Assessment of uranium migration and pollution sources in river sediments of the Ili River Basin using multiply statistical techniques.

Uranium (U) is a highly toxic radioactive element and limited to < 30 μg/L in drinking water by the World Health Organization. In this study, the concentration, distribution, possible source, and correlation with other elements of U were investigated in river sediments of the Ili River Basin. Metal contamination factors (CFs) and geoaccumulation index (I _geo ) were calculated, and both of them indicated that U in the survey region was unpolluted, slightly polluted, or moderately polluted (its concentration was ranged from 1.37 to 5.99 mg/kg). Notably, U pollution in the tributaries near the Wusun Mountain was evidently higher than those in the main streams of the Ili River and the Tekes River. Principal component analysis (PCA), cluster analysis (CA), and correlation analysis revealed that U was significantly positively correlated with Pb, and both of them might have originated from the dense coal mines in the areas of the Wusun Mountain. Sediment U in the main streams of the rivers was unpolluted or slightly polluted, which might be strongly influenced by the U contamination in their upstream tributaries. The results from this work showed that the source control of the coal-derived U pollution near the Wusun Mountain was critical to protect the aquatic environment in the Ili River Basin.