title: A weight-of-evidence approach to identify nanomaterials in consumer products: a case study of nanoparticles in commercial sunscreens.
abstract: Nanoscale ingredients in commercial products represent a point of emerging environmental concern due to recent findings that correlate toxicity with small particle size. A weight-of-evidence (WOE) approach based upon multiple lines of evidence (LOE) is developed here to assess nanomaterials as they exist in consumer product formulations, providing a qualitative assessment regarding the presence of nanomaterials, along with a baseline estimate of nanoparticle concentration if nanomaterials do exist. Electron microscopy, analytical separations, and X-ray detection methods were used to identify and characterize nanomaterials in sunscreen formulations. The WOE/LOE approach as applied to four commercial sunscreen products indicated that all four contained at least 10% dispersed primary particles having at least one dimension <100 nm in size. Analytical analyses confirmed that these constituents were comprised of zinc oxide (ZnO) or titanium dioxide (TiO2). The screening approaches developed herein offer a streamlined, facile means to identify potentially hazardous nanomaterial constituents with minimal abrasive processing of the raw material.
authors.affiliation: Environmental Laboratory, US Army Corps of Engineers, Engineer Research and Development Center, Vicksburg, Mississippi, USA.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Cuddy
authors.affiliation: Environmental Laboratory, US Army Corps of Engineers, Engineer Research and Development Center, Vicksburg, Mississippi, USA.
authors.forename: Aimee R
authors.initials: AR
authors.lastname: Poda
authors.affiliation: Geotechnical and Structures Laboratory, US Army Corps of Engineers, Engineer Research and Development Center, Vicksburg, Mississippi, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Moser
authors.affiliation: Geotechnical and Structures Laboratory, US Army Corps of Engineers, Engineer Research and Development Center, Vicksburg, Mississippi, USA.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Weiss
authors.affiliation: Independent Consultant, Nyack, New York, USA.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Cairns
authors.affiliation: Environmental Laboratory, US Army Corps of Engineers, Engineer Research and Development Center, Vicksburg, Mississippi, USA.
authors.forename: Jeffery A
authors.initials: JA
authors.lastname: Steevens
mesh_terms: D006801:Humans; D053758:Nanoparticles / Q000032:analysis*; D010316:Particle Size; D013471:Sunburn / Q000517:prevention & control*; D013473:Sunscreening Agents / Q000737:chemistry*; D014025:Titanium / Q000032:analysis*; D015034:Zinc Oxide / Q000032:analysis*
chemical_list: D013473:Sunscreening Agents; C009495:titanium dioxide; D014025:Titanium; D015034:Zinc Oxide