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• Rubber tires and wire and cable were the main sources of PPDs and PPD-Qs in dust. • 6PPD, 6PPD-Q, IPPD and IPPD-Q were the most dominant compounds. • 32 TPs of 6PPD and 6PPD-Q were detected in dust. • The environmental hazards caused by PPDs and PPD-Qs may be underestimated. • Automotive repair shops workers have a higher risk of exposure. N , N ′-Substituted p -phenylenediamines (PPDs) are widely used as antioxidants in the rubber industry and are released into the environment in large quantities during the production and use of rubber products. We quantified PPDs and PPD quinone derivatives (PPD-Qs) in rubber consumer products, including car tires, rubber belts, rubber gloves, rubber cables, and rubber hoses, to obtain information on the degree of weathering over time during their use. Additionally, we investigated the occurrences and sources of PPDs and PPD-Qs in dust samples collected from four typical urban environments (roads, parking lots, automotive repair shops, and residences). The detected compounds included the highly toxic N -(1,3-dimethylbutyl)- N ′-phenyl-1,4-phenylenediamine quinone, which can cause acute mortality of coho salmon ( Oncorhynchus kisutch ). Concentrations of PPDs in the automotive repair shops reached 56.0 μg/g, and were much higher than in the other environments, while the residential samples had the lowest contaminant concentrations. In road and residential samples, N , N ′-di-2-naphthyl- p -phenylenediamine accounted for 17 %–30 % of the PPDs, and may have originated from different sources. We preliminarily identified 32 transformation products, and 11 of these were N , N ′-di-2-naphthyl- p -phenylenediamine transformation products. The average daily intakes of PPDs and PPD-Qs were calculated to assess the health risks of dust exposure in each environment. Workers had high total intakes of PPD 60.3 ng/(kg day) and PPD-Qs 20.1 ng/(kg day), and were at some risk of occupational exposure. These results improve our understanding of the environmental occurrences, sources, transformation, and health risks of PPDs and PPD-Qs.
Mao et al. (Mon,) studied this question.