论文成果
More toxic and photoresistant products from photodegradation of fenoxaprop-p-ethyl
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- 论文类型：期刊论文
- 发表时间：2008-09-10
- 发表刊物：JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
- 收录刊物：PubMed、SCIE、Scopus
- 文献类型：J
- 卷号：56
- 期号：17
- 页面范围：8226-8230
- ISSN号：0021-8561
- 关键字：fenoxaprop-p-ethyl; photolysis products; acute toxicity; Daphnia magna
- 摘要：The photodegradation pathway of the commonly used herbicide fenoxaprop-p-ethyl (FE) was elucidated, and the effects of the photodegradation on its toxicity evolution were investigated. Under solar irradiation, FE could undergo photodegradation, and acetone enhanced the photolysis rates significantly. The same photoproducts formed under the irradiation of lambda > 200 nm and lambda > 290 nm through rearrangement, loss of ethanol after rearrangement, de-esterification, dechlorination, photohydrolysis, and the breakdown of the ether linkages. One of the main transformation products, 4-[(6-chloro-2-benzoxazolyl)oxy] phenol (CBOP), was resistant to photodegradation under the irradiation of lambda > 290 nm, and its photolysis rate was seven times slower than the parent under the irradiation of lambda > 200 nm. Among the metabolites, CBOP (48 h EC50 of 1.49-1.64 mg/L) and hydroquinone (48 h EC50 of 0.25-0.28 mg/L) were more toxic to Daphnia magna than the parent FE (48 h EC50 of 4.2-6.9 mg/L). Thus, more toxic and photoresistant products were generated from photolysis of the herbicide. Ecotoxicological effects of phototransformed products from pesticides should be emphasized for the ecological risk assessment of these anthropogenic pollutants.
