01-9056. Notice of Availability of 2001 Update: Aquatic Life Criteria Document for Cadmium

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Notice of Availability of 2001 Update: Aquatic Life Criteria Document for Cadmium.

SUMMARY:

Section 304(a)(1) of the Clean Water Act requires the Environmental Protection Agency (EPA) to develop and publish, and from time to time revise, criteria for water accurately reflecting the latest scientific knowledge. EPA has revised its aquatic life criteria for cadmium and is notifying the public about the availability of the completed document in accordance with the Agency's new process for developing or revising criteria (63 FR 68354, December 10, 1998).

EPA notified the public about the availability of the draft document and the peer review on August 17, 2000 (65 FR 50201). At that time, the Agency 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.

ADDRESSES:

Copies of the completed criteria document entitled, 2001 Update of Ambient Water Quality Criteria for Cadmium, may be obtained from EPA's National Services Center for Environmental Publications (NSCEP formally NCEPI) by phone at 800-490-9198, or by e-mail to [e-mail] or by conventional mail to U.S. EPA/NSCEP, P.O. Box 42419, Cincinnati, Ohio, USA, 45242-2419. Alternatively, the document and related fact sheet can be obtained from EPA's web site at http://www.epa.gov/​waterscience/​criteria/​ on the Internet.

FOR FURTHER INFORMATION CONTACT:

Cindy Roberts, Health and Ecological Criteria Division (4304), US EPA, Ariel Rios Building, 1200 Pennsylvania Avenue NW., Washington, DC 20460; [phone]; [e-mail]

SUPPLEMENTARY INFORMATION:

What Are Water Quality Criteria?

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

Under the CWA, 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 is it a regulation itself. Thus, EPA's recommended water quality criteria cannot impose legally binding requirements on EPA, States, Tribes or any other regulated community, and may not apply to a particular situation based on the circumstances. 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.

EPA emphasizes that, in the course of carrying out its responsibilities under section 303(c), it reviews State and Tribal water quality standards to assess the need for new or revised water quality criteria. EPA generally believes that five years from the date of EPA's publication of new or revised water quality criteria is a reasonable time by which States and authorized Tribes should take action to adopt new or revised water quality criteria necessary to protect the designated uses of their waters. This period is intended to accommodate those State and authorized Tribes that have begun a triennial review and wish to complete the action they have underway, deferring initiating adoption of new or revised section 304(a) criteria until the next triennial review. Thus, EPA expects State and authorized Tribes to adopt criteria for cadmium that ensure the protection of designated uses no later than 2006.

How Did EPA Involve the Public in Revising the Aquatic Life Criteria for Cadmium?

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 FR 58409). 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 FR 50201). 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.

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 FR 68354) and in the EPA document entitled, National Recommended Water Quality—Correction (EPA 822-Z-99-001, April 1999). The purpose of the revised process is to provide expanded opportunities for public input, and to make the criteria development process more efficient.

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 CMC and CCC.

The freshwater CMC 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 (SMAVs) for a few species. Two SMAVs 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 CCC compared to the draft document. The revised CCC, however, is still more stringent than EPA's 1995 CCC.

A number of comments were received stating that EPA should not proceed with the cadmium update until the biotic ligand model (BLM), a model that estimates the bioavailable portion of dissolved metals in the water column based on site-specific water quality parameters such as alkalinity, pH and dissolved organic carbon, is available for cadmium. To date, EPA has not completed any BLM criteria and is still in the preliminary evaluation phase of the model for cadmium and so does not agree that the update should wait for the development of the BLM. The cadmium criteria may be revised in the future based on the BLM, yet development is contingent upon resources and sufficient data being available to develop the model.

What Are the New Criteria?

	Fresh water 1		Salt water
	CMC (μg/L)	CCC (μg/L)	CMC (μg/L)	CCC (μg/L)
Total	e(1.0166[ln(hardness)]-3.924)	e(.7409[ln(hardness)]-4.719)	40.28	8.846
Dissolved	1.0	0.15	40	8.8

1-@ 50 mg/L hardness measured as CaCO₃

CMC conversion factor = 1.136672 − [(ln hardness)(0.041838)]

CCC conversion factor = 1.101672 − [(ln hardness)(0.041838)]

Dated: April 4, 2001.

Geoffrey H. Grubbs,

Director, Office of Science and Technology.