[Assessment of bioaccessibility of PAHs in microbial degradation process using solid phase micro extraction and solid phase extraction].

In order to demonstrate the variation of bioaccessibility of PAHIs in microbial degradation process, PAH contaminated coking plant soil was remediated using microbial agent, and the bioaccessibility of PAHs was assessed using solid phase micro extraction (SPME) and solid phase extraction (SPE), difference and correlation between PAH degradation and PAH bioaccessbility variation were also analyzed. Results showed that the dominant PAHs in the coking plant soil and its pore water were low molecular weight (LMW) PAHs, and 68.3% of total PAH was degraded by the microbial agent, which was mainly due to the LMW PAH degradation. Decrease of PAH concentration in soil pore water was also contributed by LMW PAHs, however, individual PAH reductions in soil pore water were lower than those PAH degradations. Fast desorption fraction was calculated from Tenax-TA extraction, and those fractions for LMW PAHs decreased, while those for high molecular weight (HMW) PAHs did not change significantly. Strong correlation between PAH degraded and PAH concentration in soil pore water or fast desorption fraction of Tenax-TA extraction was observed. The results above demonstrated that PAH concentration in soil pore water and fast desorption fraction of Tenax-TA extraction can be used to predict PAH degradation in soil, which provided some theoretical basis for the remediation of PAH contaminated soil from coking plant.