Marine pollution bioassay by using sea urchin eggs in the Tanabe Bay, Wakayama Prefecture, Japan, 1970–1987

Abstract The results of 18 years bioassays of the water at the Seto Marine Biological Lavoratory and around the Hatakejima island, Shirahama, Wakayama Pref., was shown according to the methods of Kobayashi's. During 1982 and 1987, very polluted water (Grade 3–5)was observed around Hatakejima island and Tsunashirazu cove in early autumn to winter. As these phenomena differed from the tendency of polluted water observed mainly in summer of each year, the presence of very polluted water mass was suggested at that time, such as containing tributyltin oxide(TBTO).