Ecological Heavy Metals Risk of Saline Lake Sediments in Northwestern China

Lake sediment as a potential sink and source of contaminants, it is still relatively less known about than the ecological heavy metals risk in an arid region saline lake. The goal of this study aimed to reveal concentrations of Cr, Ni, Cu, Zn, As, Cd and Pb in saline lake sediments, and to evaluate its pollution status, potential ecological risks and sources for sediments in the study area. Here we analyzed 13, 15 and 8 sediment samples from Ebinur Lake, Barkol Lake and Dabancheng Saline Lake, respectively. The mean concentrations of Cr (74.55 mg kg(-1)), Cu (27.75 mg kg(-1)), Zn (73.00 mg kg(-1)), As (37.65 mg kg(-1)), and Cd (0.31 mg kg(-1)) were higher than the background values of the Xinjiang, and the mean enrichment factor (EF) and geo-accumulation index (I-geo) showed that As (EF = 7.44, I-geo = 1.35) and Cd (EF = 11.09, I-geo = 0.50) in saline lake sediments were moderate and partially seriously contaminated, while Cr, Zn and Cu caused moderate pollution. The potential ecological (RI) seven heavy metals risk assessment degree decreased in the following sequence: Cd (78.77)>As (32.22)> Cu (5.22)>Ni (4.28)>Pb (3.27)>Cr (3.21)>Zn (1.07), and the RI for Cd exhibited moderate to considerable risk. The As and Cd were the major risk factors among the seven metals. Correlation analysis, principal component analysis and hierarchical cluster analysis deduced that Cu, Ni, and Zn originate mainly from a geological background, while As, Cd and Cr were mainly from anthropogenic sources. Anthropogenic activities lead to heavy metals enrichment in sediments, while As and Cd are the primary contaminants in saline lake sediments in northwestern China.