OBJECTIVES: Although phthalates like dibutyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) are commonly used as plasticizers and their metabolites are especially suspected of reproductive toxicity, little is known about occupational exposure to those phthalates. The aim of this study was to assess the utility of measuring the metabolite concentrations of DBP and DEHP in serum and urine samples as an indicator of occupational exposure to those phthalates. METHODS: Phthalate metabolites were analyzed by using column-switching high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS). RESULTS: We detected phthalate metabolites in serum and urine matrices at approximately 10-fold lower than the limit of detection of those metabolites in the same matrix by LC-MS/MS without column switching, which was sufficient to evaluate concentrations of phthalate metabolites for industrial workers and the general population. CONCLUSION: The accuracy and precision of the analytical method indicate that urinary metabolite determination can be a more acceptable biomarker for studying phthalate exposure and adverse health outcomes.
Biomarkers ; Chromatography, Liquid ; Dibutyl Phthalate ; Diethylhexyl Phthalate ; Humans ; Limit of Detection ; Occupational Exposure ; Phthalic Acids ; Plasticizers ; Plastics ; Tandem Mass Spectrometry

OBJECTIVETo understand the dietary consumption of residents in Xiamen and the content of phthalic acid esters (PAEs) in food, and to assess the plasticizer exposure risk of diet in Xiamen.

METHODSThe survey was conducted by stratified cluster random sampling method in Xiamen from September to October in 2010. According to the Xiamen administrative division, six neighborhood communities were selected as sampling units, then 25 families were randomly chosen from each sampling units.From the above 150 families, the permanent residents over the age of six were permitted to our study. The survey included 495 residents totally. These participants' information, such as basic personal information, physical activity levels, meal frequency and the average consumption of 33 kinds of food in 13 categories were collected using questionnaires. Thirteen categories included cereal and tubers, beans, vegetables, fungi and algae, fruits, dairy products, meat, seafood, eggs, snacks, beverages, cooking oil and spices. The height and weight of residents were measured and the average daily dietary intake was calculated. Thirty-three kinds of food in 13 categories were collected in supermarkets in Xiamen. According to the annual sales ranking, the top three-five brands of each kinds of food were selected and numbered, then two or three brands were chosen by random number table method from them; three completely individual packed samples in the same batch of each brand were detected; 243 samples were included in our study.100-500 g solid samples or 100-500 ml liquid samples were collected. The content of diethyl phthalate (DEP), dibutyl phthalate (DBP), di (2-ethylhexyl) phthalate (DEHP) in food were detected by liquid chromatography mass spectrometry, which expressed by median (minimum-maximum). The exposure dose, contribution rate and risk index of PAEs were calculated by point estimation method.

RESULTSAccording to the average daily dietary intake of residents in Xiamen, the top three ones in 13 categories of food were cereal and tubers (337.16 g/d, 18.21%), vegetables (309.12 g/d, 16.69%) and fruits (213.20 g/d, 11.51%). The content of DEP, DBP or DEHP among different categories of food was significantly different (χ² values were 58.05, 50.19 and 102.10, P < 0.01). Among 13 categories of food, seafood contained the most DEP (0.090 (0.000-0.324)mg/kg); cooking oil had the most DBP (0.700(0.000-2.980) mg/kg) and DEHP (5.115(0.000-24.160) mg/kg). DEP, DBP and DEHP exposure(0.19, 4.20, 18.10 µg × kg⁻¹ ×d ⁻¹)in dietary food in Xiamen were less than the reference dose(RfD) (800, 100, 20 µg × kg⁻¹ × d⁻¹) proposed by the United States Environmental Protection Agency (EPA), and the risk indexes were 0.02%, 4.20% and 90.50%, respectively. Among 13 categories of foods, seafood was the main source of DEP dietary exposure. The exposure dose and contribution rate of DEP in seafood were 0.18 µg × kg⁻¹ × d⁻¹ and 94.74%, respectively.Vegetables were the main source of DBP and DEHP dietary exposure. The exposure dose and contribution rate of DBP and DEHP were 1.48 µg × kg⁻¹ × d⁻¹, 35.24% and 6.07 µg × kg⁻¹ × d⁻¹, 33.54%, respectively.

CONCLUSIONThe food consumed by residents in Xiamen was overall in a safe state, but to some extent, there still exists DEHP exposure risk in foods.

China ; Dibutyl Phthalate ; Diet ; Diethylhexyl Phthalate ; Food Contamination ; Humans ; Phthalic Acids ; Plasticizers ; Risk Assessment ; Seafood ; United States ; Vegetables

OBJECTIVETo explore types of organic components and pollution level of di-n-butyl phthalate (DBP) between human milk and cow milk products.

METHODSForty healthy postpartum women with an average age of (27.44 ± 3.43) years old were selected, and a 5 ml sample of breast milk were collected. Four different brands of fresh cow milk and 1 brand of milk powder were randomly selected in the market. A total of 15 samples were collected with 3 from each brand, and the qualitative analysis of types of organic components and quantitative analysis of DBP were conducted by gas-chromatography and mass-spectrometry (GC/MS) method.

RESULTSA total of 176 different types of organic components were detected in 40 samples of human milk (averaged at (10.58 ± 4.16) types per sample); 37 different types were detected in 12 samples of fresh cow milk (averaged at (8.67 ± 1.61) types per sample); while 31 types of organic components were detected in 3 samples of milk powder (averaged at (12.67 ± 0.58) types per sample). It was obvious that the types of organic components in milk powder were significantly higher than the other two groups (t = 2.09, 4.00, P < 0.05). The most frequent organic component in human milk and cow milk was 9-octadecenoic acid (45.00% (18/40) in human milk; 53.33% (8/15) in cow milk). DBP concentrations were (57.78 ± 35.42) µg/L, (20.76 ± 6.60) µg/L and (0.45 ± 0.05) mg/kg (equal to (66.78 ± 7.60) µg/L) in human milk, fresh cow milk and milk powder, respectively. The DBP concentration in fresh cow milk was significantly lower than those in human milk and milk powder (t = 37.02, 46.02, P < 0.05).

CONCLUSIONBoth human milk and cow milk contain different types of organic pollutants, some of which have toxic effects on reproduction and human development.

Adult ; Animals ; Cattle ; Dibutyl Phthalate ; analysis ; Diethylhexyl Phthalate ; analysis ; Environmental Pollutants ; analysis ; Female ; Humans ; Milk ; chemistry ; Milk, Human ; chemistry

OBJECTIVES: Maintaining the constant exposure to hydrophobic organic compouds in acute toxicity tests is one of the most difficult issues in the evaluation of their toxicity and corresponding risks. Passive dosing is an emerging tool to keep constant aqueous concentration because of the overwhelming mass loaded in the dosing phase. The primary objectives of this study were to develop the constant exposure condition for an acute mortality test and to compare the performance of the passive dosing method with the conventional spiking with co-solvent. METHODS: A custom cut polydimethylsiloxane (PDMS) tubing loaded with benzyl butyl phthalate (BBP) was placed in each well of a 24-well plate containing assay medium. The rate of the release of BBP from PDMS was evaluated by measuring the change in the concentration of BBP in the assay medium. The efficiency of maintaining constant exposure condition was also evaluated using a simple two-compartment mass transport model employing a film-diffusion theory. An acute mortality test using 10 C. elegans in each well was conducted for the evaluation of the validity of passive dosing and the comparative evaluation of the passive dosing method and the conventional spiking method. RESULTS: Free concentration in the assay medium reached 95% steady state value within 2.2 hours without test organisms, indicating that this passive dosing method is useful for an acute toxicity test in 24 hours. The measured concentration after the mortality test agreed well with the estimated values from partitioning between PDMS and the assay medium. However, the difference between the nominal and the free concentration became larger as the spiked concentration approached water solubility, indicating the instability of the conventional spiking with a co-solvent. CONCLUSIONS: The results in this study support that passive dosing provides a stable exposure condition for an acute toxicity test. Thus, it is likely that more reliable toxicity assessment can be made for hydrophobic chemicals using passive dosing.
Benzophenones ; Biological Availability ; Boronic Acids ; Caenorhabditis ; Caenorhabditis elegans ; Dibutyl Phthalate ; Dimethylpolysiloxanes ; Phthalic Acids ; Solubility ; Toxicity Tests, Acute

OBJECTIVETo detect the differential expression of Notch1 in the genital tubercle (GT) of fetal male rats with hypospadias induced by maternal exposure to Di-n-butyl phthalate (DBP) and that in normal control fetal rats in order to further explore the role of Notch1 in DBP-induced hypospadias.

METHODSTwenty pregnant SD rats were equally and randomly divided into an experimental and a control group, the former given DBP and the latter soybean oil intragastrically at 800 mg/(kg x d) and 2 ml/d respectively from gestation day (GD) 14 to GD 18. On GD 19, the birth weight (BW), anogenital distance (AGD) and hypospadias incidence were recorded, GTs of the fetal male rats collected, and the expression of Notch1 analyzed by Western blot and immunohistochemistry.

RESULTSThe BW of the fetal male rats was (4.40 +/- 0.30) g in the experimental group, significantly lower than (6.11 +/- 0.40) g in the control (P <0.05), and the AGD was (2.17 +/- 0.18) mm in the former, markedly shorter than (3.28 +/- 0.16) mm in the latter (P<0.05). The incidence of hypospadias was 42.9%. The relative expression of Notch1 was remarkably lower in the hypospadiac rats than in the normal controls (0.671 +/- 0.021 vs 1.327 +/- 0.031, P<0.05), and it was mainly located in the epithelial cells of the GT. The staining intensity was obviously weaker in the hypospadias than in the normal control group.

CONCLUSIONDBP has an obvious toxic effect on fetal male rats and can change the expression of Notch1 in the GT. It possibly affects cell proliferation and apoptosis and epithelial-to-mesenchymal transition (EMT), resulting in the occurrence of hypospadias.

Animals ; Dibutyl Phthalate ; toxicity ; Female ; Fetus ; Hypospadias ; chemically induced ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Receptor, Notch1 ; metabolism

OBJECTIVETo study the reversibility of di-n-butyl phthalate (DBP) effects on F(1) generation rat testes.

METHODSPregnant rats were treated with different dose of DBP (0, 50, 250 and 500 mg per kg per day) by gavage from GD1 to PND21. The adverse effects of DBP on testes of F(1) male rats in different developmental period (PND14, 21 and 70) were observed by anatomy and pathological methods.

RESULTSThere was no difference in rat testis weight and testis/body weight between DBP-treated group and the control. From the results of pathology and sertoli cell counting, comparing with the control, thinner seminiferous epithelium, decreased cell number and vacuole cells were observed in PND14 male DBP-treated rats. In PND21 rats, the number and form of sertoli cells were recovered and few exfoliated spermatogenic cells were found. When maturing to PND70, few rats were found irreversible damages such as seminiferous tubule degeneration, seminiferous epithelium atrophy, etc.

CONCLUSIONThese results suggest that adverse effects of DBP on young rat testes should be reversibility.

Animals ; Dibutyl Phthalate ; toxicity ; Female ; Male ; Rats ; Rats, Sprague-Dawley ; Sertoli Cells ; pathology ; Testis ; drug effects ; pathology

OBJECTIVETo study the preparation of seeding type immobilized microorganisms and their degradation characteristics on di-n-butyl phthalate (DBP).

METHODSDiatomite, clinoptilolite, silk zeolite, and coal fly ash were chosen as reserved materials and modified. Their adsorption capacity and intensity in the bacteria were determined and the best carrier was picked out. The seeding type immobilized microorganisms were prepared by the best carrier and then it degraded DBP under different primary concentration, vibration rate, pH, temperature in the presence of metal compounds.

RESULTSThe adsorption capacity of the modified coal fly ash, silk zeolite, clinoptilolite and zeolite was 44.2%, 71.6%, 84.0%, and 94.4%, respectively, which was 1.66, 1.49, 1.37, and 1.16 times as high as that of their natural state. Their adsorption intensity was 72.1%, 90.5%, 90.1%, and 91.1% in turn. The modified diatomite was selected to prepare the seeding type immobilized microorganisms. When the primary DBP concentration was 100 to 500 mg/L, the DBP-degraded rate of the immobilized microorganisms could be above 80%. The degradation activity of both the dissociative and immobilized microorganisms was higher in vibration than in stillness. When pH was 6.0 to 9.0, the DBP-degraded rate of the immobilized microorganisms was above 82%, which was higher than the dissociative microorganisms. When the temperature was between 20 degrees C and 40 degrees C, the DBP-degraded rate could reach 84.5% in 24 h. The metal compounds could inhibit the degradation activity of both the dissociative and immobilized microorganisms. The degradation process of the immobilized microorganisms could be described by the first-order model.

CONCLUSIONThe adsorption capacity of the diatomite, clinoptilolite, silk zeolite and coal fly ash on DBP-degrading bacteria can be improved obviously after they are modified. The modified diatomite is best in terms of its adsorption capacity and intensity. Its seeding type immobilized microorganisms could degrade DBP effectively and is more adaptable to DBP load, temperature, pH than the dissociative microorganisms. The metal compounds could inhibit the activity of both the immobilized and dissociative microorganisms. The degradation reaction of the immobilized microorganisms on DBP is consistent with the first-order model.

Adsorption ; Bacteria ; metabolism ; Biodegradation, Environmental ; Biotechnology ; methods ; Cells, Immobilized ; Diatomaceous Earth ; Dibutyl Phthalate ; metabolism ; Hydrogen-Ion Concentration ; Kinetics ; Temperature ; Zeolites

OBJECTIVETo investigate the effects of prepubertal continuous exposure to dibutyl phthalate (DBP) on the testis development in SD rats.

METHODSTwenty-one-day-old weanling prepubertal male SD rats were randomly divided into a control (n = 24) and an experiment group (n = 54), gavaged daily with corn oil vehicle or corn oil + DBP at the repeated dose of 0 mg/(kg x d) (control), 50 mg/(kg x d) (low-dose), 200 mg/(kg x d) (medium-dose) and 600 mg/(kg x d) (high-dose) for 14, 21 and 28 days, and then sacrificed by decapitation on PND35, PND42 and PND49. The body weight gain, the testis weight and volume and the weight of accessory sex organs were measured, the serum testosterone level assayed by chemoluminescence technique, the testis tissues stained by H&E and observed under the light microscope for morphological alteration, the mean diameter of the seminiferous tubules determined and testicular biopsy scores obtained.

RESULTSDisordered arrangement of spermatogenic cells was found in some seminiferous tubules on PND35 in the low-dose group, but testis development and spermatogenesis were normal on PND42 and PND49. In the medium-dose group, disordered arrangement and decreased number of spermatogenic cells were observed on PND35 and PND42, but without testicular atrophy, and various grades of spermatogenic cells and sperm were seen on PND49. High-dose DBP slowed down the body weight gain, decreased serum T levels and induced degeneration of seminiferous tubules, arrest of spermatogenic epithelium development and necrosis of spermatogenic cells. The pubertal rats (PND49) showed testicular atrophy, azoospermia and delayed development of accessory sex organs.

CONCLUSIONPrepubertal continuous exposure to DBP induces damages to testicular development and spermatogenesis in a dose-dependent manner, and those induced by high-dose DBP cannot be recuperated in the phase of prepubertal development, while the slight adverse effects on the testis induced by low- and medium-dose DBP could be completely or partly reversible before PND49.

Animals ; Dibutyl Phthalate ; toxicity ; Environmental Exposure ; Growth ; drug effects ; Male ; Rats ; Rats, Sprague-Dawley ; Testis ; drug effects ; growth & development

Animals ; Benzo(a)pyrene/toxicity* ; Cytokines ; Dibutyl Phthalate/toxicity* ; Female ; Liver ; Male ; NF-kappa B ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo evaluate the effects of di-butyl phthalate(DBP) on the sperm motility and oxidative stress in rats.

METHODSHealthy 6-week-old male Sprague Dawlay rats were randomly divided into 4 groups with 8 in each group. DBP dissolved in peanut oil was administered by gavage at dosage of 0, 250, 500, 1,000 mg/(kg.d). After 4-week DBP exposure, the animals were killed and the organs were selected and weighed. The sperm VCL, VSL, VAP, BCF, ALH, LIN, MAD and STR in the cauda epididymis were assessed by computer assisted sperm analysis (CASA), and the activities of superoxide dismutase (SOD) and the contents of malondialdehyde (MDA) in serum and testis homogenate were measured simultaneously. The increase of body weight per day and the organ body weight ratio changes of the liver, testes and epididymides were also observed.

RESULTSThe liver organ body weight ratios of the treated groups were higher than those of the control (P < 0.01), while the testis organ body weight ratios were lower at dosage of 1,000 mg/(kg.d) DBP. Compared with the control group, the parameters of rat sperm VCL and ALH declined significantly at dosage of 1,000 mg/(kg.d) DBP. In addition, DBP showed inhibiting effect on SOD activities in the testis, and it was significant in the highest exposure group compared with the control (P < 0.05). However, there were no differences in serum SOD activities between the treated groups and the control.

CONCLUSIONDBP exposure may affect the sperm motility and the anti-oxidative systems. The testis is a vital target organ influenced by DBP.

Animals ; Dibutyl Phthalate ; toxicity ; Dose-Response Relationship, Drug ; Male ; Oxidative Stress ; drug effects ; Rats ; Rats, Sprague-Dawley ; Sperm Motility ; drug effects