Ecological remediation of urban legacy pollution: Developing a neosoil for marginal brownfield bioremediation

运河作为在城市地区提供娱乐和生态效益的重要绿地日益受到重视(Williams等人，2010年)。然而，他们的工业历史留下了污染的土壤和沉积物，以及与之相关的糟糕的水质。因此，英国运河网络的大段需要对重金属进行大量修复，才能适合公众使用。主要的清理方法需要挖掘和异地补救(Bromhead等人，1994年)。对于边际公共土地来说，这往往过于昂贵，因此需要一种替代的、原地的、低成本的方法来使这些地区重新得到有益的使用。堆肥技术的最新进展为改善就地生物修复的环境可持续性提供了机会(周等人，2022)。氨基酸(Dolv等人，2020)和其他低分子有机酸(Wang等人，2019年)等天然螯合剂提供了很有希望的新方法，可以提高修复效率，而不会对土壤功能和结构产生EDTA等合成的、不可生物降解的螯合剂的负面影响(Jelusic和Lista，2014；Bloem等人，1917)。同样，根分泌物富含草酸、半乳糖和甘油酸的植物已被证明能有效去除受污染土壤中的铅(Luo等人，2017)。大多数关于重金属修复的研究都集中在单一或有限数量的污染物上。然而，这并不反映现场遗留的污染，即在一个单独的地点通常存在多种污染物。例如，伯明翰迪格贝斯的大联合运河有九种重金属浓度超过规定值(图1)。该项目的创新之处在于，通过生产一种可在英国类似污染地点使用的低成本“新油”，专注于多种污染物的去除。该项目的主要目标是将受污染的城市边缘土地重新投入公共用途。因此，该项目将：(1)确定土壤改良剂(例如天然/螯合/有机)的最佳组合，用于土壤中重金属污染物的生物和植物修复；(2)检查修复的潜在负面后果，包括通过改变土壤化学、淋溶和分配到地上生物量而增加流动性；(3)为低成本修复英国境内类似污染的场地创建新土壤模板。

Canals are increasingly valued as an important green space providing recreational and ecological benefit in urban areas (Williams et al.,2010). However, their industrial past has left a legacy of polluted soils and sediments with associated poor water quality. As a result, large sections of the UK's canal network require significant remediation of heavy metals before being suitable for public use. The principal method of clean-up requires excavation and ex-situ remediation (Bromhead et al.,1994). This is often too costly for marginal public land and therefore an alternative, in-situ, low-cost method is needed to bring these areas back into beneficial use. Recent advances in composting technology offer an opportunity to improve the environmental sustainability of in-situ bioremediation (Zhou et al.,2022). Natural chelating agents such as amino acids (Dolev et al.,2020) and other low-molecular-weight organic acids (Wang et al,.2019) provide promising new ways to improve remediation efficiency without the negative impacts on soil function and structure afforded by synthetic, non-biodegradable chelators such as EDTA (Jelusic and Lista 2014; Bloem et al.,1917). Similarly, plants with root exudates high in oxalic, galactonic and glyceric acid have been shown to effectively remove lead in contaminated soil (Luo et al,.2017). Most research into heavy metal remediation is focused on a single or limited number of contaminants. However, this does not reflect in-situ legacy contamination where multiple contaminants are usually present at an individual site. For example, the Grand Union canal in Digbeth, Birmingham has nine heavy metal concentrations in excess of regulatory values (Fig.1). The novelty of this project is to focus on multi-contaminant removal via production of a low-cost "neosoil" that can be utilised at similarly contaminated sites in the UK. The project's principal aim is to bring contaminated urban marginal land back into public use. Accordingly, the project will: (1) identify the best combination of soil amendments (e.g. natural/chelate/organic) for bio- and phytoremediation of heavy metal contaminants in soils; (2) examine potential negative consequences of remediation including increased mobility via changes in soil chemistry, leaching and partitioning into aboveground biomass; (3) create a neosoil template for low-cost remediation of similarly contaminated sites within the UK.