地表覆盖变化对典型持久性有机污染物归趋行为影响及模型模拟

Simulating the distribution and fate of Persistent Organic Pollutants (POPs) using a spatially environmental multimedia fate model in the regional scale is one of the hot spot of present research and also an essential step in environmental risk assessment. However, the research of POPs fates in environmental medias between urban and rural area has many insufficiencies, especially in regional scale of urban agglomeration area. This project plans to improve multi-media environment BETR model based on land cover data, which will distinguish the pollutants fate between urban and rural multi-media coupled with land cover information. The multi-media fates of POPs model based on land cover changes for urban agglomerations regional scale will be established in Bohai Rim. The reliability of model results will be assessed through comparison between the measured and modeled concentrations, sensitivity analysis and uncertainty analysis, and scale effects also will be conducted to verify the scale adaptation of model. Through simulating pollutants fates of seasonal variations in multi-media and predicting dynamic trends, the relationships between land cover changes and multi-media fates of POPs will be studied. POPs transfer laws between urban and rural area through steady and unsteady simulation also will be researched in regional-scale. Improved model lays a good foundation method for studying POPs fates between urban and rural area in the urban agglomerations regional scale and for providing strong supports for POPs environmental risk assessment in regional scale.

区域尺度持久性有机污染物(POPs)在环境多介质中迁移扩散过程及其模拟是当前国际研究热点问题之一，但在不同土地覆盖变化条件下研究污染物在城市-农村多介质归趋方面还不完善。本项目拟基于土地覆被数据，研究反映城市农村土地格局对污染物扩散过程的模型框架，探讨用以区分城市和农村多介质污染物扩散模拟方法。在黄渤海区域，建立基于地表覆盖的适合城市群区域尺度的POPs多介质迁移模型，以典型POPs多环芳烃为例，探讨改进模型针对区域污染物多介质扩散的参数敏感性和不确定性，并评估模型尺度效应。模拟预测季节性变化对污染物多介质扩散的影响及其动态趋势，揭示土地覆被变化与POPs多介质空间耦合关系，剖析区域尺度城市与郊区污染物多介质稳态和非稳态的迁移规律，从而为研究城市群区域尺度污染物在多介质迁移规律打下良好方法基础，并为研究区域POPs生态风险评估和控制提供强有力的数据支撑。

区域尺度持久性有机污染物在环境多介质中迁移扩散过程模拟是当前国际研究热点问题之一，本项目针对典型POPs污染物在区域尺度城市-农村传输难以精确模拟的问题，构建了区域尺度城乡环境多介质模型(BETR-Urban-Rural)，该模型重构了BETR模型网格划分、多介质传输等模拟过程，新增城市和农村模块及稳态及动态模拟算法，使其能够在大尺度网格划分条件下模拟城乡多介质传输通量，克服了传统逸度模型在区域尺度上难以精确模拟城市-农村传输过程，验证结果显示Bap模拟浓度与实测浓度的平均相对误差的绝对值由原模型的37%降低到3%，并研究了改进模型针对区域污染物（PAHs、PFOA等）多介质扩散的参数敏感性和不确定性。基于该模型模拟分析了典型污染物（PAHs、PFAAs等）高排放对“水-土-气-生”多介质的综合影响，研究了土地利用变化及气候变化条件下稳态和非稳态条件下典型污染物城乡传输通量，结果显示在未来土地利用变化和气候变化的影响下，未来PFOS在淡水和城市土壤中的浓度呈现下降趋势，会降低淡水和城市土壤中生物的暴露风险，造成这种现象的主导因素是未来温度、降水和城市化速率的增加，而海水和农村土壤中PFOS的浓度则表现出上升趋势，这将会给海洋生态带来不利影响。然而在减排政策和气候变化的共同影响下，各介质中PFOS的浓度都会大大降低，从而降低PFOS对生态系统的风险。另外基于逸度模型和点源扩散模型，研究了黄渤海区域尺度持久性污染物城市-郊区梯度关系，并以非故意排放PCBs(UP-PCBs)为例，定量模拟了IP-PCBs和UP-PCBs的城乡梯度、空间来源、单体的时间来源及行业来源等，拓展了模型在城乡梯度解析与定量溯源的应用范围。.相关成果在Environmental Pollution、Science of the Total Environment、Journal of Environmental Sciences等国内外著名刊物上发表7篇（SCI收录5篇），研发的模型应用于天津水源地污染物迁移模拟的项目中，作为主要执笔人撰写的政策咨询报告被地方环保部门所采纳。