Exposure assessment of trace elements in fresh eggs from free-range and home-grown hens analysed by inductively coupled plasma optical emission spectrometry (ICP-OES)

A total of 21 metals (Na, K, Ca, Mg, V, Mn, Fe, Cu, Zn, Cr, Mo, Co, B, Ba, Li, Sr, Ni, Si, Al, Pb, Cd) have been analysed, using inductively coupled plasma atomic emission spectroscopy (ICP-OES), in a total of 288 eggs from free-range and home-grown hens in order to establish differences in metallic content according to the breeding system. Method accuracy was checked by the analysis of certified reference materials (SRM 1515 Apple Leaves, SRM 1548a Typical Diet and SRM 1567a Wheat Flour from NIST) and the recovery percentages were between 97.7-103%. The results obtained were in good agreement with 95% confidence limit with the certified concentrations, relative standard deviation (RSD) values were lower than 25%. Significant differences (p < 0.05) in the metal content between the two breeding systems have been demonstrated. The daily consumption of eggs from free-range hens (24.3 g/person/day for children, 31.2 g/person/day for adults) contributes to the intake of metals, such as Na (2.7% adults, 2.1% children), Fe (7.4% males, 3.7% females, 4.3% children), Zn (4.4% males, 5.9% females, 4.1% children) and Cu (9.6% adults, 8.3% children). Macroelements and trace elements contribution is lower in home-grown eggs and with higher amounts of toxic metals.