我が国の塩素系難燃剤Dechlorane Plus による 汚染レベルについて

抄録

Dechlorane Plus (DP) is a chlorinated flame retardant developed as an alternative for Mirex (Dechlorane) in the1960s, and was detected by Hoh et al. in the environment for the first time in 2006. Thereafter DP as an emerging substance began to be investigated around the world, but the data was not available in Japan until 2011. We investigated contamination levels of DP in the various environmental media in Japan using a high-resolution gas chromatograph/mass spectrometer (HRGC/HRMS). The DP concentrations detected in Japan were 0.24-230 ng/g-dry in sediments, 1.7 ng/g-dry in soil, 74-270 ng/g-dry in outdoor dust (deposits adhering to windows and road sediments), 2.9-42 ng/g-dry in indoor dust, 0.082-1.2 ng/g-dry in plant leaves, and 5.5-8.0 pg/g-wet in vegetables. These results of our investigation indicated that various environmental matrices had been contaminated with DP, which was detected in high concentrations in deposits adhering to the outside of windows in Japan. In this study, it was found that DP concentrations of sediments in Japan were higher than in foreign countries, but levels in other media were comparable to other countries. DP concentrations in outdoor dust were higher than indoor dust, and it is suggested that DP mostly exists in outdoor environments in Japan. Mirex was present at low levels in most of the samples. Mirex was not used as a pesticide in Japan; therefore it may have been used as a flame retardant, Dechlorane. In outdoor samples (dust, soil and sediments), the ratio of an anti isomer of DP (f_anti) was slightly higher than in commercial DP. Furthermore, f_anti in indoor dust, plant leaves, and vegetables were lower than in outdoor samples, and were varied significantly.