What is the significance of heavy metals in food?
How do heavy metals get into food?
Heavy metals are ubiquitous in the environment. They enter food through industrial processes, exhaust gases, sewage sludge or pesticides — via plants or the meat of grazing animals — into food. These include, among others, lead, cadmium, mercury and arsenic.
Furthermore, certain minerals and trace elements are also classified as heavy metals and are essential for humans, animals and plants. These include, for example, zinc, iron, manganese and copper.
Heavy metals can accumulate in plants and in the organs of farm animals; accordingly, foods produced from them can be contaminated with high levels of heavy metals. Examples include cadmium in oilseeds, mushrooms or cocoa, and arsenic and mercury in fish and shellfish.
What legal regulations are there?
Regulation (EU) 2023/915 on maximum levels for certain contaminants in food (Contaminants Maximum Levels Regulation) sets maximum levels for the heavy metals lead, cadmium, mercury, inorganic arsenic and tin. From 1 July 2025, maximum levels for nickel, among others in nuts, vegetables, legumes, certain oilseeds and chocolate, will be added.
Analysis:
Heavy metals are detected analytically using ICP-MS (Inductively Coupled Plasma Mass Spectrometry). This is the most commonly used method in trace element analysis.
Available heavy metals / minerals are aluminium, antimony, arsenic, barium, bismuth, lead, boron, cadmium, calcium, chromium, cobalt, iron, potassium, copper, magnesium, manganese, molybdenum, sodium, nickel, mercury, sulfur, selenium, strontium, phosphorus, thallium, titanium, vanadium, tin, zinc.
Regulation (EC) No 396/2005 on maximum residue levels of pesticides in or on food and feed of plant and animal origin (Pesticide Regulation) lays down further maximum levels for copper and mercury.
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Sources:
- BVL (Bundesamt für Verbraucherschutz und Lebensmittelsicherheit) on heavy metals; available at: www.bvl.bund.de
- LGL Bayern (Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit) on heavy metals; available at: www.lgl.bayern.de, www.lgl.bayern.de