9. Conclusion – Are existing methodologies to assess the potential human health and environmental risks associated with products of nanotechnology appropriate?
To the question: “Are existing methodologies appropriate to assess potential and plausible risks associated with different kinds of nanotechnologies and processes associated with nanosized materials as well as the engineered and adventitious products of nanotechnologies?”, the SCENIHR is of the opinion that:
- Although the existing methods are appropriate to assess many of the hazards associated with the products and processes involving nanoparticles, they may not be sufficient to address all the hazards.
- More specifically, the mode of delivery of the nanoparticle to the test system should adequately reflect the exposure scenarios. Additional tests may be needed.
- Expressing the dose of exposure in terms of mass alone is not sufficient; it also needs to be expressed in terms of total surface area, number of particles, or a combination of the two.
- Also, the existing methods used for environmental exposure assessment are not necessarily appropriate.
- Therefore, the current risk assessment procedures require modification for nanoparticles.
To the question: “If existing methodologies are not appropriate to assess the hypothetical and potential risks associated with certain kinds of nanotechnologies and their engineered and adventitious products, how should existing methodologies be adapted and/or completed?””, the SCENIHR is of the opinion that:
Existing methodologies need to be modified or new ones developed so that they are able:
- to determine the physical and chemical properties of nanoparticles routinely.
- to measure the representative exposure to free nanoparticles in air, soil, water...
- to better assess the potential hazard of nanoparticles, including whether or not they can exacerbate pre-existing medical conditions.
- to better detect the movement of nanoparticles inside living systems.
More specifically, these methodologies need to provide information on how nanoparticles distribute in human tissues and in the environment.
To the question: “In general terms, what are the major gaps in knowledge necessary to underpin risk assessment in the areas of concern?””, the SCENIHR is of the opinion that:
The major gaps in knowledge that need to be filled to allow for satisfactory risk assessments for humans and ecosystems to be performed include:
- the mechanisms and the rate at which nanoparticles are released from products and processes.
- the actual levels of exposure to nanoparticles, both for humans and the environment.
- the extent to which it is possible to calculate the toxicology of nanoparticles from the knowledge on the same chemicals in larger physical forms.
- the movement of nanoparticles inside the body, the effects that nanoparticles cause at cellular level, and how target organs respond to different doses of nanoparticles.
- the exposure and related health effects of workers involved in the production and processing of nanoparticles.
- the behaviour of nanoparticles in the environment, how they are distributed, if they persist in it, and whether they accumulate in different species, including micro-organisms.
- the effects of nanoparticles on various environmental species.