Metabolites of 4-methylbenzylidene camphor (4-MBC), butylated hydroxytoluene (BHT), and tris(2-ethylhexyl) trimellitate (TOTM) in urine of children and adolescents in Germany - human biomonitoring results of the German Environmental Survey GerES V (2014-2017)

Biotransformation of oxybenzone and 3-(4-methylbenzylidene)camphor in Cunninghamella species: Potential for environmental clean-up of widely used sunscreen agents

The extensive use of organic UV filters (OUVFs) has led to these compounds being ubiquitously detected in the environment and considered a new kind of environmental pollutant. As OUVFs cannot be efficiently eliminated by conventional treatment processes, there is an urgent need to develop new innovative solutions for their removal. The present work investigates the efficacy of three Cunninghamella strains in the biodegradation of OUVFs: oxybenzone (BP-3) and 3-(4-methylbenzylidene)camphor (4-MBC). Moreover, a cytochrome P450 (CYP450) inhibition study was conducted, and Cunninghamella-processed samples in silico and in vitro toxicity were evaluated. Our results indicated the ability of Cunninghamella strains to utilize OUVFs. Among the tested Cunninghamella strains, both agents were the most efficiently removed by C. blakesleeana. These results were comparable with A. niger biodegradation capacity. In vitro studies of the fungi-processed samples confirmed no mutagenicity in the Ames test and the lack of cytotoxicity against HepG2 cell line. Moreover, Cunninghamella treatment positively influenced OUVFs SH-SY5Y neurotoxicity and ecotoxicity. After fungal treatment, BP-3 agonistic estrogenic activity was higher, whereas antagonistic androgenic effect was lower than before biotransformation. 4-MBC, after biotransformation, lost agonistic estrogenic activity, but gained antagonistic estrogenic properties. Additionally, this study confirmed the involvement of CYP450 enzymes in BP-3 and 4-MBC biotransformation, thus contributing to a better understanding of the detoxification pathways of OUVFs in fungi. In conclusion, these findings demonstrated, for the first time, that using environmental fungi Cunninghamella for the biodegradation of BP-3 and 4-MBC represents a potent approach for eliminating contaminants from the natural environment.

Reproductive toxicity and parental transmission effects of 4-methylbenzylidene camphor (4-MBC) exposure in adult zebrafish

4-methylbenzylidene camphor (4-MBC), a commonly used UV absorber, is frequently detected in aquatic environment. So far the reproductive toxicity of parental 4-MBC exposure and its effects on gonadal development in offsprings are not clear. In the present study, male and female adult F0 zebrafish were exposed to 100 nM 4-MBC for 14 consecutive days. Our data showed that 4-MBC exposure resulted in gonadal damage in the parental gonads and decreased egg production in females and sperm viability in males. In addition, exposure to 4-MBC resulted in increased levels of estradiol (E2), follicle stimulating hormone (FSH), and luteinizing hormone (LH) in females and decreased testosterone (T) in males, suggesting the estrogenic and antiandrogenic effects of 4-MBC. Parental 4-MBC exposure did not change the hatchability and mortality of the F1 generation, but caused significantly decreased heart rate and gonadal developmental retardation in 60 dpf fish by interfering with the HPG axis. Therefore, 4-MBC exposure to adult zebrafish caused gonadal damage and reduced reproductive performance in the parental generation, which was sex-dependent and caused intergenerational toxicity to the F1 generation. The present study provides new insights into the ecological risks of 4-MBC and its potential contribution to adverse reproductive outcomes in humans.

Assessing the exposure to the UV filter DHHB in urine samples from the German Environmental Specimen Bank (2000-2021): Evaluating the impact of a potential impurity of di-n-hexyl phthalate in DHHB

Human biomonitoring (HBM) has become a crucial tool for assessing exposure to emerging chemicals. We analyzed 250 24-h urine samples from the German Environmental Specimen Bank (ESB), collected between 2000 and 2021, for exposure to diethylamino hydroxybenzoyl hexyl benzoate (DHHB), a UV filter increasingly used in sunscreens. Three major metabolites were examined: 2-(4-diethylamino)-, 2-(4-ethylamino)-, and 2-(4-amino)-2-hydroxybenzoyl)benzoic acid (DHB, EHB, AHB), with detection rates of 18°%, 13°%, and 87°%, respectively. While EHB and DHB were specific to DHHB, AHB suggested other exposure sources, making it unreliable for assessing DHHB exposure. DHB and EHB were first detected in 2012, with increased detection rates thereafter. The median daily intake of 37 ng/kg bw/d was much lower than the derived no-effect level of 2900 mg/kg bw/d, indicating low risk from DHHB exposure. However, since the analyzed ESB samples were collected in winter, they likely reflect exposure from other products and the environment rather than sunscreen-related exposure. Recently, concerns have emerged regarding the DHHB impurity di-n-hexylphthalate (DnHexP), a reproductive toxicant not authorized in the EU. Retrospective analysis of oral DHHB dosing experiments indeed revealed impurity related dose-dependent excretion of DnHexP metabolites (MnHexP, oxidized 5-OH-MnHexP, and 5-oxo-MnHexP). Due to uncertainties in dose allocation, only a rough excretion fraction of 45°% for MnHexP was derived. Our findings suggest that the DHHB impurity DnHexP may contribute to DnHexP exposure in sunscreen users applying products with contaminated DHHB. Given DnHexP's toxicity, this warrants re-assessment of DHHB's safety in cosmetics and enhanced surveillance of both DHHB and DnHexP in HBM studies.

The influence of 2,6-Di-tert-butyl-p-cresol stress on the microalga Phaeodactylum tricornutum and phycosphere bacteria community

The emerging contaminant 2, 6-di-tert-butyl-p-cresol (BHT) is a kind of synthetic phenolic antioxidant and can pose negative effects on the aquatic organism. However, the mechanism of phycosphere bacteria coordinating with microalgae in response to BHT stress remains poorly understood. Herein, the effect of BHT on the microalgae Phaeodactylum tricornutum was comprehensively analyzed. BHT exposure led to a dose-dependent inhibition of P. tricornutum growth and the photosynthetic pigment biosynthesis. BHT also led to an increase in the content of malondialdehyde, therefore microalgae responded to the oxidative stress by enhancing activities of antioxidant enzymes, including superoxide dismutase, catalase and peroxidase, to eliminate excess reactive oxygen species in the cells. Furthermore, transcriptome analysis revealed that genes related to photosynthesis, TCA cycle, oxidative phosphorylation, and indole-3-acetic acid (IAA) synthesis were up-regulated in response to BHT stress, which are crucial for the microalgae's adaptation to stresses. In addition, high-throughput Illumina MiSeq sequencing results demonstrated a significant increase in the relative abundance of bacteria affiliated with Halomonas, Marivita and Oceanicaulis. Microbiological assays demonstrated that Halomonas can thrive by using BHT as the sole energy source and exhibit a chemotactic response to IAA. Therefore, we conclude that the increased content of IAA secreted by microalgae in the phycosphere environment promoted the enrichment of BHT-tolerant bacterium Halomonas, thereby it is helpful for environmental pressures adaptability of P. tricornutum. Overall, this study provided a comprehensive understanding of the physiological and biochemical effects of BHT on microalgae, and we highlight the potential functional significance of IAA in establishing an interaction between microalgae and algae-associated bacteria in adverse environments.

Development and validation of an analytical method for metabolites of the plasticizer tri-(2-ethylhexyl) trimellitate (TOTM) in human urine by LC-MS/MS

Tri-(2-ethylhexyl) trimellitate (TEHTM or TOTM) is an alternative plasticizer used as replacement for conventional phthalates, such as bis-(2-ethyl-hexyl) phthalate (DEHP) in plastic materials. Migration studies show a lower leaching potential from the polymer matrix, compared to DEHP. Additionally, toxicological studies showed lower negative health effects of TOTM. A sensitive bioanalytical method is necessary to further enable the exposure assessment of TOTM. In this study, we developed a quantitative method based on SPE and LC-MS/MS for analysis of ten urinary metabolites of TOTM, such as 1,4-di-(2-ethylhexyl) trimellitate (1,4-DEHTM), 2,4-di-(2-ethylhexyl) trimellitate (2,4-DEHTM), 1-mono-(2-ethylhexyl) trimellitate (1-MEHTM), 2-mono-(2-ethylhexyl) trimellitate (2-MEHTM), 1-mono-(2-ethyl-5-carboxypentyl) trimellitate (5Cx-1-MEPTM), 2-mono-(2-ethyl-5-carboxypentyl) trimellitate (5Cx-2-MEPTM), 2-mono-(2-ethyl-5-hydroxyhexyl) trimellitate (5OH-2-MEHTM), and 1-mono-(2-ethyl-5-hydroxyhexyl) trimellitate (5OH-1-MEHTM), and 1-mono-(2-carboxymethylhexyl) trimellitate (2Cx-MMHTM). The method was validated according to the current 'Bioanalytical Method Validation guidelines' from European Medicines Agency (EMA). All validation criteria were successfully passed, except for 2Cx-MMHTM and 5Cx-2-MEPTM, which were discarded due to unsatisfactory validation results and low clinical relevance. Additionally, 1,4- and 2,4-DEHTM were successfully validated as a sum of two isomers. The validated method was applied to a pilot set of 30 urine samples from newborn patients. Significant higher urinary concentrations were found for 5Cx-1-MEPTM, 5OH-1-MEHTM, 5OH-2-MEHTM, 5oxo-1-MEHTM and 2-MEHTM in prematurely born babies from the neonatal intensive care unit (NICU) compared to term-born newborns. The current study expanded the range of analytes to eight TOTM metabolites which can be simultaneously analysed in urine samples. It also showed its clinical importance by analysing urine samples from newborns admitted to the NICU.

Occurrence, Characteristics, and Mixed Reproductive Exposure Risk Assessment of Traditional Phthalates and Their Novel Alternatives in Campus Indoor Dust

Phthalates (PAEs) constitute the primary components of indoor dust pollutants and significantly impact human reproductive health. However, research on novel alternatives to PAEs and the risk assessment of mixed exposure has remained relatively sparse. In this study, 193 indoor dust samples were collected in 2022 from various campus locations, including classrooms, canteens, dormitories, offices, and laboratories. Forty-four traditional PAEs and their alternatives were identified, with concentrations ranging from 0.44 to 91.5 μg/g. Di(2-ethylhexyl) phthalate (DEHP) and dioctyl terephthalate (DEHTH) were the predominant compounds, with mean concentrations of 86.3 and 59.2 μg/g, respectively. The ingestion pathway was the principal route of exposure, with dormitories identified as the primary exposure sites. The mixed reproductive toxicity equivalent factor (TEFmix) of PAEs and their alternatives was developed using a quantitative structure-activity relationship (QSAR) model in conjunction with machine learning algorithms. The TEFmix was found to be lower than the sum of individual PAEs, potentially due to the antagonistic effects of PAE monomers on reproductive health. Under high-exposure scenarios, the TEFmix of PAEs in canteen dust was determined to be 0.245, surpassing values observed in other environments. Females exhibited a higher risk, with dormitories presenting a greater exposure risk than those in other indoor locations. This study provided essential data to inform regulatory measures aimed at mitigating the impact of PAEs and their alternatives in indoor dust on human reproductive health.

Chemical Prioritisation for Human Biomonitoring in Ireland: A Synergy of Global Frameworks and Local Perspectives

Human biomonitoring (HBM) is a critical scientific tool for assessing human exposure by quantifying chemicals and their metabolites in biological specimens such as blood and urine. This approach provides a comprehensive and accurate evaluation of internal exposures from diverse sources and exposure routes. In Ireland, establishing a national HBM programme requires a systematic chemical prioritisation process that aligns global frameworks with local public perceptions. This study integrates insights from international initiatives such as the European Joint Programme Human Biomonitoring for Europe (HBM4EU) and the Partnership for the Assessment of Risks from Chemicals (PARC)-along with HBM programmes from EU countries (Germany, France, Belgium, Norway, Slovenia, Czech Republic, and Sweden) and non-EU countries (US, Canada, South Korea, China, and New Zealand). In addition, a national survey was conducted to capture the perceptions of people in Ireland regarding chemicals of concern to develop a comprehensive priority list of chemicals and biomarkers. The broader chemical groups identified include heavy metals (lead, cadmium, mercury, arsenic, and chromium VI), plasticisers (phthalates), bisphenols, pesticides, flame retardants, PFASs (per- and polyfluoroalkyl substances), PAHs (polycyclic aromatic hydrocarbons), POPs (persistent organic compounds), VOCs (volatile organic compounds), and UV (ultraviolet) filters. This integrated, participatory approach provides a roadmap for a robust, adaptable chemical list that supports evidence-based policy decisions in HBM in Ireland and enhances public health outcomes.

Nationwide human biomonitoring strategy in Korea: Prioritization of novel contaminants using GC/TOF-MS with suspect and non-target screening

According to global regulations on hazardous chemicals, numerous alternatives have been manufactured and used in various consumer products. Suspect and non-target analyses are advanced analytical techniques used for identifying novel contaminants. In the present study, suspect and non-target analytical approaches using a gas chromatography coupled to a time-of-flight mass spectrometer were applied to identify novel contaminants in 40 pooled serum samples from a sub-population (n = 400) of the 2015-2017 national biomonitoring program. Suspect screening analysis was performed using an in-house library based on retention times and quantifier and qualifier ions for 222 contaminants, including persistent organic pollutants and emerging contaminants. Non-target analysis was performed by matching deconvoluted mass spectra to the spectral library from the National Institute of Standards and Technology. The suspect screening analysis identified organochlorinated pesticides, organophosphate esters, phthalate esters, and alternative plasticizers. Among the 68 compounds identified in the non-target analysis, siloxanes, novel organophosphate esters, and UV ink photoinitiators were considered candidates for future inclusion in the biomonitoring program based upon significant human exposure. Our findings demonstrate the feasibility of suspect and non-target analysis to identify novel contaminants to prioritize for inclusion within a national human biomonitoring program.

Integrated proteome and pangenome analysis revealed the variation of microalga Isochrysis galbana and associated bacterial community to 2,6-Di-tert-butyl-p-cresol (BHT) stress

The phenolic antioxidant 2,6-Di-tert-butyl-p-cresol (BHT) has been detected in various environments and is considered a potential threat to aquatic organisms. Algal-bacterial interactions are crucial for maintaining ecosystem balance and elemental cycling, but their response to BHT remains to be investigated. This study analyzed the physiological and biochemical responses of the microalga Isochrysis galbana and the changes of associated bacterial communities under different concentrations of BHT stress. Results showed that the biomass of I. galbana exhibited a decreasing trend with increasing BHT concentrations up to 40 mg/L. The reduction in chlorophyll, carotenoid, and soluble protein content of microalgal cells was also observed under BHT stress. The production of malondialdehyde and the activities of superoxide dismutase, peroxidase, and catalase were further determined. Scanning electron microscopy analysis revealed that BHT caused surface rupture of the algal cells and loss of intracellular nutrients. Proteomic analysis demonstrated the upregulation of photosynthesis and citric acid cycle pathways as a response to BHT stress. Additionally, BHT significantly increased the relative abundance of specific bacteria in the phycosphere, including Marivita, Halomonas, Marinobacter, and Alteromonas. Further experiments confirmed that these bacteria had the ability to utilize BHT as the sole carbon resource for growth, and genes related to the degradation of phenolic compounds were detected through pangenome analysis.

Global Environmental and Toxicological Data of Emerging Plasticizers: Current Knowledge, Regrettable Substitution Dilemma, Green Solution and Future Perspectives

The global plasticizer market is projected to increase from $17 billion in 2022 to $22.5 billion in 2027. Various emerging/alternative plasticizers entered the market following the ban on several phthalate plasticizers because of their harmful effects. However, there is limited data (especially peer-reviewed) on emerging plasticizers' toxicity and environmental impact. This review compiles available data on toxicity, exposure, environmental effects, and safe production of emerging plasticizers. It identifies gaps in scientific research and provides evidence that emerging plasticizers are potential cases of regrettable substitution. Several alternative plasticizers, such as acetyl tributyl citrate (ATBC), diisononyl cyclohexane-1,2 dicarboxylate (DINCH), tris-2-ethylhexyl phosphate (TEHP), tricresyl phosphate (TCP), tris-2-ethylhexyl phosphate (TPHP), bis-2-ethylhexyl terephthalate (DEHT), and tris-2-ethylhexyl trimellitate (TOTM), show potential as endocrine disrupting properties and other toxic characteristics. Some chemicals like bis-2-ethylhexyl adipate (DEHA), diisobutyl adipate (DIBA), ATBC, DINCH, bis-2-ethylhexyl sebacate (DOS), diethylene glycol dibenzoate (DEGDB), DEHT, and phosphate esters showed the potential to cause toxicity in aquatic species. Plus, there is great lack of information on compounds like diisononyl adipate (DINA), dibutyl adipate (DBA), diisodecyl adipate (DIDA), dipropylene glycol dibenzoate (DPGDB), dibutyl sebacate (DBS), alkylsulfonic phenyl ester (ASE), trimethyl pentanyl diisobutyrate (TXIB), DEGDB and bis-2-ethylhexyl sebacate (DOS). Some compounds like epoxidized soybean oil (ESBO), castor-oil-mono-hydrogenated acetate (COMGHA), and glycerin triacetate (GTA) are potentially safer or less toxic. Alternative plasticizers such as adipates (LogKow 4.3-10.1), cyclohexane dicarboxylic acids (LogKow 10), phosphate esters (LogKow 2.7-9.5), sebacates (LogKow 6.3-10.1), terephthalates (LogKow 8.4), and vegetable oil derivatives (LogKow 6.4-14.8) have logKow values that are comparable to phthalate plasticizers (LogKow 7.5-10.4), indicating potential bioaccumulation and health consequences. Field studies have demonstrated that phosphate esters can undergo bioaccumulation and biomagnification, but there is a lack of bioaccumulation studies for other compounds. We also discuss the metabolism of emerging plasticizers, though data is limited. Our article highlights that numerous alternative compounds display potential health and ecological risks, indicating they might not be suitable substitutes for legacy plasticizers. There is also a lack of scientific data on most emerging plasticizers. This way, we call for increased research and timely regulatory action to prevent global contamination and health risks. Finally, this study presents a scientifically robust protocol to avoid harmful substitutions and ensure the production of safer chemicals.

Endocrine Disruptors and Metabolic Changes: Impact on Puberty Control

OBJECTIVE

This study aims to explore the significant impact of environmental chemicals on disease development, focusing on their role in developing metabolic and endocrine diseases. The objective is to understand how these chemicals contribute to the increasing prevalence of precocious puberty, considering various factors, including epigenetic changes, lifestyle, and emotional disturbances.

METHODS

The study employs a comprehensive review of descriptive observational studies in both human and animal models to identify a degree of causality between exposure to environmental chemicals and disease development, specifically focusing on endocrine disruption. Due to ethical constraints, direct causation studies in human subjects are not feasible; therefore, the research relies on accumulated observational data.

RESULTS

Puberty is a crucial life period with marked physiological and psychological changes. The age at which sexual characteristics develop is changing in many regions. The findings indicate a correlation between exposure to endocrine-disrupting chemicals and the early onset of puberty. These chemicals have been shown to interfere with normal hormonal processes, particularly during critical developmental stages such as adolescence. The research also highlights the interaction of these chemical exposures with other factors, including nutritional history, social and lifestyle changes, and emotional stress, which together contribute to the prevalence of precocious puberty.

CONCLUSION

Environmental chemicals significantly contribute to the development of certain metabolic and endocrine diseases, particularly in the rising incidence of precocious puberty. Although the evidence is mainly observational, it adequately justifies regulatory actions to reduce exposure risks. Furthermore, these findings highlight the urgent need for more research on the epigenetic effects of these chemicals and their wider impact on human health, especially during vital developmental periods.

Bioconcentration, biotransformation, and transcriptomic impact of the UV-filter 4-MBC in the manila clam Ruditapes philippinarum

Ultraviolet filters (UV-filters) are compounds extensively used in personal care products. These compounds are produced at increasing rates and discharged into marine ecosystems in unknown quantities and with no regulation, making them emerging contaminants. Among those, the UV-filter 4-Methylbenzylidene camphor (4-MBC) is used in a variety of personal care products such as sunscreens, soaps, or lipsticks. This high consumption has resulted in its presence in various environmental matrices at in concentrations ranging from ng to μg L-1. Very little is known, however, about the possible adverse effects in exposed non-target organisms. Our study presents novel data on the bioconcentration, toxicokinetics, and molecular effects of 4-MBC in a marine bivalve species of commercial interest, Ruditapes philippinarum (Manila clam). Organisms were exposed at two different concentrations (1.34 and 10.79 μg L-1) of 4-MBC for 7 days, followed by a 3-day depuration period (clean sea waters). Bioconcentration factors (BCF) were 3562 and 2229 L kg-1 for the low and high exposure concentrations, respectively, making this pollutant bioaccumulative according to REACH criteria. Up to six 4-MBC biotransformation products (BTPs)were identified, 2 of them for the first time. Transcriptomic analysis revealed between 658 and 1310 differently expressed genes (DEGs) after 4-MBC exposure. Functional and enrichment analysis of the DEGs showed the activation of the detoxification pathway to metabolize and excrete the bioconcentrated 4-MBC, which also involved energy depletion and caused an impact on the metabolism of carbohydrates and lipids and in the oxidative phosphorylation pathways. Oxidative stress and immune response were also evidenced through the activation of cathepsins and the complement system. Such elucidation of the mode of action of a ubiquitous pollutant such as 4-MBC at the molecular level is valuable both from an environmental point of view and for the sustainable production of Manila clam, one of the most cultivated mollusk species worldwide.

Elucidating the effect of different processing methods on the sensory quality of chestnuts based on multi-scale molecular sensory science

Chestnuts are known for their unique flavor and nutritional value. However, the flavor changes in chestnuts after processing remain unclear. Multi-intelligent sensory technologies and headspace solid-phase microextraction-arrow gas chromatography-mass spectrometry (HS-SPME-Arrow-GC-MS) combined with multivariate statistical analysis were applied to evaluate the effect of packaging and heat sterilization procedures on the sensory quality of chestnuts. The results showed that the significant variations (p < 0.05) between the different chestnut processing methods were revealed via the electronic eye (E-eye), electronic nose (E-nose), and electronic tongue (E-tongue). The packaging had a more significant influence on the sensory quality of the chestnuts than heat sterilization procedures. HS-SPME-Arrow-GC-MS identified 83 volatile compounds. The processed chestnuts exhibited higher aldehyde, ester, and alkene concentrations, while N2 packaging was more favorable to flavor elicitation and retention. Therefore, combining intelligent sensory techniques with GC-MS can rapidly determine the chestnut quality and guide industrial production.

Assessment of the plasticizer exposure of hospital workers regularly handling medical devices: A pilot study

Plastic medical devices, e.g. infusion sets, blood bags or tubing material, that are used manifold in the medical treatment of hospital patients, usually contain considerable amounts of plasticizers. Whereas several studies showed highly elevated inner plasticizer levels of patients treated with plasticized medical devices, little is known about the exposure situation of hospital staff. The present pilot study aimed to evaluate the urinary plasticizer metabolite levels of selected hospital workers of the blood bank (medical technical assistants, MTA) and of perfusionists that are regularly handling plasticized medical devices in order to estimate the work-related amount of the inner individual plasticizer exposure. The study subjects were asked to collect pre- and post-shift spot urine samples over the course of a working week, that were subsequently analyzed for selected urinary metabolites of the plasticizers DEHP, DINCH, DEHTP and TEHTM. Although the observed differences were rather low, a differentiated approach revealed a perceptible impact of the respective workplace environment on the individual urinary plasticizer metabolite levels. Thus, the group of blood bank MTA showed significantly elevated increment levels of urinary DEHP and DINCH metabolites, while the group of perfusionists, showed a considerable higher detection frequency of the main urinary TEHTM metabolite. All in all, however, it can be cautiously concluded by the results of the presented pilot study that a regular handling of plasticized medical devices by hospital employees (via inhalation or dermal contact) contributes demonstrably but yet only marginally to the individual internal plasticizer exposure.

The plastic health map: A systematic evidence map of human health studies on plastic-associated chemicals

BACKGROUND

The global production and use of plastic materials has increased dramatically since the 1960s and there is increasing evidence of human health impacts related to exposure to plastic-associated chemicals. There is, however, no comprehensive, regulatory, post-market monitoring for human health effects of plastic-associated chemicals or particles and it is unclear how many of these have been investigated for effects in humans, and therefore what the knowledge gaps are.

OBJECTIVE

To create a systematic evidence map of peer-reviewed human studies investigating the potential effects of exposure to plastic-associated particles/chemicals on health to identify research gaps and provide recommendations for future research and regulation policy.

METHODS

Medline and Embase databases were used to identify peer-reviewed primary human studies published in English from Jan 1960 - Jan 2022 that investigated relationships between exposures to included plastic-associated particles/chemicals measured and detected in bio-samples and human health outcomes. Plastic-associated particles/chemicals included are: micro and nanoplastics, due to their widespread occurrence and potential for human exposure; polymers, the main building blocks of plastic; plasticizers and flame retardants, the two most common types of plastic additives with the highest concentration ranges in plastic materials; and bisphenols and per- or polyfluoroalkyl substances, two chemical classes of known health concern that are common in plastics. We extracted metadata on the population and study characteristics (country, intergenerational, sex, age, general/special exposure risk status, study design), exposure (plastic-associated particle/chemical, multiple exposures), and health outcome measures (biochemical, physiological, and/or clinical), from which we produced the interactive database 'Plastic Health Map' and a narrative summary.

RESULTS

We identified 100,949 unique articles, of which 3,587 met our inclusion criteria and were used to create a systematic evidence map. The Plastic Health Map with extracted metadata from included studies are freely available at https://osf.io/fhw7d/ and summary tables, plots and overall observations are included in this report.

CONCLUSIONS

We present the first evidence map compiling human health research on a wide range of plastic-associated chemicals from several different chemical classes, in order to provide stakeholders, including researchers, regulators, and concerned individuals, with an efficient way to access published literature on the matter and determine knowledge gaps. We also provide examples of data clusters to facilitate systematic reviews and research gaps to help direct future research efforts. Extensive gaps are identified in the breadth of populations, exposures and outcomes addressed in studies of potential human health effects of plastic-associated chemicals. No studies of the human health effects of micro and/or nanoplastics were found, and no studies were found for 26/1,202 additives included in our search that are of known hazard concern and confirmed to be in active production. Few studies have addressed recent "substitution" chemicals for restricted additives such as organophosphate flame retardants, phthalate substitutes, and bisphenol analogues. We call for a paradigm shift in chemical regulation whereby new plastic chemicals are rigorously tested for safety before being introduced in consumer products, with ongoing post-introduction biomonitoring of their levels in humans and health effects throughout individuals' life span, including in old age and across generations.

Co-occurrence of phthalate and non-phthalate plasticizers in dust and hand wipes: A comparison of levels across various sources

E-waste dismantlers' occupational exposure to plasticizers, particularly non-phthalate (NPAE) plasticizers, is poorly understood. This study monitored 11 phthalates (PAEs) and 16 NPAEs in dust and hand wipe samples from Central China e-waste workplace and ordinary homes. Concentrations of plasticizers in dust from e-waste dismantling workshops (median: 217 μg/g) were significantly lower than that from ordinary homes (462 μg/g; p < 0.01), however, the trend was similar but not significant in hand wipes from these two scenarios (50.2 vs. 72.3 μg/m2; p = 0.139). PAEs were still the dominant plasticizers, which is, on average, 5.46 and 3.58-fold higher than NPAEs. In all samples, di-(2ethylhexyl) phthalate (65.4%) and tri-octyl trimellitate (44.9%) were the most common PAE and NPAE plasticizers. Increasing dust concentrations of di-iso-nonyl ester 1,2-cyclohexane dicarboxylic acid, citrates and sebacates were significantly associated with their levels in worker's hand wipe, by contrast, this trend was not found in general population. Dust ingestion was the main channel, followed by hand-to-mouth contact, all participants' daily plasticizer intakes (median: 154 ng/kg bw/day) are within safety limits. Our work highlights knowledge gaps about co-exposure to PAEs and NPAEs by multiple pathways in occupational e-waste workers, which could provide baseline data in the future.

A revised concept for deriving reference values for internal exposures to chemical substances and its application to population-representative biomonitoring data in German children and adolescents 2014-2017 (GerES V)

HBM reference values, in contrast to toxicologically derived values, are statistically derived values that provide information on the exposure of the population. The exceedance frequency (if applicable for individual population groups) is often a first assessment standard for the local exposure situation for municipalities. More than 25 years have passed since the German Human Biomonitoring Commission (HBMC) formulated the first recommendations for the derivation of population-based reference values (HBM reference values, RV95) for substance concentrations based on HBM studies. A fundamental revision is timely, for several reasons. There have been considerable advances in relevant statistical methods, which meant that previously time-consuming and inaccessible procedures and calculations are now widely available. Furthermore, not all steps for the derivation of HBM reference values were clearly elaborated in the first recommendations. With this revision we intended to achieve a rigorous standardization of the entire process of deriving HBM reference values, also to realise a higher degree of transparency. In accordance with established international practice, it is recommended to use the 95th percentile of the reference distribution as the HBM reference value. To this end, the empirical 95th percentile of a suitable sample should be rounded, ensuring that the rounded value is within the two-sided 95% confidence interval of the percentile. All estimates should be based on distribution-free methods, and the confidence interval should be estimated using a bootstrap approach, if possible, according to the BCa ("bias-corrected and accelerated bootstrap"). A minimum sample size of 80 observations is considered necessary. The entire procedure ensures that the derived HBM reference value is robust against at least two extreme values and can also be used for underlying mixed distributions. If it is known in advance that certain subgroups (different age groups, smokers, etc.) show differing internal exposures, it is recommended that group-specific HBM reference values should be derived. Especially when the sample sizes for individual subgroups are too small, individual datasets with potential outliers can be excluded in advance to homogenize the reference value population. In the second part, new HBM reference values based on data of the German Environmental Survey for Children and Adolescents (GerES V, 2014-2017) were derived in accordance with the revised recommendations. The GerES V is the most recent population-representative monitoring of human exposure to pollutants in Germany on children and adolescents aged 3-17 years (N = 2294). RV95 for GerES V are reported for four subgroups (males/females and 3-11/12-17 years) for 108 different substances including phthalates and alternative plasticisers, metals, organochlorine pesticides, polychlorinated biphenyls (PCB), per- and polyfluoroalkyl substances (PFAS), parabens, aprotic solvents, chlorophenols, polycyclic aromatic hydrocarbons (PAH) and UV filter, in total 135 biomarkers. Algorithms implemented in R were used for the statistics and the determination of the HBM reference values. To facilitate a quality control of the study data, the corresponding R source code is given, together with graphical representations of results. The HBM reference values listed in this article replace earlier RV95 values derived by the HBMC for children and adolescents from data of precedent GerES studies (e.g. published in Apel et al., 2017).

A time trend of urinary 4-methylbenzylidene camphor metabolites in young adults from Germany

4-methylbenzylidene camphor (4-MBC) is used as a UV-B filter in cosmetics. Two oxidized metabolites of 4-MBC - 3-(4-carboxybenzylidene)camphor (cx-MBC) and 3-(4-carboxybenzylidene)-6-hydroxycamphor (cx-MBC-OH) - were analyzed in 250 24-h urine samples from young adults in Germany. The samples were from the German Environmental Specimen Bank (ESB) and represented exposure in the years 1995, 2005, 2010, 2015 and 2019. A UHPLC-MS/MS method enabled the sensitive determination of both metabolites, with limits of quantification at 0.15 μg L^-1 (cx-MBC) and 0.30 μg L^-1 (cx-MBC-OH), respectively. A temporal trend of the internal exposure to 4-MBC was clearly noticeable. The metabolite cx-MBC was frequently quantifiable at the beginning of the period: in 70% of the samples in 1995, and 56% in 2005. After 2005, urinary concentrations and detection rates of cx-MBC dropped to reach very low levels. In 2015 and 2019, the detection rate was only 2% and 0%, respectively. A similar trend was observed for cx-MBC-OH, though overall, this metabolite was detected less often and at lower concentration levels than cx-MBC. Nowadays, measurable levels of urinary 4-MBC metabolites are an extremely rare occurrence in Germany. These trends are consistent with the history of 4-MBC use by the cosmetic industry. The highest measured individual concentration of 16.20 μg L^-1 (in a sample of the year 2005) was still more than 30 times below the health-based guidance value (HBM-I). An investigation of the ratios between both metabolites uncovered several features of the 4-MBC metabolism which have been essentially overlooked until now. In particular, stereochemical aspects should be explored in future studies. As urine was collected in autumn/winter in Northwestern Germany, the 4-MBC metabolites measured probably do not arise from sunscreen products in a narrow sense. They rather may reveal the use of other skin care products containing 4-MBC for UV protection as an added feature.

2,4-di-tert-butylphenol exposure impairs osteogenic differentiation

2,4-di-tert-butylphenol (2,4-DTBP) is a synthetic antioxidant used in polyethylene crosspolymer (PEX) water distribution pipes and food-related plastics. 2,4-DTBP can leach from plastic materials and has been found in breast milk, cord blood, and placental tissue, giving rise to the concern that this compound may interfere with fetal development. The objective of this study is to assess the impacts of 2,4-DTBP on cellular differentiation. Human induced pluripotent stem (HiPS) cells were differentiated into osteoblasts or myoblasts over 40 days, and analyzed for markers of somite, dermomyotome, sclerotome, myoblast, and osteoblast development. When cultured as stem cells, 2,4-DTBP did not alter cell viability and expression of markers (NANOG, OCT4). However, upon differentiation into somite-like cells, 2,4-DTBP had reduced levels of MEOX1 and TBX6 transcripts, while NANOG and OCT4 were in turn upregulated in a dose-dependent manner. At the sclerotome-like stage, PAX9 mRNA decreased by 2-fold in the 0.5 μM and 1.0 μM 2,4-DTBP exposure groups. After 40 days of differentiation into an osteoblast-like lineage, exposure to 2,4-DTBP significantly reduced expression of the osteogenesis transcripts RUNX2 and OSX in a dose-dependent manner. Further, Alizarin Red staining of calcium deposits was decreased in the 0.5 μM and 1.0 μM treatment groups. In contrast, myogenesis was not affected by 2,4-DTBP exposure. Interestingly, KEAP1 expression was significantly increased in the sclerotomal-like cells, but decreased in the dermomytomal-like cells, which may suggest a mechanism of action. Overall, this study shows that 2,4-DTBP can delay key processes during sclerotome and osteoblast development, leading to a potential for bone developmental issues in exposed individuals.

Monitoring the exposure to ethoxyquin between 2000 and 2021 in urine samples from the German Environmental Specimen Bank

Human Biomonitoring (HBM) of emerging chemicals gained increasing attention within the EU in recent years. After evaluating the metabolism, we established a new HBM method for ethoxyquin (EQ), a feed additive, which was banned in 2017 due to concerns regarding the possible exposure of the general population to it and its highly toxic precursor p-phenetidine. The method was applied to 250 urine samples from the Environmental Specimen Bank collected between 2000 and 2021. The major metabolite EQI was quantified in the majority of the study samples illustrating the ubiquitous exposure of the non-occupationally exposed population. A rather constant exposure was observed until 2016 with a significant decline from 2016 to 2021. This drop falls within the EU wide ban of the chemical as a feed additive from June 2017 which led to a gradual removal until its complete suspension in June 2020. The daily intake (DI) was evaluated with respect to the reported derived no-effect level (DNEL) to estimate the potential health risks from EQ exposure. The median DI of 0.0181 µg/kg bw/d corresponds to only 0.01 % of the DNEL. Even the observed maxima up to 13.1 µg/kg bw/d only accounted for 10 % of the DNEL. Nevertheless, the values suggest a general exposure with the risk of higher burden in a low fraction of the population. In regard to the EQ associated intake of the carcinogen and suspected mutagen p-phenetidine, this level of exposure cannot be evaluated as safe. The recent decrease and the broad exposure substantiate the need for future HBM campaigns in population representative studies to further investigate the observed reductions, potentially find highly exposed subgroups and clarify the impact of the ban as feed additive on EQ exposure.

Simultaneous and sensitive determination of the main metabolites of the plasticizer DEHP and its substitutes DEHTP, DINCH and TEHTM in human urine by coupling of on-line SPE, UHPLC and tandem mass spectrometry

With the prominent but toxicologically critical plasticizer di-(2-ethylhexyl) phthalate (DEHP) declining, alternative plasticizers are increasingly used leading to a continuously more diverse exposure situation of humans with multiple plasticizers. Therefore, an on-line SPE-LC-MS/MS method for the simultaneous determination of the most relevant urinary biomarkers of exposure to DEHP and the alternative plasticizers 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH), di-(2-ethylhexyl) terephthalate (DEHTP) and tri-(2-ethylhexyl) trimellitate (TEHTM) was developed. The method is characterized by a high sensitivity with limits of detection ranging from 0.006 to 0.047 μg L^-1 combined with an easy and straightforward sample preparation procedure. The wide linear working range of the method enables a reliable determination of analyte background levels in the general population as well as its potential use for monitoring studies investigating elevated plasticizer exposure settings. The method was successfully applied to urine samples from ten volunteers without occupational exposure to plasticizers revealing ubiquitous background exposure levels of the common plasticizers DEHP, DEHTP and DINCH.

In vitro and in silico approach to study the hormonal activities of the alternative plasticizer tri-(2-ethylhexyl) trimellitate TEHTM and its metabolites

Tri-(2-ethylhexyl) trimellitate (TEHTM) is a plasticizer for polyvinyl chloride (PVC) material used in medical devices. It is an alternative to di-(2-ethylhexyl) phthalate (DEHP), a well-known reprotoxic and endocrine disruptor. As plasticizers are known to easily migrate when in contact with fatty biological fluids, patient exposure to TEHTM is highly probable. However, there is currently no data on the potential endocrine-disrupting effects of its human metabolites. To evaluate the effects of TEHTM metabolites on endocrine activity, they were first synthesized and their effects on estrogen, androgen and thyroid receptors, as well as steroid synthesis, were investigated by combining in vitro and in silico approaches. Among the primary metabolites, only 4-MEHTM (4-mono-(2-ethylhexyl) trimellitate) showed agonist activities on ERs and TRs, while three diesters were TR antagonists at non-cytotoxic concentrations. These results were completed by docking experiments which specified the ER and TR isoforms involved. A mixture of 2/1-MEHTM significantly increased the estradiol level and reduced the testosterone level in H295R cell culture supernatants. The oxidized secondary metabolites of TEHTM had no effect on ER, AR, TR receptors or on steroid hormone synthesis. Among the fourteen metabolites, these data showed that two of them (4-MEHTM and 2/1-MEHTM) induced effect on hormonal activities in vitro. However, by comparing the concentrations of the primary metabolites found in human urine with the active concentrations determined in bioassays, it can be suggested that the metabolites will not be active with regard to estrogen, androgen, thyroid receptors and steroidogenesis-mediated effects.

Chemical contaminant exposures assessed using silicone wristbands among occupants in office buildings in the USA, UK, China, and India

Little is known about chemical contaminant exposures of office workers in buildings globally. Complex mixtures of harmful chemicals accumulate indoors from building materials, building maintenance, personal products, and outdoor pollution. We evaluated exposures to 99 chemicals in urban office buildings in the USA, UK, China, and India using silicone wristbands worn by 251 participants while they were at work. Here, we report concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and other brominated flame retardants (BFRs), organophosphate esters (OPEs), phthalates and phthalate alternatives, pesticides, and polycyclic aromatic hydrocarbons (PAHs). First, we found major differences in office worker chemical exposures by country, some of which can be explained by regulations and use patterns. For example, exposures to several pesticides were substantially higher in India where there were fewer restrictions and unique malaria challenges, and exposures to flame retardants tended to be higher in the USA and UK where there were historic, stringent furniture flammability standards. Higher exposures to PAHs in China and India could be due to high levels of outdoor air pollution that penetrates indoors. Second, some office workers were still exposed to legacy PCBs, PBDEs, and pesticides, even decades after bans or phase-outs. Third, we identified exposure to a contemporary PCB that is not covered under legacy PCB bans due to its presence as an unintentional byproduct in materials. Fourth, exposures to novel BFRs, OPEs, and other chemicals commonly used as substitutes to previously phased-out chemicals were ubiquitous. Fifth, some exposures were influenced by individual factors, not just countries and buildings. Phthalate exposures, for example, were related to personal care product use, country restrictions, and building materials. Overall, we found substantial country differences in chemical exposures and continued exposures to legacy phased-out chemicals and their substitutes in buildings. These findings warrant further research on the role of chemicals in office buildings on worker health.

Multi- and Transgenerational Outcomes of an Exposure to a Mixture of Endocrine-Disrupting Chemicals (EDCs) on Puberty and Maternal Behavior in the Female Rat

BACKGROUND

The effects of endocrine-disrupting chemicals (EDCs) on fertility and reproductive development represent a rising concern in modern societies. Although the neuroendocrine control of sexual maturation is a major target of EDCs, little is known about the potential role of the hypothalamus in puberty and ovulation disruption transmitted across generations.

OBJECTIVES

We hypothesized that developmental exposure to an environmentally relevant dose of EDC mixture could induce multi- and/or transgenerational alterations of sexual maturation and maternal care in female rats through epigenetic reprograming of the hypothalamus. We investigated the transmission of a disrupted reproductive phenotype via the maternal germline or via nongenomic mechanisms involving maternal care.

METHODS

Adult female Wistar rats were exposed prior to and during gestation and until the end of lactation to a mixture of the following 13 EDCs: di-n-butyl phthalate (DnBP), di(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), vinclozolin, prochloraz, procymidone, linuron, epoxynaxole, dichlorodiphenyldichloroethylene, octyl methoxynimmate, 4-methylbenzylidene camphor (4-MBC), butylparaben, and acetaminophen. Perinatally exposed offspring (F1) were mated with unexposed males to generate germ cell (F2) and transgenerationally exposed (F3 and F4) females. Sexual maturation, maternal behavior, and hypothalamic targets of exposure were studied across generations.

RESULTS

Germ cell (F2) and transgenerationally (F3) EDC-exposed females, but not F1, displayed delayed pubertal onset and altered folliculogenesis. We reported a transgenerational alteration of key hypothalamic genes controlling puberty and ovulation (Kiss1, Esr1, and Oxt), and we identified the hypothalamic polycomb group of epigenetic repressors as actors of this mechanism. Furthermore, we found a multigenerational reduction of maternal behavior (F1-F3) induced by a loss in hypothalamic dopaminergic signaling. Using a cross-fostering paradigm, we identified that the reduction in maternal phenotype was normalized in EDC-exposed pups raised by unexposed dams, but no reversal of the pubertal phenotype was achieved.

DISCUSSION

Rats developmentally exposed to an EDC mixture exhibited multi- and transgenerational disruption of sexual maturation and maternal care via hypothalamic epigenetic reprogramming. These results raise concerns about the impact of EDC mixtures on future generations. https://doi.org/10.1289/EHP8795.

"Novel" Synthetic Antioxidants in House Dust from Multiple Locations in the Asia-Pacific Region and the United States

Synthetic antioxidants represent a complex group of additive chemicals broadly used in consumer products. While traditional antioxidants such as 2,6-di-tert-butyl-4-methylphenol (BHT) have been well studied, a variety of "novel" antioxidants have emerged with extensive applications but received much less attention. Our study aimed to explore a suite of 34 emerging antioxidants in house dust from four different regions, including Guangzhou (China), Adelaide (Australia), Carbondale (Illinois), and Hanoi (Vietnam). The results revealed broad occurrence of several rarely investigated chemicals in house dust across regions, including triethylene glycol bis(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate (AO245), 2,6-di-tert-butyl-4-(dimethylamino)methylphenol (AO4703), 2,2'-thiene-2,5-diylbis(5-tert-butyl-1,3-benzoxazole) (BBOT), 1,3-diphenylguanidine (DPG), 2,4-bis(1,1-dimethylethyl)phenol (2,4DtBP), and 2,6-bis(1,1-dimethylethyl)phenol (2,6DtBP). In particular, DPG exhibited a median concentration of 5030-11 400 ng/g in house dust from the studied regions except for Hanoi (305 ng/g), generally 1 order of magnitude greater than that of BHT (890-1060 ng/g) and dominating the compositional profiles of antioxidants. Estimated intake of target antioxidants by toddlers via dust ingestion, even under the high exposure scenario, was determined to be 2-4 orders of magnitude lower than the reference doses of selected antioxidants. However, potential risks from long-term exposure to a cocktail of antioxidants under environmentally relevant concentrations merit further investigations due to insufficient knowledge on the sources, fate, and toxicokinetics of these chemicals to date.