Enzyme Responses to Phytoremediation of PAH-Contaminated Soil Using Echinacea purpurea (L.)

Abstract

Pot-culture experiments were performed to study the relationship between enzyme activity and polycyclic aromatic hydrocarbon (PAH) degradation by sowing Echinacea purpurea (L.) in aged PAH-contaminated soils. E. purpurea (L.) was cultivated in PAH-contaminated soils for 60, 120, and 150 days. The data showed that the rate of removal of fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benz(a)pyrene, and dibenzo(a,h)anthracene was 92.92 % at 150 days. Furthermore, there was a better recovery of these eight PAHs from the PAH-contaminated soils in comparison with the unplanted soils at 120 days, and the recovery from the PAH-contaminated soils was higher than that from the control soils. Significant reductions were detected in the levels of these eight PAHs, corresponding to 96.21, 94.53, 97.35, 90.70, 99.64, 97.34, 86.67, and 89.90 %, respectively. The activities of dehydrogenase, polyphenol oxidase, and urease increased as a result of PAH treatment, and these effects were suppressed over time. The activities of peroxidase and alkaline phosphatase were reduced, which suggests that these enzymes are sensitive to PAHs. The data in this study revealed that enzyme activities were strongly correlated to the higher degradation performance of the E. purpurea (L.) plant on PAH-contaminated soil. More researches are required to elucidate the mechanisms underlying PAH detoxification and degradation in contaminated soil.