Rimkus, T.A.*; Siebert, C.A.; Selby, D.M.: Lead analysis of snapping turtle (Chelydra serpentina) hatchlings exposed to lead nitrate at various times during incubation.

Eggs from three female snapping turtles were incubated in sand with a water content of 4% by mass. This is equivalent to being exposed to a water potential of -7 kPa. Three eggs from each female were exposed to lead nitrate for 48 hours on days 0, 15, 21, 30, 40, and 50 of incubation. A 0.01M lead nitrate solution was used to wet the sand to 4% water content. The eggs were then incubated in the absence of lead nitrate for the remainder of incubation. The hatchings were subsequently sacrificed and analyzed for lead. Hatchlings that were exposed to lead nitrate at the beginning of incubation had high levels of lead (1.54 ppm) while hatchlings that were incubated after day fifteen had lead levels (0.050 ppm) not significantly different from the controls (0.043 ppm). During the time of exposure to the lead nitrate, the eggs did take up water. These results support the hypothesis that egg water exchange during the later stages of incubation should be in the vapor phase, so as not to interfere with gas exchange.