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Mallard ducks fed 2, 20, or 200 ppm cadmium chloride were sacrificed at 30, 60, and 90 d. No mortality occured during the study and body weights remained unchanged. Kidney weights of the 200-ppm group were significantly greater after 60 and 90 d than those of controls; also, testis weights were significantly lower after 90 d. Kidneys of ducks fed 2 and 20 ppm cadmium were relatively unaffected; however, slight to severe kidney lesions were found in the 200-ppm group after 60 d of treatment. No significant lesions were found in mallard testes after feeding 2 ppm cadmium in the diet, and only a few birds in the 20-ppm group showed slight to moderate gonad alterations. After 90 d of treatment, however, testes of males fed 200 ppm had atrophied and the spermatogenic process had ceased. This study should provide important information for the interpretation of cadmium levels found in kidneys and testes of wild ducks.

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Paired mallard ducks (Anas platyrhynchos) were given No. 4 lead shot, and bone lead concentrations were compared in drakes and in laying and nonlaying hens. Lead accumulation was significantly greater in bones with a high medullary content (femur and sternum) compared with bones with a lower medullary content (ulna-radius or wingbones). In dosed groups, hens always contained higher bone lead residues than drakes. After dosage with one shot (approximately 200 mg lead), lead in femurs of laying hens averaged 488.4 ppm compared with 113.6 ppm in nonlaying hens. Femurs of drakes averaged 9.4 ppm lead. Dosage with the second lead shot did not result in further accumulation of bone lead in hens, but increased bone lead concentrations threefold in drakes, suggesting that saturation levels for bone lead had already been reached in the hens after ingestion of one shot. There was no demonstrable relationship between egg production and bone lead residues. The high lead residues, found in medullary bones of laying hens indicate that sex and physiological condition are major factors influencing lead absorption by bone.