éTUDE DES CARACTERISTIQUES PHYSICO-CHIMIQUES ET BACTERIOLOGIQUES DES EAUX DE QUELQUES PUITS A GRAND DIAMETRE : COMMUNES DE PARAKOU ET TCHAOUROU AU BENIN

Physico-chemical and bacteriological analyses were performed on water samples taken from ten (10) large diameter wells realized by Caritas-Benin. The results showed that 80% of water samples are moderately mineralized while 20% are less mineralized. In Tchaourou (Tchalla and Bakperou localities), 20% of the water samples contains nitrates which concentrations were respectively 54.12 mg/l and 45.44 mg/l for ATL3 and Abp4 wells. Significant bicarbonate content was also observed in all underground water samples in this district reached respectively 122 mg/l (Abr2) and 128.10 mg/l (Ado7) for must important. This could be explained by soil enrichment, by fertilizers and organic matter mineralization in these areas, the nature of the land crossed by the water and the impacts of human activities. In bacteriological terms, these waters were found be generally fecal contaminated with thermotolerant coliforms in all water samples in concentrations ranging from 3.102UFC (Akk6) and 30.102UFC/100ml water (Akb10). These values exceed limits recommended by the standard of Benin and the Guidelines of the World Health Organization. Poor hygiene and sanitation may be the cause of such chemical and microbial pollution recorded.