Transport of sediment-bound organochlorine pesticides to the San Joaquin River, California

摘要: Suspended sediment samples were collected in westside tributaries and the main stem of San Joaquin River, California, June 1994 during irrigation season January 1995 a winter storm. These analyzed for 15 organochlorine pesticides to determine their occurrence concentrations on suspended compare transport (April September) storm runoff (October March). Ten detected runoff; seven season. The most frequently both sampling periods p,p'-DDE, p,p'-DDT, p,p'-DDD, dieldrin, toxaphene, chlordane. Dissolved three Most calculated total chlordane, toxaphene exceeded chronic criteria protection freshwater aquatic life. At eight sites common between periods, streamflow greater - median concentration 3,590 mg/L versus 489 162 ft 3 /s 11 /s. Median DDT (sum p,p'-DDT), slightly season, but instantaneous loads at time substantially Estimated entire estimated by about 2 4 times transport. However, because mean annual is than storm, may be similar This conclusion tentative primarily insufficient information long-term seasonal variations concentrations. Nevertheless, from infrequent storms will continue deliver significant load sediment-bound qrganochlorine River even if irrigation-induced reduced. As result, biota relatively high compared other regions United States.