Impacts of microbial redox conditions on the phase distribution of pyrene in soil–water systems

• Published in: Environmental pollution (1987) 2008-03, Vol.152 (1), p.106-115
• Main Authors: Kim, Han S., Roper, J. Chadwick, Pfaender, Frederic K.
• Format: Article
• Language: English
• Subjects: aerobic conditions; Aerobiosis; anaerobic conditions; Anaerobiosis; Applied sciences; Aromatics; Biodegradation, Environmental; Biological and physicochemical properties of pollutants. Interaction in the soil; Diagenesis; dissolved organic matter; Earth sciences; Earth, ocean, space; Ecology; Engineering and environment geology. Geothermics; Environmental Monitoring - methods; Exact sciences and technology; Humic Substances; humification; Hydrophobic organic contaminant; Organic matter; Oxidation-Reduction; Particle Size; polluted soils; Pollution; Pollution, environment geology; pyrene (hydrocarbon); Pyrenes - analysis; Pyrenes - chemistry; Redox condition; redox reactions; sediment contamination; Soil - analysis; Soil and sediments pollution; Soil Microbiology; soil microorganisms; soil organic matter; Soil Pollutants - analysis; Soil Pollutants - chemistry; soil pollution; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - chemistry
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2007.05.018

Variations in the soil/sediment organic matter (SOM)-hydrophobic organic contaminant (HOC) bindings upon microbially mediated redox conditions were examined. While the extractability of pyrene associated with soil declined after its biodegradation began during aerobic incubation, its variations were almost constant (±3.0–4.4%) during anoxic/anaerobic incubations. The dissolved organic matter released from the soil incubated under highly reduced conditions became more humified and aromatic, had a higher average molecular weight, and was more polydispersed compared to that obtained from oxic incubation, similar to the SOM alterations in the early stage of diagenesis (humification). The concentrations of pyrene in the aqueous phase increased significantly during the soil incubations under highly reduced conditions due to its favorable interaction with the altered DOM. Our results suggest that the microbially mediated redox conditions have significant impacts on SOM and should be considered for the transport, fate, bioavailability, and exposure risk of HOCs in the geo-environments. HOC association within soil/sediment matrix can be controlled by microbially mediated redox conditions.