The Toxicity of Glyphosate and Several Glyphosate Formulations to Four Species of Southwestern Australian Frogs

Abstract

The acute toxicity of technical-grade glyphosate acid, glyphosate isopropylamine, and three glyphosate formulations was determined for adults of one species and tadpoles of four species of southwestern Australian frogs in 48-h static/renewal tests. The 48-h LC50 values for Roundup(R) Herbicide (MON 2139) tested against tadpoles of Crinia insignifera, Heleioporus eyrei, Limnodynastes dorsalis, and Litoria moorei ranged between 8.1 and 32.2 mg/L (2.9 and 11.6 mg/L glyphosate acid equivalent [AE]), while the 48-h LC50 values for Roundup(R) Herbicide tested against adult and newly metamorphosed C. insignifera ranged from 137-144 mg/L (49.4-51.8 mg/L AE). Touchdown(R) Herbicide (4 LC-E) tested against tadpoles of C. insignifera, H. eyrei, L. dorsalis, and L. moorei was slightly less toxic than Roundup(R) with 48-h LC50 values ranging between 27.3 and 48.7 mg/L (9.0 and 16.1 mg/L AE). Roundup(R) Biactive (MON 77920) was practically nontoxic to tadpoles of the same four species producing 48-h LC50 values of 911 mg/L (328 mg/L AE) for L. moorei and >1,000 mg/L (>360mg/L AE) for C. insignifera, H. eyrei, and L. dorsalis. Glyphosate isopropylamine was practically nontoxic, producing no mortality among tadpoles of any of the four species over 48 h, at concentrations between 503 and 684 mg/L (343 and 466 mg/L AE). The toxicity of technical-grade glyphosate acid (48-h LC50, 81.2-121 mg/L) is likely to be due to acid intolerance. Slight differences in species sensitivity were evident, with L. moorei tadpoles showing greater sensitivity than tadpoles of the other four species. Adult and newly emergent metamorphs were less sensitive than tadpoles.

Assessment of the potential toxicity of herbicides and their degradation products to nontarget cells using two microorganisms, the bacteria Vibrio fischeri and the ciliate Tetrahymena pyriformis

“…Effects of glyphosate and commercial formulations on plants and algae have been reported in the literature (Sáenz et al, 1997;Ma et al, 2002;Cedergreen and Streibig, 2005;Agritox, 2006;Ma et al, 2006;Pettersson and Ekelund, 2006;Toxnet, 2006). The toxicity of glyphosate has also been studied in a range of organisms including fish (salmon, trout, catfish), aquatic invertebrates (daphnids, midge's larvae) and ciliated protozoa (T. thermophila, Ichthyophthirius multililiis) (Folmar et al, 1979;Servizi et al, 1987;Mann and Bidwell, 1999;Everett and Dickerson, 2003;Agritox, 2006). A few values have been reported for ecotoxicity of the metabolite AMPA on fish, algae, and invertebrates (Agritox, 2006), indicating that AMPA is less toxic than glyphosate.…”

“…Ecotoxicological values have been determined for glyphosate and AMPA (Agritox, 2006;Toxnet, 2006). Multiple studies have found that commercial glyphosate-based formulations are more toxic to aquatic organisms than glyphosate itself (Folmar et al, 1979;Servizi et al, 1987;Mann and Bidwell, 1999;Everett and Dickerson, 2003;Tsui and Chu, 2003) because of the surfactants present in the formulations. AMPA is thought to be equally or less toxic than glyphosate (Carlisle and Trevors, 1988;Giesy et al, 2000).…”

Ecotoxicidade de herbicidas para a macrófita aquática (Azolla caroliniana)

“…A caracterização de um bioindicador requer uma série de informações sobre sensibilidade, ciclo reprodutivo, facilidade de operação e custo de otimização (Mann & Bidwell, 1999).…”

“…Devido à acentuada sensibilidade, as macrófitas aquáticas são utilizadas nos estudos ecotoxicológicos com herbicidas (Mann & Bidwell, 1999). De acordo com Lumpkin & Pluckneet (1980), Azolla sp.…”

Ecotoxicidade comparativa dos herbicidas da cana-de-acúcar para larvas de anfíbios

“…Por exemplo, glifosato é o herbicida mais usado no mundo, em termos de volume (20%; ARMAS et al, 2005), mas poucos são os estudos que avaliam a toxicidade aguda do ingrediente ativo glifosato (BIDWELL & GORRIE, 1995;MANN & BIDWELL, 1999;LAJMANOVICH et al, 2003;HOWE et al, 2004;BERNAL et al, 2009 Além da escassez de trabalhos que avaliem a toxicidade aguda dos ingredientes ativos investigados nesta dissertação a anfíbios, diversos fatores influenciam de forma significativa a toxicidade de compostos e sua comparação, como o tempo de exposição, o regime de renovação das soluções-teste, a forma de manipulação do composto -se ingredientes ativo ou se formulação, e o estágio de desenvolvimento inicial dos indivíduos, entre outros. Por todos estes motivos, esta revisão evidencia, mais uma vez, a importância da utilização de experimentos ecotoxicológicos padronizados de exposição aguda como ferramenta para a avaliação da variação interespecífica da sensibilidade e do nível de ecotoxicidade de xenobióticos à organismos.…”