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Impacts of a surface washing agent and chemical herder on the aerobic biodegradation of crude oil
Citation:
Lech, K., R. Conmy, R. Grosser, D. Sundaravadivelu, AND L. Trutschel. Impacts of a surface washing agent and chemical herder on the aerobic biodegradation of crude oil. Presented at EPA International Decon Conference, Charleston, SC, December 05 - 07, 2023.
Impact/Purpose:
Laboratory findings presented here suggest that the chemical treating agents used in this study pose little risk to oil-degrading microbial communities in situ and potentially enrich for specific microbial groups that promote complete biodegradation (mineralization).
Description:
Oil spill chemical treating agents, such as dispersants, surface washing agents, and chemical herders, expand the range of response options available to decision-makers during oil spills. Due to the response actions and reliance on chemical dispersants during the Deepwater Horizon oil spill, the effects of dispersants on naturally-occuring oil biodegradation in marine environments have been heavily investigated and scrutinized. However, less is known about the fate of other chemical treating agents and effects on marine microbial communities, including those responsible for oil biodegradation. Using an active oil-degrading microbial consortium, we examined the impacts of a surface washing agent (CytoSol) and chemical herder (ThickSlick 6535) on the aerobic biodegradation of oil in laboratory incubations. We measured the transformation and mineralization of weathered crude oil and spill treating agents, changes in microbial biomass, and alterations of microbial community structure over a period of 48 days. The degradation of parent hydrocarbon compounds, specifically alkanes and polycyclic aromatic hydrocarbons (PAHs), was minimally impacted by the introduction of the two chemical treating agents. Microbial growth was enhanced by the addition of the chemical treating agents and distinct shifts in the microbial community were observed among treatments and over the duration of the study. Mineralization of the oil and treating agents occurred in all biologically active treatments including those containing treating agent alone (i.e. no oil or other carbon), signifying the oil-degrading microbial community can also readily degrade CytoSol and ThickSlick 6535. Higher levels of carbon dioxide were produced in treatments containing both oil and treating agent than the sum of the individual treatments. These laboratory findings suggest that the chemical treating agents used in this study pose little risk to oil-degrading microbial communities in situ and potentially enrich for specific microbial groups that promote complete biodegradation (mineralization). Disclaimer: The views expressed in this work are those of the authors and do not necessarily reflect the opinions or policies of the U.S. EPA. This publication does not constitute an endorsement of any commercial product.