Arsenic is a toxic metal occurring naturally in the environment. Arsenic can also be released into the environment as a result of, for example, mining and the use of fossil fuels.
In nature, arsenic occurs in various forms: inorganic salts and organoarsenic compounds. The most toxic form of arsenic is inorganic arsenic. Some organoarsenic compounds, such as arsenobetaine, the most common form of arsenic in fish, are harmless in the quantities contained in food.
Cereal products, especially rice, are the major sources of inorganic arsenic in food. The percentage of inorganic arsenic of the total arsenic accumulated in these plants (all forms of arsenic combined) varies somewhat depending on the growing area and variety.
Adverse health effects
The arsenic familiar from crime novels is an inorganic arsenic salt, but the levels of arsenic in foods are insufficient to cause the consumer symptoms of sudden arsenic poisoning, such as nausea, diarrhoea or death.
Prolonged high exposure to arsenic has been associated with peripheral circulatory disorders, limb nervous system disorders and cardiovascular disease. The International Agency for Research on Cancer (IARC) has classified arsenic as carcinogenic to humans, but the effect has a threshold below which the risk of cancer does not yet rise. Arsenic causes cancers, especially in the lungs, skin and bladder, possibly also the kidneys, liver and prostate. Most arsenic is eliminated from the body within a few days.
The European Food Safety Authority (EFSA) has set the toxicological reference value (BMDL01, Benchmark dose) for inorganic arsenic at 0.3–8 µg/kg bw/day. The Joint Expert Committee on Food Additives (JECFA) of WHO and the FAO has set the BMDL05 value for inorganic arsenic at 3.0 µg/kg bw/d. The values correspond to concentrations at which the long-term risk of various cancers, in particular lung cancer, increases in the population by 1% (EFSA value) or 0.5% (JECFA value) compared to the population not exposed to arsenic.
Maximum levels in food
EU legislation ((EU) 2023/915 as amended) sets maximum levels for inorganic arsenic in rice and certain rice products.