Quantificational exposure, sources, and health risks posed by heavy metals in indoor and outdoor household dust in a typical smelting area in China

Contamination of metals in household dust remains a concern for human health. However, few studies to date have been conducted on the contribution of both indoor and outdoor environments to the health risks posed by metals. This study was carried out to assess the potential health risks from both indoor and outdoor household dust and the respective contribution to the health risks for children. The results showed that household dusts were heavily polluted by metal(loid)s, which were up to 30 times higher than the relative background level, and were attributed to smelting activity. However, there are other pollution sources in indoor environments, since the I/O ratio values of Pb, Cd, and As were significantly higher than 1. HI values of Pb and As exceeded the threshold of (1) and accounted for approximately 60% and 24% to the HIt, respectively. The HIts of Zn, Cr, Mn, Hg, and Cu were mainly attributable to indoor dust exposure, particularly for Hg (73.44%), indicating non-carcinogenic health risks could be attributed more to the indoor dust exposure. This study highlights the potential risks of metal contamination in household environment, particularly indoor environment, on the health of children who live in the vicinity of smelting activity.