| The speciation of pollutants can markedly impact the fate and bioavailability of them. Nowadays, the study of the speciation of soil organic pollutants and its influence factors is still in its infancy. This paper postulates a pragmatic speciation scheme for the fractionation of soil polycyclic aromatic hydrocarbons (PAHs) that could correlate with their bioavailabilities, and develops a reliable sequential ultrasonic extraction scheme that could differentiate PAHs into four fractions with different environmental relevance. We also investigated the key fractors to the fraction fistribution of PAHs, including soil properties, PAHs properties, aging time and combined pollutants, as well as the relationship between bioavailability of PAHs and their fractions. The main results of this paper are shown below:(1) Soil PAHs were speciated into water soluble, organic acid soluble, organically bound, and residual fraction via sequential ultrasonic extraction. Isotopic experiment verified the accuracy and relability of the sequential ultrasonic extraction.(2) The key factors influence the fraction distribution of PAHs were investigated. The soil properties, aging time, chemical structure and octanol-water partition coefficient (Kow) of PAHs strongly affect the distribution of PAHs. Different combined pollutants have different impacts on fraction distribution of PAHs. Heavy metal mainly influence the organically bound and residual fractions of PAHs, while cation surfactant mainly influence the water soluble and organic acid soluble fractions.(3) The relationship between bioavailability and speciation of PAHs was revealed. The bioavialiability of PAHs is consistent with the sum of water soluble and organic acid soluble fractions of PAHs, which means these two fractions are the major part of bioavaliabiliry of organic pollutants. |
PDF Full Text Request