Groundwater Contamination as Affected by Long-Term Sewage Irrigation in Egypt

The use of treated sewage water for irrigating the desert sandy soil in Egypt has been practiced in Cairo. Abu-Rawash sewage farm is one that was established in 1944. The farm is irrigated by the flood system. Seepage water beneath the irrigated land is a result of the continuous use of sewage irrigation. Such seepage water, or so-called “groundwater,” is the only source for daily domestic use, including cooking, for the farmers. The physical and chemical characteristics ofs ewage irrigation water as well as fecal coliform and level of heavy metals werestudied extensively. The quality of the resulted groundwater was also investigated through 36 samples to investigate level of the level contamination. Results showed that the total dissolved solids (TDS) of groundwater samples vary from 306 to 9,808 mg/L. The minor constituents in these samples include phosphates, nitrates, nitrite, ammonia and sulfide, which exhibited high levels. About 88 and 92% of these samples were over the permissible level in terms of the biochemical oxygen demand and chemical oxygen demand, respectively. For the fecal coliform count, around 60% of the groundwater samples and 45% of the canal water samples were over the permissible limits for drinking water. The suitability of the studied groundwater for human risk consumption was, therefore, evaluated.