Surface water pollution risk assessment of wadis, Mekerra and Saïda, in the North-Western of Algeria

Considered as the main stream of hydrographic network Mactaa’s basin, in west highlands Algeria, both wadis, Mekerra and Saïda, are affected by pollution which is generated anthropogenic activities. Makara Saïda wadis cross urban areas Sidi-Bel-Abbes respectively, constitute a real problem human safety. In order to identify state on these samples have been collected during three periods time (June 2011, July 2012 April 2013) goal characterize physico-chemical bacteriological quality surface water.Results obtained describe clearly existence chemical organic at high levels calcium, magnesium, chlorides, nitrates, nitrites, phosphate, DBO5 dissolved oxygen. The evaluation index (OPI) confirmed that there pollution, upstream, increases with water passage towards cities (OPI).The analysis results show presence contents faecal bacteria contamination (total coliforms (TC), (TC) streptococci(FS))principally wadi Saïda. relationship between FC/FS justifies predominance origin than animal source contamination. While, determination microbiological (MQI), for each wadi, confirms degradation mainly area.