title: Role of Fe(III), phosphate, dissolved organic matter, and nitrate during the photodegradation of domoic acid in the marine environment.
abstract: The photodegradation of domoic acid in model seawater containing varying amounts of total Fe(lll) (expressed as Fe(lll)), NO(3-), total phosphate (expressed as P04(3-)), and dissolved organic matter (DOM) is reported. A multivariate, microscale, high-throughput experimental approach is described for evaluating how these components interact to control the removal of domoic acid from natural waters. Under the nominal conditions of the study ([Fe(lll)]o 0-4 microM; [N03-]o 0-35 microM; [P04(3-)]o 0-4 microM; [DOM]o 0-10 mg/ L), it is apparent that Fe(lll) and DOM are significant promoters of domoic acid photooxidation. In contrast, P04(3-) interacts with Fe(lll) to inhibit the photooxidation of domoic acid, but P04(3-) alone does not act to slow or accelerate domoic acid photodegradation. No other variables (singly or interactively) have a statistically significant impact. At an incident light intensity of 765 W/m2 and initial domoic acid concentration of 0.96 microM, domoic acid half-lives range over 12-36 h, with half-life a function of [Fe(III)], [PO4(3-)], and dissolved organic matter loadings. An NMR based technique for measuring domoic acid-Fe(lll) binding (1.72 x 10(11)) is reported.
authors.affiliation: Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.
authors.forename: Justina M
authors.initials: JM
authors.lastname: Fisher
authors.forename: James G
authors.initials: JG
authors.lastname: Reese
authors.forename: Perry J
authors.initials: PJ
authors.lastname: Pellechia
authors.forename: Peter L
authors.initials: PL
authors.lastname: Moeller
authors.forename: John L
authors.initials: JL
authors.lastname: Ferry
mesh_terms: D007501:Iron / Q000737:chemistry*; D007608:Kainic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015999:Multivariate Analysis; D009566:Nitrates / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D012623:Seawater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009566:Nitrates; D010710:Phosphates; D014874:Water Pollutants, Chemical; D007501:Iron; C012301:domoic acid; D007608:Kainic Acid