Last Friday, EPA’s Office of Research and Development announced in the Federal Register a 45 day comment period for its new draft case study on the use of nanoscale TiO2 in water and sunscreens:

"Nanomaterial Case Studies: Nanoscale Titanium Dioxide in Water Treatment and in Topical Sunscreen"

FR 74,146 at 38188 (July 31, 2009).  The report focuses on two specific applications of nanoscale titanium dioxide (nano-TiO2): (i) as an agent for removing arsenic from drinking water, and (ii) as an active ingredient in topical sunscreen. The draft report is divided into five chapters:

  1. Introduction
  2. Life Cycle Stages
  3. Fate and Transport
  4. Exposure – Dose Characterization
  5. Characterization of Effects

The report is formidable in length, scope, and detail.  For those looking for some quick highlights, the report provides a great series of summaries of the existing TiO2 environmental, health, and safety literature.  For example:

  • Table 4-4 presents an overview of approximately 25 existing TiO2 skin absorption/penetration studies dating back to 1997;
  • Table 5-3 provides a summary of nano-TiO2 ecological effects; and
  • Tables 5-4 through 5-6 provide a summary of health effects of nano-TiO2 particles in mammalian animal models via dermal, oral, and respiratory exposure routes.

EPA notes that the "document is not intended to serve as a basis for risk management decision in the near term on these specific uses of nano-TiO2."  Rather, its focus is on developing necessary data for "future assessment efforts." Specifically, the "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."