长江重庆段两江水相、间隙水和沉积物中邻苯二甲酸酯的分布与分配

对长江重庆段两江水相、间隙水和沉积相中5种邻苯二甲酸酯(PAEs)的分布与分配进行了研究.结果显示水相中PAEs含量为53.2 ～343.0 ng·L-1,间隙水中为916.8～7517.1 ng·L-1,沉积相为1787.0 ～5045.9 ng·g-1,间隙水相PAEs含量高于水相；比较两江PAEs分布,支流嘉陵江污染程度高于长江干流；邻苯二甲酸二丁酯(DBP)和邻苯二甲酸双(2-乙基己基)酯(DEHP)是水体和沉积物中的主要污染物,在间隙水相存在明显富集,这两种污染物在水相中的含量低于地表水质量标准；黏土是影响沉积相中PAEs分布的重要因素,有机质含量对其影响较小；沉积物-间隙水间的lgKoc值与lgKow不相关,DBP在沉积物和间隙水间的分配接近平衡,邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)有由沉积相向间隙水相迁移的趋势,DEHP则由间隙水相向沉积相迁移.与国内外其他地区相比,研究区PAEs含量处于中等偏下水平.

Distribution and partition of phthalate esters in water phase, pore water and sediments from Chongqing section of the Yangtze River

The distribution and partition characteristics of five phthalate esters (PAEs) in water phase, pore water and sediment from Chongqing Section of the Yangtze River were investigated. The total PAE concentration ranged from 53.2 to 343.0 ng·L^-1 in water phase, from 916.8 to 7517.1 ng·L^-1 in pore water and from 1787.0 to 5045.9 ng·g^-1 in sediments. PAEs concentration in pore water was much higher than that in the water phase. Generally, PAE pollution in Jialing tributary was more serious than that in the Yangtze mainstream. DBP and DEHP were the main pollutants in water column and sediments, and they were obviously enriched in pore water. Concentrations of DBP and DEHP in water phase were both lower than the China Environmental Quality Standards for surface water. Clay content in sediments was the primary factor affecting PAEs distribution while organic matter content had less effect. Results of PAEs partition between sediment solid phase and pore water phase showed that there was no correlation between lgK_oc and lgK_ow of PAEs. When the partitioning of DBP concentration between measured sediment and the surrounding pore water tended to be close to equilibrium, DMP and DEP both had strong trends from sediment to pore water phase and the opposite tendency was significant for DEHP. As compared to the results from other studies, the PAE concentrations of the study region were in a low-to-medium level.