Assessing UV Filter Exposure in Queensland, Australia: Human Biomonitoring Evidence Highlighting Homosalate in Children

Abstract Sunscreens are an important protection measure against harmful effects of ultraviolet radiation. However, potential health effects of several commonly used UV filters are currently being discussed. We conducted a human biomonitoring (HBM)-based exposure and risk assessment for octocrylene (OC), 2-ethylhexyl salicylate (EHS), and homosalate (HMS; a mixture of cis- and trans-HMS) in urine samples collected in Queensland and across Australia from 2012 to 2023, pooled by age, sex, and collection period (187 pools representing approximately 18,700 individuals). The pooled urines were analyzed by LC–MS/MS for specific exposure biomarkers of these UV filters. Determinants of exposure were investigated using Tobit regression. Biomarker concentrations increased over time, and clear age trends were observed, with children showing roughly one order of magnitude higher concentrations than adolescents/adults. Concentrations of the EHS biomarker 5cx-EPS exceeded the health-based guidance value (HBM-I) in 23% of children’s pooled urines. For the cis-HMS biomarker HMS-CA5, most pooled urines of children exceeded HBM-I (80%) and 53% even HBM-II. These findings indicate the need to reduce HMS exposure in at least some individuals, confirming the necessity for stricter regulations for homosalate in Australia, as recently enforced in the European Union and recommended by Australian authorities, to ensure sunscreen safety.