Much has been made of the role that marine microorganisms can, and sometimes do, play in the breakdown of oil after a spill. Scientists around the world are looking at ways to improve the efficiency of this process. One such initiative is the EU funded Spill-Kill.
Enhancing natural remediation of oil spills
Research following the Deepwater Horizon spill found a group of microorganisms that broke down some components of the oil very quickly; however, other components were not affected by these organisms and remain in the environment, highlighting the limits of natural bioremediation in the face of large quantities of oil. Spill-Kill’s primary goal is to improve this process.
In addition, Kill-Spill will address some of the concerns raised about the use of dispersants and other products, starting with an analysis of the gaps in the knowledge of all types of remediation. For example, Dioctyl sodium sulfosuccinate (DOSS), a chemical dispersant was one of the products used to break up the oil from the Deepwater Horizon spill. A recent study showed that DOSS could still be found in oil soaked sand patties four years after the spill. The quantities are very low and may not represent a risk of toxicity but the long-term persistence of this product was unexpected.
The fourteen Universities, four research institutions, fourteen Small or Medium-sized Enterprises (SMEs) and one oil spill industry trade association that are involved in the Spill-Kill project will also look at methods for measuring biodegradation efficiency. Open ocean tests of new bioremediation products are planned. Determining which products including dispersants, sorbents and multifunctional agents, can be safely used together and the ways in which each may affect the marine food chain is another aspect of this project.
Not all bioremediation is without potential harm to wildlife
Enhanced bioremediation, while showing promise for less toxic oil spill remediation, needs to be carefully assessed. These microorganisms, which exist in the natural environment, still have the potential to have a negative impact under some conditions. For example, to increase numbers of bacteria, nitrogen and phosphorus are being provided as food sources in the laboratory. These two chemicals are also found naturally in the environment, but have been shown to contribute to Harmful Algal Blooms (HABs) when present in high concentrations, often in areas of heavy human coastal use.
The project is using fermented vegetable oils, which act as a dispersants, breaking the oil into smaller droplets, which make it easier for the microorganisms to get at the oil. But vegetable oil can have negative effects of birds, as was shown in at least two incidents, one in the US and one in the UK. In both cases, the birds were unable to fly after their wings became coated in refined vegetable oils. These oils are not toxic if ingested and survival rates were higher than generally expected during a petroleum spill but both cases resulted in bird deaths.
As Dana Wetzel of the Environmental Laboratory for Forensics at Mote Marine Laboratory in Florida, commented in an article on PHYS.ORG, a science news website:
“All spill remediation strategies, including biological ones, have the potential to impact natural ecosystems in ways that might not be immediately obvious, so resource managers have a challenging job in choosing potential remediation strategies, especially because each spill is different.”
Using the information gathered by the Spill-Kill project, progress may be made in reducing the use of the chemical dispersants presently employed in oil spill response. As long as fossil fuels continue to be an important source of energy there will be oil spills, thus, any methods which reduce the environmental impact of those spills are important to maintaining ocean health.