[Sources, pollution statue and potential ecological risk of heavy metals in surface sediments of Aibi Lake, Northwest China].

In this paper, the surface sediment samples were harvested from Aibi Lake, and total contents of 8 heavy metals ( Cu, Pb, Zn, As, Hg, Cr, Ni and Cd) were determined. Then the sources, pollution statue, and potential ecological risk were analyzed by using multiple analysis methods. The results show that: (1) The order of the skewness for these 8 heavy metals is: Hg > Cd > Pb > Zn > As > Cu > Cr > Ni. (2) Multivariate statistical analysis shows that 8 heavy metals can be classified to 2 principle components, among which PC1 ( Cd, Pb, Hg and Zn) is man-made source factor and mainly came from all kinds of waste of agriculture; PC2 ( Cu, Ni, Cr and As) is natural source and was mainly controlled by the background of the natural geography of this area. (3) Accumulation of index evaluation results show that the order of pollution degree values of 8 heavy metals in surface sediments of Aibi Lake is: Cd > Hg > Pb > Zn > As > Cu > Ni > Cr. In all samples, heavy metals Hg, Cd and Pb all belong to low and partial moderate pollution statue, while Zn, As, Cr, Ni and Cu belong to no pollution statue in majority samples. (4) Potential ecological risk assessment results show that the potential ecological risk of heavy metals in surface sediments of Aibi Lake mainly caused by Cd, Hg and Pb, and they accounting for 42.6%, 28.6% and 24.0% of the total amount, respectively, among which Cd is the main ecological risk factor, followed by Hg and Pb. In all samples, the potential ecological risk index values (RI) of 8 heavy metals are all lower than 150, and they are all at low ecological risk levels. However, this research also shows that there have high content of Cd and Pb in the sediment. Therefore, we should make long-term monitoring of the lake environment.