Effects of Technical Grade and a Commercial Formulation of Glyphosate on Algal Population Growth

Sáenz, María Elena; Marzio, Walter Darío Di; Alberdi, José Luis; Tortorelli, María del Carmen

doi:10.1007/s001289900527

Cited by 50 publications

(28 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, the herbicide not only impacted the tadpoles, but also appears to have affected the periphyton. Previous studies have confirmed the ability of glyphosate to negatively affect algal growth [35,36].…”

Section: Roundup and Amphibians Over Ontogenymentioning

confidence: 77%

Roundup® and amphibians: The importance of concentration, application time, and stratification

Jones

Hammond

Relyea

2010

Enviro Toxic and Chemistry

View full text Add to dashboard Cite

The widespread use of pesticides raises the possibility that non-target organisms might also be affected. To assess this, the traditional approach has been to conduct short-term laboratory experiments spanning a range of lethal concentrations and some longer-duration experiments at sublethal concentrations. While this approach has been very useful, less attention has been paid to the timing of exposure and the impacts of multiple, small exposures versus single, large exposures. We examined the role of application amount, timing, and frequency using outdoor mesocosm communities containing larval amphibians (Rana sylvatica and Bufo americanus) and using a commercial formulation of the herbicide glyphosate (Roundup Original MAX(R)). Consistent with past studies, exposures of up to 3 mg acid equivalent (a.e.)/L caused substantial amphibian death. However, the amount of death was considerably higher when the herbicide was applied earlier in the experiment than later in the experiment. Single, large applications (at different times) had larger effects on tadpole mortality and growth than multiple, small applications (of the same total amount). The results may reflect an acclimation to the herbicide over time. In treatments with high tadpole mortality, there was no resulting increase in periphyton, suggesting that the reduction in tadpole herbivory might have been offset by direct negative impacts of the herbicide. We also discovered that temperature stratification caused herbicide stratification, with higher concentrations near the surface. Such stratification has important implications to the habitat choices of ectotherms that might prefer surface waters for thermoregulation or prefer deeper waters to avoid predators. Collectively, the present study demonstrates the importance of examining multiple applications times and frequencies to understand the impacts of pesticides on organisms.

show abstract

Section: Roundup and Amphibians Over Ontogenymentioning

confidence: 77%

Roundup® and amphibians: The importance of concentration, application time, and stratification

Jones

Hammond

Relyea

2010

Enviro Toxic and Chemistry

View full text Add to dashboard Cite

show abstract

“…Microalgae and crustaceans were four to five-fold more sensitive to Roundup than bacteria and protozoa. 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).…”

Section: Discussionmentioning

confidence: 99%

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

Bonnet¹,

Bonnemoy

Dusser³

et al. 2007

Environmental Toxicology

107

View full text Add to dashboard Cite

ABSTRACT:The potential toxicity of several herbicides-alachlor, diuron and its photo and biotransformation products, glyphosate and its metabolite aminomethyl phosphonic acid (AMPA)-to nontarget cells was assessed using two microorganisms frequently used in ecotoxicology, Vibrio fischeri and Tetrahymena pyriformis. Toxicity assays involved the Microtox 1 test, the T. pyriformis population growth impairment test employing three different processes (flasks, tubes, microplates), and the T. pyriformis nonspecific esterase activities test. Several IC 50 or EC 50 values are reported for each molecule. Alachlor exerted a toxic effect on the two nontarget cells used. The results for diuron and its photo and biotransformation products indicated that most of the metabolites presented nontarget toxicity higher than that of diuron. Glyphosate and AMPA had a less negative effect on T. pyriformis than on V. fischeri. Nevertheless, in all cases, glyphosate was found to be more toxic than AMPA. Comparison analysis of the sensitivity of the different tests showed that, in general, tests using the eukaryotic cell (T. pyriformis) were more sensitive than test using the prokaryotic cell (V. fischeri), and that a population growth criterion is more sensitive than an enzymatic criterion. The three different processes that could be used to evaluate effects on population growth rate were equally sensitive for the herbicides tested. A significant correlation between toxicity data and the hydrophobicity of the chemicals could only be established with the growth population test. This study demonstrates that it is essential to assess the toxicity of the metabolites formed to complete a more comprehensive study of the environmental impact of a polluting agent. # 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 78-91, 2007.

show abstract

“…These wide differences could arise as a result of differences in study design, such as the duration of the experiments, the glyphosate formulation used (e.g. Sáenz et al, 1997), which is not always clearly identified, and the EC 50 measurements, which may be based on the biomass, the chlorophyll concentration, or on the carbon uptake. In the same way, the Cyanobacteria, which are photosynthetic prokaryotes, exhibited a wide range of EC 50 values varying from 2 to 1183 mg/L.…”

Section: Impact Of Glyphosate On Aquatic Microorganismsmentioning

confidence: 99%

Herbicide Contamination of Freshwater Ecosystems: Impact on Microbial Communities

Villeneuve¹,

Larroudé²,

Humbert³

2011

Pesticides - Formulations, Effects, Fate

View full text Add to dashboard Cite

Effects of Technical Grade and a Commercial Formulation of Glyphosate on Algal Population Growth

Cited by 50 publications

References 10 publications

Roundup® and amphibians: The importance of concentration, application time, and stratification

Roundup® and amphibians: The importance of concentration, application time, and stratification

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

Herbicide Contamination of Freshwater Ecosystems: Impact on Microbial Communities

Contact Info

Product

Resources

About