Vol.:(0123456789) 1 3 Euro-Mediterranean Journal for Environmental Integration (2019) 4:6 https://doi.org/10.1007/s41207-018-0087-4 ORIGINAL PAPER Evaluation of hydrogeochemical quality parameters of groundwater under urban activities. Case of Beni Mellal city (Morocco) Mohamed El Baghdadi 1  · Ismail Zantar 1  · Amal Jouider 2  · Samir Nadem 1  · Radouane Medah 3 Received: 16 March 2018 / Accepted: 30 November 2018 © Springer Nature Switzerland AG 2019 Abstract Tadla Plain is one of the most water-productive areas of the central Moroccan and also a fertile tract for agriculture. Our study is concerned with the Dir (Piedmont) aquifer in the sub-urban area of Beni Mellal. The aims of this paper are: (i) to identify some of the main hydrochemical processes controlling groundwater chemistry under the city of Beni Mellal and the impact of urban activities, (ii) to detect and understand the spatial variations of the occurring hydrochemical processes in order to localize areas with the most noticeably contaminated groundwater, (iii) to know the groundwater suitability for drinking, irrigation, and industrial purposes. Fifty-one groundwater samples during spring 2014 were collected and analyzed for physical and chemical groundwater parameters (electrical conductivity EC, pH, total dissolved solid TDS, T°, NO 3 − , SO 4 2− , HCO 3 − , Cl − , Na + , K + , Ca 2+ , Mg 2+ , and trace elements such as Ba, Li, Fe, Mg, Al, Cd, Cr, Cu, Mn, Ni, Pb and Zn). The overall hydrochemistry refects rock weathering with impregnation of anthropogenic impacts due to the urbanization and agricultural manures. The electric conductivity and the total dissolved solids have values more than the desirable limit of 750 µS/cm and 500 mg/l respectively in 49 and 59% of the total groundwater samples. The concentration of light metal does not exceed the recommended threshold with the following order Ca 2+  > Mg 2+  > Na +  > K + . Bicarbonate, nitrates, and chloride show contents under the desired guidelines contrary to the content of sulfate, which exceeds the threshold of Moroccan guide- lines especially in the central city zone. The abundance of anions is in the following order: HCO 3 −  > SO 4 2−  > Cl − > NO 3 − . The main hydrogeochemical process is dissolution and weathering from parent rock and cation–cation exchange. All calcu- lated parameter indexes are in concordance that Beni Mellal groundwater is excellent to good for irrigation purposes. The CaCO 3 supersaturation restricts the safe use of water for industrial purpose. For most of the trace elements, the measured concentrations were far below the standard values except Al and Fe in some samples, which exceed all guideline values. The use of PCA allowed extracting four principal components (F) using a Kaiser criterion and varimax rotated method, which explained 60% of the total variance. The highest F1 scores are concentrated in the central area, indicating a higher degree of water–rock interactions supplying elements with higher mobility to groundwater. Also, concentrated mobile elements can be reported on more anthropic activities. F2 scores showed a more scattered distribution compared to F1 scores with a concentration around peripheral zones of the city. Keywords Groundwater · Hydrochemistry · Urban · Anthropic activity · Heavy metal Introduction Groundwater is an important water resource for drinking and industrial purposes in urban areas (Barron et al. 2013; Backer 2009), mostly when available surface water resources are scarce. Many urban residents depend heavily on ground- water for drinking and domestic purposes (Sun et al. 2009). However, water quality becomes an important factor in determining the kind of usage for groundwater (Huang et al. 2016). This paper has been selected from the 1st Euro-Mediterranean Conference for Environmental Integration, Tunisia 2017. * Mohamed El Baghdadi m.elbaghdadi@usms.ma 1 Georessources and Environment Laboratory GEORE, Sultan Moulay Slimane University, 23000 Beni Mellal, Morocco 2 Wilaya Beni Mellal Khénifra, Beni Mellal, Morocco 3 Ofce National de l’Electricité et de l’Eau Potable, Branche Eau, Beni Mellal, Morocco