Aug 5 2009
EPA is announcing a 45-day public comment period for the draft document, Nanomaterial Case Studies: Nanoscale Titanium Dioxide in Water Treatment and Topical Sunscreen (External Review Draft), as announced in the July 31, 2009 Federal Register Notice. The deadline for comments is September 14, 2009.
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.
Engineered nanoscale materials (nanomaterials) have been described in part as having at least one dimension on the order of approximately 1 to 100 nanometers (nm) and unique or novel properties that arise from their small size. This draft document is a starting point to determine what is known and what needs to be known about selected nanomaterials as part of a process to identify and prioritize research to inform future assessments of the potential ecological and health implications of these materials. Two specific applications of nanoscale titanium dioxide (nano-TiO2) are considered: as an agent for removing arsenic from drinking water and as an active ingredient in topical sunscreen. These “case studies” do not represent completed or even preliminary assessments, nor are they intended to serve as a basis for risk management decisions in the near term on these specific uses of nano-TiO2. Instead, the intent is to use this document in developing the scientific and technical information needed for future assessment efforts.
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.
History/Chronology
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. See: http://www.epa.gov/osa/pdfs/nanotech/epa-nanotechnology-whitepaper-0207.pdf
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.
Jun 2009 Conducted internal review of case studies draft document.
Jun 2009 Conducted interagency review of case studies draft document.
Jul 2009 EPA released the external review draft for public review and comment.
Next Steps
Jul-Sep 2009: The draft report will undergo external review and public comment.
Sep 29-30, 2009: An invitation-only workshop will be held to identify and prioritize research needs
Oct-Dec 2009: A report comprising the Jul 2009 draft document and a description of the process and outcomes of the workshop will be prepared for the EPA Board of Scientific Counselors to review in public session.
Mar 2010: The final version of the case studies document will be released at or about this time.