Scientists have said that a type of small organic arsenic species found in some foods can pose a health risk.

The European Food Safety Authority’s (EFSA) risk assessment revealed that exposure to dimethylarsinic acid (DMA) compounds raises a health risk, while monomethylarsonic acid (MMA), does not pose a concern for any age group.

The largest concentrations of these compounds are in rice, algae and seafood. Traces of DMA have been detected in breast milk. The highest chronic dietary exposure to DMA was estimated in toddlers, with rice and fish as the main contributors across population groups.

Experts said that exposure to DMA raises a health risk, particularly for high consumers because of its link to higher bladder cancer rates in rats. However, results of studies with DMA in mice are inconsistent, and do not provide convincing evidence of carcinogenicity.

For MMA, the highest chronic dietary exposures were estimated for high consumers of fish and processed or preserved fish in the infants and elderly age groups.

Findings from part two of four
For other small organoarsenic species, the toxicological data was insufficient, so they were not included in the risk assessment.

Work included literature searches, estimates based on available consumption data, reported occurrence data and feedback from a public comment period.

The European Commission requested four scientific opinions from EFSA on arsenic in food. The first, for inorganic arsenic, was published in January 2024, and the second covers small organoarsenic species. Parts three and four, addressing complex organoarsenic species and combined exposure to inorganic and organic arsenic, are scheduled to be completed by early 2025.

The initial assessment revealed that consumer exposure to inorganic arsenic in food raises health concerns such as skin cancer.

Findings of the latest opinion give the EU Commission a scientific basis if it decides to set maximum levels for MMA and DMA in food. So far no such limits have been established.

Recommendations by EFSA experts included improving analytical methods, continue collecting occurrence data in foods, and to carry out research on the effects of small organoarsenic species.