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Crane, J. L. 1993. Summary and Table of Contents to "Baseline Human Health Risk Assessment: Buffalo River, New York, Area of Concern," EPA-905-R93-008. Seattle, Wash.: EVS Consultants.
by
Judy L. Crane
EVS Consultants
Seattle, Washington 98119
Project Officer
Marc Tuchman
Great Lakes National Program Office
U.S. Environmental Protection Agency
Chicago, Illinois 60604-3590
Baseline Human Health Risk Assessment: Buffalo River, New, Area Of Concern
Foreword
Risk assessment is defined as the characterization of the probability of adverse effects from human and ecological exposures to environmental hazards. Risk assessments are often 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 the EPA's Great Lakes National Program Office (GLNPO) 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 the GLNPO, the Environmental Research Laboratory-Athens began a series of studies under the ARCS program that culminated in baseline risk assessments for each of five Great Lakes Areas of Concern (AOC)--Buffalo River, NY, Grand Calumet River, IN, Saginaw River, Ml, Ashtabula River, OH, and Sheboygan River, WI. EVS Consultants is conducting additional risk assessment work for the ARCS program through an interagency agreement with the National Oceanographic and Atmospheric Administration and GLNPO. This report describes an update of the baseline human health risk assessment for the population within the Buffalo River AOC. This risk assessment has been updated with new fish and sediment data collected for the ARCS program, and the results from this report will form the basis for a more detailed comparative risk assessment. This assessment is designed to provide conservative estimates of carcinogenic and noncarcinogenic risks to human health under baseline conditions.
TABLE OF CONTENTS
DISCLAIMERFOREWORD
LIST OF TABLES
LIST OF FIGURES
ACKNOWLEDGMENTS
1.0 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
2.0 INTRODUCTION
3.0 BUFFALO RIVER AREA OF CONCERN
3.1 ENVIRONMENTAL SETTING
3.2 LAND USES
3.3 LOCATION OF HUMAN POPULATIONS
3.4 WATER SUPPLY
3.5 CONTAMINATION OF FISH
3.5.1 Fish Species
3.5.2 Routes of Contamination
3.5.3 Fish Advisories
3.6 WILDLIFE ADVISORIES
4.0 RISK ASSESSMENT FRAMEWORK
4.1 CONCEPT OF RISK
4.2 RISK FRAMEWORK
5.0 EXPOSURE ASSESSMENT
5.1 EXPOSURE PATHWAYS
5.2 DATA USED IN THE EXPOSURE ASSESSMENT
5.2.1 Data Sources
5.2.2 Data Review
5.3 EXPOSURE ASSESSMENT
5.3.1 General Determination of Chemical Intakes
5.3.2 Intakes: Ingestion of Contaminated Fish
5.3.3 Ingestion of Surface Water While Swimming
6.0 TOXICITY ASSESSMENT
6.1 TOXICITY VALUES
6.2 LIMITATIONS
7.0 BASELINE RISK CHARACTERIZATION FOR THE BUFFALO RIVER
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 BUFFALO RIVER
7.3.1 Typical and Reasonable Maximum Exposures
7.3.1.1 Noncarcinogenic Risks
7.3.1.2 Carcinogenic Risks
7.3.2 Subsistence Exposure
7.3.3 Additive Risks
8.0 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: Estimating Concentrations of Hydrophobic Organic Contaminants In Surface Water
APPENDIX B: Human Toxicity Estimates for Contaminants Present In the Buffalo River Area of Concern
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 have been performed at five Areas of Concern (AOCs) in the Great Lakes region. The Buffalo River, located in western New York State, 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 contaminated sediments in the lower Buffalo River. 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, based on currently available data. The risk estimates were not extrapolated to potential future scenarios.
1.2 STUDY AREA
This risk assessment covers an area adjacent to the lower Buffalo River as it passes through Buffalo, NY before entering Lake Erie. This area has a history of water quality problems due primarily to point sources of contaminants (i.e., industrial and municipal discharges). The extent of contamination in the Buffalo River led to the International Joint Commission's (IJC) decision to designate this region as a Great Lakes AOC. In response, the New York State Department of Environmental Conservation (NYSDEC) has completed one phase of a remedial action plan (RAP) to identify and implement pollution abatement measures for the Buffalo River AOC (NYSDEC, 1989).
High concentrations of heavy metals, polychlorinated biphenyls (PCBs), polynuclear aromatic hydrocarbons (PAHs), and pesticides have been measured in different compartments of the Buffalo River (e.g., sediments, water column, and fish). Fish advisories have been issued against consuming carp from the Buffalo River because of excessive levels of PCBs. The transport of these contaminants into Lake Erie is also of concern. However, it was beyond the scope of this risk assessment to estimate human health risks to people using the nearshore areas of Lake Erie.
Contact and noncontact recreational activities are limited along the Buffalo River. Swimming and fishing are not allowed but there is anecdotal evidence that these activities occur, even near industrial outfalls. This assessment focused on two complete pathways by which residents of the lower Buffalo River could be exposed to sediment-derived contaminants: (1) consumption of contaminated carp and spottail/ emerald shiners, and (2) ingestion of surface water while swimming. A third complete pathway of dermal exposure to surface water was assumed to be insignificant in comparison to the risk resulting from the ingestion of contaminated surface water. This assumption was made because contaminants are more easily transported across the gut than the skin. Data for other exposure pathways were determined to be incomplete (e.g., ingestion of sediments).
A limited data set of fish contaminant concentrations was available for use in the exposure assessment. Carp from three different age classes (i.e., young, middle, and old), collected as part of the ARCS program, were used. Carp generally represent the most contaminated fish in water bodies due to their benthic feeding habits and high lipid content. Data from young-of-the-year spottail/emerald shiners were used to represent another type of fish. Young-of-the-year fish are an important food source for a variety of fish species consumed by humans. If young-of-the-year fish were the sole food source of piscivores, they could be used as an indicator of chemical contaminants that may be present in fish consumed by humans.
Since many species of fish travel between the river and Lake Erie, there is some uncertainty as to where the fish accumulated their contaminant burden. For the purpose of this risk assessment, it was assumed that fish collected from the mouth of the river accumulated most of their contaminant burden from the lower Buffalo River.
Noncarcinogenic and carcinogenic risks were estimated for typical, reasonable maximum, and subsistence (fish only) exposure scenarios. Typical (i.e., average) exposures were assumed to occur over a period of 9 years, whereas reasonable maximum (i.e., the maximum exposure that is reasonably expected to occur at a site) and subsistence (i.e., reliance on fish as a major source of protein) exposures were assumed to occur over a period of 30 years (USEPA, 1989a). These exposure durations were extrapolated over a period of 70 years for estimating carcinogenic risks. Exposure intakes were determined for each chemical and added for each exposure pathway.
For each of the fish exposure scenarios, different consumption patterns of fish were assumed to take place (Table 1.1). These consumption patterns were based, in part, on recommended values given in EPA Superfund guidance (USEPA, 1989a,b; 1991a), on published literature values, or on study assumptions. Based on an average meal of fish (i.e., 150 g or 0.33 lb), the amount of Buffalo River fish consumed for each exposure scenario (Table 1.1) can also be converted to meals per year using the following equation:
Ingestion Rate (meals/yr) = [Ingestion Rate (g/day)] x FI x (meal/150 g) x (365 days/ yr)
The number of meals of Buffalo River fish consumed over a year-long period for typical, reasonable maximum, and subsistence exposures corresponded to approximately 4.5, 33, and 225 meals, respectively.
A number of heavy metals and organic compounds were included in the exposure assessment. Toxicity values for the chemicals detected in the media of interest were obtained from the EPA's Integrated Risk Information System (IRIS) data base.
1.4 RISK ASSESSMENT
1.4.1 Determination of Risk
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 present (e.g., other contaminants are present at concentrations of concern) (USEPA, 1988a). HQ values for multiple substances and/or multiple exposure pathways were summed to yield an overall Hazard Index (HI). The HIs are interpreted in the same fashion as the HQs. Summing the HQs does not account for any synergistic or antagonistic effects that may occur among substances.
Carcinogenic risks were estimated as the incremental probability of an individual developing cancer over a lifetime as a result of exposure 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 represented 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 chemicals caused cancer. The EPA believes it is prudent public health policy to consider actions to mitigate or minimize exposures to contaminants when estimated, upper-bound 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
A summary of noncarcinogenic risks, as represented by the Hazard Indices, is given in Table 1.2. Noncarcinogenic risks were below levels of concern (i.e., HI<1) for typical and reasonable maximum exposure levels for the fish consumption and surface water ingestion pathways. An assumption was made that dermal exposure to surface water while swimming would also be insignificant. The risk levels were of concern (i.e., HI ranged from 2 to 4) for subsistence anglers and their families who consumed carp from the Buffalo River. Most of the risk was attributable to dieldrin contamination.
Because some of the chemicals detected in the fish do not presently have EPA approved RfD values (e.g., PCBs), this assessment may underestimate the noncarcinogenic risks from consuming fish from the lower Buffalo River area. The noncarcinogenic risk reported here is an estimated risk based on currently available data and toxicity information and should not be construed as an absolute risk.
1.4.3 Carcinogenic Risks
The estimated, upper-bound carcinogenic risks for all fish consumption exposure scenarios were at or above levels of concern (i.e., 10[-5] to 10[-6] range) (Table 1.3). The carcinogenic risk increased with the age class of carp, and the risk increased by about an order of magnitude for each exposure scenario from typical to reasonable maximum to subsistence exposures. Spottail/emerald shiners presented less risk to consumers by at least an order of magnitude, perhaps because of their young age and limited time for accumulating contaminants.
PCBs accounted for most of the carcinogenic risk from fish consumption. 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, 1993).
The carcinogenic risk associated with ingesting surface water while swimming ranged from 6 x 10[-8] to 4 x 10[-7] for typical and reasonable maximum exposures, respectively. Because these risk estimates were below levels of concern, it was also assumed that dermal exposure to surface water would also result in an insignificant carcinogenic risk.
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 ranges over 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 assumption requires that human activities and contaminant concentrations remain the same over the exposure duration, and that toxicity values would not be updated.
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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 affected area.
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:
- Assess the nature and extent of contaminated sediments,
- Evaluate and demonstrate remedial options (e.g., removal, immobilization, and advanced treatment technologies) as well as the "no action" alternative,
- Provide risk assessments for humans, aquatic life, and wildlife exposed to sediment-related contaminants, and
- 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 component of the ARCS program, baseline human health risk assessments have been 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 were to: (1) estimate the magnitude and frequency of human exposures to sediment-derived contaminants in the AOC, and (2) determine 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 were 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 were made using conservative assumptions about exposure scenarios when complete data were not available. Thus, the risk estimates were designed to be overprotective of human health.
This document presents an update of the baseline human health risk assessment for the Buffalo River AOC originally produced by Laniak et al. (1992). New fish and sediment data, collected for the ARCS program, were made available for this updated risk assessment. In addition, the exposure assessment was revised to reflect more recent EPA guidance that was utilized in the other four risk assessments conducted for the ARCS program (Crane, 1992a,b,c; 1993).
REFERENCES
[for Chapter 1--Executive Summary]Crane, J.L. 1992a. Baseline Human Health Risk Assessment: Ashtabula River, Ohio, Area of Concern. EPA-905-R92-007. U.S. Environmental Protection Agency, Environmental Research Laboratory, Athens, GA.
Crane, J.L. 1992b. Baseline Human Health Risk Assessment: Saginaw River, Michigan, Area of Concern. EPA-905-R92-008. U.S. Environmental Protection Agency, Environmental Research Laboratory, Athens, GA.
Crane, J.L. 1992c. Baseline Human Health Risk Assessment: Grand Calumet River/Indiana Harbor, Area of Concern. EPA-905-xxx-xxx. U.S. Environmental Protection Agency, Environmental Research Laboratory, Athens, GA. (awaiting EPA number)
Laniak, G.F., J.L. Martin, C. McConnell, J.L. Crane, W.W. Sutton and S. C. McCutcheon. 1992. Baseline Estimate of Human Health Risk Resulting from the Presence of Contaminated Buffalo River Sediments. Project Report to Center for Exposure Assessment Modeling, U.S. Environmental Protection Agency, Environmental Research Laboratory, Athens, GA.
NYSDEC, 1989. Buffalo River Remedial Action Plan. New York State Department of Environmental Conservation, Albany, NY.
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, 1989b. Exposure Factors Handbook. Office of Health and Environmental Assessment, Washington, DC. EPA/600/8-89/043.
USEPA, 1991a. Risk Assessment Guidance for Superfund. Volume I: Human Health Evaluation Manual. Supplemental Guidance: "Standard Default Exposure Factors." Interim Final (March 25, 1991). OSWER Directive 9285.6-03.
USEPA, 1991b. ARCS: Assessment and Remediation of Contaminated Sediments. 1991 Work Plan. Great Lakes National Program Office, Chicago, IL.
LIST OF TABLES
Table
1.2 Summary of Noncarcinogenic Risks Associated with Two Exposure Pathways in the Buffalo River AOC
1.3 Summary of Carcinogenic Risks Associated with Two Exposure Pathways in the Buffalo River AOC
5.1 Potential Pathways by which People may be Exposed to Contaminants from the Buffalo River
5.2 Complete Exposure Pathways in the Buffalo River AOC
5.3 Carp Data Collected from the Buffalo River AOC
5.4 Generic Equation for Calculating Chemical Intakes (USEPA, 1989a)
5.5 Equation Used to Estimate Contaminant Intakes Due to Ingestion of Fish
5.6 Parameters Used in Estimating Contaminant Intakes Due to Consumption of Fish from the Buffalo River AOC
5.7 Chemical Intake Values for Whole Carp, Young Age Class, for Three Different Exposure Scenarios
5.8 Chemical Intake Values for Whole Carp, Middle Age Class, for Three Different Exposure Scenarios
5.9 Chemical Intake Values for Whole Carp, Old Age Class, for Three Different Exposure Scenarios
5.10 Chemical Intake Values for Whole Spottail/Emerald Shiners, Young-of-the-Year, for Three Different Exposure Scenarios
5.11 Method for Computing Ingestion of Surface Water While Swimming
5.12 Parameters Used for Computing Ingestion of Surface Water While Swimming
5.13 Exposure Intakes Associated with Ingesting Contaminated Surface Water While Swimming
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 Buffalo River
7.1 Noncarcinogenic and Carcinogenic Risks Associated with Consuming Whole Carp, Young Age Class, from the Buffalo River Under Typical, Reasonable Maximum (RME), and Subsistence Exposure Scenarios
7.2 Noncarcinogenic and Carcinogenic Risks Associated with Consuming Whole Carp, Middle Age Class, from the Buffalo River Under Typical, Reasonable Maximum (RME), and Subsistence Exposure Scenarios
7.3 Noncarcinogenic and Carcinogenic Risks Associated with Consuming Whole Carp, Old Age Class, from the Buffalo River Under Typical, Reasonable Maximum (RME), and Subsistence Exposure Scenarios
7.4 Noncarcinogenic and Carcinogenic Risks Associated with Ingesting Contaminated Surface Water While Swimming in the Buffalo River
7.5 Carcinogenic Risks Associated with Consuming Whole Spottail/Emerald Shiners, Young-of-the-Year Age Class, from the Buffalo River Under Typical, Reasonable Maximum (RME), and Subsistence Exposure Scenarios
7.6 Summary of Noncarcinogenic Risks to People Residing in the Buffalo River AOC
7.7 Summary of Carcinogenic Risks to People Residing in the Buffalo River AOC
LIST OF FIGURES
Figure
2.1 Map of ARCS priority Areas of Concern (USEPA, 1991b).
3.1 Location of the Buffalo River Area of Concern (NYSDEC, 1989).
3.2 Location of major industries along the Buffalo River (NYSDEC, 1989).
4.1 Components of baseline human health risk assessments.