Monitoring of Elemental Composition of Honey from Selected Regions of Ghana Using Instrumental Neutron Activation Analysis and Atomic Absorption Spectroscopy

ABSTRACT Honey is a sweet, thick and viscid fluid collected from beehives and usually found in cells of the honey comb. It is produced from nectar collected from various flowers by honeybees and processed. Among the important uses, pure and undiluted honey serves as natural sweetener and contains a broad variety of vitamins for human consumption. Due to its global demand, monitoring of the quality of honey is of great significance. In this study, honey samples were collected systematically from farmers and retailers in the Brong Ahafo, Ashanti and Greater Accra regions of Ghana. The sampling was done along the farmer-to-trader channels, to assess the quality of honey produced from various regions and to trace the sources of elemental contamination. Physicochemical studies; pH, electrical conductivity and specific gravity were done. The levels of selected toxic heavy metals (Hg, Pb, Cd, V, Cr, As) and essential metals (K, Na, Ca, Mg, Mn, Cu, Fe, Co) in the honey samples were analysed using instrumental neutron activation analysis (INAA). Flame atomic absorption spectrophotometry (FAAS) was also employed to determine elements such as Pb, Co, Cr and Fe. All the honey samples were found to be acidic, with pH ranging from 3.60 to 6.10. The acidity of honey is significant as it inhibits the growth of microorganisms. The values agrees favourably with the permitted pH limits of 3.40 to 3.60 for good quality honey, set by the National Honey Board of United States. The electrical conductivities measured ranged from 11.9 µS/cm to 44.4 µS/cm. The values were within the acceptable limits set by Ghana Standards Authority and other organizations ( Ca > Na > Mn > Al > Mg > Cu > V > Fe > Pb > Co > Cr, in the selected sampling sites evaluated in the three regions. The values ranged from 0.009 – 0.094 mg/kg for Co; 0.010 – 0.423 mg/kg for Pb; 0.010 – 0.423 mg/kg for Cr; 1.548 – 11.052 mg/kg for Fe; 0.490 – 35.021 mg/kg for V; 4.524 – 288.298 mg/kg for Cu; 75.697 - 681.236 mg/kg for Mg; 60.159 – 1186.369 mg/kg for Al; 145.668 – 3501.004 mg/kg for Mn; 900.214 – 8277.351 mg/kg for Na; 2.393 – 283.690 g/kg for Ca and 112.933 – 1770.770 g/kg for K. With the exception of Cu, the concentrations of the metals were below the permitted limits sets by Ghana Standards Authority, Codex Alimentarius and the Polish Standards. The metal contents of the honey in the various regions considered were similar. There were significant differences in concentrations in most of the samples as monitored from one sampling site to the other. Significant differences in concentrations was also observed as the honey goes through treatment processes. This affirms that the various processes honey goes through prior to reaching the consumer significantly affects its composition.