Study on changes of plant and soil δ15N under soil petroleum contamination

Bioremediation of soil petroleum contamination was studied by monitoring changes of Leguminosae plant, no Leguminosae plant (Agropyron cristatum and Trioflium repens) and soil nitrogen isotopic composition, for a time period of plant growing 1 month. Results showed that under different soil petroleum contaminated concentrations, δ¹⁵N of Agropyron cristatum and Trioflium repens changed significantly. Agropyron cristatum and Trioflium repens δ¹⁵N decreased with soil petroleum contamination concentration increased. δ¹⁵N values of Agropyron cristatum were more positively than δ¹⁵N values of Trioflium repens. Contrast to soil δ¹⁵N values with planted Agropyron cristatum, soil δ¹⁵N with planted Trioflium repens was steady under different soil petroleum contaminated concentrations. This may be related to Trioflium repens has ability to fixed nitrogen in the air to compensate nitrogen shortage in the soil, which imply that using Leguminosae plant, Trioflium repens as bioremediation plant is more useful than no Leguminosae plant, Agropyron cristatum. The study results shows that δ¹⁵N of plant and soil can be use to indicate the effect of bioremediation. More study work of plant and soil isotopic composition(C, N) research under soil petroleum contamination should be done, which can give us more accurate information about effect of bioremediation of plant and microbial under soil petroleum contamination.