Characteristics and sources of Pb exposure via household dust from the urban area of Shanghai, China

Household dust has been considered as an important pathway for children's environmental Pb exposure. Shanghai was one of the first cities in China that removed Pb from petrol and has been shown in our previous study to have the lowest childhood blood Pb levels in China. This study therefore examines household dust Pb (Pbᴴᴰ) in Shanghai in order to determine the extent and exposure risks of Pbᴴᴰ. Household vacuum cleaner dust samples (n = 40) were collected and analyzed for total Pb concentration, bio-accessible Pb concentration and Pb isotopic compositions (PbᴵC). The mean concentration of Pbᴴᴰ was 195 mg/kg, which is between 7 and 10 times the Pb concentration of background soil samples from Shanghai. Among the investigated homes, those living in neighborhoods with lower average estate prices have higher dust Pb exposure risks for children. Bio-accessibility of Pb in household dust ranged between 53 and 91%, with a mean value of 71%. Analysis of PbᴵC of household dust samples (²⁰⁸Pb/²⁰⁶Pb: 2.1096 ± 0.0054; ²⁰⁷Pb/²⁰⁶Pb: 0.8648 ± 0.0025) are a close match to PbᴵC of coal combustion and solid waste incineration and fit well with those of outdoor air PbᴵC and urban surface soil PbᴵC of Shanghai. The study shows that children living in Shanghai are subject to Pbᴴᴰ exposure, with children living in the homes with lower average price having increased susceptibility to Pbᴴᴰ exposure. The data indicate that Pbᴴᴰ is derived primarily from contemporary coal combustion and solid waste incineration rather than common legacy Pb sources (e.g., Pb petrol and paint). Practices including closing doors and windows on days with poor air quality or high wind and preventing shoe wearing inside homes will aid in minimizing outdoor surface soil and ambient particulate intrusion indoors.