Nanomaterial Case Studies: Nanoscale Titanium Dioxide (External Review Draft)
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This draft document presents two case studies of nanoscale titanium dioxide (nano-TiO2) used (1) to remove arsenic from drinking water and (2) as an active ingredient in topical sunscreen. The draft case studies are organized around a comprehensive environmental assessment approach that combines a product life cycle framework with the risk assessment paradigm. The document does not draw conclusions about potential risks. Rather, the case studies are intended to help identify what needs to be known in order to conduct a comprehensive environmental assessment of the potential risks related to nano-TiO2. This draft document is part of a process that will inform the development of EPA’s research strategy to support nanomaterial risk assessments.
The case studies are organized around the comprehensive environmental assessment (CEA) approach, which combines a product life-cycle framework with the risk assessment paradigm. Risk assessment relates exposure and effects information for a substance or stressor; CEA expands on this paradigm by including life-cycle stages and considering both direct and indirect ramifications of the substance or stressor. Each chapter includes a list of questions that reflect information gaps in that portion of the document. Some of these information gaps or research needs are specific to the respective uses of nano-TiO2 either as a water treatment agent or as an ingredient in topical sunscreen. Other research needs may apply more broadly to nano-TiO2 irrespective of its application, and still other needs may apply even more widely to nanomaterials in general.
Readers are encouraged to consider the questions listed throughout the document and offer specific comments on how individual questions, or research needs, might be better expressed. If additional questions should be included or if information is already available to address some of the questions posed here, readers are also encouraged to provide such comments as well. These and other comments should be submitted as explained below under Additional Information.
|Feb 2007||EPA’s Nanotechnology White Paper recommends the development of case studies to identify unique risk assessment considerations and research needed to support risk assessment efforts for nanomaterials.|
|Mar 2007||Conducted internal review of first case study draft document.|
|Nov 2007||Conducted external peer consultation on first case study draft document.|
|Dec 2007||Conducted internal review of second case study draft document.|
|2008 - 2009||Revised case studies and combined into one draft document.|
|Jul 2009||EPA released the external review draft for public review and comment.|
|Apr 2010||EPA conducted an independent external peer review of the draft case studies document.|
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