Organic UV Filters in Aquatic Ecosystems: Distribution in Port Phillip Bay and Effects on Macroalgae
Creators: name: Carve Luzardo, Megan
Publisher: name: RMIT University
Year: 2024
Subjects: classificationCode: 310305
subject: Marine and estuarine ecology (incl. marine ichthyology)
classificationCode: 419999
subject: Other environmental sciences not elsewhere classified

description: Organic UV filters (OUVFs) are synthetic chemicals developed to protect against sunburn, premature skin aging, and skin cancer. They are the active ingredients in sunscreens but are also used in a range of commercial products. Due to their widespread use, OUVFs enter aquatic ecosystems, and have recently come under scrutiny for their potential to harm aquatic species, and bioaccumulate and persist in aquatic environments. Ecotoxicology studies have shown OUVFs may cause oxidative damage, disrupt endocrine activity, alter behaviour, and impair growth, development, and reproduction in various aquatic species. Concerns over the impact of OUVF-containing sunscreens have led to restrictions on their use in some tropical regions and the rise of sunscreens marketed as ‘reef-safe’. These formulations claim to avoid OUVFs considered harmful to coral reefs, however, they are not regulated.

Even with these developments, there is minimal information regarding the environmental concentrations and ecological impacts of OUVFs in Australian marine ecosystems, despite the widespread use of OUVF-containing sunscreen among its population. Furthermore, a lack of comprehensive toxicity data and environmental concentration measurements for many OUVFs
impedes accurate ecological risk assessments, the establishment of protective guidelines, and effective regulatory measures. This thesis addresses critical knowledge gaps by providing novel data on OUVF concentrations in Port Phillip Bay and assessing toxicity in previously unstudied aquatic species.

Chapter 2 (scientometric analysis) and Chapter 3 (systematic review) provide a comprehensive overview of the research field, and a synthesis of research on OUVF toxicity to aquatic species. Chapter 3 covers the effects of 39 OUVFs on 70 aquatic species and assesses the risk to aquatic environments by calculating predicted no-effect concentrations for 22 OUVFs and risk quotients for 12 OUVFs.

A new method of salting‐out assisted liquid–liquid extraction (SALLE) coupled with liquid-chromatography tandem mass spectrometry (LC-MS/MS) was developed for simultaneous extraction, separation, and quantification of seven OUVFs (2,4-
dihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 4-Methylbenzylidene camphor (4-MBC), butyl-methoxy-dibenzoyl methane (B-MDM), octocrylene (OCT), ethylhexyl methoxycinnamate (EHMC), and oxybenzone (BP-3)) (Chapter 4). The method showed good accuracy (69-127% recovery) and precision (&lt;6% RSD), with method detection limits of 0.011- 0.045 μg/L and predicted quantification limits (PQLs) of 0.033 - 0.135 μg/L. Environmental water samples were collected from 19 sites in Port Phillip Bay (PPB), Victoria, in summer, with temporal variation studied at two locations. Concentrations of OUVFs were detected at 10 sites, with individual concentrations ranging from 0.051 - 7.968 μg/L and the maximum total concentration at a site of 8.431 μg/L. A preliminary assessment for PPB using risk quotients (RQs) calculated from maximum and median concentrations of detected OUVFs (with site concentrations &gt; PQL) and PNECs derived using the assessment factor method
(Chapter 3) indicates potential ecological risk posed by two of the studied OUVFs. Risk quotients were &gt;1 for 4-MBC (RQmax = 14.9, RQmedian = 2.5) and BP-3 (RQmax = 6.8, RQmedian = 2.3); in contrast, RQs for OCT were &lt; 1 (RQmax = 0.3, RQmedian = 0.2), suggesting lower ecological risk. For B-MDM, insufficient toxicity data in the literature prevented the calculation of a PNEC, and consequently, RQs were not determined.

Laboratory experiments were performed to assess the effects of 4-MBC, BP-3, and EHMC on species representing different trophic roles (Chapter 5). These experiments evaluated the effect of exposure on the spore fertilization and rhizoid growth of the macroalga Hormosira banksii (a primary producer), the survival of bryozoan Virididentula dentata (a consumer), and the survival of the brine shrimp Artemia salina (a consumer). BP-3 exhibited the highest toxicity to H. banksii (EC10 = 363 μg/L), while 4-MBC was most toxic to V. dentata (EC10 = 397 μg/L). Various toxicity effect estimates are presented. This study contributes new knowledge, being the first to report on the effects of OUVF on the macroalga H. banksii and a bryozoan.

A detailed study on the acute biochemical and physiological responses of the mature green macroalga Ulva lactuca to BP-3 and OCT was performed (Chapter 6). Results showed that exposure to ≥100 μg/L BP-3 or OCT altered U. lactuca’s metabolomic profiles revealing concentration- and time-dependent changes. Affected metabolic pathways primarily relating to energy metabolism, stress response, and cellular homeostasis. At 72-h, OCT reduced relative growth rate (RGR) by 16 - 28% at 300 – 27,000 μg/L and BP-3 reduced RGR by 20-70% at 100-27,000 μg/L. At environmentally relevant concentrations, U. lactuca showed resilience to short-term exposure with no significant changes in photosynthetic efficiency of photosystem II, chlorophyll concentration, and oxidative stress (malondialdehyde content). The potential for these OUVFs to disrupt cellular metabolomic processes suggests possible compromised growth and fitness under long-term exposure. The findings highlight the need for comprehensive research on chronic exposure effects across diverse macroalgal species to fully understand the
ecological impacts of OUVFs on these important marine primary producers.

This thesis advances our understanding of the potential ecological risks posed by OUVFs to Australian marine environments and marine ecosystems globally. It contributes new knowledge on the effects of the selected OUVFs to species previously unstudied in this context, and it marks the first report of OUVF occurrence in Port Phillip Bay.