Toxicity of organic UV-filters to the aquatic midge Chironomus riparius

Interplay of UV-filter pollution and temperature rise scenarios on Mytilus galloprovincialis health: Unveiling sperm quality and adult physiology, biochemistry, and histology insights

Addressing the impacts of emerging contaminants within the context of climate change is crucial for understanding ecosystem health decline. Among these, the organic UV-filters 4-methylbenzylidenecamphor (4-MBC) and benzophenone-3 (BP-3) are widely used in cosmetics and personal care products. Their unique physico-chemical properties, along with their growing commercialization and consumption, have made them ubiquitous in aquatic environments through both direct and indirect releases, raising significant concerns about their potential threats to inhabiting biota. Additionally, increasing surface water temperatures exacerbate ecological risks, making it imperative to understand the implications for non-target species at different biological levels. This study investigated the short- and long-term effects of UV-filters 4-MBC or BP-3, at ecologically relevant concentrations, combined with current and predicted warming scenarios, on the performance and male reproductive health of Mytilus galloprovincialis mussel populations. Using biomarkers across sub-cellular, cellular, tissue, and individual levels, the study revealed significant physiological and biochemical impairments in both sperm cells and adults exposed to UV-filters. Temperature emerged as the primary driver influencing mussel responses and modulating the impacts of 4-MBC/BP-3, emphasizing their sensitivity to temperatures outside the optimal range and interactive effects between stressors. Specifically, sperm motility declined with increasing UV-filter concentrations, while temperature alone influenced ROS production, leading to compromised mitochondrial activity and DNA damage in the presence of combined stressors, indicative of potential reproductive impairments. Adults exhibited high UV-filter bioconcentration potential in whole tissues, compromised physiological status, morphophysiological changes in digestive glands, oxidative stress, and alterations in metabolic capacity, antioxidant defences, and biotransformation mechanisms, correlating with UV-filter exposure and temperature increase. Among the UV-filters tested, 4-MBC was the most detrimental, especially when combined with warming. Overall, this study underscores the vulnerability of M. galloprovincialis to cumulative stressors and highlights the importance of employing a multi-biomarker approach to assess and mitigate the impacts of stressors on coastal ecosystems.

Personal care products: an emerging threat to the marine bivalve Ruditapes philippinarum

In the last few decades, there has been a growing interest in understanding the behavior of personal care products (PCPs) in the aquatic environment. In this regard, the aim of this study is to estimate the accumulation and effects of four PCPs within the clam Ruditapes philippinarum. The PCPs selected were triclosan, OTNE, benzophenone-3, and octocrylene. A progressive uptake was observed and maximum concentrations in tissues were reached at the end of the exposure phase, up to levels of 0.68 µg g-1, 24 µg g-1, 0.81 µg g-1, and 1.52 µg g-1 for OTNE, BP-3, OC, and TCS, respectively. After the PCP post-exposure period, the removal percentages were higher than 65%. The estimated logarithm bioconcentration factor ranged from 3.34 to 2.93, in concordance with the lipophobicity of each substance. No lethal effects were found although significant changes were observed for ethoxyresorufin O-demethylase activity, glutathione S-transferase activity, lipid peroxidation, and DNA damage.

Neurotoxicity of Benzotriazole Ultraviolet Stabilizers in Teleost Fishes: A Review

Plastic additives that maintain integrity have been extensively studied for potential toxicity to fish; however, chemicals that protect polymers from (artificial) UV degradation are less studied. Benzotriazole UV stabilizers (BUVSs) are the most widely used UV stabilizers in plastics and are often used in sunscreens, cosmetics, paint, and food packaging. BUVSs can negatively affect aquatic wildlife when released into the environment via plastic degradation. In this review, we summarize the distribution of BUVSs globally and discuss neurotoxicological endpoints measured in fish to understand how these plastic additives can affect the neurological health of teleost fishes. BUVSs have been detected in aquatic environments at concentrations ranging from 0.05 up to 99,200 ng/L. Studies show that BUVSs affect behavioral responses and acetylcholinesterase activity, indicators of neurotoxicity. Our computational analysis using transcriptome data suggests certain pathways associated with neurodegeneration are responsive to exposure to BUVSs, like "Complement Activation in Alzheimer's Disease". Based on our review, we identify some research needs for future investigations: (1) molecular studies in the central nervous system to define precise mechanisms of neurotoxicity; (2) a wider range of tests for assessing aberrant behaviors given that BUVSs can affect the activity of larval zebrafish; and (3) histopathology of the nervous system to accompany biochemical analyses. These data are expected to enhance understanding of the neurotoxicity potential of benzotriazoles and other plastic additives.

Multi-biomarker approach for the (eco)toxicity of UV-filter environmental pollution on the Mediterranean mussel Mytilus galloprovincialis in a multiple stressor context. The case of 4-MBC under salinity shifts

Marine-coastal ecosystems are rapidly transforming because of climate change (CC). At the same time, the impacts of emerging organic contaminants (i.e., organic UV-filters) on these ecosystems are intensifying. In the Mediterranean, the consequences of these disturbances are occurring at a fast pace making this area a potential sentinel site to be investigated. While singular effects of organic UV-filters or CC-related factors on marine biota have been relatively described, their combined impact is still largely unknown. Thus, the objective of this study was to assess the long-term responses of the Mediterranean mussel Mytilus galloprovincialis towards anticipated salinity changes (decreases-S20 or increases-S40) when exposed to environmentally relevant concentrations of the UV-filter 4-methylbenzylidene camphor (4-MBC). An integrated multi-biomarker approach was applied, featuring general and oxidative stress, antioxidant and biotransformation enzyme capacity, energy metabolism, genotoxicity, and neurotoxicity biomarkers. Results showed that both projected salinities, considered separately, exerted non-negligible impacts on mussels' health status, with greater biological impairments found at S 40. Combining both stressors resulted in an evident increase in mussels' susceptibility to the UV-filter, which exacerbated the toxicity of 4-MBC. The dominant influence of salinity in the climate change-contaminant interaction played a crucial role in this outcome. The most severe scenario occurred when S 20 was combined with 4-MBC. In this situation, mussels exhibited a decrease in filtration rate, metabolic capacity and deployment of energy reserves increased, with an upregulation of biotransformation and inhibition of antioxidant enzyme activities. This exposure also led to the observation of cellular and DNA damage, as well as an increase in AChE activity. Furthermore, salinity-dependent bioaccumulation patterns were evaluated revealing that the lowest values in contaminated mussels are found at S 20. Overall, the present findings provide evidence that projected CC/pollutant scenarios may represent high risks for mussels' populations, with global relevant implications for the ecosystem level.

Occurrence and ecological risk assessment of organic UV filters in coastal waters of the Iberian Peninsula

This study aimed to assess the presence of 21 UVFs and metabolites in coastal regions of the Iberian Peninsula, to evaluate their environmental risk, and identify possible influential factors affecting their measured concentrations. Sampling was carried out in spring and summer to assess possible seasonal variations. UVFs were detected in 43 of the 46 sampling sites. Only 5 were found above LOD: BP4, OC, BP3 and metabolites BP1 and BP8. Samples collected in Mar Menor had the greatest variety of compounds per sample and the highest cumulative concentrations. The risk was characterized using Risk Quotients (RQ). BP1 showed a Low environmental Risk in 2 sites while for OC the RQ indicated a Moderate Risk in 22 points. The variables that contribute most to the variation are population density, sampling season, whether it was an open bay or not, and level of urbanization. The presence of WWTPs had a lower influence.

Effects of Commercial Sunscreens on Survival, Reproduction and Embryonic Development of the Aquatic Snail Biomphalaria glabrata (SAY, 1818)

Over the past few years, there has been a significant increase in the use of sunscreens. Consequently, the occurrence in aquatic environments of ultraviolet filters has also increased. The present study aims to evaluate the toxicity of two commercial sunscreens to the aquatic snail Biomphalaria glabrata. Acute assays were performed with adult snails exposed to solutions of the two products in synthetic soft water. Reproduction and development assays were carried out, involving individual adult and egg masses exposure to assess fertility and embryonic development. Sunscreen A showed a LC₅₀-96 h of 6.8 g/L and reduction in number of eggs and egg masses per individual in the concentration of 0.3 g/L. Sunscreen B presented higher malformation rates in 0.4 g/L with 63% of malformed embryos. Results indicate that the formulation used in sunscreens is an important factor in aquatic toxicity and needs to be evaluated before the final product is commercialized.

Comparative toxicogenomics of benzotriazole ultraviolet stabilizers at environmental concentrations in Asian clam (Corbicula fluminea): Insight into molecular networks and behavior

Benzotriazole ultraviolet stabilizers (BUVSs) are widespread emerging pollutants, which can pose exposure risks to benthic organisms. However, the toxicity and mechanisms of BUVSs congeners in benthic clams are far from elucidated. In this study, Asian clams (Corbicula fluminea) were exposed to one of UV-234, UV-326, UV-329, or UV-P at environmentally relevant levels (0.1, 1, and 10 μg/L) for 21 days. Filtration rate (FR) was increased in clams exposed to all BUVSs and there were notable histopathologic changes, including irregular digestive lumen, lipid droplet vacuolation, and degraded epithelial cells. To determine the molecular underpinnings following BUVSs exposure, the transcriptome responses in digestive glands were compared. Differentially expressed genes shared among BUVSs treatments were associated with focal adhesion, TNF-α/NF-κB proinflammatory pathways, and apoptosis. Following this, biochemical analysis of biomarkers related to apoptosis were conducted to further validate response. Exposure to BUVSs inhibited anti-oxidant enzyme activity and induced oxidative stress. Heat shock proteins were also triggered with exposure, and there was an induction of caspase-3 and caspase-9 activity. Molecular responses were not identical in the digestive gland of C. fluminea when comparing responses to BUVSs; nevertheless conserved mechanism (impairment of the oxidative defense system, immune system disruption, and induction of apoptosis) among BUVSs congeners was noted. This study provides novel insight into the toxicity and hazards of BUVSs in benthic organisms.

Comparative transcriptome analysis reveals immunotoxicology induced by three organic UV filters in Manila clam (Ruditapes philippinarum)

Benzophenone-3 (BP-3), 4-methyl-benzylidene camphor (4-MBC) and 2-ethyl-hexyl-4-trimethoxycinnamate (EHMC) are commonly used organic ultraviolet (UV) filters and are frequently detected in water environments. In the present study, we studied the potential adverse impacts of UV filter exposures in Ruditapes philippinarum by investigating transcriptomic profiles and non-specific immune enzyme activities. Transcriptome analysis showed that more genes were differentially regulated in EHMC-treated group, and down-regulated genes (2009) were significantly more than up-regulated ones (410) at day 7. Function annotation revealed that pathways "immune system", "cell growth and death" and "infectious diseases" were significantly enriched. Generally, combined qPCR and biochemical analyses demonstrated that short-term exposure to low dose of UV filters could activate immune responses, whereas the immune system would be restrained after prolonged exposure. Taken together, the present study firstly demonstrated the immunotoxicology induced by BP-3, 4-MBC and EHMC on R. philippinarum, indicating their potential threats to the survival of marine bivalves.

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.

Soil degradation kinetics of oxybenzone (Benzophenone-3) and toxicopathological assessment in the earthworm, Eisenia fetida

A preponderance of recent evidence indicates that oxybenzone and other personal-care product chemicals threaten the biota inhabiting various ecological niches. What is understudied is the ecotoxicological impact of oxybenzone, a UV filter in sunscreens and anti-aging products, to terrestrial/soil organisms that are keystone species in these habitats. In the present study, acute exposure (14-day) to oxybenzone resulted in earthworm mortality (LC₅₀ of 364 mg/kg) and growth rate inhibition. Environmentally relevant concentration of oxybenzone (3.64, 7.28 and 36.4 mg/kg) at exposures of 7-day, 14-day, 28-day induced oxidative stress and neurotoxicity followed by perturbations in reproduction processes and changes in vital organs. Decreased levels of superoxide dismutase (SOD) and catalase (CAT) activity were statistically lower than controls (p < 0.05) on day 14 for all three concentrations, while glutathione-s-transferase (GST) activity was significantly elevated from controls on days 7 and 14. On day 28, SOD and CAT activities were either not significantly different from the control or were higher, demonstrating a temporal multiphasic response of anti-oxidant enzymes. GST activity on day 28 was significantly reduced compared to controls. Acetylcholinesterase levels across the three-time points exhibited a complicated behaviour, with every exposure concentration being significantly different from the control. Chronic exposure negatively influences earthworm health status with elevated biomarker values analysed using IBRv2 index. This, in turn, impacted higher levels of hierarchical organization, significantly impairing reproduction and organismal homeostasis at the histological level and manifesting as decreasing cocoon formation and successful hatching events. Thus, the overall findings demonstrate that oxybenzone is toxic to Eisenia fetida at low-level, long-term exposure. Based on the concentration verification analysis and application of the EPA PestDF tool, oxybenzone undergoes single first-order kinetics degradation in OECD soil with DT50 and DT90 as 8.7-28.9 days, respectively.

Ecotoxicological effects of the UV-filter 4-MBC on sperms and adults of the mussel Mytilus galloprovincialis

Present in an increasing number of products, UV-filters are continuously discharged into aquatic environments. Despite potential risks for inhabiting organisms are recognized, the effects of UV-filter 4-methylbenzylidenecamphor (4-MBC) on marine invertebrates are poorly investigated. By combining in vitro/in vivo exposures through a multi-biomarker approach on sperms and adults, the present study evaluated how 4-MBC affect the mussel species Mytilus galloprovincialis, providing ecologically relevant information on organisms' responses. From the obtained results, considering mortality as endpoint, sperms revealed a greater sensitivity (EC₅₀:347 μg/L) than adults (EC₅₀: not calculable). From an ecotoxicological perspective, this resulted in a derived threshold concentration (LOEC) of 100 μg/L and 72 μg/L, respectively. Effects at the cell/molecular level were provided by general redox-status imbalance and oxidative stress. Sperms showed functional and structural impairments, hyperactivation and DNA damage, while adults showed physiological, metabolic/energetic dysfunctions, DNA damage and activation of oxidative and biotransformation enzymes. High 4-MBC bioaccumulation was also observed in exposed mussels (BCFs:14.0-32.0 L/kg). These findings suggest that 4-MBC may impair fitness and survival of the broadcast spawning mussel M. galloprovincialis, affecting reproduction success and population growth.

Beach showers as sources of contamination for sunscreen pollution in marine protected areas and areas of intensive beach tourism in Hawaii, USA

In 2019, sands in nearby runoff streams from public beach showers were sampled on three islands in the State of Hawaii and tested for over 18 different petrochemical UV filters. Beach sands that are directly in the plume discharge of beach showers on three of the islands of Hawaii (Maui, Oahu, Hawai'i) were found to be contaminated with a wide array of petrochemical-based UV-filters that are found in sunscreens. Sands from beach showers across all three islands had a mean concentration of 5619 ng/g of oxybenzone with the highest concentration of 34,518 ng/g of oxybenzone at a beach shower in the Waikiki area of Honolulu. Octocrylene was detected at a majority of the beach shower locations, with a mean concentration of 296.3 ng/g across 13 sampling sites with the highest concentration of 1075 ng/g at the beach shower in Waikiki. Avobenzone, octinoxate, 4-methylbenzylidene camphor and benzophenone-2 were detected, as well as breakdown products of oxybenzone, including benzophenone-1, 2,2'-dihydroxy-4-methoxybenzophenone, and 4-hydroxybenzophenone. Dioxybenzone (DHMB) presented the highest concentration in water (75.4 ng/mL), whereas octocrylene was detected in all water samples. Some of these same target analytes were detected in water samples on coral reefs that are adjacent to the beach showers. Risk assessments for both sand and water samples at a majority of the sampling sites had a Risk Quotient > 1, indicating that these chemicals could pose a serious threat to beach zones and coral reef habitats. There are almost a dozen mitigation options that could be employed to quickly reduce contaminant loads associated with discharges from these beach showers, like those currently being employed (post-study sampling and analysis) in the State of Hawaii, including banning the use of sunscreens using petrochemical-based UV filters or educating tourists before they arrive on the beach.

Enhanced Toxicity of Bisphenols Together with UV Filters in Water: Identification of Synergy and Antagonism in Three-Component Mixtures

Contaminants of emerging concern (CEC) localize in the biome in variable combinations of complex mixtures that are often environmentally persistent, bioaccumulate and biomagnify, prompting a need for extensive monitoring. Many cosmetics include UV filters that are listed as CECs, such as benzophenone derivatives (oxybenzone, OXYB), cinnamates (2-ethylhexyl 4-methoxycinnamate, EMC) and camphor derivatives (4-methylbenzylidene-camphor, 4MBC). Furthermore, in numerous water sources, these UV filters have been detected together with Bisphenols (BPs), which are commonly used in plastics and can be physiologically detrimental. We utilized bioluminescent bacteria (Microtox assay) to monitor these CEC mixtures at environmentally relevant doses, and performed the first systematic study involving three sunscreen components (OXYB, 4MBC and EMC) and three BPs (BPA, BPS or BPF). Moreover, a breast cell line and cell viability assay were employed to determine the possible effect of these mixtures on human cells. Toxicity modeling, with concentration addition (CA) and independent action (IA) approaches, was performed, followed by data interpretation using Model Deviation Ratio (MDR) evaluation. The results show that UV filter sunscreen constituents and BPs interact at environmentally relevant concentrations. Of notable interest, mixtures containing any pair of three BPs (e.g., BPA + BPS, BPA + BPF and BPS + BPF), together with one sunscreen component (OXYB, 4MBC or EMC), showed strong synergy or overadditive effects. On the other hand, mixtures containing two UV filters (any pair of OXYB, 4MBC and EMC) and one BP (BPA, BPS or BPF) had a strong propensity towards concentration dependent underestimation. The three-component mixtures of UV filters (4MBC, EMC and OXYB) acted in an antagonistic manner toward each other, which was confirmed using a human cell line model. This study is one of the most comprehensive involving sunscreen constituents and BPs in complex mixtures, and provides new insights into potentially important interactions between these compounds.

Review of the environmental fate and effects of two UV filter substances used in cosmetic products

Sunscreens containing UV filters, such as octocrylene (OCR) and butyl-methoxydibenzoylmethane (BMDBM), have been increasingly used to protect human skin against UV radiation. Both substances have been detected in monitoring studies in the freshwater and marine environment, and there has been concern about potential effects on aquatic organisms. In the present work, the environmental fate and occurrence, bioaccumulation and ecotoxicity including endocrine effects of OCR and BMDBM are reviewed focusing on the aquatic environment. The two UV filters have low water solubilities and a high sorption potential. The available data indicate that OCR is poorly biodegradable. BMDBM lacks anaerobic and inherent biodegradability. However, it was biodegraded to variable degrees in simulation studies. Measured concentrations in the freshwater and marine environment were found to vary considerably between sites, depending on the extent of recreational activities or wastewater discharges. While the bioconcentration factor of OCR in fish is below the threshold value for bioaccumulation according to EU REACH, the available data for BMDBM do not allow a definitive conclusion on its bioaccumulation potential. Analysis of the aquatic toxicity data showed that data quality was often limited, e.g. in the case of effect concentrations substantially exceeding maximum achievable dissolved concentrations. Up to their limit of water solubility, OCR and BMDBM showed no toxicity to microorganisms, algae, and corals, and no acute toxicity to daphnids and fish. In chronic daphnid tests, OCR was highly toxic, whereas BMDBM lacked toxicity. Reliable water-sediment toxicity tests are required to further evaluate possible effects on benthic invertebrates. The available data do not provide evidence for endocrine effects of the two UV filters on fish. In order to assess potential environmental risks caused by OCR and BMDBM, a validated exposure model for estimating direct emission of UV filters into the aquatic environment and data from systematic, longer-term monitoring studies are needed.

Do bio-insecticides affect only insect species? Behavior, regeneration, and sexual reproduction of a non-target freshwater planarian

Bio-insecticides have been increasingly used worldwide as ecofriendly alternatives to pesticides, but data on their effects in non-target freshwater organisms is still scarce and limited to insects. The aim of this study was to determine the lethal and sub-lethal effects of the bio-insecticides Bac Control (based on Bacillus thuringiensis kurstaki-Btk) and Boveril (based on Beauveria bassiana-Bb) on regeneration, behavioral, and reproductive endpoints of the freshwater planarian Girardia tigrina. The estimated LC_50-48h were > 800 mg a.i./L for Btk and 60.74 mg a.i./L for Bb. In addition, exposure to Btk significantly decreased locomotion and feeding activities of planarians (lowest observed effect concentration (LOEC) of 12.5 mg a.i./L Btk) and fecundity rate (LOEC = 3.12 mg a.i./L Btk), whereas exposure to Bb significantly delayed regeneration (LOEC = 0.75 mg a.i./L Bb) and decreased fecundity rate (1.5 mg a.i./L Bb) of planarians. Thus, both bio-insecticides induced deleterious sub-lethal effects on a non-insect freshwater invertebrate species. However, only Bb-based formulation affected the survival, fecundity rate, and regeneration at concentrations below the maximum predicted environmental concentration (PEC = 247 mg/L). Thus, care should be taken when using such formulations as alternatives to chemical insecticides near aquatic ecosystems.

Developmental toxicity assessment of 4-MBC in Danio rerio embryo-larval stages

Enormous production of cosmetic products and its indiscriminate use tends to discharge into the aquatic environment and might threaten non-target organisms inhabiting aquatic ecosystems. In the present study, developmental toxicity of 4-methylbenzylidene camphor (4-MBC), a widely used organic UV filter in personal care products has been evaluated using zebrafish embryo-larval stages. Waterborne exposure induced developmental toxicity and deduced 2.71 mg/L as 96 h LC₅₀ whereas embryos exposed to sub-lethal concentrations (50 and 500 μg/L) caused a significant delay in hatching rate, heart rate, reduced larval length, and restricted hatchlings motility besides the axial curvature. Chronic exposure to 10 dpf resulted in significant decrease in SOD activity at 500 μg/L with no changes in CAT level besides a significant increase in GST enzyme at 5 μg/L concentration in 5 dpf sampled larvae. However, all the three enzymes were significantly elevated in 10 dpf larvae indicating differential oxidative stress during the stages of development. Similar trend is noticed for acetylcholine esterase enzyme activity. A concentration dependent increase in malondialdehyde content was noted in larvae sampled at 5 and 10 dpf. In addition, multixenobiotic resistance (MXR) activity inhibition, and elevated oxidative tissue damage were noticed at 5 dpf with no significant changes in 10 dpf larvae. Furthermore, immunoblot analysis confirms 4-MBC induced apoptosis in zebrafish larvae with promoted cleaved Caspase-3, Bax and inhibited Bcl-2 proteins expression. Subsequently, docking studies revealed the binding potential of 4-MBC to zebrafish Abcb4 and CYP450 8A1 proteins with the binding energy of -8.1 and -8.5 kcal/mol representing target proteins interaction and toxicity potentiation. Our results showed that 4-MBC exposure triggers oxidative stress at sub-lethal concentrations leading to apoptosis, deformities and locomotion perturbations in developing zebrafish.This is first of its kind in systematically demonstrating developmental toxicity of 4-MBC and the information shall be used for aquatic toxicity risk assessment.

Elevated temperature alleviates benzophenone-3 toxicity in Daphnia magna

Water temperature rises due to thermal discharge and global warming and the potential resulting impacts on the ecotoxicity of emerging chemicals are a growing concern. Benzophenone-3 (BP-3) is an ultraviolet filter added to personal care and plastic products, which is detected at highest concentrations during the hot summer season. This study aimed to investigate the effect of elevated temperature on acute (48 h) and chronic (21 d) BP-3 toxicity in Daphnia magna. Neonates (<24 h) acclimated at 28 °C showed much lower acute toxicity (EC₅₀ = 3.91 and 2.69 mg L^-1 at 20 and 28 °C, respectively) than those acclimated at 20 °C (EC₅₀ = 2.96 and 2.04 mg L^-1 at 20 and 28 °C, respectively). The body length, embryonic development, and the number of offspring in D. magna offspring exposed to BP-3 for 21 d were significantly decreased after exposure to 0.8 mg L^-1 BP-3 at 20 °C. However, these adverse effects of BP-3 in D. magna were significantly ameliorated at 28 °C. Under these conditions, stress response genes such as Hb (hemoglobin), Hsp70 (heat shock protein), Cyp4 (cytochrome P450), and GST (glutathione-S-transferase) were significantly upregulated. These findings suggest that elevated temperature activated stress responses in D. magna, leading to enhanced protection against BP-3 toxicity. This study will contribute to a better understanding of the ecotoxicological impacts of toxic chemicals on aquatic organisms at elevated temperature.

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.

Effects of exposure to the UV-filter 4-MBC during Solea senegalensis metamorphosis

Many personal care products integrate UV-filters, such as 4-methylbenzylidene camphor (4-MBC), a compound frequently detected in aquatic habitats, including coastal areas. However, the potential effects of 4-MBC to saltwater species have been poorly studied. Therefore, the main objective of this work is to study the effects of 4-MBC exposure on Solea senegalensis during metamorphosis, a sensitive life stage of this flatfish. To achieve this, fish were exposed to 4-MBC (0.2-2.0 mg L^-1) for 48 h at the beginning of metamorphosis (13 days after hatching, dah). After this period, the fish were transferred to a clean medium. They were fed and maintained until more than 80% of individuals in the control group completed the metamorphosis (24 dah). Mortality, malformations, and metamorphic progression were studied daily. Growth, behavior, and biochemical markers of neurotransmission (acetylcholinesterase, AChE), oxidative stress (catalase, CAT; lipid peroxidation, LPO), detoxification (glutathione S-transferase, GST), and anaerobic metabolism (lactate dehydrogenase, LDH) were also determined at the end of the experiment. An acceleration of metamorphosis progression was observed during and 2 days after the 4-MBC exposure in all concentrations tested. In addition, reduced length, inhibition of CAT activity, and induction of oxidative damage were observed (lowest observed effect concentration, LOEC = 0.928 mg L^-1 4-MBC for length, CAT, and LPO). Short-term exposure to 4-MBC at the onset of metamorphosis affected S. senegalensis at several levels of organization, even after 9 days in a clean medium, including growth and metamorphic progression, suggesting possible long-term adverse effects in this species.

Toxic effects of octocrylene on zebrafish larvae and liver cell line (ZFL)

Octocrylene (OC) is a broad-spectrum ultraviolet-absorbing chemical used in sunscreen and other personal care products. Its health effects are a concern because it has been detected in water, fish, humans, and food chains. In vivo and in vitro investigations were performed in zebrafish (Danio rerio) larvae and a zebrafish liver cell line (ZFL), respectively, to understand the potential risks and molecular mechanisms of OC toxicity. The 96-h median lethal concentration (LC₅₀) of OC was determined to be 251.8 μM in larvae and 5.5 μM in ZFL cells. Quantitative real-time PCR (qRT-PCR) showed that OC induced the expression of genes for CYPs (CYP1A, CYP3A65), estrogen receptors (ERα, ERβ1, GPER), vitellogenin (VTG1), and sex determination (BRCA2, CYP19A, DMRT1, SOX9A), both in vitro and in vivo. A whole-transcriptome sequencing method was used to evaluate the gene expression profile of larvae exposed to OC. OC was found to mediate the biosynthesis of estrogens (such as estriol) and affect the antioxidant pathway (glutathione transferases and peroxisome). These findings clarify the toxic effects and molecular mechanisms of OC and support banning its use in cosmetics.

A Systematic Review on Occurrence and Ecotoxicity of Organic UV Filters in Aquatic Organisms

The growing production of cosmetic products such as organic UV filters (OUVFs) in recent years has raised concern regarding their safety to human and environmental health. The inability of wastewater treatment plants in removing these chemical entities and their high octanol-water partition coefficient values tend to result in the persistence of OUVFs in several environmental matrices, leading these to be categorized as "emerging environmental contaminants" because of their unknown risk. Besides aquatic ecosystem contamination, the application of sludge disposal equally threatens terrestrial biota. Besides, the available reviews focusing on levels of OUVFs in aqueous systems (freshwater and marine), instrumental analysis from various samples, and specific toxicity effects, compiled information on the ecotoxicity of OUVFs is currently lacking. Hence, the present manuscript systematically reviews the ecotoxicity of OUVFs in freshwater and marine organisms occupying lower to higher trophic levels, including the underlying mechanisms of action and current knowledge gaps. The available scientific evidence suggests that OUVFs are a prime candidate for environmental concern due to their potential toxic effects. To the best of our knowledge, this is the first document detailing the toxicological effects of OUVFs in aquatic organisms.

Comparative acute toxicity of benzophenone derivatives and bisphenol analogues in the Asian clam Corbicula fluminea

Among UV-filters, benzophenones are one of the most abundantly used and detected groups in the environment. Bisphenols are also one of the most widely used chemicals in plastics, but their demonstrated deleterious effects on several organisms and humans have led to the production of alternative analogues. However, few comparative studies on the ecotoxicological effects of these derivatives or analogues have been carried out. The present study aimed to investigate the effects of two benzophenones (BP-3 and BP-4) and two bisphenols (BPA and BPS) in a short-term exposure of the freshwater endobenthic bivalve Corbicula fluminea. Clams were exposed for 96 h to several concentrations of the four pollutants: BP-3 (0.63; 1.25; 2.5; 5 mg l^-1), BP-4 (4.75; 9.5; 19; 38 mg l^-1), BPA (3.75; 7.5; 15; 30 mg l^-1), and BPS (2.5; 5; 10; 20 mg l^-1). The comparative acute toxicity of these pollutants was evaluated by the analysis of the post-exposure filtering capacity of clams, lipid peroxidation (LP) levels and the activity of the antioxidant enzymes catalase (CAT) and glutathione reductase (GR). After the exposure period, except for BP-4, the chemicals tested seemed to be detected by clams and provoked valve closure, decreasing filter-feeding in a concentration-dependent manner. Furthermore, C. fluminea exposed to the highest concentrations of BP-3, BP-4 and BPA showed a significant increase in LP, CAT and GR activities with respect to their controls. BP-3 and BPA were the most toxic compounds showing significant differences in all the parameters analysed at the highest concentrations assayed. However, clams exposed to BPS showed only significant alterations in filtration parameters and in GR activity, in the two highest concentrations tested, indicating that this compound was the least toxic to clams. Obtained results highlight the importance of investigating the effects that emerging pollutants have on aquatic organisms.

A systematic review and ecological risk assessment for organic ultraviolet filters in aquatic environments

Organic ultraviolet filters (OUVFs) are used in a wide range of manufactured products including personal care (e.g. sunscreens) and plastic items. This review summarizes the available data regarding the toxic effects of OUVFs on marine and freshwater organisms and generates the predicted no-effect concentration (PNEC) values necessary for assessing ecological risk. Through a systematic search of the literature, 89 studies were identified and ecotoxicological data extracted. Collectively, these studies described toxicity testing with 39 OUVF from 10 structural classes, with derivatives of benzophenones (49%) and camphors (16%) most studied. There was a bias towards selecting freshwater species (61%), and evaluating single OUVF effects (87%) rather than OUVF mixtures. Short-term (acute) experimentation (58%) was marginally more common than long-term (chronic) testing (42%). Reproductive, developmental, genetic, and neurological toxicity were the most commonly identified effects in aquatic organism, and were associated with molecular interactions with steroid receptors, DNA, or the production of reactive oxygen species. Species sensitivity distribution and/or assessment factors were used to calculate PNECs for 22 OUVFs and the risk quotients for 12 OUVFs. When using maximum concentrations, high risk was observed for six OUVFs in marine environments (4-methylbenzylidene-camphor, octocrylene, padimate-O, benzophenone-1, and oxybenzone, ethylhexyl-4-methoxycinnamate), and for four OUVFs in freshwater environments (ethylhexyl-4-methoxycinnamate, octocrylene, avobenzone and oxybenzone). When using median concentrations, a risk to marine environments was observed for oxybenzone. The results of this review underline that there is limited knowledge of the pathological effects of OUVFs and their metabolites in aquatic environments, and this inhibits the development of informed water-quality guidelines.

Toxicological responses of Carassius auratus induced by benzophenone-3 exposure and the association with alteration of gut microbiota

Gut microbiota plays a fundamental role in host's physiology. However, the effect of organic UV filters, an emerging contaminant on gut microbiota is poorly understood. Here, fish (Carassius auratus) were exposed to 2, 20 and 200 μg/L of benzophenone-3 (BP3) for 28 days to explore the toxicological effects and its association with the changes in the gut microbiota. The BP3 accumulation is time and dose dependent in the liver and intestine. Under BP3 subchronic exposure, fish's body and intestinal weights, reactive oxygen species (ROS), immunoglobulin M (IgM) and vitellogenin (VTG) levels, as well as 7-benzyloxy-4-trifluoromethylcoumarin-O-debenzyloxylase (BFCOD) activities, were decreased. BP3 exposure has increased the abundance of Bacteroidetes phylum and Mycobacterium genus. Bioinformatic analysis revealed that the levels of ROS, IgM, estrogen receptor and VTG, activities of lysozyme, BFCOD and 7-ethoxyresorufin-O-deethylase were significantly correlated with the relative abundance of intestinal microbial genus (p < 0.05). These results highlight for the first time the association between the effects of organic UV filters on the antioxidant, immune, endocrine, and metabolic systems of the fish and changes in the gut microbiota, which extend knowledge of the role of gut microbiota in ecotoxicology.

Strategies of cellular energy allocation to cope with paraquat-induced oxidative stress: Chironomids vs Planarians and the importance of using different species

Paraquat (PQ) is still used in several countries worldwide as an herbicide for weed control in agricultural production, ponds, reservoirs and irrigation canals. Thus, PQ is frequently found in surface water systems and is potentially toxic to aquatic organisms, since it can cause mitochondrial dysfunction altering in the redox state of cells. This study aimed to investigate the chronic effects of PQ to Chironomus riparius and Girardia tigrina, and compare their physiological strategies to cope with environmental stress. The mean emergence time was the most sensitive endpoint for Chironomids, with the lowest observed effect concentrations (LOEC) being 0.02 for males and 0.1 mg PQ L^-1 for females. Moreover, PQ reduced the body weight of male and female imagoes, with LOECs of 0.5 and 2.5 mg PQ L^-1, respectively. Paraquat also decreased the respiration rate (LOEC = 2.5 mg PQ L^-1) and total glutathione (tGSH) content (LOEC = 0.5 mg PQ L^-1). Thus, the aerobic production of energy was not affected and allowed chironomids to cope with oxidative stress induced by PQ, but with consequent physiological costs in terms of development rates and weight of adults. In planarians, PQ decreased the locomotion and feeding activity, and delayed photoreceptor regeneration (LOECs = 2.5 mg PQ L^-1 for all endpoints). Despite increased aerobic energy production (LOEC = 0.5 mg PQ L^-1), planarians were not able to cope with oxidative stress induced by the highest PQ concentrations, since lipid peroxidation levels were significantly increased (LOEC = 2.5 mg PQ L^-1) concomitantly with a significant decrease of tGSH (LOEC = 2.5 mg PQ L^-1). These results showed that planarians were unable to cope with oxidative stress induced by PQ with consequent impairments of behavior and regeneration despite an increased aerobic energy production.

Toxic effects and transcriptome analyses of zebrafish (Danio rerio) larvae exposed to benzophenones

Sunscreen chemicals, such as benzophenones (BPs), are common environmental contaminants that are posing a growing health concern due to their increasing presence in water, fish, and human systems. Benzoresorcinol (BP1), oxybenzone (BP3), and dioxybenzone (BP8) are the most commonly used BPs for their ability to protect from sunburn by absorbing a broad spectrum of ultraviolet radiation. In this study, zebrafish larvae were used as an in vivo model to investigate the potential risks and molecular mechanisms of the toxic effects of BPs. The effects of these BPs on the gene expression in the aryl hydrocarbon receptor pathway, estrogen receptor pathway, and sex differentiation were detected using quantitative real-time PCR. All BPs were found to function as agonists of the estrogen receptors α and β1, indicating that these BPs likely undergo similar molecular metabolism in vivo, whereby they can activate cytochrome P450 genes and promote the expression of CYP19A and DMRT1. Furthermore, the gene expression profile of larvae after BP3 exposure was evaluated using a whole transcriptome sequencing approach. BP3 affected estradiol biosynthesis and sex differentiation. It also regulated gonadotropin-releasing hormone, thus interfering with the endocrine system. As a xenobiotic toxicant, BP3 upregulated the expression of cytochrome P450 genes (CYP1A and CYP3A65) and glutathione metabolism-related genes (GSTA, GSTM, and GSTP). It also interfered with the nervous system by regulating the calcium signaling pathway. These findings will be useful for understanding the toxicity mechanisms and metabolism of BPs in aquatic organisms and promote the regulation of these chemicals in the environment.

Impacts of UV Filters in Mytilus galloprovincialis: Preliminary Data on the Acute Effects Induced by Environmentally Relevant Concentrations

Ultraviolet (UV) filters are present in a broad range of personal hygiene products, which may be transported via aquatic environments and domestic wastewaters due to inefficient treating station sewage removal and direct human contact. The aim of the present study was to evaluate the potential effects of a UV filter, in particular benzophenone-3 (BP3) (also known as oxybenzone) on the mussel species Mytilus galloprovincialis. Mussels were exposed to this organic substance for 96 h in environmentally relevant concentrations (10, 100, and 1000 ng/L). After exposure, biomarkers related with the mussels’ metabolism and oxidative stress were evaluated. The results revealed significantly higher activity of electron transport system and energy reserves (glycogen and protein (PROT)) at the intermediate concentration of 100 ng/L, suggesting that at lower concentrations mussels’ metabolism was not activated due to low stress. Conversely, at the highest concentration (1000 ng/L), mussels were no longer able to continue to increase their metabolic activity. Higher metabolic capacity was accompanied by increased PROT content associated with increased enzyme production to activate their antioxidant system. Nevertheless, at the highest concentration, cellular damage occurred as a consequence of ineffective activation of antioxidant and biotransformation enzymes. The results of the present study address uncertainties that are fundamental to the environmental risk assessment and management of these economically important near-shore bivalves and other marine species. Although an acute exposure was performed, alterations observed indicate the negative impacts of BP3 towards marine bivalves, which could be enhanced after longer exposure periods or if mussels are simultaneously exposed to other stressors (e.g., other pollutants or climate change related factors). The present study may thus contribute to the definition of fundamental knowledge for the establishment of appropriate regulatory guidelines and practices that ensure the preservation and sustainability of biological resources, allowing for prediction and mitigation of the impacts from these compounds.

Comparative toxicity of UV-filter Octyl methoxycinnamate and its photoproducts on zebrafish development

In the present study, we explored the adverse effects of Octyl methoxycinnamate (OMC), and its photoproducts, namely 2-ethylhexanol (2-EH) and 4-methoxybenzaldehyde (4-MBA) on the developmental stages of zebrafish using various biomarkers such as developmental toxicity, oxidative stress, antioxidant response, neurotoxicity and histopathological changes. The 96 h effective concentrations (EC₅₀) of OMC, 2-EH and 4-MBA were found to be 64.0, 34.0 and 3.5 µg/mL, respectively in the embryo toxicity test. Embryos exposed to the EC₅₀ of OMC, 2-EH and 4-MBA showed time-dependent increases in the malformation, heart rate and hatching delay. The lipid peroxidation (LPO) level was significantly (p < 0.05) increased and both induction and inhibition of SOD, CAT, GPx and GST activities were observed in the zebrafish embryos exposed to OMC, 2-EH and 4-MBA. GSH activity was significantly (p < 0.05) decreased in the highest exposure groups, when compared with the control. AChE activity was increased in lower concentrations of OMC, 2-EH and 4-MBA exposed embryos whereas, the activity was found to be decreased in highest concentration. Moreover, the histopathological studies showed severe damage to the muscle fibers and yolk sac regions of the larvae with 4-MBA treatment. The photoproduct 4-MBA has the highest toxic effect, followed by 2-EH and OMC. Our results provide useful insights into the impacts of OMC and its photoproducts on zebrafish development.

Effects of the organic UV-filter, 3-(4-methylbenzylidene) camphor, on benthic invertebrates and ecosystem function in artificial streams

In the last decades, the use of organic ultraviolet-filters (UV-filters) has increased worldwide, and these compounds are now considered emerging contaminants of many freshwater ecosystems. The present study aimed to assess the effects of 3-(4-methylbenzylidene) camphor (4-MBC) on a freshwater invertebrate community and on associated ecological functions. For that, artificial streams were used, and a natural invertebrate benthic community was exposed to sediments contaminated with two concentrations of 4-MBC. Effects were evaluated regarding macroinvertebrate abundance and community structure, as well as leaf decomposition and primary production. Results showed that the macroinvertebrate community parameters and leaf decomposition rates were not affected by 4-MBC exposure. On the other hand, primary production was strongly reduced. This study highlights the importance of higher tier ecotoxicity experiments for the assessment of the effects of low concentrations of organic UV-filters on freshwater invertebrate community structure and ecosystem functioning.

Evaluation of the hazard of irregularly-shaped co-polyamide microplastics on the freshwater non-biting midge Chironomus riparius through its life cycle

Plastics pollution is increasingly attracting societal and political attention. However, despite extensive research effort recently dedicated to the hazard of plastics in the environment, the data obtained are often redundant and essential knowledge gaps exist: available freshwater ecotoxicity data mostly concern Daphnia magna and are derived from acute exposure to spherical particles. In this paper, we address this gap by exploring the biological effects of irregularly-shaped co-polyamide (PA, 10-180 μm) on Chironomus riparius - a very versatile organism that during its life-stages inhabits both sediment and water column - relevant compartments for microplastics (MP) pollution. C. riparius represents an important part of the freshwater food chain and is also a standard OECD test organism. Different toxicity endpoints along the life cycle of C. riparius (28 days) were used as described in OECD 218: emergence, time to emergence, sex ratio of imagoes and the number of egg clutches per female. Chironomid larvae were exposed to 100 mg PA kg^-1 (i.e., 10,100 particles kg^-1) sediment throughout. Soluble Zn-salt (1 mg Zn L^-1) was used as a positive control and as a co-pollutant in combination with PA. We demonstrated that the tested concentrations of PA and Zn alone as well in combination showed no adverse effects for C. riparius in chronic exposures. 100 mg PA kg^-1 also did not affect the life cycle traits of the offspring of PA-exposed parent Chironomids. The data obtained will be useful for environmental risk assessment of PA when actual environmental concentrations of PA will be available.

Evaluation of the Oxidative Stress Status in Zebrafish (Danio rerio) Liver Induced by Three Typical Organic UV Filters (BP-4, PABA and PBSA)

Organic UV filters are a kind of emerging pollutants, which have been widely used in personal care products (PCPs). This study evaluated the effects of benzophenone-4 (BP-4), 4-aminobenzoic acid (PABA), and 2-phenylbenzimidazole-5-sulfonic acid (PBSA) on the selected indices of antioxidative responses in zebrafish (Danio rerio) liver. Zebrafish were exposed to two different doses (i.e., 0.5 and 5 mg L^-1) of semi-static water with three individual compounds. Liver samples were collected on 7 and 14 days to analyze biochemical indicators, including superoxide dismutase (SOD), glutathione S-transferase (GST), reduced glutathione (GSH), and malondialdehyde (MDA). Oxidative stress occurred in zebrafish liver with significantly changed indicators during the whole exposure period. Different experimental groups could induce or inhibit the activity of antioxidant enzymes with varying degrees. With a prolonged exposure time and increased exposure dose, the hepatic lipid peroxidation was also obviously observed. Moreover, the toxicity order of three organic UV filters was analyzed using the integrated biomarker response (IBR) index and the results indicate that exposure to PABA for 7 days at 0.5 mg L^-1 and PBSA for 7 days at 5 mg L^-1 induced the most severe oxidative stress in the liver of zebrafish.

Combined effects of benzophenone-3 and temperature on gene expression and enzymatic activity in the aquatic larvae Chironomus riparius

Climate change and pollution are two of the main environmental problems living organisms currently face. Temperature can modify a toxicant's effects and the organism's response to it. Global warming is expected to increase the temperature of freshwater ecosystems. In this work, we analyzed the effect of a mild temperature increase on the acute response of the aquatic larvae Chironomus riparius to the ultraviolet filter benzophenone-3 (BP3). This substance is commonly used in sunscreens and other commercial products and can reach the environment in different ways. We exposed larvae to BP3 at 18.5 or 23 °C for 8 or 24 h and analyzed the acute response at the molecular level. By quantitative real-time polymerase chain reaction (q-PCR), we studied altered messenger RNA (mRNA) levels of genes related to the endocrine system (EcR, InR and Met), detoxification mechanisms (Cyp4d2, Cyp6b7, GST d6, GST o1 and MRP-1) and stress response (Hsp22, Hsp27, Hsp70, HYOU and Gp93). Moreover, enzyme activity was evaluated, with a focus on glutathione-S-transferase (GST), phenoloxidase (PO) and acetylcholinesterase (AChE). Results showed that temperature affected the acute response of this organism by modifying the expression of EcR, Cyp6b7, GST d6, GST o1, MRP-1, Hsp22, Hsp27 and Hsp70 genes. These results suggest that even mild temperature change can affect the response of this organism to BP3 influencing short-term progress of the population. Although longer exposures are required to determine the ability of C. riparius to manage the pollutants in this novel environmental conditions, in order to know the possible mechanisms of detoxification or adaptation that may develop. This research represents a first step in the analysis of multi-stress response in this animal, and opens new possibilities in the toxicity evaluation of this organism in line with the real scenario that organisms face today.

Assessment of fipronil toxicity to the freshwater midge Chironomus riparius: Molecular, biochemical, and organismal responses

Fipronil is a phenylpyrazole insecticide that entered the market to replace organochlorides and organophosphates. Fipronil impairs the regular inhibition of nerve impulses that ultimately result in paralysis and death of insects. Because of its use as a pest control, and due to runoff events, fipronil has been detected in freshwater systems near agricultural areas, and therefore might represent a threat to non-target aquatic organisms. In this study, the toxicity of fipronil to the freshwater midge Chironomus riparius was investigated at biochemical, molecular, and whole organism (e.g. growth, emergence, and behavior) levels. At the individual level, chronic (28 days) exposure to fipronil resulted in reduced larval growth and emergence with a lowest observed effect concentration (LOEC) of 0.081 μg L^-1. Adult weight, which is directly linked to the flying performance and fecundity of midges, was also affected (LOEC = 0.040 μg L^-1). Additionally, behavioral changes such as irregular burrowing behavior of C. riparius larvae (EC₅₀ = 0.084 μg L^-1) and impairment of adult flying performance were observed. At a biochemical level, acute (48 h) exposure to fipronil increased cellular oxygen consumption (as indicated by the increase of electron transport system (ETS) activity) and decreased antioxidant and detoxification defenses (as suggested by the decrease in catalase (CAT) and glutathione S-transferase (GST) activities). Exposure to fipronil also caused alterations in the fatty acid profile of C. riparius, since high levels of stearidonic acid (SDA) were observed. A comparison between exposed and non-exposed larvae also revealed alterations in the expression of globins, cytoskeleton and motor proteins, and proteins involved in protein biosynthesis. These alterations may aid in the interpretation of potential mechanisms of action that lead to the effects observed at the organism level. Present results show that environmentally relevant concentrations of fipronil are toxic to chironomid populations which call for monitoring of phenylpyrazole insecticides and of their ecological effects in freshwaters. Present results also emphasize the importance of complementing ecotoxicological data with molecular approaches such as proteomics, for a better interpretation of the mode of action of insecticides in aquatic invertebrates.

Systemic availability of lipophilic organic UV filters through dermal sunscreen exposure

BACKGROUND

Chemical UV filters are common components in sunscreens and cosmetic products and used to protect the skin against harmful effects of sunlight like sunburn. However, the effectiveness of sunscreens in the prevention of skin cancer is in some parts still controversial. Meanwhile, questions about negative effects of the chemical UV filters on human health arise and request an effective risk assessment. Real-life exposure data in humans after application of these products are still rare. Thus, we explored whether and to what extent UV filters are absorbed through the skin into the human body.

MATERIAL AND METHODS

Plasma and urine samples from 20 healthy volunteers were collected before, during and after a real-life exposure scenario (1st application: 2 mg/cm²; 2nd and 3rd (after 2 and 4 h): 1 mg/cm² each) using a commercial sunscreen formulation for one day. These samples were analyzed for their content of the currently prominent UV filters octocrylene and avobenzone as well as 2-cyano-3,3-diphenylacrylic acid (CDAA) as the main octocrylene metabolite by using different liquid chromatography electrospray-ionization tandem mass spectrometric procedures.

RESULTS

Following dermal sunscreen exposure, avobenzone, octocrylene and CDAA reached concentrations up to 11 μg/L, 25 μg/L and 1352 μg/L in plasma. In urine detection rates of avobenzone and octocrylene were low while CDAA showed a high detection rate and reached up to 5207 μg/g creatinine. Kinetic models could be fitted for octocrylene and CDAA in plasma and CDAA in urine. Concentration peaks were reached between 10 and 16 h after first application and half-life periods were in the range of 1.5 to 2 days. The lipophilic UV filter octocrylene and its metabolite CDAA showed a much slower elimination than other more hydrophilic UV filters. Concordantly, the metabolite CDAA in particular showed a markedly increased renal excretion over the whole sampling period and indicated high internal exposure to OC.

DISCUSSION

Real-life sunscreen usage leads to considerable bioavailability of organic UV filters and their metabolites which is rarely seen for other environmental exposures. A combined monitoring of the parent compound and its metabolites is important to fully address internal exposure to the UV filter in humans. Considering the kinetic profiles a prolonged systemic release due to depot formation in skin and a potential accumulation through multi-day exposure is presumed. High in-vivo loads call for a critical toxicological assessment of the UV filters and their metabolites.

Organic ultraviolet (UV) filters in the South China sea coastal region: Environmental occurrence, toxicological effects and risk assessment

Organic ultraviolet (UV) filters are common ingredients of personal care products and occur ubiquitously in the aquatic environment; however, little is known about their distribution in and potential effects to the marine environment. This study reports the occurrence, toxicological effects and risk assessment of eleven commonly consumed UV filters in marine surface water collected from the South China Sea (SCS) coastal region. The concentrations of UV filters ranged from <MDL to 145 ng/L in the SCS, in which benzophenone-3, octocrylene and butyl methoxydibenzoylmethane were the most dominant compounds with their detection frequencies over 97%. Relatively higher levels of total UV filters were found near the highly industrialized and urbanized Pearl River Estuary (PRE) and the concentrations gradually decreased towards the SCS. In general, the environmental levels of UV filters were higher at the western marine waters in Hong Kong than the eastern marine waters. Significant negative correlations were observed between benzophenone-4 and water temperature, as well as ethylhexyl methoxycinnamate and salinity (P < 0.001; r < -0.5). Immobilization test of barnacle nauplius larvae (Balanus amphitrite) was conducted to assess the acute toxicity of organic UV filters to marine organisms. Benzophenone-8 and 4-methylbenzylidene camphor showed relatively higher toxicity with the 50% effect concentrations (EC₅₀) of 2.2 and 3.9 mg/L, respectively. A preliminary risk assessment was conducted by the results obtained from our field and laboratory studies. Results showed that the risk to cause immobilization in barnacle nauplius larvae in associated with exposure to current levels of organic UV filters in the SCS was minimal.

Applying sunscreens on earthworms: Molecular response of Eisenia fetida after direct contact with an organic UV filter

The use of organic Ultraviolet (UV) filters has increased in the last years, either in sunscreens, other cosmetics, or even food packaging. These filters may end up in soil and water since the Wastewater Treatment Plants may not successfully remove them. Among them, benzophenones are known to act as endocrine disruptors. However, most of the studies are directed towards vertebrates and aquatic invertebrates, while there is a lack of information on the molecular mechanisms affected by these compounds on soil dwelling invertebrates. Here, we study the impact of direct acute (48 h) contact of 4-hydroxybenzophenone (4-OHBP) at two sublethal concentrations (0.02 and 0.2 mg/mL) on gene expression of the earthworm Eisenia fetida. Investigated genes were involved in endocrine pathways, stress response, detoxification mechanisms, genotoxicity, energy metabolism and epigenetics. Three of them were identified for the first time in earthworms. Our results suggest that exposure to 4-OHBP affected endocrine pathways, causing an increase in the Ecdysone receptor gene (EcR) expression. Moreover, the UV filter induced changes in the CuZn superoxide dismutase gene (CuZn SOD), indicating an effect in the stress response. Finally, significant changes were detected for glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH) expression, indicating that energy metabolism is influenced by the 4-OHBP and highlighting the risks of using GAPDH as an internal reference for Real Time PCR.

Two-generational effects of Benzophenone-3 on the aquatic midge Chironomus riparius

Organic UV-filters are emergent contaminants continuously released into the aquatic ecosystems. These compounds are persistent showing potential for bioaccumulation. Partial life-cycle tests may underestimate the toxicity of UV-filters especially since these compounds have shown to act as endocrine disruptors. In the present study, the benthic aquatic insect Chironomus riparius was exposed to a gradient of Benzophenone-3 (BP3) concentrations over two generations to assess effects over a full life cycle from the first-instar larvae in the parental (P) generation (emergence, fecundity and fertility) until emergence in the subsequent generation (filial - F1). Recovery from exposure was also assessed after one generational exposure. Our results showed that concentrations of up to 8mg BP3/kg, elicited no effects regarding emergence rate and development time of C. riparius in the P generation. Our results also showed that C. riparius fecundity was not affected by BP3 exposure, but a strong dose-response relationship was observed for fertility with none of the egg ropes hatching at 8mg BP3/kg. Regarding effects observed in the F1 generation, emergence and development time were impaired by continuous exposure to BP3. Moreover, reduced emergence and changes in development time were observed in the F1 generation maintained in control/clean conditions but whose parents were exposed to BP3. Results found in this two-generational study clearly show reproductive effects of BP3 on C. riparius that would not be detected using standard tests. Full life cycle and multigenerational assays are critical to properly evaluate the population level effects of endocrine disrupting compounds such as organic UV-filters.

Amitraz toxicity to the midge Chironomus riparius: Life-history and biochemical responses

Acute and chronic toxicity of the formamidine pesticide amitraz to the midge Chironomus riparius was assessed using conventional ecotoxicological tests and biochemical approaches (biomarkers). Amitraz is mainly used as an ectoparasiticide in veterinary medicine, but also in agriculture and apiculture. However, information of amitraz toxicity to non-target invertebrates is limited. Besides the impairment of developmental and emergence rates (reduced larval growth, emergence, and delayed development time) caused by chronic exposure to amitraz, acute exposures induced alterations in the antioxidant enzymes glutathione peroxidase (GPx) and catalase (CAT), and in energetic metabolism biomarkers, lactate dehydrogenase (LDH) and electron transport system (ETS) activities. Moreover, lipid peroxidation (LPO) increased by amitraz exposure. Our results reveal potential secondary effects of amitraz to invertebrates and biomarkers that may aid in the interpretation of sub-lethal toxic responses to amitraz. These results add information concerning the potential outcomes of amitraz exposure to freshwater invertebrates underlining the importance of risk assessment studies of formamidine pesticides.

Toxicity effects of the organic UV-filter 4-Methylbenzylidene camphor in zebrafish embryos

Ultraviolet (UV) filters are widely used in personal care products and due to their lipophilicity these chemicals tend to bioaccumulate in the aquatic biota. 4-Methylbenzylidene camphor (4-MBC) is one of the most used UV-filters, and it is commonly detected in freshwater fish tissues. This substance is suspected to be an endocrine disruptor due to its interaction with Hypothalamus-Pituitary-Gonadal (HPG) and HP-Thyroid (HPT)-axis. The main objective of this study was to evaluate the effects of 4-MBC on apical endpoints, biochemical markers and on genes involved in endocrine pathways in Danio rerio. Zebrafish embryos were exposed to 4-MBC (0.083-0.77 mg/l) from 0 to 96 h post-fertilization (hpf). Hatching, heart rate and malformations were the apical endpoints assessed. Alterations on neurotransmission and oxidative stress were evaluated through acetylcholinesterase (AChE), catalase (CAT) and glutathione S-transferase (GST) enzymatic activities. Endocrine effects were analysed by the expression of genes involved in HPG and HPT-axis of embryos exposed 96 h to the EC₁₀ of 4-MBC (0.19 mg/l). Exposure to 4-MBC induced morphological abnormalities during embryonic development, including notochord curvature, delayed absorption of yolk sac and pericardial oedema. Concentration of 0.77 mg/l 4-MBC decreased embryo heart rate at 48h. At neurotransmission level, an induction of AChE at concentrations above 0.15 mg/l was observed. Malformations and decreased heart rate along with alterations observed at neurotransmission level might have compromised zebrafish larvae equilibrium. Glutathione S-transferase induction above 0.15 mg/l 4-MBC suggests activation of detoxification processes. Furthermore, observed brain aromatase gene down-regulation by 4-MBC suggests impairment of normal functioning of HPG axis in zebrafish.

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.

Bioaccumulation and Biomagnification of 2-Ethylhexyl-4-dimethylaminobenzoate in Aquatic Animals

2-Ethylhexyl-4-dimethylaminobenzoate (EHDAB) is a commonly used organic ultraviolet filter. The bioaccumulation and biomagnification of EHDAB were investigated in two aquatic animals, the larvae of midge (Chironomus riparius) and crucian carp (Carassius carassius), and the metabolic enzyme responses in fish liver were determined. EHDAB in the larvae of midge reached a steady state within 10 days of sediment exposure. The biota-sediment accumulation factors ranged from 0.10 to 0.54, and were inversely proportional to the exposure concentrations. The EHDAB-contaminated larvae were used to feed the crucian carp. Within 28 days of feeding exposure, the EHDAB levels in fish tissues gradually increased with the increase of the exposure concentration, exhibiting an apparent concentration-dependence and time-dependence. The liver and kidneys were the main organs of accumulation, and the biomagnification factors of EHDAB ranged from 8.97 to 11.0 and 6.44 to 10.8, respectively. In addition, EHDAB significantly increased the activities of cytochrome P450 (CYP) 1A, CYP3A and glutathione S-transferase in the fish liver. Our results indicate that EHDAB may pose a risk of biomagnification in an aquatic environment and influence the biological processes of exposed organisms.

Effects of UV filter 4-methylbenzylidene camphor during early development of Solea senegalensis Kaup, 1858

The inclusion of organic UV filters in personal care products (PCPs) has increased in recent years. 4-Methylbenzylidene camphor (4MBC) is one of the most used UV filters, and thus it is commonly found in aquatic ecosystems, with proved negative effects on aquatic organisms. Effects on early life stages of marine vertebrates are largely unknown. Therefore, the main goal of this work was to evaluate 4MBC effects on Senegalese sole (Solea Senegalensis Kaup, 1858) larvae at different levels of biological organization. S. senegalensis were exposed to increasing concentrations of 4MBC from egg stage until 96 h. Mortality, growth, malformations, behaviour and biochemical responses, including enzymatic biomarkers were studied. The exposure to 4MBC until 96 h post-fertilization (hpf) induced mortality and malformations in a dose-response manner. Besides, reduced growth with increasing concentrations was observed. The exposure to 4MBC also caused alterations on behaviour, including overall lower swimming time during light and dark periods. Biomarker alterations caused by 4MBC included imbalance of neurotransmission related endpoints (increased acetylcholinesterase activity) and decreased activity of enzymes related to anaerobic metabolism (lower cellular lactate dehydrogenase activity) at the lower concentrations tested. Furthermore, our results suggest that 4MBC do not induce oxidative stress in S. senegalensis larvae, since catalase and lipid peroxidation levels were not significantly altered by 4MBC. S. senegalensis revealed to be a good model species for vertebrate animal testing in the marine environment. Sub-lethal concentrations of 4MBC induced toxic effects at all organizational levels. Swimming behaviour was a sensitive endpoint and showed that exposure to 4MBC causes impairment on response to light stimulus which is possibly linked with the observed imbalances on cholinesterase activity in larvae. Conservation concerns along distribution range of S. senegalensis should consider that increasing levels of UV filters in marine environment might have impact on the ecology of the species.

Response of detoxification system genes on Chironomus riparius aquatic larvae after antibacterial agent triclosan exposures

Triclosan (TCS) is an antimicrobial agent used in a range of personal care and consumer products and is commonly detected in aquatic ecosystems. In the present study, the effects of TCS at the molecular level on the detoxification system of Chironomus riparius aquatic larvae, a test organism widely used for the assessment of aquatic toxicology, were evaluated. The obtained results show that this xenobiotic was able to induce significant changes in transcripts from different cytochrome P450s and glutathione s-transferases genes, involved in phase I and phase II of detoxification system, respectively. In contrast, TCS did not affect the glutathione S-transferase enzyme activity nor the expression pattern of multidrug resistance-associated protein 1, which belongs to phase III of detoxification system. These results provide information about the effects of TCS on the detoxification mechanism of C. riparius and offers different biomarker genes that could be useful in ecotoxicological studies, risk assessment and bioremediation.

Environmental effects of ozone depletion, UV radiation and interactions with climate change: UNEP Environmental Effects Assessment Panel, update 2017

The Environmental Effects Assessment Panel (EEAP) is one of three Panels of experts that inform the Parties to the Montreal Protocol. The EEAP focuses on the effects of UV radiation on human health, terrestrial and aquatic ecosystems, air quality, and materials, as well as on the interactive effects of UV radiation and global climate change. When considering the effects of climate change, it has become clear that processes resulting in changes in stratospheric ozone are more complex than previously held. Because of the Montreal Protocol, there are now indications of the beginnings of a recovery of stratospheric ozone, although the time required to reach levels like those before the 1960s is still uncertain, particularly as the effects of stratospheric ozone on climate change and vice versa, are not yet fully understood. Some regions will likely receive enhanced levels of UV radiation, while other areas will likely experience a reduction in UV radiation as ozone- and climate-driven changes affect the amounts of UV radiation reaching the Earth's surface. Like the other Panels, the EEAP produces detailed Quadrennial Reports every four years; the most recent was published as a series of seven papers in 2015 (Photochem. Photobiol. Sci., 2015, 14, 1-184). In the years in between, the EEAP produces less detailed and shorter Update Reports of recent and relevant scientific findings. The most recent of these was for 2016 (Photochem. Photobiol. Sci., 2017, 16, 107-145). The present 2017 Update Report assesses some of the highlights and new insights about the interactive nature of the direct and indirect effects of UV radiation, atmospheric processes, and climate change. A full 2018 Quadrennial Assessment, will be made available in 2018/2019.

Ecotoxicity of two organic UV-filters to the freshwater caddisfly Sericostoma vittatum

Organic ultraviolet filters (UV-filters) used for protection against radiation in personal care products and other materials (e.g. textiles, plastic products) are considered emerging contaminants of aquatic ecosystem. Benzophenone-3 (BP3) and 3-(4-methylbenzylidene)camphor (4-MBC) are the most commonly used organic UV-filters and have been reported in freshwater environments due to contamination through discharges from wastewater treatment plants and swimming pools or by direct contamination from recreational activities. Our aim was to evaluate the ecotoxicological effects of these UV-filters using the freshwater caddisfly Sericostoma vittatum' biochemical biomarkers and energy processing related endpoints (feeding behaviour, energy reserves and cellular metabolism). In laboratory trials, both compounds induced feeding inhibition of S. vittatum at 3.55 mg/kg of BP3 and at concentrations ≥2.57 mg/kg of 4-MBC, decreased carbohydrates content at 3.55 and 6.95 mg/kg of BP3 and 4-MBC respectively, and increased total glutathione levels at concentrations ≥1.45 and 1.35 mg/kg of BP3 and 4-MBC respectively. No significant effects were observed on endpoints associated with oxidative stress, antioxidant defences, phase II biotransformation or neurotoxicity after exposure to the two UV-filters. Our results show that environmental relevant concentrations of BP3 and 4-MBC, can negatively impact freshwater insects and demonstrate the importance of monitoring the ecological effects of organic UV-filters using non-model invertebrate species.