Effect of bioaugmentation to enhance phytoremediation for removal of phenanthrene and pyrene from soil with Sorghum and Onobrychis sativa

The use of plants to remove poly-aromatic-hydrocarbons (pahs) from soil (phytoremediation) is emerging asa cost-effective method. phytoremediation of contaminated soils can be promoted by the use of addingmicroorganisms with the potential of pollution biodegradation (bioaugmentation). in the present work, the effect ofbacterial consortium was studied on the capability of sorghum and onobrychis sativa for the phytoremediation ofsoils contaminated with phenanthrene and pyrene. 1.5 kg of the contaminated soil in the ratio of 100 and 300 mgphenanthrene and/or pyrene per kg of dry soil was then transferred into each pot (nine modes). the removalefficiency of natural, phytoremediation and bioaugmentation, separately and combined, were evaluated. the sampleswere kept under field conditions, and the remaining concentrations of pyrene and phenanthrene were determinedafter 120 days. the rhizosphere as well as the microbial population of the soil was also determined. results indicatedthat both plants were able to significantly remove pyrene and phenanthrene from the contaminated soil samples.phytoremediation alone had the removal efficiency of about 63% and 74.5% for pyrene and phenanthrenerespectively. in the combined mode, the removal efficiency dramatically increased, leading to pyrene andphenanthrene removal efficiencies of 74.1% and 85.02% for onobrychis sativa and 73.84% and 85.2% for sorghum,respectively. according to the results from the present work, it can be concluded that onobrychis sativa andsorghum are both efficient in removing pyrene and phenanthrene from contamination and bioaugmentationcan significantly enhance the phytoremediation of soils contaminated with pyrene and phenanthrene by 22%and 16% respectively.