DISTRIBUTION AND FATE OF POLYCHLORINATED BIPHENYLS (PCBS) IN RIVERINE WATER OF THE PEARL RIVER DELTA

Nineteen PCBs (polychlorinated biphenyls) congeners were detected in riverine water samples collected at eight outlets of the Pearl River Delta (PRD) via gas chromatography mass. Total PCBs concentrations in the dissolved and particulate phases were 0.02-2.55 and 0.05-5.14 ng/L, respectively. The log Koc of PCB congeners in water ranged from 4.71 to 5.18, and a nonlinear correlation between the observed log Koc and log Kow for PCBs was found, suggesting nonequilibrium state for PCBs between the dissolved and particulate phase. The third phasecolloidal phases adsorbed 2.3-52.6% of PCB congeners in filtrate. Total net air-water exchange flux of PCBs in the outlets was -1.41102 ng/m2 day, suggesting net fluxes of total PCB congeners from water into air in the PRD, and the water body as an important source of local atmospheric PCBs.