Impact of inorganic UV filters contained in sunscreen products on tropical stony corals (Acropora spp.)

Inorganic UV filter-based sunscreens labelled as eco-friendly threaten sea urchin populations

Although the negative effects of inorganic UV filters have been documented on several marine organisms, sunscreen products containing such filters are available in the market and proposed as eco-friendly substitutes for harmful, and already banned, organic UV filters (e.g. octinoxate and oxybenzone). In the present study, we investigated the effects of four sunscreen products, labelled by cosmetic companies as "eco-friendly", on the early developmental stages of the sea urchin Paracentrotus lividus, a keystone species occurring in vulnerable coastal habitats. Among sunscreens tested, those containing ZnO and TiO2 or their mix caused severe impacts on sea urchin embryos. We show that inorganic UV filters were incorporated by larvae during their development and, despite the activation of defence strategies (e.g. phagocytosis by coelomocytes), generated anomalies such as skeletal malformations and tissue necrosis. Conversely, the sunscreen product containing only new-generation organic UV filters (e.g. methylene bis-benzotriazolyl tetramethyl, ethylhexyl triazone, butylphenol diethylamino hydroxybenzoyl hexyl benzoate) did not affect sea urchins, thus resulting actually eco-compatible. Our findings expand information on the impact of inorganic UV filters on marine life, corroborate the need to improve the eco-friendliness assessment of sunscreen products and warn of the risk of bioaccumulation and potential biomagnification of inorganic UV filters along the marine food chain.

Nanomaterials in the environment and their pragmatic voyage at various trophic levels in an ecosystem

In the development of nanotechnology, nanomaterials (NMs) have a huge credential in advancing the existing follow-ups of analytical and diagnosis techniques, drug designing, agricultural science, electronics, cosmetics, sports, textiles and water purification. However, NMs have also grasped attention of researchers onto their toxicity. In the present review, initially the development of notable NMs such as metal and metal-oxide nanoparticles (NPs), magnetic NPs, carbon-based NMs and quantum dots intended to be commercialized along with their applications are discussed. This is followed by the current scenario of NMs in the environment to widen the outlook on the concentration of NPs in the environmental compartments and the frequency of organism exposed to NPs at varied trophic levels. In order to understand the physiochemical and morphological significance of NPs in exhibiting toxicity, fate of NPs in the environment is briefly deliberated. This is further geared-up to glance in-sightedly on the organisms starting from primary producer to primary consumer, secondary consumer, tertiary consumer and decomposers encountering NPs in their habitual niche. The state of NPs to which organisms are exposed, mechanism of NP uptake and toxicity, anomalies faced at each trophic level, concentration of NPs that is liable to cause toxicity and, biotransfer of NPs to the next generation and trophic level are detailed. Finally, the future prospects on bioaccumulation and biomagnification of NP-based products are conversed. Thus, the review would be noteworthy in unveiling the significance of NPs in forthcoming years combined with threat towards each organism in an ecosystem.

Changes in life history parameters and expression of key genes of Brachionus plicatilis exposed to a combination of organic and inorganic ultraviolet filters

The increasing use of ultraviolet filters has become an emerging contaminant on the coast, posing potential ecological risks. Rotifers are essential components of marine ecosystems, serving as an association between primary producers and higher-level consumers. These organisms frequently encounter ultraviolet filters in coastal waters. This study aimed to assess the comprehensive effects of organic ultraviolet filters, specifically 2-ethylhexyl-4-methoxycinnamate (EHMC), and inorganic ultraviolet filters, namely, titanium dioxide nanoparticles (TiO2 NPs), on the rotifer Brachionus plicatilis. We exposed B. plicatilis to multiple combinations of different concentrations of EHMC and TiO2 NPs to observe changes in life history parameters and the expression of genes related to reproduction and antioxidant responses. Our findings indicated that increased EHMC concentrations significantly delayed the age at first reproduction, reduced the total offspring, and led to considerable alterations in the expression of genes associated with reproduction and stress. Exposure to TiO2 NPs resulted in earlier reproduction and decreased total offspring, although these changes were not synchronised in gene expression. The two ultraviolet filters had a significant interaction on the age at first reproduction and the total offspring of rotifer, with these interactions extending to the first generation. This research offers new insights into the comprehensive effects of different types of ultraviolet filters on rotifers by examining life history parameters and gene expression related to reproduction and stress, highlighting the importance of understanding the impacts of sunscreen products on zooplankton health.

Ultraviolet Filters: Dissecting Current Facts and Myths

Skin cancer is a global and increasingly prevalent issue, causing significant individual and economic damage. UV filters in sunscreens play a major role in mitigating the risks that solar ultraviolet ra-diation poses to the human organism. While empirically effective, multiple adverse effects of these compounds are discussed in the media and in scientific research. UV filters are blamed for the dis-ruption of endocrine processes and vitamin D synthesis, damaging effects on the environment, induction of acne and neurotoxic and carcinogenic effects. Some of these allegations are based on scientific facts while others are simply arbitrary. This is especially dangerous considering the risks of exposing unprotected skin to the sun. In summary, UV filters approved by the respective governing bodies are safe for human use and their proven skin cancer-preventing properties make them in-dispensable for sensible sun protection habits. Nonetheless, compounds like octocrylene and ben-zophenone-3 that are linked to the harming of marine ecosystems could be omitted from skin care regimens in favor of the myriad of non-toxic UV filters.

Sunscreens and micro(nano)plastics: Are we aware of these threats to the Egyptian coral reefs?

During a snorkeling trip to Marsa Alam and Hamata (southern Red Sea Riviera, Egypt) I explored the coral reefs and the diverse marine habitats of fish and invertebrate species. The area invites recreational diving and snorkeling, but the beaches are littered with all sorts of solid waste (mainly fragmented plastics). Also, there are no local restrictions on sunscreen use. The development of tourism to the area raises questions about the environmental impact and how its further growth will have on coral reefs. Every year, 1.2 million tourists visit the Red Sea coast (about 3287 tourists per day) and release about 1.7 tons/month of sunscreen into the Red Sea. As an ecologist and editorial board member of Science of the Total Environment, I ask myself how we as scientists can increase public awareness and call for prompt actions to protect the coral reefs. The discussion underlines two major threats to the Egyptian coral reefs: sunscreen use and micro(nano)plastics waste. The discussion closes with possible solutions, future perspectives, and recommendations to protect the coral reefs ecosystem of the Egyptian Red Sea.

A broad-taxa approach as an important concept in ecotoxicological studies and pollution monitoring

Aquatic invertebrates play a pivotal role in (eco)toxicological assessments because they offer ethical, cost-effective and repeatable testing options. Additionally, their significance in the food chain and their ability to represent diverse aquatic ecosystems make them valuable subjects for (eco)toxicological studies. To ensure consistency and comparability across studies, international (eco)toxicology guidelines have been used to establish standardised methods and protocols for data collection, analysis and interpretation. However, the current standardised protocols primarily focus on a limited number of aquatic invertebrate species, mainly from Arthropoda, Mollusca and Annelida. These protocols are suitable for basic toxicity screening, effectively assessing the immediate and severe effects of toxic substances on organisms. For more comprehensive and ecologically relevant assessments, particularly those addressing long-term effects and ecosystem-wide impacts, we recommended the use of a broader diversity of species, since the present choice of taxa exacerbates the limited scope of basic ecotoxicological studies. This review provides a comprehensive overview of (eco)toxicological studies, focusing on major aquatic invertebrate taxa and how they are used to assess the impact of chemicals in diverse aquatic environments. The present work supports the use of a broad-taxa approach in basic environmental assessments, as it better represents the natural populations inhabiting various ecosystems. Advances in omics and other biochemical and computational techniques make the broad-taxa approach more feasible, enabling mechanistic studies on non-model organisms. By combining these approaches with in vitro techniques together with the broad-taxa approach, researchers can gain insights into less-explored impacts of pollution, such as changes in population diversity, the development of tolerance and transgenerational inheritance of pollution responses, the impact on organism phenotypic plasticity, biological invasion outcomes, social behaviour changes, metabolome changes, regeneration phenomena, disease susceptibility and tissue pathologies. This review also emphasises the need for harmonised data-reporting standards and minimum annotation checklists to ensure that research results are findable, accessible, interoperable and reusable (FAIR), maximising the use and reusability of data. The ultimate goal is to encourage integrated and holistic problem-focused collaboration between diverse scientific disciplines, international standardisation organisations and decision-making bodies, with a focus on transdisciplinary knowledge co-production for the One-Health approach.

Exposure to pentachlorophenol destructs the symbiotic relationship between zooxanthellae and host and induces pathema in coral Porites lutea

Stress from chemical pollutants is among the key issues that have adverse impacts on coral reefs. As a persistent organic pollutant, pentachlorophenol (PCP) has been detected in the seawater of Weizhou Island and was proved to have significant adverse effects on aquatic animals. However, little is known about its effects on scleractinian coral. Therefore, we investigated the response of the coral Porites lutea to PCP stress. Coral bleaching, photosynthesis parameters and antioxidant enzyme activities of P. lutea under PCP exposure were documented. After 96 h of exposure, significant tissue loss and bleaching occurred when the PCP concentration exceeded 100 μg/L. The density of symbiotic zooxanthellae decreased from 2.06 × 106 cells/cm2 to 0.93 × 106 cells/cm2 when the PCP concentration increased from 1 μg/L- 1000 μg/L. Long-term exposure of 120 days to PCP at 0.1 μg/L also led to coral bleaching, the maximum photochemical quantum yield of PSII in P. lutea nubbins significantly decreased to 0.482. The analysis of microbial community distribution indicated that the increase of the pathogenic bacterium Citrobacter may be one of the inducers of coral bleaching. Conjoint analysis of transcriptomics and proteomics showed that the metabolism of amino acids and carbohydrates in zooxanthellae was abnormal, leading to the destruction of its symbiotic relationship with the host. The immune system of the host was disrupted, which could be linked to the prevalence of coral pathema. The toxic responses of PCP on both zooxanthellae and its host were further confirmed by the upregulation of the differential metabolites including 1-naphthylamine and phosphatidylcholine, etc.

Physiological impact of personal care product constituents on non-target aquatic organisms

Personal care products (PCPs) are products used in cleaning, beautification, grooming, and personal hygiene. The rise in diversity, usage, and availability of PCPs has resulted in their higher accumulation in the environment. Thus, these constitute an emerging category of environmental contaminants due to the potential of its constituents (chemical and non-chemical) to induce various physiological effects even at lower concentrations (ng/L). For analyzing the impact of the PCPs constituents on the non-target organism about 300 article including research articles, review articles and guidelines were studied from 2000 to 2023. This review aims to firstly discuss the fate and accumulation of PCPs in the aquatic environment and organisms; secondly provides overview of environmental risks that are linked to PCPs; thirdly review the trends, current status of regulations and risks associated with PCPs and finally discuss the knowledge gaps and future perspectives for future research. The article discusses important constituents of PCPs such as antimicrobials, cleansing agents and disinfectants, fragrances, insect repellent, moisturizers, plasticizers, preservatives, surfactants, UV filters, and UV stabilizers. Each of them has been found to display certain toxic impact on the aquatic organisms especially the plasticizers and UV filters. These continuously and persistently release biologically active and inactive components which interferes with the physiological system of the non-target organism such as fish, corals, shrimps, bivalves, algae, etc. With a rise in the number of toxicity reports, concerns are being raised over the potential impacts of these contaminant on aquatic organism and humans. The rate of adoption of nanotechnology in PCPs is greater than the evaluation of the safety risk associated with the nano-additives. Hence, this review article presents the current state of knowledge on PCPs in aquatic ecosystems.

Insights on the UV-Screening Potential of Marine-Inspired Thiol Compounds

One of the major threats to skin aging and the risk of developing skin cancer is excessive exposure to the sun's ultraviolet radiation (UVR). The use of sunscreens containing different synthetic, organic, and inorganic UVR filters is one of the most widespread defensive measures. However, increasing evidence suggests that some of these compounds are potentially eco-toxic, causing subtle damage to the environment and to marine ecosystems. Resorting to natural products produced in a wide range of marine species to counteract UVR-mediated damage could be an alternative strategy. The present work investigates marine-inspired thiol compounds, derivatives of ovothiol A, isolated from marine invertebrates and known to exhibit unique antioxidant properties. However, their potential use as photoprotective molecules for biocompatible sunscreens and anti-photo aging formulations has not yet been investigated. Here, we report on the UVR absorption properties, photostability, and in vitro UVA shielding activities of two synthetic ovothiol derivatives, 5-thiohistidine and iso-ovothiol A, by spectrophotometric and fluorimetric analysis. We found that the UVA properties of these compounds increase upon exposure to UVA and that their absorption activity is able to screen UVA rays, thus reducing the oxidative damage induced to proteins and lipids. The results of this work demonstrate that these novel marine-inspired compounds could represent an alternative eco-friendly approach for UVR skin protection.

Are Physical Sunscreens Safe for Marine Life? A Study on a Coral-Zooxanthellae Symbiotic System

Limited toxic and ecological studies were focused on physical sunscreen that is considered to have "safer performance", in which nanosize zinc oxide (nZnO) and nanosize titanium dioxide (nTiO2) generally are added as ultraviolet filters. Herein, the common button coral Zoanthus sp. was newly used to assess the toxic effects and underlying mechanisms of physical sunscreen. Results showed that physical sunscreen induced severe growth inhibition effects and largely compelled the symbiotic zooxanthellae, indicating that their symbiotic systems were threatened and, also, that neural and photosynthesis functions were influenced. Zn2+ toxicity and bioaccumulation were identified as the main toxic mechanisms, and nTiO2 particles released from physical sunscreen also displayed limited bioattachment and toxicity. Oxidative stress, determined by increased reactive oxygen species, superoxide dismutase, and malondialdehyde content, was indicated as another important toxic mechanism. Furthermore, when Zoanthus sp. was restored, the inhibited individual coral could be largely recovered after a short (3 d) exposure time; however, a longer exposure time damaged the coral irretrievably, which revealed the latent environmental risks of physical sunscreen. This study investigated the toxic effect of physical sunscreen on Zoanthus sp. in a relatively comprehensive manner, thus providing new insights into the toxic response of sunscreen on marine organisms.

Acute toxicity assessment of nine organic UV filters using a set of biotests

UV filters in environmental compartments are a source of concern related to their ecotoxicological effects. However, little is known about UV filters' toxicity, particularly those released into the environment as mixtures. Acute toxicity of nine organic UV filters benzophenone-1, benzophenone-2, benzophenone-3, 4-methoxy benzylidene camphor, octocrylene, ethylhexyl methoxycinnamate, 2-ethylhexyl salicylate, homosalate, and butyl methoxydibenzoylmethane was determined. UV filter solutions were tested as single, binary, and ternary mixtures of various compositions. Single solutions were tested using a set of bio tests, including tests on saline crustaceans (Artemia franciscana), freshwater crustaceans (Daphnia magna), marine bacteria (Aliivibrio fischeri), and freshwater plants (Lemna minor). The tests represent different stages of the trophic chain, and hence their overall results could be used to risk assessment concerning various water reservoirs. The toxicity of binary and ternary mixtures was analyzed using the standardized Microtox® method. Generally, organic UV filters were classified as acutely toxic. Octocrylene was the most toxic for Arthemia franciscana (LC50 = 0.55 mg L-1) and Daphnia magna (EC50 = 2.66-3.67 mg L-1). The most toxic against freshwater plants were homosalate (IC50 = 1.46 mg L-1) and octocrylene (IC50 = 1.95 mg L-1). Ethylhexyl methoxycinnamate (EC50 = 1.38-2.16 mg L-1) was the most toxic for marine bacteria. The least toxic for crustaceans and plants were benzophenone-1 (EC50 = 6.15-46.78 mg L-1) and benzophenone-2 (EC50 = 14.15-54.30 mg L-1), while 4-methoxy benzylidene camphor was the least toxic for marine bacteria (EC50 = 12.97-15.44 mg L-1). Individual species differ in their sensitivity to the tested organic UV filters. An assessment of the toxicity of mixtures indicates high and acute toxicity to marine bacteria after exposition to a binary mixture of benzophenone-2 with octocrylene, 2-ethylhexyl salicylate, or homosalate. The toxicity of mixtures was lower than single solutions predicting antagonistic interaction between chemicals.

Graphical abstract

The effects of UV filters on health and the environment

Sunscreens are an important means of protection against sunburns, dyspigmentation, photoaging, and photocarcinogenesis. Sunscreens come in a variety of formulations that can protect against ultraviolet B (UVB) radiation, both UVB and ultraviolet A (UVA) radiation (broad-spectrum sunscreens), and UVB, UVA, and visible light (tinted broad-spectrum sunscreens). In the USA, there is currently a paucity of FDA-approved broad-spectrum filters on the market. Studies have identified the presence of multiple UV filters in water sources globally. Many laboratory studies have implicated the potential impact of UV filters on coral reef bleaching, the food chain, and human health. However, many of these studies are performed at concentrations that are much higher than those present in the natural environment. With increasing discussion surrounding the role of organic and inorganic UV filters as potential environmental pollutants over the past decade, approval of additional broad-spectrum filters would be an important means of alleviating the use of more controversial filters. The aim of this article is to review the effects of UV filters on health and the environment and explore potential adjunctive agents for photoprotection.

Single-Particle ICP-MS/MS Application for Routine Screening of Nanoparticles Present in Powder-Based Facial Cosmetics

The short- and long-term impacts of nanoparticles (NPs) in consumer products are not fully understood. Current European Union (EU) regulations enforce transparency on products containing NPs in cosmetic formulations; however, those set by the U.S. Food and Drug Administration are lacking. This study demonstrates the potential of single-particle inductively coupled plasma tandem mass spectrometry (spICP-MS/MS) as a screening method for NPs present in powder-based facial cosmetics (herein referred to as FCs). A proposed spICP-MS/MS method is presented along with recommended criteria to confirm particle presence and particle detection thresholds in seven FCs. FC products of varying colors, market values, and applications were analyzed for the presence of Bi, Cr, Mg, Mn, Pb, Sn, Ag, Al, and Zn NPs based on their ingredient lists as well as those commonly used in cosmetic formulations. The presence of NPs smaller than 100 nm was observed in all FC samples, and no correlations with their presence and market value were observed. Here, we report qualitative and semi-quantitative results for seven FC samples ranging in color, brand, and shimmer.

Bioconcentration and cellular effects of emerging contaminants in sponges from Maldivian coral reefs: A managing tool for sustainable tourism

Tourism is the main income source for the Maldives, but concurrently, it represents a growing threat to its marine ecosystem. Here, we monitored the bioaccumulation of 15 emerging contaminants (ECs) in the Maldivian reef sponges Spheciospongia vagabunda collected in two resort islands (Athuruga and Thudufushi, Ari Atoll) and an inhabited island (Magoodhoo, Faafu Atoll), and we analysed their impact on different sponge cellular stress biomarkers. Caffeine and the insect repellent DEET were detected in sponges of all the islands, whereas the antibiotic erythromycin and the UV filter 4-methylbenzylidene camphor were found in resort islands only. Although concentrations were approximately a few ng/g d.w., we quantified various induced cellular effects, in particular an increase of the levels of the enzyme glutathione S-transferase involved in cell detoxification. Our results highlight the importance to increase awareness on ECs pollution, promoting the use of more environmental friendly products to achieving the sustainable development goals.

Alterations induced by titanium dioxide nanoparticles (nano-TiO2) in fertilization and embryonic and larval development of the tropical sea urchin Lytechinus variegatus

The release of nanomaterials into the environment is the cause of an emerging concern. Titanium dioxide nanoparticles (nano-TiO₂) among the most produced nanomaterials, has been documented in marine coastal areas posing a threat on marine biota. Sea urchin embryos are recognized as suitable bioindicators in ecological risk assessment and recently for nanomaterials. This study investigated the impact of nano-TiO₂ on fertilization, embryonic and larval development of the tropical sea urchin Lytechinus variegatus in a range of concentrations (0.005-5 μg/mL) which includes environmentally relevant ones. The behavior of nano-TiO₂ in tropical natural seawater was determined by dynamic light scattering (DLS) and toxicity was evaluated through fertilization and embryotoxicity tests, and morphological/morphometric analyses of sea urchin's larvae. Limited toxicity was recorded for nano-TiO₂ in tropical sea urchin embryos and larvae, except for effects at the gastrula stage at 0.005 μg/mL. Large agglomerates of nano-TiO₂ (5 μg/mL) were observed adhering onto sea urchin larvae thus probably preventing nanoparticles uptake at the highest concentrations (>0.005 μg/mL). Environmental levels of nano-TiO₂ are able to cause toxicity on tropical sea urchin L. variegatus embryos with potential consequences on populations and their ecological role in tropical coastal areas.

The response of aquatic ecosystems to the interactive effects of stratospheric ozone depletion, UV radiation, and climate change

Variations in stratospheric ozone and changes in the aquatic environment by climate change and human activity are modifying the exposure of aquatic ecosystems to UV radiation. These shifts in exposure have consequences for the distributions of species, biogeochemical cycles, and services provided by aquatic ecosystems. This Quadrennial Assessment presents the latest knowledge on the multi-faceted interactions between the effects of UV irradiation and climate change, and other anthropogenic activities, and how these conditions are changing aquatic ecosystems. Climate change results in variations in the depth of mixing, the thickness of ice cover, the duration of ice-free conditions and inputs of dissolved organic matter, all of which can either increase or decrease exposure to UV radiation. Anthropogenic activities release oil, UV filters in sunscreens, and microplastics into the aquatic environment that are then modified by UV radiation, frequently amplifying adverse effects on aquatic organisms and their environments. The impacts of these changes in combination with factors such as warming and ocean acidification are considered for aquatic micro-organisms, macroalgae, plants, and animals (floating, swimming, and attached). Minimising the disruptive consequences of these effects on critical services provided by the world's rivers, lakes and oceans (freshwater supply, recreation, transport, and food security) will not only require continued adherence to the Montreal Protocol but also a wider inclusion of solar UV radiation and its effects in studies and/or models of aquatic ecosystems under conditions of the future global climate.

On the Fate of Butyl Methoxydibenzoylmethane (Avobenzone) in Coral Tissue and Its Effect on Coral Metabolome

The intensive use of sunscreen products has raised concerns regarding their environmental toxicity and the adverse impacts of ultraviolet (UV) filters on ecologically important coral communities. Prior metabolomic analyses on symbiotic coral Pocillopora damicornis exposed to the UV filter butyl methoxydibenzoylmethane (BM, avobenzone) revealed unidentified ions in the holobiont metabolome. In the present study, follow-up differential metabolomic analyses in BM-exposed P. damicornis detected 57 ions with significantly different relative concentrations in exposed corals. The results showed an accumulation of 17 BM derivatives produced through BM reduction and esterification. The major derivative identified C16:0-dihydroBM, which was synthesized and used as a standard to quantify BM derivatives in coral extracts. The results indicated that relative amounts of BM derivatives made up to 95% of the total BM (w/w) absorbed in coral tissue after 7 days of exposure. Among the remaining metabolites annotated, seven compounds significantly affected by BM exposure could be attributed to the coral dinoflagellate symbiont, indicating that BM exposure might impair the photosynthetic capacity of the holobiont. The present results suggest that the potential role of BM in coral bleaching in anthropogenic areas should be investigated and that BM derivatives should be considered in future assessments on the fate and effects of BM in the environment.

Environmental impacts of the ultraviolet filter oxybenzone

Organic UV filters are emerging contaminants with increasing evidence of their negative impact on environmental health and water quality. One of the most common and environmentally relevant organic UV filters is oxybenzone (OBZ). While much of the initial focus has been on investigating the interaction of OBZ with coral reefs, there have been several recent studies that indicate that organic UV filters are affecting other environmental endpoints, including marine animals, algae, and plants. OBZ has been found to bioaccumulate in marine animals such as fish and mussels and then potentially acting as an endocrine disruptor. In plants, exposure to OBZ has been associated with decreased photosynthesis, inhibited seed germination, and impaired plant growth. In this review, we summarize the current state of knowledge regarding the environmental impacts of OBZ and suggest potential future directions.

The Impact of Flavonoid-Loaded Nanoparticles in the UV Protection and Safety Profile of Topical Sunscreens

Excessive UV radiation exposure is harmful to skin cells since sunburn is accompanied by oxidative burst, leading to a rapid increase in skin cancer. However, the insufficient UV photoprotection of approved sunscreens and the negative impact of their compositions on ecosystems and human health makes the utility of sunscreen a questionable recommendation. Therefore, discovering UV filters with significant antioxidant activity and improved topical performance and photostability is an urgent need. Recently, the use of nanosized natural molecules incorporated in sunscreens has been a scientific hot topic, as it has been suggested that they provide a synergistic effect with synthetic UV filters, improving overall SPF and antioxidant activity, higher retention on the epidermis, and less toxicity. The aim of this review was to verify the usefulness of sunscreens incorporating flavonoid-loaded nanoparticles. A literature review was performed, where original and review articles published in the last 6 years were analyzed. Formulations containing nanosized flavonoids with improved UVA photoprotection and safer toxicological profiles, associated or not with synthetic filters, are promising sunscreens and more clinical investigation must be performed to validate these findings.

Calcium phosphates from fish bones in sunscreen: An LCA and toxicity study of an emerging material for circular economy

The use of sustainable and natural materials is an ever-increasing trend in cosmetic. Natural calcium phosphate (CaP-N) from food by-products and especially from fisheries (i.e., bones), has been suggested as a sustainable option to chemicals commonly used in cosmetic products, in particular to UV-filters in sunscreens. However, the environmental benefits and impacts of its production and use are still uncertain as they have never been quantified. In this paper, we report on toxicological characterization of CaP-N produced from incineration of fish meal in a pilot scale plant. Furthermore, we quantified the environmental burdens linked to the partial substitution of UV-filters by CaP-N through the life cycle assessment (LCA) comparing CaP-N with zinc oxide nanoparticles (ZnO NPs) as alternative option. CaP-N consists in a biphasic mixture 53:47 of hydroxyapatite:β-tricalcium phosphate, and is made of round particles with a diameter in the range of a few microns. Toxicity tests on 4 aquatic species (Dunaliella tertiolecta, Tigriopus fulvus, Corophium insidiosum and Gammarus aequicauda) revealed that CaP-N does not produce any adverse effect, all the species showing EC/LC50 values higher than 100 mg L^-1. Moreover, during the 96 h acute toxicity test on C. insidiosum, which is a tube-building species, the specimens built their tubes with the available CaP-N, further attesting the non-toxicity of the material. The LCA study showed that the environmental performance of CaP-N is better than that of ZnO NPs for 11 out of 16 impact categories analysed in this study, especially for the categories Ecotoxicity and Eutrophication of freshwaters (an order of magnitude lower), and with the exception of fossil resources for which CaP-N has a significantly higher impact than ZnO NPs (+140 %). Concluding, our study demonstrates that the replacement of ZnO NPs with CaP-N thermally extracted from fish bones in cosmetic products can increase their safety and sustainability.

Target and Nontarget Screening of Organic Chemicals and Metals in Recycled Plastic Materials

Increased demand for recycling plastic has prompted concerns regarding potential introduction of hazardous chemicals into recycled goods. We present a broad screening of chemicals in 21 plastic flake and pellet samples from Canadian recycling companies. From target analysis, the organophosphorus ester flame retardants and plasticizers exhibited the highest detection frequencies (DFs) (5-100%) and concentrations (<DL-4,700 ng/g), followed by brominated/chlorinated flame retardants (<DL-2,150 ng/g, 5-76% DFs). The perfluoroalkyl acids were least detected at the lowest concentrations (<0.01-0.70 ng/g, 5-19% DFs). Using nontargeted analysis, 217 chemicals were identified as Level 1 (authentic standard) or 2 (library match), with estimated individual concentrations up to 1030 ng/g (highest: 2-hexyl hydroxy benzoate, 100% DF). Total (Σ60) element concentrations were between 0.005 and 2,980 mg/kg, with highest concentrations for calcium (2,980 mg/kg), sodium (617 mg/kg), and iron (156 mg/kg). Collectively >280 chemicals were detected in recycled plastic pellets and flakes, suggesting potential incorporation into recycled goods. Individual concentrations indicate unintentional trace contamination following European Union threshold limits for recycled granules (500 mg/kg) and waste plastic flakes (1,000 mg/kg), although do not reflect toxicological thresholds, if any. Our study highlights that while recycling addresses sustainability goals, additional screening of goods and products made from recycled plastics is needed to fully document potentially hazardous chemicals and exposure.

Sunscreen exposure interferes with physiological processes while inducing oxidative stress in seagrass Posidonia oceanica (L.) Delile

The effects of a commercial sunscreen mixture on the Mediterranean seagrass Posidonia oceanica were investigated, evaluating its response in physiological processes and biochemical indicators of oxidative stress. Short-term laboratory experiments were conducted recreating summer conditions, and two sunscreen concentrations were tested in whole P. oceanica plants placed inside aquaria. Although primary productivity of leaf segments seemed to benefit from sunscreen addition, probably due to inorganic nutrients released, the rest of the biological parameters reflected possible impairments in the overall functioning of P. oceanica as a result of oxidative damages. Chlorophyll production and nitrogen fixation associated with old leaves were inhibited under high sunscreen concentrations, which concurred with elevated reactive oxygen species production, catalase activity and polyphenols content in the seagrass leaves. These results emphasize the importance of directing future investigations on determining which specific components of sunscreen products are likely threatening the wellbeing of critical species, such as P. oceanica.

Zinc and Zinc Transporters in Dermatology

Zinc is an important trace mineral in the human body and a daily intake of zinc is required to maintain a healthy status. Over the past decades, zinc has been used in formulating topical and systemic therapies for various skin disorders owing to its wound healing and antimicrobial properties. Zinc transporters play a major role in maintaining the integrity of the integumentary system by controlling zinc homeostasis within dermal layers. Mutations and abnormal function of zinc-transporting proteins can lead to disease development, such as spondylocheirodysplastic Ehlers-Danlos syndrome (SCD-EDS) and acrodermatitis enteropathica (AE) which can be fatal if left untreated. This review discusses the layers of the skin, the importance of zinc and zinc transporters in each layer, and the various skin disorders caused by zinc deficiency, in addition to zinc-containing compounds used for treating different skin disorders and skin protection.

Assessing the eco-compatibility of new generation sunscreen products through a combined microscopic-molecular approach

There is now unequivocal evidence that sunscreen can severely affect marine ecosystems. However, so far, most studies have focused on the impact of single sunscreen ingredients rather than on the whole sunscreen products, which are released into the marine environment. In the present work, we investigated the ecological impact of six formulations, which represent the "new generation" organic UV filters such as diethylamino hydroxybenzoyl hexyl benzoate (DHHB), methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT), ethylhexyl triazone (EHT), and bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT), which are progressively replacing the "old generation" organic UV filters (e.g., oxybenzone, octinoxate) banned in several countries of the world. The six formulations tested were characterized by a different combination of ingredients, on a model species particularly sensitive to environmental alterations: the sea urchin, Paracentrotus lividus. We investigated the sea urchin responses both in terms of gene expression and anomalies in embryonic development. We found that all sunscreen products containing only MBBT, DHHB, BEMT, and EHT as UV filters, are more eco-compatible than those also containing also ES, or other ingredients such as emollients and texturizing compounds, which may act synergistically causing molecular stress, morphological anomalies, and ultimately possible death. Overall, the results presented here provide new insights on the effects of sunscreen products based on "new generation" UV filters, and highlights the urgency of testing complete formulations, rather than just specific UV filters to ascertain the eco-compatibility of sunscreen products, to effectively minimize their impact on marine ecosystems.

Environmental impacts due to the use of sunscreen products: a mini-review

Sunscreen use has increased in recent years, as sunscreen products minimize the damaging effects of solar radiation. Active ingredients called ultraviolet (UV) filters or UV agents, either organic or inorganic, responsible for defending skin tissue against harmful UV rays, are incorporated in sunscreen formulations. UV agents have a serious impact on many members of bio communities, and they are transferred to the environment either directly or indirectly. Many organic UV filters are found to be accumulated in marine environments because of high values of the octanol/water partition coefficient. However, due to the fact that UV agents are not stable in water, unwanted by-products may be formed. Experimental studies or field observations have shown that organic UV filters tend to bioaccumulate in various aquatic animals, such as corals, algae, arthropods, mollusks, echinoderms, marine vertebrates. This review was conducted in order to understand the effects of UV agents on both the environment and marine biota. In vivo and in vitro studies of UV filters show a wide range of adverse effects on the environment and exposed organisms. Coral bleaching receives considerable attention, but the scientific data identify potential toxicities of endocrine, neurologic, neoplastic and developmental pathways. However, more controlled environmental studies and long-term human use data are limited. Several jurisdictions have prohibited specific UV filters, but this does not adequately address the dichotomy of the benefits of photoprotection vs lack of eco-friendly, safe, and approved alternatives.

Evaluation of fluorescence-based viability stains in cells dissociated from scleractinian coral Pocillopora damicornis

The application of established cell viability assays such as the commonly used trypan blue staining method to coral cells is not straightforward due to different culture parameters and different cellular features specific to mammalian cells compared to marine invertebrates. Using Pocillopora damicornis as a model, we characterized the autofluorescence and tested different fluorescent dye pair combinations to identify alternative viability indicators. The cytotoxicity of different representative molecules, namely small organic molecules, proteins and nanoparticles (NP), was measured after 24 h of exposure using the fluorescent dye pair Hoechst 33342 and SYTOX orange. Our results show that this dye pair can be distinctly measured in the presence of fluorescent proteins plus chlorophyll. P. damicornis cells exposed for 24 h to Triton-X100, insulin or titanium dioxide (TiO₂) NPs, respectively, at concentrations ranging from 0.5 to 100 µg/mL, revealed a LC50 of 0.46 µg/mL for Triton-X100, 6.21 µg/mL for TiO₂ NPs and 33.9 µg/mL for insulin. This work presents the approach used to customize dye pairs for membrane integrity-based cell viability assays considering the species- and genotype-specific autofluorescence of scleractinian corals, namely: endogenous fluorescence characterization followed by the selection of dyes that do not overlap with endogenous signals.

Survey on endocrine-disrupting chemicals in seafood: Occurrence and distribution

Currently, the presence of endocrine disrupting chemicals (EDCs) in the marine environment pose а potential risk to both wildlife and human health. The occurrence of EDCs in seafood depends of several factors such as source and amounts of EDCs that reach the aquatic environment, physicochemical features of EDCs, and its accumulation in trophic chain. This review highlights the occurrence and distribution of EDCs along the seafood in the last 6 years. The following EDCs were included in this review: brominated flame retardants (PBDEs, PBBs, HBCDDs, TBBPA, and novel flame retardants); pharmaceuticals (paracetamol, ibuprofen, diclofenac, carbamazepine), bisphenols, hormones, personal care products (Musk and UV Filters), and pesticides (organochlorides, organophosphates, and pyrethroids). Some of them were found above the threshold that may cause negative effects on human, animal, and environmental health. More control in some countries, as well as new legislation and inspection over the purchase, sale, use, and production of these compounds, are urgently needed. This review provides data to support risk assessment and raises critical gaps to stimulate and improve future research.

Temporal variability in TiO2 engineered particle concentrations in rural Edisto River

Titanium dioxide (TiO₂) is widely used in engineered particles including engineered nanomaterial (ENM) and pigments, yet its occurrence, concentrations, temporal variability, and fate in natural environmental systems are poorly understood. For three years, we monitored TiO₂ concentrations in a rural river basin (Edisto River, < 1% urban land cover) in South Carolina, United States. The total concentrations of Ti, Nb, Al, Fe, Ce, and La in the Edisto River trended higher during spring/summer compared to autumn/winter. Upward trending Ti/Nb ratio in the spring/summer compared to near-background autumn/winter ratios of 255.7 ± 8.9 indicated agricultural preparation and growing-season-related increases in TiO₂ engineered particles. In contrast, downward trending of the Ti/Al and Ti/Fe ratios in the spring and summer compared to the near-background autumn/winter ratios of 0.05 indicated greater mobilization of Fe and Al, relative to Ti during spring/summer. Surface-water concentrations of TiO₂ engineered particles varied between 0 and 128.7 ± 3.9 μg TiO₂ L^-1. Increases in TiO₂ concentrations over the spring/summer were associated with increases in phosphorus, orthophosphate, nitrate, ammonia, anthropogenic gadolinium, water temperature, suspended sediments, organic carbon, and alkalinity, and with decreases in dissolved oxygen. The association between these contaminants together with the timing of the increases in their concentrations is consistent with diffuse wastewater sources, such as reuse application overspray, biosolids fertilization, leaking sewers, or septic tanks, as the driver of instream concentrations; however, other diffuse sources cannot be ruled out. The findings of this study indicate spatially-distributed (non-point source) releases can result in high concentrations of TiO₂ engineered particles, which may pose higher risks to rural stream aquatic ecosystems during the agricultural season. The results illustrate the importance of monitoring seasonal variations in engineered particles concentrations in surface waters for a more representative assessment of ecosystem risk.

UV filters and their impact on marine life: state of the science, data gaps, and next steps

Sunscreens containing broad-spectrum ultraviolet (UV) filters play an essential role in protecting the skin against the damage induced by sun overexposure. However, the widespread use of sunscreens and other personal care products containing these filters has led to these compounds being widely detected in the environment and being identified as emerging pollutants in marine waters. Concerns raised by laboratory studies investigating the potential impact of UV filters on coral communities have already led to bans on the use of some sunscreens in a few tourist hotspots. Although UV filter pollution may be just one of the many environmental factors impacting coral health worldwide, the media attention surrounding these studies and the legislative changes may lead patients to question dermatologists about the environmental safety of some sunscreen products. This review provides an overview of current knowledge on the impact of UV filters on marine ecosystems, concentrating on recent studies examining the effects of commonly used filters on organisms at low trophic levels and of how alternative approaches, such as metabolomics, can be used to further assess UV filter ecotoxicity. Current gaps in our knowledge are also discussed, most notably the need to increase our understanding of the longer-term fate and behaviour of UV filters in the marine environment, develop more adapted standardized ecotoxicity tests for a wider range of marine species, and evaluate the impact of UV filters on the marine food web. We then discuss future perspectives for the development of new, more environmentally friendly, filters that may enable the use of the most toxic compounds to be reduced without compromising the effectiveness of sunscreen formulations. Finally, we consider how dermatologists play a key role in educating patients on the need for a balanced approach to sun exposure, sun protection, and conservation of the marine environment.

Towards the Development of Standardized Bioassays for Corals: Acute Toxicity of the UV Filter Benzophenone-3 to Scleractinian Coral Larvae

Coral reefs have been declining globally at a historically unprecedented rate. Ultraviolet (UV) filters used in sunscreens may contribute to this decline at local scales, which has already led to bans on various organic UV filters in some regions. However, the underlying studies for these bans demonstrated significant flaws in the experimental design due to a lack of validated and standardized testing methods for corals. This study aimed to investigate options for the development of a standard acute toxicity test for the larval stage of scleractinian corals. Planula larvae of two brooding (Leptastrea purpurea and Tubastraea faulkneri) and two spawning (Acropora digitifera and A. millepora) species were exposed to the organic UV filter benzophenone-3 (BP3) for 48 h under static conditions. We observed interspecific variations in toxicity, with A. digitifera being the most sensitive (LC₅₀ = 0.75 µg L⁻¹) and T. faulkneri the least sensitive (LC₅₀ = 2951.24 µg L⁻¹) species. Inhibition of settlement was found to be a useful endpoint leading to an EC₅₀ of 1.84 µg L⁻¹ in L. purpurea larvae. Although the analytical challenges of measuring lipophilic substances in small volume test setups remain, the here applied test design and selected endpoints are suitable for further validation and subsequent standardization.

Mediterranean seagrass Posidonia oceanica accumulates sunscreen UV filters

Certain ultra-violet filter (UVF) components of solar creams have negative impacts on coral reefs and have been prohibited in international tourism destinations (i.e., Hawaii, Florida, and Palau) to protect coral reefs. In the Mediterranean coasts which are also hotspots of international tourism and where endemic seagrass Posidonia oceanica forms extensive meadows, the accumulation of UVF components have not been studied. We report for the first time, that the rhizomes of P. oceanica internally accumulated UVFs BP3, BP4, AVO, 4MBC and MeBZT and the paraben preservative MePB. The components BP4 and MePB occurred in higher concentrations reaching up to 129 ng g^-1 dw and 512 ng g^-1 dw, respectively. This work emphasizes the need for more experimental studies on the effects of UVFs on seagrasses and check if we should follow suit to prohibit certain UVFs to protect this species as what has been done in other regions to protect corals.

UV Filters: Challenges and Prospects

The use of sunscreens is an established and recommended practice to protect skin from solar-induced damage. Around 30 UV filters can be used in sunscreen products in the European Union, which ought to follow the requirements of the regulation 1223/2009 to ensure their efficacy and safety for humans. Nevertheless, low photostability and putative toxicity for humans and environment have been reported for some UV filters. Particularly, the negative impact in marine organisms has recently raised concern on the scientific community. Therefore, it is important to develop new UV filters with improved safety profile and photostability. Over the last two decades, nearly 200 new compounds have revealed promising photoprotection properties. The explored compounds were obtained through different approaches, including exploration of natural sources, synthetic pathways, and nanotechnology. Almost 50 natural products and around 140 synthetic derivatives, such as benzimidazoles, benzotriazoles, hydroxycinnamic acids, xanthones, triazines, among others, have been studied aiming the discovery of novel, effective, and safer future photoprotective agents. Herein, we provide the reader with an overview about UV filters’ challenges and prospects, offering a forward-looking to the next-generation of UV filters.

Environmental Fate and Toxicity of Sunscreen-Derived Inorganic Ultraviolet Filters in Aquatic Environments: A Review

An increasing number of inorganic ultraviolet filters (UVFs), such as nanosized zinc oxide (nZnO) and titanium dioxide (nTiO2), are formulated in sunscreens because of their broad UV spectrum sunlight protection and because they limit skin damage. However, sunscreen-derived inorganic UVFs are considered to be emerging contaminants; in particular, nZnO and nTiO2 UVFs have been shown to undergo absorption and bioaccumulation, release metal ions, and generate reactive oxygen species, which cause negative effects on aquatic organisms. We comprehensively reviewed the current study status of the environmental sources, occurrences, behaviors, and impacts of sunscreen-derived inorganic UVFs in aquatic environments. We find that the associated primary nanoparticle characteristics and coating materials significantly affect the environmental behavior and fate of inorganic UVFs. The consequential ecotoxicological risks and underlying mechanisms are discussed at the individual and trophic transfer levels. Due to their persistence and bioaccumulation, more attention and efforts should be redirected to investigating the sources, fate, and trophic transfer of inorganic UVFs in ecosystems.

Biomarker-based assessment of sublethal toxicity of organic UV filters (ensulizole and octocrylene) in a sentinel marine bivalve Mytilus edulis

The global occurrence of organic UV filters in the marine environment is of increasing ecotoxicological concern. Here we assessed the toxicity of UV filters ensulizole and octocrylene in the blue mussels Mytilus edulis exposed to 10 or 100 μg l^-1 of octocrylene and ensulizole for two weeks. An integrated battery of biochemical and molecular biomarkers related to xenobiotics metabolism and cellular toxicity (including oxidative stress, DNA damage, apoptosis, autophagy and inflammation) was used to assess the toxicity of these UV filters in the mussels. Octocrylene (but not ensulizole) accumulated in the mussel tissues during the waterborne exposures. Both studied UV filters induced sublethal toxic effects in M. edulis at the investigated concentrations. These effects involved induction of oxidative stress, genotoxicity (indicated by upregulation of DNA damage sensing and repair markers), upregulation of apoptosis and inflammation, and dysregulation of the xenobiotic biotransformation system. Octocrylene induced cellular stress in a concentration-dependent manner, whereas ensulizole appeared to be more toxic at the lower (10 μg l^-1) studied concentration than at 100 μg l^-1. The different concentration-dependence of sublethal effects and distinct toxicological profiles of ensulizole and octocrylene show that the environmental toxicity is not directly related to lipophilicity and bioaccumulation potential of these UV filters and demonstrate the importance of using bioassays for toxicity assessment of emerging pollutants in coastal marine ecosystems.

Hyaluronic acid/tannic acid hydrogel sunscreen with excellent anti-UV, antioxidant, and cooling effects

Excessive exposure to UV radiation is one of the major factors that causes skin aging, erythema, burns, and skin cancer. Recently, the usage of sunscreens for skin protection has increased because the amount of UV radiation reaching the Earth's surface has increased owing to the destruction of the ozone layer that blocks UV radiation. Hydrogels with a three-dimensional network structure exhibit physical and chemical properties that are similar to those of the extracellular matrix in the human body, a high water content, flexibility, and biocompatibility. Therefore, they are applied in a wide range of fields, such as in cosmetics, medicines, and pharmaceuticals. However, conventional hydrogel-based sunscreens have drawbacks such as complicated process conditions, high cost, and low biocompatibility. In this study, a novel hydrogel-type sunscreen with excellent UV protection and cooling effects was prepared by a very simple process using two natural materials, hyaluronic acid (HA) and tannic acid (TA). The HA/TA hydrogels exhibited broad-spectrum UV protection in the UVA and UVB regions (280-360 nm). In addition, they showed excellent adhesion to the skin surface, antioxidative activity, cooling effect, and high moisture content, demonstrating great application potential as a hydrogel-type sunscreen.

UV-filter pollution: current concerns and future prospects

UV-filters are widely used in cosmetics and personal care products to protect users' skin from redamage caused by ultraviolet (UV) radiation from the sun. Globally, an estimated 16,000 to 25,000 tonnes of products containing UV-filters were used in 2014 with modern consumption likely to be much higher. Beyond this use in cosmetics and personal care products, UV-filters are also widely used to provide UV-stability in industrial products such as paints and plastics. This review discusses the main routes by which UV-filters enter aquatic environments and summarises the conclusions of studies from the past 10 years that have investigated the effects of UV-filters on environmentally relevant species including corals, microalgae, fish, and marine mammals. Safety data regarding the potential impact of UV-filters on human health are also discussed. Finally, we explore the challenges surrounding UV-filter removal and research on more environmentally friendly alternatives to current UV-filters.

Acute toxicity of the UV filter oxybenzone to the coral Galaxea fascicularis

Coral reefs are impacted by a variety of anthropogenic stressors including inputs of chemical contaminants. Although data is currently limited, sunscreens containing ultraviolet (UV) filters have recently been suggested as an emerging class of chemical contaminants. To provide further data on the toxicity of the UV filter oxybenzone (benzophenone-3 or BP-3) to corals, we conducted three independent acute toxicity tests exposing the colonial stony coral Galaxea fascicularis to BP-3 (0.31 to 10 mg/L nominal concentrations). Assessments included daily analytical verification of the exposure concentrations, calculation of the lethal concentration to result in 50% mortality (LC50) and numerous biological endpoints to further investigate the potential impact to both the coral and symbiont. LC50s for the three tests were similar and averaged 6.53 ± 0.47 mg/L nominal concentration BP-3 (4.45 mg/L measured dissolved BP-3). BP-3 did not initiate coral bleaching or show a significant loss of symbionts from the coral tissue in this species as reductions in measurements used for bleaching (i.e. visual color, color saturation and photosynthetic pigment concentrations) were only seen concurrently with tissue loss (i.e. at ≥2.5 mg/L nominal concentration BP-3). Polyp retraction, the most sensitive endpoint of this test, was seen to be a sub-lethal behavioral response to BP-3 exposure. Using the calculated LC50 with measured concentrations from a high-quality UV filter monitoring study in Hawaii, a preliminary, conservative risk quotient for BP-3 was calculated at 0.032. These results suggest that BP-3 likely does not pose an acute risk of mortality to G. fascicularis and additional testing is required to determine sublethal impacts of BP-3 under environmentally relevant concentrations and longer-term chronic exposures. This study highlights complications in conducting toxicity tests with organic UV filters including under-estimations of exposure concentrations and provides recommendations to improve these methods for better comparisons between studies.

UV filters used in sunscreens-A lack in current coral protection?

Ultraviolet (UV) filters used in sunscreens are among the anthropogenic substances that may enter the marine environment by both indirect (via wastewater) and direct pathways (leisure activities). Owing to the recent global decline in coral population, the impact of those UV filters on the coral health is currently under increased investigation. First results from scientists suggest that some of the filters may be toxic to various coral life stages, but an initial cross comparison with existing data from other freshwater organisms does not indicate that corals are specifically more susceptible to UV filters than other standard species. In fact, the available data leading to this conclusion is still vague and based on toxicity and bioaccumulation tests with corals, which are both still at the research stage. To facilitate a proper hazard assessment, robust experimental procedures for coral ecotoxicological studies are considered mandatory. In other words, additional steps should be taken to standardize and validate such new test systems to generate reliable results, which then can be used in regulatory decision making. Furthermore, to facilitate a more detailed and site-specific environmental risk assessment in the marine area, an application-based exposure scenario must be developed. Until these data and tools become available, environmental hazard and risk assessments may be carried out using existing data from freshwater organisms and existing tonnage-based exposure scenarios as a potential surrogate. Integr Environ Assess Manag 2021;17:926-939. © 2021 SETAC.

Sunscreens’ UV Filters Risk for Coastal Marine Environment Biodiversity: A Review

Considering the rapid growth of tourism in recent years and the acknowledgement that exposure to solar UV radiation may cause skin cancer, sunscreens have been widely used by beachgoers in recent decades. UV filters contained in sunscreens, however, were recently identified as emerging pollutants in coastal waters since they accumulate in the marine environment with different adverse effects. In fact, exposure to these components was proven to be toxic to most invertebrate and vertebrate marine species. Some UV filters are linked to the production of significant amounts of reactive oxygen species (ROS), such as hydrogen peroxide, and the release of inorganic micronutrients that may alter the status of coastal habitats. Bioaccumulation and biomagnification have not yet been fully addressed. This review highlights recent progress in research and provides a comprehensive overview of the toxicological and ecotoxicological effects of the most used UV filters both on the abiotic and biotic compartments in different types of coastal areas, to gain a better understanding of the impacts on coastal biodiversity.

Eco-friendly sunscreen formulation based on starches and PEG-75 lanolin increases the antioxidant capacity and the light scattering activity in the visible light

Most modern sunscreens contain physical filters, which scatter the sunlight, increasing the photons' pathway in the upper stratum corneum. This effect can lead to a better efficacy of the UV filters and improve the diffuse reflection. However, the addition of nanosized inorganic UV filters reduces the antioxidant capacity of sunscreen formulations. Two cream formulations (F1, F2) which differ in the ingredient PEG75 Lanolin (F2), have been characterized for their radical protection factor (RPF) and their optical properties in vitro using electron paramagnetic resonance (EPR) spectroscopy and UV/VIS spectrometry. The RPF for PEG-75 Lanolin was also determined. Furthermore, their radical protection properties were analyzed on porcine skin ex vivo after visible light irradiation by EPR. The structure of each formulation in the skin surface was determined by reflectance confocal microscopy in vivo. The addition of lanolin increased the reflectance and reduced the transmittance for visible light, improving the scattering drastically. Besides, the antioxidant capacity was also increased for F2, something unpublished until now. F1 presented a lower scattering provided by starches. The sunscreens showed high scattering properties and antioxidant capacity, especially for F2, which presented the lowest radical formation in the skin model. These results are consistent with the RPF measurements where F2 has a higher RPF value (193 ± 3 × 10¹⁴ radicals/mg) than F1 (155 ± 4 × 10¹⁴ radicals/mg) and for PEG-75 Lanolin (37 ± 1 × 10¹⁴ radicals/mg). The combination of starches and PEG-75 Lanolin is the first solution to provide both, light scattering and antioxidant capacity, in sunscreens.

From Sea to Skin: Is There a Future for Natural Photoprotectants?

In the last few decades, the thinning of the ozone layer due to increased atmospheric pollution has exacerbated the negative effects of excessive exposure to solar ultraviolet radiation (UVR), and skin cancer has become a major public health concern. In order to prevent skin damage, public health advice mainly focuses on the use of sunscreens, along with wearing protective clothing and avoiding sun exposure during peak hours. Sunscreens present on the market are topical formulations that contain a number of different synthetic, organic, and inorganic UVR filters with different absorbance profiles, which, when combined, provide broad UVR spectrum protection. However, increased evidence suggests that some of these compounds cause subtle damage to marine ecosystems. One alternative may be the use of natural products that are produced in a wide range of marine species and are mainly thought to act as a defense against UVR-mediated damage. However, their potential for human photoprotection is largely under-investigated. In this review, attention has been placed on the molecular strategies adopted by marine organisms to counteract UVR-induced negative effects and we provide a broad portrayal of the recent literature concerning marine-derived natural products having potential as natural sunscreens/photoprotectants for human skin. Their chemical structure, UVR absorption properties, and their pleiotropic role as bioactive molecules are discussed. Most studies strongly suggest that these natural products could be promising for use in biocompatible sunscreens and may represent an alternative eco-friendly approach to protect humans against UV-induced skin damage.

The biological activity of the organic UV filter ethylhexyl methoxycinnamate in rainbow trout (Oncorhynchus mykiss)

UV filters are able to enter the aquatic environment and negatively affect non-target organisms. The aim of this study was to evaluate subchronic exposure to ethylhexyl methoxycinnamate (EHMC) in rainbow trout. The tested EHMC concentrations of 6.9 (low), 96.0 (medium) and 395.6 μg/kg (high) were used. The lowest concentration was based on environmentally relevant concentrations. The higher concentrations were chosen as a multiple of the lowest one to determine the dose-response relationship. EHMC was incorporated into feed pellets. The experiment was conducted for six weeks in a semi-static system. Haematological, biochemical and oxidative stress indices were determined at the end of the experiment and supplemented by histological examination. Significant changes were proven at medium and high concentrations of EHMC. Specifically, increases of glucose, lactate and decrease of albumin and total protein in plasma indicate a stress ethology. Moreover, a decrease of plasma cholesterol, triacylglycerols and ammonia were observed even in the experimental group exposed to the lowest concentration of EHMC, perceived as an environmentally relevant concentration. The ferric reducing ability of plasma was decreased in all tested concentrations. Exposure to the highest concentration of EHMC resulted in a decrease in leukocyte counts. Increased activity of glutathione peroxidase in liver was recorded for the medium and the highest concentration of EHMC. The level of the thiobarbituric acid reactive substances in kidney was elevated for the highest concentration. Decrease of the activity of glutathione-S-transferase in gills for medium concentration of EHMC was registered. Histopathological examination revealed massive destruction of hepatic parenchyma at the highest concentration of EHMC. All these results support the finding of a stress load on the fish organism. In summary, although subchronic exposure to EHMC had no effect on behaviour, mortality or feed intake, this exposure resulted in the alteration of saccharide, lipid and protein metabolism and weakened antioxidant capacity.

Potentiation of lethal and sub-lethal effects of benzophenone and oxybenzone by UV light in zebrafish embryos

Benzophenones are widely used as organic UV filters in many personal care products, especially sunscreen, to protect humans from UV radiation. The increasing use of benzophenone class UV filters has raised concerns about the potential effects on the aquatic environment. These organic UV filters are designed to absorb UV light. However, to date, studies have not considered the potential of UV light to potentiate the toxicity of benzophenones in aquatic organisms. In this study using zebrafish embryos, we assessed the median lethal concentration (LC₅₀) and sub-lethal effects of benzophenone and oxybenzone either under natural levels of UV light or under laboratory light conditions. The LC₅₀ value in zebrafish embryos under both light conditions of oxybenzone was lower when compared to benzophenone. Interestingly, UV light significantly decreased the LC₅₀ values (increased toxicity) of both benzophenone and oxybenzone. The presence of UV light induced a significant increase in hydroxyl radical formation and this was reflected in both increased SOD activity and lipid peroxidation in oxybenzone treated groups. Exposure to either benzophenone or oxybenzone also delayed hatching between 60 and 96 hpf when comparing to the control group while UV exposure further delayed hatching only in oxybenzone-exposed embryos. The results demonstrate the importance of involving UV light in toxicity testing for UV filters and provide much-need information on the UV-induced toxicity of benzophenone and oxybenzone under ecologically realistic conditions.

Stem cells of aquatic invertebrates as an advanced tool for assessing ecotoxicological impacts

Environmental stressors are assessed through methods that quantify their impacts on a wide range of metrics including species density, growth rates, reproduction, behaviour and physiology, as on host-pathogen interactions and immunocompetence. Environmental stress may induce additional sublethal effects, like mutations and epigenetic signatures affecting offspring via germline mediated transgenerational inheritance, shaping phenotypic plasticity, increasing disease susceptibility, tissue pathologies, changes in social behaviour and biological invasions. The growing diversity of pollutants released into aquatic environments requires the development of a reliable, standardised and 3R (replacement, reduction and refinement of animals in research) compliant in vitro toolbox. The tools have to be in line with REACH regulation 1907/2006/EC, aiming to improve strategies for potential ecotoxicological risks assessment and monitoring of chemicals threatening human health and aquatic environments. Aquatic invertebrates' adult stem cells (ASCs) are numerous and can be pluripotent, as illustrated by high regeneration ability documented in many of these taxa. This is of further importance as in many aquatic invertebrate taxa, ASCs are able to differentiate into germ cells. Here we propose that ASCs from key aquatic invertebrates may be harnessed for applicable and standardised new tests in ecotoxicology. As part of this approach, a battery of modern techniques and endpoints are proposed to be tested for their ability to correctly identify environmental stresses posed by emerging contaminants in aquatic environments. Consequently, we briefly describe the current status of the available toxicity testing and biota-based monitoring strategies in aquatic environmental ecotoxicology and highlight some of the associated open issues such as replicability, consistency and reliability in the outcomes, for understanding and assessing the impacts of various chemicals on organisms and on the entire aquatic environment. Following this, we describe the benefits of aquatic invertebrate ASC-based tools for better addressing ecotoxicological questions, along with the current obstacles and possible overhaul approaches.

Finding Nano: Challenges Involved in Monitoring the Presence and Fate of Engineered Titanium Dioxide Nanoparticles in Aquatic Environments

In recent years, titanium dioxide (TiO2) has increasingly been used as an inorganic ultraviolet (UV) filter for sun protection. However, nano-TiO2 may also pose risks to the health of humans and the environment. Thus, to adequately assess its potential adverse effects, a comprehensive understanding of the behaviour and fate of TiO2 in different environments is crucial. Advances in analytical and modelling methods continue to improve researchers’ ability to quantify and determine the state of nano-TiO2 in various environments. However, due to the complexity of environmental and nanoparticle factors and their interplay, this remains a challenging and poorly resolved feat. This paper aims to provide a focused summary of key particle and environmental characteristics that influence the behaviour and fate of sunscreen-derived TiO2 in swimming pool water and natural aquatic environments and to review the current state-of-the-art of single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) approaches to detect and characterise TiO2 nanoparticles in aqueous media. Furthermore, it critically analyses the capability of existing fate and transport models to predict environmental TiO2 levels. Four particle and environmental key factors that govern the fate and behaviour of TiO2 in aqueous environments are identified. A comparison of SP-ICP-MS studies reveals that it remains challenging to detect and characterise engineered TiO2 nanoparticles in various matrices and highlights the need for the development of new SP-ICP-MS pre-treatment and analysis approaches. This review shows that modelling studies are an essential addition to experimental studies, but they still lack in spatial and temporal resolution and mostly exclude surface transformation processes. Finally, this study identifies the use of Bayesian Network-based models as an underexplored but promising modelling tool to overcome data uncertainties and incorporates interconnected variables.

Biomaterials for Three-Dimensional Cell Culture: From Applications in Oncology to Nanotechnology

Three-dimensional cell culture has revolutionized cellular biology research and opened the door to novel discoveries in terms of cellular behavior and response to microenvironment stimuli. Different types of 3D culture exist today, including hydrogel scaffold-based models, which possess a complex structure mimicking the extracellular matrix. These hydrogels can be made of polymers (natural or synthetic) or low-molecular weight gelators that, via the supramolecular assembly of molecules, allow the production of a reproducible hydrogel with tunable mechanical properties. When cancer cells are grown in this type of hydrogel, they develop into multicellular tumor spheroids (MCTS). Three-dimensional (3D) cancer culture combined with a complex microenvironment that consists of a platform to study tumor development and also to assess the toxicity of physico-chemical entities such as ions, molecules or particles. With the emergence of nanoparticles of different origins and natures, implementing a reproducible in vitro model that consists of a bio-indicator for nano-toxicity assays is inevitable. However, the maneuver process of such a bio-indicator requires the implementation of a repeatable system that undergoes an exhaustive follow-up. Hence, the biggest challenge in this matter is the reproducibility of the MCTS and the associated full-scale characterization of this system's components.

Nano-Structured Lignin as Green Antioxidant and UV Shielding Ingredient for Sunscreen Applications

Green, biocompatible, and biodegradable antioxidants represent a milestone in cosmetic and cosmeceutical applications. Lignin is the most abundant polyphenol in nature, recovered as a low-cost waste from the pulp and paper industry and biorefinery. This polymer is characterized by beneficial physical and chemical properties which are improved at the nanoscale level due to the emergence of antioxidant and UV shielding activities. Here we review the use of lignin nanoparticles in cosmetic and cosmeceutical applications, focusing on sunscreen and antiaging formulations. Advances in the technology for the preparation of lignin nanoparticles are described highlighting structure activity relationships.

Sunscreens: UV filters to protect us: Part 2-Increasing awareness of UV filters and their potential toxicities to us and our environment

BACKGROUND

Sunscreens are topical preparations containing one or more compounds that filter, block, reflect, scatter, or absorb ultraviolet (UV) light. Part 2 of this review focuses on the environmental, ecological effects and human toxicities that have been attributed to UV filters.

METHODS

Literature review using NIH databases (eg, PubMed and Medline), FDA and EPA databases, Google Scholar, the Federal Register, and the Code of Federal Regulations (CFR).

LIMITATIONS

This was a retrospective literature review that involved many different types of studies across a variety of species. Comparison between reports is limited by variations in methodology and criteria for toxicity.

CONCLUSIONS

In vivo and in vitro studies on the environmental and biological effects of UV filters show a wide array of unanticipated adverse effects on the environment and exposed organisms. Coral bleaching receives considerable attention from the lay press, but the scientific literature identifies potential toxicities of endocrine, neurologic, neoplastic and developmental pathways. These effects harm a vast array of aquatic and marine biota, while almost no data supports human toxicity at currently used quantities (with the exception of contact allergy). Much of these data are from experimental studies or field observations; more controlled environmental studies and long-term human use data are limited. Several jurisdictions have prohibited specific UV filters, but this does not adequately address the dichotomy of the benefits of photoprotection vs lack of eco-friendly, safe, and FDA-approved alternatives.