Additional Pressure to a Threatened Species: High Persistent Organic Pollutant Concentrations in the Tropical Estuarine Batoid Gymnura altavela

Persistent organic pollutants (POPs) were determined in Gymnura altavela liver samples from one of the most impacted estuarine environments in the Atlantic Ocean (Guanabara Bay, Brazil). PCBs were the predominant compounds (91.2%) averaging 6773 +/- 4659 ng.g(-1) lipid weight (lw). DDT, Mirex, HCH and HCB concentrations were 633 +/- 715, 6.2 +/- 9.3, 3.4 +/- 1.4 and 0.5 +/- 0.5 ng.g(-1) lw, respectively. Recent DDT input in the estuary was minimum, as verified by the p,p '-DDE/ n-ary sumation DDT ratio (0.67). The prevalence of industrial compounds was highlighted by the sigma DDT/sigma PCB ratio (0.08). A negative correlation detected between disc width and PCBs, Mirex and HCH concentrations may be a consequence of maternal offloading. High POP concentrations in G. altavela liver samples from Guanabara Bay suggests that PCBs, in particular, may pressure the conservation of this threatened with extinction tropical estuarine batoid species.

Automated summary

Persistent organic pollutants (POPs), mainly PCBs, were found in Gymnura altavela liver samples from the highly impacted Guanabara Bay in the Atlantic Ocean, with high concentrations suggesting potential conservation pressure on the threatened batoid species. The prevalence of industrial compounds was highlighted by a low sigma DDT/sigma PCB ratio, indicating lower recent DDT input in the estuary. A negative correlation between disc width and concentrations of certain POPs suggests a potential impact of maternal offloading on the species.