Toxicity of NZVI to Soil-Dwelling Organisms: Measuring Dose in Soils

将纳米工程材料添加到棕地土壤中进行修复需要考虑这些材料相对于正在修复的污染物的风险所带来的环境风险。纳米零价铁颗粒（nZVI）作为一种土壤修复方法，用于降解或固定有机和无机土壤污染物、卤化有机化合物、多环芳烃、农药和重金属，已有十多年的历史。它在安大略省广泛使用的限制是，人们对使用nZVI对土壤生态系统的环境影响知之甚少。由于纳米颗粒的独特性质以及nZVI在土壤中的应用作为一种修复手段，必须进行环境风险评估。然而，任何形成或转化的物质都有可能在环境中持续存在，导致生物积累，并对生活在土壤中的微生物和生物体产生毒性。到目前为止，土壤中nZVI的特征还很差，其障碍是高质量的毒性研究必须报告测量浓度而不是名义暴露浓度，并且在复杂介质中量化nZVI的方法还没有很好地建立起来。有许多显微镜和光谱方法可以检测nZVI，但更大的挑战是量化（Shi et al., 2015）。一旦建立了量化能力，就可以确定各种表面活性剂对市售形式的nZVI的生态毒性影响。在本研究中应用的测量nZVI的方法是核磁共振（NMR）和化学氧化还原探针靛蓝二磺酸盐（I2S）。这些将用于测量土壤孔隙水中的NZVI，通过离心从实验介质中提取。对加拿大的好处是，尚未对加拿大特有的nZVI对土壤栖息生物的毒性进行战略风险评估。蚯蚓、植物、无脊椎动物等土壤生物可能接触到nZVI，由于其体积小，土壤中的厌氧菌也可能受到显著影响。这种调查将使加拿大在这一领域处于领先地位，并允许就条例作出知情的决定

Adding nanoengineered materials to brownfield soils for remediation would need to consider theenvironmental risks posed by these materials relative to the risks of the contaminant that is being remediated.Nano Zero-Valent Iron Particles (nZVI) have been used as a soil remediation method for more than a decade todegrade or immobilize organic and inorganic soil contaminants, halogenated organic compounds, PAHs,pesticides and heavy metals. The limitation to its broader use in Ontario, is that there is little knowledge of theenvironmental impact of the use of nZVI on soil ecosystems. Due to the unique properties associated withnanoparticles and the application of nZVI to soil as a means of remediation, environmental risk assessmentsmust be performed. However, there is potential for persistence in the environment of any formed ortransformed material, bioaccumulation, and toxicity to microbes and organisms living in the soil could result.So far, this is poorly characterized for nZVI in soils, the barrier to which is that high quality toxicity studiesmust report measured rather than nominal exposure concentrations, and methods for quantifying nZVI incomplex media are not well established. There are a number of microscopic and spectroscopic methods thatcan detect nZVI, the bigger challenge is quantification (Shi et al., 2015). Once capacity for quantification areestablished, the effect on ecotoxicity of the various surfactants on commercially available forms of nZVI can beidentified. The methodologies for measuring nZVI, to be applied in this study are Nuclear Magnetic Resonance(NMR), and the chemical redox probe indigo disulphonate (I2S). These will be used to measure NZVI in soilpore water, extracted from the experimental media by centrifugation. The benefit to Canada is that strategicrisk assessments of nZVI toxicity to soil dwelling organisms specific to Canada have yet to be conducted. Soilorganisms such as earthworms, plants, and invertebrates may be exposed to nZVI, and due to its small size,anaerobic bacteria in the soil may also be impacted significantly. Such investigation would allow Canada toadopt the lead position in this field and allow for informed decisions to be made concerning regulations