Distribution and accumulation of UV filters (UVFs) and conservation status of Posidonia oceanica seagrass meadows in a prominent Mediterranean coastal tourist hub

• Published in: The Science of the total environment Vol. 948; p. 174784
• Main Authors: Agawin, Nona S.R., García-Márquez, Manuela Gertrudis, Espada, Diego Rita, Freemantle, Lillie, Pintado Herrera, Marina G., Tovar-Sánchez, Antonio
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20-10-2024
• Subjects: Acrylates; Alismatales; Balearic Islands; Benzophenones - analysis; Coastal tourism; Environmental Monitoring; Mediterranean Sea; Posidonia oceanica; Seagrass; Sunscreening Agents - analysis; Ultra-violet filters; Water Pollutants, Chemical - analysis; Mediterranean Sea; Balearic Islands; Seagrass; Posidonia oceanica; Coastal tourism; Ultra-violet filters; Mediterranean Sea
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.174784

This study investigates the presence and impact of UV filters in Posidonia oceanica meadows in Formentera, a Mediterranean tourist hotspot. It highlights the distribution of inorganic (TiO2 and ZnO) and organic UV filters (UVFs) in different environmental matrices, their accumulation in seagrass tissues and their impact on the seagrass health.
In the overlying and canopy waters of P. oceanica, Zn concentrations surpassed Ti, with three organic UVFs (benzophenone-3 [BP-3], avobenzone and homosalate [HMS]) consistently detected. Ti concentrations were generally higher than Zn in rhizosphere sediments, along with recurrent presence of octocrylene, HMS, 2-ethylhexyl methoxycinnamate (EHMC), and 4-methylbenzylidene camphor (4-MBC). Maximum Zn concentrations were found in canopy waters (3052.9 ng L−1). Both Ti and Zn were found in all P. oceanica tissues and leaf epiphytes across all study sites. Additional UVFs like octocrylene, avobenzone, and BP-8 were also detected in P. oceanica tissues and epiphytes. Elevated levels of octocrylene in leaf epiphytes (2112.1 ng g−1 dw) and avobenzone in leaves (364.2 ng g−1 dw) and leaf epiphytes (199.6 ng g−1 dw) were observed in the Port of La Savina, the island's main entry port. Octocrylene concentrations (up to 2575 ng g−1 dw) in rhizosphere sediments near sewage discharge points exceeded reported maxima, highlighting wastewater treatment plants as significant sources of organic UVFs. Correlational analyses suggested that the accumulation of octocrylene, avobenzone, and BP-3 negatively impacted P. oceanica's conservation status, affecting global density, density at 100 % cover, and leaf morphometry. Positive correlations were observed between leaf polyphenols (antioxidants) and concentrations of avobenzone, benzophenone-8 (BP-8), and BP-3, indicating potential oxidative stress induced by UVFs in P. oceanica.
Our study underscores the pervasive presence of UV filters in P. oceanica habitats, with implications for seagrass health and conservation, especially in areas of high tourism and sewage discharge.
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•Zn is more concentrated than Ti in canopy waters, while Ti prevails in rhizosphere sediments, indicating differential distribution.•UVFs octocrylene, avobenzone, and BP-3 can harm Posidonia oceanica, reducing density, altering leaf morphology, and causing oxidative stress responses.•High UVF near maritime traffic and sewage pipes and may impact seagrass conservation.•UVF pollution threatens seagrass habitats and urgent action required for their preservation.