title: Biostimulation and bioaugmentation to enhance dechlorination of polychlorinated dibenzo-p-dioxins in contaminated sediments.
abstract: Dechlorination of spiked 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TeCDD) was investigated in sediment microcosms from three polychlorinated dibenzo-p-dioxin and dibenzofuran (CDD/F)-contaminated sites: River Kymijoki, Finland; Gulf Island Pond, Maine; and Lake Roosevelt, Washington. Dechlorination was stimulated by addition of electron donor and halogenated priming compounds, and bioaugmentation by a mixed culture containing Dehalococcoides ethenogenes strain 195. Amendment with 1,2,3,4-tetrachlorobenzene (1,2,3,4-TeCB) promoted rapid dechlorination of 1,2,3,4-TeCDD to 2-monochlorodibenzo-p-dioxin (2MCDD) in Gulf Island Pond and River Kymijoki sediments, however, only slow dechlorination to 1,4-dichlorodibenzo-p-dioxin was observed in Lake Roosevelt sediments. The dechlorination pathway in 1,2,3,4-TeCB-amended microcosms proceeded mainly via 1,3-dichlorodibenzo-p-dioxin, with less production of 2,3-dichlorodibenzo-p-dioxin in comparison with other treatments. Microbial community analyses indicated that Dehalococcoides-like bacteria were enriched with 1,2,3,4-TeCB. Quantitative real-time PCR analysis of Dehalococcoides-specific 16S rRNA genes and the D. ethenogenes strain 195 dehalogenase gene, tceA, showed at least an order of magnitude higher gene copy numbers in the bioaugmented than in the nonbioaugmented microcosms. An active-dechlorinating population is present in the River Kymijoki and biostimulation may enhance both native Dehalococcoides spp. and the bioaugmented D. ethenogenes strain 195.
authors.affiliation: Department of Biochemistry and Microbiology and Biotechnology Center for Agriculture and the Environment, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA.
authors.forename: Young-Beom
authors.initials: YB
authors.lastname: Ahn
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Donna E
authors.initials: DE
authors.lastname: Fennell
authors.forename: Max M
authors.initials: MM
authors.lastname: Häggblom
mesh_terms: D001572:Benzofurans / Q000378:metabolism*; D041862:Chloroflexi / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D017753:Ecosystem; D004586:Electrophoresis / Q000379:methods; D005387:Finland; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology*; D008281:Maine; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000235:genetics; D000072317:Polychlorinated Dibenzodioxins / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012989:Soil Pollutants / Q000378:metabolism*; D014861:Washington
chemical_list: D001572:Benzofurans; D000072317:Polychlorinated Dibenzodioxins; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; C023614:dibenzofuran; D010088:Oxidoreductases