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Crane, J. L. 1992. Abstract and Table of Contents to "Baseline Human Health Risk Assessment: Ashtabula River, Ohio, Area of Concern," EPA-905-R92-007. Athens, Ga.: Environmental Research Laboratory.

by

Judy L. Crane
ASCI Corporation
Athens, Georgia 30613

Project Officer
Robert B. Ambrose, Jr.
Environmental Research Laboratory
Athens, Georgia 306713

ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTRACTION AGENCY
ATHENS, GEORGIA 30613

 

Baseline Human Health Risk Assessment: Ashtabula River, Ohio, Area Of Concern

The information in this document has been funded wholly or in part by the United States Environmental Protection Agency under Contract Number 68-C1-0012 to ASCI Corporation. It has been subject to the Agency's peer and administrative review, and it has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement of recommendation for use by the U.S. Environmental Protection Agency.

Table of Contents

1. EXECUTIVE SUMMARY
1.1 OVERVIEW
1.2 STUDY AREA
1.3 EXPOSURE ASSESSMENT
1.4 RISK ASSESSMENT
1.4.1 Determination of Risk
1.4.2 Noncarcinogenic Risks
1.4.3 Carcinogenic Risks
1.4.4 Uncertainties

2. INTRODUCTION

3. ASHTABULA RIVER AREA OF CONCERN
3.1 ENVIRONMENTAL SETTING
3.2 CONTAMINATION PROBLEMS
3.3 RECREATIONAL USES
3.4 CONTAMINATION OF FISH
3.4.1 Routes of Contamination
3.4.2 Fish and Wildlife Advisories
3.5 WATER SUPPLY
3.6 HUMAN HEALTH CONCERNS

4. RISK ASSESSMENT FRAMEWORK
4.1 CONCEPT OF RISK
4.2 RISK FRAMEWORK

5. EXPOSURE ASSESSMENT
5.1 EXPOSURE PATHWAYS
5.2 DATA USED IN THE EXPOSURE ASSESSMENT
5.2.1 Data Sources
5.2.2 Data Review
5.2.3 Data Sets
5.3 EXPOSURE ASSESSMENT
5.3.1 General Determination of Chemical Intakes
5.3.2 Intakes: Ingestion of Contaminated Fish

6. TOXICITY ASSESSMENT
6.1 TOXICITY VALUES
6.2 LIMITATION 6-1

7. BASELINE RISK CHARACTERIZATION FOR THE ASHTABULA RIVER AOC
7.1 PURPOSE OF THE RISK CHARACTERIZATION STEP
7.2 QUANTIFYING RISKS
7.2.1 Determination of Noncarcinogenic Risks
7.2.2 Determination of Carcinogenic Effects
7.3 HUMAN HEALTH RISKS IN THE ASHTABULA RIVER AOC
7.3.1 Typical and Reasonable Maximum Exposures
7.3.1.1 Noncarcinogenic Risks
7.3.1.2 Carcinogenic Risks
7.3.2 Subsistence Anglers

8. CHARACTERIZATION OF QUALITATIVE UNCERTAINTIES
8.1 INTRODUCTION
8.2 QUALITATIVE LIST OF UNCERTAINTIES

8.2.1 Data Compilation and Evaluation
8.2.2 Exposure Assessment
8.2.3 Toxicity Values
8.2.4 Risk Characterization
8.3 SUMMARY

REFERENCES

APPENDIX A: Importance of other Complete Exposure Pathways in the Ashtabula River Area of Concern

APPENDIX B: Human Toxicity Estimates for Contaminants Present in the Ashtabula River Area of Concern


PREFACE

This risk assessment was prepared as part of the Assessment and Remediation of contaminated Sediments (ARCS) program coordinated by the U.S. EPA Great Lakes National Program Office. The work by ASCI Corporation was completed under contract no. 68-C1-0012 with the U.S. EPA Environmental Research Laboratory-Athens by Judy Crane, Ph.D. under the supervision of James L. Martin, Ph.D., P.E., ASCI Site Manager. This work was performed through the U.S. EPA Center for Exposure Assessment Modeling, Mr. Robert Ambrose, Jr., P.E., Manager.

FOREWORD

Risk assessment has been defined as the characterization of the probability of adverse effects from human and ecological exposures to environmental hazards. Risk assessments are quantitative, chemical-oriented characterizations that can use statistical and biological models to calculate numerical estimates of risk to human health or the environment. The concept of risk assessment is a cornerstone on which the U.S. Environmental Protection Agency builds programs to confront pollution problems in air, water, and soil under the direction of Congressional mandates. One such mandate is the Clean Water Act, which includes a directive to the Agency to study the control and removal of toxic pollutants in the Great Lakes, with emphasis on removal of contaminants from bottom sediments. Charged with performing this study is EPA's Great Lakes National Program Office (GLNPO) located in Chicago, IL. GLNPO administers the Assessment and Remediation of Contaminated Sediments (ARCS) program to examine the problem of contaminated sediments using a multidisciplinary approach involving engineering, chemistry, toxicology, modeling, and risk assessment.

In support of GLNPO, the Environmental Research Laboratory-Athens began a series of studies under the ARCS program that will culminate in baseline risk assessment for each of five Great Lakes Areas of Concern (AOC)--Buffalo River, NY, Grand Calumet River, IN, Saginaw River, MI, Ashtabula River, OH, and Sheboygan River, WI. This report describes a baseline human health risk assessment for the population within the Sheboygan River AOC. The assessment, which is based on available environmental data, is designed to provide a conservative estimate of carcinogenic and noncarcinogenic risks to human health under the baseline, no-action alternative.

Rosemarie C. Russo, Ph.D.
Director
Environmental Research Laboratory
Athens, Georgia.

ABSTRACT

The Assessment and Remediation of Contaminated Sediments (ARCS) program, a 5-year study and demonstration project relating to the control and removal of contaminated sediments from the Great Lakes, is being coordinated and conducted by the U.S. Environmental Protection Agency's (EPA) Great Lakes National Program Office (GLNPO). As part of the ARCS program, baseline human health risk assessments are being performed at five Areas of Concern (AOCs) in the Great Lakes region. The Ashtabula River, located in northeastern Ohio, is one of these AOCs.

In this report, exposure and risk assessment guidelines, developed for the EPA Superfund program, have been applied to determine the baseline human health risks associated with direct and indirect exposures to sediment-derived contaminants in the Ashtabula River AOC. These risks were estimated for noncarcinogenic (e.g., reproductive toxicity, teratogenicity, liver toxicity) and carcinogenic (i.e., probability of an individual developing cancer over a lifetime) effects. 


CHAPTER 1

EXECUTIVE SUMMARY

1.1 OVERVIEW

The Assessment and Remediation of Contaminated Sediments (ARCS) program, a 5-year study and demonstration project relating to the control and removal of contaminated sediments from the Great Lakes, is being coordinated and conducted by the U.S. Environmental Protection Agency's (EPA) Great Lakes National Program Office (GLNPO). As part of the ARCS program, baseline human health risk assessments are being performed at five Areas of Concern (AOCs) in the Great Lakes region. The Ashtabula River, located in northeastern Ohio, is one of these AOCs.

In this report, exposure and risk assessment guidelines, developed for the EPA Superfund program, have been applied to determine the baseline human health risks associated with direct and indirect exposures to sediment-derived contaminants in the Ashtabula River AOC. These risks were estimated for noncarcinogenic (e.g., reproductive toxicity, teratogenicity, liver toxicity) and carcinogenic (i.e., probability of an individual developing cancer over a lifetime) effects under different exposure scenarios.

1.2 STUDY AREA

The lower 3.2 km of the Ashtabula River and the Ashtabula Harbor have been severely impacted by industrial pollution, especially from contaminant loads transported into the river from Fields Brook, a Superfund site. Dredging of the federal navigation channel was stopped in 1964 due to severe contamination problems in the channel and to a lack of agreement among several agencies on how to safely dispose of the dredged sediments. Consequently, sediments have built up in the lower river to the point where it is becoming increasingly difficult for people with draft boats to navigate the river.

The contamination and sedimentation problems in this area have been of concern to the International Joint Commission (IJC); the IJC designated this region as an AOC in 1987. In response, the Ohio EPA has nearly completed the Stage One Remedial Action Plan (RAP) to identify contamination problems in the Ashtabula River AOC (Ohio EPA, 1991).

Within the AOC, the Ashtabula River is bordered by nine marinas and yacht clubs in the small city of Ashtabula. The lower river is used by recreational boaters and charter boat operators as an access point to Lake Erie. Sport fishing is very popular in the Ashtabula Harbor and in the nearshore Lake Erie area. The Ohio Department of Health and Ohio EPA issued a fish advisory in 1983 recommending that no fish caught in the river from the 24th St. Bridge to the harbor mouth be eaten (Woodward-Clyde Consultants, 1991). Despite these warnings, some people still fish in the AOC.

1.3 EXPOSURE ASSESSMENT

This assessment focused on only one pathway by which residents of the lower Ashtabula River were likely to be exposed to sediment-derived contaminants: the consumption of contaminated fish. Other exposure pathways were determined to be either incomplete (e.g., ingestion of sediments) or insignificant in terms of risk (e.g., ingestion of surface water during infrequent swimming events).

Woodward-Clyde Consultants (WCC) conducted the most recent survey (1990) of contaminant levels in fish inhabiting the Ashtabula River AOC. In this study, 12 carp , 16 small/large mouth bass, and 16 bluegill were collected from four sites in the AOC and were analyzed for a variety of contaminants. Data obtained from composite samples of fish collected from two of the sites were used in the exposure assessment: 1) the Ashtabula River just downstream from Fields Brook (3 carp , 2 large mouth bass, and 11 bluegills), and 2) the Ashtabula Harbor (4 carp , 1 small mouth plus 3 large mouth bass, and 5 bluegills). The carp were analyzed as whole fish while the other two species were analyzed as skin-on fillets. The collection and data analysis of the fish appears to have gone through a rigorous QA/QC program at WCC. Thus, the data were deemed usable for this baseline risk assessment.

Noncarcinogenic and carcinogenic risks were estimated for three different exposure scenarios: typical (average), reasonable maximum (i.e., the maximum exposure that is reasonably expected to occur at a site), and subsistence exposures. The subsistence pathway was chosen for a small segment of the population that may be relying on the consumption of fish from the area for their main source of protein. Different consumption rates were applied to each scenario (Table 1.1), and it was assumed that only fish collected and consumed from the Ashtabula River AOC were contaminated. In addition, the exposure duration varied with the exposure scenario. Typical exposures were assumed to occur over a period of 9 years; reasonable maximum and subsistence exposures were assumed to occur over a period of 30 years. Noncarcinogenic effects were averaged over the same time period as the exposure duration, whereas carcinogenic effects were averaged over a lifetime (i.e., 70 years). For all three exposure scenarios, exposures were determined for each chemical and added for each pathway. This assumption of additivity did not account for any synergistic or antagonistic effects that might occur among chemicals.

Several heavy metals and organic compounds that were detected in some or all of the fish samples were included in the exposure assessment (i.e., chromium, copper, mercury, silver, zinc, polychlorinated biphenyls (PCBs), 1,1,2,2-tetrachloroethane, tetrachloroethene, and trichloroethene). In addition, noncarcinogenic and/or carcinogenic toxicity values were either available or under renew for this set of contaminants. Thus, the exposure and toxicity information could be integrated into the risk assessment.

1.4 RISK ASSESSMENT

1.4.1 Determination of Risk
This baseline risk assessment did not characterize absolute human health risks, rather it identified potential sources of unacceptable risks. Risk estimates were determined for both noncarcinogenic and carcinogenic end points.

Noncarcinogenic effects were evaluated by comparing an exposure level over a specified time period with a reference dose (RfD)[1] derived from a similar exposure period (otherwise known as a hazard quotient (HQ)). Thus, HQ = exposure level/RfD. An HQ value of less than 1 indicates that exposures are not likely to be associated with adverse noncarcinogenic effects. HQ values between 1 and 10 may be of concern, particularly when additional significant risk factors are resent (e.g., other contaminants at levels of concern) (USEPA, 1988a). The sum of more than one HQ value for multiple substances and/or multiple exposure pathways is re resented by the Hazard Index (HI).

Carcinogenic risks were estimated as the incremental probability of an individual developing cancer over a lifetime as a result of exposures to potential carcinogens. This risk was computed using average lifetime exposure values that were multiplied by the oral slope factor[2] for a particular chemical. The resulting carcinogenic risk estimate generally represents an upper-bound estimate, because slope factors are usually based on upper 95th percentile confidence limits. Carcinogenic effects were summed for all chemicals in an exposure pathway. This summation of carcinogenic risks assumed that intakes of individual substances were small, that there were no synergistic or antagonistic chemical interactions, and that all carcinogens produced the same effect (i.e., cancer). The EPA believes it is prudent public health policy to consider actions to mitigate or minimize exposures to contaminants when estimated excess lifetime cancer risks exceed the 10[-5] to 10[-6] range, and when noncarcinogenic health risks are estimated to be significant (USEPA, 1988a).

1.4.2 Noncarcinogenic Risks
Noncarcinogenic risks, as represented by the Hazard Index (HI), were below levels of concern (i.e., less than 1) for most of the typical and reasonable maximum exposure scenarios (Table 1.2). For fish collected from the Ashtabula Harbor, only the consumption of whole carp under the subsistence exposure scenario resulted in a significant risk. The subsistence consumption of large mouth bass fillets, bluegill fillets, and whole carp collected from below Fields Brook could pose a potential noncarcinogenic risk to anglers and their families; the reasonable maximum consumption of carp at this site was also of concern. The estimated risks were mostly attributable to methyl mercury and copper contamination. Methyl mercury has been shown to cause central nervous system effects in humans at the lowest adverse effect level of 0.003 mg/kg/day (IRIS data baseretrieval for methyl mercury, 1992). Information about the types of noncarcinogenic effects one might experience from chronic exposure to copper is not available at this time from the IRIS data base.

1.4.3 Carcinogenic Risks
A carcinogenic risk estimate could not be calculated for the consumption of small/large mouth bass collected from the Ashtabula Harbor and for bluegills collected from both the river and harbor; this was because no carcinogens were detected in these fish fillets (Table 1.3). The upper-bound carcinogenic risk estimates associated with the consumption of large mouth bass fillets collected below Fields Brook were below concern levels (i.e., less than 10[-6]) under all three exposure scenarios. Methylene chloride was the only carcinogen detected in the bass for which a toxicity value was available. The consumption of whole car was of concern at both the harbor and river under all three exposure scenarios. The carcinogenic risk from consuming carp was attributable to PCB contamination. There is a possibility that people who ingest, inhale, or have dermal contact with certain PCB mixtures may have a greater chance of incurring liver cancer; however, this statement is based on suggestive evidence rather than on verified data (IRIS data base retrieval for PCBs, 1992).

The human health risks attributable to carp consumption were probably overestimated because the risk estimates were based on data derived from whole carp instead of fillets. In addition, the data were also based on raw fish; (different reparation and cooking techniques may reduce concentrations of hydrophobic organic contaminants (e.g., PCBs) in fish if the fat is trimmed away prior to cooking.

1.4.4 Uncertainties
Several assumptions and estimated values were used in this baseline risk assessment that contributed to the overall level of uncertainty associated with the noncarcinogenic and carcinogenic risk estimates. As with most environmental risk assessments, the uncertainty of the risk estimates probably varied by around an order of magnitude or greater. The uncertainties were addressed in a qualitative way for the parameters and assumptions that appeared to contribute the greatest degree of uncertainty. One of the greatest sources of uncertainty was the assumption that exposure intakes and toxicity values would not change during the exposure duration. This assumed that human activities and contaminant levels would remain the same over the exposure duration, and that toxicity values would not be updated.

[1] The RfDP rovides an estimate of the daily contaminant exposure that is not likely to cause harmful effects during either a portion of a person's life or their entire lifetime (USEPA, 1989a).

[2] Slope factors are estimated through the use of mathematical extrapolation models, most commonly the linearized multistage model, for estimating the largest possible linear slope (within 95% confidence limits) at low extrapolated doses that is consistent with the data (USEPA, 1989a).


CHAPTER 2
Introduction

Sediments in the Great Lakes have become a repository for a variety of nutrients and contaminants, mostly as a result of industrial and municipal pollution. More stringent pollution control measures have generally reduced point sources of contamination during the past twenty years. However, problems remain with nonpoint sources of pollution (ranging from agricultural runoff to groundwater contamination) and with permit violations of effluent dischargers. In some areas of the Great Lakes, contaminated sediments now represent the primary source of anthropogenic chemicals to the aquatic environment. Consequently, concern has been raised about what remediation measures, if any, are needed to deal with the problem of contaminated sediments. In addition, these contaminants may pose a potential health risk to aquatic life, wildlife, and to human populations residing in the area of concern.

The 1987 amendments to the Clean Water Act, in Section 118(c)(3), authorize the U.S. Environmental Protection Agency's (EPA) Great Lakes National Program Office (GLNPO) to coordinate and conduct a 5-year study and demonstration project relating to the control and removal of contaminated sediments from recommended areas in the Great Lakes region. To achieve this task, GLNPO has initiated the Assessment and Remediation of Contaminated Sediments (ARCS) program. The overall objectives of the ARCS program (USEPA, 1991b), for selected Areas of Concern (AOCs), are to:

  1. Assess the nature and extent of contaminated sediments,
  2. Evaluate and demonstrate remedial options (e.g., removal, immobilization, and advanced treatment technologies) as well as the "no action" alternative,
  3. Provide risk assessments for humans, aquatic life, and wildlife exposed to sediment-related contaminants, and
  4. Provide guidance on the assessment of contaminated sediment problems and on the selection and implementation of necessary remedial actions in the Areas of Concern and other locations in the Great Lakes.

As one part of the ARCS program, baseline human health risk assessments for exposure to sediment-derived contaminants are being prepared for five AOCs: Ashtabula River, OH; Buffalo River, NY; Grand Calumet River/Indiana Harbor Canal, IN; Saginaw River, MI; and Sheboygan River, WI (Figure 2.1). The objectives of these risk assessments are to: 1) estimate the magnitude and frequency of human exposures to sediment-derived contaminants in the AOC, and 2) estimate the risk of adverse effects resulting from both typical and reasonable maximum exposures (i.e., the highest exposure that is reasonably expected to occur at a site) to contaminants. Risk estimates are determined for both noncarcinogenic (i.e., chronic or subchronic effects) and carcinogenic (i.e., probability of an individual developing cancer over a lifetime) effects resulting from direct and indirect exposures to sediment-related contaminants. These risk estimates are made using conservative assumptions about exposure scenarios when complete data are not available. Thus, the risk estimates are designed to be overprotective of human health.

This document presents a baseline human health risk assessment for the Ashtabula River AOC. The next chapter describes the AOC and its contamination problems. Successive chapters describe the risk assessment framework and provide details on how the exposure and risk estimates were generated. The final chapter gives a qualitative assessment of the uncertainties associated with the risk estimates.


REFERENCES [for Chapter 1 -- Executive Summary]

Ohio EPA. 1991 (August). Ashtabula River RAP. Stage 1 Draft. Ohio EPA, Division of Water Quality Planning and Assessment. USEPA, 1988a. Risk Management Recommendations for Dioxin Contamination at Midland, Michigan. Final Report. EPA Region 5, Chicago, IL. EPA-905/4-88-008.

USEPA, 1989a. Risk Assessment Guidance for Superfund: Human Health Evaluation Manual Part A. Interim Final. OSWER Directive 9285.7-01a.

USEPA, 1991b. ARCS: Assessment and Remediation of Contaminated Sediments. 1991 Work Plan. Great Lakes National Program Office, Chicago, IL.

Woodward-Clyde Consultants (WCC). 1991 (March 29). Ashtabula River Investigation. Draft Report: Ashtabula, Ohio. Prepared for: The Ashtabula River Group. 86C3609F-510.


LIST OF FIGURES

Figure

2.1 Map of ARCS priority areas of concern (USEPA, 1991b)
3.1 Boundaries of the Ashtabula River Area of Concern (Ohio EPA, 1991)
3.2 Location of water supply intakes and recreational facilities in the Ashtabula River AOC (Ohio EPA, 1991)
3.3 Location of point source dischargers in the Ashtabula River AOC (Ohio EPA, 1991)
3.4 Sediment pollution classification of the Ashtabula River AOC (Ohio EPA, 1991)
4.1 Components of baseline human health risk assessments
5.1 Fish sampling locations in the Ashtabula River AOC (WCC, 1991)
5.2 Surface water sampling locations in the Ashtabula River AOC (WCC, 1991)


LIST OF TABLES

Table

1.1 Amount of Fish Assumed to be Consumed per Person per Day from the Ashtabula River AOC

1.2 Noncarcinogenic Risks Based on the Hazard Index (HI) for each Exposure Scenario

1.3 Carcinogenic Risks for the Consumption of Fish in the Ashtabula River AOC

3.1 Summary of Ashtabula River AOC Point Source Discharger Compliance with Final NPDES Permit Limits (Ohio EPA, 1991)

3.2 Pollutants Identified in the Ashtabula River Area of Concern since 1975 (Y = Yes; N = No; X = Pollutant Detected in Medium) (Adapted from the Stage One RAP (Ohio EPA, 1991))

3.3 A Summary of Ambient Water Quality Standard Violations Measured in the Ashtabula River AOC (All Concentrations in ug/L) (Adapted from the Stage One RAP (Ohio EPA, 1991))

5.1 Potential Pathways by which People may be Exposed to Sediment-Derived Contaminants from the Ashtabula River AOC

5.2 Complete Exposure Pathways in the Ashtabula River AOC

5.3 List of Contaminants Analyzed in the Fish Used in this Risk Assessment

5.4 Contaminant Concentrations in Whole Carp and Bluegill Fillets Collected from the Ashtabula River AOC (WCC, 1991)

5.5 Contaminant Concentrations in Bluegill and Small/Large Mouth Bass Fillets Collected from the Ashtabula River AOC (WCC, 1991)

5.6 Generic Equation for Calculating Chemical Intakes (USEPA, 1989a)

5.7 Equation used to Estimate Contaminant Intakes Due to Ingestion of fish

5.8 Parameters used in Estimating Contaminant Intakes Due to Ingestion of Fish in the Ashtabula River AOC

6.1 EPA Weight-Of-Evidence Classification System for Carcinogenicity (USEPA, 1989a)

6.2 Human Health Risk Toxicity Data for Chemicals of Interest in the Ashtabula River AOC

7.1 Noncarcinogenic Risks Associated with Consuming Small/Large Mouth Bass Fillets (Taken from the Ashtabula Harbor) Under Typical, Reasonable Maximum (RME), and Subsistence Exposure Scenarios

7.2 Noncarcinogenic Risks Associated with Consuming Small/Large Mouth Bass Fillets (Taken from the Ashtabula River Downstream from Fields Brook) Under Typical, Reasonable Maximum (RUE), and Subsistence Exposure Scenarios

7.3 Noncarcenogenic Risks Associated with Consuming Bluegill Fillets (Taken from the Ashtabula Harbor) Under Typical, Reasonable Maximum (RME), and Subsistence Exposure Scenarios

7.4 Noncarcinogenic Risks Associated with Consuming Bluegill Fillets (Taken from the Ashtabula River Downstream from Fields Brook) Under Typical, Reasonable Maximum (RME), and Subsistence Exposure Scenarios

7.5 Noncarcinogenic Risks Associated with Consuming Whole Carp (Taken from the Ashtabula Harbor) Under Typical, Reasonable Maximum (RME), and Subsistence Exposure Scenarios

7.6 Noncarcinogenic Risks Associated with Consuming Whole Carp (Taken from the Ashtabula River Downstream from Fields Brook) Under Typical, Reasonable Maximum (RME), and Subsistence Exposure Scenarios

7.7 Carcinogenic Risks Associated with Consuming Small/Large Mouth Bass Fillets (Taken from the Ashtabula River Downstream from Fields Brook) Under Typical, Reasonable Maximum (RME), and Subsistence Exposure Scenarios

7.8 Carcinogenic Risks Associated with Consuming Whole Carp (Taken from the Ashtabula Harbor) Under Typical, Reasonable Maximum (RME), and Subsistence Exposure Scenarios

7.9 Carcinogenic Risks Associated with Consuming Whole Carp (Taken from the Ashtabula River Downstream from Fields Brook) Under Typical, Reasonable Maximum (RME), and Subsistence Exposure Scenarios


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