Hydrogeochemical assessment and spatial analysis of groundwater quality parameters in North West of Morocco

Abstract

Global warming, population growth, agricultural intensification, and rising industrial productivity have affected groundwater quality. However, assessing groundwater quality enables us to understand the risk of contamination better and protect these natural resources in the long term. The objectives of this study are to evaluate the physicochemical parameters of groundwater for human drinking purposes in North West of Morocco and to identify their geogenic and/or non-geogenic origins through the use of graphical diagrams (Piper and Schoeller Berkaloff) and by GIS interpolation tools to recognize the main geochemical processes governing groundwater quality. For this purpose, the physico-chemical parametrs analyzed of groundwater in the Bouregreg basin and the southern part of the Sebou basin, using 51 water points in the study region’s rural area. Specific physicochemical water parameters (pH, TH, TAC, and electrical conductivity), cations (K + , Na + , Ca2+, and Mg2+), and anions (Cl−, NO3–, HCO3– and SO2−4) were measured and analyzed for human consumption. Piper diagrams and ArcGIS geoprocessing were used to identify groundwater hydrochemical facies and study the spatial distribution of estimated parameters concerning geology and anthropogenic factors. All the parameters measured were below the threshold values required by the WHO for human drinking water, except nitrates, recorded in one sample at a concentration of 88.75 mg/L. Piper and Schoeller Berkaloff diagrams show that strong acid (Cl−) and weak acid (HCO3–) appear considerably over the other acids (NO3– and SO2−4). In contrast, most sources show no cation dominance. The Calcium and magnesium chloride facies (43%) and Calcium-magnesium bicarbonate facies (35%) are the most facies presnent in this stydy. Geoprocessing showed that the chemical composition of the various sampling points is governed mainly by lithological diversity, except for S35, which showed an anthropogenic origin.