Toxicity of soil-dwelling organisms to nZVI

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Nano zero-valent iron (nZVI) has great potential for remediation of soil contaminants, particularly organiccompounds that are recalcitrant to microbial degradation or weathering. However, risk assessments of nZVItoxicity to soil dwelling organisms native to Canada have yet to be conducted; this knowledge is required toensure that the remediation doesn't cause harm. Soil organisms such as earthworms, plants, and invertebratesmay be exposed to nZVI as a result of remediation activities, and due to its small size, anaerobic bacteria in thesoil may also be impacted significantly. Determining the toxicity thresholds for nZVI to soil dwellingorganisms using protocols developed by Environment and Climate Change Canada (ECCC) would allowCanada to adopt the lead position in this field and allow for informed decisions to be made concerningregulations relevant to contaminated sites. Such sites are vast in number including active and legacy sites thatare being managed by the company, as well as abandoned and orphaned sites. This is the first objective of theproposed work. The second objective of the proposed work is to express these toxicity thresholds as measuredconcentration of nZVI in soil rather than nominal, requiring the adaptation and validation of existing detectionmethods for aqueous systems.