SPECIFIC ACCUMULATION OF MERCURY AND SELENIUM IN SEABIRDS

Total mercury (T-Hg), methyl mercury (MeHg) and selenium (Se) concentr ations were determined to elucidate the relationship between Hg and Se levels in the liver of 10 seabird species. Highest concentrations of T-Hg (mean 267 mu g/g dry wt), MeHg (mean 25.5 mu g/g dry wt) and Se ( mean 113 mu g/g dry wt) were in the liver of black-footed albatross (D iomedea nigripes). An equivalent molar ratio of 1:1 between T-Hg and S e was found in the liver of individuals which contain over 100 mu g Hg /g. However, such a relationship was unclear in other individuals whic h had relatively low Hg levels. This suggests that Se plays a sole in Hg detoxification for those individuals with high Hg. In seabird tissu es, Hg and Se levels should be a most important factor determining the relationship between Hg and Se, and fluctuation of Hg burden through molting and the species-specific demethylation capacity would also inf luence their relationships. (C) 1997 Elsevier Science Ltd.