Human Exposure Levels Research Articles

Perfluorooctanoic Acid (PFOA): Environmental Sources, Chemistry, Toxicology, and Potential Risks

ABSTRACT Attention regarding perfluoroalkyl and polyfluoroalkyl substances (PFAS) has increased in recent years, due to recognition of widespread environmental presence, recognition of a chemical structure that confers resistance to degradation, and reported health concerns. Historical common exposure sources include food, drinking water, occupational circumstances, and products in commerce (e.g., carpeting, clothing, paper products). Early-2000’s data showed perfluorooctanoic acid (PFOA) was present in blood samples from nearly all the U.S. general population (>99%). Alterations in industrial manufacturing processes, increased regulatory scrutiny, and advanced water treatment options have reduced the reported human body burden of PFAS in the U.S., including for PFOA. Human serum concentrations of PFOA, which do not identify the source(s) of exposure, have exhibited a substantial decrease (~63%) between the 1999–2000 and the 2013–2014 NHANES monitoring by the Centers for Disease Control and Prevention (CDC). With respect to both noncancer and potential cancer effects that may be associated with reported serum levels of PFOA, conclusions regarding an absence of effects, or insufficient information to suggest adverse effects, prevent a consistent conclusion about the occurrence and magnitude of human health effects. In the last several years, a number of state and federal agencies have developed health advisories or guideline values for drinking water exposure that are in the sub-ppb range. In 2016, a USEPA Health Advisory of 0.07 ppb was released, which stands in contrast to 2016 Health-based Values from Health Canada ranging from 0.2 ppb (PFOA) to 30 ppb, and a few other U.S. states with values even less than that of USEPA (e.g., MN, NJ, VT). Further work is necessary to distinguish in transparent fashion between drinking water levels that intentionally are set on a conservative basis to protect human health vs exposure levels that may be associated with tangible adverse effects.

Assessing Effect of Targeting Reduction of PM2.5 Concentration on Human Exposure and Health Burden in Hong Kong Using Satellite Observation

Targeting reduction of PM2.5 concentration lessens population exposure level and health burden more effectively than uniform reduction does. Quantitative assessment of effect of the targeting reduction is limited because of the lack of spatially explicit PM2.5 data. This study aimed to investigate extent of exposure and health benefits resulting from the targeting reduction of PM2.5 concentration. We took advantage of satellite observations to characterize spatial distribution of PM2.5 concentration at a resolution of 1 km. Using Hong Kong of China as the study region (804 satellite’s pixels covering its residential areas), human exposure level (cρ) and premature mortality attributable to PM2.5 (Mort) for 2015 were estimated to be 25.9 μg/m3 and 4112 people per year, respectively. We then performed 804 diagnostic tests that reduced PM2.5 concentrations by −1 μg/m3 in different areas and a reference test that uniformly spread the −1 μg/m3. We used a benefit rate from targeting reduction (BRT), which represented a ratio of declines in cρ (or Mort) with and without the targeting reduction, to quantify the extent of benefits. The diagnostic tests estimated the BRT levels for both human exposure and premature mortality to be 4.3 over Hong Kong. It indicates that the declines in human exposure and premature mortality quadrupled with a targeting reduction of PM2.5 concentration over Hong Kong. The BRT values for districts of Hong Kong could be as high as 5.6 and they were positively correlated to their spatial variabilities in population density. Our results underscore the substantial exposure and health benefits from the targeting reduction of PM2.5 concentration. To better protect public health in Hong Kong, super-regional and regional cooperation are essential. Meanwhile, local environmental policy is suggested to aim at reducing anthropogenic emissions from mobile and area (e.g., residential) sources in central and northwestern areas.

Exposure marker discovery of di-2(propylheptyl) phthalate using ultra-performance liquid chromatography-mass spectrometry and a rat model

Di-(2-propylheptyl) phthalate (DPHP) is a plasticizer and has been suggested to be a subchronic toxicant in rats. DPHP has been approved to be used in food containers and handling by the U.S. Food and Drug Administration. The use of DPHP is still increasing, and the risk of human exposure to DPHP via food may be high. Exposure markers measured in human samples are commonly used to monitor human exposure levels. Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and a rat model were used to discover tentative DPHP exposure markers. DPHP and mono-(2-propylheptyl) phthalate (MPHP) were used as the precursors for calculating metabolite candidates using biotransformation mass changes of known enzymatic reactions. A rat model was designed to validate these metabolite candidates as tentative exposure markers. A total of 28 signals show dose–response relationships and these signals contain a few isomers. The chemical structures of 15 tentative exposure marker signals were speculated based on the product ion mass spectra from MS/MS analysis. These 15 signals included 7 chemical structures and some of them may be isomers. The different arrangement of the atoms in space of these isomers should be validated by standard compounds in the future studies. Among the 7 speculated chemical structures, 2 structures were novel tentative DPHP metabolites, and 5 structures have been previously reported in the literature. The results indicate that using UPLC-MS and a rat model can be used to identify tentative toxicant exposure markers.

Cannabinoid exposure and altered DNA methylation in rat and human sperm

ABSTRACTLittle is known about the reproductive effects of paternal cannabis exposure. We evaluated associations between cannabis or tetrahydrocannabinol (THC) exposure and altered DNA methylation in sperm from humans and rats, respectively. DNA methylation, measured by reduced representation bisulfite sequencing, differed in the sperm of human users from non-users by at least 10% at 3,979 CpG sites. Pathway analyses indicated Hippo Signaling and Pathways in Cancer as enriched with altered genes (Bonferroni p < 0.02). These same two pathways were also enriched with genes having altered methylation in sperm from THC-exposed versus vehicle-exposed rats (p < 0.01). Data validity is supported by significant correlations between THC exposure levels in humans and methylation for 177 genes, and substantial overlap in THC target genes in rat sperm (this study) and genes previously reported as having altered methylation in the brain of rat offspring born to parents both exposed to THC during adolescence. In humans, cannabis use was also associated with significantly lower sperm concentration. Findings point to possible pre-conception paternal reproductive risks associated with cannabis use.

Spatial distribution, source analysis, and health risk assessment of heavy metals contamination in house dust and surface soil from four major cities of Nepal

Raising population, deteriorating environmental conditions and limiting natural resources to handle the key environmental health problems have critically affected human health and the environment. Policy makers and planners in Nepal are more concerned today than at any other time in the past about the deterioration of the environmental condition. Therefore, understanding the connection between pollution and human wellbeing is fundamental endeavors to control pollution exposures and secure human wellbeing. This ability is especially critical for countries like Nepal where the issues of environmental pollution have customarily taken a second place to request for economic development. In this study, spatial distribution and sources of 12 heavy metals (HMs) were investigated in surface soils (n = 24) and house dust (n = 24) from four major urban areas of Nepal in order to mark the pollution level. Additionally, a health risk was estimated to establish the link between HMs pollution and human health. Results showed that the median concentration of Ag, Cd, Co, Cr, Cu, Ni, Pb, Sb, Mn and Zn in soil and dust were 2–13 times greater than the background value. The As, Zn, Cu, Cd, and Pb showed a relatively higher spatial variability in soil and dust. Zn was the most abundant metal measured in dust and soil and accounted for 59% and 55% of ∑7HMs, respectively. The HMs in soil and dust were poorly correlated with total organic carbon (TOC) and black carbon (BC), suggesting little or no influence on HMs contamination. Source analysis study indicated the distribution of Cr, Ni, Sb, Ag, Pb, Cu, and Zn in soil and dust are mainly affected by anthropogenic sources, particularly traffic emissions, industrial source, and domestic households materials, while Co, Fe, As, Mn and Cd were from natural sources. The estimated carcinogenic risk (CR) of HMs in soil and dust exceeded the acceptable level of human exposure, recommending significant CR to the local population.

Transgenerational effects of maternal bisphenol: a exposure on offspring metabolic health.

Exposure to the endocrine disruptor bisphenol A (BPA) is ubiquitous and associated with health abnormalities that persist in subsequent generations. However, transgenerational effects of BPA on metabolic health are not widely studied. In a maternal C57BL/6J mice (F0) exposure model using BPA doses that are relevant to human exposure levels (10 μg/kg/day, LowerB; 10 mg/kg/day, UpperB), we showed male- and dose-specific effects on pancreatic islets of the first (F1) and second generation (F2) offspring relative to controls (7% corn oil diet; control). In this study, we determined the transgenerational effects (F3) of BPA on metabolic health and pancreatic islets in our model. Adult F3 LowerB and UpperB male offspring had increased body weight relative to Controls, however glucose tolerance was similar in the three groups. F3 LowerB, but not UpperB, males had reduced β-cell mass and smaller islets which was associated with increased glucose-stimulated insulin secretion. Similar to F1 and F2 BPA male offspring, staining for markers of T-cells and macrophages (CD3 and F4/80) was increased in pancreas of F3 LowerB and UpperB male offspring, which was associated with changes in cytokine levels. In contrast to F3 BPA males, LowerB and UpperB female offspring had comparable body weight, glucose tolerance and insulin secretion as Controls. Thus, maternal BPA exposure resulted in fewer metabolic defects in F3 than F1 and F2 offspring, and these were sex- and dose-specific.

Chronic exposure of Hawaii Island spinner dolphins (Stenella longirostris) to human activities.

Habitat selection is strongly influenced by spatial variations in habitat quality and predation risk. Repeated exposure of wildlife to anthropogenic activities in important habitats may affect habitat selection, leading to negative biological consequences. We quantified the cumulative human exposure of a small, genetically isolated and behaviourally constrained spinner dolphin (Stenella longirostris) population, off Hawaii Island, and exposure effects on their daytime cumulative activity budget. Dolphins were exposed to human activities within 100 m for 82.7% of the daytime, with a median duration of 10 min between exposure events. Individual dolphins spent on average 61.7% (s.d. = 6.5) of their daytime resting. Of their total rest time, greater than 90% occurred inside sheltered bays. Despite high levels of human exposure, we did not observe an effect on dolphin resting behaviour. The short intervals between exposure events probably prevent dolphins from returning to a natural resting state before the next event. Consequently, ‘control’ observations may represent a resting behaviour of a more vigilant nature. Chronic levels of exposure to human activities could lead to rest deprivation, displacement from preferred resting habitats and ultimately negative population level effects. These results have implications for new proposed legislation aiming to reduce dolphin exposure to human activities.

German Environmental Specimen Bank (ESB): Time Trends of Paraben Exposure

Parabens are used as preservatives e.g. in cosmetics and body care products. They have allergenic and estrogenic properties. According to the European Scientific Committee on Consumer Products (SCCP) the toxicological data available for isopropyl-, isobutyl-, pentyl-, benzyl- and phenyl-paraben do not allow for the assessment of their health impact. Therefore, since 2014, these parabens are prohibited in cosmetic products in Europe (Commission Regulation (EU) No 358/201): For n-propyl- and n-butyl-parabene the maximum percentage was reduced to 0.19% (0.14% as acid) for each compound.Internal exposure time trends for young adults aged 20 to 29 years were analyzed in 24 h-urine samples collected by the ESB for 6 parabens (methyl-, ethyl-, iso-propyl, n-propyl, iso-butyl, and n-butyl-paraben), covering the period from 1995 to 2017. Parabens were determined after enzymatic hydrolysis via HPLC-MS/MS. The limit of quantification (LOQ) was 0.5 µg/L.In 1995 10% of the samples contained isobutyl-paraben levels above LOQ. As a maximum, a fraction of 30% was observed in 2007 and 2008. In 2017 it was found in none of the samples. The fraction of levels at or above LOQ for n-butyl-paraben decreased from 27% in 1995 to 5% in 2017 (2004: 53 %). Although the use of ethyl-paraben had been classified as acceptable by the SCCS, exposure slightly decreased: The fraction of levels at or above LOQ decreased from 85% in 1995 to 67% in 2017. Methyl-paraben was detected in all samples analysed. Apart from decreasing detection rates urinary concentrations started to drop considerably in recent years for all parabens.For further elucidating the trend, similar studies in other European countries are warranted. The decline in exposure can be considered a positive result from a precautionary standpoint. However, health based guidance values are needed for substantiated evaluation of human exposure levels.

Employing Dietary Comparators to Perform Risk Assessments for Anti-Androgens Without Using Animal Data.

This study investigated the use of androgen receptor (AR) reporter gene assay data in a non-animal exposure-led risk assessment in which in vitro anti-androgenic activity and exposure data were put into context using a naturally occurring comparator substance with a history of dietary consumption. First, several dietary components were screened to identify which selectively interfered with AR signaling in vitro, using the AR CALUX® test. The IC50 values from these dose-response data together with measured or predicted human exposure levels were used to calculate exposure: activity ratios (EARs) for the dietary components and a number of other well-known anti-androgenic substances. Both diindolylmethane (DIM) and resveratrol are specifically acting dietary anti-androgens. The EARs for several anti-androgens were therefore expressed relative to the EAR of DIM, and how this ‘dietary comparator ratio’ (DCR) approach may be used to make safety decisions was assessed using an exposure-led case study for an anti-androgenic botanical ingredient. This highlights a pragmatic approach which allows novel chemical exposures to be put into context against dietary exposures to natural anti-androgenic substances. The DCR approach may have utility for other modes of action where appropriate comparators can be identified.

The potential human exposure to antibiotic resistant-Escherichia coli through recreational water

It is important that bathing water sites are free as possible from antibiotic resistant bacteria (ARB) to prevent the spread of difficult to treat infections throughout the population. This study examines the possible human exposure to antibiotic resistant Escherichia coli (AR-E. coli) through recreational activities at two different bathing water sites located near wastewater treatment plants (WWTPs). A quantitative risk assessment model was created to model the pathway of the AR-E. coli from the WWTPs effluent water through to the bathing water sites. Both sampling data and data from scientific literature were used. The main steps considered for the model were: the dilution and decay of the AR-E. coli from the WWTPs effluent water into the river; the dilution of the river into the bathing water sites and the human exposure to AR-E. coli through recreational activities at the bathing water sites (as a result of water ingestion). The results show the mean predicted human exposure levels ranged between 0.45 and 345.09 cfu/100 ml. A back calculation method determined that in accordance with the European Bathing Water Directive (2006/7/EC) (BWD) to be considered “poor” water quality, the concentration of AR-E. coli in WWTP effluent water would need to exceed 2.45 log cfu/ml at site 1 and exceed 2.71 log cfu/ml at site 2. This study provides valuable information for regulatory bodies and policy makers on the possible human exposure levels to AR-E. coli and the maximum permissible concentrations in WWTP effluent water to ensure compliance with relevant bathing water legislation.

Headspace In-Tube Microextraction and GC-ICP-MS Determination of Mercury Species in Petroleum Hydrocarbons

Characterization of mercury contamination in petroleum hydrocarbons (PHs) is necessary in order to assess the risk of corrosion of the processing infrastructure and to assess the level of human exposure to Hg-containing substances. Here we present an accurate and sensitive method for determination of Hg species in PHs by headspace sampling with a possibility of on-line pre-concentration using in-tube extraction (ITEX) combined with gas chromatography–inductively coupled plasma mass spectrometry (GC-ICP-MS) analysis. Mercury species were first extracted from the PHs matrix into an aqueous phase via dithizone chelation and subsequently converted with sodium tetrapropyl borate into volatile derivatives which could be sampled from the headspace prior to GC-ICP-MS analysis. For concentrations in the ng kg–1 range, the on-line ITEX method was applied, whereas the μg kg–1 range was accessible by static headspace. Quantitation of Hg species was carried out by a double isotope dilution method, with quantitative recoveries of methylmercury (MeHg, average 101 ± 5%) and inorganic mercury (InHg, average 97 ± 7%) by direct headspace injection. Average recoveries of Hg spikes after on-line ITEX pre-concentration were 95 ± 3% for MeHg and 98 ± 8% for InHg. The detection limits for MeHg and InHg were 428 and 46 ng kg–1 when measured by static headspace, and 2.4 ng kg–1 and 1.7 ng kg–1 by on-line ITEX pre-concentration. The accuracy of the pre-concentration method was demonstrated by analysis of a crude oil standard reference material (NIST 2722) certified for InHg.

Pharmaceuticals and endocrine disruptors in raw and cooked seafood from European market: Concentrations and human exposure levels

Pharmaceuticals (PhACs) and endocrine disrupting compounds (EDCs) are chemicals of emerging concern that can accumulate in seafood sold in markets. These compounds may represent a risk to consumers through effects on the human reproductive system, metabolic disorders, pathogenesis of breast cancer or development of microbial resistance. Measuring their levels in highly consumed seafood is important to assess the potential risks to human health. Besides, the effect of cooking on contaminant levels is relevant to investigate. Therefore, the objectives of this research were to study the presence and levels of PhACs and EDCs in commercially available seafood in the European Union market, to investigate the effect of cooking on contaminant levels, and to evaluate the dietary exposure of humans to these compounds through seafood consumption. A sampling survey of seafood from 11 European countries was undertaken. Twelve highly consumed seafood types were analysed raw and cooked with 3 analytical methods (65 samples, 195 analysis). PhACs were mostly not detectable or below quantification limits in seafood whereas EDCs were a recurrent group of contaminants quantified in the majority of the samples. Besides, cooking by steaming significantly increased their levels in seafood from 2 to 46-fold increase. Based on occurrence and levels, bisphenol A, methylparaben and triclosan were selected for performing a human exposure assessment and health risk characterisation through seafood consumption. The results indicate that the Spanish population has the highest exposure to the selected EDCs through seafood consumption, although the exposure via seafood remained below the current toxicological reference values.

Paternal Bisphenol A Exposure Alters Offspring Glucose Tolerance in a Time, Dose, and Sex-Specific Manner

As it is becoming increasingly accepted that maternal exposure to the ubiquitous environmental pollutant bisphenol A (BPA) predisposes offspring to metabolic impairments, paternal contribution in this context remains unresolved. To investigate a relationship between paternal BPA exposure and offspring obesity and glucose tolerance, a mouse model was developed using dietary BPA exposure at doses comparable to human exposure levels (7% Corn Oil diet (Control), 10 μg/mg/day (Lower BPA), and 10 mg/kg/day (Upper BPA)). Two exposure windows were investigated: 1) direct exposure of male mice beginning at sexual maturation (5 weeks of age) and continuing for 12 weeks prior to mating, and 2) in utero exposure, in which dams were exposed beginning 2 weeks prior to mating and ending at weaning. F1 males were sired to unexposed females. At 16 weeks of age, offspring from both exposure windows underwent body composition analysis via NMR or DEXA scan as well as glucose tolerance testing. Paternal BPA exposure during adulthood did not affect body weight, adiposity or glucose tolerance in offspring. In utero-exposed sires produced offspring that also had no changes in body weight or adiposity. However, female offspring from the Lower BPA dose were glucose intolerant. Females with glucose intolerance were selected for islet perifusion, and interestingly, those females from Lower BPA dose exhibited enhanced glucose-stimulated insulin secretion compared to controls indicating insulin resistance. These data demonstrate that while paternal BPA exposure after sexual maturity may be metabolically innocuous, paternal BPA exposure during gestation and lactation precipitates sex-specific impairments in glucose tolerance. Further studies are required to describe precisely the glucose homeostatic impairment and elucidate epigenetic changes in sperm associated with phenotypic transmission. Disclosure C.S. Rashid: None. A. Bansal: None. R.A. Simmons: None.

The occurrence of home and personal care products in the Haihe River catchment and estimation of human exposure

A sub-catchment of the Haihe River basin goes through the Beijing-Tianjin region with a population of 26 million, therefore, the use and release of home and personal care product ingredients (HPCPs) to the river catchment could be potentially substantial. Many HPCPs have been shown to be toxic to human and animals. So, it is essential to know the exposure level of HPCPs in the river basin. The average concentrations of five preservatives, three disinfectants and an antioxidant were found to be 398, 352 and 77.7 ng L−1, respectively, in the dry season. The chemical concentrations in the effluents of wastewater treatment plants (WWTPs) and untreated wastewater discharge were respectively ca. 1.3–2.2 and 1.6–7.5 times higher than those in river water. The mass flux of ∑HPCPs has been estimated to be 8.7 g/h at the outfall of the Shahe Reservoir and 181 g/h and 214 g/h at the estuary of the Haihe River and Yongdingxin River to Bohai Bay, respectively. The attenuation of ∑HPCPs was over 79% along the Wenyu River. By using the backward method, the estimated average loadings to WWTPs ranged from 0.51 to 2.0 mg/day/cap for the various individual compounds. They were 1–3 orders of magnitude higher than the estimation from the forward calculation for parabens. This indicates the possible underestimation of chemical usage and human exposure levels by the current published studies or the probably additional industrial release to the target catchment. Such a study provides useful information for the development of chemical management approaches and indicates that further research is needed to improve the estimation of HPCPs usage and emissions to aquatic environment.

Quantification and feed to food transfer of total and inorganic arsenic from a commercial seaweed feed

Seaweed has a long-associated history of use as a supplemented livestock feed, providing nutrients and vitamins essential to maintaining animal health. Some species of seaweed, particularly the fucoids, are well-known accumulators of the metalloid arsenic (As). Arsenic toxicity to humans is well established even at low exposure levels and is considered a class 1 human carcinogen. As mankind's appetite for livestock produce continues to grow unabated, there is a concern that consumption of livestock produce reared on a diet supplemented with seaweed animal feed (SAF) may pose a threat to the human population due to potentially high levels of As present in seaweed. To address this concern and provide end users, including industry, consumers, policymakers and regulators with information on the exposure associated with As in commercial seaweed animal feed, the estimated daily intake (EDI) of As was calculated to evaluate potential human exposure levels. Using As data from a commercially available seaweed meal over a five-year period (2012–2017) a population exposure assessment was carried out. A Monte Carlo simulation model was developed to characterise the feed to food transfer of As from animal feed to animal produce such as beef, milk, chicken, and eggs. The model examined initial levels in seaweed, inclusion rate in animal feed, animal feeding rates and potential transfer to food produced from a supplemented diet of SAF. The analysis of seaweed animal feed showed that inorganic As was a small fraction of the total As found in seaweed meal (80:1). Statistical analysis found significant differences in the concentration of As in seaweed animal feed depending on the grain size (p < 0.001), with higher As concentrations in smaller sized grain fractions. Due to several detoxification steps and subsequent rapid excretion from the bodies of livestock, a very low carryover rate of As compounds from seaweed animal feed into livestock produce was observed. The EDI calculated in this study for the livestock produce evaluated at the 95th confidence interval was <0.01% of suggested safe levels of inorganic As intake. The threat to the general population as a result of consumption of livestock products reared on a diet consisting of SAF is found to be negligible.

Laser Irradiation of Organic Tattoo Pigments Releases Carcinogens with 3,3′-Dichlorobenzidine Inducing DNA Strand Breaks in Human Skin Cells

Laser Irradiation of Organic Tattoo Pigments Releases Carcinogens with 3,3′-Dichlorobenzidine Inducing DNA Strand Breaks in Human Skin Cells

Food-grade TiO2 is trapped by intestinal mucus in vitro but does not impair mucin O-glycosylation and short-chain fatty acid synthesis in vivo: implications for gut barrier protection

BackgroundTitanium dioxide (TiO2) particles are commonly used as a food additive (E171 in the EU) for its whitening and opacifying properties. However, the risk of gut barrier disruption is an increasing concern because of the presence of a nano-sized fraction. Food-grade E171 may interact with mucus, a gut barrier protagonist still poorly explored in food nanotoxicology. To test this hypothesis, a comprehensive approach was performed to evaluate in vitro and in vivo interactions between TiO2 and intestinal mucus, by comparing food-grade E171 with NM-105 (Aeroxyde P25) OECD reference nanomaterial.ResultsWe tested E171-trapping properties of mucus in vitro using HT29-MTX intestinal epithelial cells. Time-lapse confocal laser scanning microscopy was performed without labeling to avoid modification of the particle surface. Near-UV irradiation of E171 TiO2 particles at 364 nm resulted in fluorescence emission in the visible range, with a maximum at 510 nm. The penetration of E171 TiO2 into the mucoid area of HT29-MTX cells was visualized in situ. One hour after exposure, TiO2 particles accumulated inside “patchy” regions 20 µm above the substratum. The structure of mucus produced by HT29-MTX cells was characterized by MUC5AC immunofluorescence staining. The mucus layer was thin and organized into regular “islands” located approximately 20 µm above the substratum. The region-specific trapping of food-grade TiO2 particles was attributed to this mucus patchy structure. We compared TiO2-mediated effects in vivo in rats after acute or sub-chronic oral daily administration of food-grade E171 and NM-105 at relevant exposure levels for humans. Cecal short-chain fatty acid profiles and gut mucin O-glycosylation patterns remained unchanged, irrespective of treatment.ConclusionsFood-grade TiO2 is trapped by intestinal mucus in vitro but does not affect mucin O-glycosylation and short-chain fatty acid synthesis in vivo, suggesting the absence of a mucus barrier impairment under “healthy gut” conditions.

Exposure to Bisphenol A, Bisphenol F, and Bisphenol S in U.S. Adults and Children: The National Health and Nutrition Examination Survey 2013-2014.

Bisphenol F (BPF) and bisphenol S (BPS) are replacing bisphenol A (BPA) in the manufacturing of products containing polycarbonates and epoxy resins. Data on current human exposure levels of these substitutes are needed to aid in the assessment of their human health risks. This study analyzed urinary bisphenol levels in adults (N = 1808) and children (N = 868) participating in the National Health and Nutrition Examination Survey (NHANES) 2013–2014 and investigated demographic and lifestyle factors associated with urinary levels of bisphenols. BPA, BPS, and BPF were detected in 95.7, 89.4, and 66.5% of randomly selected urine samples analyzed as part of NHANES 2013–2014, respectively. Median levels of BPA in U.S. adult were higher (1.24 μg/L) than BPF and BPS levels (0.35 and 0.37 μg/L, respectively). For children, median BPA levels were also higher (1.25 μg/L) than BPF and BPS levels (0.32 and 0.29 μg/L, respectively). The limits of detection for BPA, BPF, and BPS were 0.2, 0.2, and 0.1 μg/L, respectively. Urinary levels showed associations with gender, race/ethnicity, family income, physical activity, smoking, and/or alcohol intake that depended on the specific bisphenol. The results of this study indicate that exposure of the general U.S. population to BPA substitutes is almost ubiquitous. Because exposures differ across the U.S. population, further studies of environmental, consumer, and lifestyle factors affecting BPF and BPS exposures are warranted.

An electrochemical Bisphenol F sensor based on ZnO/G nano composite and CTAB surface modified carbon paste electrode architecture.

Due to the enforcement of regulatory restrictions to prevent risk to human health from Bisphenol A (BPA), its structural analogue Bisphenol F (BPF) has been introduced into the market as an alternative. But however recent studies describe BPF as an effectual endocrine disruptor. Hence, there is an indispensible need for research concerning BPF human and environmental exposure level. In this work, we have elicited the development of an economical electrochemical sensor, to quantify and investigate in detail the electrochemical behavior of BPF using carbon paste electrode (CPE) modified with zinc oxide reduced graphene nanocomposite (ZnO/G) and cetyltrimethylammonium bromide (CTAB). The ZnO/G was synthesized using Hummers method and characterized by spectroscopic techniques. Under optimal conditions, conductive and biocompatible ZnO/G/CTAB/MCPE offered ultra sensitivity for BPF recognition by Differential Pulse Voltammetry (DPV), with a detection limit of 0.06 μM. Lowering of activation energy for electro-oxidation of BPF and absence of peak for interfering molecule Ascorbic acid (AA) makes it an unique sensor for the detection of BPF with significant analytical advantage over other electrodes reported in literature. Versatility of the electrode was demonstrated by applying it to real time analysis of human body fluids, canned beverage and different water samples fortified with BPF. The satisfactory recoveries obtained, consequently authenticates the practicality of the proposed sensor.

Mice exposed to bisphenol A exhibit depressive-like behavior with neurotransmitter and neuroactive steroid dysfunction

Fetal exposure to endocrine disrupting chemicals (EDCs) has been associated with adverse neurobehavioral outcomes across the lifespan and can persist across multiple generations of offspring. However, the underlying mechanisms driving these changes are not well understood. We investigated the molecular perturbations associated with EDC-induced behavioral changes in first (F1) and second (F2) filial generations, using the model EDC bisphenol A (BPA). C57BL/6J dams were exposed to BPA from preconception until lactation through the diet at doses (10 μg/kg bw/d-lower dose or 10 mg/kg bw/d-upper dose) representative of human exposure levels. As adults, F1 male offspring exhibited increased depressive-like behavior, measured by the forced swim test, while females were unaffected. These behavioral changes were limited to the F1 generation and were not associated with altered maternal care. Transcriptome analysis by RNA-sequencing in F1 control and upper dose BPA-exposed adult male hippocampus revealed neurotransmitter systems as major pathways disrupted by developmental BPA exposure. High performance liquid chromatography demonstrated a male-specific reduction in hippocampal serotonin. Administration of the selective serotonin reuptake inhibitor fluoxetine (20 mg/kg bw) rescued the depressive-like phenotype in males exposed to lower, but not upper, dose BPA, suggesting distinct mechanisms of action for each exposure dose. Finally, high resolution mass spectrometry revealed reduced circulating levels of the neuroactive steroid dehydroepiandrosterone in BPA-exposed males, suggesting another potential mechanism underlying the depressive-like phenotype. Thus, behavioral changes associated with early life BPA exposure may be mediated by sex-specific disruptions in the serotonergic system and/or sex steroid biogenesis in male offspring.