2015 Volume 6 Issue 1 Pages 31-42
Zinc is one of the industrially important metals widely used as materials of such as plating and brass. In addition,zinc is one of the essential minerals which is necessary to keep human body healthy. On the other hand, intake of an excess amount of zinc would be toxic for organisms including human, thus the environmental standard is prescribed in Japan. In this study, we examined toxic effect of zinc chloride on medaka larvae. We found that LC50 of zinc on medaka larvae was 5.4 (5.2-5.7 95% CL) mg/L. Furthermore, we showed that sodium chloride and sodium dihydrogenphosphate reduced the toxicity, especially the effect of sodium dihydrogenphosphate was remarkable. Histological and proliferation defect were not detected even in the zinc-treated larvae. These results confirmed the fact that co-existing sodium salt affects the toxicity of zinc, and the effect varies depending on forms of the salts.In addition, it was revealed that the defects of the cells caused by zinc in culture system does not necessarily arise in living organisms treated with zinc.