Organochlorine contamination in anuran amphibians of an artificial lake in the semiarid midwest of Argentina.

Artificial water reservoirs are important for fauna in arid-semiarid regions, because they provide suitable habitats for species that depend on water, such as amphibians. Organochlorine pesticides (OCPs) are toxic, persistent compounds that tend to bioaccumulate and bioconcentrate. We evaluated contaminant levels in anurans from an artificial lake (Embalse La Florida) in a semiarid region of the Midwest Argentina. This lake is one of the few sources of permanent water in the area. OCPs were detected in all individuals. Levels ranged from 2.34 +/- 0.62 ng/g wet mass of heptachlors to 9.76 +/- 1.76 ng/g wet mass of hexachlorocyclohexanes. The distribution pattern of OCP was Sigma HCH > Sigma DDT > endosulfan > Sigma chlordane > metoxichlor > Sigma aldrin > Sigmaheptachlor. Contaminant levels in individuals were positively correlated with contaminant levels in the water. Burden differed between species, but not among sites differing in water contaminant levels. Results suggest that anurans may concentrate OCPs and thus provide an important source of exposure for amphibian predators. This study provides important information for potential risk assessment of amphibians in the region and contributes to our understanding of the extent of OCP contamination.