An egg injection technique to evaluate the effect of polychlorinated biphenyls on the hatching success of the snapping turtle (Chelydra serpentina serpentina).

Embryos of oviparous organisms are exposed to contaminants by two pathways: contaminant uptake from the surrounding environment, and the transfer from female to offspring (maternal transfer). The initial source of contaminant exposure for most embryos is likely to be maternal transfer; therefore, maternal transfer studies are critical in determining the effects of contaminants on future populations. Injection of contaminants directly into eggs is one route of experimental contaminant exposure that permits controlled doses and potential reliable replication. This technique, however, has been used in the past with little success in reptiles. The objective of the present study was to evaluate egg injection as a means of mimicking maternal transfer of polychlorinated biphenyls (PCBs) to snapping turtle eggs. Eggs from several clutches were injected with a PCB solution and incubated at several temperatures and moisture levels to measure interactive effects of injection, environmental condition, and contaminant load on hatching success. The injection technique allowed for application of consistent and specific doses among replicates. Overall hatching success in this study was 61% and was as high as 71% within specific treatments. Hatching success was much higher in this study than in other studies using egg injections to mimic maternal transfer in chelonians and crocodilians.