ANSES has just increased the threshold in drinking water from 0.1 to 0.9 g/l for the metabolite chlorothalonil. In contrast, the Swiss authorities had to defend themselves against Syngenta for respecting the 0.1 g/l limit.
It is the first phytosanitary metabolite that is most often found (1) in drinking water from Anational agency for health security (Anses): The status of chlorothalonil R 471811 has just been changed, which will change the management of the resource. Until now considered a relevant metabolite, which means that it may pose a health risk, (2) the limit that must not be exceeded in order to maintain the quality of drinking water is set at 0.1 micrograms per liter (g/l). But new
after receiving additional studies on the active substance at the end of June 2023, the health authority assessed (3) classification of this metabolite. Result? In this new light, the metabolite is now classified as unimportant with a less stringent threshold being respected, 0.9 g/l instead of 0.1 g/l. Another implication: it will no longer be integrated into the calculation of the total pesticide threshold that must not be exceeded (fixed at 0.5 g/l). All situations for which R471811 was found in drinking water at concentrations between 0.1 g/L and 0.9 g/L become “compliant” again. regrets the association Générations Futures. This new classification will provide better statistics on drinking water compliance rates.
Last October, the same decrease in metabolites Smtolachlor ESAthe second most frequently found substance, caused the same disapproval of the association.
Active substance, which is considered allegedly carcinogenic
What changed the decision for Chlorothalonil R 471811 are new studies showing that this metabolite does not have the same mode of action as its active substance, which is classified as a human carcinogen at the European level. (4) . A classification for which the European Safety Agency (EFSA) would like to strengthen as an alleged carcinogen (5) . As usual, additional data for arbitration was provided by Syngenta, one of the companies that marketed phytopharmaceuticals containing the active substance chlorothalonil. In Europe, activity is now taking place because from 2020, products containing it can no longer be used on European soil. The Commission did not renew the approval of the active substance. () it is impossible to determine to date that the presence of chlorothalonil metabolites in groundwater will not have harmful effects on human health or unacceptable effects on the said water, specifically explained this in its implementing regulations (6) . Furthermore, (EFSA) could not rule out a genotoxicity problem related to residues to which consumers will be exposed and highlighted the existence of a high risk to amphibians and fish for all uses assessed.
Conflict with Syngenta in Switzerland
In France, chlorothalonil R 471811 is distinguished by another characteristic: it is, like S-Mtolachlor, one of the contaminants that reduces quality L‘drinking water. The latest ANSES national campaign on emerging contaminants shows that 34% of drinking water samples exceeded the limit of 0.1 g/l. This is a headache for the communities responsible for the production of drinking water in France, but also among our Swiss neighbors.
Namely, in Switzerland in 2017, the widespread presence of this metabolite was discovered for the first time. En 2019, aafter ordering drinking water distributors to respect the threshold of 0.1 g/l revoked the approval of chlorothalonil from 1.this one January 2020. The Swiss Federal Office for Food Safety (OSAV) found itself before the administrative court. Syngenta disputes this threshold and wants to reverse the withdrawal of authorization.
Chloridazone metabolites, relevant and declassifying
In the ranking of the top five most non-conforming metabolites, which are still considered relevant, two chloridazone derivatives now remain: desphenyl-chloridazone (DPC) and methyl-desphnylchloridazone (MDPC).
In February 2021, the first interim decision of the Federal Administrative Court required the Office to refrain from communicating the toxicological significance of chlorothalonil metabolites. The final decision, made last March, did not retain this restriction. Osav is now again authorized to officially communicate the maximum value set for the degradation products of chlorothalonil , the health authority was pleased. Final arbitration is still pending for the cancellation of the authorization.
when is there transparency in data production?
This case highlights the issue of developing data that enable status arbitrage pesticides and their metabolites. THE data ANSES is often provided with data from the manufacturer of the active substance, recorded during the Astee Webinar on Pesticides, Christophe Mechouk, former member of the expert board of Anses Water, and now manager, specialist in water treatment. There are very few 100% independent studies. We can ask a question about transparency manufacturers. The latter reminds us of the importance of creating a European fund to which industrialists would contribute and which would then be financed independent studies.
This situation calls into question the possibility of financing in-depth studies on prohibited substances and their residues. It is necessary to really think about how to unblock these situations in view of the general interest that would consist of the possibility of accumulating knowledge, assesses Laurent Brunet, co-leader of the Astee pesticide working group.Even if we think from the point of view of global costs, the costs of the studies carried out would be infinitely lower than the costs of treating everything, because we think that this molecule is relevant.
Article published on May 24, 2024