Increased severity associated with tallowamine in acute glyphosate poisoning.

Context: During the re-approval process of glyphosate in Europe, it was mentioned that glyphosate-based products (GBF) were more toxic than glyphosate alone. This phenomenon was attributed to the surfactants and among them, polyethoxylated tallowamine (POEA) has been suspected to significantly contribute to the toxicity of glyphosate products. In animal data acute oral toxicity of POEA has been suggested to be greater than glyphosate toxicity in animal studies. There are no data, however, comparing the clinical signs and severity of acute human poisoning with tallowamine-containing GBF (TA) and non-tallowamine-containing GBF (NTA). The aim of this study was to compare the severity of oral poisoning between TA and NTA cases, reported to the French Poison Control Centres (PCC) over 7 years.Methods: This is a retrospective study of cases of oral exposure to GBF reported to French PCCs between January 1st, 2008 and December 12th, 2014. The formulation of every GBF was reviewed using the PCC national database of products and compositions, to identify cases involving TA, NTA, or GBF with unknown co-formulants.Results: Between 2008 and 2014, 1362 cases of GBF ingestion were registered in the PCC national database of poisoning cases. Among them, 429 were symptomatic acute cases of ingestion of GBF. There were 235 exposures to TA, 105 to NTA, and 89 to unknown GBF. There were more severe cases in the TA group than in the NTA group (p = 0.037).Discussion: The present study shows that POEA rather than other co-formulants leads to more severe symptoms in those patients ingesting GBF. The acute toxicity of POEA might be explained by its irritating properties; in experimental studies, it caused skin irritation and severe eye and mucous membranes irritation.Conclusion: In this study, severe respiratory symptoms were also more frequently reported in the TA group. The surfactant properties of POEA are likely to cause aspiration pneumonitis which is a plausible explanation for the respiratory failure complicating severe GBF poisoning cases.

Toxicity of formulants and heavy metals in glyphosate-based herbicides and other pesticides.

The major pesticides of the world are glyphosate-based herbicides (GBH), and their toxicity is highly debated. To understand their mode of action, the comparative herbicidal and toxicological effects of glyphosate (G) alone and 14 of its formulations were studied in this work, as a model for pesticides. GBH are mixtures of water, with commonly 36-48% G claimed as the active principle. As with other pesticides, 10-20% of GBH consist of chemical formulants. We previously identified these by mass spectrometry and found them to be mainly families of petroleum-based oxidized molecules, such as POEA, and other contaminants. We exposed plants and human cells to the components of formulations, both mixed and separately, and measured toxicity and human cellular endocrine disruption below the direct toxicity experimentally measured threshold. G was only slightly toxic on plants at the recommended dilutions in agriculture, in contrast with the general belief. In the short term, the strong herbicidal and toxic properties of its formulations were exerted by the POEA formulant family alone. The toxic effects and endocrine disrupting properties of the formulations were mostly due to the formulants and not to G. In this work, we also identified by mass spectrometry the heavy metals arsenic, chromium, cobalt, lead and nickel, which are known to be toxic and endocrine disruptors, as contaminants in 22 pesticides, including 11 G-based ones. This could also explain some of the adverse effects of the pesticides. In in vivo chronic regulatory experiments that are used to establish the acceptable daily intakes of pesticides, G or other declared active ingredients in pesticides are assessed alone, without the formulants. Considering these new data, this assessment method appears insufficient to ensure safety. These results, taken together, shed a new light on the toxicity of these major herbicides and of pesticides in general.