Characteristics of Street Dust in Jiansheng Town, Chongqing City, China.

Samples of typical street dust were collected from Jian-sheng Town, Chongqing City and classified into four groups on the basis of particle size: 0-75, 75-150, 150-300, and 300- 1000 lm. The pollutant content and heavy metal composition of the samples were investigated. The particles in the 0-75, 75-150, 150-300, and 300-1000 lm groups had mass fractions of 20.82% ± 8.86%, 24.68% ± 9%, 30.83% ± 9.76%, and 23.68% ± 15.56%, respectively. The highest concentration of nutritional pollutants was detected in the 300-1,000 mm group, with total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC) concentrations of 3.07 ± 2.48, 0.64 ± 0.39, and 83.79 ± 65.28 g/kg, respectively. The lowest concentration of nutritional pollutants was observed in the 150- 300 lm group, with TN, TP, and TOC concentrations of 1.78 ±1.22, 0.51 ± 0.20, and 36.74 ± 24.64 g/kg, respectively. The nutritional pollutants presented similar mass fractions in the street dust samples with different particle sizes. Vegetation significantly affected the TOC content in the samples. The TOC content of the streets with rich vegetation was 1.90 ± 0.56 times that of the streets with less vegetation. The 150-300 µm group had the highest heavy metal mass percentage. Among the heavy metals detected in street dust, Cd, Cr, and Ni were mainly residuals; Cu and Pb were oxidizable; and Zn was mainly acid-extractable. [ABSTRACT FROM AUTHOR]