An innovative method to more accurately measure dietary exposure to arsenic
Some forms of arsenic are toxic and even carcinogenic. ANSES’s Laboratory for Food Safety has developed an innovative method that will enable their concentration in different foods to be more accurately measured. This breakthrough will enhance the assessment of consumer exposure and health risks.
Measuring the different forms of arsenic in various foods
Arsenic is both naturally occurring in soil and released into the environment as a result of human activities, particularly industrial production. It can be found in food and drinking water.
As the toxicity of arsenic depends on its chemical form, it is important to measure the levels of the various forms in food to better protect human health. To this end, the Trace Elements and Nanomaterials Unit of ANSES’s Laboratory for Food Safety has developed and validated a new analytical method that can identify and quantify the various chemical forms of arsenic, also referred to as species, in a wide variety of foods.
This method can distinguish between four species of arsenic: two inorganic species – arsenic(III) (arsenite) and arsenic(V) (arsenate) – and two organic species – monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). Inorganic arsenic species, such as arsenite and arsenate, are known to be carcinogenic and particularly toxic. Complex organic forms are considered less toxic in the current state of knowledge. However, recent data show that small organoarsenic compounds such as MMA and DMA may be toxic, and that this is particularly true for DMA, which may be associated with an increased incidence of cancer.
The analytical methods available up to now were only able to partially or imprecisely quantify the various arsenic species and could only be used for certain food groups: “There is an official ‘standard’ method for determining the inorganic arsenic content of seafood products and plants, but it measures the overall concentration, without distinguishing between species. Moreover, there is no standardised method for determining organic arsenic species” affirms Axelle Leufroy, project manager and co-supervisor of the thesis that led to the development of the new method. “We have adapted and optimised the official method to extend it to other food groups and other arsenic species. It is based on a liquid chromatography technique, which separates the species, combined with inductively coupled plasma mass spectrometry (ICP-MS) to detect them”.
A practical application to better understand the exposure of the population
“This method was developed as part of a PhD project in connection with the third French Total Diet Study (TDS3) undertaken by ANSES” explains Petru Jitaru, Head of the Trace Elements and Nanomaterials Unit and director of the thesis. “We have successfully applied it to the analysis of around 300 samples belonging to 19 of the food groups most commonly consumed in France, including prepared dishes, beverages (alcoholic drinks, fruit juices, hot beverages, etc.), cereals, fruit, biscuits, bread, vegetables and seafood products”. Around 130 of these samples were organic while 165 were conventionally grown.
The method developed will help to refine the evaluation of the population's exposure to arsenic species and will also lead to a more accurate assessment of health risks, rather than relying on theoretical estimates, as is usually the case. Similar work focusing on other elements, such as mercury and chromium, has also been carried out as part of the thesis project.