The paper deals with the aqueous environmental fate of N,N-diethyl-m-toluamide (DEET), one of the most widespread and efficient mosquito repellents. The investigation involved monitoring of the DEET decomposition and the identification of intermediate compounds. Initially, control experiments in the dark and under illumination were performed on sterilized and river water spiked with DEET, with the aim to simulate all possible transformation processes occurring in aquatic system. Under illumination, DEET was degraded and transformed into numerous organic intermediate compounds, 37 of which could be identified. Several isomeric species were formed and characterized by analysing MS and MSn spectra, and by comparison with parent molecule fragmentation pathways. These laboratory simulation experiments were verified in the field to check the mechanism previously supposed. River water was sampled and analysed at eight sampling points. Among the transformation products (TPs) identified in river water spiked with DEET, twelve of them were also found in natural river water. The transformation occurring in aquatic systems involved dealkylation, mono- and poly-hydroxylation followed by oxidation of the hydroxyl groups and cleavage of the alkyl chains. Two TPs were principally formed in dark condition, while the others are mainly produced through indirect photolysis processes mediated by natural photosensitizers.
N,N-diethyl-m-toluamide transformation in river water
CALZA, Paola;MEDANA, Claudio;GIANCOTTI, Valeria Rachele;MINERO, Claudio
2011-01-01
Abstract
The paper deals with the aqueous environmental fate of N,N-diethyl-m-toluamide (DEET), one of the most widespread and efficient mosquito repellents. The investigation involved monitoring of the DEET decomposition and the identification of intermediate compounds. Initially, control experiments in the dark and under illumination were performed on sterilized and river water spiked with DEET, with the aim to simulate all possible transformation processes occurring in aquatic system. Under illumination, DEET was degraded and transformed into numerous organic intermediate compounds, 37 of which could be identified. Several isomeric species were formed and characterized by analysing MS and MSn spectra, and by comparison with parent molecule fragmentation pathways. These laboratory simulation experiments were verified in the field to check the mechanism previously supposed. River water was sampled and analysed at eight sampling points. Among the transformation products (TPs) identified in river water spiked with DEET, twelve of them were also found in natural river water. The transformation occurring in aquatic systems involved dealkylation, mono- and poly-hydroxylation followed by oxidation of the hydroxyl groups and cleavage of the alkyl chains. Two TPs were principally formed in dark condition, while the others are mainly produced through indirect photolysis processes mediated by natural photosensitizers.File | Dimensione | Formato | |
---|---|---|---|
OP_51.pdf
Accesso aperto
Tipo di file:
POSTPRINT (VERSIONE FINALE DELL’AUTORE)
Dimensione
670.46 kB
Formato
Adobe PDF
|
670.46 kB | Adobe PDF | Visualizza/Apri |
deet_2011_scitot.pdf
Accesso riservato
Tipo di file:
PDF EDITORIALE
Dimensione
3.47 MB
Formato
Adobe PDF
|
3.47 MB | Adobe PDF | Visualizza/Apri Richiedi una copia |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.