Kidney lesions in pelagic seabirds with high tissue levels of cadmium and mercury

Abstract

Light and electron microscopic techniques were employed to examine the kidneys of three species of pelagic seabird which had high tissue cadmium and mercury levels. Direct examination and comparison with the kidneys of cadmium and mercury dosed starlings showed that the seabirds had patchy nephrotoxic kidney lesions. It was suggested that these lesions were due to natural exposure of the animals to high levels of metals, particularly cadmium through their diet. Pathological features included necrosis and degeneration of the proximal tubular epithelium together with the direct observation of obstruction of the more distal neprhon segments by necrotic cellular debris. Abnormalities of the glomerular podocytes and Bowman's capsule cells were also observed. There was a high degree of similarity between the type and distribution of kidney lesions in the seabirds and the laboratory metal dosed starlings. The significance of this kidney damage and its possible effects on the birds survival prospects are discussed.