Water quality for agricultural irrigation and aquatic arsenic health risk in the altay and tianshan mountains, central asia

Abstract

Due to a lack of water-quality studies compared with water-quantity studies, an investiga-tion into the factors influencing the hydrochemical composition of the rivers in the Tianshan and Altay Mountains was conducted with a model of multiple linear regression, while the suitability of the water quality for irrigation and the health risks of arsenic (As) were assessed with classical evaluation methods. The results suggest that 44.0% of the water samples from the Altay Mountains fell into the Ca-HCO3 category type, 48.0% of the water samples were of the Ca-HCO3-Cl type, and the remaining samples belonged to the Ca-Na-HCO3-Cl type. In the Tianshan Mountain area, 58.6% of the water samples fell into the Ca-HCO3 hydrochemical category, 20.7% of the water samples were of the Ca-HCO3-Cl type, and 20.7% of the water samples belonged to the Ca-Na-HCO3-Cl type. The major ions in the water were dominated by the control of the water and rock interaction. The interaction between water and rock in the Altay area controlled 69.2% of the overall variance in the As content in the river waters, and it dominated 76.2% of the variance in the Tianshan region. The river waters in the Altay and Tianshan Mountain regions are suitable for agricultural irrigation with excellent-to-good water quality. The results also suggest that there is no non-carcinogenic risk and that the carcinogenic risk is between the acceptable/tolerable risk range of 10−6 –10−4, except only one sample in Tianshan Mountain region. The research methodology provided a reference for revealing the potential sources of toxic element pollution, and the results provided a scientific basis for regional agricultural irrigation, as well as a reference for decision making on the environmental protection of the watershed.