A model assessment of the importance of direct photolysis in the photo-fate of cephalosporins in surface waters: Possible formation of toxic intermediates.
A model assessment of the importance of direct photolysis in the photo-fate of cephalosporins in surface waters: Possible formation of toxic intermediates.
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DOI：
10.1016/j.chemosphere.2015.04.102
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发表时间：
2015-09
期刊：
影响因子：
8.8
通讯作者：
D. Fabbri;M. Minella;V. Maurino;C. Minero;D. Vione
中科院分区：
文献类型：
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作者：
D. Fabbri;M. Minella;V. Maurino;C. Minero;D. Vione
根据光化学反应的文献值，用光化学模型预测了6种头孢菌素的直接和间接光降解。环境光降解在深度为⩽2-3米的表层水体和/或溶解有机碳值较低的较深水域(DOC、⩽和1 mg/C、L−1)中将是重要的。夏季的半衰期从几天到几周不等。在更深和更高DOC的水域和/或在不同季节，水解可能会压倒光降解。头孢菌素的直接光解对环境有影响，因为它会产生有毒的中间体。这将是头孢唑林的主要途径，也是阿莫西林和头孢噻肟的重要途径，在pH值为6.5的情况下，头孢匹林也是如此。相比之下，头孢拉定和头孢氨苄的直接光解作用可以忽略不计。DOC值会对浅水中直接光解所占的光解比例产生不同程度的影响，这取决于发色溶解有机物的三重态敏化作用的不同。
The direct and indirect photodegradation of six cephalosporins was predicted using a photochemical model, on the basis of literature values of photochemical reactivity. Environmental photodegradation would be important in surface water bodies with depth ⩽2–3 m, and/or in deeper waters with low values of the dissolved organic carbon (DOC ⩽ 1 mg C L−1). The half-life times would range from a few days to a couple of weeks in summertime. In deeper and higher-DOC waters and/or in different seasons, hydrolysis could prevail over photodegradation. The direct photolysis of cephalosporins is environmentally concerning because it is known to produce toxic intermediates. It would be a major pathway for cefazolin, an important one for amoxicillin and cefotaxime and, at pH < 6.5, for cefapirin as well. In contrast, direct photolysis would be negligible for cefradine and cefalexin. The DOC values would influence the fraction of photodegradation accounted for by direct photolysis in shallow water, to a different extent depending on the role of sensitisation by the triplet states of chromophoric dissolved organic matter.