Changes in the concentrations of selected toxic and essential elements in ewe milk from area with a potentially undisturbed environment

Abstract

The aim of this study was to evaluate the effect of lactation on the concentration of selected essential and toxic elements in sheep milk from an area of Slovakia with a potentially undisturbed environment and to find out the actual contamination of the selected area, in the aspect of its environmental character. The research was conducted with 400 sheep (Tsigai breed), and the milk samples were taken during the lactation periods (early, middle and late lactation stage). Sheep were reared on the extensive pastures, reared indoors afterward, fed with pasture ad libitum. Milk samples were collected after morning and afternoon milking. The samples of milk were analysed toxic and essential elements (Ca, Se, Mg, Zn, Fe, Cu, As, Cd, Hg, Ni, Pb) by the method of atomic absorption spectroscopy (AAS). The macro elements concentration in milk changes following the stages of lactation (p<0.05). There was found that Ca milk concentration increased gradually in the following stages of lactation while Mg, Se, and Fe only in the last stage of lactation. The Zn concentration in milk was the highest during summer (p<0.05). Simultaneously the contents of essential elements (Cu) and toxic elements (As, Cd, Hg, Ni, Pb) in milk were very low, below the limit of quantification. In conclusion, ewe's milk from potentially analysed areas of Slovakia is safe and poses no risk to consumer health, and is suitable for use directly or in dairy processing.