Determination of water quality from shallow wells of selected parts of Kitui County, Kenya

Abstract

Groundwater sources supply water for many people living in dry areas for agricultural, household purposes among others. Increased population has resulted in changes in land use, including deforestation, agricultural activities, and livestock rearing, among others. The residents of Kauwi and Zombe locations make use of agricultural chemicals and manure in their farms which are later washed in the water sources, degrading its quality. These human activities are likely to introduce contaminants in the shallow groundwater sources. In addition to these human activities there are also natural pollutants such as weathering of rocks, soils and minerals that also affect the water quality. The activities have potential to introduce contaminants in the groundwater sources which affect the water quality possibility of negative health implications to human beings and the environment. This study was undertaken to establish the physiochemical contamination of shallow groundwater sources. It looked at the elements that impact groundwater quality in Kitui County's Kauwi and Zombe locations throughout both the rainy and dry seasons. Samples were collected from randomly selected 30 shallow wells during the wet season of December 2021 and the dry season of October 2022 and analysed for physical chemical parameters using a portable laboratory kit in the field.From the findings, all parameters of interest complied with the recommended standards except for turbidity, chloride, calcium carbonate, nitrates and sulphates. Therefore, the shallow wells water quality in Kauwi and Zombe locations is suitable for domestic use except for some of the shallow well water points which contained high levels of sulphates, nitrates and turbidity. The study found significant spatial variation in the physical and chemical and characteristics of shallow groundwater resources in the areas (p ≤ 0.05) which were attributed to geologic materials and human activities carried out in the study area. Further, statistical significant temporal variations were also observed in the shallow ground water for both the wet and dry seasons. This was associated to surface runoff. The study results also revealed a significant statistical association between the water quality parameters in the studied areas which implies that the parameters have a similar source of origin in the environment. Based on the findings, the study proposes training programs to be conducted on farmers on applying the required quantities of farm in puts. The shallow wells should also be protected by fencing to restrict watering of animals. Finally, conducting regular water quality analysis on the shallow wells in the study area will provide vital information on water quality and help identify potential issues early. The results offer a baseline for future research on groundwater quality in semi-arid regions affected by both natural and anthropogenic factors. The study provides evidence to inform local water governance and regulatory frameworks. It calls for the development and enforcement of water protection policies, particularly in rural and agricultural zones. Policies should support capacity-building programs for local communities, focusing on safe agricultural practices and groundwater protection.