Deterioration of Groundwater Quality in the Area between El Saff and El Khashab Canals, South Giza, Egypt

Abstract

Groundwater is a major important source of water that is vital for human survival and development. Therefore, any changes in groundwater chemical composition will cause its deterioration and impact on its applicability in drinking, agricultural and industrial processes. So, the objective of this work is the study of the deterioration of the groundwater quality in the area between El Saff and El Khashab canals using the integration between the chemical and microbiological data, remote sensing and GIS techniques, in addition to geochemical modeling, and Piper diagram as well as statistical analyses. A total of 87 and 104 water samples were collected during the two periods 2016 and 2022, respectively, from surface water (irrigation canals “El Khashab, El Hager and Masjid Musi alqabliya canals”, and El Saff canal for wastewater) and groundwater (Quaternary and Pliocene aquifers). Chemical analyses were carried out to determine the concentrations of major and minor constituents as well as the trace elements in the collected water samples. Also, microbiological pollutants analyses for some selected surface water and groundwater samples were done. The obtained results revealed that the average values of salinities of El Saff canal for wastewater and irrigation canals water samples in the study area
increased from 886 to 2034mg/l and from 843 to 1059mg/l by time from periods 2016 to 2022, respectively. Also, the concentrations of sodium, sulfate and chloride in the irrigation canals water samples increased by time from period 2016 to 2022. The average values of the salinities of the Quaternary and Pliocene groundwater samples ranged from 1588 to 1850mg/l and from 2800 to 3820mg/l during the periods 2016 and 2022, respectively. The average values of calcium, sulfate and chloride concentrations showed an increasing trend during time from 2016 to 2022 for both the Quaternary and Pliocene aquifers, and the direction of the increase followed the same trend of salinity increase. The piper diagrams showed that the Quaternary and Pliocene groundwater samples in the study area that affected by El Saff canal for wastewater increased by time from 2016 to 2022. The geochemical model indicated that the maximum mixing ratios of the wastewater of El Saff canal with the Quaternary and Pliocene groundwater samples ranged from 65% to 66% for the Quaternary aquifer and from 72% to 96% for the Pliocene aquifer in the study area. The average values of nitrate and boron concentrations showed a valuable increasing trend during time from 2016 to 2022 in irrigation canals and for both the Quaternary and Pliocene aquifers. The total and fecal coliforms bacteria count in the surface water and groundwater resources in the study area increased by time from 2016 to 2022. Cluster analysis results cleared that the deteriorated groundwater samples in the study area increased by time from 53% of Quaternary and Pliocene aquifers in period 2016 to 73% in period 2022, respectively. The suitability maps revealed that only 23% and 16% of the groundwater samples in the study area during periods 2016 and 2022, respectively, are suitable for human drinking, and that the suitable groundwater for human drinking decreased by time from 2016 to 2022. Staff diagrams indicated that only 27% and 22% in period 2016, and 19% and 17% in period 2022 of the Quaternary and Pliocene groundwater samples, respectively, are good water for irrigating all types of crops, as well as the good water for irrigation decreased by time from 2016 to 2022. Finally, the chemical and microbiological data, as well as the Piper diagram, geochemical model and cluster analysis results confirmed that the deterioration of the groundwater samples in the study area increased by time from 2016 to 2022.