Coupling between Pentachlorophenol Dechlorination and Soil Redox As Revealed by Stable Carbon Isotope, Microbial Community Structure, and Biogeochemical Data

Abstract

Carbon isotopic analysis and molecular-based methods were used in conjunction with geochemical data sets to assess the dechlorination of pentachlorophenol (PCP) when coupled to biogeochemical processes in a mangrove soil having no prior history of anthropogenic contamination. The PCP underwent 96% dechlorination in soil amended with acetate, compared to 21% dehalogenation in control soil. Carbon isotope analysis of residual PCP demonstrated an obvious enrichment of 13C (εC, -3.01±0.1%). Molecular and statistical analyses demonstrated that PCP dechlorination and Fe(III) reduction were synergistically combined electron-accepting processes. Microbial community analysis further suggested that enhanced dechlorination of PCP during Fe(III) reduction was mediated by members of the multifunctional family of Geobacteraceae. In contrast, PCP significantly suppressed the growth of SO4(2-) reducers, which, in turn, facilitated the production of CH4 by diversion of electrons from SO4(2-) reduction to methanogenesis. The integrated data regarding stoichiometric alterations in this study gives direct evidence showing PCP, Fe(III), and SO4(2-) reduction, and CH4 production are coupled microbial processes during changes in soil redox.

Improved rhizoremediation for decabromodiphenyl ether (BDE-209) in E-waste contaminated soils

“…The recoveries of BDE-209 was 93.4±1.68%. Soil dissolved organic carbon (DOC) and dissolved total nitrogen (DTN) were extracted with Milli-Q water, and the supernatant was measured using an automated total organic carbon analyzer (Multi N/C 3100, Analytik Jena AG, Jena, Germany) (Xu et al, 2015;Dai et al, 2016). The NH 4 + and NO 3 concentrations were measured using a continuous flow analyzer (TRAACS 2000, Bran and Luebbe, Norderstedt, Germany) after soil samples were extracted with 1 mol$L -1 KCl (Zhou et al, 2014).…”

“…and Fe 3+ as electron acceptors participating in the microbial dehalogenated respiration (Kotik et al, 2013;Xu et al, 2014Xu et al, , 2015. He et al (2015) found that both NO 3 and Fe 3+…”

Application of stable isotopes to examine N proportions within a simulatedAegiceras corniculatumwetland

“…Stable C isotopic composition, C:N and other indicators have been applied in food web studies of mangrove ecosystems, including biogeochemical cycles (such as belowground ecosystem C cycling), and other ecological processes, as well as the paleoenvironmental reconstruction, sea level rise, paleoclimate change, paleosalinity, and other study topics [12][13][14][15][16][17][18][19][20][21]. The use of δ 13 C can reflect the long-term integrated physiological processes in plants, and has a certain degree of correlation with salinity; therefore the plant δ 13 C can be seen as a characteristic indicator of physiological responses in the presence of changes in environmental factors [22].…”

Shifts in indigenous microbial communities during the anaerobic degradation of pentachlorophenol in upland and paddy soils from southern China

“…The Fe(III) reducing bacteria Clostridium was also observed in the anaerobic enrichment with PCP degradation (Xu et al, 2015). Members of this genus were able to degrade PCP via pH modification by Fe(III) compounds or increase the degradation rate of PCP by generating sorbed Fe(II) (Xu et al, 2015). In this study, considering the high concentration of Fe 2 O 3 in both soils (Table 1), it is assumed that Fe(III)-reducing bacteria Clostridium might be involved in PCP degradation.…”

“…S4 in SI). The Fe(III) reducing bacteria Clostridium was also observed in the anaerobic enrichment with PCP degradation (Xu et al, 2015). Members of this genus were able to degrade PCP via pH modification by Fe(III) compounds or increase the degradation rate of PCP by generating sorbed Fe(II) (Xu et al, 2015).…”