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Transport of Diazinon and Chlorpyrifos in the Lower San Joaquin River Basin

Project Chief: Charlie Kratzer

Diazinon and chlorpyrifos are a concern to the State Water Resources Control Board (SWRCB) and the U.S. Environmental Protection Agency (USEPA) as a possible source of toxicity in the San Joaquin River (SJR) and the Sacramento-San Joaquin Delta, especially during storm events following the application of dormant spray. The SWRCB has listed the lower SJR and several tributaries as impaired water bodies based on diazinon and chlorpyrifos on the 1998 California 303(d) list approved by USEPA in May 1999. Of these listings, some are identified as high priority for development of Total Maximum Daily Loads. These include the lower San Joaquin and Merced Rivers for diazinon and chlorpyrifos, and the Tuolumne and Stanislaus Rivers for diazinon only. Medium-to-low priority listings include Turlock Irrigation District lateral 5, Orestimba Creek, and Salt Slough for diazinon and chlorpyrifos.



Contact Information

Charlie Kratzer
Office phone: 916-278-3076

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