Pollution Characteristics and Risk Assessment of Heavy Metals in Rural Road Dust for Preschool Children in Baiyin, a Long-Term Polluted Area of NW China

Abstract

In this study, the pollution characteristics and risks of heavy metals in road dust from long-term polluted areas were investigated. Fifteen road dust samples were collected from five villages along the Dongdagou Stream in Baiyin, China. All samples were tested for heavy metals using an inductively coupled plasma optical emission spectrometer (ICP-OES). Results showed that the concentrations of Cr, Mn, Ni, Cu, Zn, Cd, Pb, As, and Hg in the samples were 67.59 ± 6.01, 414.10 ± 31.62, 171.75 ± 25.92, 91.36 ± 118.56, 369.92 ± 504.87, 2.94 ± 4.37, 71.27 ± 76.56, 6.37 ± 2.55 and 1.46 ± 2.61 mg/kg, respectively. The Nemerow integrated pollution index (NIPI) showed that Minle (ML), Liangzhuang (LZ), Shuanghe (SH), Minqin (MQ) and Shapogang (SPG) villages were heavily polluted, with Hg being the main pollutant. Risk index (RI) results indicated that all the five villages were at considerable or high ecological risk. Hg was the main contributor to the potential ecological risk, accounting for 75.82%. Health risk assessments indicated that exposure to road dust heavy metals in preschool children occurs mainly by ingestion. The hazard indexes (HI) values of the five villages were above or close to 1.0, indicating the risk potential of non-carcinogens to preschool children. For carcinogens, the total carcinogenic risk did not exceed the acceptable range for preschool children. Overall, strong pollution and considerable/high ecological risk were found in the road dust of the present study area and the pollution might pose a non-carcinogenic risk to preschool children.