Volume 10, No. 4, August 2010, Pages 378-390 PDF(858 KB)
Dry and Wet Depositions of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in the Atmosphere in Taiwan
Ya-Fen Wang1, Hsiao-Chung Hou2, Hsing-Wang Li2,3, Long-Full Lin4, Lin-Chi Wang5, Guo-Ping Chang-Chien5, Yen-Sheng You1
1 Department of Bioenvironmental Engineering and R&D Center of Membrane Technology, Chung Yuan Christian University, 200 Chung-Pei Road, Chung-Li 320, Taiwan, ROC
2 Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan, ROC
3 Sustainable Environment Research Center, National Cheng Kung University, Tainan 70101, Taiwan, ROC
4 Department of Environmental Engineering, Kun Shan University, Yung-Kang 710, Taiwan, ROC
5 Department of Chemical and Materials Engineering, Cheng Shiu University, Kaohsiung 833, Taiwan, ROC
The study has investigated the annual variation of the dry and wet depositions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) among different kinds of areas. A commercial suburban area, an industrial urban area, a coastal rural area and an agricultural rural area were chosen to measure the PCDD/F depositions in each season. The mean TEQ concentration, dry deposition flux and wet deposition in the industrial urban area all had the highest values, at 0.0958 pg I-TEQ/Nm3, 29.1 pg I-TEQ/m2-d and 47.8 pg/L, respectively. Additionally, the annual total deposition flux of PCDD/Fs in the commercial, industrial, coastal and agricultural areas was 168, 310, 135 and 115 ng/m2-year, respectively. The seasonal change of PCDD/Fs in air could be affected by heating and temperature inversion in winter or photodegradation and OH radical reaction in summer. The various homologue profiles of PCDD/Fs probably affect the distribution in environmental sinks, such as sediments or the living organisms in rivers or seas. Additionally, the results of statistical analysis indicated that PCDD I-TEQ dry deposition flux (ng I-TEQ/m2-month) was negatively correlated with the ambient temperature (r = –0.843) for the agricultural rural area, possibly due to vapor pressure (temperature-dependent) effect on the gas/particle PCDD/F partitioning. Furthermore, the PCDD/F concentration of wet deposition flux (ng I-TEQ/m2-month) was positively correlated with the monthly rainfall (r = 0.826–0.988) at the four sampling areas.
PCDD/Fs; Dry deposition; Wet deposition; Fluxes; Atmosphere.