DETERMINATION OF HEAVY METALS IN CEMENT DUST, TOP SOIL AND TEFF AROUND HABESHA AND MUGHER CEMENT FACTORY, OROMIA REGIONAL STATE, ETHIOPIA

Abstract

In this study, the level of selected heavy metals in cement dust, soil and teff samples collected from around Mugher and Habesha cement factories, Ethiopia were determined using flame atomic absorption spectroscopy (FAAS). The collected samples were digested using properly optimized acid digestion using a mixture of 5 mL HNO3:1 mL H2SO4:1 mL HClO4 at 200 oC for 2 h for the cement dust; 3 mL HNO3:4 mL HClO4:1 mL H2O2 at 300 °C for 3 h for the soil and 5 mL HNO3:3 mL H2O2 for 1:30 h at 200 °C for the teff samples. The mean concentrations of metals determined (mg/kg) were in the ranges of Cu (450.26-471.79), Zn (1096.75-1103.10), Mn (3316-3419), Cr (242-404), Fe (31846-33836), Ni (1524-1727), Co (2492-2517), Cd (20.4-26.1), Pb (255-649) for cement dust; Cu (294-333), Zn (194-330), Mn (498-521), Cr (330-450), Fe (5283-5392), Ni (1138-3719) and Co (1439-1516) for soil, Cu (85.6-89.4), Zn (314-466), Mn (733-741), Cr (297-342), Fe (1327-1574) for teff. Cd and Pb were not detected in the teff and soil samples. The soil and teff samples collected from the two cement factories contained significant level of heavy metals. Except iron, the level of heavy metals in soil and teff samples were above the permissible limit of FAO/WHO.