Oil spills, both large and small scale, are a significant concern for the environment due to the potential damage they can cause. While large oil spills receive substantial media attention, there are also numerous smaller spills that occur annually in lakes, rivers, and oceans. Research published in ACS’ Energy & Fuels has shown that the longer oil remains in freshwater environments, the more chemical changes it undergoes, resulting in products that can persist in the environment. Approximately 600,000 gallons of oil were accidentally spilled into the environment in 2023, including both ocean spills and freshwater spills. These spills can lead to various chemical transformations in the oil, making certain compounds more soluble in water and increasing their longevity.
The process of oil weathering in saltwater environments is relatively well understood, but the behavior of oil in freshwater environments is still being investigated. To address this gap in knowledge, Dena McMartin and her colleagues conducted a study to simulate a freshwater oil spill in a laboratory setting. They combined water and river sediment from the North Saskatchewan River in Alberta, Canada, with conventional crude oil obtained from a pipeline operator. The simulation was carried out at around 75 degrees Fahrenheit for 56 days, with water samples taken at multiple time points for analysis using Fourier-transform ion cyclotron resonance (FT-ICR) and ion trap mass spectrometry. These techniques provided detailed insights into the chemical makeup of the oil mixture as it underwent weathering.
The results of the study revealed that as the oil weathered, certain compounds incorporated more oxygen atoms, leading them to become more persistent in water. This accumulation of oxygen-loaded chemicals could potentially have a greater impact on aquatic organisms, as higher concentrations of these compounds build up. The increase in oxygen atoms was particularly observed in sulfur oxide compounds, as well as some other classes of compounds present in the crude oil mixture. These findings underscore the importance of rapid responses to oil spills and could help establish benchmarks for long-term remediation efforts to mitigate the environmental impact.
The research conducted by McMartin and her team was supported by funding from various sources, including the National Science Foundation, the Engineering Council of Canada, and the Oceans Protection Plan of the Government of Canada. This support highlights the importance of ongoing studies to better understand the behavior of oil in freshwater environments and the potential risks it poses to aquatic ecosystems. By gaining a deeper understanding of the chemical changes that occur in oil spills over time, scientists can develop more effective strategies for responding to and mitigating the environmental impact of such incidents. The findings from this study provide valuable insights that could inform future approaches to managing oil spills and protecting freshwater ecosystems.
