Effects of methyl-CD and humic acid on hydrolytic degradation of the herbicide diclofop-methyl.
Hydrolytic degradation of the herbicide diclofop-methyl was investigated in the multi-pH deionized water, natural aquatic systems and soil suspensions. Resulting data indicated that the herbicide was stable in the acidic and nearly neutral solutions for at least 15 d. The herbicide diclofop-methyl rapidly dissipated in the natural aquatic systems and soil suspensions with half-lives less than 4 d. Methyl-CD (partially methylated beta-cyclodextrin) improved its hydrolytic degradation in the pH 8 deionized water and natural aquatic systems while humic acid inhibited its hydrolytic degradation at the same conditions. But dissolved organic matter in the natural aquatic systems and soil suspensions increased its hydrolysis. Two catalysis mechanisms were introduced to describe the effects of cyclodextrin and organic matter on its hydrolytic metabolism. Though inorganic ions maybe improved its hydrolysis reaction in the natural aquatic systems, Fe2+ and Cu2+ did not form complexes with the herbicide and had poor influences on its hydrolytic degradation whether cyclodextrin was added or not.
Cai
Xi-yun
XY
Institute of Environment Science, Zhejiang University, Hangzhou 310029, China.
Wen
Yue-zhong
YZ
Zhong
Tian-xiang
TX
Liu
Wei-ping
WP
D002851:Chromatography, High Pressure Liquid; D003300:Copper / Q000737:chemistry; D003505:Cyclodextrins / Q000494:pharmacology*; D005618:Fresh Water / Q000737:chemistry; D055768:Halogenated Diphenyl Ethers; D006540:Herbicides / Q000737:chemistry*; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis / Q000187:drug effects; D007501:Iron / Q000737:chemistry; D007700:Kinetics; D010647:Phenyl Ethers / Q000737:chemistry*; D012987:Soil / Q000032:analysis
D003505:Cyclodextrins; D055768:Halogenated Diphenyl Ethers; D006540:Herbicides; D006812:Humic Substances; D010647:Phenyl Ethers; D012987:Soil; D003300:Copper; C012891:dichlorfop-methyl; D007501:Iron