No abstract

In order to understand the factors causing variation of lead and cadmium accumulation in tissues of feral pigeons in Seoul and Ansan, Korea, we investigated their age, food items (crop and gizzard contents) as well as environmental factors such as soil, atmosphere, and local traffic density. The results indicate that concentrations of Pb and Cd were highly increased in the order of eggs < chicks < adults. In food analysis, supplementary foods (rice, small stones, domestic scraps, cements, hairs, Styrofoam, etc.) could be considered as factors considering the Pb concentration differences. Concentrations of Cd in foodstuffs, the proportion of crop contents as their major foods could have an influence on the difference of Cd levels from a nutritional viewpoint. The Pb levels in gizzard contents and soil had an effect on the tissue accumulations, these were associated with the volume of vehicular traffic. However, we could not find any differences of Cd concentrations in gizzard contents and soil, although there were significantly different Cd accumulations in target organs of adult pigeons between the study areas. The Pb and Cd levels in tissues did not correspond to atmospheric metal levels.

Globally threatened Cinereous vultures (Aegypius monachus) regularly over-winter in South Korea, and they have frequently been found dead in their natural habitats. As one possible factor for their mortality, we investigated tissues for heavy metal contaminants along with necropsies on 20 dead Cinereous vultures. Severe emaciation was found in the survey, being associated with 19 of the deaths. Two of the 19 showed lesions suggestive of lead poisoning in the tissues; there was no indication of trauma, embedded shot, lead bullets in the stomach, or signs of electrocution in the specimens. Of 20 vultures, two showed lesions compatible with death from lead poisoning with 19.7 ppm dry weight (6.9 ppm wet weight) and 34.1 ppm dry weight (11.1 ppm wet weight), and 14 individuals had a potentially toxic level of lead with >6 ppm dry weight (about 2 ppm wet weight) in liver or kidney. The ingestion of lead-contaminated carcasses probably occurs along their migratory route. The possibility of lead exposure from the breeding site (Mongolia) or stopover area (China) should also be considered because some individuals are likely to die at or upon arrival. Our results suggest that most of the dead Cinereous vultures may be suffering from abnormally high lead exposure, indicating a potentially important cause of mortality in this endangered species.

No abstract

This study presents concentrations of heavy metals in tissues of Black-crowned night herons (Nycticorax nycticorax), age-related variations related to the growth stage from chicks to adults, and comparison of concentrations between chicks and adults. Heavy metal differences by growth stage from chicks to adults were observed for iron concentrations in the muscle; manganese concentrations in the kidney; zinc and copper concentrations in the muscle; lead concentrations in the liver, kidney, and bone; and cadmium concentrations in the kidney. Comparing chicks with adults, iron concentrations in the kidney and bone of adults were higher than those of chicks. Copper concentrations in the muscle of adults were higher than those of chicks. Lead concentrations in the liver and bone were lower in adults than in chicks. Manganese, zinc and cadmium concentration of each tissue did not significantly differ between adults and chicks. We suggest that concentrations of iron, manganese, zinc and copper varied with the metabolic turnover for growth of chicks. In this study, lead concentrations of adults and cadmium concentrations of chicks and adults were within the range of background levels for wild birds, only lead concentrations of chicks were within the range of a level consistent with elevated lead exposure.