Human health risks associated with trace metals in dust of residential arid areas

Composite dust samples were collected on a monthly basis over a full year from Doha, Qatar. Inductively Coupled Plasma Mass Spectrometry (ICPMS) was used for the determination of total concentrations of Na, K, Mg, Ca, Li, Be, B, V, Cr, Fe, Mn, Co, Ni, Cu, Zn, As, Se, Sr, Cd, Ba, Al, Pb, Ag, TI, U, Sb, Si, Sn, Mo and Bi. A combined approach, merging conventional sampling and analysis with subsequent numerical calculations of the risk of exposure to toxic elements, was employed. For assessment of the health risks associated with the regular exposure to dust, the exposure routes related to the dermal contact and inhalation were considered. Our results indicate that the total non-carcinogenic health risk through exposure to different elements (Hazardous Quotients, HQ's) that are contained in the dust are quite low (well below unity) for both dermal contact and inhalation routes in all months of the year, i.e., there is no risk to the human health. There is no clear explanation for the seasonal variation of metals in the dust in the Qatar area. Several elements in the dust collected in the summertime have higher concentration than in the wintertime. This could be due to the weather conditions and natural depositions. However, the content of several elements (Pb, Zn, Cu, Sn and Li) showed elevation in the wintertime. For dermal exposure, the dominant contribution to the Hazardous Index (HI) comes from thallium (Tl) while for inhalation exposure several comparable contributions are related to Mn, Sb, Si, Ni, and Co. Long-term monitoring strategies are still needed for detailed research on dust pollutants and potential risks.