| Title | Photodegradation of nitrite in lake waters: role of dissolved organic matter |
| Abstract | Here we studied the degradation rate of nitrite (NO-2), added to lake water at sub-micromolar levels, upon ultraviolet (UV) irradiation. NO-2 photodegradation was considerably faster in lake water compared with ultra-pure water. A key issue was the presence in lake water of hydroxyl radical (OH) scavengers that inhibited the reaction between NO-2 and OH. Such a reaction, while causing additional NO-2 transformation, produced nitrogen dioxide (NO-2) that was subsequently involved into the regeneration of NO-2 by dimerisation or the reaction with nitric oxide (NO). The scavenging of OH by compounds different from NO-2 (mainly dissolved organic matter, DOM) prevented the regeneration reactions from taking place, and enhanced the phototransformation of NO-2. Model calculations for the direct photolysis of NO-2, applied to the lake water samples, yielded a NO-2 half-life time of around three weeks in the mixing layer of the lakes because of photodegradation. Therefore, we conclude that photodegradation is a potentially important process to control the concentration of NO-2 in shallow lakes, or in deeper ones under stratification conditions. |
| Source | Environmental chemistry (Collingwood, Vic. Print) 5, pp. 407–415 |
| Keywords | dissolved organic matterenvironmental photochemistryhydroxyl radical scavengingnitrite photodegradationnitrogen geochemistry |
| Journal | Environmental chemistry (Collingwood, Vic. Print) |
| Editor | CSIRO Publishing, Collingwood, Vic., Australia |
| Year | 2009 |
| Type | Articolo in rivista |
| DOI | 10.1071/EN09050 |
| Authors | Vione D. (1), Minella M. (1), Minero C. (1), Maurino V. (1), Picco P. (1), Marchetto A., Tartari G. |
| Text | 53135 2009 10.1071/EN09050 ISI Web of Science WOS 000271005600006 dissolved organic matter environmental photochemistry hydroxyl radical scavenging nitrite photodegradation nitrogen geochemistry Photodegradation of nitrite in lake waters role of dissolved organic matter Vione D. 1 , Minella M. 1 , Minero C. 1 , Maurino V. 1 , Picco P. 1 , Marchetto A., Tartari G. 1 Dipartimento di Chimica Analitica, Universita di Torino, 10125 Torino, Italy. Here we studied the degradation rate of nitrite NO 2 , added to lake water at sub micromolar levels, upon ultraviolet UV irradiation. NO 2 photodegradation was considerably faster in lake water compared with ultra pure water. A key issue was the presence in lake water of hydroxyl radical OH scavengers that inhibited the reaction between NO 2 and OH. Such a reaction, while causing additional NO 2 transformation, produced nitrogen dioxide NO 2 that was subsequently involved into the regeneration of NO 2 by dimerisation or the reaction with nitric oxide NO . The scavenging of OH by compounds different from NO 2 mainly dissolved organic matter, DOM prevented the regeneration reactions from taking place, and enhanced the phototransformation of NO 2. Model calculations for the direct photolysis of NO 2, applied to the lake water samples, yielded a NO 2 half life time of around three weeks in the mixing layer of the lakes because of photodegradation. Therefore, we conclude that photodegradation is a potentially important process to control the concentration of NO 2 in shallow lakes, or in deeper ones under stratification conditions. 5 http //www.publish.csiro.au/journals/env articolo pubblicato 08_EnvChem_2009.pdf Articolo in rivista CSIRO Publishing 1448 2517 Environmental chemistry Collingwood, Vic. Print Environmental chemistry Collingwood, Vic. Print Environmental chemistry. Collingwood, Vic. Print aldo.marchetto MARCHETTO ALDO gabriele.tartari TARTARI GABRIELE TA.P04.016.004 Ecologia teorica e applicata degli ecosistemi acquatici |
