抽象的な

Contamination of many sources and irrigation canals by fecalbacteria in the piedmont of the middle atlas of beni mellal (Morocco), and physicochemical characteristics accompanying this contamination

El Hassania Saad, Mustafa Afdali, Ilham Saad, Lehacen Zidane, Mohamed Fadli, Allal Douira

With a geologic structure which facilitates the emergence of numerous springs supplying in drinkable waters several urban and rural towns and irrigating the neighboring lands, the piedmont of the mountain range of the city of Beni Mellal is situated between the plain of Tadla in the northwest and the alignment of the synclines ofOuedAbid in the Southeast. These sources are a little or not maintained at all; so they are exposed to various pollutions in particular those microbiological or physicochemical. In this work we have estimated the degree of contamination of eleven springs which are geographically distributed along a distance of 70 km. The physicochemical characteristics accompanying this infection were also determined. The results show that the majority of these sources or canals irrigation present fecal bacteria germs and the degree of the contamination is high in some of them. This contamination has an anthropological or animal origin in particular the use of fertilizer under the form of ‘manure’ and the excrements of cattle drinking or grazing near these sources. Besides, the physicochemical characteristics of the most polluted sources were different of the less polluted ones. Indeed, these last ones have relatively neutral pH, clear waters except those of Asserdoune, a low oxidability, an important hardness and alkalinity what is the opposite for the sources or the most polluted water of the seguias (irrigation canals).