Assessment of Groundwater Quality from Aquifers in Garissa County

Abstract

Water currently consumed by rural residents in Kenya far exceeds drinking water guideline values proposed by the World Health Organization. The basement and alluvial formations are known to exhibit poor water quality, with predominantly slightly saline water at greater depths especially in areas where there is no groundwater movement. Wells are prone to pollution due to lack of well protection and that in effect compromises water quality. The main objective of this study was to assess the quality of water sampled from pans and wells in Garissa County. Representative samples were collected according to internationally approved methods of sample collection, transportation, and testing and data analysis. 40 boreholes, 45 water pans, various points of the river Tana, shallow wells and springs were sampled across the County and physicochemical and biological parameters ascertained. Results obtained identified high total water hardness, total alkalinity, fluoride, chloride and turbidity. Some water sources in sampled area had high fluoride, high arsenic levels (16 μg/l), pH (8.78) and conductivity (22000 μs/cm), exceeding WHO limits of 1.5 mg/l fluoride, 10 μg/l for arsenic, 6.0 - 8.0 for pH and 2,500 μs/cm for conductivity by WHO (2013). The study concluded that accessibility to good quality drinking water is hampered by the presence of pollutants in some areas.