Remediation of mercury contaminated sediments

汞是一种剧毒元素，由于工业活动和其他活动，沉积物、土壤和水中的汞浓度经常升高。在还原性条件下，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积累。摄入高浓度的甲基汞可导致严重的神经系统疾病，应避免。在本研究中，将进行处理实验，以评估天然材料在稳定受污染河漫滩中汞的有效性，以尽量减少其向当地生态系统的释放。将进行实验室批量和柱状研究，以描述影响洪泛区沉积物、土壤和含水层固体中汞循环的物理和生物地球化学过程。将未受污染的河水与受污染的洪泛区物质进行反应，以评估汞向河水释放的程度。受污染的水将通过固相天然材料，如生物炭和改性生物炭，以评估代表性流动条件下的汞去除程度。将进行实验，以制定设计参数，以便在河流排放区沿岸全面安装工程反应处理垫，以防止汞向当地生态系统释放。天然试剂将与洪泛平原土壤共混，以促进汞的结合，从而可能抑制生物体的吸收。将对实验进行时间和空间监测，以确定处理系统对汞、甲基汞和相关地球化学参数的水中浓度的影响。在实验期间和实验结束时，将使用同步加速器x射线技术收集和分析固相样品，以评估汞的结合机制。预计这项研究将为管理汞污染场所提供替代办法，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.