SciCombinator

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Concept: Phthalate

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Prenatal and early postnatal exposures to environmental factors are considered responsible for the increasing prevalence of allergic diseases. Although there is some evidence for allergy-promoting effects in children due to exposure to plasticizers like phthalates, findings of previous studies are inconsistent and lack mechanistic information.

Concepts: Phthalates, Phthalate, Plasticizer

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Phthalates are ubiquitous chemicals linked to hormonal disruptions that affect reproduction and development. Multiple anti-androgenic phthalates exposure during fetal development can have greater impacts than individual exposure; thus, the National Academy of Sciences (NAS) recommends them for cumulative assessment. Using National Health and Nutrition Examination Survey data (NHANES, 2001-2012), we developed a potency-weighted sum of daily intake (∑androgen-disruptor; µg/kg/day) of di-n-butyl phthalate (DnBP), diisobutyl phthalate (DiBP), butyl benzyl phthalate (BBzP), and di(2-ethylhexyl) phthalate (DEHP) based on NAS recommendations, and included diethyl phthalate (DEP) and diisononyl phthalate (DiNP) in additional metrics (2005-2012). We compared racial/ethnic differences in ∑androgen-disruptor among 2842 reproductive-aged women. In sensitivity analyses, we assessed the influence of potency assumptions, alternate urine dilution adjustment methods, and weighting phthalate metabolites directly rather than daily intake estimates of parent compounds. We found that DEHP contributed most to ∑androgen-disruptor (48-64%), and that ∑androgen-disruptor decreased over time. Black women generally had higher cumulative exposures than white women, although the magnitude and precision of the difference varied by model specification. Our approach provides a blueprint for combining chemical exposures linked to common adverse outcomes, and should be considered in future exposure, risk, and epidemiological studies.

Concepts: Phthalates, Phthalate, Diethyl phthalate, Plasticizer, Bis(2-ethylhexyl) phthalate, Plasticizers, Diisononyl phthalate, Diisoheptyl phthalate

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Di-(2-ethylhexyl) phthalate (DEHP) is a plasticizer widely used in the production of poly-(vinyl) chloride (PVC) materials. It is a reproductive and developmental toxicant in animals and a suspected endocrine modulator in humans. DEHP is not covalently bound within the PVC molecule, which is why migration into a suitable medium can be expected. Since application of infusion solutions is one of the most common medical treatments, the objective of this study was to determine the migration of phthalates from softened PVC storage bags into infusion solution in different time periods within one year from date of production using a gas chromatography-mass spectrometry method. The measured values of DEHP ranged between 0.22 and 14.00 µg l(-1) , but the unexpected presence of other phthalate esters was also detected. It was concluded that values obtained in infusion solutions match the reference data and represent a minor risk for the patient. The presence of other phthalate esters leads to the conclusion that the pharmacopeic requirement for polymer cleanness was not fully met. Since phthalate esters are among the most extensively used industrial chemicals and are widely distributed in the environment, special precautions and further monitoring should be conducted to minimize any possible health risks.

Concepts: Chemistry, Plastic, Phthalates, Phthalate, Plasticizer, Bis(2-ethylhexyl) phthalate, Plasticizers, Diisononyl phthalate

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This survey determined the levels of eight phthalates - i.e. dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), benzylbutyl phthalate (BzBP), di(2-ethylhexyl) phthalate (DEHP), dicyclohexyl phthalate (DCHP) and di-n-octyl phthalate (DnOP) - in several Belgian milk and dairy products. Samples were obtained from various farms, a dairy factory and from different shops in order to investigate phthalate contamination “from farm to fork”. At several stages in the milk chain, product contamination with phthalates - mostly DiBP, DnBP, BzBP and DEHP - was observed. At farm level, the mechanical milking process and the intake of phthalate containing feed by the cattle were found to be possible contamination sources. At industry and retail level, contact materials including packaging materials were additional contamination sources for phthalates in milk and dairy products.

Concepts: Milk, Cattle, Dairy, Phthalates, Phthalate, Diethyl phthalate, Plasticizers, Diisobutyl phthalate

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Human exposure to phthalates was assessed through digestive and respiratory intakes. Six phthalates (DMP, DEP, DnBP, BBP, DEHP, DnOP) were investigated in drinking water, in current foodstuff and in ambient air. Digestive intake was prevailing (92 %) with a major contribution of food (95.5 %). Phthalate intake from water was mainly due to bottled water (60 %) in spite of the minor volume absorbed daily. From the respiratory tract, it was dominated by DEP: 30.3 ng kg(-1) bw day(-1) and the part played by indoor air prevailed. Total intake were as ng kg(-1) bw day(-1), for DEHP: 1458, DnBP: 191.8, BBP: 164.3, DEP: 107.7, DMP: 79.1.

Concepts: Water, Assessment, Phthalates, Phthalate, Bottled water, Plasticizer, Intake, Bis(2-ethylhexyl) phthalate

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Esters of phthalic acid are chemical agents used to improve the plasticity of industrial polymers. Their ubiquitous use in multiple commercial products results in extensive exposure to humans and the environment. This study investigated cytotoxicity, endocrine disruption, effects mediated via AhR, lipid peroxidation and effects on expression of enzymes of xenobiotic metabolism caused by di-(2-ethy hexyl) phthalate (DEHP), diethyl phthalate (DEP), dibutyl phthalate (DBP) and benzyl butyl phthalate (BBP) in developing fish embryos. Oxidative stress was identified as the critical mechanism of toxicity (CMTA) in the case of DEHP and DEP, while the efficient removal of DBP and BBP by phase 1 enzymes resulted in lesser toxicity. DEHP and DEP did not mimic estradiol (E(2)) in transactivation studies, but at concentrations of 10mg/L synthesis of sex steroid hormones was affected. Exposure to 10mg BBP/L resulted in weak transactivation of the estrogen receptor (ER). All phthalates exhibited weak potency as agonists of the aryl hydrocarbon receptor (AhR). The order of potency of the 4 phthalates studied was; DEHP>DEP>BBP>DBP. The study highlights the need for simultaneous assessment of (1) multiple cellular targets affected by phthalates and (2) phthalate mixtures to account for additive effects when multiple phthalates modulate the same pathway. Such cumulative assessment of multiple biological parameters is more realistic, and offers the possibility of more accurately identifying the CMTA.

Concepts: Metabolism, Estrogen, Steroid, Phthalates, Phthalate, Phthalic acid, Bis(2-ethylhexyl) phthalate, Dibutyl phthalate

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Food products can be contaminated with toxic compounds via the environment. Another possibility of food contamination is that toxicants are generated in foods or that chemicals migrate from food contact materials into foods during processing. In this study, the effect of cooking at home on the levels of phthalates - world’s most used group of plasticisers - in various food types (starchy products, vegetables and meat and fish) was examined. Eight compounds were considered, namely dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), benzylbutyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), dicyclohexyl phthalate (DCHP) and di-n-octyl phthalate (DnOP). Food products were analysed before as well as after cooking (boiling, steaming, (deep-)frying or grilling). In general, phthalate concentrations in foods declined after cooking, except in vegetables, where almost no effect was seen. Several factors influenced the degree of this decline (e.g. weight difference, fat uptake, etc.). Of all phthalates, DEHP, DiBP and BBP were affected the most. In conclusion, cooking at home definitely affected phthalate concentrations in foods and thus needs to be considered in order to correctly assess humans' dietary exposure to these contaminants.

Concepts: Nutrition, Food, Phthalates, Phthalate, Food safety, Cooking, Bis(2-ethylhexyl) phthalate, Plasticizers

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A comprehensive study of the sonochemical degradation of dimethyl phthalate (DMP) was carried out using high-frequency ultrasonic processes. The effects of various operating parameters were investigated, including ultrasonic frequency, power density, initial DMP concentration, solution pH and the presence of hydrogen peroxide. In general, a frequency of 400kHz was the optimum for achieving the highest DMP degradation rate. The degradation rate was directly proportional to the power density and inversely related to the initial DMP concentration. It was interesting to find that faster removal rate was observed under weakly acidic condition, while hydrolysis effect dominated in extreme-basic condition. The addition of hydrogen peroxide can increase the radical generation to some extent. Furthermore, both hydroxylation of the aromatic ring and oxidation of the aliphatic chain appear to be the major mechanism of DMP degradation by sonolysis based on LC/ESI-MS analysis. Among the principle reaction intermediates identified, tri- and tetra-hydroxylated derivatives of DMP, as well as hydroxylated monomethyl phthalates and hydroxylated phthalic acid were reported for the first time in this study. Reaction pathways for DMP sonolysis are proposed based on the detected intermediates.

Concepts: Oxygen, Acid, Redox, PH, Ultrasound, Phthalates, Phthalate, Phthalic acid

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We report that aryl phthalate esters are fast and robust self-immolative linkers. This linker is easy to conjugate and releases output phenols within seconds upon cleaving a fluoride-sensitive mask to yield a benign phthalic acid byproduct, making these linkers potentially useful as fluoride sensors and promising for use in biological and materials applications.

Concepts: Alcohol, Functional groups, Phthalate, Phthalic acid, Linkers, Linker, Phthalic anhydride

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Several phthalates, particularly diethyl phthalate (DEP) and di-n-butyl phthalate, can be used in personal care products (PCPs) to fix fragrance and hold color. We investigated associations between women’s reported use of PCPs within the 24 h before urine collection and concentrations of several urinary phthalate metabolites. Between 2002 and 2005, 337 women provided spot urine samples and answered questions regarding their use of 13 PCPs at a follow-up visit 3-36 months after pregnancy. We examined associations between urinary concentrations of several phthalate metabolites and use of PCPs using linear regression. Use of individual PCPs ranged from 7% (nail polish) to 91% (deodorant). After adjusting for age, education, and urinary creatinine, women reporting use of perfume had 2.92 times higher (95% CI: 2.20-3.89) concentration of monoethyl phthalate (MEP; the primary metabolite of DEP) than other women. Other PCPs that were significantly associated with MEP concentrations included: hair spray, nail polish, and deodorant. MEP concentrations increased with the number of PCPs used. PCP use was widespread in this group of recently pregnant women. Women’s use of PCPs, particularly of perfumes and fragranced products, was positively associated with urinary concentration of multiple phthalate metabolites.Journal of Exposure Science and Environmental Epidemiology advance online publication, 21 November 2012; doi:10.1038/jes.2012.105.

Concepts: Pregnancy, Phthalates, Cosmetics, Toiletry, Perfume, Phthalate, Metabolite, Diethyl phthalate