河口沉积物质量与生态风险的流域人类活动驱动机制

This proposal will integrate the watershed and gradient approaches to explore driving mechanisms of environmental and ecological changes in watersheds by anthropogenic activities. The proposed project will employ watersheds fully located in Zhejiang and Fujian provinces to generate a spatial gradient of anthropogenic activities. Estuarine sediments will be selected as a receptor to indicate environmental and ecological changes driven by anthropogenic activities in the watersheds. The environmental quality of estuarine sediments will be characterized by multi-contaminant based sediment quality guidelines with a contaminant spectrum of N, P, metals, PCBs, and PAHs. By coupling with environmental, biological, and ecological risk assessment approaches, a priority list of contaminants will be screened for each studied watershed. An indicative subsystem of environmental responses will be constructed using the priority contaminants. Meanwhile, an end member subsystem of anthropogenic activities in the watershed will be generated by integrating social and economic parameters, such as population, GDP and constituents, and land use, via multivariate analyses. A multivariate linear model will be constructed using the environmental response subsystem as the dependent variable and the end members of anthropogenic activities in the watersheds as independent variables, which contributions will be calculated. Rainfalls in dry and wet seasons will act as weights integrated into the model to understand effects of rain events on the environmental and ecological responses to anthropogenic activities. Findings from this proposal will contribute to the sustainable development in watersheds with the new Urbanization policy through providing information to policymakers for industrial structure adjustment, economic promotion and contaminant reduction.

本申请项目拟以流域为单元结合梯度研究法研究流域环境与生态演变的人类活动驱动机制。以浙闽省内发育河流流域为对象构建流域人类活动空间梯度，以河口沉积物为受体，应用污染物谱（N、P、重金属、PCBs和PAHs）综合表征河口沉积物环境质量，耦合环境风险、生物风险和生态风险多重评估甄选流域优控污染物清单，构建河口沉积物环境响应子系统；以流域城镇人口、经济结构和土地利用组成等社会经济因素构成的人类活动梯度，解析人类活动端元，构建流域人类活动端元子系统；耦合人类活动端元和沉积物环境响应子系统，应用一次多元模型揭示流域尺度下河口沉积物环境质量演变（因变量）的人类活动端元（自变量）贡献规律；并以枯水季和丰水季流域降雨量为权重，分解人类活动端元的环境影响驱动模式，诠释降雨事件对环境响应的影响。本项目完成以期为落实“新型城镇化政策”的流域可持续发展、产业结构调整、经济提升和污染物消减提供政策建议和科学依据。

流域城镇化过程的生产和生活活动排放污染物可影响其河口沉积物环境质量及生态风险。本项目以梯度研究法研究了我国典型河口沉积物环境质量及其生态风险的流域城镇化驱动机制：1）以典型省内流域为对象，以县级社会经济和污染物排放（氨氮和COD）统计数据甄选出基于流域社会经济发展表征指标，即非农人口人均非农GDP（NAGDP per capita），并以此应用环境Kuznets曲线模型和多变量分析技术揭示了研究流域社会经济发展模式（即低环境影响、中等环境影响和高环境影响发展模式），结合流域城镇土地利用率形成研究研究流域的社会经济发展空间梯度，建立了流域尺度环境经济发展表征指标甄选和表征方法论；2）根据国家沉积物环境质量标准污染物谱综合评估研究流域河口沉积物在枯水期、丰水期及台风季的环境质量时空演变，耦合相应流域社会经济发展空间梯度甄别了河口沉积物重金属汇的流域陆源，即制造业和能源消费及其他人类生产活动源，建立了基于污染物谱的综合环境风险表征及优控污染物识别方法论；进一步拓展了人畜药物为人类活动指标，在其中的研究流域（九龙江）20个子流域揭示人畜药物水体残留的城镇化梯度效应，补充了人类生活活动源；3）沉积物氮循环连续过程和底栖贝类为生态功能对象，探索了流域经济发展驱动河口环境质量变化下的生态风险，明确了河口沉积物环境污染物谱对流域经济发展模式改变的响应敏感性，但沉积物氮循环过程和贝类的沉积物环境质量演变响应不显著，或由于研究河口沉积物环境质量相对较高（好于国家标准3类阈值）或存在一定的滞后效应；并且发现贝类外壳可能比其肌肉组织能更好地表征沉积物环境质量变化，为未来的沉积物生物风险标志物研究提供了新思路，但有待进一步验证。本项目完成培养了硕士和博士毕业生各1名以及助理研究员和副教授各1名，硕转博1名，1名博士生即将答辩；发表相关标注学术论文8篇（SCI 6篇），另有1篇SCI论文接收；相关成果促成两项国际合作项目资助。