[Distribution Characteristics of Heavy Metals in the Street Dusts in Xuanwei and Their Health Risk Assessment].

Relationship between high lung cancer incidence in Xuanwei residents and environmental pollution has been a hot topic in the field of environmental sciences. Street dusts in Xuanwei power plant area as well as its upwind area (Banqiao town) and downwind area (Laibin town, Tangtang town) were collected. Chemical elements in the street dust samples were investigated using ICP-MS. Health risk assessment of heavy metals in the street dusts was carried out using the US EPA Health Risk Assessment Model. Our results showed that the mass level of Al, V, Ni, Co, Zn and Cd in street dusts followed the order of Xuanwei power plant > Laibin town > Tangtang town. The mean concentrations of V, Cd, Cr, Cu, Mn, Co, Ni, Pb, As and Zn were all higher than the background values in Yunnan soil, indicating that the street dusts of Xuanwei city have been heavily polluted by those metals. The health risk assessment results showed that the non-cancer hazard risks induced by the 10 heavy metals were higher to children compared to adults. The heavy metals in street dust were mainly ingested by human bodies through hand-mouth ingestion. The 5 carcinogenic metals, including Cd, Cr, Ni, Cr and As, had a potential risk of carcinogenicity in human after exposed to the dusts. Cr was the major toxic element to the local children's health.