Occurrence of organochlorine compounds in fish from freshwater environments of the central Andes, Argentina.

Abstract

The Central Andes region is considered an area of high environmental relevance in South America and it is rich in glaciers, which are the main fresh water sources and reservoirs of the region. The presence of organochlorine compounds (OCs) is an environmental threat due to their persistence and adverse effects on wildlife and humans. The levels of OCs, such as chlordane compounds (CHLs), dichlorodiphenyltrichloroethane and metabolites (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), and polychlorinated biphenyls (PCBs), were determined in muscle and liver tissues of fish and in sediments collected from different sites of the central Andes: the Mendoza River and the Yaucha River (rainbow trout: Oncorhynchus mykiss) and Carrizal Dam (silverside: Odontesthes bonariensis). Regardless of studied site and fish tissue, the general OC trend was: DDTs > PCBs > HCHs > CHLs > HCB. The results showed clear geographic distribution patterns for DDTs. Among the sampling sites, silverside fish showed the highest average load of DDTs (614 and 867 ng g-1 lw in muscle and liver tissues, respectively). Based on the biota-sediment bioaccumulation factor (BSAF), both rainbow trout and silverside fish showed comparable capability to accumulate p,p'-DDT in their tissues. Intraspecific correlational analysis showed that CB-138 in muscle and p,p'-DDT in liver were clearly correlated with the lipid content in silverside specimens, which highlights the relevance of taking into account the fat content and the type of target tissues.