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Posted: Mar 04, 2009

Regulating nanotechnology - how adequate is current regulation?

(Nanowerk Spotlight) A new PhD dissertation "Regulation and Risk Assessment of Nanomaterials – Too Little, Too Late?" by Steffen Foss Hansen from DTU Environment at the Technical University of Denmark finds that key pieces of the current European legislation are inadequate when it comes to regulating nanomaterials in the short and the long term. Hansen furthermore finds that the chemical risk assessment framework is inadequate to timely inform policy-makers about the health and environmental risks of nanomaterials, if not in the short term, then most definitely, in the long term.
The aim of the PhD dissertation which was successfully defended last Friday (Feb. 27), was threefold:

1) Investigate whether existing regulation is adequate in the short and the long term,

2) Explore the feasibility of risk assessment for the purpose of dealing with the complex emerging risks of nanomaterials and finally;

3) Provide recommendations on how to govern nanotechnologies.

As the public discussion about the regulation of nanotechnology in general, and nanomaterials in particular, heats up, emerging opinions on the applicability of existing regulation differ substantially and so do views on which regulatory options best address the current lack of information about environment, health and safety risks of nanomaterials, as well as the regulatory uncertainty and concerns expressed by the politicians, members of the public and industry, and investors.
Some argue that a completely new regulatory framework is needed, whereas others go even further and argue in favor of implementing a total moratorium on nanotechnology research, development and commercialization. And then there are those who argue for a laissez-faire attitude.
Understanding the limitations of the current regulation in regard to nanomaterials is a starting point in the process towards adapting existing laws and facilitating discussion about which kind of regulatory options is best to address these.
Hansen's dissertation presents an in-depth analysis of the key pieces of the current European legislation such as the chemical and pharmaceutical regulation, as well as the worker safety directives, and waste directives. He finds that – although nanomaterials might be covered by the general scope of many of the existing legislative frameworks – it is often unclear if current regulation is actually applicable when it comes to specific nanomaterials and their diverse applications.
According to Hansen, the main concerns with regard to the European chemical legislation, REACH (Registration, Evaluation and Authorization of Chemicals) are that it is unclear when a nano-equivalent of a bulk substance should be registered under REACH, and that production thresholds for when (eco)toxicological information has to be submitted, are not currently met for many nanomaterials (although they might be in the near future).
Furthermore, even though companies are urged to use already existing guidelines, both the European Commission and its Scientific Committee on Emerging and Newly-Identified Health Risks as well as others have pointed out that current test guidelines supporting REACH are based on conventional methodologies for assessing chemical risks and may not be appropriate for the assessment of risks associated with nanomaterials.
"Somewhat similar issues have been raised for pharmaceuticals where the concern is that current product standards may not be suitably designed to address various aspects relating to novel applications of nanotechnology in nanomedicine," says Hansen. "Furthermore, if the estimated environmental concentration of medical products is below 0.01 ppb and 'no other environmental concerns are apparent', no further actions are to be taken for the medical product in terms of environmental risk assessment. Such pre-defined action limit could potentially be problematic since the new properties of nanotechnology-based products are expected to also affect their environmental profiles."
Hansen groups the identified regulatory gaps into two categories:
The first category deals with whether nanomaterials are covered by current legislation when it comes to 1) definitions of a substance, novel foods, hazardous waste, etc. and 2) thresholds values not tailored to the nanoscale, but based on bulk material, see e.g. REACH.
The second category relates to the lack of metrological tools and toxicological data and the fact that occupational and environmental exposure limits cannot be established with existing methodologies – as required by some pieces of legislation e.g. pharmaceuticals regulation and the safety at workplace directives.
"So far" says Hansen, "the only amendment that has been implemented is to annul the exemption status of carbon and graphite under REACH, which is deemed inadequate to address the potential risks of nanomaterials and the current regulatory uncertainty. Low use concentrations by mass in the final product as well as low production/import volumes per producers would mean that many products that entail carbon nanomaterials would still not meet the requirement to be registered under REACH."
He continues to point out another problem, which is that many pieces of European legislation require or are based on the completion of a scientific risk assessment. Ever since discussions about nanotechnology-related risks have begun, chemical risk assessment has been put forward as the number one approach (along with life-cycle assessment to some extent) in regard to understanding the risks associated with the application of one kind of nanomaterials, namely nanoparticles, in our society.
In his dissertation, Hansen evaluates the applicability of each of the four individual steps of risk assessment (i.e. hazard identification; dose-response assessment; exposure assessment; and risk characterization) in the light of the current state of knowledge and he finds that each element of risk assessment holds general as well as specific limitations and challenges.
Hansen points out that, although various levels of toxicity have been reported for numerous nanoparticles, these need further confirmation before one can say that a hazard has been identified.
Hazard identification
"Multiple studies relevant for hazard identification have been carried out on fullerenes, carbon nanotubes, quantum dots and nanoparticles, however, many of these studies are not meant to facilitate risk assessment in the sense that they use non-standardized tests, have no coherent endpoint, and differ substantially with regard to species tested, methods of administration, dose range, way of particle preparation, duration of exposure, and effects observed and reported," says Hansen. "This definitely complicates hazard identification for most nanoparticles. Preliminary results furthermore indicate that the diversity of nanomaterials and their properties makes it an overwhelming challenge to conduct in vitro and in vivo evaluation of their biological effects. It is evident that the information provided is all over the map, making it impossible to systematically analyze the studies for properties of the nanoparticles which are important for the observed effects."
Dose-response assessment
The second element of risk assessment i.e. dose-response assessment assumes a 'no effect' threshold can be established and although some studies have reported observing a dose-response relationship there is no evidence of a dose threshold below which nanoparticle instillation ceases to cause, for instance, inflammation.
Hansen explains that a dose-response assessment is furthermore hindered by the fact that it is unclear what the best descriptors for dose is and which properties determine or influence the inherent hazards of nanoparticles. "The current lack of characterization of the nanoparticles tested in various studies makes it impossible to identify causality between observed hazards and specific physical and chemical properties" he says. "There is furthermore substantial limitation in our ability to determine individual and multiple particle characteristics simultaneously and in a consistent manner – both prior and during tests – when using different characterization techniques and/or across laboratories."
Exposure assessment
Exposure assessment i.e. the third element of risk assessment, was found to be handicapped by difficulties in monitoring nanomaterial exposure in the workplace and the environment, and by the fact that the biological and environmental pathways of nanomaterials are still largely unexplored.
The assessment of worker exposure is made difficult by issues such as the lack of one consistent sampling method that can be used to characterize exposure in real-time and by lack of information and data, for example, about how many workers are potentially exposed, what kinds of nanomaterials workers are or might be exposed to, where and how they are exposed and at which concentrations, by dose or by particles number, and what kinds of protective measures there are used or available.
As with worker exposure, analytical methods to detect and quantify concentrations of nanoparticles in the environment have yet to become available. The total load to the environment from current of nanomaterials is unclear. Several studies have tried to assess current and future consumer and environmental exposure for individual products, nanomaterials, and applications as well as product types. Many of these have been able to apply fairly simple mathematical equations and/or information available in the European guidelines for chemical risk assessment to estimate the current and future exposure for nanomaterials.
However, in order to assess the consumer and environmental exposure to nanoparticles, numerous assumptions had to be made, for instance: worldwide production volumes of nanoparticles; number of products produced entailing nanoparticles and at what concentrations; current and future market penetration; release from products throughout the life-cycle of the products by mass or other relevant metric(s); to what extend products become incinerated, end up in landfills or the sewage treatment plants, or end up directly in the environment; and release from waste incinerators and removal efficacy in the sewage treatment plants, and their fate and distribution in surface water, soil and the air.
Hansen says that these studies, no doubt, hold great value in regard to assessing the applicability of exposure assessment and should be seen as 'proof of principle' rather than actual assessment of the exposure. "Paucity of knowledge and lack of access to information hampers realistic exposure assessments."
What is worrying is that the present analysis of risk assessment identified a number of limitations and flaws in relation to each of the four elements of the risk assessment framework when applied to nanomaterials. It is currently impossible to systematically link reported nanoparticle properties to the observed effects for effective hazard identification. For dose-response assessment, it was unclear whether a 'no-effect' threshold can be established and what the best hazard descriptors of nanoparticles are, and what the most relevant endpoints are.
Hansen notes that there is a serious lack of characterization of the nanoparticles tested, which makes it difficult to identify which key characteristics – or combinations of key characteristics – determine the hazards documented in (eco)toxicological studies of nanoparticles. Risk characterization being at the end of the line, the sum or maybe even the power of all of these limitations are conveyed to estimating the risks for nanomaterials.
Considerable work is still required if future risk assessment of nanomaterials and products is to be relevant and reliable. Given that coordinated action to respond to the limitations of risk assessment and uncertainty seems to be slow in emerging, Hansen raises questions about whether risk assessment is indeed the most feasible approach to address the risk of nanomaterials.
In 2001, a report ("Late Lessons from Early Warnings: The Precautionary Principle 1896 - 2000"; pdf download, 1.8 MB) written by an expert panel commissioned by the European Environment Agency (EEA) on how to avoid repeating the mistakes of the technological development recommended looking out for 'warning signs' such as materials exhibiting novelty, persistency, readily dispersed, bio accumulative, and that lead to irreversible action.
These characteristics apply to many nanomaterials, some of which have novel properties, are capable of being incorporated in highly diverse products, may be transported to places in new ways, and may be designed to be persistent.
Hansen concludes that too little is known to predict the environmental fate of nanomaterials and feasible documentation of environmental dispersion through monitoring is not expected in the short term. "The extent to which specific nanomaterials are bio accumulative or lead to irreversible action is largely unknown, but the current state of knowledge suggests that the potential exists for such behavior under some circumstances. The global response to these warning signs has been patchy, at best. In general, government policy has been slow to respond, to gather essential data on production and to use patterns and personal protection equipment. Arguably, efforts have been better than those seen with many earlier technologies but they are still far from ideal."
By , Copyright Nanowerk LLC

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