Abstract
Lyophilized and powdered oyster meat was extracted with acetone, and the residue was extracted further with 0.5 M NaCl. The NaCl-soluble fraction was dialyzed against the same NaCl solution. The heavy metal content in each sample (samples A-G) was determined by atomic absorption spectroscopy, and an aliquot of the NaCl-soluble fraction was chromatographed over Sephadex G-50. 1) Acetone failed to extract 99% of Zn, Cd, and Cu in the freeze-dried oyster meat while 35% of Zn, 16% of Cd, and 41% of Cu in the acetone-insoluble fraction (fraction C) were extracted with 0.5 M NaCl solution, and 91% of Zn, 82% of Cd, and 78% of Cu in the NaCl-soluble fraction (fraction D) were dialyzed. 2) Heavy metals in fraction D appeared in two peaks of high and low molecular fractions in Sephadex gel filtration chromatography. Heavy metals in the high molecular fraction were not dissociated and were not dialyzed in 0.5 M NaCl solution. 3) When the oyster was bred in an artificial sea water containing various concentrations of Cd, the content of Cd in oyster meat increased in proportion to the concentration of Cd in artificial sea water. On the other hand, the content of Zn in oyster meat decreased with the increase of Cd in artificial sea water. 4) Accumulation of Cd in oyster meat did not decrease for 1 week after immersion of oyster in natural sea water.
