典型河流-河口-近海系统中多相态有机磷酸酯的赋存特征及分配机制研究

With the accelerated progress of the halogen-free flame retardants, more and more organophosphate esters (OPEs) have entered into the environment. However, information on the occurrence, migration, transformation and fate, and ecological risks of multi-phase OPEs in the aquatic environment is little, especially in China, a leading global producer and potential consumer of OPEs. In this study, frequently-used OPEs will be measured in surface water and sediments from the typical river-estuary-sea system. The aims are to 1) investigate the occurrence, distribution characteristics, the differences in composition, and spatial-temporal trends of OPEs in the apparently dissolved and particulate states of surface water and the sediments from the typical river-estuary-sea systems; 2) cite the prediction model of the partition coefficient between carbon black and water of organic pollutants, analyze quantitatively the migration trendency of OPEs between particulate matter and water, and find out the controlling factors affecting the migration trendency; 3) explore the characteristics of multi-phase OPEs in overlying water during the processes of resuspension, burial, and so on. This study has important scientific significance to reveal the occurrence characteristic and distribution mechanism of multi-phase OPEs in the aquatic environment and assess accurately the ecological risks of OPEs.

阻燃无卤化进程的加速，越来越多的有机磷酸酯（OPEs）进入环境，但目前，对水环境多相体系中OPEs的赋存、迁移转化和归趋及生态风险等仍知之甚少，尤其是我国，作为OPEs阻燃剂的生产大国和潜在的使用大国，相关研究尤为薄弱。本项目拟以典型河流-河口-近海系统为研究区域，以常用的OPEs为目标物，考察沉积物和水体中悬浮颗粒态、表观溶解态等多相态OPEs的赋存特征、组成成分差异及其时空异质性；量化分析不同OPEs同族体在颗粒物和水相间的迁移趋势，找出控制其迁移趋势的关键因素；探究沉积物再悬浮、埋藏等释放过程中，上覆水中悬浮颗粒态、表观溶解态等多相态OPEs的变化特征。本项目对揭示水环境中多相态OPEs的赋存特征和分配机制及准确评估OPEs的生态风险具有重要的科学意义。

本项目旨在探讨大辽河-河口-近岸环境水体和沉积物中有机磷酸酯（OPEs）的浓度水平、组成特征、时空差异及分配规律等。水体中OPEs浓度自上而下向靠近城区的方向，整体呈上升趋势。OPEs与盐度之间普遍呈显著负相关性（p＜0.01），可以推断，海水对水体中的OPEs具有一定的稀释作用。磷酸三（2-氯乙基）酯和磷酸三乙酯是水体中主要的OPEs同族体。在枯水期，除磷酸三辛酯具有强变异性外，水体中其他表观溶解态和自由溶解态OPEs同族体浓度均具有中等变异性。在丰水期，磷酸三辛酯、磷酸三间甲苯酯和磷酸（2-乙基）己基二苯酯均具有强变异性，其他OPEs同族体具有中等变异性。无论是在枯水期还是在丰水期，OPEs在悬浮颗粒物-水界面的logKp和logKoc普遍与＜4 μm颗粒物的百分含量呈正相关性，而与4-8 μm和＞8 μm颗粒物的百分含量负相关。OPEs同族体（磷酸三异丙酯除外）在沉积物-水界面的logKoc与4-8 μm和＞8 μm颗粒物的百分含量均负相关，这一规律与OPEs同族体在不同粒径悬浮颗粒物中的分布规律是一致的。在枯水期，三苯基氧化膦具有从水体向沉积物扩散的趋势，其他OPEs同族体均具有从沉积物向水体扩散的趋势。在丰水期，OPEs同族体的逸度分数均小于0.5，说明它们均具有从水体向沉积物迁移的趋势。PCA-MLR、PMF和Unmix三种模型均较好地预测了渤海35条主要入海河流中OPEs的空间演变趋势。PCA-MLR在解析的过程中，出现了负值。Unmix模型对三种主要OPEs同族体的拟合较差。PMF法对OPEs的拟合效果优于PCA-MLR法和Unmix模型。因此，PMF法被认为是本研究中OPEs源解析的首选模型。磷酸三乙酯、磷酸三丁酯、磷酸三（2-氯乙基）酯和磷酸三（2-氯丙基）酯的危害指数的最大值小于0.004，说明它们对渤海生态系统造成的联合生态风险可以忽略不计。