[WATER] Development of a quantitative risk assessment model for diffuse pollution from estuarine landfill sites associated with climate change

根据目前对气候变化的预测，河流和河口的水文很可能随着海平面上升、沿海洪水和降水量增加而发生变化，导致许多河流系统的上游河口出现盐碱入侵和河岸侵蚀（IPCC 2007）。这对位于河流和河口岸边或附近的许多垃圾填埋场构成了重大威胁，因为这些地方污染物扩散排放的可能性尚未量化，而且人们对此知之甚少。垃圾填埋场管理人员有责任注意邻近的水生环境。然而，目前很少有工具来评估与气候变化引起的水文状况变化相关的河流和河口风险。博士项目的主要目标是：开发一个定量风险评估模型（RAM）与气候变化相关的河口垃圾填埋场扩散污染。研究目的（RO）：1.评估目前释放的扩散污染和潜在的垃圾填埋场失败，在上河口垃圾填埋场2。了解盐水入侵后污染物行为的变化3.了解盐分侵入后堆填区物料的岩土性质变化及堆填区的稳定性。制定一个定量的记录和档案管理，以评估填埋场盐水侵入后扩散污染物向水生环境的释放。这将提高对岸边垃圾填埋场扩散污染的基本理解，并为RO 4下的模型开发提供基线数据和输入参数。1)实地调查（第一年）：为了解决RO 1，学生将在泰晤士河口的雷纳姆沼泽地进行历史性的Crossways垃圾填埋场的环境质量和岩土工程调查。取样、土壤/沉积物和孔隙水的环境分析以及填埋场破坏的岩土工程评估将根据环境评估准则，根据当前条件进行。将对数据集进行审查，以探讨环境和岩土参数之间的关系，并确定扩散污染物释放的途径。2)基于实验室的调查（第2年）：为了解决RO 2，将使用批量吸附实验确定污染物在当前和盐水条件下的吸附行为。为了解决RO 3对土壤结构的影响，将在盐水入侵前后使用整体测试观察岩土性能和矿物学，其中填埋材料将悬浮在海水溶液中。将在周围溶液中测量分析物浓度的时间变化，将使用扫描电子显微镜观察土壤结构和矿物学。3)风险评估模型（第3年）：土工模型评估结构破坏的风险（如目前匈牙利墙倒塌），但不能预测释放的沉积物中污染物的行为。在这里，环境RAM，加上岩土和流体力学模型，将允许更好地评估风险和确定控制潜在的污染物释放。培训：研究培训和PPD通过QMUL内的正式授课课程提供。学生还将接受特定主题的培训;样本收集，环境分析，现场/调查技术，垃圾填埋场的监管方法 *，岩土工程现场调查 * 和风险评估建模 *（* 在Arcadis）。学生将参加两个PG授课课程1）多元统计（UCL）和2）生物地球化学循环（QMUL）。产出：产出将包括：更好地了解气候变化后填埋场失效和扩散污染物释放的可能性，与气候变化相关的风险评估协议，以及定量RAM。

Under current predictions for climate change the hydrology of rivers and estuaries is likely to change with sea level rise, coastal flooding and increased precipitation, resulting in saline incursion and bank erosion in the upper estuaries of many river systems (IPCC 2007). This poses a significant threat to the many landfill sites situated on/near river and estuary banks, where the potential for diffuse discharge of pollutants has not been quantified and is poorly understood. Landfill managers have a duty of care towards the adjacent aquatic environment. Yet, currently there are few tools for assessing the risk to rivers and estuaries associated with changes to hydrological regime due to climate change. The main aim of the PhD project will be: To develop a quantitative risk assessment model (RAM) for diffuse pollution from estuarine landfill sites associated with climate change. Research objectives (ROs): 1. To assess the current release of diffuse pollution and potential for landfill failure in upper estuarine landfill sites 2. To understand the change in contaminant behaviour following saline intrusion 3. To understand the change in geotechnical properties of landfill materials and landfill stability following saline intrusion 4. To develop a quantitative RAM to assess the release of diffuse pollutants to the aquatic environment following saline intrusion of landfill sites Methodological approach: ROs 1-3 will be addressed by combining field- and laboratory- based investigations. This will improve fundamental understanding of diffuse pollution from bankside landfill sites and will also provide baseline data and input parameters for model development under RO 4. 1) Field-based investigations (Year 1): To address RO 1, the student will conduct environmental quality and geotechnical investigations of the historic Crossways landfill site on Rainham Marshes in the Thames Estuary. Sampling, environmental analysis of soil/sediment and pore water, and a geotechnical assessment of landfill failure will be carried out following EA guidelines, based on current conditions. Datasets will be examined to explore relationships between environmental and geotechnical parameters and to determine pathways of diffuse pollutant release. 2) Laboratory-based investigations (Year 2): To address RO 2, sorption behaviour of pollutants, under current and saline conditions, will be determined using batch sorption experiments. To address RO 3 changes to soil structure, geotechnical properties and mineralogy will be observed before and after saline intrusion using a monolith test, where landfill material will be suspended in a seawater solution. Temporal changes to analyte concentrations will be measured in the surrounding solution, soil structure and mineralogy will be observed using scanning electron microscopy. 3) Risk assessment modelling (Year 3): Geotechnical models assess the risk of failure of a structure (such as the current Hungary wall collapse), but cannot predict the behaviour of the contaminants in the released sediments. Here, an environmental RAM, coupled to a geotechnical and hydrodynamic model, will allow for a better assessment of risk and a determination of controls on potential contaminant release. Training: Research training and PPD are offered through formal taught courses within QMUL. The student will also receive subject specific training; sample collection, environmental analysis, field/survey techniques, regulatory approach to landfill*, geotechnical site investigations* and risk assessment modelling* (*at Arcadis). The student will attend two PG taught courses in 1) multivariate stats (UCL) and 2) Biogeochemical cycling (QMUL). Outputs: Outputs will include; an improved understanding of the potential for landfill failure and release of diffuse pollutants following climate change, protocols for risk assessment associated with climate change, and a quantitative RAM.