In September 2008, organotin (Ot) compounds were prohibited from being used worldwide. From 1997 onward in Japan, the production of paints containing TBT (tributylin) compounds was prohibited, and thus alternatives to Ot antifoulants have been used since then. It has been said that the decomposition characteristics of these materials are better than those of Ot compounds. The toxicity of alternative Ot antifoulants (e.g., diuron, irgarol 1051®, and Sea-Nine 211®) and Ot compounds (TBT and TPT (triphenyltin)), using oysters that inhabit a large area of Hiroshima Bay, were evaluated. The results showed that the toxicity of diuron and irgarol 1051 is very low, and the toxicity of Sea-Nine 211 is almost the same as that of TPT. Sea-Nine 211's effect was stronger on oysters than other shellfish, causing concern about the extent of Sea-Nine 211's impact on oyster development.

Accumulation of Ot alternative antifoulants in sediment is the focus of this research. Much research had been done on surface sediment, but in this report, the accumulation in the sediment core was studied. The Ot alternative antifoulants, Diuron, Sea-Nine211, and Irgarol 1051, and the latter’s degradation product, M1, were investigated in five samples from the northern part of Hiroshima Bay. Ot compounds (tributyltin (TBT) and triphenyltin (TPT)) were also investigated for comparison. In addition, metal (Pb, Cu, Zn, Fe and Mn) levels and chronology were measured to better understand what happens after accumulation on the sea floor. It was discovered that Ot alternative antifoulant accumulation characteristics in sediment were like Ot compounds, with the concentration in the sediment core being much higher than surface sediment. The concentration in sediment seems to have been affected by the regulation of Ot compounds in 1990, due to the concentration of Ot alternative antifoulants and Ot compounds at the survey point in front of the dock, showing an increase from almost the same layer after the regulation.

No abstract

Prohibition of Ot (organotin) compounds was introduced in Japan in 1997 and worldwide from September 2008. This meant that the production of paints containing TBT compounds was stopped and alternatives to the available Ot antifoulants had to be developed. It has been claimed that the degradation by-products of these alternative antifoulants were less toxic than those of Ot compounds. Since the introduction of the alternative antifoulants, the accumulation of these compounds has been reported in many countries. However, the toxicity of these compounds was still largely unreported. In this research, the toxicity of the alternative Ot antifoulants TPBP (triphenylborane pyridine) and TPBOA (triphenylborane octadecylamine) and their degradation products on Crassostea gigas and Hemicentrotus pulcherrimus were tested. The results showed that toxic effects in Crassostea gigas was higher for each antifouling biocide than that in Hemicentrotus pulcherrimus. Also, while the toxicity of the Organoboron antifoulants and the Ots were the same, the former’s degradation products were much less harmful.

［環境化学(J o u r n a lo fE n v i r o n me n t a lC h e mi s t r y)V o l. １ ８,No. １,p p. １ ９-２ ７, ２ ０ ０ ８］ 有機スズ代替船底防汚剤による 広島湾北部海域の底質汚染状況 常政 典貴 １) ，上野 博昭 ２) ，久保田明利 ２) ，岡村 秀雄 ３) １) 広島市環境局環境保全課(〒７ ３ ０-８ ５ ８ ６ 広島県広島市中区国泰寺町１-６-３ ４) ２) 広島市衛生研究所環境科学部(〒７ ３ ３-８ ６ ５ ０ 広島県広島市西区商工センター４-１-２) ３) 神戸大学海事科学部海洋環境管理研究室(〒６ ５ ８-０ ０ ２ ２ 兵庫県神戸市東灘区深江南５-１-１) ［平成１ ９年３月２ ９日受付，平成１ ９年１ ２月４日受理］ C o n t a mi n a t i o no fOr g a n o t i nAl t e r n a t i v eAn t i f o u l a n t s i nC o a s t a lS e d i me n to fHi r o s h i maBa y No r i t a k aT S UNE MA S A １) ,Hi r o a k iUE NO ２) ,A k i t o s h iK UB OT A ２) a n dHi d e oOK A MUR A ３) １) E n v i r o n me n t a lP l a n n i n gDi v i s i o nE n v i r o n me n t a lB e r e a uHi r o s h i maC i t yHa l l (１-６-３ ４ K o k u t a i j i ,Na k a ,Hi r o s h i ma ,Hi r o s h i ma７ ３ ０-８ ５ ８ ６) ２) Hi r o s h i maC i t yI n s t i t u t eo fP u b l i cHe a l t h (４-１-２ S h o u k o u s e n t a ,Ni s h i ,Hi r o s h i ma ,Hi r o s h i ma７ ３ ３-８ ６ ５ ０)