toxicity reduction of metal pyrithiones by near ultraviolet.pdf

1 TOXICITY REDUCTION OF METAL PYRITHIONES BY NEAR ULTRAVIOLET 2 IRRADIATION 3 4 Hideo Okamura1* 2 3 3 5 , Naomasa Kobayashi , Masamitsu Miyanaga , and Yusaku, Nogami 6 7 1 Laboratory of Marine Environmental Management, Faculty of Maritime Sciences, Kobe University, 8 Fukaeminami 5-1-1 Higashinada, Kobe 658-0022, Japan 9 2 Professor Emeritus, Doshisha University, Kamikyo-ku, Kyoto 602-8580, Japan 10 3 Department of Biochemistry, Okayama University of Science, Ridaicho 1-1, Okayama 700-0005, 11 Japan 12 13 14 15 *corresponding author: 16 fax: +81-78-431-6272, e-mail: okamurah@maritime.kobe-u.ac.jp 17 1 17 ABSTRACT 18 19 Zinc pyrithione (ZnPT) or copper pyrithione (CuPT) has been used as one of the effective 20 ship-antifouling agents alternative to organotin compounds. There have been a few data on their residue 21 levels in environmental matrices due to their unstability to light and a lack of suitable analytical 22 procedure. It is possible to investigate the fate of such compounds by toxicity alteration with certain 23 treatment. The purpose of this study was to evaluate the degradation of the pyrithiones through toxicity 24 reduction by near ultraviolet (UV-A) irradiation. Metal pyrithiones dissolved in acetonitrile were 25 irradiated with UV-A lamp for 0, 0.5, 1, and 2 hours, and were subjected for UV spectral measurement 26 and for toxicity evaluation by both sea urchin and freshwater rotifer bioassays. For bioassays, 27 photolysed samples were dissolved in dimethyl sulfoxide after evapo