Efficiency of five ornamental plant species in the phytoremediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soil

Pot-culture experiments were conducted to assess the phytoremediation potential of five ornamental plant species on polycyclic aromatic hydrocarbon (PAH)-contaminated soils obtained from the Shengli Oil Field, one of the largest oil fields in China. The removal rate of eight PAHs (fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluorant-hene, benzo(a)pyrene and dibenzo(a,h)anthracene) was examined after 60, 120 and 150 days. The results showed that Fire Phoenix and Medicago sativa Linn effectively reduced the PAH content in contaminated soil. After a 150-day pot-culture experiment, the removal rates for eight target PAHs were 86.56% and 90.67% of fluoranthene, 93.27% and 79.53% of pyrene, 100% and 100% of benzo(a)anthracene, 100% and 100% of chrysene, 100% and 100% of benzo(b)fluoranthene, 100% and 100% of benzo(k)fluorant-hene, 99.53% and 99.6% of benzo(a)pyrene, 100% and 100% of dibenzo(a,h)anthracene respectively from Fire Phoenix and Medicago sativa Linn. The removal rates for these two plant types were significantly higher than those of other tested ornamental plants. The results suggested that Fire Phoenix and Medicago sativa Linn should be applied to the phytoremediation of PAH-contaminated soil. Furthermore, soil physicochemical properties (e.g., the alkali-hydrolyzable nitrogen, available phosphorus and cation exchange capacity) was also measured in the soil before and after plant growth and indicated that Fire Phoenix is better able to improve soil physicochemical properties (mainly about available phosphorus and cation exchange capacity).