Organochlorine Compound Residues in Eggs of Broad Snouted Caimans (Caiman latirostris).

MUÑOZ DE TORO, MÓNICA; STOKER, CORA; GARCÍA, SR; ZAYAS, MARCELO; REPETTI, MR; GALOPPO, GH; BELDOMÉNICO, HR; LUQUE, ENRIQUE

Mérida (México)

Workshop; Interntional Forum EcoHealth 2008; 2008

National Institute of Public Health of Mexico

Background. Organochlorine compounds (OCCs), such as pesticides and polychlorinated biphenyls (PCBs), are persistent lipophilic chemicals identified as endocrine disrupter compounds (EDCs) that have broad-ranging effects on wildlife. Recently we reported high frequency and elevated concentrations of OCC residues in human samples from a littoral region in Argentina. OCCs levels were positive associated with freshwater fish consumption. Caiman latirostris inhabit wetlands throughout northeastern Argentina and due to their longevity and their position at the top of the food net have the potential to accumulate high concentrations of OCCs. Objective. The aim of this study was to estimate the residues of OCCs present in the eggs of Caiman latirostris. Materials and Methods. Twenty three caiman clutches were collected from wetlands surrounding Parana River tributaries, immediately after oviposition. The sites have either no history of agriculture or intensive crops. Two eggs by clutch were used to establish OCCs egg burden. Results. A high frequency of organochlorine residues and elevated concentrations were found in 89% of egg samples. OCCs most frequently found were: p,p´-DDE in 63%, oxychlordane in 46%, o,p-TDE in 15.2%, HCB, heptachlor, and o,p-DDT in 10.9%, heptachlor epoxide and endosulfan sulfate in 6.5% of the samples. PCBs were present in 50% of the samples. Of the 14 targeted PCBs congeners, BZ 28, 153, 138 and 180 were the most abundant. Concentrations of total PCBs and OCCs were different among nests collected in different sites, while the pattern of OCCs pesticides were similar between neighbouring nests. Eggs from nests collected in the area of intensive agriculture had the highest concentrations (∑PCBs═ 40.2±25.1 ng/g lipid and ∑pesticides═ 184±60.2 ng/g lipid). Moreover, endosulfan sulfate was present only in eggs from this site. Conclusions. Exposure of the developing embryo to EDCs in the detected concentrations could alter reproductive performance in adulthood and drastically interfere with population stability of this top predator.