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− | <b | + | <b>Contamination of aquatic and terrestrial environments with crude oils (or petroleum) represents a serious problem worldwide that results in both immediate and long-term environmental damages with toxicity to plants and/or soil invertebrates, as well as risks to humans and wildlife. Crude oils, while made of complex mixtures of thousands of types of molecular compounds, are predominantly composed of hydrocarbons including linear alkanes and aromatic hydrocarbons based on a 6-carbon ring account for approximately 80% of the total petroleum hydrocarbons in crude oils. Aromatic carbons such as polycyclic aromatic hydrocarbons (PAHs) like fluorene and phenanthrene are the molecular compounds in oil that are the most toxic as they can be quite persistent in the environment due to their intrinsic stability provided by the aromatic ring. |
Contamination cleaning up processes include skimming the oil into containment tanks - an approach that cannot be applied on high seas and bad weather conditions- and in situ burning - an approach that may create additional pollutants. Chemical dispersants are sometime added to break down oil spills; however, the breakdown products may be absorbed by marine organisms and thus entered the food chain. | Contamination cleaning up processes include skimming the oil into containment tanks - an approach that cannot be applied on high seas and bad weather conditions- and in situ burning - an approach that may create additional pollutants. Chemical dispersants are sometime added to break down oil spills; however, the breakdown products may be absorbed by marine organisms and thus entered the food chain. | ||
Clearly, bioremediation using microorganisms that naturally use crude oil as a source for growth and at the same degrade it, is the preferred approach. Up to now, bioremediation approaches have mostly targeted microorganisms already present in the ecosystem where the oil spill occurs. However, this approach has limited results because the decontamination can take decades because of slow degradation rate. Fertilizers such as nitrogen and phosphorous may be added to enhance their activities with the risk of local pollution. The newest bioremediation products include mixture of microorganisms that are able to deplete linear alkanes whereas the PAH class may not be degraded at all. | Clearly, bioremediation using microorganisms that naturally use crude oil as a source for growth and at the same degrade it, is the preferred approach. Up to now, bioremediation approaches have mostly targeted microorganisms already present in the ecosystem where the oil spill occurs. However, this approach has limited results because the decontamination can take decades because of slow degradation rate. Fertilizers such as nitrogen and phosphorous may be added to enhance their activities with the risk of local pollution. The newest bioremediation products include mixture of microorganisms that are able to deplete linear alkanes whereas the PAH class may not be degraded at all. |
Revision as of 05:19, 29 October 2017