Rhizoremediation of petroleum and heavy metal-contaminated soil using rhizobacteria and Zea mays

In this study, the rhizoremediation of petroleum and heavy metal-contaminated soil was characterized employing Zea mays and two plant-growth promoting rhizobacteria, Gordonia sp. S2RP-17 and Serratia sp. SY5 which have petroleum-degrading activity and heavy metal-resistance, respectively. After 51 days, the average dry weights of Zea mays' root without and with the inoculation of rhizobacteria were 1.9±0.2 and 5.6±0.7 g, respectively. Compared with initial TPH concentration in soil (21,576±3,426 mg-TPH·kg-dry soil^-1), the residual TPH concentrations were 220±98 mg-TPH·kg-dry soil^-1 in soil planted with Zea mays, and 20±41 mg-TPH·kg-dry soil^-1 in soil planted with Zea mays and inoculated with rhizobacteria. These results indicated that the inoculation of S2RP-17 and SY5 could promote TPH removability in soil as well as the growth of Zea mays' root. There was little positive effect of the rhizobacteria inoculation on the removability of heavy metal such as Cu, Cd and Pb in soil planted with Zea mays.