Hydrogeochemical study of groundwater quality in the west of Sidi Allal Tazi, Gharb area, Morocco

Abstract

The natural hydrogeochemical processes and the human activities are some of the factors that have direct effects on the groundwater quality. In this study, a hydrogeochemical assessment of groundwater was carried out to determine its chemical characteristics and its suitability for drinking in the region Sidi Allal Tazi- Morocco. The study has been carried out on 54 groundwater wells in the region under study. The groundwater samples were collected and analyzed during Dec 2016 - January 2017. The parameters examined were pH, electrical conductivity, total dissolved solids, calcium, magnesium, sodium, potassium, nitrates, ammonium, sulfate, chloride, carbonate and bicarbonate. The results have shown that the ammonium concentration in 96% of wells and nitrate concentration in 78% of them are much higher than the World Health Organization (WHO) standards, indicating the nitrogenous pollution. The electric conductivity in 50% of wells, chloride concentration in 46% and sodium concentration in 31% of them are relatively higher than WHO standards, indicating the mineral contamination, the Atlantic-Ocean water intrusion as well as the natural weathering reactions. The study has also revealed that other parameters are approximately in concord with the WHO standards. It showed that the dominant types of water in the study region are 59.26 % mixed Ca-Mg-SO4-Cl, 18.52 % Ca-HCO3 and 22.22 % Na-Cl type, indicating the gradual water-rock interaction. It is concluded that the groundwater of the study region has approximately the same geochemical evolution and medium quality for drinking.