Assessment of source and health risk of metal(loid)s in indoor/outdoor dust of university dormitory in Lanzhou City, China

The pollution of metal(loid)s from indoor and outdoor dust is of great concern because of its impact on human health. The concentrations of nine metal(loid)s (Mn, Cu, Zn, Cd, Cr, Ni, Pb, Hg, and As) were investigated in indoor and outdoor dust samples of university dormitories in winter and summer seasons in Lanzhou City, China. This study revealed the variations of metal(loid) concentrations in dust samples with the seasonal scale and floor heights. The results showed that the concentrations of some metal(loid)s (Cu, Cd, Ni, Pb, and As) in dust samples collected in winter were higher than those of the dust samples collected in summer. The Hg in indoor dust was mainly derived from building materials and indoor human activities. Additionally, the concentrations of some metal(loid)s (Hg, Mn, As, Cu, Cd) in dust samples varied with the height of the floors from ground level. The concentrations of Hg in dust samples collected on upper floors (9–16th floors) were higher than those collected on down floors (1–8th floors), while Mn and As were the opposite of that. Cu and Cd concentrations increased as the floor height increased. Our results demonstrated that the adults and the children (particularly the children) endured potential health risks due to exposure to metal(loid)s from both indoor and outdoor dust in the studied area.