滇池沉积物中多环芳烃赋存状态及其再分配的初步研究

A Primary Investigation on the Occurrence and Redistribution of Polycyclic Aromatic Hydrocarbons in Sediments from Dianchi Lake,Southwest China

利用索氏抽提、Tenax部分萃取和沉积物的粒度和密度分离等方法对滇池沉积物中多环芳烃(PAHs)的赋存状态及其再分配进行了研究。研究结果表明:滇池沉积物中PAHs主要存在于小粒度和低密度的组分中;尽管PAHs在粒度分布上存在一定的差异,但沉积物中碳质吸附剂的组成和含量才是决定PAHs在沉积物中赋存状态的主要因素;由于PAHs与沉积物中不同吸附剂相互作用的差异,随着时间的推移,沉积物中的PAHs存在一个再分配过程,吸附在无定形有机质和无机矿物等弱吸附剂上的PAHs逐渐向黑炭、焦炭等碳质吸附剂上转移,导致沉积物中的PAHs慢慢被锁定,因而其生物有效性也逐渐下降。

The Soxhlet and Tenax extraction methods, together with the size and density separation of lake sediments, were used for investigations on the occurrence and redistribution of polycyclic aromatic hydrocarbons （PAHs） in sediments from the Dianchi Lake, Southwest China. The results suggested that PAHs in sediments from the Dianchi Lake primarily occurred in the fractions which are small in particle size and low in density. Although there exists some difference in size distribution of PAHs in sediments, the composition and content of carbonaceous sorbents are the main causes influencing the occurrence of PAHs in sediments. Due to the different interactions of PAHs with different geosorbents, PAHs in sediments would be redistributed as the depositional time increased. That is, PAHs adsorbed on weak sorbents, such as amorphous organic matter and/or inorganic minerals, would be gradually transferred to carbonaceous sorbents, such as black carbon and coke. Therefore, PAHs in sedi- ments would be sequestrated slowly and their bioavailability could decrease gradually.