Assessing the environmental impact of sunscreen TiO2 nanoparticles: An Australian case study

As countries have begun to ban certain organic UV filters, the demand for inorganic UV filters such as titanium dioxide (TiO2) and zinc oxide (ZnO) has emerged as an ‘environmentally friendly’ alternative. However, recently, their use is also under scrutiny due to the potential risks to consumers and the marine environment. Nano-TiO2 is suspected of being carcinogenic and cytotoxic, mainly because of its ability to produce reactive oxygen species (ROS), even in the absence of UV irradiation. In order to inhibit the generation of ROS, TiO2 nanoparticles are coated with an inorganic layer like aluminium hydroxide (Al(OH)3) or/and an organic layer like polydimethylsiloxane (PDMS). Despite attempts to protect the nanoparticles from external influences, the delamination/depletion rate of the protective coating when exposed to seawater or swimming pool water is still unknown. To further assess the environmental impact of nano-TiO2 on the aquatic environment, it is decisive to determine the concentration of these particles. However, until now, the quest for finding advanced analytical methods to gain substantial information about nanoparticle concentrations in different matrices has not yet succeeded. The prediction of nanoparticles in the environment is even more challenging due to numerous interactions that can occur during a nanoparticles’ life cycle. Therefore, this research aims to build a Scenario Risk Assessment Model using System Dynamics and lab experiments to identify the potential health impact of nano-TiO2 caused by recreational activities in public and private swimming pools. The expected outcome of this study has the potential to provide comprehensive and reliable information to government and community stakeholders about the risks of nano-TiO2.