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<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.

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

FABBRI, DEBORA;MINELLA, Marco;MAURINO, Valter;MINERO, Claudio;VIONE, Davide Vittorio
2015

Abstract

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<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.
134
452
458
http://www.sciencedirect.com/science/article/pii/S0045653515004713
Cephalosporins; Direct photolysis; Emerging pollutants; Environmental photochemistry; Environmental Chemistry; Chemistry (all)
Fabbri, Debora; Minella, Marco; Maurino, Valter; Minero, Claudio; Vione, Davide
File in questo prodotto:
File Dimensione Formato  
Chemosphere_2015_134_452–458.pdf

Accesso riservato

Descrizione: Articolo principale
Tipo di file: PDF EDITORIALE
Dimensione 3.55 MB
Formato Adobe PDF
3.55 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Chemo2015_cephalosporins_my.pdf

Accesso aperto con embargo fino al 20/01/2018

Tipo di file: POSTPRINT (VERSIONE FINALE DELL’AUTORE)
Dimensione 6.52 MB
Formato Adobe PDF
6.52 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1542797
Citazioni
  • ???jsp.display-item.citation.pmc??? 0
  • Scopus 19
  • ???jsp.display-item.citation.isi??? 20
social impact