Occurrence in food
Cadmium is a toxic heavy metal commonly occurring in the environment. Its most important natural sources are volcanoes and weathered heavy metal-bearing rock. Cadmium is also released into the environment as a result of human activities, such as the manufacture and use of phosphate fertilisers, the battery industry and waste management. Finland currently has a derogation from the European Commission to ban the placing on the Finnish market of mineral fertilisers containing more than 50 mg of cadmium/kg of phosphorus. The cadmium content of ash fertilisers is also regulated.
Cadmium ends up in food either by being absorbed from the soil into the plant as it grows or through air deposition. In animals, as in humans, dietary cadmium accumulates in the internal organs, especially the kidneys and liver. Cadmium is generally higher in game than in domestic animals and, due to the high levels of heavy metals, the liver and kidney of equine animals, the kidney of bovine animals over the age of four years, liver and kidney of other ungulates kept as livestock, farmed game and reindeer (where there are reasonable grounds to suspect that they have accumulated levels of heavy metals or other contaminants in excess of the maximum levels), the liver and kidney of elk over the age of 1 year of age, kidney of wild hares and rabbits, organs and subcutaneous and abdominal fat of seals are not permitted for use in food.
Cadmium can also migrate to foods from food contact materials, such as decorated ceramics or tin-coated containers.
Adverse health effects
Cadmium is eliminated slowly from the body: its biological half-life is measured in years or even decades. Prolonged exposure to low levels of cadmium has been associated with impaired renal tubular function and the consequent increased risk of osteoporosis. The European Food Safety Authority has set a maximum tolerable weekly intake (TWI) for cadmium of 2.5 µg/kg bw/week. The consumer can therefore consume a dose of this size every week of their lives without suffering any health problems such as impaired kidney function.
The International Agency for Research on Cancer (IARC) has classified cadmium as a human carcinogen, but a link to the occurrence of lung cancer and some other cancers has been observed in occupational or environmental exposures, i.e. at higher doses than those typically obtained from food
Maximum levels in food
EU legislation ((EU) 2023/915 as amended) sets maximum levels for cadmium in vegetables, fruit, mushrooms, cereals, cocoa and chocolate products, meat and offal, muscle meat of fish, crustaceans, bivalve molluscs, cephalopods, in infant formulae and follow-on formulae, processed cereal-based foods and baby foods for infants and young children and food supplements.
The EU Ceramics Directive, which has been implemented in Finland by Decree 165/2006 of the Ministry of Trade and Industry (KTM), sets a limit value for cadmium migrating from ceramics to food of 0.07 mg/dm2, 0.1 mg/dm2 or 0.3 mg/dm2 depending on the size and purpose of the container. In addition, Finland has a national decision 268/1992 (KTM), which sets a specific migration limit value of 0.1 mg/dm2 for all food contact materials. Migration from food contact materials intended for young children should only be 1/10 of this amount. The same regulation also sets limit values for lead, chromium and nickel migrating from food contact materials.