Organochlorine Pesticides (OCPs) are persistent and lypophilic compounds that bioaccumulate and biomagnify throughout the food web. Marine mammals, such as Sotalia guianensis (Guiana Dolphin), are vulnerable to these contaminants, since they occupy the top level of the food web in marine ecosystems. We determined OCPs concentrations in S. guianensis (n=18) found stranded or incidentally caught in fishing nets along the northern coast of Rio de Janeiro. Sample extraction of muscle tissue consisted of extraction, clean-up and chromatographic analysis. The pesticides analyzed by gas chromatography with an electron capture detector (GC-ECD) were DDTs, CHLs, HCHs, Drins, HCB and Mirex. Results show that p-p�-DDE was the predominant compound in both species. Only HCB, ?-HCH, Mirex and DDTs were above the method limit of quantification. HCB concentrations were similar in all sampling years, while?-HCHshowed higher values for n=1 in 2004. All o,p�-DDE were in the same order of magnitude, while  p,p�-DDE showed higher concentrations values in 2003 (n=1) and 2011 (n=4). o,p�-DDD on the other hand was higher in 2004 (n=1), and showed very low values in 2003 (n=1). p,p�-DDT and  o,p�-DDT were higher in 2011 (n=4) and mirex was higher in 2011 (n=4). OCPs levels in the present study are considered high in comparison to other studies and levels reflect the large amounts used in Brazil and their persistence in the environment. DDE were the main products found in this study, which may be related to the degradation of DDT, widely used in 1970 and early 1980s. High concentrations of Mirex were also found, used as both a pesticide and flame retardant. The variability of the results can be related to several facts, such as age, non-specific diet and sampling year, as well as varying contamination sources in this species habitat on the northern coast of Rio de Janeiro.

Contamination by chlorinated pesticides in Guiana dolphins from the Brazilian southeastern coast

248th National Meeting (2014)

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