沉积物是水体污染物的源和汇，与整个生态系统及人类健康有着密切的联系。沉积物毒性的科学准确评估，无论是对环保部门制定污染沉积物管理和综合治理对策，还是对污染沉积物修复与处理处置工程的设计都是极其重要和必要的。以往沉积物毒性表征研究多采用简单便捷的生物存活实验针对造成急性致死效应的沉积物开展。然而，随着环境的逐步改善，造成急性毒性的天然沉积物逐渐减少，沉积物毒性表征变得日益具有挑战性。针对环境中未造成水生生物急性死亡但是对水生生物产生健康损害的非极毒沉积物，常规的以死亡率为单一测试指标的沉积物毒性实验无法满足此类沉积物的毒性表征要求。因此，探究包括生物标志物在内的多指标联合评估对于非极毒沉积物毒性表征的适用性变得尤为重要。 为此，本研究以河蚬为受试生物，采用文献大数据解析，初步筛选出一套适用于非极毒沉积物毒性表征的河蚬测试指标，并在此基础上，以典型城市纳污河流为研究区，在确认该河流未产生急性毒性前提下利用大数据初筛指标进行沉积物初始毒性表征，确认此类河流开展毒性评估的必要性。在此基础上，以抗生素为典型模式污染物，开展室内模拟实验，阐明不同抗生素在多种基质影响下对河蚬的毒性效应，验证初筛指标体系对于在环境浓度下非极毒污染物毒性表征适用性，最终利用验证后的河蚬指标体系表征城市纳污河流天然沉积物致毒物种类，优化提出适用于非极毒沉积物毒性表征的河蚬指标体系。主要研究结果如下： 1、文献大数据解析结果表明，河蚬具有多种应用于生态毒理学研究优势，是一种合适的污染物毒性研究受试生物。同时，河蚬的生物毒性效应研究多偏重于重金属污染水体，对有机污染物研究相对较少且多局限于持久性有机污染物，对于抗生素类新型污染物的研究尚处于起步阶段，且研究中多采用水相进行模拟实验，对于全沉积物的研究较少。最终，依据沉积物毒性表征需求，结合河蚬在生物毒理学研究中的各类指标特征，在满足全面毒性表征要求的前提下，遵循快速准确的原则，初步筛选出一套适用于河蚬沉积物毒性表征的指标体系，包括行为学指标（掘穴率、虹吸率）、形态学指标（消化腺组织切片观察）、抗氧化防御系统生化指标（SOD、CAT、MDA、GSH、GSH-Px、GR、GST）。 2、针对典型城市纳污河流水体沉积物开展急性毒性筛查与初始毒性解析，首先，河流污染物特征背景调查发现，所测八种目标抗生素在典型城市纳污河流-凉水河水体及沉积物中均有较高的检出率；沉积物中土霉素与环丙沙星含量显著高于其他目标抗生素；水体与沉积物中，污水处理厂下游点位抗生素总浓度均显著升高，主要归因于市政污水处理厂排水。其次，以河蚬死亡率为测试指标开展的研究区各点位沉积物急性毒性筛查发现，该河流各点位沉积物未对河虾产生急性致死效应。在此基础上，利用初筛河蚬指标体系对该河流污水处理厂下游典型点位沉积物开展的初始毒性表征发现，该河流沉积物对河蚬行为能力、消化腺细胞结构、抗氧化因子均产生显著影响，表明该城市纳污河流沉积物开展毒性表征研究必要性较强。 3、不同基质影响下抗生素对河蚬的毒性效应研究表明，典型模式污染物土霉素与环丙沙星对河蚬掘穴和虹吸行为均有显著影响，且其毒性与剂量有关，不同基质影响下河蚬掘穴与虹吸效率具有明显差异；两种药物在不同基质实验组中均对河蚬消化腺细胞结构产生不良影响，不同基质实验组间河蚬消化腺细胞形态结构变化趋势几乎一致。两种药物均对抗氧化防御系统生化指标产生显著影响，且表现出较好的剂量效应关系。同时，各生化指标在配合完成河蚬体内解毒代谢的过程中表现出良好的相关关系。整体上，河蚬行为学指标对抗生素类药物在不同沉积物类型中均有较好的表征能力。消化腺细胞结构变化可以有效的表征抗生素类药物的毒性影响，但在不同基质中无显著差异。鳃组织与内脏团中抗氧化防御系统生化指标对不同基质中抗生素的毒性效应都有很好的表征能力，表现出较好的剂量效应关系。初筛河蚬指标体系能很好的表征城市纳污河流中典型污染物的毒性效应，该指标体系在典型城市纳污河流毒性表征中有较好的适用性。 4、致毒物种类表征结果表明典型城市纳污河流沉积物同时存在氨、重金属及有机物污染；行为学指标中掘穴率指标不够敏感，仅表征出该地有重金属污染，而虹吸率指标可以作为表征沉积物毒性的推荐指标，对三种污染物的表征均有效；消化腺细胞结构观察表征出该地有氨、重金属及有机物污染，形态学观察能较清晰的表征沉积物致毒物类型。河蚬生化指标表征具有较好的敏感性，河蚬鳃组织表征结果得出，该地有重金属及有机物污染；通过河蚬内脏团表征得出，该地同时有氨、重金属、有机物污染。河蚬鳃组织中GSH、MDA、GPx、GST这四种指标推荐用于表征重金属毒性；GST与CAT两种指标推荐用于表征有机物污染毒性。而河蚬内脏团中对于氨、重金属、有机物的毒性表征均推荐使用GPx活性与MDA含量指标。

As the sink and source of the pollutants in the aquatic environment, sediments are closely related to the entire ecosystem and human health. The establishment of a scientific and accurate assessment system for sediment toxicity is necessary for environmental protection departments to formulate the management, as well as to design remediation, treatment and disposal projects for contaminated sediment. Previous studies on sediment toxicity characterization have always been focused on the acute toxicity experiment, which are basically the survival test of organism. With the improvement of the environment, however, acute toxicity caused by natural sediments is gradually reduced, and the characterization of sediment toxicity is becoming increasingly challenging. Conventional sediment toxicity tests based on mortality cannot meet the requirements of toxicity characterization for the so-called non-highly toxic sediments, which are defined as the one that do not cause acute death of aquatic organisms but do harm to aquatic organisms. Therefore, it is essential to explore the applicability of multi-index test to characterize the toxicity of non-highly toxic sediments. Therefore, some work has been done to address the issue in this study. Firstly, we screened out an index system of Corbicula fluminea based on the recent 40 years' research results concerning biological toxicity response to pollutants. Then, taking a typical urban polluted river (Liangshui River in Beijing, China) as the research area, field sampling and laboratory analysis were combined to explore the background pollution characteristics of antibiotics in this river. Meanwhile, the acute toxicity screening was carried out with the mortality of Corbicula fluminea. Then used the preliminary screening index system to do the initial toxicity tests to verify that the sediment from urban river receiving wastewater treatment plant effluent is toxic. On this base, the toxicity test of antibiotics to Corbicula fluminea in different sediment was carried out to demonstrate the applicability of the screening index system to antibiotics toxicity characterize. Finally, the verified index system was used to characterize the toxicity of actual representative sediment from the urban polluted river. At the same time, an index system suitable for non toxic sediment toxicity characterization is proposed. The results are as follows: 1. According to the reviewed literatures, Corbicula fluminea is a suitable organism in toxicity characterization of sediment pollution, given its multiple research advantages in ecotoxicity application. However, the toxicity evaluation by this clam was more focused on the water body polluted by heavy metal. In the limited existing studies on pollution by organic contaminates, most are concerning traditional persistent organic compounds, compared to the little reports on emerging contaminants (eg., antibiotics). Furthermore, water phase simulation experiments are mostly used in the research, the study on the whole sediment is still in its infancy. Finally, according to the requirement of sediment toxicity characterization, combined with the characteristics of various indicators of Corbicula fluminea in biotoxicology research and follow the principle of fast and accurate, a set of indicators suitable for sediment toxicity characterization of Corbicula fluminea was initially screened out. The index system consist of behavioral indexes (siphoning, burrowing ability), morphological observations (histological section observation of digestive gland), and biochemical indicators of antioxidant defense system (SOD、CAT、GSH-Px、GR、GST、GSH and MDA). 2. According to the pollution investigation in Liangshui river, the eight target antibiotics showed high detection rate in both water and sediments; The concentrations of oxytetracycline and ciprofloxacin in the sediments were obviously higher than that of other antibiotics; The antibiotics in Liangshui river were mainly from the discharge of the municipal wastewater treatment plant. Meanwhile, the acute toxicity screening based on the mortality of Corbicula fluminea demonstrated that no acute toxicity was found in the sediments of each site, the preliminary screening index system have shown the significant effects of sediments on the behavior ability, digestive gland cell structure and antioxidant factors of the test organism, demonstrating the great necessity of research on toxicity characterization of sediment in municipal-sewage-receiving river. 3. Concerning the toxic effects of antibiotics on Corbicula fluminea under different substrates, burrowing ability and siphoning behavior of Corbicula fluminea were significantly affected by oxytetracycline and ciprofloxacin, with the effects showing a good dose-effect relationship. Meanwhile, the burrowing and siphon rate of this clam are significantly different depending on different substrates. Both drugs had adverse effects on the structure of digestive gland cells of Corbicula fluminea in different matrix of experimental groups, with the consistent changing trend which is independent on substrates. Obvious effects were also detected on biochemical indicators of antioxidant defense system in Corbicula fluminea when exposed to oxytetracycline and ciprofloxacin, showing a good dose-effect relationship. At the same time, the biochemical indicators were well correlated to each other in the process of completing detoxification metabolism in this clam. In summary, the behavioral indexes and the changes of digestive gland cell structure of Corbicula fluminea have shown good characterization ability on the toxicity of antibiotics in different sediment types. Moreover, the dose-response toxicity of antibiotics in different matrices could be well characterized by the biochemical indexes of antioxidant defense system in gill tissue and visceral mass. Overall, those results demonstrated that the primary screening index system could perform well in characterizing the toxic effects of typical pollutants in urban sewage-containing rivers, verifying the applicability of this indicator system in municipal-sewage-receiving rivers. 4. The results of toxicological species characterization showed the occurrences of ammonia, heavy metals and organic pollutants in the sediments of typical urban sewage-receiving rivers. Compared to the burrow rate, which was not sensitive enough among the testing behavioral indicators and could only indicate the pollution of heavy metals, the siphon rate indicators were more recommended to characterize the toxicity of sediments since they were effective for up to three target types of pollutants. Morphological observation of digestive gland slices showed that there were ammonia, heavy metals and organic pollutants in this area. Morphological observation could clearly distinguish the types of toxic substances in sediments. Biochemical indicators of Corbicula fluminea showed good sensitivity. Gill tissue characterization of Corbicula fluminea showed the contamination of heavy metals and organic pollutants in this area and the characterization of the visceral mass of this clam demonstrated that the sediment was contaminated by all those three types of pollutants. Four indexes (GSH, MDA, GPx and GST) and other two indicators (GST and CAT) in the gill tissues of Corbicula fluminea were recommended to characterize the toxicity of heavy metals and organic pollutants, respectively. Finally, it was recommended to use GPx activity and MDA content in the visceral mass of Corbicula fluminea to illustrate the toxicity features of all those three types of pollutants.