Contamination characterization and source apportionment of trace metals in riparian soils of Shuimo River in Urumqi

Abstract

In the present study, 122 topsoil (0-20 cm layer) samples were collected from riparian of Shuimo River in Urumqi, and the contents of 8 trace metals (Pb, Cu, Cr, Ni, Zn, Mn, V and As) were determined. Based on the results, the contamination level of soil by trace metals was evaluated by enrichment factor and geoaccumulation index, the distribution characteristics was investigated by geoaccumalation index and kriging interpolation and the sources of trace metals were analyzed by multi-variate statistics analysis. Results showed that the average contents of Pb, Cu, Cr, Ni, Zn, V and As did not exceed the Secondary Standard of National Soil Environmental Quality, but were higher than the background values of soils in Xinjiang.They exhibited an upper accumulation trend and different degrees of variability. Overally,the riparian soils of Shuimo River were slightly polluted. The major pollutant was Ni, which was detected in 72.7% of the samples, and reached light-to-moderate pollution. Cu and V were the secondary pollutants.Correlation analysis and principal component analysis showed that in the riparian soils of Shuimo River, Zn was positively correlated with Pb and Cu, while Ni was negatively correlated with Zn、Pb and Cr. Industrial activities, transportation, agricultural production and natural factors were identified as the main sources of soil trace metals for the study area. The potential ecology risk evaluation showed that the single factor potential ecological risk (Eri) and the integrated potential ecology risks(RI) of the eight trace metals were relatively low, and would not pose threats to the ecological environment of Shuimo River.