opinion on the appropriateness of the risk assessment methodology in accordance with the Technical Guidance Documents for new and existing substances for assessing the risks of nanomaterials

Publication Date : 2007
468 Visited Entry Date : 2013/04/15


Document type Report
Subject Risk Assessment and Management
The Scientific Committee on Emerging and Newly Identified Health Risks of DG Sanco of the European Commission was asked, in the light of current scientific knowledge and in relation to the general information and practices of chemicals risk assessment, to assess the appropriateness of risk assessment methodologies described in the current Technical Guidance Documents of the chemicals legislation for the risk assessment of nanomaterials, and to provide suggestions for improvements to the methodologies.
The Committee has examined the existing base of scientific knowledge and recognised that his subject is new and rapidly developing. The Technical Guidance Documents currently make very little reference to substances in particulate form. With respect to human health, the current methodologies described in the Technical Guidance Documents are generally likely to be able to identify the hazards associated with the use of nanoparticles. For the determination of dose – response relationships, special attention should be given to the expression of the metrics of the nanoparticle dose since mass concentration is not necessarily the best description of dose for these materials and number concentration and surface area are likely to be more appropriate. Not all nanoparticle formulations have been found to induce a more pronounced toxicity than the bulk formulations of the same substance. This suggests that the evaluation of nanoparticle formulations should be carried out on a case by case basis and it is important that it is determined whether test procedures will be predictive for human health hazards for all types of nanoparticles.
With respect to environmental exposure, the validity and appropriateness of existing technologies are not always clear. In the absence of sufficient data on the fate and effect of nanoparticles on the environment, it is neither feasible nor appropriate to propose firm rules on how substances in nanoparticle form should be evaluated. Instead the applicability of existing methods for risk assessment of nanoparticles should be evaluated.
A series of recommendations for improved methodologies and areas urgently requiring additional data and scientific knowledge are presented, including observations on the applicability of in vitro test procedures, QSAR approaches to nanoparticles, the prediction of environmental concentrations, the need for new ecotoxicity tests and the assessment of bioavailability.
With respect to the performance of the risk assessment of nanomaterials, it is recommended that the staged, or tiered, approach is adopted in order to identify different adverse effects and different exposure data with nanoparticles. It is suggested that due consideration be given to the possibilities now emerging that translocation of nanoparticles away from the portal of entry may occur in humans and other species, and that the passage of nanoparticles across membranes could give rise to adverse effects, for example within the cardiovascular system or following passage across the blood – brain barrier.





3.1. General introduction     
3.2. Physicochemical properties relevant for hazard characterisation of nanoparticles     
3.2.1. Special characteristics of nanoparticles          
3.2.2. General principles for approaching nanoparticle characterisation          
3.3. Exposure assessment of nanomaterials     
3.3.1. Exposure assessment algorithm  Explanation of Terms in Figure 1        Steps in the Exposure Assessment Algorithm        Routes of Exposure                
3.3.2. Exposure control measures  Containment       Local Exhaust Ventilation (LEV)       Filtration       Personal protective equipment               
3.3.3. Exposure assessment for the environment          
3.4. Effects assessment of nanomaterials      
3.4.1. General approach          
3.4.2. Toxicokinetics  Absorption        Distribution        Metabolism        Excretion                
3.4.3. Toxicity  Reproductive toxicity and Teratogenity        Immunotoxicity        Neurotoxicity        Mutagenicity and Genotoxicity        Carcinogenicity        Diseased lungs and susceptibility to the effects of nanoparticle                
3.4.4. Ecotoxicology           
3.5. Risk characterisation of nanomaterials     
3.5.1. The difference between nanoparticles and bulk chemicals           
3.5.2. Potential risks to human health           
3.5.3. Potential risks to the environment           
3.6. Measurement methods for characterisation, exposure and effects assessment     
3.6.1. Methods for the characterisation of nanoparticles           
3.6.2. Measurement methods for exposure monitoring           
3.6.3. Methods for effects assessment for human health   In vivo studies       Instillation versus inhalation       In vitro studies               

4.1. Chapter 2 Human Health      
4.1.1. General Introduction (Section 1)          
4.1.2. Exposure Assessment (Section 2)  Workplace exposure        Consumer exposure assessment                
4.1.3. Effects Assessment (Section 3)  Evaluation of data (Section 3.2)       Dose-response assessment        Toxicokinetics        Acute toxicity (Section 3.5)       Irritation and corrosivity (Section 3.6)       Sensitisation (Section 3.7)       Repeated dose toxicity (Section 3.8)       Mutagenicity (Section 3.10 )      Carcinogenicity (Section 3.11 )      Reproductive toxicity (Section 3.12)               
4.1.4. Risk characterisation (Section 4)          
4.2. Chapter 3 Environment      
4.2.1. Section 1 General Introduction           
4.2.2. Environmental exposure assessment (Section 2)          
4.2.3. Effect assessment (Section 3)          
4.2.4. Bioavailability           
4.2.5. Bioconcentration and bioaccumulation           
4.2.6. Environmental risk assessment (Section 4)          
4.3. Conclusions and Recommendations      
4.3.1. Conclusions on Human Health Chapter          
4.3.2. Conclusions on the Environment Chapter          
4.3.3. A staged approach to the assessment of the human and environmental risks from nanomaterials.         
4.3.4. Answers to specific questions asked from SCENIHR         




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