Water Quality Evaluation of Hand-dug Wells in Ibadan, Oyo State, Nigeria

Abstract

In many countries around the world, including Nigeria, access to potable water has become a mirage. Exploitation of groundwater through the construction of hand-dug wells is a major source of drinking water for majority of the populace. The need to assess the quality of water from this source to ascertain the role of well construction methods has now become imperative because of the health impacts on individuals. Random surveys of three classifications of hand-dug wells were done between June and October 2010, in Ibadan, Nigeria. One hundred and one (101) hand-dug wells were selected. A standard form was used for capturing data used for the classification of the wells into protected, semi protected and unprotected. Standard laboratory methods were employed for the analysis of electrical conductivity, pH, Temperature, Chlorides, Nitrate, E. coli and Total Coliform Count. Results show that nitrate concentration, E. Coli and total coliform counts are more pronounced in wells that are installed close to domestic refuse waste, abattoir, pit latrine, stagnant water, and drainages. The pronounced concentrations decreased with increasing distance from the pollution sources irrespective of well classification. Protected wells gave better water quality relative to semi-protected and unprotected wells. The paper recommends regular monitoring of groundwater quality, abolishment of unhealthy waste disposal practices, and regulation of self supply well construction and design.