Heavy metals, definition, sources of food contamination, incidence, impacts and remediation: A literature review with recent updates

Document Type : Review Articles


Food Toxins and Contaminants Dept., National Research Center, Dokki, Cairo, Egypt


Heavy metals are any metallic element that has a proportionally high density and is poisonous at low concentrations. Also, heavy metals are non-biodegradable in natural environments and categorized in two groups as toxic metals (i.e. Pb, Cd and As etc.) and essential metals (i.e. Cu, Zn, Mn, Fe, Ni and Cr etc.). The releasing sources of heavy metals are divided to the natural and anthropogenic sources. Increase of urbanization and industrialization lead to increase the metal contamination of food. The toxic metals can be translocated to different food through different sources such as irrigation water, agricultural soils, agricultural practices, air pollution, animal feed and packaging materials. The toxic metals are non-biodegradable, non-thermo degradable and extremely persistent in the environment; thus readily accumulate to the different food. The metal contamination of different food such as agricultural crops, meat, fish, milk and egg threatens both food safety and security. Contamination of agricultural soils, irrigation water, plants and animals with toxic metals cause their incorporation into the food chain and cause a great threat to human health. Most metals have toxic effects on human health and accumulate in the different organs such as skeleton, liver, spleen, and kidney. Metals have negative effects on plant and animal production. So, application of different remediation techniques became necessity to reduce the toxic heavy metals pathway to the food chain and human body. Metal nanoparticles used in benefits application, but may be have some risks.


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