Risk assessments of PAHs and Hg exposure via settled house dust and street dust, linking with their correlations in human hair

Domestic energy, chemicals bioaccessibility and particle size were found as three critical factors for risk assessment of PAHs exposure via settled house dust (SHD) and street dust. ∑PAHs and Hg contained in SHD were significantly (p<0.01) higher in coal-burning households of Qingyang (8.45-121; 0.48-16.4μgg^-1) than households in Guangzhou (1.23-22.2; 0.004-10.6μgg^-1) and 90% coal-burning houses were estimated with unacceptable cancer risks (>10^-4) via SHD exposure. The highest accumulation trend of PAHs and Hg were found in <63μm particles, and different particle sizes resulted in large variations of the obtained risks (up to 10 fold). Bioaccessibility corrected PAHs led to a significant decrease on related cancer risks and decreased in the order of 1.9, 1.1, 0.6 and 0.4μgg^-1 with the increase of particle sizes (<63, 63-100, 100-280, 280-2000μm). Scalp hair was tested as an indicator of body burdens of PAHs (0.05-0.9μgg^-1) and Hg (0.04-1.6μgg^-1). Different PAHs profiles were found between PAHs in SHD and those of hair, indicating that exogenous exposure to PAHs adsorbed on dust was not the major source of hair PAHs.