Application of Plants in the Removal of Oil Contaminants

The oil industry is an important, job-creating, and feeder industry whose products are used as raw materials for other industries. One of the important environmental problems related to this industry is that oil can leak into the environment during extraction, transfer, refining, and processing. Environmental oil pollution poses a major threat to the ecosystem and human health. Therefore, the elimination of oil contaminants entering the environment, especially soil, is essential for environmental health. The current study aims to provide general information about phytoremediation and review the latest research on the use of different plants to remove oil pollutants from the environment. Additionally, several plant species with the ability to remove oil pollutants have been introduced.

To conduct this study, the electronic libraries of Elsevier, Springer, and Science Information Center (SID) were searched using the keywords Phytoremediation, Oil Contamination, Plant Remediation, Oil Pollution, and Oil Pollutant. The sources were analyzed after extraction and subject classification.

By exploring the sources of scientific information, 10 review articles were extracted as the core and a total of 99 references were extracted and analyzed. Based on the findings, the use of plants to remove all kinds of pollutants has been introduced as one of the cost-effective and environmentally friendly methods. Among the advantages of phytoremediation, the following were mentioned: The need for small financial investment, the possibility of removing pollutants on site, proper aesthetics, preventing soil erosion, preventing the release of toxic substances, and the possibility of using this method in areas with low pollutant concentrations. According to studies, plants utilize various mechanisms, including phytoextraction, phytovolatilization, phytostabilization, phytodegradation, rhizodegradation, or rhizofiltration to remove pollutants from environments. In this study, 12 plants effective in removing heavy metals and 30 plants capable of phytoremediation of oil and related toxic compounds, i.e. polycyclic aromatic hydrocarbons, were introduced. 

Phytoremediation is an environmentally friendly method that is based on solar energy. It is economically reasonable and its commercialization is possible. Currently, phytoremediation technology is in its early stages and there are many technical problems to be overcome for its development. Among plants, herbaceous plants because of their high root surface area are efficient in the removal of polycyclic aromatic hydrocarbons. Currently, especially in our country, there is an urgent need to discover new plant species with the ability to tolerate and remove environmental pollutants such as oil pollution. It is also necessary to carry out research to optimize plant treatment processes, understand plant–environment interactions, and microbial interactions and finding appropriate equipment to do it. In addition, the use of molecular techniques and the development of transgenic plants to increase the efficiency of the plant to remove toxic materials are expanding. Therefore, genetic engineering is expected to play an important role in increasing the application of plant breeding technologies. Studies on these strategies will be very useful in developing simpler and cost-effective tools for phytoremediation.