Adsorption, Mobility, and Microbial Degradation of Glyphosate in the Soil

Sprankle, Paul; Meggitt, W. F.; Penner, Donald

doi:10.1017/s0043174500052929

Cited by 431 publications

(343 citation statements)

References 13 publications

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“…A better sorption capacity is peculiar of soils with a high content of clay compared to e.g. its sandy types (Sprankle et al 1975). Organic matter can contribute to GP sorption by formation of mineral-organic complexes (Piccolo et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Glyphosate bioavailability in soil

2009

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Biodegradation of glyphosate in sod-podzol soil by both the indigenous micro flora and the introduced strain Ochrobactrum anthropi GPK 3 was studied with respect to its sorption and mobility. The experiments were carried out in columns simulating the vertical soil profile. Soil samples studied were taken from soil horizons 0-10, 10-20, and 20-30 cm deep. It was found out that the most of the herbicide (up to 84%) was adsorbed by soil during the first 24 h; the rest (16%) remained in the soluble fraction. The adsorbed glyphosate was completely extractable by alkali. No irreversible binding of glyphosate was observed. By the end of the experiment (21st day), glyphosate was only found in extractable fractions. The comparison of the effect of the introduced O. anthropi GPK 3 and indigenous microbial community on the total toxicant content (both soluble and absorbed) in the upper 10 cm soil layer showed its reduction by 42% (21 mg/kg soil) and 10-12% (5 mg/kg soil), respectively. Simultaneously, 14-18% glyphosate moved to a lower 10-20 cm layer. Watering (that simulated rainfall) resulted in a 20% increase of its content at this depth; 6-8% of herbicide was further washed down to the 20-30 cm layer. The glyphosate mobility down the soil profile reduced its density in the upper layer, where it was available for biodegradation, and resulted in its concentration in lower horizons characterized by the absence (or low level) of biodegradative processes. It was shown for the first time how the herbicide biodegradation in soil can be increased manifold by introduction of the selected strain O. anthropi GPK 3.

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Section: Introductionmentioning

confidence: 99%

Glyphosate bioavailability in soil

2009

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“…Degradation of glyphosate in soil is mainly a microbiological process (e.g. Sprankle et al 1975b;Torstensson 1985;Carlisle and Trevors 1988). The main metabolites are aminomethyl phosphonic acid (AMPA) and sarcosine, depending on the degradation path.…”

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confidence: 99%

Glyphosate and phosphorus leaching and residues in boreal sandy soil

et al. 2009

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Glyphosate [(N-(phosphonomethyl)glycine)] is a widely used herbicide and it is known to compete for the same sorption sites in soil as phosphorus. Persistence and losses of glyphosate were monitored in a field with low phosphorus status and possible correlation between glyphosate and phosphorus leaching losses was studied. Glyphosate and its metabolite AMPA (aminomethyl phosphonic acid) residues in soil samples were analysed after a single application in autumn. Twenty months after the application the residues of glyphosate and AMPA in the topsoil (0-25 cm) corresponded to 19% and 48%, respectively, of the applied amount of glyphosate, and traces of glyphosate and AMPA residues were detected in deeper soil layers (below 35 cm). These results indicate rather long persistence for glyphosate in boreal soils. Surface runoff and subsurface drainflow were collected continuously all year round for 20 months and analysed for glyphosate, AMPA, dissolved phosphate, total phosphorus and total suspended solids.The glyphosate concentrations in the surface runoff water were highest, with 99% of the total leaching losses obtained, during the periods of snow melting and soil thawing in the first winter following the autumn application. The total leaching of glyphosate was 5.12 g ha −1 and that of AMPA 0.48 g ha −1 , corresponding to about 0.51% and 0.07%, respectively, of the applied amount of glyphosate. No residues of glyphosate and AMPA were detected in the subsurface drainflow. The correlations between concentrations of glyphosate and dissolved orthophosphate as well as glyphosate and total phosphorus in surface runoff were significant (p<0.01).

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“…Glyphosate is rapidly adsorbed on soils, practically immobile in soils, volatilization does not occur and leaching is practically negligible, but disappearance through degradation is often slow with half-lives ranging from a few days to several months or years (Sprankle et al 1975;Rueppel et al 1977), so that toxicology must be evaluated. Due to its high soil adsorption coefficient (2,100 mL g -1 ) (Durkin 2003), glyphosate has a very low potential risk of leaching and ground water contamination on valencian citrus orchards (De Paz and Rubio 2006) but excess water from citrus orchards, and eventually glyphosate residues, can travel to the lake of the ANP through the rice fields due to its high water solubility (12 g L -1 ).…”

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confidence: 99%

Effect of Glyphosate on Growth of Four Freshwater Species of Phytoplankton: A Microplate Bioassay

Vendrell

Barreda

Sabater

et al. 2009

Bull Environ Contam Toxicol

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The acute toxicity of glyphosate herbicide was tested on the four species of freshwater phytoplankton, Scenedesmus acutus, Scenedesmus subspicatus, Chlorella vulgaris and Chlorella saccharophila. Herbicide concentrations eliciting a 50% growth reduction over 72 h (EC(50)) ranged from 24.5 to 41.7 mg L(-1), whilst a 10% growth inhibition is achieved by herbicide concentrations ranging from 1.6 to 3.0 mg L(-1), difficult to find neither in paddy fields (it is not used in rice) nor in the lake of the Albufera Natural Park. Chorella species are less sensitive to the herbicide than Scenedesmus species. It can be concluded that glyphosate has a low potential risk for the tested organisms.

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Adsorption, Mobility, and Microbial Degradation of Glyphosate in the Soil

Cited by 431 publications

References 13 publications

Glyphosate bioavailability in soil

Glyphosate bioavailability in soil

Glyphosate and phosphorus leaching and residues in boreal sandy soil

Effect of Glyphosate on Growth of Four Freshwater Species of Phytoplankton: A Microplate Bioassay

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