Hydrogeochemical characterization and water quality assessment in Altay, Xinjiang, northwest China.

The safety of drinking and irrigation water is an issue of great concern worldwide. The rational development and utilization of water resources are vital for the economic and societal stability of Altay, an extremely arid area. In this study, three types of water samples (25 river waters, 10 groundwaters, 6 lake waters) were collected from main rivers and lakes in Altay and analyzed for electrical conductivity, total dissolved solids, pH, major ions (i.e., K+, Na+, Ca2+, Mg2+, HCO3-, Cl-, SO42-, NO3-, NO2-, F-), and trace elements (i.e., Al, Li, B, Sc, Ti, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, I, Ba, U). The water quality index (WQI), hazard quotient, carcinogenic risk, Na percentage, and Na adsorption ratio were then calculated to evaluate the water quality for drinking and irrigation. The results showed that the main hydrochemical type of river waters and groundwaters was Ca-HCO3, whereas that of lake water was mainly Na-SO4. The WQIs (9.39-170.69) indicated that the water quality in Altay ranged from poor to excellent. The concentrations of As, Ni, and U need to be carefully monitored since their average carcinogenic risks (for all waters collected, for adults) reached 0.05686, 0.06801, and 0.14527 and exceeded the safety risk levels (10-4-10-6) by at least 568 times, 680 times, and 1452 times, respectively. The result of Na% and SAR indicated that lake waters (with Na% of 62.92 and SAR of 41.63) and groundwaters (with Na% of 37.88 and SAR of 5.58) in Altay were unsuitable for irrigation, while river water (with Na% of 29.24 and SAR of 3.33) could meet the irrigation quality requirements. The results of this study could help promote reasonable water resource use among three types of waters and population protection in Altay.

Effects of lithium resource exploitation on surface water at Jiajika mine, China.

Heavy metal and metalloid (HMM) contamination of the water environment caused by mining activities is a great challenge to the global mining industry. HMMs released by various mines could easily enter the surrounding environment and pose serious threats to human health. Although the HMM pollution of surface water in various mines has been widely researched, relevant studies on the effects of mining activities on the surface water of hard-rock-type Li mines are scarce. Herein, a total of 81 water samples were collected from Jiajika mine for the first time, the largest hard-rock-type Li mine in Asia. The physical parameters and concentrations of HMMs and major ions of the samples were analyzed to evaluate the water quality and HMM level of surface water. Results showed that (1) most of the parameters analyzed adhered to the strictest guidelines of Chinese surface waters and the drinking water guidelines of WHO, except Mn, Pb, and As of a few samples from tailings-affected areas and Li-bearing areas; (2) mineral tailings obviously increased the pH and decreased the dissolved oxygen (DO) of the surrounding surface waters; (3) the highest concentrations of As (5.58 µg/L), Zn (81.8 µg/L), Ba (5.26 µg/L), and Co (0.33 µg/L) were observed around the tailings reservoir, whereas the highest concentrations of Cr (1.5 µg/L), Mn (380 µg/L), Pb (28.4 µg/L), and V (3.16 µg/L) were observed in Li-bearing areas; and (4) according to the statistical results, the concentrations of As, Cr, Ni, and V in surface water were mainly affected by mining activities, whereas those of Cu, Zn, Ba, Co, and Pb were dominantly affected by natural processes. These results provide useful information about water quality in relation to Li mining and can help the government make reasonable decisions regarding hard-rock-type Li resource exploitation activities.