Organochlorine pesticides and PCBs in a southern Atlantic coastal lagoon watershed, Argentina.

There recently have been increasing interest in South America on organic pollutants from the coastal marine environment. This study intended to seek out the occurrence and distribution of persistent organochlorine compounds in the Mar Chiquita coastal lagoon watershed. The levels were measured in sediments and associated crabs. Though a significant number of PCBs (mainly penta- and hexachlorinated congeners) were detected, the concentrations were very low (in the order of ppbs), indicative of an estuarine environment with little industrial development. On the other hand, pesticide residues were higher than PCBs in one or two orders of magnitude, as a result of the important agricultural activities in the area. Heptachlor epoxide, DDT and its metabolites, and gamma-HCH were the predominant OC pesticides in sediments as well as in crabs. Significant differences among geographical areas: Channel 5 and Vivoratá Creek (northern and southern sampling sites, respectively) contained detectable pesticide concentrations (heptachlor epoxide, DDE, DDD, and mirex).