In just the third week of monitoring, there has been a second series of exceedances. The thiobencarb monitoring results show performance goal exceedances of 1.8 parts per billion at the two northern drain sites – Butte Slough and Colusa Basin Drain 5. On the same date, we had an exceedance of 2.7 parts per billion at one of the two additional sites monitored by the Department of Pesticide Regulation.
These numbers were recorded at the third sampling event of the season held on May 23. We trigger the start of the monitoring season from surveying growers about planting dates, and coordination with county agricultural commissioners on the thiobencarb notices of intent. The monitoring season start was two weeks later than our traditional date on the last Tuesday in April.
We are following up with the Department of Pesticide Regulation on recommendations to the management practices.