Sunlight Photolysis of Safener Benoxacor and Herbicide Metolachlor as Mixtures on Simulated Soil Surfaces

2019 ◽  
Vol 53 (12) ◽  
pp. 6784-6793 ◽  
Author(s):  
Lei Su ◽  
Leandra M. Caywood ◽  
John D. Sivey ◽  
Ning Dai
Keyword(s):  
Herbicide Metolachlor

scholarly journals Kinetics and thermodynamics of the hydroxylation products in the photodegradation of the herbicide Metolachlor

2020 ◽  
Vol 92 (3) ◽  
pp. 473-484
Author(s):  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Oscar N. Ventura
Keyword(s):  
Aqueous Solution ◽  
Gas Phase ◽  
Density Functional ◽  
Electronic Structure Calculations ◽  
Kinetic Characteristics ◽  
Kinetics And Thermodynamics ◽  
Composite Methods ◽  
Herbicide Metolachlor ◽  
Kinetics Of ◽  
Structure Calculations

AbstractElectronic structure calculations have been performed to determine the thermochemistry and kinetics of the reaction between OH and the radicals of the S enantiomer of the herbicide Metolachlor, 2-chloro-N-(2-methyl-6-ethylphenyl)-N(2-methoxy-1-methylethyl) acetamide (MC), produced by photoinduced breaking of the C–Cl bond. Both density functional and ab initio composite methods were employed to calculate the structure of reactants, intermediates, transition states and products, in gas phase and in aqueous solution. The expected relative abundance of each product was calculated and compared to the experimentally observed concentrations. It is shown that a combination of thermodynamic and kinetic characteristics interplay to produce the expected theoretical abundances, which turn out to be in agreement with the experimentally observed distribution of products.

Biochar characteristics produced from rice husks and their sorption properties for the acetanilide herbicide metolachlor

2016 ◽  
Vol 24 (5) ◽  
pp. 4552-4561 ◽  
Author(s):  
Lan Wei ◽  
Yufen Huang ◽  
Yanliang Li ◽  
Lianxi Huang ◽  
Nyo Nyo Mar ◽  
...  
Keyword(s):  
Sorption Properties ◽  
Rice Husks ◽  
Herbicide Metolachlor

scholarly journals Impact of Soil Aeration on the Environmental Fate of Pre-Emergent Herbicide Metolachlor

2021 ◽  
Vol 11 (18) ◽  
pp. 8567
Author(s):  
Ramdas Kanissery ◽  
Wenwen Liu ◽  
Ruby Tiwari ◽  
Gerald Sims
Keyword(s):  
Weed Management ◽  
Environmental Fate ◽  
Field Application ◽  
Anaerobic Conditions ◽  
Soil Microcosms ◽  
Soil Redox ◽  
Herbicide Metolachlor ◽  
Adsorption Desorption ◽  
The Impact ◽  
Kinetics Of

The impact of the aeration status of soils on the environmental fate of the soil-applied pre-emergent herbicide metolachlor is of significance to sustainable agriculture practices and has not been investigated thoroughly by existing research works. To address this knowledge gap, we examined the adsorption, desorption, degradation, and mineralization of radioactively labeled [14C] metolachlor in Catlin, Flanagan, and Drummer soils under aerobic and anaerobic conditions. Based on our findings, anaerobic conditions in the soil significantly reduced the adsorption of 14C-metolachlor while also promoting its desorption, thereby potentially releasing a greater amount of herbicide from the soil after a field application. The first-order degradation and mineralization kinetics of 14C-metolachlor were distinctively enhanced by anaerobic conditions in all the soils tested. Furthermore, the degradation and mineralization rates of 14C-metolachlor in non-sterilized versus sterilized soil microcosms clearly indicated microbial activity in the degradation of metolachlor in soil. The results from this study suggest that soil redox conditions could impact the bioavailability and environmental fate of herbicide metolachlor and should be taken into consideration as part of sustainable weed management programs.

Influence of Chemical Treatments on Glutathione S-Transferases of Maize with Activity Towards Metolachlor and Cinnamic Acid

1998 ◽  
Vol 53 (11-12) ◽  
pp. 973-979 ◽  
Author(s):  
Charles K. Cottingham ◽  
Kriton K. Hatzios ◽  
Sue Meredith
Keyword(s):  
Cinnamic Acid ◽  
Zea Mays L ◽  
Glutathione S Transferase ◽  
Chemical Treatments ◽  
Etiolated Seedlings ◽  
Glutathione S Transferases ◽  
Membrane Bound ◽  
Herbicide Metolachlor ◽  
Triton X ◽  
Gst Activity

Abstract The subcellular distribution of glutathione S-transferase (GST) activity extracted from shoots of 3-day-old etiolated seedlings of maize (Zea mays L., Northrup-K ing 9283 hybrid) and the induction of soluble and m em brane-bound G ST activity by the safener benoxacor, the herbicide metolachlor and their com bination (CGA -180937) were investigated. GST activity extracted from maize shoots was detected in both cytosolic and microsomal fractions and utilized l-chloro-2,4-dinitrobenzene (CDNB ), metolachlor, and trans-cinnamic acid (CA) as substrates. Soluble GST activity extracted from maize shoots was greater than m icrosom al with CDNB or metolachlor as substrate. Membrane-bound GT activity was greater than soluble with cinnamic acid as substrate. W ashing the microsomal preparations from maize shoots with Triton X-100 increased GST (C A ) activity. Pretreatment with the safener benoxacor or a form ulated combination of the herbicide metolachlor with benoxacor induced soluble GST(CDNB ), GST(metolachlor) and GST (C A ) activities in m aize shoots. Benoxacor and CGA-180937 induced also membrane-bound GST (CDNB ) and GST(CA ) activities in maize shoots, but did not affect membrane-bound GST (metolachlor) activity. These results confirm that maize contains multiple GST isozymes that differ in their subsrate specificity and inducibility by safeners or other chemicals.

Toxic effects of Atrazine, Deethyl-Atrazine, Deisopropyl-Atrazine and Metolachlor on Chlorella fusca var fusca

2013 ◽  
Vol 1 (1) ◽  
pp. 39-46
Keyword(s):  
Growth Rates ◽  
Degradation Products ◽  
Toxic Effects ◽  
Chlorella Fusca ◽  
Cell Numbers ◽  
Bioassay System ◽  
Herbicide Atrazine ◽  
Herbicide Metolachlor ◽  
Reduced Toxicity ◽  
Toxic Concentrations

The toxic effects of the herbicide Atrazine, its degradation products deethyl-atrazine and deisopropylatrazine, and the herbicide metolachlor were examined in unialgal cultures of Chlorella fusca var-fusca. The toxicity of a mixture of atrazine and metolachlor was also evaluated using the same bioassay system. Cell numbers were determined daily and growth rates were calculated for a period of 4 days. The order of toxicity of chemicals was atrazine>metolachlor>deethyl-atrazine>deisopropyl-atrazine. The presence of a mixture of atrazine and metolachlor in toxic concentrations lower than the EC50 resulted in reduced toxicity (antagonism) in comparison with the toxicity caused by the sum of toxic actions of the same levels of concentration from single chemicals.

Enantioselective Toxicity of Chiral Herbicide Metolachlor toMicrocystis aeruginosa

2019 ◽  
Vol 67 (6) ◽  
pp. 1631-1637 ◽  
Author(s):  
Siyu Chen ◽  
Lijuan Zhang ◽  
Hui Chen ◽  
Zunwei Chen ◽  
Yuezhong Wen
Keyword(s):  
Herbicide Metolachlor

Toxicity of the Herbicide Metolachlor, some Transformation Products and a Commercial Safener to an Alga (Selenastrum capricornutum), a Cyanophyte (Anabaena cylindrica) and a Macrophyte (Lemna gibba)

1996 ◽  
Vol 31 (1) ◽  
pp. 197-214 ◽  
Author(s):  
K.E. Day ◽  
V. Hodge
Keyword(s):  
Green Alga ◽  
Parent Compound ◽  
Dry Weight ◽  
Transformation Products ◽  
Selenastrum Capricornutum ◽  
Toxicity Tests ◽  
Cell Biomass ◽  
Inhibition Of Growth ◽  
Quality Guideline ◽  
Herbicide Metolachlor

Abstract The toxicity of the herbicide metolachlor, three photodegradation products (CGA-40172, CGA-40919, CGA-37735), two metabolic products (CGA-50720, CGA-51202) and a commercial safener (benoxacor) was determined in plant toxicity tests. The species tested were the green alga, S. capricornutum, the blue-green cyanophyte, A. cylindrica, and duckweed, L. gibba. The endpoint measured for all three species was inhibition of growth determined as a decrease in cell biomass for the algae or a decrease in frond production and dry weight in duckweed. S. capricornutum was the most sensitive species to the parent compound (72-h IC50’s ranged from 37.2-55.8 µg/L) followed by L. gibba (7-day IC50’S ranged from 304-788 µg/L for decreased frond production or 766 µg/L for a decrease in dry weight). The blue-green alga, A. cylindrica, was not affected by any of the compounds tested at concentrations as high as 4.0 mg/L. None of the transformation products was toxic at concentrations up to 10 mg/L. The safener decreased growth of S. capricornutum at concentrations ranging from 1,730-2,050 µg/L (72-h IC50’s). It is recommended that the interim Canadian water quality guideline of 8 µg/L be reexamined in light of these and other data.

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