Kenshi Kimura

STUDY ON BIOACCUMULATION OF TRACE METALS IN SESSILE ANIMALSIN SHIMIZU PORT SEAWALL

The Port of Shimizu consists of semi-closed estuaries, and the heavy metal content of its water is higher than in open sea water. This contaminant presumably flowed into the harbor where it accumulated in the past. Recovering these contaminants would be extremely costly and energy-intensive, so it is not realistic. So this study examined a method of recovering this contaminant through bioaccumulation by the food chain. The state of sessile animal was investigated and the change over time of the amount of heavy metals accumulated in oysters and mussels that are the dominant species in the Port of Shimizu was surveyed, to set the appropriate recovery time for these sessile animals. They accumulate trace metals in a higher density than in the sea water within the port. Moreover, the sessile animals within the Port of Shimizu port die in larger numbers than during the summer. Therefore, it was assumed that the most appropriate recovery time is the spring season before the sessile animals die, regardless of the amount of trace metals accumulated in their tissue.