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PCBs and PCDD/Fs in soil from informal e-waste recycling sites and open dumpsites in India: Levels, congener profiles and health risk assessment

Chakraborty, Paromita, Selvaraj, Sakthivel, Nakamura, Masafumi, Prithiviraj, Balasubramanian, Cincinelli, Alessandra, Bang, John J.
The Science of the total environment 2018 v.621 pp. 930-938
burning, cities, combustion, copper, dibenzofuran, electronic wastes, health effects assessments, markets, models, persistent organic pollutants, polychlorinated biphenyls, polychlorinated dibenzodioxins, polychlorinated dibenzofurans, recycling, shredding, soil, streams, toxicity, India
Growth of informal electronic waste (e-waste) recycling sector is an emerging problem for India. The presence of halogenated compounds in e-wastes may result in the formation of persistent organic pollutants like polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during recycling processes. We therefore investigated PCBs and PCDD/Fs in surface soils explicitly from the informal e-waste recycling sites and nearby open dumpsites of major metropolitan cities from four corners of India, viz., New Delhi (North), Kolkata (East), Mumbai (West) and Chennai (South). In the informal e-waste recycling sites, the range of Σ26PCBs (0.4–488ng/g) and ƩPCDD/Fs (1.0–10.6ng/g) were higher than Ʃ26PCBs (0.3–21ng/g) and ƩPCDD/Fs (0.15–7.3ng/g) from open dumpsites. In the e-waste sites, ƩPCDDs were found with increasing trend from ƩTetraCDD to OctaCDD, whereas ƩPCDFs showed a reverse trend. The dominance of PCDF congeners and maximum toxicity equivalents (TEQ) for both PCDDs (17pg TEQ/g) and PCDFs (82pg TEQ/g) at Mandoli in New Delhi has been related to intensive precious metal recovery process using acid bath. Among dumpsites, highest TEQ for PCDD/Fs was observed at Kodangaiyur dumpsite of Chennai (CNDS-02, 45pg TEQ/g). Positive Matrix Factorization (PMF) model identified distinct congener pattern based on the functional activities, such as e-waste dismantling, shredding, precious metal recovery and open burning in dumpsites. E-waste metal recovery factor was loaded with 86–91% of PCB-77, -105, -114, -118 and 30% of PCB-126, possibly associated with the burning of wires during the copper extraction process. Almost 70% of the Ʃ26PCB concentrations was comprised of the dioxin-like PCB congeners with a maximum concentration of 437ng/g at New Moore market in Chennai, followed by Wire Lane (102ng/g), in Mumbai. We speculate that PCB-126 might have resulted from combustion of plastic materials in e-waste stream and dumped waste.