Phytoremediation of soils contaminated with crude and weathered oil using two rice varieties (Oryza sativa L.)

Abstract

Objective: To evaluate the potential for soil phytoremediation with new and weathered hydrocarbons with two rice varieties (Oryza sativa L.). Materials and Methods: The assessed treatments were 150 mg kg-1 (control soil), 30,000; 60,000 and 90,000 mg kg-1 of new oil and 79,457 mg kg-1 of weathered oil 1 and 42,000 of mg kg-1 of weathered oil 2; they were established in a completely randomized design with 6 x 3 factorial, with four repetitions each. The evaluated variables were populations of total bacteria (colony forming units CFU per grams of dry soil), free-living nitrogen-fixing bacteria (CFU), total fungi (CFU), and total dry biomass (g). Total bacteria and fungi were quantified at the beginning of the experiment at 90 and 145 days. Results: The highest total petroleum hydrocarbons (HTP) degradation was 73 and 72 % in the 79,457 and 42,000 mg kg-1 concentrations of weathered HTP 1 and 2, in the rhizosphere of rice silver line 21. The total dry biomass reported significant differences (p ≤ 0.05), evidencing a lower effect in the 60,000 mg kg-1 concentration in new oil, which caused a 33 % reduction compared to the control. Results/Conclusions: The rice variety line 21 has a greater potential to phytoremediate soils contaminated with crude and weathered oil in field conditions in tropical areas.