The hydrogeochemical evolution and modeling of the Quaternary aquifer west of the River Nile, El Minia district

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Hydrochemical evaluation of surface and ground waters can be carried out using conventional and multivariate techniques. The main objective of this research is to investigate the water quality and determine the hydrogeochemical evolution and evaluation. The situation is further complicated by contamination with lithogenic and anthropogenic (agricultural and sewage wastewaters) sources and low plan exploitation techniques. The investigated aquifer is the Pleistocene, which composed of sand and gravel of different sizes, with some clay intercalation. The semi-confined condition was around the River Nile shifted to unconfined condition outside the floodplain. The groundwater flow is generally from south to north and diverts towards the eastern part, where large volume of groundwater is drained into the River Nile. Fifty-six, 11, five, and two water samples were collected from the Pleistocene aquifer, River Nile, Ibrahimia canal, and Al Moheet drain, respectively. The water was analyzed for major and trace elements. The prevailing hydrochemical processes are dissolution, mixing, and ion exchange. Four factors control the overall mineralization and water quality of the aquifer system. The factors from 1 to 4 are leaching of surface meteoric waters, agricultural activity (fertilizers and manures), lithogenic, and Fe–Mn oxyhydroxide phase, respectively. The dendrogram analysis reveals that four subclusters (A to D) match well with the geographic position of the River Nile. The major and trace element concentrations increase in subcluster D (far from River Nile) than those in subcluster A (beside River Nile). The saturation indices of calcite, dolomite, gypsum, and anhydrite were undersaturated, reflecting the dissolution condition in the aquifer system. The saturation index of CO2 was super saturated and increases due the western part, indicating the input of CO2 from different sources such as lithogenic, anthropogenic, and atmosphere. The TDS concentration is correlated well among SIO2, Al, Se, Cr, As, and Ni and correlated moderately among Fe, Mn, Pb, Cd, and Hg, reflecting the point and non-point contamination sources. The study highlights the description capabilities of conventional and multivariate techniques as effective tools in groundwater quality evaluation.