Impact of acute and long-term exposure to oxybenzone on the Caenorhabditis elegans life history

UV-filters are the active ingredients providing weatherproofing to industrial products and UV-light protection in personal care products such as sun-tan lotions. Sun-tan lotions products are commonly recommended to protect the skin from the sun’s damaging rays however their increasing prevalence in drinking water and aquatic environments has raised concern regarding their effect on both human and environmental health. The common UV-filter Oxybenzone (BP-3) has been highlighted as a compound of particular concern due to its high prevalence, its known toxicity in aquatic species and its ability to accumulate in the active sludge of waste-water treatment plants. Here, we investigate for the first time the effect of BP-3 on the fecundity and growth of the terrestrial nematode Caenorhabditis elegans and develop a novel method of modelling the UV-filter pollution associated with the use of UV-filter contaminated active sludge as fertilizer. Our results show that four hour BP-3 exposure did not affect reproductive health at environmentally relevant concentrations (experimental concentrations of 50, 100, 250 and 500 μg/L) however, two of three replicates demonstrated a significant effect of BP-3 (experimental concentrations of 500, 1000, 1500, 2000 μg/L) on total C. elegans fecundity. One replicate also demonstrated that nematodes acutely exposed to 500 μg/L of BP-3 were significantly larger than those measured before the experiment, potentially suggesting an effect on the nematodes ability to control osmolarity. It was found that BP-3 did not influence the growth of C.elegans, which contradicts previous research. This highlights the need for further investigation into BP-3 toxicity. Finally, it was found that in one of the replicates, the nematodes exposed to E. coli contaminated with 1500 μg/L BP-3 were significantly smaller than those exposed to E. coli contaminated with 1000 μg/L BP-3,suggesting the need for further investigation into the potential environmental risks associated with UV-filter pollution originating from active sludge. In conclusion the research conducted in this project provides a novel insight into BP-3 toxicity and the development of a universal toxicity model, which could provide reasoning for the implementation of restrictions on dangerous UV-filters both in localised areas but also internationally.