从天津市北塘河口沉积物提取了天然溶解性有机质(dissolved organic matter,DOM),利用荧光淬灭法测定了芘与所得DOM的结合系数KDOM,并研究了不同离子强度及离子类型对KDOM的影响.结果表明,DOM对芘的KDOM为1.27×105L·kg-1,远高于固态有机质的吸附能力,说明DOM对多环芳烃等憎水性有机污染物在水环境中的归趋具有不可忽视的影响.随着阳离子浓度的增加,芘的KDOM呈现先降低,再升高,然后稳定在某一值的复杂变化趋势.不同阳离子对芘的KDOM具有不同的影响,而所研究阴离子对KDOM影响不大。
Natural dissolved organic matter(DOM) was extracted from the sediment of the Beitang Estuary,Tianjin,China.DOM/water partition coefficients for pyrene(KDOM) were measured using fluorescence quenching method.The impacts of ionic strength and ion types on KDOM was studied and discussed.The results showed that KDOM of pyrene was 1.27 × 105L·kg-1,and the binding capacity of DOM was much stronger than solid organic matters.Accordingly,DOM can not be ignored factor affecting the fate of hydrophobic organic contaminants such as PAHs in aqueous environment.With increasing concentration of cationic ions,KDOM of pyrene showed a complex pattern of increasing initially,then decreasing,and finally stabilizing at a plateau.Different cationic ions had varied impacts on KDOM of pyrene,while the tested anionic ions did not show significant influence.