Evaluation of the Growth and Phytoremediation Ability of Ornamental Tall Fescue and Sunflower in Contaminated Soils to Petroleum Hydrocarbons

Petroleum sludge is the waste of crude oil refining processes, and are the most priority organic pollutants found in the environment. The present study was carried out to evaluate the growth and phytoremediation ability of ornamental tall fescue (Festuca arundinacea Schreb.) and sunflower (Helianthus annuus L.) plant to petroleum sludge produced by Isfahan Refinery in contaminated soils in a greenhouse experiment. For this purpose, the air-dried petroleum sludge sample was added to an uncontaminated soil at ratios of 0 (control), 10 and 20% (w/w) and mixed thoroughly. Plastic pots were filled with called mixture (3 kg). The experiment layout consisted of split-plots arranged in a completely randomized design with three replicates. The results showed that with increasing sludge level from 0 to 10 and 20 %, the tall fescue germination decreased significantly (P<0.01). In sunflower plant this decrease was not significant. The mean values of plant heights and root and shoot dry weights for tall fescue only in 20% level of petroleum sludge showed a significant reduction when compared with control. However, in sunflower plant, this reduction was not significant in all three petroleum sludge levels (P<0.01). The highest reduction of total petroleum hydrocarbons (89%) in tall fescue rhizosphere was observed in petroleum sludge level of 10%. By increasing the petroleum sludge up than 10%, total petroleum hydrocarbons in rhizosphere of two plants significantly decreased (P<0.01). Because, tall fescue plant produces more roots than shoots and have more fibrous root systems that caused more reduct TPH, application this plant recommend as a appropriate species for phytoremediation of contaminated soils to petroleum sludge of Isfahan Refinery.