Arsenic is a semimetal that is known primarily for its toxicity. Arsenic can enter plant foods via environmental influences. Comparatively high levels are found in rice and subsequently in products made from rice (rice milk, rice wafers, etc.).

In nature, arsenic occurs as a component of many minerals and enters the atmosphere through volcanic eruptions, for example. However, arsenic is also released by mining, metal industry and combustion of fossil fuels (coal, petroleum). In the past, arsenic was also used in the production of pesticides, fertilizers and wood preservatives. This use is now banned.

Arsenic occurs in different forms (inorganic and organic), which are toxic in different ways. The more toxic form, inorganic arsenic, is predominantly found in soil, while organic arsenic compounds are predominantly found in water. Arsenic is also present in cigarette smoke.

Arsenic in food

Since arsenic is a natural component of the earth's crust, it is found in the soil, water and air. Arsenic also enters the environment through exhaust fumes, wastewater, and human use, and leaching from arsenic-containing ores can cause it to enter groundwater.

Arsenic can get into plant foods due to arsenic content in the soil, atmosphere, or water used for irrigation. Rice may contain more arsenic in inorganic form than other plant foods. The arsenic content in rice varies depending on the arsenic content of the soil and water in the growing region, and also depends on the method of cultivation and the variety of rice. For example, if the fields are flooded during cultivation, this leads to a higher availability of arsenic in the soil. If the irrigation water also has high arsenic levels, the amount of arsenic in the rice grains increases.

Algae, fish and seafood take up arsenic through the water, with mainly organic arsenic compounds being accumulated.

Inorganic arsenic is toxic and carcinogenic. The ingested arsenic reaches all organs of the body. If inorganic arsenic is ingested over a long period of time, it can contribute to the development of diseases: These include skin damage, heart disease, respiratory diseases and various types of cancer such as skin, bladder and lung cancer. During pregnancy, arsenic can be transferred from the mother to the growing child and have negative health effects on the child.

Inorganic arsenic is regulated by law in Regulation (EU) 2023/915. On 3 March 2023, in addition to the maximum levels already set for rice and rice products, maximum levels were also set for other product groups in the supplementary Regulation (EU) 2023/465.

During a priority action on table salt in 2021, in which 74 samples were analysed for arsenic, among other things, two samples showed arsenic levels at the limit of objectionability. However, the risk assessment of these samples for arsenic showed that a non-relevant risk to human health can still be assumed.

As part of official controls, the regulated product groups are checked for compliance with the statutory maximum arsenic levels. In 2019, there was a focus campaign on buffer products in which 17 samples of rice cakes were analysed for inorganic arsenic. There were no complaints in any of the samples, all of which were below the maximum level. In the years 2015 to 2018, a total of 81 rice and rice products were analysed for inorganic arsenic. Of these, 21 were basmati rice, 1 purple rice, 1 black rice, 5 jasmine rice, 4 cooked bag rice, 10 long grain rice, 2 milk rice, 6 parboiled rice, 1 rice biscuit, 2 rice noodles, 8 rice cakes, 2 wholemeal rice cakes, 5 risotto rice, 10 wholemeal rice and 3 wild rice. The analyses revealed average levels of inorganic arsenic of 0.089 mg/kg of food. Only one sample of wholegrain rice, with a concentration of 0.301 mg/kg, exceeded the maximum permitted inorganic arsenic content of 0.25 mg/kg for wholegrain rice.

Our analyses in the period 2007-2014 revealed high average levels of inorganic arsenic in algae (1,901 µg/kg) and rice (101 µg/kg). Although a high average content of total arsenic was measured in the "fish and seafood" group, the content of inorganic arsenic is low (31 µg/kg).

In other international studies, significantly higher levels of inorganic arsenic were detected in rice products such as rice cakes, rice porridge and rice drinks compared to rice, although the cause still needs to be clarified(BfR, 2015).

The arsenic content in rice can also be reduced by washing with water before cooking or steaming (EFSA, 2015). Excess water should be poured off after the cooking process.

In principle, the diet should be varied. This also applies to cereal products. Since rice in particular has higher arsenic levels, other cereals such as wheat (bulgur, cous cous), rye, oats, spelt, green spelt, rolled barley or gluten-free alternatives such as millet, corn and the pseudocereals buckwheat, quinoa, amaranth or potatoes should be eaten for variety.

Rice products such as rice wafers, rice porridge and rice drinks should only be consumed occasionally and not daily in the interests of preventive health protection. Nevertheless, rice should remain part of a varied diet.

Inorganic arsenic has been classified as Group 1 "carcinogenic to humans" by the International Agency for Research on Cancer(IARC), as a link between a high intake of inorganic arsenic and skin, lung and bladder cancer has been demonstrated.

EFSA risk assessment 2024

In its 2024 assessment, the European Food Safety Authority (EFSA) came to the conclusion that inorganic arsenic can lead to the following adverse health effects

Skin, bladder and lung cancer, spontaneous abortion, stillbirth, infant mortality, congenital heart disease, effects on neurological development, ischaemic heart disease, respiratory disease, chronic kidney disease, arteriosclerosis, reduced birth weight and skin lesions.

In its risk assessment, EFSA established a BMDL05 of 0.06 µg/kg body weight per day based on a case-control study on skin cancer. This is a conservative estimate of the lowest possible dose and is associated with an increased incidence of skin cancer following exposure to inorganic arsenic.

As inorganic arsenic is mutagenic and carcinogenic, the risk characterisation was based on the MOE approach using the data from the exposure assessment by EFSA in 2021. The MOE for adults was between 2.0 and 0.4 for average consumption and between 0.9 and 0.2 for high consumption (P95).

Even taking into account the uncertainties of the risk assessment, EFSA concluded that there are health concerns from inorganic arsenic in food based on the exposure assessment. These findings confirm the outcome of EFSA's previous assessment of inorganic arsenic in food in 2009.

EFSA risk assessment 2009

The European Food Safety Authority(EFSA) established various benchmark doses(BMDL01 values) in the range of 0.3 - 8 µg/kg body weight(bw)/day for risk characterisation and calculation of the MOE (Margin of Exposure). The MOE value is the ratio between the dose at which a small but measurable negative effect can be detected (reference point - BMDL) and the total intake for consumers.

AGES risk assessment 2015

We analysed a total of 1,080 samples for total arsenic in the period January 2007 - June 2014. However, it is important to differentiate between the individual types of arsenic, as the different types have different levels of toxicity (inorganic arsenic is more toxic than organic arsenic). For this reason, the levels of total arsenic were converted into levels of inorganic arsenic using the EFSA (2009) conversion factors. Rice (average content of inorganic arsenic 101 µg/kg) and algae (1,901 µg/kg) were particularly heavily contaminated with inorganic arsenic. Although a high average content of total arsenic was measured in the "fish and seafood" group, the content of inorganic arsenic is low (31 µg/kg). The intake of inorganic arsenic via different foods was calculated using average levels of inorganic arsenic in foods and average intakes of children, women and men. Rice was identified as the most significant source of inorganic arsenic intake for the Austrian population (31 % - 36 %), followed by the product groups "bread and rolls" and "fruit and fruit products" (10 % - 15 %).

Based on the data currently available, the following exposure estimate was obtained for the Austrian population: on average, children ingest 0.15 µg, women 0.16 µg and men 0.13 µg of inorganic arsenic per kg of body weight per day. Frequent consumers of rice and "bread and rolls" or rice and "fruit and fruit products" consume an average of 0.29 µg (children), 0.44 µg (women) and 0.39 µg (men) of inorganic arsenic per kg of body weight per day.

The calculated exposure to inorganic arsenic is therefore in the range of the BMDL01 values of 0.3 -8 µg/kg bw/day. There is therefore no or only a low MOE. In its 2009 exposure assessment, the EFSA also found that there is no or only a low MOE for inorganic arsenic and concluded that "a risk to some consumers from the intake of inorganic arsenic via all foods cannot be excluded".