Hydrochemical and seasonal assessment of groundwater and suitability analysis for agricultural utility in southern Lake Chad Basin, Northern Cameroon

Arid and semi-arid regions have experienced rapid population growth during these last decades. Groundwater is used for various socio-economic activities because of its long-term availability in nature. The main income-generating activity for these populations is agriculture. To do this, it is essential that the water available is of good quality. This work focuses on explaining ions (major and trace elements) origin and evaluating water aptitudes for agricultural purposes. Two field campaigns were carried out in May and November to collect surface and groundwater samples. During these campaigns, water table depth, pH, temperatures and electrical conductivity were measured in boreholes and watercourses. Groundwater and surface water were sampled to assess major ions and trace elements contents. Four chemical facies (HCO3-Na, HCO3-Ca, SO4-Na, SO4/Cl-Ca) have been identified in groundwater and only one (HCO3-Ca) in surface water. Groundwater is much more mineralized than surface water. Ions contained in groundwater have a double origin (natural and anthropogenic). Surface waters can be used for irrigation needs unlike the groundwater. All samples are usable for irrigation for MR, 40.74% for KI, 59.26% for Na%, 70.37% for RSC and 96.30% for SAR. In addition, groundwater with very high levels of Mn, Mo and U are unsafe for irrigation.