Abstract  The human exposure estimates for dibutyl (DBP) and bis(2-ethylhexyl) phthalate (DEHP) made by two models EUSES and ACC-Human, and by an estimation approach which utilized measured concentrations in exposure media, were compared. The approach which utilized the latest monitoring data for important exposure media, yielded median daily intakes for adult humans for DBP and DEHP of 2.7 and 5.6 microg/kg body weight per day, respectively, which were in the same range as previous estimates based on back-calculation from urinary metabolites. EUSES estimated average daily intakes of DBP and DEHP for humans that were between 8 and 13 times lower. ACC-Human does not estimate average daily intakes, but ACC-Human-estimated human milk concentrations/fugacities were more than a thousand times lower than measured concentrations/fugacities in human milk. It was concluded that the two models underestimate human exposure to phthalate esters because they consider only a few key pathways that are known to be important for other, more persistent, hydrophobic organic compounds. Further, it was shown that there are differences between the two models on the methodology for estimating concentrations in exposure media such as vegetation, milk, beef and fish. ACC-Human uses a mechanistic approach for estimating transfer through aquatic and terrestrial food chains that are known to be important for human exposure to persistent, hydrophobic organics and can, unlike EUSES, account for food chain metabolism. It proved difficult, however, to obtain organism metabolism rates needed as model inputs to ACC-Human. If exposure estimates of phthalate esters are needed, it is recommended to use an estimation approach based on high quality monitoring data as presented here and/or back-calculate daily intake from concentrations of metabolites in human urine samples from the general population.

Abstract  To explore the possible actions of endocrine disruptors on the autacoid synthesis in the body, we investigated the effects of nonylphenol (NP), bisphenol A (BPA), di-n-butyl phthalate (DBP), benzyl-n-butyl phthalate (BBP), and di-2-ethylhexyl phthalate (DEHP) on the formation of 12-lipoxygenase metabolite, 12-HETE, and cyclooxygenase metabolites, TXB(2) and 12-HHT, from exogenous arachidonic acid (AA) in rabbit platelets. NP (10-50 microM) showed strong inhibition on the formation of cyclooxygenase metabolites (TXB(2), 34-95% inhibition; 12-HHT, 13-78% inhibition) and weaker inhibition on the formation of 12-HETE (0-49% inhibition). BPA, DBP, BBP, DEHP, and 17beta-estradiol (endogenous estrogen) failed to show any effect on the formation of cyclooxygenase and 12-lipoxygenase metabolites at concentrations up to 100 microM. These results suggest that NP inhibits AA metabolism in platelets and that its effects on the cyclooxygenase pathway predominate over those exerted via the 12-lipoxygenase pathway

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  Contamination of the organic fraction of municipal solid waste (OFMSW) with xenobiotic compounds and their fate during anaerobic digestion was investigated. The phthalic acid ester di-(2-ethylhexyl)phthalate (DEHP) was identified as the main contaminant in OFMSW in concentrations more than half of the threshold value for the use as fertilizer on agricultural soil in Denmark. Analysis of DEHP in samples before and after large-scale anaerobic digesters revealed higher concentrations of DEHP per kg dry matter in the effluent than in the influent. The concentration of DEHP and DBP (dibutylphthalate) in OFMSW was monitored in the influent and effluent of anaerobic thermophilic (55 degrees C) and hyper-thermophilic (68 degrees C) laboratory-scale reactor systems. In the thermophilic reactors with a hydraulic retention time (HRT) of 15 days 38-70% of DBP was removed, but no consistent removal of DEHP was observed. However, after treatment of the effluent from the thermophilic reactor in a hyper-thermophilic digester (HRT: 5 days) 34-53% of the DEHP content was removed and the DBP removal was increased to further 62-74%. Removal rates (k(h)) of DEHP and DBP were found to be 0.11-0.32 d(-1) and 0.41-0.79 d(-1), which is much higher than in previous investigations. It can be concluded that the higher removal rates are due to the higher temperature and higher initial concentrations per kg dry matter. These results suggest that the limiting factor for DEHP degradation is the bioavailability, which is enhanced at higher temperature and higher degradation of solid organic matter, to which the highly hydrophobic DEHP is adsorbed. The investigated reactor configuration with a thermophilic and a hyper-thermophilic treatment is, therefore, a good option for combining high rate degradation of organic matter with high biogas yields and efficient reduction of the phthalic acid ester contamination

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.

Abstract  In continuous breeding reproduction studies in which an adverse effect on fertility was detected over an 18-week treatment period, a crossover mating trial was then conducted to determine the affected sex. Results of 25 crossover breeding studies conducted using Swiss (CD-1) mice were compared with results of sperm morphology and vaginal cytology examinations (SMVCEs) conducted at the conclusion of the mating trial. SMVCE endpoints include sperm concentration, motility, and morphology, vaginal cytology, and male reproductive organ weights. In most SMVCE studies multiple endpoints were adversely affected. For male reproductive toxicants, sperm motility was decreased in 89% of the studies, and absolute right epididymis and right testis weights were affected less frequently (80% each). Among studies with no detectable reduction in male breeding performance, 87% exhibited no detectable decrease in epididymis weight. Eighty-two percent had no change in cauda epididymis weight and 80% had no significant change in sperm concentration. An increase in female cycle length was associated (100%) with an effect on breeding due to female dysfunction. Overall accuracy, defined as correct identification of toxicants and nontoxicants, was highest for epididymis weight (84%), followed by cauda epididymis weight and sperm motility (79% each), and sperm concentration (76%). Female cycle length was so variable that the overall accuracy of the parameter in 13 studies was 69%. With the variety of chemicals used in this analysis, the association of abnormal sperm morphology with reproductive outcome was 71%. Control data (mean, 95% confidence interval around the mean, median, and statistical sensitivity) for each male endpoint (parent, and offspring at 10 weeks of age following a single breeding) were summarized from each of the two laboratories that conducted the studies. For several endpoints, statistical power was dependent on the laboratory conducting the studies. In general, the statistical sensitivity was relatively high for reproductive organ weights, although it was less for smaller organs such as the prostate. On the basis of both the biological and statistical analyses, it is recommended that multiple SMVCE endpoints, including sperm measure, be included in screens for reproductive toxicants.

Abstract  A method was established for the simultaneous determination of some phthalic acid esters, namely, dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPrP), dibutyl phthalate (DBP), diamyl phthalate (DAP), dihexyl phthalate (DHP), benzyln-butyl phthalate (BBP), di-(2-ethylhexyl) phthalate (DEHP), dicyclohexyl phthalate (DCHP), di-n-octyl phthalate (DNOP), diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP) in textiles by solid phase extraction (SPE) coupled with gas chromatography (GC). The phthalic acid esters in textiles were extracted by Soxhlet extraction with hexane, the extracts were then cleaned up and enriched by a strong anion exchange (SAX) SPE cartridge. The parameters affecting the purification efficiency of SPE cartridge, such as solvent conditioning, rinsing, and elution, were studied. Conditioning with 5 mL hexane and rinsing with 3 mL isooctane were proved to be the optimal conditions. Of the several solvent ratios (ethylacetate in hexane) used for selective elution of phthalic acid esters from the SAX SPE cartridge, the 15% (v/v) content for ethylacetate in hexane gave the best result. Under the optimized conditions, the recoveries of phthalic acid esters for spiked standards (n=7) were 86.3%-102.7%, and the relative standard deviations (RSDs) were less than 5%. In this method the detection limits for DMP, DEP, DPrP, DBP, DAP, BBP, DCHP, DEHP, DNOP were all below 1 mg/kg, and the detection limits for DINP and DIDP were 1.74 mg/kg and 1.55 mg/kg respectively. This SPE-GC method is sensitive, accurate and suitable for the analysis of phthalate environmental hormones in textiles.

Abstract  The National Toxicology Program (NTP) and the National Institute of Environmental Health Sciences established the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) in June, 1998. The purpose of the Center is to provide timely, unbiased, scientifically sound evaluations of human and experimental evidence for adverse effects on reproduction, including development, caused by agents to which humans may be exposed. The following seven phthalate esters were selected for the initial evaluation by the Center: butyl benzyl phthalate, di(2-ethylhexyl) phthalate, di-isodecyl phthalate, di-isononyl phthalate, di-n-butyl phthalate, di-nhexyl phthalate, and di-n-octyl phthalate. Phthalate esters are used as plasticizers in a wide range of polyvinyl chloride-based consumer products. These chemicals were selected for the initial evaluation by the CERHR based on their high production volume, extent of human exposures, use in children's products, published evidence of reproductive or developmental toxicity, and public concern.

Abstract  The National Toxicology Program (NTP) and the National Institute of Environmental Health Sciences established the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) in June, 1998. The purpose of the Center is to provide timely, unbiased, scientifically sound evaluations of human and experimental evidence for adverse effects on reproduction, including development, caused by agents to which humans may be exposed. The following seven phthalate esters were selected for the initial evaluation by the Center: butyl benzyl phthalate, di(2-ethylhexyl) phthalate, di-isodecyl phthalate, di-isononyl phthalate, di-n-butyl phthalate, di-nhexyl phthalate, and di-n-octyl phthalate. Phthalate esters are used as plasticizers in a wide range of polyvinyl chloride-based consumer products. These chemicals were selected for the initial evaluation by the CERHR based on their high production volume, extent of human exposures, use in children's products, published evidence of reproductive or developmental toxicity, and public concern.

Abstract  The National Toxicology Program (NTP) and the National Institute of Environmental Health Sciences established the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) in June, 1998. The purpose of the Center is to provide timely, unbiased, scientifically sound evaluations of human and experimental evidence for adverse effects on reproduction, including development, caused by agents to which humans may be exposed. The following seven phthalate esters were selected for the initial evaluation by the Center: butyl benzyl phthalate, di(2-ethylhexyl) phthalate, di-isodecyl phthalate, di-isononyl phthalate, di-n-butyl phthalate, di-nhexyl phthalate, and di-n-octyl phthalate. Phthalate esters are used as plasticizers in a wide range of polyvinyl chloride-based consumer products. These chemicals were selected for the initial evaluation by the CERHR based on their high production volume, extent of human exposures, use in children's products, published evidence of reproductive or developmental toxicity, and public concern.

Abstract  The 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) family of proteins regulates the levels of the active 17 beta-hydroxy forms of sex steroids. The expression of 17 beta-HSD type IV is induced by peroxisome proliferator chemicals (PPC) in rat liver. In order to characterize more generally the impact of PPC on 17 beta-HSD expression, we determined (1) if expression of other members of the 17 beta-HSD family was coordinately induced by PPC exposure, (2) the tissues in which 17 beta-HSD was induced by PPC, and (3) whether the induction of 17 beta-HSD by PPC was dependent on the peroxisome proliferator-activated receptor alpha (PPAR alpha), the central mediator of PPC effects in the mouse liver. The mRNA levels of 17 beta-HSD I, II, and III were not altered in the liver, kidney, and testis or uterus of rats treated with PPC. The mRNA or 80 kDa a full-length protein levels of 17 beta-HSD IV were strongly induced in liver and kidney, but not induced in adrenals, brown fat, heart, testis, and uterus of rats treated with diverse PPC. In liver and kidneys from treated rats, additional proteins of 66 kDa, 56 kDa, and 32 kDa were also induced which reacted with the anti-17 beta-HSD IV antibodies and were most likely proteolytic fragments of 17 bega-HSD IV. Treatment of mice which lack a functional form of PPAR alpha with PPC, demonstrated that PPC-inducibility of 17 beta-HSD IV mRNA or the 80 kDa protein was dependent on PPAR alpha expression in liver and kidney. Our results demonstrate that 17 beta-HSD IV is induced by PPC through a PPAR alpha-dependent mechanism and support the hypothesis that exposure to PPC leads to alterations in sex steroid metabolism.

Abstract  Oral administration of di-(2-ethylhexyl) phthalate (I) [117-81-7] and dibutyl phthalate (II) [84-74-2] in the diet for 1-3 months at 5.0 and 0.5 g/kg/day to mice resulted in marked lesions mostly in the liver and kidney. In the higher dose group, the liver showed remarkable vacuolar degeneration and necrosis of single cells, while the kidney showed cysts and degeneration of tubule epithelial cells. In the low dose group, degeneration of liver and kidney parenchyma was obsd. The cytotoxicity of I was greater than that of II.

Abstract  Effects of estrogenic compds. (bisphenol A, alkyl phenols, phthalate esters, and genistein) on T lymphocyte apoptosis were investigated in vitro. The assays were performed in the absence or presence of low concns. of apoptosis-inducing agents etoposide or dexamethasone to detect apoptosis-inducing, -enhancing, and -suppressing activities of the test compds. When T lymphatic Jurkat cells were exposed to 10 ?M bisphenol A for 20 h, apoptosis was not induced, but apoptosis induced by 1 ?M etoposide was significantly enhanced. The 4-n-Nonylphenol (10 ?M) showed an apoptosis-inducing activity significantly. The 4-tert-Octylphenol (10 ?M) exhibited an apoptosis-enhancing activity. In contrast, phthalate esters including di-Bu phthalate and di-2-ethylhexyl phthalate showed neither activity at 10 ?M. Genistein (10 ?M) significantly exhibited apoptosis-inducing and enhancing activities. On the other hand, 17?-estradiol did not show any of these activities at 10 nM, the concn. exerting the estrogenic activity comparable to or much higher than that of 10 ?M of the test compds. Effects of these estrogenic compds. on apoptosis were also investigated using mouse primary thymocytes. Mouse thymocytes similarly exposed to the estrogenic compds. in the absence or the presence of dexamethasone for 6 h were characterized. In agreement with Jurkat cells, apoptosis-inducing or/and -enhancing activities were obsd. for the cells coincubated with bisphenol A, alkyl phenols, and genistein, but not those with di-2-ethylhexyl phthalate or 17?-estradiol. The apoptosis-inducing or/and -enhancing effects of the estrogenic compds. obsd. here appear to be due to their unidentified properties other than estrogenic activity.

Abstract  Di(2-ethylhexyl)phthalate (DEHP) used as a common plasticizer additive in the manuf. of plastics, such as polyvinyl chloride (PVC). This study examd. the effect of DEHP on steroidogenesis or spermatogenesis in the testes of Sprague-Dawley male rats treated orally with 250, 500, 750 mg/kg over a 30-day period. The expression levels of the steroidogenic- or spermatogenic-related genes were analyzed in the testis using a reverse transcription-polymerase chain reaction (RT-PCR) and Western blot anal. High doses of DEHP (500 and 750 mg/kg) significantly decreased the testicular sperm counts and daily sperm prodn. (DSP). In addn., serum testosterone levels were significantly lower in the DEHP treatment groups than in the control. The mRNA levels of SR-B1, StAR, PBR and CYP17 increased in a dose-dependent manner. These increases were significant at 500 and 750 mg/kg. In the other hand, the mRNA levels of CYP19 decreased significantly in testes of rats exposed to DEHP 500 and 750 mg/kg. Dose-dependent decreases in Spag4 and LDHA mRNA in the testis were obsd. after DEHP exposure, while there was a significant decrease in thyroid hormone receptor (TR)?1 protein levels. After DEHP exposure, while there was a significant decrease in thyroid hormone receptor (TR)?1 protein levels. High doses of DEHP significantly increased the expression of peroxisome proliferator-activated receptor (PPAR)-? and retinoid X receptor (RXR)-? protein but markedly decreased the expression of RXR-?. These results suggest that DEHP exposure can later the expression of the spermatogenic- or steroidogenic-related genes resulting in a decrease in sperm prodn. in the testis. This study is expected to be helpful in research examg. the mechanisms for how DEHP reduces the expression pattern of the genes involved steroid hormone synthesis after chronic exposure to DEHP.

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  Toxicologic effects of di-(2-ethylhexyl) phthalate, di-n-butyl phthalate, di-(n-octyl)tin S,S′-bis-(isooctyl mercaptoacetate), dibenzyltin S,S′-bis-(isooctyl mercaptoacetate), as well as their effect on reproduction and fetal development were examined in Wistar rats. In a 3-month toxicity study all the compounds produced a statistically significant increase in the mean liver weight of the animals. Rats fed dietary levels 0.35% of di-(2-ethylhexyl)phthalate and 0.02% of di-(n-octyl)tin S,S′-bis-(isooctyl mercaptoacetate) for periods up to 12 months showed a significant decrease in body weight and an increase in kidney weight; furthermore, di-(2-ethylhexyl) phthalate caused liver enlargement. Red and white blood cell counts, hemoglobin concentration and histopathology of liver, kidneys, and spleen were within normal limits. Reproduction studies showed an increased number of resorptions and decreased fetal body weights. Doses of 0.02 and 0.04 g/kg of di-(n-octyl)tin S,S′-bis-(isooctyl mercaptoacetate) also caused a 17% incidence in fetal deaths. No gross abnormalities were found in the fetuses.

Abstract  In order to study the biochemical changes involved in the testicular damage induced by phthalate ester plasticizers, dibutyl phthalate (DBP), a representative plasticizer, was administered orally to mature male rats for one week. The rats were sequently killed at 1, 7, 14, and 21 days after the final administration of DBP. One testis was examined histologically and the other was subjected to assay for the activities of the testicular enzymes lactate dehydrogenase-X (LDH-X) and ornithine decarboxylase (ODC). On day I, the testes were clearly atrophied. Histologically, the germ cells had almost disappeared in the seminiferous tubules. On day 21, the testicular damage had mostly recovered. Enzyme assay showed that LDH-X activity was depressed severely on day I, but recovered with time. Therefore, its activity showed good correlation with the histological changes in the testis. ODC activity was depressed on day I but elevated on day 14. This indicated that the recovery of ODC activity preceded the histological recovery. Because the pathological findings obtained in these damaged testes resembled to those of human male infertility, the changes in the activities of the two testicular enzymes after DBP treatment may provide a clue toward the understanding of the pathophysiological phenomena involved in clinical infertile testis.

Abstract  The short-term test has been considered to be the most practical method for the rapid screening of carcinogens. Under a project of the Ministry of Health and Welfare, 182 compounds were examined by short-term tests over six years (1973-1978), using Salmonella typhimurium TAlOO and TA98 (mutations), Bacillus subtilis (rec assay), hamster lung fibroblast cells (chromosome aberrations, sister-3 23-324 KAWACHI ET AL. chromatid exchanges), human embryo fibroblasts (chromosome aberrations, sister chromatid exchanges), bone-marrow cells (chromosome aberrations in vivo) and silk worms (mutations). Compounds were selected by a research group organized by the Ministry and included carcinogens, noncarcinogens and compounds not previously tested for carcinogenicity. They were selected from the following categories: (1) structural analogues of known carcinogens; (2) food additives widely used in Japan; (3) drugs administered for long periods to patients; and (4) industrial intermediates with a high annual production. The object of the programme is not to screen possible carcinogens in our environment but to improve the tests and to investigate the validity of newly developed rapid screening techniques. Data from short- term assays for carcinogenicity are shown in Table 1: all data c ited as 'Salmonella test' are from the Salmonella/microsome assay system. Rec assays performed during 1973 did not include metabolic activation; however, from 1975-1978, a metabolic activation system was included. The chromosome aberration test in hamster fibroblasts in vitro included a metabolic ac tivation system between 1977 and 1978: among 65 compounds tested in this way, chlorpyrifos, cochineal and Eulan U-33 were the only ones t hat required metabolic activation. The chromosomal aberration test in human fibroblasts and the sister chromatid exchange assay in human fibroblasts and hamster fibroblasts were not activated metabolically. The validation of the short- term assays is summarized in Table 2. In the Salmonella/microsome test, of 49 compounds that showed mutagenic activity, 33 (67%) were found to be carcinogenic. On the other hand, of 66 nonmutagenic compounds, 48 (73%) were noncarcinogenic. Detailed data from the Salmonella/microsome tests are given in Table 3. Results from a combination of the Salmonella/microsome test and the chromosome aberration test (in vitro, in vivo) showed better validity than other combinations of short- term assays.

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  Phthalate esters are found in a wide variety of consumer and food packing products. Hence there is widespread exposure of the human population to these chemicals. Some of the phthalate esters are known to be toxic to the developing male reproductive system. This paper derives a reference dose (RfD) for each of the phthalate esters (dibutyl phthalate, diisobutyl phthalate, butylbenzyl phthalate, diethylhexyl phthalate, dipentyl phthalate, and diisononyl phthalate) that cause these effects. As these phthalate esters cause similar adverse biological effects and have the same mechanism of action, it is appropriate in a risk assessment to consider the potential adverse effects from cumulative exposure to these chemicals using a dose addition model. This paper provides examples of a cumulative risk assessment using the hazard index and relative potency approaches from the RfDs derived from studies in laboratory animals and exposure information in people. The results of the cumulative risk assessments for both a US and a German population show that the hazard index is below one. Thus it is unlikely that humans are suffering adverse developmental effects from current environmental exposure to these phthalate esters.

Abstract  Carcinogenesis in the upper aerodigestive tract is influenced by multiple factors. Besides tobacco and alcohol consumption, specific pollutants such as phthalates, nitrosamines, and polycyclic aromatic carbohydrates may be important in tumor initiation. Genetic factors related to mutagen sensitivity and DNA repair capacity also play a role. The aim of this study was to investigate whether human peripheral blood lymphocytes and mucosal epithelium of the upper aerodigestive tract, the target for volatile and liquid xenobiotics, are equally sensitive to genotoxic agents. The Comet assay was used to detect for DNA damage induced by genotoxic agents in mucosal epithelial cells and peripheral blood lymphocytes of 60 volunteers. Mucosa was harvested from larynx, oropharynx, and inferior nasal turbinates. Xenobiotics investigated were dibutylphthalate (DBP), diisobutylphthalate (DiBP), N'-nitrosodiethylamine (NDELA), benzo[a]pyrene (B[a]P), and N'-methyl-N'-nitro-N-nitrosoguanidine (MNNG). DBP, DiBP, B[a]P, NDELA and MNNG induced a significant increase in DNA migration in both cell populations. Peripheral blood lymphocytes were more sensitive than mucosal cells to DBP and DiBP, but not to NDELA and B[a]P. The correlation, in terms of DNA migration, between lymphocytes and mucosal cells among volunteers was relatively poor. Based on the poor correlation in response between the two cell types, the sensitivity of peripheral blood lymphocytes to genotoxic agents appears to be a poor predictor of sensitivity in the target cells of the upper aerodigestive tract. Further attention should be focused on intra-individual mutagen sensitivities and inter-individual genetic differences as regards susceptibility to upper aerodigestive tract cancer.

Abstract  BACKGROUND: Phthalates are widely used chemicals, and human exposure is extensive. Recent studies have indicated that phthalates may have thyroid-disrupting properties. OBJECTIVE: We aimed to assess concentrations of phthalate metabolites in urine samples from Danish children and to investigate the associations with thyroid function, insulin-like growth factor I (IGF-I), and growth. METHODS: In 845 children 4-9 years of age, we determined urinary concentrations of 12 phthalate metabolites and serum levels of thyroid-stimulating hormone, thyroid hormones, and IGF-I. RESULTS: Phthalate metabolites were detected in all urine samples, of which monobutyl phthalate was present in highest concentration. Phthalate metabolites were negatively associated with serum levels of free and total triiodothyronine, although statistically significant primarily in girls. Metabolites of di(2-ethylhexyl) phthalate and diisononyl phthalate were negatively associated with IGF-I in boys. Most phthalate metabolites were negatively associated with height, weight, body surface, and height gain in both sexes. CONCLUSIONS: Our study showed negative associations between urinary phthalate concentrations and thyroid hormones, IGF-I, and growth in children. Although our study was not designed to reveal the mechanism of action, the overall coherent negative associations between urine phthalate and thyroid and growth parameters may suggest causative negative roles of phthalate exposures for child health.

Abstract  Phthalate esters have been extensively used as a plasticizer of synthetic polymers. Previous studies have revealed that some phthalate esters including di(n-butyl) phthalate (DBP) induce spermatogenic cell apoptosis, although its mechanism is not yet clear. The present study describes that disruption of Sertoli cell vimentin filaments by DBP administration may relate to spermatogenic cell apoptosis. The present histopathological study revealed that a single oral administration of 500 mg/kg DBP caused progressive detachment and displacement of spermatogenic cells away from the seminiferous epithelium and sloughing of them into the lumen. Degenerative spermatogenic cells characterized by chromatin condensation were frequently observed in DBP-treated rats. Ultrastructurally, the degenerative spermatogenic cells were separated from their neighbours, and a collapse of Sertoli cell vimentin filaments was recognized in DBP-treated rats. Sertoli cell cultures showed the increased number and size of vacuoles in their cytoplasm. In agreement with the in vivo experiment, vimentin filaments clearly showed a gradual collapse in DBP-exposed Sertoli cells in vitro. These in vivo and in vitro experiments indicate that DBP-induced collapse of Sertoli cell vimentin filaments may lead to detachment of spermatogenic cells, and then detached cells may undergo apoptosis because of loss of the support and nurture provided by Sertoli cells.

Abstract  Human phthalate exposure occurs as mixtures of diesters with varying activity towards testosterone-dependent development. Dibutyl (DBP), diethylhexyl (DEHP) and butylbenzyl (BBP) phthalate disrupt sexual development in the fetal rat. Dimethyl (DMP) and diethyl (DEP) phthalate do not. These differences in potency may result from differential delivery of the monophthalates to the testes or from variation in the abilities of the compounds to alter steroidogenesis. We tested five phthalates in pregnant rats (500mg/kg-d, GD12-19) and analyzed the fetal testes for corresponding monoesters (MMP, MEP, MBP, MEHP, MBeP). Testes MMP and MEP levels were 2-40-fold higher than the active monoesters, MBP and MEHP. BBP exposure led to low concentrations of MBeP, but similar MBP levels to DBP. An in vitro MA-10 cell assay measured the direct effect of monophthalates on testosterone production. MEHP inhibited LH-stimulated testosterone production at 1microM. RT-PCR confirmed down-regulation of genes associated with cholesterol transport and steroid synthesis and metabolism by MEHP. Five additional phthalates were tested for testosterone inhibition. MBP and mono-n-octyl phthalate were similar to MEHP; MMP, MEP and MBeP were poor inhibitors of testosterone production. Based on these results, differences in the phthalates' ability to interfere with sexual development in vivo appears to be more associated with differential potency for testosterone inhibition than differences in tissue doses.

Abstract  Peroxisome proliferators (PP) are a large class of structurally diverse chemicals that mediate their effects in the liver mainly through the peroxisome proliferator-activated receptor alpha (PPARalpha). Exposure to some PP results in alterations of steroid levels that may be mechanistically linked to adverse effects in reproductive organs. We hypothesized that changes in steroid levels after PP exposure are due to alterations in the levels of P450 enzymes that hydroxylate testosterone and estrogen. In testosterone hydroxylase assays, exposure to the PP, WY-14,643 (WY), gemfibrozil or di-n-butyl phthalate (DBP) led to compound-specific increases in 6beta and 16beta-testosterone and androstenedione hydroxylase activities and decreases in 16alpha, 2alpha-hydroxylase activities by all three PP. The decreases in 16alpha and 2alpha-testosterone hydroxylase activity can be attributed to a 2alpha and 16alpha- testosterone hydroxylase, CYP2C11, which we previously showed was dramatically down-regulated in these same tissues (Corton et al., 1998; Mol. Pharmacol. 54, 463-473). To explain the increases in 6beta- and 16beta-testosterone hydroxylase activities, we examined the expression of P450 family members known to carry out these functions. Alterations in the 6beta-testosterone hydroxylases CYP3A1, CYP3A2 and the 16beta-testosterone hydroxylase, CYP2B1 were observed after exposure to some PP. The male-specific estrogen sulfotransferase was down-regulated in rat liver after exposure to all PP. The mouse 6beta-testosterone hydroxylase, Cyp3a11 was down-regulated by WY in wild-type but not PPARalpha-null mice. In contrast, DEHP increased Cyp3a11 in both wild-type and PPARalpha-null mice. These studies demonstrate that PP alter the expression and activity of a number of enzymes which regulate levels of sex steroids. The changes in these enzymes may help explain why exposure to some PP leads to adverse effects in endocrine tissues that produce or are the targets of sex hormones.