The case had caused the banning of this pesticide in France. This Monday opens the trial before the criminal court of Angers of the Nantes company Primaloire and one of its employees, accused of involuntary injuries after the intoxication of several dozen people with metam-sodium. The Primaloire employee allegedly used it inappropriately in the fall of 2018, causing intense head pain and breathing difficulties to students at a nearby high school, then to around sixty farm workers. Some had to be taken to the emergency room of the CHU d’Angers.
Following the incident, the National Agency for Food, Environmental and Occupational Health and Safety (Anses) took care to “reassess the files”, before deciding “to withdraw all of the marketing authorizations for metam sodium products’. “After reassessment, ANSES concludes that all of these uses represent a risk for human health and the environment”, had thus communicated the Agency on November 5, 2018, explaining that “although they are applied to small areas in the open field or in greenhouses”, these products “needed to be used in large quantities to act effectively”.
Used in market gardening or horticulture, phytopharmaceutical products based on metam-sodium are used by fumigation, that is to say by the smoke of chemical substances, to disinfect the soil. A clear, colorless liquid, usually sold as a solution, it is applied directly to the ground before crops are planted, sometimes under a tarp to allow the product to penetrate the soil as well as possible. It contains a high concentration of the active substance, which is an organic compound called dimethyl sulfide, capable of killing pests as well as weeds.
And for it to be effective, it must be applied in high doses. So much so that, according to ANSES, “the dose of use is between 300 and 1200 liters per hectare, which represents nearly 700 tonnes used each year in France”. In the United States, it is even – according to figures from the Environmental Protection Agency (EPA) – one of the most widely used pesticides in the agricultural sector, but also for arboriculture and floral horticulture, nursery or when preparing or restoring golf course turf. If its use is still authorized across the Atlantic, it is still strictly prohibited in the immediate vicinity of homes.
The health risks are indeed high. In the event of skin contact, for example, appears “a sometimes painful burning sensation, pruritus, erythema”, which “can evolve into a bullous eruption of the second degree burn type” if there has been prolonged contact, explains ANSES. While in the event of exposure to vapors, it is rather “signs of irritation of the skin and mucosa, eye and aerodigestive tract (dyspnea, tracheal irritation, epigastralgia, nausea, vomiting)” which can cause some discomfort. Worse, “in the event of prolonged and repeated exposure over several days, systemic signs may occur (headaches, dizziness, asthenia, bradycardia, hypotension)”.
Among the main risk factors, the National Health Security Agency cites the absence of personal protective equipment (PPE), “the main risk factor for the occurrence of adverse effects”. The mode of application such as “the use of a defective backpack sprayer, or even a watering can, application by tractor with an open or closed unventilated cabin can also be a source of significant exposure”, warns the Anses, which warns about “prolonged and repeated exposure, several consecutive days, to a high ambient temperature”. Likely, according to her “to lead to systemic effects in addition to an exacerbation of local effects”.
As a reminder, metam-sodium was banned by the European Union in 2009, after the publication of a report by the European Food Safety Authority (EFSA) pointing out its many dangers. At the time, the conclusions of the EFSA already mentioned risks for the populations settled downwind of the injections, for the fauna in general as well as for the underground water tables. Despite this, fifteen European states, including France, had continued to use it by way of derogation. Until the end of 2018 therefore.
