Samples were taken from sediment of the River Spittelwasser (district Bitterfeld, Germany), which is highly polluted with PCDD/Fs and other chloroorganic compounds. The sediment cores were separated into 10-20 cm thick layers, spiked with 50 microM of 1,2,3,4-tetrachlorodibenzo-p-dioxin and incubated for 8 months under anaerobic conditions in the presence of cosubstrates. Reductive dechlorinati...

The dechlorination of chlorinated hydrocarbons has been examined in detail. The reaction is catalyzed by cytochrome P-450 and occurs optimally in the presence of oxygen although some dechlorination may occur under anaerobic conditions. Halothane has been shown to undergo an oxidative dechlorination and a reductive defluorination. Enzymatic attack of chlorinated olefins and hydrocarbons is not o...

In this paper we describe the sequence of reactions leading from tetrachloro-para-hydroquinone to 1,2,4-trihydroxybenzene by inducible enzymes of Rhodococcus chlorophenolicus. Tetrachlorohydroquinone was first converted to a dichlorotrihydroxybenzene in a reaction involving both hydrolytic and reductive dechlorination; no trichlorinated intermediate was detected. Dichlorotrihydroxybenzene was s...

Clayey tills contaminated with chlorinated solvents are a threat to groundwater and are difficult to remediate. A numerical model is developed for assessing leaching processes and for simulating the remediation via enhanced anaerobic dechlorination. The model simulates the transport of a contaminant in a single fracture-clay matrix system coupled with a reactive model for anaerobic dechlorinati...

BACKGROUND Microbial reductive dechlorination of polychlorinated biphenyls (PCBs) plays a major role in detoxifying anoxic contaminated freshwater and marine sediments from PCBs. Known members of the phylum Chloroflexi are typically responsible for this activity in freshwater sediments, whereas less is known about the microorganisms responsible for this activity in marine sediments. PCB-respiri...

In this study, bimetallic Pd/Fe(0) particles were synthesized and employed to reduce chloroform in aqueous solution. The investigation emphasized on the effects of some key reaction parameters including Pd/Fe(0) dosage, pH, oxidation-reduction potential (ORP) and presence of anions on the reductive dechlorination reaction. The experimental results showed that high Pd/Fe(0) dosage, low initial p...

INTRODUCTION Chlorinated ethanes and ethenes are among the most frequently detected organic pollutants of water. Their physicochemical properties are such that they can contaminate aquifers for decades. In favourable conditions, they can undergo degradation. In anaerobic conditions, chlorinated solvents can undergo reductive dechlorination. DEGRADATION PATHWAYS Abiotic dechlorination is usual...

In this study, the effects of initial bacterial load (102 , 104 and 106 cells/ml) dechlorination idiosyncrasy on efficacy varying concentrations (0.018–0.126% v/v applied for 30 minutes) a point-of-use chlorine-based proprietary disinfectant (WaterCare®) were investigated in drinking water. Results indicated that higher cell populations significantly affected disinfectant.Subsequent disinfected...

The present study has investigated a correlation between the kinetics of polychlorinated biphenyl (PCB) dechlorination and the growth of dechlorinating microbial populations. Microorganisms were eluted from Aroclor 1248-contaminated St. Lawrence River (NY, USA) sediments and inoculated into clean sediments spiked with Aroclor 1248 at 10 concentrations ranging from 0 to 3.12 micromol/g sediment ...

Two highly enriched cultures containing Dehalococcoides spp. were used to study the effect of aceticlastic methanogens on reductive vinyl chloride (VC) dechlorination. In terms of aceticlastic methanogens, one culture was dominated by Methanosaeta, while the other culture was dominated by Methanosarcina, as determined by fluorescence in situ hybridization. Cultures amended with 2-bromoethanesul...