Paris (France) (AFP) – It is found in fertilizers but also naturally in soils: cadmium, a heavy metal, is present in many foods via the contamination of agricultural soils which are very complicated to decontaminate, according to researchers and industrialists.

Published on: 04/21/2026 - 12:05

In a report published in March, the health agency Anses confirms that food is in France the main source of exposure to cadmium, a metal toxic to reproduction and carcinogenic in the event of prolonged exposure.

The agency recommends reducing the cadmium content of phosphate mineral fertilizers and taking action to “sustainably reduce soil contamination”.

If the content is linked to the very nature of the soils - it is higher on limestone rocks such as in Champagne, Charente or Jura - "today, the quantity of cadmium which enters the soils comes 50 to 70% from phosphate fertilizers", underlines Thibault Sterckeman, researcher at the National Research Institute for Agriculture, Food and the Environment (Inrae).

But, he adds, "these incoming flows - between 0.5 and 1 gram per hectare per year - represent only 0.1% of the total stock of cadmium in the soil".

“Because most of the cadmium present is old: essentially due to the nature of the soil, to atmospheric pollution linked to industrial activity (mines, foundries, etc.), for example around the Nord-Pas-de-Calais mining basin, and to phosphate fertilizers introduced in the 20th century,” he adds.

Even if the contribution linked to phosphate fertilizers is "fairly low", "if this contribution remains constant, in 100 years it will correspond to around 10% of the current stock in the soil", which explains the desire to limit this pollution, he explains.

"Experimental stage"

But is it possible to decontaminate soil?

“We have a lot of technologies to clean up the soil” of heavy metals, including cadmium, told AFP Rémi Muth, technical director of the depollution branch of Séché Environnement, a company specializing in waste management.

But, he adds, they are not suitable for agricultural soils. Particularly because this work “often requires heavy resources”, with processing times “not very compatible with an agricultural operation”, which would see its cultivable areas reduced. But also because the treatment itself can weaken or kill the organic matter in the soil.

As for decontamination using plants, it is "still at the experimental stage", observes Thibault Sterckeman, who concludes: "the decontamination of agricultural soils in France is not for tomorrow".

A 2013 study by the environment agency Ademe and the National Institute of Industrial Environment and Risks (Ineris) already studied “phytotechnologies applied to polluted sites and soils”.

According to this report, the species to be used can be "hyperaccumulator" plants of pollutants, which store a lot in their aerial part - but these plants are "uncommon in the plant kingdom" and "slow-growing". Or “accumulator” plants with “high biomass”, which compensate for an average concentration with rapid growth.

The study underlines that local species "with a short or perennial cycle" should be favored to allow several harvests of aerial parts enriched in pollutants during the year; but also “unattractive” plants, which are not eaten by herbivores such as cattle, which would risk bringing pollution back into the food chain.

Accumulate less

Several studies suggest a wild cruciferous plant (Noccaea caerulescens) which has a high capacity for cadmium accumulation. But, notes Thibault Sterkeman, it “would not allow us to clean up pollution quickly enough because it produces little dry matter”.

Furthermore, underlines the researcher, “we do not have the means to treat a huge quantity of contaminated dry matter”.

Limiting the use of synthetic fertilizers, already reduced by 70% since the 1980s, remains one of the main recommendations of Inrae, which calls for nitrogen or phosphorus-fixing plants (legumes, white lupine, buckwheat, etc.) to be introduced into crop rotations instead.

At the same time, the best solution to reduce exposure to cadmium consists of developing varieties of plants that accumulate it less, underlines Inrae.

The institute mentions promising avenues, particularly for durum wheat with the identification by Canadian researchers of a gene which "promotes the retention of cadmium in the roots", ultimately giving seeds containing "2 to 3 times less" cadmium than another variety.

© 2026 AFP

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