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Water Quality Standards: Establishment of Numeric Criteria for Priority Toxic Pollutants for the State of California (California Toxics Rule)

On May 18, 2000, the EPA promulgated numeric water quality criteria for priority toxic pollutants and other provisions for water quality standards to be applied to waters in the state of California. EPA promulgated this rule - also known as the California Toxics Rule (CTR) - based on the Administrator's determination that the numeric criteria are necessary in California to protect human health and the environment.

The CTR fills a gap in California water quality standards that was created in 1994 when a state court overturned the state's water quality control plans containing water quality criteria for priority toxic pollutants. Thus, the State of California has been without numeric water quality criteria for many priority toxic pollutants as required by the Clean Water Act, necessitating this action by EPA. These federal criteria are legally applicable in the state of California for inland surface waters, enclosed bays and estuaries for all purposes and programs under the Clean Water Act.


Endangered Species Act, Selenium, and the California Toxics Rule

(Updated September, 2011)

Pursuant to section 7(a) of the Endangered Species Act, EPA has consulted with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service (collectively the Services) concerning the California Toxics Rule. After lengthy discussions with EPA, on March 24, 2000, the Services issued a joint biological opinion finding that EPA’s action would not likely jeopardize the continued existence of any federally listed threatened or endangered species or result in the destruction or adverse modification of designated critical habitat. In order to ensure the continued protection of federally listed species and to protect their critical habitat, EPA agreed to several follow up actions, and the Services included several terms and conditions, which implement reasonable and prudent measures, in the biological opinion. For selenium, the terms and conditions include reevaluating and revising selenium criteria for the protection of aquatic and aquatic-dependent wildlife.

As part of these terms and conditions, the Services and EPA agreed that USGS would model the fate and transport of selenium in San Francisco Bay and Delta, an area known to be home to many sensitive aquatic and aquatic-dependent wildlife species. It was further agreed that EPA would review the information in the report and consider it during development of revised water quality criteria for the protection of wildlife species in the estuary.

USGS modeled selenium fate and transport in the San Francisco Bay and Delta in a report entitled, Ecosystem-Scale Selenium Modeling in Support of Fish and Wildlife Criteria Development for the San Francisco Bay-Delta Estuary, California, Administrative Report, Presser and Luoma, U.S. Geological Survey, Menlo Park, California, December 2010.

EPA is making this report available to the public.

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