Benzophenone-3 in Aquatic Environments: Sources, Occurrence, Toxicity and the Prospects for Microalgae-based Bioremediation

Abstract

Benzophenone-3 (BP-3), also known as oxybenzone, is a widely used organic ultraviolet filter incorporated into personal care products, cosmetics, paints and sunscreens. Its photostability, lipophilicity and slow biodegradation promote environmental persistence and facilitate its entry into aquatic systems through recreational activities and wastewater treatment plant effluents. BP-3 has been detected in wastewater, surface water, seawater, sediments, soils and remote marine environments, with reported concentrations spanning ng L-1 to mg L-1. Both BP-3 and its transformation products are biologically active, and available evidence indicates endocrine-disrupting, genotoxic, behavioural, reproductive and photosynthetic effects across humans, fish, aquatic invertebrates, corals and microalgae. Conventional wastewater treatment shows variable removal, while advanced oxidation processes can achieve high degradation under controlled conditions but may be constrained by cost, incomplete mineralisation and transformation-product formation. Biological treatment is therefore of interest as a potentially lower-cost and environmentally sustainable option. Microalgae are particularly relevant because they can remove contaminants through bioadsorption, bio-uptake and biodegradation while simultaneously supporting nutrient removal, carbon dioxide fixation and biomass production. However, direct evidence for microalgae-mediated BP-3 removal remains limited. Further work should prioritise strain screening, environmentally realistic exposure conditions, real wastewater matrices, transformation-product characterisation, mixture effects and scale-up to clarify the practical feasibility of microalgae-based BP-3 bioremediation.