Prediction of nitrate contamination trends of groundwater in Al-Butana region of Sudan

It has been documented that the increase of population in a confined area increases the risk of nitrate ion (NO3-) contamination where modern sewage system is absent and traditional latrine holes are spread. In this study the NO3- levels of 209 well water samples belonging to previous construction analyses (CA) and a total of 121 well water samples belonging to the current study analyses (SA) in Al-Butana region of Sudan were statistically analyzed and located using the geographical information system (GIS). Cross comparison among the CA and the SA data were investigated and graphed. The GIS-map indicated that the nitrate ion levels > 50 mg/l were found in the central and southern part of the study area. Nitrate ion levels in the CA revealed that only 4 boreholes (1.91%) exceeded the maximum permissible limit of 50 mg/l set by SSMO, WHO and EEC standards and guidelines while none of the investigated boreholes in the SA exceeded the maximum adopted level (MAL) of 50 mg/l. Depicted trend graphs revealed that NO3- increases, gradually, over time almost in all parts of the study area as a result of the wide spread of traditional latrine holes and septic tanks system. Some boreholes are expected to reach the MAL within few years. The gradual increase in NO3- indicates that NO3- contamination may constitute a real forthcoming problem and threatens groundwater quality of the aquifer(s) of the study area.