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.

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.

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.

Abstract  Phthalate esters with short alkyl chains, such as di-ethyl (DEP), di-n-propyl (DPP), and di-butyl phthalate (DBP), have adjuvant effects on an FITC-induced contact hypersensitivity mouse model. The adjuvant effects of DPP and DBP are associated with enhanced trafficking of FITC-presenting CD11b(+) dendritic cells (DC). DEP has relatively weak activity as to FITC-positive cell migration. Here we demonstrated that DBP and DPP also increased the number of FITC-positive CD8alpha(+) DC in draining lymph nodes. We also found enhanced production of interleukin-4 in draining lymph nodes after FITC sensitization with DEP, DPP, or DBP, suggesting an additional adjuvant mechanism of phthalate esters.

Abstract  This study was undertaken to observe the type of interaction that exists between polychlorinated biphenyls (Clophen A60) and diethyl phthalate (DEP) on the adrenal and thyroid glands of male and female Wistar rats. Animals were divided into four groups of six animals each, group I male and female rats were fed on a normal diet and water ad libitum. Groups II, III and IV male and female rats were given Clophen A60, DEP, or mixture of Clophen A60 and DEP, respectively, each dissolved in corn oil mixed with the diet at 50mg/kg of the diet/day. One hundred days after treatment, females were mated with males for 10 days. Exposure to the pollutants was continued throughout mating, gestation (21 days) until termination at weaning (21 days), which was 150 days of total treatment period of the parental generation. When the F1-generation pups (six males and six females of each group) were 75-100g in weight, they were treated in a similar manner to the parental generation, again for a period of 150 days, with the dose reduced to 25mg/kg of the diet/day in all treated groups. After 150 days of treatment, animals were sacrificed and histology of the adrenal and thyroid glands was asessed. An antagonistic interactive effect of treatment was seen in male parental and F1-generation rats, while an inhibitory type of interactive effect was observed in female rats. In the zona fasciculata region of the adrenal cortex of treated rats of both generations, vacuolations and degeneration were seen in samples from male animals and intracellular vacuolations in samples from females. A synergistic interactive toxic effect to the thyroid gland was observed in treated parental generation male rats, and mild changes in F1-generation-treated male rats, showing follicular shrinkage, loss of thyroglobulin and fibrosis of the interfollicular epithelium. In females, an antagonistic effect to the thyroid gland was observed in both parental and F1-generation-treated rats, showing similar effects as observed in males. From this study, we can conclude that combined administration of Clophen A60 and DEP shows an enhanced toxic effect on adrenal glands of F1-generation male and female rats, but the effect is much more marked in the thyroid gland of F1-generation male rats, and seen to a lesser extent in F1-generation female rats.

Abstract  A method has been developed for the separation and determination of dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DnOP) by micellar electrokinetic chromatography (MEKC). The baseline separation of phthalates was achieved by using a buffer of 100 mM sodium cholate, 50 mM borate and 15% methanol (pH 8.5). The optimized MEKC method was used to quantify the concentrations of phthalates in 11 soil samples from different regions of China. The contents of DEP, DBP and DEHP in soils were ranged 0-0.42, 0-1.43, and 0.24-2.35 mg/kg, respectively, and no DMP and DnOP was detected. The limits of detection for DMP, DEP, DBP, DEHP, and DnOP were found to be 0.050, 0.051, 0.052, 0.054, and 0.063 mg/kg, respectively. The results obtained by the MEKC method were compared with those obtained by gas chromatography with flame ionization detector (GC-FID), and a good agreement was achieved.

Abstract  A previous in vitro study has indicated that four phthalate esters (PAEs) could damage hemocytes and decreases the cellular immunity of prawns [Sung, H.H., Kao, W.Y., Su, Y.J., 2003. Effects and toxicity of phthalate esters to hemocytes of giant freshwater prawn, Macrobranchium rosenbergii. Aquat. Toxicol. 64, 25-37]. The aim of this study was to investigate the in vivo effect of four PAEs, diethyl phthalate (DEP), dihexyl phthalate (DHP), dipropyl phthalate (DPrP) and diphenyl phthalate (DPP) on the defense system of the giant freshwater prawn, M. rosenbergii. PAE dissolved in corn oil was continuously fed to prawns for 8 days and five immune parameters (total hemocyte count, THC; ratio of granulocytes to hyalinocytes, G/H; intrahemocytic total phenoloxidase activity, PO(T); intracellular superoxide anion (O2-) production; transglutaminase (TGase) activity) were separately detected on days 1, 4 and 8. In addition, mortality was determined on days 4 and 8 after challenging the prawns with Lactobacillus garvieae. In comparison with untreated prawns, the results showed that DHP demonstrated the lowest toxicity in that it only influenced the PO activity and O2- production before 4 days after treatment and caused 6.6% mortality on day 8. DEP decreased G/H, PO(T) and TGase activity on day 1 and reduced THC, G/H and PO(T) and caused 16.6% mortality on day 4; however, on day 8, it increased O2- production and caused no mortality. In the DPrP-treated group, a reduction of all the immune reactions apart from TGase activity and 22.2% mortality were detected on day 4. As for the effect of DPP, results showed that it decreased all the immune parameters apart from THC on days 1 and 4, but caused no mortality on day 4; but on day 8, an increase of O2- production and 17.7% mortality were detected. These results indicated that the immune reactions of prawns were variable due to the different toxic effects of PAEs. In addition, it was found that, on day 8 after treatment, the three PAEs, DHP, DPrP and DPP increased O2- production and did not influence the other four reactions, but mortality was detected in these groups. These results suggest that other physiological responses may also be affected to increase the susceptibility of prawns to pathogens.

Abstract  A routine method which is simple, quick and precise has been set up and validated for phthalate analysis in environmental samples (tomato plants and sewage sludges). Six phthalates have been studied simultaneously: dimethylphthalate, diethylphthalate, di-n-butylphthalate, n-butylbenzylphthalate, di-2-ethyl-hexyl phthalate (DEHP) and di-n-octylphthalate. Optimization of sample, solvent extraction uses a Soxtec apparatus and extract purification with an a solid-phase extraction cartridge allows between 90 and 110% recovery of phthalates. Precise, sensitive and selective identification and quantifying of analytes is by GC-MS in the single ion monitoring mode. This protocol allows analytes with concentrations as low as 10 microg/kg dry matter (DM) to be determined from small (1-2 g DM) samples. This analytical method has been applied to the phthalate transfer study for agricultural recycling of sludges, where phthalate bioavailability has been studied in aquiculture using two types of experiments. Tomatoes have been grown in containers where the trace organics have been directly introduced as pure substances, and in a second experiment under the same growth conditions, sewage sludge has replaced the pure substances. Transfer of these trace organics has been followed into the various parts of the tomato plant and in general only the DEHP is worthy of note although its percentage transfer remains very low even in an experiment designed to maximize this.

Abstract  The sonochemical degradation of aqueous solutions containing low concentrations of six phthalate esters at an ultrasonic frequency of 80 kHz has been investigated. Ultrasonic treatment was found capable of removing the four higher molecular mass phthalates (di-n-butyl phthalate, butylbenzyl phthalate, di-(2-ethylhexyl) phthalate and di-n-octyl phthalate) within 30-60 min of irradiation. The rest (dimethyl phthalate and diethyl phthalate) were more recalcitrant and nearly complete removal could be achieved only after prolonged irradiation times. The relative reactivity of phthalates was explained in terms of their hydrophobicity. Experiments were carried out at an overall initial phthalate concentration of 240 microg l(-1), values of electric power of 75 and 150 W, temperatures of 21 and 50 degrees C and in the presence of NaCl to study the effect of various operating conditions on degradation. Solid-phase microextraction (SPME) coupled with GC-MS proved to be a powerful analytical tool to monitor the sonochemical degradation of phthalate esters at low microg l(-1) concentration levels, minimising the risk of secondary contamination during sample preparation, a major parameter to consider during phthalates analysis. The advantages as well as disadvantages of using SPME are also highlighted.

Abstract  Researchers have recently reported on the nongenomic action of estrogen via membrane receptors and ion channels, especially nicotinic acetylcholine receptors (nAChR). We studied the nongenomic effects of eight phthalates (an endocrine disrupter that expresses estrogen-like activity through estrogen receptors): di-n-ethyl (DEP), di-n-propyl (DPrP), di-n-butyl (DBP), benzyl-n-butyl (BBP), di-n-pentyl (DPP), di-n-hexyl (DHP), dicyclohexyl (DCHP), and di-(2-ethylhexyl) (DEHP). Specifically, we looked at their individual effects on cytosolic free calcium concentration rise induced by three nAChR agonists: carbachol, 1,1-dimethyl-4-phenyl-piperazinium iodide, and epibatidine. Results show that all of the tested phthalates suppressed nAChR-coupled Ca(2+) response. Strongest to weakest potencies were observed as DPP --> BBP --> DBP --> DCHP --> DHP --> DPrP --> DEHP --> DEP. DPP, DBP, and BBP were 10 times more potent than estradiol. We suggest that phthalate potency was associated with its chemical structure, since (a) the most effective phthalates had dialkyl group carbon numbers of C4 or C5, with shorter or longer numbers resulting in decreased potency, and (b) the presence of an alkyl ring or phenoic structure resulted in increasing potency. Because of the similarity between this relationship and estrogen receptor-binding potency, we suggest that the inhibitory effect of phthalates on nAChR-coupled Ca(2+) response is an indication of their nongenomic estrogen-like activity.

Abstract  The present work investigates release mechanisms of theophylline pellets coated with an aqueous ethyl cellulose (EC) dispersion containing plasticizers and hydroxypropyl methylcellulose (HPMC) as a water soluble pore former. Three different drug release mechanisms from coated pellets can be determined as a function of the water solubility of the plasticizers and the ionic strength of the release medium. Coated pellets with the addition of more hydrophilic plasticizers such as triethyl citrate (TEC) or diethyl phthalate (DEP) show an approximate zero-order-release rate. In contrast, two-phase release profiles can be observed from pellets coated with dispersions containing hardly soluble plasticizers such as dibutyl phthalate (DBP) or dibutyl sebacate (DBS). Only in a release medium of high ionic strength the water soluble pore former will remain in the coating. Thus the drug diffuses through a hydrated swollen membrane containing EC, HPMC and insoluble plasticizer. The release mechanisms depend on the glass transition temperature of the ethyl cellulose and therefore on the migration of the plasticizers and the pore former. This was shown by investigation of the migration of the additives and the influence of the temperature of the release medium on the release. Additionally, the study investigates the effect of curing and storage conditions of coated pellets on the drug release rate.

Abstract  Laboratory and field trials of dimethyl phthalate (DMP), diethyl phthalate (DEP) and dibutyl phthalate (DBP) were carried out in order to evaluate the substances in detail and comparatively as repellents against blood sucking arthropods and also to determine their toxicity for warm blooded animals. DBP was found to possess comparatively more stable repelling properties against fleas (Xenopsilla cheopis) and ticks (Xodes persulcatus), whereas DMP and DEP showed better properties as repellents in trials in olfactometers for mosquitoes and horse flies. When the drugs were applied on the skin it was found that in hot weather in the Krasnoyarsk region DMP protected against mosquitoes (Aedes gr. communis) for 6 hr 50 min, DEP for 1 hr 20 min and DBP for 40 min, and in cool weather for 7 hr 40 min, 5 hr and 3 hr 50 min, respectively. All 3 substances (DMP, DEP, DBP) have a relatively low general toxicity but a strong irritant effect when applied to the conjunctival mucosa. The drugs produced no irritation of the skin after numerous applications in man.

Abstract  On the basis of studies of hygienic regulation of diethylphthalate (DEP), di-n-hexylphthalate (DHP) and dialkylphthalate-810 (DAP-810) in the water medium) it has been found out that the compounds are highly persistent in the water medium, are of low toxicity (LD50 from 10.3 up to 33 g/kg and more for white rats), belong to the third and fourth (DHP and DAP-810) classes of danger. The threshold concentrations of DEP, DHP, DAP-810 according to the organoleptic water properties and sanitary regimen of water reservoirs were determined on the level of 1, 0.46, 0.3 and 0.1, 1, and 1 mg/l respectively. DEP has moderately expressed cumulative properties while in DHP and DAP-810 they are clearly expressed. No specific effect was observed in the compounds. MACs for DEP, DHP and DAP-810 in the water medium are recommended on the level of 0.1, 0.5 and 0.3 mg/l according to the general toxic and organoleptic indices of harmfulness.

Abstract  Recent experimental studies in Japan on the evaluation of potential health hazards from phthalate esters used in manufacturing poly (vinyl chloride) as well as several plastics for medical devices and for food containers and packages were introduced. Development of pulmonary granuloma formation after intravenous injection of diethylhexyl phthalate was assumed to be dependent on the particle size of the phthalate in vehicle used. Dietary administration of large amount of diethylhexyl phthalate and dibutyl phthalate produced renal cysts in mothers and in descendants in reproduction studies in mice. Cytotoxicity and mutagenicity of the phthalates and several plastics and resins were also examined by in vivo and in vitro studies. Hematological parameters examined in rabbits after repeated intravenous injection of diethylhexyl phthalate and after implantation of plastics in aorta for 3--6 months did not show any significant change. A slow decrease of radioactivity was observed in adipose tissue of rats following oral administration of 14C-labeled diethylhexyl phthalate. tthe administrative action on phthalates by the Japanese Ministry of Health and Welfare is briefly reviewed.

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.

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.

Abstract  These studies compared the reproductive toxicity of four phthalates by a continuous breeding protocol. Mice were given diets with diethyl phthalate (DEP) (0.0, 0.25, 1.25, or 2.5%), di-n-butyl phthalate (DBP) (0.0, 0.03, 0.3, or 1.0%), di-n-hexyl phthalate (DHP) (0.0, 0.3, 0.6, or 1.2%), or di(2-ethylhexyl) phthalate (DEHP) (0.0, 0.01, or 0.3%). Both male and female CD-1 mice were dosed for 7 days prior to and during a 98-day cohabitation period. Reproductive function was evaluated during the cohabitation period by measuring the numbers of litters per pair and of live pups per litter, pup weight, and offspring survival. There was no apparent effect on reproductive function in the animals exposed to DEP, despite significant effects on body weight gain and liver weight. DBP exposure resulted in a reduction in the numbers of litters per pair and of live pups per litter and in the proportion of pups born alive at the 1.0% amount, but not at lower dose levels. A crossover mating trial demonstrated that female mice, but not males, were affected by DBP, as shown by significant decreases in the percentage of fertile pairs, the number of live pups per litter, the proportion of pups born alive, and live pup weight. DHP in the diet resulted in dose-related adverse effects on the numbers of litters per pair and of live pups per litter and proportion of pups born alive at 0.3, 0.6, and 1.2% DHP in the diet. A crossover mating study demonstrated that both sexes were affected. DEHP (at 0.1 and 0.3%) caused dose-dependent decreases in fertility and in the number and the proportion of pups born alive. A crossover mating trial showed that both sexes were affected by exposure to DEHP. These data demonstrate the ability of the continuous breeding protocol to discriminate the qualitative and quantitative reproductive effects of the more and less active congeners as well as the large differences in reproductive toxicity attributable to subtle changes in the alkyl substitution of phthalate esters.

Abstract  It has been speculated that maternal phthalate exposure may affect reproductive development in human newborns. However, the mechanism awaits further investigation. The aim is to evaluate the association between maternal phthalate exposure and cord sex steroid hormones in pregnant women and their newborns from the general population. A total of 155 maternal and infant pair were recruited and analyzed. Levels of urinary phthalate metabolites and sex steroid hormones were determined using liquid chromatography/electrospray tandem mass spectrometry (LC-ESI-MS/MS) and radioimmunoassay (RIA), respectively. No significant correlation was found between each steroid hormones and phthalate metabolites for male newborns, except MMP was marginally significantly correlated with E(2). After adjusting for maternal age, estradiol (E(2)) levels in cord serum from male newborns were not correlated with maternal urinary phthalate metabolites. In female newborns, the maternal urinary levels of mono-(2-ethylhexyl) phthalate (MEHP) and mono-(2-ethyl-5-hydroxyhexyl) phthalate (5OH-MEHP) were negatively correlated with the free testosterone (fT) and fT/E(2) levels in cord serum with Pearson correlation coefficients ranging between -0.24 and -0.29 (p<0.05). Additionally, after gestational age was adjusted, the maternal urinary level of DEHP was negatively correlated with the free testosterone (fT) and fT/E(2) levels in cord serum. We suggest that maternal exposure to phthalates may affect sex steroid hormones status in fetal and newborn stage.

Abstract  Method was developed for the simultaneous determination of 17 classified and suspected endocrine-disrupting compounds (EDCs). Phenol, 2-nitrophenol, 4-nitrophenol, 4-dinitrophenol, 4-chlorophenol, 2,4-dimethylphenol, 2: methyl 4,6-dinitro-phenol, 2-chlorophenol, 2,4-dichlorophenol, 4-chloro-3-methylphenol, pentachlorophenol, dimethyl phthalate, diethyl phthalate, benzylbutyl phthalate, dioctyl phthalate, diethylhexylphthalate and dibutyl phthalate. Qualitative and quantitative analyses were performed by gas chromatography mass spectrometry (GC-MS) using)B-5MS column. These compounds were evaluated using solid-phase extraction for raw and treated wastewater from a municipal treatment plant. Phenols were derivatized with N-(t-butyldimethylsilyl)-N-methyl-trifluoroacetamide (MTBSTFA) to form their respective t-butyldimethylsilyl derivatives. The extraction recovery range from 73.21 to 01.32% for 2,4,6-TCP and DEHP respectively. The occurrence pattern of phenol is in the order of PCP > 2CP > POH > 2NP > 2M- 4,6 DNP (old plant) and PCP > 2M- 4,6 DNP > POH 2CP 2NP for old and new plants respectively. Phthalates ranked as DEP > DBP > DEHP with corresponding values of 2473 991; 2000 : 236; and 192 = 127 mu gL(-1) in the new plant. The average percent removal of analytes range from 54.77 to 89.34% in the two plants investigated.

Abstract  The mutagenic potential of dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), and di-2-ethylhexyl phthalate (DEPH), as well as metabolites of DEHP--i.e., mono-2-ethylhexyl phthalate (MEHP), 2-ethylhexanol (2-EH), and phthalic acid (PA)--were tested in Salmonella typhimurium cultures using the Ames test procedure. The compounds were tested on strains TA98, TA100, TA1535, TA1537, TA1538, and TA2637 for base-pair substitution or frameshift-type mutations. Spot tests yielded negative responses for all compounds with the strains tested. Each compound was tested for a dose-effect relationship in the TA98, TA100, TA1535, and TA1538 systems. DEP and DBP exhibited a mildly positive response in both TA100 and TA1535 cultures, and DMP showed a similar response in TA1535. Normalization of the data for cytotoxicity of DMP suggests TA100 has a mildly positive effect. The higher doses of these compounds exhibited some cytotoxic effects. The mutagenic effects were apparently abolished by the addition of S9 fraction in TA100 and TA1535 cultures, while no effect, other than cytotoxicity, was observed in the TA98 and TA1538 systems. DEHP, MEHP, 2-EH, and PA exhibited no mutagenicity in any of the strains of Salmonella typhimurium tested, with or without S9 metabolic activation. MEHP and 2-EH, however, exhibited a moderate cytotoxic effect in most cultures

Abstract  Tests were performed with the freshwater invertebrates Hyalella azteca, Chironomus tentans, and Lumbriculus variegatus to determine the acute toxicity of six phthalate esters, including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP), di-n-hexyl phthalate (DHP), and di-2-ethylhexyl phthalate (DEHP). It was possible to derive 10-d LC50 (lethal concentration for 50% of the population) values only for the four lower molecular weight esters (DMP, DEP, DBP, and BBP), for which toxicity increased with increasing octanol-water partition coefficient (Kow) and decreasing water solubility. The LC50 values for DMP, DEP, DBP, and BBP were 28.1, 4.21, 0.63, and 0.46 mg/L for H. azteca; 68.2, 31.0, 2.64, and > 1.76 mg/L for C. tentans; and 246, 102, 2.48, and 1.23 mg/L for L. variegatus, respectively. No significant survival reductions were observed when the three species were exposed to either DHP or DEHP at concentrations approximating their water solubilities

Abstract  Phthalic acid esters (PAE) are commonly found in the sludge generated in the wastewater treatment plants. Anaerobic digestion followed by land application is a common treatment and disposal practice of sludge. To date, many studies exist on the anaerobic biodegradation rates of PAE, especially of the easily biodegradable ones, whereas the higher molecular weight PAE have reported to be non-biodegradable under methanogenic conditions. Furthermore, there is no information on the effect of the PAE on the performance of the anaerobic digesters treating sludge. In this study, the anaerobic biodegradation of di-n-butyl phthalate (DBP), di-ethyl phthalate (DEP) and di-ethylhexyl phthalate (DEHP) was investigated and their relative rates of anaerobic degradation were calculated. Also, the biological removal of PAE during the anaerobic digestion of sludge in bench-scale digesters was investigated using DBP and DEHP as model compounds of one biodegradable and one recalcitrant PAE respectively. The degradation of all the PAE tested in this study (DEP, DBP and DEHP) is adequately described by first-order kinetics. Batch and continuous experiments showed that DEP and DBP present in sludge are rapidly degraded under mesophilic anaerobic conditions (a first-order kinetic constant of 8.04 x 10(-2) and 13.69 x 10(-2)-4.35 day(-1) respectively) while DEHP is degraded at a rate between one to two orders of magnitude lower (0.35 x 10(-2)-3.59 x 10(-2) day(-1)). It is of high significance that experiments with anaerobic sludge of different origin (US and Europe) showed that degradation of DEHP occurs under methanogenic conditions. Accumulation of high levels of DEHP (more than 60 mg/l) in the anaerobic digester has a negative effect on DBP and DEHP removal rates as well as on the biogas production

Abstract  Of the many compounds that leach from respiratory therapy tubing into air passing through it, we selected five compounds to analyze. The five compounds are known to be potentially carcinogenic, toxic or known to induce estrogenic activity. Parts-per-million and parts-per-billion concentrations of these species were found in the air passing through the tubing: the plasticizers di-(2-ethylhexyl) phthalate (DEHP) and di-ethyl phthalate (DEP), the antioxidants butylated hydroxy toluene (BHT) and p-nonylphenol (p-NP), and the contaminant (from commercial preparation of DEHP) 2-ethylhexanol (2-EH). These levels are high enough to cause some concern about exposure for patients who use oxygen on a long-term basis, those sensitive or allergic to these species, or those with asthma. A method was developed for analysis of solid tubing samples, showing great variability in concentrations of small, volatile molecules from sample to sample. A method was also developed for pre-concentration of small molecules onto Tenax adsorbants from air passing through the tubing. Both solid samples and adsorbant loaded with analyte were analyzed by direct dynamic thermal desorption gas chromatography mass spectrometry (GCMS). This study does not imply that adverse reactions by patients to chemical compounds leaching from respiratory medical tubing will occur but that further investigation is warranted

Abstract  For screening chemicals possessing endocrine disrupting potencies, the uterotrophic assay has been placed in a higher level in the OECD testing framework than the ER binding assay to detect ER-mediated activities. However, there are no studies that can demonstrate a clear relationship between these assays. In order to clarify the relationship between the in vitro ER binding and in vivo uterotrophic assays and to determine meaningful binding potency from the ER binding assay, we compared the results from these assays for 65 chemicals spanning a variety of chemicals classes. Under the quantitative comparison between logRBAs (relative binding affinities) and logLEDs (lowest effective doses), the log RBA was well correlated with both logLEDs of estrogenic and anti-estrogenic compounds at r(2)=0.67 (n=28) and 0.79 (n=23), respectively. The RBA of 0.00233% was found to be the lowest ER binding potency to elicit estrogenic or anti-estrogenic activities in the uterotrophic assay, accordingly this value is considered as the detection limit of estrogenic or anti-estrogenic activities in the uterotrophic assay. The usage of this value as cutoff provided the best concordance rate (82%). These findings are useful in a tiered approach for identifying chemicals that have potential to induce ER-mediated effects in vivo.