This paper deals with the toxic effects of selenium uptakes in the tissues of marine fish. The selenium concentrations in skin
liver
muscle and gill of the fish were determined by PIXE technique. The enzyme levels in liver tissue were also measured and evaluated. The results showed that the 50% lethal dose was LD50=0.29 μg/g. The enzyme levels in fish died following the injection were found independent on the injected dose. The enzymes in surviving fish showed a gradual and complete recovery during the observation period. A very low Se uptake in muscle was found. The biological half lives of Se concentration in liver and gill were nearly identical
while the skin exhibited a half life 2.5 times greater.