Nitrate Concentration in Drinking Groundwater Wells of Mekelle, Ethiopia (I)

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This paper examines the nitrate concentration in the Aynalem and Mekelle groundwater sources of drinking water for Mekelle city. A total of 15 water samples taken from the two well fields showed that significant differences in nitrate concentration. The lowest concentration 6.6 mg/l and highest concentration 46.8 mg/l were found in the Aynalem groundwater wells. The highest nitrate concentration among the 10 wells of Aynalem was found downstream of the well field in an animal feedlot. On the other hand, with exception of one, Mekelle well located upstream from the main area of the city with a level of 11.7 mg/l, the downstream wells contained concentrations of 54.6, 65.7, 97.5, and 209 mg/l. These samples exceed the maximum nitrate level of 50 mg/l for drinking water, a guideline set by the World Health Organization (WHO, 1996). Such anthropogenic sources as animal feedlots and municipal wastes are considered possible sources for the high concentration of nitrates in the Mekelle wells. Further study is needed to identify the sources of nitrate pollution in both groundwater well fields concentrating on geology, precipitation, land topology, soil profile, and its health impact on users.
日本雨水資源化システム学会の論文