Abstract
I evaluated the toxicity of polluted waters using sea urchin bioassays. The water samples tested showed inhibitory effects on the life cycle of sea urchins in the descending order of sensitivity of gametogenesis, sperm + egg, sperm, egg, metamorphosis, pluteus, gastrula, fertilization, cell division, blastula and adult . In most cases, sperm and eggs placed in the test water underwent fertilization and subsequent normal development. Abnormalities such as polyspermy (multi-polar division), permanent blastula, developmental delay, gastrula lacking the normal structure, spaceship Apollo-like gastrula, exogastrula, radialized embryo and others were identified in samples containing various heavy metals including zinc, nickel and others. Bioassay of samples taken over 34 years around Tanabe Bay, Wakayama Prefecture, Japan, showed the presence of marked pollution at some sites during the years 1970-1976 and 1982-1987. The former years may represent the normal degradation of pollution, whereas the latter may have been the result of TBT pollution arising from the use of anti-fouling paint for fishing cages and boats. Effluents from disused mines was also identified with this bioassay and chemical analysis. Various zinc-dependent and other abnormalities of development were observed.
