Effect of dichlorodiphenyltrichloroethane on sex determination of the common snapping turtle (Chelydra serpentina serpentina)

Recent evidence indicates that 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethan e (DT) and some of its metabolites alter reproductive and endocrine functio n in wildlife. Exposure to such endocrine-disrupting compounds during embry onic development can affect sexual differentiation. The authors tested the hypothesis that dichlorodiphenyltrichloroethane (p,p'-DDE) causes feminizat ion of the common snapping turtle (Chelydra s. serpentina), a species with temperature-dependent sex determination, during embryonic development. Eggs from eight clutches (total eggs tested = 237) were incubated at a male-pro ducing temperature (26 degrees C). At stage 14 of embryonic development, p, p'-DDE was applied topically at four concentrations and estrogen (estradiol -17 beta) was applied as a positive control. Although application of estrog en did induce female development at this temperature, application of p,p'-D DE did not affect sex determination at the exposure levels used. Residue an alysis indicated that the amount of p,p'-DDE detected in the eggs 72 h afte r application was considerably less than the concentrations applied. Howeve r, the amounts that penetrated the shells mere comparable to levels which h ave been found in moderately contaminated sites in the Great Lakes. These r esults indicate that p,p'-DDE, at levels that exist in the environment in t he Great Lakes, does not cause the feminization of snapping turtles during embryonic development. (C) 1999 Academic Press.