School of Environmental Sciences, University of Hull, Kingston upon Hull, UK.
School of Earth and Environment, University of Leeds, Leeds, UK.
Environ Sci Pollut Res Int. 2024 Jun;31(29):42428-42444. doi: 10.1007/s11356-024-33897-4. Epub 2024 Jun 14.
Iron and steel slags have a long history of both disposal and beneficial use in the coastal zone. Despite the large volumes of slag deposited, comprehensive assessments of potential risks associated with metal(loid) leaching from iron and steel by-products are rare for coastal systems. This study provides a national-scale overview of the 14 known slag deposits in the coastal environment of Great Britain (those within 100 m of the mean high-water mark), comprising geochemical characterisation and leaching test data (using both low and high ionic strength waters) to assess potential leaching risks. The seaward facing length of slag deposits totalled at least 76 km, and are predominantly composed of blast furnace (iron-making) slags from the early to mid-20th Century. Some of these form tidal barriers and formal coastal defence structures, but larger deposits are associated with historical coastal disposal in many former areas of iron and steel production, notably the Cumbrian coast of England. Slag deposits are dominated by melilite phases (e.g. gehlenite), with evidence of secondary mineral formation (e.g. gypsum, calcite) indicative of weathering. Leaching tests typically show lower element (e.g. Ba, V, Cr, Fe) release under seawater leaching scenarios compared to deionised water, largely ascribable to the pH buffering provided by the former. Only Mn and Mo showed elevated leaching concentrations in seawater treatments, though at modest levels (<3 mg/L and 0.01 mg/L, respectively). No significant leaching of potentially ecotoxic elements such as Cr and V (mean leachate concentrations <0.006 mg/L for both) were apparent in seawater, which micro-X-Ray Absorption Near Edge Structure (μXANES) analysis show are both present in slags in low valence (and low toxicity) forms. Although there may be physical hazards posed by extensive erosion of deposits in high-energy coastlines, the data suggest seawater leaching of coastal iron and steel slags in the UK is likely to pose minimal environmental risk.
钢铁渣在沿海地区的处置和有益利用方面有着悠久的历史。尽管已经沉积了大量的渣，但对于沿海系统来说，综合评估钢铁副产品中金属（类）浸出的潜在风险仍然很少。本研究提供了英国沿海环境中 14 个已知渣场的全国性概述（位于平均高潮位 100 米以内的渣场），包括地球化学特征和浸出试验数据（使用低离子强度和高离子强度水），以评估潜在的浸出风险。渣场的向海延伸长度至少为 76 公里，主要由 20 世纪早期到中期的高炉（炼铁）渣组成。其中一些形成了潮汐屏障和正式的海岸防御结构，但更大的渣场与许多前钢铁生产地区的历史沿海处置有关，特别是英格兰坎布里亚海岸。渣场主要由钙镁橄榄石相（如硅灰石）组成，有次生矿物形成的证据（如石膏、方解石），表明有风化作用。浸出试验通常显示，在海水浸出情况下，元素（如钡、钒、铬、铁）的释放量低于去离子水，这主要归因于前者提供的 pH 缓冲作用。只有锰和钼在海水处理中显示出较高的浸出浓度，尽管浓度适中（分别为<3 毫克/升和 0.01 毫克/升）。在海水中，没有明显浸出潜在生态毒性的元素，如铬和钒（两者的浸出液浓度均<0.006 毫克/升），微 X 射线吸收近边结构（μXANES）分析表明，这些元素在渣中均以低价（和低毒性）形式存在。尽管在高能海岸线大量侵蚀渣场可能会带来物理危害，但数据表明，英国沿海钢铁渣的海水浸出可能不会造成最小的环境风险。
