Heavy metal contents of selected commercially available oil-based house paints intended for residential use in Ethiopia.

Abstract

Environmental pollution by paint-based heavy metals have been continued to be a great concern. Thus, this study was aimed at investigating the levels of selected heavy metals (Ni, Cd, Cr, Zn, and Pb) in oil-based paint samples being manufactured and sold in Ethiopia. An optimized acid digestion procedure using conc. HNO3, conc. HClO4, and 30% H2O2 mixture by volume ratio of 3:4:1mL, respectively, for 2h at 200°C were used for paint samples digestion, and the contents of heavy metals were assayed by flame atomic absorption spectroscopy. The 13 out of 14 (92.9%) analyzed paint samples had contained Pb > 90mg/kg with the highest content of 51,200mg/kg (dry weight) in the orange colored paint. Likewise, the levels of Cr, Ni, and Zn obtained were ranged from 43.75 to 50.00, 60.02 to 128.81, and 323.69 to 1102.16mg/kg (dry weight), respectively, while Cd was not detected in all the paint samples. Generally, the mean contents of heavy metals in the investigated paint samples have followed the order: Pb > > Cr > Zn > Ni, demonstrating the occurrence of higher lead metal content. The elevated levels of heavy metals detected in the oil-based paint samples could be attributed to the continued usage of these metals in different form during paint manufacture. On the bases of the findings, a strict monitoring and evaluation of paints being produced in Ethiopia has been recommended so that the manufacturers comply with the national (policy issue) and/or international regulations on the levels of toxic metals in paints to ensure consumers safety.