Remediation of mercury contaminated sediments

汞是一种剧毒元素，由于工业和其他活动，沉积物、土壤和水中的汞浓度往往较高。在还原条件下，无机汞可以转化为毒性更大的甲基汞，并在食物链中生物积累。摄入高浓度的甲基汞会导致严重的神经疾病，应该避免。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的河流泛滥平原中汞的有效性，以最大限度地减少汞向当地生态系统的释放。将进行实验室批量和立柱研究，以确定影响泛滥平原沉积物、土壤和含水层固体中汞循环的物理和生物地球化学过程的特征。未受污染的河水将与受污染的泛滥平原物质发生反应，以评估向河水释放汞的程度。受污染的水将通过固相自然材料，如生物炭和改性生物炭，以评估在典型流动条件下的汞去除程度。为防止汞向当地生态系统释放，将进行试验，以制定工程反应处理垫在河流排泄区的全尺寸安装的设计参数。天然试剂将与滩涂土壤共混，以促进汞的结合，从而潜在地抑制生物的吸收。这些实验将在时间和空间上受到监测，以确定汞、甲基汞和相关的地球化学参数随处理系统的变化。在实验期间和结束时，将收集固相样品，并使用同步加速器x射线技术进行分析，以评估汞结合机制。这项研究预计将为加拿大提供管理汞污染场地的替代办法，以减少人类和其他生物暴露在剧毒汞和甲基汞化合物中。

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.