IntroductionGroundwater is the world's largest and most reliable source of freshwater, with nearly 80% of global inhabitants relying on it as a source of drinking water [1]. It is an essential source for domestic, industrial and agricultural activities. However, it is threatened with pollution and pure water is not available everywhere. Even the storage and availability of fresh water are not always secured. Also, the majority of irrigation and drinking water resources do not always conform to the international quality standards. This probably signifies the presence of anthropogenic or geochemical contamination. There are many reports worldwide indicating the contamination of groundwater or that it becomes at risk of contamination [2]. Failure to minimize water contamination can result in severe adverse effects on human health, animal and agriculture. Most diseases in human beings are caused by polluted water.Knowledge of hydrogeochemistry is a key to determining the origin of the chemical composition of groundwater, the interaction between water and rock and the process of groundwater flow [3 , 4]. Groundwater quality is naturally linked to the chemical properties of the aquifer's geology through which it flows. Thus, there is spatial variability in the quality of groundwater from one aquifer to another. Geology is not the only factor determining groundwater quality; anthropogenic factors also play an important role [5][6][7].
AbstractThe 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 TaziMorocco. 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-SO 4 -Cl, 18.52 % Ca-HCO 3 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.
