Groundwater contamination in the Niamey urban area, Niger
ABSTRACT: Many residents from peripheral areas and poor city dwellers are usually reliant on untreated drinking water for their daily consumption and household needs. Such is the case of Niamey aquifer with its three main aquifers (discontinuous basic aquifer, alluvial aquifer and continental terminal aquifer) relatively tapped for water supply. Research has confirmed that the groundwater of the Niamey urban area is heavily polluted chemically and bacteriologically. High nitrate, chloride and sulphate concentrations as well as high bacterial counts of different genera (total count, faecal coliforms, feacal streptococci) indicated that this type of pollution was of faecal origin. This does not exclude the possible contribution of other pollution sources. The main pollution sources identified were the numerous pit latrines and septic tanks located in close proximity to domestic, industrial effluents, and numerous illegal domestic disposal sites in the urban areas, run-off waters in the rainy season, and finally a substandard sanitation network. This poses a serious problem, due to the volume of groundwater consumed and its negative effects on human health. Research to better characterise the pollution sources and transport mechanisms will facilitate more effective protection of the water resource, and the urban environment as a whole.