Estimation of the transport of persistent organic pollutants via air-water exchange requires precise field concentrations from advanced experimental techniques and adequate physic-chemical parameters generated from proper methods. In this study, concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in the ambient air and water column of Kaohsiung Harbor lagoon were measured and used to determine the air-water exchange fluxes of these compounds from December, 2003 to January, 2005. The Whitman¡¦s thin-film model was used by taking temperature and salinity corrected Henry¡¦s law constants into the model to calculate the fluxes. In addition, particulate concentrations and composition in the ambient air and water column were used to apportion PAH sources and dry particle deposition of PAHs, PCBs and HCB. Instantaneous air-water exchange fluxes of PAHs, PCBs and HCB were calculated from twenty-two pairs of air and water samples. The highest net volatile (+3560 ng m-2 day-1) and absorptive (-1230 ng m-2 day-1) PAH fluxes in this study were both obtained from the three-ring PAH, phenanthrene on April 7 and January 27 in 2004, respectively. Differences of flux magnitude and direction between dry and rain season were obvious for PAHs in this study. Most net fluxes of PCB homologues and HCB in this study are from water to air (net volatilization). The highest net volatile flux observed was +172 ng m-2 day-1 (dichlorobiphenyl) in December, 2003 due to elevated wind speed and dissolved concentration, while the only net absorptive flux observed in this study was -0.03 ng m-2 day-1 (dichlorobiphenyl) in January, 2004. Mean daily PAH diffusive fluxes were -727 ng m-2 day-1 influx in dry season but +808 ng m-2 day -1 efflux in rain season and integrated 3.6 kg and 4.0 kg of PAHs were absorbed into and emitted from harbor lagoon surface waters in dry and rain seasons, respectively. The net PCBs and HCB fluxes suggest that the annual sum of 69 PCBs and HCB measured in this study were mainly volatile (57.4 and 28.3 ¡Ñ103 ng m-2 yr-1, respectively) and integrated 1.5 kg and 0.76 kg of PCBs and HCB emitted from harbor lagoon surface waters to ambient atmosphere in the year. Sources apportionment by the isomer ratios, PAHs in the air phase were mainly from grass, wood and coal combustion and some from liquid fuel combustion. Unlike that in air phase, fluoranthene / fluoranthene + pyrene ratios of water phase suggest PAHs were from incomplete-combusted fuel particles emitted from vehicle exhaust. Principal component analysis (PCA) extracted three meaningful PCs for air and water samples, respectively. For the air samples, the three major sources suggested by three sources are vehicular emissions, volatilization to the air from contaminated soil or waters and the coal-burning emission. Among the water samples, the three major sources suggested by three sources are vehicular emissions, oil spill source and coal-burning emission. Air particulate concentrations of PAHs, PCBs and HCB were also used to calculate their dry particle deposition. Throughout our sampling campaigns, PAH dry particle fluxes were quite comparable to fluxes of air-water exchange. On the contrary, PCB and HCB dry particle deposition flux were negligible comparing to their air-water exchange fluxes. Our results suggest PAHs exhibits strong absorptive or weaker volatile fluxes in the dry season but the opposite in the rain season. However, for PCBs and HCB, Kaohsiung Harbor water is potentially an important source to ambient air.

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.

This study investigated the concentrations of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the particulate and dissolved phase, as well as concentrations of PAHs in the sediment in Kaohsiung Harbor lagoon. Sources of PAHs in the water column were determined by isomer ratios, hierarchical cluster analysis (HCA) and principal components analysis (PCA). The net and annual fluxes of PAHs were calculated after a lagoon-wide water sampling campaign and compared with those found in a previous study (Fang, 2007) in which data from only one water sampling station was used. ¡@¡@In rain season, total PAH concentrations ranged from 21.6 to 36.2 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 15.5 to 27.2 ng/L and from 3.4 to 8.6 ng/L, respectively. In dry season, total PAH concentrations ranged from 13.2 to 31.5 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 8.0 to 21.1 ng/L and from 5.3 to 10.5 ng/L, respectively. Total PAH concentrations were found higher in rain season than in dry season. The highest total PAH concentration in dry season was observed in Chianjen River estuary. Relatively high PAH concentrations were also observed in these southern stations of Kaohsiung Harbor because of their location near Dalin industrial park. Total PAH concentrations ranged from 81.7 to 2279 ng/g for sediment samples, with average of 895 ng/g. The correlations between PAH concentrations and organic carbons, water temperature, salinity and suspended particles were also examined in this study. PAH concentration in dissolved phase was negatively correlated with water temperature (p<0.05). PAH concentration in sediment was positively correlated with organic carbons (p<0.05), and negatively correlated with median diameter (p<0.01). The logKoc¡ÐlogKow relationship in rain and dry season was compared with literature. It was found that the logKoc values were higher than those reported in literature, suggesting that soot particles might play an important role in the transport and distribution of PAHs in the study area. In rain season, PAHs in dissolved phase were mainly from pyrogenic origins; while mainly from petrogenic origins in particulate phase. In contrast, in dry season, PAHs in dissolved phase were mainly from petrogenic origins; while mainly from pyrogenic origins in particulate phase. In addition, it was found, relatively, that petrogenic pollution was introduced maily from the northern area of the lagoon. In rain season, total PCB concentrations ranged from 1.1 to 2.7 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 0.42 to 2.1 ng/L and from 0.24 to 1.4 ng/L, respectively. In dry season, total PCB concentrations ranged from 0.54 to 1.3 ng/L for water samples, with dissolved and particulate phase concentrations ranged from 0.20 to 0.74 ng/L and from 0.32 to 0.76 ng/L, respectively. The direction of net fluxes of PAHs in this study are from water to air (net volatilization) in summer. In winter, however, the absorptive PAH fluxes obtained for four to six-ring PAH, such as fluoranthrene, chrysene + triphenylene and benzo[a]anthracene, indicating that PAHs were absorbed into surface waters. According to our results, it was suggested that the results from previous study (Fang, 2007) might underestimate the net fluxes of Pyrene and total fluxes in dry season. The annual fluxes of PAHs estimated in this study were 212 mg/m2 /year and 5.7 kg of PAHs were emitted annually from the harbor lagoon surface waters to the ambient atmosphere.