Evaluation of the suitability of groundwater quality for drinking and irrigation purposes: a case of gimbi district

Abstract

The quality of groundwater depends on various chemical constituents and their concentration, which are mostly derived from the geological data of the particular region. Water quality degradation is one of the major environmental problems of these days. Contamination of surface and groundwater is the most serious problems affecting the health of the population. The study was conducted to evaluate the suitability of groundwater quality for drinking and irrigation purposes in Gimbi District, Oromia National Regional State, Ethiopia. The study was to determine the basic Physical, chemical and biological parameters of groundwaterand to evaluate the suitability of the water for drinking and irrigation purpose. Electrical Conductivity, Sodium Absorption Ratio, Soluble Sodium Percentage, Residual Sodium Carbonate, Magnesium Hazard and Kelley’s Ratio were determined for irrigation suitability assessment. Twelve samples were collected from hand dug boreholes, hand dug wells and protected spring by purposive sampling technique and analyzed for various parameters. Interpretation of all water chemistry data were carried out using Aqua Chem software (Version 4.0), Origin Pro 8 and Microsoft excel (Version 2007). The analyzed data was presented by using table, graphs and piper diagram. Compared with WHO guideline values for drinking water, temperature range 23.60 to 26.18 0C exceeds150C, pH range 4.71 to 6.20 fell below the range of 6.5 to 8.5). Turbidity(1.06 to 10.33 NTU), which indicates that higher levels of turbidity than the WHO recommended limit of 5 NTU especially in locations S2, S6, S9, S11, and S12. EC (38.67 to 233 μS/cm), which was less than the WHO recommended limit of 250 mg/l. Manganese ranging from 0 to 0.31mg/L and low concentration levels than WHO prescribed limit of 0.1 mg/l at all locations except S10 and S12. Higher concentrations of iron than the WHO stipulated limit of 0.30mg/L in locations S2, S3, S5, S8, and S12. The bacteriological analysis also revealed that all the water sources contained high Fecal and Total Coliform counts ranging 17 to 396 and 284 to 4586 cfu/100 ml respectively. This implies that the Consumption of water contaminated from water sources may cause public health problems.