Concentrations, transport and biological effects of dormant spray pesticides in the San Francisco Estuary, California

摘要: The transport and biological effects of dormant spray pesticides were examined in the San Francisco Estuary, California, by measuring dissolved-pesticide concentrations estimating toxicity using bioassays at a series sites January February 1993. Distinct pulses pesticides, including diazinon, methidathion, chlorpyrifos, detected Joaquin River Sacramento following rainfall. higher pesticide loads compared with those can be attributed to greater amount rainfall Valley. use patterns water solubility account for observed temporal spatial distributions two rivers. followed through northern embayment Estuary. In contrast, distribution Sacramento-San Delta changed from distinct steady increases concentration over time. Seven-day indicated that Rio Vista was acutely toxic Ceriodaphnia dubia (water flea) 3 consecutive d Vernalis 12 d. These samples all had highest diazinon concentrations. Examination 96-h LC50 values (lethal kills 50% test organisms 96 H) indicates measured could most but not toxicity. Other present contribute