San Joaquin Valley 
Stormwater Quality Partnership



California Urban Pesticides and Toxicity Monitoring Data Report

11/25/2013 1:34 PM | Anonymous member (Administrator)

From: Geoff Brosseau []
Sent: Monday, November 25, 2013 8:23 AM
To: CASQA - Board 2013; CASQA - Executive Program Committee - 2013
Cc: Geoff Brosseau

Subject: California Urban Pesticides and Toxicity Monitoring Data Report

CASQA Board of Directors and Executive Program Committee,


The purpose of this email is to make sure you and your colleagues are aware CASQA recently published a report compiling monitoring data for two types of common, currently used pesticides: pyrethroids and fipronil.  The report summarizes thousands of samples from more than 100 urban surface waters throughout California.


The report documents widespread water and sediment toxicity in California urban waterways, with pyrethroid insecticides commonly identified as the apparent cause. Pyrethroids and their associated toxic effects have been found routinely in California urban areas, wherever monitoring is performed using technically appropriate protocols.


Fipronil--an alternative to the pyrethroids--also commonly occurs in California urban watersheds.  Observed concentrations of fipronil and its degradates are approaching and in some cases exceeding effect thresholds, suggesting an increasing potential for fipronil to pose risks to aquatic ecosystems.    


As many of you know, because California local agencies do not have the statutory authority to control pesticide uses, CASQA has partnered with California Water Boards to work with California Department of Pesticide Regulation (DPR) and EPA's Office of Pesticide Programs toward addressing this and other pesticide water pollution.  In 2012, DPR enacted regulations to reduce outdoor use of pyrethroids in an effort to end the pyrethroid water pollution documented in this report.  


This data compilation is being widely shared with pesticides regulators, water quality agencies, the pesticide industry, pest management professionals, and interested stakeholders with the intent of informing continuing management actions to address urban pesticide water pollution.  


The full report is available online at:    


Please share this with colleagues.  The following Subcommittee chairs should consider distributing this report to their members: Monitoring & Science; Phase II; Policy & Permitting; and Watershed Management and Impaired Waters.

CASQA has shared this report with EPA Office of Pesticide Programs, EPA Office of Water, EPA Region 9 (both water & pesticides), DPR, State & Regional Water Board pesticides liaisons (management and the staff that are partners in our joint pesticides regulatory effort), the Urban Pesticides Committee email list, the NPS Info, CWEA P3S, and various POTW listservers, various IPM and scientific researchers working in related areas, and colleagues in other states.


Thank you, 




Geoff Brosseau
Executive Director
California Stormwater Quality Association (CASQA)
P.O. Box 2105
Menlo Park, CA 94026-2105
650-366-1042 (Voicemail box only)

CASQA is a 501(c)(3) non-profit organization dedicated to the advancement of stormwater quality management, science, and regulation. 


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