| Reference | [1]. Tush, D., Maksimowicz, M.M. and Meyer, M.T., 2018.<br />
Dissipation of polyoxyethylene tallow amine (POEA) and glyphosate in an agricultural field and their co-occurrence on streambed sediments.<br />
Abstract: The environmental fate of polyoxyethylene tallow amine (POEA), an additive in glyphosate herbicide formulations, has not been studied. This study examined the dissipation of POEA; glyphosate; and aminomethylphosphonic acid (AMPA), a degradation product of glyphosate, in the top 45 cm of soil from an agricultural field where glyphosate was applied. The concentration of these compounds was also analyzed in bed sediment samples from watersheds in agricultural and urban areas from six states (Georgia, Hawaii, Iowa, Mississippi, North Carolina, South Carolina). The field studies show that POEA, glyphosate, and AMPA persist on the soil from planting season to planting season but dissipate over time with little migration into deeper soil. POEA, glyphosate, and AMPA were found on the bed sediment samples in urban and agricultural watersheds.<br />
Science of the Total Environment, 636, pp.212-219. [2]. Tush, D., Loftin, K.A. and Meyer, M.T., 2013.<br />
Characterization of polyoxyethylene tallow amine surfactants in technical mixtures and glyphosate formulations using ultra-high performance liquid chromatography and triple quadrupole mass spectrometry.<br />
Abstract: Little is known about the occurrence, fate, and effects of the ancillary additives in pesticide formulations. Polyoxyethylene tallow amine (POEA) is a non-ionic surfactant used in many glyphosate formulations, a widely applied herbicide both in agricultural and urban environments. POEA has not been previously well characterized, but has been shown to be toxic to various aquatic organisms. Characterization of technical mixtures using ultra-high performance liquid chromatography (UHPLC) and mass spectrometry shows POEA is a complex combination of homologs of different aliphatic moieties and ranges of ethoxylate units. Tandem mass spectrometry experiments indicate that POEA homologs generate no product ions readily suitable for quantitative analysis due to poor sensitivity. A comparison of multiple high performance liquid chromatography (HPLC) and UHPLC analytical columns indicates that the stationary phase is more important in column selection than other parameters for the separation of POEA. Analysis of several agricultural and household glyphosate formulations confirms that POEA is a common ingredient but ethoxylate distributions among formulations vary.<br />
Journal of Chromatography A, 1319, pp.80-87.<br />
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[3]. Mesnage, R., Benbrook, C. and Antoniou, M.N., 2019.<br />
Insight into the confusion over surfactant co-formulants in glyphosate-based herbicides.<br />
Abstract: Glyphosate is the active ingredient in glyphosate-based herbicides (GBHs). Other chemicals in GBHs are presumed as inert by regulatory authorities and are largely ignored in pesticide safety evaluations. We identified the surfactants in a cross-section of GBH formulations and compared their acute toxic effects. The first generation of polyethoxylated amine (POEA) surfactants (POE-tallowamine) in Roundup are markedly more toxic than glyphosate and heightened concerns of risks to human health, especially among heavily-exposed applicators. Beginning in the mid-1990s, first-generation POEAs were progressively replaced by other POEA surfactants, ethoxylated etheramines, which exhibited lower non-target toxic effects. Lingering concern over surfactant toxicity was mitigated at least in part within the European Union by the introduction of propoxylated quaternary ammonium surfactants. This class of POEA surfactants are ∼100 times less toxic to aquatic ecosystems and human cells than previous GBH-POEA surfactants. As GBH composition is legally classified as confidential commercial information, confusion concerning the identity and concentrations of co-formulants is common and descriptions of test substances in published studies are often erroneous or incomplete. In order to resolve this confusion, laws requiring disclosure of the chemical composition of pesticide products could be enacted. Research to understand health implications from ingesting these substances is required.<br />
Food and Chemical Toxicology, 128, pp.137-145.<br />
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[4]. Mesnage, R., Bernay, B. and Séralini, G.E., 2013.<br />
Ethoxylated adjuvants of glyphosate-based herbicides are active principles of human cell toxicity.<br />
Abstract: Pesticides are always used in formulations as mixtures of an active principle with adjuvants. Glyphosate, the active ingredient of the major pesticide in the world, is an herbicide supposed to be specific on plant metabolism. Its adjuvants are generally considered as inert diluents. Since side effects for all these compounds have been claimed, we studied potential active principles for toxicity on human cells for 9 glyphosate-based formulations. For this we detailed their compositions and toxicities, and as controls we used a major adjuvant (the polyethoxylated tallowamine POE-15), glyphosate alone, and a total formulation without glyphosate. This was performed after 24 h exposures on hepatic (HepG2), embryonic (HEK293) and placental (JEG3) cell lines. We measured mitochondrial activities, membrane degradations, and caspases 3/7 activities. The compositions in adjuvants were analyzed by mass spectrometry. Here we demonstrate that all formulations are more toxic than glyphosate, and we separated experimentally three groups of formulations differentially toxic according to their concentrations in ethoxylated adjuvants. Among them, POE-15 clearly appears to be the most toxic principle against human cells, even if others are not excluded. It begins to be active with negative dose-dependent effects on cellular respiration and membrane integrity between 1 and 3 ppm, at environmental/occupational doses. We demonstrate in addition that POE-15 induces necrosis when its first micellization process occurs, by contrast to glyphosate which is known to promote endocrine disrupting effects after entering cells. Altogether, these results challenge the establishment of guidance values such as the acceptable daily intake of glyphosate, when these are mostly based on a long term in vivo test of glyphosate alone. Since pesticides are always used with adjuvants that could change their toxicity, the necessity to assess their whole formulations as mixtures becomes obvious. This challenges the concept of active principle of pesticides for non-target species.<br />
Toxicology, 313(2-3), pp.122-128.<br />
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[5]. Köcher, H. and Kocur, J., 1993.<br />
Influence of wetting agents on the foliar uptake and herbicidal activity of glufosinate.<br />
Abstract: The influence of four different wetting agents on the foliar retention, uptake and herbicidal activity of the glutamine synthetase inhibitor, glufosinate, was examined in growth-chamber experiments on barley (Hordeum vulgare L. cv Roland) and barnyard grass (Echinochloa crus-galli (L.) P.B.) as test species. The non-formulated monoammomum salt, glufosinate-ammonium, was applied as a spray, either alone or mixed with a wetting agent. The dose rates of herbicide and wetting agent were 0.5 g a.i. litre−1 and 2.0 g litre−1, respectively, on barnyard grass, and 2.0 g a.i. litre−1 and 60 g litre−1, respectively, on barley. Herbicide damage, rated 10 days after spraying, was greatest when glufosinate was used with a sodium C12/C14-alcohol-diglycolether sulfate (FAEO-sulfate) and least with polyoxyethylene (POE)(8) tridecyl ether; intermediate effectiveness was obtained with a combination of herbicide and a POE(15) tridecyl ether or POE(15)-tallow amine. The activity of the target enzyme, glutamine synthetase, measured 2 h after spraying, was reduced most when FAEO-sulfate was present and least with POE(8) tridecyl ether. The behaviour of the glufosinate wetting agent solutions on plant foliage was analysed by measurements of spray retention, droplet contact angles and foliar uptake of [14C]glufosinate. The results led, for both grass species, to the conclusion that differential ability of the wetting agents to enhance the permeation of glufosinate from the leaf surface deposit into the leaf tissue was the main factor responsible for the differences in herbicidal effectiveness of the glufosinate/wetting agent combinations used in this study.<br />
Pesticide science, 37(2), pp.155-158.
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