lead and cadmium concentrations in raw milk and dairy products in zanjan, iran: a study on winter and summer variations

Background: the contamination of food with heavy metals is a significant concern for humans. among food products, milk and dairy products have received more attention due to their widespread consumption at all ages, particularly among children. the aim of this study is to determine the concentration of lead and cadmium in milk and dairy products in zanjan.methods: 132 samples of milk, doogh, yogurt, and cream were collected from zanjan city during the winter and summer of 2020-2021. the lead and cadmium levels in the samples were quantified using microwave digestion and graffiti furnace atomic absorption spectrophotometry.results: the average concentrations of lead and cadmium in traditional milk, industrial milk, doogh, full-fat yogurt, low-fat yogurt, and cream samples were 96.23, 89.91, 78.79, 49.79, 53.74, 106.08, and 2.76, 2.07, 2.59, 1.09, 1.34, 5.60 µg/kg, respectively. the mean lead concentrations in milk and dairy products during winter were significantly higher than those during summer, whereas the mean cadmium concentrations during summer were higher than those during winter for all dairy products.conclusion: the lead and cadmium concentrations in most of the samples exceeded the who-fao standards of 20 and 2.6 µg/kg for lead and cadmium, respectively. therefore, prompt action is necessary to address this issue.