Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have been recognized as one of the biggest public health issues of the 21 st century. Both ARB and ARGs have been determined in water after tr...Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have been recognized as one of the biggest public health issues of the 21 st century. Both ARB and ARGs have been determined in water after treatment with conventional disinfectants. Ultraviolet (UV) technology has been seen growth in application to disinfect the water. However, UV method alone is not adequate to degrade ARGs in water. Researchers are investigating the combination of UV with other oxidants (chlorine, hydrogen peroxide (H2O2), peroxymonosulfate (PMS), and photocatalysts) to harness the high reactivity of produced reactive species (C1-, C1O -, Cl2-,-OH, and SO4-_) in such processes with constituents of cell (e.g., deoxyribonucleic acid (DNA) and its components) in order to increase the degradation efficiency of ARGs. This paper briefly reviews the current status of different UV-based treatments (UV/chlorination, UV/H2O2, UV/PMS, and UV-photocatalysis) to degrade ARGs and to control horizontal gene transfer (HGT) in water. The review also provides discussion on the mechanism of degradation of ARGs and application of q-PCR and gel electrophoresis to obtain insights of the fate of ARGs during UV-based treatment processes.展开更多
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 ...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 k J/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.展开更多
文摘Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have been recognized as one of the biggest public health issues of the 21 st century. Both ARB and ARGs have been determined in water after treatment with conventional disinfectants. Ultraviolet (UV) technology has been seen growth in application to disinfect the water. However, UV method alone is not adequate to degrade ARGs in water. Researchers are investigating the combination of UV with other oxidants (chlorine, hydrogen peroxide (H2O2), peroxymonosulfate (PMS), and photocatalysts) to harness the high reactivity of produced reactive species (C1-, C1O -, Cl2-,-OH, and SO4-_) in such processes with constituents of cell (e.g., deoxyribonucleic acid (DNA) and its components) in order to increase the degradation efficiency of ARGs. This paper briefly reviews the current status of different UV-based treatments (UV/chlorination, UV/H2O2, UV/PMS, and UV-photocatalysis) to degrade ARGs and to control horizontal gene transfer (HGT) in water. The review also provides discussion on the mechanism of degradation of ARGs and application of q-PCR and gel electrophoresis to obtain insights of the fate of ARGs during UV-based treatment processes.
基金funding through NIEHS SRP(Superfund Hazardous Substance Research and Training Program),P42 ES0277704,and USDA Hatch 6215。
文摘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 k J/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.
