Contamination of foods with arsenic and mercury in Iran: a comprehensive review

Human and animals are exposed to heavy metals such as arsenic (As) and mercury (Hg) through atmospheric depositions, industrial effluents, chemical pesticides and fertilizers, erosion of geological beds, and mining wastes which can result in the contamination of food chains. The aim of the current study was to review the available papers reporting contamination levels of As and Hg in commonly consumed foods in Iran. A descriptive search was carried out with specific keywords and entry criteria in databases of Science-Direct, PubMed, Scopus, Google Scholar, and Scientific Iranian Database (SID) published from January 2000 to July 2018. All articles were assessed by two reviewers, and final decision was made through discussions or a third reviewer arbitration. The articles were categorized based on the type of food groups including rice, fruit, vegetable, fish, seafood, drinking water, tea, and miscellanies. Of 221 identified articles on As and Hg contaminations in foods, 92 articles were selected using defined criteria. Published articles were reviewed to report contamination (mean and rate) of each food group in Iran. Results showed that rice and fish included the highest contamination rates of As and Hg, respectively. In general, As and Hg contents in Iranian foods cause serious health concerns due to the consumption quantities of the main foods. Further risk-based surveillance studies must be carried out to decrease exposure to As and Hg from dietary and non-dietary sources.