Identification and ecotoxicity of degradation products of chloroacetamide herbicides from UV-treatment of water

Kinetics and Thermodynamics of the Hydroxylation Products in the Photodegradation of the Herbicide Metolachlor

“…Only the most stable isomers of MC and MCRads, obtained in our previous study [34], were used in this work. It is generally admitted that the photo oxidation of MC under environmental conditions starts with Cl elimination by photocatalytic cleavage of the C-Cl bond, leading to the formation of MCrad [26,27,29,30]. We calculated the binding energy of the C-Cl bond as 74.1 kcal mol -1 at the M06/6-31+G(d,p) level of theory in our former work [34].…”

“…Non-biological photodecomposition and oxidation of MC, on the other side, lead to many species which have been also identified in surface waters [5][6][7][8][9][10][11][12][13][14][15][16]. Given its possible high environmental impact due to its extended use, numerous experimental studies have been performed on the photocatalytic oxidation under diverse environmental conditions, examining the nature and toxicity of the photoproducts [17,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. It is well established that sunlight irradiation causes the cleavage of the C-Cl bond.…”

Structural elucidation of metolachlor photoproducts by liquid chromatography/high-resolution tandem mass spectrometry

“…Only some monohydroxylated compounds could be identified by GC/MS in a previous work. [19] The combined use of CID experiments and labeled compounds allowed the identification of new cyclic structures. The oral rat LD50 predicted values for these compounds exhibit a greater toxicity than that estimated for metolachlor, according to the results obtained with standard ecotoxicity assays.…”

“…This is of great concern considering that some of them were evaluated to be significantly more toxic than metolachlor. [19] With the aim of covering a larger range of polarities, the chemical structures of some degradation products of chloroacetamides were investigated using both GC/MS/MS and LC/MS/MS except for metolachlor for which only TPs characterized by GC/MS/MS have been reported. [19] Gutowski and coworkers [20] have recently compared TPs formed by photolysis of s-metolachlor and its commercial product Mercantor Gold.…”

Chemical Waste and Allied Products

“…Herbicides and biodegradation products were extracted from MBR effluent using solid-phase extraction followed by detection using high-performance liquid chromatography coupled with mass spectrometry (Ghoshdastidar and Tong, 2013). Souissi et al, (2013) Jilani, S (2013) reported that bacterial isolate, Pseudomonas, designated as IES-Ps-1, was used to assess its potential for pesticide removal from industrial wastewater using the biosimulator (activated sludge process). The findings indicated that Pseudomonas (IES-Ps-1) strain can be used for the treatment of the pesticide contaminated environment.…”