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In vitro bioaccessibility of lead in surface dust and implications for human exposure: A comparative study between industrial area and urban district

Bi, Xiangyang, Li, Zhonggen, Sun, Guangyi, Liu, Jinling, Han, Zhixuan
Journal of hazardous materials 2015 v.297 pp. 191-197
bioavailability, calcium, children, coal, combustion, emissions, humans, in vitro studies, lead, traffic, urban areas, zinc, China
In this study, ground surface dust samples from two contrasting areas, a former zinc smelting area in Guizhou Province and a common urban district in Wuhan city, Hubei Province, China, were assessed for in vitro Pb bioaccessibility using a physiologically based extraction test (PBET). Extremely elevated concentrations of Pb (220–6348mg/kg) and other trace metals were observed in the zinc smelting area. While moderate high metal concentrations (79–1544mg/kg of Pb) in the urban dusts were attributed to various urban activities, coal combustion and traffic emissions. Lead bioaccessibility in the stomach-phase varied from 17.6 to 76.1% and no significant difference was found between industrial and urban dust samples. Compared with the stomach-phase, Pb bioaccessibility in the more alkaline intestinal-phase was considerably lower (1.2–21.8%). A significantly negative correlation was found between dust Ca concentrations and Pb bioaccessibility in the intestinal-phase, suggesting that Ca plays an important role in reducing the bioaccessible Pb in the intestinal-phase. The estimated Pb exposure based on gastric bioaccessible Pb was 13.9 and 1.8μg/kgday for children living in the industrial and urban areas, respectively, accounting for 85% and 41% of their corresponding total Pb exposure.