibrium loss and convulsions) are normally not used to develop fish-tissue-
residue effects levels. Region 9 provided evidence to link the behavioral effects
observed in the Gakstatter and Weiss (1967) study to adverse effects at the
population level. The Crawford and Guarino (1976) paper was not used to derive
the Portland Harbor fish-tissue-residue RG for DDTR because it appeared to be
April 2014
3
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
inconsistent in discussion of o,p'-DDT or p,p-DDT and reported egg residues for
only one exposure concentration.
Table 2. Fish-tissue-residue Effects Levels from EPA Region 9 Compilation of
Studies Considered with Emphasis on Southeastern U.S. Species.
Species
Endpoint
Endpoint
Effect
Whole
Body
Cone.,
mg/kg
wet
weight
Final
Whole
Body
Cone.,
mg/kg wet
weight*
Exposure
Route
Duration
Studies
Considered
Carassius
Behavior
Equilibrium
6 hours
Gakstatter
auratus
linked to
loss and
5.1
0.61
water
(32-d
and Weiss
(goldfish)
mortality
convulsions
recovery)
1967
Lepomis
macrochirus
(bluegill)
Behavior
linked to
mortality
Equilibrium
loss and
convulsions
4.2
0.51
water
5 hours
(32-d
Gakstatter
and Weiss
1967
Fundulus
Mortality
25%
Crawford and
heteroclitus
Mortality
5.2
0.63
water
24 hours
Guarino 1976
(killifish)
*An acute to chronic ratio (ACR) was applied to toxicity studies where behavior leading to
mortality or mortality was the test endpoint when the exposure duration was less than 30 days.
The ACR used was 8.3 after Raimondo et al. 2007. Chronic endpoints, such as growth or
reproduction are typically measured in studies having an exposure duration greater than 30 days
and do not require an ACR adjustment.
The DDTR fish-tissue-residue effects levels apply to both forage fish and
predatory fish. However, as illustrated in Figure 1, the concentrations of DDTR in
largemouth bass are approximately three times greater than the concentration of
DDTR in forage fish. Greater body burdens of DDTR in largemouth bass (a
predatory fish) compared to lesser body burdens of DDTR in mosquitofish and
brook silversides is a consequence of biomagnification. On average, the
concentrations of DDTR in largemouth bass tissues are about three times greater
than the concentrations of DDTR in forage fish (Table 3). Hence, forage fish will
need to reduce their body burden of DDTR to approximately 0.23 mg/kg in order
for predatory fish to achieve the fish-tissue-residue RG of 0.64 mg/kg. The
recommended fish-tissue-residue (in forage fish) RG of 0.23 mg/kg for DDTR is
predicted to protect predatory fish.
April 2014
4
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 3. Biomagnification of DDTR in Largemouth Bass and Bluegill
Sunfish from DDTR Concentrations in Mosquitofish or Brook
Silversides.
Largemouth
Bluegill Sunfish
Mosquitofish or
Bass
(mg/kg)
Silversides (mg/kg)
Area/Year
(mg/kg)
NE Basin 1994
12.9
-
4.39
Round Pond
48.12
14.96
-
1994
NE Basin 2001
5.71
-
1.38
NW Basin 2001
19.89
-
1.77
SE Basin 2001
14.37
-
1.27
Round Pond
25.02
10.24
-
2001
N Basin 2010
5.3
1.92
0.93
S Basin 2010
3.13
1.73
1.39
All concentrations in Table 3 are reported in units of mg/kg wet weight.
Figure 1. Concentration of DDTR in Largemouth Bass
_ Versus Concentration in Mosquitofish/Silversides.
s
o
a>
bJD
60
50
cc
H
Q
Q
o
e
o
"¦w
cc
o
u
o
u
ex 40
£ 3°
re ¦
CQ
10
0
2
• z
Bass = 3.1 x forage fish
R2 = 0.754
~ Mosquitofish/Silversides
0
10
15
20
Concentration of DDTR in Gambusia (Mosquitofish) or Silversides,
mg/kg
:igure 1. Concentration of DDTR in Largemouth Bass Versus Concentration in
Mosquitofish/Silversides.
The mercury fish-tissue-residue effects level to protect fish of 0.28 mg/kg (Table
1) applies to both forage fish and predatory fish, and represents the whole body
concentration. A matrix comparing the mercury concentrations in paired
observations of forage fishes and predatory fish revealed a lesser degree of
biomagnification of mercury than observed for DDTR (Table 4). The
April 2014
5
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
concentration of mercury in largemouth bass was on average approximately 2.4
times greater than the concentration of mercury in mosquitofish. The
concentration of mercury in largemouth bass was on average approximately 1.9
times greater than the concentration of mercury in brook silversides.
Table 4. Biomagnification of Mercury in Largemouth Bass from Bluegill
Sunfish, Mosquitofish, and Brook Silversides.
Area/Year
Predatory
Largemouth
Bass
(mg/kg)
Forage Fishes
Bluegill Sunfish
(mg/kg)
Mosquitofish
(mg/kg)
Brook Silversides
(mg/kg)
NE Basin 1991/1994
0.86
-
0.45
-
NE Basin 2001
0.70
-
0.46
-
SE Basin 2001
1.3
-
0.38
-
NW Basin 2001
1.5
-
0.47
-
Round Pond 2001
0.86
-
0.41
-
NE Basin 2008
1.5
0.70
-
0.9
SE Basin 2008
1.5
0.66
-
0.82
NW Basin 2008
1.5
0.68
-
0.82
SW Basin 2008
1.7
0.78
-
0.74
Concentrations in fish are whole-body concentrations in wet weight.
Derivation of Sediment RGs to Protect Predatory Fish
The OU-2 RGO report for development of remedial goals evaluated
bioaccumulation of mercury from sediment to fish using three methods: power
analysis, linear regression, and ratio estimators. Substituting the fish-tissue-
residue RGs for mercury concentrations in either forage fish or predatory fish (y)
into their respective bioaccumulation equations and solving for the sediment
concentration (x), the mercury sediment RGs for protection of predatory fish
range from 0.48 - 6.3 mg/kg (Table 5). Predatory fish are important, because
they have higher concentrations of mercury and DDTR in their bodies by
biomagnification.
April 2014
6
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 5. Range of
Mercury Sediment RGs for Protection of Predatory Fish
Bioaccumulation
Target Fish
Sediment Level at
Equation (from RGO
Level (mg/kg
Target Fish Level
Document)
wet wt.)
(mg/kg dry wt.)
Forage Fish
Power Analysis
y = 0.1646x03904
0.135
0.6
Linear Regression
y = 0.0135x +0.0786
0.135
4.2
Ratio Estimator
y = 0.0236x
0.135
5.7
Predatory Fish
Power Analysis
y = 0.3642x03307
0.28
0.48
Linear Regression
y = 0.0368x + 0.2297
0.28
1.6
Ratio Estimator
y = 0.0441x
0.28
6.3
Notes: x = mercury concentration in sediment
y = mercury concentration in whole body fish tissue
An analysis of DDTR bioaccumulation in forage fish using a combined Olin and
Ciba dataset (Table 6) shows that a simple bioaccumulation factor (BAF) of 1.1
can be derived by pairing sediment and forage fish tissue data from the areas of
fish collection (Figure 2). This simple BAF can be used to back-calculate a
sediment RG for protection offish by dividing the fish-tissue-residue (in forage
fish) RG of 0.23 mg/kg by the BAF of 1.1, yielding a sediment RG for protection
of fish of 0.21 mg/kg DDTR in sediment (dry weight).
Table 6. Paired Forage Fish and Sediment Data Used to Derive DDTR BAF,
Olin and Ciba Data
Gambusia/
Area of Feature,
Location
Silversides Silversides
Sediment
acres
2008
Cypress Swamp
Focus Area
21
43
2010
Cypress Swamp
Focus Area
1.7
2.3
20
2011
Cypress Swamp
Focus Area
3.5
2.3
2001
Round Pond
8.44
6.63
2010
Round Pond
0.8
0.26
4
2011
Round Pond
0.7
0.26
1994
Olin Basin
4.39
3.29
2001
SE Olin Basin
1.31
1.27
2001
NW Olin Basin
2.67
1.77
2001
NE Olin basin
1.42
4.03
2010
Olin Basin
1.14 1.14
0.46
76
April 2014
7
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
oj ^
3 F
V) >
H j^lO
fG \
2 M 8
u- £
o
re .2
s- -M
O CO
b
-------
Explanation of Remedial Goal
Derivations and Modifications
Changes to Floodplain-soil DDTR Remedial Goal for Insectivorous Birds
The RGO report derived RGs forfloodplain soil based on risk to insectivorous
birds, as represented by Carolina wren. Toxicity Reference Values (TRVs) used
to derive RGs for the wren were selected from the information presented in the
EPA Eco-SSL guidance for DDTR (EPA, 2007), and were the same TRVs used
to derive RGs for piscivorus birds at OU-2. The TRVs selected for evaluation of
piscivorous birds were based on analysis of data considering all toxicological
endpoints, including egg-shell thinning. However, egg-shell thinning does not
appear to be an important mechanism for reproductive impairment in terrestrial
birds other than raptors, so use of this as a toxicological endpoint for RG
development for terrestrial songbirds is not appropriate. The Eco-SSL NOAEL
TRV of 0.227 mg/kg-d, which was used at OU-2 to derive the RG for piscivorous
birds, was derived from Table 5.1 of the Eco-SSL guidance (EPA, 2007). The
guidance procedure was to take the geometric mean of the NOAEL values,
which was 4.66 mg/kg-d, and compare it with the lowest LOAEL value for
survival, growth, or reproduction. The lowest LOAEL was 0.281 mg/kg-d from
Carlisle et al. (1986) for eggshell thickness. The NOAEL of 0.227 mg/kg-d (Cecil
et al. 1978) was selected as the highest NOAEL lower than the lowest LOAEL.
For terrestrial birds at OU-2, if eggshell thinning endpoints are not considered,
then the lowest LOAEL less than 4.66 and NOT associated with an eggshell
endpoint would be selected from Table 5.1 in the guidance. The first bounded
reproduction study with a LOAEL less than 4.66 that did not have an eggshell
endpoint, was Davison et al. 1976, who reported mortality in Japanese quail at a
dose of 1.3 mg/kg-d. The NOAEL would then be selected as the highest NOAEL
less than 1.3 mg/kg-d that was not an eggshell study. The study of mortality in
the white-throated sparrow (Mahoney, 1975) reported a NOAEL of 1.04 mg/kg-d.
Therefore, 1.04 mg/kg-d was selected as the NOAEL TRV for insectivorous
terrestrial birds, and 1.3 mg/kg-d was selected as the LOAEL TRV for
insectivorous terrestrial birds at OU-2.
April 2014
9
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Floodplain soil RGs for protection of the Carolina wren were revised based on
use of the updated TRVs using the same equations presented in the RGO
Report. Carolina wren was modeled in the RGO Report using current and
historical insect and spider data in various combinations (see ROD Figure 23).
The floodplain soil RGs for DDTR based on the geometric mean of the NOAEL
and LOAEL ranged from 0.18 mg/kg - 1.12 mg/kg, depending on data used to
represent the Carolina wren's diet. Preferred data for use in OU-2 floodplain is
crawling insects and spiders. Based on the crawling insect and spider data, the
recalculated NOAEL to LOAEL floodplain soil RG range was 0.49 mg/kg - 0.77
mg/kg with a geometric mean of 0.63 mg/kg. Therefore, 0.63 mg/kg in floodplain
soil is the concentration selected as the RG for DDTR at OU-2 to protect the
insectivorous bird.
Changes to DDTR RG for Piscivorous Birds whose Diet Includes Predatory
Fish
The RGO document assumed that forage fish were the predominant exposure
pathway to aquatic-dependent wildlife at OU-2. EPA raised the concern that
DDTR can biomagnify in predatory fish. RGs designed to protect forage fish and
wildlife that feed on smaller fish may not be sufficiently protective of predatory
fish and the wildlife that feed on larger fish, such as the great blue heron, osprey,
and bald eagle. DDTR is known to biomagnify in predatory fish at the top of the
food chain. For greater mathematical precision, and to incorporate the diet of the
great blue heron as including 35% predatory fish, EPA recalculated the sediment
RG for great blue heron using the food chain ingestion assumptions exactly as
presented in the OU-2 ecological risk assessment. Olin measured DDTR in fish
tissue and sediment in 2010. At the time, this data was not available for inclusion
in the risk assessment and RGO reports. Data pairings used to derive the
largemouth bass BSAF, including the 2010 data, are shown in Table 7. The
BSAF for DDTR accumulation in predatory fish uses the data for DDTR
concentrations in largemouth bass collected in 1994, 2001, and 2010. In 1991
April 2014
10
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
whole bodies of largemouth bass were analyzed for DDTr (i.e. 4,4'- congeners of
DDD, DDE, and DDT). In 2001 filets and offal of largemouth bass were analyzed
for DDTR. The concentration of DDTR in whole body fish was as reported in the
RGO Support Sampling Report (URS Corp. 2002). In 2010, whole bodies and
filets of largemouth bass were analyzed for DDTR. The whole body data is
preferred for ecological risk assessments because the biota will utilize the entire
fish in their diets. For DDTr a conversion based on the site-specific data was
used to predict the DDTR concentration based on the ratios of DDTr to DDTR
observed in sediment samples and fish tissue samples. The data for predatory
fish tissue DDTR concentrations and sediment concentrations was paired up by
year and by location within OU-2 (Table 7). Data from the Ciba site investigation
was available for largemouth bass collected from within the Olin Basin in 1991.
This data was obtained from Ciba's BERA and included in Table 7 of the paired
data for DDTR in predatory fish and sediment.
Average concentrations and lipid- and TOC-normalized concentrations were
computed for generating the bioaccumulation plots for DDTR accumulation
predatory fish. In 1991 the concentrations were measured as DDTr in both fish
and sediment. Concentrations of DDTr were converted to DDTR in Table 8. The
BSAF for DDTR accumulation into largemouth bass was estimated by the ratio
method because the regression through the plot of lipid-normalized largemouth
bass and TOC-normalized sediment produced an r2 value of 0.3. The non-
normalized data for DDTR accumulation in largemouth bass plotted with less
scatter than the normalized sediment and tissue concentrations. The
recommended BSAF of 5.0 was estimated as the average, average largemouth
bass tissue concentration divided by the average, average sediment
concentration among the sampling years and locations summarized in Table 8.
April 2014
11
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 7.
Data Pairings for Derivation of Largemouth Bass BSAF
Sediment Cone.,
Tissue Cone.,
%
Location
mg/kg dw
Sediment Sample ID
TOC, mg/kg
TOC Sample
mg/kg ww
Lipids
Tissue Sample ID
NE Basin
4.748
ODG0301-0694
16000
ODG0303-0694
8.76
1.66
OLE0108-0694
1994
5.283
ODG0302-0694
33300
SGG08-081391
11.75
5.9
OLE0105-0694
6.178
ODG0303-0694
30900
SGG09-081091
14.3
6.38
OLE0107-0694
29800
SGH08-081391
16.79
4.52
OLE0109-0694
80500
SGI10-081391
39400
SGJ06-081391
36900
SGJ07-081391
W Basin
0.494
SGJ06-081191
29800
SGH08-081391
15.47
1.33
LB-E1-02-WB-1191
1991
1.03
SGG09-080991
80500
SGI10-081391
20.66
0.67
LB-E1-03-WB-1191
1.3
SGG08-081191
39400
SGJ06-081391
1.36
SGH08-081191
36900
SGJ07-081391
1.65
SGJ07-081191
2.16
SG110-081191
W Basin
0.74
SGF07-081191
39000
SGC10-080991
76.7
7.85
OLE0103-0694
1991,
1994
1.46
SGC06-081191
28100
SGC06-081391
11.2
2.72
CIBA-LB-D1-1991
1.59
SGD10-080891
43500
SGD10-080991
21.7
11.2
CIBA-LB-D2-1991
1.64
SGC06DUP-081191
34800
SGD06-081391
30.7
5.58
CIBA-LB-D3-1991
1.73
SGC10-080891
26900
SGF07-081391
24.3
5.93
CIBA-LB-D4-1991
2.44
SGD06-081191
44.8
7.17
CIBA-LB-D5-1991
44.3
9.23
CIBA-LB-D6-1991
April 2014
12
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 7 (continued). Data Pairings for Derivation of Large Mouth Bass BSAF
Location
Sediment
Cone., mg/kg
dw
Sediment Sample ID
TOC, mg/kg
TOC Sample
Tissue Cone.,
mg/kg ww
%
Lipids
Tissue Sample ID
W Basin
1991, 1994
0.494
0.74
SGJ06-081191
SGF07-081191
39000
36500
SGC10-080991
SGC06DUP-
081391
7
9.3
4.67
2.67
LB-E3-25-WB-1191
LB-E5-32-WB-1191
(Continued)
1.03
SGG09-080991
28100
SGC06-081391
14.2
6.67
LB-E5-30-WB-1191
1.3
SGG08-081191
43500
SGD10-080991
20.4
2
LB-E6-34-WB-1191
1.36
SGH08-081191
34800
SGD06-081391
21.2
N.A.
LB-E3-23-WB-1191
1.46
SGC06-081191
26900
SGF07-081391
22.7
0.33
LB-E5-28-WB-1191
1.59
SGD10-080891
16000
ODG0303-0694
27.5
1.33
LB-E3-21-WB-1191
1.65
SGJ07-081191
33300
SGG08-081391
46.89
1.67
LB-G1-37-WB-1191
1.73
SGC10-080891
30900
SGG09-081091
2.16
SG110-081191
29800
SGH08-081391
2.44
SGD06-081191
80500
SGI10-081391
4.75
ODG0301-0694
39400
SGJ06-081391
5.28
ODG0302-0694
36900
SGJ07-081391
6.18
ODG0303-0694
SW Basin
0.272
SGC05-081391
36500
SGC06DUP-
081391
26.14
9.37
OLE0102-0694
1991, 1994
1.41
1.43
2.01
1.46
1.64
2.44
ODG0102-0694
ODG0101-0694
ODG0103-0694
SGC06-081191
SGC06DUP-081191
SGD06-081191
28100
34800
4450
16000
SGC06-081391
SGD06-081391
ODG0101-0694
ODG0202-0694
Round Pond
1994
5.86
5.99
ODG0502-0694
ODG0501-0694
16000
16000
ODG0404-0694
ODG0410-
081894
18.3
19.67
5.28
7.09
OLE0206-0694
OLE0201-0694
7.14
ODG0503-0694
16000
16000
ODG0505-0694
ODG0511-
081894
106.4
8.14
OLE0204-0694
April 2014
13
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 7
(continued). Data Pairings for Derivation of Large Mouth Bass BSAF
Sediment Cone.,
Tissue Cone.,
%
Location
mg/kg dw
Sediment Sample ID
TOC, mg/kg
TOC Sample
mg/kg ww
Lipids
Tissue Sample ID
NE Basin
3.21
SE-B1 -101101-01
84000
SE-B1-101101-01C
4.52
0.82
BF-B2-100101-01
2001
2.54
SE-B1-101101-02
140000
SE-B2-101101-01C
3.25
0.88
BF-B3-100101-01
3.15
SE-B1-101101-03
170000
SE-B3-101101-01C
13.98
1.42
BF-B4-100101-01
7.5
SE-B2-101101-01
130000
SE-B4-101101-01C
1.08
0.73
BF-B1-100101-01
6.14
SE-B2-101101-02
12000
SE-H6-0901
5.16
SE-B2-101101-03
15000
SE-H8-0901
4.04
SE-B3-101101-01
24000
SE-110-0901
5.18
SE-B3-101101-02
15000
SE-J6-0901
5.09
SE-B3-101101-03
17000
SE-B4-0901
4.55
SE-B4-101101-01
8.86
SE-B4-101101-02
5.98
SE-B4-101101-03
0.737
SE-H6-0901
0.63
SE-H8-0901
0.635
SE-110-0901
1.078
SE-J6-0901
NW
Basin
0.32
SE-B10-101101-06
9400
SE-B5-0901
7.99
0.82
BF-B10-100201-01
SE-B10-101101-
2001
0.35
SE-C6-0901
65000
01C
31.79
0.81
BF-B5-100201-01
0.63
SE-B5-101101-01
32000
SE-B10-101101-04
0.78
SE-B10-101101-01
55000
SE-B5-101101-01C
1.01
SE-F7-0901
20000
SE-C6-0901
1.15
SE-B5-101101-03
29000
SE-D10-0901
1.17
SE-B10-101101-02
23000
SE-F7-0901
1.71
SE-B5-101101-02
1.91
SE-B10-101101-03
2.49
SE-B10-101101-04
2.98
SE-B10-101101-05
April 2014
14
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
4.4 SE-D10-0901
Table 7 (continued). Data Pairings for Derivation of Large Mouth Bass BSAF
Sediment Cone.,
Sediment Sample
Tissue Cone.,
%
Location
mq/kq dw
ID
TOC, mq/kq
TOC Sample
mq/kq ww
Lipids
Tissue Sample ID
SE Basin
0.0921
SE-G3-0901
3200
SE-G3-0901
14.37
1.01
BF-B6-100201-01-F
2001
0.57
SE-B6-101101-03
7300
SE-K4-0901
0.7
SE-B6-101101-06
10000
SE-K5-0901
0.7
SE-B6-101101-04
11000
SE-J3-0901
0.76
SE-B6-101101-01
14000
SE-H4-0901
0.77
SE-H4-0901
24000
SE-B6-101101-04
0.868
SE-B6-101101-02
28000
SE-H2-0901
1.14
SE-B6-101101-05
1.24
SE-K5-0901
1.696
SE-J3-0901
1.821
SE-H2-0901
3.48
SE-K4-0901
Round Pond
10.18
SE-R1-101101-05
110000
SE-R1-101101-04
19.32
0.76
BF-R8-100201-01-F
2001
14.43
SE-R1-101101-06
120000
SE-R1-101101-01C
26.74
0.93
BF-R9-100201-01-F
25.94
SE-R1-101101-04
25000
SE-R2-101101-01C
29.01
1.01
BF-R7-100201-01-F
23000
SE-R7-101101-01C
April 2014
15
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 7 (continued). Data Pairings for Derivation of Large Mouth Bass BSAF
Location
Sediment Cone.,
mg/kg dw
Sediment Sample
ID
TOC, mg/kg
TOC Sample
Tissue Cone.,
mg/kg ww
%
Lipids
Tissue Sample ID
OU2B-SED-103C-
OU2B-SED-103C-
N Basin
0.0763
10
23400
10
2.1861
1.5
MCI 0001-10-WB-NE
OU2B-SED-402C-
OU2B-SED-402C-
2010
0.0591
10
25500
10
1.6559
0.81
MCI 0002-10-WB-NE
1.9815
0.92
MCI 0003-10-WB-NE
2.4289
2.8
MCI 0004-10-WB-NE
3.5657
2.0
MCI 0005-10-WB-NE
2.2756
2.5
MCI 0006-10-WB-NE
2.7505
3.2
MCI 0007-10-WB-NE
3.5902
2.7
MCI 0008-10-WB-NE
2.4834
2.3
MCI 0009-10-WB-NE
3.844
5.5
MCI 0015-10-WB-NE
0.6911
0.77
MCI 0022-10-WB-NW
3.73
3.5
MCI 0023-10-WB-NW
3.2596
5.3
MCI 0024-10-WB-NW
3.215
2.4
MCI 0025-10-WB-NW
4.102
4.8
MCI 0026-10-WB-NW
5.114
4.6
MCI 0027-10-WB-NW
4.883
6.3
MCI 0028-10-WB-NW
39.179
4.6
MCI 0029-10-WB-NW
9.846
3.0
MCI 0030-10-WB-NW
April 2014
16
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 7 (continued). Data Pairings for Derivation of Large Mouth Bass BSAF
Location
Sediment Cone.,
mg/kg dw
Sediment Sample ID
TOC, mg/kg
TOC Sample
Tissue Cone.,
mg/kg ww
%
Lipids
Tissue Sample ID
OU2B-SED-
OU2B-SED-203DC-
S Basin
453.5
203DC-10
10900
10
1.2515
0.81
MCI 0043-10-WB-SW
OU2B-SED-303C-
2010
1231.4
10
6980
OU2B-SED-303C-10
2.3571
1.8
MCI 0044-10-WB-SW
OU2B-SED-
OU2B-SED-DUP05C-
3.8
458.8
DUP05C-10
7590
10
2.6183
MCI 0045-10-WB-SW
2.1639
2.9
MCI 0046-10-WB-SW
4.3586
5.5
MCI 0047-10-WB-SW
3.7509
1.6
MCI 0048-10-WB-SW
9.3606
6.9
MCI 0049-10-WB-SW
4.066
4.9
MCI 0050-10-WB-SW
4.383
7.4
MCI 0051-10-WB-SW
4.4658
5.8
MCI 0052-10-WB-SW
1.4861
1.5
MCI 0064-10-WB-SE
0.7539
0.8
MCI 0065-10-WB-SE
3.597
4.5
MCI 0066-10-WB-SE
2.008
1.7
MCI 0067-10-WB-SE
3.6704
6.1
MCI 0068-10-WB-SE
1.5909
1.1
MCI 0069-10-WB-SE
0.6714
0.53
MCI 0070-10-WB-SE
3.5797
9.2
MCI 0071-10-WB-SE
3.6847
4.8
MCI 0072-10-WB-SE
2.856
2.6
MCI 0073-10-WB-SE
April 2014
17
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 8. Pairing Data for Estimating the Biota to Sediment Accumulation Factor for DDTR in Largemouth
Bass with DDTR to DDTR Conversion.
Location/-Year
Average DDTr
Sediment
Concentration
mg/kg
Average
DDTR
Sediment
Concentratio
n mg/kg1
Average DDTr
Tissue
Concentration
in Whole Body,
mg/kg wet
weight
Average DDTR
Tissue
Concentration in
Filet, mg/kg wet
weight
Average DDTR Tissue
Concentration in
Whole Body, mg/kg
wet weight2
NE Basin 1994
—
5.40
—
—
12.9
W Basin 1991
1.33
4.32
18.07
—
21.64
W Basin 1991,
1994
1.61
5.19
36.23
2.12
41.23
W Basin 1991,
1994 (Ciba Data)
SW Basin
1991, 1994
2.25
1.52
4.88
3.39
21.15
4.75
25.34
26.14
Round Pond
1994
—
6.33
—
—
48.12
NE Basin
2001
—
4.03
—
0.44
5.71
NW Basin
2001
—
3.21
—
0.72
19.89
SE Basin
2001
—
1.15
—
0.85
14.37
Round Pond
2001
—
10.1
—
2.10
25.02
N Basin
2010
—
0.0667
—
0.16
5.30
S Basin
2010
—
0.71
—
0.17
3.13
1 - Average DDTR concentration in sediment was estimated from the average DDTR concentration in sediment by multiplying by 3.24.
2 - Average DDTR concentration in whole-body largemouth bass tissue was estimated from the DDTr concentration in whole-body largemouth bass by multiplying
by 1.20.
April 2014
18
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Q
Q
Q
o
M
3000
»—
o
E
7500
E
+j
e
o
01
E
2000
¦a
a>
1500
t/5
¦n
c
c
1000
rt
F-
i
a
a
500
O
w"
Q
0
E
Q
s
t/5
Correlation of DDTr to DDTR in
Sediment
y= 3.2433x
R2 = 0.9704
100 200 300 400 500 600 700 800
Sum 4,4'-Isomers of DDD, DDE, DDT in Sediment, mg/kg
Figure 3. Correlation between DDTR and DDTr Concentrations in OU-2
sediment.
Q
Q
Q
O
V5
»—
0»
COD
E
oT
s
V5
!/)
re
CQ
S 30000
25000
20000
15000
« ^ 10000
5000
H
Q
Q
¦a
re
w"
Q
Q
y= 1.1979x
R2 = 0.9943
5000 10000 15000 20000 25000 30000 35000
Sum 4,4'-Isomers of DDD, DDE, DDT in Bass Tissue, mg/kg
Figure 5. Correlation between DDTr and DDTR Concentrations in
Largemouth Bass Tissue.
April 2014
19
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
a>
s
t/l
-------
Explanation of Remedial Goal
Derivations and Modifications
non-normalized sediment concentrations by incorporating the average lipid
content in the forage fish and the average TOC concentration in the sediment.
This conversion was done in the RGO document to simplify the back-calculation
of the DDTR concentration in sediment that is protective offish-eating wildlife.
The equation presented in the RGO document for bioaccumulation of DDTR in
forage fish was:
y = 1.3305x09395,
where y is the tissue concentration and x is the sediment concentration. This
equation assumed an average TOC in sediment of 5.5%, which is characteristic
of the northern shorelines of the Olin Basin where forage fish were collected but
was not representative of the Olin Basin and Round Pond as a whole. The
average OU-2 wide concentration of TOC in the sediment was 2.24%. If the
equation is recalculated using the OU-2 wide average TOC and lipid
concentrations, the revised equation is:
y = 2.056x07252
Thus, the sediment RG for DDTR at OU-2 is sensitive to the TOC concentration
in the sediment. If lipid content is held constant, lower sediment TOC
concentrations equate to a higher BSAF, and therefore a lower remedial goal.
Since the RGO equation assumed an average TOC concentration that was more
than twice the site-wide average, it is likely that the RG for DDTR would be lower
in areas with lower TOC concentrations. At the very least, remedial alternatives
should recognize the importance of TOC in achieving appropriate levels of risk
reduction in OU-2.
The RGO document also assumed that forage fish were the predominant
exposure pathway to aquatic-dependent wildlife at the site. EPA raised the
concern that DDTR can biomagnify in predatory fish. A RG designed to protect
forage fish and wildlife that feed on smaller fish may not be sufficiently protective
April 2014
21
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
of predatory fish and the wildlife that feed on larger fish, such as the great blue
heron, osprey, and bald eagle. DDTR is known to biomagnify in predatory fish at
the top of the food chain. For greater mathematical precision, and to incorporate
the diet of the receptors as they appeared in the BERA (MACTEC 2010a) instead
of using a short cut that focused on the forage fish portion of the diet as was
done in the RGO document, EPA calculated RGs using the dietary compositions
as reported in the BERA repeated here as (Table 9). To incorporate all dietary
items, BSAFs were developed by EPA for DDTR accumulation in predatory fish,
aquatic insects, crayfish, and frogs. Crayfish and frogs were lesser components
of the diets and made generally made less difference to the calculations, which is
why the RGO document did not include these. However, bioaccumulation
estimates based on historical aquatic insect data showed relatively high
bioaccumulation of DDTR into these organisms, which is potentially important to
organisms such as little blue heron and pied-billed grebe, whose diets were
assumed to be comprised of 25% or more aquatic insects.
Table 9. Dietary Fractions of Receptors used in Food-chain Model Calculations to
Estimate RGOs.
Fraction
Fraction
Fraction
Terr.
Aquatic
Forage
Predatory
Fraction
Fraction
Insect
Insects
Fish
Fish
Crayfish
Frogs
fraction
Receptor
Pied-billed grebe
0.6
0.2
0
0.2
0
0
Belted kingfisher
0
1
0
0
0
0
Belted kingfisher
0.19
0.51
0
0.05
0.25
0
Omnivore
Little blue heron
0.25
0.75
0
0
0
0
Great blue heron
0.05
0.5
0.35
0
0.1
0
Carolina wren
0
0
0
0
0
1
The BSAFs for DDTR accumulation in forage fish and terrestrial insects are the
same as developed in the RGO document. Table 10 summarizes the BSAFs that
were used in the food-chain models to develop the RGOs presented in this
technical memorandum.
April 2014
22
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 10. Biota-to-Sediment Accumulation Factors Used in Remedial Goal Option
Calculations.
Prey Item Average Normalized Non-normalized Source
Lipid Regression Regression
Content, Eqn. Equation*
%
Forage Fish
3.78
y = 3.4605x° 7252
y = 2.056x07252
RGO
Document
Predatory Fish
(bass)
N.A.
N.A.
y = 5x
This
document
Aquatic Insects
3.94
y = 4.76x0981
y = 7.79x0981
This
document
Crayfish
N.A.
N.A.
y = 0.88x
This
document
Frogs
1.60
y = 0.50x
y = 0.36x
This
document
Terrestrial
3.64
y = 1.46x to
y = 2.35x to
RGO
Insects
y=5.03x
y=8.08x
Document
*lf a normalized regression equation appears in the table, the non-normalized
regression equation was computed assuming an average total organic carbon
content for OU-2 of 2.24%.
The BSAF for DDTR accumulation in predatory fish was discussed in the
previous section, using the data presented in Tables 7 and 8, and Figures 3, 4,
and 5.
The bioaccumulation of DDTR in aquatic insects was developed by EPA because
it was not included in the RGO Development Report (MACTEC 2010b). Aquatic
insects were collected and analyzed for DDTR in 1994 and 2001 (Table 11). The
average concentrations in aquatic insects normalized by lipids and TOC were
plotted in Figure 6.
Frogs were analyzed for DDTR in 1994 (Table 12). Figure 7 shows the frog
BSAF curve fit to normalized frog data. Because the plot of normalized frog data
had an r2 of 0.6 the BSAF for frogs was estimated by the ratio approach, which
resulted in a normalized BSAF of 0.5 for DDTR accumulation in frogs. If the
normalized BSAF for DDTR in frogs was adjusted by the average lipid content in
frogs and the average TOC in sediments the non-normalized BSAF was
approximated as 0.36.
April 2014
23
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Crayfish were collected in 1994 and analyzed for DDTr. Sediment data collected
in 1994 for DDTr and 1991 sediment data, which was only analyzed for DDTr,
was paired. Crayfish were collected from the west basin and from the Olin Ditch.
The data for crayfish used the ratio method to estimate a BSAF for crayfish
(Table 14). The BSAF for crayfish was calculated by the ratio method as the
average of the average tissue concentrations of DDTr divided by the average of
the average DDTr sediment concentrations. The estimated BSAF for DDTR in
crayfish was estimated as 0.88 for DDTr by this approach.
Use of the expanded dietary compositions for each receptor together with the
lower TOC concentration represented by the OU-2 wide average results in lower
RGs compared to those derived in the RGO document (Table 15). However, EPA
recognizes that there is uncertainty with the aquatic insect and crayfish BSAFs
due to their small sample sizes. It is expected that remediation of sediments to
the clean-up levels presented in Table 30 of the ROD will reduce average
concentrations across OU-2 to a level where average exposures are less than
even the conservative levels represented by the adjusted RGs presented in
Table 15. Therefore, EPA is not specifying the adjusted RGs as clean-up levels
for OU-2.
April 2014
24
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 11. Data Pairing for Evaluation of Bioaccumulation of DDTR in Aquatic Insects.
Location
Sediment
Cone.,
mg/kg dw
Sediment Sample ID
Total
Organic
Carbon
(TOC)
Fraction
Organic
Carbon
TOC Norm.
Sediment
Concentration
(mg/kg TOC)
Tissue
Cone.,
mg/kg
WW
Tissue Sample ID
Fraction
Lipids
Lipid Norm. Aquatic Insect
Tissue Concentration
(mg/kg lipid)
SE
Basin
AI-1
0.77
SE-B6-101101-01
25000
0.025
31.4
11.06
AI-1 -060101
0.0466
237
0.76
SE-B6-101101-02
24000
0.024
31.0
11.026
AI-1 (0700)-070201
0.051
216
0.57
SE-B6-101101-03
23.3
10.71
AI-1 (0715)-070201
0.0528
203
0.7
SE-B6-101101-04
28.6
1.14
SE-B6-101101-05
46.5
0.7
SE-B6-101101-06
28.6
Averages
0.77
31.6
10.9
219
NE
Basin
0.635
SE-110-0901
24000
0.024
26.5
5.1
AI-2-060101
0.0417
122
AI-2
7.5
SE-B2-101101-01
140000
0.14
53.6
4.43
AI-2 (0800)-070201
0.0499
89
6.14
SE-B2-101101-02
43.9
4.186
AI-2 (0815)-070201
0.038
110
5.16
SE-B2-101101-03
36.9
April 2014
25
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Averages
4.86
40.2
4.57
107
Table 11. Data Pairing for Evaluation of Bioaccumulation of DDTR in Aquatic Insects (Continued).
Location
Sediment
Cone.,
mg/kg
dw
Sediment Sample ID
Total
Organic
Carbon
(TOC)
Fraction
Organic
Carbon
TOC Norm.
Sediment
Concentration
(mg/kg TOC)
Tissue
Cone.,
mg/kg
WW
Tissue Sample ID
Fraction
Lipids
Lipid Norm. Aquatic
Insect Tissue
Concentration (mg/kg
lipid)
SW
Basin
0.411
SE-B4-0901
17000
0.017
24.2
12.74
AI-6-060101
0.0369
345
AI-6
8.74
AI-6 (0915)-070201
0.0444
197
Averages
0.41
24.2
10.7
271
Round
Pond
10.18
SE-R1-101101-01
120000
0.12
88.5
13.092
AI-4 (0900)-070201
0.0527
248
AI-4
20.55
13.79
26.03
10.28
14.66
SE-R1-101101-02
SE-R1-101101-03
SE-R1-101101-04
SE-R1-101101-05
SE-R1-101101-06
110000
0.11
119.9
226.3
89.4
127.5
178.7
17.69
AI-4-060101
0.0519
341
Averages
15.9
138.4
15.4
295
April 2014
26
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 11. Data Pairing for Evaluation of Bioaccumulation of DDTR in Aquatic Insects (Continued).
Location
Sediment
Cone.,
mg/kg dw
Sediment Sample ID
Total
Organic
Carbon
(TOC)
Fraction Organic
Carbon
TOC Norm.
Sediment
Concentration
(mg/kg TOC)
Tissue
Cone.,
WW
mg/kg
Tissue Fraction
Sample ID Lipids
Lipid Norm.
Aquatic Insect
Tissue
Concentration
(mg/kg lipid)
Round
Pond
2.8
SE-R7-101101-01
23000
0.023
122
27.3
AI-3-060101 0.0436
626
AI-3
2.7
SE-R7-101101-02
117
2.2
SE-R7-101101-03
96
2.4
SE-R2-101101-01
25000
0.025
96
2.2
SE-R2-101101-02
88
3
SE-R2-101101-03
120
10.18
SE-R1-101101-01
120000
0.12
88.5
20.55
SE-R1-101101-02
110000
0.11
178.7
13.79
SE-R1-101101-03
119.9
26.03
SE-R1-101101-04
226.3
10.28
SE-R1-101101-05
89.4
14.66
SE-R1-101101-06
127.5
Averages
9.75
122
27.3
626
April 2014
27
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 11
Data Pairing for Evaluation of Bioaccumulation of DDTR in Aquatic Insects (Continued).
Location
Sediment
Cone.,
mg/kg dw
Sediment
Sample ID
Total
Organic
Carbon
(TOC)
Fraction
Organic
Carbon
TOC Norm.
Sediment
Concentration
(mg/kg TOC)
Tissue
Cone., Tissue Fraction
mg/kg ww Sample ID Lipids
Lipid Norm. Aquatic
Insect Tissue
Concentration (mg/kg
lipid)
0.00101
RDG0201-0694
16000
0.16
0.0631
RIN0613-
0.048 0794 0.0228
2.11
Reference
0.00501
RDG0202-0694
16000
0.16
0.3131
1994
0.003465
RDG0203-0694
16000
0.16
0.2166
0.003165
RDG0301-0694
16000
0.16
0.1978
0.003035
RDG0302-0694
985
0.0099
3.0812
0.001775
RDG0303-0694
9470
0.095
0.1874
0.00319
RDG0401-0694
5880
0.059
0.5425
0.00417
RDG0402-0694
3510
0.035
1.1880
0.00283
RDG0403-0694
13300
0.13
0.2128
0.00189
RDG0601-0694
16000
0.16
0.1181
0.00473
RDG0602-0694
8540
0.085
0.5539
0.00473
RDG0603-0694
11100
0.11
0.4261
Averages
0.00325
0.592
0.048
2.11
April 2014
28
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
BSAF Plot for DDTR Accumulation in Aquatic Insects Normalized
by TOC in Sediment & Lipid in Tissues
>
n
¦a
c
c
o
o
'•M
'•M
5
+-»
3
c
O"
5
'5.
+-»
c
~
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 12. Data Pairing for Frog Samples.
Location
DDTR
Sediment
Cone.,
mg/kg dw
Sediment Sample
ID
Total
Organic
Carbon
(TOC),
mg/kg
TOC Norm.
Sediment
Concentration
(mg/kg TOC)
DDTR
Tissue
Cone.,
mg/kg ww
Tissue Sample ID
Percent
Lipids
Norm. Aquatic Insect
Tissue Concentration
(mg/kg lipid)
NE Basin
0.635
SE-110-0901
24000
0.54
OBFXX09-0894
2.95
18.31
1994
7.5
6.14
5.16
SE-B2-101101-01
SE-B2-101101-02
SE-B2-101101-03
140000
0.188
OBFXX08-0894
1.43
13.15
Averages
4.86
82000
59.25
0.364
15.73
NW Basin
1.59
SGD10-080891
43500
0.12
OBFXX12-0894
0.71
16.90
1994
1.73
SGC10-080891
39000
0.982
1.166
1.019
OBFXX11-0894
OBFXX02-0794
OBFXX10-0894
1.75
1.74
3.26
56.11
67.01
31.26
Averages
1.66
41250
40.24
0.82
42.82
SE Basin
1994
0.77
SE-B6-101101-01
25000
0.023
OBFXX07-0894
0.51
4.51
0.76
SE-B6-101101-02
24000
0.402
OBFXX06-0894
2.27
17.71
0.57
SE-B6-101101-03
0.7
SE-B6-101101-04
1.14
SE-B6-101101-05
0.7
SE-B6-101101-06
Averages
0.77
24500
31.56
0.2125
11.11
Round
Pond
10.18
SE-R1-101101-01
120000
0.315
OBNXX01-0794
1.45
21.72
1994
20.55
SE-R1-101101-02
110000
0.4
OBFXX05-0794
1.44
27.78
13.79
SE-R1-101101-03
2.785
OBFXX04-0794
1.55
179.68
26.03
SE-R1-101101-04
0.307
OBFXX03-0794
0.99
31.01
10.28
SE-R1-101101-05
14.66
SE-R1-101101-06
Averages
15.91
115000
138.39
0.952
65.05
April 2014
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ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 13. Data Pairing and Normalization for Frog Tissue.
Location
Average DDTR
Concentration
in Sediment,
mg/kg
Average DDTR
Concentration
in Frogs, mg/kg
Average TOC-
Normalized
Sediment Cone.,
mg/kg TOC
Average Lipid-
Normalized Frog
Tissue Cone.,
mg/kg-lipid
NE Basin
4.86
0.364
59.25
15.73
NW Basin
1.66
0.82
40.24
42.82
SE Basin
0.77
0.2125
31.56
11.11
Round Pond
15.91
0.95175
138.39
65.05
Lipid-Normalized Frog Tissue
exi
a
70
a£
H
Q
exi
S
60
Q
t/T
50
¦a
O)
exi
o
40
N
u.
¦a
"re
c
a
30
S
!-
o
a
o
20
2
'¦M
re
10
¦a
La
J-J
a
a
a>
0
~
u
s
o
u
y = 0.475x
R2 = 0.61
~ Normalized
0 50 100 150
TOC-Normalized DDTR Concentration in Sediment,
mg/kg-TOC
Figure 7. Lipid-normalized DDTr concentration in bullfrogs plotted against TOC-normalized DDTR concentration in
sediment showing correlation coefficient.
April 2014
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ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 14 Data Pairing for Crayfish Tissues.
DDTr
Total
DDTr
Sediment
Organic
TOC Norm.
Tissue
Norm. Aquatic Insect
Cone.,
Carbon
Sediment
Cone.,
Tissue
mg/kg
(TOC),
Concentration
mg/kg
Percent
Concentration
Location
dw
Sediment Sample ID
mg/kg
(mg/kg TOC)
WW
Tissue Sample ID
Lipids
(mg/kg lipid)
Wastewater
Ditch
1994
0.73
SGBD05-082091
29400
24.83
0.969
OCS0102-0694
1.34
72.31
0.304
SGBD06-082091
32700
9.30
0.425
OCS0103-0694
1.04
40.87
0.437
OCS0103-0694 dup
0.494
OCS0104-0694
1.26
39.21
0.688
OCS0105-0694
1.56
44.10
1.637
OCS0106-0694
3.03
54.03
0.522
OCS0107-0694
1.4
37.29
1.161
OCS0108-0694
2.75
42.22
1.448
OCS0109-0694
3.15
45.97
0.548
OCS0110-0694
1.58
34.68
Averages
0.517
17.06
0.833
45.63
W Basin
1.73
SGC10-080891
39000
44.36
0.677
OCTXX01-0694
2.6
26.04
1994
1.46
SGC06-081191
28100
51.96
1.64
SGC06DUP-081191
36500
44.93
0.705
ODG0101-0694
4450
158.43
0.67
ODG0102-0694
0.986
ODG0103-0694
Averages
1.20
47.08
0.677
26.04
April 2014
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ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
Table 15. Summary of Sediment Remedial Goals for DDTR Assuming 2.24% Total Organic Carbon
in Sediments and Comparing with RGO Document.
RGO Document This Document
Receptor
NOAEL
LOAEL
Geometric
Mean
NOAEL
LOAEL
Geometric
Mean
Pied-billed grebe
0.37
1.2
0.66
0.096
0.12
0.11
Belted Kingfisher
0.69
1.2
0.91
0.105
0.14
0.12
Belted Kingfisher Omnivore Diet
0.28
0.38
0.33
0.111
0.144
0.13
Little Blue Heron
0.48
0.71
0.58
0.107
0.138
0.12
Great Blue Heron
1.3
2.1
1.7
0.265
0.337
0.30
April 2014
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ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
REFERENCES
Beckvar, N., Dillon, T., and L.B. Read. 2005. Approaches for linking whole-body
fish tissue residues of mercury or DDT to biological effects thresholds. Environ.
Tox. Chem. 24(8): 2094-2105.
Carlisle, J. C., Lamb, D. W., and Toll, P. A. 1986. Breaking Strength an
Alternative Indicator of Toxic Effects on Avian Eggshell Quality. Environ. Toxicol.
Chem. 5(10): 887-890.
Cecil, H. C., Harris, S. J., and Bitman, J. 1978. Liver mixed function oxidases in
chickens: Induction by polychlorinated biphenyls and lack of induction by DDT.
Arch. Environ. Contam. Toxicol. 7(3): 283-90.
Crawford, R.B. and Guarino, A.M. 1976. Effects of DDT in Fundulus: studies on
toxicity, fate, and reproduction. Arch. Environ. Contam. Toxicol. 4(3): 334-338.
Davison, K. L., Engebretson, K. A., and Cox, J. H. 1976. P,p-DDT and p,p'-DDE
Effects on Egg Production, Eggshell Thickness, and Reproduction of Japanese
Quail. Bull. Environ. Contam. Toxicol. 15(3): 265-70.
Gakstatter JH, Weiss CM. 1967. The elimination of DDT-C14, dieldrin-C14, and
lindane-C14 from fish following a single sublethal exposure in aquaria. Trans Am
Fish Soc 96:301-307.
MACTEC 2010a. Part 2. Updated Ecological Risk Assessment. Operable Unit 2,
Olin Corporation, Mcintosh, Alabama. Prepared by MACTEC, Kennesaw, GA.
May 2010.
MACTEC 2010b. Remedial Goal Option Report for the Development of
Preliminary Remedial Goals in Sediment. Operable Unit 2, Mcintosh, Alabama.
(Revision 3) Prepared by MACTEC, Kennesaw, GA. April 2012.
Mahoney, J.J. Jr. 1975. DDT and DDE Effects on Migratory Condition in White-
throated Sparrows. J. Wildl. Mgmt. 39: 520-7.
Raimondo, S., B.J. Montague and M.G. Barron. 2007. Determinants of variability
in acute to chronic toxicity ratios for aquatic invertebrates and fish. Environ.
Toxicol. Chem. 26:2019-2023.
URS 2002. OU-2 RGO Support Sampling Report, Mcintosh Plant Site, Olin
Corporation, Mcintosh, Alabama. Prepared for Olin Corporation, Mcintosh,
Alabama by URS Corporation, Baton Rouge, Louisiana. April 2002.
April 2014
34
ROD Olin Mcintosh OU-2
Appendix 1
-------
Explanation of Remedial Goal
Derivations and Modifications
USEPA. 2007. Ecological Soil Screening Levels for DDT and Metabolites.
OSWER Directive 9285.7-57. http://www.epa.gov/ecotox/ecossl/pdf/eco-
ssl ddt.pdf
April 2014
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ROD Olin Mcintosh OU-2
Appendix 1
-------
APPENDIX 2: STATE CONCURRENCE LETTER
-------
Robert J. Bentley
Governor
Alabama Department of Environmental Management
adem.alabama.gov
1400 Coliseum Blvd. 36110-2400 • Post Office Box 301463
Montgomery, Alabama 36130-1463
{334)2717700 « FAX (334) 271-7950
September 18, 2013
CERTIFIED MAIL # 91 7199 9991 7030 3429 6219
Lance R. LeFleur
Director
ADEM
Ms. Beth Walden
Remedial Project Manager
U.S. Environmental Protection Agency
Atlanta Federal Center
61 Forsyth Street
Atlanta, GA 30303-8960
RE: ADEM Review and Concurrence:
Draft Record of Decision for OU2 dated September 2013
Dear Ms. Walden:
The Department has reviewed the draft submittal of the ROD for Olin Corporation's Mcintosh
facility. Based on our review, the Department concurs with the selected remedy, in-situ capping,
with the following notifications:
1. The Department has concerns with the preliminary remedial goal (PRG) for the
contaminant of concern (COC) DDTr. The value, outlined in the ROD, differs from the
PRG currently established for portions of the floodplain previously designated as
protective in OU-2. ADEM recommends establishing a consistent cleanup standard for
the entire floodplain.
2. The proposed PRG for DDTr in the draft ROD for the Olin facility may not be
appropriately calculated due to the use of the historical data applied to generate the
remediation values. The use of historical data that does not account for remedial actions
completed that improve the bioavailable concentration of DDTr may yield a remediation
value that is not accurately calculated.
Please note that on September 16, 2013, the Department provided additional comments on the
ROD electronically to address general grammatical concerns. If you have any questions
concerning this matter, please contact Mrs. Sonja B Favors at 334-279-3067.
Sincerely,
Land Division
PDD/SBF/nbf
Birmingham Bnmch
110 Vulcan Road
Birmingham, AL 35209-4702
(205) 942-6168
(205) 9411603 (FAX)
Decatur Branch
2715 Sandlfn Road, S.W.
Decatur, Al 35603-1333
(256)353-1713
(256) 340-9359 (FAX)
^'Yr &
-7
Mobile Branch
Moblte-Coastal
*
*
2204 Perimeter Road
4171 Commanders Drive
•
Mobile, AL 36615-1131
Mobile, AL 36615-1421
,v
(251) 450-3400
(251) 432-6533
(251) 479-2593 (FAX)
(251) 432 6598 (FAX)
-------
APPENDIX 3: RESPONSIVENESS SUMMARY
Table of Contents
APPENDIX 3: RESPONSIVENESS SUMMARY
INTRODUCTION
SUMMARY OF COMMUNITY RELATIONS ACTIVITIES
OVERVIEW
SUMMARY OF COMMENTS AND RESPONSES
APPENDIX 3.1 - COPIES OF COMMENT LETTERS SUBMITTED DURING THE
COMMENT PERIOD
APPENDIX 3.2 - COPIES OF COMMENT LETTERS SUBMITTED AFTER THE
COMMENT PERIOD
APPENDIX 3.3-MAY 22, 2013 PUBLIC MEETING TRANSCRIPT
-------
Responsiveness Summary
SNTRODUCTSON
This responsiveness summary provides a summary of the significant comments and
criticisms submitted by the public on the U.S. Environmental Protection Agency's
(EPA's) May 2013 Proposed Plan for the Olin Mcintosh Operable Unit 2 Superfund Site,
and the EPA's responses to those comments and concerns. A responsiveness
summary is required by the National Oil and Hazardous Substances Pollution
Contingency Plan at 40 C.F.R. § 300.430(f)(3)(F). All comments summarized in this
document have been considered in the EPA's final decision in the selection of a remedy
to address the contamination at the Site.
SUMMARY OF COMMUNITY RELATIONS ACT1VITES
The May 2013 Proposed Plan, which identified the EPA's preferred remedy and the
basis for that preference, including supporting analyses and information, was made
available to the public in the administrative record file at the EPA Region 4 Records
Center in its' Atlanta office, the Mcintosh Town Hall, and an EPA Region 4 webpage.
The notice of availability of the above-referenced documents and the announcements of
a public meeting date were published in the Washington County News and the Call
News Newspapers on May 15 and 17, 2013, respectively. A news release announcing
the Proposed Plan, which included the public meeting date and location was issued to
various media outlets on the same dates. In addition, the EPA presented the schedule
for the upcoming Proposed Plan and a brief description of the proposed remedy in a
February 12, 2013 town hall meeting.
A public comment period was open from May 22, 2013 to June 21, 2013. The EPA's
response to the comments received during this period is included in the
April 2014
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ROD Olin Mcintosh OU-2
Appendix 3
-------
Responsiveness Summary
Responsiveness Summary, which is part of this Record of Decision.
On May 22, 2013, the EPA conducted a public meeting in the evening at the Mcintosh
Town Hall to inform local officials and interested citizens about the Superfund process,
to review current and planned remedial activities at the Site, to discuss the Proposed
Plan, and to listen to and respond to questions and comments from the area residents
and interested parties. A total of less than 15 people attended the public meeting,
including one resident, one media representative, representatives of Olin Corp. and
BASF, and state officials.
OVERVIEW
The EPA's selected remedy includes, in-situ capping consisting of a multi-layered
engineered cap. In habitat areas, the uppermost layers of the cap will be designed using
suitable habitat materials. Reactive materials, containing sequestering materials, may
be used to reduce the potential for contaminants to migrate through the cap. The
institutional controls, including deed and use restrictions currently in place as a result of
OU-1 will be amended to include the OU-2 remedial footprint; the engineering controls,
including the berm and gate system, signs, fencing, and security monitoring, will be
employed long enough to limit risks to human receptors. Long-term monitoring will
include cap maintenance; topographic surveys; sediments samples, surface water and
porewater monitoring; fish tissue and other biota monitoring. Because this alternative
will result in hazardous substances, pollutants, or contaminants remaining onsite above
levels that allow for unlimited use and unrestricted exposure, a CERCLA statutory
review will be conducted every five years after the completion of the remediation to
ensure that the remedy is, or will be, protective of human health and the environment.
Additional sampling will be performed in the channel connecting Round Pond to the
Basin and the perimeter floodplain soils that are often inundated; and the former
wastewater and discharge ditch to further refine the remedial footprint.
April 2014
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ROD Olin Mcintosh OU-2
Appendix 3
-------
Responsiveness Summary
While the public who commented, supported the preferred remedy, all of the public who
commented, either disagreed or had concerns with the DDTR remedial goals for
sediment, soil, and fish tissue.
SUMMARY OF COMMENTS AND RESPONSES
Three letters were received via U.S. mail during the comment period from May 22, 2013
to June 21, 2013. Copies of the comments letters are provided in Appendix 3. A copy of
the comment letters received after the comment period ended is also provided as a
separate attachment to this Record of Decision, see Appendix 3.2. The EPA in its
discretion has decided to respond to them (to the extent that they comments are not
already addressed in other comment response and where practicable) despite the fact
that they were submitted after the comment period closed. A summary of the comments
contained in the letters and the response to those comments are below.
A copy of the transcript from the public meeting is provided as an attachment to this
Record of Decision and is available in the Administrative Record, which is available at
the following information repositories:
Mcintosh Town Hall
206 Commerce Street
Mcintosh, AL 36553
(251) 944-2428
USEPA Region 4 Records Center
61 Forsyth Street
Atlanta, GA 30303
(404) 562-8946
April 2014
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ROD Olin Mcintosh OU-2
Appendix 3
-------
Responsiveness Summary
Electronic documents are posted at the EPA Region 4 webpage:
http://www.epa.gov/region4/foiapgs/readingroom/index.htm
Commenters on the Proposed Plan included Olin Corporation, BASF Corporation, and
Alabama Department of Environmental Management. Numerous comments were
similar, and the comments were focused on a limited number of topics. In addition, it
was recognized that the comments required comprehensive responses.
Rather than respond to each comment individually (which would have resulted in
repetitive responses), or respond by referring back to the first comment /response on a
particular topic (which would have resulted in undue emphasis on that first comment or
response), comments were grouped into three subjects - 1) consistency with the Ciba
Geigy OU-3 Superfund Site remedy which shares the same floodplain as the Olin OU-2
Superfund Site; 2) technical and scientific basis in developing the DDTR clean up levels
and whether they can be achieved; 3) potential for recontamination of the in-situ cap.
Many of these subjects are interrelated and readers are urged to review the
Responsiveness Summary in its entirety. In addition, in a very limited number of cases a
comment which seemed best suited to more than one category was included in other
appropriate categories.
For ease of reading, the comments received are presented in normal text and the EPA's
responses are in italics.
Consistency with Ciba-Gieqy OU-3 Remedy:
Comments:
• EPA management has consistently upheld the remedy chosen for the
floodplain remediation and performance goal set for DDTr. (BASF)
• In the proposed plan for the Olin site, EPA has recommended a set of
DDTR remedial goals for OU-2 that differ from BASF's OU-3 even within
this overlapping area. This inconsistency is troubling given that the
existing remedy not only was developed with input and approval from EPA,
April 2014
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ROD Olin Mcintosh OU-2
Appendix 3
-------
Responsiveness Summary
ADEM and the NRD trustees, but has proven to be successful and
protective. (BASF)
• The Department has concerns with the DDTR remedial goal because it
differs from the remedial goal previously designated for portions of the
floodplain. ADEM recommends a consistent cleanup standard. (ADEM)
EPA Response:
The evaluation and analysis in both the Ciba and Olin ecological risk assessments
concluded that the DDTR remedial goals for soils and sediments should be <1 mg/kg
(ppm) in order to be protective of the environment and certain species effected by
DDTR contamination. The 15 ppm cleanup level for DDTR in soils/sediments selected
in the Ciba 0U- 3 July 1995 ROD was a risk-management decision based not on the
level determined to be protective (<1 mg/kg), but upon a concern that".. .remediating to
1 ppm is not practical because this would require extensive excavation and destruction
of the bottom land hardwood forrest and the cypress tuepelo swamp". The EPA also
issued an ESD for the Ciba OU-3 in October of 2008. Though the cleanup level for
DDTR was not changed, this ESD did require additional actions (placement of a sand
cover in ecologically sensitive areas and monitoring with natural recovery). It was
determined that an application of a sand cover could be performed in ecologically
sensitive areas without destroying the habitat. The monitoring requires that, in addition
to the 15 ppm DDTR sediment cleanup level, tissue concentrations in the mosquitofish
(gambusia affinis) be used as a measure of protectiveness of piscivorous birds that feed
on mosquitofish. A performance standard of 0.3-1.5 ppm DDTR in tissue is being used,
but has not been achieved. It is still possible that additional remedial action, beyond
natural recovery, will be necessary at Ciba OU-3.
One of the significant differences between the habitats at Olin OU-2 and Ciba OU-3 is
that at Olin the habitat includes larger basins of open water which supports a more
extensive fishery than at the Ciba Site. It is noteworthy that in 2010, fish samples were
collected from the Olin Basin . The forage fish samples ranged from 0.878 to 1.82
April 2014
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ROD Olin Mcintosh OU-2
Appendix 3
-------
Responsiveness Summary
mg/kg in brook silversides and 0.557 to 5.46 mg/kg in bluegill; the predatory
(largemouth bass) fish samples ranged from 0.674 to 39.2 mg/kg.
Scientific and Technical Issues
Comment:
• EPA has chosen to propose DDTR remedial goals for Olio's OU-2 that
are so low they may be technically impracticable to achieve. (BASF)
EPA Response:
Success indicated by the 2013 monitoring data at BASF has proven that caps
containing organic carbon are capable of reducing surface sediment concentrations,
sequestering contamination, and decreasing exposure to fish. The EPA has selected
cleanup levels at other Sites for DDTR at or below the levels in the OU-2 ROD. Based
upon experience in implementing those other remedial actions and anticipated
successfulness of capping at the Olin, the EPA is confident that the DDTR cleanup level
can be attained and over time the environment can be restored to a state protective of
human health and the environment.
Comment:
• BASF strongly believes that the Proposed Plan for the Olin OU-2, and
specifically the proposed DDTr remedial goals, must be based on sound
scientific and technical principles, and consistent with prior agency
management decisions. The proposed DDTR remedial goals for Olin fall
short of this mark. (BASF)
EPA Response:
The preliminary remedial goals (PRGs) described in the FS and PP documents are
based upon current technical and scientific literature and have a strong scientific
backing as explained in both the Olin and Ciba ecological risk assessments. An
explanation of the calculation of the remedial goals is presented in the Remedial Goal
Option Report and in Appendix 1 to this ROD.
April 2014
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ROD Olin Mcintosh OU-2
Appendix 3
-------
Responsiveness Summary
Comment:
• The proposed PRG for DDTR may not be appropriately calculated due to
the use of historical data applied to generate remediation values. (ADEM)
EPA Response:
Remedial goals for DDTR for piscivorous birds were derived by Olin in the RGO report
using forage fish tissue data and sediment data from 1994 and 2001. Sediment and fish
tissue data from each of those years were paired to derive Biota-Sediment
Accumulation Factors (BSAF) for DDTR. The RGO report utilized food chain dose
equations from the ecological risk assessment to identify fish tissue concentrations that
trigger risk to piscivorous birds and mammals. The BSAFs were then used to back-
calculate sediment concentrations that through bioaccumulation result in fish tissue
concentrations triggering risk. BSAFs are derived from regression equations of paired
sediment and fish tissue data, in which sediment DDTR concentrations are normalized
to organic carbon content, and fish tissue concentrations are normalized to lipid content.
While DDTR concentrations in site sediment and fish tissue in OU-2 may have
decreased since the data were originally collected, the BSAF, which defines the
relationship between sediment and tissue concentrations, is not expected to vary
significantly over time. Therefore, the remedial goal does not change over time. As
sediment concentrations decrease, fish tissue concentrations decrease, but the
relationship between sediment and fish tissue remains relatively constant, provided that
there is reasonable certainty in the data pairings used to derive the BSAF. In addition,
fish tissue data collected in 2010 and analyzed for DDTR subsequent to the RGO report
confirm the BSAF relationship observed in the historical data. Refer to Appendix 1 in the
ROD for details of how the preliminary remedial goals were calculated.
In summary, the BSAF represents the relationship between sediment and fish tissue
concentrations. The BSAF is not expected to vary greatly over time. As sediment
concentrations decrease, fish tissue concentrations decrease, but the relationship
April 2014
7
ROD Olin Mcintosh OU-2
Appendix 3
-------
Responsiveness Summary
between sediment and fish tissue remains relatively constant, provided that there is
reasonable certainty in the data pairings used to derive the BSAF. Historical data from
the Ciba BERA was added. The measurement of DDTr instead of DDTR in historical
data was accounted for by the ratio observed in the data. Refer to Appendix 1 in the
ROD for details of how the preliminary remedial goals were calculated.
Ciba-Geiqy as art Upqradient Source
Comments:
• The DDTR PRG may not be achievable as a result of upgradient,
background sources of DDTR at the Ciba-Geigy Superfund Site. (Olio)
• The DDTR PRG for forage fish may not be achievable because of potential
migration of DDTR from the BASF facility. (Olin)
EPA Response:
Based upon an evaluation consistent with Agency policy and guidance on determining
background levels of contamination, the DDTR remedial goals are above background in
the Mobile/Tsnsas River basin - by an order of magnitude. Data collected by BASF as
part of the 2008 Ciba-OU-3 ESD indicated that the DDTr footprint in the sediments is
stable and consistent with past investigations; natural recovery is occurring; sediment
transport to the Tombigbee River is likely not occurring, and transport is minimal and
localized within the ecologically sensitive areas that were not remediated in the initial
cleanup phase conducted in 1998.
Figure 1 in Appendix 1 shows that DDTR concentrations in Round Pond were 0.102
mg/kg in 2009. If contaminant migration were occurring from the property to the north,
the DDTR concentrations in the northern portion of OU-2 would be in the parts per
million range. Moreover, the DDTR concentrations in sediments in the northern portion
of the Olin Basin have declined overtime. The DDTR concentrations in sediments of the
southern portion of the Olin Basin have shown a slower rate of decline. Any past or
ongoing source of DDTR to the Olin Basin are diffuse in nature and are occurring at a
lower concentration than the concentrations in the sediments on the Ciba-Geigy
April 2014
8
ROD Olin Mcintosh OU-2
Appendix 3
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Responsiveness Summary
Superfund Site. Hydrodynamic modeling indicated that the current velocities through the
floodplain are insufficient to erode floodplain soils. The most recent sampling events in
the Olin floodplain and Basin have shown that DDTR concentrations are in the ppb -
well below the cleanup goal. There is no evidence of Ciba-contaminated sediments
appreciably accumulating in the Basin under current conditions.
April 2014
9
ROD Olin Mcintosh OU-2
Appendix 3
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APPENDIX 3.1 - COMMENT LETTERS DURING PUBLIC COMMENT PERIOD
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Olin
3855 North Ocoee Street, Suite 200, Cleveland, TN 37312
(423) 336-4600 FAX: (423) 336-4166
June 19, 2013
Ms. Beth Walden
Remedial Project Manager
U.S. Environmental Protection Agency
Atlanta Federal Center
61 Forsyth Avenue
Atlanta, Georgia 30303-8960
Re: Submittal of Comments on the May 2013 USEPA Proposed Plan for Olin Mcintosh
Operable Unit 2
Mcintosh, Alabama
Dear Ms. Walden:
Olin Corporation (Olin) submits the attached comments on the May 2013 Proposed Remedial
Action Plan for the Olin Mcintosh Operable Unit 2, located in Mcintosh, Alabama. Please let me
know if you have any questions. I can be reached at (423) 336-4388 or via e-mail
(kdroberts@olin.com).
Sincerely,
OLIN CORPORATION
Keith D. Roberts
Director, Environmental Remediation
cc: C. A. Hunt - Olin
T. E. Stroth - Olin
L. D. O'Brien - Olin
C . E. Draper - AMEC
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June 19, 2013
COMMENTS ON THE USEPA PROPOSED PLAN FOR
olin Mcintosh operable unit 2
Washington County, Alabama
1. USEPA's Proposed Plan for Olin Mcintosh Operable Unit 2 (OU-2) recommends in-situ
capping as the preferred alternative for remediation of sediments. Olin Corporation
supports the selection of USEPA's preferred alternative as a cost effective remedy that
will provide short and long term protectiveness of human health and the environment.
2. Page 6 - The DDTR preliminary remediation goal (PRG) for OU-2 sediments is stated
as 0.33 to 1.7 mg/kg. The DDTR PRG for OU-2 floodplain soils is stated as 0.039 to
0.25 mg/kg. These PRGs for sediment and soil may not be achievable as a result of
upgradient, background sources of DDTR at the Ciba-Geigy Superfund site immediately
north of OU-2. DDTR concentrations at the Ciba-Geigy Superfund site of 1 to 3 mg/kg
did not require remediation. The OU-2 sediment and soil PRGs should be revised to be
consistent with upgradient, background conditions of 1 to 3 mg/kg that may migrate from
the Ciba-Geigy Superfund site. Olin recommends that USEPA revise the sediment and
soil DDTR PRGs to range from 1 to 3 mg/kg.
3. Page 6 - The DDTR PRG for forage fish tissue proposed by USEPA is 0.64 mg/kg. This
goal may not be achievable because of potential migration of DDTR from the BASF
facility immediately north of OU-2. Olin recommends a range of DDTR from 1.05 to 2.33
mg/kg in forage fish tissue which is consistent with the biota-sediment accumulation
relation with upgradient, background soil concentrations of DDTR of 1 to 3 mg/kg. The
DDTR fish tissue PRG of 0.64 mg/kg for OU-2 is also not consistent with the Ciba-Geigy
Remedial Goal of 1.5 mg/kg.
4. Page 6 - A PRG of 0.64 for DDTR in forage fish tissue proposed by USEPA is based on
a summary paper (Beckvar, et al., 2005) that uses fish species that are not native to the
southeastern United States. The PRG should be revised using species that are
expected to occur at OU-2, be consistent with background DDTR contributions, and be
consistent with the Remedial Goal for the upgradient Ciba-Geigy Superfund site. Olin
recommends a forage fish tissue remedial goal of 1.05 to 2.33 mg/kg and a
soil/sediment remedial goal of 1 to 3 mg/kg to be consistent with upgradient, background
conditions.
5. Page 6 - USEPA provides a Remedial Action Objective for restoration of surface water
to meet water quality standards. The ambient water quality criterion (AWQC) for
mercury is 0.012 |jg/L. Olin notes that compliance with the surface water AWQC will be
applied to filtered surface water at the point of discharge at the gate. The USEPA-
approved Feasibility Study (FS) for OU-2 indicates that the confirmation point for this
RAO is at the gate overflow. Overflow at the gate is representative of exposure
concentrations within OU-2; it also represents the quality of water exiting OU-2.
l
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June 19, 2013
6. Page 13 - Olin acknowledges USEPA's position on designating OU-2 sediments as "not
readily classifiable as principle threat wastes". However, it is Olin's position that the
mercury in sediment at OU-2 is a low level threat waste for the following reasons.
• OU-2 sediment containing mercury can be reliably contained via an in-situ cap.
• OU-2 sediment presents a low risk in the event of a release.
• OU-2 sediment exhibits low mobility.
• OU-2 sediment is near health-based levels.
A more detailed explanation for classification of the sediments at OU-2 as a low level
threat waste was submitted to USEPA in a letter dated August 24, 2012.
7. Page 13 - Olin concurs with USEPA's decision to determine the selected cap materials,
cap thickness, and the potential use of reactive materials during the remedial design.
References:
Beckvar, N., T.M. Dillon, and L.B. Read, 2005. Approaches for linking whole-body fish tissue
residues of mercury or DDT to biological effects thresholds. Environ Toxicol Chem.
24(8): 2094-2105.
2
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BASF
The Chemical Company
June 20, 2013
Via Certified and Electronic Mail
Ms. Beth Walden
Superfund Remedial Branch
U.S. Environmental Protection Agency
61 Forsyth Street
Atlanta, Georgia 30303
RE: Comments to Proposed Plan for Olin Mcintosh Operable Unit 2
Dear Ms. Walden:
BASF Corporation submits the following comments to the U.S. Environmental Protection
Agency's (EPA) Proposed Plan for Olin Mcintosh's Operable Unit 2 (OU-2). Specifically,
BASF opposes the proposed remedial goals for DDTr in OU-2.
BASF operates at the property adjacent and to the north of the Olin Mcintosh site. Under
the oversight of EPA and the Alabama Department of Environmental Management
(ADEM), BASF has been performing DDTr remediation work in the floodplain (BASF OU-3)
since 1995. The OU-3 remediation includes activities on both BASF and Olin floodplain
property. Beginning with the original Record of Decision through three consecutive 5-year
reviews, EPA management has consistently upheld the remedy chosen for the floodplain
remediation and the performance goal set for DDTr.
Over forty percent (approximately 89 acres) of Olin's OU-2 overlaps with BASF's OU-3.
Consistency in addressing DDTr is therefore necessary and critical to achieving a sound
remedy. However, in the Proposed Plan for the Olin site, EPA has recommended a set of
DDTr remedial goals for OU-2 that differ from BASF's OU-3 even within this overlapping
area. This inconsistency is troubling given that the existing remedy not only was developed
with input and approval from EPA, ADEM, and the NRD trustees, but has proven to be
successful and protective.
In addition, the Olin goals appear not to consider DDTr data collected during the process of
BASF's remediation. Instead, EPA has chosen to propose DDTr remedial goals for Olin's
OU-2 that are so low they may be technically impracticable to achieve.
In closing, the protection of health, safety and the environment is BASF's most important
responsibility. We care about our employees and we care about the communities in which
we operate. For this reason, BASF strongly believes that the Proposed Plan for the Olin
Mcintosh Operable Unit 2, and specifically the proposed DDTr remedial goals, must be
BASF Corporation
227 Oak Ridge Parkway
Toms River, NJ 08755
Tel. 732.914.2542
Steve.havlik@basf.com
-------
BASF
The Chemical Company
Ms. Beth Walden, USEPA
June 20, 2013
Page 2
based on sound scientific and technical principles, and consistent with prior agency
management decisions. The proposed DDTr remedial goals for Olin fall short of this mark.
BASF appreciates the opportunity to provide these comments. In addition, BASF requests
a meeting with EPA to discuss this letter. We will be in contact with the agency shortly to
schedule such meeting.
Stephen K. Havlik
Senior Remediation Specialist
CC: Franklin Hill (USEPA)
Richard Campbell (USEPA)
Carol Monell (USEPA)
Charles King (USEPA)
Sonja Favors (ADEM)
BASF Corporation
227 Oak Ridge Parkway
Toms River, NJ 08755
Tel. 732.914.2542
Steve.havlik@basf.com
Sincerely,
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3855 North Ocoee Street, Suite 200, Cleveland, TN 37312
(423) 336-4600 FAX: (423) 336-4166
June 19,2013
Ms. Beth Walden
Remedial Project Manager
U.S. Environmental Protection Agency
Atlanta Federal Center
61 Forsyth Avenue
Atlanta, Georgia 30303-8960
Re: Submittal of DDTR in Abiotic and Biotic Media
Mcintosh, Alabama
Dear Ms. Walden:
Olin Corporation (Olin) herein submits DDTR in Abiotic and Biotic Media, for the Olin Mcintosh
Plant Operable Unit 2 (OU-2), located in Mcintosh, Alabama. This document summarizes DDT
concentrations over time at OU-2 and describes how preliminary remediation goals (PRGs) were
calculated for sediment, soil, and fish tissue. Analytical results and PRG calculation methods are
based on the information provided in the Remedial Investigation Addendum (AMEC, 201 la), the
Updated Ecological Risk Assessment (ERA; AMEC, 2011b), and the Remedial Goal Options
(RGO) report (AMEC, 2012) for OU-2. This document also provides recommendations for
PRGs.
Please let me know if you have any questions. I can be reached at (423) 336-4388 or via e-mail
(kdroberts@olin.com).
Sincerely,
OLIN CORPORATION
Keith D. Roberts
Director, Environmental Remediation
cc: S. Favors - ADEM
C. A. Hunt - Olin
T. E. Stroth - Olin
L. D. O'Brien - Olin
C. E. Draper - AMEC
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June 19, 2013
OLIN MCINTOSH OPERABLE UNIT 2 (OU-2)
DDTR IN ABIOTIC AND BIOTIC MEDIA
The purpose of this document is to present changes in DDT concentrations over time at Olin
Mcintosh OU-2 and describe how preliminary remediation goals (PRGs) were calculated for
sediment, soil, and fish tissue. Analytical results and PRG calculation methods are based on
the information provided in the Remedial Investigation (Rl) Addendum (AMEC, 2011a), the
Updated Ecological Risk Assessment (ERA; AMEC, 2011b), and the Remedial Goal Options
(RGO) report (AMEC, 2012). This document also provides recommendations for PRGs.
DDT concentrations are reported as DDTr or DDTR. DDTr is a combination of the 4,4'-isomers
of DDT, DDE, and DDD. DDTr was analyzed in 1991 as part of the Rl and in 2008. DDTR,
which is the total of the 2,4'- and 4,4'-isomers of DDD, DDE, and DDT, was analyzed in
subsequent investigations in the 1990s, and in 2001 and 2009. The presence of DDTR is likely
a result of indirect discharges from the Ciba-Geigy Corporation (Mcintosh Plant) Superfund site,
(currently BASF property) located immediately north of OU-2. Olin did not manufacture DDT or
intermediate daughter products associated with DDTR.
DDTR CONCENTRATIONS AT OU-2 SEDIMENT, SOILS, AND WATER
Sediment
DDTr/DDTR concentrations in surficial sediment (0" to 6") are presented in Table 1A and Figure
1. Figure 1 also provides non-surficial sediment core data.
1991/1994: DDTr was analyzed in surficial sediment collected in 1991 and 1994. The 1991 and
1994 DDTr concentrations ranged from 0.272 to 63.5 milligrams per kilogram (mg/kg).
Generally, higher DDTr concentrations were detected in Round Pond. DDTr concentrations
decreased from north to south for these early Rl data. DDTR ranged from 0.536 to 177 mg/kg
based on the known ratio of DDTr to DDTR. A 95% upper confidence limit (UCL) of 5.84 mg/kg
was estimated for surficial sediment in the Basin and >177 mg/kg in Round Pond.
2001: DDTR concentrations ranged from 0.0893 to 64.8 mg/kg in the Basin and 2.20 to 26.0
mg/kg in Round Pond. The 95% UCL was 6.14 mg/kg for surficial sediment in the Basin and
19.5 mg/kg in Round Pond. Generally, higher concentrations were detected in Round Pond and
concentrations decreased from north to south.
2008/2009: DDTR concentrations ranged from 0.0144 to 2.72 mg/kg in surficial sediment in
2008/2009 in the Basin and from 0.117 to 0.226 mg/kg for the one location sampled in Round
Pond in 2008 and 2009. The DDTR concentrations in OU-2 decreased notably from 1991 to
2008/2009. The higher concentrations of DDTr/DDTR were detected in the southern portion of
the Basin in 2008 and 2009. This distribution represents a change from the DDTr distribution in
1991 and 2001. The current distribution of DDTR in sediment is depicted in Figure 2.
Floodplain Soils
DDTr/DDTR concentrations in floodplain soils are presented in Table 1B.
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June 19, 2013
1994/2001: DDTR concentrations ranged from 0.739 to 155 mg/kg with a 95% UCL of >155
mg/kg in 1994 based on 8 samples and a result of 15.1 mg/kg in 2001 for the one sample
location.
2010: DDTR was collected from locations throughout the OU-2 floodplain in 2010. DDTR
concentrations in surficial floodplain soils ranged from 0.00375 to 2.23 mg/kg with a 95% UCL of
1.2 mg/kg. Concentrations decreased from north to south, with the highest concentrations in
the northwest portion of the floodplain, immediately adjacent to Ciba-Geigy Corporation
(Mcintosh Plant) Superfund site. DDTR concentrations in the northwest are notably higher than
those in the eastern and southern portion of the floodplain. DDTR floodplain soil data from 2010
are presented in Figure 3.
Surface Water and Groundwater
DDTR was not detected in surface water collected from OU-2 in 1991. It was also not detected
in groundwater in 2008. DDTR is not a constituent of concern in surface water or groundwater.
DDTR CONCENTRATIONS AT OU-2 IN FISH TISSUE
Fish species present at OU-2 can be divided into two categories based on their function in the
ecosystem: forage fish and predatory fish.
Forage Fish
DDTR whole body concentrations in forage fish are presented in Table 2. This table lists the
DDTR concentrations in mosquitofish (Gambusia affinis) collected in 2001 and brook silversides
(.Labidesthes sicculus) and bluegill (Lepomis macrochirus) collected in 2010. Mosquitofish
concentrations were higher in Round Pond than in the Basin during the 2001 sample collection.
Fish tissue collection was based on the available fish species at the time of collection. DDTR in
the 2010 forage fish samples ranged from 0.878 to 1.82 mg/kg in brook silversides and 0.557 to
5.46 mg/kg in bluegill.
Predatory Fish
Predatory fish at OU-2 are represented by largemouth bass (Micropterus salmoides).
Largemouth bass DDTR tissue concentrations are presented in Table 3. Largemouth bass filet
concentrations ranged from 0.15 to 2.76 mg/kg. The DDTR mean in the Basin was 0.741 mg/kg
and DDTR mean in Round Pond was 2.22 mg/kg in 2001. Largemouth bass filet concentrations
ranged from 0.094 to 0.367 mg/kg with a mean of 0.166 mg/kg in 2010 in the Basin, a decrease
since 2001. Largemouth bass whole body concentrations ranged from 0.674 to 39.2 mg/kg with
a mean of 4.2 mg/kg in 2010 in the Basin. Forage fish and predatory fish were not collected in
Round Pond in 2010 due to low water levels. Comparisons cannot be made for DDTR from
2001 to 2010 for Round Pond, as a result.
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June 19, 2013
SEDIMENT DDTR PRG CALCULATION USING BSAF AND RATIO METHODS
Sediment BSAF/Ratio Methods
Aquatic insect and forage fish consumption was identified as the ecological risk driver for DDTR
for the little blue heron, belted kingfisher, and pied-billed grebe. The dietary composition of the
little blue heron, belted kingfisher, and pied-billed grebe includes a substantial component of
forage fish and aquatic insects. Preliminary remediation goals (PRGs) were calculated for
DDTR at OU-2 using the biota-sediment accumulation factor (BSAF) method.
DDTR is a lipophilic compound. The reported fish tissue DDTR concentrations were lipid-
normalized by dividing the reported DDTR concentrations by the fraction of lipids for each
sample. Sediment DDTR concentrations were also normalized by dividing the reported DDTR
concentrations by the average fraction of organic carbon (FOC) for the sediment samples.
Data pairing of fish and sediment samples is the first step in BSAF development. Guidance in
calculating the BSAF recommends that sediment samples across a typical foraging range be
collected and analyzed, and that the sediment samples should be representative of the
organism's immediate life history (Burkhard, 2009). Thus, appropriate tissue and sediment
sample pairs are collected within a narrow timeframe (i.e., the same year). The use of sediment
and tissue data across multiple years includes a time lapse between the exposed tissue and the
medium in which the tissue was exposed. Fish may have also lived in various areas of the
Basin during different life stages (i.e., juvenile vs. adult). Inclusion of data across multiple years
increases the uncertainty associated with the data pairing. The data pairings used for the PRG
development were generally for sediment and fish tissue samples collected within the same
year, with the exception of including 1991 data with the 1994 data. This deviation in the general
data pairing methodology was made because the coefficient of determination (R2) values
obtained during linear regression analysis increased with inclusion of the older sediment data.
Paired observations in each dataset were made by matching fish samples either with collocated
sediment samples or with sediment samples within a typical home range for each fish type. The
data pairings are summarized below:
• Pairing 1991 and 1994 sediment with fish collected in 1991 and 1994
• Pairing 2001 sediments with fish collected in 2001
• Pairing 2008 sediments with fish collected in 2008
Analytical results for sediments within the foraging range of the organism were averaged in the
data pairings to determine a representative concentration. Sediment core samples in the 0 to 6
inch depth interval were treated as individual samples when averaging sediments at a location.
Analytical results for fish tissue were averaged within a sample station if multiple samples were
collected from a single location or area within the same year.
Predatory fish home ranges were assumed to be a quadrant of the Basin or the entirety of
Round Pond. Forage fish home ranges were assumed to be a circle with a radius of 400 feet
and centered on a sample station (AMEC, 2012). The 400-foot-radius circle was selected
because it provided coverage in all directions and accounted for the uncertainty associated with
the fish sample collection area in relation to the overall home range. All sediment data from
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June 19, 2013
Round Pond were paired with the forage fish data in Round Pond instead of using a 400-foot
radius.
Sediments in each reference area were averaged to generate one representative concentration
for the reference sediments. The average sediment concentration was paired with the average
fish concentration for each reference area to generate one data point for each reference area.
The reference areas were limited to one data pairing so that the OU-2 BSAF analysis would be
representative of conditions in OU-2, rather than areas outside OU-2.
PRGs were also calculated using the ratio method. PRGs were calculated by dividing the
average fish tissue concentration by the average sediment concentration. Home ranges were
not considered in the ratio method. The results of the BSAF and ratio analysis indicated that the
BSAF method was more appropriate than the ratio method for calculating sediment PRGs for
OU-2 (AMEC, 2012).
Sediment PRG Analysis
The DDTR sediment-fish data pairs were plotted in Microsoft® Excel. Average sediment
concentrations were plotted along the x-axis, and the associated average fish concentrations
were plotted along the y-axis. A regression trend line, a R2 value, and a p-value were calculated
by Excel and placed on each graph. The goal was to find a model equation with an R2 value
greater than 0.7 and a p-value less than 0.05. Multiple regression models were generated for
DDTR in forage fish. Separate regression analyses were conducted for DDTR in forage fish
using normalized and non-normalized data. The R2 values ranged from 0.44 to 0.78 with p-
values ranging from 0.0001 to 0.02 for DDTR in sediment. Regression results which produced
R2 and p-values that met the goals were carried forward in the PRG calculation process.
Normalization of the data resulted in higher R2 values and lower p-values than use of the non-
normalized data. The power curve generated from the normalized data was the only DDTR
regression equation that met the USEPA R2 goal of 0.7 with a R2 of 0.78 and an acceptable p-
value of 0.0001. The power equation using normalized data was the only model included in the
DDTR PRG development. The linear model and the non-normalized data model did not meet
the USEPA R2 goal of 0.7. The use of a regression equation for normalized DDTR requires that
fish data be normalized using the average lipid fraction for all samples, and the resulting
sediment concentrations be de-normalized. De-normalization of sediments was accomplished
by multiplying the normalized sediment concentration by the average FOC of all samples.
The ratio method was also used to calculate DDTR PRGs to provide a range of sediment PRGs
for each receptor. The ratio method is not dependent on R2 values or p-values, and can be
used for PRG development when regression analysis does not indicate a strong correlation
between the sediment and tissue data (as is indicated by R2 values less than 0.7 and p-values
greater than 0.05). R2 values and p-values for the ratio method were not generated because
the meaning of these two statistical terms for best fit lines is not equivalent to the meaning of
these two terms for the ratio method. The ratio method was not carried forward in the PRG
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June 19, 2013
development for DDTR in sediment because the power model in the BSAF regression analysis
met the USEPA goal for the R2 and p values.
Sediment PRGs
The range of DDTR PRGs developed to be protective of ecological receptors ingesting forage
fish in OU-2 is summarized below. This PRG range comprises the NOAEL- to LOAEL-based
risks for DDTR in sediment. The PRGs based on the geometric mean of the NOAEL- and
LOAEL-based risks for DDTR in sediment are also discussed below.
DDTR Sediment PRGs Protective of Ecological Receptors Ingesting Forage Fish (Figure 4):
• 0.69 mg/kg dw (NOAEL) to 1.19 mg/kg dw (LOAEL) for the belted kingfisher (RME;
assuming a diet consisting of fish and other dietary items and an area use factor of
50%);
• 0.28 mg/kg dw (NOAEL) to 0.38 mg/kg dw (LOAEL) for the belted kingfisher (assuming
a highly conservative diet of 100% fish and an area use factor of 100%);
• 0.37 mg/kg dw (NOAEL) to 1.2 mg/kg dw (LOAEL) for the pied-billed grebe;
• 0.48 mg/kg dw (NOAEL) to 0.71 mg/kg dw (LOAEL) for the little blue heron; and
• 1.33 mg/kg dw (NOAEL) to 2.07 mg/kg dw (LOAEL) for the great blue heron.
The belted kingfisher and the little blue heron are the most sensitive receptors to DDTR in
sediments. The geometric mean DDTR sediment PRGs are as follows:
• 0.91 mg/kg dw for the belted kingfisher (RME; assuming a diet consisting of fish and
other dietary items and an area use factor of 50%):
• 0.33 mg/kg dw for the belted kingfisher (assuming a highly conservative diet of 100%
fish and an area use factor of 100%);
• 0.58 mg/kg dw for the little blue heron;
• 0.66 mg/kg dw for the pied-billed grebe; and
• 1.7 mg/kg dw for the great blue heron.
A Remedial Action Objective was developed for DDTR in only forage fish because ecological
receptors associated with risk from DDTR have a diet consisting mostly of forage fish. The
ecological receptors exposed to DDTR in fish do not typically consume predatory fish.
SOIL DDTR PRG CALCULATION USING BAF AND RATIO METHODS
Soil BAF/Ratio Methods
The development of soil PRGs has been designed to be protective of insectivorous birds that
may forage in the OU-2 floodplains. The Carolina wren was selected as the receptor for the
evaluation of risk to insectivorous birds at OU-2 (AMEC, 2011b). The dietary consumption of
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June 19, 2013
the wren was assumed to consist exclusively of invertebrates. The bioaccumulation factor
(BAF) method was used to pair insect tissue samples with associated floodplain soil samples for
DDTR. The BAF approach is similar to the BSAF approach used in the sediment PRG
evaluation. Data pairs were established by matching invertebrate samples with floodplain soil
samples within 400 feet of the invertebrate collection site. Invertebrate tissue concentrations
were graphed against average floodplain soil concentrations, and site-specific regression
equations relating the tissue concentrations to surface soil concentrations were developed. The
target invertebrate tissue concentration was then determined by back calculation of terrestrial
risk equations. The target invertebrate tissue concentration was entered into the site-specific
regression equation to obtain a corresponding PRG for soil.
The ratio method was also used to provide a range of soil PRGs for OU-2. PRGs were
calculated by dividing the average invertebrate tissue concentration by the average floodplain
soil concentration. Home ranges were not considered in the ratio method.
The results of the BAF and ratio analysis indicated that the ratio method was more appropriate
than the BAF regression analysis for calculating soil PRGs for DDTR for OU-2, as discussed
below.
Soil PRG Analysis
DDTR floodplain soil PRGs were evaluated using the ratio method with normalized and non-
normalized data and this method was selected as the most representative. Floodplain soil
PRGs for DDTR were also estimated using the linear and power regression equations for the
BAF regression analysis using normalized and non-normalized data for informational purposes
only to document the evaluation. The BAF linear and power regression analysis was not used
to estimate PRGs because it did not produce acceptable R2 and p values. The PRGs were
estimated by back-calculating to a target DDTR invertebrate tissue concentration associated
with a hazard index (HI) of 1 for insectivorous avian receptors using the ratio method.
Soil PRGs
DDTR floodplain soil PRGs were evaluated using the ratio method with lipid normalized data.
Data groupings of different combinations of insect types (flying insects, crawling insects, and
spiders) were used to provide a range of potential soil DDTR PRGs (Figure 5). The soil PRGs
using normalized data were:
• 0.032 mg/kg dw (NOAEL) to 0.047 mg/kg dw (LOAEL) for flying insects.
• 0.076 mg/kg dw (NOAEL) to 0.11 mg/kg dw (LOAEL) for flying insects, crawling insects,
and spiders (1994 data excluded).
• 0.11 mg/kg dw (NOAEL) to 0.17 mg/kg dw (LOAEL) for crawling insects and spiders.
• 0.16 mg/kg dw (NOAEL) to 0.23 mg/kg dw (LOAEL) for crawling insects.
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June 19, 2013
• 0.21 mg/kg dw (NOAEL) to 0.31 mg/kg dw (LOAEL) for flying insects, crawling insects,
and spiders (1994 data included).
DDTR soil PRGs protective of insectivorous birds ranged from 0.032 mg/kg dw (NOAEL) to 0.31
mg/kg dw (LOAEL) for the Carolina wren. The geometric mean soil PRG range is 0.039 mg/kg
dw to 0.25 mg/kg dw for the Carolina wren.
The DDTR PRG for floodplain soils was developed using highly conservative exposure
assumptions. The DDTR LOAEL HI for the Carolina wren was 1.4 in the updated ERA (AMEC,
2011 b), which is slightly above the target of 1. The conservative nature of the risk equations
would indicate the DDTR HI of 1.4 is likely overestimated for the Carolina wren. This adds to
the level of uncertainty for the need for a DDTR PRG for floodplain soils.
USEPA'S DDTR PRG RECOMMENDATIONS
USEPA recommends a DDTR PRG for OU-2 sediments of 0.33 to 1.7 mg/kg in the Proposed
Remedial Action Plan (PRAP; USEPA, 2013). The USEPA proposed DDTR PRG for OU-2
floodplain soils is stated in the PRAP as 0.039 to 0.25 mg/kg (USEPA, 2013). The DDTR PRG
for forage fish tissue proposed in the PRAP is 0.64 mg/kg (USEPA, 2013).
The PRGs for sediment and soil may not be achievable as a result of upgradient, background
sources of DDTR at the Ciba-Geigy Corporation (Mcintosh Plant) site immediately north of OU-
2. Residual DDTR concentrations at the Ciba-Geigy Corporation (Mcintosh Plant) site of 1 to 3
mg/kg did not require additional remediation by USEPA. The likelihood exists that upgradient,
background conditions of 1 to 3 mg/kg may migrate from the Ciba-Geigy Corporation (Mcintosh
Plant) site. Sediment and soil samples collected from OU-2 in 2009 and 2010 show that the
DDTR concentrations at OU-2 are also within this same range (1 to 3 mg/kg).
The DDTR fish tissue PRG of 0.64 mg/kg for OU-2 is based on a literature summary paper
(Beckvar, et al., 2005). The PRG proposed by USEPA is the lower end of the range of values
presented in the paper for a variety of fish species. This variety of fish species contains several
that are not native to the southeastern United States. This PRG is also not consistent with the
Ciba-Geigy Corporation (Mcintosh Plant) goal of 1.5 mg/kg (USEPA, 2006). The forage fish
tissue PRG proposed by USEPA also may not be achievable because of potential migration of
DDTR from the Ciba-Geigy Corporation (Mcintosh Plant) site immediately north of OU-2. The
PRG should be revised using species that are expected to occur at OU-2, be consistent with
background DDTR contributions, and be consistent with the Remedial Goal for the upgradient
Ciba-Geigy Superfund site. USEPA typically allows for background concentrations to be
considered in selection of a PRG.
CONCLUSION AND RECOMMENDATIONS
DDTR is a unique constituent of concern at OU-2 because its source does not originate from
within the Olin Property. Manufacturing activities at the Olin Plant did not include DDTR. The
primary release mechanism for DDTR is migration of sediments and soils containing DDTR from
the Ciba-Geigy Corporation (Mcintosh Plant) Superfund site located immediately north of OU-2.
Floodplain soil and sediment collected from the 1990s at OU-2 show a distinct DDTR migration
pattern. These data provide evidence that DDTR migrated south from the Ciba-Geigy
Corporation (Mcintosh Plant) property onto OU-2.
7
-------
June 19, 2013
The Ciba-Geigy Corporation (Mcintosh Plant) property has released DDTR to OU-2 in the past
and has the potential to continue to release DDTR at residual concentrations of 1 to 3 mg/kg.
The site-specific, "background" concentration for OU-2, as a result, is 1 to 3 mg/kg. USEPA
typically uses site-specific background as a consideration in the selection of PRGs. USEPA
should consider the PRG selected for fish tissue at the Ciba-Geigy site of 1.5 mg/kg for DDTR.
Conditions in the floodplain immediately north of OU-2 are very similar to those at OU-2 such
that a different and more stringent PRG for OU-2 soils in comparison to the Ciba-Geigy
Superfund site is not justifiable.
Olin recommends that USEPA revise the sediment and soil DDTR PRGs to range from 1 to 3
mg/kg. Olin also recommends a forage fish tissue DDTR PRG range of 1.05 to 2.33 mg/kg,
which is consistent with the biota-sediment accumulation relationship with upgradient,
background sediment/soil concentrations of DDTR of 1 to 3 mg/kg. This fish tissue PRG range
is also consistent with the PRG selected for the Ciba-Geigy Superfund Site.
REFERENCES
AMEC, 2011a, Part 1 Remedial Investigation Addendum and Enhanced Sedimentation Pilot
Project Annual Report, Year 2 Results. Revision 2. Operable Unit 2, Mcintosh, Alabama.
November 14,
AMEC, 2011b, Part 2 Updated Ecological Risk Assessment. Revision 2. Operable Unit 2,
Mcintosh, Alabama. November 14.
AMEC, 2012. Remedial Goal Option Report for the Development of Preliminary Remediation
Goals in Sediment and Floodplain Soils, Revision 3. Operable Unit 2, Mcintosh,
Alabama. July 6.
Beckvar, N., T.M. Dillon, and L.B. Read, 2005. Approaches for linking whole-body fish tissue
residues of mercury or DDT to biological effects thresholds. Environ Toxicol Chem.
24(8): 2094-2105.
Burkhard, L. 2009. Estimation of Biota Sediment Accumulation Factor (BSAF) from Paired
Observations of Chemical Concentrations in Biota and Sediment. U.S. Environmental
Protection Agency, Ecological Risk Assessment Support Center, Cincinnati, OH.
EPA/600/R-06/047.
USEPA, 2006. Second Five-Year Review Report for Cibay-Geigy Chemical Superfund Site,
Mcintosh, Washington County, Alabama. USEPA Region 4 Science and Ecosystem
Division. September.
USEPA, 2013. Proposed Plan Olin Mcintosh Operable Unit 2, Washington County, Alabama.
May 22.
8
-------
Table 1A. DDTR Concentrations in Surficial Sediment
Basin
Round Pond
1991
1994
2001
2008
2009
1994
2001
2008
2009
n
15
6
45
4
4
6
12
1
1
Minimum Concentration (mg/kg)
0.536
1.41
0.0893
0.0144
0.0784
5.86
2.20
0.117
0.226
Maximum Concentration (mg/kg)
12.2
6.18
64.8
0.639
2.72
177
26.0
0.117
0.226
95% UCL
5.84
6.14
1.16
>177
19.5
0.226
Table 1B. DDTR Concentrations in Floodplain Soil
1994
2001
2010
n
8
1
21
Minimum Concentration (mg/kg)
0.739
15.1
0.00375
Maximum Concentration (mg/kg)
155
15.1
2.23
95% UCL
>155
--
1.2
Notes:
DDTR - sum of 2,4'- and 4,4'-DDD, DDE, and DDT. One-half the reporting limit is used in the summary calculations for non-detects.
mg/kg - milligram per kilogram
n - number of samples
95% UCL - 95 percent upper confidence limit
- - 95% UCL not calculated for one sample
-------
Table 2. Forage Fish Tissue DDTR Concentrations.
Basin by Quadrant
NW Quadrant
NE Quadrant
SW Quadrant
SE Quadrant
Basin
Round Pond
2001
2010
2001
2010
2001
2010
2001
2010
2001
2010
2001
2010
n
3
-
9
-
-
-
3
-
15
-
6
-
Mosquitofish1
Minimum Concentration (mg/kg)
1.65
-
0.99
-
-
-
1.29
-
0.99
-
6.54
-
Maximum Concentration (mg/kg)
1.88
-
2.05
-
-
-
1.44
-
2.05
-
10.8
-
Average Concentration (mg/kg)
1.77
-
1.38
-
-
-
1.34
-
1.45
-
8.44
-
n
-
1
-
1
-
1
-
1
-
4
-
-
Brook
Minimum Concentration (mg/kg)
-
0.878
-
1.0
-
1.82
-
0.907
-
0.878
-
-
Silversides1
Maximum Concentration (mg/kg)
-
0.878
-
1.0
-
1.82
-
0.907
-
1.82
-
-
Average Concentration (mg/kg)
-
0.878
-
1.0
-
1.82
-
0.907
-
1.15
-
-
n
-
5
-
5
-
5
-
5
-
20
-
-
Bluegill2
Minimum Concentration (mg/kg)
-
1.01
-
0.557
-
0.625
-
0.675
-
0.557
-
-
Maximum Concentration (mg/kg)
-
2.16
-
4.44
-
2.64
-
5.46
-
5.46
-
-
Average Concentration (mg/kg)
-
1.74
-
2.1
-
1.69
-
1.86
-
1.85
-
-
Notes:
DDTR - sum of 2,4'- and 4,4'-DDD, DDE, and DDT. One-half the reporting limit is used in the summary calculations for non-detects.
mg/kg - milligram per kilogram
n - number of samples
NE - northeast
NW - northwest
SE - southeast
SW - southwest
- - not collected
1 whole body, composite samples
2 whole body, individual samples
-------
Table 3. Predatory Fish Tissue DDTR Concentrations.
Basin by Quadrant
NW Quadrant
NE Quadrant
SW Quadrant
SE Quadrant
Basin
Round Pond
2001
2010
2001
2010
2001
2010
2001
2010
2001
2010
2001
2010
Filet
Filet
WB
Filet
Filet
WB
Filet
Filet
WB
Filet
Filet
WB
Filet
Filet
WB
Filet
Filet
WB
Largemouth
Bass
n
2
5
10
4
5
10
5
10
1
5
10
7
20
40
3
Minimum Concentration (mq/kq)
0.715
0.159
0.696
<0.05
0.0968
1.66
0.0937
1.25
0.927
0.095
0.674
0.15
0.094
0.674
1.38
Maximum Concentration (mq/kq)
1.42
0.346
39.2
1.43
0.154
3.85
0.253
9.37
0.927
0.367
3.68
1.43
0.367
39.2
2.76
Average Concentration (mg/kg)
1.07
0.203
8.24
0.5
0.121
2.68
0.16
3.88
0.927
0.182
2.39
0.741
0.166
4.2
2.22
Notes:
DDTR - sum of 2,4'- and 4,4'-DDD, DDE, and DDT. One-half the reporting limit is used in the summary calculations for non-detects.
mg/kg - milligram per kilogram
n - number of samples
NE - northeast
NW - northwest
SE - southeast
SW - southwest
WB - whole body
- - not collected
-------
DDTr Historical Concentration Boundaries
ROUND
POND
BASIN
0.324 Concentration in mg/kg
Legend
DDTr Historical Concentration Boundaries
INLET
CHANNEL
contour
15 mg/kg
0.324 Concentration in mg/kg
Source: JJSDA/FSA - Aerial Photography Field,Office
WCC, 1994. Additional Ecological Studies of OU-2.
Figure .4:7.^1
2009 DDTR Sediment Sample Location and Results
ROUND
ROND
DDTr =0.40
DDTR =1.14
OU2B-SED-303DC-09
DDTfZ=.0739
DDTR =2.68
INLET
channel
Olin Mcintosh OU 2
2009 Sediment Sample Locations and DDTR Results
Comparison to Historical Results
Prepared by/Date:
BWH -11/06/09
Figure
Number:
Checked by/Date:
CED -11/06/09
Project Number:
6107090035
-------
¦a
x
E
6
3
O)
o
¦4—1
c
o
c
o
a>
O)
o
c
o
Q.
c
5
.o
re
Q_
ROUND
POND
DDTR< 0.051
OU2R-SED-101DC-09
¦DDTR^OTillfcB I
bI?RDC=R3945
OU2B-SED-4Q2C-09
DDTr=0.019
DDTR =0.060
w SDCR8
DDTR = 0.557
OU2B-SED-103DC-09
¦DDJflg)tl-38li
DDTR =0.305
SDCR3
DDTR = 2.21
SOlJ2B-SED-303DC-09
¦DDjTfl=T0739
¦DDTR =2.68
PlNHEiU
CHANNEL
Source: USDA/FSA - Aerial Photography Field Office -2009
Olin Mcintosh OU-2
2009 DDTR Isocontour Map (0-4" Surficial and 0-12" Core)
With Mercury Remedial Footprint ( > 1.6 to 10.7 mg/kg Mercury)
Prepared by/Date:
SLW- 4/03/12
Figure
Number;
Checked by:
CED- 4/03/12
Project Number:
6107120036
-------
c <
O 5
= <6
wm
OU2B-FPSS1-10
2.23
OU2B-FPSS6-10
B 0*216 J
OU2B-FPSS8-10
0.295 'J i
OU2B-FPSS4-10
0.0933 J
OU2B-FPSB1 -10-0-1
. 2.21 \J' •
OU2B-FPSB3-10-0-1
0.0485 J
OU2B-FPSS3-10
0.329^;;' ¦
OU2B-FPSS7-10
0.0553
OU2B-FPSB2-10-0-1
0.0871 fjlt
OU2B-FPSS9-10
0.0131 *J
OU2B-FPSS10-10
OU2B-FPSB4-10-0-1
0.0098 J
BASIN
OU2B-FPSS11-10
0.035
OU2B-FPSS12-10
0.00558 fJ:
INLET
OU2B-FPSB6-10-0-1
<0.002
Legend
2010 Inundated Floodplain Soil (Sediment) Sample Location
O 2010 Floodplain Soil Sample Location
- - - Approximate 6' Water Elevation
Notes:
DDTR totals calculated using zero for non-detected congeners
Results in milligrams per kilogram
FPSB : Soil Boring Location (0-1 inch)
FPSS : Surficial Soil (0-1 inch) Location
J : Estimated Concentration
Olin Mcintosh OU-2
Floodplain Soil DDTR Results
Prepared by/Date:
THP - 3/21/11
Figure
Number:
Checked by/Date:
CED- 3/21/11
Source: USDA/FSA-Aerial Photography FieldOffice.-2006,
Project Number:
6107110036
-------
Figure 4
DDTR Target Sediment Concentrations Protective of Receptor
Based on Risk from Forage Fish
+
Belted Kingfisher (Highly Conservative Exposure)
0.28 mg/kg - 0.38 mg/kg
R2: > 0.70; p-values: < 0.05
Recommended PRG (+): 0.33 mg/kg
Belted Kingfisher (Reasonable Maximum Exposure)
0.69 mg/kg -1.19 mg/kg
R2: > 0.70; p-values: < 0.05
Recommended PRG (+): 0.91 mg/kg
+
Pied-Billed Grebe
0.37 mg/kg -1.2 mg/kg
R2: > 0.70; p-values: < 0.05
Recommended PRG (+): 0.66 mg/kg
+
Little Blue Heron
0.48 mg/kg - 0.71 mg/kg
R2: > 0.70; p-values: < 0.05
Recommended PRG (+): 0.58 mg/kg
Great Blue Heron
1.33 mg/kg - 2.07 mg/kg
R2: > 0.70; p-values: < 0.05
Recommended PRG (+): 1.67 mg/kg
+
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2
Range of DDTR PRGs for Sediment (mg/kg)
Indicates the geometric mean PRG for the receptor.
PREPARED BY/DATE: MKB 3/28/12
CHECKED BY/DATE: EFC 3/28/12
-------
FIGURE 5
DDTR Target Soil Concentrations Protective of the Carolina Wren (Normalized Data)
Flying Insects, Crawling Insects, and Spiders, 1994 Includpi
0.21 mg/kg- 0.31 mg/kg
Geomean (+): 0.25 mg/kg
+
+
Flying Insects, Crawling Insects, and Spiders, 1994 Excluded
0.076 mg/kg - 0.11 mg/kg
Geomean (+): 0.091 mg/kg
+ Flying Insects
0.032 mg/kg - 0.047 mg/kg
Geomean (+): 0.039 mg/kg
+
Crawling Insects
0.16 mg/kg - 0.23 mg/kg
Geomean (+): 0.19 mg/kg
+
Crawling Insects & Spiders
0.11 mg/kg - 0.17 mg/kg
Geomean (+): 0.14 mg/kg
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18 0.19 0.20 0.21 0.22 0.23 0.24 0.25 0.26 0.27 0.28 0.29 0.30 0.31
Range of DDTR PRGs for Soil (mg/kg)
+ Indicates the geometric mean PRG for the invertebrate grouping (Table 4-6).
Prepared By: NSR 4/16/12
Checked By: EFC 4/16/12
-------
APPENDIX 3.2 - COMMENT LETTERS AFTER PUBLIC COMMENT PERIOD
-------
Robert J. Bentley
Governor
Alabama Department of Environmental Management
adem.alabama.gov
1400 Coliseum Blvd. 36110-2400 • Post Office Box 301463
Montgomery, Alabama 36130-1463
{334)2717700 « FAX (334) 271-7950
September 18, 2013
CERTIFIED MAIL # 91 7199 9991 7030 3429 6219
Lance R. LeFleur
Director
ADEM
Ms. Beth Walden
Remedial Project Manager
U.S. Environmental Protection Agency
Atlanta Federal Center
61 Forsyth Street
Atlanta, GA 30303-8960
RE: ADEM Review and Concurrence:
Draft Record of Decision for OU2 dated September 2013
Dear Ms. Walden:
The Department has reviewed the draft submittal of the ROD for Olin Corporation's Mcintosh
facility. Based on our review, the Department concurs with the selected remedy, in-situ capping,
with the following notifications:
1. The Department has concerns with the preliminary remedial goal (PRG) for the
contaminant of concern (COC) DDTr. The value, outlined in the ROD, differs from the
PRG currently established for portions of the floodplain previously designated as
protective in OU-2. ADEM recommends establishing a consistent cleanup standard for
the entire floodplain.
2. The proposed PRG for DDTr in the draft ROD for the Olin facility may not be
appropriately calculated due to the use of the historical data applied to generate the
remediation values. The use of historical data that does not account for remedial actions
completed that improve the bioavailable concentration of DDTr may yield a remediation
value that is not accurately calculated.
Please note that on September 16, 2013, the Department provided additional comments on the
ROD electronically to address general grammatical concerns. If you have any questions
concerning this matter, please contact Mrs. Sonja B Favors at 334-279-3067.
Sincerely,
Land Division
PDD/SBF/nbf
Birmingham Bnmch
110 Vulcan Road
Birmingham, AL 35209-4702
(205) 942-6168
(205) 9411603 (FAX)
Decatur Branch
2715 Sandlfn Road, S.W.
Decatur, Al 35603-1333
(256)353-1713
(256) 340-9359 (FAX)
^'Yr &
-7
Mobile Branch
Moblte-Coastal
*
*
2204 Perimeter Road
4171 Commanders Drive
•
Mobile, AL 36615-1131
Mobile, AL 36615-1421
,v
(251) 450-3400
(251) 432-6533
(251) 479-2593 (FAX)
(251) 432 6598 (FAX)
-------
Olin
3855 North Ocoee Street
Suite 200
Cleveland, TN 37312
(423) 336-4007
cmrichards@olin.com
Curt M. Richards
Corporate Vice President,
Environment, Health & Safety
Mr. A. Stanley Meiberg
Acting Regional Administrator
Region 4
U.S. Environmental Protection Agency
Atlanta Federal Center
61 Forsyth Avenue
Atlanta, Georgia 30303-8960
Re: USEPA's Proposed Remediation Goals for DDTR
Olin Mcintosh Operable Unit (OU) 2, Mcintosh, Alabama
Dear Mr. Meiberg:
Olin Corporation (Olin) has tried to understand the rationale regarding the proposed remediation
goals for the 2,4'- and 4,4'-isomers of DDT, DDE, and DDD (collectively, DDTR) for the Mcintosh
OU-2 Superfund Site in Mcintosh, Alabama. Our requests to meet with USEPA Region 4 Agency
officials prior to the issuance of the Record of Decision (ROD) to discuss this issue have not been
successful. DDTR is a unique Chemical of Concern (COC) at OU-2 because its source does not
originate from within the Olin property. The primary release mechanism for DDTR is migration of
sediments and soils containing DDTR from the Ciba-Geigy Corporation (Mcintosh Plant)
Superfund Site (currently BASF property) located immediately north of OU-2. Historic and
current DDTR data provide evidence that DDTR migrated south from the Ciba-Geigy site onto OU-
2.
Off-site, upgradient concentrations were not considered in the selection of DDTR remedial goals
for OU-2. (This information is summarized in the attached DDTR Summary). Olin has concerns
that soil and sediment runoff containing DDTR will re-contaminate the in-situ cap specified in the
Proposed Remedial Action Plan so that remedial goals at OU-2 are not achievable. The Alabama
Department of Environmental Management has also expressed concerns about the preliminary
remedial goal in their letter to Beth Walden, USEPA Remedial Project Manager, dated September
18, 2013. (This letter is attached). Olin requests that USEPA explain how activities at the Ciba-
Geigy Superfund Site will affect meeting the remedial goals at Olin's OU-2 prior to the issuance of
the ROD.
Olin Corporation
-------
Mr, A, Stanley Meiberg
November 21, 2013
Page 2
Please let me know if you have any questions; I am available to discuss this concern at your
convenience. I can be reached at (423) 336-4007 or via e-mail (cmrichards@olin,com).
Sincerely,
GUN CORPORATION
Cui tis M. Richards
Vice President, Environmental Health and Safety
Enclosures (2)
Olin Corporation
-------
POSITION PAPER FOR FUTURE DISCUSSION
DDTR GOALS AT OU-2
The purpose of this document is to state Olin Corporation's (Olin's) opposition to the proposed remedial
goal for the 2,4'- and 4,4'-isomers of DDT, DDE, and DDD (collectively, DDTR) in floodpiain soil, sediment,
and forage fish at the Mcintosh OU-2 Superfund Site, in Mcintosh Alabama. The U.S. Environmental
Protection Agency (USEPA) prepared the Proposed Remedial Action Plan [FRAP] for the Olin Mcintosh
Operable Unit 2 (OU-2) and identified the primary site-related constituents of concern (COCs) as
mercury and hexachlorobenzene (HCB), The PRAP proposed remediation goals for DDTR, in addition to
proposing remediation goals for mercury and HCB. Olin provided comments on the PRAP requesting
revision of the DDTR remediation goals to consider site-specific background, as provided in the USEPA-
approved OU-2 Feasibility Study (November 2012) and Remedial Goal Option Report for the
Development of Preliminary Remediation Goals in Sediment and Floodpiain Soils (July 2012). USEPA
indicated that the DDTR remediation goals for these media would not be revised. Olin takes exception to
the implementation of these risk-based DDTR remediation goals without consideration of site-specific
background concentrations and cites inconsistencies with goals provided for an adjacent site, as
discussed below,
DDTR is a unique COC at OU-2 because its source does not originate from within the Oiin property.
Manufacturing activities at the Olin Mcintosh Plant did not include DDT or intermediate daughter
products associa ted with DDTR. The primary release mechanism for DDTR is migration of sediments and
soils containing DDTR from the Ciba-Geigy Corporation (Mcintosh Plant) Superfund site (currently BASF
property) located immediately north of OU-2. Historic and current DDTR data provide evidence that
DDTR migrated south from the Ciba-Geigy site onto OU-2. The Ciba-Geigy site represents the site-
specific background for OU-2 and has the potential to continue to release DDTR at residual
concentrations of 1 to 3 mg/kg, which is above the USEPA proposed goals for OU-2. The site-specific,
background concentration for OU-2, as a result, is 1 to 3 mg/kg.
USEPA's PRAP for OU-2 recommends remedial goals based solely on conservative risk based calculations
and does not consider background or goals for the adjacent site. USEPA's selected remedial goal ranges
are 0.33 to 1.7 mg/kg for sediment, 0.039 to 0,25 mg/kg for floodpiain soil, and 0.64 mg/kg for fish
tissue. USEPA has also indicated that the preferred remedial alternative, in-situ capping, will require the
design of a cap that effectively isolates both mercury (primary COC) and DDTR.
USEPA typically uses site-specific background as a consideration in the selection of remediation goals.
However, site-specific background is not considered in the PRAP. The remedial goals are less than the
site-specific background concentration of 1 to 3 mg/kg DDTR in sediments and floodpiain soils and the
Ciba-Geigy remedial goal selected for forage fish tissue (1.5 mg/kg), Conditions in the floodpiain
immediately north of OU-2 are very similar to those at OU-2. Migration of background DDTR at the Ciba-
Geigy site onto a cap at OU-2 has the potential to re-contaminate the cap, once placed.
1
-------
Olin recommends the following options, in combination or separately, to address the DDTR remediation
goals at OU-2:
1. Select remedial goals for floodplain soils/sediments that are consistent with the USEPA-
approved Remedial Goal Option Report for the Development of Preliminary Remediation Goals in
Sediment and Floodplain Soils and Feasibility Study, The remedial goal range recommended in
the report and approved by USEPA was 1 to 3 mg/kg for sediments and floodplain soils. Select a
remedial goal for forage fish that is consistent with that for the Ciba-Geigy site (i.e., 1.5 mg/kg).
2. Acknowledge that the preferred alternative, in-situ capping, in addition to addressing site-
specific COCs (mercury and HCB), will also be effective for DDTR in OU-2 sediment. Cap
performance and effectiveness would be based on mercury and HCB, not DDTR,
Olin is prepared to proceed with remediation activities as described in the PRAP with the
implementation of the above option(s).
2
-------
Lance R. LeFleur
Director
Robert J. Bentley
Governor
Alabama Department of Environmental Management
adem.oiabHma.gov
1400 Coliseum Blvd. 36110-2400 ¦ Post Office Box 301463
Montgomery, Alabama 36130-1463
(334) 271-7700 « FAX (334) 271-7950
September 18,2013
CERTIFIED MAIL it 91 7199 9991 7030 3429 6219
Ms, Beth Walden
Remedial Project Manager
U.S. Environmental Protection Agency
Atlanta Federal Center
61 Forsyth Street
Atlanta, GA 30303-8960
RE: ADEM Review and Concurrence:
Draft Record of Decision for OU2 dated September 2013
Dear Ms. Walden:
The Department has reviewed the draft submittal of the ROD for Olin Corporation's Mcintosh
facility. Based on our review, the Department concurs with the selected remedy, in-situ capping,
with the following notifications:
1, The Department has concerns with the preliminary remedial goal (PRO) for the
contaminant of concern (COC) DDTr, The value, outlined in the ROD, differs from the
PRG currently established for portions of the floodplain previously designated as
protective in OU-2. ADEM recommends establishing a consistent cleanup standard for
the entire floodplain.
2. The proposed PRG for DDTr in the draft ROD for the Olin facility may not be
appropriately calculated due to the use of the historical data applied to generate the
remediation values. The use of historical data that does not account for remedial actions
completed that improve the bioavailablc concentration of DDTr may yield a remediation
value that is not accurately calculated.
Please note that on September 16, 2013, the Department provided additional comments on the
ROD electronically to address general grammatical concerns. If you have any questions
concerning this matter, please contact Mrs. Sonja B Favors at 334-279-3067.
Sincerely,
Phillip D. Davis, Chief
Land Division
PDD/SBF/nbf
Birmingham Branch
110 Vulcan Road
Birmingham, AL 35209-4702
(205)942-6168
1205) 941-1603 (FAX)
Decatur Branch
2715Sandlin Road, S.W.
Decatur, AL 35603-1333
(256)353-1713
1256} 340-9359 (FAX)
r
(251)479-2593 (FAX)
2204 Perimeter Road
Mobile, AL 36615-1131
(251)450 3400
MoWIe Branch
MoWte-Coasta!
4171 Commanders Drive
Mobile, At 36615-1421
(251) 432-6533
(251) 432-6598 (FAX}
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APPENDIX 3.3 - PUBLIC MEETING TRANSCRIPT MAY 22, 2013
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Public Meeting 1
1
2
3
4
5
6
U.S. ENVIRONMENTAL PROTECTION AGENCY
7
8
PROPOSED PLAN
9
10
olin Mcintosh operable unit 2
11
12
PUBLIC MEETING
13
14
WASHINGTON COUNTY, ALABAMA
15
16
MAY 22, 2013
17
18
19
20
21
22
23
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Public Meeting
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1 U.S. ENVIRONMENTAL PROTECTION AGENCY
2
3 PROPOSED PLAN
4
5 PUBLIC MEETING
6
7 olin Mcintosh operable unit 2
8
9 WASHINGTON COUNTY, ALABAMA
10
11 MAY 22, 2013
12
13
14
15
16 INTRODUCTION:
17 KYLE BRYANT, COMMUNITIES INVOLVEMENT
18 COORDINATOR ENVIRONMENTAL
19 PROTECTION AGENCY, REGION 4
2 0 PRESENTER:
21 BETH WALDEN, PROJECT MANAGER
22 ENVIRONMENTAL PROTECTION AGENCY
2 3 WASTE MANAGEMENT DIVISION
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1 INTRODUCTION
2
3 MR. BRYANT: First I'd like to
4 say welcome this evening. My name is Kyle
5 Bryant. I am the Communities Involvement
6 Coordinator from the Environmental
7 Protection Agency, Region 4, out of Atlanta
8 assigned to the Olin Mcintosh site.
9 The first order of business, I
10 hope everyone who comes in has signed our
11 sign-in sheet in the back. If you have
12 not, please take a moment to do so before
13 you leave. It's right there on the left
14 corner of that table. So we can keep in
15 touch with you for future correspondence.
16 The occasion this evening is for
17 a proposed plan public meeting to discuss
18 Operable Unit 2. And you will hear a
19 presentation by the Regional Project
20 Manager, Beth Walden, who is seated right
21 here to my right.
22 And we have other people from
23 the agency, from EPA, Region 4, here in the
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1 audience with us this evening as well as
2 our colleagues from the state, if you have
3 any subsequent questions about what you're
4 going to hear about tonight.
5 Just a brief word on this
6 process. We have business cards on the
7 back table so if you want to grab a couple
8 of them and an ink pen that we've also
9 provided back there, you can jot down your
10 questions related to the presentation or
11 the Proposed Plan. And make sure they get
12 in my hands before you leave at the end of
13 the day so that we can compile them and
14 give those to the Project Manager so she
15 can respond to those in a timely manner.
16 This is the beginning of our
17 3 0-day comment period on the Proposed Plan
18 so it officially starts this evening. So,
19 even if it takes you a little bit longer to
2 0 formulate your questions or you want to
21 review the documents further, please take a
22 copy of the Proposed Plan on the back table
23 with you. And she has a business card on
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1 the table and I'll also provide my contact
2 information so you can get in touch with
3 either of us to forward your comments or
4 questions. Okay?
5 We also have a court reporter
6 here. We're required by the National
7 Contingency Plan to have a court reporter
8 record the meeting proceeds. So would you
9 like to introduce yourself?
10 COURT REPORTER: I'm Patricia
11 Taylor with Freedom Court Reporting.
12 MR. BRYANT: With that, I'll
13 introduce our Remedial Project Manager,
14 Beth Walden. You may begin.
15
16 PRESENTATION
17
18 MS. WALDEN: Good evening.
19 Thanks for coming out tonight. I have been
20 working on the Olin OU-2 site for about six
21 or seven years and we have reached a point
22 in our Superfund process where we are
23 recommending a cleanup action for the
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1 basin. So, tonight we're going to go over
2 some background for the site, the studies
3 we've done to date, what the contaminants
4 of concern are, the process we use to
5 figure out what is driving the cleanup, the
6 different cleanup alternatives that we've
7 taken a look at and then EPA's preferred
8 remedy.
9 So the site is divided into two
10 operable units. And if you want to take a
11 look in your Proposed Plan it might be a
12 little easier to see.
13 Operable Unit 1. When a site is
14 complex or we're ready to make a decision
15 on one part of the site, we will divide the
16 site up organizationally, administratively,
17 to deal with the existing environmental
18 problems. So the plant area is what we
19 call Operable Unit 1.
20 Operable Unit 2 is actually the
21 basin; the floodplain and the old waste
22 water ditch that went from the facility to
23 Olin basin. So here's an aerial photo of
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1 the plant area, which I'm sure most of you
2 in the room are familiar with. The waste
3 water ditch used to drain here and go into
4 the Olin basin. And this is obviously the
5 Tombigbee River.
6 So just to highlight some of the
7 features. In 2006, Olin built a berm
8 around much of the floodplain, which is
9 about two hundred acres. The basin is
10 about a 70-acre lake. In the middle of the
11 lake is about a 40-foot depth from where
12 the old Tombigbee River channel used to cut
13 through the floodplain. So, the facility
14 is up here in what we call the uplands.
15 This is Round Pond. And Olin built a gate
16 that they used to manage the water level in
17 the lake.
18 So, EPA and Olin have been
19 involved in the site for a number of years;
20 began the investigations in 1990. And in
21 1994, they actually came up with a remedy
22 for OU-1, which involved treatment of the
2 3 groundwater. They upgraded a landfill
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1 cover. And under their active plant
2 management they've actually closed a number
3 of units that either had solid waste or
4 hazardous waste in them. That actually was
5 completed in about 2001. All the
6 construction for what we call Operable Unit
7 1.
8 And then from 2001 to present
9 we've been looking at Operable Unit 2 or
10 focusing on Operable Unit 2.
11 We actually in 1994 when we made
12 the selection for the OU-1 remedy there
13 were investigations going on in OU-2 and
14 they were primarily ecological data
15 collection. And as I said, in 2001
16 construction of OU-1 was finished.
17 In 2004-2005, Olin took the
18 initiative and built a berm, as I showed
19 you earlier, and it has a gate structure
20 and it's around 100-150 acres or so of the
21 floodplain.
22 And between 2006-2010, we
23 collected at lot more data.
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1 And in 2011-12, we finalized the
2 Remedial Investigation and Feasibility
3 Study Reports.
4 So just to give you an idea of
5 the type of work that we were doing over
6 the last ten, fifteen years: There has
7 been sediment collection, surface water;
8 measurement of how much sediment was coming
9 into the system with the berm in place; a
10 debris survey to take a look at fallen
11 trees and what was on the bottom of the
12 lake bed; ground water investigation. In
13 fact, to take a look at the sediment
14 deposition in the lake you had to have
15 OSHA-trained divers to dive down into the
16 bottom of the lake and take a look at the
17 sediment pens. We've had CLAMS out there
18 to take a look at mercury uptake into the
19 CLAMS. We've taken cores of the bottom of
20 the basin; pore water sampling, which is
21 between the sediment and the water; and we
22 also took a look at how old the
23 contamination was, at what depth, and tried
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1 to figure out and correlate how many inches
2 a year sediment were getting into the
3 system.
4 Wind suspension in the lake.
5 You have winds obviously that come across
6 the top of the lake that cause water
7 movement, which we believe may be causing
8 some of the sediment from not settling out.
9 We took samples of the floodplain soils.
10 We've looked at mercury specifically
11 because mercury is unique in that it has a
12 biological influence that causes the
13 mercury to stay in the biota and stay
14 mobile within the sediment column.
15 We've taken samples of fish,
16 insects, monthly surface water sampling to
17 take a look at the influences of the wind,
18 as well as the -- the sediment transport
19 modeling. Took a look at when the sediment
20 comes into the system, does it stay in the
21 system. And what we have found is we have
22 three primary contaminants of concern:
23 That is mercury, hexachlorobenzene, and
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1 what we refer to as DDTR. And it is the
2 result of the waste water from the Olin
3 plant into the OU-2 basin, and floodwaters
4 coming in and mixing the contamination
5 around and it1s moving across the
6 floodplains. DDTR also is a contaminant of
7 concern from indirect discharges from BASF,
8 or used to be known as CIBA.
9 What we have found is that there
10 is no current risk because Olin has site
11 security measures in place. If there were
12 no security measures in place there would
13 be an unacceptable risk to people eating
14 the fish. There is also an ecological risk
15 to fish-eating birds, insect-eating birds,
16 from both the sediment and the soil.
17 The green, the larger area,
18 represents the footprint that will need to
19 be addressed with any type of remedy.
2 0 The lighter green hatched area
21 represents an area that we need to take
22 some additional soil samples primarily for
23 DDT because we haven't sampled this area in
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1 a very long time.
2 The orange cross-hatched area
3 represents an area that we want to do
4 further sampling in, primarily for the
5 hexachlorobenzene. These two areas will be
6 addressed by whatever the remediation is
7 that we choose. And EPA is recommending
8 the capping alternative. So those areas
9 would be evaluated as part of the capping.
10 So we looked at a number of
11 different remedial technologies and decided
12 for mercury-contaminated sites, the most
13 obvious technologies are capping, dredging
14 and basically doing nothing and letting the
15 contamination over time become more dilute
16 or to actually degrade. The no-action
17 alternative is actually an EPA-required
18 alternative to look at.
19 The difference in alternative
20 2A, 2B and 2C is really whether or not you
21 de-water the basin and cap on dry land or
22 apply a subaqueous cap within the lake.
23 And, so, we dealt with different ways of
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1 looking at the number of acres to see if it
2 made sense to de-water it.
4 dredging. Which is basically removing all
5 the contaminated sediment and either
6 placing it onsite in a landfill or shipping
7 it offsite.
9 placing the material all over the bottom of
10 the basin as well any parts of the flood-
11 plain that need to be addressed. A capping
12 material like a sand or a clay or some
13 other type of amendment to go with the sand
14 or native soil. And then a habitat layer
15 that you want to jump start. Once you cap
16 something you want to jump start the
17 biological activity again.
18 So the cost for capping for 2A
19 is about 15 million. 2B is 15.6. 2C is 17
20 million.
21 If you dredge, you're looking at
22 a cost of about 55 million to 70 million,
23 depending on whether you leave it onsite or
3
And lastly, we looked at
8
Capping would basically involve
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1 ship it offsite.
2 When we compare the alternatives
3 we look at nine criteria and you could
4 probably see them better in your handout.
5 The first two are what we call
6 the threshold criteria. The remedy has to
7 be protective of human health in the
8 environment and it has to comply with
9 federal or state regulations.
10 The next five criteria are what
11 we call the balancing criteria. We look at
12 the long-term effectiveness. Meaning in
13 the long term, in a hundred years, is this
14 still going to be a remedy that's going to
15 work? We try to reduce the toxicity
16 mobility, or volume.
17 Short-term effectiveness: When
18 you actually apply the remedy are there any
19 short-term risks that -- like for instance,
20 with dredging, obviously if you dredge, the
21 short-term risks are you're removing all of
22 the sediment and habitat for, you know, the
23 critters, so the speak, or the fish. So
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1 that has an immediate short-term impact.
2 Capping has an impact, not as
3 severe; because as you're placing the
4 material, it's not killing everything that
5 you're putting material on because they can
6 move through the water columns.
7 And then we look at cost. We
8 compare the cost and the benefit of one
9 alternative compared to another.
10 And the last two are the State
11 acceptance and community acceptance. And
12 those are the two things that we take a
13 look at in the next thirty days based on
14 the comments we get.
15 EPA is recommending Alternative
16 2A because we feel it is the best balance
17 of the five balancing criteria. It does
18 meet protection of human health in the
19 environment. We expect that the fish
20 should recover in the next ten years after
21 the cap is implemented and we consider it
22 more cost effective than the dredging
23 alternative.
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1
And that is an example of the
2 barge that is one of the techniques for
3 placing the material over the contaminated
4 sediment.
6 and Remedy Selection Stage. So as Kyle
7 mentioned earlier, we're going to take a
8 look at the comments we receive. We're
9 going to write a Record of Decision that
10 basically outlines the remedy selection,
11 what I've just walked you through. But I
12 have to write a responsiveness summary so
13 if I receive comments during that period I
14 have to technically respond to those and
15 those also go in the Record of Decision.
16 After the Record of Decision, we
17 will basically negotiate -- In this case we
18 have one potentially responsible party and
19 that's Olin. We actually have potentially
20 CIBA as well for the DDT. So we will send
21 a letter out and say "are you guys going to
22 do the work?" They'll say yes or no. We
23 write an administrative order; it's lodged
5
So, we're at the Proposed Plan
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1 in the court. And from that point on we're
2 back into the technical world of remedial
3 design documents where they lay out their
4 plans for how they're actually going to
5 build the cap. We're going to talk about
6 the frequency of monitoring. Because once
7 you leave a hazardous substance in place
8 like mercury, we will be doing 5-year
9 reviews for as long as it does not allow
10 for unrestricted access.
11 So, basically, we'll be out here
12 for a very long time monitoring to see
13 whether the work that we have done is
14 effective.
15 And that concludes the formal
16 part of this presentation. If you guys
17 have any questions I'm more than happy to
18 answer them. And we'll stick around also
19 if you're more comfortable asking questions
2 0 when we're done. That's it. Thank you for
21 coming out tonight.
22
2 3 END OF PROCEEDINGS
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1 CERTIFICATE
2
3 STATE OF ALABAMA )
4 COUNTY OF CONECUH )
5
6 I hereby certify that the above and
7 foregoing transcript of proceedings was
8 taken down by me in machine shorthand, and
9 the questions and answers thereto were
10 transcribed by means of computer-aided
11 transcription, and that the foregoing
12 represents a true and correct transcript of
13 the proceedings given by said witness upon
14 said hearing.
15 I further certify that I am neither
16 of counsel nor of kin to the parties to the
17 action, nor am I in anywise interested in
18 the result of said cause.
19 I further certify that I am duly licensed
2 0 by the Alabama Board of Court Reporting as
21 a Certified Court Reporter as evidenced by
22 the ACCR number following my name below.
23
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1
2
PATRICIA L. TAYLOR, CCR.
3
CCR# 363, Expires 9/30/13
4
Commissioner for the.
5
State of Alabama at Large.
6
My Commission Expires: 12/31/16
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
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WORD INDEX
< 9 >
74, 78 18:6, 8
beginning 4:76
9 19:3
another. 15:9
believe 10:7
< 1 >
answer 17:78
below. 18:22
1 6:73
< A >
answers 18:9
benefit 15:8
1. 6:79 8:7
a 3:77, 78 4:27
any 4:3 14:78
berm 7:7 8:78
100-150 8:20
6:70, 77 9:9
anywise 18:77
9:9
12 19:6
10:2, 77 12:7
apply 12:22
best 15:76
13 19:3
13:22 15:72
14:78
BETH 2:27 3:20
15 13:79
16:7, 27 18:27
are 5:22
5:74
15.6 13:79
about 7:9, 70
area 6:78 7:7
better 14:4
16 19:6
17:5
11:20, 27, 23
between 9:27
17 13:79
acceptance
12:2, 3
biological 10:72
1990 7:20
15:77, 77
area, 11:77
13:77
1994 7:27 8:77
access. 17:70
areas 12:5, 8
biota 10:73
ACCR 18:22
around 7:8 11:5
birds 11:75
< 2 >
acres 7:9 8:20
as 4:7 10:78
birds, 11:75
2 1:70 2:7 3:78
13:7
15:2 18:20
bit 4:79
6:20 8:9
across 10:5
asking 17:79
Board 18:20
2. 8:70
action 5:23
assigned 3:8
bottom 9:77, 76,
2001 8:5, 8, 75
18:77
at 13:3, 27 14:77
79 13:9
2004-2005 8:77
active 8:7
at. 12:78
brief 4:5
2006 7:7
activity 13:77
Atlanta 3:7
BRYANT 2:77
2006-2010 8:22
additional 11:22
audience 4:7
3:3, 5 5:72
2011-12 9:7
addressed 11:79
build 17:5
2013 1:76 2:77
12:6 13:77
< B>
built 7:7, 75 8:78
22 1:76 2:77
administrative
back 3:77 4:7,9,
business 3:9
2A 12:20 13:78
16:23
22 17:2
4:6, 23
15:76
administratively,
background 6:2
by 18:20, 27
2B 12:20 13:79
6:76
balance 15:76
2C 12:20 13:79
aerial 6:23
balancing 14:77
after 15:20
15:77
call 6:79 7:74
< 3 >
again. 13:77
barge 16:2
8:6 14:5, 77
30 19:3
AGENCY 1:6
based 15:73
can 4:75 15:5
30-day 4:77
2:7, 79, 22 3:7,23
BASF, 11:7
cap 12:27, 22
31 19:6
ALABAMA 1:74
basically 12:74
13:75 15:27 17:5
363 19:3
2:9 18:3, 20 19:5
13:4, 8 16:70, 77
capping 12:8, 73
all 13:4
17:77
13:8, 77, 78 15:2
< 4 >
allow 17:9
basin 6:7, 27, 23
capping. 12:9
4 2:79 3:7, 23
also 4:8 9:22
7:4,9 9:20 11:3
card 4:23
40-foot 7:77
17:78
12:27 13:70
cards 4:6
alternative 12:8,
be 11:73, 79
case 16:77
< 5 >
77, 78, 79 15:9, 75
12:5 14:7
cause 10:6
55 13:22
alternative. 15:23
because 10:77
cause. 18:78
5-year 17:8
alternatives 6:6
bed 9:72
causes 10:72
14:2
been 5:79 7:78
causing 10:7
< 7>
amendment 13:73
9:7
CCR 19:3
70 13:22
and 4:73 8:73,
before 3:72
CCR. 19:2
70-acre 7:70
20 10:23 12:74,
began 7:20
Certified 18:27
23 15:77 16:6,
begin. 5:74
certify 18:6, 75,
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79
contaminants
degrade 12:76
ENVIRONMENTAL
channel 7:72
6:3 10:22
depending 13:23
1:6 2:7, 78, 22
choose 12:7
contaminated
deposition 9:74
3:6 6:77
CIBA 16:20
13:5 16:3
depth 7:77 9:23
EPA 3:23 7:78
CIBA. 11:8
contamination
design 17:3
12:7 15:75
CLAMS 9:77, 19
9:23 11:4 12:75
de-water 12:27
EPA-required
clay 13:12
Contingency 5:7
13:2
12:77
cleanup 5:23
COORDINATOR
difference 12:79
EPA's 6:7
6:5, 6
2:78 3:6
different 6:6
evaluated 12:9
closed 8:2
copy 4:22
12:77, 23
even 4:79
colleagues 4:2
cores 9:79
dilute 12:75
evening 3:4, 76
collected 8:23
corner 3:74
discharges 11:7
4:7, 78
collection 8:15
correct 18:72
discuss 3:77
evening. 5:78
9:7
correlate 10:7
ditch 6:22 7:3
evidenced 18:27
column. 10.14
correspondence.
dive 9:75
example 16:7
columns. 15:6
3:75
divers 9:75
existing 6:77
come 10:5
cost 13:78, 22
divide 6:75
expect 15:79
comes 3:10
15:7, 8, 22
divided 6:9
Expires 19:3, 6
10:20
could 14:3
DIVISION 2:23
comfortable
counsel 18:76
do 12:3 16:22
< F>
17:79
COUNTY 1:74
documents 4:27
facility 6:22 7:73
coming 5:19 9:8
2:9 18:4
17:3
fact 9:73
11:4 17:27
couple 4:7
does 15:77
fallen 9:70
comment 4:77
court 5:5, 7, 70,
doing 9:5 12:74
familiar 7:2
comments 5:3
77 17:7 18:20, 27
17:8
Feasibility 9:2
15:74 16:8, 73
cover 8:7
drain 7:3
features 7:7
Commission 19:6
criteria 14:3, 6,
dredge 13:27
federal 14:9
Commissioner
70, 77 15:77
14:20
feel 15:76
19:4
critters 14:23
dredging 12:73
fifteen 9:6
COMMUNITIES
cross-hatched
13:4 14:20 15:22
figure 6:5 10:7
2:77 3:5
12:2
driving 6:5
finalized 9:7
community 15:77
current 11:70
dry 12:27
finished. 8:76
compare 14:2
cut 7:72
duly 18:79
First 3:3, 9 14:5
15:8
fish 11:74 14:23
compared 15:9
< D>
< E >
15:79
compile 4:73
data 8:74
E 18:7
fish, 10:75
completed 8:5
data. 8:23
earlier 8:79 16:7
fish-eating 11:75
complex 6:74
date 6:3
easier 6:72
five 14:70 15:77
comply 14:8
day 4:73
eating 11:73
flood- 13:70
computer-aided
days 15:73
ecological 8:74
floodplain 6:27
18:70
DDT 11:23 16:20
11:74
7:8, 73 10:9
concern 6:4 11:7
DDTR 11:7, 6
effective 15:22
floodplain. 8:27
concern: 10:22
deal 6:77
effective. 17:74
floodplains 11:6
concludes 17:75
dealt 12:23
effectiveness
floodwaters 11:3
CONECUH 18:4
debris 9:70
14:72, 77
focusing 8:70
consider 15:27
decided 12:77
either 5:3 8:3
following 18:22
construction 8:6,
decision 6:74
13:5
footprint 11:78
76
16:9, 76
environment
for 3:76 7:22
contact 5:7
Decision. 16:75
14:8 15:79
11:22 12:72
contaminant 11:6
16:2 17:70, 72, 20
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foregoing 18:7,
hear 3:78 4:4
7:20 8:73
longer 4:79
77
hearing. 18:74
involve 13:8
long-term 14:72
formal 17:75
here 3:27 5:6
involved 7:19,22
look 6:7, 77
formulate 4:20
17:77
INVOLVEMENT
9:70, 73, 76, 78,
forward 5:3
hexachlorobenzen
2:77 3:5
22 10:77, 79
found 10:27 11:9
e 10:23 12:5
is 6:73 7:8,9,14
12:78 14:3, 77
Freedom 5:11
highlight 7:6
9:20 11:70 12:6
15:7, 73 16:8
frequency 17:6
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Freedom Court Reporting, Inc 877-373-3660
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Public Meeting 23
monitoring 17:6,
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Freedom Court Reporting, Inc 877-373-3660
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Public Meeting 24
samples 10:9, 15
11:22 13:72
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Freedom Court Reporting, Inc 877-373-3660
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Public Meeting
25
WASTE 2:23
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11:2
water 6:22 7:3,
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Freedom Court Reporting, Inc
877-373-3660
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