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sábado, 10 de março de 2012

10 years of nanotechnology risk research - a European status update

A group of experts from the chemical industry and various research laboratories in Germany have published a report on the current status of risk research on nanotechnology materials and applications. The report – 10 Years of Research: Risk Assessment, Human and Environmental Toxicology of Nanomaterials (pdf) – provides an overview of the current state of risk assessment and toxicological research into nanomaterials. It also lists and summarizes the national and European projects on toxicology on various nanomaterials.
In their report, the working group "Responsible Production and Use of Nanomaterials" from DECHEMA(Society for Chemical Engineering and Biotechnology) and VCI (German Association of the Chemical Industry) has drawn up a list of topics and priorities which need to be addressed; activities and projects which have already been carried out; are currently on-going; or are still at the planning stage. The main focus of our considerations is on Germany, with a wider outlook on papers and results at European level.
The report draws the following general conclusions from the projects carried out to date under realistic conditions:

  • A risk assessment – where necessary in individual cases – should be performed on the basis of suitably modified and adapted OECD methods which have been validated and are internationally recognized. This confirms the OECD observation that the internationally recognized OECD methods and testing guidelines are suitable in principle for the testing of nanomaterials.

  • The size label 'nano' does not also immediately mean "toxic", so it does not represent an intrinsic hazard characteristic.

  • The authors point out that, in terms of research into the safety of nanomaterials, academia and industry often address different aspects:
    Research groups - especially university groups - tend to steer their projects towards research into more fundamental aspects, such as the fundamental principles of the action mechanisms involved in the interaction between nanomaterials and biological systems, and they develop fundamental methods for detection and characterisation.
    Industrial "Product Stewardship" programs assess the safety of products along their lifecycles, i.e. in manufacturing, further processing and in the planned applications. Consequently, these efforts are focused primarily on the products brought to market by the relevant companies.
    Above and beyond these two aspects, joint consortia made up of representatives of industry and academia can systematically develop fundamental mechanisms on commercially relevant systems or systems which are close to real-life applications. In combination, these should yield coherent structure-activity relationships, which can play a supporting role in influencing future product developments in industry.
    In order to ensure that "nano" based products are safe, basic risk assessments are required for them, both in terms of their intended applications and in relation to their full lifecycle along value creation chains. According to the opinions of the relevant experts of the Organisation for Economic Cooperation and Development (OECD) and the Scientific Committee on Emerging and Newly Identified Health Risks, (SCENIHR) of the European Commission, these risk assessments can, in principle, be carried out with suitably adapted, validated and internationally recognized (e.g. OECD) methods (see for instance theOECD Database on Research into Safety of Manufactured Nanomaterials). From these, it will then be possible to derive appropriate measures (e.g. safe limits for the workplace) which will enable safe production, further processing, usage and recycling/reuse in the relevant value creation chain.
    The following varied factors and considerations must all form part of such a risk assessment: on the one hand, it needs to be investigated whether and, if applicable, to what level any release, i.e. emission of nanomaterials and/or nano-objects, is at all possible in an intended application. Furthermore, clarification needs to be sought whether the nanomaterials and/or nano-objects which may potentially be released can interact with surrounding biological systems, i.e. whether any exposure actually occurs in the relevant application.
    On the other hand, the interactions of the nanomaterial under assessment and its effects on biological systems, i.e. humans and the environment, need to be examined and classified under defined conditions, e.g. via a range of different exposure routes (oral, dermal, by inhalation etc.) and at different doses, i.e. exposure levels. As a result, not only are the possible exposure scenarios in the application of the nanomaterial and/or nano-object and its biological effects examined in isolation, but in order to properly conduct a risk assessment of a material in an application, both factors also need to be combined with each other in order to allow a general risk assessment to be concluded. This means that, for example, the absence of a relevant exposure in an application and/or the absence of a negative biological interaction during an expected corresponding exposure would indicate the absence of any risk in a given application.
    For relevant studies carried out for safety assessments, this therefore means that the biological effect (factor 1) needs to be systematically investigated under defined test conditions (defined test set-ups and comparison systems, characterized materials, defined exposure paths and exposure doses). In addition, realistic scenarios need to be drawn up for the relevant application and corresponding exposure doses (factor 2) and exposure paths.
    By combining the mutually coordinated investigations into both factors, it will then be possible to perform a reliable risk assessment, from which it will also be possible to derive appropriate measures to minimise the risks associated with this application throughout the lifecycle.
    A range of such studies designed to deliver safety-related data for nanomaterials has already been conducted or is currently in progress. Examples include a number of projects, such as the BMBF-funded (BMBF = German Federal Ministry of Education and Research) NanoCare project, in which nanomaterials which are relevant in terms of practical applications were examined under realistic and reproducible test conditions, from which concrete systematic data were then obtained.
    In this context, the Nanoderm project funded by the European Commission is no doubt one of the most frequently cited projects, and it was able to show that nano-TiO2 does not penetrate through undamaged skin. In addition, the projects CarboSafe (since 2008) and CarboLifeCycle (since 2010) have also been set up and started as part of the Innovation Alliance Carbon Nanotubes (Inno.CNT). Here, environmental aspects as well as emission and exposure scenarios are investigated among other things for carbon nanotubes (CNTs).
    The NanoCare and NanoNature projects tendered by BMBF, which look at issues relating to human toxicity and interactions between nanoparticles and the environment, have also recently started. In addition, there are numerous projects and activities at European level within the framework of the 6th (already completed) and 7th EU research framework program which have now started up or recently put out to tender again.
    The results of the industrial safety research will particularly also serve as the basis for registrations under the REACH system at the European Chemicals Agency ECHA.
    Even if the current data available on environmental and human toxicity of numerous nanomaterials is already starting to reach satisfactory levels, this data is set to grow in further efforts carried out jointly between research scientists from academia and industry.
    Alongside the research work, the aspect of dialogue between stakeholders on the benefits and challenges of nanotechnology is unique to Germany. Here, the cross-disciplinary work carried out by the internationally unique "NanoKommission" of the German Federal Government as part of the"NanoDialog" deserves particular mention. The open dialogue about the new technologies and new materials and the associated direct feedback of the corresponding requirements and expectations between the different interest groups helps to communicate a mutual and deeper understanding for the different requirements. As a result, the various aspects – opportunities and challenges alike – of nanotechnology can already be assessed more realistically.
    In addition to the stakeholder dialogue, it is also very important to ensure that the research into the safety of nanotechnology is made transparent to the general public by making available the relevant information in a manner which can be readily understood. Work on this aspect was started via an Internet platform conducted as part of the NanoCare project. This will now be intensively continued in the DaNa project with support from the BMBF. The DaNa project will compile existing knowledge and latest results from research projects into the safety of nanomaterials on its website. It will attempt to provide interested members of the general public with objective and easy to understand information on the subject and to engage the wider public in a factual and well-informed discussion.
    By Michael Berger. Copyright © Nanowerk

    Fonte: NanoWerk