Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6328393 | Science of The Total Environment | 2015 | 10 Pages |
Abstract
Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants which cause adverse effects to human health and environments. Wastewater treatment plants (WWTPs) receive PBDEs from various discharges but also release them back to the environment via treated effluent and sludge, depending on the removal efficiency of WWTPs. This study investigated the contamination of PBDEs in primary influent, final effluent and dewatered sludge in four WWTPs in Hong Kong from October 2011 to January 2013. Results showed that the concentrations and composition profiles of eight PBDE congeners (BDE-28, ï¼47,  ï¼99,  ï¼100, ï¼153,  ï¼154, ï¼183 and ï¼209) differed among WWTPs and fluctuated during the study period. Higher concentrations of PBDEs were detected in the influent and dewatered sludge from the two WWTPs receiving both domestic and industrial wastewaters than the two serve mainly residential and commercial districts. However, the PBDE concentrations in the effluent were comparable among WWTPs. The concentrations of Σ8PBDEs (total of eight congeners) in the influent of all WWTPs ranged from 1 to 254 ng Lâ 1 but decreased to 12-27 ng Lâ 1 in effluent, with removal efficiency ranged from 20 to 53%. High concentrations of PBDEs, ranging from 9 to 307 ng gâ 1 dry weights, were detected in dewatered sludge. The predominated congeners in influent were BDE-47 and â 209 but shifted to BDE-47 and ï¼99 in effluent and BDE-209 in dewatered sludge. Every day, it is estimated 0.66-73 g PBDEs entered the four WWTPs, while 0.38-38 g and 0.17-17 g PBDEs were discharged to the surrounding waters via effluent and disposed to landfill sites in sludge form, respectively. These results indicated that the four WWTPs in Hong Kong were not designed for effectively removal of PBDEs, 52-80% of the incoming PBDEs were still remained in effluent and 21-45% was precipitated in sludge, both outputs became significant contamination sources.
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Environmental Science
Environmental Chemistry
Authors
Dan Deng, Hexiang Chen, Nora F.Y. Tam,