The kinetics of polychlorinated biphenyl (PCB) dechlorination by Hudson River (New York, USA) sediment microorganisms were investigated using Aroclor 1242 at 10 concentrations ranging from 0 to 900 ppm (0-11.2 micromol Cl/g sediment). The time course of PCB dechlorination and population growth were determined by congener-specific analysis and the most-probable-number technique, respectively, ov...

We investigated whether the threshold concentration for polychlorinated biphenyl (PCB) dechlorination may be lower in biosurfactant-amended sediments compared with biosurfactant-free samples. At PCB concentrations of 40, 60, and 120 ppm, the surfactant amendment enhanced the PCB dechlorination rate at all concentrations and the rate was also faster at higher concentrations. On a congener group ...

Vitamin B(12), reduced by titanium (III) citrate to vitamin B(12s), catalyzes the reductive dechlorination of chlorophenols. Reductive dechlorination of pentachlorophenol and of all tetrachlorophenol and trichlorophenol isomers was observed. Reaction of various chlorophenols with vitamin B(12) favored reductive dechlorination at positions adjacent to another chlorinated carbon, but chlorines or...

This research was carried out to assess the dechlorination and decomposition of Polychlorinated biphenyls (PCBs) in the real waste transformer oil using polyethylene glycol 1000/NaOH through a modified household microwave oven. To do so, the influence of polyethylene glycol (PEG) (1.5-7.5 g) and NaOH (0.3-1.5 g) under microwave (MW) power of 500 W on the dechlorination efficiency of PCBs, exist...

Title of Document: THE ROLE OF DEHALORESPIRING BACTERIA IN THE REDUCTIVE DECHLORINATION OF POLYCHLORINATED BIPHENYLS IN BALTIMORE HARBOR SEDIMENT MICROCOSMS Sonja Kristine Fagervold, Doctor of Philosophy, 2007 Directed By: Professor Kevin R. Sowers, Marine Estuarine Environmental Sciences Baltimore Harbor sediment microcosms were incubated with the 12 most predominant congeners in Aroclor 1260 ...

The determination of compound-specific stable isotope ratios is a promising new tool to assess biodegradation of organic compounds in groundwater. In this study, the occurrence of carbon isotope fractionation during dechlorination of tetrachloroethene (PCE) to ethene was evaluated in a PCE-contaminated aquifer and in a microcosm that was based on aquifer material from the site. In the microcosm...

Microbial reductive dechlorination of the persistent polychlorinated biphenyls (PCBs) is attracting much attention in cleanup of the contaminated environment. Nevertheless, most PCB dechlorinating cultures require presence of sediment or sediment substitutes to maintain their dechlorination activities which hinders subsequent bacterial enrichment and isolation processes. The information on enri...

In situ treatment of PCB contaminated sediments via microbial dechlorination is a promising alternative to dredging, which may be reserved for only the most contaminated areas. Reductive dechlorination of low levels of weathered PCB mixtures typical of urban environments may occur at slow rates. Here, we report that biostimulation and bioaugmentation enhanced dechlorination of low concentration...

Residual petroleum hydrocarbons and polychlorinated biphenyls (PCBs) are frequently found together at contamination sites. Intrinsic reductive dechlorination of PCBs at these sites is highly variable. Sediments of Silver Lake (MA), which contain ∼6.2% petroleum hydrocarbons, did not support PCB dechlorination in laboratory assays. Removal of petroleum components from Silver Lake sediments by so...

When microorganisms eluted from upper Hudson River sediment were cultured without any substrate except polychlorobiphenyl (PCB)-free Hudson River sediment, methane formation was the terminal step of the anaerobic food chain. In sediments containing Aroclor 1242, addition of eubacterium-inhibiting antibiotics, which should have directly inhibited fermentative bacteria and thereby should have ind...