Remobilization and bioavailability of polycyclic aromatic hydrocarbons from estuarine sediments under the effects of Nereis diversicolor bioturbation.
The effects of Nereis diversicolor bioturbation on the remobilization and bioavailability of polycyclic aromatic hydrocarbons from estuarine sediment were determined after 60 d in a laboratory experiment. The release fluxes and mass transfer coefficients showed that bioturbation by N. diversicolor can lead to a significant remobilization of polycyclic aromatic hydrocarbons (PAHs) from estuarine sediments. Bioturbation enhanced the release of PAHs from sediment to water by accelerating the transport of sediment particles to the sediment-water interface followed by PAHs desorption to the water. The bioavailability of PAHs was described by SPMD-sediment accumulation factors (SSAF). The SSAF of low molecular weight PAHs with bioturbation was significantly higher than that of PAHs without bioturbation, and there were no significant variations in high-molecular-weight PAHs. Our results revealed that N. diversicolor bioturbation significantly increased PAHs release from sediment to water but only increased the bioavailability of low-molecular-weight PAHs.