Assessment of groundwater(Boreholes) quality in Nyagatare District, Eastern Province of Rwanda

Abstract

Underground water is an important natural resource serving as a reliable source of drinking water for many people worldwide, especially in developing countries. Underground water quality needs to be given a primary research and quality control attention due to possible contamination. It has limited number of surface water resources while groundwater exploration was favors in Nyagatare district as boreholes. They were not only the chemicals from fertilizers through the agriculture’s activities and microbes from livestock but also there were not spatial distribution of boreholes water quality parameters concentrations in Nyagatare district. This study was therefore designed to determine the physico-chemical and bacteriological quality of borehole water and map prediction in Nyagatare district. The study was conducted in nine sectors in Nyagatare district. The bacterial load of the water samples was determined using standard microbiological methods. Physicochemical properties including pH, total alkalinity, temperature, turbidity, total dissolved solids (TDS), electrical conductivity, total hardness, calcium hardness, magnesium hardness, total iron, Manganese, chloride ion, fluoride, Nitrate and sulfate were determined. The values obtained were compared with the WHO. The Kriging Interpolation methods was adopted by using Arc GIS 10.8 to analyze the geostatistical for interpolation of point-based distribution of measured groundwater quality. The recorded pH, total turbidity and EC ranges were 4.99– 7.36mg/l, 0.99 to 19.0NTU 45.16157.25 µS/cm respectively. Furthermore, the mean concentrations of iron, calcium, magnesium, chloride, fluoride, sulfate, nitrate and manganese were 0.13, 49.24, 15.49, 37.45, 1.82, 99.4, 5.60, 0.03 respectively. In addition, the mean total hardness value was found to be 121.76 mg/l whereas Only 20% of the water samples tested positive for faecal coliforms. Physical, chemical and biological parameters assessed with Predicted maps Ca2+ and Mg2+ Hardness, turbidity, Nitrate, fluoride and feacal parameter resulted at the highest values exceeding the WHO limit from laboratory and Geospatial Analysis water samples 14 (66.67%) were classified as “excellent and 7 (33.33%) Good water. Therefore, all the water samples without the presence of coliforms were considered suitable for human drinking. This calls for regular monitoring and purification of boreholes to ensure good water quality.