Accepted 9th, December, 2014
This retrospective study aimed to investigate the spatial variation of nitrate level in the drinking water sources found in Ethiopia. In the study, the Ethiopian Health and Nutrition Research Institute water quality database from the year 1993 to 2007 was used. The results of the water sample indicated that nitrate concentration were varied from below 0.00mg/l to 1295.00mg/l. Nationally, 15.3 % (n=186) of the wells, 10 % (n = 33) of the springs and 12.4 % (n=21) of the taps had nitrate concentration exceeding the threshold value of 20mg/l and 5.7 % (n = 70) of well water and 2.7 %( n = 9) of spring water samples had nitrate concentration higher than 50mg/l. The average nitrate concentration in the well waters exceeding the WHO guideline was observed in Dire Dewa (104.8mg/l) and exceeding the threshold value were found in Somali (37.0 mg/l), Afar (34.9 mg/l), Harari (26.3 mg/l) and Addis Ababa Regions (20.5mg/l). Nitrate in all the spring water was below the threshold value except Dire Dewa and Harari regions. In those water sources with high nitrate concentration, management action should be taken to protect the water from further contamination.
Keywords: Nitrate, drinking water, well water, spring water, tap water