Degradation and enantiomeric fractionation of mecoprop in soil previously exposed to phenoxy acid herbicides - New insights for bioremediation

0465236 - BC 2017 RIV NL eng J - Journal Article
Frková, Zuzana - Johansen, A. - de Jonge, L.W. - Olsen, P. - Gosewinkel, U. - Bester, K.
Degradation and enantiomeric fractionation of mecoprop in soil previously exposed to phenoxy acid herbicides - New insights for bioremediation.
Science of the Total Environment. Roč. 569, November (2016), s. 1457-1465. ISSN 0048-9697. E-ISSN 1879-1026
Institutional support: RVO:60077344
Keywords : phenoxy acids * nitrate-reducing conditions * herbicide biodegradation * enantioselectivity * biostimulation
Subject RIV: DK - Soil Contamination ; De-contamination incl. Pesticides
Impact factor: 4.900, year: 2016

Phenoxy acid-contaminated subsoils are common as a result of irregular disposal of residues and production wastes in the past. For enhancing in situ biodegradation at reducing conditions, biostimulation may be an effective option. Some phenoxy acids were marketed in racemic mixtures, and biodegradation rates may differ between enantiomers. Therefore, enantio-preferred degradation of mecoprop (MCPP) in soil was measured to get in-depth information on whether amendment with glucose (BOD equivalents as substrate for microbial growth) and nitrate (redox equivalents for oxidation) can stimulate bioremediation. The degradation processes were studied in soil sampled at different depths (3, 4.5 and 6 m) at a Danish urban site with a history of phenoxy acid contamination. We observed preferential degradation of the R-enantiomer only under aerobic conditions in the soil samples from 3- and 6-m depth at environmentally relevant (nM) MCPP concentrations: enantiomer fraction (EF) < 0.5. On the other hand, we observed preferential degradation of the S-enantiomer in all samples and treatments at elevated (mu M) MCPP concentrations: EF > 0.5. Three different microbial communities were discriminated by enantioselective degradation of MCPP: 1) aerobic microorganisms with little enantioselectivity, 2) aerobic microorganisms with R-selectivity and 3) anaerobic denitrifying organisms with S-selectivity.
Permanent Link: http://hdl.handle.net/11104/0263890