基于水生态毒理过程的环境风险评价模型研究

Aquatic ecological risk assessment has become an emerging point in the development of the water environmental science. This research aims to present an ecological risk assessment model based on water ecotoxicological process to predict the fate of pollutants in the water environment and its impact on the aquatic ecosystem via a method of coupling of ecotoxicology and environmental hydraulics. First, a two-dimensional water environment model is constructed to simulate the transformation process of pollutants in the water, accordingly a concentration field simulation result is available.Second, the space grid aggregation and the time step coupled method is employed to couple the simulation results and an water ecotoxicological model aquatox to overcome the model's inherent defects, which means the model neglect spatial heterogeneity and is essentially a static box model. Third, two risk characterization methods, namely acute and long-term, are proposed to express the level of ecological risk quantitatively. Finally, the dynamic temporal-spatial aquatic ecosystems risk assessment method and model are established, which can be used to represent the combined environment fate and effects of conventional pollutants, such as nutrients and sediments and toxic chemicals in aquatic ecosystems, and the transfer of biomass, energy and chemicals from one compartment of the ecosystems to another are presented by two risk characterization methods to quantitatively indicate the level of ecological risk. Basic theories and methodologies of hydraulics, biology, ecology and toxicology are utilized to achieve the multidisciplinary in this research. A combination of the control experiments, field monitoring, data analysis and mathematical modeling is employed in the Yangtze Delta region as a case study to perform reliability analysis of the model.

水生态风险动态评价是水环境科学发展的热点。本研究拟耦合生态毒理学和环境水力学，研究污染物在水环境中的归宿及相应的生态风险。首先建立二维水环境模型,模拟污染物在水体中的迁移转化过程，获得污染物动态浓度场；研究空间-过程耦合的生态风险评价模型,采用空间网格聚集和时间步长耦合技术，实现空间动态浓度场与水生态毒理模型AQUATOX耦合，克服该模型缺乏空间分布和时间动态的缺点；建立河湖水生态风险时空动态评价方法和模型，实现水生态系统急性和长期两种风险动态模拟。研究中将采用水力学，生物学、生态学和毒理学的基本理论与方法，实现多学科交叉。研究以长江口区域为对象，通过控制实验、野外监测、数值模拟，分析长江口未来3年生态风险变化趋势，并分析模型可靠性。

研究污染物在水环境中的归宿及其对水生态的影响，建立水生态风险动态评价方法是水环境科学发展的新兴点，目前国内外都处于起步摸索阶段。常规生态风险评价方法采用单物种外推或中宇宙模拟,不能从生态系统的角度评价水污染对整体生态系统的影响。以种群或生态系统为基础的生态风险模型法的出现，使得生态风险评价由单纯依靠生态毒理学实验工具向毒理学和模型模拟相结合转化。采用数值模拟方法,耦合生态毒理学和环境水力学模型来建立生态风险评价是一个有益的尝试.本项目首先建立二维水环境模型,模拟污染物在水体中的迁移转化过程，获得污染物动态浓度场；研究空间-过程耦合的生态风险评价模型,采用空间网格聚集和时间步长耦合技术，实现空间动态浓度场与水生态毒理模型AQUATOX耦合，克服该模型缺乏空间分布和时间动态的缺点；建立急性和长期两种风险表征方法;最终建立河湖水生态风险时空动态评价方法和模型。该模型可以模拟污染物进入水体后在多介质中的浓度变化以及各物种存活性和生物量变化，定量表征风险高低。可以为水环境污染事故应急、水环境修复提供技术手段。