Atmospheric deposition is a key route for dioxins to transport from emission sources to ecological receptors. Atmospheric bulk deposition of dioxins (PCDD/Fs and co-PCBs) was measured monthly over a year at an industrial site and a rural site in Japan to assess the deposition fluxes and seasonal variations. Daily average deposition flux was 83 pg-TEQ/m2/day for the industrial area, and 33 pg-TEQ/m2/day for the rural area. Rural area showed a lower deposition flux than industrial area, but both of the areas showed higher deposition fluxes than the average value of Japan (21pg-TEQ/m2/day, 1998) investigated by Japanese Environmental Agency in 1998. The contributions of co-PCBs were about 5% of the total TEQ in both areas. With temperature decrease from autumn to winter, the dioxin flux increased at the industrial area, but lightly decreased at the rural area, showing a different seasonal variation trend in deposition fluxes in the two areas. It was also found that the lower chlorinated PCDD/Fs accounted for higher percentage in the industrial area than that in the rural area.
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