Exploring the safety of nanoparticles in Australian sunscreens

Engineered nanoparticles are now well recognised to possess a range of apparently unique and as yet under-researched toxicities Safety concerns about such nanoparticles in cosmetics such as sunscreens are fuelled by consideration of factors such as their size, high mobility in the body and unusual reactivities. Yet, published research relied upon by safety regulators suggests there are no significant adverse health effects from nanoparticle sunscreen preparations [such as those containing nanoparticulate zinc oxide (ZnO) and titanium dioxide (TiO2)] despite free radical formation in the presence of light. This is chiefly because of minimal dermal absorption of skinapplied nanoparticles below the dead and highly keratinised cells of the stratum corneum. Influential non-governmental organisations and a NSW parliamentary inquiry have expressed concern that this research has inadequately accounted for issues associated with chronic use of these sunscreens over hairy, damaged or aged skin or flexural creases. It may be time for Australian safety regulators to apply the precautionary principle in this context and increase labelling requirements about the use of nanoparticles in sunscreens.