Phthalates and alternative plasticizers and potential for contact exposure from children's backpacks and toys

Bioaccessibility of plastic-related compounds from polymeric particles in marine settings: Are microplastics the principal vector of phthalate ester congeners and bisphenol A towards marine vertebrates?

Marine vertebrates are known to ingest significant amounts of microplastics (MPs). Once ingested, MPs might cause gastrointestinal injuries and serve as a path of harmful plastic components, such as phthalate esters (PAEs) and bisphenol A (BPA) in the food chain. However, there is a lack of standardized in-vitro methods capable of simulating fish uptake of chemicals from MPs in the environment as potential vectors of such contaminants. In this work, leaching and in-vitro oral bioaccessibility testing of PAEs and BPA from MPs were conducted batchwise using artificial seawater and gut fluids mimicking gastric, intestinal, and gastrointestinal compartments of marine vertebrates at physiological temperature. The environmental and physiologically relevant extraction tests were applied to medium-density polyethylene (PE) and polyvinyl chloride (PVC) certified reference materials containing eight PAEs of varying hydrophobicity, namely, dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate, benzylbutyl phthalate, diethylhexyl phthalate, di-n-octyl phthalate, diisononyl phthalate and diisodecyl phthalate, and BPA (only in PE) as MP surrogates with realistic analyte concentrations of additives for primary MPs. The analysis of the leachates/gut fluid extracts was performed via dilute-and-shoot by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Only the most hydrophilic compounds, i.e. DMP, DEP and BPA, were found to get released significantly in saline waters, and exhibited the highest oral bioaccessibility rates (34-83 %). Based on our results, a dual-compartment physiologically relevant gastrointestinal test is recommended for appropriate estimation of fish bioaccessibility. The fish daily intakes of DMP, DEP and BPA from MPs, and seawater ingestion as well were estimated using several contamination scenarios (10th percentile as the low level, 50th percentile as the medium level and 90th percentile as the high level) based on probabilistic distributions and cumulative probability curves of measured environmental concentrations of (i) MPs in seawater throughout the world, (ii) DMP, DEP and BPA in beached MPs and those sampled in the open ocean (including both incurred and adsorbed contaminants), and (iii) DMP, DEP and BPA in seawater as reported in recent literature. Under a medium-level concentration scenario (50th percentile) in marine settings, and taking the gastrointestinal bioaccessibility factor into account, the daily intake of DMP, DEP and BPA from MPs accounted for a mere 0.02 % of the waterborne contribution. Hence, the ingestion of MPs should not be considered the primary route of fish exposure to BPA and the most polar PAEs in marine environments. However, more studies on the local and the global scales for mass concentrations of MPs and additives in marine settings are needed for further confirmation of our findings.

Assessment of biodegradation and toxicity of alternative plasticizer di(2-ethylhexyl) terephthalate: Impacts on microbial biofilms, metabolism, and reactive oxygen species-mediated stress response

Although di(2-ethylhexyl) terephthalate (DOTP) is being widely adopted as a non-phthalate plasticizer, existing research primarily focuses on human and rat toxicity. This leaves a significant gap in our understanding of their impact on microbial communities. This study assessed the biodegradation and toxicity of DOTP on microbes, focusing on its impact on biofilms and microbial metabolism using Rhodococcus ruber as a representative bacterial strain. DOTP is commonly found in mass fractions between 0.6 and 20% v/v in various soft plastic products. This study used polyvinyl chloride films (PVC) with varying DOTP concentrations (range 1-10% v/v) as a surface for analysis of biofilm growth. Cell viability and bacterial stress responses were tested using LIVE/DEAD™ BacLight™ Bacterial Viability Kit and by the detection of reactive oxygen species using CellROX™ Green Reagent, respectively. An increase in the volume of dead cells (in the plastisphere biofilm) was observed with increasing DOTP concentrations in experiments using PVC films, indicating the potential negative impact of DOTP on microbial communities. Even at a relatively low concentration of DOTP (1%), signs of stress in the microbes were noticed, while concentrations above 5% compromised their ability to survive. This research provides a new understanding of the environmental impacts of alternative plasticizers, prompting the need for additional research into their wider effects on both the environment and human health.

Phthalate esters in clothing: A review

Phthalate esters (PAEs) are widely used as plasticizers to enhance the flexibility and durability of different consumer products, including clothing. However, concerns have been raised about the potential adverse health effects associated with the presence of phthalates in textiles, such as endocrine disruption, reproductive toxicity and potential carcinogenicity. Based on examination of more than 120 published articles, this paper presents a comprehensive review of studies concerning the phthalate content in clothing and other textile products, with special emphasis on those conducted in the last decade (2014-2023). The types and role of PAEs as plasticizers, the relevant legislation in different countries (emphasizing the importance of monitoring PAE levels in clothing to protect consumer health) and the analytical methods used for PAE determination are critically evaluated. The review also discusses the models used to evaluate exposure to PAEs and the associated health risks. Finally, the study limitations and challenges related to determining the phthalate contents of textile products are considered.

Formation kinetics of SVOC organic films and their impact on child exposure in indoor environments

We conducted an SVOC mass transfer and child-exposure modeling analysis considering the combined sorption of multiple SVOCs containing DnBP, BBP, DEHP, DINP and DINCH in indoor environments. A mechanistic model was applied to describe the organic film formation, and a partition-coefficient-prediction model was originally developed for the realistic organic films. The characteristics of film formation on impermeable surfaces were examined based on three different assumptions: the widely-used constant Kns,im assumption, Koa assumption, and the proposed Kom assumption (predicted specifically for the realistic organic films in this study). After long-term SVOC sorption, the organic film reached increasing equilibrium gradually under constant Kns,im assumption. While under Koa and Kom assumption, organic films exhibited nearly linear increases on surfaces, the trends of which agreed well with field studies. However, the film thicknesses calculated under Kom assumption with larger film partition coefficients were approximately twice larger than those under Koa assumption. Meanwhile, Horizontal surfaces with higher deposition rates of particle-phase SVOCs exhibited larger velocities of film growth compared to vertical surfaces. Under the Kom assumption, exposures of hazardous SVOCs for a 3-year-old child increased by 87.5 %-198.7 % even with the weekly cleaning of indoor impermeable surfaces, carpet and cloth. This study is anticipated to provide valuable insights into the film-forming characteristics of multiple SVOCs and the accompanying significant health risks to human beings in indoor environments.

Association between urinary phthalate metabolites and chronic obstructive pulmonary disease incidence in US adults: results from NHANES 2007-2018

Despite associations between urinary phthalates and respiratory symptoms and disorders have been investigated, knowledge about their impact on COPD incidence remains limited. Using data of 8242 adults (aged 20-80 years) from the 2007-2018 National Health and Nutrition Examination Survey (NHANES), the association of mixed urinary phthalate metabolites with COPD incidence was evaluated. Among them, 789 were COPD patients, and the rest were non-COPD participants. In the single-pollutant models, a variety of phthalate metabolites were identified as independent positive factors for COPD incidence, including mono-(carboxynonyl) phthalate (MCNP), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono-n-butyl phthalate (MnBP), mono-(3-carboxylpropyl) phthalate (MCPP), mono-ethyl phthalate (MEP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-benzyl phthalate (MBzP). Multi-pollutant models, including weighted quantile sum (WQS) regression, quantile-based g computation (qgcomp), and Bayesian kernel machine regression (BKMR) approaches consistently revealed the positive association between phthalates co-exposure and COPD incidence, and MCPP was recognized as the dominant positive driver. The positive association was more evident in the youth group and the male group. The interactions between certain phthalate metabolites in COPD were also observed. Given the limitations of the cross-sectional design of NHANES study, well-designed longitudinal studies are needed to verify or disprove these findings.

Characteristics and health risks of population exposure to phthalates via the use of face towels

The production of face towels is growing at an annual rate of about 4% in China, reaching 1.13 million tons by 2021. Phthalates (PAEs) are widely used in textiles, and face towels, as an important household textile, may expose people to PAEs via the skin, further leading to health risks. We collected new face towels and analyzed the distribution characterization of PAEs in them. The changes of PAEs were explored in a face towel use experiment and a simulated laundry experiment. Based on the use of face towels by 24 volunteers, we calculated the estimated daily intake (EDI) and comprehensively assessed the hazard quotient (HQ), hazard index (HI), and dermal cancer risk (DCR) of PAEs exposure in the population. PAEs were present in new face towels at total concentrations of <MDL-2388 ng/g, with a median of 173.2 ng/g, which was a lower contamination level compared with other textiles. PAE contents in used face towels were significantly higher than in new face towels. The concentrations of PAEs in coral velvet were significantly higher than those in cotton. Water washing removed some PAEs, while detergent washing increased the PAE content on face towels. Gender, weight, use time, and material were the main factors affecting EDI. The HQ and HI were less than 1, which proved PAEs had no significant non-carcinogenic health risks. Among the five target PAEs studied, DEHP was the only carcinogenic PAE and may cause potential health risks after long-term exposure. Therefore, we should pay more attention to DEHP.

Enhanced migration of plasticizers from polyvinyl chloride consumer products through artificial sebum

In the present study, the migration of plasticizers from modeled and commercial polyvinyl chloride (mPVC and cPVC, respectively) to poly(dimethylsiloxane) via artificial sebum was assessed to mimic the dermal migration of plasticizers. In addition, the various factors affecting migration of phthalic acid esters (PAEs) from diverse PVC products were investigated. The migrated mass and migration ratio of PAEs increased but the migration rate decreased over time. The migration rate increased with sebum mass, contact time, and temperature but decreased under higher pressure. Low-molecular-weight PAEs (dimethyl phthalate and diethyl phthalate) migrated in higher amounts than high-molecular-weight PAEs (dicyclohexyl phthalate [DCHP] and diisononyl phthalate [DINP]). Diffusion of all PAEs in mPVC increased with temperature, with diffusion coefficients ranging from 10^-13 to 10^-15, 10^-12 to 10^-14, and 10^-10 to 10^-12 cm²·s^-1 at 25 °C, 40 °C, and 60 °C, respectively; the enthalpy of activation ranged between 127 and 194 kJ·mol^-1. Moreover, migration depended on total PAE content of the product, as the diffusion coefficient for DINP in cPVC (softer PVC) was approximately three orders of magnitude higher than that for DINP in mPVC (harder PVC); this may be due to the increase in free volume with increasing plasticizer content. Finally, the daily exposure doses of the plasticizers were estimated. These findings will be helpful for estimating dermal exposure risk.

A rapid micro chamber method to measure SVOC emission and transport model parameters

Assessing exposure to semivolatile organic compounds (SVOCs) that are emitted from consumer products and building materials in indoor environments is critical for reducing the associated health risks. Many modeling approaches have been developed for SVOC exposure assessment indoors, including the DustEx webtool. However, the applicability of these tools depends on the availability of model parameters such as the gas-phase concentration at equilibrium with the source material surface, y₀, and the surface-air partition coefficient, K_s, both of which are typically determined in chamber experiments. In this study, we compared two types of chamber design, a macro chamber, which downscaled the dimensions of a room to a smaller size with roughly the same surface-to-volume ratio, and a micro chamber, which minimized the sink-to-source surface area ratio to shorten the time required to reach steady state. The results show that the two chambers with different sink-to-source surface area ratios yield comparable steady-state gas- and surface-phase concentrations for a range of plasticizers, while the micro chamber required significantly shorter times to reach steady state. Using y₀ and K_s measured with the micro chamber, we conducted indoor exposure assessments for di-n-butyl phthalate (DnBP), di(2-ethylhexyl) phthalate (DEHP) and di(2-ethylhexyl) terephthalate (DEHT) with the updated DustEx webtool. The predicted concentration profiles correspond well with existing measurements and demonstrate the direct applicability of chamber data in exposure assessments.

Emissions of Formamide and Ammonia from Foam Mats: Online Measurement Based on Dopant-Assisted Photoionization TOFMS and Assessment of Their Exposure for Children

Formamide has been classified as a Class 1B reproductive toxicant to children by the European Union (EU) Chemicals Agency. Foam mats are a potential source of formamide and ammonia. Online dopant-assisted atmospheric pressure photoionization time-of-flight mass spectrometry (DA-APPI-TOFMS) coupled with a Teflon environmental chamber was developed to assess the exposure risk of formamide and ammonia from foam mats to children. High levels of formamide (average 3363.72 mg/m³) and ammonia (average 1586.78 mg/m³) emissions were measured from 21 foam mats with three different raw material types: ethylene-vinyl acetate (EVA: n = 7), polyethylene (PE: n = 7), and cross-linked polyethylene (XPE: n = 7). The 28 day emission testing for the selected PE mat showed that the emissions of formamide were 2 orders of magnitude higher than the EU emission limit of 20 μg/m³, and formamide may be a permanent indoor contaminant for foam mat products during their life cycle. The exposure assessment of children aged 0.5-6 years showed that the exposure dose was approximately hundreds of mg/kg-day, and the age group of 0.5-2 years was subject to much higher dermal exposures than others. Thus, this study provided key relevant information for further studies on assessing children's exposure to indoor air pollution from foam mats.

Health Risks Posed by Dermal and Inhalation Exposure to High Concentrations of Chlorinated Paraffins Found in Soft Poly(vinyl chloride) Curtains

Chlorinated paraffins (CPs) are used in many products, including soft poly(vinyl chloride) curtains, which are used in many indoor environments. Health hazards posed by CPs in curtains are poorly understood. Here, chamber tests and an indoor fugacity model were used to predict CP emissions from soft poly(vinyl chloride) curtains, and dermal uptake through direct contact was assessed using surface wipes. Short-chain and medium-chain CPs accounted for 30% by weight of the curtains. Evaporation drives CP migration, like for other semivolatile organic plasticizers, at room temperature. The CP emission rate to air was 7.09 ng/(cm² h), and the estimated short-chain and medium-chain CP concentrations were 583 and 95.3 ng/m³ in indoor air 21.2 and 172 μg/g in dust, respectively. Curtains could be important indoor sources of CPs to dust and air. The calculated total daily CP intakes from air and dust were 165 ng/(kg day) for an adult and 514 ng/(kg day) for a toddler, and an assessment of dermal intake through direct contact indicated that touching just once could increase intake by 274 μg. The results indicated that curtains, which are common in houses, could pose considerable health risks through inhalation of and dermal contact with CPs.

Endocrine modulating chemicals in food packaging: A review of phthalates and bisphenols

Phthalates and bisphenol chemicals have been widely used globally in packaging materials and consumer products for several decades. These highly functional chemicals have become a concern due to their toxicity (i.e., endocrine/hormone modulators) and ability to migrate from food contact materials (FCMs) into food matrices and the environment resulting in human and environmental health risks. FCMs, composed of postconsumer materials, are particularly high risk for containing these compounds. The evaluation of postconsumer recycled feedstocks in FCMs is compulsory and selection of an appropriate detection method to comply with applicable regulations is necessary to evaluate human and environmental safety. Numerous regulations have been proposed and passed globally for both compound classes that are recognized as priority pollutants by the United States Environmental Protection Agency and the European Union. Several brand owners and retailers have also released their own "restricted substance lists" due to the mounting consumer and regulatory concerns. This review article has two goals: (1) discuss the utilization, toxicology, human exposure routes, and occurrence levels of phthalates and bisphenols in FCMs and associated legislation in various countries and (2) discuss critical understanding and updates for detection/quantification techniques. Current techniques discussed include extraction and sample preparation methods (solid-phase microextraction [SPME], headspace SPME, Soxhlet procedure, ultrasound-assisted extraction), chromatographic techniques (gas, liquid, detectors), and environmental/blank considerations for quantification. This review complements a previous review of phthalates in foods from 2009 by discussing phthalate and bisphenol characteristics, analytical methods of determining concentrations in packaging materials, and their influence on the migration potential into food.

Simplified Unified BARGE Method to Assess Migration of Phthalate Esters in Ingested PVC Consumer Products

The unified bioaccessibility research group of Europe (BARGE) method (UBM) suggests using in vitro experimental conditions for simulating the release of chemicals from confined matrices, such as soils and sediments, in the human gastrointestinal tract. It contains comprehensive steps that simulate human digestion pathways and has good potential for application in the leaching of plastic additives from accidentally ingested plastic particles. However, its complexity could be a challenge for routine screening assessments of the migration of chemicals from consumer plastic products. In this study, the UBM was modified to assess the migration of plastic additives from consumer products with five model phthalate esters (i.e., dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), bis(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DNOP)) from polyvinyl chloride (PVC). The migration of phthalate esters was observed in four digestive phases (saliva, gastric, duodenal, and bile). Three separate experiments were conducted with the addition of (1) inorganic constituents only, (2) inorganic and organic constituents, and (3) inorganic and organic constituents in combination with digestive enzymes. While using enzymes with the UBM solution, the migrated mass for leached compounds was comparatively low (0.226 ± 0.04 μg) in most digestion phases, likely due to a self-generated coating of enzymes on the plastic materials. However, higher mass migration (0.301 ± 0.05) was observed when phthalate esters were analyzed in the UBM solution, excluding the enzymes. A ring test among six independent laboratories confirmed the robustness of the modified method. Therefore, we propose a simplified version of the original UBM designed mainly for the migration of inorganic elements using only the inorganic and organic components of the solution throughout all phases of digestion.

Effects of time, temperature, and sebum layer on migration rate of plasticizers in polyvinyl chloride products

Large amounts of plasticizers, such as di(2-ethylhexyl) phthalate (DEHP) and dioctyl terephthalate (DOTP), are added to various polyvinyl chloride (PVC) products. To assess the human exposure to these plasticizers on using PVC products, it is important to know their migration rate. However, conventional migration tests conducted at a fixed time and temperature are often insufficient for determining possible variations in migration rates with respect to time, temperature, and sebum layer. In this study, the migration rates of DEHP and DOTP from five PVC products were measured using a polydimethylsiloxane (PDMS) sampler at different times and temperatures, in the presence and absence of artificial sebum. Although the migrated mass of the plasticizers increased over time, the average migration rate decreased. The average migration rates increased with increasing temperature and in the presence of an artificial sebum layer between the product and the PDMS sampler. When the artificial sebum layer was added, the average migration rate increased considerably by a factor of 1.5-14, suggesting that sebum should be considered to avoid the underestimation of dermal exposure to highly hydrophobic plasticizers, such as DEHP and DOTP. Based on the measured values, a conceptual analysis was conducted to quantitatively assess the difference in the migration rate of plasticizers caused by the difference between the time set for the migration test and the exposure time when the product is used. To reduce uncertainties and the potential underestimation of dermal exposure, an appropriate time for the experiment should be set to simulate the exposure scenario of a given product.

Occurrence and health implications of heavy metals in preschool children's clothing manufactured in four Asian regions

Clothing may be a potential contributor to body metal burden in children. However, available information on heavy metals in children's clothing is extremely limited and the associated health risks remain poorly understood. This study investigated the concentrations of Pb, Cd, Co, Zn, Cr, As, Cu and Ni in new preschool children's clothing manufactured in four Asian regions. The children's clothing had higher levels of Ni and Cr but lower levels of Pb and Cd in comparison to the concentrations reported in other textile products. The concentrations of Cd were higher in the black clothing than those in the white and color samples. The non-cotton samples contained higher Co concentrations. The Pb concentrations in the samples manufactured in China were significantly higher than those in the other three regions. We estimated the dermal exposure doses for these metals and calculated the associated risks. The results indicated that the health risks from exposure to these metals in the children's clothing were acceptable. However, more research is required to investigate heavy metals and the associated risks in child clothing due to the increasing complexity of their materials and manufacturing processes.

Transfer of Frictional Contact Derived Phthalates from Pad Surface Enhances Dermal Exposure

Dermal exposure to chemicals derived from object surface contact is an important contributor to increased health risk. However, chemical transfer induced by mechanical friction between dermal and object surface has yet to be adequately addressed. To fill this knowledge gap, rubbing fabrics were used as surrogate skins to stimulate dermal mechanical friction with pad products with phthalates as target analytes. The results showed that the amounts of phthalates transferred increased linearly with contact burden (50-1000 g), contact duration (1-10 min), and sliding speed (3.0-9.0 cm s^-1). The surface texture of surrogate skins dictated the accumulation of phthalates. Net/pocket micro-surface structures of rubbing fabrics induced a higher accumulation of phthalates than U-shape structures of fabrics with a similar surface roughness. Covering of the pad surface by a layer of textile was effective in minimizing the transfer of phthalates induced by mechanical motion. The estimated transfer efficiency of bis(2-ethylhexyl) ester (DEHP) derived from rubbing friction (0.005-0.05%) upon the pad surface over 8 h was greater than those for gas-phase emission (0.00002-0.0005% over 24 h) and sweat transfer (0.008-0.012% over 24 h). These results indicated that dermal frictional contact with the surface of pad products was an important exposure pathway.

Study on the Physical, Thermal and Mechanical Properties of SEBS/PP (Styrene-Ethylene-Butylene-Styrene/Polypropylene) Blend as a Medical Fluid Bag

The presence of DEHP in PVC-based medical bags poses a significant health risk to patients undergoing blood transfusion. In order to fabricate safer medical fluid bag materials, the use of SEBS/PP polymer blend as a potential material was investigated. Polymeric blends with varying weight percentages of styrene-ethylene-butylene-styrene/polypropylene (SEBS/PP) were fabricated by melt mixing using an internal Haake mixer. The physical properties of the SEBS/PP polymer blends were investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD), and inductively coupled plasma–mass spectrometry (ICP-MS). In addition, measurements of the mechanical strength (tensile strength and Young’s modulus) as per ASTM 638, polymer hardness was tested using a durometer and swelling was analysed through water absorption and compared with commercial PVC-based blood bags. The results indicate that the SEBS/PP 50/50 blend has approximately similar characteristics as PVC-based blood bags. The SEBS/PP polymer blend possesses approximate tensile strength and Young’s modulus with values of 23.28 MPa and 14.42 MPa, respectively, to that of the conventional PVC blood bags. The results show that the SEBS/PP polymer blends have negligible zinc and aluminium migration with values of 1.6 and 2.1 mg/kg, respectively, and do not elute any harmful leachates, while the thermal studies indicate that the studied SEBS/PP materials are capable of withstanding steam sterilisation at 120 °C and cold storage below −40 °C. The investigated material can be utilized for medical fluid bags and contributes towards sustainable development goals, such as SDG 3 to ensure healthy lives and promote well-being, as well as SDG 12 to ensure sustainable consumption and production patterns.

Effects of DEHP, DEHT and DINP Alone or in a Mixture on Cell Viability and Mitochondrial Metabolism of Endothelial Cells In Vitro

Plasticizers are chemicals in high demand, used in a wide range of commercial products. Human are exposed through multiple pathways, from numerous sources, to multiple plasticizers. This is a matter of concern, as it may contribute to adverse health effects. The vascular system carries plasticizers throughout the body and therefore can interact with the endothelium. The aim of the study was to evaluate the in vitro toxicity on endothelial cells by considering the individual and the mixture effects of bis-(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP) or bis-(2-ethylhexyl) terephthalate (DEHT). In this study, their cytotoxicity on HMEC-1 cells was evaluated on cell function (viability, cell counting, total glutathione and intracellular adenosines) and mitochondrial function (mitochondrial respiration). Results showed cellular physiological perturbations induced with all the condition tested, excepted for DEHT. Plasticizers induced a cytotoxicity by targeting mitochondrial respiration, depleting mitochondrial ATP production and increasing glycolytic metabolism. Additionally, delayed effects were observed between the cellular and the mitochondrial parameters. These results suggest that endothelial cells could go through a metabolic adaptation to face plasticizer-induced cellular stress, to effectively maintain their cellular processes. This study provides additional information on the adverse effects of plasticizers on endothelial cells.

Occurrence of newly identified plasticizers in handwipes; development and validation of a novel analytical method and assessment of human exposure via dermal absorption

A novel analytical method for the monitoring of four newly identified plasticizers, namely di-propylene glycol dibenzoate (DiPGDB), tri-n-butyl trimellitate (TBTM), isooctyl 2-phenoxyethyl terephthalate (IOPhET) and bis 3,5,5-trimethylhexyl phosphate (TMHPh), in handwipes based on pulverization was developed and in-house validated. In total, 164 handwipe samples (paired with house dust and human urine) were collected during winter (n = 82) and summer (n = 82) 2019 from adults and toddlers living in Flanders, Belgium. Method LOQs ranged from 1 to 200 ng/g. The ranges of Σ_plasticizers were 70-5400 ng/g for winter and 70-3720 ng/g for summer. The detection frequencies were 39% for DiPGDB, 27% for TBTM and <5% for IOPhET and TMHPh in winter samples and 33% for DiPGDB, 21% for TBTM and <10% for IOPhET and TMHPh in summer ones. The dominant compound in handwipes was DiPGDB, with mean contributions of 74% and 83% for winter and summer, followed by TBTM (24% and 9.2%), TMHPh (1.8% and 8.1%) and IOPhET (<1% and <1%). Σ_plasticizers concentrations were positively correlated in summer with the use of sanitizer (r = 0.375, p < 0.05) and negatively correlated in winter with the use of personal care products (r = -0.349, p < 0.05). DiPGDB was found positively correlated with the age of the participants (r = 0.363, p < 0.05) and the time spent indoors (r = 0.359, p < 0.05), indicating indoor environment as a potential source. Levels of TBTM in handwipes were positively correlated with dust samples collected from the same households (r = 0.597, p < 0.05), and those detected in toddler handwipes were significantly higher compared to adults (p < 0.05). Human daily exposure via dermal absorption was evaluated using the dermal derived no effects level values (DNEL), available in the database of the European Chemicals Agency (ECHA) and estimated using the theoretical bio-accessible fractions per compound. Toddler exposure to TBTM was significantly higher compared to adults (T-test, p < 0.05). No risk for adverse human health effects was derived from the comparison with DNELs for all compounds.

Hazardous chemicals in outdoor and indoor surfaces: artificial turf and laminate flooring

BACKGROUND

Synthetic materials, increasingly used for indoor and outdoor surfaces including homes and playgrounds, may contain toxic chemicals. Infants have a higher potential of exposure to chemicals in these materials, which may pose a risk to their health.

OBJECTIVE

To understand potential risks related to outdoor surface coverings, based on a review of the literature and regulations, and to assess levels of hazardous chemicals in surface coverings in Israel.

METHODS

We reviewed the literature and regulations on artificial turf. We tested 46 samples of surfaces for trace metals in synthetic playground surfaces; trace metals, phthalates, and di(2-ethylhexyl) terephthalate (DEHT) in synthetic grass, and phthalates, DEHT and formaldehyde in laminate flooring.

RESULTS

Twelve studies reporting high levels of polycyclic aromatic hydrocarbons (PAH), and varying levels of trace metals in synthetic playground surfaces were identified, as well as five international regulations on lead with maximum acceptable concentrations in the range 40-500 mg/kg. Surface tests showed that 20 out of 30 samples of synthetic playground surfaces exceeded relevant standards for trace metals, of which five had cadmium levels ≥30 mg/kg and four had chromium levels ≥510 mg/kg. In synthetic grass, three out of eight samples exceeded relevant standards, with lead levels ≥1200 mg/kg. In Laminate flooring (n = 8) formaldehyde levels were in the range of 0.7-1.2 mg/m² formaldehyde, and five samples contained ~5% DEHT.

SIGNIFICANCE

The literature on chemicals in surfaces is limited, but indicates some exceedance of regulatory limits. Trace metals in synthetic playground surfaces and synthetic grass, not regulated in Israel, exceeded relevant international standards in 72% of samples. Laminate flooring, regulated for formaldehyde, did not exceed the 3.5 mg/m² standard, but contained DEHT, a replacement for ortho-substituted phthalates. The results of this preliminary study show that flooring surfaces may be a source of children's exposure to toxic chemicals.

IMPACT STATEMENT

Synthetic surfaces are increasingly being used in, for example, children's playgrounds and sports fields. Exceedances of regulatory limits from other jurisdictions, of heavy metal levels in most outdoor surfaces sampled in Israel indicates the potential for children's exposure. Domestic regulations should be implemented to reduce the risk to children from exposure to these surfaces.

Phthalates in house dust in Chinese urban residences: Concentrations, partition, origin and determinants

Exposure to phthalates poses adverse health impacts to human beings. In this study, we analyzed 7 phthalates in dust samples, which were collected with vacuum cleaner from 40 to 31 residences in Beijing in summer and winter, respectively. The major phthalates (median concentration in the summer and winter, respectively) were DiBP (55 and 40 ng/mg), DnBP (99 and 30 ng/mg) and DEHP (795 and 335 ng/mg). The concentrations were significantly influenced by season and residence time of house dust. The concentrations of phthalates in dust on plastic surfaces were highest, followed by those on wooden and fabric surfaces. The dust-air partition coefficients (K_d) were calculated: the median values were 0.13, 0.02 and 5.62 m³/mg in the summer and 0.06, 0.018 and 0.76 m³/mg in the winter for DiBP, DnBP and DEHP, respectively. A comparison with K_d* at equilibrium state suggested that partition between air and dust deviated from equilibrium state in both seasons. The results also revealed that dust-phthalates in the summer may completely originate from source materials via direct transfer and external physical process; while dust-phthalates in the winter may come from both air (via partition) and source material (via direct transfer and external physical process). The influence of temperature on dust-phthalate concentrations differed by season, owing to different origin of dust-phthalates in two seasons. Polar organic components in dust, which are products of reactions between O₃ and unsaturated hydrocarbons in dust, likely played an important role in fate and transport of phthalates. The presence of them resulted in the significant associations between dust-phthalate concentrations and air humidity in the summer. Moreover, the impacts of indoor PM_2.5 concentrations, traffic conditions surrounding residence, household lifestyle and number of occupants were also observed. The mechanisms behind those observations were discussed.

Molecular insights into substrate recognition and catalysis by phthalate dioxygenase from Comamonas testosteroni

Phthalate, a plasticizer, endocrine disruptor, and potential carcinogen, is degraded by a variety of bacteria. This degradation is initiated by phthalate dioxygenase (PDO), a Rieske oxygenase (RO) that catalyzes the dihydroxylation of phthalate to a dihydrodiol. PDO has long served as a model for understanding ROs despite a lack of structural data. Here we purified PDO_KF1 from Comamonas testosteroni KF1 and found that it had an apparent k_cat/K_m for phthalate of 0.58 ± 0.09 μM^-1s^-1, over 25-fold greater than for terephthalate. The crystal structure of the enzyme at 2.1 Å resolution revealed that it is a hexamer comprising two stacked α₃ trimers, a configuration not previously observed in RO crystal structures. We show that within each trimer, the protomers adopt a head-to-tail configuration typical of ROs. The stacking of the trimers is stabilized by two extended helices, which make the catalytic domain of PDO_KF1 larger than that of other characterized ROs. Complexes of PDO_KF1 with phthalate and terephthalate revealed that Arg207 and Arg244, two residues on one face of the active site, position these substrates for regiospecific hydroxylation. Consistent with their roles as determinants of substrate specificity, substitution of either residue with alanine yielded variants that did not detectably turnover phthalate. Together, these results provide critical insights into a pollutant-degrading enzyme that has served as a paradigm for ROs and facilitate the engineering of this enzyme for bioremediation and biocatalytic applications.

Phthalate Plasticizers in Children's Products and Estimation of Exposure: Importance of Migration Rate

Plasticizers are added to diverse consumer products including children's products. Owing to their potential for endocrine disruption, the use of phthalate plasticizers is restricted in many children's products. In this study, exposure to five phthalate esters (dibutylphthalate, di(2-ethylhexyl) phthalate (DEHP), diethyl phthalate, di-isobutyl phthalate, and diisononyl phthalate (DINP)) and an alternative (di-ethylhexyl adipate) was assessed by the use of children's products based on chemical analysis of 3345 products purchased during 2017 and 2019 in Korea. Plasticizers were found above the detection limits in 387 products, and DEHP and DINP were the two most predominantly detected plasticizers. Deterministic and probabilistic estimation of the margin of exposure at a screening level revealed that the use of children's products might be an important risk factor. However, it is also highly likely that the exposure could be overestimated, because the migration rate was estimated based solely on the content of plasticizers in children's products. Chemical migration is a key process determining the absorption of plasticizers from products; thus, further refinements in experimental determination or model estimation of the migration rate are required.

Percutaneous Penetration and Metabolism of Plasticizers by Skin Cells and Its Implication in Dermal Exposure to Plasticizers by Skin Wipes

Numerous studies focused on the human exposure to plasticizers via dermal contact; however, the percutaneous penetration of plasticizers was seldom considered in exposure assessment. In the present study, skin wipes of palms, back-of-hands, and forehead were collected from 114 participants (ages: 18-27). There was no significant difference between the levels of phthalates from palms and back-of-hand, while all phthalates collected from the forehead were significantly higher than those from palms and back-of-hand (p < 0.001); di(2-ethylhexyl)phthalate levels were substantially higher than other detected phthalates followed by di(n-butyl)phthalate and di(isobutyl)phthalate (DiBP), and for alternative plasticizers, bis-2-ethylhexyl terephthalate levels were substantially higher than acetyltributyl citrate and bis-2-ethylhexyladipate. Skin permeation and metabolism of phthalates was assessed using human skin equivalent models. The permeability coefficient (k_p) values of phthalates were significantly negatively correlated with their log octanol-water partition coefficient (log K_ow), while a significantly positive correlation was found between the log K_ow and the cumulative amounts of phthalates in the cells. The proportion of phthalate intake via dermal exposure to skin wipes ranges from 1.3% (for dimethyl phthalate) to 8.6% (for DiBP) and suggests that dermal absorption is a significant route for adult phthalate exposure.

Skin transferability of phthalic acid ester plasticizers and other plasticizers using model polyvinyl chloride sheets

The transferability of phthalic acid esters (PAEs) and other plasticizers, from model polyvinyl chloride (PVC) sheets to the skin of 11 subjects was assessed by measuring the amount of substance transferred using PVC sheets containing PAEs and alternative plasticizers of different types and contents. For all subjects, the transferred amount, from sheets containing 28 wt% PAE or from mixed sheets containing 14 wt% each of di (2-ethylhexyl) phthalate (DEHP) and other PAE, was greater than that from sheets containing 15 wt% each of PAE or alternative plasticizer only. A comparison of the transferability of five types of PAE showed that transfer tended to occur more readily as the n-octanol-water partition coefficient increased, suggesting that PAE hydrophobicity affected its transferability. The transferability of the alternative plasticizers di(2-ethylhexyl) terephthalate and 1,2-cyclohexane dicarboxylic acid diisononyl ester showed a similar trend; however, the transferred amount tended to be higher from model PVC sheets containing 28 wt% PAE or mixed with DEHP. The transferability of PAEs and alternative plasticizers was higher for certain subjects, suggesting individual differences in the transferability of chemicals to the subject's skin surface and is the presence of a group of people comparatively more susceptible to such transfer.

Phthalates in preschool children's clothing manufactured in seven Asian countries: Occurrence, profiles and potential health risks

Phthalates could be introduced into clothing as chemical additives or impurities, becoming a potential source of human exposure. We measured the concentrations of 15 phthalates in new preschool children's clothing manufactured in seven Asian countries. Phthalates were prevalent in all samples, and total concentrations were 2.92-223 μg/g, indicating a moderate contamination level. Bis(2-ethylhexyl) phthalate, di(isobutyl) phthalate and di-n-butyl phthalate were the most abundant phthalates measured, representing a median of 48.5 %, 13.6 % and 13.4 % of the total concentrations, respectively. Total concentrations did not differ significantly by country of manufacture, while the concentrations of individual phthalates and their composition profiles varied widely. We also found differing phthalate levels by item type, fabric composition, and color. Under the assumed two exposure scenarios, the median of summed dermal exposure doses of six phthalate were 539 and 950 ng/kg of body weight per day, respectively. When children wore trousers, long-sleeved shirts, briefs and socks at the same time, the reproductive risks exceeded acceptable level, although the carcinogenic risk of DEHP was low. Our results suggested that new clothing is an important route of phthalate exposure to preschool children. More research is required to investigate the contaminations and associated with risks in child clothing.

Identification of plastic toys contaminated with volatile organic compounds using QCM gas sensor array

In this paper, we propose a fast and easy-to-use analytical method to identify the children toys contaminated with potentially dangerous substances from the class of volatile organic compounds (VOCs). It is shown that the use of cross-sensitive gas sensor array based on piezoelectric sensors, modified with different sorbents, allows reliable recognition of items with the elevated levels of VOCs. Applying chemometric methods for processing of the sensor array data, it is possible to classify the toys into clean and hazardous ones with sensitivity and accuracy around 96%. Taking into account the simplicity of the suggested procedure, it appears to be an attractive option for cost-effective pre-screening of potentially dangerous plastic toys in comparison with the expensive and time-consuming chromatographic methods.

Qualitative approach to comparative exposure in alternatives assessment

Most alternatives assessments (AAs) published to date are largely hazard-based rankings, thereby ignoring potential differences in human and/or ecosystem exposures; as such, they may not represent a fully informed consideration of the advantages and disadvantages of possible alternatives. Building on the 2014 US National Academy of Sciences recommendations to improve AA decisions by including comparative exposure assessment into AAs, the Health and Environmental Sciences Institute's (HESI) Sustainable Chemical Alternatives Technical Committee, which comprises scientists from academia, industry, government, and nonprofit organizations, developed a qualitative comparative exposure approach. Conducting such a comparison can screen for alternatives that are expected to have a higher or different routes of human or environmental exposure potential, which together with consideration of the hazard assessment, could trigger a higher tiered, more quantitative exposure assessment on the alternatives being considered, minimizing the likelihood of regrettable substitution. This article outlines an approach for including chemical ingredient- and product-related exposure information in a qualitative comparison, including ingredient and product-related parameters. A classification approach was developed for ingredient and product parameters to support comparisons between alternatives as well as a methodology to address exposure parameter relevance and data quality. The ingredient parameters include a range of physicochemical properties that can impact routes and magnitude of exposure, whereas the product parameters include aspects such as product-specific exposure pathways, use information, accessibility, and disposal. Two case studies are used to demonstrate the application of the methodology. Key learnings and future research needs are summarized. Integr Environ Assess Manag 2018;00:000-000. © 2018 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Emissions of DEHP-free PVC flooring

Degrading 2-ethylhexyl-containing PVC floorings (eg DEHP-PVC floorings) and adhesives emit 2-ethylhexanol (2-EH) in the indoor air. The danger of flooring degradation comes from exposing occupants to harmful phthalates plasticisers (eg DEHP), but not from 2-EH as such. Since the EU banned the use of phthalates in sensitive applications, the market is shifting to use DEHP-free and alternative types of plasticisers in PVC products. However, data on emissions from DEHP-free PVC floorings are scarce. This study aimed at assessing the surface and bulk emissions of two DEHP-free PVC floorings over three years. The floorings were glued on the screed layer of concrete casts at 75%, 85%, and 95% RH. The volatile organic compounds (VOCs) were actively sampled using FLEC (surface emissions) and micro-chamber/thermal extractor (µ-CTE, bulk emissions) onto Tenax TA adsorbents and analyzed with TD-GC-MS. 2-EH, C9-alcohols, and total volatile organic compound (TVOC) emissions are reported. Emissions at 75% and 85% RH were similar. As expected, the highest emissions occurred at 95% RH. 2-EH emissions originated from the adhesive. Because the two DEHP-free floorings tested emitted C9-alcohols at all tested RH, it makes the detection of flooring degradation harder, particularly if the adhesive used does not emit 2-EH.

Comparative analysis of endocrine disrupting effects of major phthalates in employed two cell lines (MVLN and H295R) and embryonic zebrafish assay

Endocrine disruption potentials of phthalates have been widely recognized, but relatively little is known about relative potency of major phthalates. In the present study, six phthalates were chosen, i.e., dimethyl phthalate (DMP), diethyl phthalate (DEP), di(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DnOP), diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP), and their endocrine disruption effects were evaluated by employing two cell lines and an embryonic zebrafish assay. Binding affinity with estrogen receptors (ERs) and effects on steroidogenesis were evaluated with MVLN and H295R cell assays, respectively. In zebrafish embryos, transcription of genes regulating steroid hormone balance and estrogen receptors was measured. Exposure to DMP, DEP, DEHP, and DnOP significantly increased E2/T ratio in H295R cells. However, no significant binding affinity to ERs was observed in MLVN cells. Exposure to DEHP influenced the expression of vtg1, esr1, and cyp19a1b genes in zebrafish larvae. DMP, DEP, DINP, and DIDP exposure led to significant transcriptional changes even at lower exposure concentrations, suggesting their greater endocrine disruption potency than DEHP in zebrafish. Our findings demonstrate that endocrine disruption upon phthalate exposure varies between in vitro and in vivo assay, and a battery of tests are warranted to understand endocrine disruption potentials of phthalates. Consequences of long-term exposure to phthalates other than DEHP warrant further evaluations.

Pregnancy phthalate metabolite concentrations and infant birth weight by gradations of maternal glucose tolerance

BACKGROUND

Higher birth weight is an important adverse outcome associated with hyperglycemia in pregnancy. Recent studies suggest that phthalate exposure is associated with elevated glucose levels in pregnant women, with implications for higher birth weight in the offspring. No study to date has investigated the association between prenatal phthalate exposure on infant high birth weight accounting for the range of pregnancy glucose levels.

METHODS

A total of 350 women participating in an ongoing pregnancy cohort had data available on urinary phthalate metabolite concentrations at up to four time points across pregnancy. Urinary phthalate metabolites were averaged across pregnancy and log-transformed, specific gravity-adjusted and analyzed in quartiles. Birth weight was examined continuously (in grams), as well as dichotomized as large for gestational age (>90^th percentile). Glucose levels were assessed based on Results from 50-g glucose challenge tests as a part of screening for gestational diabetes conducted at 24-28 weeks gestation, and grouped into 3 categories <120 mg/dL, 120-<140 mg/dL and ≥140 mg/dL. Multivariable linear regression was performed, adjusting for potential confounders in the overall population and stratified by pregnancy glucose levels.

RESULTS

Approximately 20% of infants born to women with glucose levels ≥140 mg/dL were large for gestational age. Average mono-ethyl phthalate (MEP) concentrations were higher among women who had glucose levels ≥140 mg/dL (geometric mean 140.9 μg/L; 95% CI: 91.6-216.8); however, higher MEP concentrations were not associated with higher birth weight. When stratified by maternal glucose levels, there was a suggestive association between higher concentrations of mono-(3-carboxypropyl) phthalate (MCPP) and higher birth weight among women with glucose levels ≥140 mg/dL (adj. birth weight: 569.2 g; 95% CI: 14.1, 1178.2).

CONCLUSIONS

Higher urinary phthalate metabolite concentrations were not significantly associated with higher birth weight. Counter to our hypothesis, women with higher glucose levels and higher urinary phthalate metabolites did not deliver babies with higher birth weight.

A general mechanistic model for predicting the fate and transport of phthalates in indoor environments

A mechanistic model that considers particle dynamics and their effects on surface emissions and sorptions was developed to predict the fate and transport of phthalates in indoor environments. A controlled case study was conducted in a test house to evaluate the model. The model-predicted evolving concentrations of benzyl butyl phthalate in indoor air and settled dust and on interior surfaces are in good agreement with measurements. Sensitivity analysis was performed to quantify the effects of parameter uncertainties on model predictions. The model was then applied to a typical residential environment to investigate the fate of di-2-ethylhexyl phthalate (DEHP) and the factors that affect its transport. The predicted steady-state DEHP concentrations were 0.14 μg/m³ in indoor air and ranged from 80 to 46 000 μg/g in settled dust on various surfaces, which are generally consistent with the measurements of previous studies in homes in different countries. An increase in the mass concentration of indoor particles may significantly enhance DEHP emission and its concentrations in air and on surfaces, whereas increasing ventilation has only a limited effect in reducing DEHP in indoor air. The influence of cleaning activities on reducing DEHP concentration in indoor air and on interior surfaces was quantified, and the results showed that DEHP exposure can be reduced by frequent and effective cleaning activities and the removal of existing sources, though it may take a relatively long period of time for the levels to drop significantly. Finally, the model was adjusted to identify the relative contributions of gaseous sorption and particulate-bound deposition to the overall uptake of semi-volatile organic compounds (SVOCs) by indoor surfaces as functions of time and the octanol-air partition coefficient (K_oa ) of the chemical. Overall, the model clarifies the mechanisms that govern the emission of phthalates and the subsequent interactions among air, suspended particles, settled dust, and interior surfaces. This model can be easily extended to incorporate additional indoor source materials/products, sorption surfaces, particle sources, and room spaces. It can also be modified to predict the fate and transport of other SVOCs, such as phthalate-alternative plasticizers, flame retardants, and biocides, and serves to improve our understanding of human exposure to SVOCs in indoor environments.

Equilibrium Relationship between SVOCs in PVC Products and the Air in Contact with the Product

Phthalates and phthalate alternatives are semivolatile organic compounds (SVOCs) present in many PVC products as plasticizers to enhance product performance. Knowledge of the mass-transfer parameters, including the equilibrium concentration in the air in contact with the product surface ( y₀), will greatly improve the ability to estimate the emission rate of SVOCs from these products and to assess human exposure. The objective of this study was to measure y₀ for different PVC products and to evaluate its relationship with the material-phase concentrations ( C₀). Also, C₀ and y₀ data from other sources were included, resulting in a substantially larger data set ( N_total = 34, T = 25 °C) than found in previous studies. The results show that the material/gas equilibrium relationship does not follow Raoult's law and that therefore the assumption of an ideal solution is invalid. Instead, Henry's law applies, and the Henry's law constant for all target SVOCs consists of the respective pure liquid vapor pressure and an activity coefficient γ, which accounts for the nonideal nature of the solution. For individual SVOCs, a simple partitioning relationship exists, but Henry's law is more generally applicable and will be of greater value in rapid exposure assessment procedures.

Concentrations of trace metals, phthalates, bisphenol A and flame-retardants in toys and other children's products in Israel

Trace metals and synthetic chemicals including phthalates, bisphenol A and flame retardants, are widely used in toys and childcare products, and may pose acute or chronic adverse health effects in children. In Israel, certain chemicals are regulated in childcare products, but there are still regulatory gaps. We tested regulated and unregulated contaminants in 174 item parts from 70 childcare items with potentially high oral or dermal exposure, including 22 children's jewelry items, 14 toys, 7 diaper-changing mats, 6 baby mattresses, 7 baby textiles and 14 feeding and bathing items. In children's jewelry, an unregulated product in Israel, 23% of samples exceeded the US standard for lead. In toys, a regulated product, we did not detect trace metals above the Israeli standard. In textiles, baby mattresses and diaper-changing mats, phthalates exceeded the European Union standard in 14-45% of tests with a mean of 6.74% by mass for diisononyl phthalate, and 1.32% by mass for di(2-ethylhexyl) phthalate. BPA migration exceeded the EU standard in 14-45% of tests with a mean of 1.03 ppm. The flame retardants polybrominated biphenyls, pentabromodiphenyl, octabromodiphenyl ether, tris(2,3-dibromopropyl) phosphate and tris-(aziridinyl)-phosphine oxide were not detected. For products regulated in Israel, our findings suggest general compliance with mandatory standards. However, a lack of comprehensive chemical regulation means that there are regulatory gaps, and products not regulated in Israel may contain high levels of chemical contamination, exceeding US or EU regulations. The results of this study have prompted the development of an Israeli safety standard for children's jewelry.

A quantitative property-property relationship for the internal diffusion coefficients of organic compounds in solid materials

Indoor releases of organic chemicals encapsulated in solid materials are major contributors to human exposures and are directly related to the internal diffusion coefficient in solid materials. Existing correlations to estimate the diffusion coefficient are only valid for a limited number of chemical-material combinations. This paper develops and evaluates a quantitative property-property relationship (QPPR) to predict diffusion coefficients for a wide range of organic chemicals and materials. We first compiled a training dataset of 1103 measured diffusion coefficients for 158 chemicals in 32 consolidated material types. Following a detailed analysis of the temperature influence, we developed a multiple linear regression model to predict diffusion coefficients as a function of chemical molecular weight (MW), temperature, and material type (adjusted R² of .93). The internal validations showed the model to be robust, stable and not a result of chance correlation. The external validation against two separate prediction datasets demonstrated the model has good predicting ability within its applicability domain (Rext2>.8), namely MW between 30 and 1178 g/mol and temperature between 4 and 180°C. By covering a much wider range of organic chemicals and materials, this QPPR facilitates high-throughput estimates of human exposures for chemicals encapsulated in solid materials.

Exposure to the plasticizer di(2-ethylhexyl) terephthalate (DEHTP) in Portuguese children - Urinary metabolite levels and estimated daily intakes

Classical ortho-phthalate plasticizers are, due to their endocrine disrupting potency and reproductive toxicity, increasingly replaced by alternative plasticizers. Di(2-ethylhexyl) terephthalate (DEHTP) is one of these substitutes. In this study, we investigated DEHTP exposure in 107 Portuguese children (4-17years old) by analyzing specific DEHTP metabolites in their urine using a newly developed LC-MS/MS method. We could detect the major, specific DEHTP metabolite mono(2-ethyl-5-carboxypentyl) terephthalate (5cx-MEPTP) in 100% of the samples with levels above the limit of quantification in 96% of the samples (median concentration 4.19μg/L; 95th percentile 26.4μg/L; maximum 3400μg/L). Other minor DEHTP metabolites (5OH-MEHTP, 5oxo-MEHTP and 2cx-MMHTP) were detected at lower rates and levels. Daily DEHTP intakes calculated from urinary 5cx-MEPTP levels were generally far below the tolerable daily intake (TDI) of 1000μg/kgbw/d (median 0.67μg/kgbw/d; 95th percentile 6.25μg/kgbw/d; maximum 690μg/kgbw/d). However, for one child the biomarker-derived health-based guidance value (HBM-I value) for 5cx-MEPTP of 1800μg/L was exceeded by about a factor of two. Levels of 5cx-MEPTP and calculated daily DEHTP intakes were higher in normal/under-weight children who nourished on their usual diet compared to overweight/obese children who received nutritional guidance with fresh and unprocessed food (p=0.043 and p<0.001 respectively). This indicates to processed and fatty foodstuff as a major source of DEHTP exposure. Additionally, we found children of lower age having higher DEHTP intakes (p=0.045). Again, foodstuff as a major DEHTP source, together with other child specific DEHTP sources such as mouthing of toys or ingestion of dust might be contributing factors. With the present study, we provide a first data set on the omnipresent DEHTP exposure in children. So far, general levels of DEHTP exposure seem no cause for concern. However, due to the increasing use of DEHTP as an ortho-phthalate substitute, possible increasing exposures in the future should be followed closely.

Exposure of Portuguese children to the novel non-phthalate plasticizer di-(iso-nonyl)-cyclohexane-1,2-dicarboxylate (DINCH)

Di-(iso-nonyl)-cyclohexane-1,2-dicarboxylate (DINCH) is used as substitute for high molecular weight phthalate plasticizers such as di-(2-ethylhexyl) phthalate (DEHP) and di-(iso-nonyl) phthalate (DINP). Due to a rapid substitution process we have to assume omnipresent and increasing DINCH exposures. The aim of this study was to evaluate DINCH exposure in 112 children (4-18years old) from Portugal, divided in two groups: 1) normal-/underweight following the usual diet; and 2) obese/overweight but under strict nutritional guidance. First morning urine samples were collected during the years 2014 and 2015. Oxidized DINCH metabolites (OH-MINCH, oxo-MINCH, cx-MINCH) were analyzed after enzymatic hydrolysis via on-line HPLC-MS/MS with isotope dilution quantification. We detected DINCH metabolites in all analyzed samples. Urinary median (95th percentile) concentrations were 2.14μg/L (15.91) for OH-MINCH, followed by 1.10μg/L (7.54) for oxo-MINCH and 1.08μg/L (7.33) for cx-MINCH. We observed no significant differences between the two child-groups; only after creatinine adjustment, we found higher metabolite concentrations in the younger compared to the older children. Median (95th percentile) daily DINCH intakes were in the range of 0.37 to 0.76 (2.52 to 5.61) μg/kg body weight/day depending on calculation model and subpopulation. Body weight related daily intakes were somewhat higher in Group 1 compared to Group 2, irrespective of the calculation model. However, in terms of absolute amounts (μg/day), DINCH intakes were higher in Group 2 compared to Group 1. In regard to age, we calculated higher intakes for the younger children compared to older children, but only with the creatinine-based model. This new data for southern European, Portuguese children adds information to the scarce knowledge on DINCH, confirming omnipresent exposure and suggesting higher exposures in children than adults. Significant sources and routes of exposure have yet to be unveiled. For now, all calculated daily intakes are far below established health benchmark levels (TDI, RfD). However, rapidly increasing exposures have to be expected over the next years.

Survey on plasticizers currently found in PVC toys on the Swiss market: Banned phthalates are only a minor concern

Plasticizers in toys are a recurring source of criticism and concern, as consumers feel they may endanger the health of their children. Most of the information available in literature concerns the presence or absence of certain phthalic acid ester plasticizers. Very little information can be found in the public domain with respect to the actually used plasticizers at a given time and place. In this paper, we present the plasticizer composition of 118 samples from 88 polyvinyl chloride toys found on the Swiss market in autumn 2015. Bis(2-ethylhexyl) terephthalate (DEHT) was by far the most frequent main plasticizer in the analyzed samples, which is a change when compared to the plasticizers found in toys and child care articles in 2007. Furthermore, the data show that the banned phthalates in toys are only a minor concern. The occurrence, however, is not evenly distributed between importers. If a toy is not designed to be sold on the European market by the manufacturer, it seems to be more likely to contain a banned phthalic acid ester.

Adsorption of Phthalates on Impervious Indoor Surfaces

Sorption of semivolatile organic compounds (SVOCs) onto interior surfaces, often referred to as the "sink effect", and their subsequent re-emission significantly affect the fate and transport of indoor SVOCs and the resulting human exposure. Unfortunately, experimental challenges and the large number of SVOC/surface combinations have impeded progress in understanding sorption of SVOCs on indoor surfaces. An experimental approach based on a diffusion model was thus developed to determine the surface/air partition coefficient K of di-2-ethylhexyl phthalate (DEHP) on typical impervious surfaces including aluminum, steel, glass, and acrylic. The results indicate that surface roughness plays an important role in the adsorption process. Although larger data sets are needed, the ability to predict K could be greatly improved by establishing the nature of the relationship between surface roughness and K for clean indoor surfaces. Furthermore, different surfaces exhibit nearly identical K values after being exposed to kitchen grime with values that are close to those reported for the octanol/air partition coefficient. This strongly supports the idea that interactions between gas-phase DEHP and soiled surfaces have been reduced to interactions with an organic film. Collectively, the results provide an improved understanding of equilibrium partitioning of SVOCs on impervious surfaces.

Human sex hormone-binding globulin as a potential target of alternate plasticizers: an in silico study

BACKGROUND

Currently, alternate plasticizers are used to replace phthalate plasticizers in children's toys, medical equipments and food packaging, due to the adverse effects of phthalate compounds on human health and laws prohibiting their use. Current information regarding the safety and potential adverse effects of alternate plasticizers is limited and recent studies have found alternate plasticizers to display similar characteristics to those observed in phthalate plasticizers. This study was undertaken to evaluate and predict the potential endocrine disrupting activity of the three most commonly used alternate plasticizers: di(2-ethylhexyl)terephthalate (DEHT), tris(2-ethylhexyl)trimellitate (TOTM), and diisononyl hexahydrophthalate (DINCH) against human sex hormone-binding globulin (SHBG) using in silico approaches.

MATERIALS AND METHODS

The crystal structure of human SHBG (Id: 1D2S) was retrieved from Protein Data Bank. PubChem database was searched for the structures of alternate plasticizers, DEHT, TOTM, and DINCH. Docking was performed using Glide (Schrodinger) Induced Fit Docking module.

RESULTS

Induced Fit Docking of three alternate plasticizer compounds indicated that each of the three compounds fitted well into the steroid binding pocket of SHBG. Docking displays showed interactions of alternate plasticizers with 25-30 amino-acid residues of SHBG; 18-20 amino residues overlapped between the natural ligand, DHT, and the three compounds (commonality of 82-91 %). The hydrogen-bonding interaction of the amino-acid residue, Asn-82, of SHBG was also present in displays of DHT and all the three alternate phthalates. The binding affinity of all the three alternate phthalates was higher than DHT; maximum in DINCH followed by TOTM and DEHT.

CONCLUSION

Our results suggested that the three alternate plasticizers have potential to engage the important interacting residues of SHBG and thus interfere in its steroid homeostatic function.

Simple Method To Measure the Vapor Pressure of Phthalates and Their Alternatives

Phthalates and alternative plasticizers are semivolatile organic compounds (SVOCs), an important class of indoor pollutants that may have significant adverse effects on human health. Unfortunately, models that predict emissions of and the resulting exposure to SVOCs have substantial uncertainties. One reason is that the characteristics governing emissions, transport, and exposure are usually strongly dependent on vapor pressure. Furthermore, available data for phthalates exhibit significant variability, and vapor pressures for the various alternatives are usually unavailable. For these reasons, a new approach based on modeling of the evaporation process was developed to determine vapor pressures of phthalates and alternate plasticizers. A laminar flow forced convection model was used in the design of a partial saturator (PS) tube. The mass transfer mechanisms in the PS tube are accurately modeled and enable the determination of vapor pressure even when the carrier gas is not completely saturated, avoiding the complicated procedure to establish vapor saturation. The measured vapor pressures ranged from about 10(-2) to 10(-7) Pa. Compared to the traditional gas saturation method, the model-based approach is advantageous in terms of both predictability and simplicity. The knowledge provides new insight into experimental design and a sound basis for further method development.

Cosmetics use and age at menopause: is there a connection?

Cosmetics contain a vast number of chemicals, most of which are not under the regulatory purview of the Food and Drug Administration. Only a few of these chemicals have been evaluated for potential deleterious health impact: parabens, phthalates, polycyclic aromatic hydrocarbons, and siloxanes. A review of the ingredients in the best-selling and top-rated products of the top beauty brands in the world, as well as a review of highlighted chemicals by nonprofit environmental organizations, reveals 11 chemicals and chemical families of concern: butylated hydroxyanisole/butylated hydroxytoluene, coal tar dyes, diethanolamine, formaldehyde-releasing preservatives, parabens, phthalates, 1,4-dioxane, polycyclic aromatic hydrocarbons, siloxanes, talc/asbestos, and triclosan. Age at menopause can be affected by a variety of mechanisms, including endocrine disruption, failure of DNA repair, oxidative stress, shortened telomere length, and ovarian toxicity. There is a lack of available studies to make a conclusion regarding cosmetics use and age at menopause. What little data there are suggest that future studies are warranted. Women with chronic and consistent use of cosmetics across their lifespan may be a population of concern. More research is required to better elucidate the relationship and time windows of vulnerability and the effects of mixtures and combinations of products on ovarian health.