澳门南湾湖钻孔沉积物中自由态和束缚态的多环芳烃

研究自然条件下沉积物中有机污染物沉积后的环境行为,考察澳门南湾湖钻孔沉积物中自由态和束缚态PAHs的含量与分布.研究表明,自由态PAHs以4-环、6,7-环和5-环为主,其质量百分贡献分别为28.7%～40.6%、17.6%～29.6%和13.2%～28.2%;而束缚态PAHs则以4-环、3-环和2-环为主,质量百分贡献分别为42.3%～55.8%、20.2%～35.8%和7.8%～18.8%.说明低分子量PAHs比高分子量PAHs更容易进入沉积有机质的孔隙中.自由态PAHs的垂直分布特征受区域经济发展及环境治理进程的影响,束缚态PAHs的含量一方面受控于PAHs的输入量,另一方面与沉积有机质的结构(特别是聚合程度)有关,随着沉积埋藏时间的延长有利于各化合物从自由态向束缚态转变.

Free and Bound PAHs in a Sediment Core from Nam Van Artificial Lake of Macao

To study the posts-depositional behaviors of organic pollutants in natural conditions, concentrations and distributions of free and bound PAHs in a sediment core from Nam Van artificial Lake of Macao were investigated. Result indicate that free PAHs are predominated by 4-ring, 6,7-ring, and 5-ring PAHs, with the mass percentages of 28.7% to approximately 40.6%, 17.6% to approximately 29.6%, and 13.2% to approximately 28.2%, respectively, and for bound PAHs, the main components are 4-ring, 3-ring, and 2-ring ones, with mass percentages 42.3% to approximately 55.8%, 20.2% to approximately 35.8%, and 7.8% to approximately 18.8%, respectively, which suggeste that PAHs with low molecular weight are more prone to entering the micro-pores of sediment organic matters. Vertical profile of free PAHs concentrations in sediment core, to some degree, is correlated with the degree of regional economy development and the proceeding of environmental management. The concentrations of bound PAHs in the sediment core are controlled by the total PAHs mass input to the sediments and the structure (especially the polymerization) of sediment organic mater. The sediment burying favors the transformation of free form to bound form for PAH compounds.