بررسي پالايش هاي خاك هاي آلوده به هيدروكربن هاي نفتي اطراف پالايشگاه تهران به روش تحريك گياهي

Remediation of petroleum contaminated soils around the Tehran oil refinery using Phytostimulation method

Total petroleum hydrocarbons (TPHs) are important sources of soil and environmental pollution in our country especially around oil refineries. In this study, the capability of phytostimulation technique as a cost-effective method for remediation of these contaminants from soil was evaluated. Therefore, first the germination and subsequent growth of seven plants were tested in a soil with different petroleum contamination levels (C| and C2) compared to uncontaminated soil (soil C0). Thereafter, the best plant genotypes were selected for phytoremediation trials. Results showed that the presence of TPHs in the soil had no effect on germination of agropyron, white clover, sunflower and safflower seeds. Canola and white clover seedlings were sensitive to these compounds and failed to produce dry matter yield (DMY) at the end of experimental period. But, the presence of petroleum contaminants in soil had a negligible effect on agropyron and tall fescue growth. Therefore, only four plant genotypes including agropyron, tall fescue, safflower and sunflower were selected for later phytoremediation trials. DMY was significantly reduced by the presence of TPHs in all contamination treatments compared to control. The higher TPH-reduction was found in the rhizosphere of agropyron and tall fescue. There were 71 and 69% decreases in TPH-concentration in C| treatment, 45 and 42% decreases in C2 treatment with the presence of agropyron and tall fescue, respectively. Furthermore, the sunflower had no significant effect on contaminant removal at the end of the experiment. Microbial activity in the rhizosphere of agropyron was more than tall fescue in C2 treatment but no significant differences were observed in the rhizosphere of sunflower and safflower compared to control (unplanted). According to this study, although advanced studies for assessing the suitability of plant species and improving phytoremediation efficiency are necessary, some genotype like agropyron showed to be suitable choices for phytoremediation of the investigated petroleum contaminated soil.