Chlorinated and Parent Polycyclic Aromatic Hydrocarbons in Environmental Samples from an Electronic Waste Recycling Facility and a Chemical Industrial Complex in China

Abstract

Chlorinated polycyclic aromatic hydrocarbons (CIPAHs) are a class of halogenated contaminants found in the urban atmosphere; they have toxic potential similar to that of dioxins. Information on the sources of CIPAHs is limited. In this study, concentrations of 20 CIPAHs and 16 parent PAHs were measured in electronic wastes, workshop-floor dust, vegetation, and surface soil collected from the vicinity of an electronic waste (e-waste) recycling facility and in surface soil from a chemical industrial complex (comprising a coke-oven plant, a coal-fired power plant, and a chlor-alkali plant), and agricultural areas in central and eastern China. High concentrations of SigmaCIPAHs were found in floor dust (mean, 103 ng/g dry wt), followed in order of decreasing concentration by leaves (87.5 ng/g drywt), electronic shredder waste (59.1 ng/g dry wt), and soil (26.8 ng/g dry wt) from an e-waste recycling facility in Taizhou. The mean concentration of SigmaCIPAHs in soil from the chemical industrial complex (88 ng/g dry wt) was approximately 3-fold higher than the concentration in soil from e-waste recycling facilities. The soils from e-waste sites and industrial areas contained mean concentrations of SigmaCIPAHs 2 to 3 orders of magnitude higher than the concentrations in agricultural soils (ND-0.76 ng/g), suggesting that e-waste recycling and chlorine-chemical industries are potential emission sources of CIPAHs. The profiles of CIPAHs in soil and dust were similar to a profile that has been reported previously for fly ash from municipal solid waste incinerators (6-CIBaP was the predominant compound), but the profiles in vegetation and electronic shredder waste were different from those found in fly ash. Concentrations of 16 parent PAHs were high (150-49,700 ng/g) in samples collected from the e-waste recycling facility. Significant correlation between SigmaCIPAH and SigmaPAH concentrations suggests that direct chlorination of parent PAHs is the major pathway of formation of CIPAHs during e-waste recycling operations. Dioxin-like toxic equivalency quotients (TEQs) for CIPAHs and PAHs in samples were calculated on the basis of relative potencies reported for CIPAHs and PAHs. The highest mean TEQ concentrations of CIPAHs (518 pg-TEQ/g) were found for workshop-floor dust, followed by leaves (361 pg-TEQ/g), electronic shredder waste (308 pg-TEQ/g), soil from the chemical industrial complex (146 pg-TEQ/g), and soil from the sites of the e-waste recycling facility (92.3 pg-TEQ/g). With one exception, the floor dust samples, the TEQ concentrations of CIPAHs found in multiple environmental matrices in this study were higher than the TEQ concentrations of PCDD/Fs in the same samples reported in our earlier study.