LEVELS OF SELENIUM IN SELECTED RIVER, WELL AND BOTTLED WATERS IN ETHIOPIA BY MICROWAVE PLASMA-ATOMIC EMISSION SPECTROMETRY

Selenium is an essential trace element for many organisms, including humans, but it is toxic at higher level than homeostatic levels. Both selenium deficiency and toxicity are problems around the world (specially in China, India, USA). The level of selenium in selected waters of Ethiopia (including Akaki Kality river and some of its tributaries such as Kebena, Saris Abo, and Estifanos areas; bottled waters like Yes, Aqua Safe and Gift; well waters like Ziqualla Wogem, Akaki Kality and Ferensay Legasion; and tap water at Arat Kilo) were determined by microwave plasma-atomic emission spectroscopy after wet digestion and acidification. The levels selenium determined (mu g/L) were 7.0, 3.1, 6.4, 3.9, 6.3, 5.0, 5.4, 0.66, 4.2, 6.3, and 2.0, respectively. The percentage recovery of Se was found to be 95.2% which is in the acceptable range. The ANOVA result showed that there is a significant difference between the mean levels of selenium in the river, well and bottles waters. The results obtained in this study were compared with the permissible limit (10 mu g/L) set by Ethiopian Standards Agency and the tolerable level set by WHO (< 40 mu g/L). Thus the levels of selenium detected in this study are within the recommended limit.