Biological and abiotic dechlorination of highly chlorinated dioxins in biphasic microcosms
- Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Civil and Environmental Engineering
A novel experimental approach to help increase the rates and extent of reductive dechlorination of polychlorinated dibenzo-p-dioxins (PCDD) is presented. Biphasic microcosms emulsions containing eluted microorganisms derived from historically contaminated Passaic River (New Jersey) sediments, and 4% (v/v) of decane, were spiked with mg/L of octaCDD. The microcosms were amended separately with three polyphenolic compounds--catechol, resorcinol, and 3,4-dihydroxybenzoate--to help improve electron transfer during reductive dechlorination. Abiotic controls containing phenolic compounds only, and pasteurized cells were monitored along with the active microcosms. Lesser-chlorinated congeners were observed in all treatments, including killed cells, indicating the potential not only for biological and abiotic, but also biogenic dechlorination mechanisms. After 3 months of incubation, tetraCDD isomers were produced in biological incubations only, and up to 30% of the spiked octaCDD was removed. Polyphenolic compounds first appear to transiently complex with the dioxins prior to further dechlorination, and did not increase the dechlorination rates over unamended cells. Whereas the 2,3,7,8-/1,4,6,9-substitution ratio of heptachlorinated congeners increased in all treatments, 2,3,7,8-substituted hexaCDDs congeners were identified mainly in active cell incubations. Further isomer-specific analysis may thus enable distinction between abiotic and biotic dechlorination processes in anaerobic sediments.
- OSTI ID:
- 490972
- Report Number(s):
- CONF-950483-; ISBN 1-57477-008-X; TRN: IM9729%%223
- Resource Relation:
- Conference: 3. international in situ and on-site bioreclamation symposium, San Diego, CA (United States), 24-27 Apr 1995; Other Information: PBD: 1995; Related Information: Is Part Of Bioremediation of recalcitrant organics; Hinchee, R.E.; Anderson, D.B. [eds.] [Battelle Memorial Inst., Columbus, OH (United States)]; Hoeppel, R.E. [ed.] [Naval Facilities Engineering Services Center, Port Hueneme, CA (United States)]; PB: 378 p.; Bioremediation, Volume 3(7)
- Country of Publication:
- United States
- Language:
- English
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