Assessment of some bottled natural mineral waters and spring waters in Algeria using multivariate statistical analysis, hydrogeochemical approaches and water quality index (WQI)

In Algeria, the consumption of mineral waters has grown enormously, indicating that these waters have safe quality for drinking use. The objectives of the present study are to evaluate the physicochemical characteristics of 43 bottled mineral waters and to identify the main hydrogeochemical processes governing water chemistry using a combination of geochemical techniques and multivariate statistical approaches. The results revealed that the abundance order of cations and anions (mg/L) are Ca2+> Na+> Mg2+> K+, HCO3-> SO42-> Cl-> NO3-. In addition, the comparison between the obtained results and World Health Organization (WHO) standards showed that the analysed physicochemical parameters (pH, Na+, Cl-, SO42-, NO3-) are within the acceptable limits of the World Health Organization (WHO) for drinking except TDS, Ca (2+), Mg2+, K+, HCO3-, which exceed the WHO permissible limits in few water samples. Hydrogeochemical types in the study area were Ca2+-HCO3-, Ca2+-Mg2+-HCO3-, Ca-Mg2+-SO42-Cl-, Na+-HCO3- and Na+-Cl(-)types, with a low mineral and intermediate mineral contents based on Van der Aa's classi?cation. The Gibbs plot specifies that almost all samples (93%) fall in water-rock interaction dominance. The major hydrogeochemical processes acting are dissolution of carbonate minerals, ion-exchange mechanisms and silicate weathering. Principal component analysis (PCA) was applied to hydrochemical data of mineral water samples. The results suggest that hydrochemistry in the region is affected not only by geogenic processes but also is impacted by anthropogenic activities. The comparative evaluation of the different water quality indices (WQI) shows that there is a difference between indices values for the same water sample, which may be attributed to the weighting methods, aggregation methods, and the limits of classes used in the calculation of each index. The results from this study can provide the basis for local decision-makers to develop suitable water management strategies and protection against any pollution risk.