Abstract
We evaluated the toxicity and anti-estrogenic effects of menadion which is used for the ships ballast tank water treatment as broad spectrum biocides for phytoplankton, bacteria and aquatic invertebrates even resting eggs, for male and female medaka. Menadion performed toxicity against both male and female medaka same toxicity level as against aquatic invertebrates, however this effect was disappeared by photo-decomposition. Compare with the estrogenic effects on male and female medaka, the effect was observed only male but not female medaka. When male medaka treated with photo-decomposition derivative of menadion in presence of estradiol, anti-estrogenic effect was observed. These results suggested estrogenic or anti-estrogenic action was depended on inherent estrogen concentration. Menadion has high acute toxicity for not only invertebrates but also medaka. In addition, menadione or its photo-decomposed derivative has estrogenic or anti-estrogenic effects on male medaka, we mentioned menadione treated ships ballast tank water carefully before it was wasted into surface water to protect the restricted sea surface ecosystem.
