Showing papers on "Dibutyl phthalate published in 2014"

Prenatal Phthalate Exposures and Anogenital Distance in Swedish Boys

Abstract: BACKGROUND: Phthalates are used as plasticizers in soft polyvinyl chloride (PVC) and in a large number of consumer products. Because of reported health risks, diisononyl phthalate (DiNP) has been introduced as a replacement for di(2-ethylhexyl) phthalate (DEHP) in soft PVC. This raises concerns because animal data suggest that DiNP may have antiandrogenic properties similar to those of DEHP. The anogenital distance (AGD)-the distance from the anus to the genitals-has been used to assess reproductive toxicity. OBJECTIVE: The objective of this study was to examine the associations between prenatal phthalate exposure and AGD in Swedish infants. METHODS: AGD was measured in 196 boys at 21 months of age, and first-trimester urine was analyzed for 10 phthalate metabolites of DEP (diethyl phthalate), DBP (dibutyl phthalate), DEHP, BBzP (benzylbutyl phthalate), as well as DiNP and creatinine. Data on covariates were collected by questionnaires. RESULTS: The most significant associations were found between the shorter of two AGD measures (anoscrotal distance; AGDas) and DiNP metabolites and strongest for oh-MMeOP [mono(4-methyl-7-hydroxyloctyl) phthalate] and oxo-MMeOP [mono-(2-ethyl-5-oxohexyl) phthalate]. However, the AGDas reduction was small (4%) in relation to more than an interquartile range increase in DiNP exposure. CONCLUSIONS: These findings call into question the safety of substituting DiNP for DEHP in soft PVC, particularly because a shorter male AGD has been shown to relate to male genital birth defects in children and impaired reproductive function in adult males and the fact that human levels of DiNP are increasing globally.

Phthalate exposure and risk assessment in California child care facilities.

Abstract: Approximately 13 million U.S. children less than 6 years old spend some time in early childhood education (ECE) facilities where they may be exposed to potentially harmful chemicals during critical periods of development. We measured five phthalate esters in indoor dust (n = 39) and indoor and outdoor air (n = 40 and 14, respectively) at ECE facilities in Northern California. Dust and airborne concentrations were used to perform a probabilistic health risk assessment to compare estimated exposures with risk levels established for chemicals causing reproductive toxicity and cancer under California’s Proposition 65. Di(2-ethylhexyl) phthalate (DEHP) and butyl benzyl phthalate (BBzP) were the dominant phthalates present in floor dust (medians = 172.2 and 46.8 μg/g, respectively), and dibutyl phthalate (DBP), diethyl phthalate (DEP), and diisobutyl phthalate (DIBP) were the dominant phthalates in indoor air (medians = 0.52, 0.21, and 0.10 μg/m3, respectively). The risk assessment results indicate that 82–89% ...

Reproductive toxicity of lead, cadmium, and phthalate exposure in men.

Abstract: Environmental toxicants viz lead or cadmium and phthalate esters (di(2-ethylhexyl) phthalate [DEHP], dibutyl phthalate [DBP], and diethyl phthalate [DEP]) widely found in different environmental strata are linked to deteriorating male reproductive health. The objective was to assess the relationships between the seminal lead, cadmium, and phthalate (DEHP, DBP, DEP) concentrations at environmental level and serum hormone levels and semen quality in non-occupationally exposed men and specify the effect of individual and combined exposure of toxicants on semen quality. A study of 60 male partners of couples attending the Andrology Laboratory of the Reproductive Biology Department, All India Institute of Medical Sciences (AIIMS), New Delhi, India for semen analysis to assess their inability to achieve a pregnancy was selected for the study. The results of univariate and stepwise multiple regression analysis in the unadjusted model showed a significant correlation between lead or cadmium and phthalates DEHP/DBP/DEP and sperm motility, sperm concentration, and DNA damage. After adjusting for potential confounders, an association with lead or DEHP was only observed. The present data shows that lead (Pb) or cadmium (Cd) or phthalates might independently contribute to decline in semen quality and induce DNA damage. Phthalates might influence reproductive hormone testosterone. These findings are significant in light of the fact that men are exposed to a volley of chemicals; however, due to the small sample size, our finding needs to be confirmed in a larger population.

Lower concentrations of phthalates induce proliferation in human breast cancer cells

Abstract: Objective To explore the effect and pathway of phthalates on the growth of MCF-7 breast cancer cells.Methods MCF-7 cells were treated with benzyl butyl phthalate (BBP), di-n-butyl phthalate (DBP), and di-2-ethylhexyl phthalate (DEHP) (10−10–10−4 mol/l). After incubation for 24, 48, 72, and 92 h, the cells were harvested and extracted for 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The proteins involving proliferative and apoptotic pathways were evaluated by Western blot analysis.Results MTT assay revealed cell toxicity at more than 10−5 mol/l for DEHP and at 10−4 mol/l for both BBP and DBP in MCF-7 cells. Cell proliferation was significantly increased at 10−8–10−5 mol/l of BBP and DBP, and at 10−8–10−6 mol/l of DEHP treatment. Proliferating cell nuclear antigen (PCNA) was substantially increased in cultures with DEHP (10−8–10−6 mol/l), BBP (10−8–10−5 mol/l), and DBP (10−7–10−5 mol/l). Obvious increases in PI3K, p-AKT, and PCNA were noted in cultures with 17β-estradiol...

Properties of the plant- and manure-derived biochars and their sorption of dibutyl phthalate and

Abstract: The properties of plant residue-derived biochars (PLABs) and animal waste-derived biochars (ANIBs) obtained at low and high heating treatment temperatures (300 and 4506C) as well as their sorption of dibutyl phthalate (DBP) and phenanthrene (PHE) were investigated in this study. The higher C content of PLABs could explain that CO2-surface area (CO2-SA) of PLABs was remarkably high relative to ANIBs. OC and aromatic C were two key factors influencing the CO2-SA of the biochars. Much higher surface C content of the ANIBs than bulk C likely explained that the ANIBs exhibited higher sorption of DBP and PHE compared to the PLABs. H-bonding should govern the adsorption of DBP by most of the tested biochars and p-p interaction play an important role in the adsorption of PHE by biochars. High CO2-SA (.200 m 2 g 21 ) demonstrated that abundant nanopores of OC existed within the biochars obtained 4506C (HTBs), which likely result in high and nonlinear sorption of PHE by HTBs.

Occurrence of estrogenic endocrine disrupting chemicals concern in sewage plant effluent

Abstract: The purpose of this study was to give a worldwide overview of the concentrations of typical estrogenic endocrine disrupting chemicals (EDCs) in the effluent of sewage plants and then compare the concentration distribution of the estrogenic EDCs in ten countries based on the survey data of the estrogenic EDCs research. The concentrations of three main categories (totally eight kinds) of estrogenic EDCs including steroidal estrogens (estrone (E1), estradiol (E2), estriol (E3) and 17α-ethynylestradiol (EE2)), phenolic compounds (nonylphenol (NP) and bisphenol A (BPA)) and phthalate esters (dibutyl phthalate (DBP) and dibutyl phthalate (2-ethylhexyl) phthalate (DEHP)) in the effluents of sewage plants reported in major international journals over the past decade were collected. The statistics showed that the concentration distributions of eight kinds of EDCs were in the range of ng·L−1 to μg·L−1. The concentrations of steroidal estrogens mainly ranged within 50.00 ng·L−1, and the median concentrations of E1, E2, E3 and EE2 were 11.00, 3.68, 4.90 and 1.00 ng·L−1, respectively. Phenolic compounds and phthalate esters were found at μg·L−1 level (some individual values were at the high level of 40.00 μg·L−1). The median concentrations of BPA, NP, DBP and DEHP were 0.06, 0.55, 0.07 and 0.88 μg·L−1, respectively. The concentrations of phenolic compounds and phthalate esters in the effluents were higher than that of steroids estrogens. The analysis of the concentration in various ten countries showed that steroids estrogens, phenolic compounds and phthalate esters in sewage plant effluents were detected with high concentration in Canada, Spain and China, respectively.

Observing Phthalate Leaching from Plasticized Polymer Films at the Molecular Level

Abstract: Phthalates, the most widely used plasticizers in poly(vinyl chloride) (PVC), have been extensively studied. In this paper, a highly sensitive, easy, and effective method was developed to examine short-term phthalate leaching from PVC/phthalate films at the molecular level using sum frequency generation vibrational spectroscopy (SFG). Combining SFG and Fourier transform infrared spectroscopy (FTIR), surface and bulk molecular structures of PVC/phthalate films were also comprehensively evaluated during the phthalate leaching process under various environments. The leaching processes of two phthalates, diethyl phthalate (DEP) and dibutyl phthalate (DBP), from the PVC/phthalate films with various weight ratios were studied. Oxygen plasma was applied to treat the PVC/phthalate film surfaces to verify its efficacy on preventing/reducing phthalate leaching from PVC. Our results show that DBP is more stable than DEP in PVC/phthalate films. Even so, DBP molecules were still found to very slowly leach to the enviro...

Dibutyl phthalate-induced neurotoxicity in the brain of immature and mature rat offspring.

Abstract: Purpose : We aim to investigate the neurotoxicity induced by perinatal exposure of dibutyl phthalate (DBP) on the immature and mature offspring animals using a rodent model. Methods : Pregnant rats were given intragastric administration of 500mg/kg body weight DBP daily from gestational day 6 to postnatal day 21 while control animals received the same volume of edible corn oil. Serum estradiol and testosterone levels of the offspring were evaluated. Protein levels of AROM, ER-β, BDNF and p-CREB in the hippocampus were also measured. Results : Perinatal exposure of DBP significantly up-regulated the serum estradiol levels in both immature and mature offspring rats. DBP exposure also significantly down-regulated the testosterone levels in immature male and female rats and mature male rats but had no influence on the testosterone levels in mature female rats. DBP exposure up-regulated AROM, but down-regulated ER-β, BDNF and p-CREB expression in the hippocampus of immature rat offspring, while it had no influence on the levels of these proteins in the mature animals. Conclusions : Perinatal exposure of DBP could induce neurotoxicity in immature offspring rats through regulation of AROM, ER-β, BDNF and p-CREB expression, while it has no influence on mature offspring animals.

Toxicity of phthalate esters exposure to carp ( Cyprinus carpio ) and antioxidant response by biomarker

Abstract: To study the toxic effects of phthalate esters on the aquatic creatures, carps were exposed to dibutyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) of six different concentrations for 96 h-LC50 measurements. It shows that the 96 h-LC50 is 16.30 and 37.95 mg L−1, thus the safe concentration (1/10LC50) is 1.63 mg L−1. The activities of xanthine oxidase (XOD) and catalase (CAT) were measured in liver to carp exposure for single or combinations of DBP and DEHP. The quantity of malonic dialdehyde (MDA) was also measured in the same way. XOD, CAT and MDA had shown an evident change while exposure time and concentration increased, combined exposure can aggravate this change. They might be used as early warning indicators and monitors, and have potentials in the ecological risk assessment.

Contamination of wines and spirits by phthalates: types of contaminants present, contamination sources and means of prevention

Abstract: This research determines the concentrations of various phthalates in French wines and grape spirits marketed in Europe or intended for export. Dibutyl phthalate (DBP), diethylhexyl phthalate (DEHP) and butyl benzyl phthalate (BBP) were the most frequently detected compounds in the wines analysed. While only 15% of the samples examined contained quantifiable concentrations (> 0.010 mg kg–1) of DEHP and BBP, 59% of the wines contained significant quantities of DBP, with a median value as high as 0.0587 mg kg–1. Only 17% of the samples did not contain any detectable quantity of at least one of the phthalates and 19% contained only non-quantifiable traces. In the spirits analysed, DBP (median = 0.105 mg kg–1) and DEHP (median = 0.353 mg kg–1) were the substances measured at the highest concentrations, as well as the most frequently detected (90% of samples). BBP was present in 40% of the samples at an average concentration of 0.026 mg kg–1. Di-isobutyl phthalate (DiBP), which is not permitted in contact with ...

Fungal biodegradation of dibutyl phthalate and toxicity of its breakdown products on the basis of fungal and bacterial growth

Abstract: Phthalates are esters of phthalic acid that give flexibility to polyvinyl chloride. Diverse studies have reported that these compounds might be carcinogenic, mutagenic and/or teratogenic. Radial growth rate, biomass, hyphal thickness of Neurospora sitophyla, Trichoderma harzianum and Aspergillus niger, grown in two different concentrations of dibutyl phthalate (DBP) (500 and 1,000 mg/l) in agar and in submerged fermentation were studied. The inhibitory concentration (IC50) and the constant of biodegradation of dibutyl phthalate in Escherichia coli cultures were used to evaluate toxicity. The radial growth rate and thickness of the hypha were positively correlated with the concentration of phthalate. The pH of the cultures decreased as the fermentation proceeded. It is shown that these fungi are able to degrade DBP to non-toxic compounds and that these can be used as sole carbon and energy sources by this bacterium. It is demonstrated that the biodegradation of the DBP is directly correlated with the IC50. This is the first study that reports a method to determine the biodegradation of DBP on the basis of the IC50 and fungal growth, and the effect of this phthalate on the growth and thickness of hyphae of filamentous fungi in agar and in submerged fermentation.

T-Helper Type-2 Contact Hypersensitivity of Balb/c Mice Aggravated by Dibutyl Phthalate via Long-Term Dermal Exposure

Abstract: Objective During the last few decades, the prevalence of allergic skin diseases, asthma and rhinitis, has increased worldwide. Introduction of environmental chemicals with aggravation effects may play a part in this increase. The artificial chemical product dibutyl phthalate (DBP) is used in many products used in daily life. Dermal exposure to DBP is a common (but easily neglected) exposure pattern. Methodology/Principal Findings In this study, we examined the aggravation effect of long-term dermal exposure to DBP in a T-helper type 2 (Th2) model of contact hypersensitivity (CHS) in mice, and sought the potential molecular mechanisms. Experimental tests were conducted after 40-day dermal exposure to saline or three concentrations of DBP and subsequent three times of sensitization with 0.5% fluorescein isothiocyanate (FITC) or vehicle. The results of immunological and inflammatory biomarkers (total-immunoglobulin (Ig)E and Th cytokines) as well as histopathological examination and measurement of ear swelling supported the notion that high doses of DBP may promote and aggravate atopic dermatitis. Increased expression of thymic stromal lymphopoietin (TSLP) in this mouse model suggested that TSLP might be one of the molecular mechanisms of the aggravation effect induced by DBP. Conclusions/Significance Together, these results indicated that long-term dermal exposure to types of environmental toxins such as phthalates may endow an atopic predisposition in animals or humans. In addition, the high expression of TSLP in the mouse model demonstrated that TSLP might have an important role in the aggravation effect. This result could help to provide effective prevention strategies against atopic diseases such as atopic dermatitis (AD).

Effects of di-n-butyl phthalate on the physiology and ultrastructure of cucumber seedling roots.

Abstract: Agricultural pollution caused by the use of plastic sheetings has been documented to be a widespread problem in most of the major crop-planting regions of the world. In order to better understand the phytotoxic mechanisms induced by phthalic acid esters involved with this problem, Cucumber sativus L. cv Jinyan No. 4 were sown in pots to the three-leaf-stage in the presence of di-n-butyl phthalate (DBP; 0, 30, 50, 100, and 200 mg L−1) for 1, 3, 5, or 7 days. Physiology, biochemistry, and ultrastructure of seedling roots were examined. The results indicated that activities of three antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD)) were stimulated at low-DBP treatments and decreased under higher levels (>100 mg L−1) compared to the controls. On the other hand, SOD and POD provided a better defense against DBP-induced oxidative damage in the roots of cucumber seeding, compared to CAT. The productions of both malondialdehyde (MDA) and proline (Pro) were promoted under DBP stress. Visible impact on the cytoderm, mitochondrion, and vacuole was detected, possibly as a consequence of free radical generation. These results suggested that activation of the antioxidant system by DBP led to the formation of reactive oxygen species that resulted in cellular damage.

Distribution and sources of phthalate esters in the topsoils of Beijing, China

Abstract: Phthalate esters in the topsoil samples collected from Beijing were determined by derivatization and gas chromatography–mass spectrometry techniques. The results showed that diethyl phthalate (DEP), diisobutyl phthalate ester (DIBP), dibutyl phthalate ester (DBP), dibutyl (2-ethyl hexyl) phthalate (DEHP), and dimethyl phthalate (DMP) were found in the topsoils. The total concentrations of the five phthalate esters varied from 2.30 to 24.71 μg g−1. According to phthalate esters (PAEs) control standards in soil of the USA, the standard exceeding rates of DMP, DBP, and DEHP were 100 %, 100 %, and 4.84 % in soils of Beijing, respectively. The rate of DBP exceeding soil remediation standard was 12.9 %. Overall, concentrations of PAEs in Beijing were at a high level in China. The concentrations of DBP, DEHP, and DIBP were high, and the total concentrations of all the phthalate esters were higher in the areas with intensive human activities than in the other areas, which may be related to the use of phthalate compounds (such as the use of plastic products). The total and individual concentrations of phthalate compounds were relatively low in the areas that used plastic films compared with other samples due to the diffusion of atmospheric motion, categories, and amounts of plastic products and other factors. The greatest contributor may be the usage amount of plastic products in people’s daily lives.

Sorption behavior of dibutyl phthalate and dioctyl phthalate by aged refuse.

Abstract: Sorption is a fundamental process controlling the transformation, fate, degradation, and biological activity of hydrophobic organic contaminants in the environment. We investigated the kinetics, isotherms, and potential mechanisms for the sorption of two phthalic acid esters (PAEs), dibutyl phthalate (DBP) and dioctyl phthalate (DOP), on aged refuse. A two-compartment first-order model performed better than a one-compartment first-order model in describing the kinetic sorption of PAEs, with a fast sorption process dominating. Both the Freundlich and Dubinin–Astakhov (DA) models fit the sorption isotherms of DBP and DOP, with the DA model being of a better fit over the range of apparent equilibrium concentrations. The values of the fitting parameters (n, b, E) of the PAEs suggest nonlinear sorption characteristics. Higher predicted partition coefficient values and saturated sorption capacity existed in refuse containing larger quantities of organic matter. The sorption capacity of DOP was significantly higher than that of DBP. PAE sorption was dependent on liquid phase pH. Desorption hysteresis occurred in PAE desorption experiments, especially for the long-chain DOP. PAEs may therefore be a potential environmental risk in landfill.

Indirect Competitive Enzyme-Linked Immunosorbent Assay for the Detection of Dibutyl Phthalate in White Wine, Compared With GC-MS

Abstract: Plasticizer has attracted more and more attention in China for the past 3 years, especially in Taiwan district. In this study, an indirect competitive enzyme-linked immunosorbent assay (icELISA) has been developed for the determination of a plasticizer dibutyl phthalate (DBP) in white wine. Dibutyl 4-aminophthalate coupled with OVA was synthesized as an immunogen to produce polyclonal antibodies against DBP. The antibody exhibited negligible cross-reactivity with other related compounds. The influence of several physicochemical parameters, such as coating procedure, organic solvent, competitive reaction time, and pH was investigated. The limit of detection was 64.5 ng/mL, which was sensitive enough for a screening assay. The linear range was 64.5–1,606.2 ng/mL with a correlation coefficient (R 2) of 0.996. The method was successfully applied to the determination of DBP in white wine. Recoveries were between 83.1 and 101.7 %. This immunoassay was highly specific, sensitive, rapid, simple, and suitable for DBP monitoring. The results obtained were compared with those obtained using gas chromatography–mass spectrometry (GC-MS), and a satisfied correlation coefficient of 0.928 was obtained by real sample detection.

Effect of zirconium oxide nanofiller and dibutyl phthalate plasticizer on ionic conductivity and optical properties of solid polymer electrolyte.

Abstract: New solid polymer electrolytes (SPE) based on poly(ethylene oxide) (PEO) doped with lithium trifluoromethanesulfonate (LiCF3SO3), dibutyl phthalate (DBP) plasticizer, and zirconium oxide (ZrO2) nanoparticles were prepared by solution-casting technique. The conductivity was enhanced by addition of dibutyl phthalate (DBP) plasticizer and ZrO2 nanofiller with maximum conductivity (1.38 × 10(-4) Scm(-1)). The absorption edge and band gap values showed decreases upon addition of LiSO3CF3, DBP, and ZrO2 due to the formation of localized states in the SPE and the degree of disorder in the films increased.

Ant cuticular response to phthalate pollution

Abstract: Phthalates are common atmospheric contaminants used in the plastic industry. Ants have been shown to constitute good bioindicators of phthalate pollution. Hence, phthalates remain trapped on ant cuticles which are mostly coated with long-chain hydrocarbons. In this study, we artificially contaminated Lasius niger ants with four phthalates: dibutyl phthalate (DBP), diisobutyl phthalate (DiBP), di(2-ethylhexyl) phthalate (DEHP), and benzyl butyl phthalate (BBP). The first three have previously been found on ants in nature in Touraine (France), while the fourth has not. The four phthalates disappeared rapidly (less than 5 days) from the cuticles of live ants. In contrast, on the cuticles of dead ants, DEHP quantities remained unchanged over time. These results indicate that phthalates are actively absorbed by the cuticles of live ants. Cuticular absorption of phthalates is nonspecific because eicosane, a nonnatural hydrocarbon on L. niger cuticle, was similarly absorbed. Ants are important ecological engineers and may serve as bioindicators of ecosystem health. We also suggest that ants and more generally terrestrial arthropods may contribute to the removal of phthalates from the local environment.

Influence of oily vehicles on fetal testis and lipid profile of rats exposed to di-butyl phthalate

Abstract: It has been hypothesized that oils containing high levels of omega-3 polyunsaturated fatty acids, such as canola and fish oil, could counteract some of the adverse effects induced by phthalates. In the present study, the influence of different oily vehicles on di-butyl phthalate (DBP)-induced testicular toxicity and lipid profile was investigated. Pregnant Wistar rats were treated by oral gavage from gestation days 13 to 20 with DBP (500 mg/kg/day) diluted in three different vehicles: corn, canola or fish oil. Male fetuses were analyzed on gestation day 20. DBP exposure lowered intratesticular testosterone levels and anogenital distance, regardless of the vehicle used. The percentage of seminiferous cords containing multinucleated gonocytes and cord diameter was increased in DBP-exposed groups, compared with vehicle controls, with no difference between the three DBP-exposed groups. Clustering of Leydig cells was seen in all DBP groups. Lipid profile indicated that administration of canola and fish oil can increase the content of omega-3 fatty acids in rat testis. However, content of omega-3 was diminished in DBP-treated groups. Overall, our results indicate that different oily vehicles did not alter fetal rat testicular toxicity induced by a high DBP dose.

Silicon dioxide–poly(dimethylsiloxane) with a bilayer structure, incorporating multi-walled carbon nanotubes, supported on stainless steel wire as a solid-phase microextraction fiber for the determination of trace phthalate esters in drinking water samples

Abstract: Silicon dioxide–poly(dimethylsiloxane) with a bilayer structure, incorporating multi-walled carbon nanotubes, supported on stainless steel wire were prepared by a sol–gel method. This was used as a novel solid-phase microextraction (SPME) fiber in the determination of four phthalate esters (i.e., dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), di-2-ethylhexyl phthalate (DEHP)) in drinking water samples. The reaction mechanism of the sol–gel coating process was discussed and confirmed by IR spectra and scanning electron microscopy (SEM). The SPME experimental conditions such as the desorption temperature and time, extraction temperature and time, agitation and the salt effect were optimized. Compared with commercial fibers (polyacrylate (PA), polydimethylsiloxane (PDMS) and divinylbenzene–carboxen–polydimethylsiloxane (DVB–CAR–PDMS)), the novel fiber exhibited better film forming ability, higher thermal stability, higher extraction efficiency, and longer life time. Under the optimized conditions, the detected signals showed good linearity with the concentrations of DMP and DBP in the range from 0.1 to 100 μg L−1, and those of DEP and DEHP from 0.1 to 300 μg L−1. Based on a signal to noise ratio (S/N) of 3, the detection limits of DMP, DEP, DBP and DEHP were estimated to be 0.01, 0.02, 0.01 and 0.02 μg L−1, respectively. All calibration curves were found to have good linearity with the correlation coefficients (r2) which were greater than 0.998. The precision (RSD) of the system, measured by six repeated determinations of the analytes at 10 μg L−1 were in the range of 5.67–12.2%. The recoveries of real samples ranged from 85.27% to 109.3%.

Slow-injection ultrasound-assisted emulsification-microextraction for determination of phthalate esters in water.

Abstract: A type of ultrasound-assisted emulsification‐microextraction (USAEME) was applied for the extraction and determination of four phthalate esters (e.g., dimethyl phthalate, diethyl phthalate, dibutyl phthalate and benzyl butyl phthalate) in aqueous samples prior to quantification using HPLC-UV. The simultaneous injection of the extraction solvent and ultrasonication of the mixture results in an efficient extraction with the extractant well-dispersed in the sample. The parameters affecting the experimental results were analyzed and optimized through the design of the experiment. Using a central composite face-centered design, the results of 28 experimental data points were analyzed and validated. An optimal set of operating conditions was obtained using 40 mL of 1,1,2,2-tetrachloroethane and 1% NaCl subjected to 2.0 min of ultrasonication under natural pH. Under optimized conditions, the extractions resulted in analyte recoveries of 75‐87% and high enrichment factors of 356‐415. The calibration curves were linear, and the correlation coefficients ranged from 0.9992 to 0.9997 at concentrations of 5 to 300 m gL 21 . The RSDs (n 5 5) were 5.6‐7.9%. The limits of detection for the four phthalate esters ranged from 0.26 to 1.46 m gL 21 .

Identification of Thyroid-Receptor Antagonists in Water from the Guanting Reservoir, Beijing, China

Abstract: Thyroid hormone (TH) has long been known to be essential for normal brain development in both humans and animals, and increasing evidence suggests that environmental components may disrupt TH signaling. In the present study, two-hybrid yeast bioassay and chemical analysis were used to evaluate and identify thyroid-receptor (TR) disruptors in water from the Guanting Reservoir, Beijing, China. Modified yeast bioassay showed that the water samples could affect TH signaling. The bioassay-derived amiodarone hydrochloride equivalents ranged from 33.8 ± 3.3 to 308.5 ± 31.8 µg/L. Solid-phase extraction was used to separate the organic extracts, which were subjected to bioassay and chemical analysis. The organic extracts significantly antagonized the TR, which accounted for >86.0 % of the total effects. Thus, organic extracts may play a major role in the TR-disruption activity of the water. Phenols, organochlorine pesticides, and phthalate esters were detected in the organic extracts. Chemical analysis and toxic-equivalent calculation showed that a major cause of the TR antagonism of the water was dibutyl phthalate (80.1 to 122.7 %).