PARENT SESSION
WP5 - Riverine Discharge of Contaminants to Coastal Systems
Chair: Standley, Laurel1, 1 109 I Chestnut Crossing Drive, Newark, DE
2:10 PM to 5:30 PM - Wednesday, 20 November 2002
Room Ballroom D
(609) Characterization of the Movement of Selected Pesticides in Surface Water from an Agricultural Area in South Florida .
Wilson, Patrick*,1, 1 University of Florida, Indian River Research and Education Center, Fort Pierce, FL, USA
ABSTRACT- The objective of this study was to characterize trends in movement of selected organophosphate, N-methylcarbamoyloxime, N-methylcarbamate, and metallic pesticides in Ten Mile Creek, a tributary creek that discharges into the North Fork of the St. Lucie River Aquatic Preserve, an Outstanding Florida Water body (OFW). This OFW ultimately discharges into the St. Lucie Estuary (SLE) and Indian River Lagoon (IRL). These water bodies are all very important to the local region. The head waters for Ten Mile Creek originate in a completely channelized drainage basin, dominated by citrus groves and pastures. Samples were taken at a discharge structure (the outlet for the headwaters) daily when water was flowing past the structure, and every-other-day when no water was flowing. Pesticides monitored for included: azinphos-methyl, chlorpyrifos, diazinon, dimethoate, ethion, fenamiphos, malathion, methidathion, aldicarb, Aldicarb sulfoxide, aldicarb sulfone, carbaryl, methomyl, and oxamyl. Aldicarb, aldicarb sulfone, and aldicarb sulfoxide were detected in 16, 30, and 14 samples out of a total of 280 samples analyzed. Methomyl was detected in one sample and oxamyl was never detected between April 4th and September 30, 2001. Ethion and diazinon was present in 19 and 2 of 332 consecutive samples, respectively, analyzed between February 12, 2001 and February 12, 2002. No other organophosphate pesticides were detected. Detections of the more restricted pesticides coincided with periods when they are usually applied. Copper concentrations peaked during the summer months when discharge was greatest. Results indicate that monitoring programs for pesticides should target use periods. Results also indicate that intensive sampling is needed in flashy systems such as in South Florida (due to the prevalence of drainage canals) to better characterize pesticide exposure patterns.
Key words: carbamate, carbamoyloxime, copper, discharge