Department of Ecology, Environment and Plant Sciences (DEEP), Stockholm University, Svante Arrhenius väg 20A, 106 91, Stockholm, Sweden.
Department of Ecology, Environment and Plant Sciences (DEEP), Stockholm University, Svante Arrhenius väg 20A, 106 91, Stockholm, Sweden; Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius väg 16 C, 106 91, Stockholm, Sweden.
Chemosphere. 2024 Oct;365:143398. doi: 10.1016/j.chemosphere.2024.143398. Epub 2024 Sep 24.
Sediments contaminated with hazardous metals pose risks to humans and wildlife, yet viable management options are scarce. In a series of laboratory experiments, we characterized Polonite® - an activated calcium-silicate - as a novel sorbent for thin-layer capping of metal-contaminated sediments. We tested a fine-grained by-product from the Polonite production as a cheap and sustainable sorbent. First, Polonite was reacted with solutions of Cu, Pb, and Zn, and the surface chemistry of the Polonite was examined using, e.g., scanning electron microscopy to investigate metal sorption mechanisms. Batch experiments were conducted by adding Polonite to industrially contaminated harbor sediment to determine sorption kinetics and isotherms. Importantly, we measured if the Polonite could reduce metal bioavailability to sediment fauna by performing digestive fluid extraction (DFE). Finally, a cap placement technique was studied by applying a Polonite slurry in sedimentation columns. The results showed rapid metal sorption to Polonite via several mechanisms, including hydroxide and carbonate precipitation, and complexation with metal oxides on the Polonite surface. Isotherm data revealed that the sediment uptake capacity (K) for Cu, Pb, and Zn increased by a factor of 25, 21, and 14, respectively, after addition of 5% Polonite. The bioavailability of Cu, Pb, and Zn was reduced by 70%, 65%, and 54%, respectively, after a 25% Polonite addition. In conclusion, we propose that sediment treatment with low doses of the Polonite by-product can be a cheap, sustainable, and effective remediation method compared to other more intrusive methods such as dredging or conventional isolation capping.
受有害金属污染的沉积物对人类和野生动物构成风险，但可行的管理选择却很少。在一系列实验室实验中，我们将 Polonite®——一种活性钙硅酸钠——鉴定为一种用于污染沉积物薄层覆盖的新型吸附剂。我们测试了 Polonite 生产的一种细颗粒副产品，作为一种廉价且可持续的吸附剂。首先，Polonite 与 Cu、Pb 和 Zn 的溶液反应，并用扫描电子显微镜等方法检查 Polonite 的表面化学性质，以研究金属吸附机制。通过向工业污染的港口沉积物中添加 Polonite 进行批量实验，以确定吸附动力学和等温线。重要的是，我们通过进行消化液提取 (DFE) 来测量 Polonite 是否可以降低金属对沉积物动物区系的生物利用度。最后，通过在沉降柱中应用 Polonite 泥浆来研究覆盖技术。结果表明，Polonite 通过多种机制快速吸附金属，包括氢氧化物和碳酸盐沉淀，以及与 Polonite 表面金属氧化物的络合。等温线数据表明，添加 5% Polonite 后，Cu、Pb 和 Zn 的沉积物吸收容量 (K) 分别增加了 25、21 和 14 倍。添加 25% Polonite 后，Cu、Pb 和 Zn 的生物利用度分别降低了 70%、65%和 54%。总之，我们提出，与疏浚或传统隔离覆盖等更具侵入性的方法相比，用低剂量的 Polonite 副产品处理沉积物可能是一种廉价、可持续且有效的修复方法。
