A review of sources, pathways, and toxic effects of human exposure to benzophenone ultraviolet light filters

A novel approach for unveiling co-occurrence patterns of UV filter mixtures in sunscreens: Prioritization for hazard and risk assessment

In recent years, concerns regarding the toxicity of organic UV filters in sunscreen products have increased. While sunscreen products contain multiple UV filters in combination, current understanding on their co-occurrence patterns and mixture toxicities is still limited. This study utilized a public database, "Hwahae", and analyzed 2183 sunscreen products marketed in South Korea as of 2019, using an association rule mining (ARM) to elucidate their co-occurrence patterns. We identified twenty-two UV filters in the sunscreen products, with titanium dioxide (TiO2) being the most prevalent (68 %), followed by ethylhexyl methoxycinnamate (EHMC, 60 %) and ethylhexyl salicylate (EHS, 49 %). Sunscreen products typically contained a median of five UV filters per product. Usage patterns of UV filter mixtures varied by the target user group of the product, i.e., general, susceptible, and male users. EHMC and EHS were commonly combined in most products, except those marketed for susceptible users. For susceptible users, inorganic UV filters such as TiO2 and zinc oxide (ZnO) were dominantly used. Combinations of UV filters that provide protection against different types of UV light, e.g., butyl methoxydibenzoylmethane (BMDBM) for UVA, and octocrylene (OCT), EHS, or homosalate (HS) for UVB, were also frequently used together, with high lift values. In conclusion, our study demonstrated that ARM approach can be useful to identify major combinations of UV filters present in sunscreen products, and prioritize the UV filter combinations requiring safety assessment and regulatory attention.

Genetic Evidence for Estrogenic Effects of Benzophenone-2 on Zebrafish Neurodevelopment and Its Signaling Mechanism

Estrogens play a crucial role in regulating various biological responses during the early stages of neurodevelopment. Benzophenone-2 (BP2), a widely used organic ultraviolet (UV) filter, has been proven as an estrogenic compound, whereas the estrogenic effects of BP2 on neurodevelopment remain largely unknown. Here, we investigated the neurodevelopmental toxicity of BP2 by exposing zebrafish embryos from 2 to 120 h postfertilization (hpf) at environmentally relevant concentrations. We demonstrated that early life exposure to BP2 induced multiple concentration-dependent impairments in the nervous system, including hypoactivity, abnormal brain morphology, impaired neurocyte proliferation, shortened axon, and increased neurocyte apoptosis. Moreover, metabolomic profiling revealed a decrease in dopamine (DA) and its metabolites in BP2-treated larvae. Using E2 treatment and morpholino knockdown assays, we provided strong genetic evidence that the BP2-induced behavioral disorders were associated with estrogen-dependent signaling, especially estrogen receptors 2a and 2b (esr2). Subsequently, transcriptomic profiling indicated that the activation of esr2 further inhibited the expression of LIM homeobox transcription factor 1 β a (lmx1ba), which is vital for normal neurodevelopment. Consistently, the overexpression of lmx1ba and inhibition of esr2 obviously alleviated BP2-caused neurotoxicity, uncovering a seminal role of esr2 and lmx1ba in BP2-induced neurodevelopmental toxicity. Our findings provide the first evidence in fish that BP2 can induce neurodevelopmental deficits and brain dysfunction and offer novel insights into the mechanisms of toxicity of BP2 as well as other emerging benzophenones.

In silico analysis of endocrine-disrupting potential of triclosan, bisphenol A, and their analogs and derivatives

Owning to the increasing body of evidence about the ubiquitous exposure to endocrine disruptors (EDCs), particularly bisphenol A (BPA), and associated health effects, BPA has been gradually substituted with insufficiently tested structural analogs. The unmanaged excessive use of antimicrobial agents such as triclosan (TCS) during the COVID-19 outbreak has also raised concerns about its possible interferences with hormonal functions. The similarity of BPA and estradiol, as well as TCS and non-steroidal estrogens, imply that endocrine-disrupting properties of their analogs could be predicted based on the chemical structure. Hence, this study aimed to evaluate the endocrine-disrupting potential of BPA substitutes as well as TCS derivatives and degradation/biotransformation metabolites, in comparison to BPA and TCS based on their molecular properties, computational predictions of pharmacokinetics and binding affinities to nuclear receptors. Based on the obtained results several under-researched BPA analogs exhibited higher binding affinities for nuclear receptors than BPA. Notable analogs included compounds detected in receipts (DD-70, BTUM-70, TGSA, and BisOPP-A), along with a flame retardant, BDP. The possible health hazards linked to exposure to TCS and its mono-hydroxylated metabolites were also found. Further research is needed in order to elucidate the health impacts of these compounds and promote better regulation practices.

Prenatal exposure to low doses of benzophenone-3 elicits disruption of cortical vasculature in fetuses through perturbations in Wnt/β-catenin signaling correlating with depression-like behavior in offspring mice

Benzophenone-3 (BP-3), commonly used in personal care products, is routinely detected in environmental and human matrices. Evidence delineates a correlation between gestational BP-3 exposure and emotional and social disorders in children and adolescents. However, sensitive target cells and the mode of action underlying the early responses to environmentally relevant level of BP-3 exposure remain unclear. In this study, 0.3 and 3 mg/kg of BP-3 were administered to pregnant mice. Compared with the control group, the cortical blood vessel development process manifested the highest susceptibility to BP-3 exposure using transcriptomic sequencing at embryonic day 14 (E14). Notably, the diminution in vascular density and tight junction proteins presence was observed in the fetal cortex at E14, concomitant with the suppressed transcriptional activity of genes essential to angiogenesis and barrier formation. Strikingly, the investigation revealed that BP-3 exposure impeded vascular sprouting in aortic ring explants and neuroendothelial migration, implicating the Wnt/β-catenin signaling pathway. Moreover, BP-3 exposure compromised perivascular neural stem cell differentiation. Cortical vascular injury correlated with the exhibition of depression-like behavior in four-week postnatal progeny. These insights underscore the cerebrovasculature as an early sensitive target for low doses of BP-3 exposure, fostering the development of biomarkers and the establishment of the adverse outcome pathway framework for BP-3 hazard evaluation.

Association between percutaneous absorption of benzophenone-3 and N, N-diethyl-m-toluamide among the general adult population

BACKGROUND

Multiple studies have confirmed the mutual enhancement of percutaneous permeation of benzophenone-3 (BP-3) and N,N-diethyl-m-toluamide (DEET), which are effective ingredients in sunscreen products and insect repellents, respectively. However, the association between percutaneous absorption of BP-3 and DEET in a large general adult population remains to be elucidated.

METHODS

This cross-sectional study included US adults who had available data on urinary BP-3 and two DEET metabolites, 3-(diethylcarbamoyl) benzoic acid (DCBA) and 3-(ethylcarbamoyl) benzoic acid (ECBA), from the National Health and Nutrition Examination Survey (NHANES) conducted in 2015-2016. We conducted three weighted multivariable linear regression models to investigate the potential correlation between percutaneous absorption of BP-3 and DEET, along with trend tests, smooth curve fitting, and subgroup analysis to assess the robustness of the findings.

RESULTS

Weighted multivariable linear logistic regression revealed a positive correlation between log10 BP-3 and log10 DCBA (β = 0.1678, 95 % CI: 0.0970 to 0.2386) as well as log10 ECBA (β = 0.1416, 95 % CI: 0.0707 to 0.2125), after adjusting for all covariates. After converting log10 BP-3 from a continuous variable to a categorical variable (quartiles), the trend tests showed that the results were stable (all P for trend < 0.05). Smoothed curve fitting demonstrated a linear positive correlation between log10 BP-3 and both log10 DCBA and log10 ECBA. In subgroup analyses, the positive correlation between BP-3 and DEET metabolites was more pronounced in participants who were male, middle-aged, non-Hispanic white, had a moderate PIR level and reported always or most of the time using sunscreen.

CONCLUSIONS

Our findings revealed a statistically significant linear and positive correlation between the percutaneous absorption of BP-3 and DEET in the general adult population.

Granulated rubber in playgrounds and sports fields: A potential source of atmospheric plastic-related contaminants and plastic additives after runoff events

The use of "crumb rubber" coming from recycling materials in outdoor floors like playgrounds has been a frequent practice during the last years. However, these surfaces are object of abrasion and weathering being a potential source of micro and nanoplastics (MNPLs) to the atmosphere and a potential source of human exposure to them. Our main goal has been to expose different crumb rubber materials to summer weathering effects. The released inhalable fractions were sampled for two months with passive samplers and the composition of MNPLs and plastic additives (organic and inorganic) were evaluated. The ecotoxicological effects of leached materials emulating runoff events was evaluated in freshwater micro crustacean Daphnia magna and the green algae Chlorella vulgaris. The analysis of MNPLs showed the presence of polyethylene, polypropylene, polybutadiene, polysiloxanes and polybutylene at concentrations up to 30,426 ng/m3. In the same fraction, we also identified up to 56 plastic additives, including antioxidants, pigments, copolymers, flame retardants, fungicides, lubricants, plasticizers, UV filters and metal ions. Finally, runoff ecotoxicological effects on D. magna and C. vulgaris showed that leached compounds, either from virgin or aged material, would be toxicants for exposed organisms although at concentrations much higher than those expected to be released to the media.

Benzophenone-4 inhibition in marine diatoms: Physiological and molecular perspectives

Benzophenone-4 (BP-4), a widely utilized organic ultraviolet (UV) filter, is recognized as a pseudo-persistent contaminant in aquatic environments. To elucidate the effects and mechanisms of BP-4 on marine diatoms, an investigation was conducted on the growth rate, photosynthetic pigment content, photosynthetic parameters, antioxidant enzyme activity, malondialdehyde (MDA) levels, cellular structure, and transcriptome profile of the model species, Phaeodactylum tricornutum. The results showed a pronounced inhibition of algal growth upon exposure to BP-4, with a 144 h-EC50 value of 201 mg·L-1. In addition, BP-4 exposure resulted in a significant reduction in biomass, disruption of cell membrane integrity, and increased MDA accumulation, with levels escalating 3.57-fold at 125 mg·L-1 of BP-4. In the BP-4-treated samples, 1556 differentially expressed genes (DEGs) were identified, of which 985 were upregulated and 571 were downregulated. Gene ontology and KEGG pathway enrichment analysis revealed that the carbon fixation and carbon metabolism processes in P. tricornatum were disrupted in response to BP-4 exposure, along with excessive reactive oxygen species (ROS) production. The upregulation of genes associated with photosynthetic pigment (chlorophyll and carotenoids) synthesis, phospholipid synthesis, ribosome biogenesis, and translation-related pathways may be regarded as a component of P. tricornatum's tolerance mechanism towards BP-4. These results provide preliminary insights into the toxicity and tolerance mechanisms of BP-4 on P. tricornatum. They will contribute to a better understanding of the ecotoxicological impacts of BP-4 on the marine ecosystem and provide valuable information for elimination of BP-4 in aquatic environment by bioremediation.

Estrogen receptor/androgen receptor transcriptional activation of benzophenone derivatives and integrated approaches to testing and assessment (IATA) for estrogenic effects

Estrogen receptor (ER) and androgen receptor (AR) transactivation assays for the benzophenone compounds (BPs) were performed using hERα-HeLa-9903 cells for ER and MMTV/22Rv1_GR-KO cells for AR. Results showed that some BPs, such as BP-1, BP-2, 4OH-BP, 4DHB, and 4-MBP, showed agonistic activity on ER with a higher RPCmax than 1 nM 17-β estradiol. The other BPs (BP, BP-3, BP-6, BP-7, and BP-8) showed low RPCmax in accordance with the OECD Test guideline (TG) 455 criteria, with BP-4 as the only ER-negative. However, the potency of the BPs was at least 1000 times less than the reference chemical, 17-β-estradiol. None of the BPs exhibited agonistic activity on AR except BP-2 which showed a small increase in activity. For further evaluation of the estrogenic effect of BPs based on the integrated approaches to testing and assessment (IATA) approach, existing data on ER binding, steroidogenesis, MCF-7 cell proliferation, and in vivo uterotrophic assays were collected and evaluated. There seemed to be a close association between the in vitro data on BPs, especially ER transcriptional activity, and the in vivo results of increased uterine weight. This case study implied that integrated approaches using in vitro data can be a useful tool for the prediction of in vivo data for estrogenic effects, without the need for additional animal toxicity tests.

Migration of Chemical Compounds from Packaging Materials into Packaged Foods: Interaction, Mechanism, Assessment, and Regulations

The migration of chemical compounds from packaging polymers to food presents a multifaceted challenge with implications for food safety and public health. This review explores the interaction between packaging materials and food products, focusing on permeation, migration, and sorption processes. The different migration mechanisms of contact migration, gas phase migration, penetration migration, set-off migration, and condensation/distillation migration have been discussed comprehensively. The major migrating compounds are plasticizers, nanoparticles, antioxidants, light stabilizers, thermal stabilizers, monomers, oligomers, printing inks, and adhesives, posing potential health risks due to their association with endocrine disruption and carcinogenic effects. Advanced analytical methods help in the monitoring of migrated compounds, facilitating compliance with regulatory standards. Regulatory agencies enforce guidelines to limit migration, prompting the development of barrier coatings and safer packaging alternatives. Furthermore, there is a need to decipher the migration mechanism for mitigating it along with advancements in analytical techniques for monitoring the migration of compounds.

Relationship between the use of hair products and urine benzophenone-3: the Korean National Environmental Health Survey (KoNEHS) cycle 4

Background

Benzophenone-3 is a type of ketone with 2 benzene rings attached to a carbonyl group (C=O) and one benzene ring attached to a hydroxyl group (-OH). As an endocrine-disrupting chemical, benzophenone-3 is known to be associated with reproductive, developmental, thyroid, and endocrine toxicities. Benzophenone-3 is commonly used in hair products, cosmetics, and ultraviolet (UV) filters because of its characteristic property to absorb UV light. This study aims to investigate the association between the use of hair products and urine benzophenone-3 using the data from the Korean National Environmental Health Survey (KoNEHS) cycle 4 (2018-2020), which represents the Korean population.

Methods

Using the KoNEHS cycle 4 survey, the data of 3,796 adults aged ≥ 19 years were analyzed. Based on the 75th percentile concentration of urine benzophenone-3, the participants were divided into the low- and high-concentration groups. Chi-square test was conducted to analyze the association of urine benzophenone-3 with distribution of general characteristics, use of personal care products, consumption of marine foods, and use of plastic products as the variable. Logistic regression analysis was conducted to calculate odds ratios (ORs) for the high-concentration group of urine benzophenone-3 based on the use of hair products.

Results

Women with < 6 times or ≥ 6 times of hair product usage had significantly higher adjusted ORs compared to those who did not use hair products. The calculated ORs were 1.24 (95% confidence interval [CI]: 1.12-1.38) for women with < 6 times of usage and 1.54 (95% CI: 1.33-1.79) for women with ≥ 6 times of usage.

Conclusions

This study revealed the association between the use of hair products and the concentration of urine benzophenone-3 in the general Korean population.

Association of Phenols, Parabens, and Their Mixture with Maternal Blood Pressure Measurements in the PROTECT Cohort

BACKGROUND

Phenols and parabens are two classes of high production volume chemicals that are used widely in consumer and personal care products and have been associated with reproductive harm and pregnancy complications, such as preeclampsia and gestational diabetes. However, studies examining their influence on maternal blood pressure and gestational hypertension are limited.

OBJECTIVES

We investigated associations between individual phenols, parabens, and their mixture on maternal blood pressure measurements, including systolic and diastolic blood pressure (SBP and DBP) and hypertension during pregnancy (defined as stage 1 or 2 hypertension), among N = 1,433 Puerto Rico PROTECT study participants.

METHODS

We examined these relationships cross-sectionally at two time points during pregnancy (16-20 and 24-28 wks gestation) and longitudinally using linear mixed models (LMMs). Finally, we used quantile g-computation to examine the mixture effect on continuous (SBP, DBP) and binary (hypertension during pregnancy) blood pressure outcomes.

RESULTS

We observed a trend of higher odds of hypertension during pregnancy with exposure to multiple analytes and the overall mixture [including bisphenol A (BPA), bisphenol S (BPS), triclocarbon (TCC), triclosan (TCS), benzophenone-3 (BP-3), 2,4-dichlorophenol (2,4-DCP), 2,5-dichlorophenol (2,5-DCP), methyl paraben (M-PB), propyl paraben (P-PB), butyl paraben (B-PB), and ethyl paraben (E-PB)], especially at 24-28 wk gestation, with an adjusted mixture odds ratio ( OR ) = 1.57 (95% CI: 1.03, 2.38). Lower SBP and higher DBP were also associated with individual analytes, with results from LMMs most consistent for methyl paraben (M-PB) or propyl paraben (P-PB) and increased DBP across pregnancy [adjusted M-PB β = 0.78 (95% CI: 0.17, 1.38) and adjusted P-PB β = 0.85 (95% CI: 0.19, 1.51)] and for BPA, which was associated with decreased SBP (adjusted β = - 0.57 ; 95% CI: - 1.09 , - 0.05 ). Consistent with other literature, we also found evidence of effect modification by fetal sex, with a strong inverse association observed between the overall exposure mixture and SBP at visit 1 among participants carrying female fetuses only.

CONCLUSIONS

Our findings indicate that phenol and paraben exposure may collectively increase the risk of stage 1 or 2 hypertension during pregnancy, which has important implications for fetal and maternal health. https://doi.org/10.1289/EHP14008.

Temporal trends in exposure to parabens, benzophenones, triclosan, and triclocarban in adult females in Kyoto, Japan, from 1993 to 2016

Products used in daily life can contain chemicals such as parabens, benzophenones, triclosan, and triclocarban that have potential endocrine-disrupting effects. Little is known about the temporal trends of exposure levels to some of these chemicals in Japan. Our study assessed the intake and risk associated with exposure to commonly used chemicals. We measured the concentrations of five parabens, four benzophenones, and triclosan and triclocarban in 133 single spot urine samples. The urine samples were collected in 1993, 2000, 2003, 2009, 2011, and 2016 from healthy female residents in Kyoto, Japan. With the exception of methylparaben, ethylparaben, and butylparaben, there were no significant fluctuations in the concentrations of target chemicals over the study period; however, methylparaben, ethylparaben, and butylparaben showed temporal changes in concentrations. Methylparaben concentrations peaked in 2003 with a median value of 309 μg/g creatinine, ethylparaben concentrations peaked in 1993 with a median value of 17.3 μg/g creatinine, and butylparaben showed a decline, with the median values becoming non-detectable in 2009 and 2016. We calculated estimated daily intakes and hazard quotients for each chemical. In the analysis of total samples, 2.3% (3 samples) for butylparaben and 0.8% (1 sample) for propylparaben were found to surpass a hazard quotient of 1. Overall, 3% (n = 4) of the study participants exceeded a hazard index of 1. The potential health risks associated with exposure to butylparaben and propylparaben emphasize the need for further monitoring and research.

Microplastics and volatile organic compounds released from face masks after disinfection: Layers and materials differences

Effective disinfection methods are critical for ensuring the reusability of masks, yet these methods may inadvertently introduce health concerns associated with microplastics (MPs) and volatile organic compounds (VOCs). This study investigated the impact of ultraviolet germicidal irradiation (UVGI) and sodium hypochlorite (NaClO) bleaching on mask filter layers composed of four distinct materials. Our results revealed that UVGI induced more pronounced damage compared to bleaching, leading to the significant release of both MPs and VOCs. After UVGI treatment at conventional disinfection doses, meltblown (MB) fabrics released MPs reaching 864 ± 182 μg/g (92 ± 19 particles/g). For all filter layers, the quantity of released MPs followed the order: MB > HDPE>PU ≈ NW. These MPs were identified as degraded debris from the mask filter layers. The specific VOCs generated varied depending on the material composition. Non-woven (NW) and MB fabrics, both comprised of polypropylene, predominantly produced various branched aliphatic hydrocarbons and their derivative oxides. The cotton-like fabric, composed of high-density polyethylene, primarily emitted different linear aliphatic hydrocarbons and oxygenates. In contrast, the polyurethane filter layer of reusable masks released aromatic compounds, nitrogenous compounds, and their oxidation products. The formation of VOCs was primarily attributed to bond breakage and oxidative damage to the filter structure resulting from the disinfection process. In summary, as UVGI induced higher yields of MPs and VOCs compared to bleaching, the latter would be a safer option for mask disinfection.