Analysis of organic and inorganic arsenic in food using IC-ICP-MS

Background and toxicity

Arsenic (As) is a widespread element that occurs in soil, groundwater, plants, seawater and animals due to natural occurrence but also anthropogenic environmental contaminations. Arsenic can be present in organic and inorganic forms.

Over the past few years, the European Food Safety Authority (EFSA) has published a series of scientific toxicological assessments on various organic and inorganic arsenic compounds:

Inorganic arsenic species (iAs)

Inorganic arsenic species (iAs) are classified as carcinogenic. In food and feed, iAs are predominantly bound in the oxidation state +3 (As^III) or +5 (As^V) in thiocomplexes or are present as oxoanions arsenite (As^III) and arsenate (As^V).

Already in 2009, the EFSA described an increased risk of skin, lung and bladder cancer as well as skin lesions caused by inorganic arsenic^[2]. In its new Scientific Opinion published early in 2024, a lower reference point (RP) of 0.06 µg iAs/kg body weight/day is specified, which already has a small but measurable adverse effect. In addition to the types of cancer already described in 2009, chronic kidney disease, respiratory disease, spontaneous abortion, stillbirths, infant mortality and neurodevelopmental effects are now also attributed to iAs^[3].

In its Scientific Report from 2021, the EFSA describes cereals (especially rice), cereal products, and drinking water as the main sources of inorganic arsenic intake. For infants, toddlers, and children, EFSA’s exposure assessment identifies cereal-based foods for infants and young children as well as biscuits, rusks, and cookies for children as particularly significant sources^[4].

Small organoarsenic compounds

In July 2024, EFSA extended its assessment of arsenic compounds with an opinion on small organoarsenic compounds^[5]. Main subject of this opinion are monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). The assessment was carried out using the Margin of Exposure (MOE) approach. Based on the available data, no health concerns could be derived for MMA, regardless of the age and consumer group. However, DMA increases the occurrence of urinary bladder tumors in animal experiments and was also identified as potentially genotoxic.

MMA and DMA are likewise ingested via fish and fish products, but also rice plays a role as a source of exposure for DMA.

Complex organoarsenic species

Another EFSA Opinion published in December 2024 assessed the so-called complex organoarsenic species such as arsenobetaine, arsenosugars, and arsenolipids. These are mainly found in fish and seafood. No health risk to humans could be identified for arsenobetaine and glycerol arsenosugars. Other arsenosugars and arsenolipids could not be assessed due to insufficient data^[6].

Regulatory provisions

Regulation (EU) 2023/915^[7] sets maximum levels for inorganic arsenic as the sum of As^III and As^V in rice, rice-based products and fruit juices as well as in food for infants and young children. Furthermore, a maximum level of total arsenic in salt is laid down. The newly published Amending Regulation (EU) 2025/1891^[1] expands the maximum levels for inorganic arsenic to fish and seafood.

With its Monitoring Recommendation (EU) 2015/1381^[8], the European Commission continues to request its member states to monitor the levels of total arsenic and inorganic arsenic in a wide range of foods.

Maximum levels for total arsenic in certain feed products are set by Directive 2002/32/EG of the European Parliament and the Council^[9] on undesirable substances in animal feed. In addition, Commission Recommendation 2002/C 206/01^[10] calls for explicit monitoring of the presence of inorganic arsenic in individual and compound feed.