Survey of Dioxin and Furan Compounds in Sediments of Florida Panhandle Bay Systems.
Jon M. Hemming Michael Brim Robert Jarvis
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A sediment quality survey was conducted in the Florida Panhandle (Panhandle) over a period of 10 years (1992 to 2001). The survey examined which dioxin and furan compounds may be present in sediments of the bay systems, their locations, and concentrations. The U.S. Fish and Wildlife Service (FWS) collected and analyzed 29 sediment samples from 6 bay systems across the Panhandle. Risk associated with dioxin and furan contamination was estimated after 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity equivalents (TEQs) were calculated for 17 dioxin/furan chemical analytes as per the U.S. Environmental Protection Agency (1989). Total dioxin TEQ sediment concentrations ranged from 0.51ng/kg dry weight in Apalachicola Bay to 77.51 ng/kg dry weight in sediments from the Perdido Bay system. Pulp and paper processing facilities were near sampling locations where TEQ concentrations were over 20 ng/kg dry weight with the exception of one site in the Pensacola Bay system. Overall, the concentrations of dioxin TEQs in sediments of Panhandle bay systems were relatively low compared to similar surveys in the Great Lakes area and other bay systems worldwide. However, even sediment dioxin levels in the low range have been associated with biomagnification in the food web that increases risk to birds, fish, and sensitive mammal species. Additionally, there may be a relationship between the volume of freshwater input or the depth and width of Gulf of Mexico (Gulf) to bay passages (inlets) that influences dioxin TEQ concentrations in bay system sediments. The foremost goal of this survey was to provide baseline data necessary to evaluate the current status of, and future research needs for, the protection of fish and wildlife species, especially Federally threatened and endangered species, migratory birds, and anadromous fish. The next step in the evaluation of the bay systems of the Panhandle will be to examine food web effects such as biomagnification, dioxin compound affinity for organic carbon substrates, freshwater input effects, Gulf flushing influence, sediment contamination trends, and current or pending dioxin compound input sources to the bay systems. The relationship between sediment dioxin TEQ concentrations and risk to FWS trust resources can be inferred, but has not been established. Investigation into relationships between contaminated sediments, food fishes, and piscivorous fish and bird species may determine risk to FWS trust resources in the bay systems of the Florida Panhandle.
U.S. Fish and Wildlife Service
http://www.fws.gov/contaminants/Documents/FinalDioxinReport2.pdf, 1 MB
U.S. Fish and Wildlife Service - Panama City Ecological Services and Fishery Resource Office