多泥沙河流中内分泌干扰物在底栖贝类体内的生物富集和毒性效应研究

Recently, the organic pollution in the Yellow River catchment gradually deteriorated. Among the various emerging organic contaminants, much attention has been paid to endocrine disrupting chemicals (EDCs) due to its damage to the functions of the reproductive and endocrine systems in aquatic organisms. The Yellow river is characteristic of high sediment concentrations, which renders it peculiar physic-chemical properties, while sediments provide important habitats and food sources for benthic mollusks. In the present study, comprehensive sampling and analyses of water, suspended sediment, sediment and mollusks samples in the river catchment were integrated with the laboratory ecological experiment simulating water-suspended sediment-mollusks systems, taking the widespread Corbicula fluminea and Bellamya aeruginosa as the representative mollusks. The objective is to reveal the spatial-temporal distribution of EDCs in the complex water-suspended sediment-sediment-mollusks systems and their interactions, and the effects of composition and concentrations of suspended sediment on the bioconcentration of EDCs. Moreover, through the measurement of toxicity endpoints for estrogenic effects induced by EDCs in mollusks, the exposure-dose-response relationship of EDCs in the presence of suspended sediments will be elucidated. The results will provide theoretical references for the assessment of water quality and ecological risks, the screening of water quality criteria and effective control of water pollution in rivers with high sediment concentrations.

近年来，黄河流域水体有机污染日益严重，其中内分泌干扰物因其对水生生物生殖系统功能的毒性作用而备受关注。黄河流域水少沙多，具有不同于其他河流体系的理化特性，而泥沙为底栖贝类提供重要的栖息地和食物来源。本研究针对黄河高含沙量的特性，以河蚬（Corbicula fluminea）和铜锈环棱螺（Bellamya aeruginosa）为代表性贝类，通过流域综合系统的采样分析和模拟水生态微域的控制实验，揭示内分泌干扰物在水体-悬浮颗粒物-沉积物-贝类四相共存的复杂体系中的时空分布规律及其耦合作用机理，考察悬浮颗粒物组成和含量对内分泌干扰物在贝类体内生物富集的影响规律及其作用机制，同时通过雌激素效应毒理指标的测定，阐明悬浮颗粒物存在条件下内分泌干扰物的环境暴露浓度-贝类体内剂量-生物毒性效应之间的响应机制，为多泥沙河流的水质评价、水质基准的建立和水污染控制提供科学依据。

随着经济的快速发展以及生活污水、农业和工业废水的排放，具有高含沙量的黄河受到了严重的有机污染，其中内分泌干扰物因其对水生生物生殖系统功能的毒性作用而备受关注。本研究结合了流域综合系统的采样分析和模拟水生态微域的控制实验，其中实地采样在黄河干、支流采集水、沉积物和悬浮颗粒物样品，检测三相中全氟化合物（PFCs）、邻苯二甲酸酯（PAEs）、有机氯农药（OCPs）、多氯联苯（PCBs）、多溴联苯醚（PBDEs）等内分泌干扰物的浓度，对其在三种环境介质中的分布特征和影响因素，以及其对水生生物的生态风险进行评估，结果表明：常规水质指标、沉积物和悬浮颗粒物的理化性质会影响污染物在水体、沉积物和悬浮颗粒物中的浓度水平；众多污染物中，黄河流域受到PBDEs污染产生的生态风险最高，受PFCs污染产生的生态风险较低，但PFCs中全氟辛烷磺酸（PFOS）产生的生态风险不容忽视；此外，悬浮颗粒物的存在加大了污染物对水生生物的风险性。基于实地采样的研究结果，控制实验针对黄河高含沙量的特性，以河蚬（Corbicula fluminea）为代表性水生生物，建立模拟水体-悬浮颗粒物-贝类水生态微域的实验体系，通过测定贝类体内PFOS的生物富集量及包括虹吸行为、抗氧化防御系统活性、相关基因表达水平、组织病变等在内的一系列毒性指标，研究悬浮颗粒物对PFOS的生物富集和毒性效应的影响，结果表明：悬浮颗粒物通过增加PFOS对河蚬的毒性而影响到生物富集与毒性效应之间的正响应。综上所述，本项目揭示了多泥沙河流中内分泌干扰物在水-悬浮颗粒物-沉积物三相共存的复杂体系中的时空分布规律及其耦合作用机理，阐明了内分泌干扰物的生物富集和毒性效应之间的响应机制，充分说明了悬浮颗粒物的存在加大了污染物对水生生物的毒性，为多泥沙河流的水质评价、水质基准的建立和水污染控制提供了科学依据。