Effects of Selenium, Mercury, and Boron on Waterbird Egg Hatchability at Stillwater, Malheur, Seedskadee, Ouray, and Benton Lake National Wildlife Refuges and Surrounding Vicinities.

摘要

This project is being conducted to evaluate selenium, mercury, organochlorine pesticides, and boron concentrations in eggs in relation to egg hatchability and deformities. Ducks, coots, black-necked stilts, eared grebes, and white-faced ibis are being examined. Eggs and birds are being collected from several National Wildlife Refuges in the western US. These locations were associated with agricultural lands with return irrigation drainwater flowing into the refuges. We reasoned that concentrations of drainwater pollutants (selenium and boron) and mercury in eggs, hatching success, and incidence of deformities would provide useful information for evaluating potential adverse effects of these trace elements on nesting waterbirds. A sample egg was collected from each nest for chemical analysis, the success of the remaining eggs in each clutch was monitored, and the incidence of deformities was recorded. Our concept was to attempt to relate the success or failure of the eggs in the nest to contaminants in the egg collected from that nest. Because, predators depredated a high percentage of the duck nests, duck eggs were placed in an artificial incubator to hatch them. This approach eliminated the adverse effects of predation and the highly variable habitat conditions. Nests of the other species continued to be studied under field conditions. The frequency distributions of egg residue concentrations collected in this study were presented and compared to critical concentrations from the literature for a hazard assessment. The incidence of deformities as well as the hatchability data from the duck eggs placed in the incubator and the hatching success of natural nests were also used in the hazard assessment.