Study of Groundwater in Northeast Cairo Area, Egypt

This paper presents a comprehensive hydrogeologic view of the Quaternary aquifer in north eastern Cairo area, Egypt. The hydrogeologic, hydrochemical and isotopic features of the aquifer are determined to assess the groundwater geochemistry and quality for different uses. The groundwater in the aquifer is shallow and flows towards the heavily pumping areas (cultivated and industrial areas). The concentrations of total dissolved solids (TDS) vary considerably in the aquifer, ranging from 225.6 mg/L to 1219 mg/L. Wide variations in the concentrations of major ions, trace elements, nitrate, δ18O and δ2H are detected, indicating the variation in the geologic and recharge conditions. This further indicates the effect of natural processes (weathering, dissolution and ion exchange) as well as anthropogenic activities on the quality of groundwater. Moderate levels of contamination with nitrate, aluminum and manganese are recorded in the groundwater below the cultivated area. The contamination is linked to the extensive use of fertilizers for agriculture and the leakage of wastewater from improper sewage system. The computed nitrate pollution index reveals that about 69.69% of groundwater is safe for drinking, while the rest of groundwater is unsuitable. The calculated water quality index indicates that about 78.79% of groundwater is safe for human consumption and the rest of groundwater is poor for consumption because of the contamination with the high levels of manganese, total hardness, pH, sulphate, aluminum, and nitrate. The contaminated groundwater needs to be treated before consumption. Hence, periodic groundwater quality checks are recommended.

Natural Attenuation Capacity Indicators for Groundwater Remediation to the Northeastern Cairo

The natural attenuation capacity of groundwater is considered to be an important factor for remediation purpose, it is also important for surveying suitability in the early phases of siting hazardous facilities. The present work has been devoted to explore the natural attenuation capacity of the groundwater system northeast Cairo. Some indicators (hydrogeological, hydrochemical and isotopic) have been insighted to explore the system retardability against contaminant dispersion. Groundwater flow and contaminant transport have been pointed out using GOD index which varied from 0.04 to 0.28 reflecting high protectability. The isotopic contents (18O, 3H, and 14C) showed a general comply with the GOD index and helped to delineate the sectors of high contaminate attenuation ability. Kelly index inferred significantly high adsorption potential on the aquifer clay content. The calcite and dolomite tend to precipitate on the aquifer contact providing a chance for specific contaminants to coprecipitate. The Eh-pH relation of the studied groundwater samples indicates high oxidation conditions and openness of the system. The attenuation capacity has been determined mathematically, it assumes the dispersive, advective, sorptive, and degradative processes acting on a solute in a one-dimensional flow system. The value of attenuation capacity increases by decreasing groundwater velocity and completely vanishes at a certain high velocity;determined for the relevant radioactive contaminants.