Quality of water and their ability to irrigate the area of El-Ghrous in the wilaya of Biskra (Algeria)..

The region of el-ghrous, has known an important agricultural rise which required the extensive use of inputs,where the risk to cause pollution of ground water in the region (mio-pliocene and lower eocene).these two layers are collected from boreholes of which there are 40 holes at the lower of the eocene and 13 atthe mio-pliocene.chemical analysis conducted in the laboratory of crstra ( november 2010), showed that the waterwas particularly rich in so42-, ca2 +, na+, k+, mg2+ and hco3-. in detail, we note that the sulfates are highconcentrations reaching values ranging from 1.43 g.l-1 to 3.14 g.l-1 in the water of themio-pliocene and 0.16 g.l-1 to 2.24 g.l-1 in the water from the lower eocene, which gives the water acalcium sulfate facies sometimes to sodium sulfate. the measured conductivity is still high for the waters of themio-pliocene with 5.62 ms/cm; however we notice relatively drop for the waters of the lower eocene(2.55ms/cm).these concentrations determined, led to the calculation of the sar. the latter combined with theconductivity to determine the suitability of ground water for irrigation.