Mecoprop mineralization potential at oxygen-reduced conditions in subsoil with phenoxy acid contamination history

作者：Frkova Zuzana; Johansen Anders^*; Karlson Ulrich Gosewinkel

来源：Soil Biology and Biochemistry, 2015, 84: 189-198.

DOI：10.1016/j.soilbio.2015.02.004

• Mecoprop
• Soil microorganisms
• Biodegradation
• Nitrate-reducing conditions
• Natural attenuation

Historic phenoxy acid waste disposal and spillage at an industrial site close to Copenhagen (Denmark) has contaminated the groundwater with especially mecoprop (RS)-2-(4-chloro-2-methylphenoxy)propionic acid. The contamination is very persistent, probably because it is situated in the subsoil where biological degradation of the contaminant is hindered by lack of oxygen or alternative electron acceptors like nitrate. To examine this, we sampled soil at 3, 4.5 and 6 m depth at the contaminated site and measured the microbial mineralization of mecoprop as affected by nitrate and glucose at nitrate-reducing conditions. The results showed that at these conditions, glucose always had a clear negative impact on mecoprop mineralization. Mineralization of mecoprop was significantly enhanced in soil inoculated with phenoxy acid degraders (p<0.001), in comparison to the non-inoculated controls. After a lag-phase of similar to 7 weeks, up to 50% of initially added mecoprop was mineralized. However, the genomic DNA band pattern of numerically dominant isolates at the end of the experiment did not match with the inoculated strains. A mineralization assay confirmed that mecoprop was degraded by an indigenous microbial consortium. The findings in this study suggest that stimulation of indigenous microbes is a promising approach for removing persistent mecoprop contamination in subsoils.

• 出版日期2015-5