Mj. Portelli et al., Effect of dichlorodiphenyltrichloroethane on sex determination of the common snapping turtle (Chelydra serpentina serpentina), ECOTOX ENV, 43(3), 1999, pp. 284-291
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.