Water Quality

Water Quality •

Is this the Last Year for Thiobencarb?

The question frequently comes up if this is the last year for thiobencarb use in rice. The answer now is…maybe. For the first time since the CRC took over management from the Department of Pesticide Regulation (DPR) in 2003, the program received a conditional approval after eight exceedances of the performance goal in 2019. 

Please keep a copy of the DPR thiobencarb permit conditions available for reference: 

The permit conditions provide water holding requirements and drift minimization from water ways. 

What does conditional approval mean?

Rice growers will have use of thiobencarb for 2020. The CRC is required to provide additional assessment in the annual report to the Central Valley Water Board by December 31. The assessment should identify additional management practices, either broadly or geographically, for meeting compliance with the 1.5 ppb performance goal in the drains starting in 2021.

What if additional management practices cannot be identified?

The Central Valley Water Board implements a prohibition of discharge. The requirement can either be broad or geographic and the terminology means no thiobencarb can legally be discharged (released) from the field. 

What about the water holding requirements?

Unfortunately, compliance by the county agricultural commissioners through the DPR Enforcement Office would no longer apply under a prohibition of discharge. Rice growers would be subject to fines levied by the Central Valley Water Board. The fines estimate gallons of discharge and apply penalties up to several thousand dollars per day. 

Are other options available?

The Central Valley Water Board identified the voluntary acreage limitations, which were lifted in 1994. Acreage limitations would have to be implemented through voluntary production caps. The previous limitations allowed production of enough formulated product to treat 110,000 acres with Bolero and 30,000 acres with Abolish for a total of 140,000 acres. 

For more information, contact the CRC’s Industry Affairs Manager Roberta Firoved at rfiroved@calrice.org or (916) 206-5039.

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Rice Water Quality Programs Monitoring Update
Water Quality •

Rice Water Quality Programs Monitoring Update

Monitoring for 2025 is halfway complete.

The 2025 surface water monitoring under the RPP and WDR programs is ongoing.

For the Rice Pesticide Program (RPP), there have been a handful of detections in late May, none of which were above the agricultural drain performance goal.  The latest results from early June were non-detectable.  

The Rice Waste Discharge Requirements (WDR) surface water program is in an assessment year, which means additional sampling for pesticides and toxicity.

Pyrethroids used in rice have been reported in association with water toxicity at the upper Colusa Basin Drain this year for multiple events.  The California Rice Commission (CRC) sent out letters earlier this year requesting the use reporting information (to be submitted in the fall) for pyrethroid users in the area.  Algal water toxicity was reported in the Sacramento Slough near Karnak as well.  

The CRC continues to work on behalf of the industry to conduct required monitoring and interface in reporting with the Water Board.  Additional efforts are underway to assess and analyze water quality trends across the valley and gather information from industry on uses and operational patterns.

We appreciate the industry’s support of the regulatory programs and their good stewardship of the commercial products used and protection of the environment.

For more information, contact the CRC’s Industry Affairs Manager Craig Riddle at criddle@calrice.org.