Validation of an Integrative Methodology to Assess and Monitor Reductive Dechlorination of Chlorinated Ethenes in Contaminated Aquifers

0465214 - MBÚ 2017 RIV CH eng J - Článek v odborném periodiku
Tarnawski, S.E. - Rossi, P. - Brennerová, Mária - Stavělová, M. - Holliger, Ch.
Validation of an Integrative Methodology to Assess and Monitor Reductive Dechlorination of Chlorinated Ethenes in Contaminated Aquifers.
Frontiers in Environmental Science. Roč. 4, February (2016), s. 7. E-ISSN 2296-665X
Grant CEP: GA TA ČR TA02020534
Institucionální podpora: RVO:61388971
Klíčová slova: dechlorination * integrative methodology * chlorinated ethenes
Obor OECD: Microbiology

Bioremediation of tetra-and trichloroethene-contaminated aquifers is frequently hampered due to incomplete dechlorination to the more toxic dichloroethene (DCE) and vinyl chloride (VC), indicating insufficient knowledge about the biological mechanisms related to aquifer functioning. A methodology based on the joint analysis of geochemical and microbiological datasets was developed to assess the presence of the biochemical potential for complete reductive dechlorination to harmless ethene and to explain the reasons for which degradation often stalls at the more toxic intermediates. This methodology is composed of three successive steps, with (i) the acquisition of geochemical data including chlorinated ethenes (CEs), (ii) the detailed analysis of the bacterial community structures (BCS) as well as the biochemical potential for complete dechlorination using microcosms and molecular detection of organohalide-respiring bacteria and key reductive dehalogenases, and (iii) a statistical Multiple Factor Analysis (MFA) combining the above mentioned abiotic and biotic variables in a functional modeling of the contaminated aquifer. The methodology was validated by analyzing two chlorinated ethenes-contaminated sites. Results from the first site showed that the full biochemical potential for ethene production was present in situ. However, redox potential was overall too high and locally manganese reduction out-competed CEs reduction, explaining the reasons for the local accumulation of DCE and VC to a lesser extent. The second contaminated aquifer was under bioremediation by successive cheese whey injections. Analysis demonstrated that cheese whey additions led to increasingly reduced redox conditions and that hampered reductive dechlorination was not due to competition with other anaerobic respiration processes.
Trvalý link: http://hdl.handle.net/11104/0264320