“…The water temperature (T), pH and dissolved oxygen (DO) were measured in situ using a multi-parameter instrument (Multi 350i/SET, Munich, Germany), and the dissolved solids and isotopic compositions were determined in the laboratory. The hydrochemical compositions (K + , Na + , Ca 2+ , Mg 2+ , Cl − , SO 4 2− , HCO 3 − ) were measured at the Fourth Institute of Hydrogeology and Engineering Geology of Inner Mongolia based on China's national standards for the examination of natural mineral water for drinking [16] The major cation (K + , Na + , Ca 2+ , Mg 2+ ) concentrations were determined by using inductively coupled plasma-mass spectrometry (Agilent 7500ce ICP-MS, Tokyo, Japan), and the major anion contents (Cl − , SO 4 2− ) were determined using spectrophotometry (PerkinElmer Lambda 35, Waltham, MA, USA). The total dissolved solids (TDS) and HCO 3 − contents were determined by using acid-gravimetric analysis and base titration, respectively.…”