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Posted: May 5, 2010
Workshop report: Risk Assessment of Manufactured Nanomaterials in a Regulatory Context
(Nanowerk News) At the 5th meeting of the Working Party on Manufactured Nanomaterials (WPMN), it was agreed to
hold an OECD Workshop on Risk Assessment of Manufactured Nanomaterials in a Regulatory Context.
The objectives of the workshop were: i) to obtain expert input into the critical issues specific for the risk
assessment of manufactured nanomaterials in a regulatory context; ii) to identify possible approaches for
risk assessment based on the current state of knowledge; and iii) to identify issues which may be addressed
through the sponsorship programme.
The workshop took place September 16th – 18th, 2009 in Washington D.C., United States, and was cohosted
by the Business and Industry Advisory Committee (BIAC) and the Society for Risk Analysis.
Seventy (70) participants representing OECD member countries, non-member economies, industries,
academia and environmental NGOs attended.
Following general presentations and discussions, case studies on Titanium dioxide nanomaterials,
Silver Nanomaterials and Carbon Nanotubes were presented. Workshop attendees then participated in one
of five parallel break-out sessions to discuss specific issues of risk assessment methodology including i)
Assessment Problem Formulation; ii) Exposure – Public, Occupational and Environment; iii) Hazard –
Human Health; iv) Ecological Toxicity and Fate; and v) Determining Risk and Linkage between
Assessment and Management.
Workshop participants concluded that the risk assessment paradigm for chemicals will continue to
guide approaches to the risk assessment of nanomaterials. However, because of the limited amount of
empirical data on nanomaterials, many of the assumptions and estimations employed in chemical risk
assessments need to be evaluated for nanomaterials. Research is also needed to determine what
characteristics of nanomaterials may pose unique hazards. In terms of the application of uncertainty factors
in risk assessments, there does not appear to be a scientific rational to justify employing a nano-specific risk
assessment uncertainty factor. Application of standard risk assessment uncertainty factors should also
undergo validation; justification should also be provided when using invalidated uncertainty factors in risk
assessments. Lastly in terms of employing units of measurement used to communicate test results used in
risk assessment, it is expected that empirical results will continue to be reported in terms of mass based
units. However, risk assessments should include a discussion of any limitations this metric may present.