基于化学、毒理和生态“三位一体”(Triad)法研究流域不同土地利用重金属污染土壤的生态风险及其影响

“三位一体”（Triad）法是一种基于化学、毒理、生态三方证据权重的生态风险评价新方法，目前正被西方发达国家开发运用于土壤污染的生态风险评价。本研究将以洋河流域为例，在流域尺度上以上、中、下游不同土地利用类型重金属污染程度不同的土壤及其对应生态系统为研究对象，开展污染土壤的化学分析、室内不同营养级生物的成组暴露实验和野外生态系统调查。基于“三位一体”法综合评价流域不同土地利用类型重金属污染土壤的生态风险，利用地统计学方法和GIS技术揭示流域重金属污染土壤生态风险的空间分布格局。通过流域不同利用类型土壤重金属全量、生物有效性、土壤理化性质与不同营养级生物的毒性和生态系统结构和功能的变化以及综合生态风险表征数据的统计分析，揭示流域重金属污染土壤的生态风险的影响机制，为土壤重金属污染修复与管理提供理论依据，开拓和发展我国景观生态毒理学和区域生态风险评价方法。

“Triad”is a new kind of Weight-of-Evidence (WOE) approaches for ecological risk assessment, which is based on the three Lines of Evidence (LoEs): environmental chemistry, toxicology and ecology. Triad approach is being developed and applied in site-specific ecological risk assessment of contaminated lands in the western developed countries. In the present study, soils with different gradients of heavy metal concentrations will be collected from different land-use types within upstream-, middle stream- and downstream-areas of the Yanghe Watershed, a case study area, and ecosystems of different land uses will be investigated. Total concentrations of metals, their bioavailabilities as well as physicochemical properties of the collected soils will be analyzed. A battery of bioassays of different trophic level organisms exposed to the metal-contaminated soils will be conducted in lab. Ecosystem structures and functions in different land-use types within the watershed will be surveyed. Triad approach will be used for site-specific ecological risk assessment of the metal contaminated lands. Mechanisms influencing ecological risks will be obtained by statistically analyzing the relationships between soil properties, metal concentrations, bioavailabilities, and ecotoxicities as well as ecosystem structures and functions in different land-use types of the watershed. This study will provide scientific bases for remediation and management of metal contaminated soils and lands, and also will promote the development of landscape ecotoxicology and regional ecological risk assessment approaches in China.