Decreased bioavailability of aminomethylphosphonic acid (AMPA) in genetically modified corn with activated carbon or calcium montmorillonite clay inclusion in soil

Abstract

The widespread use of pesticides has resulted in detectable residues throughout the environment, sometimes at concentrations well above regulatory limits. Therefore, the development of safe, effective, field-practical, and economically feasible strategies to mitigate the effects of pesticides is warranted. Glyphosate is an organophosphorus herbicide that is degraded to aminomethylphosphonic acid (AMPA), a toxic and persistent metabolite that can accumulate in soil and sediment and translocate to plants. In this study, we investigated the binding efficacy of activated carbon (AC) and calcium montmorillonite (CM) clay to decrease AMPA bioavailability from soil and AMPA translocation to plants. Adsorption isotherms and thermodynamic studies on AC and CM were conducted and showed tight binding (enthalpy values >−20 kJ/mol) for AMPA with high capacities (0.25 mol/kg and 0.38 mol/kg, respectively), based on derivations from the Langmuir model. A hydra assay was utilized to indicate toxicity of AMPA and the inclusion of 1% AC and CM both resulted in 90% protection of the hydra (**p ≤ 0.01). Further studies in glyphosate-contaminated soil showed that AC and CM significantly reduced AMPA bioavailability by 53% and 44%, respectively. Results in genetically modified (GM) corn showed a conversion of glyphosate to AMPA in roots and sprouts over a 10-day exposure duration. Inclusion of AC and CM reduced AMPA residues in roots and sprouts by 47%-61%. These studies collectively indicate that AC and CM are effective sorbents for AMPA and could be used to reduce AMPA bioavailability from soil and AMPA residues in GM corn plants.

L-Tryptophan Aqueous Systems at Low Concentrations: Interconnection between Self-Organization, Fluorescent and Physicochemical Properties, and Action on Hydrobionts

“…A convenient method for assessing BACs’ bioeffects in the range of low concentrations is to study the effects of their solutions on the growth and development of hydrobionts [ 18 , 19 , 20 , 21 ]. Ecotoxicological tests are currently becoming more and more in demand as they are closely related to the pressing issue of aquatic ecosystem protection [ 22 , 23 , 24 , 25 , 26 , 27 ].…”

Combining Experimental Isotherms, Minimalistic Simulations, and a Model to Understand and Predict Chemical Adsorption onto Montmorillonite Clays

“…Previously, montmorillonite clays have been shown to be safe for human − and animal consumption based on numerous animal models and human intervention studies in Africa and the United States. The efficient adsorption of CM for multiple environmental contaminant chemicals has been reported, including mycotoxins, pesticides, and PCBs. ,,,,− To further investigate the adsorption efficacy of CM for more chemicals (plasticizers, PAHs, industrial solvents, and pesticides), in this study, isothermal analyses were conducted and calculated using Freundlich or Langmuir models based on the correlation coefficient. The plots of adsorption isotherms of chlorpyrifos, phenol, and naphthalene onto CM surfaces fit the Langmuir model as indicated by the correlation coefficients ( r 2 > 0.85) and curved shapes, indicating the presence of saturable sites.…”

“… a K d and Δ G values are derived and reported in this study. Other values were extracted from previous experimental studies (refs , , , and − . …”

Inclusion of Montmorillonite Clays in Environmental Barrier Formulations to Reduce Skin Exposure to Water-Soluble Chemicals from Polluted Water

“…These materials have been researched extensively as active ingredients in sunscreen and should require no further safety evaluations. , In our study, carbon- and clay-based adsorbents have been incorporated in this formulation for their protection against UV radiation ranging from 250 to 400 nm, and more importantly, to prevent the incursion of hazardous environmental pollutants from water. Montmorillonites, with high surface area, neutral color, tunable pore size, and biocompatibility, have been shown to adsorb environmental chemicals efficiently and have been included in EVBs for environmental decontamination. − …”