SUMMARY

California. Water samples showed no detects of fenoxycarb, hydramethylnon, pyriproxyfen, dimethoate, and methidathion. Bifenthrin was detected at 0.122 and 0.307 parts per billion (ppb) from two commercial nursery sites. Toxicity was tested at San Diego Creek at Campus Drive, an integrated site. This site was significantly toxic (100 % mortality) to Ceriodaphnia dubia in the water collected. Toxicity may be attributed to chlorpyrifos that was above the LC50 for C. dubia. At a nursery site a filter strip and settling pond has been added to the drainage to mitigate offsite movement of insecticides and nitrates. At the time of this sampling, Canna had been planted throughout the filter strip. There was a general trend of declining concentrations of bifenthrin and chlorpyrifos as the water passed through the filter strip. SCOPE OF THIS MEMORANDUM This memorandum reports results of water sampling conducted by the Department of Pesticide Regulation (DPR), under interagency agreement with the California Department of Food and Agriculture (CDFA), for the Red Imported Fire Ant (RIFA) control project. Data included here are from the November 15 and 16, 2000 monitoring, and encompass results from both chemical analyses and aquatic biotoxicity testing. This memorandum summarizes results for bifenthrin