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| Aquatic LifeAtrazineNotice of Revised Draft Ambient Water Quality Criteria Document               for Atrazine and Request for Scientific ViewsFact Sheet: EPA-822-F-03-006; November 2003- Summary
- Background
- What are the revised draft atrazine criteria                 concentrations?
- How are the revised criteria in today's publication                 different from the 2001 criteria? 
- How do I get a copy of the new draft atrazine                 document?

**Summary**

EPA has released and requested scientific views on a revised draft               ambient water quality criteria document for atrazine. We developed               acute and chronic criteria recommendations for atrazine designed               to protect aquatic life in both freshwater and saltwater. At the               same time, EPA released its revised Ecological Fate and Effects               Risk Assessment for atrazine. Both documents incorporate our responses               to additional information that became available after we published               the earlier draft criteria atrazine water quality criteria document.

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**Background**

Atrazine is an herbicide used throughout the U.S. to control weeds               in agricultural crops. It is moderately volatile, soluble in water,               and resistant to natural degradation in water. Because of its chemical               properties and widespread use as an herbicide, concerns have been               raised over the risks it poses for both freshwater and saltwater               organisms. 

On September 26, 2001, the Agency published a draft criteria document               and requested scientific views and information. EPA then extended               the period for scientific information to close on Janaury 25, 2002,               to allow all interested parties the opportunity to submit scientific               views. The revised draft criteria document reflects the results               of our consideration of the additional information that became available               on scientific issues related to deriving the atrazine criteria and               on the risk assessment methods we used.

The revised draft ambient water quality criteria document for atrazine               contains ambient water quality criteria designed to protect aquatic               organisms and their uses. Once final, these criteria are guidance               for states and tribes and, in themselves, have no binding legal               effect. However, they may form the basis for state water quality               standards and become enforceable through NPDES permits or other               environmental programs. These new draft atrazine criteria are published               pursuant to Section 304(a) of the Clean Water Act (CWA).

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**What are the revised draft atrazine criteria               concentrations?**

*Freshwater Aquatic Life:*              Except possibly where a locally important species is very sensitive,               freshwater aquatic life and their uses should not be affected unacceptably               if the one-hour average concentration of atrazine does not exceed               1,500 ug/L more than once every three years on the average (acute               criterion) and if the Average Primary Producer Steinhaus Similarity               deviation for a site is less than 5% (as determined using Comprehensive               Aquatic Systems Model (CASM) or other appropriate model and index)               and is not exceeded more than once every three years (or other appropriate               return frequency sufficient to allow system recovery). The 5% index               for the protection of aquatic plant community should also be protective               of most freshwater animals (chronic criterion).

*Saltwater Aquatic Life:*              Except possibly where a locally important species is very sensitive,               saltwater aquatic life and their uses should not be affected unacceptably               if the one-hour average concentration of atrazine does not exceed               760 ug/L more than once every three years on the average (acute               criterion) and if the thirty-day average concentration of atrazine               does not exceed 17 ug/L more than once every three years on the               average (chronic criterion).

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**How are the revised criteria in today's publication               different from the 2001 criteria?**

The revised criteria in today's publication incorporate information               on the toxicity of atrazine to aquatic plants and invertebrates               that had not been available at the time of the 2001 publication.               The change in critical endpoints reflects the scientific views received               from the public.

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**How do I get a copy of the new draft atrazine               document?**

You can get copies of "Ambient Aquatic Life Water Quality               Criteria for Atrazine - Revised Draft" (EPA-822-R-03-023) from               EPA's Water Resource               Center by calling (202) 566-1729. You can request a copy by               sending an e-mail to center.water.resource@epa.gov or by conventional               mail to: EPA Water Resource Center, 4101T, 1200 Pennsylvania Avenue,               N.W., Washington, DC 20460. You can also download the document from               EPA's web site at: http://www.epa.gov/waterscience/criteria/atrazine/atrazref.html.

The               Office of Pesticide Program's Ecological Fate and Effects Risk Assessment               for atrazine

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