EPA Publishes Final Water Quality Criteria For Diazinon, Nonylphenol

On Feb. 23, EPA made available the final recommended aquatic life water-quality criteria for diazinon and nonylphenol.

Diazinon is an organophosphorus pesticide traditionally used throughout the United States to control insects in agricultural areas, households and urban settings. While it became unlawful to sell diazinon for residential uses in the United States after December 2004, it is still lawful to use diazinon properly for non-residential or agricultural uses. Diazinon is frequently found in wastewater treatment plant effluent and stormwater runoff in urban and agricultural areas. Diazinon is toxic to aquatic life, particularly invertebrates.

The final recommended aquatic life water quality criteria document for diazinon contains acute and chronic criteria recommendations designed to protect aquatic life in both freshwater and saltwater. While these criteria recommendations do not, in themselves, impose any requirements, states and authorized tribes can use them to develop water quality standards.

Additional information on the final recommended aquatic life water quality criteria for diazinon, including a Feb. 23 Federal Register notice, can be accessed at http://www.epa.gov/waterscience/criteria/diazinon.

Produced in large quantities in the United States, nonylphenol is an organic chemical that is toxic to aquatic life. It is often found in wastewater treatment plant effluent as a breakdown product from surfactants and detergents.

The final criteria for nonylphenol 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 National Pollutant Discharge Elimination System (NPDES) permits or other environmental programs.

Additional information on the final recommended aquatic life water quality criteria for nonylphenol, including a Feb. 23 Federal Register notice, can be accessed at http://www.epa.gov/waterscience/criteria/nonylphenol.

An EPA recommended water quality criterion is a level of a pollutant or other measurable substance in water that, when met, will protect aquatic life and/or human health. Section 304(a) of the Clean Water Act requires EPA to develop and publish and, from time to time, revise recommended water quality criteria to accurately reflect the latest scientific knowledge.

"This is an important addition to the Clean Water Act toolbox," said Benjamin H. Grumbles, assistant administrator for Water. "EPA's scientifically-based criteria for pesticides, such as diazinon, and for organic chemicals, such as nonylphenol, help states and tribes set standards to protect watersheds, fish and wildlife."

This article originally appeared in the 03/01/2006 issue of Environmental Protection.

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