Title: Photochemical behavior of alloxydim herbicide in environmental waters. Structural elucidation and toxicity of degradation products

Abstract: The photochemical degradation of the herbicide alloxydim has been investigated in different aqueous media such as ground, river, mineral and ultrapure water under natural and simulated solar irradiation. The study revealed that alloxydim half-lives depend on the composition of the water and the radiation source. The photodegradation of alloxydim gives rise to the formation of two degradation products. The major degradation product, isolated and concentrated by SPE, was characterized by 1H NMR, 13C NMR, COSY, HMQC and HMBC techniques. This by-product corresponds to the reduction of the oxime moiety with the subsequent formation of the imine group and is a mixture of two tautomers where each molecule presents a keto–enol tautomerism. In addition, the toxicity of irradiated solutions was evaluated by means of a bioassay following the standard microtest procedure based on the decrease of light emission by the marine bacterium Vibrio fischeri. The results indicated that the toxicity of the photoproducts was higher than the toxicity of the parent compound. [Sandín-España, P., Sevilla-Morán,B., Calvo, L., Mateo-Miranda, M. & Alonso-Prados, J. (2012). Photochemical behavior of alloxydim herbicide in environmental waters. Structural elucidation and toxicity of degradation products. Microchemical Journal. doi.org/10.1016/j.microc.2012.07.003]. ${imageDescription} Comment

Keywords: Photodegradation; Alloxydim; NMR; Environmental waters; Toxicity

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Article: WeedsNews3824 (permalink)
Categories: :WeedsNews:health, :WeedsNews:herbicides, :WeedsNews:research alert, :WeedsNews:ecology, :WeedsNews:rivers, :WeedsNews:pollution
Date: 4 October 2012; 5:05:46 PM AEST

Author Name: Zheljana Peric
Author ID: zper12