Enhanced anaerobic biotransformation of carbon tetrachloride in the presence of reduced iron oxides

Journal Article · Fri Oct 01 04:00:00 EDT 1999 · Environmental Toxicology and Chemistry

DOI:https://doi.org/10.1897/1551-5028(1999)018<2142:EABOCT>2.3.CO;2· OSTI ID:20006589

Kim, S; Picardal, F W

Rates of anaerobic transformation of carbon tetrachloride (CT) by the facultative anaerobe Shewanella putrefaciens 200 were increased by the presence of Fe(III)-containing minerals. In batch reactors with amorphous, Fe(III)-hydroxide and S. putrefaciens, CT transformation rates could be modeled by a first-order expression in which the pseudo-first-order rate constant was linearly proportional to the initial concentration of Fe(III)-oxide. Subsequent measurement of soluble and acid-extractable FE(II) showed that increased CT transformation rates were proportional to microbially reduced, surface-bound Fe(II), rather than soluble Fe(II). In biomimetic experiments using 20 mM dithiothreitol (DTT) as a reductant, rates of transformation of CT by DTT were low in the absence of Fe(III)-oxides. However, in the presence of iron oxides, DTT was able to transform CT at elevated rates. Results again strongly suggested that surface-bound Fe(II) was primarily responsible for the reductive transformation of CT. Results suggested that the surface area of the iron mineral determines the rate of CT transformation by affecting the extent of iron reduction. Chloroform (CF) was the only transformation product identified and production of CF was nonstoichiometric. In microbial and abiotic experiments with Fe(III) oxides, the percentage of the transformed CT recovered as CF decreased even though the rate and extent of CT transformation was increased. Overall, their results have important implications for an improved understanding of possible microbial and geochemical interactions in the environmental transformation of chlorinated organic pollutants and for modeling of CT transformation rates in anaerobic, iron-bearing sediments.

• Research Organization: Indiana Univ., Bloomington, IN (US)
• OSTI ID: 20006589
• Journal Information: Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 10 Vol. 18; ISSN 0730-7268; ISSN ETOCDK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ANAEROBIC CONDITIONS
BACTERIA
BIODEGRADATION
CARBON TETRACHLORIDE
IRON OXIDES
REMEDIAL ACTION