Mussel Watch: a review of Cu and other metals in various marine organisms in Taiwan, 1991–98

This study presents the distribution of Cu, Zn, Pb, Cd, Hg and As in various marine organisms collected along the western coast of Taiwan from 1991 to 1998, and also evaluates the time variation of Cu in oysters before (1980–85) and after (1986–98) the “green oyster” incident. The results show that relatively high geometric mean (GM) concentrations of Cu, Zn, Pb, Cd, As and Hg were generally found in Crassostrea gigas (Cu=229 μg/g, Zn=783 μg/g), Gomphina aeguialtera (Pb=30.3 μg/g), Tegillarca granosa (Cd=2.85 μg/g), Thais clavigera (As=96.9 μg/g) and Parapenaeopsis cornuta (Hg=1.35 μg/g), respectively. Especially, maximum Cu and Zn concentrations (GM=229 and 783 μg/g, respectively) in oysters (C. gigas) from different culture areas were much higher than those of the other organisms by about 1.13–458 and 2.40–63.7 times, respectively. Similarly, rock-shells (Thais clavigera) had a high capacity for accumulating Cu (GM=202 μg/g) and Zn (GM=326 μg/g) under the same physico-chemical conditions. The highest GM Cu and Zn concentrations of 1108 (range from 113 to 2806) and 1567 (range from 303 to 3593) μg/g were obtained in oysters from the Hsiangshan coastal area, one of the most important oyster culture areas in Taiwan. However, the highest GM Cd and As concentrations of 6.82 and 19.3 μg/g were found in oysters from the Machu Islands. Mean Cu concentrations in the oysters from the Erhjin Chi estuary declined from 2194±212 μg/g in 1986–90 to 545 μg/g (GM) in 1991–96. In the Hsiganshan area, GM Cu concentrations of 909 μg/g (1991–96) and 1351 μg/g (1997–98) in oysters were significantly higher than those of 201 μg/g (1980–85) and 682 μg/g (1986–90). The gradually increasing levels of Cu and Zn in the oysters from the Hsiangshan area have been observed year by year.