title: Dioxin photoproducts of triclosan and its chlorinated derivatives in sediment cores.
abstract: Triclosan, a widely used antimicrobial, is known to undergo phototransformation in aqueous solution to form 2,8-dichlorodibenzo-p-dioxin (2,8-DCDD). Two sediment cores from a wastewater-impacted depositional zone of the Mississippi River were analyzed for triclosan by ultra performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS-Q(3)) and for a suite of polychlorinated dioxins and furans by high resolution gas chromatography-mass spectrometry (HRGC-MS) to provide evidence of this photoreaction in the environment. 2,8-DCDD was detected at levels that trended with the historical use of triclosan since its introduction in the 1960s. Three other dioxin congeners, 2,3,7-TCDD, 1,2,8-TriCDD, and 1,2,3,8-TCDD, which are known photoproducts of chlorinated derivatives of triclosan, were also detected with similar trend profiles. These four congeners comprised the majority of di- through tetra-chlorinated dioxins. The trend profile of these specific dioxin congeners did not correlate with the trend profile of the higher-chlorinated dioxin homologues or any chlorinated furan homologues, suggesting a unique source. These results are fully consistent with the phototransformation of triclosan and its chlorinated derivatives that form during wastewater chlorine disinfection as the source of 2,8-DCDD, 2,3,7-TriCDD, 1,2,8-TriCDD, and 1,2,3,8-TCDD in this aquatic environment. As the levels of triclosan-derived dioxins increased over time and the total level of chlorinated dioxins decreased, the contribution of triclosan-derived dioxins to the total dioxin pool increased to as high as 31% by mass in recent years, indicating that their contribution to total dioxin toxicity may need consideration.
authors.affiliation: Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, USA.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Buth
authors.forename: Peter O
authors.initials: PO
authors.lastname: Steen
authors.forename: Charles
authors.initials: C
authors.lastname: Sueper
authors.forename: Dylan
authors.initials: D
authors.lastname: Blumentritt
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Vikesland
authors.forename: William A
authors.initials: WA
authors.lastname: Arnold
authors.forename: Kristopher
authors.initials: K
authors.lastname: McNeill
mesh_terms: D004147:Dioxins / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry*; D054879:Halogenation; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*; D008027:Light; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives / Q000737:chemistry; D013997:Time Factors; D014260:Triclosan / Q000737:chemistry*
chemical_list: D004147:Dioxins; D006843:Hydrocarbons, Chlorinated; D000072317:Polychlorinated Dibenzodioxins; D014260:Triclosan