The source apportionment, pollution characteristic and mobility of Sb in roadside soils affected by traffic and industrial activities.

Antimony (Sb), as an emerging pollutant, has aroused people's concerns for its wide usage in industrial production. In this study, we identify and quantify the traffic-derived Sb and investigate its mobility in roadside soils affected by traffic and industrial activities. 73 surface roadside soils and 5 transects in three areas nearby different industries (smelting, power and refining, and waste incineration) were collected and analyzed. Results showed that the Sb concentration ranged between 0.54 and 9.32 mg/kg, and the mean EF value was 4.63, which indicated moderate to significant Sb enrichment. Significantly high concentrations of Sb occurred at locations with heavy traffic and frequent braking process, with an average concentration of 4.13 mg/kg, compared to the control sites (2.01 mg/kg). Moreover, Sb diffused exponentially with increasing distance from road edges. These results suggested that traffic activities were the main source of Sb in roadside soils. According to the quantitative calculation, the average contributions from traffic, industrial activities and soil parent material to Sb accumulation in roadside soils were 50.73%, 21.38% and 27.88%, respectively. Even though Sb was slightly mobile, roadside soils was a persistent source of potentially mobile Sb which may release into water and cause long-term environmental risk.