Impact of chronic sub-lethal methylparaben exposure on cardiac hypoxia and alterations in neuroendocrine factors in zebrafish model.

BACKGROUND: Endocrine-disrupting chemicals have been shown to cause toxicity in different systems of the body including the endocrine, cardiovascular and nervous systems. This study aims to analyze the adverse effects of Methylparaben (MP) on cardiac functions, neurodevelopment, and behavior of zebrafish. METHODS AND RESULTS: Adult male and female zebrafish were exposed to MP for 30 days to study the toxicity effects. Zebrafish were grouped into control, solvent control, 1/10th (110 ppb), 1/100th, and 1/1000th (1 ppb) lethal concentration 50 of MP. Neurobehavioral assays, acetylcholinesterase (AChE) activity, serotonin levels, and expression of genes-Hypoxia-inducible factor 1 alpha, Neurotrophic Receptor Tyrosine Kinase, Paired box protein Pax-6, and tnnt2 were investigated in zebrafish. Results of the study showed more anxiety-like behavior in MP-treated female zebrafish when compared to males on chronic exposure. There was a dose-dependent reduction of AChE activity in both male and female zebrafish. Female zebrafish showed a dose-dependent increase in serotonin level on MP exposure while male zebrafish showed a dose-independent decrease in serotonin level. On MP exposure, there was also a dose-dependent dysregulation in the expression of cardiac hypoxia and neuronal differentiation-related genes in female zebrafish while a dose-independent change was observed in male zebrafish. CONCLUSION: Chronic MP exposure affects cardiac functions, neuronal functions, and behavior of zebrafish by exhibiting changes in AChE activity, serotonin levels, and altering the expression of genes related to cardiac hypoxia and neuronal differentiation even at sub-lethal doses.

The potential implications of estrogenic and antioxidant-dependent activities of high doses of methyl paraben on MCF7 breast cancer cells.

Methyl paraben (MP) is an endocrine-disrupting compound that possesses estrogenic properties and contributes to an aberrant burden of estrogen signaling in the human breast and subsequently increasing the risks for the development of breast cancer. The exact exposure, as well as the safe concentrations, are variable among daily products. The present study addresses the effects of exposure to escalated concentrations of MP on the proliferation of MCF-7 breast cancer cells in addition to exploring its other mechanisms of action. The study involved exposure of cultured MCF-7 breast cancer cells to seven MP concentrations, ranging from 40 to 800 µM for 5 days. Cell viability, apoptosis, and proliferation were respectively assessed using crystal violet test, flow cytometric analysis, and quantitative real-time polymerase chain reaction for Ki-67 expression. The estradiol (E2) secretion and oxidative stress were also assessed and analyzed in correlation to MP's proliferation and cytotoxicity potentials. The results showed that the maximum proliferative concentration of MP was 800 µM. At a concentration of 40 µM and higher, MP induced increased expression of Ki-67, denoting enhanced proliferation of the cells in monolayer culture. A positive correlation between the detrimental oxidative stress effect of MP's tested concentrations, cell proliferation, and viability was demonstrated (p < 0.05). Our results indicated that MP at high doses induced sustained cell proliferation due to E2 secretion as well as its antioxidant activity. Accordingly, it was concluded that high and unpredicted exposure to MP might carry a carcinogenic hazard on estrogen receptor-positive breast cancer cells.

Investigation of combined effects of propyl paraben and methyl paraben on the hypothalamic-pituitary-adrenal axis in male rats.

The aim of this study was to investigate the endocrine-disrupting effects of methyl paraben (MeP) and propyl paraben (PrP) mixture on the hypothalamic-pituitary-adrenal axis (HPA). In this study, six experimental groups were designated. These groups included three control groups (control, corn oil control, and positive control (50 mg/kg/day BPA)) and three dose groups (10, 100, and 500 mg/kg/day MeP+PrP). MeP with PrP were mixed in a 1:1 ratio and administered to the 42-day-old male rats by oral gavage for 30 days. At the end of the experiment, adrenocorticotropic hormone (ACTH), corticosterone and aldosterone hormones were analyzed in serum. Effects of MeP+PrP on the adrenal glands were investigated by immunohistochemical staining of 11ß hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) enzymes involved in the synthesis steps of corticosterone and aldosterone. Also, pituitary and adrenal glands were examined histopathologically. In the histopathological findings, cortical nodule, congestion, and edema were found in the tissues. In the pituitary gland, cytokeratin rings were detected in all MeP+PrP dose groups, supporting the increase of corticosterone and ACTH. Serum corticosterone, aldosterone, and ACTH hormone levels were increased in the 100 mg/kg/day MeP+PrP and BPA groups. Results obtained from immunohistochemical staining showed that increased staining parallelled increased corticosterone and aldosterone hormone levels. In summary, the results showed that exposure to the MeP+PrP mixture caused a significant increase in ACTH and corticosterone. Also, the MeP+PrP mixture caused a significant increase of CYP11B1 and CYP11B2. MeP+PrP exposure disrupts the normal HPA axis.

Methyl Paraben and Carbamazepine in Water and Striped Catfish (Pseudoplatystoma magdaleniatum) in the Cauca and Magdalena Rivers.

Between 2017 and 2019, samplings were carried out in the San Jorge, Cauca and Magdalena River basins in Colombia, to determine the presence of methyl paraben and carbamazepine in water and Pseudoplatystoma magdaleniatum. For the analysis of the samples, a validation of the analytical method was performed, following the EPA method 1694 (Pharmaceutical and personal care products in water), with slight modifications. This was done by liquid-chromatography tandem mass spectrometry, for quantification of methyl paraben and carbamazepine, including parameters of linearity, accuracy precision and veracity. Carbamazepine was found in the Magdalena River at 8.03 ± 0.01 µg/L in transition season. In fish samples, methyl paraben and carbamazepine were detected in a range between 32 and 90.80 µg/kg in transition and dry seasons.

Contamination and spatial distribution of parabens, their metabolites and antimicrobials in sediment from Korean coastal waters.

Synthetic antimicrobials known as parabens, triclosan (TCS), and triclocarban (TCC) are emerging environmental contaminants. Limited studies on these contaminants have been conducted in coastal environments. In our study, parabens, their metabolites, TCS, and TCC were measured in sediment collected along the Korean coast, to investigate contamination status, spatial distribution, and potential health risks to coastal environments. Methyl paraben and 4-hydroxybenzoic acid were detected in all sediment samples, suggesting widespread contamination. Total concentrations of parent parabens, their metabolites, TCS, and TCC ranged from 0.19 to 11.2 (mean: 2.40) ng/g dry weight, 9.65 to 480 (mean: 120) ng/g dry weight, and < limit of quantification (LOQ)-6.10 (mean: 0.41) ng/g dry weight, and from < LOQ-41.0 (mean: 2.78) ng/g dry weight, respectively. The overall contamination of parabens and antimicrobials in sediment was different from that reported for persistent organic pollutants due to different contamination sources among chemical groups. Significant correlation was found among target contaminants in sediment, suggesting the existence of a common source. Total organic carbon (TOC) was significantly correlated with the concentrations of target contaminants, implying a major factor for coastal distribution of parabens and antimicrobials. The concentrations of parabens and TCS measured in sediment did not exceed a hazard quotient (HQ), implying low potential health risks associated with exposure to these contaminants. This is the first study to report the nationwide distribution of parabens, their metabolites, and antimicrobials in the coastal environments of Korea.

A New Sensor for Methyl Paraben Using an Electrode Made of a Cellulose Nanocrystal-Reduced Graphene Oxide Nanocomposite.

A new cellulose nanocrystal-reduced graphene oxide (CNC-rGO) nanocomposite was successfully used for mediatorless electrochemical sensing of methyl paraben (MP). Fourier-transform infrared spectroscopy (FTIR) and field-emission scanning electron microscopy (FESEM) studies confirmed the formation of the CNC-rGO nanocomposite. Cyclic voltammetry (CV) studies of the nanocomposite showed quasi-reversible redox behavior. Differential pulse voltammetry (DPV) was employed for the sensor optimization. Under optimized conditions, the sensor demonstrated a linear calibration curve in the range of 2 × 10-4-9 × 10-4 M with a limit of detection (LOD) of 1 × 10-4 M. The MP sensor showed good reproducibility with a relative standard deviation (RSD) of about 8.20%. The sensor also exhibited good stability and repeatability toward MP determinations. Analysis of MP in cream samples showed recovery percentages between 83% and 106%. Advantages of this sensor are the possibility for the determination of higher concentrations of MP when compared with most other reported sensors for MP. The CNC-rGO nanocomposite-based sensor also depicted good reproducibility and reusability compared to the rGO-based sensor. Furthermore, the CNC-rGO nanocomposite sensor showed good selectivity toward MP with little interference from easily oxidizable species such as ascorbic acid.

Phototoxicity and chronic toxicity of methyl paraben and 1,2-hexanediol in Daphnia magna.

Parabens are used as antimicrobial preservatives in consumer products. Exposure to methylparaben (MP) has been associated with adverse health outcomes, therefore, an alternative compound, 1,2-hexanediol (1,2-H), has been applied for cosmetics. In the present study, the phototoxicity of MP and 1,2-H, as well as the toxic effect caused by chronic exposure, were investigated using Daphnia magna. The 48 h acute toxicity tests with D. magna were conducted under indoor or ultraviolet (UV) light irradiation conditions, i.e., exposure to 4 h/d sunlight. Changes in the transcription of genes related to oxidative stress were determined in D. magna juveniles, to investigate the underlying mechanism of phototoxicity. The 21 d chronic toxicity tests of MP and 1,2-H were performed under indoor light irradiation. Exposure to MP under environmental level of UV light was more detrimental to D. magna. Transcripts of catalase and glutathione-S-transferase genes in D. magna was significantly increased by co-exposure to MP and UV light. After 21 d of chronic exposure to MP and 1,2-H, the reproduction no-observed effect concentrations for D. magna were 1 and >10 mg/L, respectively. The present study showed that exposure to UV could magnify the toxicity of MP on daphnids. Although acute and chronic toxicities of 1,2-H were generally lower than those of MP, its effects on other aquatic organisms should not be ignored. Further studies are needed to identify other mechanisms of MP phototoxicity.

A fast and direct spectrophotometric method for the simultaneous determination of methyl paraben and hydroquinone in cosmetic products using successive projections algorithm.

OBJECTIVE: To develop a simple and efficient spectrophotometric technique combined with chemometrics for the simultaneous determination of methyl paraben (MP) and hydroquinone (HQ) in cosmetic products, and specifically, to: (i) evaluate the potential use of successive projections algorithm (SPA) to derivative spectrophotometric data in order to provide sufficient accuracy and model robustness and (ii) determine MP and HQ concentration in cosmetics without tedious pre-treatments such as derivatization or extraction techniques which are time-consuming and require hazardous solvents. METHODS: The absorption spectra were measured in the wavelength range of 200-350 nm. Prior to performing chemometric models, the original and first-derivative absorption spectra of binary mixtures were used as calibration matrices. Variable selected by successive projections algorithm was used to obtain multiple linear regression (MLR) models based on a small subset of wavelengths. The number of wavelengths and the starting vector were optimized, and the comparison of the root mean square error of calibration (RMSEC) and cross-validation (RMSECV) was applied to select effective wavelengths with the least collinearity and redundancy. Principal component regression (PCR) and partial least squares (PLS) were also developed for comparison. The concentrations of the calibration matrix ranged from 0.1 to 20 µg mL(-1) for MP, and from 0.1 to 25 µg mL(-1) for HQ. The constructed models were tested on an external validation data set and finally cosmetic samples. RESULTS: The results indicated that successive projections algorithm-multiple linear regression (SPA-MLR), applied on the first-derivative spectra, achieved the optimal performance for two compounds when compared with the full-spectrum PCR and PLS. The root mean square error of prediction (RMSEP) was 0.083, 0.314 for MP and HQ, respectively. To verify the accuracy of the proposed method, a recovery study on real cosmetic samples was carried out with satisfactory results (84-112%). CONCLUSION: The proposed method, which is an environmentally friendly approach, using minimum amount of solvent, is a simple, fast and low-cost analysis method that can provide high accuracy and robust models. The suggested method does not need any complex extraction procedure which is time-consuming and requires hazardous solvents.

Exposure assessment of dairy cows to parabens using hair samples analysis.

Parabens (PBs) are used as preservatives in various products. They pollute the environment and penetrate living organisms, showing endocrine disrupting activity. Till now studies on long-term exposure of farm animals to PBs have not been performed. Among matrices using in PBs biomonitoring hair samples are becoming more and more important. During this study concentration levels of methyl paraben (MeP), ethyl paraben (EtP), propyl paraben (PrP) butyl paraben (BuP) and benzyl paraben (BeP) were evaluated using liquid chromatography-mass spectrometry (LC-MS) in hair samples collected from dairy cows bred in the Kyrgyz Republic. MeP was noted in 93.8% of samples (with mean concentration levels 62.2 ± 61.8 pg/mg), PrP in 16.7% of samples (12.4 ± 6.5 pg/mg) and EtP in 8.3% of samples (21.4 ± 11.9 pg/mg). BuP was found only in one sample (2.1%) and BeP was not detected in any sample included in the study. Some differences in MeP concentration levels in the hair samples depending on district, where cows were bred were noted. This study has shown that among PBs, dairy cows are exposed mainly to MeP, and hair samples may be a suitable matrix for research on PBs levels in farm animals.

Human serum paraben levels and their associations with rheumatoid arthritis: a case-control study from Hangzhou, China.

Parabens are widely used in consumer products resulting in frequent exposure to humans. To date, little is known about the association between human paraben exposure and rheumatoid arthritis (RA). In this study, a case-control study (n = 290) was conducted in Hangzhou, China, aiming to quantify the concentrations of methyl paraben (MeP), ethyl paraben (EtP), propyl paraben (PrP), and butyl paraben (BuP) in serum samples and to determine their associations with RA risks. MeP (mean 4.7 ng/mL, range <0.05-20 ng/mL) was the predominant paraben in human serum, followed by PrP (1.9 ng/mL, <0.12-24 ng/mL), EtP (1.4 ng/mL, <0.09-10 ng/mL), and BuP (1.09 ng/mL, <0.10-10 ng/mL). With 1-unit increase of MeP concentrations in human serum, the levels of rheumatoid factors, anticyclic citrullinated peptide antibody, and immunoglobulin G will increase by 0.19 unit (95% confidence intervals [CI]: 0.12-0.46), 0.30 unit (95% CI: 0.26-0.58), and 0.24 unit (95% CI: 0.21-0.30) in the adjusted model, respectively. One-unit increase of MeP and PrP concentrations in human serum was associated with an increase of 0.15 (95% CI: 0.037-0.28) and 0.20 (95% CI: 0.10-0.32) in the C-reactive protein concentrations. In addition, an association between serum MeP levels and the incidence of RA (odds ratios (OR)crude = 1.33, CI: 1.11-1.62, p = 0.03; ORadjusted = 1.86, CI: 1.32-2.63, p = 0.02) was positive and significant. Based on the measurements of serum paraben concentrations, this work supports the evidence for the significant associations among paraben exposure, change of specific immune marker, and RA risks.

Different isoforms of parabens into marine environment: Biological effects on the bacterium Aliivibrio fischeri and the marine mussel Mytilus galloprovincialis.

Different isoforms of alkyl esters of p-Hydroxybenzoic acid, also known as parabens, are of great concern due to their widespread presence into the aquatic environment, their high concentrations in wastewater discharges, as well as their ability to induce adverse effects on aquatic organisms. Considering the imperative need for assessing their fate and risk to aquatic environment, the present study investigated the biological effects of two isoforms of parabens, methyl- (MeP) and propyl- (PrP), on the bacterium Aliivibrio fischeri (using the Bioluminescence Inhibition/Microtox® bioassay) and the mussel Mytilus galloprovincialis (in terms of mussel mortality, cellular, oxidative and genotoxic stress indices). The assessment of MeP and PrP behavior into aquatic media (artificial sea water/ASW and 2 % NaCl), primarily performed by UHPLC-UV-MS analysis, showed only a slight hydrolysis of PrP to 4-Hydrobenzoic acid (4-HBA). Furthermore, exposure of both species to different concentrations of each paraben revealed differences among their toxic potential, as well as their ability to cause cellular, oxidative and genotoxic effects on hemocytes of challenged mussels. Interestingly, the Microtox® bioassay showed that PrP mediated toxicity in A. fischeri were more pronounced than MeP, as revealed by the estimated toxic endpoints (in terms of concentration that promote 50 % of bioluminescence inhibition, EC50). Similarly, in challenged mussels, a significant disturbance of mussel hemocytes' lysosomal membrane integrity, as well as enhanced levels of superoxides, nitric oxides, lipid peroxidation byproducts, and micronuclei formation were observed. These findings are of great interest, since MeP and PrP differential toxic potential, as well their ability to induce pre-pathological alterations in marine species, like mussels, give new evidence for their risk to aquatic biota.

Associations between urinary parabens and lung cancer.

Parabens are a family of endocrine-disrupting chemicals. Environmental estrogens may play a vital role in the development of lung cancer. To date, the association between parabens and lung cancer is unknown. Based on the 189 cases and 198 controls recruited between 2018 and 2021 in Quzhou, China, we measured 5 urinary parabens concentrations and examined the association between urinary concentrations of parabens and lung cancer risk. Cases showed significantly higher median concentrations of methyl-paraben (MeP) (2.1 versus 1.8 ng/mL), ethyl-paraben (0.98 versus 0.66 ng/mL), propyl-paraben (PrP) (2.2 versus 1.4 ng/mL), and butyl-paraben (0.33 versus 0.16 ng/mL) than controls. The detection rates of benzyl-paraben were only 8 and 6% in the control and case groups, respectively. Therefore, the compound was not considered in the further analysis. The significant correlation between urinary concentrations of PrP and the risk of lung cancer (odds ratio (OR)adjusted = 2.22, 95% confidence interval (CI): 1.76, 2.75; Ptrend < 0.001) was identified in the adjusted model. In the stratification analysis, we found that urinary concentrations of MeP were significantly associated with lung cancer risk (OR = 1.16, 95% CI: 1.01, 1.27 for the highest quartile group). Besides, comparing the second, third, and fourth quartile groups with the lowest group of PrP, we also observed urinary PrP concentrations associated with lung cancer risk, with the adjusted OR of 1.52 (95% CI: 1.29, 1.65, Ptrend = 0.007), 1.39 (95% CI: 1.15, 1.60, Ptrend = 0.010), and 1.85 (95% CI: 1.53, 2.30, Ptrend = 0.001), respectively. MeP and PrP exposure, reflected in urinary concentrations of parabens, may be positively associated with the risk of lung cancer in adults.

Evaluation of new formulations for neutralizing antimicrobial preservatives in pharmaceutical preparations.

Background: Neutralization of preservative systems is essential to obtain reliable results when testing samples containing preservatives such as nutritional, cosmetic and pharmaceutical products. Therefore, the aim of this study was to prepare and investigate the neutralization ability of in-house neutralizing systems made of available cost-effective materials in the inactivation of preserved pharmaceutical suspensions. Ibuprofen and Cefpodoxime proxetil preserved suspensions were chosen as the quenching model since subsequent microbiological studies will be conducted on their local pharmaceutical formulations available in the Syrian market. Methods: We reported toxicity and efficacy ratios of ten neutralizing systems (No.1 to No.10) containing polysorbate 80, cetomacrogol 1000 and polyoxyl 40 hydrogenated castor oil with various concentrations dedicated to the inactivation of Ibuprofen and Cefpodoxime proxetil preserved suspensions, methyl paraben/propyl paraben mixture and sodium benzoate controls against low inoculum ranging between 1 × 102-1.2 × 103 CFU of five challenged bacteria and fungi; Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and another environmental isolate of Aspergillus niger. Neutralizing systems validation was conducted according to USP chapter 1227 criteria to assess the acceptance of recovery comparisons for both "Neutralizing systems toxicity test" and "Neutralizing systems efficacy test" which enabled determining the appropriate neutralizing formula for both neutralization of preservative system of a specified product and being non-toxic towards the challenged microorganism additions. Results: Most neutralizing formulas used in the study were non-toxic for all tested microorganisms. According to "Neutralizing systems efficacy test", No. 3 (polysorbate 80 (3%)) and No. 10 (polysorbate 80 (1%), cetomacrogol 1000 (1%) and polyoxyl 40 hydrogenated castor oil (1%)) effectively recovered at least three microorganisms when used in the neutralization of samples. Most limitations were observed when neutralizing ibuprofen suspension. However, we found neutralizing system No. 10 against Pseudomonas aeruginosa, No. 3 and No. 5 against Escherichia coli and No. 8 and No. 10 against Candida albicans were effective in the neutralization of ibuprofen suspension. All neutralizing systems effectively inactivated the preservative system of cefpodoxime proxetil suspension using all microorganisms while several neutralizing systems failed in quenching cefpodoxime proxetil suspension against Staphylococcus aureus. Conclusion: Due to the variation in the neutralization efficacy relative to the product sample and challenged microorganism, neutralization validation procedure must be undertaken before microbiological testing of pharmaceuticals which makes the development and validation of neutralizing systems an essential procedure.

Urinary paraben concentrations of adult women by fasting status: Comparison between Korea and the United States.

Personal care products (PCPs) are considered as a major source of paraben exposure; however, the dietary contribution is not well known. We compared the urinary levels of methyl-, ethyl-, and propyl-paraben (MeP, EtP, and PrP), and investigated their associations with fasting status and contacts with other potential exposure sources among Korea and the US adult women. A group of fasting, non-pregnant adult women (n = 469) was recruited from Seoul, Ansan/Incheon, and Jeju, Korea in 2015-2016, and their urine was measured for parabens. Non-fasting Korean women of matching age (25-45 years) were chosen from the Korean National Environmental Health Survey (KoNEHS) Cycle 3 (n = 579). For the US women, both fasting (n = 154) and non-fasting (n = 201) females were chosen from the NHANES 2015-2016 participants. In fasting Korean women, the urinary MeP, EtP, and PrP concentrations (median) were measured at 47.30, 17.90, and 2.30 ng/mL, respectively. Urinary EtP and PrP levels in fasting Korean women were significantly lower than those in non-fasting women (EtP and PrP median of 26.40 and 3.57 ng/mL). On average, the difference in urinary EtP levels by fasting status was greater among the highly exposed groups. In the US population, EtP levels were significantly lower (median ranged 1.55-1.80 ng/mL depending on fasting status), but MeP levels were higher (67.90-84.35 ng/mL) than those of the Korean population. When only fasting women were considered, the median EtP levels of Korean women were 11.5-fold greater than those of US women, suggesting that the non-dietary contributions of EtP exposure could not be ignored among Korean women. Regardless of fasting status, MeP and PrP were significantly correlated, and their urinary levels in fasting Korean women were correlated with the use of several personal care products. The major dietary and non-dietary sources that may explain EtP exposure in Korean women warrant further investigation.

Urinary parabens and their potential sources of exposure among Korean children and adolescents: Korean National Environmental Health Survey 2015-2017.

Parabens are used as a preservative in several consumer products including cosmetics, personal care products, and medicinal products. These chemicals have been suspected for estrogenicity and potential adverse endocrine outcomes in humans. For the first time, exposure profiles and potential sources of major parabens are investigated for a nationally representative population of children and adolescents of Korea. In addition, major determinants of urinary paraben levels were identified. For this purpose, the children, and adolescents (n = 2355, 3-18 years of age) who participated in the Korean National Environmental Health Survey cycle 3 (2015-2017) were studied. Adjusted multiple linear regression models were employed to investigate the relationships of several potential demographic and behavioral determinants of exposure, with the urinary levels of three parabens; methyl, ethyl, and propyl paraben. Methyl and propyl paraben levels of the Korean children and adolescents were comparable to those of the US, but the high exposure group (95th percentile) showed much higher levels of exposure. Moreover, urinary ethyl paraben levels are always higher than those of other countries. The uses of personal care products including liquid soaps, fragrance products, nail polish, or antiseptic products were significantly associated with urinary paraben levels. In addition, dietary sources such as fast food and canned food consumption were identified as major contributors to ethyl paraben levels. For methyl and propyl parabens, the use of fever medications and ointments were identified as major determinants of the exposure, especially among the younger children of 3-5 years of age. These observations are related to the Korean regulations that permit the use of the parabens as preservatives in foods and medications. The findings demonstrate that the exposure profile of parabens among Korean children are unique, and mitigation efforts for some parabens are required in Korea. Further studies are warranted to confirm the exposure sources of parabens and to develop mitigation measures among Korean children and adolescents.

Plasticisers and preservatives in commercial milk products: A comprehensive study on packages used in the Spanish market.

A comprehensive study on packaging used in commercially available milk products from Spanish markets has been presented. Concentrations of four phthalates, seven parabens and BPA were determined in forty-two milk products. Eleven brands and five types of packaging (metallic aluminium bag, carton, high-density polyethylene, metal pail and polyethylene terephthalate) were included in the study. BPA showed the lowest concentrations (8.3 pg/g f.w.), far below those of phthalates (6431 pg/g f.w.) and parabens (6234 pg/g f.w.). Metallic aluminium bags were the least migrating packaging (considering plasticisers and monomers) followed by HDPE bottles, in the case of phthalates. Parabens showed their highest concentrations for fresh-milk samples. Levels found were far below the specific migration limits established by the EU and the cumulative hazard index was lower than 1, indicating that adverse health effects were not expected. In general, the results found in Spanish samples were lower than those reported in other countries.

Environmental application of monolithic carbonaceous aerogels for the removal of emerging pollutants.

In this study, the performance of three commercial available monolithic carbonaceous aerogels (NQ30A, NQ60A and NQ80A) for the removal of different emerging pollutants, detected in water sources, was evaluated. More specifically, the removal of two pharmaceuticals (antipyrine and sulfamethoxazole) and an anti-fungal agent (methyl paraben), widely used in cosmetics, was studied. The NQ60A demonstrated the best adsorption characteristics and effectively adsorbed over 50 mg/g of the antipyrine and around 30 mg/g sulfamethoxazole and methyl paraben. The kinetic study of the adsorption process revealed that pseudo-first order kinetic model described very well the kinetic behaviour of the selected pollutants onto the NQ60A aerogel. After that, the regeneration of the loaded aerogel, with antipyrine alone and in presence of the other two contaminants, was evaluated. The regeneration was accomplished in two ways: (1) by using directly the loaded aerogels as cathode during the electro-Fenton treatment and (2) by its regeneration immersed in the bulk volume of electro-Fenton cell (boron doped diamond as anode and carbon felt as cathode). Both approaches can provide an effective removal of the pollutants inside the aerogel. In addition, the regenerated aerogel proved to maintain its adsorptive properties and can be successfully reused in successive cycles of adsorption-regeneration. On the basis of these promising results, it can be concluded that the proposed strategy based on aerogels adsorption and electro-Fenton regeneration is a suitable alternative for emerging pollutants removal from water streams.

Identification of novel paraben-binding peptides using phage display.

Parabens are alkyl esters of 4-hydroxybenzoic acid, which is derived from a family of synthetic esters of p-hydroxybenzoic acid. Among all the kinds of paraben, two parabens (methyl paraben, MP; and n-propyl paraben, PP) are the most generally used as preservatives in personal care products, such as cosmetics, pharmaceuticals, and food also, and are often presented together. However, a number of studies have reported that the toxicity of parabens affects the water environment, and human as well. This study utilized M13 phage display technology to provide easy, efficient, and relatively inexpensive methods to identify peptides that bind to MP and PP, respectively, to remove in wastewater. At first, biopanning was performed, to sort MP and PP specific binding phages, and three cases of experiment, including negative control (NC), which could sort unspecific binding phage, were conducted at the same time. Phage binding affinity tests were substituted by concentration reduction using antibody conjugated magnetic beads, and paraben concentration was measured by HPLC. Analysis showed that the MP concentration reduction of 38% was the highest in M4 phage, while the PP concentration reduction of 44% was the highest in P3 phage. We successfully screened two peptides specific to MP and PP, namely, MP4 and PP3, respectively; the results showed that the MP concentration reduction in MP4 was the highest at 44%, and the PP concentration reduction in PP3 was the highest at 39%, and their specificity was measured by the capture rate between target and control. In conclusion, the phage display technique shows applicability to the removal of parabens in water; furthermore, it also shows the possibility of the detection or removal of other chemicals.

Disruption of normal adipocyte development and function by methyl- and propyl- paraben exposure.

Methyl- and propyl- parabens are generally regarded as safe by the U.S Food and Drug Administration and as such are commonly used in personal care products. These parabens have been associated with increased white adipogenesis in vitro and methyl paraben also increased the white adipose mass of mice. Given brown adipose also plays a role in energy balance, we sought to evaluate whether the effects of methyl- and propyl- parabens on white adipocytes extended to brown adipocytes. We challenged white and brown pre-adipocytes at low doses of both parabens (up to 1 µM) during the differentiation process and examined adipogenesis with the ORO assay. The impact of each paraben on glucose uptake and lipolytic activity of adipocytes were measured with a fluorescent glucose analog and enzymatically, respectively. Methyl- and propyl- parabens increased adipogenesis of 3T3-L1 white adipocytes but not brown adipocytes. In white adipocytes, methyl paraben increased glucose uptake and both parabens reduced basal lipolysis. However, in brown adipocytes, parabens had no effect on basal lipolysis and instead attenuated isoproterenol induced lipolysis. These data indicate that methyl- and propyl- parabens target the differentiation and metabolic processes of multiple types of adipocytes in a cell autonomous manner.

Micro solid phase extraction of parabens from breast milk samples using Mg-Al layered double hydroxide functionalized partially reduced graphene oxide nanocomposite.

In this study, a magnesium-aluminum layered double hydroxide coated on graphene oxide nanosheets was synthesized. It was successfully applied as an effective medium for determination of the parabens in human breast milk samples using micro solid phase extraction by packed sorbent (in spinal syringe format) followed by HPLC-UV. Effective parameters were optimized by central composite design. Under the optimal conditions, figures of merit of the developed method were obtained in which the limits of detection were found between 3.0 and 5.0 µg L-1. The calibration plots were linear in the range of 10-1000 µg L-1. Intra- and inter-day RSD% (n = 3) at two concentration levels of 25 and 250 µg L-1 varied between 4.2 and 9.5%. The relative recovery values for the spiked breast milk samples were in the acceptable range of 87.2-104.4%. Accordingly, the proposed method exhibits proper sensitivity, good repeatability, and acceptable applicability for the determination of parabens in complex matrices.