USE OF HYDROCHEMISTRY AND ISOTOPES TO STUDY THE ENVIRONMENTAL POLLUTION OF WATER RESOURCES AND ITS RELATION WITH GROUNDWATER AQUIFERS IN WESTERN REGION OF GREATER CAIRO

Abstract

The aim of this study is to assess the water quality of surface and groundwater in the western part of Cairo and to estimate the sources of pollution as salinisation, nutrients trace elements and microbiological activity as a result of re-use of drainage and sewage water for irrigation. In the studied area fresh water problems arise from the limitation of water resources, high degree of use and fast demographic growth, human activities and the presence of two sewage stations (Zinen and Abu-Rawash stations) for collection and treatment of wastewater of Giza area. The poorly treated effluents that discharge from these stations to Zenin and Barakat drain or mixing with fresh canals lead to direct pollution to the surface and groundwater in this area. The studied area is located in the western region of greater Cairo at latitudes 30° 00' and 30° 15' N and longitudes 31 o 00' and 31° 15' E. About 97 of surface water samples were collected from canals and drains and groundwater samples from the main aquifer system in the area (Quaternary aquifer). The estimated values of total dissolved solid for most surface and groundwater samples do not exceed 1000 mg/1 expect 12% of water samples have salinity>1OOOmg/1. This increase in salinity could be attributed to the ion exchange process between Na- Ca as a result of water- rock interaction, or from the recycling drainage water containing excess of fertilizers that used for cultivating practices. The predominant water types of surface and groundwater samples are NaHC03 and Na2S04 representing meteoric and mixed water type. Few numbers of groundwater samples have MgCh (marine water type), these samples are located in the east and middle parts of the studied area.