Abstract: By using four immobilized microbial agents TB02, TB07, TBB03 and TBB08, the degradation of soil phenanthrene, anthracene, pyrene, chrysene and benzo(a)pyrene was studied, and fitted with Michaelis-Menton and Monod dynamic models. The results showed that all the agents had the ability of degrading test polycyclic aromatic hydrocarbons (PAHs), among which, TB02 was most effective. Under the action of TB02, the degradation of test PAHs was faster, halflife was the shortest, while the cost was lower. On the contrary, TB07 required more time to fully display its degradation ability. When the phenanthrene, anthracene, pyrene, chrysene, and benzo(a)pyrene had an initial concentration of 20 mg·kg^-1, their degradation rate by TB02 after 42 days was 84.32%, 85.24%, 82.59%, 43.75% and 62.25%, and that by TB07 after 133 days was 95.00%, 95.24%, 90.93%, 74.82% and 72.20%, respectively. Through the comparison of the half-life of test PAHs, it was indicated that the degradability of these PAHs was decreased in the order of henanthrene>anthracene>pyrene>benzo(a)pyrene>chrysenemodel.

Key words: di(2-ethylhexyl) phthalate (DEHP), Ipomoea aquatica, Paddy soil, Accumulation