Remediation of mercury contaminated sediments

汞是一种剧毒元素，由于工业活动和其他活动的影响，沉积物、土壤和水中的汞浓度常常升高。在还原条件下，无机汞可转化为毒性更大的甲基汞，并在食物链中进行生物累积。摄入高浓度的甲基汞可导致严重的神经系统疾病，应避免摄入。在这项研究中，将进行处理实验，以评估天然材料在稳定受污染河流漫滩中的汞以尽量减少其向当地生态系统释放的有效性。将进行实验室批次和柱研究，以表征影响洪泛区沉积物、土壤和含水层固体中汞循环的物理和地球化学过程。未受污染的河水将与受污染的洪泛区材料发生反应，以评估汞向河水中释放的程度。受污染的水将通过固相天然材料，如生物炭和改性生物炭，以评估在代表性流动条件下的汞去除程度。将开展实验，为沿着排放区的工程反应处理垫的全面安装制定设计参数，以防止汞释放到当地生态系统。天然试剂将与洪泛区土壤混合，以促进汞的结合，从而可能抑制生物体的吸收。将在时间和空间上对这些实验进行监测，以确定汞、甲基汞和相关地球化学参数在水溶液中的浓度随处理系统的变化。在实验期间和实验结束时，将收集固相样品，并使用同步加速器X射线技术进行分析，以评估汞的结合机制。该研究将为管理汞污染场地提供替代方法，以减少人类和其他生物体接触剧毒汞和甲基汞化合物，从而使加拿大受益。

Mercury is a highly toxic element often present at elevated concentrations in sediment, soils and water as a result of industrial and other activities. Under reducing conditions, inorganic mercury can be converted to more toxic methylmercury which bioaccumulates in the food chain. Ingestion of elevated concentrations of methylmercury can lead to severe neurological disorders and should be avoided. In this study, treatment experiments will be conducted to evaluate the effectiveness of natural materials for stabilizing mercury in a contaminated river floodplain to minimize its release to local ecosystems. Laboratory batch and column studies will be conducted to characterize physical and biogeochemical processes influencing mercury cycling in the floodplain sediment, soils and aquifer solids. Uncontaminated river water will be reacted with the contaminated floodplain materials to evaluate the extent of mercury release to the river water. The contaminated water will be passed through solid-phase natural materials, such as biochar and modified biochar, to evaluate the extent of mercury removal under representative flow conditions. Experiments will be conducted to develop design parameters for full-scale installations of engineered reactive treatment mats along river discharge zones to prevent release of mercury to local ecosystems. Natural reagents will be co-blended with floodplain soils to promote mercury binding and thus potentially inhibit uptake by organisms. The experiments will be monitored temporally and spatially to determine changes in aqueous concentrations of mercury, methylmercury and associated geochemical parameters in response to the treatment system. During and at the termination of the experiments, solid-phase samples will be collected and analysed using synchrotron x-ray techniques to evaluate mercury binding mechanisms. The study is expected to benefit Canada by providing alternative approaches for managing mercury-contaminated sites to decrease exposure of humans and other organisms to highly toxic mercury and methylmercury compounds.