POLLUTION AND HUMAN HEALTH RISK ASSESSMENT OF HEAVY METALS IN KINDERGARTEN SURFACE DUST OF BENGBU CITY, CHINA

The concentrations of six heavy metals (Pb, Cu, Zn, Cr, Cd and Ni) from the surface dust of kindergartens in Bengbu have been investigated. The pollution degree of heavy metals and the level of children health risk are evaluated by the geo-accumulation index and the human health risk assessment method of the United States Environmental Protection Agency (USEPA). The results show that the average contents of Pb, Cu, Zn, Cr, Cd and Ni in the surface dust of kindergartens in Bengbu are 52.73, 58.19, 228.31, 39.56, 1.15 and 26.67 mg/kg, respectively. These values are 1.98, 2.85, 3.68, 0.59, 11.86 and 0.89 times of the soil background values in Anhui Province. The results of geo-cumulative index show that Cd is moderately polluted, Zn is light moderately polluted, Cu and Pb are slightly polluted, Ni and Cr are clean. The results of human health risk assessment show that the exposure dose of heavy metals from high to low is Zn, Cu, Pb, Cr, Ni, Cd in turn. Hand-mouth intake is the main way of heavy metal exposure invading human bodies. The total non-carcinogenic risk value is 0.211 and the total carcinogenic risk index is 1.24x10(-8), which are lower than the risk standard recommended by USEPA, and will not cause obvious health hazards to children.