Journal
SCIENCE OF THE TOTAL ENVIRONMENT
Volume 752, Issue -, Pages -Publisher
ELSEVIER
DOI: 10.1016/j.scitotenv.2020.141924
Keywords
Halogenated organic compounds; Brominated flame retardants; Mixed halogenated dibenzo-p-dioxins/dibenzofurans; E-waste; Soil
Categories
Funding
- Environmental Protection Scientific Research Project of Zhejiang Province, China [2017A005, 2017A006]
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E-waste recycling is known to release halogenated organic compounds (HOCs) and heavy metals, causing environmental pollution. This study investigated the occurrence and distribution of various contaminants in soil from an e-waste disposal site in Hangzhou. The concentrations of detected compounds were generally lower than those reported in informal e-waste sites, but still pose potential health risks.
E-waste recycling is well known for releasing halogenated organic compounds (HOCs) and heavy metals. This study investigated the occurrence and distribution of traditional and novel classes of contaminants, including chlorinated, brominated, and mixed halogenated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs, PBDD/Fs, PXDD/Fs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and polyhalogenated carbazoles (PHCZs), in soil from an e-waste disposal site in Hangzhou. PBDEs were the most abundant, at 343-69306 ng kg(-1), followed by PHCZs (896-41,362 ng kg(-1)), PCDD/Fs (349-19,396 ng kg(-1)), PCBs (51.3-1834 ng kg(-1)), PBDD/Fs (2.99-524 ng kg(-1)) and PXDD/Fs (0.104-21.2 ng kg(-1)). The detected target compound concentrations were generally lower than those reported in the literature for informal e-waste sites. Nevertheless, they can serve as a basis of information for evaluation and subsequent control. The toxic equivalent (TEQ) contributions from these contaminants (except PBDEs) decreased as follows: PCDD/Fs > PXDD/Fs > PHCZs > PCBs > PBDD/Fs. SDioxins (PCDD/Fs + PBDD/Fs + PXDD/Fs) accounted for 47.7%-97.2% of the total TEQs in the soil. OCDD, 1,2,3,4,6,7,8-HpBDF and OBDF were the dominant congeners, mainly derived from combustion and transport because of their low saturated vapor pressure. PXDFs were more abundant than PXDDs, and homologue profiles suggested a similar formation mechanism for PXDFs and PBDFs involving successive Br-to-Cl exchange. PHCZs were reported in soil from an e-waste disposal area for the first time, and their concentrations were several orders of magnitude higher than those of the other contaminants. Although the risk of human exposure in this study was estimated to be lower than the values recommended by the WHO (1-4 pg TEQ/kg bw/day), health implications still exist, and further investigations are necessary. (C) 2020 Published by Elsevier B.V.
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