THIRD WORLD NETWORK BIOSAFETY INFORMATION SERVICE
Dear friends and colleagues,
Re: Toxicity of a glyphosate commercial formulation and its active ingredient
Glyphosate is the most widely used herbicide ingredient worldwide. The most common herbicide formulation includes the brand Roundup. With the introduction of glyphosate tolerant GM crops such as ‘Roundup-Ready’ soy, maize, canola, sugarbeet and cotton, there has been a rapid expansion of the herbicide’s use.
Scientists at GenØk, Centre for Biosafety, which is the national competence centre for biosafety in Norway, conducted experiments with Daphnia magna, an indicator organism for aquatic environments. Their results have been recently published in the journal Ecotoxicology.
They demonstrated that glyphosate and Roundup induce acute toxicity at lower than expected concentrations, which if used as a basis for determining toxicity classification, would reclassify glyphosate from the current “practically nontoxic”, to “toxic” or “moderately toxic” to aquatic invertebrates.
In chronic studies covering the whole life-cycle of D. magna, the scientists demonstrated negative and serious reproduction damage at very low concentrations, i.e. at levels that can be expected with use of the herbicide Roundup at prescribed dosages in agricultural practice.
The results indicate that aquatic invertebrate ecology can be adversely affected by relevant ambient concentrations of this major herbicide. The scientists conclude that glyphosate and Roundup toxicity to aquatic invertebrates have been underestimated and that current European Commission and US EPA toxicity classification of these chemicals need to be revised.
With best wishes,
Third World Network
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Malaysia
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Ecotoxicology (2013) 22article_98551–262
DOI 10.1007/s10646-012-1021-1
Clone- and age-dependent toxicity of a glyphosate commercial formulation and its active ingredient in Daphnia magna
Marek Cuhra • Terje Traavik • Thomas Bøhn
Accepted: 15 November 2012 / Published online: 6 December 2012
© The Author(s) 2012. This article is published with open access at Springerlink.com
M. Cuhra • T. Traavik • T. Bøhn
GenØk, Centre for Biosafety, The Science Park, P.O. Box 6418, 9294 Tromsø, Norway
e-mail: marek.cuhra@gmail.com
M. Cuhra • T. Traavik • T. Bøhn
Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
Abstract
Low levels of glyphosate based herbicide induced significant negative effects on the aquatic invertebrate Daphnia magna. Glyphosate herbicides such as brands of Roundup, are known to be toxic to daphnids. However, published findings on acute toxicity show significant discrepancies and variation across several orders of magnitude. To test the acute effects of both glyphosate and a commercial formulation of Roundup (hereafter Roundup), we conducted a series of exposure experiments with different clones and age-classes of D. magna. The results demonstrated EC50 (48) values in the low ppm-range for Roundup as well as for the active ingredient (a.i.) isopropylamine salt of glyphosate (glyphosate IPA) alone. Roundup showed slightly lower acute toxicity than glyphosate IPA alone, i.e. EC50 values of 3.7–10.6 mg a.i./l, as compared to 1.4–7.2 mg a.i./l for glyphosate IPA. However, in chronic toxicity tests spanning the whole life-cycle, Roundup was more toxic. D. magna was exposed to sublethal nominal concentrations of 0.05, 0.15, 0.45, 1.35 and 4.05 mg a.i./l for 55 days. Significant reduction of juvenile size was observed even in the lowest test concentrations of 0.05 mg a.i./l, for both glyphosate and Roundup. At 0.45 mg a.i./l, growth, fecundity and abortion rate was affected, but only in animals exposed to Roundup. At 1.35 and 4.05 mg a.i./l of both glyphosate and Roundup, significant negative effects were seen on most tested parameters, including mortality. D. magna was adversely affected by a near 100 % abortion rate of eggs and embryonic stages at 1.35 mg a.i./l of Roundup. The results indicate that aquatic invertebrate ecology can be adversely affected by relevant ambient concentrations of this major herbicide. We conclude that glyphosate and Roundup toxicity to aquatic invertebrates have been underestimated and that current European Commission and US EPA toxicity classification of these chemicals need to be revised.