Assessment of environmental impact on essential and toxic elements composition in natural honeys by using inductively coupled plasma mass spectrometry.

Abstract

The quality of natural honey depends upon many factors with significant contribution of environmental factors. In this study, environmental impact on the quality of honey was assessed by determining concentrations of 11 essential and 17 toxic elements in 24 different honey samples of northern and southern regions of Pakistan and Turkey using inductively coupled plasma mass spectrometry. Statistical analysis showed higher variance in the concentrations of Cu, P, and Mo (essential), and Ga, Rb, Cs, Ba, and Pb (toxic) among all the honey samples (coefficient of variance > 100). Multivariate comparison based on botanical flora, honey bee species, and geographic regions revealed that the honeys of different botanical flora exhibited statistically nonsignificant difference in elemental composition, whereas, species wise, honeys of Apis dorsata contained significantly higher concentration of P than honeys of Apis mellifera and Apis flora (p < 0.01). Geographical regions wise, the honeys showed statistically significant difference in concentrations of six essential elements (K (p < 0.01), Mn (p < 0.001), Fe (p < 0.001), Cu (p < 0.05), P (p < 0.001), and Mo (p < 0.01)), and two toxic elements (V (p < 0.01) and As (p < 0.05)). Principal component analysis (PCA) using the essential elements contents clustered uni-floral honeys together separating out 3 multi-floral honeys including the artificial one, whereas PCA using concentrations of toxic elements showed mixed clustering of all honey samples, representing their independence of floral type. Taken together, our analyses show that the environmental factors of the geographical regions, apart from the honeybee species and the botanical flora, have profound impact on the elemental composition in the natural honeys affecting their quality. Although the concentrations of the toxic elements in the honey samples were not exceeding the permissible limit of FAO/WHO, yet we suggest regular surveillance on toxic elements in the honeys to avoid their harmful effects on human health.