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
(610) Agrochemical inputs from Florida canals to the Biscayne Bay.
Harman-Fetcho, Jennifer*,1, Hapeman, Cathleen1, McConnell, Laura1, Potter, Thomas2, Rice, Clifford1, Bialek, Krystyna1, Schaffer, Bruce3, 1 Environmental Quality Laboratory, USDA/ARS, Beltsville, Maryland, US2 Southeast Watershed Research Laboratory, USDA/ARS, Tifton, Georgia, US3 Tropical Research and Education Center, University of Florida, Homestead, Florida, US
ABSTRACT- Significant declines in ecosystem health of the Biscayne and Florida Bays have been reported in the past decade and include: die-off of seagrass beds, declines in sponge, coral and shellfish populations and development of noxious algal blooms. Nearly 10 million pounds of inventoried agrochemicals are used in the South Atlantic estuarine drainage area. Previous studies have indicated the presence of endosulfan in surface water samples collected in the Florida Bay. Endosulfan is used by vegetable growers in nearby Miami-Dade County and is highly toxic to aquatic organisms. Atrazine, used extensively in sugar cane production in the West Palm Beach-Lake Okeechobee, has been detected in weekly, integrated rain samples collected in this area. An exploratory project was been initiated in South Florida to assess the impact of intense agricultural production on air and water resources of the South Florida sensitive coastal ecosystems. Rain and air were collected over the Fall 2001/Spring 2002 growing season in Homestead, Florida at the University of Florida, Tropical Research and Education Center. Rain was collected on an event-basis and extracted on-line using solid-phase extraction cartridges. Air samples were obtained weekly using a high volume sampler with a glass-fiber filter followed by polyurethane foam plugs. Surface water samples were collected from the Mowery Canal, surrounding agricultural areas and in the Biscayne Bay. All samples were analyzed by GC-MS in electron impact and negative chemical ionization modes. Concentrations of the currently-used pesticides, trifluralin, chlorpyrifos, malathion and endosulfan, in the surface water samples ranged from 0.1 to 0.7, 0.3 to 0.9, <0.2 to 0.6, 0.2 to 1.7 ng/L, respectively. Atrazine, hydroxyatrazine, alachlor, metachlor, and metolachlor ethane sulfonic acid were also detected in surface water samples. Agrochemical residues in surface water may be due to direct field runoff or atmospheric deposition.
Key words: Florida, ecosystem, Biscayne, pesticide