NITRATE CONCENTRATION AND GROUNDWATER VENERABILITY IN TYPICAL SHALLOW BASEMENT AQUIFERS AROUND KEFFI AREA, NORTH-CENTRAL NIGERIA

Keffi 414 environs is characterized لا near surface outcrops o f underlying basement rocks and s h a lli overburden thickness.The study assessed tire potential ofnitrate-nitrogen (NOj-N) contamination o f surface and groundwater within the study area. Thirty-two groundwater samples and four stream samples were collected from different locations across the study area and analysed for their NO٢N concentration. Groundwater sampling were restricted to well-covered shallow hand-dug wells SHW}, medium depth hand pumps (MHP) and motorised boreholes (DMBH). In all the groundwater samplesanalysed,12.5°/oofthemexhibitedN03-Ncontentshigherthan O h g L 1 and 60% o f the samples collectedfrom the agricultural fields contained N o ٢N higher than 0 .05mgL؛ in contrast to 20% of samples from residential areas. Results also revealed an inverse relationship between the NOj-N concentrations and the depth o f the sampling aquifers (SHW>MHP>DMBH). All of the analysed samples contained NO3-N load 1656 than thefixed threshold limit by WHO (2006١ for drinkingpurposes of below lOmgi;1, thus, rendering the waters safe for drinking purposes.