Here’s a link to a new blog from Bruce Linquist, UC Cooperative Extension Specialist.
Bruce covers three scenarios that may arise, following this month’s heavy rainfall during rice planting.
Thiobencarb exceeded the 1.5 µg/L (parts per million) performance goal to a reading of 2.3 µg/L at the Colusa Basin Drain 5 (CBD5) site off Highway 20. A monitoring site receiving drainage from Colusa and Glenn Counties. This particular exceedance was at the second monitoring event on May 14.
Pyrethroid insecticides have been under scrutiny for several years resulting in recent changes to water quality requirements. The changes set monitoring levels for pyrethroids at nanograms in surface waters. Consistent exceedances of the levels could result in additional restrictions to pyrethroid use, or designate a drain as impaired with future restoration to correct the water quality. Last year, one of the water quality coalitions had a detection that could be problematic under the new standards.