Age as a determinant of phosphate flame retardant exposure of the Australian population and identification of novel urinary PFR metabolites

The demand for alternative flame retardant materials such as phosphate flame retardants and plasticizers (PFRs) is increasing, although little is known of their possible effects on human health and development. To date, no information on the exposure of children or general Australian population to PFRs is available. The objectives of this study were to characterize the average levels and age-related patterns of PFR metabolites in urine in the general Australian population and to identify novel hydroxylated PFR metabolites in urine. Surplus pathology urine samples from Queensland, Australia were stratified and pooled by age and sex (3224 individuals aged 0 to 75 years into 95 pools) according to two different pooling strategies at two different time periods. Samples were analyzed by solid phase extraction and liquid chromatography–tandem mass spectrometry following enzymatic treatment. Nine PFR metabolites were measured in the Australian population, including the first report of a hydroxylated metabolite of TCIPP (BCIPHIPP). Diphenyl phosphate (DPHP), BCIPHIPP and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) were detected in > 95% of samples. DPHP, a metabolite of aryl-PFRs, was found in several samples at levels which were one order of magnitude higher than previously reported (up to 730 ng/mL). Weighted linear regression revealed a significant negative association between log-normalized BDCIPP and DPHP levels and age (p < 0.001). Significantly greater levels of BDCIPP and DPHP were found in children's urine compared with adults, suggesting higher exposure to PFRs in young children. BCIPHIPP was identified for inclusion in future PFR biomonitoring studies.     

Assessment of human hair as an indicator of exposure to organophosphate flame retardants. Case study on a Norwegian mother–child cohort

A major challenge of non-invasive human biomonitoring using hair is to assess whether it can be used as an indicator of exposure to Flame Retardants, such as Organophosphate Flame Retardants (PFRs), since the contribution of atmospheric deposition (air and/or dust) cannot be neglected. Therefore, the aim of this study was to evaluate the suitability of using human hair more thoroughly by comparison of (i) levels of PFRs in human hair (from 48 mothers and 54 children), with levels measured in dust and air in their respective households; and (ii) levels of selected PFRs in hair with the levels of corresponding PFR metabolites in matching urine samples collected simultaneously. Most PFRs (tri-n-butyl phosphate (TNBP), 2-ethyl-hexyldiphenyl phosphate (EHDPHP), tri-phenyl phosphate (TPHP), tri-iso-butyl phosphate (TIBP), and tris(2-butoxyethyl) phosphate (TBOEP)) were detected in all human hair samples, tris(2-ethylhexyl) phosphate (TEHP) and tris(1,3-dichloro-iso-propyl) phosphate (TDCIPP) in 93%, tri-cresyl-phosphate (TCP) in 69% and tris(2-chloroethyl) phosphate (TCEP) in 21% of the samples. Levels of individual PFRs ranged between < 1 and 3744 ng/g hair and were lower than in indoor dust from the participants' homes. Several statistically significant associations between PFR levels in human hair and PFR levels in house dust and/or air were found, e.g. Spearman correlation (r_S = 0.561, p < 0.05) between TBOEP in children's hair and in indoor air. Also, associations were found between TDCIPP in hair and its metabolite bis(1,3-dichloro-iso-propyl) phosphate (BDCIPP) in urine; they were stronger for children (e.g. Pearson correlation r_P = 0.475; p = 0.001) than for mothers (r_P = 0.395, p = 0.01). Levels of diphenyl phosphate (DPHP) in mothers' and children's urine were slightly correlated (r_S = 0.409, p = 0.008), suggesting similar sources of exposure. To the best of our knowledge, this is the first study with such design and our findings might help to understand human exposure to and body burdens of PFRs.     

Urinary biomarkers of flame retardant exposure among collegiate U.S. gymnasts

Flame retardants are widely used in polyurethane foam materials including gymnastics safety equipment such as pit cubes and landing mats. We previously reported elevated concentrations of flame retardants in the air and dust of a U.S. gymnastics training facility and elevated PentaBDE in the serum of collegiate gymnasts. Our objective in this pilot study was to compare urinary biomarkers of exposure to other flame retardants and additives of polyurethane foam including tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), triphenyl phosphate (TPHP) and 2-ethylhexyl- 2,3,4,5-tetrabromobenzoate (EH-TBB) in samples collected from 11 collegiate gymnasts before and after a gymnastics practice (n = 53 urine samples total). We identified a 50% increase in the TPHP biomarker (p = 0.03) from before to after practice, a non-significant 22% increase in the TDCIPP biomarker (p = 0.14) and no change for the EH-TBB biomarker. These preliminary results indicate that the gymnastics training environment can be a source of recreational exposure to flame retardants. Such exposures are likely widespread, as we identified flame retardants in 89% of foam samples collected from gyms across the U.S.     

Human exposure pathways to organophosphate triesters — A biomonitoring study of mother–child pairs

The worldwide ban of several formulations of brominated flame retardants has caused an increase in the production of organophosphorus flame retardants (PFRs) to meet the existing fire regulations for a wide range of household products. This biomonitoring study surveys the occurrence of the metabolites from PFRs and related plasticizers (dialkyl and diaryl phosphates; DAPs) in urine from a Norwegian mother–child cohort (48 mothers and 54 children). Concentrations of DAPs were higher in the children than in their mothers (Wilcoxon signed-rank test p = 0.001). Median urinary concentrations of diphenyl phosphate (DPHP) were 1.1 and 0.51 ng/mL in children and mothers, respectively, followed by bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) with medians of 0.23 and 0.12 ng/mL, respectively. Detection frequencies for bis(2-butoxyethyl) phosphate (BBOEP) in urine from children and mothers were 32 and 1%, respectively (median < 0.18 ng/mL), and for di-n-butyl phosphate (DNBP) 15 and 8%, respectively (median < 0.12 ng/mL). The concentrations of DPHP and BDCIPP in urine from children were significantly correlated with those found for their parent compounds in air and dust from the households (Spearman's rank correlations 0.30 < R_s < 0.36; p < 0.05). For mothers, only the urinary concentration of BDCIPP was correlated to its precursor in dust from the households (R_s = 0.40; p < 0.01), which might indicate higher impact of the household environment on children than mothers. A diurnal variability study of the mothers' urinary concentrations of DPHP and BDCIPP showed lower concentrations at time periods when women were likely to be outside the household. In contrast, no relevant associations between organophosphate metabolites in urine and food consumption data obtained through a 24 hour recall were seen. This suggests that the residential environment is a more important exposure pathway to PFRs than the diet.     

Flame retardants and organochlorines in indoor dust from several e-waste recycling sites in South China: Composition variations and implications for human exposure

Several classes of flame retardants, such as polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), dechlorane plus (DPs), and organophosphate flame retardants (PFRs), together with polychlorinated biphenyls (PCBs) were measured in indoor dust from five villages located in three e-waste recycling regions in Guangdong Province, South China. The medians of PBDEs, NBFRs, and PFRs in dust in five sites ranged from 685–67,500, 1460–50,010, and 2180–29,000 ng/g, respectively. These concentrations were much higher than the medians of PCBs (52–2900 ng/g). BDE 209 and decabromodiphenyl ethane (DBDPE) were the two major halogen flame retardants in dust, while tris-(1-chloro-2-propyl) phosphate (TCIPP) and triphenyl phosphate (TPHP) were the major PFRs. Principle component analysis revealed the different pollutant patterns among different sites. The estimated median human exposures of PBDEs, NBFRs, PFRs, and PCBs via dust ingestion were 1.1–24.1, 0.73–20.3, 1.36–23.5, and 0.04–0.93 ng/kg bw/day for adults, and 16.2–352, 10.7–296, 19.9–343, 0.05–0.61, 0.65–13.6 ng/kg bw/day for toddlers, respectively. Residents from Site 5 had the highest exposure (95 percentile levels and high dust ingestion for toddlers) of PBDEs (3920 ng/kg bw/day), NBFRs (3200 ng/kg bw/day), and PFRs (5280 ng/kg bw/day). More attention should be paid to the contamination with NBFRs and PFRs, instead of PCBs, in these e-waste recycling regions, and local public health threat from PBDE alternatives should remain of concern. To the best of our knowledge, this is the first study on human exposure assessment of PFRs at e-waste sites.     

Urinary concentrations of organophosphate and carbamate pesticides in residents of a vegetarian community

Few population studies have measured urinary levels of pesticides in individuals with vegan, vegetarian, or organic diets. The objectives of this study were to evaluate whether a vegan/vegetarian diet was associated with increased exposure to organophosphate and carbamate pesticides, and to evaluate the impact of organic consumption on pesticide exposure in vegans and vegetarians. In the current pilot study conducted in 2013–2014, we collected spot urine samples and detailed 24 h recall dietary data in 42 adult residents of Amirim, a vegetarian community in Northern Israel. We measured urinary levels of non-specific organophosphate pesticide metabolites (dialkylphosphates, (DAPs)) and specific metabolites of the current-use pesticides chlorpyrifos (3,5,6-trichloro-2-pyridinol (TCPy)), propoxur (-isopropoxyphenol (IPPX)), and carbaryl (1-naphthol). Six DAP metabolites were detected in between 67 and 100% of urine samples, with highest geometric mean concentrations for dimethylphosphate (19.2 μg/g). Creatinine-adjusted median concentrations of total DAPs and of TCPy were significantly higher in Amirim residents compared to the general Jewish population in Israel (0.29 μmol/g compared to 0.16, p < 0.05 for DAPs and 4.32 μg/g compared to 2.34 μg/g, p < 0.05 for TCPy). Within Amirim residents, we observed a positive association between vegetable intake and urinary TCPy levels (rho = 0.47, p < 0.05) and lower median total dimethyl phosphate levels in individuals reporting that > 25% of the produce they consume is organic (0.065 μmol/L compared to 0.22, p < 0.05). Results from this pilot study indicate relatively high levels of urinary organophosphate pesticide metabolite concentrations in residents of a vegetarian community, a positive association between vegetable intake and urinary levels of a chlorpyrifos specific metabolite, and lower levels of total dimethyl phosphate in individuals reporting higher intake of organic produce. Results suggest that consumption of organic produce may offer some protection from increased exposure to organophosphate pesticide residues in vegetarians.     

Protective glove use and hygiene habits modify the associations of specific pesticides with Parkinson's disease

Pesticides have been associated with Parkinson's disease (PD), and protective gloves and workplace hygiene can reduce pesticide exposure. We assessed whether use of gloves and workplace hygiene modified associations between pesticides and PD. The Farming and Movement Evaluation (FAME) study is a nested case–control study within the Agricultural Health Study. Use of protective gloves, other PPE, and hygiene practices were determined by questionnaire (69 cases and 237 controls were included). We considered interactions of gloves and hygiene with ever-use of pesticides for all pesticides with ≥ 5 exposed and unexposed cases and controls in each glove-use stratum (paraquat, permethrin, rotenone, and trifluralin). 61% of respondents consistently used protective gloves and 87% consistently used ≥ 2 hygiene practices. Protective glove use modified the associations of paraquat and permethrin with PD: neither pesticide was associated with PD among protective glove users, while both pesticides were associated with PD among non-users (paraquat OR 3.9 [95% CI 1.3, 11.7], interaction p = 0.15; permethrin OR 4.3 [95% CI 1.2, 15.6] interaction p = 0.05). Rotenone was associated with PD regardless of glove use. Trifluralin was associated with PD among participants who used < 2 hygiene practices (OR 5.5 [95% CI 1.1, 27.1]) but was not associated with PD among participants who used 2 or more practices (interaction p = 0.02). Although sample size was limited in the FAME study, protective glove use and hygiene practices appeared to be important modifiers of the association between pesticides and PD and may reduce risk of PD associated with certain pesticides.     

Monitoring exposure to polycyclic aromatic hydrocarbons in an Australian population using pooled urine samples

Integrated exposure to polycyclic aromatic hydrocarbons (PAHs) can be assessed through monitoring of urinary mono-hydroxylated PAHs (OH-PAHs). The aim of this study was to provide the first assessment of exposure to PAHs in a large sample of the population in Queensland, Australia including exposure to infant (0–4 years). De-identified urine specimens, obtained from a pathology laboratory, were stratified by age and sex, and pooled (n = 24 pools of 100) and OH-PAHs were measured by gas chromatography–isotope dilution–tandem mass spectrometry. Geometric mean (GM) concentrations ranged from 30 ng/L (4-hydroxyphenanthrene) to 9221 ng/L (1-naphthol). GM of 1-hydroxypyrene, the most commonly used PAH exposure biomarker, was 142 ng/L. The concentrations of OH-PAHs found in this study are consistent with those in developed countries and lower than those in developing countries. We observed no association between sex and OH-PAH concentrations. However, we observed lower urinary concentrations of all OH-PAHs in samples from infants (0–4 years), children (5–14 years) and the elderly (> 60 year old) compared with samples from other age groups (15–29, 30–44 and 45–59 years) which may be attributed to age-dependent behaviour-specific exposure sources.     

Evaluation of 3D-human skin equivalents for assessment of human dermal absorption of some brominated flame retardants

Ethical and technical difficulties inherent to studies in human tissues are impeding assessment of the dermal bioavailability of brominated flame retardants (BFRs). This is further complicated by increasing restrictions on the use of animals in toxicity testing, and the uncertainties associated with extrapolating data from animal studies to humans due to inter-species variations. To overcome these difficulties, we evaluate 3D-human skin equivalents (3D-HSE) as a novel in vitro alternative to human and animal testing for assessment of dermal absorption of BFRs. The percutaneous penetration of hexabromocyclododecanes (HBCD) and tetrabromobisphenol-A (TBBP-A) through two commercially available 3D-HSE models was studied and compared to data obtained for human ex vivo skin according to a standard protocol. No statistically significant differences were observed between the results obtained using 3D-HSE and human ex vivo skin at two exposure levels. The absorbed dose was low (less than 7%) and was significantly correlated with log K_ow of the tested BFR. Permeability coefficient values showed increasing dermal resistance to the penetration of γ-HBCD > β-HBCD > α-HBCD > TBBPA. The estimated long lag times (> 30 min) suggests that frequent hand washing may reduce human exposure to HBCDs and TBBPA via dermal contact.     

Daily intake of bisphenol A and triclosan and their association with anthropometric data,thyroid hormones and weight loss in overweight and obese individuals

Bisphenol A (BPA) and triclosan (TCS) were determined in urine of Belgian overweight and obese (n = 151) and lean (n = 43) individuals. After the first urine collection (0 M), obese patients started a diet program or have undergone bariatric surgery. Hereafter, three additional urine samples from obese patients were collected after 3 (3 M), 6 (6 M) and 12 (12 M) months. Both compounds were detected in > 99% of the samples. BPA had median concentrations of 1.7 and 1.2 ng/mL in obese and lean groups, respectively, while TCS had median concentrations of 1.5 and 0.9 ng/mL in the obese and lean groups, respectively. The obese group had higher urinary concentrations (ng/mL) of BPA (p < 0.5), while no significant differences were found for TCS between the obese and lean groups. No time trends between the different collection moments were observed. The BPA concentrations in the obese group were negatively associated with age, while no gender difference or relationship with body mass index was observed. For TCS, no relationships with gender, BMI, or age were found. The temporal variability of BPA and TCS was assessed with calculation of the intraclass correlation coefficient, Spearman rank correlation coefficients, and surrogate category analysis. We observed evidence that single spot urine samples might be predictive of exposure over a longer period of time. Dietary intakes of BPA and TCS did not differ significantly among the time points considered after obese individuals started losing weight (6 and 12 months). Multiple linear regression analyses after adjusting for age and weight loss revealed negative associations between urinary TCS and serum FT4 in the 0 M and 3 M female obese individuals and positive associations between urinary BPA and serum TSH in the lean group.     

Biomonitoring short- and long-term exposure to the herbicide terbuthylazine in agriculture workers and in the general population using urine and hair specimens

The aim of this work was to evaluate short-term and long-term exposure to terbuthylazine (TBA) in agriculture workers (AW), rural residents (RR), and urban residents (UR) using urine and hair specimens. Twelve AW, 13 RR, and 17 UR were included in the study. Urine spot samples were collected with two different protocols. AW urine samples were collected before the application season (February, U₀), at bedtime on the day of TBA application (March–May, U₁), and prior to the next shift on the day after TBA application (U₂). RR and UR urine samples were collected on any day during the application season (U_e). Hair samples were collected for all subjects before the application season (February, H₀) and at the end of the season (June, H₁). TBA and its metabolite desethylterbuthylazine (DET) were measured by liquid chromatography coupled with triple quadrupole mass spectrometry detection. DET was exclusively found in urine, while TBA was mostly found in the hair. In the AW, the urinary levels of DET were not detected in the U₀ samples, and they increased to median levels of 1.81 and 2.94 μg/L in the U₁ and U₂ samples, respectively (p < 0.001). In the RR and UR, DET was not detected in the U_e samples. In the UR, TBA was not detected in the H₀ samples, and the median levels of TBA were 0.01 ng/mg hair in both the AW and RR. In the H₁ samples, the median TBA levels were not detected, 0.01, and 0.08 ng/mg hair in the UR, RR, and AW, respectively (p < 0.001). Urinary DET and hair TBA are promising candidates for biomonitoring short- and long-term exposure to TBA. The use of this herbicide in agriculture leads to exposure in rural residents.     

Multimycotoxin analysis in urines to assess infant exposure: A case study in Cameroon

This study was conducted to investigate mycotoxin exposure in children (n = 220, aged 1.5–4.5 years) from high mycotoxin contamination regions of Cameroon and to examine the association between the mycotoxin levels (in total 18 analytes) and several socio-demographic factors and anthropometric characteristics. A cross-sectional study was conducted in six villages in Cameroon with 220 children. Mycotoxins and their metabolites were detected in 160/220 (73%) urine samples.There were significant differences in the mean contamination levels of ochratoxin A (p = 0.01) and β-zearalenol (p = 0.017) between the two agro-ecological zones investigated. Likewise significant differences were observed in the mean levels of aflatoxin M₁ (p = 0.001) across the weaning categories of these children. The mean concentration of aflatoxin M₁ detected in the urine of the partially breastfed children (1.43 ng/mL) was significantly higher (p = 0.001) than those of the fully weaned children (0.282 ng/mL).Meanwhile, the mean concentrations of deoxynivalenol (3.0 ng/mL) and fumonisin B₁ (0.59 ng/mL) detected in the urine of the male children was significantly (p value 0.021 for deoxynivalenol and 0.004 for fumonisin B₁) different from the levels detected in the urine of female children; 0.71 ng/mL and 0.01 ng/mL for deoxynivalenol and fumonisin B₁ respectively. In this study, there was no association between the different malnutrition categories (stunted, wasting and underweight) and the mycotoxin concentrations detected in the urine of these children.However, there is sufficient evidence to suggest that children in Cameroon under the age 5 are exposed to high levels of carcinogenic substances such as fumonisin B₁, aflatoxin M₁ and ochratoxin A through breastfeeding. To the best of our knowledge, this is the first report of its kind carried out in West Africa to determine multi-mycotoxin exposure in infants.     

Identification of fipronil metabolites by time-of-flight mass spectrometry for application in a human exposure study

Fipronil is a phenylpyrazole insecticide commonly used in residential and agricultural applications. To understand more about the potential risks for human exposure associated with fipronil, urine and serum from dosed Long Evans adult rats (5 and 10 mg/kg bw) were analyzed to identify metabolites as potential biomarkers for use in human biomonitoring studies. Urine from treated rats was found to contain seven unique metabolites, two of which had not been previously reported—M4 and M7 which were putatively identified as a nitroso compound and an imine, respectively. Fipronil sulfone was confirmed to be the primary metabolite in rat serum. The fipronil metabolites identified in the respective matrices were then evaluated in matched human urine (n = 84) and serum (n = 96) samples from volunteers with no known pesticide exposures. Although no fipronil or metabolites were detected in human urine, fipronil sulfone was present in the serum of approximately 25% of the individuals at concentrations ranging from 0.1 to 4 ng/mL. These results indicate that many fipronil metabolites are produced following exposures in rats and that fipronil sulfone is a useful biomarker in human serum. Furthermore, human exposure to fipronil may occur regularly and require more extensive characterization.     

Monocyclic and bicyclic monoterpenes in air of German daycare centers and human biomonitoring in visiting children,the LUPE 3 study

To investigate the assumed association between indoor air pollution with monoterpenes (MTps) and the internal MTp exposure of occupants, a comparative study was performed in daycare centers in two federal states of Germany. Three well-known monoterpenoid air pollutants, viz. α-pinene (αPN), Δ³-carene (CRN), and R-limonene (LMN), were measured in indoor air in 45 daycare centers. Additionally, urine samples of 222 children visiting these facilities were collected in the evening after a full-day stay. Altogether 11 MTp metabolites were analyzed in the urine samples using a novel highly sensitive and selective gas chromatographic–tandem-mass spectrometric procedure. The medians (95th percentiles) of the MTp levels in indoor air were 9.1 μg m^− 3 (94 μg m^− 3) for LMN, 2.6 μg m^− 3 (13 μg m^− 3) for αPN, and < 1.0 μg m^− 3 (3.2 μg m^− 3) for CRN. None of the day care centers exceeded the German health precaution or hazard guide value. In spite of the low MTp air exposure, the urine analyses revealed an exposure to the three monoterpenes in almost all children. The median levels of MTp metabolites in urine were 0.11 mg L^− 1 for LMN-8,9-OH, 0.10 mg L^− 1 for LMN-1,2-OH, 49 μg L^− 1 for PA, 2.9 μg L^− 1 for POH, 5.2 μg L^− 1 for tCAR, and 4.1 μg L^− 1 for cCAR (LMN metabolites), 7.2 μg L^− 1 for MYR, 19 μg L^− 1 for tVER, and 19 μg L^− 1 for cVER (αPN metabolites), as well as 8.2 μg L^− 1 for CRN-10-COOH (CRN metabolite). Statistically significant and strong correlations among the urinary metabolites of each MTp were found. Moreover, statistical associations between LMN metabolites and the LMN indoor air levels were revealed. However, the weakness of the associations indicates a considerable impact of other MTp sources, e.g. diet and consumer products, on the internal exposure.     

Intake of phthalate-tainted foods and microalbuminuria in children: The 2011 Taiwan food scandal

BackgroundA major threat to public health involving phthalate-tainted foodstuffs occurred in Taiwan in 2011. Phthalates, mainly di-(2-ethylhexyl) phthalate (DEHP), were intentionally added to several categories of food commonly consumed by children. This study investigated the relationship between intake of the phthalate-tainted foods and renal function in children.MethodsChildren aged ≤ 10 years with possible phthalate exposure were enrolled in this study between August 2012 and January 2013. Questionnaires were used to collect details of exposure to phthalate-tainted foodstuffs, and blood and urine samples were collected for clinical biochemical workup. The clinical biomarkers of renal injury, including urinary microalbumin, N-acetyl-beta-d-glucosaminidase (NAG), and β2-microglobulin were measured. Exposure was categorized based on recommended tolerable daily intake level defined by the U.S. Environmental Protection Agency (0.02 mg/kg/day) and the European Food Safety Authority (0.05 mg/kg/day).ResultsWe analyzed intake and renal function of 184 children whose intake of DEHP-tainted foods was known. Higher DEHP exposure to DEHP-tainted foods was significantly associated with increase of urine albumin/creatinine ratio (ACR). Children in the high-exposed group (daily DEHP intake (DDI) > 0.05 mg/kg/day) had 10.395 times the risk of microalbuminuria than the low-exposed group (DDI ≤ 0.02 and > 0 mg/kg/day) and no-exposed group combined after adjustment (95% CI = 1.096–98.580, P = 0.04).ConclusionIntake of DEHP from phthalate-tainted foods may be a potential risk factor for microalbuminuria, a marker of glomerular injury in children.     

Maternal and fetal exposure to parabens in a multiethnic urban U.S. population

Fetal exposure to five parabens was investigated due to their endocrine-disrupting potential and possible impact on fetal development. Body burdens occurring from real-world exposures were determined typically as total concentrations after conjugate hydrolysis in 181 maternal urine and 38 umbilical cord blood plasma samples from a multiethnic cohort of 185 predominantly-black, pregnant women recruited in Brooklyn, New York between 2007/9. For 33 participants, both sample types (maternal urine and cord blood) were available. Methyl- (MePB), ethyl- (EtPB), propyl- (PrPB), butyl- (BuPB), and benzylparaben (BePB) were detected in 100, 73.5, 100, 66.3 and 0.0% of the urine samples at median concentrations of 279, 1.44, 75.3, 0.39, and < 0.02 μg/L, respectively. Median concentrations of MePB and PrPB were, respectively 4.4- and 8.7-fold higher compared to those reported previously for the general U.S. population (NHANES, 2005/6). Listed in the order above, the five parabens were detected in 97.4, 94.7, 47.4, 47.4, and 44.7% of cord blood plasma samples at median total concentrations of 25.0, 0.36, < 0.27, < 0.09, and < 0.10 μg/L, respectively. Free MePB, EtPB, and PrPB were detected in a subset of cord blood plasma samples at, respectively, 3.9, 71.7, and 6.4% of their total concentrations, whereas free BuPB and BePB were not detected. Literature data and those reported here show the urban community studied here to rank highest in the world for MePB and PrPB exposure in pregnant women, whereas it ranks among the lowest for EtPB and BuPB. This study is the first to report the occurrence of parabens in human umbilical cord blood. Maternal exposure to parabens is widespread, and substantial differences were found to exist between communities and countries both in the spectrum and degree of paraben exposures.     

Aggregate dermal exposure to cyclic siloxanes in personal care products: Implications for risk assessment

Consumers who use personal care products (PCPs) are internally exposed to some of the organic components present of which some may be detected in exhaled air when eliminated. The aim of this study was the quantitative determination of octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in end-exhaled air to study dermal absorption of substances in PCPs. We exposed the forearm of fifteen healthy volunteers for 60 min to pure D4 or D5 and to commercial products containing D4 and D5. Inhalation uptake was kept to a minimum by keeping the forearm in a flow cabinet during dermal exposure and supplying filtered air to the breathing zone of the volunteer during the post-exposure period. End-exhaled air was collected using a breath sampler (Bio-VOC), transferred to carbograph multi-bed adsorbent tubes and analyzed by thermal desorption gas chromatography mass spectrometry (TD-GC-MS). In the end-exhaled air of non-exposed volunteers background concentrations of D4 (0.8–3.5 ng/L) and D5 (0.8–4.0 ng/L) were observed. After exposing the volunteers, the level of D4 and D5 in end-exhaled air did not or barely exceed background concentrations. At t = 90 min, a sharp increase of the D4/D5 concentration in end-exhaled air was observed, which we attributed to the inhalation of the substances during a toilet visit without using inhalation protection devices. When this visit was taken out of the protocol, the sharp increase disappeared. Overall, the results of our study indicate that dermal absorption of D4 and D5 contributes only marginally to internal exposure following dermal applications. As in our study inhalation is the primary route of entry for these compounds, we conclude that its risk assessment should focus on this particular exposure route.     

Predictors and long-term reproducibility of urinary phthalate metabolites in middle-aged men and women living in urban Shanghai

Phthalate esters are man-made chemicals commonly used as plasticizers and solvents, and humans may be exposed through ingestion, inhalation, and dermal absorption. Little is known about predictors of phthalate exposure, particularly in Asian countries. Because phthalates are rapidly metabolized and excreted from the body following exposure, it is important to evaluate whether phthalate metabolites measured at a single point in time can reliably rank exposures to phthalates over a period of time. We examined the concentrations and predictors of phthalate metabolite concentrations among 50 middle-aged women and 50 men from two Shanghai cohorts, enrolled in 1997–2000 and 2002–2006, respectively. We assessed the reproducibility of urinary concentrations of phthalate metabolites in three spot samples per participant taken several years apart (mean interval between first and third sample was 7.5 years [women] or 2.9 years [men]), using Spearman's rank correlation coefficients and intra-class correlation coefficients. We detected ten phthalate metabolites in at least 50% of individuals for two or more samples. Participant sex, age, menopausal status, education, income, body mass index, consumption of bottled water, recent intake of medication, and time of day of collection of the urine sample were associated with concentrations of certain phthalate metabolites. The reproducibility of an individual's urinary concentration of phthalate metabolites across several years was low, with all intra-class correlation coefficients and most Spearman rank correlation coefficients ≤ 0.3. Only mono(2-ethylhexyl) phthalate, a metabolite of di(2-ethylhexyl) phthalate, had a Spearman rank correlation coefficient ≥ 0.4 among men, suggesting moderate reproducibility. These findings suggest that a single spot urine sample is not sufficient to rank exposures to phthalates over several years in an adult urban Chinese population.     

Determinants of urinary bisphenol A concentrations in Mexican/Mexican–American pregnant women

Prenatal exposure to bisphenol A (BPA) may be associated with adverse health effects in the developing fetus; however, little is known about predictors of BPA exposure during pregnancy. We examined BPA exposure in 491 pregnant women from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort and explored the role of living in the United States on significant dietary predictors of BPA exposure. Women provided urine samples up to two times during pregnancy (n = 866 total samples). We computed the intraclass correlation coefficient (ICC) to evaluate variability in concentrations between collections and used generalized estimating equation (GEE) models to assess predictors of exposure. Geometric mean (GSD) BPA concentrations were 0.9 (2.8) μg/L and 1.0 (2.6) μg/L at the first and second prenatal visits, respectively. We observed greater within- than between-woman variability in urinary BPA concentrations (ICC = 0.22). GEE models suggest that women who lived in the United States their entire life had 38% (CI: − 0.1, 89.3) higher urinary BPA concentrations compared with other immigrant women. Additionally, women who consumed ≥ 3 sodas per day or hamburgers three times a week or more had 58% (CI: 18.0, 112.1) and 20% (CI: − 0.2, 45.2) higher urinary BPA concentrations, respectively, compared with women who consumed no sodas or hamburgers. A higher percentage of women who lived their entire life in the United States reported increased consumption of sodas and hamburgers compared with other immigrant women. Independent of other factors, BPA urinary concentrations were slightly higher when the sample was collected later in the day. As in previous studies, high within-woman variability in urinary BPA concentrations confirms that several samples are needed to properly characterize exposure during pregnancy. Results also suggest that some factors could be modified to minimize exposures during pregnancy in our study participants (e.g., reducing soda and hamburger intake) and that factors associated with acculturation might increase BPA concentrations.     

Determination of heavy metals in indoor dust from Istanbul,Turkey: Estimation of the health risk

Levels of eight potentially toxic heavy metals in indoor dust from homes and offices in Istanbul were investigated. The concentrations of heavy metals in indoor dust from homes + office ranged from 62 to 1800 μg g^− 1 for Cu, 3–200 μg g^− 1 for Pb, 0.4–20 μg g^− 1 for Cd, 210–2800 μg g^− 1 for Zn, 2.8–460 μg g^− 1 for Cr, 8–1300 μg g^− 1 for Mn, 2.4–25 μg g^− 1 for Co, 120–2600 μg g^− 1 for Ni. Results of the study were comparable to other studies conducted on indoor dust and street dust from a variety of cities globally. Considering only ingestion + inhalation, the carcinogenic risk level of Cr for adults and children (3.7 × 10^− 5 and 2.7 × 10^− 5) in Istanbul was in the range of EPA's safe limits (1 × 10^− 6 and 1 × 10^− 4), indicating that cancer risk of Cr due to exposure to indoor dust in Istanbul can be acceptable. According to calculated Hazard Quotient (HQ), for non-cancer effects, the ingestion of indoor dust appears to be the major route of exposure to the indoor dust that results in a higher risk for heavy metals, followed by dermal contact and inhalation pathways. However, compared to ingestion and dermal contact exposure, exposure through inhalation is almost negligible. Hazard Index (HI) values for all studied elements were lower than safe limit of 1 and this result suggested that none of the population groups would likely to experience potential health risk due to exposure to heavy metals from indoor dust in the study area.