Assessment of bacteriological quality of groundwater from boreholes in Maroua (Far North Cameroon)

Groundwater (e.g. from wells and boreholes) represents an important source for water supply for populations in Maroua, Far north Cameroon. Although its consumption is being accentuated by the limited access to potable water, the quality of water from boreholes is unknown by the consumers. This study aimed at assessing the bacteriological quality of groundwater from boreholes in Maroua, in order to determine the impact of anthropogenic pressure and to measure the sanitary risks to which people who use them as drinking water sources are exposed. A total of 18 boreholes were chosen as sampling sites for bimonthly analyses (from October 2016 to January 2017). Microbiological analyses comprised the prevalence of total coliforms (TCs), Escherichia coli and Heterotrophic Aerobic and Mesophilic Bacteria (HAMB). Some physico-chemical parameters including temperature, pH, electrical conductivity, total dissolved solids (TDSs), salinity, dissolved CO 2 were measured to characterize these waters and to determine their influence on the bacterial flora. The results showed that the pH of the water of the 18 boreholes varied from 6.3 to 7.5 CU; the lower value of temperature was 25.9 °C and the higher was 31.2 °C. The values of electrical conductivity, TDSs and Salinity fluctuated from 171.5 to 1910.3 μS/cm, 119.4 to 1331.3 mg/l and 79.2 to 970.3 ppm respectively in the water samples of these boreholes. The concentration of dissolved CO 2 varied from 9.5 to 27.8 mg/l of water. From these results, 72.2% of analysed water samples were contaminated by the total coliforms and E. coli. The water contamination would be the consequence of the proximity of boreholes with latrines and domestic wastes. There is a need to educate the public about the quality of their water sources and the importance of clean and healthy surroundings near water sources and to implement household water treatment to improve the water quality and reduce waterborne diseases. Keywords : Bacteria, contamination, groundwater, sanitation.