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 investigation 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.

Environmental significance and hydrochemical characteristics of rivers in the western region of the Altay Mountains, China

“…For instance, the pH values of the Ertix River and Ulungur River were also alkaline, with a small range of variation. These rivers contained abundant Ca 2+ , Na + , HCO3 -, and SO4 2-, which are the most common cations and anions (Liu et al, 2021). Additionally, the average TDS in the Ertix River and Ulungu River is reported to be significantly higher than that in the western region of the Altay Mountains, which may be attributed to the comprehensive impact of geological conditions, supply sources, climatic factors, and human activities (Zabaleta et al, 2007).…”

“…The landscapes are characterized by glaciers, snow, permafrost, forestlands, and grasslands from high to low elevations. The entire region has a typical temperate continental climate (Liu et al, 2021). The local climate may also be influenced by westerlies and polar air masses.…”

“…Numerous previous studies have investigated the hydrochemistry of prominent rivers worldwide, including the Nile River (Dekov et al, 1997), Amazon River (Stallard and Edmond, 1983), and Ganges River-Yarlung Zangbo River (Galy and France-Lanord, 1999). In China, researches predominantly focused on hydrochemical characteristics of rivers originating from the Tibet Plateau , Pamir Plateau (Wu et al, 2020), Qilian Mountains (Li et al, 2014), Tianshan Mountains (Yapiyev et al, 2021), and Altay Mountains (Liu et al, 2021). These researches have provided crucial insights into regional environmental changes, such as variations in the spatial and temporal distribution of river water chemistry (Jiang et al, 2015), as well as the sources of solutes in river water and the factors governing them Dong et al, 2022).…”

“…It not only serves as a representative arid region influenced by westerly circulation but also functions as a significant water source conservation area in northern Xinjiang Uygur Autonomous Region of China. In recent years, researchers have increasingly focused on water resources and environmental issues in the Altay Mountains, including river water chemistry (Liu et al, 2021), river water quantity (Zhang et al, 2010;, and soil-related concerns (Goenster-Jordan et al, 2021). However, studies on river water chemistry have typically relied on single-time-period sampling results to interpret concentration patterns, neglecting seasonal and annual variations (Liu et al, 2021).…”

“…In recent years, researchers have increasingly focused on water resources and environmental issues in the Altay Mountains, including river water chemistry (Liu et al, 2021), river water quantity (Zhang et al, 2010;, and soil-related concerns (Goenster-Jordan et al, 2021). However, studies on river water chemistry have typically relied on single-time-period sampling results to interpret concentration patterns, neglecting seasonal and annual variations (Liu et al, 2021). Furthermore, there is a lack of information on spatial patterns, such as the elevation distribution of ion concentration, due to scattered data and sampling discontinuities.…”