Bioremediation of oil spills
Bioremediation of petroleum contaminated environments is a process in which the biological pathways within microorganisms or plants are used to degrade or sequester toxic hydrocarbons, heavy metals, and other volatile organic compounds found within fossil fuels.
Oil spills happen frequently at varying degrees along with all aspects of the petroleum supply chain, presenting a complex array of issues for both environmental and public health.
[2][3] The efficiency and effectiveness of bioremediation efforts are based on maintaining ideal conditions, such as pH, RED-OX potential, temperature, moisture, oxygen abundance, nutrient availability, soil composition, and pollutant structure, for the desired organism or biological pathway to facilitate reactions.
Bioremediation has been implemented in various notable oil spills including the 1989 Exxon Valdez incident where the application of fertilizer on affected shoreline increased rates of biodegradation.
[12] Chemical solvents and dispersants were briefly used by Exxon in water surrounding the Valdez although discontinued as they required specific conditions and contained carcinogenic compounds.
[12] Bioremediation techniques used in the Exxon Valdez spill included nitrogen and phosphorus seeding along coastline increasing available nutrients for indigenous petroleum degrading microorganisms doubling rates of decomposition.
[12] Many genera of plant, microbes, and fungi have demonstrated oil remediating properties including Spartina, Haloscarcia, Rhizophora, Nocardioides, Dietzia, and Microbacterium.
Various types of bacteria, archaea, algae, fungi, and some species of plants are all able to break down specific toxic waste products into safer constituents.
[20] Dependent on physical and chemical properties, petroleum-degenerative microorganisms take longer to degrade compounds with high-molecular-weight, such as polycyclic aromatic hydrocarbons (PAH's).
Plants secrete sugars, enzymes, and oxygen from roots which provide necessary substrates for rhizobia and associated rhizosphere microbes to stimulate degradation of organic pollutants.
[23] Studies have demonstrated the bioaccumulation abilities of various plants with rhizobial associations, in particular Chromolaena odorata were able to remove 80% of petroleum and heavy metal toxins from soils.
[27] Polycyclic aromatic hydrocarbons (PAH) concentrations of soil samples taken from contaminated oil drilling cuttings in Nigeria have been decreased by 7% to 19% using white rot fungi under experimental conditions.
[30] Environmental factors such as requirements of reaction, mobility of substances, and physiological needs of organisms will affect the rate and degree that contaminants are degraded.
[30] Methane, Metals, Carbon Dioxide, Water Uraninite Listed above, the chemicals required and products formed in petroleum degradation are shown.
