Transformation of chlorinated aliphatic compounds by ferruginous smectite.

Redox properties of structural Fe in clay minerals. 2. Electrochemical and spectroscopic characterization of electron transfer irreversibility in ferruginous smectite, SWa-1.

Structural Fe in clay minerals is an important, albeit poorly characterized, redox-active phase found in many natural and engineered environments. This work develops an experimental approach to directly assess the redox properties of a natural Fe-bearing smectite (ferruginous smectite, SWa-1, 12.6 wt % Fe) with mediated electrochemical reduction (MER) and oxidation (MEO). By utilizing a suite o...

Biodegradability of chlorinated solvents and related chlorinated aliphatic compounds

Effects of electron acceptors and donors on transformation of tetrachloromethane by Shewanella putrefaciens MR-1.

Transformation of chlorinated aliphatic compounds was examined in Shewanella putrefaciens strain MR-1, an obligately respiring facultative anaerobe. Under anaerobic conditions, MR-1 has been shown to transform tetrachloromethane to trichloromethane (24%), CO2 (7%), cell-bound material (50%) and unidentified nonvolatile products (4%). The highest rate and extent of transformation were observed w...

Alteration of mammalian-cell toxicity of pesticides by structural iron(II) in ferruginous smectite.

The ultimate concern over pesticides in the environment is their toxic impact on nontarget organisms, including humans. Soil clays are known to interact with pesticides in ways that decrease the concentration of the parent compound in the soil solution (adsorption, sequestration, degradation). These phenomena are generally regarded as beneficial, but toxicological verification is lacking. In th...

Transformations of halogenated organic compounds under denitrification conditions.

Trihalomethanes, carbon tetrachloride, 1,1,1-trichloroethane, 1,2-dibromoethane, chlorinated benzenes, ethylbenzene, and naphthalene at concentrations commonly found in surface and groundwater were incubated under anoxic conditions to study their transformability in the presence of denitrifying bacteria. None of the aromatic compounds showed significant utilization relative to sterile controls ...