寒区农田系统多环芳烃多界面迁移转化过程模拟与污染风险评估

Polycyclic aromatic hydrocarbons (PAHs) are a kind of ubiquitous and important pollutants in the farmland environment, which have become a research hotspot due to their extensive sources and health hazards. There is insufficient research on complexity feature recognition, spatial-temporal distribution characteristics, relationships between interface transmission and bio-availability, migration and transformation rules and diagnostic techniques of pollution risk of PAHs in farmland in cold region. To solve these issues, complex adaptive system is applied and macro areas are combined with micro interfaces. Through monitoring pollution levels of PAHs in air, snow cover, soil and crop, complexity feature is identified, emission/residue inventory is established, and the spatial-temporal evolvement rules of PAHs in cold region is revealed. Multi-interface transmission and environmental process in farmland in cold region is definite, model of migration and transformation in multi-interface is established, and the migration and transformation rules and heterogeneous characteristics of PAHs are discovered. Data monitoring, numerical simulation and pollution risk assessment methods are coupled, ecology and health risks in farmland in cold region are evaluated, and pollution parameter equations of PAHs are established based on principles of spectrum analysis. Study results have significant academic values and strategic importance for enriching and developing compile techniques of PAHs inventory and theory of geochemical cycle, realizing eco-environmental safety of farmland in cold region and ensuring national food security strategy under the new situation.

多环芳烃（PAHs）是农田环境中普遍存在的一类重要污染物，因其具有来源广泛和健康危害等特点，已成为世界各国的研究热点。针对目前寒区农田系统PAHs复杂性特征识别、界面传输与生物有效性关系和污染风险诊断技术研究不足的现状，本项目将宏观区域与微观界面研究相结合，通过监测大气、积雪、土壤和作物中PAHs的污染水平，识别寒区农田系统PAHs的复杂性特征，建立并绘制PAHs排放/残留清单，揭示PAHs时空演变规律；明确寒区农田系统PAHs多界面传输与环境行为过程，建立PAHs多界面迁移转化模型，揭示PAHs迁移转化规律；耦合监测数据、数值模拟与污染风险评估方法，量化寒区农田系统PAHs生态与健康风险，并建立基于光谱分析原理的PAHs污染参数方程。研究成果对丰富和发展PAHs清单编制技术与地球化学循环过程理论，实现寒区农田系统生态环境安全，确保新形势下国家粮食安全战略需求具有重要的学术价值和战略意义。

多环芳烃（PAHs）作为农田系统普遍存在的持久性有机污染物，因其来源广泛和对人体健康以及粮食生产安全构成的潜在威胁，已成为世界各国关注的热点。但有关高寒地区农田系统PAHs复杂性特征识别、界面传输及其与生物有效性关系的研究仍存在不足，并且亟需建立农田系统PAHs污染风险诊断技术，以满足新形势下国家粮食安全与生态环境安全战略需要。本研究以土壤、植物、大气和积雪等环境介质为研究载体，动态监测了农田土壤长时间序列PAHs时空分布与演变规律，揭示了PAHs来源构成的复杂性特征。模拟验证了持久性有机污染物的初次分馏效应和二次分馏效应，并揭示了受温度与土壤有机质双重影响的污染物排放/残留格局；识别了高寒地区典型城市新降雪PAHs的污染特征、可能来源及沉降通量，并突破了以往定位观测的局限性，提出了以新降雪为环境监测介质的区域大气环境监测网络优化布局；首次利用火点数据，识别了我国东北地区秸秆露天焚烧PAHs、PM10、PM2.5、CO、NOx等污染物排放通量，为区域大气环境污染防治和秸秆焚烧控制与管理提供了科学依据；同时，以植物为中心，建立了土壤-大气双通道污染物作物吸收模型，揭示了植物吸收有机污染物的主要路径，并通过大田实验探寻了作物体内PAHs的差异化富集特征。此外，本项目有力拓展了对农田-河沼系统污染物环境行为与生态风险的系统性研究，建立了农业面源污染负荷估算模型，并对农业面源污染进行了全过程跟踪模拟与调控，解决了缺资料地区农业面源污染数值模拟技术难题，并揭示了主控污染因子。识别了农业流域水环境重金属、农药与常规水质指标的污染特征与潜在生态风险，构建了基于食物链结构组成的重点保护物种污染物暴露风险评估模型，并明确了污染物暴露剂量-效应关系，推动了农业生产与区域水生态安全的协同保障，为丰富污染物地球化学循环过程理论和保障生态环境安全提供了技术支撑。