March 23, 2009
Q&A: EU Testing of Nanomaterials
The field of nanotechnology is still in its infancy, and now is the time to ensure that frameworks for nanosafety testing are grounded in modern and human-relevant science, in order to prevent the needless deaths of millions of animals.
Q: What are nanomaterials?
A: Nanomaterials are substances that have been designer engineered at scales of less than 100 nanometers to achieve size-dependent properties and functions (1 nm = 1 billionth of a meter). Some nanomaterials are new-to-the-world creations (e.g., carbon nanotubes, quantum dots and fullerenes), while others are just smaller versions of existing materials (e.g., nanoscale gold and silver).
Q: Are nanomaterials already being used in commercial products?
A: Yes. A few of the many examples include a dental adhesive from 3M, Behr NanoGuard mildew-resistant paint, Eddie Bauer NanoCare khakis, General Motors’ Hummer H2, Henkel’s Nanit-Activ toothpaste, Petrol Ofisi gasoline, Proctor & Gamble Olay sunscreens, and Wyeth’s Rapamune immunosuppressant.
Q: Why test nanomaterials?
A: It is not known whether nanoscale materials present an inherently greater hazard to human health and/or the environment than larger-sized materials.
Q: How are nanomaterials regulated in Europe?
A: Current EU legislation does not contain specific provisions regarding nanomaterials; however, nano-forms of substances still fall within the scope of existing regulatory frameworks (e.g., chemicals, pharmaceuticals and cosmetics), which require the assessment of potential health and/or ecological hazards. The difficulty, however, is that most existing toxicity testing methods are generally considered [PDF] to be inadequate for the evaluation of substances in nano-form. Thus, it is anticipated that the EU will need to prepare technical guidance to support the implementation of existing regulatory requirements in relation to nanomaterials.
Q: How will the potential hazards of nanomaterials be evaluated in the EU?
A: Many different approaches are under discussion worldwide. In the EU, the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) has proposed the following multi-stage risk assessment framework for nanomaterials:
- Stage 1: Characterisation of physico-chemical properties (size distribution, solubility and stability)
- Stage 2A: Human/environmental exposure assessment to identify scenarios where significant exposure is anticipated
- Stage 2B: Examine potential for absorption
- Stage 3: Test for hazardous properties using a tiered system of in vitro and animal tests
- Stage 4: Characterisation of dose-response relationships and conclusions on the risks for each relevant exposure scenario
Q: Are animal tests accurate predictors of human health hazards?
A: Not necessarily. Serious limitations of animal tests for substances in bulk-form have already been well established. In addition, the opinion [PDF] of the EU’s SCENIHR scientific committee is that “In view of the specific characteristics demonstrated for nanoparticles and nanoparticle formulations, the assays usually performed for determining toxicity of products may not be sufficient to detect all possible adverse effects of nanoparticles.”
Q: What are the alternatives?
A: Although no validated nano-specific test methods of any kind are available at this time, rapid, non-animal in vitro tests are widely regarded as a critical cornerstone in nanosafety testing. For example, the SCENIHR has reported [PDF] that: “In vitro testing has provided mechanistic data on particle toxicology in general and many in vitro assays demonstrate convincing differences between low and high toxicity particles; it is therefore considered appropriate that in vitro testing is used in situations involving nanoparticles. There is however, a clear need for validated in vitro assays for nanoparticle evaluation, including assays with meaningful endpoints for genotoxicity tests. In vitro tests should address key properties of the nanoparticles such as biopersistence, free radical generation, cellular toxicity, cell activation and other generic endpoints and provide target cell-specific endpoints.”
Q: What is HSI Europe doing to help animals used in nanomaterials testing?
A: HSI Europe has been at the forefront of lobbying efforts to ensure that all available, validated non-animal methods and testing strategies achieve expeditious regulatory acceptance in the EU. Additionally, HSI Europe and affiliate organisations The Humane Society of the United States and Humane Society Legislative Fund have assumed a leading role in supporting implementation of the vision of “twenty-first century toxicology” articulated by the U.S. National Research Council, which would see animal tests that are decades old, costly, slow and of dubious relevance to people replaced by ultra-modern, efficient and human-relevant non-animal methods. HSI Europe is calling for a “big biology” project to meet this challenge, akin to the Human Genome Project of the 1990s, and are forging an international, multi-stakeholder consortium make this landmark vision a reality as quickly as possible.