Methods of Bioremediation for Oil Spills

Microbes

• Microbes are commonly used to dissolve oil, among other substances, in marine environments. Microbes can only be used when the water temperature is just right, there is enough oxygen in the water, and enough fertilizers are present. A small number of microbes are introduced in the area of the oil spill, where they grow and multiply, digesting oil and transforming it into water and gases. This is a beneficial method of bioremediation since it eliminates humans from the dangerous cleanup process.

Soil Bioremediation

• When an oil spill reaches the shoreline oil gets stuck in the soil and is extremely difficult to clean manually. This can pose a danger to groundwater, which is often used as drinking water, and introducing microbes alone does not always work. The Environmental Protection Agency will sometimes drill wells to move groundwater to tanks, where it is then mixed with microbes and a mixture of nutrients and air to remove the oil. The water is then pumped back into the ground, where the microbes die out since there are no more nutrients to be consumed.

Fertilization

• Some indigenous plants produce their own microbes that can dissolve oil. In these cases it makes more sense to feed the plants rather than introduce a new species of microbes. According to a 1991 study by the United States Congress Office of Technology Assessment, naturally occurring microorganisms exist in every marine environment, though no single microorganism can degrade every type of oil. This method can be preferential to introducing new microorganisms since existing species do not have to adapt to a new temperature range, pH level or salinity level.

Safety

• The EPA claims that microbes do not pose a threat to humans but there are some safety concerns surrounding bioremediation, since it is a relatively new and unstudied process. However the Bureau of Ocean Energy Management, Regulation and Enforcement said that introducing microbes to a salt marsh "did not adversely affect the marsh macrophyte, S. alterniflora, various microbial populations and soil respiration, and various infaunal animals including macrofauna and meiofauna."