[Aging Law of PAHs in Contaminated Soil and Their Enrichment in Earthworms Characterized by Chemical Extraction...

To evaluate the effect of aging on the availability of PAHs, chemical extraction by exhaustive ( ASE extraction) and nonexhaustive techniques (Tenax-TA extraction, hydroxypropyl-p-cyclodextrin ( HPCD ) extraction, n-butyl alcohol ( BuOH) extraction) as well as PAHs accumulation in earthworms (Eisenia fetida) were conducted in yellow soil from Baguazhou, Nanjing, China, and red soil from Hainan, China, spiked with phenanthrene, pryene and benzo(a) pyrene and aged 0, 7, 15, 30 and 60 days. The results showed that the concentration of PAHs extracted by ASE and three nonexhaustive techniques and accumulated by earthworms significantly decreased with aging time, except the ASE extracted concentration between 30-and 60-day aging time. Furthermore, the relationships were studied in this experiment between chemical extracted PAHs concentration and accumulated concentration in earthworms. PAHs accumulated concentration in earthworms was not significantly correlated with the exhaustive extracted concentration of PAHs in soil (R² 0.44-0.56), which indicated that ASE extraction techniques could not predict PAHs bioavailability to earthworms because it overestimated the risk of PAHs. However, the PAHs accumulated concentration in earthworms was significantly correlated with the three nonexhaustive extracted concentrations of PAHs in soil, which indicated that all the three nonexhaustive techniques could predict PAHs bioavailability to earthworm to some extent, among which, HPCD extraction (R² 0.94-0.99) was better than Tenax-TA extraction (R² 0.62-0.87) and BuOH extraction (R² 0.69-0.94). So HPCD extraction was a more appropriate and reliable technique to predict bioavailability of PAHs in soil.