固相微萃取和固相萃取评价多环芳烃降解过程中的生物有效性变化

为了揭示多环芳烃(PAHs)降解过程中的生物有效性变化规律,应用PAHs降解菌剂对PAHs污染焦化厂土壤进行微生物修复,采用固相微萃取及固相萃取方法提取评价PAHs的生物有效性,分析降解率和生物有效性变化的差异及相关关系.结果表明,该焦化厂土壤中PAHs总量以低环PAH为主,微生物菌剂对土壤总PAHs降解率为68.3%;微生物作用后,孔隙水中PAHs的降低以3、4环为主,孔隙水中PAHs变化率普遍低于土壤中的降解率;Tenax-TA提取降解前后土壤中的PAHs,降解后3、4环PAHs的快速解吸组分降低,5、6环的快速解吸组分变化不大;土壤中PAHs降解量分别与PAHs孔隙水浓度和Tenax-TA快速提取量存在相关关系.以上结果表明可用PAHs孔隙水浓度以及Tenax-TA快速提取量预测微生物对土壤PAHs的降解,这为焦化厂土壤PAHs污染的修复提供了理论依据.

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 PAHs 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.