Study on vertical migration of phytoremediation for petroleum-contaminated soil

The total petroleum hydrocarbon (TPH) was observed after 120 days phytoremediation at five depths with different petroleum contamination grads, namely 0∼−20cm, −20∼−40cm, −40∼−60cm, −60∼−80cm, and −80∼−90cm. The change of TPH with increasing soil depth for different agrotype was analyzed. As demonstrated in this work, the TPH for three kinds of agrotype was reduced gradually with increasing depth of different petroleum contamination grads. For low concentrations of Trioflium repens -loess in Gaoling and Trioflium repens -loess in Northern Shaanxi phytoremediation areas, the TPH would not migrate till the depth of −80∼−90cm, but did for moderate and high contamination concentrations area. The residues TPH of Trioflium repens-loess in Gaoling were lower than Lolium perenne L -loess in Gaoling.