ENVIRONMENTAL CONTAMINANTS IN NONVIABLE EGGS OF THE ENDANGERED MISSISSIPPI SANDHILL CRANE (GRUS-CANADENSIS PULLA)

Our objectives were to determine if concentrations of environmental po llutants and microbial contamination in nonviable eggs of the endanger ed Mississippi sandhill crane (Grus canadensis pulla) contributed to e gg failure. Six eggs collected in 1990 and four in 1991 contained only background levels of organochlorine pesticides and polychlorinated bi phenyls (PCBs), and tests for microbial contamination were all negativ e. Two eggs contained late dead embryos, but neither revealed obvious abnormalities. Three eggs contained potentially harmful concentrations (23, 39, 146 pg/g, wet mass) of polychlorinated dibenzo-p-dioxins (PC DDs) and dibenzofurans (PCDFs), based on 2,3,7,8-tetrachlorodibenzo-p- dioxin equivalents (TCDD-EQ) for combined compounds. Because of the sc arcity of material suitable for laboratory examination and the endange red status of the crane, we recommend that nonviable eggs continue to be monitored for toxic pollutants.