Phytoremediation of Petroleum‐Contaminated Soils byVetiveria zizanioides(L.) Nash

Abstract

Phytoremediation of petroleum and its derivatives has frequently been regarded as a practical, eco-friendly alternative to the clean-up of petroleumcontaminated soils. In this study, Vetiveria zizanioides (L.) Nash (vetiver) is shown to efficiently remediate two petroleum-contaminated soils; fresh contamination (FC) with 3500 mg kg À1 aliphatic petroleum hydrocarbons (APH), and aged contamination (AC) with 700 mg kg À1 . An 88.5% reduction in the concentration of APH is observed in both contaminated soils where vetiver are grown for 15 months. Vetiver vegetation also doubled (FC) and tripled (AC) the bioavailability of contaminants as compared with unvegetated soils, as determined by the release of APH into the soil solution. The carbon availability index increased in both vegetated soils (%1), and the microbial biomass carbon shows a three-and five-fold increase in vegetated soils FC and AC, respectively, leading to a fourfold decline in the metabolic quotient. The mRNA level of nosZ gene increased significantly in the soils under vetiver vegetation, and was correlated with the accumulation of APH in the soil solution; this probably demonstrates the role of hydrocarbon bioavailability in promoting biological processes and biodegradation. It is concluded that vetiver vegetation increased hydrocarbons bioavailability and hence raised the extent of biodegradation hydrocarbons in the soil.

An Sustainable Strategy for Reuse Agriculture Soil Impacted by A Mixture of Hydrocarbons

“…In that sense phytoremediation of soil polluted by WMO sowing H.annus enhanced with B. vietnamiensis and P. polymyxa was achieved the maximun reduction in WMO concentration to 1;000 ppm registered in 2 months; at the same time H. annuus without WMO phytotoxicity stress; supported that B. vietnamiensis and P. polymyxa converted H. annuus seed exudates and organic compounds derived from root metabolism into phytohormones ; which increased the root uptake capacity of the minerals N; PO4-3 (phosphates) and K (potassium); that increases the tolerance of H. annuus to WMO [25]. While it is supported that B. vietnamiensis and P. polymyxa at the root level of H. annuus had a positive effect on the partial hydrolysis of some WMO aromatics and effective mineralization that reduced their concentration; to concentration value lower than the highest value accepted by NOM-138 [24,25]. On the opposite way; H. annuus without B. vietnamiensis or P. polymyxa in the non-biostimulated or NC soil; there the excess of WMO forms a hydrophobic film that adheres to the H. annuus seeds and prevented germination and caused their death.…”