This factsheet discusses only the potential risks from the deployment of Nanoparticles (NPs) as nanoremediation technique, i.e. the risks on human health and environment from the nanoparticles themselves. The risks from the contamination problem being treated, including as a result of failure of the nanoremediation process such as the delivery of nanoparticles to the contaminated media, or inadequate destruction of contaminants or of residual contamination are not discussed here:
Appropriate use of nanoremediation should have the same level of confidence and the same safety requirements as applied to any otherin situ redox based remediation technique, some of which can depend on the introduction of potentially hazardous treatment reagents into the subsurface (for example hydrogen peroxide or permanganate). However, the general public’s concerns about nanotechnologies, and a lack of effective validated field performance data, mean that liable parties and / or regulators may pay particular scrutiny to nanoremediation use. NanoRem has produced independent and objective large and field scale performance data to support more robust decision-making Available from the NanoRem ToolBox (http://www.nanorem.eu/toolbox/bulletin-shelf.aspx#TB1).
The potential risks to human beings or the wider environment from the deployment of NPs into the sub-surface arises if:
1. The nanoparticles, including reactive and spent NPs, and associated coatings, modifiers or catalysts are harmful to human health or the environment, AND
2. A receptor is exposed to a harmful dose.
The first condition depends on the toxicity of the NPs, their mobility / stability, persistence and capacity to bio-accumulate which are closely linked with the NP physical properties (particle size, specific surface area) and its composition (FAQ: What are nano particles and how does remediation work?); The second condition is very much related to the site specific conditions (presence of NP source, pathway, receptor described in the conceptual site model), the remediation design and implementation (FAQ: What are nanoparticles and how does remediation work?); (injection method and quantity of injected reactive agent) and the propensity for the NPs to migrate to potential receptors (fate and transport of the NPs) (FAQ: What are nanoparticles and how does remediation work?).
Deployment risks should be considered at each step of the remediation process including the handling of the NPs on site, the injection of the reactive media, to the operation of the process, any post remediation monitoring (if required) and ultimate fate of the NPs. Correctly applied nanoremediation would not give rise to risks substantively greater than any other in situ chemical oxidation / reduction remediation technology.
NanoRem has produced guidance on its Bulletin 2 on the “appropriate use” of nanoremediation which is available from the NanoRem Tool Box (http://www.nanorem.eu/toolbox/bulletin-shelf.aspx#TB1). In addition, a detailed guidance on screening deployment risks is also provided in the Tool Box (http://www.nanorem.eu/toolbox/nanoparticles_and_tools.aspx#TB1), along with a general treatment of the risks vs. benefits of nanoremediation use and its exploitation (http://www.nanorem.eu/toolbox/project-deliverables.aspx).