FeSO{sub 4} amendments stimulate extensive anaerobic PCB dechlorination
- Michigan State Univ., East Lansing, MI (United States). Dept. of Crop and Soil Sciences
Anaerobic microbial reductive dechlorination of PCBs is important because it removes the chlorine substituents that block aerobic metabolism and it reduces PCB toxicity. Although this process occurs widely in nature, its extent is often limited to dechlorination of some of the chlorines in the meta positions of biphenyl. In this report the authors demonstrate the ability to achieve nearly complete meta plus para dechlorination of Aroclor 1242. This involves the additions of FeSO{sub 4} to PCB contaminated sediments and results in {approximately}90 mol % of the total PCBs being converted to aerobically degradable ortho-substituted mono- and dichlorinated congeners. They propose that iron sulfate provides two mutually beneficial effects leading to its stimulation of anaerobic PCB dechlorination. Sulfate stimulates growth of sulfate reducing organisms responsible for PCB dechlorination, while Fe{sup 2+} reduces sulfide bioavailability and hence toxicity by forming the insoluble precipitate FeS. Ferrous sulfate is an inexpensive, innocuous compound which could be utilized to overcome factors limiting both the extent of in situ dechlorination as well as the implementation of sequential anaerobic/aerobic biotreatment systems. In addition it is expected that the toxicities of Aroclors, and hence the risk they pose, will be substantially reduced at sites where PCBs have been extensively dechlorinated.
- OSTI ID:
- 323753
- Journal Information:
- Environmental Science and Technology, Journal Name: Environmental Science and Technology Journal Issue: 21 Vol. 32; ISSN ESTHAG; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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