title: Photolysis of 2,4,6-trinitrotoluene in seawater and estuary water: Impact of pH, temperature, salinity, and dissolved organic matter.
abstract: The influence of salinity, pH, temperature, and dissolved organic matter on the photolysis rate of 2,4,6-trinitrotoluene (TNT) in marine, estuary, and laboratory-prepared waters was studied using a Suntest CPS+® solar simulator equipped with optical filters. TNT degradation rates were determined using HPLC analysis, and products were identified using LC/MS. Minimal or no TNT photolysis occurred under a 395-nm long pass filter, but under a 295-nm filter, first-order TNT degradation rate constants and apparent quantum yields increased with increasing salinity in both natural and artificial seawater. TNT rate constants increased slightly with increasing temperature (10 to 32°C) but did not change significantly with pH (6.4 to 8.1). The addition of dissolved organic matter (up to 5mg/L) to ultrapure water, artificial seawater, and natural seawater increased the TNT photolysis rate constant. Products formed by TNT photolysis in natural seawater were determined to be 2,4,6-trinitrobenzaldehyde, 1,3,5-trinitrobenzene, 2,4,6-trinitrobenzoic acid, and 2-amino-4,6-dinitrobenzoic acid.
authors.affiliation: Chemistry Department, U.S. Naval Academy, 572 M Holloway Road, Annapolis, MD 21402, United States. Electronic address: prak@usna.edu.
authors.forename: Dianne J
authors.initials: DJ
authors.lastname: Luning Prak
authors.affiliation: Chemistry Department, U.S. Naval Academy, 572 M Holloway Road, Annapolis, MD 21402, United States. Electronic address: James.Breuer17@gmail.com.
authors.forename: James E T
authors.initials: JE
authors.lastname: Breuer
authors.affiliation: Chemistry Department, U.S. Naval Academy, 572 M Holloway Road, Annapolis, MD 21402, United States. Electronic address: earios0904@gmail.com.
authors.forename: Evelyn A
authors.initials: EA
authors.lastname: Rios
authors.affiliation: Chemistry Department, U.S. Naval Academy, 572 M Holloway Road, Annapolis, MD 21402, United States. Electronic address: e.jeds@yahoo.com.
authors.forename: Erin E
authors.initials: EE
authors.lastname: Jedlicka
authors.affiliation: Chemistry Department, U.S. Naval Academy, 572 M Holloway Road, Annapolis, MD 21402, United States. Electronic address: osulliva@usna.edu.
authors.forename: Daniel W
authors.initials: DW
authors.lastname: O'Sullivan
mesh_terms: D063366:Estuaries; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D009579:Nitrobenzoates; D010782:Photolysis; D054712:Salinity; D012623:Seawater / Q000737:chemistry*; D013472:Sunlight; D013696:Temperature; D014301:Trinitrobenzenes; D014303:Trinitrotoluene / Q000032:analysis / Q000737:chemistry*; D014867:Water; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D062367:ortho-Aminobenzoates
chemical_list: D006812:Humic Substances; D009579:Nitrobenzoates; D014301:Trinitrobenzenes; D014874:Water Pollutants, Chemical; D062367:ortho-Aminobenzoates; D014867:Water; D014303:Trinitrotoluene; C029222:sym-trinitrobenzene; C587445:2-amino-4,6-dinitrobenzoic acid
keywords: Explosives; Nitrogen compounds; Photochemistry; Ultraviolet radiation