Potentially toxic elements in some fresh water bodies in Ethiopia

Abstract

A total of thirty three water samples were collected from Tinishu Akaki River, Lake Awassa, and Lake Ziway, Ethiopia. Multi-element determination of trace elements (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Ag, Cd, Sn, Hg, and Pb) in water samples was carried out by inductively coupled plasma-mass spectrometry after acidification with 1% HNO₃. The concentration (in µg L⁻¹) of the elements were in the range of 1.0–19, <0.42–83, 1.1–1580, <45–1760, <0.11–2.0, 0.43–13, 0.77–13, 6–300, <0.94–2.0, <0.3–1.5, <0.012–0.63, 0.13–4.8, <0.29, and 0.2–7.2 for V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Ag, Cd, Sn, Hg, and Pb, respectively. The concentrations of all the quantified elements, with the exception of Mn, were in the range of the permissible limits of the Ethiopian, European Community, and World Health Organization for both drinking water quality guidelines and irrigation water guidelines. The accuracy of the method was validated by analyzing trace elements in water standard reference material (SRM 1643e). The measured values of trace elements in the SRM agreed well with the certified values at the 95% confidence level.

Keywords:

• trace elements
• water
• inductively coupled plasma-mass spectrometry
• Tinishu Akaki River
• Lake Awassa
• Lake Ziway

Acknowledgments

This work was supported financially by the African Laser Centre (project no. LHEAB01 Task 1113). The funding from Rental Pool Programme (project no. LREEO00) is duly acknowledged. This research is part of a PhD dissertation, so financial assistance by the Office of Research and Graduate Programs of Addis Ababa University, Addis Ababa, Ethiopia is gratefully acknowledged. Moreover, the authors acknowledge Department of Chemistry of Addis Ababa University, Addis Ababa, Ethiopia and Department of Chemistry of Tshwane University of Technology, Pretoria, South Africa for allowing us to use the laboratory facilities. Kebede Nigussie Mekonnen acknowledges Mekelle University, Mekelle, Ethiopia for the partial financial support (with project registry number CNCS/RB/21/2010).