Study of the Effects of Selected Heavy Metals in Wrapping Sheets and Food Products

Abstract

Paper is light, cheap, easy to use and discard or recycle, and quite environmentally friendly which makes it a popular food packaging  material in Nigeria especially used paper. In this study, 5 different food packaging papers (foil, ink pen, printed, plain and newspapers)  were used to wrap bean cake at varying temperatures (room temperature, 45 ^oC, 65 ^oC and 85 ^oC) for 30 minutes using Atomic  Absorption Spectroscopy. The packaging papers were analyzed for levels of toxicity of 10 heavy metals (Pb, Ni, Cr, Mn, Cu, Zn, Co, As, Hg  and Fe).The quantities of the selected heavy metals in the papers were compared with permitted values published by the European  Council for food contact materials where Pb, Ni, As, Co and Cr were observed to be more than the permitted concentration in the  samples, while Fe, Cu, Zn and Mn were observed within the permitted concentration. The food samples have concentration range of; Ni  (BDL – 0.03 ppm), Pb (BDL – 0.03 ppm), Co (BDL), Ar (BDL) and Cr (BDL – 0.05 ppm) with maximum legal concentrations of 0.02 ppm, 0.01  ppm, 0.01 ppm, 0.1 - 0.2 ppm and 0.05 ppm respectively. Comparison of the determined concentrations of heavy metals in the food  packaging papers with permitted standards for food contact materials suggests that the presence of these contaminants may be  associated with health hazards but the migration of these heavy metals to the food sample were observed to be in low concentrations  and below the permissible level of the WHO/FAO standard for food, except for a few concentrations of lead and nickel which were above  the permissible limit. Even at low concentration, heavy metals are toxic to biological cells as they do not undergo biodegradation. Consequently, they accumulate in humans, leading to various diseases and disorders, even when present in low concentrations. But  based on the migration ability of these heavy metals from the food packaging paper to the food product, the best packaging paper is foil  paper with very low concentration of metals migrating compared to other papers.