Nanomaterials knowledge gaps highlighted
The possibility of a ‘Trojan Horse Effect’ of nanomaterials (NMs) needs more research, according to a study identifying knowledge gaps in the risk assessment of the substance.
The call for research into the safety implications of aggregation and agglomeration details that nanoscale entities may be loosely attached to bigger agglomerates and therefore may not be detected by the measurement devices in the size range below 100nm.
The aggregation of nanomaterials was just one area identified in apparent knowledge gaps despite ever-growing interest from industry.
The authors highlighted that all parties involved in NMs production should re-evaluate traditional methods and metrics in relation to nanoscale entities exposure and an ongoing review of all workplace particulate protection equipment.
They also called for better characterisation of NMs at production, and approaches that integrate rather than separate exposure and toxicity for realistic modelling.
Regulatory action
Hunt et al said regulatory bodies should encourage an industrial and innovation approach feeding mid and endof-life information into start-of life (design) plans to close the life cycle of NMs.
A report identified a lack of coherent, consistent and well-founded data, the need for realistic exposure scenarios, better established dose–response relationships, improved extrapolation from in vitro to in vivo, and the identification of relevant assessment parameters, detailed the study.
Hunt et al wrote that in particular, there is a need to:
- understand the dynamics of biological-nanomaterial interfaces. This includes, in the determination of NM fate and behaviour, the role and importance of the corona of biomolecules that tends to form around NMs in contact with environmental or biological fluids;
- to embark on long-term and repeated low dose studies; and
- to gather information about NM stability and reactivity and transformation throughout the NM lifecycle
General processes and areas of possible release of nanoscale entities and NMs are: the production process; the handling, packaging, use and misuse of such materials; the ageing processes of NMs; and end-of-life activities such as recycling and disposal.
What is a nanomaterial?
For regulatory and scientific purposes, the EC definition of “nanomaterial” will hopefully be the first step, in generating harmonisation initiatives needed in nanotechnology development.
The Commission’s definition states that: “Nanomaterial means a natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm – 100 nm.
“In specific cases and where warranted by concerns for the environment, health, safety or competitiveness the number size distribution threshold of 50% may be replaced by a threshold between 1 and 50%.
“By derogation from the above, fullerenes, graphene flakes and single wall carbon nanotubes with one or more external dimensions below 1nm should be considered as nanomaterials.”
The paper was based on the final scientific report for the EU project NanoImpactNet which concluded last year.
