The toxicity of Roundup Original Max® to 13 species of larval amphibians

Abstract

With the increased use of glyphosate-based herbicides (marketed under several names, including Roundup and Vision), there has been a concomitant increased concern about the unintended impacts that particular formulations containing the popular surfactant polyethoxylated tallowamine (POEA) might have on amphibians. Published studies have examined a relatively small number of anuran species (primarily from Australia and eastern North America) and, surprisingly, no species of salamanders. Using a popular formulation of glyphosate (Roundup Original Max), the goal of the present study was to conduct tests of lethal concentrations estimated to kill 50% of a population after 96 h (LC50(96-h)) on a wider diversity of species from both eastern and western North America. Tests were conducted on nine species of stage 25, larval anurans from three families (Ranidae: Rana pipiens, R. clamitans, R. sylvatica, R. catesbeiana, R. cascadae; Bufonidae: Bufo americanus, B. boreas; and Hylidae: Hyla versicolor, Pseudacris crucifer) and four species of larval salamanders from two families (Ambystomatidae: Ambystoma gracile, A. maculatum, A. laterale; and Salamandridae: Notophthalmus viridescens). For the nine species of larval anurans, LC50(96-h) values ranged from 0.8- to 2.0-mg acid equivalents per liter with relatively little pattern in differential sensitivity among the species or families. The four species of larval salamanders were less sensitive than the anurans, with LC50(96-h) values ranging from 2.7- to 3.2-mg acid equivalents per liter and no substantial differences among the species of salamanders. This work substantially increases the available data on amphibian sensitivity to glyphosate formulations that include either POEA surfactants or the equally moderately to highly toxic surfactants of Roundup Original Max and should be useful for improving future risk assessments.

Effects of the herbicide imazapyr on juvenile Oregon spotted frogs

“…This creates uncertainty for land managers who desire to implement its use for habitat restoration in wetlands. In several herbicide studies, the surfactant in the terrestrial formulation is more toxic than the active ingredient [25][26][27]. Although these data are compelling evidence to support concerns associated with the use of more toxic tank mixes in terrestrial habitats where amphibians occur, they are more difficult to interpret in relation to aquatic herbicide tank mixes used in wetland restoration.…”

Re-registration Challenges of Glyphosate in the European Union

“…Roundup R was found to disrupt 17β-estradiol and reduce glutathione concentration in the liver of the endangered fish species delta smelt (Hypomesus transpacificus) upon 6 h of exposure at levels corresponding to 78 µg/l glyphosate concentrations and above (Jin et al, 2018). As described earlier, effects of glyphosate and its formulated products on amphibians and mollusks (Conners and Black, 2004;Mann et al, 2009;Relyea and Jones, 2009;Paganelli et al, 2010;Carrasco, 2013;Meza-Joya et al, 2013;Wagner et al, 2013;Henao Muñoz et al, 2015;Baier et al, 2016a,b) received particular attention due to their known hormonal sensitivity. Differential toxicity of glyphosate and its formulated PPPs have been also considered in the official scientific opinion by EFSA on pesticide risk assessment for amphibians and reptiles (Ockleford et al, 2018).…”

“…Formulated glyphosate-based herbicides, Touchdown R and Roundup R caused neurotoxicity (McVey et al, 2016) as well as locomotion and fertility inhibition (García-Espiñeira et al, 2018) on the nematode Caenorhabditis elegans. Following the results of the late Andrés Carrasco and his research group (Paganelli et al, 2010;Carrasco, 2013), recent findings in environmental toxicology of glyphosate and its formulated products include its revealed toxicity on amphibian species (Mann et al, 2009;Relyea and Jones, 2009;Meza-Joya et al, 2013;Wagner et al, 2013;Henao Muñoz et al, 2015;Baier et al, 2016a,b), on mollusks (Conners and Black, 2004) and on earthworms (Zaller et al, 2014;Gaupp-Berghausen et al, 2015). It affected hemocyte parameters and acetylcholinesterase (AChE) activity, but not antioxidant enzyme activities in mussel Mytilus galloprovincialis (Matozzo et al, 2018) with disruption of key biological processes including energy metabolism, Ca 2+ homeostasis and endoplasmic reticulum stress response, as well as cell signaling identified by transcriptome analysis (Milan et al, 2018).…”

The agricultural impact of pesticides on Physalaemus cuvieri tadpoles (Amphibia: Anura) ascertained by comet assay

“…Among the pesticides applied during the sample collection were glyphosate -Roundup (herbicide), alto-100 (fungicide); dimethoate, MD (insecticide and acaricide); atrazine (herbicide), carbofuran -Furadan (insecticide), Lannate (insecticide) and malathion (pesticide). Indeed, there are several studies with tadpoles, under controlled laboratory conditions, that have drawn attention to the cytotoxic, mutagenic and genotoxic effects of these pesticides and their susceptibility may vary depending on the studied species (Howe et al 2004, Relyea 2005, Relyea and Jones 2009, Bernal et al 2009, Bosch et al 2011, Meza-Joya et al 2013Yadav et al 2013). Our study, however, differs from those in that it measured genomic damages in animals exposed in their natural habitat, in real conditions of contamination.…”