Phytoremediation of Petroleum-Contaminated Soils Around Isfahan Oil Refinery (Iran) by Sorghum and Barley

Petroleum compounds are one of the most frequently encountered pollutants in soils adjacent to oil refineries. Phytoremediation, where feasible, has become a cost-effective alternative to physicochemical methods of soil remediation. In this study, sorghum (Sorghum bicolor) and barley (Hordeum vulgare) were selected for phytoremediation and the diminution in the concentration of oil-based contaminants was measured during a 90-day period. Contaminated and control treatments were compared in terms of root and shoot dry weight. Comparisons revealed reductions of about 22% and 30% in root dry matter and 51% and 42% in shoot dry matter of sorghum and barley in contaminated soil, respectively. The control and planted soils were significantly different in total and oil-degrading bacterial counts. Moreover, the concentration of total petroleum hydrocarbons decreased by 52%-64% in 90 days. Since planting the contaminated soil with sorghum and barley resulted in an improvement of 30% compared to unplanted contaminated soil, the two plants were highly efficient in removing petroleum from oil-contaminated soils. Therefore, despite the necessity of further studies to enhance the efficacy of phytoremediation by assessing the appropriateness of various plant species, some genotypes like sorghum and barley were found suitable choices for phytoremediation of the investigated petroleum-contaminated soil.