Elemental Composition of Honeys from Greece-Possible Use as Environmental Indicators

Abstract

The evaluation of trace element concentration patterns of honey samples was tested either to indicate the authenticity of the sampling location, or to indicate environmental contaminations. Greece was selected because of its heterogenous structure, having plains (<100 m above sea level), hills (100-500 m) and mountains, as well as big industrial cities (Athens, Patras), small towns and rural areas at rather close distances to one another, as well as occasionally proximity to the seaside. Contrary to plant leaves, honey samples might be indicative for an area of 7 km². 4 grams of honey were gently digested with nitric acid in open Erlenmeyer flasks on a hot plate, made up to 25 ml with water, and submitted to multi-element determinations by ICP-OES (inductively coupled plasma optical emission spectroscopy), reading 25 elements, of which 16 could be finally used; others were below detection limits. In addition, Cd-Cr-Mo-Pb were determined by graphite furnace AAS (atomic absorption spectrometry). The botanical origin largely dominated the trace element concentration patterns based on sample weights. Honeydew honeys were higher in ash and most element contents, except boron. Because honeydew honeys were largely found in the mountains and rural areas, this counteracted effects of enviromental pollution. Ash-based concentratin data, however, might reflect dust immission within the area of the bees´ activity. Within ash-based concentration data, some environmental trends could be noticed. Na-B-Cr-Mo-V-Zn decreased with the distance to the sea, B-Li-Na-V increased with increasing population, and Cr-Li-Ni increased with increasing height above sea level, the latter reflecting abrasion of the Greek basic rocks. With respect to their mean occurrence in the earth crust, K-P-S, and particularly B get enriched in ash-based concentration data of honey samples. Possible environmental contaminations were defined as outliers within the ash-based sample dataset.