Phthalate and di-(2-ethylhexyl) adipate (DEHA) intake by German infants based on the results of a duplicate diet study and biomonitoring data (INES 2)

Human biomonitoring and toxicokinetics as key building blocks for next generation risk assessment

Human health risk assessment is historically built upon animal testing, often following Organisation for Economic Co-operation and Development (OECD) test guidelines and exposure assessments. Using combinations of human relevant in vitro models, chemical analysis and computational (in silico) approaches bring advantages compared to animal studies. These include a greater focus on the human species and on molecular mechanisms and kinetics, identification of Adverse Outcome Pathways and downstream Key Events as well as the possibility of addressing susceptible populations and additional endpoints. Much of the advancement and progress made in the Next Generation Risk Assessment (NGRA) have been primarily focused on new approach methodologies (NAMs) and physiologically based kinetic (PBK) modelling without incorporating human biomonitoring (HBM). The integration of toxicokinetics (TK) and PBK modelling is an essential component of NGRA. PBK models are essential for describing in quantitative terms the TK processes with a focus on the effective dose at the expected target site. Furthermore, the need for PBK models is amplified by the increasing scientific and regulatory interest in aggregate and cumulative exposure as well as interactions of chemicals in mixtures. Since incorporating HBM data strengthens approaches and reduces uncertainties in risk assessment, here we elaborate on the integrated use of TK, PBK modelling and HBM in chemical risk assessment highlighting opportunities as well as challenges and limitations. Examples are provided where HBM and TK/PBK modelling can be used in both exposure assessment and hazard characterization shifting from external exposure and animal dose/response assays to animal-free, internal exposure-based NGRA.

Analysis of ortho-phthalates and other plasticizers in select organic and conventional foods in the United States

BACKGROUND

ortho-phthalates and other plasticizers impart flexibility to plastics in food production, processing, and packaging; food consumption is a dominant plasticizer exposure pathway. Lower molecular weight ortho-phthalates are being replaced in plastic products due to toxicity concerns, but toxic hazards of and exposures to replacement ortho-phthalates and other plasticizers are poorly understood.

OBJECTIVE

We measured 12 ortho-phthalates and 9 other plasticizers in conventional and organic U.S. food products to assess magnitude and profiles of contamination.

METHODS

We measured plasticizers in 34 vegetable oils, 10 milks, 18 infant formulas, and 9 cheese powders from macaroni kits using gas chromatography coupled with mass spectrometry (GC-MS). We analyzed plastic packaging composition using FTIR spectroscopy.

RESULTS

We detected eight ortho-phthalates and three alternatives ((1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH), diethylhexyl terephthalate (DEHT), and diisobutyl adipate (DIBA). Diethylhexyl phthalate (DEHP) was measured in all 71 products. DEHT had the highest concentration of any plasticizer (>10,000 ng/g in three oils). Oils had the highest total plasticizer (median = 770 ng/g, max = 14,900 ng/g) and milk the lowest (median = 88 ng/g, max = 120 ng/g). Organic milk and refined oils had higher median plasticizer levels than conventional. Refined oils had significantly lower concentrations than unrefined oils. Maximum contributors for every category were non-ortho-phthalates: DEHT (powdered infant formula and oils) and DIBA (cheese powder, milk and liquid formula). Plasticizers were not detected in packaging except epoxidized soybean oil in liquid formula lids.

IMPACT STATEMENT

Human exposure to plasticizers is a significant public health concern. Nevertheless, sources of such exposures are poorly characterized. This study adds valuable information for estimating legacy and alternative plasticizer exposures from foods. The method developed for measuring DINCH, DINP and DIDP broadens the range of plasticizers other researchers may analyze in future work. The profiles of plasticizer contamination varied depending on the food type. We also document that food processing may be a source of plasticizer contamination in foods.

Cumulative Exposure to Phthalates and Their Alternatives and Associated Female Reproductive Health: Body Burdens, Adverse Outcomes, and Underlying Mechanisms

The global birth rate has recently shown a decreasing trend, and exposure to environmental pollutants has been identified as a potential factor affecting female reproductive health. Phthalates have been widely used as plasticizers in plastic containers, children's toys, and medical devices, and their ubiquitous presence and endocrine-disrupting potential have already raised particular concerns. Phthalate exposure has been linked to various adverse health outcomes, including reproductive diseases. Given that many phthalates are gradually being banned, a growing number of phthalate alternatives are becoming popular, such as di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH), di(2-ethylhexyl) adipate (DEHA), and di(2-ethylhexyl) terephthalate (DEHTP), and they are beginning to have a wide range of environmental effects. Studies have shown that many phthalate alternatives may disrupt female reproductive function by altering the estrous cycle, causing ovarian follicular atresia, and prolonging the gestational cycle, which raises growing concerns about their potential health risks. Herein, we summarize the effects of phthalates and their common alternatives in different female models, the exposure levels that influence the reproductive system, and the effects on female reproductive impairment, adverse pregnancy outcomes, and offspring development. Additionally, we scrutinize the effects of phthalates and their alternatives on hormone signaling, oxidative stress, and intracellular signaling to explore the underlying mechanisms of action on female reproductive health, because these chemicals may affect reproductive tissues directly or indirectly through endocrine disruption. Given the declining global trends of female reproductive capacity and the potential ability of phthalates and their alternatives to negatively impact female reproductive health, a more comprehensive study is needed to understand their effects on the human body and their underlying mechanisms. These findings may have an important role in improving female reproductive health and in turn decreasing the number of complications during pregnancy.

Estimated daily intake of phthalates, parabens, and bisphenol A in hospitalised very low birth weight infants

Very low birth weight infants (VLBW, birth weight (BW) < 1500 g) are exposed to phthalates, parabens and bisphenol A (BPA) early in life. We estimated daily intake (EDI) of these excipients in 40 VLBW infants the first and fifth week of life while hospitalised. Based on urinary samples collected in 2010, EDI was calculated and compared to the tolerable daily intake (TDI) with hazard quotients (HQs) evaluated. A HQ > 1 indicates that EDI exceeded TDI with increased risk of adverse health effects. EDI was higher in VLBW infants compared to term-born infants and older children. VLBW infants born at earlier gestational age (GA), or with lower BW, had higher EDI than infants born at later GA or with higher BW. First week median EDI for BPA was higher than TDI in 100% of infants, in 75% for di(2-ethylhexyl) phthalate (DEHP), 90% for the sum of butyl benzyl phthalate (BBzP), di-n-butyl phthalate (DnBP), DEHP and di-iso-nonyl phthalate (DiNP) = ∑BBzP+DnBP+DEHP+DiNP, and in 50% of infants for propylparaben (PrPa), indicating increased risk of adverse effects. Fifth week EDI remained higher than TDI in all infants for BPA, in 75% for DEHP and ∑BBzP+DnBP+DEHP+DiNP, and 25% of infants for PrPa, indicating prolonged risk. Maximum EDI for di-iso-butyl phthalate was higher than TDI suggesting risk of adverse effects at maximum exposure. VLBW infants born earlier than 28 weeks GA had higher EDI, above TDI, for PrPa compared to infants born later than 28 weeks GA. Infants with late-onset septicaemia (LOS) had higher EDI for DEHP, ∑BBzP+DnBP+DEHP+DiNP and BPA, above TDI, compared to infants without LOS. More 75% of the infants' EDI for DEHP and ∑BBzP+DnBP+DEHP+DiNP, 25% for PrPa, and 100% of infants' EDI for BPA, were above TDI resulting in HQs > 1, indicating increased risk of adverse health effects.

The oral bioavailability of di-2-ethylhexyl phthalate (DEHP), di-isononyl phthalate (DiNP) and di-(isononyl)-cyclohexane-1,2-dicarboxylate (DINCH®) in house dust

Phthalates and other plasticizers are detected in high amounts in the indoor environment and therefore house dust can be an exposure source. Especially children have a relatively high unintended uptake of house dust, thus a higher exposure to plasticizers compared to adults may be possible. As accurate as possible exposure assessment data of the oral bioavailability of these compounds are necessary, however only one in vivo study with piglets is available so far. The aim of this study was to examine the oral bioavailability of phthalates and DINCH® in humans, which occur in typical house dust samples. We focused on the high molecular weight phthalates DEHP and DINP and their substitute DINCH®. Eleven volunteers ingested 6 g of house dust sieved to 2 mm. The urine was collected over a period of 36 h. The excreted plasticizers metabolites were quantified by an LC-MS/MS method. The mean recovery of urine metabolites was 51 % ± 20 % for DEHP, 26 % ± 13 % for DINP and 19 % ± 6% for DINCH® based on the parent compounds administered as dust samples. The metabolites of DEHP, DINP and DINCH® reached their maximum concentration after 2-19 hours post dose in urine. The bioavailability of DEHP was in agreement among the different dust samples. For DEHP, we were able to confirm previous findings from the oral bioavailability study with piglets and we could not observe a significant difference between the dust particle size (65 μm vs 2 mm) and the bioavailability. Considering the observed bioavailability, an estimated dust intake of 50 mg/d for toddlers can substantially contribute to the total plasticizer exposure.

Widespread occurrence of phthalate and non-phthalate plasticizers in single-use facemasks collected in the United States

Single-use or disposable facemasks have been widely used by the public for personal protection against the spread of COVID-19. The majority of disposable facemasks are made of synthetic polymers such as polypropylene, polyethylene terephthalate (as polyester), and polystyrene, and could therefore be a source of human exposure to plasticizers that are incorporated into these polymers during production. Little is known, however, about the occurrence of plasticizers in facemasks. In this study, we determined the concentrations of nine phthalate diesters and six non-phthalate plasticizers in 66 facemasks purchased in the United States. Among phthalate diesters, dibutyl phthalate, di(2-ethylhexyl)phthalate, di-iso-butyl phthalate, and butyl benzyl phthalate were found in all facemask samples, at median concentrations of 486, 397, 254, and 92 ng/g, respectively. Among non-phthalate plasticizers, dibutyl sebacate (median: 3390 ng/g) and di(2-ethylhexyl)adipate (352 ng/g) were found at notable concentrations. Inhalation exposure to select phthalate and non-phthalate plasticizers from the use of facemasks was estimated to range from 0.1 to 3.1 and 3.5 to 151 ng/kg-bw/d, respectively. To our knowledge, this is the first study to report the occurrence of phthalate and non-phthalate plasticizers in facemasks collected from the United States.

An integrated exposure and pharmacokinetic modeling framework for assessing population-scale risks of phthalates and their substitutes

To effectively incorporate in vitro-in silico-based methods into the regulation of consumer product safety, a quantitative connection between product phthalate concentrations and in vitro bioactivity data must be established for the general population. We developed, evaluated, and demonstrated a modeling framework that integrates exposure and pharmacokinetic models to convert product phthalate concentrations into population-scale risks for phthalates and their substitutes. A probabilistic exposure model was developed to generate the distribution of multi-route exposures based on product phthalate concentrations, chemical properties, and human activities. Pharmacokinetic models were developed to simulate population toxicokinetics using Bayesian analysis via the Markov chain Monte Carlo method. Both exposure and pharmacokinetic models demonstrated good predictive capability when compared with worldwide studies. The distributions of exposures and pharmacokinetics were integrated to predict the population distributions of internal dosimetry. The predicted distributions showed reasonable agreement with the U.S. biomonitoring surveys of urinary metabolites. The "source-to-outcome" local sensitivity analysis revealed that food contact materials had the greatest impact on body burden for di(2-ethylhexyl) adipate (DEHA), di-2-ethylhexyl phthalate (DEHP), di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH), and di(2-propylheptyl) phthalate (DPHP), whereas the body burden of diethyl phthalate (DEP) was most sensitive to the concentration in personal care products. The upper bounds of predicted plasma concentrations showed no overlap with ToxCast in vitro bioactivity values. Compared with the in vitro-to-in vivo extrapolation (IVIVE) approach, the integrated modeling framework has significant advantages in mapping product phthalate concentrations to multi-route risks, and thus is of great significance for regulatory use with a relatively low input requirement. Further integration with new approach methodologies will facilitate these in vitro-in silico-based risk assessments for a broad range of products containing an equally broad range of chemicals.

Pre- and early post-natal exposure to phthalates and DINCH in a new type of mother-child cohort relying on within-subject pools of repeated urine samples

For non-persistent chemicals such as phthalates, a single spot urine sample only reflects exposure in the past few hours. Collecting repeated urine samples for each participant over windows of sensitivity is expected to improve exposure characterization but has rarely been done. We aimed to rely on within-subject pools of repeated urine samples to assess phthalate exposure during pregnancy and infancy. Women of the French SEPAGES mother-child cohort were asked to collect three urine samples per day over seven consecutive days, twice during their pregnancy (approximatively second (T2) and third (T3) trimesters). For their infants they also collected one sample per day during a week at two (M2) and twelve months (M12). Samples were pooled (within-subject, within-period) prior to phthalate and DINCH metabolite concentrations assessment. Number of pooled samples assayed was 477, 456, 152 and 100 for T2, T3, M2 and M12, respectively. All metabolites were detected in more than 95% of the pooled samples except for the two DINCH metabolites (oh- and oxo-MINCH), MMCHP and oh-MPHP at M2 for which detection frequencies ranged between 64% and 88%. Maternal concentrations of MiBP, MBzP, DEHP metabolites and oxo-MiNP decreased between 2014 and 2017, whereas concentrations of oh-MiNP and the two DINCH metabolites increased (Mann-Kendall p-values < 0.05). While improved compared to studies that relied on spot samples, Intraclass Correlation Coefficients for the pregnancy were below 0.40 for most metabolites. Spearman correlation coefficients between pooled samples collected in infancy were lower than those observed during pregnancy, and were all below 0.30. Exposure to emerging phthalate substitutes such as DINCH and DPHP seems widespread among pregnant women and infants. Collecting repeated urine samples in pregnant women and infants is feasible. The relatively low correlation across trimesters and between maternal and infant samples highlights the need to collect biospecimens in the assumed sensitive time window.

Indoor phthalate exposure and contributions to total intake among pregnant women in the SELMA study

Phthalates are widely used in consumer products. Exposure to phthalates can lead to adverse health effects in humans, with early-life exposure being of particular concern. Phthalate exposure occurs mainly through ingestion, inhalation, and dermal absorption. However, our understanding of the relative importance of different exposure routes is incomplete. This study estimated the intake of five phthalates from the residential indoor environment for 455 Swedish pregnant women in the SELMA study using phthalate mass fraction in indoor dust and compares these to total daily phthalate intakes back-calculated from phthalate metabolite concentrations in the women's urine. Steady-state models were used to estimate indoor air phthalate concentrations from dust measurements. Intakes from residential dust and air made meaningful contributions to total daily intakes of more volatile di-ethyl phthalate (DEP), di-n-butyl phthalate (DnBP), and di-iso-butyl phthalate (DiBP) (11% of total DEP intake and 28% of total DnBP and DiBP intake combined). Dermal absorption from air was the dominant pathway contributing to the indoor environmental exposure. Residential exposure to less volatile phthalates made minor contributions to total intake. These results suggest that reducing the presence of low molecular weight phthalates in the residential indoor environment can meaningfully reduce phthalate intake among pregnant women.

Di(2-ethylhexyl) adipate plasticizer triggers hepatic, brain, and cardiac injury in rats: Mitigating effect of Peganum harmala oil

Di(2-ethylhexyl) adipate (DEHA) is a widely used plasticizer and prevalent environmental contaminant. In this study, DEHA concentrations in the milk, cheese, and butter samples wrapped with food-grade commercial polyethylene films and stored at 4 °C for 30 days were detected using gas chromatographic analysis. Also, the effects of exposure to a high dose of DEHA for a long duration on the liver, brain, and heart of Wistar rats were assessed. Besides, the possible beneficial effect of Peganum harmala oil (PGO), in relieving DEHA induced adverse effects was explored. For this purpose, four groups (8 rats/group) were orally given physiological saline, PGO (320 mg/kg bwt), DEHA (2000 mg/kg bwt), or PGO + DEHA for 60 days. The results revealed that the DEHA concentrations in the tested dairy products were ordered as follows: (butter > cheese > milk). Notably, the detected levels in butter were higher than the specific migration limit in foods. DEHA induced a significant increase in the serum levels of glucose, alanine transaminase, aspartate transaminase, acetylcholine esterase, creatine kinase-myocardium bound, malondialdehyde, tumor necrosis factor-α, and interleukin-1β. But, significant hypoproteinemia, hypoalbuminemia, hypoglobulinemia, and hypocholesterolemia were evident following DEHA exposure. A significant reduction in the serum level of superoxide dismutase, reduced glutathione, and brain-derived neurotrophic factor was recorded. Besides, a significant downregulation in hepatic CYP2E1, brain glial fibrillary acidic protein, and cardiac troponin I gene expression was noticed. Moreover, DEHA exposure induced a significant decrease in Bcl-2 immunolabeling, but Caspase-3 immunoexpression was increased. On the contrary, PGO significantly recused DEHA injurious impacts. Therefore, PGO could represent a promising agent for preventing DEHA-induced hepatotoxicity, neurotoxicity, and cardiotoxicity.

Risk assessment for humans using physiologically based pharmacokinetic model of diethyl phthalate and its major metabolite, monoethyl phthalate

Diethyl phthalate (DEP) belongs to phthalates with short alkyl chains. It is a substance frequently used to make various products. Thus, humans are widely exposed to DEP from the surrounding environment such as food, soil, air, and water. As previously reported in many studies, DEP is an endocrine disruptor with reproductive toxicity. Monoethyl phthalate (MEP), a major metabolite of DEP in vivo, is a biomarker for DEP exposure assessment. It is also an endocrine disruptor with reproductive toxicity, similar to DEP. However, toxicokinetic studies on both MEP and DEP have not been reported in detail yet. Therefore, the objective of this study was to evaluate and develop physiologically based pharmacokinetic (PBPK) model for both DEP and MEP in rats and extend this to human risk assessment based on human exposure. This study was conducted in vivo after intravenous or oral administration of DEP into female (2 mg/kg dose) and male (0.1-10 mg/kg dose) rats. Biological samples consisted of urine, plasma, and 11 different tissues. These samples were analyzed using UPLC-ESI-MS/MS method. For DEP, the tissue to plasma partition coefficient was the highest in the kidney, followed by that in the liver. For MEP, the tissue to plasma partition coefficient was the highest in the liver. It was less than unity in all other tissues. Plasma, urine, and fecal samples were also obtained after IV administration of MEP (10 mg/kg dose) to male rats. All results were reflected in a model developed in this study, including in vivo conversion from DEP to MEP. Predicted concentrations of DEP and MEP in rat urine, plasma, and tissue samples using the developed PBPK model fitted well with observed values. We then extrapolated the PBPK model in rats to a human PBPK model of DEP and MEP based on human physiological parameters. Reference dose of 0.63 mg/kg/day (or 0.18 mg/kg/day) for DEP and external doses of 0.246 μg/kg/day (pregnant), 0.193 μg/kg/day (fetus), 1.005-1.253 μg/kg/day (adults), 0.356-0.376 μg/kg/day (adolescents), and 0.595-0.603 μg/kg/day (children) for DEP for human risk assessment were estimated using Korean biomonitoring values. Our study provides valuable insight into human health risk assessment regarding DEP exposure.

Urinary levels of phthalates and DINCH metabolites in Korean and Thai pregnant women across three trimesters

Phthalates are anti-androgenic chemicals and may cause long-lasting adverse effects on growing fetuses. Understanding their exposure profile during pregnancy, therefore, is of public health importance. Because both behavioral and physiological changes of pregnant women are expected to be substantial, the amount of phthalate exposure is expected to vary significantly over the course of pregnancy. Temporal trend of phthalate exposure during pregnancy, however, is largely unknown, especially in Asian women. The purpose of this study is to investigate the urinary concentrations of metabolites for major phthalates and alternative plasticizers over the course of pregnancy among Korean (n = 81) and Thai women (n = 102). Twenty-four metabolites from 15 plasticizers, such as dimethyl phthalate (DMP), diethyl phthalate (DEP), di-isobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), benzyl butyl phthalate (BBzP), di(2-ethylhexyl) phthalate (DEHP), dioctyl phthalate (DnOP), diisononyl phthalate (DiNP), diisodecyl phthalate (DiDP), di(2-ethylhexyl) terephthalate (DEHTP), and di-(iso-nonyl)-cyclohexane-1,2-dicarboxylate (DINCH), were measured in urine samples collected in each trimester from pregnant women. While the levels of several phthalate metabolites were significantly different by trimester among Korean women, those of Thai women were relatively consistent. Urinary metabolites of DEP and DnOP were higher in Thai pregnant women compared to Korean pregnant women. The detection frequencies of the DINCH metabolite were 67.4% and 44.9% among Korean and Thai pregnant women, respectively. However, the ratio of DINCH to DEHP metabolites was significantly higher in Thai women. According to risk assessment, 11.9% of Korean and 5.3% of Thai women were considered at risk due to phthalate exposure, and DEHP, DnBP and DiBP were identified as major risk drivers. Considering the vulnerability of growing fetuses, further studies are warranted to identify major sources of exposure to these plasticizers during pregnancy.

Update of the risk assessment of di-butylphthalate (DBP), butyl-benzyl-phthalate (BBP), bis(2-ethylhexyl)phthalate (DEHP), di-isononylphthalate (DINP) and di-isodecylphthalate (DIDP) for use in food contact materials

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP Panel) was asked by the European Commission to update its 2005 risk assessments of di-butylphthalate (DBP), butyl-benzyl-phthalate (BBP), bis(2-ethylhexyl)phthalate (DEHP), di-isononylphthalate (DINP) and di-isodecylphthalate (DIDP), which are authorised for use in plastic food contact material (FCM). Dietary exposure estimates (mean and high (P95)) were obtained by combining literature occurrence data with consumption data from the EFSA Comprehensive Database. The highest exposure was found for DINP, ranging from 0.2 to 4.3 and from 0.4 to 7.0 μg/kg body weight (bw) per day for mean and high consumers, respectively. There was not enough information to draw conclusions on how much migration from plastic FCM contributes to dietary exposure to phthalates. The review of the toxicological data focused mainly on reproductive effects. The CEP Panel derived the same critical effects and individual tolerable daily intakes (TDIs) (mg/kg bw per day) as in 2005 for all the phthalates, i.e. reproductive effects for DBP (0.01), BBP (0.5), DEHP (0.05), and liver effects for DINP and DIDP (0.15 each). Based on a plausible common mechanism (i.e. reduction in fetal testosterone) underlying the reproductive effects of DEHP, DBP and BBP, the Panel considered it appropriate to establish a group-TDI for these phthalates, taking DEHP as index compound as a basis for introducing relative potency factors. The Panel noted that DINP also affected fetal testosterone levels at doses around threefold higher than liver effects and therefore considered it conservative to include it within the group-TDI which was established to be 50 μg/kg bw per day, expressed as DEHP equivalents. The aggregated dietary exposure for DBP, BBP, DEHP and DINP was estimated to be 0.9-7.2 and 1.6-11.7 μg/kg bw per day for mean and high consumers, respectively, thus contributing up to 23% of the group-TDI in the worst-case scenario. For DIDP, not included in the group-TDI, dietary exposure was estimated to be always below 0.1 μg/kg bw per day and therefore far below the TDI of 150 μg/kg bw per day. This assessment covers European consumers of any age, including the most sensitive groups. Based on the limited scope of the mandate and the uncertainties identified, the Panel considered that the current assessment of the five phthalates, individually and collectively, should be on a temporary basis.

Bioavailability of phthalate and DINCH® plasticizers, after oral administration of dust to piglets

For decades, phthalates have been widely used as plasticizers in a large number of consumer products, leading to a complex exposure to humans via ingestion, inhalation or dermal uptake. Children may have a higher unintended dust intake per day compared to adults. Therefore, dust intake of children could pose a relevant exposure and subsequently a potential health risk. The aim of this study was to determine the relative bioavailability of certain phthalates, such as di(2-ethylhexyl) phthalate (DEHP), di-isononyl phthalate (DINP) and the non-phthalate plasticizer diisononyl 1,2-cyclohexanedicarboxylic acid (DINCH^®, Hexamoll^®), after ingestion of dust. Seven 5-week-old male piglets were fed five different dust samples collected from daycare centers. Overall, 0.43 g to 0.83 g of dust sieved to 63 μm were administered orally. The piglets' urine was collected over a period of 38 h. The excreted metabolites were quantified using an LC-MS/MS method. The mean uptake rates of the applied doses for DEHP, DINP, and DINCH^® were 43% ± 11%, 47% ± 26%, and 9% ± 3.5%, respectively. The metabolites of DEHP and DINP showed maximum concentrations in urine after three to five hours, whereas the metabolites of DINCH^®, reached maximum concentrations 24 h post-dose. The oral bioavailability of the investigated plasticizers was higher compared to the bioaccessibility reported from in vitro digestion tests. Furthermore, the bioavailability of DEHP did not vary substantially between the dust samples, whereas a dose-dependent saturation process for DINP was observed. In addition to other intake pathways, dust could be a source of plasticizers in children using the recent intake rates for dust ingestion.

Is the Cooking Salt Safe in China? Assessment of Chemical Contaminants in Cooking Salt

Global environmental pollution is becoming more serious, and most dietary salts come from nature. We postulated that chemical pollutants could affect the quality of salt. Forty-five different types of salt were collected from supermarkets, convenience stores, and online retailers in Shanghai, 2015. These comprised more than 90% of all cooking salts consumed in Shanghai, China. We measured and analyzed heavy metal elements, fluoride, potassium ferrocyanide, and 16 phthalate plasticizers. Lead was detected in only two types of salt at concentrations recorded of 0.047 mg/kg and 0.077 mg/kg. The concentrations of total arsenic, total mercury, cadmium, and barium were under limit of detection (LOD) in all samples. The maximum fluoride concentration of salts was 2.50 mg/kg. The median fluoride concentration of domestic salts was significantly lower than foreign-produced salts, and it was significantly higher in sea salt than in other types of salt (P < 0.05). The maximum potassium ferrocyanide concentration in 12 types of salts was 9.20 mg/kg, which was under the Chinese national standard. Just three salt types had low levels of diethylhexyl phthalate concentrations that were above the LOD, at 0.208 mg/kg, 0.375 mg/kg, and 0.380 mg/kg, respectively. All other phthalate indicators were below the LOD in all samples. The level of chemical pollutants in salt is either very low or under LOD. We believe that dietary salt products are safe at retail, and the long-term dietary exposure of cooking salts will not pose any significant health risk.

Urinary phthalate metabolites over the first 15months of life and risk assessment - CHECK cohort study

Phthalates are important group of endocrine disruptors. Infants and young children are susceptible to phthalate exposure. However, information on the phthalate exposure during the early stages of life is very limited. This study was conducted to understand the temporal trend of exposure to major phthalates among infants of Korea during the first 15months after birth, and to estimate associated risks. A total of 286 urine samples were collected from 171 children at 3, 9, 12, or 15months of age, with 77 children sampled for two or more times. Four phthalates, i.e., di(2-ethylhexyl) phthalate (DEHP), di-isobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and diethyl phthalate (DEP) were chosen, and their major metabolites were analyzed in the urine. The DEHP metabolites were detected in 100% of the urine samples at relatively higher levels compared to those reported in other countries. The levels of mono-ethyl phthalate (MEP) were generally lower. Urinary concentrations of most phthalate metabolites, especially DEHP metabolites, increased as children grew older. Intra-class correlation coefficients (ICCs) calculated for DEHP metabolites over time were high (0.7-0.8), suggesting persistence of consistent exposure sources during this sensitive period of life. Hazard quotient (HQ) and hazard index (HI) were calculated from daily intake estimates divided by recommended toxicity thresholds. Among the study population, 4, 16, and 26% of the children showed HI >1 at 9, 12, and 15months of age, respectively. DEHP exposure explained most of the risk estimates. Considering vulnerability of young children to endocrine disruption, efforts to identify sources of exposure and to develop appropriate mitigation options are warranted.

Case Study on Screening Emerging Pollutants in Urine and Nails

Alternative plasticizers and flame retardants (FRs) have been introduced as replacements for banned or restricted chemicals, but much is still unknown about their metabolism and occurrence in humans. We identified the metabolites formed in vitro for four alternative plasticizers (acetyltributyl citrate (ATBC), bis(2-propylheptyl) phthalate (DPHP), bis(2-ethylhexyl) terephthalate (DEHTP), bis(2-ethylhexyl) adipate (DEHA)), and one FR (2,2-bis (chloromethyl)-propane-1,3-diyltetrakis(2-chloroethyl) bisphosphate (V6)). Further, these compounds and their metabolites were investigated by LC/ESI-Orbitrap-MS in urine and finger nails collected from a Norwegian cohort. Primary and secondary ATBC metabolites had detection frequencies (% DF) in finger nails ranging from 46 to 95%. V6 was identified for the first time in finger nails, suggesting that this matrix may also indicate past exposure to FRs as well as alternative plasticizers. Two isomeric forms of DEHTP primary metabolite were highly detected in urine (97% DF) and identified in finger nails, while no DPHP metabolites were detected in vivo. Primary and secondary DEHA metabolites were identified in both matrices, and the relative proportion of the secondary metabolites was higher in urine than in finger nails; the opposite was observed for the primary metabolites. As many of the metabolites present in in vitro extracts were further identified in vivo in urine and finger nail samples, this suggests that in vitro assays can reliably mimic the in vivo processes. Finger nails may be a useful noninvasive matrix for human biomonitoring of specific organic contaminants, but further validation is needed.

Effects of six priority controlled phthalate esters with long-term low-dose integrated exposure on male reproductive toxicity in rats

Human beings are inevitably exposed to ubiquitous phthalate esters (PEs) surroundings. The purposes of this study were to investigate the effects of long-term low-dose exposure to the mixture of six priority controlled phthalate esters (MIXPs): dimethyl phthalate (DMP), diethyl phthalate (DEP), di(n-butyl) phthalate (DBP), butyl benzyl phthalate (BBP), di(2-ethyhexyl) phthalate (DEHP) and di-n-octyl phthalate (DNOP), on male rat reproductive system and further to explore the underlying mechanisms of the reproductive toxicity. The male rats were orally exposed to either sodium carboxymethyl cellulose as controls or MIXPs at three different low-doses by gavage for 15 weeks. Testosterone and luteinizing hormone (LH) in serum were analyzed, and pathological examinations were performed for toxicity evaluation. Steroidogenic proteins (StAR, P450scc, CYP17A1 and 17β-HSD), cell cycle and apoptosis-related proteins (p53, Chk1, Cdc2, CDK6, Bcl-2 and Bax) were measured for mechanisms exploration. MIXPs with long-term low-dose exposure could cause male reproductive toxicity to the rats, including the decrease of both serum and testicular testosterone, and the constructional damage of testis. These effects were related to down-regulated steroidogenic proteins, arresting cell cycle progression and promoting apoptosis in rat testicular cells. The results indicate that MIXPs with long-term low-dose exposure may pose male reproductive toxicity in human.

Human exposure, hazard and risk of alternative plasticizers to phthalate esters

Alternative plasticizers to phthalate esters have been used for over a decade, but data regarding emissions, human exposure and health effects are limited. Here we review 20 alternative plasticizers in current use and their human exposure, hazard and risk. Physicochemical properties are collated for these diverse alternatives and log KOW values range over 15 orders of magnitude and log KAW and log KOA values over about 9 orders of magnitude. Most substances are hydrophobic with low volatility and are produced in high volumes for use in multiple applications. There is an increasing trend in the total use of alternative plasticizers in Sweden compared to common phthalate esters in the last 10 years, especially for DINCH. Evaluative indoor fate modeling reveals that most alternatives are distributed to vertical surfaces (e.g. walls or ceilings). Only TXIB and GTA are predicted to be predominantly distributed to indoor air. Human exposure data are lacking and clear evidence for human exposure only exists for DEHT and DINCH, which show increasing trends in body burdens. Human intake rates are collected and compared with limit values with resulting risk ratios below 1 except for infant's exposure to ESBO. PBT properties of the alternatives indicate mostly no reasons for concern, except that TEHPA is estimated to be persistent and TCP toxic. A caveat is that non-standard toxicological endpoint results are not available and, similar to phthalate esters, the alternatives are likely "pseudo-persistent". Key data gaps for more comprehensive risk assessment are identified and include: analytical methods to measure metabolites in biological fluids and tissues, toxicological information regarding non-standard endpoints such as endocrine disruption and a further refined exposure assessment in order to consider high risk groups such as infants, toddlers and children.

Estimated daily intake and cumulative risk assessment of phthalate diesters in a Belgian general population

The daily intakes (DI) were estimated in a Belgian general population for 5 phthalates, namely diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), di-iso-butyl phthalate (DiBP), butylbenzyl phthalate (BBzP) and di-2-ethylhexyl phthalate (DEHP), based on the urinary measurements of their corresponding metabolites. DI values ranged between <LOD and 59.65 μg/kg bw/day depending on the congener, and were globally higher for children than adults. They were compared to acceptable levels of exposure (tolerable daily intakes) to evaluate the hazard quotients (HQ), which highlight an intake above the dose considered as safe for values greater than 1. If very few of our Belgian participants exceeded this threshold for phthalates considered individually, 6.2% of the adults and 25% of the children showed an excessive hazard index (HI) which took into account the cumulative risk of adverse anti-androgenic effects. These results are of concern since these HI were based on only 3 phthalates (DEHP, DiBP and DnBP), and showed a median of 0.55 and 0.29 for children and adults respectively. The comparison with previously determined dietary intakes demonstrated that for DEHP, food intake was nearly the only route of exposure while other pathways occurred mainly for the other studied phthalates.

Analytical methods for the determination of DEHP plasticizer alternatives present in medical devices: a review

Until 2010, diethylhexylphthalate (DEHP) was the plasticizer most commonly used to soften PVC medical devices (MDs), because of a good efficiency/cost ratio. In flexible plasticized PVC, phthalates are not chemically bound to PVC and they are released into the environment and thus may come into contact with patients. The European Directive 2007/47/CE, classified DEHP as a product with a toxicity risk and restricted its use in MDs. MD manufacturers were therefore forced to quickly find alternatives to DEHP to maintain the elasticity of PVC nutrition tubings, infusion sets and hemodialysis lines. Several replacement plasticizers, so-called "alternative to DEHP plasticizers" were incorporated into the MDs. Nowadays, the risk of exposure to these compounds for hospitalized patients, particularly in situations classified "at risk", has not yet been evaluated, because migrations studies, providing sufficient exposure and human toxicity data have not been performed. To assess the risk to patients of DEHP plasticizer alternatives, reliable analytical methods must be first developed in order to generate data that supports clinical studies being conducted in this area. After a brief introduction of the characteristics and toxicity of the selected plasticizers used currently in MDs, this review outlines recently analytical methods available to determine and quantify these plasticizers in several matrices, allowing the evaluation of potential risk and so risk management.

Phthalate intake by infants calculated from biomonitoring data

Urine samples (n=207) of 47 infants between 1- and 5-month of age were quantitated for 12 metabolites of 7 phthalates and compared with samples collected from the mothers of the infants at different time points. Median and 95-percentile were lower for all metabolites in urine samples of infants compared to mothers. For di-2-ethylhexyl phthalate (DEHP) the 95-percentile daily intake was 23.3μg/kg b.w. for mothers and 5.4μg/kg b.w. for infants and for di-isobutyl phthalate (DiBP) 10.1μg/kg b.w. and 8.5μg/kg b.w. Some values exceeded the corresponding tolerable daily intake (TDI) for DiBP for infants and mothers and for DEHP and di-n-butyl phthalate (DnBP) only for mothers. Both, infants and mothers are able to efficiently form phase II metabolites but infants with a slightly lower degree. Therefore, a distinguished risk assessment with respect to the formed toxic metabolites of phthalates would be necessary in combination with a reduction of the most toxic phthalates.

Mammalian toxicology and human exposures to the flame retardant 2,2',6,6'-tetrabromo-4,4'-isopropylidenediphenol (TBBPA): implications for risk assessment

The compound 2,2',6,6'-Tetrabromo-4,4'-isopropylidenediphenol (tetrabromobisphenol A, TBBPA) is used as a reactive and additive flame retardant. This review evaluates the mammalian toxicology of TBBPA and summarizes recent human exposure and risk assessments. TBBPA has a low potential for systemic or reproductive toxicity, and no-observed-adverse-effect-levels were greater than 1,000 mg/kg body weight (bw)/day in a 90-day oral toxicity study, a developmental toxicity study and a two-generation reproductive and developmental toxicity study. Some interactions of TBBPA with hormone-mediated pathways were noted in vitro; however, when studied in vivo, TBBPA did not produce adverse effects that might be considered to be related to disturbances in the endocrine system. Therefore, in accordance with internationally accepted definitions, TBBPA should not be considered an "endocrine disruptor." Furthermore, TBBPA is rapidly excreted in mammals and therefore does not have a potential for bioaccumulation. Measured concentrations of TBBPA in house dust, human diet and human serum samples are very low. Daily intakes of TBBPA in humans were estimated to not exceed a few ng/kg bw/day. Due to the low exposures and the low potential for toxicity, margins of exposures for TBBPA in the human population were between 6 × 10(4) (infants) to 6 × 10(7) (adults). Exposures of the general population are also well below the derived-no-effect-levels derived for endpoints of potential concern in REACH.

Phthalates in German daycare centers: occurrence in air and dust and the excretion of their metabolites by children (LUPE 3)

Phthalates have been used for decades in large quantities, leading to the ubiquitous exposure of the population. In an investigation of 63 German daycare centers, indoor air and dust samples were analyzed for the presence of 10 phthalate diesters. Moreover, 10 primary and secondary phthalate metabolites were quantified in urine samples from 663 children attending these facilities. In addition, the urine specimens of 150 children were collected after the weekend and before they went to daycare centers. Di-isobutyl phthalate (DiBP), dibutyl phthalate (DnBP), and di-2-ethylhexyl phthalate (DEHP) were found in the indoor air, with median values of 468, 227, and 194ng/m(3), respectively. In the dust, median values of 888mg/kg for DEHP and 302mg/kg for di-isononyl phthalate (DiNP) were observed. DnBP and DiBP were together responsible for 55% of the total phthalate concentration in the indoor air, whereas DEHP and DiNP were responsible for 70% and 24% of the total phthalate concentration in the dust. Median concentrations in the urine specimens were 44.7μg/l for the DiBP monoester, 32.4μg/l for the DnBP monoester, and 16.5μg/l and 17.9μg/l for the two secondary DEHP metabolites. For some phthalates, we observed significant correlations between their concentrations in the indoor air and dust and their corresponding metabolites in the urine specimens using bivariate analyses. In multivariate analyses, the concentrations in dust were not associated with urinary metabolite excretion after controlling for the concentrations in the indoor air. The total daily "high" intake levels based on the 95th percentiles calculated from the biomonitoring data were 14.1μg/kg b.w. for DiNP and 11.9μg/kg b.w. for DEHP. Compared with tolerable daily intake (TDI) values, our "high" intake was 62% of the TDI value for DiBP, 49% for DnBP, 24% for DEHP, and 9% for DiNP. For DiBP, the total daily intake exceeded the TDI value for 2.4% of the individuals. Using a cumulative risk-assessment approach for the sum of DEHP, DnBP, and DiBP, 20% of the children had concentrations exceeding the hazard index of one. Therefore, a further reduction of the phthalate exposure of children is needed.