title: Monitoring and evaluation of the environmental dissipation of the marine antifoulant 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) in a Danish Harbor.
abstract: The concentration of marine antifoulant 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT; the active ingredient in Sea-Nine 211 Antifouling Agent) leaching into a Danish Harbor from two painted ships was quantitated at varying distances from the ships. Sediment and suspended particulate matter were also analyzed for DCOIT. Water samples were concentrated on-site using C-18 solid phase extraction and subsequently analyzed by gas chromatography-tandem mass spectrometry. A strong decline in DCOIT water concentration as a function of distance from the ships was observed. The highest concentration (maximum 283 ng/l) was measured in the immediate vicinity of the ships and the concentration declined rapidly to less than the limit of detection (5 ng/l) at 400 m from the ships' surfaces. The measured decline curve was compared to that calculated using a one-dimensional model (ECoS). The comparison indicates that the primary mechanism of dissipation of DCOIT is not dilution resulting from dispersion but degradation with a rate constant in the order of 1 h(-1). Thus the field results correlate with the earlier microcosm studies demonstrating that DCOIT biodegrades rapidly in a marine environment.
authors.affiliation: Institute for Environmental Studies, Vrije Universiteit, De Boelelaan 1087, NL 1081 HV Amsterdam, The Netherlands.
authors.forename: Ruud J C A
authors.initials: RJ
authors.lastname: Steen
authors.forename: Freek
authors.initials: F
authors.lastname: Ariese
authors.forename: Bert
authors.initials: B
authors.lastname: van Hattum
authors.forename: Jens
authors.initials: J
authors.lastname: Jacobsen
authors.forename: Andrew
authors.initials: A
authors.lastname: Jacobson
mesh_terms: D001673:Biodegradation, Environmental; D003718:Denmark; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D008401:Gas Chromatography-Mass Spectrometry; D019015:Geologic Sediments / Q000032:analysis*; D008956:Models, Chemical; D012623:Seawater / Q000032:analysis*; D013844:Thiazoles / Q000737:chemistry*
chemical_list: D013844:Thiazoles; C080469:Kathon 930