United States
Environmental Protection
Agency
Great Lakes
National Program Office
77 West Jackson Boulevard
Chicago, Illinois 60604
EPA 905-R93-008
December 1993
-------
BASELINE HUMAN HEALTH RISK ASSESSMENT
FOR THE BUFFALO RIVER, NEW YORK,
AREA OF CONCERN
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
U 5 Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th Floor
Chicago, IL 60604-3590
-------
DISCLAIMER
The information in this document has been funded by the U.S. Environmental Protection Agency. It has
been subjected 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
or recommendation for use by the U.S. Environmental Protection Agency.
-------
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, Wl. 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.
in
-------
TABLE OF CONTENTS
DISCLAIMER ii
FOREWORD iii
LIST OF TABLES vi
LIST OF FIGURES viii
ACKNOWLEDGMENTS ix
1.0 EXECUTIVE SUMMARY 1-1
1.1 OVERVIEW 1-1
1.2 STUDY AREA 1-1
1.3 EXPOSURE ASSESSMENT 1-2
1.4 RISK ASSESSMENT 1-3
1.4.1 Determination of Risk 1-3
1.4.2 Noncarclnogenlc Risks 1-4
1.4.3 Carcinogenic Risks 1-4
1.4.4 Uncertainties 1-6
2.0 INTRODUCTION 2-1
3.0 BUFFALO RIVER AREA OF CONCERN 3-1
3.1 ENVIRONMENTAL SETTING 3-1
3.2 LAND USES 3-4
3.3 LOCATION OF HUMAN POPULATIONS 3-4
3.4 WATER SUPPLY 3-5
3.5 CONTAMINATION OF FISH 3-5
3.5.1 Fish Species 3-5
3.5.2 Routes of Contamination 3-5
3.5.3 Fish Advisories 3-7
3.6 WILDLIFE ADVISORIES 3-8
4.0 RISK ASSESSMENT FRAMEWORK 4-1
4.1 CONCEPT OF RISK 4-1
4.2 RISK FRAMEWORK 4-2
5.0 EXPOSURE ASSESSMENT 5-1
5.1 EXPOSURE PATHWAYS 5-1
5.2 DATA USED IN THE EXPOSURE ASSESSMENT 5-3
5.2.1 Data Sources 5-3
5.2.2 Data Review 5-5
5.3 EXPOSURE ASSESSMENT 5-5
5.3.1 General Determination of Chemical Intakes 5-5
5.3.2 Intakes: Ingestion of Contaminated Fish 5-6
5.3.3 Ingestion of Surface Water While Swimming 5-13
6.0 TOXICITY ASSESSMENT 6-1
6.1 TOXICITY VALUES 6-1
6.2 LIMITATIONS 6-2
iv
-------
TABLE OF CONTENTS
Page
7.0 BASELINE RISK CHARACTERIZATION FOR THE BUFFALO RIVER 7-1
7.1 PURPOSE OF THE RISK CHARACTERIZATION STEP 7-1
7.2 QUANTIFYING RISKS 7-1
7.2.1 Determination of Noncarcinogenlc Risks 7-1
7.2.2 Determination of Carcinogenic Effects 7-2
7.3 HUMAN HEALTH RISKS IN THE BUFFALO RIVER 7-2
7.3.1 Typical and Reasonable Maximum Exposures 7-2
7.3.1.1 Noncarcinogenic Risks 7-2
7.3.1.2 Carcinogenic Risks 7-7
7.3.2 Subsistence Exposure 7-9
7.3.3 Additive Risks 7-9
8.0 CHARACTERIZATION OF QUALITATIVE UNCERTAINTIES 8-1
8.1 INTRODUCTION 8-1
8.2 QUALITATIVE LIST OF UNCERTAINTIES 8-1
8.2.1 Data Compilation and Evaluation 8-1
8.2.2 Exposure Assessment 8-2
8.2.3 Toxlclty Values 8-2
8.2.4 Risk Characterization 8-3
8.3 SUMMARY 8-3
REFERENCES 9-1
APPENDIX A: Estimating Concentrations of Hydrophobic Organic Contaminants In
Surface Water A-1
APPENDIX B: Human Toxlcity Estimates for Contaminants Present In the Buffalo River
Area of Concern B-1
-------
LIST OF TABLES
Table Page
1.1 Amount of Fish Assumed to be Consumed per Person per Day from the Buffalo River
for each Exposure Scenario 1-3
1.2 Summary of Noncarcinogenic Risks Associated with Two Exposure Pathways in the
Buffalo River AOC 1-5
1.3 Summary of Carcinogenic Risks Associated with Two Exposure Pathways in the
Buffalo River AOC 1-5
5.1 Potential Pathways by which People may be Exposed to Contaminants from the
Buffalo River 5-2
5.2 Complete Exposure Pathways in the Buffalo River AOC 5-2
5.3 Carp Data Collected from the Buffalo River AOC 5-4
5.4 Generic Equation for Calculating Chemical Intakes (USEPA, 1989a) 5-6
5.5 Equation Used to Estimate Contaminant Intakes Due to Ingestion of Fish 5-7
5.6 Parameters Used in Estimating Contaminant Intakes Due to Consumption of Fish
from the Buffalo River AOC 5-8
5.7 Chemical Intake Values for Whole Carp, Young Age Class, for Three Different
Exposure Scenarios 5-9
5.8 Chemical Intake Values for Whole Carp, Middle Age Class, for Three Different
Exposure Scenarios 5-10
5.9 Chemical Intake Values for Whole Carp, Old Age Class, for Three Different Exposure
Scenarios 5-11
5.10 Chemical Intake Values for Whole Spottail/Emerald Shiners, Young-of-the-Year, for
Three Different Exposure Scenarios 5-12
5.11 Method for Computing Ingestion of Surface Water While Swimming 5-14
5.12 Parameters Used for Computing Ingestion of Surface Water While Swimming 5-15
5.13 Exposure Intakes Associated with Ingesting Contaminated Surface Water While
Swimming 5-16
6.1 EPA Weight-of-Evidence Classification System for Carcinogenicity (USEPA, 1989a) 6-1
6.2 Human Health Risk Toxicity Data for Chemicals of Interest in the Buffalo River 6-3
VI
-------
LIST OF TABLES
Table Page
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 7-3
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 7-4
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 7-5
7.4 Noncarcinogenic and Carcinogenic Risks Associated with Ingesting Contaminated
Surface Water While Swimming in the Buffalo River 7-6
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 7-7
7.6 Summary of Noncarcinogenic Risks to People Residing in the Buffalo River AOC 7-10
7.7 Summary of Carcinogenic Risks to People Residing in the Buffalo River AOC 7-10
vii
-------
LIST OF FIGURES
Figure Page
2.1 Map of ARCS priority Areas of Concern (USEPA, 1991b). 2-2
3.1 Location of the Buffalo River Area of Concern (NYSDEC, 1989). 3-2
3.2 Location of major industries along the Buffalo River (NYSDEC, 1989). 3-3
4.1 Components of baseline human health risk assessments. 4-3
VIII
-------
ACKNOWLEDGMENTS
EVS Consultants gratefully acknowledges the U.S. EPA's Great Lakes National Program Office (GLNPO)
in Chicago, IL and the National Oceanographic and Atmospheric Administration (NOAA) in Seattle, WA
for their support during the course of this work. Alyce Fritz was the NOAA Project Officer, whereas Marc
Tuchman was the EPA Project Officer. This risk assessment was prepared by Judy Crane as part of the
EPA's Assessment and Remediation of Contaminated Sediments (ARCS) program. Previous technical
support, provided by AScI Corporation and the EPA's Center for Exposure Assessment Modeling,
Environmental Research Laboratory, Athens, GA was appreciated.
In-house review of this report was provided by Robert Dexter and Beth Power. Angela Crampton,
Stephanie Huguet, Vickie Duff, Jackie Gelling, and Elisa Eichen assisted with report production. Sandra
Salazar was the EVS Project Manager for this work.
IX
-------
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.
1-1
-------
1.3 EXPOSURE ASSESSMENT
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; 1991 a), on published literature values, or on study
assumptions. Based on an average meal of fish (i.e., 150 g or 0.33 Ib), the amount of Buffalo River fish
1-2
-------
TABLE 1.1. AMOUNT OF FISH ASSUMED TO BE CONSUMED PER PERSON PER DAY FROM THE
BUFFALO RIVER FOR EACH EXPOSURE SCENARIO
Exposure Scenario
Typical
Reasonable Maximum
Subsistence
Ingestion
Rate*
(g/day)
19.2
54
132
X Fl**
0.10
0.25
0.70
Amount of Buffalo
R. Fish Consumed
(9/day)
1.92
13.5
92.4
* Sources: Typical (West et al., 1989); Reasonable Maximum and Subsistence (USEPA,
1991 a)
** Fl = Fraction of fish (i.e., carp or spottail/emerald shiner) estimated to be ingested from the
Buffalo River (study assumption).
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 Fl 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,
The RfD provides 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).
1-3
-------
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 factor2 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 10s to 10"8 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., Hl<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., 10s to 10* 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
Slope factors are estimated through the use of mathematical extrapolation models for
estimating the largest possible linear slope (within 95% confidence limits) at low
extrapolated doses that is consistent with the data (USEPA, 1989a).
1-4
-------
TABLE 1.2. SUMMARY OF NONCARCINOGENIC RISKS ASSOCIATED WITH TWO EXPOSURE
PATHWAYS IN THE BUFFALO RIVER AOC*
Exposure
Pathway
Fish Consumption
Carp
Carp
Carp
Surface Water Ingestlon
Age Class
Young
Middle
Old
-
Exposure Scenario
Typical RME Subsistence
0.04
0.05
0.08
0.002
0.3
0.4
0.6
0.005
2
2
4
-
Non-carcinogenic risks were averaged over the same period as the exposure duration.
TABLE 1.3. SUMMARY OF CARCINOGENIC RISKS ASSOCIATED WITH TWO EXPOSURE PATHWAYS
IN THE BUFFALO RIVER AOC*
Exposure
Pathway
Fish Consumption
Carp
Carp
Carp
Spottail/Emerald Shiners
Surface Water Ingestlon
Age Class
Young
Middle
Old
Young-of-the-Year
-
Exposure Scenario
Typical RME Subsistence
5E-05
8E-05
1E-04
4E-06
6E-08
1E-03
2E-03
3E-03
9E-05
4E-07
9E-03
1E-02
2E-02
6E-04
-
Carcinogenic risks were averaged over a period of 70 years (i.e., average lifetime of an individual).
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 6x10* to
4 x 107 for typical and reasonable maximum exposures, respectively. Because these risk estimates were
1-5
-------
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.
1-6
-------
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:
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 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, Ml; and Sheboygan River, Wl (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
2-1
-------
ARCS1 PRIORITY
AREAS OF CONCERN
GREAT LAKES AREAS OF CONCERN
1. SHEBOYGAN HARBOR
2. GRAND CALUMET/ INDIANA HARBOR
3. SAGINAW RIVER/BAY
4. ASHTABULA RIVER
5. BUFFALO RIVER
Assessment and Remediation of Contaminated Sediments
0 JO 1OO 1JO 200
I.I I I I
OMATUKSB H*nO
Figure 2.1. Map of ARCS priority Areas of Concern (USEPA, 1991b).
2-2
-------
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).
2-3
-------
CHAPTER 3
BUFFALO RIVER AREA OF CONCERN
3.1 ENVIRONMENTAL SETTING
The Buffalo River, located in the City of Buffalo in western New York State, has been identified as one of
43 Great Lakes AOCs by the International Joint Commission. This ranking is given to areas where
environmental quality is degraded and designated uses of the water are impaired. The boundaries of the
Buffalo River AOC extend from the mouth of the Buffalo River to the farthest point upstream that is
impacted by lake effects (i.e., the farthest point that is typically influenced by water surface elevation
variations in Lake Erie) (Figures 3.1 and 3.2). A Stage One Remedial Action Plan (RAP) for the Buffalo
River was prepared by the New York State Department of Environmental Conservation (NYSDEC), in
cooperation with the Buffalo River Citizens' Committee (NYSDEC, 1989). Impaired uses in the AOC were
identified in the RAP. The RAP was the major source of information for this chapter, and the reader
should refer to it for a thorough description of the physical site, as well as for detailed information on the
sources and extent of multimedia contamination in the AOC.
In the past, the Buffalo River AOC was a major industrial and shipping center. Agricultural and
manufactured products were produced and shipped, along with raw materials, to other ports of call. As
a result of this development, the Buffalo River was used for transportation, as a source of fresh water for
industrial processes, and as a receptor of industrial discharges. However, with the development of the
St. Lawrence Seaway system in the 1950s, and the more recent migration of industries from the Northeast,
much of the industrial and commercial activity along the river has been displaced. Consequently, the
quality of the waterfront has been reduced due to a number of abandoned and/or decaying buildings,
junkyards and vacant lots.
The contamination problems in the Buffalo River AOC have arisen primarily from the discharge of industrial
and municipal effluents. Past and present industrial users included grain milling firms, chemical
companies, coke and steel operations, oil refineries, and a variety of smaller companies. Many of the
former industrial sites within the study area are abandoned. There are currently 7 municipal and 13
industrial wastewater dischargers within the Buffalo River watershed (NYSDEC, 1989). Other dischargers
to the system include small residential and commercial wastewater facilities in the non-urban areas and
intermittent, storm related discharges from combined sewers. In addition, 32 inactive hazardous waste
sites are believed to drain into the lower portion of the AOC and Lake Erie.
The bottom sediments of the Buffalo River are known to be contaminated with a variety of chemicals. A
navigable channel is maintained, by dredging, so that commercial shipping and recreational boating can
take place. Open water disposal of the dredged sediments is no longer allowed because of high levels
3-1
-------
Buffalo River
Area of Concern Map
Figure 3.1. Location of the Buffalo River Area of Concern (NYSDEC, 1989).
3-2
-------
Chemicals
Mobil Oil
Figure 3.2. Location of major industries along the Buffalo River (NYSDEC, 1989).
3-3
-------
of heavy metals (i.e., arsenic, barium, copper, iron, lead, manganese, zinc) and cyanide in the sediments.
The dredged sediments are being stored in a confined disposal facility which is expected to be filled by
the mid-1990s.
3.2 LAND USES
Approximately one-fifth of the total acreage along the Buffalo River AOC is presently unused. Almost one-
half of the vacant land is privately owned, about one-third is owned by the city, and the remainder is
owned by other public entities. Most of the occupied property near the river is used to support industrial,
manufacturing, and transportation activities. More than one-half of the present land area along the river
is not irrevocably committed to its present use and is susceptible to future land-use changes.
Future land use rezoning, as described in the "Buffalo Waterfront Revitalization Program,1 calls for
reclassifying 60% of the 2600 acres of industrial land along the river to other uses, such as residential and
commercial use (NYSDEC, 1989). Proposed future land uses include: (1) parks, recreation and open use,
(2) coastal zone residential and commercial use, (3) coastal zone mixed use, and (4) coastal zone
industrial use. The new residential and commercial districts would encourage water-dependent uses such
as marinas as well as water enhanced uses. Water-enhanced activities are those that may be located
inland but are enhanced by being located near the waterfronts, such as residences or restaurants that
may take advantage of the waterfront view. Revitalization plans also call for development of shallow
waters for fish habitat and fish propagation. Consequently, more recreational fishing may take place in
the AOC if proposed land uses are implemented.
3.3 LOCATION OF HUMAN POPULATIONS
Several residential areas are located along the Buffalo River AOC, including the First Ward and the Valley.
While these communities have been hurt by the decline of industries along the river, their residents would
be expected to benefit from revitalization of the river and improvement of water quality conditions. In
addition, the residents of the city of Buffalo and its non-urban areas are potential users of the AOC if
conditions improve. However, the population exposed to the river under present conditions is limited.
There is presently one marina, a naval park, and a Veterans' memorial near the mouth of the river. With
these exceptions, there are no official public access areas or recreation sites. However, it has been
determined through site inspections and discussions with local residents, that the AOC is utilized for some
swimming and fishing. Numerous combined sewer outfalls (CSOs) near the river are used as fishing and
swimming platforms. In addition, children and teenagers have been observed swimming by the breakwalls
of abandoned factories; they gain access to the river by a ladder hanging from the breakwall (K. Irvine,
State University College at Buffalo, personal communication, 1992).
3-4
-------
3.4 WATER SUPPLY
The water supply for the City of Buffalo comes from Lake Erie; the intake pipe is located directly in front
of the U.S. Coast Guard Station. The water travels through the intake pipe to the Water Filtration Plant
on LaSalle Park, adjacent to the harbor. The Buffalo River is not currently used as a public water supply,
and it is unlikely that it would be used for that purpose in the future.
3.5 CONTAMINATION OF FISH
3.5.1 Fish Species
The Buffalo River contains a variety of fish species. Carp, goldfish, carp-goldfish hybrids, bullheads,
pumpkinseed, and some white suckers appear to be year-round river residents. Emerald, spottail and
golden shiners, and gizzard shad are lake species that utilize the river for spawning in spring and early
summer. White suckers, redhorse suckers, and freshwater drum are primarily benthic lake species that
make spring spawning runs into the Buffalo River. Salmonids and walleye may use the river to spawn
upstream. Because the majority of the river banks are artificial and drop off quickly to 7 m, the amount
of shallow, protected habitat necessary for the survival of the young of most fish species is small.
(NYSDEC, 1989)
3.5.2 Routes of Contamination
One of the primary ways in which people in the Great Lakes region have been exposed to sediment-
derived contaminants is through the consumption of contaminated fish. The specific mechanisms by
which contaminants may be transferred from sediments to fish are still being elucidated. Part of the
problem with determining these mechanisms is that different fish species occupy different habitats in the
water column [e.g., benthic (bottom) versus pelagic (open water) habitats] and their diet and metabolism
may change with age. This section will examine some of the ways in which fish occupying a river/harbor
area of the Great Lakes, such as the Buffalo River, may accumulate contaminants, assuming that the
major source of pollutants comes from in-place contaminated sediments.
The group of contaminants that have been of major concern in the Great Lakes are hydrophobic organic
compounds (HOCs) such as PCBs and DDT. These compounds are persistent in the environment, due
to their physical-chemical properties, and will preferentially accumulate in the lipids of organisms relative
to other compartments (e.g., muscle, bone). Many of the commercially exploited Great Lakes fish have
relatively high amounts of body fat (e.g., lake trout, lake whitefish, and channel catfish), and thus would
be expected to contain higher levels of lipid soluble HOCs than species characterized by low body fat
(e.g., yellow perch and suckers) (Kononen, 1989).
The accumulation of contaminants in fish lipids can occur by two routes: (1) diffusion across the gills into
the body, and (2) transfer from the gut into the body after the consumption of contaminated food
3-5
-------
(Swackhamer and Hites, 1988). For the first route, the uptake of contaminants from water is functionally
dependent on fish respiration and is related to the transfer of dissolved oxygen across the gill surfaces
(Weininger, 1978). For the second route, the flux of contaminant transfer through feeding is dependent
on the following factors: (1) contaminant concentration in food, (2) rate of consumption of food, and (3)
degree to which the ingested contaminant in the food is actually assimilated into the tissues of the
organism. The assimilation of pollutants is affected by the desorption and excretion of contaminants from
body tissues, and by the growth of the organism (Thomann and Connolly, 1984).
There is some uncertainty as to whether compounds sorbed to sediment particles will be available to fish
for uptake. A chemical equilibrium model would assume that contaminant concentrations in the fish and
sediments would be in equilibrium through their individual equilibrium coefficients with the water column
(Connor, 1984). Studies with marine bottom fish in urban bays seem to indicate that the concentration
of organic contaminants in the fish is correlated with the sediment concentration of those compounds
(Connor, 1984; Malins et al., 1984). This correlation may depend on the area's physical flushing capacity
(residence time of water in a basin) and the metabolism of the organism (Connor, 1984). Similarly, a good
correlation between the types of contaminants found in sediments collected from areas of industrial and
urban development with the types of contaminants detected in freshwater carp from the same area has
been made (Jaffe et al., 1985). Carp tend to remain in a local territory and, for the most part, are benthic
feeders; thus, they would be expected to serve as a reasonable barometer of the types of contaminants
(especially organic compounds) found in their aquatic environment. In another study, Brown et al. (1985)
hypothesized that PCB concentrations in pelagic (i.e., open water) consumers of benthic-feeding
organisms in the Hudson River were largely controlled by PCB levels in the surficial sediments. While the
aforementioned studies seem to indicate some causal linkage between contaminant concentrations in
sediment and fish, there is a degree of uncertainty associated with this linkage. One of the difficulties with
assessing the impacts of sediment contaminants on fish is that the factors controlling their bioavailability
are not well understood, nor is there a basic understanding of trophic transfer from benthic to pelagic food
chains (Bierman, 1990).
Due to the difficulty involved with assessing sediment-fish linkages in the field, controlled laboratory
experiments have been conducted. Seelye et al. (1982) exposed young of the year perch to a slurry of
contaminated sediments for 10-days to simulate the conditions these fish would encounter during
dredging. Although the perch accumulated organic compounds and heavy metals from the resuspended
sediments, It is not known if the contaminants in the fish reached steady state. In another experiment by
Kuehl et at. (1987), carp exposed to Wisconsin River sediment for 55 days accumulated 7.5 pg/g of
2,3,7,8-TCDD; maintaining exposed fish in clean water for an additional 205 days resulted in the
depuration of 32-34% of 2,3,7,8-TCDD. The most likely uptake route for 2,3,7,8-TCDD in the carp was
through the ingestion of contaminated sediments while feeding (Kuehl et al., 1987). In another
experiment, lake trout that were exposed to Lake Ontario sediment and smelt in long term lab experiments
appeared to bioaccumulate 2,3,7,8-TCDD primarily through the food chain and secondarily through
contact with contaminated sediment (Batterman et al., 1989). These lake trout did not bioaccumulate a
3-6
-------
significant concentration of 2,3,7,8-TCDD from the water column, even under simulated equilibrium
conditions and with low suspended solids concentrations (Batterman et al., 1989).
Recent evidence indicates that concentrations of HOCs in fish are primarily the result of food chain
biomagnification and not equilibrium partitioning from the sediments or water column (Oliver and Niimi,
1988; Batterman et al., 1989). In Lake Ontario, samples from all trophic levels in the planktonic (water to
plankton to mysid to alewive/smelt to salmonid) and the benthic (water to sediment/suspended sediment
to amphipod/oligochaete to sculpin to salmonid) food chains showed classic biomagnification of PCBs
with successive trophic levels (Oliver and Niimi, 1988). Thus, the rate at which contaminant
concentrations increase with body size will be a function of how efficiently the contaminant is excreted
after assimilation (Borgmann and Whittle, 1991). In turn, the assimilation of contaminants in fish will be
affected by declines in feeding and clearance rates as growth occurs (Pizza and O'Connor, 1983).
Temperature has also been found to affect the accumulation of PCBs in certain adult species of fish
because temperature controlled food consumption, growth, and lipid content (Spigarelli et al., 1983).
Other contaminants, such as mercury, are also of concern in the Great Lakes. Unlike HOCs, mercury
appears to accumulate in fish tissues through direct uptake from the water column (Gill and Bruland,
1990). The major form of mercury in the water column is the highly toxic methylated mercury species.
Because of the problem of mercury contamination in fish in the Great Lakes region, fish advisories have
been issued for certain size classes of sport fish.
3.5.3 Fish Advisories
The Great Lakes jurisdictions have issued consumption advisories for sport fish since the late 1960s and
early 1970s. These consumption advisories are based on the relationship between tissue concentrations
of contaminants in individual size classes and species of fish and on specific trigger levels. When tissue
concentrations exceed some trigger level (usually U.S. Food and Drug Administration action levels),
consumption advice is issued by the states. The Governors of the Great Lakes States called for the
uniform development of fish consumption advisories by the states in the 1986 Great Lakes Toxic
Substances Control Agreement (Foran and VanderPloeg, 1989). This agreement resulted in the formal
establishment of the Great Lakes Sport Fish Consumption Advisory Task Force. The Task Force has
recently prepared a draft advisory protocol for PCBs. The advisory utilizes a weight-of-evidence derived
Health Protection Value (HPV) which is intended to encompass acceptable cancer and
reproductive/developmental risk. This value is designed to provide a consistent and scientifically
defensible endpoint for the protection of public health. The development of final advisories for each of
the Great Lakes will help reduce any confusion the fishing public and those consuming Great Lakes sport
fish may have had with previously inconsistent consumption advice for the same area.
The EPA has recently been involved with promoting consistent monitoring and risk assessment
procedures amongst the states for determining fish and shellfish advisories. The EPA Office of Water has
developed a nonregulatory, technical guidance manual for state and local agencies to use for sampling
3-7
-------
and analyzing contaminants in fish and shellfish tissue (U.S. EPA, 1993). Future guidance will be provided
on risk assessment, risk management, and risk communication issues for determining fish and shellfish
consumption advisories.
The Buffalo River is currently classified for fishing (Class D) under the New York State Stream
Classification System. This classification is the basis for restoration of impaired best uses of the river.
The New York State Health Department issued a 1987-88 fish and wildlife advisory to eat no carp from
the Buffalo River based on fish sampling data collected by the NYSDEC. The advisory was based on one
analysis of a 1984 composite sample consisting of three fish, which found elevated levels of PCBs at 6.7
ug/g and chlordane at 0.53 ug/g. The State Health Department recommends that in those waters where
specific advisories are issued, women of childbearing age, infants, and children under the age of 15
should not eat fish with elevated contaminant levels. The Food and Drug Administration's tolerances for
PCBs and chlordane in fish are 2 ug/g and 0.3 ug/g, respectively. Based on this exceedance of FDA
tolerances and the state consumption advisory, a use impairment for fish and wildlife consumption exists
for the Buffalo River.
In the Buffalo River, the tainting of fish flesh and occurrence of fish tumors may possibly be due to
contaminants present in the sediments. The substances of primary concern for tainting of fish in the
Buffalo River are phenols (especially chlorinated phenols). It has been reported that some fish taken from
the river have had a noticeable PAH odor in their stomach contents (J. Black, U.S. Fish and Wildlife
Service, personal communication, 1992). Black et al. (1985) have shown that extracts of Buffalo River
sediments induce fish tumors and that feral brown bullhead caught in the Buffalo River appear to have
a high prevalence of neoplasms (i.e., tumors). These tumors may be due to PAHs, although direct
evidence is lacking to support this observation. A high incidence of preneoplasia and neoplasia (i.e., a
tumorous condition) were also found in a study of 100 brown bullhead, collected during June, 1988, for
the ARCS program (Mueller, 1992). These findings supported a hypothesis of chemical etiology since
organic chemicals (e.g., PAHs, PCBs) found in the sediments are known to be initiators and promoters
of cancer.
3.6 WILDLIFE ADVISORIES
The types and population distributions of wildlife around the Buffalo River AOC is not well known.
Waterfowl are frequently observed on the river, and mammals, such as muskrats, have established
themselves in nearby wetland areas at Tifft Farm and Times Beach.
A general health advisory for waterfowl recommends that no mergansers or common goldeneyes should
be eaten because they are the most heavily contaminated waterfowl species in New York (New York State
Department of Health, 1989). Other waterfowl should be skinned, and the fat should be removed before
cooking. People should limit eating waterfowl to two meals per month. In general, wood ducks and
Canadian geese are less contaminated than other waterfowl species in the State of New York. Dabbler
3-8
-------
ducks and diving ducks have increasingly higher contaminant levels. There does not appear to be any
waterfowl hunting in the Buffalo River AOC.
Snapping turtles are consumed by some people in the Great Lakes region, although it is not known if
snapping turtles are prevalent in the Buffalo River AOC. A general health advisory for snapping turtles
warns women of childbearing age, and children under the age of 15, to avoid ingesting snapping turtles
or any soup or stew made with snapping turtle meat from New York (New York State Department of
Health, 1989). For people that consume snapping turtles, all fat should be trimmed away and discarded.
In addition, the liver and eggs should also be discarded prior to cooking the meat.
3-9
-------
CHAPTER 4
RISK ASSESSMENT FRAMEWORK
4.1 CONCEPT OF RISK
People are subject to a number of risks throughout their day which may cause them immediate or delayed
harm. Some risks arise from personal choices (e.g., driving a car, participating in sports) while other risks
may result from things people have little control over (e.g., breathing urban air, being a victim of a random
crime). In terms of human health risks resulting from exposure to some chemical, biochemical, or physical
agent, risks are classified into two categories: carcinogenic and noncarcinogenic risks.
Cancer is the leading cause of death for women in the United States, and most cancers, for both men
and women, are caused by factors resulting from life style choices [e.g., smoking, drinking alcohol,
consuming a diet high in animal fat, being overweight, or staying out in the sun too long (ultraviolet light
exposure)] (Henderson et al., 1991). In particular, tobacco (alone or in combination with alcohol)
accounts for one of every three cancer cases occurring in the U.S. today (Henderson et al., 1991).
Occupational exposures to specific carcinogens (especially asbestos) account for only about 4% of the
cancers in the United States (Henderson et al., 1991). Although nonoccupational exposures to
environmental contaminants probably cause an even smaller fraction of the cancers reported in the U.S.,
it is important to safeguard the publics health from unnecessary risks. In addition, environmental
contaminants may also pose a noncarcinogenic risk to human health.
Noncarcinogenic risks include chronic and subchronic effects to people. Included in this risk category
are birth defects, respiratory diseases (e.g., asthma), liver diseases, learning disabilities, etc. One way
to examine for incidences of these risks in human populations is through epidemiological studies. Three
sets of studies of the impacts of human exposure to PCB contaminated fish from the Great Lakes basin-
the Michigan Sports Fisherman Cohort, the Michigan Maternal/Infant Cohort, and the Wisconsin
Maternal/Infant Cohort were evaluated using epidemiologic criteria (Swain, 1991). The results from
comparing the studies against each other, and against comparable data from other geographic locales,
strongly suggests a causal relationship between PCB exposure and alterations in both neonatal health
status and in early infancy (Swain, 1991). However, there is no evidence that these short-term effects lead
to any chronic health effects (Bro, 1989). Possible developmental effects in infants and children will not
be addressed in this risk assessment because complex pharmacokinetic models, which are not well
developed in the risk assessment field, would have to be used. Thus, it is beyond the scope of the ARCS
program to address this issue in any great detail (USEPA, 1991b).
4-1
-------
4.2 RISK FRAMEWORK
Risks associated with environmental exposures to contaminants are difficult to assess because: (1) the
exposure itself is often difficult to document and (2) the exposure does not always produce immediately
observable effects. Due to these difficulties, human health risks associated with exposures to
contaminants must often be estimated via scenarios using standard EPA exposure parameters.
The approach used for this baseline human health risk assessment followed exposure and risk
assessment guidelines established by the EPA for use at Superfund sites (USEPA, 1988b; 1989a,b;
1991 a). Although the Buffalo River is not a Superfund site, the risk assessment procedures developed
for the Superfund Program can be applied to this site to estimate current risks to people residing in the
AOC. Unlike the Superfund risk assessments, this assessment did not consider risks resulting from future
scenarios (e.g., future risks associated with turning a contaminated site into a playground). Instead, this
risk assessment was based on the most up-to-date information available to estimate current
noncarcinogenic and carcinogenic risks to human populations in the lower Buffalo River.
The procedures used in this risk assessment are outlined briefly in Figure 4.1. The first step in the
process was to obtain information about the Buffalo River from documents such as the Remedial Action
Plan (NYSDEC, 1989) and ARCS 'Information Summary1 (Lee et al., 1991). In addition, a search for the
latest data on contaminant levels in the environmental media of interest was conducted to characterize
the extent of contamination at the site. The next step was to determine the exposure pathways by which
people could come in contact with sediment-derived contaminants from the river. The most complete and
current data sets were then evaluated to judge if adequate quality assurance/quality control (QA/QC)
protocols were followed. Next, based on the exposure pathways and sites of exposures, the most current
environmental data were used to determine contaminant intake levels. Intake levels are essentially
equivalent to administered doses and are expressed in units of mg chemical/kg body weight-day. These
chemical intake levels were then integrated with noncarcinogenic and carcinogenic toxicity data, obtained
from verified and interim EPA sources, to estimate the respective human health risks to people in the
lower Buffalo River. Finally, because of the number of assumptions that went into each step of the risk
assessment procedure, a qualitative listing of the uncertainties involved in these assumptions was made.
4-2
-------
Site Characterization
Review & Evaluation
of Existing
Chemical Data
Toxic Ity Profiles
Evaluation of
Base I Ine Risks
1
Determination of
ProbabIe Exposure
Pathways
Determination of
Exposure Point
ConcentratIons
i
Determination of
Contamlnant
Intakes/Exposure
I
Risk/Hazard
Character IzatI on
Character IzatI on
of Uncertainty
Figure 4.1. Components of baseline human health risk assessments.
4-3
-------
CHAPTER 5
EXPOSURE ASSESSMENT
5.1 EXPOSURE PATHWAYS
In this exposure assessment, the magnitude, frequency, duration, and route of direct and indirect
exposures of people to sediment-derived contaminants from the Buffalo River AOC will be determined.
The exposure assessment was updated from that of Laniak et al. (1992) in that new fish data, collected
for the ARCS program, were used. In addition, more recent EPA guidance was utilized, and standard EPA
exposure parameters were used in the absence of site-specific data.
Exposures to contaminants in the Buffalo River can potentially occur via three pathways: dermal contact,
inhalation, and ingestion. Dermal contact involves direct contact of the skin with either contaminated
sediments, riverplain soils, or overlying water. Inhalation of airborne vapors or dust may introduce
chemicals of potential concern into the respiratory system. Ingestion of contaminants through the
consumption of contaminated soils, sediment, or food (e.g., fish) is potentially significant because of the
direct transfer of contaminants across the gut.
The potential pathways by which people may be exposed to contaminants from the lower Buffalo River
are given in Table 5.1. These pathways were then examined to determine whether they were complete
or incomplete. A pathway is complete if there is: (1) a source or chemical release from a source, (2) an
exposure point where contact can occur, and (3) an exposure route by which contact can occur (USEPA,
1989a). Otherwise, the exposure pathway is incomplete if one of these conditions is not met. Six
pathways appear to be incomplete:
1. Ingestion of contaminated drinking water: the Buffalo River is not used as a
source of drinking water in the AOC.
2. Ingestion of sediments: the ingestion of bottom sediments does not appear to
be occurring.
3. Ingestion of contaminated soils: the ingestion of contaminated soils from the
river banks does not appear to be occurring. Much of the river is lined with
bulkheads, thus eliminating access to the river banks.
4. Dermal contact with contaminated soils: the river bank soils are mostly
inaccessible to people; thus, this pathway is unlikely to be complete.
5. Dermal contact with contaminated sediments: No evidence was available that people
would have direct contact with the sediments. People that swim in the river are most
likely to gain access to the river from several combined sewer outfalls and from ladders
on the bulkhead walls. It seemed unlikely that people would gain direct access to the
5-1
-------
TABLE 5.1. POTENTIAL PATHWAYS BY WHICH PEOPLE MAY BE EXPOSED TO CONTAMINANTS
FROM THE BUFFALO RIVER
INGESTION OF CONTAMINATED:
- Surface Water
- Fish and Wildlife
- Drinking Water
- Sediments
- Contaminated Soils
DERMAL CONTACT WITH CONTAMINATED:
- Surface Water
- Sediments
- Soils
INHALATION OF AIRBORNE CONTAMINANTS
sediments while swimming, especially since most of the river banks are artificial and drop
off quickly to 7 m.
6. Ingestion of certain types of wildlife: No data are currently available on
contaminant levels in waterfowl or wildlife that may be consumed in the AOC.
Although four exposure pathways were considered complete in the lower Buffalo River (Table 5.2), not
all of these exposure pathways may result in significant human health risks. In terms of inhaling airborne
contaminants, it would be difficult to separate out the contribution of contaminants from the river and that
from industrial, municipal, and background sources. In addition, the contribution of airborne contaminants
from the river may be small compared to other sources. Although this exposure pathway may be
complete, the currently available data set of atmospheric contaminant levels in the Buffalo River AOC is
inadequate to quantitatively assess the risks to human health.
TABLE 5.2. COMPLETE EXPOSURE PATHWAYS IN THE BUFFALO RIVER AOC
Ingestion of Contaminated Fish
Ingestion of Surface Water while Swimming or Playing in the Water
Dermal Contact with Water while Boating, Fishing, Swimming, Water Skiing, etc.
Inhalation of Airborne Contaminants
The only complete exposure pathways that were considered for this risk assessment were the
consumption of fish, ingestion of surface water while swimming, and dermal exposure to contaminated
surface water. Noncarcinogenic and carcinogenic risks were determined for both typical (i.e., average)
and reasonable maximum exposures (i.e., the maximum exposure that is reasonably expected to occur
5-2
-------
at a site). In addition, risks were calculated for subsistence anglers that relied on the consumption of fish
for their main source of protein. The subsistence exposure scenario was chosen because of economic
problems in the area which might contribute to an underemployed/unemployed person to consume large
amounts of locally caught fish.
5.2 DATA USED IN THE EXPOSURE ASSESSMENT
5.2.1 Data Sources
Carp and shiner data were obtained from two separate sampling efforts. Three different age classes of
carp (i.e., young, middle, and old) were collected from the Buffalo River by the Great Lakes Laboratory,
State University College at Buffalo. The fish were collected specifically for the ARCS program. Each age
class included three composite samples of five, whole fish. The samples were received on November 13,
1991 by Battelle, Pacific Northwest Division, and were analyzed for eighty individual PCB congeners and
eight chlorinated pesticides (Table 5.3). The samples were analyzed using Battelle Standard Operating
Procedures (SOP) MSL-042 and MSL-044. The results were reported as ng/g on a dry weight basis and
were converted to wet weight for use in the exposure assessment.
Another data set was used to give an estimate of risk from a fish species other than carp. Young-of-the-
year spottail shiners were collected from the Buffalo River by the NYSDEC in 1987. The objective of the
sampling program was to determine chemical contaminants in young-of-the-year spottail shiners collected
from New York State Great Lakes Basin waters during 1984 to 1987 (Skinner and Jackling, 1989). When
young-of-the-year spottail shiners were not available, young-of-the-year emerald shiners or bluntnose
minnows were collected. Two samples were analyzed for the Buffalo River in 1987. Due to the limited
number of spottail shiners in the river, one sample consisted of only one young-of-the-year spottail shiner,
whereas the other sample consisted of two young-of-the-year emerald shiners (Skinner and Jackling,
1989). The samples were analyzed for 18 organic contaminants of which PCBs, p,p'-DDE, and p,p'-DDD
were detected. The results of both samples (in wet weight) were averaged for comparison of 1985 and
1987 data in the RAP (NYSDEC, 1989).
Although young-of-the-year fish (3 to 5 months of age) are not normally consumed by humans, they are
an important food source for a variety of fish species eaten by humans (Skinner and Jackling, 1989). An
assumption was made that these young shiners could provide an underestimate of contaminant
concentrations in piscivorous fish that could be consumed by humans.
Water quality data were obtained from a retrieval of the EPA's STORET data base that was performed by
the EPA's Large Lakes Research Station in Grosse lie, Ml. The data set represented the results of a
NYSDEC monitoring study of the Buffalo River. NYSDEC personnel collected water samples from the Ohio
Street bridge (approximately 1.8 km from the harbor) from March through November over the period of
1982 to 1986. Although detectable levels of some metals were reported, a select group of organic
5-3
-------
TABLE 5.3. CARP DATA COLLECTED FROM THE BUFFALO RIVER AOC
Sponsor
Code
BRF-Y-W-1
BRF-Y-W-2
BRF-Y-W-2
BRF-Y-W-2
BRF-Y-W-3
Weighted Mean
s.d.
BRF-M-W-1
BRF-M-W-2
BRF-M-W-3
Mean
s.d.
BRF-O-W-1
BRF-O-W-2
BRF-O-W-3
Mean
s.d.
%WetWt.
68.3
65.8
65.8
65.8
66.8
67.4
65.7
64.1
63.4
60.9
59.4
Chemical Concentation (ng/g, wet weight)
a-Chbrdane
26.3
19.7
20.3
22.7
29.1
25.4
4.2
29.6
25.4
40.1
31.7
7.6
36.4
51.9
84.6
57.6
24.6
g-CHordane
15.9
13.8
14.1
15.6
16.9
15.8
1.2
15.3
13.7
22.2
17.1
4.5
18.1
27
35.6
26.9
8.8
4.4' -ODD
170
84.5
86.3
99.6
158
139
43
133
95.3
140
123
23.9
178
150
242
190
47.1
4,4'-DDE
210
102
105
116
158
159
51.2
152
101
143
132
27.3
351
171
423
315
130
4,4'-DDT
21.8
16.9
16.3
17.9
21.8
20.2
2.8
ND
ND
ND
ND
ND
ND
Dieldrin
49
41
42.2
46.7
49.2
47.2
3.4
56.4
33.3
74.2
54.6
20.5
91
80.3
76.2
82.5
7.6
Total PCBs
1890
1710
1770
1940
2200
1960
206
2760
2340
3710
2940
698
5900
3110
3400
4140
1530
Footnotes!
BRF-Y-W = Buffalo River fish (carp), young age class
BRF-M-W = Buffalo River fish (carp), middle age class
BRF-O-W = Buffalo River fish (carp), old age class
ND = Not Detected
s.d. = Standard Deviation
Weighted mean was determined as: (Y-W-1 value + average Y-W-2 value + Y-W-3 value)/3
5-4
-------
chemicals were not detected. Total metals were determined from water samples that had been preserved
at a pH of less than 2. All of the analytical analyses were performed at the New York State Health
Department Laboratories using the procedures given in the NYSDEC Surface Water Analysis Guidelines
(1982,1986 editions).
The water quality data used in this exposure assessment was the same data set used by Laniak et al.
(1992) for a preliminary baseline risk assessment of the Buffalo River AOC. This data set included
estimated concentrations of heptachlor epoxide and several polynuclear aromatic hydrocarbons (PAHs)
that were derived from equilibrium partitioning relationships and known sediment concentrations. Refer
to Appendix A for a more thorough description of this partitioning method.
5.2.2 Data Review
The carp data used in the exposure assessment underwent a QA/QC review by Lockheed Engineering
and Sciences Company (Lockheed-ESC) under a contract with the EPA Environmental Monitoring
Systems Laboratory in Las Vegas, NV. The collection and analysis of these carp had to comply with a
detailed QA/QC plan, and these data have been approved for use by the ARCS program.
The quality assurance of the spottail and emerald shiner data is given in Skinner and Jackling (1989).
In general, the mean recovery of known concentrations of chemicals spiked in fish samples ranged from
97 to 103 percent for the entire study. Good quality assurance/quality control practices appeared to have
been followed in the study. Thus, the data were assumed to be of adequate quality for use in the
exposure assessment.
The water quality data did not appear to have been reviewed by Lockheed-ESC when these data were
used by Laniak et al (1992) for a preliminary baseline risk assessment of the Buffalo River. However, the
chemical analyses followed standard procedures and appear to be of adequate quality for use in the
exposure assessment. A more detailed assessment of data quality would involve the review of original
field and laboratory data sheets, and it was outside the scope of this project to perform such a task.
5.3 EXPOSURE ASSESSMENT
5.3.1 General Determination of Chemical Intakes
Once the complete exposure pathways were identified and contaminant concentrations for fish and
surface water were obtained, the exposure assessment could be conducted. Exposures were normalized
for time and body weight to determine chemical 'intakes,' expressed in units of mg chemical/kg body
weight-day. For the ingestion of contaminated fish and water, intakes represent the amount of chemical
available for absorption in the gut. The general equation for calculating chemical intakes is given in Table
5.4. Several variables are used to determine intakes, including specific information about the exposed
population and the period over which the exposure was averaged. Noncarcinogenic effects were
5-5
-------
TABLE 5.4. GENERIC EQUATION FOR CALCULATING CHEMICAL INTAKES (USEPA, 1989a)
Intake -
BWXAT
where:
Intake
CR
EFD
BW
AT
Intake = the amount of chemical at the exchange boundary (mg/kg body weight-
day)
Chemical-Related Variables
Chemical Concentration = the average concentration contacted over the exposure
period (e.g., mg/L)
Variables that Describe the Exposed Population
Contact Rate = the amount of contaminated medium contacted per unit time or
event (e.g., L/day)
Exposure Frequency and Duration = how long and how often exposure occurs.
Often calculated using two terms, EF and ED, where
EF = exposure frequency (days/year)
ED = exposure duration (years)
Body Weight = the average body weight over the exposure period (kg)
Assessment-Determined Variables
Averaging Time = period over which exposure is averaged (days)
averaged over the same time period as the exposure duration [i.e., 9 years for typical exposures and 30
years for reasonable maximum (RME) and subsistence exposures]. Carcinogenic effects were averaged
over a lifetime (i.e., 70 years). Intake variable values were selected so that the combination of all values
resulted in an estimate of either the typical, reasonable maximum, or subsistence exposure intakes.
5.3.2 Intakes: Ingestion of Contaminated Fish
The equation used to estimate intakes of contaminants due to the ingestion of contaminated fish is
provided in Table 5.5. The parameter values used in that equation are given in Table 5.6. Parameter
values were obtained mostly from recommended EPA sources. The exposure parameters used in the
typical fishing scenario were assumed to be applicable to the general angling population of Buffalo,
5-6
-------
TABLE 5.5. EQUATION USED TO ESTIMATE CONTAMINANT INTAKES DUE TO INGESTION OF FISH
Intake
CXIHXFIXEFXED
BWXAT
where:
Intake
C
IR
Fl
EF
ED
BW
AT
Intake Rate (mg/kg-day)
Contaminant Concentration in Fish (mg/kg)
Ingestion Rate (kg/day)
Fraction of Fish Ingested from Contaminated Area (unitless)
Exposure Frequency (days/yr)
Exposure Duration (yr)
Body Weight (kg)
Averaging Time (days)
whereas the reasonable maximum exposure scenario applied to recreational anglers and their families.
The subsistence exposure scenario was chosen for a sensitive subpopulation of people who would be
relying on locally caught fish for a large proportion of their diet.
At the present time, specific information on fish consumption rates and trends in the Buffalo River AOC
is not available. Information from other Great Lakes regions may be applicable to this site. The Michigan
Sport Anglers Fish Consumption Survey, conducted by West and co-workers at the University of Michigan,
may give a better indication of ingestion rates of fish by Buffalo River anglers than the default EPA
parameter values which are applied to general populations. West et al. (1989) found that for their survey,
conducted during the January-June, 1988 time frame, the average fish consumption was 18.3
g/person/day with a standard deviation of 26.8 g/person/day. Approximately 26% of the sample
household persons who ate fish consumed between 20-40 g/person/day, whereas another 10% consumed
between 40-75 g/person/day. From the survey results, West et al. (1989) estimated a year-round average
fish consumption rate of 19.2 g/person/day. A reasonable maximum ingestion rate of 54 g/person/day
was used in this exposure assessment; this number seems appropriate because it falls within the upper
10% ingestion rate of the Michigan anglers. An assumption was made that the ingestion rate included
both 'clean* and contaminated fish. Only fish consumed from the Buffalo River were assumed to be
contaminated. Because there was not any quantitative information available on the fraction of fish
ingested from the Buffalo River (i.e., Fl), conservative estimates were made.
5-7
-------
TABLE 5.6. PARAMETERS USED IN ESTIMATING CONTAMINANT INTAKES DUE TO CONSUMPTION
OF FISH FROM THE BUFFALO RIVER AOC
Var.
IR
Fl
EF
ED
BW
AT
Units
kg/day
-
day/yr
yrs
kg
days
Value
Used
0.0192
0.054
0.132
0.1
0.25
0.7
350
9
30
70
3285
10950
25550
Comment
Typical: West et al. (1989)
Reasonable Maximum Exposure (RME): USEPA
(1991 a)
Subsistence: used the 95th percentile daily intakes
averaged over 3 days for consumers of fin fish [Pao et
al. (1982) cited in USEPA (1989a)]
Typical: study assumption
RME: study assumption
Subsistence: study assumption
USEPA (1991 a)
Typical: USEPA (1989a)
RME and Subsistence: USEPA (1989a)
50th percentile average for adult men and women
(USEPA, 1989b)
9 yrs x 365 days/yr (typical noncarcinogenic risk)
30 yrs x 365 days/yr (RME and subsistence
noncarcinogenic risk)
70 yrs x 365 days/yr (carcinogenic risk)
Based on an average meal of fish (150 g or 0.33 ih), the amount of Buffalo River fish consumed for each
exposure scenario could also be converted to meals per year using the following equation:
Ingestion Rate (meals/yr) = [Ingestion Rate (g/day)] x Fl 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.
Chemical intake values for three age classes of carp and for young-of-the-year spottail/emerald shiners
are given in Tables 5.7 - 5.10. Both noncarcinogenic and carcinogenic intake rates were calculated for
three different exposure scenarios.
5-8
-------
TABLE 5.7. CHEMICAL INTAKE VALUES FOR WHOLE CARP, YOUNG AGE CLASS, FOR THREE DIFFERENT EXPOSURE SCENARIOS
Chemical
CHLORINATED HYDROCARBONS
PCBs
ORGANOCHUORINE INSECTICIDES
a-Chkxdane
g-CHordane
Dieldrin
p,p'-DDD
p,p'-DDE
Rsh Cone.
(mg/kg)
2.0E+00
2.5E-02
1.6E-02
4.7E-02
1.4E-01
1.6E-01
2.0E-02
Noncarcinogenic Intake
(mg/kg -day)
Typical RME Subsistence
5.2E-05 3.6E-04 2.5E-03
6.7E-07 4.7E-06 3.2E-05
4.2E-07 2.9E-06 2.0E-05
1.2E-06 8.7E-06 6.0E-05
3.7E-06 2.6E-05 1.8E-04
4.2E-06 2.9E-05 2.0E-04
5.3E-07 3.7E-06 2.6E-05
Carcinooenie Intake
(mg/kg-day)
Typical RME Subsistence
6.6E-06 1.6E-04 1.1E-03
8.6E-08 2.0E-06 1.4E-05
5.3E-08 1.3E-06 8.6E-06
1.6E-07 3.7E-06 2.6E-05
4.7E-07 1.1E-05 7.5E-05
5.4E-07 1.3E-05 8.6E-05
6.8E-08 1.6E-06 1.1E-05
ND - Not Detected
5-9
-------
TABLE 5.8. CHEMICAL INTAKE VALUES FOR WHOLE CARP, MIDDLE AGE CLASS, FOR THREE DIFFERENT EXPOSURE SCENARIOS
Chemical
CHLORINATED HYDROCARBONS
PCBs
ORGANOCHLORINE INSECTICIDES
a-Chtordane
g-Chlordane
Dieldrin
p,p'-DDD
p,p'-DDE
p,p'-DDT
Rsh Cone.
(mg/kg)
2.9E+00
3.2E-02
1.7E-02
5.5E-02
1.2E-01
1.3E-01
ND
Noncarcinogenic Intake
(mg/kg -day)
Typical RME Subsistence
7.7E-05 5.4E-04 3.7E-03
8.3E-07 5.9E-06 4.0E-05
4.5E-07 3.2E-06 2.2E-05
1.4E-06 1.0E-05 6.9E-05
3.2E-06 2.3E-05 1.6E-04
3.5E-06 2.4E-05 1.7E-04
Carcinogenic Intake
(mg/kg -day)
Typical RME Subsistence
9.9E-06 2.3E-04 1.6E-03
1.1E-07 2.5E-06 1.7E-05
5.8E-08 1.4E-06 9.3E-06
1.8E-07 4.3E-06 3.0E-05
4.2E-07 9.7E-06 6.7E-05
4.5E-07 1.0E-05 7.2E-05
ND = Not Detected
5-10
-------
TABLE 5.9. CHEMICAL INTAKE VALUES FOR WHOLE CARP, OLD AGE CLASS, FOR THREE DIFFERENT EXPOSURE SCENARIOS
Chemical
CHLORINATED HYDROCARBONS
RGBs
ORQANOCHLORINE INSECTICIDES
a-Chtordane
g-CNordane
Dieldrin
p,p'-DDD
p,p'-DDE
p.p'-DDT
Fish Cone.
(mg/kg)
4.1E+00
5.8E-02
2.7E-02
8.3E-02
1.9E-01
3.2E-01
NO
Noncarcinoqenic Intake
(mg/kg -day)
Typical RME Subsistence
1.1E-04 7.7E-04 5.2E-03
1.5E-06 1.1E-05 7.3E-05
7.1E-07 5.0E-06 3.4E-05
2.2E-06 1.5E-05 1.0E-04
5.0E-06 3.5E-05 2.4E-04
8.3E-06 5.8E-05 4.0E-04
Carcinogenic Intake
(mg/kg-day)
Typical RME Subsistence
1.4E-05 3.3E-04 2.2E-03
1.9E-07 4.6E-06 3.1E-05
9.1E-08 2.1E-06 1.5E-05
2.8E-07 6.5E-06 4.5E-05
6.4E-07 1.5E-05 1.0E-04
1.1E-06 2.5E-05 1.7E-04
ND - Not Detected
5-11
-------
TABLE 5.10. CHEMICAL INTAKE VALUES FOR WHOLE SPOTTAIL/EMERALD SHINERS, YOUNG-OF-THE-YEAR, FOR THREE DIFFERENT
EXPOSURE SCENARIOS
Chemical
CHLORINATED HYDROCARBONS
PCBs
ORGANOCHLORINE INSECTICIDES
a-Chbrdane
g-CHordane
Dieldrin
p,p'-DDD
p.p'-DDE
p.p'— DDT
Fish Cone.
(mg/kg)
1.4E-01
ND
ND
ND
8.0E-03
1.1E-02
ND
Noncareinogenic Intake
(mg/kg-day)
Typical RME Subsistence
3.8E-06 2.7E-05 1.8E-04
2.1E-07 1.5E-06 1.0E-05
2.9E-07 2.0E-06 1.4E-05
Carcinogenic Intake
(mg/kg-day)
Typical RME Subsistence
4.9E-07 1.1E-05 7.8E-05
2.7E-08 6.3E-07 4.3E-06
3.7E-08 8.7E-07 6.0E-06
ND = Not Detected
5-12
-------
Since the time this risk assessment was prepared, information has been obtained on the New York State
Angler Cohort Study, conducted by the State University of New York at Buffalo. The purpose of this
epidemiologic study is to characterize exposure of humans to persistent toxic chemicals (e.g., PCBs, DDT,
DDE, mirex, lead, nexachlorobenzene, PCDFs, and mercury) associated with the consumption of Niagara
River and Lake Ontario fish and wildlife. The cohort study will characterize exposure in male anglers and
their wives or partners, female anglers, and children born to this group.
The cohort study included a survey of licensed anglers between the ages of 18 and 40 who resided in
16 Upstate New York counties in close proximity to Lake Ontario (Vena, 1992). Based on preliminary data
for Lake Erie and tributaries, including the Buffalo River, 18% of the cohort fished those waters for more
than 6 days (J. Vena, State University of New York at Buffalo, personal communication, 1993). Among
those anglers, 26% ate a meal once a week or more. Among those who fished 1-5 days, approximately
6% ate a meal at least once a week. For those anglers and their spouses/partners who consumed fish
from Lake Ontario, the average fish consumption rate was 12.8 g/person/day. Although this consumption
rate was lower than the average consumption rate of 19.2 g/person/day obtained from West's study (West
et al., 1989), some of these differences may be due to the age classes included in the two studies.
Vena's study only included the 18-40 year old age group, whereas West's study included all age groups.
West et al. (undated) found that elderly (over 65) anglers had the highest fish consumption rate of 25.2
g/person/day in Michigan. Consequently, the New York State Angler Cohort Study may underestimate
fish consumption rates for the entire angler population and their families.
The New York State Angler Cohort Study is one of nine projects being funded by the Agency for Toxic
Substances and Disease Registry (ATSDR) Great Lakes Human Health Effects Research Program. The
goal of this program is to identify human populations residing in the Great Lakes basin who may be at
greater risk of exposure to chemical contaminants present in one of the Great Lakes and to help prevent
any adverse effects (H. Hicks, ATSDR, personal communication, 1993). Susceptible populations include
pregnant females, fetuses and nursing mothers, children, Native Americans, and anglers and their families.
The results of these studies will provide useful information for future risk assessments in the Great Lakes
basin.
5.3.3 Ingestion of Surface Water While Swimming
Ingestion of surface water occurs naturally during swimming. The equation used in computing this
exposure is provided in Table 5.11, followed by the parameters for the Buffalo River (Table 5.12). Where
possible, site-specific exposure values were selected following consultation with local residents and
agencies. Where values were taken from the literature, the sources of the values are provided. The
exposure intakes are listed in Table 5.13.
The dermal exposure of people to surface water in the Buffalo River AOC was assumed to result in an
insignificant risk based on the low frequency with which these exposures would take place and also in
comparison to the estimated noncarcinogenic and carcinogenic risk associated with ingesting surface
5-13
-------
TABLE 5.11. METHOD FOR COMPUTING INGESTION OF SURFACE WATER WHILE SWIMMING
Intake
CWxCRxETxEFxED
BWxAT
where:
Intake
CW
CR
ET
EF
ED
BW
AT
Lifetime Average Intake Rate (mg/kg/day)
Chemical Concentration in Water (mg/L)
Ingestion Rate (L/hour)
Exposure Time (hours/day)
Exposure Frequency (days/year)
Exposure Duration (years)
Body Weight (kg)
Period of Exposure (days)
water while swimming in the Buffalo River (see Sections 7.3.1.1 and 7.3.1.2). Although limited dermal
exposure to water may take place in the Buffalo River, it is more difficult to determine the risks from this
pathway than from an ingestion or inhalation pathway. This is because toxicity values are not developed
specifically for dermal sorption, nor are absorption rates developed well for contaminants. Thus, the
estimation of exposure for the dermal pathway, calculated as an absorbed dose, has a greater amount
of uncertainty associated with it than exposures that are based on an actual intake of contaminant into
the body. In addition, a greater risk is likely to be encountered due to the ingestion of surface water from
the Buffalo River than dermal exposure to it because the direct intake of contaminants into the gut is
usually greater than the absorption of contaminants (with varying capacities to penetrate) across the skin
interface.
5-14
-------
TABLE 5.12. PARAMETERS USED FOR COMPUTING INGESTION OF SURFACE WATER WHILE
SWIMMING
Variable
CR
ET
EF
ED
BW
AT
Units
L/hr
hr/day
day/yr
yrs
kg
days
Exposure Scenario
Typical, RME
Typical, RME
Typical
RME
Typical
RME
Typical, RME
Typical
RME
Typical, RME
Value
Used
0.05
0.5
3
6
9
30
70
3285
10950
25550
Reference
USEPA (1989a)
Study assumption
Study Assumption
Study Assumption
USEPA (1989a)
USEPA (1989a)
50th percentile average for
adult men and women (USEPA,
1989b)
9 yrs x 365 days/yr
(noncarcinogenic risk)
30 yrs x 365 days/yr
(noncarcinogenic risk)
70 yrs x 365 days/yr
(carcinogenic risk)
5-15
-------
TABLE 5.13. EXPOSURE INTAKES ASSOCIATED WITH INGESTING CONTAMINATED SURFACE
WATER WHILE SWIMMING
Chemical
METALS
Cadmium
Chromium VI
Copper
Lead
Manganese
Mercury, methyl
Nickel
Silver
Zinc
ORGANIC COMPOUNDS
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(ghi)perylene
Chrysene
Fluoranthene
Ruorene
lndeno(1 ,2.3-cd)pyrene
Napthalene
Phenanthrene
Pyrene
Heptachlor epoxide
Mean Water
Cone.
(mg/L)
2.00E-03
2.00E-02
9.00E-03
1.60E-02
1.89E-01
1.70E-04
5.00E-03
2.00E-05
2.90E-02
8.05E-03
1.94E-03
1.06E-03
1.84E-03
1.83E-04
1.80E-03
2.49E-02
2.62E-02
1.87E-04
3.00E-02
3.00E-02
1.55E-02
1.00E-02
Noncarcinogenic Intake
(mg/kg-day)
Typical RME
5.9E-09 1.2E-08
5.9E-08 1.2E-07
2.6E-08 5.3E-08
4.7E-08 9.4E-08
5.5E-07 1.1E-06
5.0E-10 1.0E-09
1.5E-08 2.9E-08
5.9E-11 1.2E-10
8.5E-08 1.7E-07
2.4E-08 4.7E-08
5.7E-09 1.1E-08
3.1E-09 6.2E-09
5.4E-09 .1E-08
5.4E-10 .1E-09
5.3E-09 .1E-08
7.3E-08 .5E-07
7.7E-08 .5E-07
5.5E-10 .1E-09
8.8E-08 .8E-07
8.8E-08 .8E-07
4.5E-08 9.1E-08
2.9E-08 5.9E-08
Carcinogenic Intake
(mg/kg-day)
Typical RME
7.5E-10 5.0E-09
7.5E-09 5.0E-08
3.4E-09 2.3E-08
6.0E-09 4.0E-08
7.1E-08 4.8E-07
6.4E-11 4.3E-10
1.9E-09 1.3E-08
7.5E-12 5.0E-11
1. IE-OS 7.3E-08
3.0E-09 2.0E-08
7.3E-10 4.9E-09
4.0E-10 2.7E-09
6.9E-10 4.6E-09
6.9E-11 4.6E-10
6.8E-10 4.5E-09
9.4E-09 6.3E-08
9.9E-09 6.6E-08
O.OE+00 4.7E-10
7.1 E- 11 7.5E-08
1. IE-OS 7.5E-08
1. IE-OS 3.9E-08
5.8E-09 2.5E-08
5-16
-------
CHAPTER 6
TOXICITY ASSESSMENT
6.1 TOXICITY VALUES
Two types of toxicity values were used in combination with exposure estimates (i.e., chemical intake
values) to calculate noncarcinogenic and carcinogenic health risks. One toxicity value, the reference dose
(RfD), provides an estimate of the daily contaminant exposure that is not likely to cause harmful effects
during either a portion of a persons' life or his/her entire lifetime. The RfD is the toxicity value used in
evaluating noncarcinogenic effects. The other toxicity value, the slope factor, is used in risk assessments
to estimate an upper-bound lifetime probability of an individual developing cancer as a result of exposure
to a particular level of a potential carcinogen. In addition, the EPA weight-of-evidence classification
scheme indicates the strength of evidence that the contaminant is a human carcinogen (Table 6.1). Slope
factors are typically calculated for potential carcinogens in Classes A, B1, and B2 as well as for Class C
on a case-by-case basis. A more detailed description of these toxicity values, summarized from 'Risk
Assessment Guidance for Superfund. Volume 1. Human Health Evaluation Manual (Part A)' (USEPA,
1989a), is given in Appendix B.
TABLE 6.1. EPA WEIGHT-OF-EVIDENCE CLASSIFICATION SYSTEM FOR CARCINOGENICITY
(USEPA, 1989a)
Group Description
A Human carcinogen
B1 or Probable human carcinogen
B2
B1 indicates that limited human data are available
B2 indicates sufficient evidence in animals and inadequate or no
evidence in humans
C Possible human carcinogen
D Not classifiable as to human carcinogenicity
E Evidence of noncarcinogenicity for humans
Chronic oral RfD values and oral slope factors were used for the food ingestion pathways examined in
this risk assessment. Toxicity values, which had undergone an EPA review process, were obtained from
the EPA's Integrated Risk Information System (IRIS) data base. For chemicals lacking a Verified value,"
interim toxicity values were obtained from the Health Effects Assessment Summary Tables (HEAST), if
6-1
-------
available. Table 6.2 lists the toxicity data used for the chemicals of interest. Although RfD values are
provided for known carcinogens, it does not imply that these levels are protective against carcinogenicity.
This table also includes the form in which the chemical was administered to the test animal or patient
(e.g., drinking water, diet, or gavage) for determination of the oral RfD. The endpoints of concern for
evaluating noncarcinogenic risks are listed in Table B-1 of Appendix B.
6.2 LIMITATIONS
This risk assessment was limited by the current availability of toxicity information. In some cases, toxicity
values were not available for some of the chemicals detected in the Buffalo River (e.g., RfD values for lead
and PCBs). In other cases, toxicity values were only available for a specific metal species rather than for
the total metal. In particular, methyl mercury was assumed to be the major form of mercury present in
this system, and chromium VI was assumed to be the major valence state of chromium in the system.
For a-chlordane and y-chlordane, both chemicals were assumed to have the same toxicity factors as total
chlordane. The uncertainties involved in these assumptions will be listed in a subsequent chapter.
6-2
-------
TABLE 6.2. HUMAN HEALTH RISK TOXICITY DATA FOR CHEMICALS OF INTEREST IN THE
BUFFALO RIVER
Chemical
METALS
Cadmium
Chromium VI
Copper
Lead
Manganese
Mercury, methyl
Nickel
Silver
Zinc
PAHs
Anthracene
Benzo(a) anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(ghi)perylene
Chrysene
Fluoranthene
Fluorene
lndeno(1 ,2,3 - cd)pyrene
Napthalene
Phenanthrene
Pyrene
CHLORINATED HYDROCARBONS
PCBs
ORGANOCHLORINE INSECTICIDES
a-Chlordane
g-Chkxdane
Dieldrin
p.p'-DDD
p,p'-DDE
p,p'-DDT
Heptachkx epoxide
OralRfD
(mg/kg/day)
5.00E-04
5.00E-03
1.30E-03
5.00E-03
3.00E-04
2.00E-02
5.00E-03
3.00E-01
3.00E-01
4.00E-02
4.00E-02
4.00E-03
3.00E-02
6.00E-05
6.00E-05
5.00E-05
5.00E-04
1.30E-05
Form
water
water
water
poisonings
diet
diet
gavage
gavage
gavage
gavage
diet
diet
diet
diet
diet
Carcinogenic
Weight of
Evidence
Source Class
a 81
a A
b D
B2
D
D
D
a D
B2
82
82
D
B2
a D
a D
82
b D
D
a D
B2
a B2
a 82
a B2
B2
B2
a B2
a B2
Source
a
a
a
a
a
a
a
a
a
b
a
a
a
a
Oral
Slope
Factor
1 /(mg/kg/day)
1.15E+01
7.30E+00
1.15E+01
1.I5E+01
7.70E+00
1.30E+00
1.30E+00
1.60E+01
2.40E-OI
3.40E-01
3.40E-01
9.10E+00
Source
d
a
d
d
a
Sources:
a: IRIS (current as of 7/20/93)
b: USEPA (1989c)
c: Interim guidance, relative to benzo(a)pyrene, suggested by OERR (USEPA, 1989d)
Blank spaces denote a lack of information for the chemical of Interest
6-3
-------
CHAPTER 7
BASELINE RISK CHARACTERIZATION FOR THE BUFFALO RIVER
7.1 PURPOSE OF THE RISK CHARACTERIZATION STEP
The purpose of the risk characterization step is to combine the exposure and toxicity estimates into an
integrated expression of human health risk. This section presents the calculated potential human health
risks associated with the consumption of contaminated fish and surface water from the Buffalo River AOC
under baseline conditions. It is important to recognize that these calculated risk estimates are not
intended to be used as actual values. Risk assessment is a regulatory process that provides risk
managers with quantitative estimates that are to be used for comparative purposes only. These risk
estimates must be interpreted in the context of all the uncertainties associated with each step in the
process. Some of the major uncertainties in this risk assessment are addressed in the following chapter.
Two means of expressing the carcinogenic and noncarcinogenic risks of adverse health effects are
presented in this chapter. First, chemical specific risks were estimated for each exposure pathway.
Secondly, chemical specific risks were added to estimate a cumulative pathway specific risk.
7.2 QUANTIFYING RISKS
7.2.1 Determination of Noncarcinogenic Risks
Noncarcinogenic effects are evaluated by comparing an exposure level over a specified time period with
a RfD derived from a similar exposure period [otherwise known as the hazard quotient (HQ)]. Thus,
HQ = exposure level (or intake)/RfD.
Hazard quotients are expressed to one significant figure in a nonprobabilistic way. In this risk
assessment, HQ values were expressed to two significant figures for each chemical; this was done to
reduce round-up error when HQ values were summed for each pathway. An HQ value of less than 1
indicates that exposures are not likely to be associated with adverse noncarcinogenic effects (e.g.,
reproductive toxicity, teratogenicity, or liver toxicity). As the HQ approaches or exceeds 10, the likelihood
of adverse effects is increased to the point where action to reduce human exposure should be
considered. Owing to the uncertainties involved with these estimates, 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). However, the level of concern does not increase linearly as
the RfD is approached or exceeded because RfDs do not have equal accuracy or precision; nor are RfDs
based on the same severity of toxic effects (USEPA, 1989a).
7-1
-------
In assessing health risks, all HQ values are representative of long term chronic exposures (i.e., exposures
assumed to occur over a period of 9 or 30 years). The sum of more than one HQ value for multiple
substances and/or multiple exposure pathways is the Hazard Index (HI). Adding the HQs does not
account for any synergistic or antagonistic effects that may occur among chemicals. For this risk
assessment, no attempt was made to distinguish between risk endpoints (e.g., target organs and related
effects) when calculating the HI. Thus, this expression of total risk may be extremely conservative; it
would be better to refine the HI to specific endpoints for HQ values greater than one. Additional
limitations of HQ values and the segregation of hazard indexes have been described elsewhere (USEPA,
1989a).
7.2.2 Determination of Carcinogenic Effects
Unlike noncarcinogenic effects, carcinogenic substances are thought to pose some degree of risk at all
exposure levels. These effects are estimated as the incremental probability of an individual developing
cancer over a lifetime as a result of exposure to the potential carcinogen. This risk is computed using
average lifetime exposure values that are multiplied by the oral slope factor for a particular chemical.
Slope factors are used to convert estimated daily intakes averaged over a lifetime of exposure directly to
the incremental risk of an individual developing cancer. The resulting carcinogenic risk estimate is
generally an upper-bound estimate, because slope factors are usually based on upper 95th percentile
confidence limits. 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 10s to 10*
range, and when noncarcinogenic health risks are estimated to be significant (USEPA, 1988a).
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 produced the same effect (i.e.,
cancer). The limitations to this approach are discussed in detail elsewhere (USEPA, 1989a).
7.3 HUMAN HEALTH RISKS IN THE BUFFALO RIVER
7.3.1 Typical and Reasonable Maximum Exposures
7.3.1.1 Noncarcinogenic Risks
Fish Consumption. Based on typical and reasonable maximum exposure levels over a 9- and a 30-year
period, respectively, estimated noncarcinogenic risks from all substances used in the assessment were
below levels of concern (i.e., Hazard Index <1) for all three age classes of carp (Tables 7.1 - 7.3).
Noncarcinogenic risks could not be estimated for spottail/emerald shiners due to the lack of reference
dose values for the chemicals (e.g., PCBs) measured in those fish. However, this does not mean that the
shiners and carp presented no risk to fish consumers. The noncarcinogenic risk reported here is an
estimated risk based on currently available data and toxicity information and should not be construed as
7-2
-------
TABLE 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
Chemical
CHLORINATED HYDROCARBONS
PCBs
ORGANOCHLORINE INSECTICIDES
a-Chkxdane
g-Chlordane
Dieldrin
p,p'-DDD
p.p'-DDE
p,p'-DDT
Fish Cone.
(mg/kg)
2.0E+00
2.5E-02
1.6E-02
4.7E-02
1.4E-01
1.6E-01
2.0E-02
Hazard Index
(Intake/RfD)
Typical RME Subsistence
0.0111 0.0783 0.536
0.0069 0.0487 0.333
0.0248 0.1746 1.195
0.001 1 0.0075 0.051
Lifetime Cancer Risk
(Intake'Oral Slope Factor)
Typical RME Subsistence
5.1E-05 1.2E-03 8.2E-03
1.1E-07 2.6E-06 1.8E-05
6.9E-08 1.6E-06 1.1E-05
2.6E-06 6.0E-05 4.1E-04
1.1E-07 2.6E-06 1.8E-05
1.8E-07 4.3E-06 2.9E-05
2.3E-08 5.4E-07 3.7E-06
CUMULATIVE RISK 0.04 0.31 2.1 5.4E-05 1.3E-03 8.7E-03
ND = Not Detected
7-3
-------
TABLE 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
Chemical
CHLORINATED HYDROCARBONS
PCBs
ORGANOCHLORINE INSECTICIDES
a-Chkxdane
g-CHordane
Dieldrin
p.p'-DDD
p,p'-DDE
p.p'-DDT
Fish Cone.
(mg/kg)
2.9E+00
3.2E-02
1.7E-02
5.5E-02
1.2E-01
1.3E-01
ND
Hazard Index
(Intake/RfD)
Typical RME Subsistence
0.0139 0.0977 0.669
0.0075 0.0527 0.361
0.0287 0.2019 1.382
Lifetime Cancer Risk
(lntake*Oral Slope Factor)
Typical RME Subsistence
7.7E-05 1.8E-03 1.2E-02
1.4E-07 3.3E-06 2.2E-05
7.5E-08 1.8E-06 1.2E-05
3.0E-06 6.9E-05 4.7E-04
1.0E-07 2.3E-06 1.6E-05
1.5E-07 3.6E-06 2.4E-05
CUMULATIVE RISK 0.05 0.35 2.4 8.0E-05 1.9E-03 1.3E-02
ND = Not Detected
7-4
-------
TABLE 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
Chemical
CHLORINATED HYDROCARBONS
RGBs
ORGANOCHLORINE INSECTICIDES
a-Chlordane
g-CNordane
Dieldrin
p,p'-DDD
p.p'-DDE
p,p'-DDT
Rsh Cone.
(mg/kg)
4.1E+00
5.8E-02
2.7E-02
8.3E-02
1.9E-01
3.2E-01
ND
Hazard Index
(Irrtake/RfD)
Typical RME Subsistence
0.0252 0.1775 1.215
0.0118 0.0829 0.567
0.0434 0.3051 2.088
Lifetime Cancer Risk
(Intake'Oral Slope Factor)
Typical RME Subsistence
1.1E-04 2.5E-03 1.7E-02
2.5E-07 5.9E-06 4.1E-05
1.2E-07 2.8E-06 1.9E-05
4.5E-06 1.0E-04 7.2E-04
1.5E-07 3.6E-06 2.5E-05
3.6E-07 8.5E-06 5.8E-05
CUMULATIVE RISK 0.080 0.57 3.9 1.1E-04 2.7E-03 1.8E-02
ND = Not Detected
7-5
-------
an absolute risk. As reference dose values become available for PCBs and other contaminants of interest,
the noncarcinogenic risk estimates should be reexamined to verify that the consumption of these types
of fish still presents a negligible noncarcinogenic risk.
Surface Water Ingestion. The noncarcinogenic risks resulting from the ingestion of surface water while
swimming under typical and reasonable maximum exposure scenarios were also estimated to be below
levels of concern (Table 7.4). Based on these observations, an assumption was made that insignificant
risks would also result from dermal exposure to surface water while swimming. This assumption was
made because the direct intake of contaminants into the gut generally results in a greater intake of
contaminants than the absorption of contaminants (with varying capacity for penetration) through the skin.
TABLE 7.4. NONCARCINOGENIC AND CARCINOGENIC RISKS ASSOCIATED WITH INGESTING
CONTAMINATED SURFACE WATER WHILE SWIMMING IN THE BUFFALO RIVER
Chemical
METALS
Cadmium
Chromium VI
Copper
Lead
Manganese
Mercury, methyl
Nickel
Silver
Zinc
ORGANIC COMPOUNDS
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(ghi)perylene
Chrysene
Fluoranthene
Fluorene
lndeno(1 .2.3-cd)pyrene
Napthalene
Phenanthrene
Pyrene
Heptachlor epoxide
CUMULATIVE SUM
Mean Water
Cone.
(mg/L)
2.00E-03
2.00E-02
9.00E-03
1.60E-02
1.89E-01
1.70E-04
5.00E-03
2.00E-05
2.90E-02
8.05E-03
.94E-03
.06E-03
.84E-03
.83E-04
.80E-03
2.49E-02
2.62E-02
1.87E-04
3.00E-02
3.00E-02
1.55E-02
1.00E-02
Hazard Index
(Intake/RfD)
Typical RME
1.2E-05 2.3E-05
1.2E-05 2.3E-05
2.0E-05 4.1E-05
1.1E-04 2.2E-04
17E-06 3.3E-06
7.3E-07 1.5E-06
1.2E-08 2.3E-08
2.8E-07 5.7E-07
7.9E-08 1.6E-07
1.8E-06 3.7E-06
1.9E-06 3.9E-06
2.2E-05 4.4E-05
1.5E-06 3.0E-06
2.3E-03 4.5E-03
0.0024 0.0049
Lifetime Cancer Risk
(Intake'Slope Factor)
Typical RME
8.4E-09 5.6E-08
2.9E-09 1.9E-08
8.0E-09 5.3E-08
7.8E-09 5.2E-08
3.4E-08 2.3E-07
6.1E-08 4.1E-07
Blank spaces denote chemicals lacking toxicity data
7-6
-------
TABLE 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
Chemical
CHLORINATED HYDROCARBONS
PCBs
ORGANOCHLORINE INSECTICIDES
a-Chbrdane
g-Chlordane
Dieldrin
p,p'-DDD
p.p'-DDE
p.p'-DDT
Rsh Cone.
(fng/kg)
1.4E-01
ND
ND
ND
8.0E-03
1.1E-02
ND
Lifetime Cancer Risk
(lntake*Oral Slope Factor)
Typical RME Subsistence
3.7E-06 8.8E-05 6.0E-04
6.5E-09 1.5E-07 1.0E-06
1.3E-08 3.0E-07 2.0E-06
CUMULATIVE RISK 3.8E-06 8.8E-05 6.0E-04
ND = Not Detected
7.3.1.2 Carcinogenic Risks
Fish Consumption. Anglers and their families were at risk of developing cancer over their lifetime as a
result of consuming either carp or shiners from the Buffalo River. The probability of developing cancer
exceeded one person in a million (1x10*) for all exposure scenarios. The estimated carcinogenic risks
resulting from the consumption of young, middle-aged, and old carp were 5 x 105. 8 x 105, and 1 x KT4,
respectively, for the typical scenario (Tables 7.1-7.3). The carcinogenic risks increased by over an order
of magnitude for recreational anglers under the reasonable maximum exposure scenario. The risk of
cancer increased with the age class of carp. Older carp would be expected to contain a greater
contaminant load of hydrophobic organic contaminants than younger carp due to their benthic-dwelling
habits and higher fat content.
For people that consumed shiners under typical and reasonable maximum exposures, the corresponding
carcinogenic risks were 4 x 10* and 9 x 10"6, respectively. The shiners posed less risk to consume than
carp, perhaps because of their young age and limited time for accumulating contaminants. In addition,
spottail/emerald shiners are lake species that utilize the river for spawning in spring and early summer,
whereas carp are year-round residents (NYSDEC, 1989). Thus, the shiners would be more likely to have
a reduced contaminant load than carp due to their lower river residence time.
7-7
-------
For each of the fish consumption scenarios presented here, PCBs accounted for the greatest proportion
of carcinogenic risk. 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. Studies with three strains of rats and two
strains of mice have verified the carcinogenicity of PCBs through the occurrence of hepatocellular
carcinomas (IRIS data base retrieval for PCBs, 1993). This evidence was used to classify PCBs as a
probable human carcinogen.
As discussed in Chapter 3, fish will preferentially accumulate PCBs and other hydrophobic organic
contaminants in their lipids. Since carp are mostly benthic feeders that generally reside in a local area,
they can be used as an indicator of local contamination problems. In addition, carp have a high lipid
content which may readily accumulate contaminants through the ingestion and assimilation of
contaminated food and possibly through the consumption of sediment while feeding. It is not possible
to estimate how much of the carcinogenic risk is directly attributable to contaminants in the sediments.
A conservative assumption could be made that nearly all of the human health risk was attributable to the
direct and indirect (e.g., food chain transfer) exposure of fish to contaminants in the sediments.
These carcinogenic risk estimates may be overly conservative because they are based on the
consumption of whole fish, rather than fillets. These risk estimates should be updated as new data
becomes available, especially for data on contaminant levels in fish fillets. Although carp are generally
regarded as an undesirable trash' fish by many anglers, they are consumed by some anglers and their
families. In addition, food scientists are examining ways in which carp flesh can be deboned and
restructured to form fabricated seafood products to make them more marketable (Stachiw et al., 1988).
These noncarcinogenic and carcinogenic risk levels were based on raw fish. At the present time,
contaminant concentrations in raw fish cannot be extrapolated to concentrations in cooked products. For
the past 20 years, Mary Zabik and coworkers from Michigan State University have been investigating
whether cooking methods can reduce pesticide and PCB residues in meat and fish (Smith et al., 1973;
Stachiw et al., 1988; Zabik, 1974, 1990; Zabik et al., 1979, 1982). However, their results have not been
consistent between and within species of fish. In one instance, different cooking methods did not result
in significant changes in the level of PCBs, DDE, or DDT in cooked carp fillets (Zabik et al., 1982). In
another case, cooking resulted in reductions of TCDD in restructured, deboned carp fillets (Stachiw et al.,
1988).
To further assess how cooking techniques may alter the level of contaminants in fish, the Michigan
Department of Public Health and Michigan State University are conducting a joint, 2-year investigation [H.
Humphrey, Michigan Department of Public Health, personal communication, 1991]. This study will be
performed on a variety of sport fish in the Great Lakes (e.g., Chinook and coho salmon) for skin-on and
skin-off fillets. The results of the Michigan study will be useful for future human health risk assessments
for determining better estimates of contaminant levels in cooked fish. For the present time, anglers can
use the following cooking techniques to reduce their risk to contaminants: (1) trim fatty areas, (2) puncture
7-8
-------
or remove skin before cooking so that fats drain away, or (3) deep-fry trimmed fillets in vegetable oil and
discard the oil.
Surface Water Ingestion. The carcinogenic risks associated with ingesting water while swimming under
typical and reasonable maximum scenarios were 6 x 108 and 4 x 107, respectively (Table 7.4). Thus,
these risk levels were not of concern. Similarly, the assumption was made that the carcinogenic risk
associated with dermal exposure to the water while swimming would also be insignificant. This
assumption has been supported by dermal exposure estimates at more contaminated sites in the Great
Lakes region [e.g., Grand Calumet River, IN (Crane, 1992c)] which have shown negligible carcinogenic
risk.
7.3.2 Subsistence Exposure
Subsistence anglers increased their risks to contaminants by nearly an order of magnitude compared to
recreational anglers in the reasonable maximum exposure scenario (Tables 7.1 - 7.3, 7.5). Although
noncarcinogenic risks increased with each successive age-class of carp, similar hazard index values were
observed for young and middle-aged carp (HI = 2). Anglers who exclusively consumed old-age class
carp, increased their hazard index value to 4. The noncarcinogenic risk was due mostly to dieldrin for
the young and middle-aged carp, and to dieldrin and a-chlordane for the old age class carp. Dieldrin has
been shown to cause liver lesions in dogs; an uncertainty factor of 100 has been applied for extrapolating
these data to humans. Chlordane has been shown to cause regional liver hypertrophy (i.e., exaggerated
growth) in female rats; an uncertainty factor of 1000 has been applied to extrapolate these data to
humans.
The risk of developing cancer ranged from 9 x 103 to 1 x 102 to 2 x 102 for anglers that consumed young,
middle-aged, and old carp as a major portion of their diet (Tables 7.1-7.3). These estimates represent
a "worst-case" scenario as it is unlikely that someone would consume this much carp over a 30 year
exposure period. Subsistence anglers that consumed shiners increased their risk of cancer to 6 x 104
(Table 7.5).
The carcinogenic risk was attributable primarily to PCB contamination in the carp and spottail shiners.
In addition, the risk associated with all of the organochlorine insecticides exceeded 105 for each age class
of carp. These carcinogenic risk levels represent an upper bound risk and may overestimate the actual
risk since the risk estimates are based on raw, whole fish.
7.3.3 Additive Risks
Risks may be added among exposure pathways (i.e., consumption of fish and surface water) to yield an
overall estimate of risk to the human population. For the Buffalo River AOC, the risk associated with
consuming fish far outweighed that of surface water ingestion. Therefore, the additive risks correspond
7-9
-------
to the fish consumption risks. Summary tables of the noncarcinogenic and carcinogenic risk estimates
are given in Tables 7.6 and 7.7, respectively.
TABLE 7.6. SUMMARY OF NONCARCINOGENIC RISKS TO PEOPLE RESIDING IN THE BUFFALO
RIVER AOC
Exposure Pathway
Fish Consumption
Carp
Carp
Carp
Spottail/Emerald Shiners
Surface Water Ingestion
Age Class
Young
Middle
Old
Young-of-
the-Year
-
Exposure Scenario
Typical RME Subsistence
0.04
0.05
0.08
_
0.002
0.3
0.4
0.6
_
0.005
2
2
4
_
-
TABLE 7.7. SUMMARY OF CARCINOGENIC RISKS TO PEOPLE RESIDING IN THE BUFFALO RIVER
AOC
Exposure Pathway
Fish Consumption
Carp
Carp
Carp
Spottail/Emerald Shiners
Surface Water Ingestion
Age Class
Young
Middle
Old
Young-of-the-Year
-
Exposure Scenario
Typical RME Subsistence
5E-05
8E-05
1E-04
4E-06
6E-08
1E-03
2E-03
3E-03
9E-05
4E-07
9E-03
1E-02
2E-02
6E-04
-
7-10
-------
CHAPTER 8
CHARACTERIZATION OF QUALITATIVE UNCERTAINTIES
8.1 INTRODUCTION
A number of assumptions and estimated values were used in the baseline risk assessments that
contributed to the level of uncertainty about the risk estimates. For most environmental risk assessments,
the uncertainty of the risk estimates ranges over an order of magnitude or greater (USEPA, 1989a). In
this chapter, a qualitative listing of the uncertainties associated with each step in the risk assessment
process will be made in order to determine the impact of these uncertainties on the final risk assessment
results.
8.2 QUALITATIVE LIST OF UNCERTAINTIES
8.2.1 Data Compilation and Evaluation
The data compilation and evaluation step is one part of the risk assessment process where uncertainties
arise. Assumptions are stated below, and their uncertainties are discussed.
• The available data for contaminant concentrations In fish, sediment, and water
samples collected from the Buffalo River were representative of the true distribution
of contaminants In the Buffalo River AOC. A moderate level of uncertainty is probably
associated with this assumption. Additional sampling over a longer period of time would
be needed to look for any temporal or spatial variability in contaminant concentrations,
and to obtain a more representative profile of contaminant concentrations in the media
of interest.
• The fish and water column data are inclusive of all contaminants present In the AOC.
In comparison to other similar locations, it is expected that additional substances are
present that were not measured to date. The contribution of unknown chemicals would
mean that the risk assessment underestimated the risk if these chemicals were present
at potentially toxic concentrations.
The fish data are representative of fish species actually caught and consumed. Other
fish species may be preferred by anglers. The data used herein for carp may
overestimate contaminant intake rates if less fatty fish are caught, whereas data for
shiners may underestimate contaminant intakes if larger, fattier fish are caught.
A complete QA/QC review of the surface water data obtained for this risk assessment
was not made because of a lack of Information supplied with the reports. Therefore,
no information about the accuracy of the data could be obtained. The uncertainty
associated with using these data is unknown, but may have been minimized by using
more up-to-date monitoring studies that generally have more rigorous QA/QC plans than
older studies.
8-1
-------
• Contaminant concentrations In consumable fish tissues may be lower than In fresh
fish depending on how the fish Is prepared and cooked. Contaminant levels may be
reduced 10-70% depending on how the fish is prepared and cooked (H. Humphrey,
Michigan Department of Public Health, personal communication, 1991). Because of this
wide range, the uncertainty associated with the resulting overestimation of risk is not well
established.
8.2.2 Exposure Assessment
A number of assumptions were made in the exposure assessment step of this baseline human health risk
assessment.
• An adequate assessment of complete and Incomplete exposure pathways was made.
There is a low uncertainty that some exposure pathways were either not identified or else
were incorrectly classified as a complete or incomplete exposure pathway.
• The exclusion of some complete exposure pathways (e.g., dermal exposure to
surface water) from the exposure assessment was justifiable because of the low
probability that these pathways would result in significant human health risks.
• The complete exposure pathways chosen for the exposure assessment represent the
primary pathways by which people In the Buffalo River were exposed to
contaminants. The pathways chosen were based primarily on observed activities and
on available data.
• The assumptions made about exposure frequency and duration variables, body
weight, life expectancy, and population characteristics were appropriate. Many of
these assumptions (e.g., body weight, life expectancy, exposure frequency) were based
on EPA guidance (USEPA, 1989a,b; 1991 a) and probably have a low to moderate level
of uncertainty associated with them. A similar level of uncertainty may be attributed to
professional judgements about the fraction of fish ingested from contaminated sources
and the number of times someone would go swimming in the Buffalo River.
8.2.3 Toxicity Values
The toxicity values (i.e., oral RfDs and oral slope factors) used in this risk assessment were either verified
values obtained from IRIS or interim values obtained from other sources. RfDs and slope factors are
subject to change as result of new information and updates of the IRIS data base. In addition, chemicals
will be added to IRIS in the future to expand the data base. Thus, this risk assessment is 'dated* to the
toxicity values available at the time it was prepared. Listed below are the uncertainties associated with
using these toxicity values.
• RfD values and slope factors have a certain amount of uncertainty associated with
them. Uncertainty and modifying factors are incorporated into the calculation of RfDs
(see Appendix A) and take into consideration factors such as extrapolating data from
long-term animal studies to humans, etc. In general, RfD values have an uncertainty
range of about one order of magnitude. Since slope factors represent an estimate of an
upper-bound lifetime probability of an individual developing cancer, these values are
8-2
-------
already conservative. Thus, the amount of uncertainty associated with slope factor values
may be minimal.
Toxicity values were not available for all of the chemicals detected In the Buffalo
River. For some chemicals, such as lead, a risk characterization could not be done
because toxicity values have not been derived yet or else are under review by EPA
workgroups. In addition, a RfD value has not been listed yet for PCBs in IRIS; thus,
noncarcinogenic risks from exposure to PCBs could not be determined. For a-chlordane
and y-chlordane, both chemicals were assumed to have the same toxicity factors as total
chlordane. The uncertainty of not being able to include some chemicals in this risk
assessment is unknown.
A conservative assumption for metal speclatlon In the lower Buffalo River was made
for chromium and mercury because toxicity values for the total metal forms were not
available. Thus, toxicity values for chromium VI and methyl mercury were applied to
represent the major forms of chromium and mercury, respectively. The use of this more
toxic chemical species results in a conservative estimate of risk. A moderate level of
uncertainty is probably associated with this assumption.
8.2.4 Risk Characterization
The uncertainties associated with the risk characterization step are listed below.
Exposure Intakes and toxicity values will remain the same over the exposure duration.
This assumes that human activities and contaminant levels will remain the same over the
exposure duration, and that toxicity values will not be updated. A moderate to high level
of uncertainty is probably associated with this assumption since it does not take into
consideration the implementation of remedial actions or the deposition of cleaner
sediments over contaminated sediments. Furthermore, toxicity values are frequently
updated in the IRIS data base as new information becomes available. The level of
uncertainty will probably increase with longer exposure durations.
Health risks are additive for both noncarcinogenic and carcinogenic effects. The
uncertainty associated with this assumption is unknown. The toxicity exhibited by a
mixture of chemicals may involve synergistic and antagonistic effects. However, no
guidelines are available to judge the complex interactions a mixture of contaminants may
possess in terms of its potential toxicity to humans. At the present time, standard risk
assessment guidance assumes that health risks are additive.
The risk characterization only Included substances for which data were available.
The potential contribution of other substances expected to be present is unknown.
8.3 SUMMARY
Based on the current information available, a complete description of the level of uncertainty associated
with all of the assumptions and data used in this risk assessment cannot be made. This baseline human
health risk assessment was based on data and assumptions that, in reality, represent a snapshot in time.
One of the greatest sources of uncertainty in this risk assessment arises from assuming that estimated
8-3
-------
risks will remain constant over the exposure duration (i.e., 9 years for typical exposures and 30 years for
reasonable maximum and subsistence exposures). The overall uncertainty of the risk estimates probably
varies by over an order of magnitude. As additional data are collected from the Buffalo River and as
additional (or revised) toxicity values are generated, a better estimate of human health risk can be
determined for people living in this area. In particular, the inclusion of other fish species that are likely
to be consumed by anglers would be useful. The uncertainty of updated risk assessments would likely
decrease as new information becomes available.
8-4
-------
REFERENCES
Batterman, A.R., P.M. Cook, KB. Lodge, D.B. Lothenbach, and B.C. Butterworth. 1989. Methodology
Used for a Laboratory Determination of Relative Contributions of Water, Sediment and Food Chain
Routes of Uptake for 2,3,7,8-TCDD Bioaccumulation by Lake Trout in Lake Ontario.
Chemosphere. 19:451-458.
Bierman, V.J., Jr. 1990. Equilibrium Partitioning and Biomagnification of Organic Chemicals in Benthic
Animals. Environ. Sci. Technol. 24:1407-1412.
Black, J.J., H. Fox, P. Black, and F. Bock. 1985. Carcinogenic Effects of River Sediment Extracts in Fish
and Mice. In: Water Chlorination Chemistry, Environmental Impacts, and Health Effects. Lewis
Publishers, Inc.
Borgmann, U. and D.M. Whittle. 1991. Contaminant Concentration Trends in Lake Ontario Lake Trout
(Salvelinus namavcush): 1977 to 1988. J. Great Lakes Res. 17:368-381.
Bro, K.M. 1989. Setting Priorities for Investigating Chemical Contaminants in the Great Lakes. Ph.D.
thesis. University of Wisconsin-Madison.
Brown, M.P., M.B. Werner, R.J. Sloan, and K.W. Simpson. 1985. Polychlorinated Biphenyls in the Hudson
River. Environ. Sci. Technol. 19:656-661.
Connor, M.S. 1984. Fish/Sediment Concentration Ratios for Organic Compounds. Environ. Sci. Technol.
18:31-35.
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.
U.S. 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 Canal,
Indiana, Area of Concern. EPA-905-xxx-xxx. U.S. Environmental Protection Agency, Environmental
Research Laboratory, Athens, GA. (awaiting EPA number).
9-1
-------
Crane, J.L 1993. A Baseline Assessment of Human Health Risks Resulting from PCB Contamination at
the Sheboygan River, Wisconsin, Area of Concern. EPA-905-R93-001. U.S. Environmental
Protection Agency, Environmental Research Laboratory, Athens, GA.
Foran, J.A. and D. VanderPloeg. 1989. Consumption Advisories for Sport Fish in the Great Lakes Basin:
Jurisdictional Inconsistencies. J. Great Lakes Res. 15:476-485.
Gill, G.A. and K.W. Bruland. 1990. Mercury Speciation in Surface Freshwater Systems in California and
other Areas. Environ. Sci. Technol. 24:1392-1400.
Henderson, B.E., R.K. Ross, and M.C. Pike. 1991. Toward the Primary Prevention of Cancer. Science.
254:1131-1138.
Hicks, H. 1993. Personal communication (letter to J.L Crane, EVS Consultants, North Vancouver, B.C.
regarding information on the ATSDR Great Lakes Human Health Effects Research Program).
Department of Health and Human Services, Agency for Toxic Substances and Disease Registry,
Atlanta, GA. 2 pp. + attachments. Received 15 October.
Jaffe, R., E.A. Stemmler, B.D. Eitzer, and R.A. Hites. 1985. Anthropogenic, Polyhalogenated,
Organic Compounds in Sedentary Fish from Lake Huron and Lake Superior Tributaries
and Embayments. J. Great Lakes Res. 11:156-162.
Kononen, D.W. 1989. PCBs and DDT in Saginaw Bay White Suckers. Chemosphere. 18:2065-2068.
Kuehl, D.W., P.M. Cook, A.R. Batterman, D. Lothenbach, and B.C. Butterworth. 1987. Bioavailability of
Polychlorinated Dibenzo-p-dioxins and Dibenzofurans from Contaminated Wisconsin River
Sediment to Carp. Chemosphere. 16:667-679.
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.
Lee, C.R., D.L Brandon, J.W. Simmers, H.E. Tatem, and J.G. Skogerboe. 1991. Information Summary,
Area of Concern: Buffalo River, New York. Miscellaneous Paper EL-91-9, U.S. Army Engineer
Waterways Experiment Station, Vicksburg, MS.
Malins, D.C., B.B. McCain, D.W. Brown, S-L Chan, M.S. Myers, J.T. Landahl, P.G. Prohaska, A.J.
Friedman, LD. Rhodes, D.G. Burrows, W.D. Gronlund, and H.O. Hodgins. 1984. Chemical
Pollutants in Sediments and Diseases of Bottom-dwelling Fish in Puget Sound, Washington.
Environ. Sci. Technol. 18:705-713.
9-2
-------
Mueller, M.E. 1992. Ashtabula River and Buffalo River Tumor Surveys for "Assessment and Remediation
of Contaminated Sediments' (ARCS). U.S. Fish and Wildlife Service, National Fisheries and
Wildlife Service, National Fisheries Research Center-Great Lakes, Ann Arbor, Ml. 19 pp.
New York State Department of Health. 1989. Health Advisories: Chemicals in Sportfish or Game. New York
State Department of Health, Division of Environmental Health Assessment, Albany, NY.
NYSDEC. 1989. Buffalo River Remedial Action Plan. New York State Department of Environmental
Conservation, Albany, NY.
Oliver, B.G. and A.J. Niimi. 1988. Trophodynamic Analysis of Polychlorinated Biphenyl Congeners and
other Chlorinated Hydrocarbons in the Lake Ontario Ecosystem. Environ. Sci. Technol. 22:388-
397.
Pizza, J.C. and J.M. O'Connor. 1983. PCB Dynamics in Hudson River Striped Bass. II. Accumulation
from Dietary Sources. Aquatic Toxicol. 3:313-327.
Seelye, J.G., R.J. Hesselberg, and M.J. Mac. 1982. Accumulation by Fish of Contaminants Released from
Dredged Sediments. Environ. Sci. Technol. 16:459-464.
Skinner, LC. and S.J. Jackling. 1989. Chemical Contaminants in Young-of-the-Year Fish from New York's
Great Lakes Basin: 1984 through 1987. New York State Department of Environmental
Conservation, Division of Fish and Wildlife, Bureau of Environmental Protection, Albany, NY.
Smith, W.E., K. Funk, and M.E. Zabik. 1973. Effects of Cooking on Concentrations of PCB and DDT
Compounds in Chinook (Oncorhvnchus tshawvtscha) and Coho (O. kisutch) Salmon from Lake
Michigan. J. Fish. Res. Board Can. 30:702-706.
Spigarelli, S.A., M.M. Thommes, and W. Prepejchal. 1983. Thermal and Metabolic Factors Affecting PCB
Uptake by Adult Brown Trout. Environ. Sci. Technol. 17:88-94.
Stachiw, N., M.E. Zabik, A.M. Booren, and M.J. Zabik. 1988. Tetrachlorodibenzo-p-dioxin Residue
Reduction through Cooking/Processing of Restructured Carp Fillets. J. Agric. Food Chem.
36:848-852.
Swackhamer, D.L and R.A. Hites. 1988. Occurrence and Bioaccumulation of Organochlorine
Compounds in Fishes from Siskiwit Lake, Isle Royale, Lake Superior. Environ. Sci. Technol. 22:
543-548.
9-3
-------
Swain, W.R. 1991. Effects of Organochlorine Chemicals on the Reproductive Outcome of Humans who
Consumed Contaminated Great Lakes Fish: an Epidemiologic Consideration. J. Toxicol. Environ.
Health. 33:587-639.
Thomann, R.V. and J.P. Connolly. 1984. Model of PCB in the Lake Michigan Lake Trout Food Chain.
Environ. Sci. Technol. 18:65-71.
U.S. EPA. 1988a. Risk Management Recommendations for Dioxin Contamination at Midland, Michigan.
Final Report. EPA Region 5, Chicago, IL EPA-905/4-88-008.
U.S. EPA. 1988b. Superfund Exposure Assessment Manual. Office of Remedial Response, Washington,
DC. EPA/540/1-88/001.
U.S. EPA. 1989a. Risk Assessment Guidance for Superfund: Human Health Evaluation Manual Part A.
Interim Final. OSWER Directive 9285.7-01 a.
U.S. EPA. 1989b. Exposure Factors Handbook. Office of Health and Environmental Assessment,
Washington, DC. EPA/600/8-89/043.
U.S. EPA. 1989c. Health Effects Assessment Summary Tables. Fourth Quarter, FY 1989. OERR 9200.6-
303-(89-4).
U.S. EPA. 1989d. Interim Policy for Estimating Carcinogenic Risks Associated with Exposures to
Polycyclic Aromatic Hydrocarbons (PAHs). OSWER Directive #9285.4-02. (Contained in
Memorandum from H.L Longest and B. Diamond to Region Directors).
U.S. EPA. 1991 a. 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.
U.S. EPA. 1991b. ARCS: Assessment and Remediation of Contaminated Sediments. 1991 Work Plan.
Great Lakes National Program Office, Chicago, IL
U.S. EPA. 1993. Guidance for Assessing Chemical Contaminant Data for Use in Fish Advisories. Volume
I. Fish Sampling and Analysis. Office of Water, Washington, DC. EPA 823-R-93-002.
Vena, J.E. 1992. Preliminary Findings from the New York State Angler Cohort Study. Perspectives: Great
Lakes Program. 6:1,3-5.
9-4
-------
Vena, J.E. 1993. Personal communication (letter to J.L Crane, EVS Consultants, North Vancouver, B.C.
regarding New York State Angler Cohort Study). Department of Social and Preventive Medicine,
University at Buffalo, State University of New York. 1 p. + attachments. 10 September.
Weininger, D. 1978. Accumulation of PCBs by Lake Trout in Lake Michigan. Ph.D. thesis. University of
Wisconsin-Madison, Madison, Wl.
West, P.C., J.M. Fly, R. Marans, and F. Larkin. 1989. Michigan Sport Anglers Fish Consumption Survey.
University of Michigan School of Natural Resources, Natural Resource Sociology Research Lab
Technical Report #1, Ann Arbor, Ml.
West, P.C., J.M. Fly, R. Marans, F. Larkin, and D. Rosenblatt, undated. Toxic Discharge Standards, Fish
Consumption and the Elderly. Research paper. School of Natural Resources and Institute of
Gerontology, University of Michigan, Ann Arbor, Ml. 23 pp.
Zabik, M.E. 1974. Polychlorinated Biphenyl Levels in Raw and Cooked Chicken and Chicken Broth.
Poultry Sci. 53:1785-1790.
Zabik, M.E. 1990. Effect of Roasting, Hot-holding, or Microwave Heating on Polychlorinated Biphenyl
Levels in Turkey. School Food Service Res. Rev. 14:98-102.
Zabik, M.E., P. Hoojjat, and C.M. Weaver. 1979. Polychlorinated Biphenyls, Dieldrin and DDT in Lake
Trout Cooked by Broiling, Roasting or Microwave. Bull. Environm. Contam. Toxicol. 21:136-143.
Zabik, M.E., C. Merrill, and M.J. Zabik. 1982. PCBs and Other Xenobiotics in Raw and Cooked Carp.
Bull. Environm. Contam. Toxicol. 28:710-715.
9-5
-------
APPENDIX A
ESTIMATING POLLUTANT CONCENTRATIONS IN SURFACE WATER
The following section was extracted from Laniak et al. (1992). This section describes how surface water
concentrations of organic contaminants were estimated from sediment concentrations and equilibrium
partitioning relationship.
The approach taken for estimating the concentration of organic compounds in surface water when
measured values fall below the detection limits is to represent the total concentration of an organic
pollutant in surface water as the combination of pollutant adsorbed to suspended particles and in
aqueous solution. The total contaminant concentration in the water column can be taken as the sum of
the participate associated and dissolved fractions. This total may be described by:
C = — + C TSS
where C, is the total contaminant concentration (dissolved plus paniculate), C, is the sorbed concentration
(mg contaminant/kg solids), Kp is a partition coefficient (L/kg-solids), and TSS is the suspended solids
concentration (kg-solids/L). The dissolved concentration (assuming equilibrium partitioning) may be
estimated from 0,/Kp and the participate concentration may be estimated from C, TSS. The dissolved
fraction and paniculate water column fraction of the chemical, as well as the total chemical concentration,
can, therefore, be estimated if one knows the sediment sorbed concentration, the partition coefficient, and
the concentration of suspended solids in the water column. The estimate of total concentration derived
using the above formula is considered to be conservative since it is assumed that there is an equilibrium
between the sediments and the water column and that the materials in the water column are not reduced
due to outflows or to chemical/biological degradation (e.g., photolysis).
For hydrophobic organic compounds (HOCs) where water quality data were not determined or where
measurements were below a specified detection limit, it was necessary to provide estimates of water
concentrations using the method described above. The calculation requires estimation of the partition
coefficient (Kp).
The water-panicle partition coefficient, Kp, is more aptly described as a distribution coefficient, K,,, in field
situations where complete equilibrium may not be achieved. K,, can be normalized by f^. (the organic
carbon fraction) to yield K^, the amount of organic contaminant adsorbed per unit weight of organic
carbon in soil or sediment. Thus, K^ = KJ1X. Relationships between K^. and K^, (the octanol-water
partition coefficient) have been derived based on laboratory experiments of the sorption of organic
chemicals with freshwater sediments and soils (Karickhoff et al., 1979; Kenaga and Goring, 1980; Means
A-1
-------
et al., 1980; Brown and Flagg, 1981; Karickhoff, 1981; Schwarzenbach and Westall, 1981; Chiou et al.,
1983). These laboratory investigations have demonstrated the importance of the organic fraction of
sediments in controlling the equilibrium aqueous concentrations of sorbed chemicals.
The empirical relationship developed by Karickhoff and co-workers (1979) [i.e., K^ = 0.63 K^ (r2 = 0.96)]
was based on experiments using a variety of chemicals (e.g., anthracene, naphthalene, phenanthrene,
pyrene, and one PCB congener). Since these chemicals were also part of the 31 chemical data set
examined for the Buffalo River, the aforementioned relationship was applied to the Buffalo River data set
by substituting KJ1X for K,,,.. Thus, the following relationship was obtained:
0.63 K
m
Table A.1 provides a list of estimated ^s for the 31 chemical contaminants included in this study. In
addition, the parameters used to make these estimates (i.e., K
-------
TABLE A.1. ESTIMATED PARTITION COEFFICIENTS
Chemical
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(ghi)perylene
Benzo(k)fluoranthene
Chrysene
Dibenzo(a,h)anthracene
Fluoranthene
Fluorene
lndeno(1 ,2,3-cd)pyrene
Naphthalene
Phenanthrene
Pyrene
alpha-BHC
beta-BHC
Lindane
Aldrin
Chlordane
Dieldrin
Endrin
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Mirex
ODD
DDE
DDT
PCBs
Log
Kow
4
3.7
4.5
5.6
6.1
6.1
6.5
6.1
5.6
6.8
4.9
4.2
6.5
3.3
4.5
4.9
3.9
3.9
3.9
5.3
3.3
3.5
5.3
4.4
2.7
5.2
7.4
6.2
7
6.2
6.0
Kow
1.00E+04
5.01 E+ 03
2.82E+04
3.98E+05
1.15E+06
1.15E+06
3.24E+06
1.15E+06
4.07E+05
6.31 E+06
7.94E+04
1.58E-I-06
3.16E+06
1.95E+03
2.88E+04
7.59E+04
7.94E+03
7.94E+03
7.94E+03
2.00E+05
2.00E+03
3.16E+03
2.18E+05
2.51E+04
5.01 E+02
1.58E+05
2.51 E+07
1.58E+06
1.00E+07
1.55E+06
1.10E+06
Calculated
Koc
6.30E+03
3.16E+03
1.78E+04
2.51 E+ 05
7.23E+05
7.23E+05
2.04E+06
7.23E+05
2.75E+05
3.98E+06
5.00E+04
9.98E+03
1.99E+06
1.23E+03
1.82E+04
4.78E+04
5.00E+03
5.00E+03
5.00E+03
1.26E+05
1.26E+03
1.99E+03
1.37E+05
1.58E+04
3.16E+02
9.98E+04
1.58E+07
9.98E+05
6.30E+06
9.76E+05
6.91 E+05
Calculated
Kd
7.9
4.0
22.4
316
911
911
2570
911
323
5010
63.1
12.6
2510
1.5
22.9
60.2
6.3
6.3
6.3
158
1.6
2.5
173
19.9
0.4
126
19900
1260
7940
1230
870
A-3
-------
TABLE A.2. MEAN CONTAMINANT CONCENTRATIONS IN SEDIMENTS SAMPLES COLLECTED IN 1989*
Chemical
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(ghi)perylene
Benzo(k)fluoranthene
Chrysene
Dibenzo(a,h)anthracene
Fluoranthene
Fluorene
lndeno(1,2,3-cd)pyrene
Naphthalene
Phenanthrene
Pyrene
alpha-BHC
beta-BHC
Lindane (gamma-BHC)
Aldrin
Chlordane
Dieldrin
Endrin
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Mirex
p.p'-DDD
p.p'-DDE
p.p'-DDT
PCBs (total)
ND = Not Detected
Mean Sediment
Concentrations
(mg/kg)
ND
ND
1.80E-01
6.10E-01
9.50E-01
1.65E+00
4.50E-01
ND
6.90E-01
ND
1.57E+00
3.30E-01
4.50E-01
3.10E-01
7.70E-01
9.30E-01
ND
ND
ND
ND
ND
ND
ND
ND
4.00E-02
ND
ND
ND
ND
ND
ND
Sediment sampling was performed in the Buffalo Harbor area during 1989 by
Aqua Tech Environmental Consultants, Inc., under contract to the U.S. Army
Corps of Engineers - Buffalo District.
A-4
-------
TABLE A.3. ESTIMATED WATER COLUMN CONCENTRATIONS
Chemical
Mean 1989
Water Concentrations
(mg/L)
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(ghi)perylene
Benzo(k)fluoranthene
Chrysene
Dibenzo(a, h) anthracene
Fluoranthene
Fluorene
lndeno(1,2,3-cd)pyrene
Naphthalene
Phenanthrene
Pyrene
alpha-BHC
beta-BHC
Lindane (gamma-BHC)
Aldrin
Chlordane
Dieldrin
Endrin
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Mirex
p,p'-DDD
p.p'-DDE
p.p'-DDT
PCBs (total)
ND
ND
8.05E-03
1.94E-03
1.06E-03
1.84E-03
1.83E-04
ND
1.80E-03
ND
2.49E-02
2.62E-02
1.87E-04
3.00E-02
3.00E-02
1.55E-02
ND
ND
ND
ND
ND
ND
ND
ND
1.00E-02
ND
ND
ND
ND
ND
ND
ND = Not Detected
A-5
-------
Kenaga, E.E. and C.A.I. Goring. 1980. Relationship Between Water Solubility, Soil Sorption, Octanol-
Water Partitioning, and Concentration of Chemicals in Biota, p. 78-115. In Aquatic Toxicology
(STP-707). J.G. Eaton, P.R. Parrish, and A.C. Hendricks, Eds. American Society for Testing and
Materials. Philadelphia, PA. 405 pp.
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.
Means, J.C., S.G. Wood, J.J. Hassett, and W.L Banwart. 1980. Sorption of Polynuclear Aromatic
Hydrocarbons by Sediments and Soils. Environ. Sci. Technol. 14:1524-1528.
Schwarzenbach, R.P. and J. Westall. 1981. Transport of Nonpolar Organic Compounds from Surface
Water to Groundwater: Laboratory Sorption Studies. Environ. Sci. Technol. 15:1360-1367.
A-6
-------
APPENDIX B
HUMAN TOXICITY ESTIMATES FOR CONTAMINANTS PRESENT IN THE
BUFFALO RIVER AREA OF CONCERN
B.1 TOXICITY ASSESSMENT
The toxicity assessment step is an integral part of the human health baseline risk assessment. This step
includes four tasks: (1) gather qualitative and quantitative toxicity information for substances being
evaluated, (2) identify exposure periods for which toxicity values are necessary, (3) determine toxicity
values [i.e., reference doses (RfDs)] for noncarcinogenic effects, and (4) determine toxicity values (i.e.,
slope factors) for carcinogenic effects (USEPA, 1989a). The EPA has performed the toxicity assessment
step for a limited number of chemicals and these assessments have undergone extensive peer review.
Therefore, the toxicity assessment step of this study involves primarily a compilation of available toxicity
data.
Once a "verified' toxicity value is agreed upon by the EPA's toxicologists, it is entered into the EPA's
Integrated Risk Information System (IRIS) data base; these values are updated as necessary. IRIS is the
primary source of toxicity information used in baseline risk assessments. The Health Effects Assessment
Summary Tables (HEAST) are the second most current source of toxicity information and include both
verified and interim RfD and slope factor values. Interim values are used for chemicals that have not yet
been approved by the EPA. Specific EPA workgroups, such as the Carcinogen Risk Assessment
Verification Endeavor (CRAVE) and RfD Workgroups, are another source of interim toxicity values. If
toxicity values are not available in the aforementioned sources, then interim values from other reports may
be used.
This appendix summarizes pertinent toxicity information obtained from IRIS and other sources for
chemicals in the lower Buffalo River. Also included in this appendix are brief descriptions of the most
important toxicity values used to evaluate noncarcinogenic and carcinogenic effects; these subsections
were summarized from the EPA guidance document: "Risk Assessment Guidance for Superfund. Volume
1. Human Health Evaluation Manual (Part A)' (USEPA, 1989a).
B.1.1 Noncarcinogenic Chronic Toxicity
The RfD is the toxicity value used most often in evaluating noncarcinogenic effects. RfDs are based on
the assumption that thresholds exist for certain toxic effects (e.g., cellular necrosis) but may not exist for
other toxic effects (e.g., carcinogenicity). The RfD is defined as an estimate of the daily exposure to the
human population that is likely to be without an appreciable risk of deleterious effects during either a
B-1
-------
portion of the lifetime (i.e., subchronic RfD or "RfD,') or during the lifetime (i.e., chronic RfD or "RfD"). This
toxicity value has an uncertainty range of about an order of magnitude and includes exposures to
sensitive subgroups in the population. For each chemical, the RfD is calculated from the following
equation:
Ofn NOAEL or LOAEL
Rf° UFXMF
where:
NOAEL = No-Observed-Adverse-Effect-Level
LOAEL = Lowest-Observed-Adverse-Effect-Level
MF = Modifying Factor
U = Uncertainty Factor
The NOAEL and LOAEL are derived from dose-response experiments. The NOAEL represents the highest
exposure level tested at which no adverse effects occurred (including the critical toxic effect), whereas
the LOAEL represents the lowest exposure level at which significant adverse effects occurred. Uncertainty
factors usually consist of multiples of ten, with each factor representing a specific area of uncertainty
included in the extrapolation from available data. An uncertainty factor of ten is usually used to account
for variation in the general population so that sensitive subpopulations are protected. An additional ten-
fold factor is usually applied for each of the following extrapolations: from long-term animal studies to
humans, from a LOAEL to a NOAEL, and when subchronic studies are used to derive a chronic RfD. A
modifying factor (MF), ranging from >0 to 10, is included as a qualitative assessment of additional
uncertainties; the default value for the MF is one.
Table B-1 includes the uncertainty and modifying factors, confidence classifications, and critical effects
of the contaminants examined for this risk assessment. Uncertainty factors ranged from 3 to 1000, and
either a low or medium level of confidence was given for these RfD values. Better estimates of oral RfD
values are needed to reduce these levels of uncertainty.
B.1.2 Carclnogeniclty
Human carcinogenic risks are usually evaluated for a chemical by using its slope factor (formerly
designated as a cancer potency factor) and corresponding weight-of-evidence classification. These
variables were listed in Table 6.2 for the Buffalo River chemicals. 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. The slope factor is characterized as an upper-bound estimate so that the true
risk to humans, while not identifiable, is not likely to exceed the upper-bound estimate.
The weight of evidence classification for a particular chemical is determined by the EPA's Human Health
Assessment Group (HHAG). Chemicals are placed into one of five groups according to the weight of
B-2
-------
TABLE B-1. ORAL RfD SUMMARY FOR CHEMICALS LISTED IN IRIS AS OF 21 JULY 1993
Chemical
METALS
Cadmium
Chromium VI
Manganese
Mercury, methyl
Nickel
Silver
Zinc
PAHs
Anthracene
Fluoranthene
Ruorene
Pyrene
ORGANOCHLORINE INSECTICIDES
Chlordane
Dteldrin
Heptachlcr epoxide
p,p' DDT
MF
1
1
1
1
1
1
1
1
Confidence
in Oral
RfD
High
Low
Medium
Medium
Medium
Low
Medium
Low
Low
Low
Low
Low
Medium
Low
Medium
Critical Effects
Significant proteinuria in humans
No effects reports in rats
Cental nervous system effects In humans
Cental nervous system effects in humans
Decreased body and organ weights in rats
Argyria In humans
47% decrease in erythrocyle superoxide dismutase
(ESOD) concentration in adult woman
No observed effects in mice
Nephropathy, increased liver weights.
hematological alterations, and clinical effects in mice
Decreased Red Blood Cells, packed cell volume and
hemoglobin in mice
Kidney effects (remal tubular pathology, decreased
kidney weights) in mice
Regional liver hypertrophy in female rats
Uver lesions in rats
Increased liver-to-body weight ratio in both males
and females in dogs
Liver lesions in rats
evidence from epidemiological studies and animal studies. These groups are designated by the letters
A, B, C, D, and E which represent the level of carcinogenicity to humans (see Table 6.1). Quantitative
carcinogenic risk assessments are performed for chemicals in Groups A and B, and on a case-by-case
basis for chemicals in Group C.
B.2 UNCERTAINTIES
A number of uncertainties are involved with using toxicity values for estimating noncarcinogenic and
carcinogenic risks. Some of these qualitative uncertainties are listed below:
• Using dose-response information from healthy animal or human populations to predict
effects that may occur in the general population, including susceptible subpopulations
(e.g., elderly, children),
• Using dose-response information from animal studies to predict effects that may occur
in human populations,
B-3
-------
Using NOAELs derived from short-term animal studies to predict effects that may occur
in humans during long-term exposures,
Using dose-response information from effects observed at high doses to predict the
adverse health effects that may occur following exposure of humans to low levels of the
chemical in the environment, and
Using a toxicity value derived from exposure to a particular chemical mixture (e.g., Aroclor
1260) to represent the level of toxicity for other similar chemical mixtures (e.g., Aroclor
1242, 1248, and 1254).
B-4
------- |