An integrated multivariate statistical analysis and hydrogeochemical approaches to identify the major factors governing the chemistry of water resources in a mountain region of northwest Italy

The aims of the present investigation are to evaluate the chemical controlling factors of the water resources and identify the source, as well as assess its quality with respect to domestic and irrigation criteria, to establish long-term environmental measures and a sustainable water resources management plan in the mountain regions. For these purposes, 28 water resources (14 drainage; 3 piezometric; 7 Arminaz Stream; 2 spring and 2 Dora River) samples were collected from different locations of the Mont de la Saxe region and analyzed for pH, electrical conductivity, total dissolved solids (TDS), total hardness, and major cations and anions. The pH of the water samples ranged from 7.6 to 11.6, indicating the alkaline nature of the water in the study area. The TDS ranged from 142.1 to 995.3 mg L-1 and exceeded the desirable limit of 500 mg L-1 at some sites. Ca-Mg-HCO3 and Ca-Mg-SO4 were the dominant hydrogeochemical facies; Ca2+ and Mg2+ were the dominant cations and HCO3- and SO42- were the dominant anions in the Mont de la Saxe region. High concentrations of SO42- were attributed to the dissolution of gypsum in the study area. The hydrogeochemical data show the mixing process from the springs pass through higher altitudes drains samples to lower drains samples as well as piezometer. The chemistry of water resources of the study area is mainly controlled by the rock-weathering phenomenon and ion exchange processes as well as by water flow direction of the area. High concentrations of TDS, Ca2+, SO42-, and TH and high salinity in many samples of the drainage and Arminaz Stream water make it unsuitable for domestic and irrigation uses in the study area. This study could be useful for future water resources management in the mountain regions.