Effects of TiO2 nanoparticles and sunscreens on coastal marine microalgae: Ultraviolet radiation is key variable for toxicity assessment

Responses of different species of marine microalgae and their community to gear-derived microplastics

The impact of gear-derived microplastics (MPs) on microalgal community stability is unknown. In this work, three types of gear-derived MPs were obtained from floats, pallets, and tires. After exposure to individual microalgal species (Phaeodactylum tricornutum, Chaetoceros curvisetus, Chlorella vulgaris, Isochrysis galbana), small-sized MPs (22 μm) exhibited stronger toxicity than large-sized MPs (135 μm), and the toxicity was MPs concentration independent. The three MPs (1 mg/L) significantly inhibited the growth of P. trichodinium, C. curvisetus and I. galbana. P. tricornutum was the most sensitive species, and the MPs decreased its chl a content, increased ROS level and reduced membrane integrity. Strong heteroaggregation with MPs is a cause of the observed toxicity. Furthermore, algal community was constructed using these four algal species, and P. tricornutum became the dominant species after community stability. After 96-h exposure to small-sized MPs at all the tested concentrations, the proportion of P. tricornutum highly decreased, thus increasing community stability and diversity maintenance. Photo-aging (20 days) further decreased algal number in the community from 16.54 % (original MPs) to 25.12 % (photo-aged MPs), while the Shannon diversity index increased from 0.93 to 0.99. The introduction of harmful algae (Alexandrium tamarense) decreased total algal number in algal community by 45.10 %, and led to the replacement of dominant species to C. vulgaris. Interestingly, algal number after the exposure of MPs and aged MPs recovered by 7.59 % and 14.71 %, respectively. This work provides useful information on the risk of gear-derived MPs to microalgal community in marine environments (especially mariculture areas).

Transcriptomic and physiological analyses reveal the toxic effects of inorganic filters (nZnO and nTiO2) on scleractinian coral Galaxea fascicularis

The effects of sunscreen on scleractinian corals have garnered widespread attention; however, the toxic effects and mechanisms remain unclear. This study investigated the toxicological effects of two common inorganic filters used in sunscreens, nano zinc oxide and titanium dioxide (nZnO and nTiO₂), on the reef-building coral Galaxea fascicularis, focusing on the phenotypic, physiological, and transcriptomic responses. The results showed that after exposure to 0.8 mg/L of nZnO and 30 mg/L of nTiO₂ for 48 h, all coral polyps exhibited retraction. Zn and Ti ions were detected in coral tissues at concentrations of 67.18 and 24.87 μg/g, respectively, indicating the accumulation of nZnO and nTiO2 in coral tissues. The zooxanthellae density, Fv/Fm, and chlorophyll-a content decreased significantly. The activity of antioxidant enzymes showed an increasing trend. Meanwhile, glutamine synthetase and glutamate dehydrogenase activities exhibited a decreasing trend. The health status of corals was impacted as a result of nZnO and nTiO2 stress. Transcriptomic analysis showed that the toxicity mechanisms of nZnO and nTiO2 differed in corals. Following exposure to nZnO, differentially expressed genes (DEGs) in corals were mainly enriched in signaling pathways related to immune response. The genes related to innate immunity, such as MASP1, MUC5AC, TLRs, and C2, were significantly upregulated, indicating that nZnO exposure induces an innate immune response in corals. Meanwhile, following nTiO2 exposure, the upregulated DEGs were mainly enriched in signaling pathways related to transporter activity. In contrast, the downregulated DEGs were mainly enriched in energy metabolism pathways, indicating that nTiO2 disrupted the energy supply of corals, thereby leading to an increased demand for nutrient transport. This study reveals the toxic effects of nZnO and nTiO2, and their mechanisms of action on scleractinian corals, providing a reference for further assessing the toxicity of sunscreen on corals.

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.

Cosmetic Products with Potential Photoprotective Effects Based on Natural Compounds Extracted from Waste of the Winemaking Industry

Grape marc is a by-product resulting from the winemaking industry that still contains beneficial compounds that can be valorized. Thus, we report here the possibility of using polyphenolic extracts of grape marc origin to obtain sun protection creams. The extractions were performed in ethanol and acetone solutions using pomace from different grape varieties (Merlot, Bläufrankisch, Fetească Neagră, Isabella) as a raw material. The obtained extracts were analyzed in order to determine the total phenolic content, the antioxidant activity, and the sun protection factor (SPF) via Mansur spectrophotometric assay. The best results were achieved using 70% ethanol in water as a solvent. The extracts with the highest potential photoprotective effects are from the Merlot variety (SPFspectrophotometric = 7.83 ± 0.76). The sunscreens were prepared using the 70% ethanolic extract of the Merlot variety evaporated to dryness, redissolved in either distilled water or ethanol. The SPF estimated in vitro via the COLIPA method showed values of 14.07 ± 1.50 and 11.46 ± 1.32 for the aqueous and ethanolic extracts, respectively, when working with a cream to polyphenolic extract a ratio of 1/1 (w/w). At the same time, the use of aqueous polyphenolic extracts ensures the better stability of creams compared with the ethanolic ones.

Biocompounds from wastewater-grown microalgae: a review of emerging cultivation and harvesting technologies

Microalgae biomass has attracted attention as a feedstock to produce biofuels, biofertilizers, and pigments. However, the high production cost associated with cultivation and separation stages is a challenge for the microalgae biotechnology application on a large scale. A promising approach to overcome the technical-economic limitations of microalgae production is using wastewater as a nutrient and water source for cultivation. This strategy reduces cultivation costs and contributes to valorizing sanitation resources. Therefore, this article presents a comprehensive literature review on the status of microalgae biomass cultivation in wastewater, focusing on production strategies and the accumulation of valuable compounds such as lipids, carbohydrates, proteins, fatty acids, and pigments. This review also covers emerging techniques for harvesting microalgae biomass cultivated in wastewater, discussing the advantages and limitations of the process, as well as pointing out the main research opportunities. The novelty of the study lies in providing a detailed analysis of state-of-the-art and potential advances in the cultivation and harvesting of microalgae, with a special focus on the use of wastewater and implementing innovative strategies to enhance productivity and the accumulation of compounds. In this context, the work aims to guide future research concerning emerging technologies in the field, emphasizing the importance of innovative approaches in cultivating and harvesting microalgae for advancing knowledge and practical applications in this area.

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.

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.

Nanomaterials in sunscreens: Potential human and ecological health implications

Inorganic nanomaterials such as TiO2 and ZnO provide significant benefits in terms of UV protection, and their use generally has increased in commercial sunscreens. However, more recently there have been concerns about their potential human and ecological health implications, mostly driven by perception rather than by formal assessments. The large and increasing body of literature on these nanomaterials indicates that in most circumstances their risk are minimal. Penetration of the human epidermis is minimal for these nanomaterials, significantly reducing the potential effects that these nanomaterials may pose to internal organs. The excess Zn ion dose is very small compared to normal dietary consumption of Zn, which is a necessary element. The levels of residual nanomaterials or released ions in public swimming pools is also low, with minimal effect in case this water is ingested during swimming or bathing. In natural environments with significant water flow due to wind and water currents, the concentrations of nanomaterials and released ions are generally well below levels that would cause effects in aquatic organisms. However, sensitive habitats with slow currents, such as coral reefs, may accumulate these nanomaterials. The number of studies of the levels and effects of nanomaterials in these sensitive habitats is very small; more research is needed to determine if there is an elevated risk to these ecosystems from the use of sunscreens with these nanomaterials.

Single and multispecies microalgae toxicological tests assessing the impact of several BPA analogues used by industry

BPA is a hazard for human and environmental health and recently BPA was added to the Candidate List of substances of very high concern by European Chemical Agency (ECHA). In accordance with this proposal, the authorities have encouraged the replacement of BPA by BPA analogues; however, little is known about the impact of these compounds on the environment. Due to this situation five BPA analogues (BPS, BPAP, BPAF, BPFL and BPC) were chosen in order to study their effects on marine primary producers. Three marine microalgae species (Phaeodactylum tricornutum, Tetraselmis suecica and Nannochloropsis gaditana) were selected for single and multispecies tests concerning the ecotoxicological effects of these BPA analogues. Microalgae were exposed to BPs over 72 h at different dosages (5, 20, 40, 80, 150 and 300 μM). Responses such as: growth, ROS production, cell complexity, cell size, autofluorescence of chlorophyll a, effective quantum yield of PSII and pigment concentrations were assessed at 24, 48 and 72 h. The results revealed that BPS and BPA showed lower toxicity to microalgae in comparison with BPFL > BPAF > BPAP and >BPC for the endpoints studied. N. gaditana was the least sensitive microalgae in comparison to P. tricornutum and T. suecica. However, a different trend was found in the multispecies tests where T. suecica dominated the microalgae community in relation to N. gaditana and P. tricornutum. The results of this work revealed for first time that present day BPA analogues are a threat and not a safe substitute for BPA in terms of the marine phytoplanktonic community. Therefore, the results of their impact on aquatic organisms should be shared.

Effect of TiO2 Microparticles in Lettuce (Lactuca sativa L.) Seeds and Seedlings

The particle size reduction technology is used in several segments, including sunscreens and new techniques and product improvement. One of the main particles used in the sunscreens formulation is titanium dioxide (TiO2). This formulation allows for better characteristics of these products. Perspectives like incorporation of the particles by other biological systems beyond humans and their effects should be observed. This work aimed to evaluate the titanium dioxide microparticles phytotoxicity on Lactuca sativa L. plants through tests of germination, growth, and weight analysis using microscopy techniques: optical microscopy (OM) and scanning electron microscopy (SEM). Some of the results showed cellular and morphological damage, mainly in the roots and 50 mg L-1 TiO2 concentration, confirmed by SEM. Additionally, anatomical damages like vascular bundle disruption and irregularity in the cortex cells were confirmed by SEM. Additionally, anatomical damages were observed on the three main organs (root, hypocotyl, and leaves) evidenced by the OM. Perspectives to confirm new hypotheses of the interaction of nanomaterials with biological systems are necessary.

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.

Effects of TiO2 and ZnO nanoparticles on the growth of phytoplankton assemblages in seawater

Compounds in sunscreen such as ultraviolet (UV) filters protect human skin from damage caused by UV radiation exposure. However, sunscreen components reach marine ecosystems after their release from human skin during activities such as swimming and washing, and are potentially toxic to marine organisms. TiO₂ and ZnO nanoparticles (NPs) are commonly used as inorganic UV filters. In this study, we explored the effects of TiO₂ and ZnO NPs on natural phytoplankton assemblages in coastal seawater. Growth rates of natural phytoplankton assemblages were significantly decreased by 10 mg L^-1 TiO₂ and 1 and 10 mg L^-1 ZnO NP treatments. NP addition also modified the size structure of phytoplankton assemblages, and small phytoplankton (mainly cyanobacteria) are vulnerable to NPs. Because herbivore food preferences depend strongly on algal cell size, NP contamination could also affect higher trophic levels. Notably, small phytoplankton are an important component in microbial loop, and this energy transfer pathway may be more vulnerable to NP contamination.

Modelling the bioconcentration of Zn from commercial sunscreens in the marine bivalve Ruditapes philippinarum

Sunscreens contain ZnO particles used as a UV filter cause adverse effects in the marine environment through the release of this metal into seawater and its bioaccumulation in organisms. A mathematical model using sunscreen colloidal residues, seawater and R. philippinarum clams as differentiated compartments, is proposed in order to interpret both the kinetic pattern and the bioaccumulation of Zn in clams. Two kinetic laboratory experiments were conducted, both with and without clams exposed to sunscreen concentrations from 0 to 200 mg L^-1. Both the lowest value of uptake rate coefficient obtained when 5 mg L^-1 of sunscreen is added (0.00688 L g^-1 d^-1) and the highest obtained at sunscreen addition of 100 mg L^-1 (0.0670 L g^-1 d^-1), predict a lower bioavailability of Zn in a complex medium such as the seawater-sunscreen mixtures, in comparison to those studied in the literature. The efflux rate coefficient from clams to seawater increased from 0 to 0.162 d^-1 with the sunscreen concentrations. The estimated value of the inlet rate coefficient at all studied concentrations indicates that there is a negligible colloidal Zn uptake rate by clams, probably due to the great stability of the organic colloidal residue. An equilibrium shift to higher values of Zn in water is predicted due to the bioconcentration of Zn in clams. The kinetic model proposed with no constant Zn (aq) concentrations may contribute to a more realistic prediction of the bioaccumulation of Zn from sunscreens in clams.

Nano-ecotoxicology in a changing ocean

The ocean faces an era of change, driven in large by the release of anthropogenic CO2, and the unprecedented entry of pollutants into the water column. Nanomaterials, those particles < 100 nm, represent an emerging contaminant of environmental concern. Research on the ecotoxicology and fate of nanomaterials in the natural environment has increased substantially in recent years. However, commonly such research does not consider the wider environmental changes that are occurring in the ocean, i.e., ocean warming and acidification, and occurrence of co-contaminants. In this review, the current literature available on the combined impacts of nanomaterial exposure and (i) ocean warming, (ii) ocean acidification, (iii) co-contaminant stress, upon marine biota is explored. Here, it is identified that largely co-stressors influence nanomaterial ecotoxicity by altering their fate and behaviour in the water column, thus altering their bioavailability to marine organisms. By acting in this way, such stressors, are able to mitigate or elevate toxic effects of nanomaterials in a material-specific manner. However, current evidence is limited to a relatively small set of test materials and model organisms. Indeed, data is biased towards effects upon marine bivalve species. In future, expanding studies to involve other ecologically significant taxonomic groups, primarily marine phytoplankton will be highly beneficial. Although limited in number, the available evidence highlights the importance of considering co-occurring environmental changes in ecotoxicological research, as it is likely in the natural environment, the material of interest will not be the sole stressor encountered by biota. As such, research examining ecotoxicology alongside co-occurring environmental stressors is essential to effectively evaluating risk and develop effective long-term management strategies.

Metabolic alterations in alga Chlamydomonas reinhardtii exposed to nTiO2 materials

Nano-sized titanium dioxide (nTiO2) is one of the most commonly used materials, however the knowledge about the molecular basis for metabolic and physiological changes in phytoplankton is yet to be explored. In the present study we use a combination of targeted metabolomics, transcriptomics and physiological response studies to decipher the metabolic perturbation in green alga Chlamydomonas reinhardtii exposed for 72 h to increasing concentrations (2, 20, 100 and 200 mg L-1) of nTiO2 with primary sizes of 5, 15 and 20 nm. Results show that the exposure to all three nTiO2 materials induced perturbation of the metabolism of amino acids, nucleotides, fatty acids, tricarboxylic acids, antioxidants but not in the photosynthesis. The alterations of the most responsive metabolites were concentration and primary size-dependent despite the significant formation of micrometer-size aggregates and their sedimentation. The metabolic perturbations corroborate the observed physiological responses and transcriptomic results and confirmed the importance of oxidative stress as a major toxicity mechanism for nTiO2. Transcriptomics revealed also an important influence of nTiO2 treatments on the transport, adenosine triphosphate binding cassette transporters, and metal transporters, suggesting a perturbation in a global nutrition of the microalgal cell, which was most pronounced for exposure to 5 nm nTiO2. The present study provides for the first-time evidence for the main metabolic perturbations in green alga C. reinhardtii exposed to nTiO2 and helps to improve biological understanding of the molecular basis of these perturbations.

Environmental Fate of Metal Nanoparticles in Estuarine Environments

In the last decade, metal engineered nanomaterials (ENMs) have seen an exponential use in many critical technologies and products, as well an increasing release into the environment. Coastal ecosystems worldwide may receive ENM-polluted waters and wastes, with a consequent alteration of habitats and contamination of aquatic biota. There is a scarcity of data regarding the fate of these emerging contaminants in such environments. Open issues include the determination of the sources, the quantification of the interactions with marine sediments, the bioaccumulation pathways, the ecotoxicology on marine fauna and the identification of the principal biotic and abiotic factors that may alter metal ENMs toxicity. Little is known about their potential transference into the food web, as well toxicity features and co-stressors of single or multiple ENMs under laboratory and real environmental conditions for various taxonomic phyla. This review reports current knowledge on the ecological impact of ENMs under the complex environmental conditions of estuary systems, identifies gaps in current knowledge and provides directions for future research.

Transport of nanoparticulate TiO2 UV-filters through a saturated sand column at environmentally relevant concentrations

The fate of sunscreen residues released during bathing activities around recreational areas is an emerging concern regarding the potential ecotoxicity of some of their ingredients, including nanoparticulate TiO₂ UV-filters. To assess the extent of contamination in the natural medium, sand-packed column experiments were carried out with bare TiO₂ engineered nanoparticles (ENPs) and two commercial nano-TiO₂ UV-filters coated with either SiO₂ (hydrophilic) or a combination of Al₂O₃ and simethicone (amphiphilic). The high sensitivity of (single particle)ICPMS online monitoring of the breakthrough curves made it possible to inject the ENPs at trace levels (2-100 μg L^-1) in eluents composed of 10^-3 and 10^-2 M NaCl and pHs of 5.7 and 7.8. The deposition of all ENPs in the sand increased with the ionic strength and decreased with the pH of the carrier. Both bare and SiO₂-coated ENPs showed a clear control by the electrostatic interactions between the particles and the quartz grains surfaces, in partial agreement with classical DLVO theory. Unexpectedly high rates of transfer were observed with the amphiphilic UV-filter, which could be explained by the addition of a contribution to the DLVO model to account for the steric repulsion between the sand collector and the polysiloxane surface layer of this ENP. These results demonstrate the major role played by the coating of UV-filters regarding their fate in porous media like soils, sediments and aquifers.

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.

Ecotoxicological Evaluation of Sunscreens on Marine Plankton

In recent years, a large number of sunscreens have emerged to protect our skin. Most of them are made up of simple or compound aromatic structures, which can pose a threat to marine ecosystems. In order to understand their effects on the marine environment, different ecotoxicological bioassays were carried out using planktonic organisms from three phyla and two different trophic levels: larvae of the sea urchin Paracentrotus lividus, the copepod Acartia tonsa, and the microalga Tisochrysis lutea. The aim of these tests was to expose these organisms to leachates from eight sunscreen formulations. All of them showed a great variability in toxicity on the different plankton organisms. The highest toxicity level was found for cream number 4 when tested on sea urchin, exhibiting an EC50 = 122.4 mg/L. The toxicity of the UV filter 2-phenyl-5-benzimidazolesulfonic acid, exclusively present in that cream, was evaluated in sea urchin, where an EC10 = 699.6 mg/L was obtained under light exposure. According to our results, all tested creams become nontoxic to plankton upon 30,000-fold dilution in seawater; thus, only local effects are expected. This study highlights the need to understand the toxic effects generated by solar protection products, as well as their ingredients, on marine organisms.

The ancillary effects of nanoparticles and their implications for nanomedicine

Nanoparticles are often engineered as a scaffolding system to combine targeting, imaging and/or therapeutic moieties into a unitary agent. However, mostly overlooked, the nanomaterial itself interacts with biological systems exclusive of application-specific particle functionalization. This nanoparticle biointerface has been found to elicit specific biological effects, which we term 'ancillary effects'. In this Review, we describe the current state of knowledge of nanobiology gleaned from existing studies of ancillary effects with the objectives to describe the potential of nanoparticles to modulate biological effects independently of any engineered function; evaluate how these effects might be relevant for nanomedicine design and functional considerations, particularly how they might be useful to inform clinical decision-making; identify potential clinical harm that arises from adverse nanoparticle interactions with biology; and, finally, highlight the current lack of knowledge in this area as both a barrier and an incentive to the further development of nanomedicine.

Silver nanoparticles (AgNPs) internalization and passage through the Lactuca sativa (Asteraceae) outer cell wall

Silver nanoparticle (AgNPs) toxicity is related to nanoparticle interaction with the cell wall of microorganisms and plants. This interaction alters cell wall conformation with increased reactive oxygen species (ROS) in the cell. With the increase of ROS in the cell, the dissolution of zero silver (Ag0) to ionic silver (Ag+) occurs, which is a strong oxidant agent to the cellular wall. AgNP interaction was evaluated by transmission electron microscopy (TEM) on Lactuca sativa roots, and the mechanism of passage through the outer cell wall (OCW) was also proposed. The results suggest that Ag+ binds to the hydroxyls (OH) present in the cellulose structure, thus causing the breakdown of the hydrogen bonds. Changes in cell wall structure facilitate the passage of AgNPs, reaching the plasma membrane. According to the literature, silver nanoparticles with an average diameter of 15nm are transported across the membrane into the cells by caveolines. This work describes the interaction between AgNPs and the cell wall and proposes a transport model through the outer cell wall.

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.

Cytotoxicity and genotoxicity of coated-gold nanoparticles on freshwater algae Pseudokirchneriella subcapitata

Gold engineered nanoparticles (nAu) are increasingly detected in ecosystems, and this raises the need to establish their potential effects on aquatic organisms. Herein, cytotoxic and genotoxic effects of branched polyethylenimine (BPEI)- and citrate (cit)-coated nAu (5, 20, and 40 nm) on algae Pseudokirchneriella subcapitata were evaluated. The apical biological endpoints: growth inhibition and chlorophyll a (Chl a) content were investigated at 62.5-1000 µg/L over 168 h. In addition, the apurinic/apyrimidinic (AP) sites, randomly amplified polymorphic deoxyribonucleic acid (RAPD) profiles, and genomic template stability (GTS) were assessed to determine the genotoxic effects of nAu. The results show algal growth inhibition at 5 nm BPEI-nAu up to 96 h, and thereafter cell recovery except at the highest concentration of 1000 µg/L. Insignificant growth reduction for cit-nAu (all sizes), as well as 20 and 40 nm BPEI-nAu, was observed over 96 h, but growth promotion was apparent at all exposures thereafter except for 40 nm BPEI-nAu at 250 µg/L. A decrease in Chl a content following exposure to 5 nm BPEI-nAu at 1000 µg/L corresponded to significant algal growth reduction. In genotoxicity studies, a significant increase in AP sites content was observed relative to the control - an indication of nAu ability to induce genotoxic effects irrespective of their size and coating type. For 5 nm- and 20 nm-sized nAu for both coating types and exposure concentrations no differences in AP sites content were observed after 72 and 168 h. However, a significant reduction in AP sites was observed following algae exposure to 40 nm-sized nAu (irrespective of coating type and exposure concentration) at 168 h compared to 72 h. Thus, AP sites results at 40 nm-size suggest likely DNA damage recovery over a longer exposure period. The findings on AP sites content showed a good correlation with an increase in genome template stability and growth promotion observed after 168 h. In addition, RAPD profiles demonstrated that nAu can induce DNA damage and/or DNA mutation to P. subcapitata as evidenced by the appearance and/or disappearance of normal bands compared to the controls. Therefore, genotoxicity results revealed significant toxicity of nAu to algae at the molecular level although no apparent effects were detectable at the morphological level. Overall, findings herein indicate that long-term exposure of P. subcapitata to low concentrations of nAu may cause undesirable sub-lethal ecological effects.

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.

Toxicity of bisphenol A on marine microalgae: Single- and multispecies bioassays based on equivalent initial cell biovolume

Standardised microalgal toxicity assays are usually carried out with single-species cultures; however, multispecies bioassays are more faithful to environmental conditions. The aim of this study was to assess the toxicity of the emerging pollutant bisphenol A (BPA) in single- and multispecies bioassays with three marine microalgae (Tetraselmis suecica, Phaeodactylum tricornutum and Nannochloropsis gaditana) using an equivalent initial cell biovolume of each species. After conducting preliminary growth experiments on these microalgae, a BPA concentration of 1 mg L^-1 was chosen to study the effects of this pollutant in uni- and multialgal cultures. Growth, cell viability, oxidative stress, and inherent cell properties (size, complexity and autofluorescence) were determined by flow cytometry after 24 h of exposure. Results showed that P. tricornutum was the most affected species in all analysed biomarkers in both single- and multispecies bioassays. However, in N. gaditana cultures no significant differences were observed in any of the parameters and conditions tested, indicating that this species was the least sensitive to BPA. Between the uni- and multialgal tests, significant differences were observed in controls and BPA treated cultures of P. tricornutum and T. suecica. Nevertheless, it seemed that the cells of these marine microalgae suffered a similar pattern of alterations in both toxicity tests.

Environmentally relevant concentrations of titanium dioxide nanoparticles pose negligible risk to marine microbes

Nano-sized titanium dioxide (nTiO₂) represents the highest produced nanomaterial by mass worldwide and, due to its prevalent industrial and commercial use, it inevitably reaches the natural environment. Previous work has revealed a negative impact of nTiO₂ upon marine phytoplankton growth, however, studies are typically carried out at concentrations far exceeding those measured and predicted to occur in the environment currently. Here, a series of experiments were carried out to assess the effects of both research-grade nTiO₂ and nTiO₂ extracted from consumer products upon the marine dominant cyanobacterium, Prochlorococcus, and natural marine communities at environmentally relevant and supra-environmental concentrations (i.e., 1 μg L^-1 to 100 mg L^-1). Cell declines observed in Prochlorococcus cultures were associated with the extensive aggregation behaviour of nTiO₂ in saline media and the subsequent entrapment of microbial cells. Hence, higher concentrations of nTiO₂ particles exerted a stronger decline of cyanobacterial populations. However, within natural oligotrophic seawater, cultures were able to recover over time as the nanoparticles aggregated out of solution after 72 h. Subsequent shotgun proteomic analysis of Prochlorococcus cultures exposed to environmentally relevant concentrations confirmed minimal molecular features of toxicity, suggesting that direct physical effects are responsible for short-term microbial population decline. In an additional experiment, the diversity and structure of natural marine microbial communities showed negligible variations when exposed to environmentally relevant nTiO₂ concentrations (i.e., 25 μg L^-1). As such, the environmental risk of nTiO₂ towards marine microbial species appears low, however the potential for adverse effects in hotspots of contamination exists. In future, research must be extended to consider any effect of other components of nano-enabled product formulations upon nanomaterial fate and impact within the natural environment.

Toxicity assessment of synthesized titanium dioxide nanoparticles in fresh water algae Chlorella pyrenoidosa and a zebrafish liver cell line

This study aims to assess the toxicity of the commonly-spread titanium dioxide nanoparticles (TiO₂ NPs) by evaluating the exposure impact of the particles on both freshwater algae Chlorella pyrenoidosa and zebrafish liver cell line (ZFL), the two common in vitro models in toxicological studies. To compare the toxic effects of TiO₂ NPs with different physiochemical properties, three types of manufactured TiO₂ were used: bulk TiO₂, Degussa P25 TiO₂, and ultrafine TiO₂ NPs. Both short and long-term biological responses of green algae, such as the effect on the cell growth rate, pigment autofluorescence, and esterase activity were investigated. The dosage, physical property of TiO₂ particles, and their interactions with algal cells affect cellular growth, especially after short-term exposure. The hydrodynamic size plays a critical role in determining the acute toxicity to C. pyrenoidosa in terms of autofluorescence and esterase activity, while all types of TiO₂ NPs show toxic effects after exposure for 14 days. However, this observation is not seen when studying the effect of introduced particles in ZFL, for the precipitated Degussa P25 TiO₂ showed the highest cellular inhibition. Interestingly, despite the obvious overall toxicity toward C. pyrenoidosa, the photocatalytical properties of TiO₂ NPs may contribute to the enhanced photosynthesis in the low concentration range (<40 µg mL^-1). Overall, we found that the physical interactions between TiO₂ particles and the cells, particles' size and dispersibility play critical role in the cytotoxic effect for both algal and ZFL cells, while the photocatalytical properties of TiO₂ particles may produce mixed effects on the cytotoxicity of green algae.

Antibiotic tetracycline enhanced the toxic potential of photo catalytically active P25 titanium dioxide nanoparticles towards freshwater algae Scenedesmus obliquus

Titanium dioxide nanoparticles (TiO2 NPs) often co-exist with the other co-contaminants like antibiotics. The antibiotics can potentially modify the toxic effects of the co-contaminants like the NPs in the environment. Hence, the present study aims to understand the toxic potential of a binary mixture of tetracycline (TC) and TiO2 NPs to a model freshwater alga - Scenedesmus obliquus. Since, TiO2 NPs are known to be photo-catalytically active, non-irradiated (NI-TiO2 NPs), UVA pre-irradiated (UVA-TiO2 NPs), and UVB pre-irradiated (UVB-TiO2 NPs) TiO2 NPs was mixed separately with TC and their toxicity evaluated. It was observed that the cell viability for the three experimental groups decreased significantly (p < 0.001) with respect to the individual NPs-treated algae. Abbott's model suggested that the interaction between TC and Ni-TiO2 NPs was additive for all the concentrations of NI-TiO2 NPs tested. However, in the case of both the UV pre-irradiated NPs, the interaction was additive for the lower concentration (1.56 μM) and synergistic for both the higher concentrations (3.13, and 6.26 μM). At the concentrations tested the cell membrane damage and intracellular uptake of NPs increased significantly (p < 0.05) for the mixture in comparison with the individual NPs treated algae. This study suggested that even a non-lethal concentration of TC (EC10 = 0.135 μM) increased the toxic potential of the TiO2 NPs significantly and when this antibiotic was used in combination with the UV pre-irradiated NPs, toxicity even increased to a higher level.

Visible light. Part II: Photoprotection against visible and ultraviolet light

Cutaneous photobiology studies have focused primarily on the ultraviolet portion of the solar spectrum. Visible light (VL), which comprises 50% of the electromagnetic radiation that reaches the Earth's surface and, as discussed in Part I of this CME, has cutaneous biologic effects, such as pigment darkening and erythema. Photoprotection against VL includes avoiding the sun, seeking shade, and using photoprotective clothing. The organic and inorganic ultraviolet filters used in sunscreens do not protect against VL, only tinted sunscreens do. In the United States, these filters are regulated by the Food and Drug Administration as an over-the-counter drug and are subject to more stringent regulations than in Europe, Asia, and Australia. There are no established guidelines regarding VL photoprotection. Alternative measures to confer VL photoprotection are being explored. These novel methods include topical, oral, and subcutaneous agents. Further development should focus on better protection in the ultraviolet A1 (340-400 nm) and VL ranges while enhancing the cosmesis of the final products.

Release and fate of nanoparticulate TiO2 UV filters from sunscreen: Effects of particle coating and formulation type

Nanoparticulate mineral UV filters, such as titanium dioxide (TiO₂) nanocomposites, are being increasingly used in sunscreens as an alternative to organic UV filters. However, there is still a lack of understanding regarding their fate and behavior in aquatic environments and potential environmental impacts after being released from a bather's skin during recreational activities. In this work, we assessed the release, fate, and transformation of two commercial nanocomposite TiO₂ UV filters, one hydrophobic and one hydrophilic, in ultrapure water and simulated fresh- and seawater. The hydrophobic TiO₂ nanocomposite, T-SA, was coated with a primary Al₂O₃ photopassivation layer and a secondary stearic acid layer, while the hydrophilic TiO₂ nanocomposite, T-SiO₂, was coated with a single SiO₂ photopassivation layer. The influence of the sunscreen formulation was examined by dispersing the TiO₂ nanocomposites in their typical continuous phase (i.e., oil for T-SA and water for T-SiO₂) before introduction into the aqueous system. After 48 h of aqueous aging and 48 h of settling, 88-99% of the hydrophobic T-SA remained floating on top of the water column in all aqueous systems. On the other hand, 100% of the hydrophilic T-SiO₂ settled out of the water column in the fresh- and seawaters. With respect to the photopassivation coatings, no loss of the T-SA Al₂O₃ layer was detected after aqueous aging, but 99-100% dissolution of the SiO₂ layer on the T-SiO₂ nanocomposite was observed after 48 h in the fresh- and seawaters. This dissolution left behind T-SiO₂ by-products exhibiting a photocatalytic activity similar to that of bare rutile TiO₂. Overall, the results demonstrated that the TiO₂ surface coating and sunscreen formulation type drive environmental behavior and fate and that loss of the passivation layer can result in potentially harmful, photoactive by-products. These insights will help guide regulations and assist manufacturers in developing more environmentally safe sunscreens.

Green photocatalytic disinfection of real sewage: efficiency evaluation and toxicity assessment of eco-friendly TiO2-based magnetic photocatalyst under solar light

To evaluate the green photocatalytic disinfection for practical applications, disinfection of different types of real sewage using magnetic photocatalyst RGO/Fe,N-TiO₂/Fe₃O₄@SiO₂ (RGOFeNTFS) under simulated solar light was investigated: low-salinity sewage after tertiary treatment, low-salinity sewage after secondary biological treatment, high-salinity sewage after secondary biological treatment, and high-salinity sewage after chemically enhanced primary treatment. The classification of the sewage as high and low-salinity is based on the regions of sewage source that use seawater and freshwater for toilet flushing, respectively. It shows potential of solar-light-driven photocatalytic disinfection in low-salinity sewage: around 20 min (for sewage after tertiary treatment) and 45 min (for sewage after secondary treatment) of photocatalytic disinfection are required for sewage to meet the discharge standard, and no bacterial regrowth is observed in the treated sewage after 48 h. However, due to the poorer water quality, the high-salinity sewage requires a relatively long reaction time (more than 240 min) to meet the discharge standard, showing minimal practical significance. Further, the complex characteristics of real sewage, such as organic matter, suspended matter, multivalent-ions, pH and DO level significantly influence photocatalytic disinfection, and should be carefully reviewed in evaluating the photocatalytic disinfection of sewage. Besides, RGOFeNTFS shows a good reusability over three cycles for photocatalytic disinfection of low-salinity sewage samples. Moreover, the non-toxicity, indicated by phytoplankton in seawater, of both RGOFeNTFS (<= 3 g/L) and treated low-salinity sewage demonstrates the feasibility of the practical application of photocatalytic disinfection using RGOFeNTFS under irradiation of solar light.

Biochar-mediated transformation of titanium dioxide nanoparticles concerning TiO2NPs-biochar interactions, plant traits and tissue accumulation to cell translocation

Titanium dioxide nanoparticles (TiO₂NPs) application in variety of commercial products would likely release these NPs into the environment. The interaction of TiO₂NPs with terrestrial plants upon uptake can disturb plants functional traits and can also transfer to the food chain members. In this study, we investigated the impact of TiO₂NPs on wheat (Triticum aestivum L.) plants functional traits, primary macronutrients assimilation, and change in the profile of bio-macromolecule. Moreover, the mechanism of biochar-TiO₂NPs interaction, immobilization, and tissue accumulation to cell translocation of NPs in plants was also explored. The results indicated that the contents of Ti in wheat tissues was reduced about 3-fold and the Ti transfer rate (per day) was reduced about 2 fold at the 1000 mg L^-1 exposure level of TiO₂NPs in biochar amended exposure medium. Transmission electron microscopy (TEM) with elemental mapping confirmed that Ti concentrated in plant tissues in nano-form. The interactive effect of TiO₂NPs + biochar amendment on photosynthesis related and gas exchange traits was observed at relatively low TiO₂NPs exposure level (200 mg L^-1), which induced the positive impact on wheat plants proliferation. TiO₂NPs alone exposure to wheat also modified the plant's bio-macromolecules profile with the reduction in the assimilation of primary macronutrients, which could affect the food crop nutritional value and quality. X-ray photoelectron spectroscopy (XPS) chemical analysis of biochar + TiO₂NPs showed an additional peak, which indicated the binding interaction of NPs with biochar. Moreover, Fourier-transform infrared (FTIR) spectroscopy confirmed that the biochar carboxyl group is the main functionality involved in the bonding process with TiO₂NPs. These findings will help for a mechanistic understanding of the role of biochar in the reduction of NPs bioavailability to primary producers of the terrestrial environment.

An overview of the internalization and effects of microplastics and nanoplastics as pollutants of emerging concern in bivalves

Microplastic and nanoplastic pollution in aquatic environments is a topic of emerging concern due to the internalization, retention time and effects of these particles in aquatic biota. Bivalves are considered bioindicators due to their wide distribution, sessile behaviour, occupation of ecological niches and ability to filter a large water volume. The study of microplastics and nanoplastics in bivalves has revealed the uptake mechanisms, internalization, distribution and depuration of these particles as well as their effects on physiological parameters, morphological alterations, immunotoxicity and changes in gene expression and proteomic profiles. In this review, we examine the primary characteristics of microplastics and nanoplastics (type of material, size, coating, density, additives and shapes) involved in their possible toxicity in bivalves. Furthermore, secondary characteristics such as the suspension media, aggregation stage and adsorption of persistent pollutants were also recorded to assess the impact of these materials on bivalves. Here, we have highlighted the efforts exerted thus far and the remaining gaps in understanding the extent of microplastic and nanoplastic impacts on bivalves on the basis of laboratory experiments and mesocosm bioassays and in the field. Furthermore, further microplastic and nanoplastic toxicological studies are proposed to facilitate the realistic assessment of environmental risk.

Robust natural ultraviolet filters from marine ecosystems for the formulation of environmental friendlier bio-sunscreens

Ultraviolet radiation (UVR) has detrimental effects on human health. It induces oxidative stress, deregulates signaling mechanisms, and produces DNA mutations, factors that ultimately can lead to the development of skin cancer. Therefore, reducing exposure to UVR is of major importance. Among available measures to diminish exposure is the use of sunscreens. However, recent studies indicate that several of the currently used filters have adverse effects on marine ecosystems and human health. This situation leads to the search for new photoprotective compounds that, apart from offering protection, are environmentally friendly. The answer may lie in the same marine ecosystems since molecules such as mycosporine-like amino acids (MAAs) and scytonemin can serve as the defense system of some marine organisms against UVR. This review will discuss the harmful effects of UVR and the mechanisms that microalgae have developed to cope with it. Then it will focus on the biological distribution, characteristics, extraction, and purification methods of MAAs and scytonemin molecules to finally assess its potential as new filters for sunscreen formulation.

Occurrence and Distribution of UV Filters in Beach Sediments of the Southern Baltic Sea Coast

The interest in UV filters’ occurrence in the environment has increased since they were recognized as “emerging contaminants” having potentially adverse impacts on many ecosystems and organisms. Increased worldwide demand for sunscreens is associated with temperature anomalies, high irradiance, and changes in the tourist market. Recently, it has been demonstrated that personal care products, including sunscreens, appear in various ecosystems and geographic locations causing an ecotoxicological threat. Our goal was to determine for the first time the presence of selected organic UV filters at four beaches in the central Pomeranian region in northern Poland and to assess their horizontal and vertical distribution as well as temporal variation at different locations according to the touristic pressure. In this pioneering study, the concentration of five UV filters was measured in core sediments dredged from four exposed beaches (Darłowo, Ustka, Rowy, and Czołpino). UV filters were detected in 89.6% of collected cores at detection frequencies of 0–22.2%, 75–100%, 0–16.7%, and 2.8–25% for benzophenone-1 (BP-1), benzophenone-2 (BP-2), benzophenone-3 (BP-3), and enzacamene (4-MBC), respectively. In terms of seasonality, the concentration of UV filters generally increased in the following order: summer > autumn > spring. No detectable levels of 3-BC (also known as 3-benzylidene camphor) were recorded. No differences were found in the concentration of UV filters according to the depth of the sediment core. During the summer and autumn seasons, all UV filters were detected in higher concentrations in the bathing area or close to the waterline than halfway or further up the beach. Results presented in this study demonstrate that the Baltic Sea coast is not free from UV filters. Even if actual concentrations can be quantified as ng·kg−1 causing limited environmental threat, much higher future levels are expected due to the Earth’s principal climatic zones shifting northward.

The interactive effects of titanium dioxide nanoparticles and light on heterotrophic bacteria and microalgae associated with marine aggregates in nearshore waters

Titanium dioxide nanoparticles (n-TiO₂) are emerging contaminants and the ecological impact of these materials to the nearshore environment is largely unknown. The reactivity of n-TiO₂ increases with light exposure, and the photocatalytic effects have been shown on cultures of bacteria and microalgae in the laboratory. The purpose of this study was to assess the response of natural bacterial and microalgal communities associated with marine aggregates to n-TiO₂ under conditions similar to those found in the photic zone of nearshore waters. Nano and bulk TiO₂ particles were incorporated into marine aggregates over 4 days under two light conditions: 6:18 and 0:24 (hours light:dark). The abundance and metabolic response of heterotrophic bacteria and viability of microalgae associated with aggregates were assessed. Although the proportion of living microalgae was unchanged, the abundance, total metabolic activity and functional diversity of heterotrophic bacteria were significantly altered by irradiated n-TiO₂.

Repellency and mortality effects of sunscreens on the shrimp Palaemon varians: Toxicity dependent on exposure method

Contamination by sunscreens has become a serious environmental problem due to the increasing use of these products in coastal regions. Their complex chemical composition supposes an input of different chemical compounds capable of producing toxic effects and repelling organisms. The aim of the current study was to experimentally check the repellency of three commercial sunscreens [A (lotion), B (gel) and C (milk spray)] by assessing the escape (displacement towards areas with lower sunscreen levels) of the estuarine shrimp Palaemon varians exposed (4 h) to a gradient (0-300 mg/L) of the sunscreens in a heterogeneous non-forced exposure scenario. Additionally, mortality and immobility (72 h) were checked in a traditional forced exposure scenario. Considering that the toxicity of sunscreens is a little controversial regarding their chemical availability in the medium, two different methods of sunscreen solubilisation were tested: complete homogenization and direct immersion. Very low mortality was observed in the highest concentration of sunscreens A and C applied by direct immersion; however, for sunscreen B, the main effect was the loss of motility when homogenization was applied. Repellency was evidenced for two sunscreens (A and B) applied by direct immersion. The homogenization in the medium seemed to lower the degree of repellency of the sunscreens, probably linked to the higher viscosity in the medium, preventing the motility of shrimps. By integrating both short-term responses (avoidance and mortality/immobility), the PID (population immediate decline) calculated showed that avoidance might be the main factor responsible for the reduction of the population at the local scale.

Assessing UV filter inputs into beach waters during recreational activity: A field study of three French Mediterranean beaches from consumer survey to water analysis

In order to assess the release of UV filters from the sunscreen used by beachgoers into seawater within the bathing zone, a field campaign was carried out during the summer of 2017 at three beaches in Marseille, along the French Mediterranean coast. A social survey analyzed beachgoer attendance, the quantities and types of suncare products used and the bathing frequencies, while the bathing water was analyzed spatially and temporally so as to quantify both mineral and organic UV filters directly released and recovered. During the peak recreational time at the three beaches, both mineral and organic UV filters were detected in higher concentrations in the bathing area than offshore. In general, higher concentrations were recovered in the water top surface layer than in the water column, giving respectively 100-900 and 20-50 μg/L for TiO₂, 10-15 and 1-3 μg/L for ZnO, 40-420 and 30-150 ng/L for octocrylene, and 10-15 and 10-350 ng/L for avobenzone. More than 75% of the 471 interviewees reported bathing every time they go to the beach, with 68% using a suncare product 2.6 times on average. From these data we estimated that an average mass of 52 kg/day or 1.4 t/month of suncare products are possibly released into bathing water for a beach attended by 3000 people daily. The mass ratio of UV filters in such products typically ranges from 0.03 to 0.1, allowing us to propose theoretical maximum concentrations in the beach water. Our recovery of measured UV filter concentrations in seawater compared to the theoretical concentrations revealed two distinct scenarios for the mineral and organic filters. While up to 49% of the mineral filters used by beachgoers may be released into the seawater, the organic filters were minimally recovered in the environment, most likely due to internalization through the skin barrier or partial photodegradation.

Sunscreens as a New Source of Metals and Nutrients to Coastal Waters

Studies detailing the environmental impact of sunscreen products on coastal ecosystems are considered a high priority. In the present study, we have determined the release rate of dissolved trace metals (Al, Cd, Cu, Co, Mn, Mo, Ni, Pb, and Ti) and inorganic nutrients (SiO₂, P-PO₄^3-, and N-NO₃^-) from a commercial sunscreen in seawater, and the role of UV radiation in the mobilization of these compounds. Our results indicate that release rates are higher under UV light conditions for all compounds and trace metals except Pb. We have developed a kinetic model to establish the release pattern and the contribution to marine coastal waters of dissolved trace metals and inorganic nutrients from sunscreen products. We conservatively estimate that sunscreen from bathers is responsible for an increase of dissolved metals and nutrients ranging from 7.54 × 10^-4 % for Ni up to 19.8% for Ti. Our results demonstrate that sunscreen products are a significant source of metals and inorganic nutrients to coastal waters. The normally low environmental concentrations of some elements (e.g., P) and the toxicity of others (e.g., Pb) could be having a serious adverse effect on marine ecology in the Mediterranean Sea. This risk must not be ignored.

A simple sensing of hazardous photo-induced superoxide anion radicals using a molecular probe in ZnO-Nanoparticles aqueous medium

The generation of reactive oxygen species (ROS) during the photolysis of sunscreens and sun blockers poses consumer safety concerns while necessitating proper identification and quantitation of ROS species. Here, a colorimetric sensing approach has been developed based on a molecular probe (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2-H-tetrazolium-5-carboxanilide (XTT) tetrazolium salt) to quantitatively measure the photo-induced superoxide anion radicals (O₂^.) generated from the photocatalysis of zinc oxide nanoparticles (ZnO-NPs) in aqueous solutions. Note that superoxide anion radicals are assumed to be the main reactive oxygen species (ROS) generated from such photocatalysis. The characterisation of ZnO-NPs before and after irradiation showed average particle sizes of 616.5 and 295.3 nm and ζ-potential values of 0 and -24.4 mV, respectively. It is hoped that this proposed protocol can be further developed to efficiently detect other ROS present in inorganic sun blockers and to optimize the utility of various sunscreen formulations.

Highly Electrophilic Titania Hole as a Versatile and Efficient Photochemical Free Radical Source

Photogenerated holes in nanometric semiconductors, such as TiO₂, constitute remarkable powerful electrophilic centers, capable of capturing an electron from numerous donors such as ethers, or nonactivated substrates like toluene or acetonitrile, and constitute an exceptionally clean and efficient source of free radicals. In contrast with typical free radical precursors, semiconductors generate single radicals (rather than pairs), where the precursors can be readily removed by filtration or centrifugation after use, thus making it a convenient tool in organic chemistry. The process can be described as an example of dystonic proton coupled electron transfer.

Massive coastal tourism influx to the Mediterranean Sea: The environmental risk of sunscreens

The Mediterranean region is, by far, the leading tourism destination in the world, receiving more than 330 million tourists in 2016. This tourism is undertaken mostly for seaside holidays, and during the summer season concentrates between 46% and 69% of the total international arrivals; this is equivalent to a density of 2.9 tourists per meter of Mediterranean coast, or double this number taking into account the local/permanent population in addition. Previous studies have reported not only the presence of sunscreen in the various environmental compartments (water, sediments and biota) of the Mediterranean Sea (MS) and other regions, but also show that sunscreen products are toxic for marine biota and are accumulated and biomagnificated. Here, we highlight that the environmental risk of these chemicals is likely to be exacerbated in the MS due to the massive influx of tourists and its densely populated coasts, the basin's limited exchanges with the ocean, the high residence time of surface waters, and its oligotrophic waters.

Synthesis of modified carbon dots with performance of ultraviolet absorption used in sunscreen

The research and development of non-toxic, broad-spectrum and environmentally friendly ultraviolet absorbers remains no significant progress in recent years. We found that the ultraviolet absorption spectra can be regulated through modification of functional groups on carbon dots surface, and the modified carbon dots exhibiting good stability and functions of sunscreen (Sun protection actor reaches to 22) and anti-aging properties were experimentally demonstrated. Moreover, we figured out the ultraviolet absorption mechanism of carbon dots for the first time and confirmed the existence of non-fluorescent radiation energy traps. Carbon dots are expected to be widely used and commercialized as ultraviolet absorbers.

Synthesis of Silicon Quantum Dots with Highly Efficient Full-Band UV Absorption and Their Applications in Antiyellowing and Resistance of Photodegradation

UV absorbers are very effective in the fields of antiyellowing, resistance of photocatalytic degradation, and sunscreen cosmetics. However, commercialized UV absorbers have the drawbacks of toxicity, low absorption efficiency, transparency, etc. Here, we report for the first time silicon quantum dots as full-band UV absorbers. The NH-refunctionalized silicon quantum dots with high-performance UV absorption were successfully synthesized under the synergistic effect of sodium citrate and ethanediamine, and the (NH, OH)-functionalized silicon quantum dots (SiQDs) with full-band UV absorption can be achieved by reregulating -NH₂ and -OH groups on the surface. The as-prepared (NH, OH)-functionalized SiQDs exhibited good stability and underwent treatment of varying pH and temperature. Furthermore, experimental results demonstrated that compared to commercial water-soluble organic UV absorbers, the (NH, OH)-functionalized SiQDs showed better antiyellowing performance for polyurethane and resistance of photocatalytic degradation for rhodamine B, and presented huge application potential in sunscreen cosmetics. Finally, the UV absorption mechanism of SiQDs was explained to be mainly related to Γ → Γ direct band gap transition, which absorb UV light and release it as thermal radiation.

Comparative effects of seawater acidification on microalgae: Single and multispecies toxicity tests

In order to gain knowledge about the potential effects of acidification in aquatic ecosystems, global change research based on microalgae as sentinel species has been often developed. However, these studies are limited to single species tests and there is still a research gap about the behaviour of microalgal communities under this environmental stressor. Thus, the aim of this study was to assess the negative effects of CO₂ under an ecologically realistic scenario. To achieve this objective, two types of toxicity tests were developed; i) single toxicity tests and ii) multispecies toxicity tests, in order to evaluate the effects on each species as well as the interspecific competition. For this purpose, three microalgae species (Tetraselmis chuii, Phaeodactylum tricornutum and Nannochloropsis gaditana) were exposed to two selected pH levels (7.4, 6.0) and a control (pH 8.0). The pH values were choosen for testing different scenarios of CO₂ enrichment including the exchange atmosphere-ocean (pH 7.4) and natural or anthropogenic sources of CO₂ (pH 6.0). The effects on growth, cell viability, oxidative stress, plus inherent cell properties (size, complexity and autofluorescence) were studied using flow cytometry (FCM). Results showed that T. chuii was the most resistant species to CO₂ enrichment with less abrupt changes in terms of cell density, inherent cell properties, oxidative stress and cell viability. Although P. tricornutum was the dominant species in both single and multispecies tests, this species showed the highest decrease in cell density under pH 6.0. Effects of competence were recorded in the multispecies control (pH 8) but this competence was eclipsed by the effects of low pH. The knowledge of biological interactions made by different microalgae species is a useful tool to extrapolate research data from laboratory to the field.

Toxicity and mechanisms of action of titanium dioxide nanoparticles in living organisms

Titanium dioxide nanoparticles (TiO₂ NPs) are one of the most widely used nanomaterials in the consumer products, agriculture, and energy sectors. Their large demand and widespread applications will inevitably cause damage to organisms and ecosystems. A better understanding of TiO₂ NP toxicity in living organisms may promote risk assessment and safe use practices of these nanomaterials. This review summarizes the toxic effects of TiO₂ NPs on multiple taxa of microorganisms, algae, plants, invertebrates, and vertebrates. The mechanism of TiO₂ NP toxicity to organisms can be outlined in three aspects: The Reactive Oxygen Species (ROS) produced by TiO₂ NPs following the induction of electron-hole pairs; cell wall damage and lipid peroxidation of the cell membrane caused by NP-cell attachment by electrostatic force owing to the large surface area of TiO₂ NPs; and TiO₂ NP attachment to intracellular organelles and biological macromolecules following damage to the cell membranes.

The interactive effects of stratospheric ozone depletion, UV radiation, and climate change on aquatic ecosystems

Summary of current knowledge about effects of UV radiation in inland and oceanic waters related to stratospheric ozone depletion and climate change.