This case study shows that Orido Bay(wood pool)and Shimizu Port play an important role as buffer areas in
preventing diffusion of pollutants to Suruga Bay（the Pacific Ocean).Orido Bay is located within the inner part of
Shimizu Port and has a very narrow mouth with breakwaters. The suspended solids from the rivers that retain
various pollutants,such as heavy metals,are settled on the bottom of the bay.Anaerobic conditions developed there
promote production of hydrogen sulfide and subsequent sulfides with metals. The results show that the metal
concentrations are relatively high in the sediments from Orido Bay and that they decrease with distance from the bay
toward the outside of Shimizu Port.Near the entrance of the port,the concentrations of metals in sediments are in
accordance with their background values.