Nitrate Pollution of Groundwater Based on GIS in the City of Daloa, West-central Cote d’Ivoire

Abstract

Doubt about the quality of tap water, due to its color, taste and unpleasant odors, forces a large part of the population of the city of Daloa (west-central of Cote d’Ivoire) to turn to spring and traditional wells waters whose quality is unknown. This study aims to assess the level of nitrate pollution of these shallow aquifers through 29 points including 9 spring and 20 traditional wells spread all over the city. Nitrate concentrations range from 2.5 mg/L to 301.1 mg/L, with 30% of the wells containing an excess of nitrate, beyond the WHO drinking standard (50 mg/L). The map of levels of nitrate concentrations in the city’s wells and springs shows the exposure of the populations of the old downtown neighborhoods to a high health risk due to the high pollution potential of nitrate in the water.