Environmental exposure to parabens and sperm chromosome disomy

Biomonitoring of parabens in wild boars through hair samples analysis

Parabens are compounds widely utilized in the industry as preservative additives to personal care products, cosmetics and food. They pollute the environment and penetrate to the living organisms through the digestive tract, respiratory system and skin. Till now the knowledge about exposure of terrestrial wild mammals to parabens is extremely scarce. Therefore, this study for the first time assessed the concentration levels of five parabens commonly used in industry (methylparaben-MeP, ethylparaben-EtP propylparaben-PrP, benzylparaben -BeP and butylparaben-BuP). Substances have been analyzed in hair samples collected from wild boars using liquid chromatography-mass spectrometry (LC-MS) method. The hair is a matrix, which allows to study long-term exposure of organisms to parabens. During this study MeP was noted in 96.3% of samples with mean 88.3±72.9 pg/mg, PrP in 87.0% of samples with mean 8.5±3.3 pg/mg, BeP in 44.4% of samples with mean 17.2±12.3 pg/mg and EtP in 11.1% of samples with mean 17.2±4.8 pg/mg. In turn BuP was noted only in 3.7% of samples with concentration levels below limit of quantification (2.6 pg/mg). Statistically significant intragender differences in parabens levels have not been noted. Only BeP concentration levels depended on industrialization and density of human population of area, where the animals lived. This study indicates that wild boars are exposed to parabens, especially to MeP and PrP, and analysis of the hair seems to be a useful tool of biomonitoring of parabens in wild mammals.

Exposure estimates of parabens from personal care products compared with biomonitoring data in human hair from Northeast China

Parabens (PBs), a class of endocrine-disrupting chemicals (EDCs), are extensively used as additives in personal care products (PCPs); however, distinguishing between endogenous and exogenous contamination from PCPs in hair remains a challenge. We conducted a comprehensive analysis of the levels, distribution patterns, impact factors, and sources of PBs in 119 human hair samples collected from Changchun, northeast China. The detection rates of methylparaben (MeP), propylparaben (PrP), and ethylparaben (EtP) in hair samples were found to be 100%. The concentration of PBs in hair followed the order of MeP (57.48 ng/g) > PrP (46.40 ng/g) > EtP (6.80 ng/g). The concentration of PrP in female hair was significantly higher (65.38 ng/g) than that observed in male hair (7.82 ng/g) (p < 0.05). The levels of excretion rates of MeP (ERMeP) and excretion rates of PrP (ERPrP) in the hair-dying samples (ERMeP: 17.89 ng/day; ERPrP: 14.15 ng/day) were found to be 2.52 and 2.40 times higher, respectively, compared to the non-hair-dying samples (ERMeP: 7.09 ng/day; ERPrP: 6.05 ng/day). However, the system exposure dosage (SED) results revealed that although hair dyes exhibited higher PBs, human exposure was found to be lower than certain PCPs. The results of the correlation analysis revealed that toner, face cream, body lotion, and hair conditioner were identified as the primary sources of PBs in male hair. Furthermore, the human exposure resulting from the utilization of female hair dye and serum exhibited a positive correlation with hair ERMeP and ERPrP levels, indicating in the screening of samples, excluding hair samples using hair dye and haircare essential oil can effectively avoid the interference caused by exogenous contamination from PCPs.

Natural alternatives from your garden for hair care: Revisiting the benefits of tropical herbs

Hair shampoos containing botanical ingredients without synthetic additives, such as parabens, petrochemicals, sulfates and silicones are more skin- and environmentally friendly. In recent years, there is a growing demand for shampoo products with botanical extracts. Shampoos with botanical extracts are well-known for their perceived health benefits. They are also generally milder, non-toxic, natural, and less likely to disrupt the hair and scalp's natural pH and oil balance. Many also believe that shampoos with botanical origins have higher standards of quality. Numerous botanical extracts had been used as natural active ingredients in cosmetic formulations to meet consumer demands. In this review, we have revisited six tropical plants commonly added as natural active ingredients in shampoo formulations: Acacia concinna, Camellia oleifera, Azadirachta indica, Emblica officinalis, Sapindus mukorossi, and Garcinia mangostana. These plants have been traditionally used for hair care, and scientific research has shown that they exhibit relevant physicochemical properties and biological activities that are beneficial for hair care and scalp maintenance.

Quantification and stability assessment of urinary phenolic and acidic biomarkers of non-persistent chemicals using the SPE-GC/MS/MS method

Nowadays, people are exposed to numerous man-made chemicals, many of which are ubiquitously present in our daily lives, and some of which can be hazardous to human health. Human biomonitoring plays an important role in exposure assessment, but complex exposure evaluation requires suitable tools. Therefore, routine analytical methods are needed to determine several biomarkers simultaneously. The aim of this study was to develop an analytical method for quantification and stability testing of 26 phenolic and acidic biomarkers of selected environmental pollutants (e.g., bisphenols, parabens, pesticide metabolites) in human urine. For this purpose, a solid-phase extraction coupled with gas chromatography and tandem mass spectrometry (SPE-GC/MS/MS) method was developed and validated. After enzymatic hydrolysis, urine samples were extracted using Bond Elut Plexa sorbent, and prior to GC, the analytes were derivatized with N-trimethylsilyl-N-methyl trifluoroacetamide (MSTFA). Matrix-matched calibration curves were linear in the range of 0.1-1000 ng mL^-1 with R > 0.985. Satisfactory accuracy (78-118%), precision (< 17%), and limits of quantification (0.1-0.5 ng mL^-1) were obtained for 22 biomarkers. The stability of the biomarkers in urine was assayed under different temperature and time conditions that included freezing and thawing cycles. All tested biomarkers were stable at room temperature for 24 h, at 4 °C for 7 days, and at -20 °C for 18 months. The total concentration of 1-naphthol decreased by 25% after the first freeze-thaw cycle. The method was successfully used for the quantification of target biomarkers in 38 urine samples.

Within-day variability, predictors, and risk assessments of exposure to parabens among Chinese adult men

BACKGROUND

Parabens, as suspected endocrine disruptors, are widely used in personal care products and pharmaceuticals. However, variability, predictors, and risk assessments of human exposure to parabens are not well characterized.

OBJECTIVE

To evaluate within-day variability, predictors, and risk assessments of exposure to parabens among Chinese adult men.

METHODS

We measured four parabens including methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP) in repeated urine samples from 850 Chinese adult men. We examined the variability by intraclass correlation coefficients (ICCs) and identified the predictors by multivariable linear mixed models. We assessed risks of paraben exposures based on the estimated daily intake (EDI).

RESULTS

The four parabens were detected in >76% of urinary samples. We observed fair to good to high reproducibility (ICCs: 0.71 to 0.86) for urinary paraben concentrations within one day. Use of facial cleanser was associated with higher four urinary paraben concentrations. Increasing age, taking medicine, intravenous injection, and interior decoration in the workplace were related to higher urinary concentrations of specific parabens. Smoking and drinking were associated with lower urinary concentrations of specific parabens. The maximum EDIs for the four parabens ranged from 13.76 to 848.68 μg/kg bw/day, and 0.9% of participants had the hazard quotient values > 1 driven by PrP exposure.

CONCLUSIONS

Urinary paraben concentrations were less variable within one day. Several lifestyle characteristics including use of facial cleanser and pharmaceuticals may contribute to paraben exposures.

Determination of Parabens and Their Metabolites in Seminal Plasma from Chinese Men by Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS)

Parabens are endocrine-disrupting chemicals (EDCs) that have estrogen-like activities and may cause male reproductive disorders. Here, we developed a method for the simultaneous determination of four parabens (MeP, EtP, n-PrP, n-BuP) and two metabolites (4-HB and 3,4-DHB) in human seminal plasma by UPLC-MS/MS. The method was used to analyze 144 seminal plasma samples from Chinese males. MeP, EtP, n-PrP, and 4-HB were the dominant compounds. MeP, EtP, and n-PrP were significantly correlated to each other. In addition, 4-HB was significantly correlated to MeP, EtP, n-PrP, and 3,4-DHB, respectively. The results provide direct evidence that parabens and their metabolites are widely distributed in the male reproductive system. The study presents the paraben metabolites levels in human seminal plasma for the first time.

Evaluation of Parabens and Bisphenol A Concentration Levels in Wild Bat Guano Samples

Parabens and bisphenol A are synthetic compounds found in many everyday objects, including bottles, food containers, personal care products, cosmetics and medicines. These substances may penetrate the environment and living organisms, on which they have a negative impact. Till now, numerous studies have described parabens and BPA in humans, but knowledge about terrestrial wild mammals' exposure to these compounds is very limited. Therefore, during this study, the most common concentration levels of BPA and parabens were selected (such as methyl paraben-MeP, ethyl paraben-EtP, propyl paraben-PrP and butyl paraben-BuP) and analyzed in guano samples collected in summer (nursery) colonies of greater mouse-eared bats (Myotis myotis) using liquid chromatography with the tandem mass spectrometry (LC-MS-MS) method. MeP has been found in all guano samples and its median concentration levels amounted to 39.6 ng/g. Other parabens were present in smaller number of samples (from 5% for BuP to 62.5% for EtP) and in lower concentrations. Median concentration levels of these substances achieved 0.95 ng/g, 1.45 ng/g and 15.56 ng/g for EtP, PrP and BuP, respectively. BPA concentration levels did not exceed the method quantification limit (5 ng/g dw) in any sample. The present study has shown that wild bats are exposed to parabens and BPA, and guano samples are a suitable matrix for studies on wild animal exposure to these substances.

From Oxidative Stress to Male Infertility: Review of the Associations of Endocrine-Disrupting Chemicals (Bisphenols, Phthalates, and Parabens) with Human Semen Quality

Exposure to endocrine-disrupting chemicals (EDCs) may result in oxidative stress and endocrine system disturbance, which can have an impact on human reproduction and development. In male reproductive health, EDCs have been related to impaired reproductive function and male infertility, altered fetal development, and testicular germ-cell, prostate, and breast cancers. We conducted an electronic search using PubMed on endocrine disruptors related to oxidative stress and male infertility, and evaluated their association with endocrine-disrupting chemicals (bisphenols, phthalates, and parabens) in 25 articles. Higher levels of urinary bisphenols showed correlation with impaired semen quality and increased DNA damage. Considering phthalates and their metabolites, all studies found a positive association between urinary levels of phthalates and at least one semen parameter indicative of low semen quality; some studies also revealed sperm DNA damage. The studies on parabens less often revealed correlation of urinary parabens concentrations with a decrease in sperm count, as well as motility and DNA damage. Moreover, EDCs can elevate ROS production and lipid peroxidation, increase apoptosis, induce epigenetic modifications, and change the Y:X sperm chromosome ratio and sperm protein composition. Our review revealed detrimental effects of EDCs on semen quality and sperm DNA integrity-especially in BPA and phthalates, but also in parabens.

Biomonitoring parabens in dogs using fur sample analysis - Preliminary studies

Parabens are widely used in the food, cosmetics and pharmaceutical industry and are widespread in the environment. As endocrine disruptors, parabens have adverse effects on living organisms. However, knowledge of the exposure of domestic animals to parabens is extremely scarce. Therefore, this study assessed the exposure level of dogs to three parabens commonly used in industry (i.e. methylparaben - MeP, ethylparaben - EtP and propylparaben - PrP) using fur sample analysis in liquid chromatography-tandem mass spectrometry. The presence of parabens has been noted in the samples collected from all dogs included in the study (n = 30). Mean concentrations of MeP, EtP and PrP in the fur of dogs were 176 (relative standard deviation - RSD = 127.48%) ng/g dry weight (dw), 48.4 (RSD = 163.64%) ng/g dw and 79.8 ng/g dw (RSD = 151.89%), respectively. The highest concentrations were found for MeP (up to 1023 ng/g dw). Concentrations of MeP and EtP in males were statistically higher than those in females (p < 0.05). Statistically significantly higher concentration levels of PrP in young animals (up to three years old) were also found. This is the first study concerning the use of fur samples to evaluate the exposure of domestic animals to parabens. The results indicate that an analysis of the fur may be a useful tool of paraben biomonitoring in dogs. The presence of parabens in the canine fur also suggests that these substances may play a role in veterinary toxicology. However, many aspects connected with this issue are not clear and require further study.

Evaluation of human exposure to parabens in north eastern Poland through hair sample analysis

Parabens (PBs) are a group of substances commonly used in industry. They also pollute the environment, penetrate into living organisms and adversely affect various internal organs. During this study, the degree of exposure of people living in Olsztyn, a city in north eastern Poland, to selected parabens most often used in industry was studied. The chemicals under investigation included: methyl paraben—MePB, ethyl paraben—EtPB, propyl paraben—PrPB, benzyl paraben BePB and butyl paraben -BuPB. To this aim, hair samples collected from the scalps of 30 volunteers were analyzed using a liquid chromatography–mass spectrometry technique. All PBs studied were present in a high percentage of analyzed samples (from 76.7% in the case of BePB to 100% in the case of MePB and PrPB). The mean concentration levels were 4425.3 pg/mg for MeBP, 704.0 pg/mg for EtPB, 825.7 pg/mg for PrPB, 135.2 pg/mg for BePB and 154.5 pg/mg for BuPB. Significant differences in PB concentration levels between particular persons were visible. On the other hand, gender, age and artificial hair coloring did not cause statistically significant differences in PB levels. Obtained results have clearly indicated that people living in north eastern Poland are exposed to various PBs, and therefore these substances may affect their health status. However, the evaluation of PBs influence on human health requires further research.

FISH and Chimps: Insights into Frequency and Distribution of Sperm Aneuploidy in Chimpanzees (Pan troglodytes)

Numerical chromosomal aberrations in sperm are considered to be a major factor in infertility, early pregnancy loss and syndromes with developmental and cognitive disabilities in mammals, including primates. Despite numerous studies in human and farm animals, the incidence and importance of sperm aneuploidies in non-human primate remains mostly undetermined. Here we investigated the incidence and distribution of sperm aneuploidy in chimpanzees (Pan troglodytes), the species closest to human. We identify evolutionary conserved DNA sequences in human and chimpanzee and selected homologous sub-telomeric regions for all chromosomes to build custom probes and perform sperm-FISH analysis on more than 10,000 sperm nuclei per chromosome. Chimpanzee mean autosomal disomy rate was 0.057 ± 0.02%, gonosomes disomy rate was 0.198% and the total disomy rate was 1.497%. The proportion of X or Y gametes was respectively 49.94% and 50.06% for a ratio of 1.002 and diploidy rate was 0.053%. Our data provide for the first time an overview of aneuploidy in non-human primate sperm and shed new insights into the issues of aneuploidy origins and mechanisms.

Review of the safety of application of cosmetic products containing parabens

Cosmetics are a source of lifetime exposure to various substances including parabens, being the most popular synthetic preservatives. Because the use of cosmetics shows an increasing trend and some adverse health outcomes of parabens present in these products have been reported, the present review focused on the safety of dermal application of these compounds. Special attention has been paid to the absorption of parabens and their retention in the human body in the intact form, as well as to their toxicological characteristics. Particular emphasis has been placed on the estrogenic potential of parabens. Based on the available published data of the concentrations of parabens in various kinds of cosmetics, the average ranges of systemic exposure dose (SED) for methylparaben, ethylparaben, propylparaben, and butylparaben have been calculated. Safety evaluations [margin of safety (MoS)] for these compounds, based on their aggregate exposure, have also been performed. Moreover, evidence for the negative impact of methylparaben on skin cells has been provided, and the main factors that may intensify dermal absorption of parabens and their impact on the skin have been described. Summarizing, the use of single cosmetics containing parabens should not pose a hazard for human health; however, using excessive quantities of cosmetic preparations containing these compounds may lead to the development of unfavorable health outcomes. Due to the real risk of estrogenic effects, as a result of exposure to parabens in cosmetics, simultaneous use of many cosmetic products containing these preservatives should be avoided.

Controversy around parabens: Alternative strategies for preservative use in cosmetics and personal care products

Parabens usage as preservatives in cosmetics and personal care products have been debated among scientists and consumers. Parabens are easy to production, effective and cheap, but its safety status remains controversial. Other popular cosmetics preservatives are formaldehyde, triclosan, methylisothiazolinone, methylchloroisothiazolinone, phenoxyethanol, benzyl alcohol and sodium benzoate. Although their high antimicrobial effectiveness, they also exhibit some adverse health effects. Lately, scientists have shown that natural substances such as essential oils and plant extracts present antimicrobial potential. However, their use in cosmetic is a challenge. The present review article is a comprehensive summary of the available methods to prevent microbial contamination of cosmetics and personal care products, which can allow reducing the use of parabens in these products.

Environmental and occupational exposures associated with male infertility

The upsurge in male infertility over the last two decades, possibly due to environmental exposure, has raised significant interest, particularly boosted by reports from fertility clinics, which showed that chronic diseases and hereditary or other medical conditions might only partially explain current incidence of male infertility. Both environmental and occupational settings may have a significant role in exposure to complex mixtures of endocrine disruptors (ED), which play a major role in fertility disorders. The aim of this review is to give an insight into the current knowledge on exposure settings which may be associated with male infertility. Our study relied on a systematic search of PubMed, Scopus, and Web of Science for articles published between January 2000 and September 2020. It showed that some well documented factors associated with male infertility include smoking, and physiological disturbances or chronic diseases such as obesity and diabetes, which in turn, may also reflect lifestyle choices and environmental exposures, especially to EDs such as phthalates, bisphenols, pesticides, and flame retardants. However, the number of studies on the aetiology of male infertility is still too low in comparison with the size of affected population. Occupational health follow-ups and medical surveillance do not collect any data on male infertility, even though ED chemicals are part of many technological processes.

Maternal serum concentrations of bisphenol A and propyl paraben in early pregnancy are associated with male infant genital development

STUDY QUESTION

Are maternal serum phthalate metabolite, phenol and paraben concentrations measured at 10-17 weeks of gestation associated with male infant genital developmental outcomes, specifically cryptorchidism, anogenital distance (AGD), penile length and testicular descent distance, at birth and postnatally?

SUMMARY ANSWER

Maternal serum bisphenol A (BPA) concentration at 10-17 weeks of gestation was positively associated with congenital or postnatally acquired cryptorchidism, and n-propyl paraben (n-PrP) concentration was associated with shorter AGD from birth to 24 months of age.

WHAT IS KNOWN ALREADY

Male reproductive disorders are increasing in prevalence, which may reflect environmental influences on foetal testicular development. Animal studies have implicated phthalates, BPA and parabens, to which humans are ubiquitously exposed. However, epidemiological studies have generated conflicting results and have often been limited by small sample size and/or measurement of chemical exposures outside the most relevant developmental window.

STUDY DESIGN, SIZE, DURATION

Case-control study of cryptorchidism nested within a prospective cohort study (Cambridge Baby Growth Study), with recruitment of pregnant women at 10-17 postmenstrual weeks of gestation from a single UK maternity unit between 2001 and 2009 and 24 months of infant follow-up. Of 2229 recruited women, 1640 continued with the infancy study after delivery, of whom 330 mothers of 334 male infants (30 with congenital cryptorchidism, 25 with postnatally acquired cryptorchidism and 279 unmatched controls) were included in the present analysis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Maternal blood was collected at enrolment, and serum levels of 16 phthalate metabolites, 9 phenols (including BPA) and 6 parabens were measured using liquid chromatography/tandem mass spectrometry. Logistic regression was used to model the association of cryptorchidism with serum chemical concentrations, adjusting for putative confounders. Additionally, offspring AGD, penile length and testicular descent distance were assessed at 0, 3, 12, 18 and 24 months of age, and age-specific Z scores were calculated. Associations between serum chemical levels and these outcomes were tested using linear mixed models.

MAIN RESULTS AND THE ROLE OF CHANCE

Maternal serum BPA concentration was associated with offspring all-type cryptorchidism both when considered as a continuous exposure (adjusted odds ratio per log10 μg/l: 2.90, 95% CI 1.31-6.43, P =  0.009) and as quartiles (phet =  0.002). Detection of n-PrP in maternal serum was associated with shorter AGD (by 0.242 standard deviations, 95% CI 0.051-0.433, P =  0.01) from birth to 24 months of age; this reduction was independent of body size and other putative confounders. We did not find any consistent associations with offspring outcomes for the other phenols, parabens, and phthalate metabolites measured.

LIMITATIONS, REASONS FOR CAUTION

We cannot discount confounding by other demographic factors or endocrine-disrupting chemicals. There may have been misclassification of chemical exposure due to use of single serum measurements. The cohort was not fully representative of pregnant women in the UK, particularly in terms of smoking prevalence and maternal ethnicity.

WIDER IMPLICATIONS OF THE FINDINGS

Our observational findings support experimental evidence that intrauterine exposure to BPA and n-PrP during early gestation may adversely affect male reproductive development. More evidence is required before specific public health recommendations can be made.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by a European Union Framework V programme, the World Cancer Research Fund International, the Medical Research Council (UK), Newlife the Charity for Disabled Children, the Mothercare Group Foundation, Mead Johnson Nutrition and the National Institute for Health Research Cambridge Comprehensive Biomedical Research Centre. Visiting Fellowship (J.M.): Regional Programme 'Jiménez de la Espada' for Research Mobility, Cooperation and Internationalization, Seneca Foundation-Science and Technology Agency for the Region of Murcia (No. 20136/EE/17). K.O. is supported by the Medical Research Council (UK) (Unit Programme number: MC_UU_12015/2). The authors declare no conflict of interest.

Endocrine disrupting chemicals: Impacts on human fertility and fecundity during the peri-conception period

It is becoming increasingly difficult to avoid exposure to man-made endocrine disrupting chemicals (EDCs) and environmental toxicants. This escalating yet constant exposure is postulated to partially explain the concurrent decline in human fertility that has occurred over the last 50 years. Controversy however remains as to whether associations exist, with conflicting findings commonly reported for all major EDC classes. The primary aim of this extensive work was to identify and review strong peer-reviewed evidence regarding the effects of environmentally-relevant EDC concentrations on adult male and female fertility during the critical periconception period on reproductive hormone concentrations, gamete and embryo characteristics, as well as the time to pregnancy in the general population. Secondly, to ascertain whether individuals or couples diagnosed as sub-fertile exhibit higher EDC or toxicant concentrations. Lastly, to highlight where little or no data exists that prevents strong associations being identified. From the greater than 1480 known EDCs, substantial evidence supports a negative association between exposure to phthalates, PCBs, PBDEs, pyrethroids, organochloride pesticides and male fertility and fecundity. Only moderate evidence exists for a negative association between BPA, PCBs, organochloride pesticides and female fertility and fecundity. Overall fewer studies were reported in women than men, with knowledge gaps generally evident for both sexes for all the major EDC classes, as well as a paucity of female fertility studies following exposure to parabens, triclosans, dioxins, PFAS, organophosphates and pyrethroids. Generally, sub-fertile individuals or couples exhibit higher EDC concentrations, endorsing a positive association between EDC exposure and sub-fertility. This review also discusses confounding and limiting factors that hamper our understanding of EDC exposures on fertility and fecundity. Finally, it highlights future research areas, as well as government, industry and social awareness strategies required to mitigate the negative effects of EDC and environmental toxicant exposure on human fertility and fecundity.

Male urinary biomarkers of antimicrobial exposure and bi-directional associations with semen quality parameters

Antimicrobials including parabens, triclosan, and triclocarban have endocrine disrupting properties. Among 501 male partners of couples planning to become pregnant, preconception urinary biomarkers of parabens, triclosan and triclocarban exposure were quantified in spot urine samples. Men also provided two fresh semen samples collected approximately one month to undergo 24-h semen quality analysis. Linear mixed-effects models, adjusted for creatinine, race, age and body mass index, were utilized to assess the relationship between log transformed chemical concentrations rescaled by their standard deviations and semen parameters. Methyl, ethyl and butyl parabens, were associated with diminished sperm count and several sperm motility parameters. Hydroxylated paraben metabolites and triclosan were significantly positively associated with select semen quality parameters. Overall, our findings suggest that specific urinary parabens found in consumer goods (methyl, ethyl and butyl parabens) may adversely impact sperm quality parameters among reproductive-age male partners of couples trying for pregnancy.