Small scale and high impact: the leaching of hazardous elements from glitters

In response to the growing microplastic crisis, several countries have restricted the use of glitter in various products; however, it remains widely used and commercially available. While existing research has predominantly addressed the physical impacts of glitter particles, this study investigates the release of potentially toxic elements (PTEs) from their coloured and reflective layers. We characterized both natural and plastic glitters available on the market, evaluating their structure, coloration, PTEs content, and the leaching behaviour of these elements into various model solutions. The results showed that coloured and reflective glitter layers contained elevated concentrations of Al (up to 10 404 mg kg^-1), Cu (up to 2210 mg kg^-1), Cr (up to 780 mg kg^-1), and Ni (up to 10.6 mg kg^-1), whereas natural glitter was rich in Al (51 883 mg kg^-1) and Pb (3.22 mg kg^-1). The highest metal mobilisation was observed under acidic and hydrophobic conditions, exceeding 90% for Cr, Cu and Ni. Although glitter represents a relatively small fraction of plastic waste, its small particle size, irregular shape, multilayered structure, and ability to release metals indicate that it may contribute to contamination and environmental risk in aquatic and terrestrial ecosystems. The results also showed that natural alternatives cannot automatically be considered environmentally safe substitutes for plastic glitter.