United States Region 10 Alaska 

Environmental Protection 1200 Sixth Avenue Idaho 

Agency Seattle WA 98101 Oregon 

Washington 

August 2007 

Framework for Selecting and Using Tribal Fish and 

Shellfish Consumption Rates for Risk-Based 

 Decision Making at CERCLA and RCRA Cleanup 

 Sites in Puget Sound and the Strait of Georgia 

 

Working Document

To Be Applied in Consultation with Tribal Governments 

on a Site-specific Basis 

Revision 00 

Office of Environmental Cleanup 

Office of Air, Waste and Toxics 

Office of Environmental Assessment
ii

This Framework is not intended to replace government-to-government consultation on 

specific sites. EPA’s release of the Framework does not imply concurrence by the 

Tribes. Nothing in this Framework will limit, modify, or change Tribal treaty rights. 
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Table of Contents

 Page 

Executive Summary 1 

 

I. Introduction 3 

 

II. Application of the Framework 4 

III. Key Considerations 6 

IV. Steps for Selecting the Tribal Fish and Shellfish Consumption Rate 13 

V. Selection of Species for Collection of Chemical Contaminant Data and 

 Derivation of Exposure Point Concentrations when Data for Multiple 

Species within a Species Group are Available 19 

VI. Uncertainties 22 

VII. Risk Communication and Risk Management Issues 27 

XIII. Five-Year Review Considerations 28 

IX. References 30 

Flow Sheet [Note: The Flow Sheet is included as a separate file in electronic copies 

 of the Framework.] 

Step 1: Select Basis for Tribal Fish and Shellfish Consumption Rate 

Step 2: Select Fish and Shellfish Consumption Rate and Consideration of 

 Site- related Contaminants

Appendices 

A: Development of the Framework for Selecting and Using Tribal Fish and 

Shellfish Consumption Rates for Risk-Based Decision Making at CERCLA 

and RCRA Cleanup Sites in Puget Sound and the Strait of Georgia 

B: Fish and Shellfish Mixtures from Tribal-Specific Consumption Studies 

 

C: Background Information on the Calculation of Fish and Shellfish 

 Consumption Rates. 

D: Section IV Applied to a Simple Hypothetical Site 
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1

Executive Summary 

 This document presents a conceptual Framework for selecting and using Tribal fish and 

shellfish consumption rates for purposes of estimating site-related risks at U.S. Environmental 

Protection Agency (EPA) hazardous waste cleanup sites in Puget Sound and the portion of the 

Strait of Georgia that is within the United States. It is specifically intended for use at sites that 

are addressed through the Resource Conservation and Recovery Act (RCRA) and the 

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, also 

known as Superfund.) EPA will consult with Tribes on site-specific exposure assumptions and 

cleanup decisions at each Superfund and RCRA site within a Tribal fishing area or on Tribal 

land. The Framework’s function is to assist EPA Region 10 staff in managing RCRA and 

CERCLA cleanups in consideration of information that reflects Tribal exposures and concerns. 

 The Framework is not intended to replace government-to-government consultation on 

specific sites. EPA’s release of the Framework does not imply concurrence by the Tribes. 

Nothing in this Framework will limit, modify, or change Tribal treaty rights. 

 One of the numerous pieces of information needed to estimate potential human health 

risks due to chemical contamination at cleanup sites is exposure to site-related contamination via 

consumption of fish and shellfish. Consumption of locally harvested fish and shellfish by 

American Indians is likely to be higher than it is for the general U.S. population. Consumption 

rates may be drawn from various sources. In this document, highest preference is given to 

consumption rates derived from well-designed consumption surveys of Puget Sound Tribes, 

and lowest preference to default values from nationwide food intake studies. Local consumption 

rate data (95th percentile, uncooked weight, harvested from Puget Sound) were derived from fish 

and shellfish consumption studies for the Suquamish Tribe and the Tulalip Tribes. Consumption 

rates derived from the Suquamish Tribe data are most applicable to cleanup sites with extensive 

intertidal habitat capable of sustained shellfish harvest. Consumption rates derived by EPA from 

the Tulalip Tribes data are more applicable where such habitat is not extensive. In addition, 

where a Tribal-specific survey exists and where a cleanup site is within that Tribe's exclusive 

usual and accustomed harvesting areas, the fish consumption exposure scenarios should include 

the consumption rate based on that Tribe's survey data. 

 Site-specific and Tribal-specific factors should be considered when applying the 

Framework. If justifiable, specific chemicals may be excluded from the estimates of site-related 

risks. For example, chemicals may be excluded if they do not accumulate in a particular type of 

locally harvested fish and shellfish, or if the chemicals are unrelated to the site. Modification of 

exposure assumptions may be appropriate for exposure duration and consumer body weight, 

depending upon availability of data for the potentially exposed Tribal population. In this 

Framework, it is assumed that Tribal members substitute different types of fish and shellfish 

when those that would preferentially be harvested are unavailable. 
2

 Uncertainties are inherent in all risk assessments, including those performed using this 

Framework. A number of those uncertainties are summarized in the Framework. Site-specific 

risk characterizations should include a description of uncertainties and their potential effects on 

estimated risks. 
3

I. Introduction

Potential human health risks1

 due to chemical contamination are among the many factors 

that affect EPA Region 10’s cleanup decisions at RCRA and CERCLA sites in Puget Sound and 

the portion of the Strait of Georgia that is within the United States. Many CERCLA and RCRA 

cleanup sites located in EPA Region 10 have contaminated sediments or surface water, or 

include upland soil and groundwater that may release hazardous substances or hazardous 

constituents to sediment and surface water. Contaminants in sediments and surface water may 

then contaminate fish and shellfish. One of the inputs needed to calculate human health risks is 

exposure to contaminants via consumption of fish and shellfish. On the basis of data from the 

few fish and shellfish consumption surveys by or of American Indian Tribes within Region 10, 

Tribal consumption rates at cleanup sites within reservation lands or Tribal usual and 

accustomed harvesting areas2 (U&A) are likely to be higher than for the general U.S. population. 

The National Congress of American Indians (2004) published a resolution calling for EPA to 

“use fish and shellfish consumption rates appropriate to Tribal consumers when it makes cleanup 

decisions.” Modifications to standard risk assessment assumptions thus may be warranted. This 

document presents a conceptual Framework for selecting Puget Sound and the Strait of Georgia 

Tribal fish and shellfish consumption rates. 

Risk assessment is the process used by EPA to estimate the degree of risk posed by 

exposure to site-related chemical contaminants. It is also used to develop preliminary cleanup 

goals. Risk management is a subsequent agency process that deals with decisions regarding how 

much of the contaminant should be removed from the environment, based on considerations of 

background concentrations, site-specific contributions, human health and ecological impacts, 

cost-effectiveness of remedial options, and state, Tribal and community input. By Federal law, 

Superfund and RCRA risk assessments and selection of remedies must be protective of human 

health and the environment. 

The Framework provides a recommended approach for selecting fish and shellfish 

consumption rates where Tribal consumption of fish and shellfish from Puget Sound and the 

Strait of Georgia is evaluated in EPA’s risk assessment process for RCRA and CERCLA sites. 

The approach reflects existing EPA guidance and policies regarding the exposures due to 

releases from contaminated sites. This Framework is designed to provide a consistent approach 

to developing fish and shellfish consumption rates and to assist decision makers with risk 

management decisions. The process used to develop this Framework is summarized in 

Appendix A. 

1

 The term “risk” in this Framework primarily is used to generically describe both excess cancer risks and noncancer 

hazards. Where quantitatively addressed, cancer risks and noncancer hazards are distinguished. 

2

 Usual and accustomed harvesting areas is a term described by the Northwest Indian Fisheries Commission, at 

http://www.nwifc.wa.gov/shellfish/faq.asp. 
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II. Application of the Framework 

This Framework is intended to be applicable at EPA cleanup sites within Puget Sound 

and the Strait of Georgia. It does not attempt to include risks from all fish and shellfish 

consumed by Tribal members, but only that portion potentially affected by contaminants released 

at a cleanup site. 

 The fish and shellfish consumption data used in this Framework are derived from two 

Tribes in Puget Sound: the Suquamish Tribe (Suquamish Tribe, 2000) and the Tulalip Tribes 

(Toy et al., 1996). The studies were designed to include all Tribal members, not only 

“subsistence” consumers of fish and shellfish. Definitions of “subsistence” vary, but include 

“fishers who rely on noncommercially caught fish and shellfish as a major source of protein in 

their diets” (EPA, 2000c). 

Fish and shellfish consumption rates developed for risk assessments for the general U.S. 

population may not be adequately protective for other populations in Puget Sound and the Strait 

of Georgia. For example, rates of fish and shellfish consumption by Seattle-area Asians and 

Pacific Islanders in one study were higher than those of the general U.S. population (Sechena et 

al., 1999). However, this Framework does not address exposure assumptions for groups other 

than American Indians. It does not address ecological risks, which are typically evaluated 

separately when conducting a baseline risk assessment or establishing risk-based cleanup levels. 

As the Framework addresses only fish and shellfish consumption, other site-specific exposures to 

Tribal members, such as direct contact with contaminated sediment and surface water, also 

should be considered and evaluated. 

The Framework is a working document, to be modified as new information is acquired on 

Tribal consumption patterns, contaminant accumulation in fish tissues, and other scientific 

advances, or as agency policies change. The Framework’s function is to assist EPA Region 10 

staff in managing RCRA and CERCLA cleanups in consideration of information that reflects 

Tribal exposures and concerns. The Framework does not substitute for statutes EPA administers 

or their implementing regulations, nor does it hold the status of a regulation. Thus, it does not 

impose legally binding requirements on EPA, Tribes, states, or the regulated community. EPA 

Region 10 staff retains the discretion to use other scientifically defensible methods to select 

exposure assumptions on a case-by-case basis. 

Although CERCLA and RCRA share a common goal − to protect human health and the 

environment by cleaning up contaminated sites − they were mandated separately by Congress 

and follow different administrative procedures. This Framework is intended to be applied to 

future decisions in the RCRA and CERCLA programs. 

For baseline risk assessments, the Framework may be appropriate to use when 

contaminated soils, groundwater, surface water, or sediments may affect fish and shellfish 

harvested and consumed by Tribal members. At CERCLA sites where a remedy is required, the 

Framework may be used to evaluate various remedial alternatives. At RCRA sites where interim 
5

or final corrective measures are necessary, the Framework may be used in the development of 

risk-based cleanup levels. 

In keeping with EPA Region 10's Tribal Consultation Framework (EPA, 2001), EPA will 

continue to consult with Tribes on site-specific exposure assumptions and cleanup decisions at 

each Superfund and RCRA site within a Tribal fishing area or on Tribal land. If only one Tribal 

fish consumption exposure scenario is analyzed, this Framework encourages development of that 

scenario using the exposure assumptions established herein. Additional exposure assumptions 

should be considered, if the Tribe believes they would better represent exposure of Tribal 

members. In addition, where a Tribal-specific survey exists and where a cleanup site is within 

that Tribe's exclusive U&A, the fish consumption exposure scenarios should include the 

consumption rate based on that Tribe's survey data. EPA expects site-specific consultation with 

Tribes on other issues related to the application of this Framework typically will occur. 

 This Framework is not intended to replace government-to-government consultation on 

specific sites. EPA’s release of the Framework does not imply concurrence by the Tribes. 

Nothing in the Framework will limit, modify, or change Tribal treaty rights. 

EPA risk assessments should include both central and high-end estimates of exposure 

(EPA, 2000d, 2002c). Risk assessments based on Tribal fish and shellfish consumption studies 

with sufficient information concerning the responses of individual consumers should generally 

use the consumption rate associated with the 95th percentile of adult fish and shellfish 

consumers. The 95th percentile represents an appropriate high-end exposure scenario, consistent 

with EPA’s Risk Assessment Guidance for Superfund, Volume I, Part A (EPA, 1989). 

EPA recognizes that the quantitative nature of the risk assessment process inadequately 

addresses the impacts of fish and shellfish chemical contamination on Tribal culture and 

lifeways. As part of EPA’s site-specific consultation, EPA will invite Tribes to provide a 

qualitative discussion of their perceptions as to how fish and shellfish chemical contamination 

has affected them. This information would be forwarded to EPA risk managers along with the 

quantitative risk assessment. 

An EPA Region 10 advisory inter-program review group will be established to review 

site-specific applications of this Framework, as needed and appropriate. 
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III. Key Considerations

For this Framework, several key factors affect the exposure parameters: 

! Hierarchy of preferred data sources 

! Current conditions as predictors of future conditions 

! Use of substitute fish and shellfish sources (“resource switching”) 

! Use of anadromous fish data 

! Use of child-specific consumption rates 

! Other exposure considerations 

A. Hierarchy of Preferred Data Sources

Ambient water quality criteria (AWQC) published by EPA serve as one basis for 

regulatory protection of surface water quality and human health. The agency’s methodology for 

deriving AWQC (EPA, 2000a, b) provided useful direction in the development of the 

Framework. 

The AWQC methodology (EPA, 2000a, b) ranks four types of consumption data, in 

order of preference, as reflected in the Flow Sheet (Step 1) of the Framework: 

! Fish and shellfish consumption surveys of local watersheds representative of the people 

being addressed for the particular water body 

! Fish and shellfish consumption surveys that reflect geography and population groups 

similar to those under evaluation 

! National food consumption surveys 

! Default values 

To address the first two tiers of this hierarchy, fish and shellfish consumption surveys of 

Puget Sound Tribes were reviewed. Two studies, one of the Tulalip and Squaxin Island Tribes (Toy 

et al, 1996) and one of the Suquamish Tribe (Suquamish Tribe, 2000) were available. For a number 

of reasons, EPA believes these studies were well designed. They consisted of personal interview 

surveys conducted by Tribal members that elicited fish and shellfish consumption information over 

the course of an entire year. Participants in the surveys reviewed for this Framework were randomly 

selected, providing an unbiased estimate of fish and shellfish consumption. Interviewers in the 

surveys were trained, enhancing the consistency and accuracy of survey administration and data 

recording. The surveys were pilot-tested to identify and address survey administration problems. 

Professional statisticians participated in survey design and data analyses. Transcription of data from 

paper to computer file format was quality controlled. 

Though not relevant to the studies EPA is using for this version of the Framework, other 

survey methodology types are sometimes used to estimate fish and shellfish consumption rates. 

Because of the issues discussed below, EPA Region 10 would prefer not to use survey data collected 
7

using these methods to develop Tribal fish and shellfish consumption rate estimates. Much of the 

following discussion is based on an EPA review of fish and wildlife survey methodologies (EPA, 

1998c). Other types of surveys commonly employed are mail and creel surveys. Mail surveys 

typically are limited to reports of types and amounts of fish caught, with no opportunity for question 

clarification or interviewer probing to obtain correct responses. Creel surveys are conducted by 

inspecting an angler’s catch in the field. Creel surveys have a number of issues, including: 

difficulties in eliciting year-round consumption information; difficulties in using visual aids or other 

materials to assist in quantifying consumption; inability to obtain a random, unbiased sample of the 

study population; the willingness of the interviewee to provide information in a field situation when 

the interviewee would rather be angling; and problems in relating an angler’s catch to consumption 

rates of the angler’s family and community. Creel surveys of Tribes typically are not conducted by 

Tribal members, which could decrease the comfort of interviewees and the probability of complete 

and accurate transmission of information. 

Because of the quality of the survey methodology used in the available Puget Sound Tribal 

studies, EPA believes that these studies are appropriate to use to develop Puget-Sound harvested fish 

and shellfish consumption rates. Further, EPA believes that the rates developed from the 

aforementioned studies should be used in preference to an estimate of an average subsistence 

consumption rate, as recommended in the EPA AWQC methodology (EPA, 2000a,b). Site-specific 

factors should enter into the process of selecting a consumption rate, as discussed in more detail in 

Section IV of the Framework. 

Where no Tribal-specific data are available for use, a non-Tribal fish consumption report 

based on nationwide studies with acceptable levels of scientific quality is Estimated Per CapitaFish Consumption in the United States (EPA, 2002a). It is of limited value in estimating long-term 

consumption rates for American Indians. The consumption rates reported in the document are from 

the combined 1994-1996 and 1998 Continuing Survey of Food Intakes by Individuals (CSFII), 

conducted by the U.S. Department of Agriculture. The CSFII surveys were designed and conducted 

to support unbiased estimation of food consumption across the United States, based on fish and 

shellfish consumption as reported by individuals during two non-consecutive days. EPA considers 

this methodology appropriate for estimating mean intake values of the U.S. population in general, 

based on fish and shellfish consumption reported by individual survey participants, but because of 

insufficient numbers of participants in certain populations, including American Indians, the fish 

consumption estimates are not considered to be representative of such populations. In the AWQC 

methodology (EPA 2000a, b), EPA recommends a default consumption rate for subsistence fishers, 

when local or regional data are unavailable. The 99th percentile consumption rate from the 1994-

1996 CSFII respondents who reported eating fish during the two-day survey period as well as those 

who reported not eating fish during that period fell within the range of average values for subsistence 

fishers, based on studies available at that time. The 99th percentile consumption rate for this group is 

215.7 g/day for all finfish and shellfish (EPA, 2002a). This Framework recommends using this value 

only when no Tribal-specific data are appropriate for use. 

Concerns have been expressed regarding the methodology used by EPA to establish the 

default AWQC subsistence fish consumption rates. In Fish Consumption and Environmental Justice
8

(EPA, 2002b), the National Environmental Justice Advisory Council (NEJAC), a federal advisory 

committee that provides independent advice, consultation, and recommendations to the EPA 

administrator on matters related to environmental justice, took issue with the use of a fish 

consumption rate for Tribes that includes survey respondents who reported eating no fish during the 

survey period. The report could be interpreted to call for using consumer-only rates from the CSFII 

surveys: 

EPA’s default values are based on per capita consumption rates from the general population 

- that is, “fish consumption” rates that include fish consumers and fish non-consumers alike. 

The CSFII study on which the EPA’s defaults are based for its Draft Methodology surveyed 

11,912 individuals annually for 3-day periods3

. Of the 11,912 participants, only 3,972 

actually ate fish during the three days surveyed. These were the fish consumers; their fish 

consumption rates were recorded. The 7,940 participants who didn't eat fish during the 

[survey] period were the fish nonconsumers; their fish consumption rates were entered as 

“0.” The CSFII study then generated two sets of figures: a set considering only the fish 

consumers and a set considering both the fish consumers and the fish nonconsumers. EPA 

chose to base its default values on the latter, per capita figures. Importantly, the effect of 

this choice is again to decrease the resulting default [fish consumption rates]- with so many 

“zero” values factored in, the point estimates are decreased at every point of comparison. 

So, for example, whereas the mean value for fish consumers is 106.39 g/day, the mean 

value once fish nonconsumers are also included sinks to 18.01 g/day; similarly, whereas the 

99th percentile value for fish consumers is 399.26 g/day, the 99th percentile value drops to 

142.96 g/day.4

B. Current Conditions as Predictors of Future Conditions 

Where Tribal members have already reduced their harvest of fish and shellfish from 

impaired habitat, the use of current consumption rates could result in underestimations of 

potential fish and shellfish consumption rates. As noted in the NEJAC report (EPA, 2002b): 

“A suppression effect occurs when a fish consumption rate for a given subpopulation 

reflects a current level of consumption that is artificially diminished from an appropriate 

baseline level of consumption for that subpopulation . . . When agencies set 

environmental standards using a fish consumption rate based upon an artificially 

diminished consumption level, they may set in motion a downward spiral whereby the 

resulting standards permit further contamination and/or depletion of the fish and aquatic 

resources.” 

Cleanup levels in the local aquatic environment, if they are based on current fish and 

3

 The survey period was decreased to two (non-consecutive) days as of the 1994 survey period. Previously, it was 

three days. 

4

 The value of 142.96 g/day in this quotation refers to freshwater and estuarine species only; 215.7 g/day is the 

comparable consumption rate that includes all fish, a combined value representing survey respondents who did and 

did not report eating fish on at least one day of the survey period. The 95th and 99th percentiles for survey 

respondents who reported eating fish on at least one day of the survey period are 333.8 and 518.7 g/day, respectively 

(EPA, 2002a). 
9

shellfish consumption rates in the vicinity of the cleanup site, may not reflect the potential for the 

water body to rebound from its current, relatively contaminated state. This should be considered 

when deciding whether the use of a surrogate Tribal fish and shellfish consumption rate would 

better represent potential future consumption rates than would consumption rates that represent 

only current or near-term contamination and habitat conditions. 

C. Use of Substitute Fish and Shellfish Resources

For purposes of the Framework, if certain species or types of fish and shellfish are not 

present, or will not be present in the future, Tribal members are assumed to substitute other 

species or types of fish or shellfish that may be equally affected by the site. This assumption of 

“resource switching” among local fish and shellfish is incorporated into the Framework by 

holding constant the total amount of fish and shellfish consumed. 

The policy decision to assume that resource switching occurs is supported by limited data 

and examples in Puget Sound. For example, individuals in the Suquamish Tribe (2000) study eat 

“more geoduck now, because they are more available to us, but we used to dry oysters and 

clams....” Two other respondents reported “reduced consumption of butter clams, cockles, and 

other clams and shellfish due to pollution,” but that this “reduced consumption was offset by the 

higher availability of geoducks from the Suquamish Tribe.” Resource switching has been 

documented in other areas affected by contamination, such as Alaska (Fall and Utermohle, 

1999). 

 The use of fisheries resources is important to Tribes for economic, dietary and cultural 

reasons. Tribes will likely use whatever fisheries resources are available to them. The following 

observation is made in the NEJAC report (EPA, 2002b): 

“For many communities of color, low-income communities, Tribes, and other indigenous 

peoples, there are no real alternatives to eating and using fish, aquatic plants, and wildlife. For 

members of these groups it is entirely impractical to “switch” to “substitutes” when the fish and 

other resources on which they rely have become contaminated. There are numerous and often 

insurmountable obstacles to seeking alternatives (e.g., fishing “elsewhere,” throwing back 

“undesirable” species of fish, adopting different preparation methods, or substituting beef, 

chicken or tofu). For some, not fishing and not eating fish are unimaginable for cultural, 

traditional, or religious reasons. For the fishing peoples of the Pacific Northwest, for example,

fish and fishing are necessary for survival as a people – they are vital as a matter of cultural 

flourishing and self-determination.” 
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D. Use of Anadromous Fish Data 

Salmon and other anadromous fish species are addressed separately from other species in 

this Framework. This distinction is based largely on differences in life cycles. [Note: 

steelhead, the anadromous strain of rainbow trout, are included with salmon in the Puget Sound 

Tribal studies.] 

Salmon

For sites in Region 10, particularly PCB-contaminated sediment sites, salmon have 

typically been excluded from the fish consumption rate used to estimate site-related risks. This 

exclusion has been based on the assumption that adult salmon spend most of their lives in the 

open ocean and take up bioaccumulative and persistent contaminants almost exclusively via the 

food chain in that environment. It also has been presumed that site-related chemicals are not 

transported to that relatively distant aquatic environment, where adult salmon might be exposed 

to them through the food chain. 

In this Framework, risks associated with the consumption of salmon may be eliminated 

from consideration as contributing to site-related risks, on a site-specific and chemical-specific 

basis. Factors that could be considered in decisions to include or exclude risks from persistent, 

bioaccumulative chemicals in salmon include salmon residence time near the site; evidence that 

salmon harvested near the site have higher concentrations of the contaminant of concern than 

salmon harvested in cleaner areas; and the relative likelihood that site-related contaminants are 

being transported to areas remote from the site, where salmon may accumulate them via the food 

chain. 

For site-related contaminants that are not considered bioaccumulative and persistent, the 

potential for salmon to take up such chemicals via epithelial tissue or gill contact while present in 

the vicinity of the site should generally be evaluated for inclusion in estimating site-related risks. 

Examples of other circumstances where it may be appropriate to exclude certain chemicals are 

provided in the Framework narrative and in the Flow Sheet. 

 Because information to fully evaluate these factors may be limited, decisions will, of 

necessity, be based on best professional judgment along with available, relevant scientific 

information. 

Other Anadromous Fish

Anadromous fish other than salmon (and steelhead trout) that have been harvested in 

Puget Sound may be consumed by Tribal members (Toy et al., 1996; Suquamish Tribe, 2000). 

Because these species may spend relatively more of their lives in the local aquatic environment 

than do salmon, and because the data generally are not available to determine whether or not 

contaminant body burdens may be locally acquired, it is recommended that non-salmon 

anadromous species that commonly occur at the site be included in the assessment of site-related 

risks. 
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E. Inclusion of Child-Specific Consumption Rates

The Framework recommends that child exposures to site-related contaminants due to fish 

and shellfish consumption be included in assessments of risks and development of media cleanup 

levels when the necessary data are available. Consistent with a 1997 Presidential Executive 

Order (The White House, 1997), EPA “shall ensure that its policies, programs, activities, and 

standards address disproportionate risks to children that result from environmental health risks.” 

The risk assessment results of EPA’s 1994-1996 Columbia River Basin fish contaminant survey 

demonstrated that, for Tribal members eating fish harvested from the Columbia River, noncancer 

health hazards to children were approximately twice those for adults (EPA, 2002d). 

The two studies that EPA used as sources for Tribal adult consumption rates also 

surveyed children’s fish and shellfish consumption. However, there are a number of issues that 

would need to be resolved before EPA would be prepared to include the Suquamish or Tulalip 

Tribes’ children’s consumption rate estimates into the Framework. EPA is planning to request 

the assistance of the Tribes and statisticians to address these issues and will expand this 

Framework to include child consumption information related to these Tribal studies as it 

becomes available. 

When adequate Tribal-specific studies for children’s consumption rates are unavailable, 

other options may be considered to estimate Tribal child fish and shellfish consumption rates in 

Puget Sound and the Strait of Georgia. Four are presented here without implying or 

recommending a preference. Other approaches also may be proposed for consideration. The 

decision as to how best to estimate child consumption rates should be considered on a sitespecific basis and in consultation with Tribes. 

 1) Fish and shellfish consumption rates are provided for age categories from ages 3 to 17 

in EPA, 2002a (Section 5.1.1.1, Table 5). The 99th percentile consumption rate of 100.5 g/day is 

identified for consumer and non-consumer children, ages 3 to 5, in the general U.S. population.5 

2) A ratio of adult to child consumption rates from another Tribal study could be applied 

to a Puget Sound Tribal- specific adult consumption rate to estimate a fish and shellfish 

consumption rate for children. For example, using data in the Columbia River Inter-Tribal Fish 

Commission (CRITFC, 1994) study, the median consumption rate for consumer-only children 

under six years of age can be calculated to be 40% of the median consumer-only adult 

consumption rate from the same study.6 This percentage could be applied to a Puget Sound 

5

 A higher consumption rate should be used for contaminants with reference doses based on developmental effects, 

when using this option. See Section VI.F. in this Framework. 

6

 Based on a comparison of the 50th percentile median consumer-only adult rate with the 65th percentile consumeronly child rate. Actual child fish consumption data were unavailable for the 50th percentile. 
12

Tribal-specific adult consumption rate to estimate a fish and shellfish consumption rate for 

children. 

3) The fish and shellfish consumption rate for children ages 3 to 5 is 38.9% of the adult 

rate, using a comparison of mean consumption rates for the general U.S. population from EPA, 

2002a (Section 5.1.1.1, Tables 4 and 5). This percentage could be applied to the adult rate used 

in a specific assessment to provide an estimate of children’s consumption rates. 

4) Total adult consumption rates (in units of grams per day) may be used in combination 

with children’s body weights to assess children’s. While this would likely result in an 

overestimation of children’s consumption rates, it would be inappropriate to attribute adult 

consumption rates in terms of grams per kilogram of body weight to children, since children 

generally consume more food per kilogram of body weight than do adults (EPA, 2000a; EPA, 

2002a). 

F. Other Exposure Considerations 

 An assessment of estimated risks associated with fish and shellfish consumption must 

include an assumption of the number of years Tribal members obtain fish from a specific 

harvesting area. Tribal-specific demographics that provide a high-end estimate of this exposure 

duration should be used if available. Otherwise, an assumption of 70 years, used as the standard 

default in Superfund and RCRA risk assessments to represent the lifetime of an individual, is 

recommended for use as the exposure duration when estimating Tribal risks from consuming fish 

and shellfish harvested in a given location. 

This Framework recommends that risk assessments be performed using the weight of 

uncooked fish, with no modification for potential contaminant losses or gains during cooking. 

The use of uncooked weights is consistent with the fact that uncooked fish consumption rates 

were measured in the Tribal fish and shellfish consumption studies cited in the Framework. 

Furthermore, results of fish tissue analyses in Region 10 are reported as contaminant 

concentrations in uncooked samples. 

Estimation of risks from eating fish and shellfish requires an assumption of the body 

weight of the consumer. This Framework recommends using the average body weight from the 

study selected for estimating the fish consumption rate. If body weights other than EPA’s default 

of 70 kg are used, EPA risk assessors may need to determine whether corrections to doseresponse relationships incorporated into risk calculations are necessary on a chemical-specific 

basis. 
13

IV. Steps for Selecting the Tribal Fish and Shellfish Consumption Rate 

The following sections are to be read in conjunction with the Flow Sheet provided with 

this Framework. Items in boldface type are quoted directly from the Flow Sheet. 

Application of this Framework requires many site-specific decisions and these decisions 

are expected to be made in consultation with the Tribe or Tribes interested in or affected by the 

site. These decisions and their supporting rationale should be documented in writing as part of 

EPA’s risk assessment and risk management processes. 

 Step 1: Select Basis for Tribal Fish and Shellfish Consumption Rate

The adjudicated U&A of the Tulalip Tribes extends from the Canadian border south 120 

miles to the northern end of Vashon Island, encompassing areas of both Puget Sound and the 

Strait of Georgia. The U&A of the Suquamish Tribe encompasses waters of Puget Sound and 

the Strait of Georgia from the northern tip of Vashon Island to the Fraser River in Canada, 

including Haro and Rosario Straits, the streams draining into the western side of Puget Sound, 

and Hood Canal. 

 Consumption rates were derived for this Framework from participants in the Suquamish 

Tribe and Tulalip Tribes studies (Suquamish Tribe, 2000; Toy et al., 1996) who reported 

consuming shellfish or specific categories of fish that were harvested from Puget Sound. 

Consumption rates of fish and shellfish harvested from Puget Sound were much higher for 

members of the Suquamish Tribe than for the Tulalip Tribes. A large percentage of this 

difference is shellfish consumption, particularly clams. A careful reading of the Suquamish 

Tribe (2000) study presents some of the cultural and historic basis for this difference. Extensive 

shellfish habitat is found in many areas of Puget Sound, including in the U&A of the Suquamish 

Tribe, but is uncommon in many other areas. 

As part of the Framework, Region 10 recommends, as a policy decision, that for 

CERCLA and RCRA sites in Puget Sound or the Strait of Georgia with extensive intertidal 

habitat, the consumption rate derived by EPA from data collected by the Suquamish Tribe 

represents a sustainable consumption rate suitable for estimating site-related risks. Again, as a 

policy decision, for sites in Puget Sound and the Strait of Georgia that lack extensive intertidal 

habitat, the consumption rate derived by EPA from data from the Tulalip Tribes represents a 

sustainable consumption rate. While less than for the Suquamish Tribe, significant quantities of 

shellfish are included in the total consumption rate of the Tulalip Tribes. Where a Tribal-specific 

survey exists, and where a cleanup site is within that Tribe’s exclusive U&A, the fish and 

shellfish consumption exposure scenarios also should include the consumption rate based on that 

Tribe’s data. 
14

 Box PS-1. Are Puget Sound fish and shellfish consumption studies relevant to the 

Tribe(s)? (“The Tribe(s)” refers to a Tribe or Tribes whose U&A is at or near the site.) 

 

 The Puget Sound Tribal fish and shellfish consumption data used in this Framework are 

for the Tulalip Tribes (Toy et. al., 1996) and the Suquamish Tribe (2000). If the answer is “no,” 

move to Box PS-3. If the answer is “yes,” move to Box PS-2. 

 Box PS-2. Does the site or its environs have (existing or potential) high quality 

physical habitat to support substantial shellfish harvest in the absence of contamination? 

 

If the answer is “yes,” move to Box PS-6, use the consumption rate derived from data 

collected by the Suquamish Tribe study as a basis for selecting the Tribal fish and shellfish 

consumption rate, and move to Box PS-8. If the answer is “no,” move to Box PS-5. The 

consumption rate derived by EPA from data from the Tulalip Tribes may be used as the basis for 

the Tribal fish and shellfish consumption rate. The answer might be “no” where, for example, 

some intertidal habitat exists, but does not include extensive shellfish beds. Move to Box PS-8. 

In addition, where a Tribal-specific survey exists and where a cleanup site is within the 

Tribe's exclusive U&A, the fish and shellfish consumption exposure scenarios should include the 

consumption rate based on that Tribe's survey data. Depending on the location of the cleanup 

site and other factors, this fish and shellfish consumption rate may not be the only consumption 

rate evaluated. 

 The following information is provided to support the assessment of shellfish habitat 

quality. The assessment can be done by assembling existing information for the categories given 

below, discussing how the parameters affect physical habitat quality, and using the results of the 

assessment to help make the Yes/No determination for Box PS-2. Because information to fully 

evaluate these factors may be limited, decisions will, of necessity, be based on best professional 

judgment along with the available relevant scientific information, as well as oral history or other 

information a Tribe would like to contribute to the evaluation. This evaluation is expected to be 

performed in consultation with the Tribe or Tribes interested in or affected by the site.

 Given the wide variety of feeding, growth, and survival strategies of shellfish, high 

quality and quantity of shellfish harvest relies on many interacting parameters. Assessing the 

available information for the following can help determine whether high quality physical habitat 

exists (or could exist) at the site or its environs, regardless of the presence or absence of siterelated contaminants:

• Basic characteristics 

Food availability – are levels of food in the water column or sediment sufficient to support high 

shellfish growth rates? If not, then even optimal physical substrate, temperatures, absence of 

predators or other factors important to survival and growth will not be good indicators of high 

harvest potential. 
15

Water quality – are the basic water quality parameters (not related to site releases) in optimal 

ranges for shellfish growth? This determination will likely be species-specific. 

Substrate quality – are the basic sediment parameters (not related to site releases of 

contaminants) in optimal ranges for shellfish growth? This determination will be species-specific 

since different habitats (mudflat, sand, hard substrates, dredged channels, etc., will support 

different species with different productivities). A second, important aspect of substrate physical 

quality to assess is harvestability, i.e., does the physical habitat such as debris or soft mud affect 

access to the shellfish? 

• Existing shellfish quality/quantity 

The shellfish may or may not be a useful indicator of high quality physical habitat. Sampling 

shellfish to evaluate condition, growth rates, survivorship, and reproduction can provide 

information that integrates multiple parameters influencing shellfish productivity. If existing 

shellfish populations are high in quality (e.g., tissue mass per individual) and quantity (e.g., 

density), then it is reasonable to conclude the physical habitat is of high quality. However, if 

existing shellfish populations are absent or low in quality, then the assessment of high quality 

physical habitat will rely on the evaluation of food availability and water and sediment quality as 

outlined above. 

• Site context

Site context is an important element in the assessment of high quality habitat that will support 

substantial shellfish harvest in the absence of contamination. It may be useful to consider the 

quantity of high quality shellfish habitat within a reasonable geographic area (river, bay, etc.) at 

or around the site. Areal estimates of existing or potential habitat could be described for the 

intertidal, shallow subtidal, and deeper subtidal areas. For example, in an urban river estuary, 

total intertidal area might be estimated as approximately 500 acres, whereas high quality 

intertidal shellfish habitat is approximately 20 acres, whereas a large bay might have 10,000 

acres of shallow subtidal habitat with 9,000 estimated as high quality. 

• Other considerations

Additional parameters may affect the overall assessment of high quality physical habitat (e.g., 

disease, predation, competition, settlement cues, etc.). 

• Existing v. potential quality

It is important in the assessment to evaluate existing conditions and also consider whether future 

likely conditions could change the physical habitat quality/quantity. 

Table 1 describes specific examples of the above-defined parameters that may be evaluated on a 

site-specific basis to provide input to the assessment of high quality physical habitat for shellfish 

harvest. Characterizing habitat quality will ultimately depend on the species of shellfish 

evaluated and their tolerances for existing and potential habitat parameters. Habitat quality 

should be evaluated for a variety of shellfish. For example, for bivalves, several example species 
16

of both surface deposit feeders and suspension feeders (e.g., mussels, geoducks, soft-shell clams, 

horse clams, cockles, etc.) selected on the basis of their ecological and human health importance 

(e.g., Tribal preferences) should be included in the assessment. The habitat characteristics, both 

existing and potential (i.e., in the absence of site-related and non-site-related contamination) at a 

site may then be compared with the shellfish habitat requirements. 

Table 1. Characteristics for evaluating high quality shellfish habitat to support 

substantial shellfish harvest and examples of types of parameters that can be 

evaluated for both existing and future conditions 

Basic Characteristics – not related to site releases of contaminants 

Food (water column and 

sediment) 

Chlorophyll a, Total Suspended Solids, nutrients (NO3, 

NH4) 

Source of food (stable isotope ratios) 

Water Quality Temperature range, dissolved oxygen, salinity range, 

pH, turbidity 

Sediment Quality Temperature range, dissolved oxygen, salinity range 

(including ground water discharges such as seeps), tidal 

range, organic carbon, grain size distribution (surface 

and at depth) 

Access to harvest (debris, shore/water access, substrate) 

Existing Shellfish Quality/Quantity 

Quality Condition index, scope for growth, survivorship, 

reproduction, growth rate (mm/month, growth rings, 

etc.), adult size 

Quantity Density (#/m2), recruitment, survivorship 

Site Context 

Context of the amount of 

high quality habitat 

For example, estimate both total intertidal area and the 

high quality intertidal area in a reasonable geographic 

area (river, bay, etc.) at or around the site. Estimates can 

be made for shallow subtidal and deeper subtidal areas. 

Other Considerations 

Larval pool and settlement 

cues 

Recruitment 

Predation Density, shell indicators (breaks, drill holes, etc.), 

refugia (substrate, debris, plants, etc.) 

Background levels of nonsite-related contaminants Tissue residues, sediment or water concentrations, 

fecal coliforms, PSP, Domoic acid, etc. 

Competition Density and growth rates 

Disease Shellfish pathology 
17

Box PS-3. Will there be (or has there been) a fish and shellfish consumption study 

conducted for the potentially affected Tribes? A study of this nature would be preferred if the 

Tribal data used in this Framework are inappropriate. However, because of time, cost, and 

information constraints, the preparation of site- and Tribe-specific fish and shellfish consumption 

studies is likely to be the exception, not the rule. In addition, artificially suppressed consumption 

rates may be present if the local aquatic environment has been significantly impaired by 

contamination. In such cases, use of a surrogate study may be preferable. If the answer is 

“yes,” move to Box PS-4. If the answer is “no,” move to Box PS-7. 

Box PS-4. The Tribal-specific consumption study may be used as the basis for fish 

and shellfish consumption rates.

Box PS-7. The default consumption rate of 215.7 g/day (EPA, 2002a) may be used 

when no Tribal-specific value is available or appropriate. This is the least preferred option, 

consistent with the hierarchy in the AWQC Methodology (EPA, 2000a). Move to Box PS-8. 

 Box PS-8. Proceed to Step 2 of the Flow Sheet to select the consumption rate. 

 Step 2: Select Fish and Shellfish Consumption Rate

The Puget Sound Tribal fish consumption studies cited in this Framework include 

information on all fish and shellfish consumed by the surveyed Tribal members, including, for 

example, fish and shellfish purchased in stores or restaurants, some of which may have come 

from other water bodies. The studies may also reflect fish and shellfish harvested by Tribal 

members far from the cleanup site. To assume that the total quantity of fish and shellfish 

consumed by the participants in the studies was harvested from the local aquatic environment 

would likely result in a significant overestimate of risks and hazards due to site-impacted fish 

and shellfish. To estimate the portion of consumption rates that may be impacted by site 

releases, the Framework includes consumption rates only for fish and shellfish identified by 

individual survey participants as having been harvested from Puget Sound. All fish and shellfish 

identified as being obtained from grocery stores, restaurants, or locations outside Puget Sound 

were eliminated from the consumption rates presented herein for use in estimating risks and 

developing cleanup levels. (See Appendix C for further details on the method for calculating the 

rates in Box PS-9.) 

Box PS-9. Select the fish and shellfish consumption rates corresponding to the 

information source selected in Step 1. 

Box PS-9 lists the 95th percentile consumer-only consumption rates of fish and shellfish 

harvested from Puget Sound derived from the data collected by the two Puget Sound Tribes. 

Also listed is the default value recommended when appropriate Tribal-specific data are not 

available. 
18

Box PS-10. Select a mix of categories or species of fish and shellfish to reasonably 

represent consumption patterns, while holding constant the total consumption rate. This 

task is not necessary where only a total consumption rate is needed, regardless of species. Most 

of the data in the Puget Sound Tribal seafood consumption studies are available by fish types 

(bottom, pelagic, anadromous, and shellfish). (See Appendix B.) 

• If a Tribe-specific consumption study is available and applicable to the site in question, 

calculate the ratio of fish types or species from average consumption rates, and apply 

those ratios to the 95th percentile consumption rate. 

• Where the consumption rate is based on the Tulalip or Suquamish Tribal survey results, 

the ratios of fish types provided in Appendix B of this Framework should generally be 

used. Where necessary, these values may serve as a starting point for further decisions, 

for instance, the percentages of shellfish consumed represented by crab and by clams. If 

the values in Appendix B are not appropriate to a particular site, consideration should be 

given to adjusting these rates, based on information about the types and abundance of fish 

and shellfish present at the site and/or information provided by the affected Tribes about 

preferred catch. 

 

• For sites where the general U.S. population per capita consumption rate (EPA, 2002a) is 

used, apply either ratios based on one of the two Puget Sound Tribal studies (if 

considered appropriate to the local aquatic environment) or develop ratios relevant to the 

affected Tribe(s). In general, the ratios reported in EPA (2002a) are unlikely to be 

relevant, because they are based on the types of fish available and consumed throughout 

the country. 

Other assumptions about the mix of species that constitutes the Tribal fish and shellfish 

diet may be used for additional risk calculations. Such analyses might focus on species or groups 

of species (e.g., those with relatively small home ranges) thought to present the largest source of 

risk to Tribal members. In addition to potentially affecting remedy selection, this type of analysis 

can help characterize the uncertainty or sensitivity of the calculated risks to assumptions about 

species ratios within the diet. 

Box PS-11 and Box PS-12 reflect possible species-specific or contaminant-specific 

modifications. A hypothetical case applying the information in Boxes PS-11 and PS-12 is 

provided in Appendix D. 

 Box PS-11. Salmon. 

A decision must be made to include or exclude risks associated with consumption of 

salmon on a site-specific and contaminant-specific basis. See Section III.D for examples of 

factors to consider when making this decision, Section V for associated uncertainties, and Box 

PS-12 for other considerations. 
 Box PS-12. Additional contaminant and aquatic life issues. 

This step may be used in consultation with a fish biologist or other expert to 

determine whether it is appropriate to reduce estimates of site-related risks due to 

consumption of fish. A contaminant may be eliminated from consideration for certain 

species or groups of species if sufficient evidence demonstrates that it does not 

accumulate or is not otherwise present in the tissue when harvested; that it is present but 

from a source other than the cleanup site; or that it is present but not of concern to human 

health. Examples of such evidence may include but are not limited to the following: 

• Residence time in the vicinity of the site precluding more than de minimis uptake 

of the contaminant into tissue of the fish type being evaluated 

• Adequate sampling/chemical analysis demonstrating that a contaminant is absent 

from tissue, using analytical methods sufficiently capable of detecting 

concentrations of concern to the maximum degree practicable 

• Scientific literature providing significant evidence that the contaminant as found 

in fish is not of concern for human health 

• Modeling of the contaminant demonstrating no significant bio-concentration or 

bioaccumulation in tissue of the relevant category or species of fish, regardless of 

residence time in the local aquatic environment 

• Metabolism in the organism rendering the contaminant of no concern to human 

health upon consumption of the fish 

• Kow/water solubility characteristics substantially limiting uptake of the 

contaminant into tissue of the fish. 

For discussions of some of these issues, see Barnhard (2003), Roose and 

Blindman (2000) and Hall (2002). 

V. Selection of Species for Collection of Chemical Contaminant Data and 

Derivation of Exposure Point Concentrations 

 A. Selection of species for collection of chemical contaminant data 

 In preparing to collect contaminant data for aquatic biota that may be affected by 

site- specific contamination, considerations in determining which species should be 

analyzed for contaminants should include: 

• Which species are most commonly consumed by Tribal members; 

Page 19 
• Which species may have the highest levels of contamination (e.g., predators, bottom 

feeding species); 

• Area fidelity of species: species that tend to stay in a specific area are more likely to 

be impacted by site-related contaminants than are species with large home ranges; 

• Relative abundance of a species; and 

• Which species may have the highest lipid content; species with higher fat-containing 

tissue are likely to have higher wet weight contaminant concentrations of lipophilic 

contaminants. 

. 

B. Derivation of exposure point concentrations when data for multiple 

species are available. 

 

 When chemical contaminant concentrations are available for multiple species 

within a species group (i.e., benthic, pelagic, shellfish, anadromous. etc.), the question 

arises as to how to utilize these data to derive an overall species group contaminant 

concentration for computation of total contaminant dose and consequent risks. There are 

a number of ways by which this issue could be addressed. The site-specific approach is 

expected to be selected in consultation with the Tribe or Tribes interested in or affected 

by the site. Approaches may include: 

1. Weighting contribution of individual species contaminant concentrations on 

the basis of species-specific consumption rates from seafood consumption 

surveys. 

 

When species-specific consumption rates and contaminant concentrations are 

available, those consumption rates may be used to develop a weighted 

contaminant concentration for that species group. Average consumption rates are 

based on consumption of a species regardless of source (e.g. harvested, purchased 

in grocery stores, consumed in restaurants) and would be obtained from either 

published study results or by analyzing the data associated with a study. The 

equation for computing a weighted species group concentration is as follows: 

Cweighted = C1 x (IR1 / Σ IR) + C2 x (IR2 / Σ IR) + ... + Cn x (IRn/ Σ IR) 

Where: 

Cweighted = the weighted contaminant concentration for the species group 

C1, C2,...Cn = 95% upper confidence level (UCL) on the mean contaminant 

concentrations for individual species within the species group (an estimate of the true 

average concentration); 

IR1, IR2,...IRn = average ingestion rates for individual species within the species group 

regardless of fish and shellfish source; and 

Page 20 
ΣIR = the sum of the average ingestion rates for all species for which chemical 

contaminant data are available 

 In some instances, there may be data on a species that is representative of more 

than one species within a species group. This is particularly likely for shellfish. For 

example, concentration data for a single species of clam may be used to represent 

contaminant concentrations in all bivalves; concentration data from a single species of 

crab may be used to represent contaminant concentrations in all crabs. In cases where a 

species may be representative of multiple species within a species group, the combined 

ingestion rate for these multiple species should be used to develop the weighted 

concentration rather than the consumption rate of the individual species. For example, if 

data were available for a bivalve species and a crab species, the weighted concentration 

would be computed using: the 95% UCL species-specific bivalve contaminant 

concentration, the average consumption rate for all bivalves, the 95% UCL speciesspecific crab contaminant concentration, and the average consumption rate of all crab 

species. 

2. Weighting contaminant concentrations based on best professional judgment. 

Such weighting factors may include the following considerations:

• Average 95% UCLs for all species: 

The average of the 95% UCL concentrations for all species could be used for the 

species group concentration. 

• Use of the highest concentration: 

The entire species group concentration could be based on the highest 95% UCL 

concentration obtained for an individual species. 

• Development of weighting factors based on the relative biomass of the different 

species: 

This approach assumes that consumption is directly proportional to the 

availability of different species. 

 It may be helpful to employ several of these approaches to characterize the 

uncertainty contributed by a lack of knowledge of the consumption rates for different 

species within a species group. The site-specific approach is expected to be selected in 

consultation with the Tribe or Tribes interested in or affected by the site. 

Page 21 
VI. Uncertainties

To promote transparency, EPA risk characterizations associated with risk 

assessment and the derivation of cleanup levels should include a statement of relative 

confidence and protectiveness. All major uncertainties should be identified, along with 

commentary regarding their influence on the assessment, consistent with agency 

guidance (EPA, 1989, 2000d). All uncertainties inherent in this Framework, as presented 

below, should also be described. The degree to which this Framework provides a 

protective estimate of exposure to contamination from consumption of fish will depend 

upon the choices made in its implementation.

A. Use of a Tribal-specific fish and shellfish consumption study as a 

surrogate for another Tribe’s consumption rate

The use of consumption rates of Puget Sound-harvested fish and shellfish derived 

using Tulalip and Suquamish Tribal data as a surrogate for another Tribe in Puget Sound 

or the Strait of Georgia could lead to either an overestimate or an underestimate of the 

actual fish and shellfish consumption rate potentially associated with site releases. For 

many reasons (e.g. cultural practices, treaty rights, types and quantities of seafood species 

available), Tribes surveyed in local fish and shellfish consumption studies may eat 

different quantities and ratios of fish and shellfish than do those who harvest near a 

cleanup site. Habitat quality and thus the quantity of fish and shellfish available for 

sustainable harvest may also be different. If the surrogate study is based on fish and 

shellfish habitat of higher quality and greater sustainable harvest capacity than would 

ever be possible for the water body under evaluation, use of the surrogate data could lead 

to an overestimate of risks at the site. There is also the possibility that the Tribe affected 

by site-related releases may have higher quality resources than the study Tribe, in which 

case consumption rates may be underestimated. The development of additional 

appropriately designed and conducted Tribal consumption studies in Puget Sound and in 

the Strait of Georgia would contribute to the reduction of these uncertainties. 

B. Degree to which traditional lifeways or subsistence fish and shellfish 

consumers are included in existing Tribal consumption studies 

The studies for the Suquamish and Tulalip Tribes did not attempt to quantify or 

otherwise distinguish fish and shellfish consumption for Tribal members who consider 

themselves to be subsistence consumers or who practice traditional lifeways, although 

fish and shellfish consumption rates for some individuals who fall into these categories 

are almost certainly included in the studies. Without a Tribal-specific definition of 

subsistence fish and shellfish consumption and without data on the subsistence use of 

areas affected by the cleanup site, it is difficult to determine the degree to which 

subsistence consumers are protected by the consumption rates recommended in this 

Framework. 

Page 22 
C. Percentage of consumed fish and shellfish assumed to be adversely 

affected by site-related contamination 

For purposes of this Framework, consumption rates for fish and shellfish 

harvested only from Puget Sound were derived from the Tulalip and Suquamish Tribal 

data, for use in determining the amounts of consumed fish and shellfish that may be 

impacted by a cleanup site located in Puget Sound. This Framework also recommends 

the use of these studies to derive consumption rates for a Tribe potentially affected by 

cleanup sites in the Strait of Georgia, on a site-specific basis. The quantities of fish and 

shellfish identified in the surveys as having been obtained in restaurants or grocery stores 

or harvested from areas outside Puget Sound were excluded from the consumption rates, 

for purposes of estimating risks that could be associated with site releases. If none of the 

Tribal study consumption rates is determined to be appropriate for a particular cleanup 

site or Tribe, and the default consumption rate is used, no downward adjustment of the 

total fish and shellfish consumption rate is recommended in this Framework. 

Although the degree to which site-related risks could be overestimated by the use 

of any of the fish and shellfish consumption rates presented in this Framework cannot be 

known precisely, these methods are preferable to alternatives that would be likely to 

underestimate site-related risks, such as basing a consumption rate (or site-related 

estimates of risk) on the size of the cleanup site, or reducing the site’s estimated 

contribution to fish and shellfish contamination because nearby sites or sources are 

associated with similar contaminants. This Framework includes the assumption that the 

selected Tribal fish and shellfish consumption rates and their associated risk estimates 

will not be reduced based on consideration of the size of the cleanup site or the presence 

of additional sources of contamination. 

The use of a consumption rate based on all fish and shellfish harvested from Puget 

Sound as a surrogate for a consumption rate based on fish and shellfish affected by a 

cleanup site is likely to overestimate the risk of eating fish and shellfish from the site, 

since only a portion of the fish and shellfish diet will have actually come from the site in 

question. The degree of overestimation depends upon such factors as size and location of 

the site, type and degree of contamination, and habits of affected fish and shellfish. On 

the other hand, some of the fish and shellfish consumed in restaurants or obtained in 

grocery stores may have been harvested in Puget Sound, which could lead to an 

underestimate of exposure. 

D. Exclusion or inclusion of risks associated with salmon consumption on 

contaminant-specific basis 

This Framework allows exclusion of risks associated with salmon consumption if 

warranted by site-specific and chemical-specific circumstances, particularly for persistent 

and bio-accumulative contaminants. Some of the uncertainties in this exclusion arise 

from the degree of historical contaminant transport offsite and from salmon residence 

time near the site. 

Page 23 
PCBs and other bio-accumulative and persistent chemicals found in contaminated 

sediments can be moved from their site of release via erosion, dredging, tidal currents, 

flood events, and vapor transport. Offsite transport is also possible when aquatic 

organisms become contaminated near a cleanup site and then migrate to distant locations, 

where they contribute to food chain effects that eventually affect fish, including adult 

salmon. However, adult salmon body burdens of bio-accumulative and persistent 

contaminants typically come from many sources and cannot currently be apportioned 

with confidence to specific locations. An assumption that contaminants present in 

harvested salmon are not associated with the site, even when the same chemicals have 

been released from the site, is likely to underestimate the site’s contribution to risks from 

consuming such fish. The degree of underestimation is not known. 

If the full body burden of bio-accumulative and persistent contaminants released 

at a site and found in local salmon is attributed to a single source (i.e., the site under 

evaluation), site contributions to risk are likely to be overestimated, since some portion of 

the body burden likely has been acquired elsewhere. 

Some site-related contaminants may bio-concentrate in adult salmon due to 

epithelial tissue or gill contact, depending in part upon the salmon residence time in the 

vicinity of the site-related contamination. Making an assumption that adult salmon do 

not reside in the vicinity of the site long enough for bio-concentration to occur could 

result in an erroneous exclusion of contaminants in salmon from the site-related risk 

assessment. An assumption that bio-concentration does occur could lead to an 

overestimation of risks if uptake does not occur. 

E. Use of the National Fish and Shellfish Consumption Rate to Characterize 

Tribal Consumption

The fish and shellfish consumption rate of 215.7 g/day from Estimated Per Capita 

Fish Consumption in the United States (EPA, 2002a) is a high-end (99th percentile) 

estimate of total fish and shellfish consumption for the general U.S. population, including 

both people who consume fish and shellfish and those who do not. It is identified as an 

appropriate value to represent an average subsistence consumption rate (EPA, 2000b). Its 

use is recommended in this Framework as a default Tribal consumption estimate when 

relevant Tribal-specific studies are not available. 

EPA’s preference and general practice is to use the 95th percentile consumption rate 

for purposes of estimating risks to a given population, when that information is available 

(EPA, 1989). Use of the default consumption rate of 215.7 g/day may either over- or 

underestimate the actual 95th percentile consumption rate of fish and shellfish of the Tribal 

population being evaluated. Using consumer-only consumption rates would be expected to 

overestimate the consumption rate of the general population, but it may not result in 

overestimates for populations that consume seafood on virtually a daily basis. 

Page 24 
F. Special Considerations of Vulnerable Individuals and Exposures to Chemicals 

with Selective Endpoint 

Many of EPA's risk assessments and cleanup levels for the protection of human health 

are based on estimated carcinogenic and noncancer adverse effects. Not all effects can be 

quantified, due to scientific limitations concerning dose-response effects, exposures to 

multiple chemicals, and factors such as individual variability. As a result, for example, for 

contaminants such as methyl mercury that have reference doses based on developmental 

effects, EPA’s AWQC methodology (EPA 2000a) recommends that higher fish consumption 

rates be assumed for children and for women of child-bearing age, when using fish and 

shellfish consumption rates that are based on consumers and non-consumers, such as the 

default recommended in this Framework. (See Sections III.A and III.E of this Framework for 

discussions of default rates.) Under these circumstances, the AWQC methodology 

recommends that consumption rates be based on data for consumers only7, as differentiated 

from the AWQC recommendation to use consumption rates based on both consumers and 

nonconsumers for other population groups (EPA, 1998b; 2000a). This is an acknowledgment 

of the potentially increased sensitivity of certain segments of the general population to 

chemical-specific effects. 

 

 Chemicals that cause human developmental, neurotoxic, endocrine-disruption or other 

adverse effects at potentially lower concentration than reflected by reference doses or other 

indicators of safe exposure levels, may affect individuals within a population differently. 

Within a Tribal community, individuals who may have increased vulnerabilities to potentially 

toxic chemicals include “elders, pregnant women, young children, persons who are ill, and 

individuals who have compromised immune systems or limited liver and kidney function” 

(Arquette et al., 2002). 

 

Decision documents for risk assessment and cleanup level development should include 

discussions of uncertainties in risk characterization associated with fish and shellfish 

consumption. Where appropriate, such discussions should include potential site-related risks 

that are not quantifiable, such as for health effects not addressed by chemical-specific 

reference doses or cancer potency factors, and the presence of exposed individuals within a 

population who may be more susceptible than those for whom risks are quantitatively 

estimated. For site-related contaminants in fish and shellfish that have reference doses based 

on developmental effects, or for early-life exposure to carcinogens, current EPA guidance on 

the assessment of risk and associated uncertainty should be consulted. 

G. Use of Uncooked Fish and Shellfish Rates as Representative of Weight of Fish 

and Shellfish Consumed 

Because of the many ways in which fish may be served, quantitative assumptions 

regarding preparation methods and their effects on contaminant concentrations would be 

unreliable. Depending upon the preparation and cooking procedures, and upon the nature of 

7

 See Section 5.2.1.1 Tables 3 and 5 in EPA, 2002a. 

Page 25 
the contaminants in the fish, concentrations may decrease or increase (EPA, 1998a). For fatsoluble compounds such as PCBs, trimming and removing adipose tissue reduces the mass of 

contaminants in the consumed portion of the fish. Similarly, broiling, frying, or grilling fish is 

likely to result in reductions of fat-soluble compounds (Sherer and Price, 1993). Cooking is 

not likely to change the level of exposure to mercury because it is bound to muscle tissue and 

is not lost by cooking, which mostly removes moisture and fat (Morgan et al., 1997). Fish 

cooked with no prior preparation, as in a stew, might show negligible loss of contaminants, 

except perhaps for volatile contaminants. Because lead concentrates in bones, preparations 

where bones are discarded are likely to result in reductions in lead exposure (Ay et al., 1999). 

H. Use of An Exposure Duration of 70 Years 

A 70-year exposure period, that is, the number of years a Tribal member is expected to 

consume fish and shellfish from a specific harvesting area, is encouraged in this Framework 

where Tribal specific demographic data are not available. Risks and hazards will be 

overestimated for Tribal members who obtain fish and shellfish from the harvest area for 

fewer than 70 years, but underestimated for those exposed for more than 70 years. 

Uncertainties associated with such surrogate values should be discussed in the risk 

characterization document, including any assumptions made regarding future exposure 

durations. 

 I. Assumption that Resource Switching Occurs

If certain types of fish or shellfish preferred by Tribal members are not present in their 

U&A, this Framework assumes that Tribal members will substitute alternative local types of 

fish or shellfish in their diets, generally within the same category of fish or shellfish. Thus, the 

total consumption rate remains the same, regardless of the availability of a particular type of 

fish or shellfish. This is a reasonable and protective assumption for Tribal members who, for 

economic, ceremonial, religious, or personal preference reasons, are likely to substitute one 

species for another. The assumption that resources will be switched is likely to result in an 

overestimate of risks for other Tribal members who may decrease their overall fish and 

shellfish consumption rate because their preferred types are unavailable. Risks may be 

underestimated if the actual dietary practices of a Tribe would result in consumption of 

species that have higher contaminant levels than the preferred or assumed types of fish or 

shellfish. 

 J. Exposure to Contaminants in Fish and Shellfish Other Than by Consumption

To the extent that Tribal members are exposed by methods other than consumption 

and these exposure pathways can be identified, such exposure should be incorporated into a 

risk assessment, even if only qualitatively. Examples are use of bones as whistles and use of 

fish fat as a basis for skin paints. Omission of these potential exposures may underestimate 

risks and hazards, but to an unknown degree. 

Page 26 
 K. Potential Overestimation of Bottom and Pelagic Fish Consumption in the 

Suquamish Study

Some of the bottom and pelagic fish included in the Suquamish study as being 

harvested from Puget Sound were harvested in the Strait of Juan de Fuca. Assuming that these 

fish are harvested in Puget Sound, and including them in the Framework, may overestimate 

hazards and risks due to site-related contamination, although the degree of such 

overestimation is unknown. 

 L. Uncertainty in Developing Weighted Species Group Concentrations in 

Situations Where Data on Multiple Species are Available

Weighted species group contaminant concentrations (Section V) may be overestimated 

if the EPA derived consumption rates for species with higher contaminant concentrations are 

greater for the Suquamish or Tulalip Tribes than the consumption rate for these species for the 

Tribe or Tribes affected by a site. Conversely, species group contaminant concentrations may 

be underestimated if the consumption rates for species with higher contaminant concentrations 

are greater for the affected Tribe or Tribes than for the EPA derived consumption rate for the 

Suquamish or Tulalip Tribes. 

VII. Risk Communication and Risk Management Issues

 The following risk communication and risk management ideas may be useful for 

project managers to consider when implementing this Framework at RCRA and CERCLA 

cleanup sites. 

 As much as possible, the risk assessment should include a description of consumption 

rates in terms that are meaningful to the intended audience (e.g., number of 8-oz meals per 

week, number of pounds per week). A consumption rate of 32.4 g/day is equivalent to onehalf pound of fish and shellfish per week; 143 g/day is equivalent to 4.4 – one-half pound 

meals of fish and shellfish per week or an average of 2.2 lbs per week. The terms to describe 

consumption rates should be decided on a case-by-case basis. 

 Once it is determined that action is necessary to protect human health, site managers 

should consider including at least one remedial alternative that could reduce the excess cancer 

risk to the most protective end of EPA’s acceptable risk range, using exposure rates selected 

under this Framework. Even if not practicable to implement, such an alternative would 

provide a point of comparison for risk management decisions. 

 The effect of the assumptions on the potential for over- or underestimating risk is an 

important aspect of EPA’s risk management and cleanup decisions. All discussions and 

presentations about risk should clearly describe assumptions and uncertainties in the 

characterization of risk. One format that may be useful for EPA’s risk management 

Page 27 
discussions is the table presented in Part A, Exhibit 6-21 of EPA’s (1989) risk assessment 

guidance for Superfund. This table lists each assumption or factor producing the uncertainty 

and its potential to over- or underestimate exposure.

VIII. Five-Year Review Considerations 

Based on EPA’s knowledge of sediment clean-up sites in Puget Sound, the 

Framework may have limited application for those CERCLA and RCRA sites where the 

remedy has already been selected. 

After a remedy has been selected, CERCLA requires that five-year reviews be 

conducted at any remedial action site that does not allow for unlimited use or unrestricted 

exposure. The purpose of the five-year review is to assure that human health and the 

environment will be protected by the remedial action. 

As part of the five-year review process, Tribes can provide new information to be 

considered or request that the lead federal agency evaluate particular aspects of a remedy 

relative to Tribal interests. Such requests are most helpful when provided to the lead 

federal agency early in the five-year review process. Such requests would be evaluated 

on a site-specific basis and consistent with EPA’s five-year review guidance. EPA would 

generally discuss the appropriate means for addressing a Tribe’s concern with the Tribe 

during the review process. 

While a CERCLA five-year review includes considering new information, such as 

new information regarding exposure rates and assumptions, it is important to keep in 

mind that remedies and cleanup levels at CERCLA sites are determined by many factors. 

In determining whether a recalculation of site risks or any other detailed analysis is 

needed as part of the five-year review, EPA would review the basis of the selection of the 

remedial action and cleanup levels and other relevant information to determine whether 

further analysis of such updated information is appropriate, and focus our analysis on 

matters that would help assess the protectiveness of the selected remedy. 

It is important to note that even when a five-year review recommends that a 

remedy change be considered, such a change would happen through a CERCLA decision 

process. This process would require a ROD Amendment or Explanation of Significant 

Differences, not just a five-year review report, and would include consideration of the 

NCP’s nine criteria. Such changes would include consultation with the affected Tribes 

and would be subject to appropriate public review. 

The RCRA program does not have an equivalent five-year review process. For 

RCRA corrective actions being conducted as part of an operating or post-closure permit, 

a new permit must be applied for prior to expiration of the current permit (typically every 

10 years). The selected clean-up standards and selected remedy would be reviewed 

during the permit renewal to assure that the new permit is based upon currently 

applicable standards and regulations. 

Page 28 
EPA acknowledges that a Tribe’s interest in or need for public health related 

information, such as data about existing or residual health risks to Tribal populations, 

may be better served outside the five-year review. EPA is available to work with Tribes 

interested in this type of information. 

 

Page 29 
IX. References

Arquette, M., M. Cole, K. Cook, B. LaFrance, M. Peters, J. Ransom, E. Sargent, V. Smoke 

and A. Stairs. 2002. Holistic Risk-Based Environmental Decision Making: A Native 

Perspective. Environmental Health Perspectives Supplements, 110(S2). April. 

Ay, O., M. Kalay, L. Tamer and M. Canli. 1999. Copper and lead accumulation in tissues of a 

freshwater fish Tilapia zillii and its effects on the branchial Na, K-ATPase activity. 

Bulletin of Environmental Contamination & Toxicology, 62: 160-168. 

Barnhard, Lawrence P. 2003. Factors influencing the design of bioaccumulation factor and 

biota-sediment accumulation factor field studies. Environmental Toxicology and 

Chemistry 22(2): 351-360. 

CRITFC (Columbia River Inter-Tribal Fish Commission). 1994. A Fish Consumption 

Survey of the Umatilla, Nez Perce, Yakama and Warm Springs Tribes of the Columbia 

River Basin. CRITFC Technical Report No. 94-3. Portland, Oregon. 

EPA. 1989. Risk Assessment Guidance for Superfund. Volume I: Human Health Evaluation 

Manual (Part A). EPA/540/1-89/002. December. 

http://www.epa.gov/superfund/programs/risk/ragsa/ 

EPA. 1998a. Methodology for Assessing Health Risks Associated with Multiple Pathways of 

Exposure to Combustor Emissions. Chapter 8. EPA 600/R-98/137. 

EPA. 1998b. Ambient Water Quality Criteria Derivation Methodology Human Health 

Technical Support Document. Final Draft. EPA/822/B-98/005. July. 

http://www.epa.gov/waterscience/humanhealth/awqc-tsd.pdf

EPA. 1998c. Guidance for Conducting Fish and Wildlife Consumption Surveys. 

EPA-823-B-98-007. November. 

EPA. 2000a. Methodology for Deriving Ambient Water Quality Criteria for the Protection of 

Human Health (2000). Office of Water. EPA-822-B-00-004. 

http://www.epa.gov/waterscience/humanhealth/method

EPA. 2000b. Revisions to the Methodology for Deriving Ambient Water Quality Criteria for 

the Protection of Human Health (2000); Notice. 65 Fed.Reg. 66,444. November 3. 

http://www.epa.gov/fedrgstr/EPA-WATER/2000/November/Day-03/w27924.htm

EPA. 2000c. Guidance for Assessing Chemical Contaminant Data for Use In Fish Advisories. 

Volume 2: Risk Assessment and Fish Consumption Limits - Third Edition. 

http://www.epa.gov/ost/fishadvice/volume2/index.html 

Page 30 
EPA. 2000d. Risk Characterization Handbook. Science Policy Council. EPA 100-B-00-002. 

December. 

http://www.epa.gov/OSP/spc/rchandbk.pdf 

EPA. 2001. U.S. Environmental Protection Agency - Region 10 - Tribal Consultation 

Framework. 

http://yosemite.epa.gov/r10/Tribal.NSF/0/4e239b01fbabd5198825694b00041cc5?OpenDo

cument

EPA. 2002a. Estimated Per Capita Fish Consumption in the United States EPA-821-C-02-

003. August 2002. 

http://www.epa.gov/waterscience/fish/consumption_report.pdf

EPA. 2002b. Fish Consumption and Environmental Justice. National Environmental Justice 

Advisory Council. November. 

http://www.epa.gov/compliance/resources/publications/ej/fish_consump_report_1102.pdf

EPA. 2002c. Guidelines for Ensuring and Maximizing the Quality, Objectivity, Utility, and 

Integrity of Information Disseminated by the Environmental Protection Agency 

(Information Quality Guidelines). EPA/260R-02-008. October. 

http://www.epa.gov/oei/qualityguidelines/EPA_OEI_IQG_FINAL_10-2002.pdf

EPA, 2002d. Columbia River Basin Fish Contaminant Survey. EPA 910-R-02-006. August. 

http://yosemite.epa.gov/R10/OEA.NSF/Reports/Reports

Fall, James A., and C.J. Utermohle, compilers. 1999. Subsistence Service Update: 

Subsistence Harvests and Uses in Eight Communities Ten Years After the Exxon Valdez 

Oil Spill. Exxon Valdez Oil Spill Restoration Project Final Report (Restoration Project 

99471). Technical Paper No. 252. Alaska Department of Fish and Game, Division of 

Subsistence. 

http://www.subsistence.adfg.state.ak.us/TechPap/tp252.pdf

Hall, Jason E. 2002. Bio-concentration, bioaccumulation, and bio-magnification in Puget 

Sound biota: assessing the ecological risk of chemical contaminants in Puget Sound. 

Journal on the Environment, Volume 1. 

http://courses.washington.edu/uwtjoe/toc.html

Kissinger, Lon. 2005. Development of Tulalip Tribes’ Fish and Shellfish Consumption Rates 

for Puget Sound Tribal Seafood Risk Analysis, Based on Individual Interview Results. 

Internal EPA memorandum. March 9. 

Morgan, J.N., M.R. Berry, and R.L. Graves. 1997. Effects of commonly used cooking 

practices on total mercury concentration in fish and their impact on exposure assessments. 

Journal of Exposure Analysis and Environmental Epidemiology, 7: 119-133. 

Page 31 
National Congress of American Indians. 2004. Use of Tribal Fish Consumption Rates by the 

Environmental Protection Agency. Resolution #MOH-04-023. June 23. 

http://www.ncai.org/data/docs/resolution/midyear2004/04-023.pdf

O'Neill, S.M., J.E. West and J.C. Hoeman. 1998. Spatial trends in the concentration of 

polychlorinated biphenyls (PCBs) in Chinook (Oncorhynchus tshawtscha) and Coho 

salmon (O. Kisutch) in Puget Sound and factors affecting PCB accumulation: results from 

the Puget Sound ambient monitoring program. Pages 312-328 in E.R. Strickland, editor. 

Puget Sound Research ‘98 Proceedings. Puget Sound Water Quality Action Team, 

Seattle, WA. http://www.psat.wa.gov/Publications/98_proceedings/pdfs/2b_oneill.pdf

Roose, P. and U. Blindman. 2000. Volatile organic compounds in various marine organisms 

from the southern North Sea. Marine Pollution Bulletin 40(12):1167-1177. 

See also http://www.vliz.be/Vmdcdata/imis2/person.php?show=html&persid=701

Sechena, R., C. Nakano, S. Liao, N. Polissar, R. Lorenzana, S. Truong, and R. Fenske. 1999. 

Asian and Pacific Islander Seafood Consumption Study in King County, Washington. 

EPA 910/R-99-003, May. http://www.epa.gov/r10earth/offices/oea/risk/a&pi.pdf

Sherer, R.A. and P.S. Price. 1993. The effect of cooking processes on PCB levels in edible 

fish tissue. Quality Assurance: Good Practice, Regulation and Law, 2(4): 396-407. 

The Suquamish Tribe. 2000. Fish Consumption Survey of the Suquamish Indian Tribe of The 

Port Madison Indian Reservation, Puget Sound Region. August. 

The Suquamish Tribe. 2007. Selected Suquamish Tribe Seafood Ingestion Rates, Consumers 

Only. June 29. Prepared by Nayak Polissar, Ph.D. and Shiquan Liao, Ph.D. 

Toy, K.A., N.L. Polissar, S. Liao, and G.D. Mittelstaedt. 1996. A Fish Consumption Survey 

of the Tulalip and Squaxin Island Tribes of the Puget Sound Region. Tulalip Tribes, 

Department of Environment, Marysville, WA. 

Washington Department of Health. 2001. Health Consultation. Evaluation of Cadmium, 

Lead and Zinc Contamination in Spokane River Fish, Spokane, Spokane County, 

Washington, August 21. 

The White House. 1997. Executive Order 13045. Protection of Children From 

Environmental Health Risks and Safety Risks. 62 Fed. Reg. 19,883. April 23. 

http://www.epa.gov/fedrgstr/eo/eo13045.htm

Page 32 
Appendix A 

Development of the Framework for Selecting and Using Tribal Fish and Shellfish 

Consumption Rates for Risk-Based Decision Making at CERCLA and RCRA 

Cleanup Sites in Puget Sound and the Strait of Georgia 

 This document presents a conceptual Framework for a consistent approach for 

selecting and using Tribal fish and shellfish consumption rates for purposes of estimating 

site-related risks at U.S. Environmental Protection Agency (EPA) hazardous waste 

cleanup sites in Puget Sound and the portion of the Strait of Georgia that is within the 

United States. The decision to develop this Framework to support EPA Region 10 

RCRA and CERCLA risk-based decision making was made in 2003 by an executive 

team representing EPA Region 10’s Offices of Environmental Assessment; 

Environmental Cleanup; Air, Waste and Toxics; and Ecosystems, Tribal and Public 

Affairs. Professionals representing each of the first three offices were selected to be 

responsible to prepare a draft of the Framework, with the assistance of their colleagues as 

appropriate. Remedial project managers, permit writers, human health risk assessors, 

senior policy analysts and managers were among those representing Region 10 who 

contributed to this document. 

 The Framework was developed to be consistent with the following: 

1) EPA’s overarching mission to protect human health and to safeguard the natural 

environment upon which life depends; 

 

2) EPA Region 10’s commitment to protecting human health and the environment 

throughout the Region, including the lands and resources of Indian Tribes, while 

supporting Tribal self-government, fulfilling the federal trust responsibility, and 

strengthening the government to government relationship between the Tribes of our 

Region and EPA; and 

3) "Guidelines for Ensuring and Maximizing the Quality, Objectivity, Utility, and 

Integrity of Information Disseminated by the Environmental Protection Agency" (EPA, 

2002e). 

Selection and acquisition of Tribal survey data for incorporation into the Framework

 Two seafood consumption surveys that assess Tribal seafood consumption in 

Puget Sound and the Strait of Georgia were used by EPA in developing this Framework. 

Section III A. discusses methodological strengths of these surveys and why EPA chose to 

use the surveys. These surveys are the Suquamish Tribe (2000) survey, which addresses 

Suquamish Tribe seafood consumption, and the Toy et al. (1996) study, which addresses 

seafood consumption of the Squaxin Island and Tulalip Tribes. 

Appendix A - 1 
 The data as summarized in the Suquamish Tribe (2000) and Toy et al. (1996) 

study reports were not adequate to meet the needs of the Framework in that published 

survey results did not provide consumption rates for seafood harvested from Puget 

Sound. The need for this formulation of consumption rates derived from a policy 

decision that the fraction of seafood affected by site-specific contamination would be 

defined as the fraction of seafood harvested from Puget Sound. Rationale for this 

policy decision is provided in section VI.C. of the Framework. 

 The methodology used to compute consumption rates of seafood harvested from 

Puget Sound is provided in Appendix B. EPA initially analyzed the Toy et al. (1996) 

data on both the Tulalip and Squaxin Island Tribes. Permission to use the original 

data from the Toy et al. (1996) study was received from the Tulalip Tribes. Dr. 

Shiquan Liao, a statistician involved in data analysis for both the Toy et al. (1996) 

and Suquamish Tribe (2000) studies, was custodian of the Toy et al. (1996) data and 

transmitted data for both the Tulalip and Squaxin Island Tribe data to EPA. In 

consultations with the Squaxin Island Tribe, it was later determined that the Tulalip 

Tribes’ permission to use the Toy et al. (1996) data did not include use of Squaxin 

Island Tribe data. Squaxin Island Tribe data analysis results included in an earlier 

draft of the Framework were subsequently withdrawn. EPA and the Squaxin Island 

Tribe reached the understanding that both parties would continue to discuss the 

potential use of the Squaxin Island Tribe’s data in a later version of the Framework. 

 The Suquamish Tribe data were not analyzed by EPA but rather by Dr. Liao, as 

the Suquamish Tribe has chosen to retain custody of its data. EPA explained the need 

for this data analysis to the Suquamish Tribe environmental staff, who then gave 

permission to Dr. Liao to conduct his analysis and transmit the results to EPA. Dr. 

Liao’s analysis was used to support the Suquamish Tribe consumption rate used in 

this Framework. 

 

 During the development of the Framework, national EPA guidance and policies 

were reviewed, as were historic Region 10 site-specific approaches to the selection of 

fish and shellfish consumption rates for cleanup sites. 

Review of the draft Framework

 The initial draft Framework underwent extensive internal review by staff and 

managers within the participating offices, the Office of Ecosystems, Tribal and Public 

Affairs, and by the Senior Tribal Policy Advisor. After incorporating numerous 

changes based on review comments, in December 2004 the draft Framework was sent 

to the chairpersons of all the federally-recognized Tribes in Puget Sound and the 

Strait of Georgia, listed below. Copies of the letter and Framework were also sent to 

Appendix A - 2 
an environmental director or staff person at each Tribe, based on information 

collected during a phone call to each Tribe. 

 

Jamestown S'Klallam Tribe Port Gamble S'Klallam Tribe 

Muckleshoot Tribe Chehalis Tribe 

Swinomish Tribe Suquamish Tribe 

Lower Elwha Klallam Tribe Nooksack Tribe 

Suak-Suaittle Tribe Lummi Nation 

Makah Tribe Samish Indian Tribe 

Stillaquamish Tribe Skokomish Tribe 

Tulalip Tribes Nisqually Tribe 

Puyallup Tribal Council Yakama Nation 

Squaxin Island Tribe Upper Skagit Tribe 

Snoqualmie Tribal Council 

 The Tribes were asked to participate in a dialogue on the draft Framework, and 

meetings between EPA and individual or multiple Tribes were encouraged. EPA invited 

the Tribes named above to an initial conference call on January 11, 2005, to present the 

draft Framework and discuss the anticipated process for meetings and the submittal of 

comments. EPA met with the Water Quality Group of the NW Indian Fisheries 

Commission on February 2, 2005 and September 9, 2005, and with the Suquamish Tribe 

on December 6 and December 15, 2005. In March 2005, a Web-based "QuickPlace" was 

set up by EPA to facilitate dialogue among Tribes and with EPA regarding the draft 

Framework. Oral or written comments additionally were received from four Tribes As a 

result of these comments and conversations, EPA made numerous additional changes to 

be responsive to comments from these Tribes and sent revised versions of the draft 

Framework to all the Tribal chairpersons with copies to their natural resource or 

environmental director or staff person on March 23, 2005, October 11, 2005, and 

February 22, 2006. 

 The draft Framework went through more extensive internal reviews and revisions, 

resulting in a draft final version, which was transmitted to all the Tribes in March 2006. 

The proposed changes were also presented to the Water Quality Group of the NW Indian 

Fisheries Commission in June 2006. EPA continued to work with the Suquamish Tribe 

during the summer of 2006 in order to address its concerns. Several elements of the 

Framework were modified as a result of these conversations, and these changes are 

described in EPA’s transmittal letter to the Tribes, dated August 2007. 

In spring 2007, while EPA and the Suquamish Tribe were working with the 

Suquamish Tribe’s data, a discrepancy between the consumption calculations in the data 

and those used in the Framework was recognized. The Suquamish Tribe reviewed the 

data and modified its consumption rate. This change is also described in EPA’s 

transmittal letter to the Tribes. 

Appendix A - 3 
 As explained to the Tribes in December 2004, EPA needed to use the Framework 

as a pilot, that is, before it would be finalized, at one or more cleanup sites affecting the 

Duwamish River. It is currently being used in the Superfund Lower Duwamish 

Waterway risk assessment. Lessons learned from the pilot application of the Framework 

have been incorporated into this version. 

 In summary, this Framework provides a recommended approach for selecting fish 

and shellfish consumption rates where Tribal consumption of fish and shellfish is 

evaluated in EPA’s risk assessment process for CERCLA and EPA-lead RCRA sites in 

Puget Sound and the Strait of Georgia. The approach reflects EPA guidance and policies 

regarding the exposures due to releases from contaminated sites. The Framework is 

designed to provide a consistent approach to developing fish and shellfish consumption 

rates and to assist decision makers in making risk management decisions. 

 Application of this Framework in EPA’s RCRA and CERCLA cleanup programs 

is expected to be performed in consultation with the Tribal governments on a site-specific 

basis. This Framework is not intended to replace government-to-government 

consultation on specific sites. 

 EPA’s release of the Framework does not imply concurrence by the Tribes. The 

Framework is an EPA cleanup program document that has been improved through 

dialogue with Tribes. Nevertheless, EPA's release of the Framework should not be 

construed as any Tribe's concurrence with either the Framework in general or any 

specific statements or recommendations included in the Framework. 

 EPA considers the Framework to be a working document that may be revised 

periodically to incorporate new information and lessons learned. 

 Nothing in the Framework will limit, modify, or change Tribal treaty rights. 

Appendix A - 4 
Appendix B 

Fish and Shellfish Mixtures from Tribal Consumption Studies 

 The consumption rate in grams per day for each group of species listed in Appendix B, 

including salmon, was calculated using the following steps: 

1. The mean consumption rate for adult Tribal members for each group of species was 

taken from averages reported in Toy et al. (1996) and the Suquamish Tribe (2000). 

2. The mean consumption rates were added, and this sum was used to estimate the 

percentage of total fish consumption ascribed to each group of species. This estimate 

is presented in the column “Percent of Diet.” 

3. These percentages were applied to the total ingestion rate selected in Box PS-9 to 

calculate an estimated consumption rate (g/day) for each group of species. 

Step 2, Box PS-10 of this Framework requires the user to select a “reasonable mix of 

classes of fish and shellfish.” The following tables specify such mixes for the Tulalip and 

Suquamish Tribes. 

Table B-1. 

Distribution among species groups if the Tulalip Tribes consumption rate is used in Box 

PS-9 

Species Grams per day (1) Percent of diet (2)

Salmon 96.4 49.7 

Pelagic fish 8.1 4.2 

Bottom fish 7.5 3.9 

Shellfish 81.9 42.2 

Total Ingestion Rate 194 (3) 100 

(1) The average body weight for use with this study is 81.8 kg. 

(2) Percent of diet is based upon mean data in Table 3, Toy et al., 1996. 

(3) The value of 194 g/day in this table is the 95th percentile total consumption rate for 

fish and shellfish after adjusting the total consumption rate of 243 g/day to include 

only fish and shellfish harvested from Puget Sound, Kissinger, 2005. 

Appendix B - 1 
Table B-2. 

Distribution among species groups if the Suquamish Tribe 

 consumption rate is used in Box PS-9. 

Species Grams per day (1) Percent of diet (2)

Salmon (Group A) 183.5 23.9 

Pelagic Fish (Groups B and C) 56.0 7.3 

Bottom Fish (Group D) 29.1 3.8 

Shellfish (Groups E and G) 498.4 65 

Total Ingestion Rate 766.8 (3) 100 

(1) The average body weight for use with this study is 79 kg. 

(2) Percent of diet is based upon mean data in Table T-3, The Suquamish Tribe, 2000. 

Group F is primarily canned and fresh tuna and is not included in these calculations. 

(3) The value of 766.8 g/day in this table is the 95th percentile total consumption rate for fish 

and shellfish after adjusting the total consumption rate of 796 g/day to include only fish and 

shellfish harvested from Puget Sound, The Suquamish Tribe, 2007 

Appendix B - 2 
Appendix C 

Background Information on the Calculation of Puget Sound 

Fish and Shellfish Consumption Rates

 The 95th percentile, consumer-only Puget Sound fish and shellfish consumption rate 

for the Tulalip and Suquamish Tribes, as shown in Step 2, Box PS-9 of this Framework, was 

determined as follows. For each individual, the consumption rate was obtained for each fish 

and shellfish group (i.e., bottom, pelagic, anadromous, and shellfish). The consumption rate 

for each group was then multiplied by the fraction of that group obtained by the individual 

from Puget Sound. The overall consumption rate of fish and shellfish harvested from Puget 

Sound for each individual was derived by summing all of the adjusted results. 

RateA: Anadromous fish consumption rate, g/kg/day 

FPSA: Fraction of anadromous fish harvested from Puget Sound (unitless) 

RateP: Pelagic fish consumption rate, g/kg/day 

FPSP: Fraction of pelagic fish harvested from Puget Sound (unitless) 

RateB: Bottom fish consumption rate, g/kg/day 

FPSB: Fraction of bottom fish harvested from Puget Sound (unitless) 

RateS: Shellfish consumption rate, g/kg/day 

FPSS: Fraction of shellfish harvested from Puget Sound (unitless) 

BW: Body weight, kg 

Rate (g/day) = [RateA * FPSA + RateP * FPSP + RateB * FPSB + RateS *FPSS] * BW 

 

 After a Puget Sound fish and shellfish consumption rate was computed for each 

individual, rates were ranked from lowest to highest consumption rate. Results for 

individuals who did not consume any fish harvested from Puget Sound (non-consumers) 

were discarded from the analysis. From rates for the remaining individuals (i.e., 

consumers), the rank of the 95th percentile respondent was identified by multiplying the 

number of consumers by 0.95. Where this computation did not result in a whole number 

rank that identified a specific individual and associated consumption rate, the 95th 

percentile consumption rate was linearly interpolated from the rates of the individuals 

bracketing the position of the 95th percentile rank (Kissinger, 2005; The Suquamish 

Tribe, 2007) 

Appendix C - 1 
Appendix D 

Section IV Applied to a Simple Hypothetical Site 

Background

 A hypothetical site in Puget Sound is within the U&A of the ABC Tribe. The site 

has released only one contaminant, X, to groundwater, surface water and sediments. X 

has cancer and noncancer toxicity values available on the IRIS database. The 

contaminant is prevalent throughout Puget Sound and the Strait of Georgia waters and is 

bioaccumulative. The exposure duration for the ABC Tribe is assumed to be the 

Framework’s default of 70 years, as there is no site-specific information indicating that 

Tribal members consume fish and shellfish from their U&A for fewer than 70 years 

during their lifetimes. 

Site-specific considerations (see Section IV and the Flow Sheet)

Box PS-1: Are Puget Sound fish and shellfish consumption studies relevant? 

There are no obvious reasons why any of the existing Puget Sound studies are 

inappropriate for characterization of the ABC Tribe’s seafood consumption. Proceed to 

Box PS-2. 

Box PS-2: Does the site have extensive shellfish habitat? 

The site has limited intertidal habitat. Consequently, proceed to Box PS-5. 

Box PS-5: What Tribal study is appropriate for sites with limited shellfish habitat? 

For sites with limited intertidal habitat, use Tulalip Tribes data to characterize the 

consumption rate. Proceed to Box PS-8. 

Box PS-8: Proceed to Box PS-9, Selection of a consumption rate. 

Box PS-9: Consult the table in Box PS-9 associating the Tribe and the consumption rate. 

The consumption rate associated with the Tulalip Tribes is 194 g/day. Proceed to Box 

PS-10. 

Box PS-10: What are appropriate percentages of the different fish and shellfish 

categories? 

It is determined that the percentages for the Tulalip Tribes as provided in Appendix B, 

Table B-1 are appropriate. These are as follows, along with consumption rates: 

Appendix D - 1 
Species Grams per day Percent of diet

Salmon 96.4 49.7 

Pelagic fish 8.1 4.2 

Bottom fish 7.5 3.9 

Shellfish 81.9 42.2 

Total Ingestion Rate 194 100 

Proceed to Box PS-11 

Box PS-11: Are salmon affected by local contamination? 

Adult salmon returning to spawn are known to reside in the general vicinity of the 

cleanup site for a few days to a week, during which time they are not feeding. The 

contaminant is known to be readily accumulated by salmon via the food chain. Adult 

salmon harvested from the vicinity of the site have concentrations of contaminant X that 

are similar to those found in salmon harvested in other areas within Puget Sound and the 

Strait of Georgia. While the site has released contaminant X, the lines of evidence 

indicate that the preponderance of the adult salmon’s body burden of contaminant X was 

probably acquired in the open ocean or other areas of Puget Sound and the Strait of 

Georgia, remote from the site. The degree to which site-related releases of contaminant 

X may have been transported to more remote areas of Puget Sound and the Strait of 

Georgia is unknown. A best professional judgment decision is made to not include the 

contaminant present in locally harvested salmon in the calculation of site-related risk 

from fish and shellfish consumption. This decision and rationale are discussed with the 

EPA Region 10 advisory inter-program review group. 

Box PS-12: Are there any additional issues to consider in determining whether or not the 

contaminant might pose site-related risks via consumption of other categories of fish or 

shellfish? 

 There are no additional contaminant and aquatic life issues. Bottom and pelagic fish 

and shellfish tissue of representative species will be sampled and the results of the 

analysis used in the risk assessment. [Note: concentrations in these fish could also be 

estimated through modeling, if appropriate.] 

Calculating the intake rate of the contaminant

 The intake rate of the contaminant via consumption of fish and shellfish tissue may 

be computed from the following formula. This formula is used to compute the intake rate 

of the contaminant based on tissue concentrations in each category of fish/shellfish, and 

is specific to exposures to tissue contaminants that are expected to be potentially siterelated. The total site-related intake of contaminant X via fish and shellfish consumption 

is computed by summing the individual rates for each category. 

Appendix D - 2 
Intake of contaminant in mg/kg-day (IRc) = (CFi x CRPS x %i x UCF1) /BW 

[Equation 1] 

Where: 

IRc = Intake rate of contaminant X by category of fish/shellfish. 

CFi = contaminant concentration (milligrams per kilogram, mg/kg) in the tissue of the 

particular fish or shellfish category, (also referred to as the exposure point 

concentration). 

CRPS = the total consumption rate of fish and shellfish harvested from Puget Sound, 

194 grams per day. 

%i = the percentage of the ingestion rate that consists of the category of fish or 

shellfish, unitless (see table provided for box PS-10, above) 

BW = body weight, 81.8 kilograms, observed from the Tulalip Tribes’study (See 

Appendix B) 

UCF1 = conversion factor 1, 0.001 kilograms per gram 

Intake rates of Contaminant X, by category of fish/shellfish 

Overall 

Fish/Shellfish 

Consumption 

Rate, g/day 

Category Percent of 

Consumption 

Rate 

Represented by 

Category 

Site-related 

concentration of 

contaminant X, 

mg/kg, in fish 

tissue (1) 

CategorySpecific 

Exposure, 

mg/kg-day 

computed using 

Equation 1 

194 Salmon 49.7 0 (2) 0

194 Pelagic Fish 4.2 1.1 0.0001

194 Bottom Fish 3.9 3.1 0.0003

194 Shellfish 42.2 18.6 0.0186

Sum, IRtotal, 0.0190

(1) Concentrations from sampling of bottom and pelagic fish and shellfish. 

(2) Any amount of contaminant X present in salmon tissue is assumed in this case to be 

from sources remote from and unrelated to the site. 

The overall site-related intake rate of contaminant X, IRtotal, via fish and shellfish 

consumption is 0.0190 mg/kg-day. This value is now used with appropriate cancer and noncancer toxicity information to calculate the potential risks and hazards to Tribal members 

Appendix D - 3 
from consuming this quantity of contaminant X. This is conducted using routine risk 

algorithms, shown below. 

Cancer risk and non-cancer hazard estimates associated with

 site-related intake of Contaminant X

Oral cancer slope factor for Contaminant X Oral reference dose for Contaminant X 

1.4E-2 (mg/kg-day)-1 2E-2 mg/kg-day 

Estimated cancer risk = (IRtotal x ED x EF x CSF) / (AT x UCF2) [Equation 2]

Where: 

IRtotal = Total intake of contaminant X from site-related fish and shellfish consumption, 

0.0190 mg/kg-day 

ED = exposure duration, 70 years 

EF = exposure frequency, 365 days per year 

CSF = oral cancer slope factor for contaminant X, 1.4E-2 (mg/kg-day)-1

AT = averaging time, 70 years for carcinogens 

UCF2 = conversion factor 2, (365 days/year) 

Estimated cancer risk = 

 [ (.0190 mg/kg-day x 70 yr x 365 d/yr) x (1.4E-2 per mg/kg-day)] / [(70 years) x (365 

days/yr)] = 3E-4 

Appendix D - 4 
Estimated hazard index = (IRtotal x ED x EF x UCF2) / (RfD x AT) [Equation 3] 

Where: 

IRtotal = Total intake of contaminant X from site-related fish and shellfish consumption, 

0.0190 mg/kg-day 

ED = exposure duration, 70 years 

EF = exposure frequency, 365 days per year 

RfD = Oral reference dose for contaminant X, 2E-2 mg/kg-day 

AT = averaging time, the same as exposure duration for non-carcinogenic effects 

UCF2 = conversion factor 2, (1 yr/365 days) 

Estimated hazard index = (0.0190 mg/kg-day x 70 y x 365 d/y x 1 y/365 days) / (2E-2 

mg/kg-day x 70 years = 0.95 

Summary

The excess individual lifetime cancer risk from Tribal consumption of fish and shellfish that 

may be affected by site-related releases of contaminant X is estimated to be 3E-4. 

The hazard quotient from Tribal consumption of fish and shellfish that may be affected by 

site-related releases of contaminant X is estimated to be 0.95. 

These estimates, and their associated exposure and toxicity uncertainties, will be presented 

and evaluated in the risk characterization document to be used in making risk management 

decisions for the site. 

Appendix D - 5