Level of selected heavy metals in surface dust collected from electronic and electrical material maintenance shops in selected Western Oromia towns, Ethiopia

Surface dusts from electronic and electrical material maintenance workshops may present significant environmental contamination. The aim of this study was to determine levels of selected heavy metals (Cu, Ni, Co, Cd, Cr, Pb, Zn, and Fe) in surface dust samples collected from electronic and electrical device maintenance workshops located in Ambo, Gedo, and Nekemte towns in Ethiopia. An optimized wet digestion procedure (acid mixture, 3mL HNO3, 2mL HClO4, and H2O2; digestion time, 2h; digestion temperature, 200 degrees C) was employed prior to the metals determination by flame atomic absorption spectroscopy. The average amounts of the metals were found to be in the ranges of 73,970-58,980, 59,290-51,120, 8570-5778, 1273-1126, 708.9-261.6, 111.7-101.0, 114.9-89.50, and 12.30-9.620mg/kg for Pb, Fe, Cu, Cr, Zn, Co, Ni, and Cd, respectively. The results showed that the investigated surface dust samples contained significant levels of the analyzed heavy metals compared to soil samples collected from the corresponding control sites. The heavy metal concentrations in the investigated samples from the three towns followed a decreasing order Pb > Fe >> Cu >> Cr > Zn > Co > Ni > Cd, indicating the presence of elevated amount of Pb in the surface dust samples. The significantly high levels of heavy metals detected in all surface dust samples from electronic and electrical device maintenance shops could be inferred to the seepage of these metals from electronic materials during the maintenance procedures. Based on the result obtained, we strongly recommend a strict monitoring and disposal (policy issue) of wastes generated from electronic and electrical device maintenance shops.