Hydrochemical and isotopic characters of surface water in agricultural oases of the Tianshan Mountains, Northwest China

Hydrochemical Characteristics and the Relationship between Surface and Groundwater in a Typical ‘Mountain–Oasis’ Ecosystem in Central Asia

“…In spring, dryness, less precipitation and vigorous evaporation led to the enrichment of stable isotopes in the river water. In summer, more precipitation and a large amount of ice melt water (with low isotopes) recharged to river water, which resulted in the dilution of stable isotopes in river water samples [4,17,26]. The stable isotope composition of river water samples in the study area showed an obvious spatial variation (Figure 4).…”

“…The measurement results were reported by the Vienna Standard Mean Ocean Water (V−SMOW). Dual−column instrument (Dionex DX−100, Dionex, Sunnyvale, CA, USA, analytical errors were: Ca 2+ (±0.4 mg/L), Mg 2+ (±0.7 mg/L), Na + (±0.1 mg/L), K + (±0.1 mg/L), Cl − (±0.1 mg/L), SO 4 2− (±0.3 mg/L), HCO 3 − (±0.3 mg/L)) was used to measure the major ion concentration of surface and ground water. Some parameters (pH, water temperature and the total dissolved solids (TDS)) were tested in situ using a portable multiparameter instrument (Manta 2) adjusted with a standard solution.…”

“…The relatively odious climate environment (characterized by such factors as fluctuating temperature, scarce precipitation and strong evaporation) leads to unequal spatial and temporal distributions of water resources in inland areas of Central Asia [3], which further increases the disparity between supply and demand for regional water resources. With the increases in population, economic growth, social progress and the development of industrial and agricultural production and especially with the rise of modern industry and the expansion of cities, human demand for water resources is increasing [4]. In order to meet the growing demand for water, human beings have taken various measures to expand the development of water resources.…”

“…This has achieved short-term economic benefits but it has also had a serious impact on the ecological environment. The problems of water shortage and water insecurity are becoming more and more serious, especially in inland areas of Central Asia [4]. Nowadays, groundwater contamination is a critical issue in many countries, since it is directly related to water usage, food safety, and human health [5].…”

“…However, studies of typical mountain-oasis ecosystems in Central Asia are relatively underdeveloped. Under the combined influence of regional climate change and large-scale human activities, it has become important for regional sustainable development to explore hydrochemical compositions and relationships in varietal water bodies, especially in Central Asia [4,8].…”