Ability of White Clover and Alfalfa to Grow in Petroleum Hydrocarbon-Contaminated soil in Iran and their Phytoremediation Potential

Over the past decades rapid growth in industrial and agricultural activities, waste disposal and etc., have significantly contributed to extensive soil contamination. Total petroleum hydrocarbons (TPHs) are one of the most common groups of persistent organic contaminants. To date, many developing countries like Iran have almost completely relinquished remediation of oil-polluted soils due to the high costs of conventional soil remediation methods. The main objectives of this study were to investigate the influence of petroleum hydrocarbons on growth characteristics of White Clover (Trifolium repens L.) and Alfalfa (Medicago sativa L.) as well as to evaluate the phytoremediation capability of the these plant species in aged hydrocarbon contaminated soil in Iran. Impact of organic fertilization on plant growth in contaminated soil and phytoremediation effectiveness was also evaluated. Soil samples were analyzed for TPHs content by GC-FID. Adverse effect of petroleum hydrocarbon contamination on growth parameters of both studied plant species was observed in this research; however, hydrocarbon contamination could not inhibit their germination and growth, especially in organic amended soil. The highest removal of TPHs was obtained for white clover in presence of peat (88.1% removal). Results demonstrated that white clover and alfalfa are promising species for phytoremediation of aged, petroleum hydrocarbon-contaminated soils. Phytoremediation as a novel technology to remediate hydrocarbon contaminated sites has been received increasing attention in recent years; however, there is still a significant need to pursue both fundamental and applied research to provide comprehensive insight into its effectiveness under various environmental conditions.