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The contamination of freshwater resources with various organic and inorganic contaminants is still a major problem in many parts of the world, especially in developing countries in which the poor water quality continues to pose a serious threat to human health. In this study, the assessment of groundwater quality was performed in the municipality of Bumbu (Kinshasa, Democratic Republic of the Congo) according to the seasonal variation. Water physicochemical parameters [pH, electrical conductivity (EC), dissolved oxygen and soluble ions (Na ? , K ? , PO 4 3-, SO 4 2-, NO 3 -, NO 2 -)] and faecal indicator bacteria (FIB) including Escherichia coli (E. coli), Enterococcus (ENT) and Total coliforms (TC) were analysed. Except for EC and NO 3 -, the results revealed low concentration of other water physicochemical parameters, which are below the recommended limits, according to World Health Organization guideline for drinking water. Additionally, the result showed high concentration of FIB reaching the values of 1.6 9 10 4 , 1.5 9 10 4 and 9.0 9 10 5 CFU 100 mL -1 for E. coli, ENT and TC, respectively. The pollution was substantial in wet season compared to dry season. PCR amplification for human-Bacteroides indicated that more than 90 % of bacteria were from human origin. Our results highlight the potential human risk associated with the exposure to water contamination from wells due to the high level of NO 3 -, EC, E. coli and ENT in both dry and wet seasons. The approach developed in this study helps provide a better understanding of the physicochemical and microbiological pollution of wells in large cities characterized with lack of wastewater and sanitation facilities.

In many suburban municipalities of developing countries, the household drinking water comes mainly from groundwater including, wells, streams and springs. These sources are vulnerable because poor hygienic conditions and sanitation prevail causing persistence and recurrent waterborne diseases. In this research, a survey study on water resource use and an epidemiological survey of waterborne diseases were conducted among users of water points and medical institutions in suburban communes of Selembao and Kimbanseke (Kinshasa, the Democratic Republic of the Congo). In addition, physicochemical (temperature, pH, O2, electrical conductivity, and soluble ions: Na+, K+, PO43−, SO42−, NO3−, NO2−) and bacteriological (FIB: faecal indicator bacteria) analyses of water from 21 wells and springs were performed according to the seasonal variations. FIB included Escherichia coli (E. coli), Enterococcus and Total Coliforms. The survey results indicate that more than 75% of the patients admitted to local medical institutions between 2016 and 2019 are affected by waterborne diseases, including typhoid fever, amoebic dysentery, diarrhoea, gastroenteritis disorders and cholera. Except for NO3− in some sites, the water physicochemical parameter values are within WHO permissible limits for drinking/domestic water quality. On the contrary, the results revealed high FIB levels in water from unmanaged wells and springs during rainy and dry seasons. The microbiological pollution was significantly higher in the rainy season compared to the dry season. Interestingly, no FIB contamination was observed in water samples from managed/developed wells. The results from this study will guide local government decisions on improving water quality to prevent recurrent waterborne diseases.

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