Physico-chemical and Bacteriological Quality of Boreholes and Evaluation of the Antibacterial Action of Disinfectants Used for the Microbiological Water Treatment

Abstract

Water pollution is currently at the top of the environmental agenda. In this study, the main objectives were (i) to assess the physicochemical and bacteriological quality of well and borehole water found in the vicinity of the University of Kinshasa and (ii) to assess the sensitivity of Escherichia coli and Enterococci strains isolated from various selected water points to disinfectants used at the industrial scale (Chlorine and chlorine dioxide) or in the household (Aquatabs) for the microbiological treatment of water. Three sites having wells or boreholes were chosen for sample collection, namely: The University of Kinshasa and its vicinity (Kindele and Kemi districts). The Physico-chemical parameters were determined in situ and then in the laboratory; and concerned the following indicators: pH, conductivity and turbidity. Moreover, the bacteriological quality was assessed by detecting the presence of faecal pollution indicator bacteria (E. coli and Enterococcus sp). The susceptibility of E. coli and Enterococcus sp strains to antimicrobials generally used for the microbiological treatment of drinking water was assessed by the dilution method on agar medium. The physico-chemical analyses showed that: (i) acid pH values in the different water points under study ranging from 6.3-6.5, (ii) conductivity and turbidity values range between 28.5 and 146 NTU. The bacteriological analyses showed that the Kemi district was the only water point which exhibited contamination with fecal pollution indicator bacteria. The strains of Enterococci and E. coli isolated from that well were highly sensitive to chlorine dioxide and Aquatabs and less sensitive to chlorine while the strains of E. coli are highly sensitive to chlorine dioxide and Aquatabs compared to the strains of Enterococci. In conclusion, we can recommend to these populations, the use of these compounds for water treatment precisely Aquatabs for household.