Diethyl phthalate (DEP)

Project ID

1097

Category

IRIS

Added on

Jan. 7, 2010, 11:28 a.m.

Search the HERO reference database

Query Builder

Search query
Journal Article

Abstract  Di(2-ethylhexyl)phthalate and 33 other phthalates, ethylhexanol derivatives, and related chemicals were tested for mutagenicity in Salmonella typhimurium strains TA98, TA100, TA1535, and TA1537 without metabolic activation and in the presence of rat and hamster liver S-9 metabolic activation systems. No mutagenic activity was seen with any of the chemicals tested.

Journal Article

Abstract  Neurotoxicity has been described in workers exposed to solvents, PCBs, certain metals, and polyaromatic hydrocarbons but not often in residents near refineries or factories. We compared the neurobehavioral performance of residents near a plant that reprocessed used motor oil and chemical waste from 1966?1983 to referents from beyond the plant's modeled air dispersal and water drainage zones. Neurophysiological and psychological tests, a Profile of Mood States (POMS) and a symptom questionnaire were administered to 131 subjects exposed at the site who were matched for age, sex, and ethnicity 2:1 with 66 unexposed subjects from 35 km away. Test scores were adjusted for a 1.4-year difference in educational attainment by coefficients from regression equations but not for income as the latter coefficients were not significant. Exposed subjects were significantly impaired for body balance (sway speed) and simple and two choice visual reaction time as compared to referents. Blink reflex latency (R-1) and eye closure speed were normal in both groups. Cognitive function in the exposed was impaired as measured by Culture Fair and by block design from the WAIS. Placing pegs in a grooved board and making of trails (A and B) were also impaired. Group differences in recall and memory were not significant. The exposed group's symptom frequencies and POMS scores for depression, anger, confusion, tension, and fatigue were elevated indicating depression. Confounding from medical and neurological disorders or occupational exposures was minimal. Subjects exposed residentially for up to 17 years to chemicals dispersed from a waste oil reprocessing plant showed neurophysiological and neuropsychological impairment.

Journal Article

Abstract  The testicular effects produced by di(2-ethylhexyl) phthalate (DEHP) in the rat, characterized by a decrease in the relative organ weight and histological changes in the seminiferous tubules, can also be produced by di-n-butyl, di-n-pentyl and di-n-hexyl phthalates. The corresponding monoesters of these compounds, formed in vivo as a result of the action of nonspecific esterases in the intestinal mucosa and other tissues, were equally effective in inducing testicular damage. Phthalate-induced testicular injury was accompanied by a decrease in the zinc content in the gonads and in increased urinary excretion of this element. Exposure of preparations of rat seminiferous tubule cells in culture to monophthalates capable of producing testicular injury resulted in a dose-related detachment of germinal cells from Sertoli cells in a manner similar to the effect seen in the intact animal. This in vitro system may find application in the elucidation of the toxic mechanisms involved in phthalate-induced testicular injury and in screening compounds likely to act in a manner similar to phthalates.

Book/Book Chapter

Abstract  In summary, the EPA has begun to look critically at the induction of certain types of tumors in certain species, including liver tumors in mice. The controversy over the use of such tumor data in assessing the cancer risk for humans has been going on for some time. The present agency policy is to downgrade the weight of evidence for such data under certain conditions. Review of the cancer risk assessments for the 109 chemicals that the agency has formally verified shows that a variety of chemicals yield liver tumors in mice. However, one group of substances that consistently produced such tumors was chlorinated compounds (84%). Many of these compounds not only induced liver tumors in mice but also induced liver tumors in rats and/or other types of tumors in mice and rats. However, several of the chlorinated compounds produced only mouse liver tumors. Another group of compounds that often induced liver tumors in mice was nitrogen-containing compounds (aromatic amines, hydrazines, nitrosamines). These latter substances tended to not only induce liver tumors in mice but also a variety of other tumor types in a variety of species. Mouse liver tumor data have played a major role in the classification of substances in categories B2 and C. Fifty-six percent of the chemicals in category B2 and 40% in category C were classified based at least partially on the use of mouse liver tumor data. In addition, 21 of the 29 category B2 chemicals that produced liver tumors in mice and 5 of the 8 category C chemicals are chlorinated compounds. These two results indicate the importance of chlorinated compounds to the agency, and therefore, the importance of mouse liver tumor data in agency cancer risk assessments.

DOI
Journal Article

Abstract  Three kinds of particulate matter were collected: diesel and gasoline exhaust particles emitted directly from exhaust nozzle, and suspended particulate matter (SPM) near the traffic route. Soxhlet extraction was performed on each sample. By gas-chromatograph–mass spectrometer (GC–MS) analysis of these extracts, di-ethyl phthalate and di-n-butyl phthalate were detected from the extract of SPM and diesel exhaust particles (DEPs). Because these phthalates were sometimes suspected as contamination, time-of-flight secondary ion mass spectrometry (TOF-SIMS) measurements were also performed on the samples collected at the same environment. By comparing obtained spectra, it is clear that these environmental endocrine disrupters (EEDs) were adsorbed on DEP surface. Thus, we concluded that the combination of conventional method and TOF-SIMS measurement is one of the most powerful techniques for analyzing the toxic air pollutants adsorbed on SPM surface.

WoS
Book/Book Chapter

Abstract  It is important to know both the emission and the sorption behavior of materials when constructing or renovating buildings in order to avoid material related indoor climate problems. With a general, low-cost test method, the sink effect of materials under normal conditions can be incorporated as information in an indoor climate labeling system for materials. Reconditioned samples of waterborne paint applied on tinned steel plates and carpet were placed in small test chambers at a controlled air exchange rate and mean air velocity. The sorption behavior of the materials was studied, while ambient air from a recently renovated office environment was passed through the chambers. The desorption of VOCs from the test samples was analyzed chemically and by sensory evaluation. The results showed a correlation between the chamber concentration in the desorption phase expressed as the percentage of the concentration in the office air and the gas chromatographic retention times of the VOCs (using a semipolar column). The results are used to propose a general test method for assessing the sink effects of materials used in the indoor environment. A mixture of pollutants with affinities to indoor surfaces is proposed for adsorption testing under controlled environmental conditions. A mathematical model of the distribution of emitted VOCs between indoor air and sinks is proposed. It is possible to calculate the impact of the sinks on the indoor air quality by comparison within door relevant thresholds for odor and mucous membrane irritation.

Journal Article

Abstract  Toxicity tests were conducted with sheepshead minnows to develop a data base from which water quality criteria could be established and to help determine priorites for further reseach efforts. Chemicals were generally those used by industry in relatively large quantities that pose potential or suspected environmental hazards, such as, chlorinated benzenes, phenols, and phthalates. The acute toxicity of the 54 chemicals varied widely. The most toxic chemical groups were the chlorinated phenols and the chlorinated benzenes with 96-h LC50's (based on nominal concentrations) ranging from 1.7-5.4 ppm and 0.8-21 ppm, respectively. The most toxic chemical tested appeared to be 1,2,4,5-tetrachlorobenzene with a 96-h LC50 of 0.8 ppm (95% confidence limits of 0.7-1.1 ppm). The 96-h LC50 for pentachlorobenzene was the same (0.8 ppm; 95% confidence limits of 0.4-1.8 ppm), but its effect early in the exposure was not as severe as the effect of 1,2,4,5-tetrachlorobenzene. The majority of the chemicals had 96-h LC50's in the range of 10-500 ppm and were considered to be slightly toxic to practically nontoxic. Ten of the chemicals had no apparent effect at highest concentrations tested. (JMT)

Journal Article

Abstract  Phthalates are used as plasticizers and solvents in industrial, medical and consumer products; however, occupational exposure information is limited. We sought to obtain preliminary information on occupational exposures to diethyl phthalate (DEP), di-n-butyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) by analyzing for their metabolites in urine samples collected from workers in a cross-section of industries. We also obtained data on metabolites of dimethyl phthalate (DMP), benzylbutyl phthalate (BzBP), di-isobutyl phthalate and di-isononyl phthalate. We recruited 156 workers in 2003-2005 from eight industry sectors. We assessed occupational contribution by comparing end-shift metabolite concentrations to the US general population. Evidence of occupational exposure to DEHP was strongest in polyvinyl chloride (PVC) film manufacturing, PVC compounding and rubber boot manufacturing where geometric mean (GM) end-shift concentrations of DEHP metabolites exceeded general population levels by 8-, 6- and 3-fold, respectively. Occupational exposure to DBP was most evident in rubber gasket, phthalate (raw material) and rubber hose manufacturing, with DBP metabolite concentrations exceeding general population levels by 26-, 25- and 10-fold, respectively, whereas DBP exposure in nail-only salons (manicurists) was only 2-fold higher than in the general population. Concentrations of DEP and DMP metabolites in phthalate manufacturing exceeded general population levels by 4- and >1000-fold, respectively. We also found instances where GM end-shift concentrations of some metabolites exceeded general population concentrations even when no workplace use was reported, e.g. BzBP in rubber hose and rubber boot manufacturing. In summary, using urinary metabolites, we successfully identified workplaces with likely occupational phthalate exposure. Additional work is needed to distinguish occupational from non-occupational sources in low-exposure workplaces.

WoS
Journal Article

Abstract  The use of solid phase extraction and capillary GLC provides the basis for selective determination of phthalate ester plasticizers in rivers and marine water samples. Of the several solvent ratios (methanol in dichloromethane) that were tried for selective elution of phthalate esters from the C18 solid phase glass catridge, the 50/50 ratio, CH3OH in CH2Cl2 (v/v) gave the best result. The method was tested on river and marine water samples that receive effluent from industries that use phthalate esters. The rivers and marine water samples are grossly polluted as several phthalate esters, for example, dimethyl(DMP), diethyl(DEP), dibutyl(DBP) and diethylhexyl( DEHP) were found present at 0.03 -2 306+/-9.4 mug l(-1). A study on uncontaminated water was done to establish bank levels.

Journal Article

Abstract  Phthalates are used ubiquitously and human exposure is widespread. Some phthalates are anti-androgens and have to be regarded as reproductive and developmental toxicants. In the Duisburg birth cohort study we examine the associations between hormonally active environmental agents and child development. Here we report the concentrations of 21 primary and secondary phthalate metabolites from seven low molecular weight (LMW) phthalates (DMP, DEP, BBzP, DiBP, DnBP, DCHP, DnPeP) and five high-molecular weight (HMW) phthalates (DEHP, DiNP, DiDP, DPHP, DnOP) in 208 urine samples from 104 mothers and their school-aged children. Analysis was performed by multidimensional liquid chromatography coupled to tandem mass spectrometry (LC/LC-MS/MS), using internal isotope-labeled standards. In both children and mothers, 18 out of 21 phthalate metabolites were detected above the limits of quantification (between 0.2 and 1.0μg/l) in nearly all urine samples. Among the LMW phthalates, the excretion level (geometric mean) of the ΣDiBP metabolites was most prominent in children (103.9μg/l), followed by ΣDnBP (56.5μg/l), and MEP (39.1 μg/l). In mothers ΣDiBP (66.6μg/l) was highest, followed by MEP (50.5μg/l), and ΣDnBP (36.0μg/l). Among the HMW phthalates, ΣDEHP was highest in children and mothers (55.7/28.9μg/l). Compared to reference values derived from the German Human Biomonitoring Commission, children's metabolite concentrations were within background levels, whereas for mothers considerably higher exposure to the LMW phthalates DnBP and DiBP, and the HMW phthalate DEHP was detected (MiBP: 10.7%; MnBP: 11.7%; ΣDEHP: 23.3% of the samples were above the reference values). The LMW metabolites from DMP, DiBP, and DnBP, and the HMW metabolites from DEHP and DiNP were correlated between the mothers and children, probably indicating shared exposure in the immediate surrounding environment. Children showed higher excretion levels for most of the secondary metabolites than mothers, confirming previous findings on higher oxidized metabolite levels in children. The LMW metabolites ΣDiBP, ΣDnBP, and MMP, and the HMW metabolites ΣDEHP were negatively associated with children's age. The LMW metabolites ΣDiBP, ΣDnBP, and MBzP were inversely associated with body mass index of the children. The LMW ΣDiBP metabolites revealed a significant association with nicotine metabolites in urine from both children and mothers. Further analyses are ongoing to study long-term phthalate exposure and the associations with puberty outcome in these children.

Journal Article

Abstract  Phthalate esters, commonly used as plasticizers, show anti-androgenic activity and cause male reproductive malformation in experimental animals. However, the effects of prenatal exposure to phthalate esters in humans have not been extensively studied. The purpose of this study was to examine the relationship between prenatal exposure to phthalate esters and the anogenital distance (AGD) as a reproductive endpoint in human male newborns. Spot urine samples were collected from 111 Japanese pregnant women after obtaining their informed consent. Seven urinary phthalate ester metabolites were determined by high performance liquid chromatography-tandem mass spectrometry. Urinary isoflavones concentrations were measured as possible covariates because their oestrogenicities and high exposure levels among Japanese have the potential to affect male genital development. Birth outcomes and AGD, the distance from the centre of the anus to external genitalia, were measured for their male newborns. In a multiple regression model, the log-transformed mono-2-ethylhexyl phthalate concentration (specific gravity-corrected) was negatively significant, and maternal smoking status was positively significant, in explaining anogenital index (AGI) when potential covariates were controlled for. Urinary isoflavones did not significantly contribute to AGI in any models. Our results suggest that prenatal exposure to di(2-ethylhexyl) phthalate affects reproductive development in human males.

Journal Article

Abstract  Phthalates have been identified as endocrine active compounds associated with developmental and reproductive toxicity. The exposure to phthalates in premenstrual Egyptian females remains unknown. The objective of this study was to characterize phthalate exposure of a potentially vulnerable population of premenstrual girls from urban and rural Egypt.

We collected one spot urine sample from 60 10-13 year old females, 30 from rural Egypt, and 30 from urban Egypt from July to October 2009. Samples were analyzed for 11 phthalate metabolites. Additionally, we collected anthropometrics as well as questionnaire data concerning food storage behaviors, cooking practices, and cosmetic use. Phthalate metabolite concentrations were compared between urban and rural Egyptians as well as to age and gender matched Americans.

Monoethyl phthalate (MEP), was detected at the highest concentration in urine of Egyptian girls (median: 43.2 ng/mL in rural, 98.8 ng/mL in urban). Concentrations of urinary metabolites of di-(2-ethylhexyl) phthalate and dibutyl phthalate were comparable between Egyptians and age matched US girls. Storage of food in plastic containers was a statistically significant predictor of urinary mono-isobutyl phthalate (MiBP) concentrations when comparing covariate adjusted means.

Urinary concentrations of phthalate metabolites were similar in Egyptian and US populations, suggesting that phthalate exposure also occurs in developing nations. Dietary intake is likely an important route of exposure to phthalates in both urban and rural populations.

Journal Article

Abstract  Phthalate and phenol exposure is prevalent among the general population and of potential concern for pregnant women and children because of their suspected susceptibility to endocrine effects.

To evaluate the extent of exposure to several phthalates and phenols in a sample of Spanish pregnant women - according to their individual characteristics (age, social class, education, and body mass index) - and children who participated in the INMA - Infancia y Medio Ambiente (Environment and Childhood) project.

One spot urine sample was taken during the third trimester of pregnancy from 120 pregnant women and from 30 4-year old children belonging to 5 Spanish birth cohorts, and analyzed for 11 phthalate metabolites and 9 phenols.

Three metabolites of di(2-ethylhexyl) phthalate, mono-2-ethyl-5-carboxypentyl phthalate, mono-2-ethyl-5-hydroxyhexyl phthalate, and mono-2-ethyl-5-oxohexyl phthalate; two metabolites of dibutyl phthalates, mono-isobutyl phthalate and mono-n-butyl phthalate; monoethyl phthalate (MEP), the main metabolite of diethyl phthalate; and two phenols, methyl paraben (M-PB) and 2,5-dichlorophenol were detected in the urine samples of all women. The highest urinary concentrations were for MEP and M-PB. Urinary concentrations of all phthalate metabolites and of 2,4-dichlorophenol, 2,5-dichlorophenol, and bisphenol A were lower in the pregnant women than in the children. Among women, a positive relationship with social class and education was shown for most of the phthalate metabolites and phenols. Almost all phthalate metabolites varied by region even after adjusting for social class and education.

Phthalate and phenol exposures are prevalent in a group of pregnant women and young children, two susceptible populations, and these exposures might be positively related to social class.

Journal Article

Abstract  Phthalates are widely used as plasticizers to soften and increase the flexibility in polyvinyl chloride plastics, but they can leach into the surrounding environment. There is sufficient evidence in rodents that phthalate exposure causes developmental and reproductive toxicity. The curated interactions between 16 phthalates and genes/proteins were obtained from Comparative Toxicogenomics Database (CTD), and a total of 445 interactions between the five most frequently curated phthalates (DEHP/MEHP and DBP/BBP/MBP) and 249 unique genes/proteins were found. The GeneOntology, pathways and networks of these 249 unique genes/proteins were fully analyzed. The pathways and networks of top 34 genes/proteins were found to be very similar to those of the 249 unique genes/proteins. Thus, the top 34 genes/proteins may serve as molecular biomarkers of phthalate toxicity. The top three phthalate toxicity categories were found to be cardiotoxicity, hepatotoxicity and nephrotoxicity, and the top 20 diseases included cardiovascular, liver, urologic, endocrine and genital diseases.

Journal Article

Abstract  Although changes in diet and physical activity are undoubtedly key causal factors related to the increase in obesity, there is growing interest in the possibility that endocrine disrupting chemicals (EDCs) may affect obesity-related pathways by altering cell signalling involved in weight and lipid homeostasis. Proposed mechanisms that could underlie associations between EDCs and obesity include effects on thyroid and steroid hormones, and activation of peroxisome proliferator-activated receptors, which play a major role in adipocyte differentiation and energy storage. Most evidence supporting the hypothesis that EDCs affect obesity comes from laboratory studies. We summarize the limited epidemiological literature on the topic, including prospective studies of human prenatal exposure to EDCs. We also present findings from a cross-sectional study of levels of six phthalate metabolites and body mass index (BMI) and waist circumference (WC), using data from the U.S. National Health and Nutrition Examination Survey. We found positive associations between BMI and WC among adult males for most phthalate metabolites. For example, in males aged 20-59, the adjusted mean BMI across quartiles of mono-benzyl phthalate was 26.7, 27.2, 28.4, 29.0 (p-trend = 0.0002). In females, BMI and WC increased with quartiles of mono-ethyl phthalate in 12-19 year olds (adjusted mean BMI = 22.9, 23.8, 24.1, 24.7, p-trend = 0.03), and a similar but less strong pattern was seen in 20-59 year olds. By contrast, higher levels of mono-2-ethylhexyl phthalate were associated with lower BMI in adolescent girls and females aged 20-59. This exploratory analysis found several associations between phthalate metabolites and obesity, including notable differences by gender. However, the cross-sectional data are a limitation. Additional prospective studies of the association between exposures to EDCs, especially during development, and obesity are warranted. As this field of research advances, there are challenging methodological questions that must be considered by both epidemiologists and toxicologists.

Journal Article

Abstract  We developed a highly sensitive method for the quantitative detection of nine phthalate ester metabolites in human serum. This method requires denaturation of the serum enzymes immediately after blood collection to avoid the hydrolysis of the contaminant diester parent compounds introduced during blood collection and storage. Before analysis, the samples were subjected to an enzymatic deconjugation to hydrolyze the glucuronidated phthalate monoesters and a solid-phase extraction to isolate the monoesters from other serum components. The extracts were analyzed using reversed-phase high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. The limits of detection of all nine phthalate monoesters in serum were in the low nanogram-per-milliliter range (0.6-1.3 ng/mL). Stable isotope-labeled internal standards for all analytes were used to improve precision and for recovery corrections. This highly selective method permits the analysis of phthalate monoesters without interferences resulting from the hydrolysis of the ubiquitous contaminant phthalate diesters by serum enzymes. In addition, it allows the direct measurement of the active phthalate monoester metabolites reportedly responsible for the reproductive and developmental toxicity of certain phthalates.

DOI
Book/Book Chapter

Abstract  This book deals with the safe and legal handling of hazardous materials and waste from the manufacturer's plant through the storage, transportation and distribution channels to the user, and, ultimately, to the disposal of the product or waste materials. There is increasing pressure today from the public, academia, government at all levels, and industry to improve the handling and management of hazardous materials. A knowledge of the methods required to safely handle and manage those materials in all of their various aspects, together with an understanding of the many governmental regulations that apply to those materials in the various stages of the distribution chain, is absolutely essential to their proper handling and disposal. Efficient handling and the safe management of hazardous materials requires an expertise in the skills and techniques of the latest innovations, which in turn are often based upon the firm foundation of data and experience in those areas. Personal and public safety require that the information concerning hazardous materials be disseminated as widely as possible. This document should not be used to determine compliance with the u.s. DOT hazardous material regulations, or with any other regulations imposed by loca\, State, or Federal regulatory bodies.

Journal Article

Abstract  Il y a environ 50 000 à 60 000 composés chimiques utilisés communément à des fins techniques. Certains d'entre eux sont toxiques et leur rejet dans l'environnement peut constituer une menace pour l'équilibre des écosystèmes aquatiques et pour la santé humaine. Plusieurs listes de substances dangereuses, appelées également polluants chimiques prioritaires, ont ainsi été établies par des organismes nationaux ou internationaux, notamment par l'EPA aux Etats-Unis, la CEE en Europe, l'Organisation Mondiale de la Santé (OMS). La nécessité de protéger les milieux aquatiques et la santé humaine a par ailleurs amené le développement de standards, de critères de qualité des eaux naturelles et des eaux potables, vis-à-vis de ces contaminants chimiques. Les sources de pollution sont diverses, se partageant entre les sources localisées comme les effluents urbains et industriels et les sources diffuses comme les eaux de ruissellement en zones rurales et en zones urbaines et les retombées atmosphériques. Différentes processus biogéochimiques déterminent les mécanismes de transport et de transformation des polluants organiques dans le milieu aquatique, et la bioaccumutation dans les organismes vivants représente un important aspect de ce comportement. Une première évaluation de la qualité des eaux continentales (rivières, lacs, eaux souterraines) est effectuée en examinant les données recueillies à travers le réseau de surveillance mondiale de la qualité de l'eau (GENS/EAUX) mis en place par deux organismes des Nations Unies, l'OMS et le PNUE. D'autres sources d'informations, publiées dans la littérature scientifique, ont été également utilisées pour évaluer les niveaux de concentrations observés pour différents groupes de polluants organiques dans les eaux naturelles et les eaux potables. La plupart des données disponibles proviennent d'un nombre limité de pays industriels d'Amérique du Nord, d'Europe et du Japon. Il y a une dramatique absence d'informations concernant la qualité chimique des eaux continentales dans les pays les moins développés d'Afrique, d'Amérique Latine et d'Asie. A l'heure actuelle, la stratégie de surveillance des polluants chimiques à l'échelle mondiale est donc loin d'être réellement satisfaisante.

DOI
Journal Article

Abstract  Objective To investigate the coexistence of endometriosis in women presenting with symptomatic leiomyomas.Design Retrospective study.Setting Tertiary university medical center.Patient(s) We reviewed the medical records of 131 patients who underwent laparoscopic myomectomy or hysterectomy. All patients were consented for possible concomitant diagnosis and treatment of endometriosis.Intervention(s) All patients underwent laparoscopic myomectomy or hysterectomy.Main Outcome Measure(s) The main outcome measure of the study was the presence or absence of endometriosis.Result(s) Of the 131 patients, 113 were diagnosed with endometriosis and fibroids, while 18 were diagnosed with fibroids alone. Patients with fibroids were on average 4.0 years older than those with endometriosis and fibroids (41 vs. 45). Patients with both diagnoses were also more likely to present with pelvic pain and nulliparity than those with fibroids alone.Conclusion(s) An overwhelming majority of patients with symptomatic fibroids were also diagnosed with endometriosis. Overlooking the concomitant diagnosis of endometriosis in these women may lead to suboptimal treatment of the patients. Further studies are needed to evaluate the impact of surgical treatments on symptom resolution.

Journal Article

Abstract  The pollution status and characteristics of PAEs (phthalate esters) were investigated in indoor air of offices, and PAEs of both gas-phase and particulate-phase were detected in all the samples. The concentration (sum of the gas phase and the particulate phase) was 4748.24ng/m(3), ranging between 3070.09 and 6700.14ng/m(3). Diethyl phthalate, dibutyl phthalate, and di(2-ethylhexyl) phthalate were the most abundant compounds, together accounting for 70% of the ∑6PAEs. Dividing the particulate-phase PAEs into four size ranges (<2.5, 2.5-5, 5-10, >10μm), the result indicated that PAEs in PM2.5 were the most abundant, with the proportion of 72.64%. In addition, the PAE concentration in PM2.5 correlated significantly with the total particulate-phase PAEs (R(2)=0.85). Thus, the amount of PAEs in PM2.5 can be estimated from the total amount of particulate-phase PAEs using this proportion. In a comparison between the offices and a newly decorated study room, it was found that pollution characteristics were similar between these two places. Thus, it is implied that the PAE concentration decreased by 50% 2yr after decorating.

Journal Article

Abstract  Aqueous solutions of diethyl phthalate (DEP) were oxidized by using ozone combined with Fenton reagents. The effects of operating parameters such as initial pH; initial concentration of DEP, H2O2 and Fe(2+); [H2O2]0/[Fe(2+)]0 ratio and O3 dosage on the degradation rates of DEP were investigated. The results showed that DEP degradation is strongly dependant on the pH; initial concentrations of the phthalate, H2O2 and Fe(2+); [H2O2]0/[Fe(2+)]0 ratio and O3 dosage. The addition of H2O2 and Fe(2+) ions was effective to achieve almost 98% degradation of 200 mg L(-1) of DEP in about 40 min using a dose of O3 = 45 g m(-3) NTP; [H2O2]0 = 2.5 × 10(-2) mol L(-1) and [Fe(II)]0 = 5 × 10(-3) mol L(-1), as compared to over 60 min by using O3 and Fenton processes applied separately. DEP degradation followed apparent pseudo-first-order kinetics under ozonation, Fenton's reagents oxidation and the combined ozonation/Fenton reagents oxidation process. The overall reaction rates were significantly enhanced in the O3/Fe(2+)/H2O2 oxidation system, and allows achieving 100% degradation of DEP (100 mg L(-1)) in 30 min of reaction time. The notable decrease in DEP removal rate observed in the presence of a radical scavenger indicates that there was an obvious synergetic effect in the combined ozonation/Fenton reagent process most likely because ozonation could accelerate Fenton reagents to generate hydroxyl radical HO•. Thus, the reaction between DEP and HO• proceeds mainly in the bulk of the aqueous phase. Under optimal conditions, the O3/Fe(2+)/H2O2 system oxidation was the most effective in DEP removal in water.

Journal Article

Abstract  Phthalic acid esters (PEs) were preconcentrated from cleaning products, detergents and cosmetics using ultrasound assisted extraction (UAE) in the presence of acetonitrile, and then submitted to dispersive liquid-liquid microextraction (DLLME). For DLLME, 3mL of acetonitrile extract, 150μL carbon tetrachloride and 10mL aqueous solution were used. The enriched organic phase was evaporated, reconstituted with 25μL acetonitrile and injected into a liquid chromatograph with a mobile phase (acetonitrile:10mM ammonium acetate, pH 4) under gradient elution. Detection was carried out using both diode-array (DAD) and electrospray-ion trap-tandem mass spectrometry (ESI-IT-MS/MS) in the multiple reaction monitoring mode (MRM) of the positive fragment ions. Quantification was carried out using matrix-matched standards. Detection limits were in the range 0.04-0.45ngmL(-1) for the six PEs considered. The recoveries obtained were in the 84-124% range, with RSDs lower than 10%. Thirty three different cleaning products were analyzed. The most frequently found compound was diethyl phthalate.

Journal Article

Abstract  Here, a novel technique is described for the extraction and quantitative determination of six phthalate esters (PAEs) from soils by gas purge microsyringe extraction and gas chromatography. Recovery of PAEs ranged from 81.4% to 120.3%, and the relative standard deviation (n=6) ranged from 5.3% to 10.5%. Soil samples were collected from roadsides, farmlands, residential areas, and non-cultivated areas in a non-industrialized region, and from the same land-use types within 1km of an electronics manufacturing facility (n=142). Total PAEs varied from 2.21 to 157.62mgkg(-1) in non-industrialized areas and from 8.63 to 171.64mgkg(-1) in the electronics manufacturing area. PAE concentrations in the non-industrialized area were highest in farmland, followed (in decreasing order) by roadsides, residential areas, and non-cultivated soil. In the electronics manufacturing area, PAE concentrations were highest in roadside soils, followed by residential areas, farmland, and non-cultivated soils. Concentrations of dimethyl phthalate (DMP), diethyl phthalate (DEP), and di-n-butyl phthalate (DnBP) differed significantly (P<0.01) between the industrial and non-industrialized areas. Principal component analysis indicated that the strongest explanatory factor was related to DMP and DnBP in non-industrialized soils and to butyl benzyl phthalate (BBP) and DMP in soils near the electronics manufacturing facility. Congener-specific analysis confirmed that diethylhexyl phthalate (DEHP) was a predictive indication both in the non-industrialized area (r(2)=0.944, P<0.01) and the industrialized area (r(2)=0.860, P<0.01). The higher PAE contents in soils near the electronics manufacturing facility are of concern, considering the large quantities of electronic wastes generated with ongoing industrialization.

Journal Article

Abstract  Cylindrotheca closterium, a marine benthic diatom, was inoculated on the surface of marine sediments spiked with diethyl phthalate (DEP) and dibutyl phthalate (DBP) to investigate the effects of benthic microalgae on the degradation of the contaminants. The elimination of DEP and DBP from unsterilized sediments with C. closterium (treatment BA) was compared with that from unsterilized sediments without C. closterium (treatment B), sterilized sediments with C. closterium (treatment A) and sterilized sediments without C. closterium (treatment N). The results showed that during the 8-day experiment, inoculation with C. closterium increased the removal rates of the contaminants from the sediments, and more significantly from the surface layer (top 0.5cm) of sediments than from the bottom layer of sediments. In the surface sediments, the first-order elimination rate constants (k) of DEP and DBP were in the order of treatment BA (2.098 and 0.309d(-1))>treatment B (0.460 and 0.256d(-1))>treatment A (0.216 and 0.039d(-1))>treatment N (nil (no data)), indicating that microbial degradation played a major role in the removal of the contaminants from the sediments. A similar trend was also observed in bottom sediments (0.444 and 0.165d(-1) in treatment BA, 0.329 and 0.194d(-1) in treatment B, 0.129d(-1) and nil in treatment A), but the difference of k values between treatments BA and B was relatively small. The positive effect of C. closterium on total phospholipid fatty acid (PLFA) content in sediments was observed, which was mainly related to the increase of biomass of aerobic bacteria as a result of improved sediment oxygenation and release of exudates (e.g. exopolysaccharides) by C. closterium. Moreover, Pearson correlation analysis showed a significant positive correlation between the elimination ratios of the contaminants and abundance of total aerobic bacterial PLFAs, suggesting that aerobic bacteria played a key role in C. closterium-promoted degradation of the contaminants in sediments.

  • <<
  • 6 of 126
  • >>
Filter Results