Simultaneous determination of the UV-filters benzyl salicylate, phenyl salicylate, octyl salicylate, homosalate, 3-(4-methylbenzylidene) camphor and 3-benzylidene camphor in human placental tissue by LC–MS/MS. Assessment of their in vitro endocrine activity

Are UV filters better together? A comparison of the toxicity of individual ultraviolet filters and off-the-shelf sunscreens to Daphnia magna

Organic ultraviolet filters (UVFs) are known to contaminate many aquatic ecosystems, with much environmental contamination attributed to the use of UVF-containing skin care products such as sunscreens during aquatic recreation. Most studies addressing the impact of sunscreen contamination have focused on the effects of UVFs under the assumption that they are the primary contaminants of concern from sunscreen pollution; however, the extent to which the toxicity of UVFs is representative of the environmental impacts of the whole sunscreen mixture is unknown. To address this knowledge gap, this study compared the mixture toxicity of five off-the-shelf sunscreen spray products containing the UVFs avobenzone, homosalate, octisalate, octocrylene and oxybenzone to the toxicity of each UVF in isolation to the freshwater invertebrate Daphnia magna. It was found that sunscreen toxicity was not proportional to their total UVF content, as the sunscreen containing the fewest UVFs was approximately equivalent to the sunscreen with the most UVFs, causing ≥90 % mortality and inhibiting all daphnid reproduction over 21 d exposures. Sunscreen toxicity was typically lower than expected when compared to the toxicity of each individual UVF within the mixture, as some sunscreens causing ≤20 % mortality contained octocrylene and/or oxybenzone at concentrations exceeding those which caused 90 % mortality during exposure to the UVF alone. Despite sunscreens causing large impairments in reproduction, growth and metabolism, poor correlations existed between the severity of most sublethal endpoints with respect to the measured UVF content of each sunscreen. Overall, these results indicate that potential antagonistic relationships between sunscreen ingredients can greatly reduce the toxicity of UVFs, creating more uncertainty regarding the level of threat that UVFs pose to the environment as a result of sunscreen contamination.

Homosalate and ERK Knockdown in the Modulation of Aurelia coerulea Metamorphosis by Regulating the PI3K Pathway and ERK Pathway

Metamorphosis control is pivotal in preventing the outbreak of jellyfish, and it is often studied using common model organisms. The widespread use of the ultraviolet blocking agent homosalate in cosmetics poses a threat to marine ecosystems. Although the impact of homosalate on marine organisms has been extensively examined, there is a notable absence of research on its effects on jellyfish metamorphosis and the underlying mechanisms, warranting further investigation. In this study, we first established a study model by using 5-methoxy-2-methylindole to induce Aurelia coerulea metamorphosis, and selected homosalate as a PI3K agonist and an ERK agonist, while we used YS-49 as a specific PI3K agonist, as well as ERK knockdown, to observe their effect on the metamorphosis of Aurelia coerulea. The results showed that an Aurelia coerulea metamorphosis model was established successfully, and the PI3K agonist homosalate, YS-49, and the knockdown of ERK molecules could significantly delay the metamorphosis development of Aurelia coerulea. We propose that activating PI3K/Akt and inhibiting the ERK pathway are involved in the delayed development of Aurelia coerulea, which provides a new strategy for the prevention and control of jellyfish blooms.

Embryonal exposure to 4-methylbenzylidene camphor induces reproduction impairment in adult zebrafish (Danio rerio)

This study investigated how early exposure to xenobiotics can lead to disease in adulthood, which is challenging for toxicologists. We employed a 'cradle to grave' approach using zebrafish (Danio rerio) embryos exposed to 4-methylbenzylidene camphor (4-MBC), a commonly used organic UV filter. Molecular docking and simulation studies confirmed the predictive toxicity and stable interaction of 4-MBC with androgen and estrogen receptors, with binding energies of -9.28 and -9.01 kcal/mol, respectively. Exposure to 4-MBC at 5, 50, and 500 μg/L concentrations resulted in significantly altered transcriptional and translational responses of ar, esr1, and vtg1 genes in embryos at 120 h post-fertilization (hpf). The exposure induced a non-monotonic dose-response pattern (NMDR), a characteristic feature of endocrine-disrupting chemicals. Additionally, a significant decrease in fertilization was observed in adults. Although fecundity was not affected in inter- and intra-breeding performances, developmental deformities were observed in F1 progenies with impaired survival at 10 days post-fertilization. The findings of this study show that embryonic exposure to 4-MBC is likely to induce reproductive and transgenerational toxicity in D. rerio and exhibit endocrine disruption in aquatic non-target organisms. This work is the first to elucidate the low-level long-term effects of 4-MBC from the embryonic stage to adulthood.

Toxicokinetics of 2-ethylhexyl salicylate (EHS) and its seven metabolites in humans after controlled single dermal exposure to EHS

The chemical UV filter 2-ethylhexyl salicylate (EHS) is used in various personal-care products. The dermal and oral metabolism of EHS have already been targeted by different studies. However, toxicokinetic data after a single dermal exposure to EHS was missing. In our study, three volunteers were dermally exposed to a commercial EHS-containing sunscreen for 9 h with an application dose of 2 mg sunscreen per cm2 body surface area. The exposure was performed indoors, and sunscreen was applied on about 75% of the total skin area. Complete urine voids were collected over 72 h and eight blood samples were drawn from each subject. Urine samples were analyzed for EHS and seven known metabolites (5OH-EHS, 4OH-EHS, 2OH-EHS, 6OH-EHS, 4oxo-EHS, 5oxo-EHS, and 5cx-EPS) by online-SPE UPLC MS/MS. The peaks of urinary elimination occurred 10-11 h after application. The elimination half-lives (Phase 1) were between 6.6 and 9.7 h. The dominant urinary biomarkers were EHS itself, followed by 5OH-EHS, 5cx-EPS, 5oxo-EHS, and 4OH-EHS. 2OH-EHS, 6OH-EHS, and 4oxo-EHS were detected only in minor amounts. An enhanced analysis of conjugation species revealed marginal amounts of unconjugated metabolites and up to 40% share of sulfate conjugates for 5OH-EHS, 5oxo-EHS, and 5cx-EPS. The results demonstrated a delayed systemic resorption of EHS via the dermal route. Despite an extensive metabolism, the parent compound occurred as main urinary parameter. The delayed dermal resorption as well as the slow elimination of EHS indicate an accumulation up to toxicological relevant doses during daily repeated dermal application to large skin areas.

New metabolites of 2-ethylhexyl salicylate in human urine after simulated real-life dermal sunscreen application

2-Ethylhexyl salicylate (EHS) is an organic UV filter which is used in sunscreen and other personal care products. The dermal uptake of EHS was studied in several dermal-exposure experiments. This paper aims to coherently assess urine samples after dermal exposure for the biomarkers EHS, 5OH-EHS, 5oxo-EHS, and 5cx-EPS as well as further biomarkers of interest, specifically 4OH-EHS, 4oxo-EHS, 2OH-EHS, and 6OH-EHS, for the first time. Samples from 18 participants of a pre-existing dermal exposure study under real-life conditions were reassessed using a comprehensive LC-MS/MS method. EHS accounts for 34 % of the cumulative excretion of all analytes within 24 h after exposure, followed by 5OH-EHS (19 %), 5cx-EPS (18 %), 4OH-EHS (15 %) and 5oxo-EHS (11 %). Further metabolites were only quantified in minor amounts. EHS as the most prominent excretion parameter in this study demonstrates the missing first-pass effect after dermal absorption. Furthermore, the applied novel comprehensive analytical procedure revealed oxidation at the ω (5cx-EPS, 6OH-EHS), ω-1 (5OH-EHS, 5oxo-EHS), and ω-2 positions (4OH-EHS, 4oxo-EHS) in the main chain of the ethylhexyl group as well as oxidation in the side chain (2OH-EHS). The presented data are of high relevance for a reliable toxicological risk assessment of dermal exposure to EHS.

Food additive salicylates inhibit human and rat placental 3β-hydroxysteroid dehydrogenase: 3D-QSAR and in silico analysis

The use of salicylates as flavoring agents in food and beverages is common, but their potential to disrupt the endocrine system remains unclear. Human placental 3β-hydroxysteroid dehydrogenase 1 (h3β-HSD1) plays a role in progesterone synthesis and is the potential target. This study evaluated the inhibition of 13 salicylates on h3β-HSD1, structure-activity relationship (SAR) and compared with rat placental homolog r3β-HSD4. Salicylates inhibited h3β-HSD1, depending on carbon chain number in the alcohol moiety and the IC50 values for hexyl, ethylhexyl, homomenthyl, and menthyl salicylates were 53.27, 15.78, 2.35, and 2.31 μM, as mixed inhibitors, respectively, while methyl to benzyl salicylates were ineffective at 100 μM. Interestingly, only hexyl salicylate inhibited r3β-HSD4 with IC50 of 31.05 μM. Bivariate analysis revealed a negative correlation between IC50 and hydrophobicity (LogP), molecular weight, heavy atoms, and carbon number in the alcohol moiety against h3β-HSD1. Docking analysis demonstrated that these salicylates bind to cofactor binding sites or between the steroid and cofactor binding sites. Additionally, 3D-QSAR showed distinct binding via hydrogen bond donors and hydrophobic regions. In conclusion, the inhibition of h3β-HSD1 by salicylates appears to be dependent on factors such as LogP, molecular weight, heavy atoms, and carbon-chain length and there is species-dependent inhibition sensitivity.

Prenatal exposure to benzophenone-type UV filters and the associations with neonatal birth outcomes and maternal health in south China

Benzophenone (BP)-type UV filters are commonly added to sunscreens and cosmetics to protect against UV radiation for human skin and hair. As a result, BPs are ubiquitous in the environment and human body, and their endocrine-disrupting characteristics have been a hot topic of discussion. However, our knowledge regarding the detrimental effects of prenatal exposure to BPs on pregnant women and their offspring remains limited. To fill this gap, we determined five BP derivatives in 600 serum samples obtained from pregnant women. All the target analytes, except 2,4-dihydroxybenzophenone (BP-1), have achieved a 100 % detection rate. The most prevalent compound was 2-hydroxy-4-methoxybenzophenone (BP-3), with a median concentration of 0.545 ng/mL. Significant and positive correlations were observed among BP derivatives, indicating both endogenous metabolism and common external sources. Utilizing Bayesian kernel machine regression (BKMR) and quantile-based g-computation (QGC) models, we found relationships between BP exposure and reduced neonatal birth weight (BW) and birth chest circumference (BC) during the third trimester. Notably, the adverse effect of BPs on birth size was sex-specific. Moreover, triglyceride (TG) was identified as a potential mediator of the effect of BPs on blood pressure, and co-exposure to BPs was linked to disruptions in thyroid hormone levels and glucose regulation. Further research is warranted to unravel the toxicity of BPs and their detrimental effects on pregnant women and fetuses.

Combined Effects of Polystyrene Nanosphere and Homosolate Exposures on Estrogenic End Points in MCF-7 Cells and Zebrafish

BACKGROUND

Micro- and nanoplastics (MNPs) and homosalate (HMS) are ubiquitous emerging environmental contaminants detected in human samples. Despite the well-established endocrine-disrupting effects (EDEs) of HMS, the interaction between MNPs and HMS and its impact on HMS-induced EDEs remain unclear.

OBJECTIVES

This study aimed to investigate the influence of MNPs on HMS-induced estrogenic effects and elucidate the underlying mechanisms in vitro and in vivo.

METHODS

We assessed the impact of polystyrene nanospheres (PNSs; 50  nm , 1.0 mg / L ) on HMS-induced MCF-7 cell proliferation (HMS: 0.01 - 1 μ M , equivalent to 2.62 - 262 μ g / L ) using the E-SCREEN assay and explored potential mechanisms through transcriptomics. Adult zebrafish were exposed to HMS (0.0262 - 262 μ g / L ) with or without PNSs (50  nm , 1.0 mg / L ) for 21 d. EDEs were evaluated through gonadal histopathology, fertility tests, steroid hormone synthesis, and gene expression changes in the hypothalamus-pituitary-gonad-liver (HPGL) axis.

RESULTS

Coexposure of HMS and PNSs resulted in higher expression of estrogen receptor α (ESR1) and the mRNAs of target genes (pS2, AREG, and PGR), a greater estrogen-responsive element transactivation activity, and synergistic stimulation on MCF-7 cell proliferation. Knockdown of serum and glucocorticoid-regulated kinase 1 (SGK1) rescued the MCF-7 cell proliferation induced by PNSs alone or in combination with HMS. In zebrafish, coexposure showed higher expression of SGK1 and promoted ovary development but inhibited spermatogenesis. In addition, coexposure led to lower egg hatchability, higher embryonic mortality, and greater larval malformation. Coexposure also modulated steroid hormone synthesis genes (cyp17a2, hsd17[Formula: see text]1, esr2b, vtg1, and vtg2), and resulted in higher 17 β -estradiol (E 2 ) release in females. Conversely, males showed lower testosterone, E 2 , and gene expressions of cyp11a1, cyp11a2, cyp17a1, cyp17a2, and hsd17[Formula: see text]1.

DISCUSSION

PNS exposure exacerbated HMS-induced estrogenic effects via SGK1 up-regulation in MCF-7 cells and disrupting the HPGL axis in zebrafish, with gender-specific patterns. This offers new mechanistic insights and health implications of MNP and contaminant coexposure. https://doi.org/10.1289/EHP13696.

Single and mixture toxicity evaluation of avobenzone and homosalate to male zebrafish and H295R cells

Avobenzone and homosalate are widely used in sunscreens to provide ultraviolet (UV) protection, either as single compounds or in combination. Some UV filters exhibit estrogenic or anti-androgenic activities, however, studies regarding their interactions and toxicity in mixtures are limited. In this study, the effect of the toxicity of a binary mixture comprising avobenzone (0.72 μg L-1) and homosalate (1.02 and 103 μg L-1) on steroid hormone biosynthesis were investigated using male zebrafish and human adrenocortical carcinoma (H295R) cells. In fish exposed to homosalate, a significant decrease in the gonadosomatic index, testosterone level, and transcription of several genes (e.g, hsd3b2, cyp17a1, and hsd17b1) and a significant increase in the hepatosomatic index, liver steatosis, 17β-estradiol level, and transcription of vtg gene were observed. These results suggest that estrogenic and anti-androgenic effects of homosalate were mediated by the steroidogenic pathway. The presence of 0.72 μg L-1 of avobenzone augmented the anti-androgenic responses in male fish. The testosterone level in the H295R cells were significantly decreased after they were exposed to homosalate alone or in combination with avobenzone, which is consistent with observations in male zebrafish. Further studies need to be conducted to understand the endocrine disrupting properties of long-term exposure to substances typically used in sunscreens.

Comparison between endocrine activity assessed using ToxCast/Tox21 database and human plasma concentration of sunscreen active ingredients/UV filters

Sunscreen products are composed of ultraviolet (UV) filters and formulated to reduce exposure to sunlight thereby lessening skin damage. Concerns have been raised regarding the toxicity and potential endocrine disrupting (ED) effects of UV filters. The ToxCast/Tox21 program, that is, CompTox, is a high-throughput in vitro screening database of chemicals that identify adverse outcome pathways, key events, and ED potential of chemicals. Using the ToxCast/Tox21 database, octisalate, homosalate, octocrylene, oxybenzone, octinoxate, and avobenzone, 6 commonly used organic UV filters, were found to have been evaluated. These UV filters showed low potency in these bioassays with most activity detected above the range of the cytotoxic burst. The pathways that were most affected were the cell cycle and the nuclear receptor pathways. Most activity was observed in liver and kidney-based bioassays. These organic filters and their metabolites showed relatively weak ED activity when tested in bioassays measuring estrogen receptor (ER), androgen receptor (AR), thyroid receptor, and steroidogenesis activity. Except for oxybenzone, all activity in the endocrine assays occurred at concentrations greater than the cytotoxic burst. Moreover, except for oxybenzone, plasma concentrations (Cmax) measured in humans were at least 100× lower than bioactive (AC50/ACC) concentrations that produced a response in ToxCast/Tox21 assays. These data are consistent with in vivo animal/human studies showing weak or negligible endocrine activity. In sum, when considered as part of a weight-of-evidence assessment and compared with measured plasma concentrations, the results show these organic UV filters have low intrinsic biological activity and risk of toxicity including endocrine disruption in humans.

A Critical Review on the Opportunity to Use Placenta and Innovative Biomonitoring Methods to Characterize the Prenatal Chemical Exposome

Adverse effects associated with chemical exposures during pregnancy include several developmental and reproductive disorders. However, considering the tens of thousands of chemicals present on the market, the effects of chemical mixtures on the developing fetus is still likely underestimated. In this critical review, we discuss the potential to apply innovative biomonitoring methods using high-resolution mass spectrometry (HRMS) on placenta to improve the monitoring of chemical exposure during pregnancy. The physiology of the placenta and its relevance as a matrix for monitoring chemical exposures and their effects on fetal health is first outlined. We then identify several key parameters that require further investigations before placenta can be used for large-scale monitoring in a robust manner. Most critical is the need for standardization of placental sampling. Placenta is a highly heterogeneous organ, and knowledge of the intraplacenta variability of chemical composition is required to ensure unbiased and robust interindividual comparisons. Other important variables include the time of collection, the sex of the fetus, and mode of delivery. Finally, we discuss the first applications of HRMS methods on the placenta to decipher the chemical exposome and describe how the use of placenta can complement biofluids collected on the mother or the fetus.

4-Methylbenzylidene camphor triggers estrogenic effects via the brain-liver-gonad axis in zebrafish larvae

4-Methylbenzylidene camphor (4-MBC), an emerging contaminant, is a widely-used ultraviolet (UV) filter incorporated into cosmetics because it protects the skin from UV rays and counters photo-oxidation. Despite the well-established estrogenic activity of 4-MBC, the link between this activity and its effects on neurobehavior and the liver remains unknown. Thus, we exposed zebrafish larvae to environmentally relevant concentrations of 4-MBC with 1.39, 4.17, 12.5 and 15.4 μg/mL from 3 to 5 days postfertilization. We found that 4-MBC produced an estrogenic effect by intensifying fluorescence in the transgenic zebrafish, which was counteracted by co-exposure with estrogen receptor antagonist. 4-MBC-upregulated estrogen receptor alpha (erα) mRNA, and an interaction between 4-MBC and ERα suggested ERα's involvement in the 4-MBC-induced estrogenic activity. RNA sequencing unearthed 4-MBC-triggered responses in estrogen stimulus and lipid metabolism. Additionally, 4-MBC-induced hypoactivity and behavioral phenotypes were dependent on the estrogen receptor (ER) pathway. This may have been associated with the disruption of acetylcholinesterase and acetylcholine activities. As a result, 4-MBC increased vitellogenin expression and caused lipid accumulation in the liver of zebrafish larvae. Collectively, this is the first study to report 4-MBC-caused estrogenic effects through the brain-liver-gonad axis. It provides novel insight into how 4-MBC perturbs the brain and liver development.

Diastereoselective metabolism of homomenthyl salicylate (homosalate): Identification of relevant human exposure biomarkers

Homosalate (HMS) is a salicylate UV filter broadly used in sunscreens and personal care products. The aim of this study was the collection of human toxicokinetic data on HMS as a tool for risk assessment. For this purpose, metabolism and urinary excretion after a single oral HMS dose (98.2-149.1 µg (kg body weight)^-1) were investigated in four volunteers (two male, two female). As commercial products generally contain a mixture of cis- and trans-HMS, both cis-rich and trans-rich isomer mixtures were studied to investigate possible differences in metabolism. Initial metabolite screening tentatively identified six oxidative metabolite subgroups, of which hydroxylated and carboxylic acid metabolites were studied in more detail. Unchanged parent HMS and the previously identified HMS metabolites 5-((2-hydroxybenzoyl)oxy)-3,3-dimethylcyclohexane-1-carboxylic acid (HMS-CA) and 3-hydroxy-3,5,5-trimethylcyclohexyl 2-hydroxybenzoate (3OH-HMS), respectively, were quantified separately as cis- and trans-isomers via authentic standards by isotope dilution analysis. In addition, further alkyl-hydroxylated and carboxylic acid metabolites were investigated semi-quantitatively. Peak concentrations in urine were reached 1.5-6.3 h post-dose and more than 80 % of each of the quantitatively investigated metabolites (and at least 70 % of the semi-quantitatively investigated metabolites) was excreted within the first 24 h. Plasma and urine data indicated that oral bioavailability of cis-HMS was one order of magnitude below that of trans-HMS. Furthermore, the mean total urinary excretion fraction (F_ue) for the metabolites derived from trans-HMS (6.4 %) was two orders of magnitude higher than for the metabolites derived from cis-HMS (0.045 %). Our data proves diastereoselectivity in toxicokinetics of cis- and trans-HMS, emphasizing the necessity to address isomer ratios in future studies including HMS exposure and risk assessments.

Concentrations, Compound Profiles, and Possible Sources of Organic UV Filters in Human Milk in China

Ultraviolet (UV) filters are of great concern due to their wide occurrence, bioaccumulation, and toxicity. Little is known about human exposure to UV filters. A total of 3467 individual human milk samples from 24 Chinese provinces were collected during 2017-2019. The concentrations of 12 UV filters in 100 pooled milk samples were determined. The total UV filter concentration was 78-846 (mean 235 ± 120) ng/g lipid weight. The highest and lowest total mean concentrations were for samples from Qinghai and Sichuan provinces, respectively. A significant positive correlation was found between UV radiation levels and UV concentrations in the samples. The dominant UV filters were 2-(2-hydroxy-5-methylphenyl) benzotriazole (UV-P) and ethylhexyl methoxycinnamate (EHMC), which contributed means of 32 and 22%, respectively, to the total concentrations. Plastic products and sunscreens were probably the sources of UV-P and EHMC in the human milk from China, respectively. The mean 2-(3,5-di-tert-amyl-2-hydroxyphenyl) benzotriazole (UV-328) concentration was 2.6 ± 2.6 ng/g lipid weight. The UV filter profiles were similar to profiles for samples from Japan, the Philippines, and Switzerland but not for samples from Korea and Vietnam. The estimated daily UV filter intake for breastfed infants was below the corresponding reference dose. This was the first large-scale study of UV filters in human milk and will help assess the risks posed.

Evaluation of Placental Toxicity of Five Essential Oils and Their Potential Endocrine-Disrupting Effects

Pregnant women may use EOs in case of morning sickness, nausea, stress management, etc. Little is known about the potential danger that EOs represent for the placenta and therefore for the pregnancy. Our aim was to explore and compare the placental toxicity and potential endocrine disrupting effects of niaouli, orange, tea tree, wintergreen and ylang-ylang EOs, and their key compounds: 4-terpineol, 1,8-cineol, limonene, methyl salicylate and benzyl salicylate. We studied the release of four hormones and the activation of P2X7 receptor in JEG-Tox human placental cells as key biomarkers for endocrine toxicity. We observed that niaouli, orange, tea tree, wintergreen and ylang-ylang EOs and their key components disrupted at least one of the studied hormones but none of them activated the P2X7 cell death receptor. The tested EOs appear then to be more hormonal modulators rather than EDCs in human placental cells. The hormonal effects observed with the key components were very different from those observed with the EOs. EOs are very complex mixtures, and it is essential to study whole EOs rather than their components individually in safety assessment.

Pregnant Women and Endocrine Disruptors: Role of P2X7 Receptor and Mitochondrial Alterations in Placental Cell Disorders

In pregnant women, the lungs, skin and placenta are exposed daily to endocrine-disrupting chemicals (EDCs). EDCs induce multiple adverse effects, not only on endocrine organs, but also on non-endocrine organs, with the P2X7 cell death receptor being potentially the common key element. Our objective was first to investigate mechanisms of EDCs toxicity in both endocrine and non-endocrine cells through P2X7 receptor activation, and second, to compare the level of activation in lung, skin and placental cells. In addition, apoptosis in placental cells was studied because the placenta is the most exposed organ to EDCs and has essential endocrine functions. A total of nine EDCs were evaluated on three human cell models. We observed that the P2X7 receptor was not activated by EDCs in lung non-endocrine cells but was activated in skin and placenta cells, with the highest activation in placenta cells. P2X7 receptor activation and apoptosis are pathways shared by all tested EDCs in endocrine placental cells. P2X7 receptor activation along with apoptosis induction could be key elements in understanding endocrine placental and skin disorders induced by EDCs.

Occurrence of major organic UV filters in aquatic environments and their endocrine disruption potentials: A mini-review

Organic UV filters are frequently used in daily life, and hence are ubiquitously detected in the aquatic environment worldwide. Most monitoring efforts and toxicological studies are, however, limited to a few chemicals like benzophenone-3 (BP-3). In the present study, we chose other major organic UV filters, such as avobenzone (AVB), homosalate (HS), octisalate (OS), and octocrylene (OC), and reviewed information on their use, environmental occurrences, and endocrine disruption effects, available to date. Organic UV filters are used in high volume in many consumer applications, not only in sunscreen products but also in cosmetics, personal care products, home products, and food packaging. Environmental monitoring worldwide reveals that recreational coastal waters are among the hot spots of their contamination. An increasing number of experimental studies indicate that organic UV filters such as octinoxate (OMC), AVB, and HS may cause disruptions in sex hormones. Avobenzene and OMC can also influence thyroid function in experimental models. Observations in human population are rarely made, but OMC and OC have been associated with decreased androgenicity and increase of polycystic ovary syndrome, respectively. Further investigations are warranted to fill the knowledge gaps identified in the present study, to help develop relevant safety screening measures for organic UV filters. Integr Environ Assess Manag 2021;17:940-950. © 2021 SETAC.

A critical assessment of the estrogenic potency of benzyl salicylate

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Benzyl salicylate (BS) is on priority lists for evaluation of estrogenic effects.

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New data in both MCF7 (E-screen) and luciferase transactivation assays.

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Potency of BS is 21′000′000-fold lower than estradiol in transactivation assay.

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Potency of BS is 36′000′000-fold lower than estradiol in E-screen.

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Potency is > 1000-fold below human relevant potency threshold.

Benzyl salicylate (BS) is a natural ingredient of essential oils and a widely used fragrance chemical. A number of in vitro screening studies have evaluated the estrogenic potential of BS with ambiguous results. Lack of dose-response information for the positive control 17β-estradiol (E2) in most studies makes an assessment of the relative potency and efficacy challenging. Notwithstanding this difficulty, BS has been added as the only fragrance ingredient to the list of the first 14 substances to be screened as potential endocrine disruptors by the European Scientific Committee for Consumer Safety (SCCS) and it is included in the Community rolling action plan (CoRAP) of the European REACH regulation to be assessed for the same property. Here we review all literature evidence and present new data to quantify the in vitro potency and efficacy of BS vs. E2 with full dose response analysis in both an estrogen response element (ERE) depending reporter gene assay and in the MCF7 cell proliferation (E-screen) assay. In both assays, very similar results for BS were found. BS is a partial agonist exhibiting 35–47 % maximal efficacy and it is active only close to the cytotoxic concentration. The extrapolated concentration to achieve 50 % efficacy is 21′000′000 higher as compared to E2 in the reporter gene assay. A ca. 36′000′000 higher concentration of BS as compared to E2 is required to reach equivalent partial cell proliferation stimulation in the MCF7 proliferation assay. This potency is significantly below the agonistic activity of known chemicals which cause estrogenic effects in in vivo assays. Importantly, in this study the weak agonistic activity is for the first time directly related to the activity of E2 in a full quantitative comparison in human cell lines which may help ongoing evaluations of BS by regulatory bodies.

Investigation of endocrine disruptor pollutants and their metabolites along the Romanian Black Sea Coast: Occurrence, distribution and risk assessment

In recent years, the occurrence of organic UV-filters (UVFs) and bisphenol derivatives (BPs) in the marine environment has raised high concerns all over the world, due to the potentially adverse impacts on marine organism and, indirectly on human health. This paper reports, for the first time in Romania, the occurrence, distribution pattern and environmental risk assessment of UVFs, BPs and their metabolites in seawater, sediment and algae collected from the Romania Black Sea coastal region. BP-3 (2-hydroxy-4-methoxy-benzophenone) was the most abundant contaminant in seawater samples, with detection frequency of 100 %. Sediment samples were dominated by ES (Ethylhexyl salicylate), with concentration values up to 5823 ng/g d.w., while for algae, concentrations of several hundreds of ng/g d.w. were determined for BP-3, BS (Benzyl salicylate) and BPE (Bisphenol E). Environmental risk assessment revealed that some UVFs and BPs detected in seawater samples were hazardous to the marine organism of the Black Sea.

Determination of urinary metabolites of the UV filter homosalate by online-SPE-LC-MS/MS

Homosalate (HMS) is an organic UV filter used in sunscreens and personal care products worldwide. It has been detected in various environmental matrices and in humans after application of HMS-containing products. However, sufficient data on the internal HMS exposure in humans is currently not available. Thus, we aimed at providing an analytical method for the sensitive determination of specific HMS metabolites in human urine. We describe the synthesis of analytical standards for the four oxidative HMS metabolites included in this method: 5-((2-hydroxybenzoyl)oxy)-3,3-dimethylcyclohexane-1-carboxylic acid (HMS-CA) and 3-hydroxy-3,5,5-trimethylcyclohexyl 2-hydroxybenzoate (3OH-HMS), as cis- and trans-isomers, respectively. After enzymatic hydrolysis, urine samples were analyzed using liquid chromatography-electrospray ionization-triple quadrupole-tandem mass spectrometry, including turbulent flow chromatography for online sample cleanup and analyte enrichment (online-SPE-LC-MS/MS). Quantification was performed by stable isotope dilution analysis, using deuterium-labeled HMS-CA as internal standards (cis and trans). Limits of quantification of 0.02-0.04 μg L^-1 were sufficiently low to quantify the HMS metabolites for up to 96 h (trans-HMS-CA), 48 h (cis-HMS-CA and 3OH-trans-HMS), and 24 h (3OH-cis-HMS) after a pilot dermal application of a commercially available sunscreen in one human volunteer, showing clear elimination kinetics. Furthermore, in a German pilot population (n = 35), HMS metabolites were above the LOQ precisely in those three individuals who had applied sunscreen within the previous five days, thus corroborating the specificity of the identified metabolites as biomarkers of HMS exposure. The method is currently used in a human metabolism study and will be applied in future population-scale human biomonitoring studies.

Sunscreens and their usefulness: have we made any progress in the last two decades?

Sunscreens have now been around for decades to mitigate the Sun's damaging ultraviolet (UV) radiation which, although essential for the existence of life, is a recognized prime carcinogen. Accordingly, have suncreams achieved their intended purposes towards protection against sunburns, skin photo-ageing and the like? Most importantly, however, have they provided the expected protection against skin cancers that current sunscreen products claim to do? In the last two decades, there have been tens, if not hundreds of studies on sunscreens with respect to skin protection against UVB (280‒320 nm)-traditionally sunscreens with rather low sun protection factors (SPF) were intended to protect against this type of radiation-and UVA (320‒400 nm) radiation; a distinction between SPF and UVA protection factor (UVA-PF) is made. Many of the studies of the last two decades have focused on protection against the more skin-penetrating UVA radiation. This non-exhaustive article reviews some of the important facets of what is currently known about sunscreens with regard (i) to the physical UV filters titanium dioxide (TiO₂) and zinc oxide (ZnO) and the mostly photo-unstable chemical UVB/UVA filters (e.g., octinoxate (OMC) and avobenzone (AVO), among others), (ii) to novel chemical sunscreen agents, (iii) to means that minimize the breakdown of chemical filters and improve their stability when exposed to UV sunlight, (iv) to SPF factors, and (v) to a short discussion on non-melanoma skin cancers and melanoma. Importantly, throughout the article we allude to the safety aspects of sunscreens and at the end ask the question: do active ingredients in sunscreen products pose a risk to human health, and what else can be done to enhance protection? Significant loss of skin protection from two well-known commercial suncreams when exposed to simulated UV sunlight. Cream I: titanium dioxide, ethylhexyl triazone, avobenzone, and octinoxate; Cream II: octyl salicylate, oxybenzone, avobenzone, and octinoxate.

Development and validation of LC-MS/MS method for the determination of UV-filters across human skin in vitro

A novel High-Performance Liquid Chromatography-Tandem Mass Spectrometry (HPLC-MS/MS) method was developed for the simultaneous determination of the in vitro skin permeation profile of four UV filters. The sunscreen products contained the following components: octocrylene (OC), ethylhexyl methoxycinnamate (EHMC), diethylamino hydroxybenzoyl hexyl benzonate (DHHB) and ethylhexyl salicylate (EHS). The target compounds were analyzed by HPLC-MS/MS method in positive ionization electrospray (ESI) in Multiple Reaction Monitoring (MRM) mode. The proposed method was validated in terms of the detection (LOD) and quantification limits (LOQ), linearity range, intra- and inter- day precision and accuracy of the analysis. The stability of the target compounds in solutions was also studied. All tests provided satisfactory results illustrating acceptable method performance. Samples were analyzed with simple pretreatment procedure, necessary to achieve solvent change and preconcentration. To evaluate matrix effect, the slopes of the standard regression curves with those of the matrix-matched calibration curves were compared using the Student's t-test. Quantitative evaluation of the test samples was performed using external methanolic calibration curves. Accuracy was found within the range 94.37-108.76%. The method was successfully applied to the analysis of UV filters in samples after permeability studies, in Franz's cells, for 24 h, using human skin. Concentration of sunscreens in the acceptor phase at the timescale of 24 h was very low implying the safety of the products.

Sensitization to benzyl salicylate and other allergens in patients with frontal fibrosing alopecia

BACKGROUND

Contact sensitization is frequent among patients with frontal fibrosing alopecia (FFA) (52%-76%).

OBJECTIVE

To evaluate the frequency of sensitization/photosensitization in an FFA population.

METHODS

A population of FFA patients were patch tested (Spanish Contact Dermatitis Research Group [GEIDAC] baseline; cosmetic and fragrance series), and photopatch tested (sunscreen series).

RESULTS

Thirty-six patients (mean age: 64.6 years; 35/36: women) were studied. A history of dermatitis was recorded in 69.4% (frequently involving the face). Overall, 80.5% patients showed positive patch-test reactions. The most frequently positive allergens were nickel sulfate (25%), benzyl salicylate (22%), gallates (16.6%), propolis (16.6%), and limonene hydroperoxides (13.8%). Benzyl salicylate was likely relevant to the dermatitis (labeled on personal care products and most patients reporting clinical improvement with allergen avoidance). Patch tests with sunscreens showed positive reactions to 11 materials (five patients). Photopatch tests were positive in one case.

CONCLUSION

We speculate a possible relationship between sensitization to benzyl salicylate and FFA. Hypothetically, the most likely explanation is that sensitization to benzyl salicylate involving FFA patients is a consequence of increased exposure to it. It is unclear whether allergen avoidance may impact the prognosis of alopecia. However, it seems to significantly improve the patients´ quality of life by lessening dermatitis and pruritus.

Distribution, removal efficiencies and environmental risk assessment of benzophenone and salicylate UV filters in WWTPs and surface waters from Romania

This article presents the environmental pollution level with organic UV filters and the effect they pose on aquatic organisms in Romania.

[Power station sun and hormone factory skin : A current assessment of the importance of vitamin D metabolism during human evolution and strategies for UV prevention]

The sun is of great importance for human health. One important reason for this is the production of vitamin D, endorphins and many other hormones by the skin due to stimulation by sunlight. Insufficient access to sunlight increases the risk for vitamin D deficiency, a pandemic which would affect more than one billion people worldwide and under which ca. 60% of the population in Germany would suffer. The skin has a unique position in vitamin D metabolism as elementary steps for vitamin D production take place here and it is furthermore a target organ for actions of vitamin D. Due to the many positive effects of the sun, a healthy balance must be found between UV protection to shield against skin cancer but also ensuring sufficient vitamin D production. For regulation of this fragile balance between photoprotection and vitamin D production, which has accompanied mankind throughout evolution, sunscreens are an integral part of the modern lifestyle, although critical reports on possible risks for their use have recently become more frequent. This article discusses the current state of knowledge on the importance of vitamin D metabolism in human skin and the use of sun creams.

Ensuring the Safety of Sunscreens, and Their Efficacy in Preventing Skin Cancers: Challenges and Controversies for Clinicians, Formulators, and Regulators

When people think about sun-protection or prevention of skin cancer, sunscreens readily come to mind. Sunscreen effectiveness is tested in vivo by the ability to prevent erythema of skin, yet testing methods vary between markets, and many sunscreens fail to achieve their claims. This article discusses the mechanism of action of sunscreens, Sun Protection Factor (SPF), safety concerns and the challenges for regulators. Many sunscreens that prevent erythema do not provide adequate protection as they contain anti-inflammatory agents; others have ingredients whose risks have not been fully evaluated. This article reviews the imperfect science behind sunscreens and points out the gaps in knowledge regarding safety, efficacy, public knowledge, and perception. Regulations vary between countries and only adds to the confusion. To truly prevent skin cancer, clinicians, formulators and regulators need to come together to research more and improve public education.

A mechanism for the effect of endocrine disrupting chemicals on placentation

Numerous recent studies have shown that endocrine disrupting chemicals (EDCs) in the body of pregnant women can pass through the placenta and be exposed to the fetus, leading to fetal development and cognitive impairment. Placentation through invasion of trophoblast cells and vascular remodeling is essential to maintaining maternal and fetal health throughout the pregnancy. Abnormal placentation can lead to pregnancy disorders such as preeclampsia (PE) and intrauterine growth retardation (IUGR). However, many studies have not been conducted on whether EDCs can inhibit the development and function of the placenta. Isolating placental tissues to analyze the effect of EDCs on placentation has several limitations. In this review, we discussed the types of EDCs that can pass through the placental barrier and accumulate in the placenta with relative outcome. EDCs can be released from a variety of products including plasticizers, pesticides, and retardant. We also discussed the development and dysfunction of the placenta when EDCs were treated on trophoblast cells or pregnant rodent models. The effects of EDCs on the placenta of livestock are also discussed, together with the molecular mechanism of EDCs acting in trophoblast cells. We describe how EDCs cross the membrane of trophoblasts to regulate signaling pathways, causing genetic and epigenetic changes that lead to changes in cell viability and invasiveness. Further studies on the effects of EDCs on placenta may draw attention to the correct use of products containing EDCs during pregnancy.

Renal and testicular up-regulation of pro-inflammatory chemokines (RANTES and CCL2) and cytokines (TNF-α, IL-1β, IL-6) following acute edible camphor administration is through activation of NF-kB in rats

Camphor-induced oxidative stress and histopathological changes (in brain, lung, liver, kidney and testes) have been reported. We therefore investigated the effect of various doses of camphor in an acute study, on renal and testicular levels of some pro-inflammatory mediators in male wistar rats. Twenty rats divided into four groups of five rats each were used in this study. Group 1 served as control and was administered 6 mL/kg olive oil, the vehicle for camphor, while groups 2, 3 and 4 were orally administered 1000, 2000, and 4000 mg/kg body weight camphor, for seven days. Compared with control, levels of tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β) and interleukin 6 (IL-6) were significantly increased kidney and testes by 2000 and 4000 mg/kg body weight, while interleukin 10 (IL-10) was only significantly increased by 1000 mg/kg body weight of camphor in both tissues. Also compared with control, all doses of camphor administered resulted in a significant increase in the expressions of renal and testicular nuclear factor kappa B (NFkB), cyclooxygenase 2 (COX-2), regulated upon activation normal T cell expressed and secreted (RANTES), and monocyte chemo-attractant protein 1 (MCP-1). Conclusively, use and consumption of camphor should be with caution as it could trigger renal and testicular inflammation through activation of NF-kB and up-regulation of pro-inflammatory markers.

Urinary concentration of personal care products and polycystic ovary syndrome: A case-control study

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorder among females of reproductive age. Many emerging contaminants in personal care products have been confirmed with endocrine disruptive effects. We performed a case-control study to explore the association between the concentrations of certain emerging contaminants (organic UV filters, bisphenol A, and triclosan) and the risk of PCOS. Urine samples were collected from 40 women with PCOS (case group) and 83 healthy women (control group). No significant differences were found in detection rate or total concentrations of analytes in women with PCOS and controls (p > 0.05). In addition, no association was found between certain emerging contaminants and PCOS either in an unadjusted binary logistic regression model or in a model adjusted for potential confounders. However, with stratification according to body mass index, one organic UV filter - octocrylene(OC) was significantly associated with PCOS in women with BMI ≥ 24 (adjusted OR = 1.512, 95% CI: 1.043, 2.191). It's the first time to investigate the association between exposure of organic UV filters and PCOS risk. We conclude that there is positive association between OC and PCOS risk in obese and overweight women.

Exposure to the UV Filter Octyl Methoxy Cinnamate in the Postnatal Period Induces Thyroid Dysregulation and Perturbs the Immune System of Mice

Evidence demonstrates the bidirectional communication and regulation between the neuroendocrine and immune systems. Thyroid hormones play key roles in nervous system development and can exert influence on various immune cells contributing to pathophysiological conditions. Octyl methoxycinnamate (OMC) is one of the most commonly used UV filters, and in vitro and in vivo studies have found thyroid disrupting effects. The present study assessed whether OMC administration in mice dams during the lactational period can cause thyroid disruption and generate immunologic alterations in the offspring. Indirect exposure to the OMC (1,000 mg/kg) in the lactational period affected neurodevelopment parameters, such as delayed eye-opening and weight gain in mice of both sexes, and these alterations are corroborated by the decrease in the T4 levels present in the pups' blood. No significant changes were observed in the thymus of these pups, but the number of lymphocytes increased in the spleen of the animals exposed to OMC, similar to the animals treated with propyl-thiouracil (PTU), a well-known thyroid disruptor. OMC modulated the percentage of leukocyte populations in peripheral blood, and the number of circulating polymorphonuclear cells increased two-fold. In vitro, OMC exhibited an inhibitory effect on splenocyte proliferation and IL-2 production induced by anti-CD3 antibody; however, this effect was reversed with the addition of T4 in the cell culture. In summary, the results of the present study demonstrate the influence of OMC on thyroid dysregulation and its impact on the modulation of the immune system in mice pups.

Homosalate aggravates the invasion of human trophoblast cells as well as regulates intracellular signaling pathways including PI3K/AKT and MAPK pathways

Homosalate is an organic ultraviolet filter used in most sunscreens but has been reported to be toxic to marine organisms. The estrogenic activity of homosalate has also been reported, but its endocrine-disrupting effect remains unclear. Although homosalate has been detected in human placental tissues, its effect on the survival of human trophoblast cells needs to be investigated. Therefore, in this study, we evaluated if HTR8/SVneo, a human trophoblast cell line, treated with homosalate showed decreasing proliferative activity in a dose-dependent manner. Homosalate promoted the death of HTR8/SVneo cells with elevated lipid peroxidation and intracellular Ca²⁺ concentration. It also induced endoplasmic reticulum stress and mitochondrial morphological disturbances associated with the differentiation of human trophoblast cells. However, when the intracellular Ca²⁺ or reactive oxygen species were removed using BAPTA-AM or N-acetyl-L-cysteine (NAC), the cell proliferation suppressed by homosalate was restored. Homosalate also significantly inhibited the invasion of HTR8/SVneo cells. Furthermore, it modulated phosphoinositide 3-kinase (PI3K)/AKT and mitogen-activated protein kinase (MAPK) signaling pathways, which were involved in the cross-talk between both signaling pathways in HTR8/SVneo cells. Thus, homosalate adversely affects the survival, proliferation, and invasiveness of human trophoblast cells and therefore pregnant women should practice caution while using personal care products containing homosalate.

Investigation of cis-trans isomer dependent dermatotoxicokinetics of UV filter ethylhexyl methoxycinnamate through stratum corneum in vivo

2-Ethylhexyl methoxycinnamate (EHMC) is one of the most used ultraviolet filters in personal care products. It undergoes cis/trans isomerization in sunlight, and there is limited toxicological understanding of the effects of the cis-isomer. It is known that two geometric isomers of one compound can have different physico-chemical properties and effects. However, there are no studies focusing on toxicokinetics of EHMC isomerization products to compare their potential difference in dermal exposure to cis-EHMC and trans-EHMC due to the difference in their dermatotoxicokinetics. In this study, dermal absorption of the parental trans-EHMC and its cis isomer was studied. A commercially available sunscreen lotion containing trans-EHMC and spiked with laboratory-prepared cis-EHMC was locally applied on the forearm skin of two volunteers. After 8 h of skin exposure, the stratum corneum (SC) layer was removed by tape stripping. The removed thickness of the SC was determined spectrophotometrically using a total protein assay. The concentration of both isomers in the removed SC was measured by HPLC-DAD. A new diffusion and permeability coefficient of both EHMC isomers in SC were determined by Fick's second law of diffusion in vivo. The difference in dermatotoxicokinetic parameters between the two isomers was not statistically significant. However, separate toxicological studies of isomeric forms and the determination of their dermatotoxicokinetic parameters are crucial for refinement of human risk assessment.

Different DNA damage response of cis and trans isomers of commonly used UV filter after the exposure on adult human liver stem cells and human lymphoblastoid cells

2-ethylhexyl 4-methoxycinnamate (EHMC), used in many categories of personal care products (PCPs), is one of the most discussed ultraviolet filters because of its endocrine-disrupting effects. EHMC is unstable in sunlight and can be transformed from trans-EHMC to emergent cis-EHMC. Toxicological studies are focusing only on trans-EHMC; thus the toxicological data for cis-EHMC are missing. In this study, the in vitro genotoxic effects of trans- and cis-EHMC on adult human liver stem cells HL1-hT1 and human-derived lymphoblastoid cells TK-6 using a high-throughput comet assay were studied. TK-6 cells treated with cis-EHMC showed a high level of DNA damage when compared to untreated cells in concentrations 1.56 to 25μgmL^-1. trans-EHMC showed genotoxicity after exposure to the two highest concentrations 12.5 and 25μgmL^-1. The increase in DNA damage on HL1-hT1 cells induced by cis-EHMC and trans-EHMC was detected at the concentration 25μgmL^-1. The No observed adverse effect level (NOAEL, mg kg^-1bwday^-1) was determined using a Quantitative in vitro to in vivo extrapolation (QIVIVE) approach: NOAEL_trans-EHMC=3.07, NOAEL_cis-EHMC=0.30 for TK-6 and NOAEL_trans-EHMC=26.46, NOAEL_cis-EHMC=20.36 for HL1-hT1. The hazard index (HI) was evaluated by comparing the reference dose (RfD, mgkg^-1bwday^-1) obtained from our experimental data with the chronic daily intake (CDI) of the female population. Using comet assay experimental data with the more sensitive TK-6 cells, HI_cis-EHMC was 7 times higher than HI_trans-EHMC. In terms of CDI, relative contributions were; dermal exposure route>oral>inhalation. According to our results we recommend the RfD_trans-EHMC=0.20 and RfD_cis-EHMC=0.02 for trans-EHMC and cis-EHMC, respectively, to use for human health risk assessment. The significant difference in trans-EHMC and cis-EHMC response points to the need for toxicological reevaluation and application reassessment of both isomers in PCPs.

Neurotoxic effect of active ingredients in sunscreen products, a contemporary review

Sunscreen application is the main strategy used to prevent the maladies inflicted by ultraviolet (UV) radiation. Despite the continuously increasing frequency of sunscreen use worldwide, the prevalence of certain sun exposure-related pathologies, mainly malignant melanoma, is also on the rise. In the past century, a variety of protective agents against UV exposure have been developed. Physical filters scatter and reflect UV rays and chemical filters absorb those rays. Alongside the evidence for increasing levels of these agents in the environment, which leads to indirect exposure of wildlife and humans, recent studies suggest a toxicological nature for some of these agents. Reviews on the role of these agents in developmental and endocrine impairments (both pathology and related mechanisms) are based on both animal and human studies, yet information regarding the potential neurotoxicity of these agents is scant. In this review, data regarding the neurotoxicity of several organic filters: octyl methoxycinnamate, benzophenone-3 and −4, 4-methylbenzylidene camphor, 3-benzylidene camphor and octocrylene, and two allowed inorganic filters: zinc oxide and titanium dioxide, is presented and discussed. Taken together, this review advocates revisiting the current safety and regulation of specific sunscreens and investing in alternative UV protection technologies.

Assessment of parabens and ultraviolet filters in human placenta tissue by ultrasound-assisted extraction and ultra-high performance liquid chromatography-tandem mass spectrometry

Increasing concerns have been raised over recent decades about human exposure to Endocrine Disrupting Chemicals (EDCs), especially about their possible effects on embryo, foetus, newborn, and child. Parabens (PBs) and ultraviolet filters (UV-filters) are prevalent EDCs widely used as additives in cosmetics and personal care products (PCPs). The objective of this study was to determine the presence of four PBs and ten UV-filters in placental tissue samples using a novel analytical method based on ultrasound-assisted extraction (UAE) and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Multivariate optimization strategies were used to accurately optimize extraction and clean-up parameters. Limits of quantification ranged from 0.15 to 0.5μgkg^-1, and inter-day variability (evaluated as relative standard deviation) ranged from 3.6% to 14%. The method was validated using matrix-matched standard calibration followed by a recovery assay with spiked samples. Recovery percents ranged from 94.5% to 112%. The method was satisfactorily applied for the determination of the target compounds in human placental tissue samples collected at delivery from 15 randomly selected women. This new analytical procedure can provide information on foetal exposure to compounds, which has been little studied.

Recent Advances on Endocrine Disrupting Effects of UV Filters

Ultraviolet (UV) filters are used widely in cosmetics, plastics, adhesives and other industrial products to protect human skin or products against direct exposure to deleterious UV radiation. With growing usage and mis-disposition of UV filters, they currently represent a new class of contaminants of emerging concern with increasingly reported adverse effects to humans and other organisms. Exposure to UV filters induce various endocrine disrupting effects, as revealed by increasing number of toxicological studies performed in recent years. It is necessary to compile a systematic review on the current research status on endocrine disrupting effects of UV filters toward different organisms. We therefore summarized the recent advances on the evaluation of the potential endocrine disruptors and the mechanism of toxicity for many kinds of UV filters such as benzophenones, camphor derivatives and cinnamate derivatives.

UV filters induce transcriptional changes of different hormonal receptors in Chironomus riparius embryos and larvae

Organic ultraviolet (UV) filters are emerging contaminants that are ubiquitous in fresh and marine aquatic systems due to their extensive use in cosmetics, plastics, paints, textiles, and many other industrial products. The estrogenic effects of organic UV filters have been long demonstrated in vertebrates, and other hormonal activities may be altered, according to more recent reports. The impact of UV filters on the endocrine system of invertebrates is largely unknown. We have previously reported that some UV filters may affect ecdysone-related genes in the aquatic insect Chironomus riparius, an ecotoxicologically important model organism. To further analyze other possible effects on endocrine pathways, we first characterized four pivotal genes related with hormonal pathways in insects; thereafter, these genes were assessed for alterations in transcriptional activity after exposure to 4-methylbenzylidene camphor (4MBC) or benzophenone-3 (BP-3), two extensively used sunscreens. We found that both chemicals disturbed the expression of all four genes analyzed: hormonal receptor 38 (HR38), methoprene-tolerant (Met), membrane-associate progesterone receptor (MAPR) and insulin-like receptor (INSR), measured by changes in mRNA levels by real-time PCR. An upregulatory effect at the genomic level was detected in different developmental stages. Interestingly, embryos appeared to be more sensitive to the action of the UV filters than larvae. Our results suggest that the risk of disruption through different endocrine routes is not negligible, considering the significant effects of UV filters on key hormonal receptor and regulatory genes. Further effort is needed to develop environmental risk assessment studies on these pollutants, particularly for aquatic invertebrate model organisms.

Kinetics of Chlorination of Benzophenone-3 in the Presence of Bromide and Ammonia

The aim of this study was to assess the impact of chlorination on the degradation of one of the most commonly used UV filters (benzophenone-3 (BP-3)) and the effects of bromide and ammonia on the kinetics of BP-3 elimination. Bromide and ammonia are rapidly converted to bromine and chloramines during chlorination. At first, the rate constants of chlorine, bromine and monochloramine with BP-3 were determined at various pH levels. BP-3 was found to react rapidly with chlorine and bromine, with values of apparent second order rate constants equal to 1.25(±0.14) × 10(3) M(-1)·s(-1) and 4.04(±0.54) × 10(6) M(-1)·s(-1) at pH 8.5 for kChlorine/BP-3 and kBromine/BP-3, respectively, whereas low monochloramine reactivity was observed (kNH2Cl/BP-3 = 0.112 M(-1)·s(-1)). To assess the impact of the inorganic content of water on BP-3 degradation, chlorination experiments with different added concentrations of bromide and/or ammonia were conducted. Under these conditions, BP-3 degradation was found to be enhanced in the presence of bromide due to the formation of bromine, whereas it was inhibited in the presence of ammonia. However, the results obtained were pH dependent. Finally, a kinetic model considering 18 reactions was developed using Copasi to estimate BP-3 degradation during chlorination in the presence of bromide and ammonia.

Development of an analytical method for the targeted screening and multi-residue quantification of environmental contaminants in urine by liquid chromatography coupled to high resolution mass spectrometry for evaluation of human exposures

The aim of this study was to develop an analytical method and contribute to the assessment of the Exposome. Thus, a targeted analysis of a wide range of contaminants in contact with humans on daily routines in urine was developed. The method focused on a list of 38 contaminants, including 12 pesticides, one metabolite of pesticide, seven veterinary drugs, five parabens, one UV filter, one plastic additive, two surfactants and nine substances found in different products present in the everyday human environment. These contaminants were analyzed by high performance liquid chromatography coupled to high resolution mass spectrometry (HPLC-HRMS) with a quadrupole-time-of-flight (QqToF) instrument from a raw urinary matrix. A validation according to the FDA guidelines was employed to evaluate the specificity, linear or quadratic curve fitting, inter- and intra-day precision, accuracy and limits of detection and quantification (LOQ). The developed analysis allows for the quantification of 23 contaminants in the urine samples, with the LOQs ranging between 4.3 ng.mL(-1) and 113.2 ng.mL(-1). This method was applied to 17 urine samples. Among the targeted contaminants, four compounds were detected in samples. One of the contaminants (tributyl phosphate) was detected below the LOQ. The three others (4-hydroxybenzoic acid, sodium dodecylbenzenesulfonate and O,O-diethyl thiophosphate potassium) were detected but did not fulfill the validation criteria for quantification. Among these four compounds, two of them were found in all samples: tributyl phosphate and the surfactant sodium dodecylbenzenesulfonate.

WITHDRAWN: The potential contribution of endocrine disrupting chemicals to acne

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A novel biomarker for anti-androgenic activity in placenta reveals risks of urogenital malformations

It has been hypothesized that the rise in male reproductive disorders over recent decades may at least be partially attributable to environmental factors, including chemical exposures, but observed associations with single chemicals were rather weak. The aim of this case-control study was to explore the relationship between exposure to mixtures of (anti-)androgenic chemicals during pregnancy and the risk of cryptorchidism and/or hypospadias in offspring, using the total effective xenobiotic burden of anti-androgens (TEXB-AA) as a biomarker. A subsample of 29 cases (16 of cryptorchidism, 12 of hypospadias, and one of both disorders) and 60 healthy controls was nested in a cohort of male newborns recruited between October 2000 and July 2002. The (anti-)androgenic activity of placenta samples collected at delivery was assessed using TEXB-AA biomarker, combined with a bioassay-directed fractionation protocol that separated endogenous hormones from most (anti-)androgenic chemicals by normal-phase HPLC. The bioassay measures the androgen-induced luciferase activity and the inhibition of this pathway by (anti-)androgens. First, we collected 27 HPLC fractions in each placenta extract, which were all tested in the bioassay. The multivariable statistical analyses indicated a statistically significant positive dose-response association between the potent anti-androgenic activity of the HPLC fraction collected during minutes 1-2 (F2) and the risk of malformations (odds ratio: 2.33, 95% CI: 1.04-5.23). This study represents a novel approach for the estimation of combined effects of the total anti-androgenic load and the associations suggest an effect of environmental pollutants on the development of fetal reproductive tract.Free Spanish abstract: A Spanish translation of this abstract is freely available at http://www.reproduction-online.org/content/149/6/605/suppl/DC1.

Study of the transformation of two salicylates used in personal care products in chlorinated water

Disinfection of swimming pool water is essential to inactivate pathogenic microorganisms. However chlorine based disinfectants, the most commonly used, are known to lead to the formation of disinfection by-products (DBPs), some of which have been associated with adverse health effects. Precursors of DBPs include the organic matter present in the water used to fill the swimming pool, human body fluids and personal care products (PCPs) used by swimmers and bathers. The increased use, in the last years, of PCPs lead to an increased concern about the fate of PCPs in swimming pool waters and potential health risks of formed DBPs. In this study, the chemical transformations of two salicylates, benzyl salicylate (BzS) and phenyl salicylate (PS), incorporated in several PCPs, in chlorinated water were investigated. High-performance liquid chromatography (HPLC) with UV-diode-array detection (HPLC-UV-DAD) was used to follow the reaction kinetics and HPLC with mass spectrometry (HPLC-MS) was used to tentatively identify the major transformation by-products. Under the experimental conditions used in this work both salicylates reacted with chlorine following pseudo-first order kinetics: rate constant k = (0.0038 ± 0.0002) min(-1) and half-life t1/2 = (182 ± 10) min for BzS and rate constant k = (0.0088 ± 0.0005) min(-1) and half-life t1/2 = (79 ± 4) min for PS (mean ± standard deviation). The reactions of the two salicylates in chlorinated water led to the formation of DBPs that were tentatively identified as mono- and dichloro- substituted compounds. Most probably they result from an electrophilic substitution of one or two hydrogen atoms in the phenolic ring of both salicylates by one or two chlorine atoms.