Contamination of chicken eggs supplied in Tehran by heavy metals and calculation of their daily intake

Chicken eggs, owing to richness in protein and essential minerals, are used in many communities and for all age groups. Metals are considered as one of the most important environmental pollutants which may lead to egg contamination. The consumption of contaminated eggs can harm human health. The aim of this study was to evaluate heavy metal (arsenic, cadmium, lead, nickel, copper, zinc and iron) contents in chicken eggs supplied in Tehran. Daily intake rates of heavy metals were also calculated. A total of 29 chicken eggs were sampled from various food stores in Tehran.Sample preparation was performed using wet acid digestion. Heavy metals concentrations were determined using ICP-OES. Data analysis was carried out by means of the statistical software SPSS as well as Excel (V.2.26). Kruskal Wallis and ANOVA tests were executed to compare heavy metal concentrations between different brands. Mean concentrations of cadmium, lead, arsenic, nickel, copper, iron and zinc in collected chicken eggs were 0.01, 0.074, 0.03, 0.014, 1.46, 34.37 and 12.55 mg/kg, respectively. Iron and cadmium respectively showed the highest and lowest daily intake through chicken egg consumption. It was concluded that the levels of heavy metals in sampled chicken eggs were less than permissible limits and thus are considered safe. However, due to the importance of food contamination in public health, the continuous monitoring of these contaminants in food is recommended.