title: Widespread Distribution of Dehalococcoides mccartyi in the Houston Ship Channel and Galveston Bay, Texas, Sediments and the Potential for Reductive Dechlorination of PCDD/F in an Estuarine Environment.
abstract: Sediments in the Houston Ship Channel and upper Galveston Bay, Texas, USA, are polluted with polychlorinated dibenzo-p-dioxins/furans (PCDD/F; ≤46,000 ng/kg dry weight (wt.)) with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener, contributing >50 % of the total toxic equivalents (TEQ) at most locations. We measured PCDD/F concentrations in sediments and evaluated the potential for enhanced in situ biodegradation by surveying for Dehalococcoides mccartyi, an obligate organohalide respiring bacterium. Dehalococcoides spp. (98 % similar to D. mccartyi) and 22 other members of the class Dehalococcoidia were predominant 16S ribosomal RNA (rRNA) phylotypes. Dehalococcoides spp. were also present in the active fraction of the bacterial community. Presence/absence PCR screening detected D. mccartyi in sediment cores and sediment grab samples having at least 1 ng/kg dry wt. TEQ at salinities ranging from 0.6 to 19.5 PSU, indicating that they are widespread in the estuarine environment. Organic carbon-only and organic carbon + sulfate-amended sediment microcosm experiments resulted in ∼60 % reduction of ambient 2,3,7,8-TCDD in just 24 months leading to reductions in total TEQs by 38.4 and 45.0 %, respectively, indicating that 2,3,7,8-TCDD degradation is occurring at appreciable rates.
authors.affiliation: Department of Oceanography, Texas A&M University, 3146 TAMU, College Station, TX, 77843, USA. charlotte_hieke@tamu.edu.|Department of Poultry Science, Texas A&M University, 2472 TAMU, College Station, TX, 77843, USA. charlotte_hieke@tamu.edu.
authors.forename: Anne-Sophie Charlotte
authors.initials: AC
authors.lastname: Hieke
authors.affiliation: Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA.
authors.forename: Robin
authors.initials: R
authors.lastname: Brinkmeyer
authors.affiliation: Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA.|Department of Earth and Environmental Sciences, University of Kentucky, 101 Slone Research Building, Lexington, KY, 40506, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Yeager
authors.affiliation: Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA.|Department of Earth and Environmental Sciences, University of Kentucky, 101 Slone Research Building, Lexington, KY, 40506, USA.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Schindler
authors.affiliation: Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA.
authors.forename: Saijin
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA.
authors.forename: Chen
authors.initials: C
authors.lastname: Xu
authors.affiliation: Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Louchouarn
authors.affiliation: Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Santschi
mesh_terms: D061006:Bays / Q000382:microbiology*; D001572:Benzofurans / Q000378:metabolism*; D001673:Biodegradation, Environmental; D041862:Chloroflexi / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D063366:Estuaries; D019015:Geologic Sediments / Q000382:microbiology*; D059013:Microbial Consortia / Q000502:physiology; D010084:Oxidation-Reduction; D010802:Phylogeny; D000072317:Polychlorinated Dibenzodioxins / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013781:Texas; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D001572:Benzofurans; D000072317:Polychlorinated Dibenzodioxins; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical
keywords: Bioremediation; Dehalococcoides mccartyi; Dioxins; Estuary; Galveston Bay; Houston Ship Channel