The benefits provided by the advancement of nano-technologies are expected to have more widespread effects than any other recent innovation. Frequently hailed as the next general-purpose technology, nanotechnologies promise to enable technological breakthroughs, which will impact the entire global economy in a way beyond that of the steam engine and electricity.
Like any other new technology, however, early applications and implementations of nanotechnologies are surrounded by uncertainties and worries about the potential effects on environmental and human health and safety. In particular, the manufacture and application of nanomaterials has been a recent cause for concern that has initiated a number of public debates.
One of the challenges for manufacturers and users of nanomaterials is that, until recently, there has been no published guidance on the handling and disposal of nanoparticles and other nanoscale entities. Recognizing this gap, BSI, the British Standards Institution, has recently published a Guide to safe handling and disposal of manufactured nanoma-terials (PD 6699-2).1 Reflecting current concerns about potential risks posed by new nanoscale materials, including nanoscale forms of certain existing materials, the guide proposes that companies adopt a cautious approach to handling and disposal and recommends that, in the absence of sufficient information to the contrary, all such materials are considered potentially hazardous. The guide is one of a suite of nine documents that BSI published at the end of 2007, all of which are available free of charge.1 These documents—six sector-specific terminologies: medical health and personal care applications of nanotechnology (PAS 131); the bio-nano interface (PAS 132); nanoscale measurement and instrumentation(PAS 133); carbon nanostructures (PAS 134); nanofabrication (PAS 135), and nanomaterials (PAS 136); good practice guide to specifying nanomaterials (PD 6699-1); the guide to safe handling and disposal of manufactured nanomaterials; and guidance on labeling of manufactured nanoparticles and products containing manufactured nanoparticles (PAS 130)—will help to support worker, public, and environmental safety, underpin commercialization and procurement, provide consumers with information about the nanoparticle content of products, and contribute to the consistent usage of terminology in this emerging field.
At the same time, multinational organizations have started to look at nanotechnologies’ R&D and commercialization in the context of global corporate governance models. The most comprehensive guidance in this area, the Responsible Nano Code,2 requires board accountability for high levels of stakeholder involvement, worker health and safety, environmental and public health and safety, social, environmental, health, and ethical impacts, business partner engagement, and transparency and disclosure. The Code was developed by a working group of investment banks, NGOs, unions, large international and small national companies, toxicologists, consumers organizations, and social scientists.
CASE STUDY OF NANOMATERIAL RISK ASSESSMENT
One of the nanotechnology-focused companies on the working group of the Responsible Nano Code is Oxonica, a UK-based company that operates in the area of nanomaterials and has a portfolio of new products for applications for diverse sectors including fuels, cosmetics, medical diagnostics, and security. In support of the successful commercialization of a number of nano-material-based products, they have developed thorough risk assessment schemes in order to address the concerns about the impact of nanomaterials on human and environmental health and safety, which could arise from the unique nature of materials and processes at the nanometer scale. Owing to its policy of no animal testing, the company reviewed the risk assessment options for nanomaterial-based applications and, with the assistance of a number of experts in the fields of toxicology and air quality analysis, defined in vitro tests considered to confirm the safetyof its products.
One of their commercially available products, EnviroxTM, is a diesel fuel combustion catalyst based on nanoparticulate cerium oxide. It has been demonstrated to reduce fuel consumption, green house gas emissions (CO2), and particulate emissions when added to diesel at levels of 5 mg/L.
Many previous studies have confirmed the adverse effects of a range of particulates and especially diesel exhaust particulates on respiratory and cardiac health. While its use contributes to a reduction in the particulate content in the air, it was necessary to demonstrate that its addition does not alter the intrinsic toxicity of particles emitted in the exhaust.
Studies were conducted at laboratories in the UK and France to evaluate safety in use of Envirox by addressing the classical risk paradigm. Hazard assessment was addressed by examining a range of in vitro cell and cell-free endpoints to assess the toxicity of cerium oxide nanoparticles as well as particulates emitted from engines using it. Exposure assessment has taken data from modeling studies and from airborne monitoring sites in London and Newcastle adjacent to routes where vehicles using this catalyst passed.
The series of in vitro assays used in the initial screening strategy were all based on validated, internationally accepted protocols and provided data on the potential toxicity of a nanoparticulate cerium oxide and non-nano cerium oxide as a result of effects on various toxicological endpoints such as local site of contact (dermal) irritation, general cytotoxicity, and mutagenicity. Also included was an evaluation of likely environmental effects. These tests demonstrated no differences in biological effects between nano and non-nano cerium oxide and therefore the data support the conclusion of a lack of any additional (eco)-toxicological potential effects for nano-cerium oxide compared with non-nano cerium oxide.
Exposure data have demonstrated that the levels of cerium oxide measured at the sites in London and Newcastle generated no significant effects in the in vitro tests conducted. From modeling studies assuming widespread use of Envirox in all diesel vehicles and assuming human exposure on a daily basis, the estimated internal dose for a referential human in a chronic exposure situation is much lower than the NOEL in the in vitro toxicity studies.
Exposure to nano cerium oxide as a result of the addition of this cat- alyst to diesel fuel at the current levels of exposure in ambient air is therefore unlikely to lead to pulmonary oxidative stress and inflammation which are the precursors for respiratory and cardiac health problems in humans.
APPLYING THE PARADIGM
While nanomaterial-based products are entering the market for many different applications, the work conducted by Oxonica has demonstrated that by applying the standard risk paradigm considering both hazard and exposure data, conclusions can be drawn about the potential risk in use of such products. The level of risk can then be balanced against the potential benefits of the product. This company continues to use this approach with its other products and has generated a similar set of data on an UV-absorber product.
Oxonica has a policy of sharing the data and conclusions from the studies conducted in peer reviewed journals as well as at international conferences and symposia to ensure awareness of the characteristics and benefits from use of its own products and also to encourage other companies producing nanomaterials-based products to adopt a similar approach.
Barry Park B.Sc., Ph.D., CChem, FRSC, FIMMM is the Chief Operating Officer for Oxonica. Barry is a co-author of more than 20 published papers and is an inventor on over 30 patent applications leading to over 120 patents granted worldwide.
Dr. Steffi Friedrichs is the Director of the UK Nanotechnology Industries Association (NIA), an industry-led trade organization that creates a clear single voice to represent the diverse industries’ views in the multi-stakeholder debate on nanotechnology.