Aging-Related Gene-Based Prognostic Model for Lung Adenocarcinoma: Insights into Tumor Microenvironment and Therapeutic Implications

Lung cancer remains the leading cause of cancer-related mortality globally, with a poor prognosis primarily due to late diagnosis and limited treatment options. This research highlights the critical demand for advanced prognostic tools by creating a model centered on aging-related genes (ARGs) to improve prediction and treatment strategies for lung adenocarcinoma (LUAD). By leveraging datasets from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), we developed a prognostic model that integrates 14 ARGs using the least absolute shrinkage and selection operator (LASSO) alongside Cox regression analyses. The model exhibited strong predictive performance, achieving area under the curve (AUC) values greater than 0.8 for one-year survival in both internal and external validation cohorts. The risk scores generated by our model were significantly correlated with critical features of the tumor microenvironment, including the presence of cancer-associated fibroblasts (CAFs) and markers of immune evasion, such as T-cell dysfunction and exclusion. Higher risk scores correlated with a more tumor-promoting microenvironment and increased immune suppression, highlighting the model's relevance in understanding LUAD progression. Additionally, XRCC6, a protein involved in DNA repair and cellular senescence, was found to be upregulated in LUAD. Functional assays demonstrated that the knockdown of XRCC6 led to decreased cell proliferation, whereas its overexpression alleviated DNA damage, highlighting its significance in tumor biology and its potential therapeutic applications. This study provides a novel ARG-based prognostic model for LUAD, offering valuable insights into tumor dynamics and the tumor microenvironment, which may guide the development of targeted therapies and improve patient outcomes.

Parabens as the double-edged sword: Understanding the benefits and potential health risks

Parabens are globally employed as important preservatives in pharmaceutical, food, and personal care products. Nonetheless, improper disposal of commercial products comprising parabens can potentially contaminate various environmental components, including the soil and water. Residues of parabens have been detected in surface water, ground water, packaged food materials, and other consumer items. Long-term exposure to parabens through numerous consumer products and contaminated water can harm human health. Paraben can modulate the hormonal and immune orchestra of the body. Recent findings have correlated paraben use with hypersensitivity, obesity, and infertility. Notably, parabens have also been detected in the samples of breast cancer patients, suggesting a potential cross-talk between parabens and carcinogenesis. Therefore, the present article aims to dissect the significance of parabens as a preservative in several consumer products and their impact of chronic exposure to human health. This review encompasses various facets of paraben, including its sources, mechanism of action at the molecular level, and sheds light on its toxicological implications on human health.

Formulating Sustainable Emulsions: Mandelic Acid and Essential Oils as Natural Preservatives

Emulsion products with natural antimicrobials are becoming increasingly popular for topical application. Mandelic Acid is interesting in cosmetics due to its potent exfoliating properties, which have driven advancements in skincare technologies. Essential oils have various properties, of which the most useful in cosmetics are those that do not cause irritation, smell pleasant, and have other beneficial properties such as antimicrobial effects. Emulsions with Mandelic Acid and essential oils from Satureja montana, Lemongrass, and Litsea cubeba were formulated and microbiologically tested for their preservative effectiveness. The effect of the treatments on skin condition was monitored by non-invasive diagnostic methods, such as hydration, transepidermal water loss, and pH value. Sensory analysis revealed that the matrix containing Mandelic Acid alone or combined with Litsea Cubeba Oil was the best-performing formulation, consistent with the compliant results of antimicrobial efficacy. The topical form of this cosmetic product has demonstrated excellent preservative activity and desirable biophysical efficacy on the skin.

Evaluation of dermal exposure to phthalates and parabens resulting from the use of hair relaxers

Hair relaxers have been suggested as a source of exposure to parabens and phthalates. However, dermally absorbed doses of these chemicals resulting from consumer use of hair relaxers have yet to be quantified, and results from epidemiological studies have consistently demonstrated that there is no increased risk for hormone-sensitive, reproductive cancers associated with use of hair relaxers among Black women. Therefore, dermal absorption of parabens and phthalates associated with hair relaxer use for several commercially available hair relaxer kits was modeled using IH SkinPerm™. The chemicals detected in the hair relaxer kits included methylparaben (MP), ethylparaben (EP), butylparaben (BP), diethyl phthalate (DEP), bis(2-ethylhexyl) phthalate (DEHP), and the phthalate substitute bis(2-ethylhexyl) adipate (DEHA). The daily absorbed dose ranges (mg/kg/day), standardized over a year of product use, were as follows: 8.64 × 10-5-0.00116 MP, 2.30 × 10-8-3.07 × 10-6 EP, 3.24 × 10-8-4.33 × 10-6 BP, 8.65 × 10-9-1.15 × 10-6 DEP, and 8.94 × 10-7-0.000119 DEHP for Kit #1; 8.44 × 10-5-0.00113 MP and 7.91 × 10-5-0.00106 DEP for Kit #2; and 2.49 × 10-6-3.33 × 10-5 MP, 1.52 × 10-8-2.03 × 10-6 EP, 3.29 × 10-9-4.39 × 10-7 DEP, and 3.11 × 10-6-4.14 × 10-5 DEHA for Kit #3. These absorbed doses were well below applicable health-based guidance values, indicating consumer exposure from product use is not expected to pose a health risk. These results provide valuable information for health risk evaluations for hair relaxer use.

A sustainable and innovative method to determine parabens in body creams for exposure and risk assessment

Methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP) are among the most widely used preservatives in cosmetics, drugs, and foods. These compounds have been associated with toxic effects due to the overuse of products with parabens in their formulation. The toxicity of parabens may be correlated to endocrine disruption, owing to their ability to mimic the actions of estradiol. In this paper, a simple, sustainable, robust, and innovative dispersive liquid-liquid microextraction (DLLME) technique was developed and employed to extract these xenobiotics from body cream samples, aiming to calculate the margin of safety (MoS) to assess the risk of exposure. The validated method presented suitable linearity (r > 0.99), lower limits of detection (ranging from 0.01 to 0.04 % w/w), and satisfactory precision and accuracy (ranging from 4.33 to 10.47, and from -14.25 to 13.85, respectively). Seven of the ten analysed samples presented paraben contents within the acceptable concentration according to European legislation. The MoS value obtained for PrP (37.58) suggested its reduced safety, indicating that PrP may significantly contribute to systemic exposure resulting from the use of personal care products.

Relationship between exposure to parabens and benzophenones and prostate cancer risk in the EPIC-Spain cohort

The etiology of prostate cancer is not fully elucidated. Among environmental risk factors, endocrine-disrupting chemicals (EDCs) deserve special mention, as they alter metabolic pathways involved in hormone-dependent cancers. Epidemiological evidence assessing the carcinogenicity of EDCs is scarce. The aim of this study was to analyze the relationship between exposure to parabens and benzophenones and prostate cancer risk. We conducted a case-cohort study nested within the EPIC-Spain prospective multi-center cohort. Study population comprised 1,838 sub-cohort participants and 467 non-sub-cohort prostate cancer cases. Serum concentrations of four parabens and two benzophenones were assessed at recruitment. Covariates included age, physical activity, tobacco smoking, alcohol consumption, body mass index, educational level and diabetes. Borgan II weighted Cox proportional hazard models stratified by study center were applied. Median follow-up time was 18.6 years (range = 1.0-21.7 years). Most sub-cohort participants reached primary education at most (65.5%), were overweight (57.7%) and had a low level of physical activity (51.3%). Detection percentages varied widely, being lowest for butyl-paraben (11.3%) and highest for methyl-paraben (80.7%), which also showed the highest geometric mean (0.95 ng/ml). Cases showed significantly higher concentrations of methyl-paraben (p = 0.041) and propyl-paraben (p < 0.001). In the multivariable analysis, methyl-paraben - log-transformed (HR = 1.07; 95%CI = 1.01-1.12) and categorized into tertiles (HR = 1.60 for T3; 95%CI = 1.16-2.20) -, butyl-paraben - linear (HR = 1.19; 95%CI = 1.14-1.23) and log-transformed (HR = 1.17; 95%CI = 1.01-1.35) - and total parabens - log-transformed (HR = 1.09; 95%CI = 1.02-1.17) and categorized into tertiles (HR = 1.62 for T3; 95%CI = 1.10-2.40) - were associated with an increased prostate cancer risk. In this study, higher concentrations of methyl-, butyl-, and total parabens were positively associated with prostate cancer risk. Further research is warranted to confirm these findings.

Toxicity of benzyl paraben on aquatic as well as terrestrial life

Parabens are derivatives of alkyl esters of p-hydroxybenzoic acid and come in different classes. These compounds are primarily used as antimicrobial preservative agents in many commercial products, including cosmetics and pharmaceuticals. Accordingly, Benzyl paraben (BeP) is known to be a potential endocrine disruptor. The aim of this study was to determine the toxicity of benzyl paraben (BeP) on aquatic and terrestrial organisms, specifically Scenedesmus sp., Moina macrocopa, and Eisenia fetida. All the organisms were treated with different concentrations of BeP (0.025 mg/L and 1000 mg/L), and LC25, LC50, and LC90 values were used to measure the toxicity levels. Results showed the LC values of BeP for M. macrocopa (3.3 mg/L, 4.7 mg/L, 7.3 mg/L) and E. fetida (173.2 mg/L, 479.8 mg/L, 1062 mg/L), respectively. Toxicity tests on green algae (Scenedesmus sp.) were conducted, the green algae were subjected to various BeP concentration. At 50 mg/L of BeP, cell viability was reduced to 56.2% and the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay indicated 35.4% viable cells. The chlorophyll value and the biochemical parameters of the algal cells were corroborative with the cell viability test. Lethal indices (LC50) for M. macrocopa and E. fetida were evaluated for their toxicity on biochemical properties and were found to be catalase (0.111 mg/L, 0.5 mg/L), lipid peroxidation (0.072 mg/L, 0.056 mg/L), and total protein (0.309 mg/L, 0.314 mg/L), respectively. Overall, this study demonstrated the toxic impact of BeP on non-target aquatic as well as terrestrial species.

Personal Care Products as a Contributing Factor to Antimicrobial Resistance: Current State and Novel Approach to Investigation

Antimicrobial resistance (AMR) is one of the world's industrialized nations' biggest issues. It has a significant influence on the ecosystem and negatively affects human health. The overuse of antibiotics in the healthcare and agri-food industries has historically been defined as a leading factor, although the use of antimicrobial-containing personal care products plays a significant role in the spread of AMR. Lotions, creams, shampoos, soaps, shower gels, toothpaste, fragrances, and other items are used for everyday grooming and hygiene. However, in addition to the primary ingredients, additives are included to help preserve the product by lowering its microbial load and provide disinfection properties. These same substances are released into the environment, escaping traditional wastewater treatment methods and remaining in ecosystems where they contact microbial communities and promote the spread of resistance. The study of antimicrobial compounds, which are often solely researched from a toxicological point of view, must be resumed considering the recent discoveries, to highlight their contribution to AMR. Parabens, triclocarban, and triclosan are among the most worrying chemicals. To investigate this issue, more effective models must be chosen. Among them, zebrafish is a crucial study system because it allows for the assessment of both the risks associated with exposure to these substances as well as environmental monitoring. Furthermore, artificial intelligence-based computer systems are useful in simplifying the handling of antibiotic resistance data and speeding up drug discovery processes.

Impact of Paraben Exposure on Adiposity-Related Measures: An Updated Literature Review of Population-Based Studies

Parabens are alkyl esters of p-hydroxybenzoic acid that are commonly used in pharmaceutical and cosmetic products. Humans are exposed to parabens when they use these products and through diet. There are growing concerns that paraben exposure can adversely impact human health. The endocrine-disrupting and obesogenic properties of parabens have been observed in animal studies and in vitro, prompting the increase in population-based studies of paraben exposure and adiposity-related endpoints. In this review, we summarize epidemiological studies published between 2017 and 2022 that examined paraben exposure in utero, between birth and adolescence, and in adulthood, in relation to adiposity-related measures. Overall, these studies provide some evidence that suggests that paraben exposure, especially during critical development windows, is associated with adiposity-related measures. However, we have noted several limitations in these studies, including the predominance of cross-sectional studies, inconsistent sample collection procedures, and small sample sizes, which should be addressed in future studies.

Health safety of parabens evaluated by selected in vitro methods

Seven selected parabens (4 allowed, 3 banned in cosmetics) were tested in order to confirm and expand historical data on their toxicological properties and safety. The aim was to apply novel in vitro methods, which have been sufficiently technically and scientifically validated for the purposes of toxicological testing of chemicals. The study included several toxicological endpoints such as skin/eye irritation, skin sensitization, endocrine disruption and genotoxicity. The battery of selected methods comprised regulatory accepted EpiDerm™ skin model (OECD TG 439); EpiOcular™ corneal model (OECD TG 492) and scientifically valid test method HET-CAM (DB-ALM Protocol No. 47); in chemico test DPRA (OECD TG 442C); in vitro test LuSens (OECD TG 442D) and in vitro test h-CLAT (OECD TG 442E); Ames MPF™ (Xenometrix) and XenoScreen YES/YAS (Xenometrix). Overall, none of the 4 allowed parabens exhibited skin/eye irritation or genotoxicity. However, all allowed parabens in cosmetics were predicted as samples with potentially sensitizing properties in the LuSens and h-CLAT test methods, but not confirmed by DPRA. Endocrine disruption was recorded only at high concentrations, whereas methyl paraben and ethyl paraben exhibited the lowest activity. This study confirmed the safety of use of the allowed parabens in the highest recommended concentrations in cosmetics or pharmaceuticals.

Parabens Permeation through Biological Membranes: A Comparative Study Using Franz Cell Diffusion System and Biomimetic Liquid Chromatography

Parabens (PBs) are used as preservatives to extend the shelf life of various foodstuffs, and pharmaceutical and cosmetic preparations. In this work, the membrane barrier passage potential of a subset of seven parabens, i.e., methyl-, ethyl-, propyl- isopropyl, butyl, isobutyl, and benzyl paraben, along with their parent compound, p-hydroxy benzoic acid, were studied. Thus, the Franz cell diffusion (FDC) method, biomimetic liquid chromatography (BLC), and in silico prediction were performed to evaluate the soundness of both describing their permeation through the skin. While BLC allowed the achievement of a full scale of affinity for membrane phospholipids of the PBs under research, the permeation of parabens through Franz diffusion cells having a carbon chain > ethyl could not be measured in a fully aqueous medium, i.e., permeation enhancer-free conditions. Our results support that BLC and in silico prediction alone can occasionally be misleading in the permeability potential assessment of these preservatives, emphasizing the need for a multi-technique and integrated experimental approach.

Patterns of environmental exposure to phenols in couples who plan to become pregnant

Phenols are widely used in consumer products and known for their reproductive toxicities. Little is known regarding the environmental exposure to phenols in couples prior to conception, a key period affecting fertility. We measured the urinary concentrations of six parabens and seven bisphenols in 903 pre-conception couples in China. We investigated the occurrence, distribution, source and health risk of phenols in husbands and wives separately, and the correlation and difference in phenol concentrations between couples. Similar distribution profiles of urinary phenols were observed between females and males. Methyl 4-hydroxybenzoate (MeP) and bisphenol A (BPA) were the predominant compounds. The level of urinary phenols in our population was mostly lower than the global levels. Exposure to phenols was linked to processed food and personal care products. The correlations between phenols in males and females were moderate (0.218-0.686), while the correlation in phenols between husband and wife was low (0.009-0.215). Female had a significantly higher urinary phenol levels than male (P < 0.05). Urinary phenols in couples were associated with family income, type of drinking water and frequency of household cleaning. Household factors accounted for ≤1.5% of variance in phenol levels between couples, suggesting that individual variations may be the major factor. Risk assessment showed that exposure to phenols posed a low hazard to 17.5% of the couples in our population. Our findings provide important evidence of environmental exposure to phenols in couples of child-bearing age.

Simple Portable Voltammetric Sensor Using Anodized Screen-Printed Graphene Electrode for the Quantitative Analysis of p-Hydroxybenzoic Acid in Cosmetics

Screen-printed graphene electrodes (SPGEs) have become a potential option in electrochemical applications because of their outstanding properties and disposable approach to miniaturize the electrodes for onsite analysis. Herein, the detection of para-hydroxybenzoic acid (PHBA) in cosmetics using the anodized SPGE has been pioneered and reported. The simple anodization of the SPGE surface was operated by anodic pretreatment at a constant potential on SPGE. The surface morphologies and electrochemical behaviors of anodized SPGEs in different anodization electrolytes were examined. Using anodized SPGE in a phosphate-buffered solution, a nontoxic solution, the sensitivity of PHBA detection was significantly improved compared with pristine SPGE owing to the increase of the polar oxygen-containing functional group during the anodization. The anodized SPGE could detect a PHBA down to 0.073 μmol/L. Finally, the developed anodized SPGE presented high ability and feasibility for PHBA detection in cosmetics. Furthermore, a facile electrode preparation step with a nontoxic solution can present high reproducibility and compatibility with a portable potentiostat for onsite PHBA detection during manufacturing.

Determination of contamination levels for multiple endocrine disruptors in hair from a non-occupationally exposed population living in Liege (Belgium)

Today, the interest in hair as alternative matrix for human biomonitoring of environmental pollutants has increased, but available data on chemical levels in hair remain scarce. In this study, the measurement of 2 bisphenols (A and S), 3 parabens (methyl-, ethyl- and propylparabens) and 8 perfluroralkyl compounds (PFCs) namely perfluoroctanesulfonate (PFOS), perfluorohexanesulfonate (PFHxS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluroroheptanoic acid (PFHpA), perfluoropentanoic acid (PFPeA) and perfluorohexanoic acid (PFHxA) was carried out, using a thoroughly validated UPLC-MS/MS method, in the hair from 114 adults living in Liege (Belgium) and surrounding areas. The most frequently quantified compounds in the population were: bisphenol S (97.4%, median = 31.9 pg·mg^-1), methylparaben (94.7%, median = 28.9 pg·mg^-1), bisphenol A (93.9%, median = 46.6 pg·mg^-1), ethylparaben (66.7%, median = 5.2 pg·mg^-1), propylparaben (54.8%, median = 16.4 pg·mg^-1) and PFOA (46.4%, median < 0.2 pg·mg^-1). The other PFCs were detected only in few samples although current exposure of the Belgian population to PFCs was previously demonstrated using blood analyses. Nonparametric statistical analyses were performed to evaluate the influence of gender, hair treatments and hair length, but no significant difference was observed. Only age was positively correlated with the propylparaben contamination. Although blood seems to remain more suitable for PFCs exposure assessment, the results of this study suggest that hair can be an appropriate matrix for biomonitoring of organic pollutants such as parabens or bisphenols.

Developing Eco-Friendly Skin Care Formulations with Microemulsions of Essential Oil

With the rising public awareness of environmental issues, consumers are increasingly demanding skin care products that create less environmental impact but still provide the same or even greater efficacy. In the skin care arena, microemulsions have been receiving increased attention as the promising delivery technology of skin care actives. Essential oils such as peppermint oil, lavender oil and eucalyptus oil are purported to have excellent antioxidant and antimicrobial properties that could be used as the eco-friendly alternatives for synthetic antioxidants and preservatives in the skin care formulations. This work therefore seeks to develop eco-friendly skin care formulations based on microemulsions of essential oil. Peppermint oil, lavender oil and eucalyptus oil were used as the oil phase to formulate naringin-loaded microemulsions, which demonstrated similar or better antioxidant and antimicrobial properties compared to the synthetic ones. When formulated into gel form, naringin-loaded microemulsion-gel formulations showed enhanced stability and release profile over their unformulated counterpart. Hence, microemulsions of essential oil developed in this work conferred a 4-fold benefits to the skin care formulations: (1) improved release (membrane permeation) of skin care active, (2) improved stability of skin care active, (3) as an eco-friendly alternative to synthetic antioxidant, and (4) a self-preserving system.

Residual behaviors and metabolic pathway of ethylparaben in Drosophila melanogaster

OBJECTIVE

Parabens are commonly used as preservatives in foodstuffs, cosmetics, and pharmaceutical products. The widespread use of parabens has led to their leaking into the environment. Concerns about the safety of parabens have recently increased due to their potential endocrine-disrupting effects as an emerging contaminant. Thus, it is necessary to study the metabolism of parabens in vivo.

METHODS

In this study, Drosophila melanogaster in males and females were exposed to ethylparaben (EP) concentration group (300 mg/L, 700 mg/L, and 1000 mg/L), and control group (0 mg/L) by the capillary feeding assay (CAFE). We quantified the activity of the detoxification-related carboxylesterase (CarE). The contents of EP metabolites in D. melanogaster, including p-hydroxybenzoic acid (PHBA), methylparaben (MP), and intact EP were carried out by high-performance liquid chromatography (HPLC). The regression model between EP metabolites (PHBA and MP) and CarE was developed using the Fourier series fitting method.

RESULTS

The general level of EP metabolites (PHBA, MP, and intact EP) accumulation was accounted for 5.6-11.5% in D. melanogaster. As EP accumulated, the activity of CarE increased, and the activity of CarE in females was higher than males, which is inconsistent with the result of EP intake dose. Additionally, there were significant differences in the proportion of EP metabolites between female and male flies, and the results of sex comparison were different depending on the EP treated groups and EP metabolites. In general, PHBA of EP hydrolytic product and MP of EP transesterification product in D. melanogaster were 41.4-63.9% and 10.4-24.6%, respectively. In terms of the rest of the EP existed in intact form and ranged from 22.4% to 34.0%. Moreover, the EP metabolites in the conjugated form were higher than those in the free form. The regression model between EP metabolites and CarE was established, showing that the CarE activity can be used to estimate the content of PHBA and MP.

CONCLUSION

The result indicates that the EP can accumulate in the body through food. Hydrolysis is the main metabolic pathway of EP in D. melanogaster, and transesterification is another metabolic pathway of EP. Additionally, the EP metabolites in flies mainly exist in conjugated form. Furthermore, the Fourier series fitting method model between EP metabolites and CarE, providing theoretical support to study the dose-effect relationship between metabolites of parabens and CarE. This study not only provides a mathematical basis for the safety evaluation of parabens, but also provides support for the further study of the toxicological effects of parabens.

Fetoplacental vasculature as a model to study human cardiovascular endocrine disruption

Increasing evidence has associated the exposure of endocrine-disrupting chemicals (EDCs) with the cardiovascular (CV) system. This exposure is particularly problematic in a sensitive window of development, pregnancy. Pregnancy exposome can affect the overall health of the pregnancy by dramatic changes in vascular physiology and endocrine activity, increasing maternal susceptibility. Moreover, fetoplacental vascular function is generally altered, increasing the risk of developing pregnancy complications (including cardiovascular diseases, CVD) and predisposing the foetus to adverse health risks later in life. Thus, our review summarizes the existing literature on exposures to EDCs during pregnancy and adverse maternal health outcomes, focusing on the human placenta, vein, and umbilical artery associated with pregnancy complications. The purpose of this review is to highlight the role of fetoplacental vasculature as a model for the study of human cardiovascular endocrine disruption. Therefore, we emphasize that the placenta, together with the umbilical arteries and veins, allows a better characterization of the pregnant woman's exposome. Consequently, it contributes to the protection of the mother and foetus against CV disorders in life.

Analytical method development and percutaneous absorption of propylidene phthalide, a cosmetic ingredient

Propylidene phthalide (PP) is a cosmetic ingredient used in the fragrance industry and regulated for the limited content of 0.01% in cosmetic products in Korea. The aim of this study was to determine PP dermal absorption rate according to the Korea Ministry of Food and Drug Safety (MFDS) guidelines using in vitro Franz diffusion system. An analytical method in assessing PP was developed through method validation using LC-MS/MS. Linearity, precision, and accuracy were acceptable based upon MFDS guidelines. The stability of PP in receptor fluid (50% ethanol) at 32°C was sufficient up to 24 hr. Cream formulation (o/w) was topically applied to excised rat skin at a dose of 113 mg/cm² containing 0.7% PP. The time points for receptor fluid collection were set at 0, 1, 2, 4, 8, 12, and 24 hr. After 24 hr, the remaining formulation on the skin and stratum corneum (SC) were collected through swabbing with an alcohol cotton and tape stripping, respectively. The collected samples (swabbed-remained formulation, SC, and skin) were extracted using acetonitrile for 24 hr. Total dermal absorption rate of PP was approximately 24% in cream formulation. These findings may be used for further exposure evaluation of PP in human consumers.

Young children's exposure to phenols in the home: Associations between house dust, hand wipes, silicone wristbands, and urinary biomarkers

BACKGROUND

Environmental phenols, such as parabens, bisphenol A, and triclosan, are ubiquitous in indoor environments because of their use in packaging, plastics, personal care products, and as anti-microbials. The primary pathways of exposure, as well as habits and behaviors that may lead to greater exposure, are still unclear.

OBJECTIVES

Herein, we investigate the relationships between phenols found in residential environments by comparing levels in paired samples of house dust and hand wipes with children's urine. In addition, phenols were analyzed in a novel exposure tool, the silicone wristbands, to investigate which external matrix best correlates with individual exposure based on urinary phenol biomarkers.

METHODS

Children aged 3-6 years in central North Carolina, United States, provided paired hand wipe (n = 202), wristband (n = 76), and spot urine samples (n = 180), while legal guardians completed questionnaires on habits and behaviors. House dust samples (n = 186) were collected from the main living area during home visits completed between 2014 and 2016.

RESULTS

Environmental phenols were detected frequently in all matrices investigated. Ethyl, methyl, and propylparaben levels observed in hand wipes, dust, and on wristbands were significantly correlated to their associated urinary biomarkers. In addition, intra-paraben correlations were noted, with biomarkers of ethyl, methyl, and propylparabens generally positively and significantly correlated, which suggests co-application of parabens in products. Triclosan levels in dust were positive and significantly correlated with levels in hand wipes and wristbands and with urinary concentrations, suggesting non-personal care product sources may be important in children's overall triclosan exposure. Generally, chemicals on wristbands were more highly correlated with urinary biomarkers than with chemicals in hand wipes or house dust. In addition, more frequent lotion use was positively associated with urinary concentrations of paraben biomarkers.

CONCLUSIONS

Our results suggest that the home environment is an important source of exposure which has been under-investigated for some environmental phenols (e.g., triclosan in house dust). Associations between wristbands and biomarkers of exposure, which were stronger than for hand wipes and house dust, suggest that silicone wristbands may provide a suitable exposure assessment tool for some phenols.