title: Temporal and spatial contamination of polybrominated diphenyl ethers (PBDEs) in wastewater treatment plants in Hong Kong.
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, －47, －99, －100, －153, －154,－183 and －209) 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 L(-1) but decreased to 12-27 ng L(-1) in effluent, with removal efficiency ranged from 20 to 53%. High concentrations of PBDEs, ranging from 9 to 307 ng g(-1) dry weights, were detected in dewatered sludge. The predominated congeners in influent were BDE-47 and -209 but shifted to BDE-47 and －99 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.
authors.affiliation: Department of Biology & Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong SAR, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Deng
authors.affiliation: Nanjing College of Information Technology, 99 Wenlan Road, Qixia District, Nanjing 210046, China.
authors.forename: Hexiang
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Biology & Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong SAR, China; State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong SAR, China. Electronic address: bhntam@cityu.edu.hk.
authors.forename: Nora F Y
authors.initials: NF
authors.lastname: Tam
mesh_terms: D004784:Environmental Monitoring; D005411:Flame Retardants / Q000032:analysis; D055768:Halogenated Diphenyl Ethers / Q000032:analysis*; D006723:Hong Kong; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D005411:Flame Retardants; D055768:Halogenated Diphenyl Ethers; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Congeners; Dewatered sludge; PBDE contamination; Wastewater treatment plants