Atrazine is a widely used pre-emergent herbicide for controlling broadleaf plants. Since atrazine (a known endocrine disrupting chemical) is applied in the late spring and early summer, its impact on turtles nesting in water-saturated sandbars during this time is very relevant. To examine this possible impact of atrazine on development, behavior, and growth, eggs were obtained from 10 nests of two closely related map turtles, Graptemys ouachitensis and G. pseudogeographica. Two eggs from each nest were incubated in sand treated one time with atrazine in one of four concentrations of the herbicide (control, 0.1ug/L, 10ug/L, 100ug/L) based on levels measured in the river adjacent to the site where eggs were collected. Hatching success, incubation length, external morphological abnormalities, three measures of body size (mass, carapace length, and plastron length), righting speed, and swimming speed were recorded for all turtles. Half of the hatchlings were sacrificed to determine the sex from gross gonadal inspection. The remaining neonates were reared individually for 10 mo during which time nest escape behavior, time to first foraging event, foraging speed, growth, and survival were evaluated. 

Results/Conclusions

None of the variables recorded at hatching was affected by atrazine treatment. However, turtles deriving from atrazine-treated eggs had a significantly lower success in several of the long-term behavior trials, such as eating ability, time to first consumption, and escape. These findings reveal persistent fitness-reducing impacts on neonatal turtles of atrazine exposure during embryonic development, providing a new perspective on herbicide management.