Abstract  BIOSIS COPYRIGHT: BIOL ABS. Following earlier work (Al-Omran & Preston, 1987) in which phthalate ester speciation was examined in laboratory studies, the present paper describes the results of an attempt to validate the results by field measurements in the River Mersey Estuary, Liverpool, UK. Samples of water, suspended solids and sediments were analysed for their phthalate ester content. Solid samples were also analysed for their carbon, organic carbon and lipid content. A comparison of the field and laboratory results confirms the association between diethylhexyl phthalate and small particles and shows that other phthalates tend to be associated with relatively coarse, lipid-rich particles. Partition coefficients between dissolved phthalate esters and suspended particles are calculated and compared with other laboratory studies.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM JAPAN

Abstract  Studies have shown that phthalate esters traverse the food web and can be found as the original ester in fish. However, concentrations are not expected to be magnified across the food web to a great extent since fish appear more capable of F degrading them than do in- vertebrates. Under conditions of continuous exposure, respiratory and dietary factors influence phthalate ester accumulation. Effects: Lethality: One of the major problems in testing the biological effects of phthalate esters in aqueous systems is their initial or sustained solubility in water The methodological details given in the studies reported allow few definitive statements concerning the actual ester concentrations used. Six phthalate esters have been studied for lethality, detailed studies for most of the organisms involved only DnBP. Lethal concentrations (LC50) for all the aquatic or- ganisms investigated range from 1 to 10 mg/1. The only noted lethal threshold is at a DnBP concentration of 0.5 mg/1 for rainbow trout (Salmo gairdneri). The data on the lethality of dimethylphthalate (DMP), diethylphthalate (DEP) and din-propylphthalate (DnPP) seem generally to fall within the same range as that for DnBP. In contrast, the values for DEHP lethal concentrations (LC50) are at least an order of magnitude higher than those for DnBP. The data for di-n-octylphthalate (DnOP) suggest that it is even less toxic than DEHP. Studies on the mortality of aquatic organisms exposed chroni- cally to phthalate esters are limited in number and difficult to interpret. The data for DnBP indicate that no threshold exists. Several effects of phthalate esters have been reported to occur at what may be considered an acutely lethal range of concentrations. Such effects cannot be truly classified as sublethal but are most probably manifestations of toxicity prior to actual death. Hence, effects such as suppression of respiration, failure of reproduction and survival of young, growth impairment,and depression of heartbeat, although usually considered as sublethal effects, were noted in experiments using acutely lethal concentrations of phthalate esters. Although the mechanisms are not known, DnOP, DEHP and di-iso-butylphthalate (DiBP) were found to suppress respira- tion in a soil not preincubated with phthalate esters. However, soil that had been preincubated did not undergo respiration suppression even at very high ester con- centrations. No variation in either the number of species of microorganisms or other responses, such as respiration, was found after the introduction of DEHP, phthalic acid, or 2-ethylhexanol into an intermittent flow-through hydrosoil. The number of larvae of brine shrimp (Artemia salina) hatched over 24 hours was reduced by 20 and 40 percent because of DEP and DnBP, respectively. No reduction was caused by DMP. There was a sufficient dosage (either in concentration or time) of these phthalate esters to allow for significant mortality in the early-hatching larvae. It has been reported that dietary phthalate esters have an effect upon the survival of zebrafish (Brachydamio rerio) fry. However, it is unclear whether the reduction in survival was due to the parent or the fry feeding on the DEHP in the diet. In addition, the variation in spawns and eggs per spawn may have been within the expected range of the species and the relationship to DEHP concentration was probably coincidental. The only studies that have examined the effects of phthalate esters on growth were carried out with some micro- organisms. The concentrations that inhibit growth are high, been shown to act as heartbeat depressors in goldfish (Cra- ssius auratus). Reductions of approximately 60% were recorded for 12 mg/l DnBP and 200 mg/l benzylbutylphthalate (BBP), respectively. A reduction of 33% was recorded for 200 mg/l DEHP. Sublethal Effects: Very little information is available on the sublethal effects of phthalate esters on aquatic organisms. Depression of reproduction in the water flea (Daphnia magna) has been observed. Di-(2-ethylhexyl)phthalate, in concentrations of 3, 10 an 30 ug/l, reduced egg laying over a 3-week period by 60, 70 and 80% respectively. The growth of rainbow trout fry, adult brook trout (Sulvelinus fontinalis) and fathead minnow fry was not sig- nificantly affected when the fish were exposed to low levels of DEHP; however, vertebral collagen content of bone and hydroxylproline content of collagen were altered. Steroid hormone biosynthesis in male Atlantic cod (Gradus morhus) was affected by DEHP at concentrations as low as 1 ug/g of tissue. The present criteria describing the sublethal effects of phthalate esters on aquatic organisms do not form an adequate scientific base on which to develop water quality objectives for the protection of aquatic life. (Shortened)

Abstract  Deodorants are one of the most frequently-used types of cosmetics and are a source of allergic contact dermatitis. Therefore, a gas chromatography - mass spectrometric analysis of 71 deodorants was performed for identification of fragrance and non-fragrance materials present in marketed deodorants. Furthermore, the sensitizing potential of these molecules was evaluated using structure activity relationships (SARs) analysis. This was based on the presence of 1 or more chemically reactive site(s), in the chemical structure, associated with sensitizing potential. Among the many different substances used to formulate cosmetic products (over 3500), 226 chemicals were identified in a sample of 71 deodorants. 84 molecules were found to contain at least 1 structural alert, and 70 to belong to, or be susceptible to being metabolized into, the chemical group of aldehydes, ketones and alpha,beta-unsaturated aldehydes, ketone or esters.

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)

Abstract  In a 90-day toxicity study in rats, di-(2-ethylhexyl)phthalate (DEHP) produced testicular atrophy. To characterise further the testicular toxicity of phthalate esters the effect of age on the induction of testicular atrophy has been examined as well as the reversibility of the lesions and the effects of certain other phthalate esters. Seminiferous tubular atrophy, comprising a loss of spermatids and spermatocytes, resulted when 4-week-old rats were given 10 daily doses of DEHP. In similarly treated 10-week old rats up to 50% of tubules were atrophic while the remainder were unaffected. No testicular damage was produced in 15 week-old rats. The lesion produced in 4-week-old rats was reversible whether treatment was stopped prior to, or continued until after the control rats had reached sexual maturity. Normal testicular weight and histology were restored within 12 and 20 weeks respectively. Of a series of di-n-alkyl phthalates from dimethyl to di-n-octyl, the butyl, pentyl and hexyl esters produced testicular lesions similar to DEHP. The testicular effects of DEHP were not influenced by simultaneous administration of testosterone or follicle stimulating hormone (FSH). The mechanism by which phthalate esters exert their effects is discussed in the context of a possible action on Sertoli cell function.

Abstract  We present an impulsive stimulated scattering test of the "shoving model" of the glass transition and of the correlation between the fragility index and the ratio of instantaneous elastic moduli of eight supercooled liquids. Samples of triphenyl phosphite, DC704 (tetramethyl tetraphenyl trisiloxane), m-fluoroaniline, Ca(NO(3))(2)4H(2)O, diethyl phthalate, propylene carbonate, m-toluidine, phenyl salicylate (salol), 2-benzylphenol, and Santovac 5 (5-phenyl 4-ether), were cooled to their respective glass transition temperatures and the elastic moduli directly measured at the highest accessible shear frequencies. The shear modulus was then measured every 2 K as deeply as permitted into the liquid state for all liquids except propylene carbonate. Our results, in conjunction with dynamical relaxation data for these liquids obtained from the literature, lend credence to the notion that the dynamics of the glass transition are governed by the evolution of the shear modulus but do not suggest a strong correlation between the fragility index and the ratio of the elastic moduli.

Abstract  Effects of polyvinyl-chloride (9002862) (PVC) resins and their additives on human serum protein, guinea-pig complement, blood grouping antibodies (neutral and immune), human erythrocytes, tissue cultures, and developing chick embryos were studied. Additives included 46 heat stabilizers, 45 plasticizers, and 5 PVC resins. A total of 120 finished products was prepared from these ingredients. Various components had adverse reactions, and some which were used for finished plastics had no adverse effects. In general, many of the heat stabilizers and inhibitors with heavy metals had a destructive effect on guinea-pig complement. Among finished plastics those containing dimethylphthalate (131113), dibutyl-suberate (16090770), dimethyl-sebacate (106796), and butyl-oleate (142778) produced toxic changes in human red blood cells. Dibutyl-suberate and some phthalates also interfered with the blood grouping antibodies. Phthalates were found to produce reduced hatch rates, neurological abnormalities, and increased chick mortality. The data indicated possible harmful qualities of certain plastics components on stored biological material, such as serum proteins, red blood cells, and antiserum. The authors conclude that plastics used for containers, dispensers, and closures for biological products must be composed of ingredients that will not damage the product during storage.

Abstract  15 hazardous industrial waste samples were evaluated for mutagenicity in the Salmonella plate-incorporation assay using strains TA98 and TA100 in the presence and absence of Aroclor 1254-induced rat liver S9. Dichloromethane/methanol extracts of the crude wastes were also evaluated. 7 of the crude wastes were mutagenic, but only 2 of the extracts of these 7 wastes were mutagenic; extracts of 2 additional wastes also were mutagenic. In addition, 10 of the crude wastes were administered by gavage to F-344 rats, and 24-h urine samples were collected. Of the 10 raw urines evaluated, 3 were mutagenic in strain TA98 in the presence of S9 and β-glucuronidase. The 3 crude wastes that produced these 3 mutagenic urines were, themselves, mutagenic. Adequate volumes of 6 of the 10 raw urines were available for extraction/concentration. These 6 urines were incubated with β-glucuronidase and eluted through Sep-Pak® C18 columns; the methanol eluates of 3 of the urines were mutagenic, and these were the same 3 whose raw urines also were mutagenic. In general, the C18/methanol extraction procedure reduced the cytotoxicity and increased the mutagenic potency of the urines. To our knowledge, this is the first report of the mutagenicity of urine from rodents exposed to hazardous wastes. Based on the present results, the use of only strain TA98 in the presence of S9 might be adequate for general screening of hazardous wastes or waste extracts for genotoxicity. The urinary mutagenesis assay does not appear to be a useful adjunct to the Salmonella assay for screening hazardous wastes. The problems associated with chemically fractionating diverse types of hazardous wastes for bioassay are also discussed.

Abstract  Two adsorbent solid phase microextraction (SPME) fibers, 70 microm Carbowax divinylbenzene (CW/DVB) and 65 microm polydimethylsiloxane divinylbenzene (PDMS/DVB), were selected for the analysis of several target analytes (phenols, phosphates, phthalates, polycyclic aromatic hydrocarbons, and chlorinated pesticides) identified by the USGS in surface waters. Detection limits for standards ranged from 0.1 to 1 ng/mL for the CW/ DVB fiber and 0.1 to 2 ng/mL for the PDMS/DVB fiber for 20 of the analytes. The remaining analytes were not extracted because their polarity precluded their partition to the solid phase of the SPMEfiber. Groundwater and treated water samples collected from wells in northern New Jersey were then sampled for the USGS analytes by the SPME method as well as a modified version of EPA 525.5 using C-18 bonded solid phase extraction columns. Nine of the USGS analytes-bisphenol A, bis(2-ethylhexyl) phthalate, butylated hydroxytoluene, butlyated hydroxyanisole, diethyltoulamide, diethyl phthalate, bis(2-ethylhexyl) adipate, 1,4-dichlorobenzene, and triphenyl phosphate-were detected in groundwater samples using the CW/ DVB fiber.

Abstract  The transplacental passage of monomethylphtalate (mMP) and mono (2-ethylhexyl) phthalate (mEHP) was studied using an ex vivo placental perfusion model with simultaneous perfusion of fetal and maternal circulation in a single cotyledon. Umbilical cord blood and placental tissue collected both before and after perfusion were also analyzed. Placentas were obtained immediately after elective cesarean section and dually perfused in a recirculation system. mMP or mEHP was added to maternal perfusion medium to obtain concentrations at 10 and 25 microg/L, respectively. The placental transfer was followed analyzing samples from fetal and maternal perfusion media by liquid chromatography-mass spectrometry-mass spectrometry (LC-MS-MS). Four perfusions with mMP indicated a slow transplacental transfer, with a feto-maternal ratio (FM ratio) of 0.30 +/- 0.03 after 150 min of perfusion. Four perfusions with mEHP indicated a very slow or nonexisting placental transfer. mEHP was only detected in fetal perfusion media from two perfusions, giving rise to FM ratios of 0.088 and 0.20 after 150 min of perfusion. Detectable levels of mMP, mEHP, monoethylphthalate (mEP), and monobutylphthalate were found in tissue. Higher tissue levels of mMP after perfusions with mMP compared to perfusions with mEHP suggest an accumulation of mMP during perfusion. No tendency for accumulation of mEHP was observed during perfusions with mEHP compared to perfusions with mMP. Detectable levels of mEHP and mEP were found in umbilical cord plasma samples. mMP and possibly other short-chained phthalate monoesters in maternal blood can cross the placenta by slow transfer, whereas the results indicate no placental transfer of mEHP. Further studies are recommended.

Abstract  The method for simultaneous determination of four phthalates, namely dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP) and di (2-ethylhexyl) phthalate (DEHP) in plastic food-packaging bags by thin layer chromatography (TLC) was developed. The plastic food-packaging bags were extracted with ethanol by ultrasonication, then the mixture was filtrated through membrane (0.45 microm). The mixture of ethyl acetate-anhydrous ether-isooctane (1 : 4 : 15, v/v) was used as developing agent on the TLC silica gel plate for development. The filtered liquid was spotted on the TLC plate dealt by acetone, and detected with scanning wavelength of 275 nm and reference wavelength of 340 nm. The qualitative analysis of the phthalates was performed using the R(f) values of the chromatogram. The quantitative analysis was performed with external standard method. Good linearities were obtained for DMP, DEP, DBP and DEHP. The detection limits were 2.1 ng for DMP, 2.4 ng for DEP, 3.4 ng for DBP and 4.0 ng for DEHP. The relative standard deviations (RSDs) of the four phthalates were 2.8% - 3.5%. The recoveries of the four phthalate standards in real sample were 78.58% - 111.04%. The method presented has the advantages of high precision, high sensitivity, small sample size, and simple pretreatment . The method was used to detect the four phthalates in the food-packaging bags. The contents in real samples were close to the results by gas chromatography.

Abstract  Phthalates are suspected to disrupt the endocrine system, especially through estrogenic effects. In the present study, we investigated the effects of various phthalates and compared them with those of estrogenic compounds that disrupt the female reproductive system. To assess the effects of these phthalates, alteration of the Calbindin-D9k (CaBP-9k) gene was measured as a biomarker because rat CaBP-9k gene carries an estrogen response element (ERE) which is involved in estrogen responsiveness of the gene during the estrous cycle. In this study, phthalates were tested for estrogenic properties in in vitro and in vivo models. First, the E-Screen assay was used to measure the proliferation of MCF-7 cells, a human breast cancer cell line. Treatments with 17beta-estradiol (E2; 9-fold) and 17alpha-estradiol (EE; 9-fold) induced MCF-7 cell proliferation at concentrations of 10(-9) M. Phthalates induced an increase in MCF-7 proliferation at concentration of 10(-6) M up to 10(-4) M. Nbutyl benzyl phthalate (BBP; 6-fold vs. vehicle), dicyclohexyl phthalate (DCHP; 8-fold), 2-ethylhexyl phthalate (DEHP; 6-fold) and di-n-butyl phthalate (DBP; 7-fold) at the concentration of 10(-4) M induced in an increase in MCF-7 proliferation after 6 d of treatment compared to vehicle. However, significant increase in MCF-7 proliferation was induced by diethyl phthalate (DEP). Second, we investigated the expression of CaBP-9k in the uterus of immature rats after oral treatment with BBP, DCHP, DEHP, DBP or DBP (600 mg/kg per day) in this in vivo model, because the immature rat model is highly sensitive to exposure to estrogenic chemicals. None of the phthalates induced the expression of CaBP-9k mRNA and its protein in the neonatal uterus as analysed by Northern and Western blot analyses, respectively. Although phthalates induced an increase in MCF-7 cell proliferation by an estrogenic effect, they could not induce CaBP-9k expression in the in vivo system, suggesting that the assays of estrogenic effects of various phthalates conducted in vitro and in vivo expression of CaBP-9k may produce conflicting results.

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.

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.

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.

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.

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.

Abstract  Due to its biodegradability and renewability, a great interest has been devoted to investigating cellulose acetate in order to expand its potential applications. In addition, secondary cellulose acetate (CDA) could also be considered as a model system for strongly polar polymer system. The dynamical behavior of CDA is supposed to be governed by H-bonding and dipolar interaction network. Due to their high glass transition temperature, cellulose acetate-based systems are processed when blended with plasticizers. It is thus of utmost importance to study the miscibility and plasticizing effects of various molecules. We prepared CDA films via solvent casting method with diethyl phthalate as the plasticizer. Miscibility diagrams were established by calorimetry and thermo-mechanical (DMTA) experiments. Dynamical properties were analyzed by DMTA and broadband dielectric spectroscopy. We could identify the α-relaxation of these CDA-plasticizer systems in the frequency range from 0.06 Hz to 10(6)Hz, which allowed for describing the dynamics in the so-called Williams-Landel-Ferry/Vogel-Fulcher-Tammann regime.

Abstract  Phthalate esters have been known as potent endocrine disruptors and carcinogens; and their removal from water have been of considerable concern recently. In the present study, γ-cyclodextrin polyurethane polymer (GPP), γ-cyclodextrin/starch polyurethane copolymer (GSP), and starch polyurethane polymer (SPP) have been synthesized and characterized. Their adsorption efficiencies for the removal of dimethyl phthalate (DMP) and diethyl phthalate (DEP) from aqueous solutions were investigated. The characterization results showed the success of the synthesis. The isotherms were L-type, and both the Langmuir and Freundlich adsorption isotherm gave good fittings to the adsorption data. Adsorption mechanisms suggested that these adsorbents spontaneously adsorb phthalate molecules driven mainly by enthalpy change, and the adsorption process was attributed to multiple adsorbent-adsorbate interactions such as hydrogen bonding, π-π stacking, and pore filling. The results showed that starch and γ-cyclodextrin polyurethane polymer adsorbents have excellent potential as adsorbent materials for the removal of phthalates from the contaminated water.

Abstract  Phthalate esters are a group of plasticizers, which have been widely detected in China's agricultural and industrial soils. In this study, batch adsorption experiments were conducted to investigate the environmental effects on the adsorption of diethyl phthalate ester (DEP) to clay minerals. The results showed that DEP adsorption isotherms were well fitted with the Freundlich model; the interlayer spacing of K(+) saturated montmorillonite (K-mont) was the most important adsorption area for DEP, and di-n-butyl ester (DnBP) was limited to intercalate into the interlayer of K-mont due to the bigger molecular size; there was no significant effect of pH and ionic strength on DEP adsorption to K-mont/Ca-mont, but to Na-mont clay. The adsorption to kaolinite was very limited. Data of X-ray diffraction and FTIR spectra further proved that DEP molecules could intercalate into K-/Ca-mont interlayer, and might interact with clay through H-bonding between carbonyl groups and clay adsorbed water. Coated humic acid on clay surface would enhance DEP adsorption at low concentration, but not at high concentration (eg. Ce>0.26 mM). The calculated adsorption enthalpy (ΔHobs) and adsorption isotherms at varied temperatures showed that DEP could be adsorbed easier as more adsorbed. This study implied that clay type, compound structure, exchangeable cation, soil organic matter and temperature played important roles in phthalate ester's transport in soil.

Abstract  Oxidative degradation of organic pollutants and its mechanism were investigated in aqueous solution using zero valent copper (ZVC) under aerobic atmosphere condition. Diethyl phthalate (DEP) was completely oxidized after 120min reaction by ZVC at initial pH 2.5 open to the air. DEP degradation followed the pseudo-first-order kinetics after the lag period, and the degradation rate of DEP increased gradually with the increase of ZVC dosage, and the decrease of initial pH from 5.8 to 2.0. ZVC required a shorter induction time and exhibited persistent oxidation capacity compared to that of zero valent iron and zero valent aluminium. The mechanism investigation showed that remarkable amount of Cu(+)/Cu(2+) and H2O2 were formed in ZVC acidic system, which was due to the corrosive dissolution of ZVC and the concurrent reduction of oxygen. The addition of tert-butanol completely inhibited the degradation of DEP and the addition of Fe(2+) greatly enhanced the degradation rate, which demonstrated that hydroxyl radical was mainly responsible for the degradation of DEP in ZVC acidic system under aerobic atmosphere condition, and the formation of hydroxyl radical was attributed to the Fenton-like reaction of in situ formed Cu(+) with H2O2.

Abstract  ZIF-8 (zinc-methylimidazolate framework-8), one of the zeolitic imidazolate frameworks (ZIFs), has been used for the removal of phthalic acid (H2-PA) and diethyl phthalate (DEP) from aqueous solutions via adsorption. The adsorption capacity of the ZIF-8 for H2-PA was much higher than that of a commercial activated carbon or other typical metal-organic frameworks (MOFs). Because the surface area and pore volume of the adsorbents showed no favorable effect on the adsorption of H2-PA, the remarkable adsorption with ZIF-8 suggests a specific favorable interaction (electrostatic interaction) between the positively charged surface of ZIF-8 and the negatively charged PA anions. In addition, acid-base interactions also have a favorable contribution in the adsorption of H2-PA, based on the adsorptive performances of pristine and amino-functionalized MOFs and adsorption over ZIF-8 at acidic condition (pH=3.5). The reusability of ZIF-8 was also demonstrated after simple washing with methanol. On the other hand, ZIF-8 was not effective in adsorbing DEP probably because of little charge of DEP in a water solution.

Abstract  Photochemical degradation of typical phthalate esters, as, e. g. dimethyl phthalate (DMP), in water by the UV/H2O2 process was investigated. The degradation rate of DMP was affected by several reaction factors, including initial DMP concentration, H2O2 concentration, UV light intensity, and coexisting cations and anions. The DMP degradation rate decreased with increasing initial DMP concentration. Carbonate ions significantly reduced the reaction rate by 70.2%, while the degradation rate was improved ten- fold in the presence of ferric ions. The initial reaction mechanism and possible degradation products were investigated using density functional theory (DFT), including B3LYP and M062X hybrid functional. The addition of OH radicals (OH center dot) to the C4 position of the DMP ring is energetically favored for the initial reaction of DMP with OH center dot. Dimethyl 4- hydroxyphthalate (DMP-4OH) is one of the initial degradation intermediates. A possible reaction mechanism was also proposed based on GC/MS analysis and quantum chemical calculations. The formation of DMP-4OH has been explained by quantum chemical calculations, which indicates the advantage and promising role of this method in the degradation mechanism analysis.