Physicochemical and microbiological assessment of the drinking water sources from Manoka Island, Cameroon

ABSTRACT

Water is a natural resource essential to life, but its quality is jeopardized by pollution from several sources, hence the need to contribute to improving its quality. The present work was conducted to assess health risks related to sources of drinking water used by inhabitants of Nyangadou village in Manoka Island, Cameroon. A descriptive and analytical study of 41 randomly selected households was carried out in order to get an idea of the health risks associated with drinking water. Water samples were collected from functional wells and boreholes and analyzed in order to determine physico-chemical parameters and microbiological contaminants, using the standard methods described by APHA and AWWA. Among the 41 surveyed households, 31.72% treat water before consumption while 68.28% do not treat it and no household had latrines. The physicochemical analysis showed that the water samples analyzed were contaminated to varying degrees by organic and inorganic matter. The average nitrite (NO^2-) concentration in well water is 19.1 ± 0.7 mg/L while ammonium (NH4⁺) contents are 27.15 ± 0.02 and 0.49 ± 0.07 mg/L in well and borehole water samples respectively. The biochemical oxygen demand (BOD) and chemical oxygen demand (COD) are very high in well water (938.33 ± 0.6 mg/L) and borehole water (1114 ± 0.06 mg/L). The microbiological analysis showed that the value of total germs is 184 and 14 CFU/100 ml in well and borehole water samples respectively. These different values of the chemical and bacteriological parameters found in well water samples greatly exceed the WHO standard values. These results indicate that well water is polluted with characteristics like high levels of organic matter, inorganic matter, faecal coliforms and total germs. Consequently, this well water is unhealthy for direct consumption. Appropriate measures shall be taken for the disinfection of such water before its use.

Keywords: Well water, borehole water, physicochemical parameters, households, water quality, Manoka.