文摘
A pesticide survey of surface water was conducted in1989, 1990, and 1991 in Lawrence, Mississippi, Phillips,andJefferson counties in Arkansas to assess nonpoint sourcewater pollution. During these 3 years, 59-62 lake andriver/stream sites were sampled eight times and screened for17 pesticides commonly used in Arkansas. Pesticideswere extracted by solid-phase extraction (SPE) disks.Extractswere analyzed by gas chromatography-electron capturedetection (ECD) and high-performance liquidchromatography-UV detection (LCUV). Detections wereconfirmed by gas chromatography-mass spectroscopy(MS) or co-chromatography. The 256 detections duringthesurvey represented 14 pesticides. Metolachlor (25%oftotal detections), atrazine (22%), norflurazon (16%), andcyanazine (14%) were the most commonly detectedcompounds. A total of 5% of the total detections wasabovehealth advisories. Spring and summer samples provided73% of the total pesticide detections. Rivers andstreamswere responsible for 62% of the detections. Thehighestnumber of repeated detections of the same pesticide at asite was for cyanazine (six of eight sampling periods).