Sorption-desorption of 2,4-dichlorophenoxyacetic acid by wetland sediments

Gaultier, Jeanette; Farenhorst, Annemieke; Kim, Sung Min; Saiyed, Ibrahim M.; Messing, Paul G.; Cessna, Allan J.; Glozier, Nancy E.

doi:10.1672/08-42.1

Cited by 11 publications

(5 citation statements)

References 34 publications

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“…No loss was observed in the filtered controls or unfiltered lake water incubations over 28−140 days (Figures 3b and S6). Because 2,4-D has a high solubility (0.1 M) 34,55,84 and a low carbon−water partitioning coefficient (K oc ) of 61.7−78 mL g −1 (Table S11), 42,85 we concluded that loss in the microcosms was due to biodegradation by microbes in the sediment. This observation is consistent with previous reports of 2,4-D 55 and other polar organic compound 5 degradation in water/sediment systems.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Synthesizing Laboratory and Field Experiments to Quantify Dominant Transformation Mechanisms of 2,4-Dichlorophenoxyacetic Acid (2,4-D) in Aquatic Environments

White

Nault

McMahon

et al. 2022

Environ. Sci. Technol.

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Laboratory studies used to assess the environmental fate of organic chemicals such as pesticides fail to replicate environmental conditions, resulting in large errors in predicted transformation rates. We combine laboratory and field data to identify the dominant loss processes of the herbicide 2,4dichlorophenoxyacetic acid (2,4-D) in lakes for the first time. Microbial and photochemical degradation are individually assessed using laboratory-based microcosms and irradiation studies, respectively. Field campaigns are conducted in six lakes to quantify 2,4-D loss following large-scale herbicide treatments. Irradiation studies show that 2,4-D undergoes direct photodegradation, but modeling efforts demonstrated that this process is negligible under environmental conditions. Microcosms constructed using field inocula show that sediment microbial communities are responsible for degradation of 2,4-D in lakes. Attempts to quantify transformation products are unsuccessful in both laboratory and field studies, suggesting that their persistence is not a major concern. The synthesis of laboratory and field experiments is used to demonstrate best practices in designing laboratory persistence studies and in using those results to mechanistically predict contaminant fate in complex aquatic environments.

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Section: ■ Materials and Methodsmentioning

confidence: 99%

Synthesizing Laboratory and Field Experiments to Quantify Dominant Transformation Mechanisms of 2,4-Dichlorophenoxyacetic Acid (2,4-D) in Aquatic Environments

White

Nault

McMahon

et al. 2022

Environ. Sci. Technol.

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“…To our knowledge, there have been no studies on the effect of temperature on glyphosate sorption. Studies using other herbicides have found that 2,4-D sorption decreases (Aksu and Kabasakal, 2005;Gupta et al 2006) or increases (Gaultier et al, 2009) with increasing temperature. Regardless, the effect of temperature on sorption is small because, between 5 and 25 o C, the 2,4-D sorption distribution coefficient only varied by 1 to 3% (Gaultier et al, 2009).…”

Section: Sorption Studiesmentioning

confidence: 99%

Phosphate fertilizer impacts on glyphosate sorption by soil

et al. 2016

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“…Mathematical models that estimate pesticide fate in rivers commonly include a sorption parameter (e.g., Kd, Koc) because when a pesticide is sorbed by sediments, it has different degradation rate and transport potential than when the same pesticide is dissolved in the water column. There is substantial information available on pesticide sorption parameters as it relates to sediments (Chefetz et al 2004;Gaultier et al 2009;Dollinger et al 2015;Gamhewage et al 2019) but less so as it relates to other potential constituents present in rivers such as microplastics, ash, and charcoal.…”

Section: Introductionmentioning

confidence: 99%

Sorption of pesticides by microplastics, charcoal, ash, and river sediments

Fatema

Farenhorst

2022

J Soils Sediments

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Purpose In addition to sediments, pesticides can be sorbed to other constituents present in rivers including ash, charcoal, and microplastics. Pesticide sorption by microplastics has been studied for hydrophobic compounds such as the legacy insecticide DDT (dichlorodiphenyltrichloroethane) but not for current-use herbicides. The purpose of this study was to investigate to what extent 2,4-dichlorophenoxyacetic acid (2,4-D) (weak acid), atrazine (weak base), and glyphosate (zwitterion) are sorbed by microplastics (i.e., fiber, polyethylene beads, polyvinyl chloride (PVC), and tire fragments) and other river constituents (i.e., ash, charcoal, suspended and bottom sediments). DDT was included in the study to provide reference data that could be compared to known literature values. Methods Batch equilibrium experiments were conducted following Guidelines 106 of the Organisation for Economic Cooperation and Development. Experiments utilized either a 1:100 solid/solution ratio with 0.1 g of a river constituent as the sorbent or a 1:5 solid/solution ratio with the sorbents consisted of 1.9 g bottom sediments mixed with 0.1 g of a river constituent. Background solutions included 0.01 M CaCl 2 or 0.01 M KCl, deionized water, and river water. Result Individual microplastics always sorbed >50% of DDT. Current-use herbicides had a weak affinity for microplastics (< 6%) except that a substantial amount of glyphosate was sorbed by PVC (32-36%) in 0.01M KCl and DI water. When river water was used as a background solution, rather than 0.01M KCl or deionized water, there was much less glyphosate sorption by PVC, ash, charcoal, and both sediments. This suggested that ions present in river water competed for sorption sites with glyphosate molecules. Across background solutions, sorption by sediments decreased in the order of DDT (91-95%) > glyphosate (36-88%) >atrazine (5-13%) >2,4-D (2-5%). Sorption of 2,4-D, atrazine, and DDT by ash and charcoal was always > 90% but < 35% for glyphosate. Relative to bottom sediments alone, the presence of ash or charcoal (5% by weight) with sediments significantly increased the sorption of 2,4-D, atrazine, and DDT. Microplastic additions (5% by weight) had no impact on all four pesticides' sorption by sediments. Conclusion Microplastics are not a strong sorbent for current-use herbicides, although there are exceptions such as glyphosate by PVC. Ions present in river water competed with glyphosate for sorption sites of river constituents. Hence, the types and concentrations of ions present in rivers might have some influence on the partitioning of glyphosate between the water column and solid phase, including glyphosate fate processes in rivers.

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Sorption-desorption of 2,4-dichlorophenoxyacetic acid by wetland sediments

Cited by 11 publications

References 34 publications

Synthesizing Laboratory and Field Experiments to Quantify Dominant Transformation Mechanisms of 2,4-Dichlorophenoxyacetic Acid (2,4-D) in Aquatic Environments

Synthesizing Laboratory and Field Experiments to Quantify Dominant Transformation Mechanisms of 2,4-Dichlorophenoxyacetic Acid (2,4-D) in Aquatic Environments

Phosphate fertilizer impacts on glyphosate sorption by soil

Sorption of pesticides by microplastics, charcoal, ash, and river sediments

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