Hydrogeochemical Analysis of Groundwater in the Sawla-Tuna-Kalba District of the Northern Region of Ghana

Abstract

The climate of the Sawla Tuna Kalba District is the tropical continental type where only one rainy season in a year, occurs between early May and late October this makes surface water resources insufficient in the area. Groundwater is the main water supply in this region the utilization of groundwater for various purposes is common. In this part of northern Ghana, groundwater serves as a major source of freshwater for domestic and agricultural purposes. This study investigated the quality of groundwater from 87 boreholes in the Sawla-Tuna-Kalba District of the Northern Region, to promote and enhance the proper utilization of the resource. Samples were collected and analyzed for various water quality parameters to evaluate its usefulness for domestic and agricultural use. Results indicates that groundwater in the study area is generally fresh and hard. It was found that majority of samples belong to the Ca- Mg-HCO3 hydrochemical facies. Sodium Adsorption Ratio (SAR) for all groundwater samples in the district ranged from 0.175-2.70 (mean 1.00), implying that all the boreholes samples had excellent water that could be used for irrigation. This was confirmed by analytical data plot on the US salinity diagram which illustrated that majority of groundwater samples fall in the field of C2S1; indicating medium salinity and low sodium water. The total hardness (TH) values ranged from 57.94 to 641.2 mg/l with an average value of 187.1 mg/l. The classification of groundwater based on (TH) shows that a majority of the samples fall within moderately hard to hard water category. Though many of the analysed parameters fall within acceptable range and thus most of the boreholes have water which are chemically suitable for drinking, a few recorded total iron, manganese, lead, arsenic and fluoride concentrations above permissible WHO levels, suggesting some concern in terms of potability, especially since such water sources are extensively patronised by inhabitants for drinking and agricultural purposes.