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| Aquatic LifeCadmiumFact Sheet: Notice of Availability United States                     Environmental Protection                    Agency Office of Water                    4304EPA-822-F-01-002                    April 2001

***Summary***

*The U.S. Environmental Protection Agency (EPA) has revised              its aquatic life criteria for cadmium and announced the availability              of the completed document entitled, 2001 Update of Ambient Water              Quality Criteria for Cadmium. EPA revised its aquatic life criteria              for cadmium to reflect the latest scientific knowledge regarding              the effects of cadmium on aquatic organisms. The revised criteria              are average concentrations of cadmium that can be present in a water              body, but should not result in unacceptable effects on aquatic organisms              and their uses.*

**Background**

Section 304(a)(1) of the Clean Water Act requires the EPA to develop,              publish, and from time to time revise, criteria for water. Water              quality criteria developed under section 304(a) are based solely              on data and scientific judgments and should accurately reflect the              latest scientific knowledge. They do not consider economic impacts              or the technological feasibility of meeting the criteria in ambient              water.

Under the Clean Water Act, States and Tribes are to establish water              quality criteria to protect designated uses. EPA has promulgated              regulations to implement this requirement (see 40 CFR part 141).              EPA's recommended water quality criteria do not substitute for the              Act or regulations, nor are they regulations themselves. Thus, EPA's              recommended water quality criteria cannot impose legally binding              requirements on EPA, States, Tribes or other regulated community.              State and Tribal decisionmakers retain the discretion to adopt approaches              on a case-by-case basis that differ from this guidance when appropriate.              EPA may change this guidance in the future.

**How does this new criteria for cadmium protect water quality?**

The updated cadmium criteria reflects the latest scientific data              and results in criteria that better protect aquatic organisms. Section              304(a) criteria provide guidance in adopting water quality standards              and provide a scientific basis to develop controls of discharges              or releases of pollutants. The criteria also provide a scientific              basis for EPA to develop federal regulations under section 303(c).

**Why is EPA notifying the public about the completed cadmium              document?**

EPA is notifying the public about the availability of the completed              criteria document entitled, 2001 Update of Ambient Water Quality              Criteria For Cadmium, according to its new process for developing              criteria (63 FR68354). In following the Agency's new process for              developing criteria, EPA notified the public of its intentions to              revise the aquatic life criteria for cadmium in the Federal Register              on October 29, 1999 (64 FR58409). At that time, EPA made available              to the public all references identified by a recent literature review              and solicited any additional pertinent data or scientific views              that would be useful in revising the aquatic life criteria. EPA              revised the aquatic life criteria for cadmium based on the new data              and prepared a draft document. EPA then announced the peer review              and the availability of the peer review draft on August 17, 2000              (65 FR50201). Again EPA solicited views from the public on issues              of science pertaining to the information used in deriving the draft              criteria. EPA considered the comments from the peer reviewers and              the public and has revised the document accordingly. The completed              document is now available.

**Where can I find more information on EPA's Revised Process              for Developing New or Revised Criteria?**

The Agency published detailed information about its revised process              for developing and revising criteria in the Federal Register on              December 10, 1998 (63 FR68354) and in the EPA document entitled,              *National              Recommended Water Quality-- Correction* (EPA 822-Z-99-001,              April 1999) (PDF, 292KB).

**Is the completed document different than the draft document?**

In addressing the peer reviewers' comments and the scientific issues              raised by the public, revisions were made to the draft document.              These revisions resulted in no changes in the saltwater criterion              maximum concentration (CMC or "acute criterion") or the saltwater              criterion continuous concentration (CCC or "chronic criterion"),              but did result in significant changes in the freshwater criterion              maximum concentration and the criterion continuous concentration.

The freshwater criterion maximum concentration changed due to several              factors including the addition of data for bull trout and rainbow              trout, the elimination of some data and the recalculation of species              mean acute values for a few species. Two species mean acute values              were recalculated based on all applicable data rather than only              giving preference to flow-through measured test results, as in the              draft. 

EPA's freshwater metals' criteria are expressed as hardness dependent              values because water quality characteristics such as hardness (and              other parameters that covary with hardness) influence the toxicity              of metals on aquatic organisms. Therefore, hardness slopes were              established to normalize all freshwater acute and chronic values              to the same hardness in order to derive the criteria. These hardness              slopes were revised in the completed document. The revision to the              acute slope was minor, but the chronic slope revision was more significant              and resulted in a less stringent criterion continuous concentration              compared to the draft document. The revised criterion continuous              concentration, however, is still more stringent than EPA's 1995              criterion continuous concentration.

**What are the revised criteria?**

***Freshwater***              criterion maximum concentration ug/L 

 e(1.0166[ln(hardness)]-3.924)

criterion continuous concentration ug/L 

 e(.7409[ln(hardness)]-4.719)

***Saltwater***              criterion maximum concentration ug/L 

 40 

              criterion continuous concentration ug/L 

 8.8 

**Additional Information**

For additional information contact Cindy Roberts, Health and Ecological              Criteria Division, US EPA, Ariel Rios Building, 1200 Pennsylvania              Avenue NW, Washington, D.C. 20460; (202) 566-1124; roberts.cindy@epa.gov

You may view the Federal Register notice and completed aquatic              life criteria document for cadmium at: http://www.epa.gov/waterscience/criteria/aqualife/cadmium/              on the Internet.

 

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