PARENT SESSION
PS15 - Riverine Discharge of Contaminants to Coastal Systems
Sunday, 17 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P143) Occurrence and spatial distribution of inorganic and organic contaminants in coastal areas of Southwest Florida.
Alvarez-Fraga, Loreta*,1, Cejas, Mark2, Cai, Yong1, Gardinali, Piero1, 1 Florida International University, Department of Chemsitry / SERC, Miami, Florida, USA2 Florida International University, Department of Environmental Studies, Miami, Florida, USA
ABSTRACT- The research focus on the occurrence and distribution of various organic and inorganic pollutants in sediments from Naples Bay, Rookery Bay, Ten Thousand Islands and other locations along Southwestern Florida. For the last decade Naples Bay has been subject to increased anthropogenic inputs due to land development on the adjacent city. On the other hand, Rookery Bay and Ten-Thousand Islands are heavily protected pristine zones composed of mangrove forests, islands, salt marshes serving as nursing areas for a wide variety of wildlife. The main goal of the study was to assess the impacts of land use changes in the anthropogenic inputs to the coastal zones. Environmental concentrations of a suite of contaminants were determined as follows. Minor elements including Be, V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Sb, Pb, Sn, Se and Hg were assessed by ICPMS, GFAA, or AFS. Al was used to normalize the trace metal data for natural abundances. Polychlorinated Biphenyls (PCBs) and other organo-chlorinated pesticides such as DDT and its metabolites were analyzed using GC-ECD. PAHs, including extended their alkylated homologs, were analyzed by GC/MS-SIM and used as markers of different sources of pollution. Among the trace metals, concentrations of vanadium, chromium, copper and zinc showed enrichement over the crustal abundance signature with concentrations ranging from 2.16 to 49.44 ng/g. DDE (p,p- isomer) was the chlorinated compound more often detected in the sediment samples at concentrations ranging from non detected to 1.42 ng/g. Other chlorinated pesticides such as aldrin, chlorpyrifos, and mirex were also detected but the frequency of detection was small with most levels close to the MDL to a maximum of 4.21 ng/g. PCBs where also detected but often as random hits for non specific congeners rather than a pattern of Aroclor contamination. The abundance of total PAHs (0.5 to 908 ng/g) showed a much more defined distribution trend and higher concentrations where observed in the north portions of Naples Bay, the Chocohatchee River and several heavily transited waterways. Despite the occurrence of these contaminants, large portions of the surveyed area remain in relatively pristine condition when compared with other urban coastal environments within the state of Florida.
Key words: Southwest Florida, Metals, PCBs, Pesticides, PAHs, Sediments