# Human Health 

# Ambient 

# Water Quality Criteria

# and Fish 

# Consumption 

# Rates Frequently

# Asked Questions Note the 

### answers below reflect existing 

## EPA policy 

## and guidance as articulated in the 

### 2000 

## Human Health 

## Methodology DISCLAIMER These Frequently

### Asked Questions 

## FAQs do not 

### impose legally binding 

### requirements on the 

# US Environmental Protection 

### Agency 

# EPA states tribes or the regulated 

## communitynor

## do they confer legal rights 

### orimpose legal obligations 

## upon any 

## memberof the public 

### The Clean 

## Water Act 

# CWA provisions 

### and the 

## EPA regulations described in this 

### document contain legally binding 

### requirements These 

## FAQs do not constitute 

### a regulation nor 

### do they 

### change or substitute for

### any

# CWA provision or the 

## EPA regulations 

### The general description provided here 

## may not apply

### to a particular situation 

### based 

## upon the 

### circumstances Interested parties are free to raise questions 

### about the 

### substance of these 

## FAQs and the appropriateness of their application 

### to

## a particular situation 

### The 

## EPA retains the discretion to 

### adopt approaches on a

## case

## bycase basis that differ 

### from those described in these 

## FAQs where appropriate These 

## FAQs are 

### a living 

### document and 

## may be revised periodically 

### without public 

### notice The 

## EPA welcomes public input 

### on these 

## FAQs at 

### any 

## time 

# Q1 What is 

### the goal of the 

## human health 

### ambient water quality criteria Clean 

## Water Act 

# CWA section 

## 303

# c

# 2A requires that 

### water quality standards 

# WQS protect “public health or

### welfare enhance the quality of the 

### water and serve the 

### purposes of the Act].” 

# CWA section 

## 101

# a2 establishes as a national goal “

### water quality 

### which provides for protection 

### and propagation of fish shellfish 

### and wildlife 

### and recreation in 

### and 

## on the 

## water wherever attainable.” 

## EPA has interpreted 

### the “fishable” 

### language in section 

## 101

# a2 to refer not only to protecting 

### water quality 

### so the fish 

### and shellfish thrive 

### but

## when caught they can also 

### be safely 

### eaten by

## humans Thus to 

### be consistent with section 

## 101

# a

# 2the applicable criteria for

### such “fishable” 

### designated uses 

## must not only protect the aquatic 

### organisms themselves but also protect 

## human health 

### through consumption of fish 

## and shellfish1

EPA’s 

## recommended 

## 304

# a water quality criteria 

### to protect these “fishable” designated 

## uses and accompanying risk

### assessment methodologies reflect the longstanding interpretation that 

### a designated 

### use consistent 

### with the goals of

### the Act 

## means that State 

### and Tribal

### waters should support safe 

### consumption of fish 

## and shellfish 

## EPA has consistently 

### implemented the 

### Clean 

## Water Act to 

### ensure that the total rate of 

### consumption of freshwater 

## and estuarine fish 

### and shellfish including estuarine species 

### harvested in 

### near coastal 

## waters reflects 

### consumption

1 See 

### memorandum from Geoffrey

# H Grubbs and Robert

# H Wayland October

### 2000 posted at 

### httpwater

### epagovscitechswguidance standardsupload

## 2000 

## 1031 standards shellfishpdfrates

### demonstrated by the population of

### concern In other 

## words EPAexpects that the standards will 

## be set to 

### enable residents to safely 

## consume from local 

### waters the 

## amount of fish 

### they would normally

## consume from all fresh 

### and estuarine 

### waters including estuarine species 

### harvested in 

### near coastal 

## waters EPAdoes not necessarily 

### expect all 

### consumers to eat only fish 

### from a single 

### State but individuals 

### orgroups should be able 

### to

## do sowithout concern for their 

### health It is also 

### important to avoid 

### anysuppression effect that 

## mayoccur 

## when a fish 

### consumption rate for

### a given subpopulation reflects 

### an artificially diminished level of 

### consumption froman appropriate baseline level of 

### consumption for that

### subpopulation because of a perception that fish are 

### contaminated with pollutants
This 

### approach is consistent 

### with a principle that every State 

### does its share to protect 

### people 

## who consume fish 

### and shellfish that originate 

### from multiplejurisdictions In 

### addition the goal of 

### water quality criteria for

## human health is

### to protect 

### people from exposure to pollutants 

### through fish 

### and water over a lifetime 

### and the goal of

### a State's 

### designated use should be that the 

### waters are safe 

### to fish in the context of

### the total 

### consumption pattern of its residents 

### Likewise because people are 

### expected to continue 

### consuming fish 

### and shellfish

### throughout their lifetime regardless of

## where they live

## and this 

### consumption leads to similar

### exposure to pollutants it is appropriate to derive protective 

## human health criteria in State 

## and Tribal 

### water quality standards 

### assuming a lifetimeof

### exposure Although the 

## human health 

### ambient water quality criteria 

# AWQC are 

### based 

## on chronic health effects 

### data both cancer 

### and noncancer effects the criteria are

### intended to also 

### be protective against 

### adverse effects that 

## may reasonably 

### be expected to occur as 

### a result of elevated acute 

### orshortterm exposures That is through the 

### use of conservative 

### assumptions with respect to 

### both toxicity 

### and exposure parameters the resulting

# AWQC should provide 

### adequate protection 

### not only for the general population 

### over a lifetimeof 

### exposure but also for special subpopulations 

# who because of high 

### water orfish intake 

### rates or 

### because of biological sensitivities 

### have an increased risk of receiving 

### a dose that 

### would elicit 

### adverse effects 

## The Agency recognizes that there 

## may be 

## some cases 

## where the

# AWQC based 

## on chronic toxicity 

## may not provide 

### adequate protection for a 

### subpopulation at special risk

### from shorter term exposures 

## The Agency encourages States Tribes 

## and others 

### employing the 

## 2000 

## Human Health 

### Methodology to give consideration 

### to such circumstances in deriving criteria to 

### ensure that 

### adequate protection is afforded to all identifiable 

### subpopulations 

# Q2What does the fish 

### consumption rate 

## FCR indicate in

### the calculation for 

## human health 

### ambient water quality criteria


### The FCR indicates 

### the 

## amount of fish 

### and shellfish in kilograms

## consumed by a person each 

## day For the 

### purposes of 

## human health 

### ambient water quality criteria the fish 

### and shellfish

### to 

## be reflected in

### the 

## FCR include all of

### the fish 

### and shellfish 

## consumed that are species 

### found infresh 

### and estuarine 

### waters including estuarine species 

### harvested in 

### near coastal 

## waters Because the overall goal of the criteria is

### to allow for

### a consumer to safely 

## consume from local 

### watersthe 

## amount of fish 

### they would normally 

## consume from all fresh 

### and estuarine 

### watersthe 

## FCR does include fish 

## and shellfish 

### from local 

### commercial aquaculture interstate 

### and international 

### sources It is 

### not necessary for the 

### FCR to include fish 

## and shellfish species 

### designated as 

### marine species as that 

### exposure is 

### addressed by relative source contribution 

### see question 

### 4 for

## more detail 

## However partitioning of fish 

### and shellfish into the different habitats in 

### order to 

### develop a FCR can only 

### be 

## done where sufficient 

### data are available for this 

### to 

## bedone in 

### a scientifically defensible

## manner

For 

## example if 

### a State 

### were to 

### determine through scientifically collected 

### data that its citizens 

## consumed 25 grams of fish 

### and shellfish 

### per day

## where 5 grams

## came from marine fish 

### 5 grams 

## came from a local fresh 

### water 

## stream 5 grams

## came from a neighboring state’s fresh 

### waters 5 grams

## came from international 

### importsof estuarine shellfish 

### and 5grams

## came from aquaculture of 

### a freshwater 

### species then the 

### FCR would be 20 grams per

## day Only the 

### marine fish 

## component would be excluded from the 

### FCR see discussion 

### below

## on relative 

### source contribution All of the 

### other components represent 

### the 

## amount of fish 

### and shellfish that could 

### be taken 

## and consumed from local 

### waters if 

### the consumerchose to 

### do 

## so 

# Q3How is

### the exposureto a pollutant 

## due to 

### marine fish 

### consumption accounted for in 

### the 

## human health 

### ambient water quality criteria 

## Human health 

### ambient water quality criteria are

### to account for all sources of

### exposure to the pollutants for

### which they are 

### developed The exposure to pollutants 

### from marine fish 

### and shellfish species that are

### not included in the fish 

### consumption rate 

### should 

## be accounted for in the relative source contribution 

## RSCwhen setting criteria for threshold 

## noncarcinogens 

## and 

## non linear

### carcinogens 

# Q4What does the relative 

### source contribution 

## RSC indicate in 

### the calculation for the 

## human health 

### ambient water quality criteria



### The relative 

### source contribution 

## component of the 

## human health 

### ambient water quality criteria 

# AWQC calculation for threshold 

## noncarcinogens 

### and 

## non linear carcinogens allows 

### a percentage of the reference dose’s 

### exposure to 

### be attributed 

### to ambient water and freshwater 

### and estuarine fish 

### consumption including estuarine species harvested in 

### near coastal 

## waters when there are other potential 

### exposure sources The rationale for this 

### approach is that for pollutants exhibiting threshold effects the objective of the 

# AWQC is to 

### ensure that 

### an individual’s total 

### exposure from all 

### sources does not exceed that threshold level 

### The RSC includes 

### but is not limited

## to exposure to a particular pollutant 

### from marine fish 

### consumption not included in

### the fish 

### consumption 

## rate 

## nonfish 

### food consumption fruits 

### vegetables 

## and grains dermal exposure and respiratory 

### exposure

In the 

### absence of scientific 

## data the application of

### the EPA’s default value of 

### 20 percent 

## RSC in calculating 

## 304

# a criteria 

### orestablishing State 

### orTribal 

### water quality standards 

### under Section

## 303

# c will 

### ensure that the designated 

### use for a 

### water 

## body is 

### protected This 

### 20 percent default for

### RSC can only

## be replaced 

## where sufficient 

### data are available to 

### develop a scientifically defensible alternative 

### value If appropriate scientific data 

### demonstrating that other sources 

### and routes of 

### exposure besides 

### water 

## and freshwaterestuarine fish are not anticipated for the pollutant in 

### question then the 

### RSC 

## maybe raised to the appropriate level 

### based on the 

## data but not to 

### exceed 80 percent 

## The 80 percent ceiling accounts for the fact that 

## some sources of 

### exposure 

## maybe 

## unknown In cases 

### where an 80 percent 

## RSC is 

## used 20 percent of the 

### exposure is reserved for

## unknown sources Although the 

### 20 percent RSC has not 

### been consistently applied to national 

## 304

# a criteria 

### recommendations for

## noncarcinogenic pollutants 

## where there are inconsistencies 

### between the 

### 2000 

## Human Health 

### Methodology recommendation 

## and implementation in criteria 

### the 

## Human health 

### Methodology should prevail 

### and the 

### 20 percent 

## RSC applied 

## EPA is 

### moving to 

### complete implementation of this 

### guidance in existing

## 304

# a criteria 

# Q5 Should

## an RSC also 

### be applied to 

### carcinogens

In the 

### case of carcinogens 

### based 

## on linear

## lowdose extrapolation the 

# AWQC is 

### determined with respect 

### to the incremental lifetime risk

### posed by a substance’s 

### presence in 

## water and is 

### not being set with regard to 

### an individual’s total risk

### from all sources of 

### exposure 

## Thus the 

# AWQC represents the 

### water concentration that 

### would be expected to increase 

### an individual’s lifetime risk of carcinogenicity 

### fromexposure to the particular pollutant 

### by no 

## more than one chance in 

## one million regardless of the additional lifetime cancer risk

## due to 

### exposure if 

## any to that particular 

### substance from other 

### sources For

## human health criteria this 

### exposure pathway considers 

### consumption of

### freshwater 

## and estuarine fish 

## and shellfish as described in the 

### responses to 

## Q1 and 

# Q2and drinking 

### water ingestion 

## EPA recommends that the incremental cancer risk

### from these exposure pathways not exceed 

## more than 1 in 

### 1,000,000 or 

### 1 in 

### 100,000 for the general 

### population norexceed 

## more than 1 in 

### 10,000 for

### any sensitive 

## sub population 

### such as those 

## who mayconsume a great deal 

## more fish 

### because of a subsistence lifestyle States 

### and tribes 

## mayconsider adjusting the risk level according 

### to guidance in 

### the 2000 

## Human Health 

### Methodology 

## and mentioned 

## above particularly if 

### exposure to “other” sources besides 

### water and fish is 

### determined to 

### be significant 

# Q6 Could a state include 

### a

## component of marinefish 

### consumption in their 

### FCR forderiving 

## human health criteria 

## Yes a state 

## may include 

### consumption of 

### marine species in the 

## FCR Coastal States 

## and authorized Tribes that believe accounting for total fish 

### consumption i

# e freshwaterestuarine 

### and marine species is

## more appropriate forprotecting the population of

### concern 

## maydo

## so In the instance 

## where the 

## FCR includes 

### freshwater estuarine 

### and all 

### marine fish 

### consumption 

## EPA recommends that states adjust the 

### RSC estimate 

### to reflect a greater proportion of the reference 

### dose being attributed 

### towater intake 

## and the 

## marineinclusive 

## FCRexposuresIncluding 

### marine fish in

### the fish 

### consumption rate 

## may be particularly appropriate if a large proportion of fish 

### consumption for the population to 

### be protected consists of 

### marine fish 

### such as 

## salmon and this 

### exposure is clearly

## documented Including 

### marine fish in the fish 

### consumption rate forcriteria calculations 

### would provide 

## some calculations that are 

## more stringent 

### than those that don’t include 

### marine fish 

### consumption particularly for chemicals that are highly 

### bioaccumulative 

# Q7When fish 

### consumption exposure is 

### represented by a distribution of 

### values 

## what are the appropriate percentiles to 

## choose

In 

### general 

## EPA considers protection of the general population to 

### be represented by the 

### 90th percentile of 

### a total 

### exposure distribution utilizing 

### a “per capita” fish 

### consumption distribution

If 

### present in

### the state subsistence fishers

### should 

## be considered on a site specific 

### basis 

## EPA has 

## recommended the 99th percentile of

### a per capita fish 

### consumption distribution as a surrogate for subsistence fishers

### which corresponded to a 

### range of

### average consumption estimates

### from actual surveys for subsistence fishers

## An analysis of protectiveness of the criteria for the general 

### population recreational fishers

### and subsistence fishers

### should be included in the criteria 

### documentation

January 

# 18 2013