Akvaplan-niva AS, Fram Centre, High North Research Centre for Climate and the Environment, Hjalmar Johansens gate 14, 9007 Tromsø, Norway; Department of Chemistry, UiT-The Arctic University of Norway, Norway.
Department of Chemistry, UiT-The Arctic University of Norway, Norway; Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, S-971 87 Luleå, Sweden.
Mar Pollut Bull. 2022 Nov;184:114197. doi: 10.1016/j.marpolbul.2022.114197. Epub 2022 Oct 5.
At present, there are no standardised tests to assess metal leaching during submarine tailings discharge. In this study the influence of variables known to affect metal mobility and availability (dissolved organic carbon (DOC), pH, salinity, temperature, aerated/anoxic conditions) along with variables affected by the discharge conditions (flocculant concentration, suspension) were studied in bench-scale experiments. The leaching tests were developed based on the case of a copper mine by Repparfjorden, northern Norway, which is planned to re-open in 2022. The experiments, which had three week duration, revealed low (<6 %) leaching of metals. Multivariate analysis showed that all variables, apart from DOC, highly influenced leaching and partitioning of at least one metal (Ba, Cr, Cu, and/or Mn). The high quantity of the planned annual discharge of mine tailings to the fjord (1-2 million tonnes) warranted estimation of the leached quantity of metals. Multivariate models, using present-day conditions in the fjord, estimated leaching of up to 124 kg Ba, 154 kg Cu and 2400 kg Mn per year during discharge of tailings. Future changes in the fjord conditions caused by climate change (decreased pH, increased temperature) was predicted by the multivariate models to increase the leaching up to 55 %, by the year 2065. The bench-scale experiments demonstrated the importance of including relevant variables (such as pH, salinity, and temperature) for metal leaching and -partitioning in leaching tests. The results showed that metal leaching during discharge is expected and will increase in the future due to the changed conditions caused by the foreseen climate change, and thereby underline the importance of monitoring metal concentrations in water during operations to determine the fate of metals in the fjord.
目前，还没有标准化的测试方法来评估海底尾矿排放过程中的金属浸出。在本研究中，研究了已知影响金属迁移性和可用性的变量（溶解有机碳（DOC）、pH 值、盐度、温度、充气/缺氧条件）以及受排放条件影响的变量（絮凝剂浓度、悬浮液）。浸出试验是基于挪威北部 Repparfjorden 的一个铜矿案例开发的，该铜矿计划于 2022 年重新开放。为期三周的试验表明，金属浸出率较低（<6%）。多元分析表明，除了 DOC 之外，所有变量都高度影响至少一种金属（钡、铬、铜和/或锰）的浸出和分配。由于计划将矿山尾矿每年以 100 万至 200 万吨的数量排入峡湾，因此有必要估算金属的浸出量。使用峡湾目前的条件，多元模型估计每年在尾矿排放过程中浸出多达 124 千克钡、154 千克铜和 2400 千克锰。多元模型预测，未来由于气候变化（pH 值降低、温度升高）引起的峡湾条件变化，到 2065 年，浸出量将增加 55%。小型试验表明，在浸出试验中，包括相关变量（如 pH 值、盐度和温度）对金属浸出和分配非常重要。结果表明，由于预期的气候变化引起的条件变化，排放过程中的金属浸出是预期的，并将在未来增加，因此强调了在运营过程中监测水中金属浓度以确定金属在峡湾中的命运的重要性。
