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Regulation and risk assessment of nanomaterials – Too little, too late?

Regulation and risk assessment of nanomaterials – Too little, too late?
Steffen Foss Hansen

2009

Department of Environmental Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, DENMARK.

ABSTRACT

Nanotechnology is the latest in a long series of technologies heralded as ushering in a new era and current and future applications of nanotechnology are expected to hold immense societal and environmental benefits. Concerns have been raised about the safety and regulation of nanomaterials following a number of studies which indicated that some nanomaterials can cause adverse effects on laboratory animals. Data on nanoparticles, such as increasing production volumes and commercialization, capabilities to cross biological barriers, and increased biological activities of nanoparticles when compared to bulk counterparts, have worried some scientists, policy-makers, members of the public and industry and investors about their potential impacts on the health and safety of both humans and the environment.

The aim of this PhD Thesis is to: 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.

The short and long term development of nanotechnologies and nanomaterials was investigated and an in-depth analysis was performed of key pieces of regulation in the EU such as REACH, pharmaceutical regulation, and the worker safety directives, and waste directives. The applicability of each of the four individual steps of risk assessment (i.e. hazard identification, dose-response assessment, exposure assessment, and risk characterization) was evaluated in the light of the current state of knowledge.

It is found 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. The main problems seem to be: that requirements to do safety evaluations are triggered by production volumes by tonnage not tailored to the nanoscale, the profound lack of (eco)toxicological data, and that no risk thresholds and occupational exposure limits cannot be established with existing methodologies.

So far, 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.

Several governments have opted to implement voluntary environmental programs (VEPs), arguing that this is the only viable proportional option for the time being. It is generally known that key elements of any successful VEP are: incentives to participate for various stakeholders, agency guidance and technical assistance, signed commitments and periodical reporting, quality of information, and transparency both in design, reporting and evaluation. However, many of these elements have not been fully addressed in the VEPs that are implemented currently on nanomaterials.

Each of the four steps, that together constitute the risk assessment framework hold a number of limitations as well. Toxicity has been reported on for multiple nanoparticles, but for most nanoparticles these need further confirmation before one can say that a hazard has been identified. It is currently impossible to systematically link reported nanoparticle properties to the observed effects for effective hazard identification. Although some studies have reported observing a dose-response relationship, it was unclear whether a no effect threshold can be established and what the best hazard descriptor(s) of nanoparticles is and what the most relevant endpoints are. 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. Several studies have tried to assess current and future consumer and environmental exposure for nanomaterials, but these should be seen as “proof of principle” rather than actual assessment of the exposure. Realistic exposure assessment is hampered by: paucity of knowledge, lack of access to information, 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. Risk characterization being at the end of the line, the sum or maybe even the power all of these limitations are conveyed to calculating risk quotients for nanomaterials.

It is concluded that we do not know enough to say that nanomaterials are safe, but that there is evidence that some nanomaterials are hazardous depending on their particle characteristics, how they are applied and how humans and the environment are exposed to them. Although recognizing that adaptations are needed, risk assessment has repeatedly been proposed by expert committees, policy-makers, members of industry and non-governmental organizations as means to inform decision-makers about the risks of nanomaterials. However, in this thesis, risk assessment is found to be 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. Risk assessment is not feasible for the purpose of dealing with the complex emerging risks of nanomaterials and will not be adequate to ensure a decision-making process that enables us to make informed decisions within a reasonable period of time. It is furthermore concluded that the existing regulation is not adequate to deal with nanomaterials in the short and the long term and that too little is being done currently to amend existing regulation through the incremental approach adopted by the EU and the voluntary program implemented in the UK. It is recommended that current regulation is adapted immediately to reflect the challenges posed by current nanomaterials and their applications. Risk assessment should be abandoned as the primary decision making tool. Alternative tools such as MultiCriteria Decision Analysis, Bayesian decision making and Adaptive management should be pursued to ensure and support transparent and informed decision-making processes.