Accumulation of polycyclic aromatic hydrocarbons from contaminated soil by Kandelia candel

The purpose of this study was to investigate the accumulation behavior of two typical PAHs, phenanthrene (PHE) and fluoranthene (FLA), uptaken by the mangrove Kandelia candel in various treated sandy soils. The experiment lasted for three months. Soil and plant samples were collected after 3, 6, 9 and 13 weeks of the incubation and the levels of PAHs were analyzed using a GC/MS (HP6890-5975B). The results showed that the root accumulations of PHE and FLA were elevated with the increase of the PAH concentrations in the soil. With prolonged exposure time, PHE and FLA concentrations of the roots increased significantly in comparison with the control. PHE and FLA concentrations of root after 13 weeks of treatment ranged from 0.28 to 4.36 μg·g^-1 and 0.79 to 35.76 μg·g^-1, respectively. The calculated mean values of the root concentration factors were 0.58 for PHE and 0.71 for FLA. This indicated that root accumulation of FLA was greater than PHE, which would result from the higher octanol-water partition coefficient (K_ow) of FLA. These results underline the ability of mangroves to remove PAHs from contaminated marine substrates and hence their potential use in bioremediation and the removal of PAHs from the marine food chain.