Comparative study of toxic heavy metal residues and other properties of honey from different environmental production systems.

Honeybees forage a large spatial area around the hives. In addition, honey production takes place in various environments, and polluted environment is often hard to detect. It impacts both human and beehive health, especially through honey which is used for human consumption. Pollen analysis was conducted by a novel approach through a multivariate principal component analysis where it was possible to obtain grouping patterns related to foraging plant species. Samples of honey were acquired from three different environmental production systems: (i) honey from the apiaries in the vicinity of thermal power plant, (ii) apiary of certified organic production and (iii) the conventional production with semi-controlled production. Significantly higher contents of the Pb, Cd and Zn are found in the analysed honeys taken near the thermal power plant compared with those of the other analysed honeys. The origin of Zn, Pb and Cd in the honey is the contaminated forage plants and foraging honeybees. Honey from certified organic production differentiated significantly from other two types of production by the water content, electrical conductivity and total soluble solids and notably it contained significantly less ash and lead. There is a clear advantage of certified organic honey in terms of heavy metal residues as the most prominent pollution factor in honey. Therefore, honey can be used as the broad range environmental pollution indicator, as bees will forage on polluted plants and bring the pollutant from a wide spatial range inside the hive, where it can be traced in the honey. Graphical abstract.