A model assessment of the importance of direct photolysis in the photo-fate of cephalosporins in surface waters: Possible formation of toxic intermediates

[Display omitted] •Cephalosporins are transformed in surface waters by hydrolysis and photochemistry.•Photochemistry would prevail in waters with low depth and/or low DOC.•Important direct photolysis for cefazolin, negligible for cefradine and cefalexin.•Direct photolysis is favoured in shallow wate...

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Bibliographic Details
Published in:Chemosphere (Oxford) 2015-09, Vol.134, p.452-458
Main Authors: Fabbri, Debora, Minella, Marco, Maurino, Valter, Minero, Claudio, Vione, Davide
Format: Article
Language:English
Subjects:
Amoxicillin - chemistry
Carbon - chemistry
Cefazolin - chemistry
Cephalexin - chemistry
Cephalosporin
Cephalosporins
Cephalosporins - chemistry
Cephradine - chemistry
Direct photolysis
Emerging pollutants
Environmental photochemistry
Fresh Water - chemistry
Half-Life
Hydrogen-Ion Concentration
Hydrolysis
Mathematical models
Models, Chemical
Models, Theoretical
Photochemical
Photodegradation
Photolysis
Surface water
Toxic
Toxicology
Water Pollutants, Chemical - analysis
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Summary:[Display omitted] •Cephalosporins are transformed in surface waters by hydrolysis and photochemistry.•Photochemistry would prevail in waters with low depth and/or low DOC.•Important direct photolysis for cefazolin, negligible for cefradine and cefalexin.•Direct photolysis is favoured in shallow waters with intermediate/high DOC values.•Such conditions favour the formation of toxic intermediates. 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 ⩽2–3m, and/or in deeper waters with low values of the dissolved organic carbon (DOC⩽1mgCL−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
ISSN:0045-6535
1879-1298
DOI:10.1016/j.chemosphere.2015.04.102