Hydrochemical studies and evaluation of groundwater quality of the Quaternary aquifer at Faquss, Al Sharqiya Governorate, Egypt

Abstract

The Quaternary deposits represent the main groundwater aquifer in the study area. During the last few years, the problem of groundwater contamination has been intensified mainly due to natural and human-related factors. The present work aims to study the hydrochemical characteristics and quality assessment of shallow groundwater of the Quaternary aquifer at Faquss district. To achieve that, 16 groundwater samples were collected and analyzed for major ions, trace elements, and microbiological analysis. Constructions of water level map of the Pleistocene aquifer and distribution maps for different ions in groundwater were made by surfer software. Statistical analyses for water quality parameters were carried out. Results indicate that most of the studied area is characterized by fresh water (TDS < 1000 mg/L) with low contents of K, Na, Mg, Ca, SO₄, and Cl reflecting the suitability of ground water for drinking. High contents of TDS, Na, SO₄, and Cl are recorded at the northeastern parts of the area; this refers to the existence of local pollution sources resulting from the infiltration of domestic, agricultural, and industrial wastes in the intensive populated area. The concentrations of trace elements (chromium, copper, cadmium, etc.) in groundwater are within the acceptable limits for drinking and domestic uses. Iron and manganese are over the acceptable limits in most of the area and the groundwater is unsuitable for drinking. Low contents of iron and manganese are recorded at the north, while aluminum contents are over the acceptable limits at the same site. The results of bacteriological analyses indicate the existence of E. coli bacteria in most of shallow wells ranges between 4 and 800 ml. So, shallow groundwater should be chemically treated before drinking. Generally, the groundwater in the studied area is suitable for irrigation, except 19% of wells suffer from sodium hazards. The ratio rNa/rCl varies between 1.012 and 1.56 in most groundwater samples and indicates the continental origin of groundwater in the study area. The ratio r (K + Na)-rCl/rSO₄ reflects either Na₂–SO₄ water type (in 75% of groundwater samples) or NaHCO₃ water type of shallow meteoric origin (in 25% of groundwater samples). The presence of Na₂SO₄ water type in deep meteoric water genesis at shallow depth is associated with sulfate salts (MgSO₄, and CaSO₄) which formed more than 25% of salt combination might reflect the influence of anthropogenic activities. The dominant process determining the water composition is evaporation.