en بهداشت محیط زیست Environmental Health پژوهشي Original Article <div style="text-align: justify;"><strong>Background and Purpose:</strong> Phytoremediation efficiency of heavy metals is an important factor in environmental studies. This study was conducted to investigate the effect of multi-walled carbon nanotubes (MWCNTs), zeolite, and P.indica on bio-degradation of mazut in a soil treated with Cd and mazut.<br> <strong>Materials and Methods:</strong> Treatments consisted of applying zeolite (0, 1 and 2% (W/W)), MWCNTs (0, 1 and 2 % (W/W)) in the presence and absence of P.Indica in the Cd (0 , 5 and 10 mg/kg soil) polluted soil that was simultaneously polluted with mazut (0 and 6 % (W/W)). After 70 days, plants were harvested, and plant and soil Cd were measured using AAS. In addition, the degradation percentage of mazut in soil was determined.<br> <strong>Results:</strong>&nbsp;The addition of 2 % (W/W) MWCNTs and zeolite to the soil polluted with 6 % (W/W) mazut significantly increased the bio-degradation percentage of mazut in the soil by 11.3%. For soil and plant Cd concentration, it was decreased by 10.6 and 12.8%, respectively. In addition, plant inoculation with P.indica significantly increased the biodegradation of mazut in the Cd polluted soil (10 mg Cd/kg soil) by 14.3%. Increasing soil pollution to mazut from 0 to 6 % (W/W) significantly increased the soil microbial respiration by 14.4%.<br> <strong>Conclusion:</strong> Based on the results, the addition of MWCNs and zeolite in the soil and plant inoculation with P.indica significantly increased the mazut bio-degradation in the soil. However, the amount and type of pollutant had a significant effect on phytoremediation efficiency.&nbsp;&nbsp;<br> &nbsp;</div> Pollution, Phytoremediation, MWCNTs, Zeolite, Microbial Respiration 28 39 http://jhs.mazums.ac.ir/browse.php?a_code=A-10-676-8&slc_lang=en&sid=1 Amir Hossein Baghaie امیر حسین بقائی a-baghaie@iau-arak.ac.ir 10031947532846007785 10031947532846007785 Yes Department of Soil Science, Arak Branch, Islamic Azad University, Arak, Iran دانشگاه آزاد اسلامی اراک