水生生物对松花江污染物重金属和苯酚脉冲式暴露的响应及生态毒理机制

Traditional standard laboratory toxicity tests performing at constant exposure concentrations have made it possible to study and develop water quality criteria. Yet, such classical methods rather unspecifically investigate the toxicity on time-varying exposures. Due to this limitation, traditional toxicity tests have so far almost exclusively been carried out in assessing the effects of realistic time-varying exposures from measurements made under constant exposure conditions..This research based on time - response approach was designed to characterize the ecotoxicology effects of pulsed exposures of typical pollutant（heavy metal Pb、Cr、Cd、Cu and phenol）in Songhua River on the aquatic sensitivity species, in which the effects of pulsed length (duration), pulsed magnitude (concentration), and the interval (recovery time) between pulses were characterized by static test, static-renewal test, flow-through test and elutriate test..The purpose of this study was to use quantitative survival-time approach employing time-response model based threshold damage test methods to examine latent effect and complete recovery time on a broad suite of endpoints of the aquatic sensitivity species to sequential pulsed and fluctuating typical pollutant concentrations in Songhua River. A second objective of this study was to elucidate tolerance adaptation mechanism for pulsed exposure of heavy metal（Pb、Cr、Cd、Cu）and phenol in aquatic organism and fish using condition factors, and toxicant distribution among organs, and ROS level from oxidative stress, and antioxidant potential, and energy reserves, and metabolic cost of toxicant exposure，and biochemical Hsp70, and immunocytochemical （apoptosis and cell proliferation）responses as biomarkers. The results of this study wish to provide new technical approach and theory foundation in ecotoxicological diagnosis and pollution ecology evaluation for deriving national or local water quality criteria of different chemicals on pulsed exposures for protecting aquatic biota in China.

传统标准的实验室毒性实验迄今为止几乎不能特定地完成现实环境中时间-改变的脉冲式暴露效应评价。本项目以东北地区第二松花江重金属（Pb、Cr、Cd、Cu）和苯酚为目标污染物，选择东北地区河流生态系统不同营养层次不同科属的敏感水生生物（藻、溞、鱼和底栖生物），应用时间反应法开展脉冲长度，脉冲大小，脉冲间隔都在变化的急性、慢性和特定生命阶段的脉冲式暴露效应研究。通过静态试验、静态更新试验、流动试验、淘分试验，检测重金属和苯酚在各种相继脉冲和波动暴露下的延迟效应，定量预测完全恢复时间，阐明敏感水生生物的恢复过程及脉冲式暴露的耐受适应特征。同时，结合脉冲式暴露的动力学过程，检测能量储备、毒物代谢价值、保护蛋白合成，从氧化应激的角度探讨脉冲式暴露细胞凋亡的耐受适应机理。本项研究结果能够为东北区域特征水环境基准制定，有效地提供适宜于脉冲式暴露的生态毒理学理论依据和新的技术途径。

传统标准的实验室毒性实验迄今为止几乎不能特定地完成现实环境中时间-改变的脉冲式暴露效应评价。本项目以东北地区第二松花江典型重金属和苯酚为目标污染物，选择东北地区河流生态系统不同营养层次不同种属的敏感水生生物，采用时间加权平均浓度（TAC）方法实施脉冲长度，脉冲大小，脉冲间隔都在变化的急性、慢性和特定生命阶段的脉冲式暴露效应的评估与预测。通过脉冲暴露的时间-死亡、时间-生长和时间-生殖效应的观测，阐明了敏感水生生物对于单一、多重脉冲暴露的恢复过程及耐受适应特征。研究证实动力学过程中热休克蛋白((HSP70))、小热休克蛋白(sHSP) 的诱导和金属硫蛋白(MT)的合成是生物体脉冲暴露应激响应分子机理的关键标识。在这项研究中，对于每一能量资源分配都需要付出代价的相关胁迫效应，已经以个体的能量收支平衡在分子水平及更高的生物组织水平上显示证明。本项研究结果能够为东北区域特征水环境基准制定，有效地提供适宜于脉冲式暴露的生态毒理学理论依据和新的技术途径。