title: Leaching characteristics of heavy metals and brominated flame retardants from waste printed circuit boards.
abstract: Leaching assessment on five heavy metals (copper, zinc, lead, nickel and cadmium) and two brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA), from waste printed circuit boards (WPCBs) were conducted using various leaching methods. The mean leaching concentrations of copper were the highest in both toxicity characteristic leaching procedures (TCLP) and synthetic precipitation leaching procedures (SPLP) tests at 8.6 mg/L and 1.1mg/L, while only lead (6.2mg/L) exceeded the TCLP criteria and Chinese EPA regulatory limit (both 5.0mg/L). However, PBDEs and TBBPA were not detected in TCLP and SPLP tests. Then the BFRs leaching trends and potential leachabilities were further investigated in actual landfill leachates using a modified method. Leaching characteristics that fast-leaching initially followed by slow-desorption over time were generally observed. In landfill leachate tests, the highest leaching concentrations of PBDEs and TBBPA were determined at 30.39 and 12.27 μg/L. Meanwhile, the highest leaching rates were estimated to reach 0.08% and 1.00%, respectively, which were significantly influenced by the dissolved organic carbon contents of extracts, the hydrophobicities of target BFRs and the specific surface areas of WPCBs materials. These results proved that leaching from WPCBs was a significant emission source of BFRs in landfill and electronic waste recycling dumpsite.
authors.affiliation: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237, PR China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Zhou
authors.forename: Jie
authors.initials: J
authors.lastname: Guo
authors.forename: Kuangfei
authors.initials: K
authors.lastname: Lin
authors.forename: Kai
authors.initials: K
authors.lastname: Huang
authors.forename: Jingjing
authors.initials: J
authors.lastname: Deng
mesh_terms: D059029:Electronic Waste; D005411:Flame Retardants / Q000032:analysis; D055768:Halogenated Diphenyl Ethers / Q000032:analysis / Q000737:chemistry*; D019216:Metals, Heavy / Q000032:analysis / Q000737:chemistry*; D011075:Polybrominated Biphenyls / Q000032:analysis / Q000737:chemistry*
chemical_list: D005411:Flame Retardants; D055768:Halogenated Diphenyl Ethers; D019216:Metals, Heavy; D011075:Polybrominated Biphenyls; C020806:tetrabromobisphenol A