Diazinon and Pesticide-Related Toxicity in Urban Creeks TMDL

On May 16, 2007, the U.S. Environmental Protection Agency approved a Basin Plan amendment incorporating a TMDL and water quality attainment strategy for Diazinon and Pesticide-Related Toxicity in Urban Creeks. The amendment was adopted by the San Francisco Bay Regional Water Board on November 16, 2005, and the State Water Resources Control Board on November 15, 2006. The TMDL is incorporated into the Water Quality Control Plan for the San Francisco Bay Basin (Basin Plan), the region's master planning document for protecting water quality.

• Basin Plan amendment (pdf)
• Regional Water Board Resolution: R2-2005-0063 (pdf)
• Final Staff Report (pdf, 5MB)

Background:

In the 1990s, San Francisco Bay Area urban creeks were found to exceed water quality standards for aquatic toxicity, primarily due to runoff of the common insecticide diazinon. The insecticide diazinon was commonly used throughout the Bay Area to manage a broad spectrum of pests, such as ants and grubs. Although only a small fraction of the diazinon applied outdoors reached surface water, that fraction was sufficient to result in diazinon concentrations that were toxic to test organisms. The Diazinon and Pesticide-Related Toxicity in San Francisco Bay Area Urban Creeks TMDL and supporting documents examine this water quality problem, identify sources of diazinon, and set forth actions that will lead to a solution. As the TMDL was being developed in the early 2000s, it was evident that other pesticides with equal or greater aquatic toxicity would replace diazinon in the marketplace. Therefore, the TMDL addresses pesticide-related aquatic toxicity in general.

Implementation:

To address pesticide-related toxicity in urban water bodies, the TMDL contains a comprehensive implementation strategy. Federal, state, and local agencies, and others, are called on to take actions to reduce the potential for pesticides to runoff into waterways. Implementation actions focus on three areas:

1. Regulatory programs: use regulatory tools to ensure that pesticides are not applied in a manner that results in discharges that threaten urban creek beneficial uses.
2. Education and outreach programs: focus on decreasing demand for pesticides that threaten water quality, while increasing awareness of alternatives that pose less risk to water quality.
3. Research: fill information gaps and monitor to measure implementation progress.

Periodically, staff updates the Water Board on the status of these implementation actions:

• March 2011 Status Report
• August 2009 Status Report

The Municipal Regional Stormwater Permit (MRP) requires Permittees to implement a pesticide toxicity control program that addresses their own use of pesticides within their jurisdictions and to encourage residents to avoid using pesticides that pose a threat to water quality. MRP Permittees include municipalities and local agencies in Alameda, Contra Costa, San Mateo, and Santa Clara counties, and the cities of Fairfield, Suisun City, and Vallejo. The Permittees are required to report on their TMDL implementation actions annually. Follow the links below to view the MRP and the Permittees’ Annual Reports.

• Municipal Regional Stormwater Permit (Final Order No. R2-2009-0074) See Provision C.9.
• FY 2009-2010 Annual Reports See sections on Provision C.9 and associated attachments

Links:

The following links are for your information and do not indicate an endorsement by the Regional Water Quality Control Board.


UP3 Project
The Urban Pesticide Pollution Prevention (UP3) Project fosters effective outreach and education and provides technical assistance for implementation of the Diazinon and Pesticide-Relate Toxicity in Bay Area Urban Creeks Water Quality Attainment Strategy and TMDL. The project is funded by a State Water Board grant to the San Francisco Estuary Project. For more information, visit www.up3project.org.

Interested in less-toxic ways to control home and garden pests? Fact sheets displayed at a local Bay Area hardware store (pictured at left) provide tips on less-toxic methods to control ants, aphids, cockroaches, fleas, and other pests. For online versions of these fact sheets, click here (Our Water Our World). Photo by: Gina Purin

Pesticide Regulation

• California Department of Pesticide Regulation
• U.S. EPA Office of Pesticide Programs

Pesticide Information

• Pesticide Action Network Pesticide Database
• EXTOXNET Pesticide Information Profiles

Integrated Pest Management & Less Toxic Alternatives

• Our Water Our World Program
• University of CA Statewide Integrated Pest Management Project
• Less Toxic Home & Garden (Central Costa County Sanitary District)
• Bio-Integral Resource Center

Water Quality Monitoring Information
SWAMP Toxicity Report – November, 2010. Summarizes nine years of toxicity testing data collected by the State Water Board’s Surface Water Ambient Monitoring Program (SWAMP) and partner programs.

Detections of Pyrethroid Insecticides in Surface Waters from Urban Areas of California, 1993-2010, Xuyang Zhang, Ph.D., California Department of Pesticide Regulation, Environmental Monitoring Branch. December 3, 2010.

For more information contact:

Jan O’Hara
Planning and TMDLs Division
1515 Clay Street, Suite 1400
Oakland, CA 94612
E-mail: johara@waterboards.ca.gov
Phone: 510-622-5681