Groundwater pollution by nitrates: the case of Massili Sub-basin in Burkina Faso

Abstract

The Massili sub-basin is located in the central zone of Burkina Faso and covers an area of 4,525 km². It is experiencing rapid population growth and the development of socio-economic activities, which are sometimes a source of nitrate pollution of groundwater. The aim of this study was to use ion chromatography to analyse 70 water samples from wells and boreholes located in the Massili sub-basin.The results showed that 10% of the water samples had nitrate concentrations above the WHO drinking water standard of 50 mgl-1. These were Wapassi Alaré (51.46 mgl-1) ; Loumbila Bangrin (F2 57.48 mgl-1) ; Bazoulé F1, (57.59 mgl-1) ; KF1, (58.86 mgl-1); Silmiougou F5, (86.11 mgl-1) ; KB F2, (90.22 mgl-1) and KBS2 P7, (98.88 mgl-1).
In addition, the water from some facilities (16%) needs to be monitored for nitrate concentrations. Consumption of nitrate-polluted water may be the cause of the development of methemoglobin, particularly in infants. Principal component analysis showed that human activities are the cause of nitrate pollution in the water samples analysed.