United States Office of Water EPA-822-F-02-001 

Environmental Protection 4304T November 2002 

Agency 

Fact Sheet 

Revision of National Recommended Water Quality Criteria: 2002 

Summary

EPA has revised its national recommended water quality criteria for 83 chemical criteria to 

protect human health. These updated criteria supercede any published in EPA’s previous 

criteria compilations including the “Blue Book,” “Red Book,” “Gold Book” and EPA’s last 

compilation published in April 1999. 

Background

The Clean Water Act (CWA) requires EPA to 

publish and periodically update ambient 

water quality criteria. These criteria are 

intended to “. . . accurately reflect the latest 

scientific knowledge . . . on the kind and 

extent of all identifiable effects on health and 

welfare including, but not limited to, plankton, 

fish, shellfish, wildlife, plant life . . . which may 

be expected from the presence of pollutants 

in any body of water . . .” 

Water quality criteria developed under 

section 304(a) of the Clean Water Act are 

based solely on data and scientific judgments 

on the relationship between pollutant 

concentrations and environmental and 

human health effects. EPA’s national 

recommended water quality criteria are 

guidance for states and tribes in adopting 

water quality standards under section 303(c) 

of the CWA. These water quality criteria are 

not regulations and do not impose legally 

binding requirements on EPA, states, 

authorized tribes or the public. 

The revised national recommended water 

quality criteria may, however, be superceded 

by the publication of 304(a) criteria after the 

publication of this update. 

What’s new in the updated 

compilation?

The 83 revised human health criteria have 

been recalculated based on EPA’s new 

methodology entitled, Methodology for 

Deriving Ambient Water Quality Criteria for 

the Protection of Human Health (2000) (EPA822-B-00-004). This is a partial update 

based on a comprehensive revision of 

components of the 304(a) criteria. Partial 

updates represent a way of increasing the 

frequency of scientific improvements to the 

nationally recommended criteria. The revised 

human health criteria specifically integrate 

the new fish consumption rate of 17.5 

grams/day, relative source contribution (RSC) 

factors obtained from primary drinking water 

standards, and any new cancer potency 

factors (q1*s) or reference doses (RfDs) in 

the Agency’s Integrated Risk Information 

System (IRIS). 

The criteria do not incorporate bioaccumulation factors (BAFs), a component of the 

new methodology. Rather, the criteria rely on 

bioconcentration factors (BCFs). EPA 

intends to focus resources on developing 

BAFs for pollutants that the Agency considers 

of high priority and national importance, due 

to the comparative complexity of developing 

this component. The revised human health 

criteria are more stringent than those 

previously published, however, they are 

consistent with the criteria updates in the 

recently published compilation. 

EPA is separately publishing partial updates 

for 15 criteria in the Federal Register 

because the revisions significantly change 

the numerical values. EPA will accept 

scientific views on these 15 criteria. This is 

consistent with the process for publishing 

criteria previously described in the April 1999 

compilation. 

Additional Information 

EPA’s updated national recommended water 

quality criteria compilation, including the 83 

revisions, is available in a report, National 

Recommended Water Quality Criteria: 2002 

(EPA-822-R-02-047). You can find it on the 
Internet at 

http://epa.gov/waterscience/criteria/ 

For additional information about EPA’s

compilation of national recommended water

quality criteria, contact:

Cindy Roberts

Health and Ecological Criteria Div. (4304T)

1200 Pennsylvania Ave., N.W.

Washington, D.C. 20460 

(202) 566-1124 

Roberts.Cindy@epa.gov