Organochlorine compound residues in the eggs of broad-snouted caimans (Caiman latirostris) and its relationship with eggshell features and parameters of reproductive performance.

STOKER C; DURANDO M; GALOPPO GH; CANESINI G; COCITO L; LUQUE E H; MUÑOZ-DE-TORO M

Buenos Aires

Congreso; IV Congreso Argentino de la Sociedad de Toxicología y Química Ambiental SETAC Argentina; 2012

Organochlorine compounds (OCCs), like pesticides (OCPs) and polychlorinated biphenyls (PCBs), are persistent lipophilic chemicals that exhibit endocrine disrupting activity. Broad-snouted caiman (Caiman latirostris) is an oviparous species widely distributed in South America and have the potential to accumulate OCCs. Biomarkers can provide powerful tools as early warning signals of ecological damage. Exposure biomarkers are direct tissue residue analyses that contribute to theidentification of contaminants, whereas effect biomarkers are the organism responses to thesechemicals. The aims of this study were to evaluate and characterize biomarkers associated to OCCs exposure and their effects on C. latirostris. Recently, we reported the OCCs burden in caiman eggs from sites with different degrees of anthropogenic intervention. OCP residues were found in all clutches. The principal contributors to the OCPs burden were the DDT family and oxychlordane. PCBs were present in 93% of the clutches. Higher concentrations and higher diversity of pesticides, including endosulfan sulfate, were found in the eggs of the nests harvested close to croplands. A negative correlation was found between clutch size and sumOCCs, mainly due to the sumOCPs. Since egg OCC concentrations predict maternal burden, these findings suggest that higher OCCs exposure could lead to smaller clutches. Ongoing studies addresses the relationships between OCCs burden with eggshell features and parameters of clutch viability. A significant inverse correlation between eggshell porosity and OCCs burden, was found. Furthermore, a decrease in caimans survival with decreasing pores density, was observed. The presence of OCPs and PCBs in caiman eggs from the Paraná River tributary regions reveals their past and recent use. Caimans are long-lived and nonmigratory with a small home range. Consequently, caiman eggs could be a valuable tool to biomonitor local contamination. Moreover, OCCs could interfere with caiman population stability by affecting their reproductive performance and are a potential harm to the ecosystem health.