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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Air-Water Exchange of Polychlorinated biphenyls in Gao-Ping Coastal Areas, Taiwan

Mi, Zih-Rong 17 February 2011 (has links)
Persistent organic pollutants (POPs) were widely distributed in the environment, and may cause hazardous effects to human health. Among these pollutants, polychlorinated biphenyls (PCBs), due to their toxicity and bioaccumulation, have been banned in the mid 1970s in most countries. They are ubiquitous and highly persistent, and therefore, PCBs are of most concern for their potential to be globally transported through air-water exchange. Previous studies such as Fang et al.¡]2008¡^ and Chen¡]2010¡^have studied the air-water exchange of PCBs in Kaohsuing Harbor. This study not only continued monitoring this area but also included Gao-Ping coastal areas and Lanyu Island in order to determine the air-water exchange fluxes of PCBs in harbor and coastal area. The aim of this study was to determine the magnitude of PCB air-water exchange fluxes and dry deposition fluxes by measuring the gas/particle phase concentrations in ambient air and dissolved/particle phase concentrations in water column, and to analyze the compositional patterns of PCB homologs. Hierarchical cluster analysis (HCA) and principal components analysis (PCA) were performed with compositional patterns of commercial products such as Aroclor mixtures to gain a better understanding of pollution topography for PCBs . The concentrations of £UPCBs in the ambient air ranged from 116 to 439 pg m-3, with an average concentration of 164 pg m-3 . The average PCB concentrations in gas and particle phase were 161 pg m-3 and 2.91 pg m-3, respectively. The concentrations of £UPCBs in water column ranged from 14.1 to 1750 pg L-1, with an average concentration of 233 pg L-1. The average PCB concentrations in dissolved and particle phase were 162 pg L-1 and 70.4 pg L-1, respectively. The highest gaseous concentration of £UPCBs was observed in GRE in November, suggesting that wind direction and Linyuan Industrial Park may be the major contributor of PCBs there. However, the highest dissolved concentration of £UPCBs was found in KHH in August, indicating that rainfall and runoff of Typhoon Morakot were evident in source. Results from HCA, PCA and compositional patterns indicate that lower chlorinated congeners (dichlorobiphenyls to tetrachlorobiphenyls) were predominant in the gas and dissolved phase of ambient air and water column. In particle phase of ambient air and water column, PCB compositions were dominated by higher chlorinated congeners (tetrachlorobiphenyls to hexachlorobiphenyls). TEQ was used to determine the level of pollution for environment and human health. The average TEQ was 0.0008 pg-TEQ m-3 in gas-phase of ambient air and was 0.0006 pg-TEQ L-1 in dissolved phase in water. PCB114 was observed to be the predominant congener in this study. The average flux of air-water exchange was ¡Ï31.5 ng m-2 day-1, and was much higher than the average flux of dry deposition (¡Ð0.54 ng m-2 day-1). The net PCB fluxes in KHH suggest that annual air-water exchange was ¡Ï40.2 mg m-2 yr-1 and estimated yearly, 0.5 kg of PCBs were emitted from water column of Kaohsiung harbor to the ambient atmosphere.

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