Levels of toxic and essential metals in varietal honeys from Podkarpacie

The mineral composition of honey largely depends on its botanical origin as well as on the climatic conditions and the geographical area where it was produced. The aim of the study was to determine the content of toxic (Cd, Pb, Hg, Al and Tl) and essential (Ca, Mg, Zn, Fe, Mn, K, Cu) elements in honey samples obtained in Podkarpacie, a region in the south-east of Poland. Varietal honeys (n = 106) including nectar (multifloral, dandelion, oilseed rape, goldenrod, linden, buckwheat) and honeydew honeys were collected directly from beekeepers. The mineral composition of honey was determined by the ICP-OES method preceded by wet mineralization. Mercury was undetected while the concentration of other heavy metals in all the studied honey samples (0.01-0.03 mg kg-1 for Cd and 0.02-0.09 mg kg-1 for Pb) were below the maximum allowable contaminant limits. The level of aluminium in honeydew honey was higher than in other varietal honeys (from 10-fold more than in dandelion to 95-fold more than in oilseed rape honey). The honeys were confirmed to be rich in potassium (310.6-2548.4 mg kg-1), calcium (34.7-108.6 mg kg-1) and magnesium (23.7-63.3 mg kg-1). The content of the other microelements was determined in the following order: Mn>Fe≥Zn>>Ni≥Cu. The highest levels of microelements were found in the buckwheat honeys (Mn – 7.82; Fe – 0.21; Zn – 2.90; Cu – 0.86; Ni – 0.20 mg kg-1). Significant differences (p < 0.05) in the mineral content between the honey types were found, and dark honeys (honeydew and buckwheat honeys) contained more essential elements than light honeys.