P-hydroxybenzoic Acid Esters Research Articles

Accumulation of Parabens, Their Metabolites, and Halogenated Byproducts in Migratory Birds of Prey: A Comparative Study in Texas and North Carolina, USA.

Parabens are alkyl esters of p-hydroxybenzoic acid that are commonly used as preservatives in personal care products such as cosmetics. Recent studies have revealed the presence of parabens in surface and tap water because of their use as disinfection products; however, little is known about their occurrence in biological samples and their bioaccumulation potential, particularly in raptor birds known as sentinels for pollutant detection. We examined the occurrence and tissue distribution of parabens, their metabolites, and halogenated byproducts in the liver, kidney, brain, and muscle of birds of prey from Texas and North Carolina (USA). Methylparaben (MeP), propylparaben (PrP), and butylparaben (BuP) were detected in more than 50% of all tissues examined, with the kidney exhibiting the highest concentration of MeP (0.65-6.84 ng/g wet wt). Para-hydroxybenzoic acid (PHBA), a primary metabolite, had the highest detection frequency (>50%) and a high accumulation range in the liver, of 4.64 to 12.55 ng/g. The chlorinated compounds chloromethylparaben and chloroethylparaben were found in over half of the tissues, of which dichloromethylparaben (2.20-3.99 ng/g) and dichloroethylparaben (1.01-5.95 ng/g) in the kidney exhibited the highest concentrations. The dibrominated derivatives dibromideethylparaben (Br2EtP) was detected in more than 50% of samples, particularly in muscle and brain. Concentrations in the range of 0.14 to 17.38 ng/g of Br2EtP were detected in the kidney. Dibromidepropylparaben (Br2PrP) was not frequently detected, but concentrations ranged from 0.09 to 21.70 ng/g in muscle. The accumulations of total amounts (sum) of parent parabens (∑P), metabolites (∑M), and halogenated byproducts (∑H) in different species were not significantly different, but their distribution in tissues differed among the species. Positive correlations were observed among MeP, PrP, BuP, and PHBA in the liver, suggesting similar origins and metabolic pathways. Environ Toxicol Chem 2024;43:2365-2376. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Parabens promotes invasive properties of multiple human cells: A potential cancer-associated adverse outcome pathway

Parabens are esters of p-hydroxybenzoic acid, which have been used as preservatives and considered safe for nearly a century, until the last two decades when concerns began to be raised about their association with cancers. Knowledge of the mode of action of parabens on the metastatic properties of different cancer cells is still very limited. In the present study, we investigated the effects of methylparaben (MP) and propylparaben (PP) on cell invasion and/or migration in multiple human cancerous and noncancerous cells, including hepatocellular carcinoma cells (HepG2), cervical carcinoma cells (HeLa), breast carcinoma cells (MCF-7), and human placental trophoblasts (HTR-8/SVneo). MP and PP at concentrations in a range of 5–500 μg/L significantly promoted the invasion of four cell lines, with a minimum effective concentration of 5 μg/L. MP and PP up-regulated the expression levels and enzymatic activities of matrix metalloproteinase 2 and 9 (MMP2 and MMP9), as well as altered the expression of the tissue inhibitors of metalloproteinase 1 and 2 (TIMP1 and TIMP2) in four cell lines, suggesting MMPs/TIMPs as potential key events (KEs) for paraben-induced cell invasion. Activation of the p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal protein kinases 1/2 (JNK1/2) signaling pathways was required for MP- and PP-promoted invasion of four cell lines, suggesting MAPK signaling pathways as candidates for KEs in cancer or noncancerous cells response to paraben exposure. This study showed for the first time that the two widely used parabens, MP and PP, promoted invasive capacity of multiple human cells through a common mode of action. This study provides evidence for the establishment of a potential cancer-associated AOP for parabens based on pathway-specific mechanism(s), which contributes towards assessing the health risks of these environmental chemicals.

Understanding parabens – A literature review

Parabens are esters of p-hydroxybenzoic acid that are widely used in cosmetic, pharmaceutical, and industrial products, among other excipients, for their preservative and antimicrobial properties. However, since the late 1900s, parabens’ use and safety have been surrounded by controversies relating to the potential causes of endocrine disruption, infertility, allergic skin reactions, and various cancers. Despite parabens being under a cloud of suspicion, these compounds have succeeded in extensive skin testing conducted by a variety of organizations in the United States. By dispelling misconceptions about the Paraben Paradox Theory, our review is aimed at determining the safety of topically applied parabens in cosmetics, the availability of alternatives, and their side effects.

Quantification of parabens in marine fish samples by a rapid, simple, effective sample preparation method.

Parabens (p-hydroxybenzoic acid esters) commonly used preservatives (in cosmetics, pharmaceuticals, and foods) can pose potential effects on environmental health. In this study, seven parabens were quantified in marine fish samples using an ultra-high performance liquid chromatography triple quadrupole mass spectrometer (UHPLC-MS/MS) system. Parabens in the fish samples were extracted and purified by a rapid, simple, and effective procedure comprising sample homogenization with solvent, solid-phase extraction clean-up, and solvent evaporation. Results demonstrated that the recoveries of seven compounds (with relative standard deviation < 15%) were 88-103% in matrix-spike samples and 86-105% in surrogate standards. The method detection limits and method quantification limits of seven parabens were 0.015-0.030 and 0.045-0.090ng/g-ww (wet weight), respectively. The optimized method was applied to measure the concentration of parabens in the 37 marine fish samples collected from Vietnam coastal waters. The concentration ranges of seven parabens found in round scad and greater lizardfish samples were 6.82-25.3ng/g ww and 6.21-17.2ng/g-ww, respectively. Among parabens, methylparaben accounted for the highest contribution in both fish species (43.2 and 44.9%, respectively). Based on the measured concentrations of parabens in marine fish samples, the estimated daily intake was calculated for children and adults with the corresponding values of 0.0477µg/kg/day and 0.0119µg/kg/day, respectively. However, the presence of parabens in Vietnamese marine fish may not pose a significant risk to human health.

An integrated transcriptome-microbiome host relationship associated with paraben toxicity in the brackish water flea Diaphanosoma celebensis

Parabens, a group of alkyl esters of p-hydroxybenzoic acid, have been found in aquatic systems in particular, leading to concerns about their potential impact on ecosystems. This study investigated the effects of three commonly used parabens, methylparaben (MeP), ethylparaben (EtP), and propylparaben (PrP), on the brackish water flea Diaphanosoma celebensis. The results showed that PrP had the most adverse impact on survival rates, followed by EtP and MeP, while MeP and EtP induced significant adverse effects on reproductive performance. A transcriptome analysis revealed significant differential gene expression patterns in response to paraben exposure, with MeP associated with the most significant effects. MeP and EtP exposure produced greater disruption in the microbiota of D. celebensis than did PrP compared with control groups, and we identified eight key microbiota, including Ruegeria and Roseovarius. Correlation analysis between transcriptome and microbiome data revealed key interactions between specific microbiota and host gene expression. Certain microbial taxa were associated with specific genes (e.g. cuticle related genes) and toxicological pathways, shedding light on the complex molecular response and in vivo toxicity effects of parabens. These findings contribute to a deeper understanding of the molecular mechanisms underlying paraben toxicity and highlight the importance of considering the ecological impact of chemical contaminants in aquatic ecosystems.

The occurrence and probabilistic risk of exposure to parabens from bottled and hand-shaken teas in the general adult population of Taiwan.

Parabens (PBs) are esters of p-hydroxybenzoic acid, and there are growing concerns due to their potential to disrupt endocrine function and their wide use as preservatives in foodstuffs, including beverages. The consumption of bottled and hand-shaken teas is gradually replacing traditional tea consumption through brewing. However, no study has reported PB concentrations in different types of teas or packaging and their associatedhealth risks. Our aimwasto determine the concentration of PBs (methyl- (MetPB), ethyl- (EthPB), propyl- (PropPB), butyl-paraben (ButPB)) in green, black, and oolong teas in two varieties of products (bottled and hand-shaken teas), using UPLC-MS/MS. Additionally,we estimated thehealth risks associated with tea consumption in the general adult population of Taiwan. A Monte Carlo simulation was applied to estimate the distribution of daily PB intake through bottled (n = 79) and hand-shaken (n = 71) tea consumption. Our findings revealed geometric mean concentrations in bottled green/black/oolong teas were 714.1/631.2/532.1ng/L for MetPB, 95.2/ 30.5/14.9 ng/L for EthPB, 77.9/28.3/non-detected (ND) ng/L for PropPB, and 69.3/26.6/ND ng/L for ButPB. Hand-shaken green/black/oolong teas exhibited concentrations of 867.5/2258/1307ng/L for MetPB, 28.5/28.8/14.5 ng/L for EthPB, 25.4/18.3/17.8 ng/L for PropPB, and 30.3/18.0/15.5 ng/L for ButPB. The median MetPB concentrations in hand-shaken black (2333ng/L) and oolong teas (1215ng/L) were significantly higher than those in bottled black (595.4ng/L) and oolong teas (489.3ng/L). Conversely, median concentrations of EthPB, PropPB, and ButPB in bottled teas were significantly higher than those in hand-shaken teas. MetPB was the predominant PB, constituting 73.2-91.9% in bottled teas and 85-94% in hand-shaken teas. Our results showed no health risks associated with bottled or hand-shaken tea consumption based on reference doses. However, the study highlights the importance of continued vigilance given the potential chronic exposure to PBs from various sources, necessitating ongoing concern despite the absence of immediate risks from tea consumption.

Ultrasound- and Vortex-Assisted Dispersive Liquid-Liquid Microextraction of Parabens from Personal Care Products and Urine, Followed by High-Performance Liquid Chromatography.

Parabens, which are p-hydroxybenzoic acid esters, are used as preservatives in personal care products, pharmaceuticals, and food because of their antimicrobial activity. However, they are also classified as suspected endocrine disruptors and carcinogens. In the present study, we aimed to optimize an ultrasound and vortex-assisted dispersive liquid-liquid microextraction (DLLME) procedure for the simultaneous extraction of methyl, ethyl, isopropyl, propyl, isobutyl, and butyl parabens from personal care products and urine. The extraction solvent type, extraction solvent volume, disperser solvent volume, sodium chloride concentration, ultrasonication time, and vortex application time were evaluated to obtain optimum recoveries by ultrasound and vortex-assisted DLLME. Parabens were detected using a validated high performanc-liquid chromatography (HPLC) method with fluorescence detection. Method validation was performed by examining linearity, the limit of detection, limit of quantification, accuracy, and precision. The limits of detection and quantification of the HPLC method were between 0.09-0.18 μg/mL and 0.28-0.54 μg/mL, respectively. Precision was examined as the relative standard deviation, which was 0.22-1.81% and 1.12-2.03% for intra- and interday studies. Recovery percentages were higher than 96.00%. Samples of two paraben-free personal care products and synthetic urine were spiked with the analyses at 0.02 μg/mL and were successfully analyzed using the developed procedure with recovery values higher than 82.00%. The proposed procedure provided quantification of selected parabens at 20 ng/mL in analyzed personal care products and urine matrices with good precision and accuracy.

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.

THE CHEMICAL COMPOSITION OF PARABEN AND ITS EFFECTS ON HEALTH

Parabens are a group of alkyl esters of p-hydroxybenzoic acid and usually include methyl paraben, ethyl paraben, propyl paraben, butyl paraben, isobutyl paraben, isopropyl paraben and benzyl paraben. Parabens (or their salts) are widely used as preservatives in cosmetics and medicine due to their relatively low toxicity and long history of safe use. Testing of parabens has shown, to varying degrees, that individual paraben compounds have weak estrogenic activity in some in vitro screening tests, such as estrogen receptor ligand binding, regulation of CAT gene expression, and proliferation of MCF-7 cells. Reported in vivo effects include uterine weight gain (eg, butyl, isobutyl, and benzyl parabens) and male reproductive tract effects (eg, butyl and propyl parabens). However, in relation to estrogen as a control during in vivo studies, parabens are much less active than estrogen. While exposure to sufficient doses of exogenous estrogens can increase the risk of certain adverse effects, it is hypothesized that similar risks may arise from exposure to much weaker endocrine-active chemicals (EACs) is still speculation. In evaluating the possibility that exposure to weakly active EACs may be associated with adverse effects due to their endocrine mode of action, it is important to consider both the dose and potency of these compounds compared to estrogen. In this review, a comparative approach involving dose and potency is used to assess whether in utero or adult exposure to parabens may be associated with adverse effects due to their estrogen-modulating mode of action. Keywords: parabens, p-Hydroxybenzoates, PHBA, paraben applications, Methyl paraben.

Presence of methyl paraben in anti-diabetic herbal preparations

Plant-based hypoglycemic therapeutics have been increasing in consumption due to the escalation of type 2 diabetes and its related complications. However, the safety of the preparations is little understood. Parabens (alkyl esters of p-hydroxybenzoic acid) are widely used as preservatives in these pharmaceuticals. However, the presence of methylparaben in formulations raises anxiety due to its potential endocrine disruption functions. Endocrine disruption could lead to undesirable health abnormalities and carcinogenic, estrogenic, and adverse reproductive effects. The present investigation directs toward estimating of methylparaben in some anti-diabetic herbal preparations using UV- Vis spectrophotometric method abiding by International Conference on Harmonization (ICH) guidelines for validation. The analytical wavelength of methylparaben in methanol was determined and found at 256.5 nm. The method obeys Beer’s law in the analytical range and has a good coefficient of determination (r2= 0.9881). The limit of detection (LOD) and limit of quantification (LOQ) were 0.19 ppm and 0.57 ppm, respectively. Recoveries were 91.3-98.8% in analyte-free plant matrix and 91-105.8 % in a diluent. The coefficient of variation (CV%) varied between 0.005- 0.268% for different standards. Results of forty-eight anti-diabetic herbal preparations showed methylparaben was detected in thirty-four samples in the range of 13.12 – 325.13 mg/day with a mean exposure value of 78.25 mg/day. However, none of the samples raise concerns about safety (the safety ceiling for paraben is 420 mg/day). More investigation is required to determine, whether the herbal drugs are safe to consume in terms of methylparaben. J. Asiat. Soc. Bangladesh, Sci. 48(1-2): 41-52, June-December 2022

The administration of methyl and butyl parabens interferes with the enzymatic antioxidant system and induces genotoxicity in rat testis: possible relation to male infertility

Parabens are esters of p-hydroxybenzoic acid, used for decades as a preservative in many products, including agrochemicals, pharmaceuticals, foods and cosmetics. Concerns regarding parabens toxicity include adverse effects on endocrine activity, carcinogenesis, infertility, spermatogenesis, and adipogenesis. The present study aimed to investigate the in vivo administration of methyl and butylparaben at concentrations of 100 and 200 mg/kg body weight, by subcutaneous injection, in variable murinometric measurements, antioxidant systems and genotoxicity. The administration of parabens did not affect the consumption of water and food. However, there was a decrease in the weight of the testes and the seminal vesicle (p < 0.05). The administration of parabens caused an increase in superoxide dismutase for methylparaben (200 mg/kg) and both concentrations of butylparaben (p < 0.05). Catalase showed increased activity in all groups treated with parabens. In contrast, glutathione reductase and glutathione S-transferase suffered a decrease in the groups treated with both parabens. These results show that parabens, especially butyl, can affect the rat testis enzymatic antioxidant system, decreasing the cellular antioxidant capacity, which was confirmed by the decrease in the glutathione reducing power, expressed by the reduced glutathione/oxidized glutathione ratio. Therefore, an increase in lipid peroxidation was observed, which was significant in the case of butyl. Genetic Damage Indicator values show that butylparaben treatments displayed significantly higher values than the control. This study shows for the first time that parabens can induce genotoxicity in the rat male reproductive organ.

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

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

Gamma radiolytic decomposition of methylparaben for environmental protection purposes

The methyl ester of p-hydroxybenzoic acid (methylparaben, MP) is commonly used as a preservative in cosmetics, food and pharmaceuticals. Its widely examined interactions with aqueous system and human organisms prove a necessity of the monitoring of its release to natural environment and the efficiency of its removal from waters and wastewaters.In this work, the yield of MP decomposition in aqueous solutions by gamma-radiation was investigated under oxidative conditions. The LC/MS, GC/MS and ion-chromatography were employed for examination of the yield of MP decomposition in function of the absorbed dose of radiation and for identification of stable products derived from MP formed during radiolysis prior to its complete mineralization. The studies were carried out in aerated aqueous solutions and under conditions with the predominance of OH radicals. The mechanisms of radical reactions were proposed leading to formation of the identified stable products. The irradiation of aerated MP solutions was assumed as a more favorable condition in terms of the yield of MP decomposition and a lack of changes of cytotoxicity towards 3 human cell lines was found. Under such conditions a 90% decomposition of MP at initial concentration 0.5 mg L−1 was observed for 100 Gy absorbed dose, which for the employed 60Co γ -source took 3.3 min. This provides a much better efficiency of MP decomposition in comparison to most of developed AOPs for this purpose.

Urinary parabens and breast cancer risk: Modification by LINE-1 and LUMA global DNA methylation, and associations with breast cancer defined by tumor promoter methylation status.

Parabens are a group of alkyl esters of p-hydroxybenzoic acid added to consumer products to prevent the growth of harmful bacteria and molds. Parabens are hypothesized to increase the risk of breast cancer (BC); however, no study has examined the interactions between parabens, global DNA methylation (DNAm), and BCrisk. We examined the modifying effects of DNAm on the associations between parabens and BC, and whether parabens were associated with BCdefined by tumor promoter methylation status. Participants included 708 cases and 598 controls from the Long Island Breast CancerStudy Project. Methylparaben (MPB), propylparaben, and butylparabenlevels were measured in spot urine samples. Global DNAm was measured by analysis of long interspersed elementes-1(LINE-1) and the luminometric methylation assay (LUMA). The promoter methylation status of 13 genes was measured in tumor samples from 509 cases. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between parabens and BC stratified by LINE-1/LUMA, and between parabens and gene-specific promoter methylation-defined BC. Outcome heterogeneity was evaluated using ratios of ORs (RORs). We assessed the joint effects of the multiple parabens using quantile g-computation. The highest versus lowest tertile of MPB and a one-quantile increase in all parabens were associated with ORs of 1.46 (95%CI = 0.96-2.23) and 1.32 (95%CI = 1.02-1.71), respectively, among women with hypomethylated LINE-1. A one-ln unit increase in MPB was associated with a 25% increase in the odds of hypomethylated (vs. hypermethylated) CCND2 promoter-defined BC (ROR = 1.25, 95%CI = 1.06-1.48), and a one-quantile increase in all parabens was associated with a 55% increase in the odds of hypomethylated (vs. hypermethylated) CCND2 promoter-defined BC (ROR = 1.55, 95%CI = 1.04-2.32). Exposure to parabens may increase the risk of BC among women with hypomethylated global DNAm and may increase the risk of tumors with gene-specific hypomethylated promoter regions.

The effect of chemical substances on endocrine disorder and related with morbidity and mortality of sperms in albino rats

Parabens are a group of alkyl esters of p-hydroxybenzoic acid that is commonly added to personal care products, cosmetics, pharmaceuticals, beverages, and food processing as an antimicrobial preservative. Butylparaben has been reported to cause sperm poisoning. To identify a previous marker of the toxicity of environmental substances or food additives, this study determined whether Butylparaben had an effect on the external appearance of sperm. Where several concentrations of 400mg/kg, 300mg/kg, and 200mg/kg were used daily for 20 days and dissolved in corn oil. It was found that it had an effect, as treatment with this substance led to a reduction in the weight of the testes and epididymis in the adult male rats used understudy. The results also showed a decrease in the number of sperms and their vitality compared to the control group, and the higher concentration used in the study had the greatest effect as compared to the other study groups and control, where the abnormalities in the sperm were represented by the twisting and breaking off the tail with the separation of the head in some sperms and the deformation of the head and the tail agglutination.

DFT investigation of SiO2 nanotube for adsorption of methyl- and propyl-paraben

A huge number of parabens, esters of p-hydroxybenzoic acid, are used in cosmetic and personal care products as preservative substances. Due to their detrimental effects on ecosystem and human health, taking precautionary measures to remove these compounds is an important task regarding the environmental issues. In this study, a silica (SiO2) nanotube has been selected as a novel sensor to adsorb the most common parabens which are methyl paraben and propyl paraben molecules. To this aim, density functional theory (DFT) calculations were used to evaluate the properties for investigated compounds. The calculated adsorption energies of the most stable configurations for methyl parban@SiO2 and propyl paraben@SiO2 complexes were found to be –0.238 and –0.242 eV, respectively. The electronic properties of nanotubes experienced dramatic changes in case of interactions with parabens, which led to declining the HOMO/LUMO energy gap of the nanotube to its original value. Such adsorption could also enhance the electrical conductivity of the nanotubes meaning that the utilized SiO2 nanotube could detect the existence of methyl and propyl parabens molecules in the environment. As a concluding remark, the investigated SiO2 nanotube could work as a possible sensor for hazardous paraben with the importance of environmental issues.

Dietary exposure to parabens and body mass index in an adolescent Spanish population

Parabens are alkyl esters of p-hydroxybenzoic acid which are extensively used in cosmetics, pharmaceuticals and foodstuffs due to their antimicrobial properties. The most commonly used parabens are methyl-(MeP), ethyl-(EtP), propyl-(PrP) and butyl-(BuP) paraben. Most human exposure to parabens is achieved through the consumption of food or pharmaceutical products and the use of personal care products. However, studies on dietary parabens exposure and the associated factors are very scarce. The main aim of the present study was to explore factors associated with dietary exposure to parabens in Spanish adolescents according to gender. Dietary data and anthropometric measures were collected from 585 adolescents (53.4% boys) aged 12–16 years. Parabens exposure through diet was assessed using a food frequency questionnaire with food products providing more than 95% of energy and macronutrient intake being included in analysis. Stepwise regression was used to identify the foods that most contributed to parabens intake. Logistic regression was used to evaluate factors predicting higher dietary exposure to parabens. The main contributors to dietary MeP, EtP, PrP and BuP exposure in adolescent boys were eggs (41.9%), canned tuna (46.4%), bakery and baked goods products (57.3%) and pineapple (61.1%). In adolescent girls, the main contributors were apples and pears (35.3%), canned tuna (42.1%), bakery and baked goods products (55.1%) and olives (62.1%). Overweight/obese girls were more likely to belong to the highest tertile of overall parabens intake (odds ratio [OR]: 3.32; 95% confidence interval [95% CI]: 1.21–9.15) and MeP (OR: 3.05; 95% CI: 1.14–8.12) than those with a body mass index lower than 25 kg/m2. These findings suggest a positive association between dietary exposure to parabens and overweight/obesity in adolescent girls.

Development and validation of a new method for determination of methylparaben in Iran market infant formulae by HPLC.

Parabens are esters of p-hydroxybenzoic acid and are widely used as preservatives in cosmetics, pharmaceuticals and foodstuffs. The presences of parabens in infant formulas raise concerns due to their potential to disrupt endocrine function in infants and cause reproductive toxicities. In this study a new method was developed for extraction and determination of methylparaben in infant formulas using HPLC method and UV detector. Methanol and trichloroacetic acid were used for extraction and isocratic mobile phase comprising equal proportions of glacial acetic acid in water (50:850 v/v) and methanol was used for separation of methylparaben. Recovery of the extraction procedure was good and interferences between methylparaben and other ingredients peaks in HPLC chromatograms decreased. The average recoveries for methylparaben were about 88-108 %. The limit of detection and limit of quantitation for methylparaben were 0.2 and 0.5µg/mL, respectively. Results of the method showed good reproducibility (relative standard deviation (RSD) 0.29-1.94 % for within day analysis and 0.84-2.18 % for between day analysis). Results were linear in range of 0.5-20µg/mL methylparaben. The results of twenty real infant formula samples showed methylparaben was found only in one sample in concentration 0.3µg/mL. The new extraction and measurement method was a short-time method and could be applicable for large numbers of samples. This method was fast, sensitive and accurate and was capable of being used in legal laboratory references for determination of methylparaben content.

Separation of methylparaben from aqueous source stream by pseudo-emulsion hollow fiber membrane strip dispersion technique: Optimization of process parameters using Grey-Taguchi method

Parabens are the esters of p-hydroxybenzoic acid extensively used as antimicrobial preservatives in food, pharmaceuticals and personal care products. These compounds have been reported to have estrogenic and antiandrogenic properties. The separation of methylparaben from water by hollow fiber supported liquid membrane (HFSLM) and pseudo-emulsion hollow fiber membrane strip dispersion (PEHFSD) technique was studied. Output responses: permeability and stripping percentage were maximized by Grey-Taguchi technique. Concentrations of methylparaben in the three phases at equilibrium were in good agreement with the values calculated from the material balance. Stripping percentage for HFSLM and PEHFSD system were 67% and 90.52% respectively at a contact time of 90 minutes. The estimated permeability was 3.8859 × 10−5 and 7.8041 × 10−5 cm/sec for HFSLM and PEHFSD system respectively.

Pollution characteristics, temporal records, and risks associated with parabens and mercury in sediments from the upper Huai River, Henan Province

Mercury (Hg), six alkyl esters of p-hydroxybenzoic acid (parabens), and their metabolite, 4-hydroxybenzoic acid (PHBA), were simultaneously studied in sediments from the upper Huai River, Henan Province, China. There were higher concentrations of Hg in the surface sediments from the Huai River during the moderate precipitation season (MPS②) as compared to the minimal precipitation (MPS①) and high precipitation seasons (HPS), and as compared to core sediments. The Hg values in all sediments were above the background value. The Hg contents in the tributaries were much higher than those in the mainstream. The concentrations of ∑parabens in the core sediments ranged from 2.45 to 22.2 ng/g while the concentrations of PHBA ranged from 11.3 to 155 ng/g. Methylparaben (MeP) and propylparaben (PrP) were the most commonly detected parabens. Total organic carbon (TOC) and black carbon (BC) played important roles in the distribution of Hg in the surface sediments during the minimal precipitation and high precipitation seasons and affect the distribution of Hg and parabens in core sediments. Sand (>63 μm) was another factor affecting the distribution of Hg and parabens in core sediments. The concentrations of PHBA and Hg in core sediments were positively correlated. Temporal records of Hg and parabens in core sediments reflected local social changes. Hg content in the surface sediments during the MPS② was associated with relatively high ecological risks while parabens in the core sediments were associated with low level risks.