Heavy metal concentrations in marine fishes collected from fish culture sites in Hong Kong

The levels of six heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) in different ti ssues of three species of cultured marine fishes (Epinephelus areolatus, Lu tjanus russelli, and Sparus sarba) collected from three fish culture sites in Hong Kong were evaluated. Metal pollution problems in the fish culture s ites were serious, as reflected by the high metal concentrations recorded i n sea water, sediments, and the biomonitor Perna viridis. In general, tissu es of all three species contained high concentrations of Zn and Cu, but muc h lower concentrations of Ni, Pb, Cd, and Cr. Similar pattern of heavy meta l concentrations was observed in sea water, sediment, and P. viridis. Metal concentrations in various tissues varied greatly among species and among f ish culture sites. Different tissues showed different capacity for accumula ting heavy metals. Gonad of all three species contained high concentrations of Zn. On the other hand, liver seemed to be the primary organ for Cu accu mulation. Overall, metal concentrations in the tissues of culture marine fi shes were much lower than those in P. viridis. Despite high metal levels in sea water and sediments, concentrations of Cd, Cr, and Pb in edible tissue s, including muscle and skin, did not exceed permissible levels recommended by the Hong Kong Government for human consumption.