Multivariate Statistical Analysis of Saline Water — A Case Study: Sabkha Oum LeKhialate (Tunisia)

The hydrochemistry of the saline system in high arid environment is controlled by several processes including evaporation, water-rock interaction, precipitation /dissolution etc.Hydrochemical data of 80 wells from the catchment area of sabkha Oum leKhialate, southern Tunisia and 9 parameters (pH, TDS, Na + , Ca 2+ , SO 4 2-, Mg 2+ , K + , Cl -, HCO 3 -) show that the abundance of major ions from the sabkha is as follows: Na>Ca>Mg>K and SO 4 >Cl>HCO 3 .Multivariate statistical analysis methods such us correlation analysis, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to identify the geochemical processes controlling the chemistry of saline water in the catchment area of the sabkha.HCA reveals four major water groups (C1-C4).Samples of the sabkha from clusters C1, C2 to C3 have Na-SO 4 -Cl, Na-SO 4 and Na-Cl-SO 4 water type respectively.Samples from C4 show Ca-HCO 3 -SO 4 -Cl water type are located in recharge area.Using PCA, two factors account for 72.69 % of the total variance of the data set.Results of statistical analysis reveal that the major source of sulfate sodium deposit is the process of evaporation, cationic exchange between Ca and Na in clay formation and mineral precipitation.