Greenhouse Assessment of Phytoremediation Efficiency for Petroleum Contaminants in Clay and Saline Soil

Petroleum contaminated soil is an environmental problem that affects human health. Phytoremediation is a cost-effective method for removal of petroleum from soil. This study evaluated the effects of the plant and nutrients on the removal of total petroleum hydrocarbons (TPHs) from the soil.

Soils were collected from Ahwaz desalting unit No. 2 and then polluted with 2. 5% w/w of crude oil. Microbial number and residual TPHs of the studied pot experiments were determined at day 0 and 90. TPHs and heterotrophic bacterial number were measured by gas chromatography (GC) and heterotrophic plate count (HPC) method، respectively.

The average percentage of TPH removal in the rhizosphere soil (≈ 20%) was higher than those in the non-rhizosphere soil (≈ 7%). In addition، the average number of heterotrophic bacteria in the rhizosphere soil (7. 14 CFU/g) was higher than in the non-rhizosphere soil (6. 16 CFU/g). Moreover، the TPH removal and microbial number in the soil that received nutrient were higher than in the free-nutrient soil.

Although high clay and salinity of the soil had an inhibitive effect on phytoremediation efficiency، results showed a native plants performed phytoremediation properly even in improper condition of environment.