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Title: Factors limiting sulfolane biodegradation in contaminated subarctic aquifer substrate
Argument: Sulfolane is a manmade compound used in petroleum refining. As such, it has no natural metabolic pathway to mineralization known yet. It is also very water soluble so should it spill, it is very likely to create plumes in groundwater. Sulfolane is of interest to the Fairbanks area since we have one such plume originating at the north pole refinery. Several microbiologists are examining sulfolane plumes and growing enrichment cultures from them, hoping to find an organism that has developed a metabolic pathway capable of degrading sulfolane. This is one such paper.
Citation:
Kasanke CP, Leigh MB (2017) Factors limiting sulfolane biodegradation in contaminated subarctic aquifer substrate. PLoS ONE 12(7): e0181462. https://doi.org/10.1371/journal. pone.0181462
Abstract:
Sulfolane, a water-soluble organosulfur compound, is used industrially worldwide and is associated with one of the largest contaminated groundwater plumes in the state of Alaska. Despite being widely used, little is understood about the degradation of sulfolane in the envi- ronment, especially in cold regions. We conducted aerobic and anaerobic microcosm stud- ies to assess the biological and abiotic sulfolane degradation potential of contaminated subarctic aquifer groundwater and sediment from Interior Alaska. We also investigated the impacts of nutrient limitations and hydrocarbon co-contamination on sulfolane degradation. We found that sulfolane underwent biodegradation aerobically but not anaerobically under nitrate, sulfate, or iron-reducing conditions. No abiotic degradation activity was detectable under either oxic or anoxic conditions. Nutrient addition stimulated sulfolane biodegradation in sediment slurries at high sulfolane concentrations (100 mg L-1), but not at low sulfolane concentrations (500 μg L-1), and nutrient amendments were necessary to stimulate sulfo- lane biodegradation in incubations containing groundwater only. Hydrocarbon co-contami- nation retarded aerobic sulfolane biodegradation rates by ~30%. Our study is the first to investigate the sulfolane biodegradation potential of subarctic aquifer substrate and identi- fies several important factors limiting biodegradation rates. We concluded that oxygen is an important factor limiting natural attenuation of this sulfolane plume, and that nutrient amend- ments are unlikely to accelerate biodegradation within in the plume, although they may bios- timulate degradation in ex situ groundwater treatment applications. Future work should be directed at elucidating the identity of indigenous sulfolane-degrading microorganisms and determining their distribution and potential activity in the environment.
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