Association between indoor exposure to semi-volatile organic compounds and building-related symptoms among the occupants of residential dwellings

Seasonal variation and influence factors of organophosphate esters in air particulate matter of a northeastern Chinese test home

To investigate the seasonal variation of organophosphate esters (OPEs) in air particulate matter (PM) and the corresponding influence factors in indoor environment, 104 indoor PM samples were collected in a test home, Harbin, China, from March 2017 to March 2018. The Σ₁₂OPEs concentrations ranged from 0.41 ng/m³ to 940 ng/m³. Tris(1-chloro-2-propyl) phosphate (TCIPP) was the most abundant OPE and accounted for 83.2% of the total OPEs. The Σ₁₂OPEs concentrations in spring and summer were higher than those in autumn and winter. Outdoor total suspended particles (TSP) were the main factor that affected the concentration variation of OPEs in PM samples in the test home. Comparisons of the gas/particle (G/P) partitioning equilibrium models indicated that the Dachs-Eisenreich (D-E) model estimates were more reliable than the other models in this study. The particle fractions of OPEs with log K_OA > 10.51 that predicted by all four models generally well matched the measured OPE particle fractions in the literatures. To OPEs with lower molecular weight, inhalation was the main exposure route and ingestion contributed mostly to OPEs with higher molecular weight. In addition, the estimated daily intakes (EDIs) and carcinogenic risks (CRs) posed by OPEs were all below the recommended values, indicating that the current OPE levels in the test home were within the safe thresholds.

Organophosphorus Flame Retardants: A Global Review of Indoor Contamination and Human Exposure in Europe and Epidemiological Evidence

We aimed to identify high-priority organophosphorus flame retardants for action and research. We thus critically reviewed literature between 2000 and 2019 investigating organophosphorus flame retardants' presence indoors and human exposure in Europe, as well as epidemiological evidence of human effects. The most concentrated compounds indoors were tris(2-butoxyethyl)phosphate (TBOEP), tris(1-chloro-2-propyl)phosphate (TCIPP), tris(2,3-dichloropropyl)phosphate (TDCIPP). TBOEP and TCIPP were the most consistently detected compounds in humans' urine, hair or breast milk as well as tris (butyl) phosphate (TNBP) and tris (phenyl) phosphate (TPHP). Notably, epidemiological evidence concerned reprotoxicity, neurotoxicity, respiratory effects and eczema risk for TDCIPP, eczema increase for TBOEP, and neurodevelopmental outcomes for Isopropylated triarylphosphate isomers (ITPs). Given the ubiquitous presence indoors and the prevalence of exposure, the growing health concern seems justified. TDCIPP and TPHP seem to be of particular concern due to a high prevalence of exposure and epidemiological evidence. TBOEP and TNBP require epidemiological studies regarding outcomes other than respiratory or dermal ones.

A broad range of organophosphate tri- and di-esters in house dust from Adelaide, South Australia: Concentrations, compositions, and human exposure risks

This study aimed to investigate the occurrences of a suite of thirty-one organophosphate tri-esters (tri-OPEs) and six di-esters (di-OPEs) in house dust collected from Adelaide, South Australia. The results demonstrate ubiquitous presence of most OPEs in Adelaide house dust, with median concentration of 40,200 and 5260 ng/g dry weight for ∑tri-OPEs and ∑di-OPEs, respectively. A number of emerging OPEs with chemical structures resembling that of triphenyl phosphate (TPHP), including bisphenol A bis(diphenyl phosphate) (BPA-BDPP), cresyl diphenyl phosphate (CDP), isodecyl diphenyl phosphate (IDDPP), resorcinol-bis(diphenyl)- phosphate (RDP), as well as a suite of isopropylated or tert-butylated triarylphosphate ester isomers (ITPs or TBPPs), were frequently detected with combined levels surpassing that of TPHP. The investigated di-OPEs, predominated by DPHP, consisted of approximately 13% of the ∑tri-OPEs concentrations. Median concentration ratios of diphenyl phosphate (DPHP) and bis(2-ethylhexyl) phosphate (BEHP) to their respective tri-OPEs [i.e., TPHP and tris(2-ethylhexyl) phosphate (TEHP)] were determined to be 1.8 and 2.0, respectively, indicating possible commercial applications for these two di-OPEs. The estimated human intakes of dust-associated OPEs via dust ingestion and dermal contact were much lower than the reference doses. However, the risks of human exposure to OEPs may be complicated by quickly expanding family of OPEs containing various analogues and isomers as well as additional exposure pathways. Therefore, elucidation of human exposure to OPEs and associated risks requires extensive efforts in analytical, environmental, toxicological, and epidemiological investigations.

A review of organophosphate flame retardants and plasticizers in the environment: Analysis, occurrence and risk assessment

Organophosphate esters (OPEs) are used as additives in flame retardants and plasticizers. Due to phase out of several congeners of polybrominated diphenyl ethers (PBDEs), the application of organophosphorus flame retardants (OPFRs) is continuously increasing over the years. As a consequence, large amounts of OPEs enter the environment. Sewage and solid waste (especially e-waste) treatment plants are the important sources of OPEs released to the environment. Other sources include emissions of OPE-containing materials and vehicle fuel into the atmosphere. OPEs are widely detected in air, dust, water, soil, sediment and sludge. To know the pollution situation of OPEs, a variety of methods on their pretreatment and determination have been developed. We discussed and compared the analytical methods of OPEs, including extraction, purification as well as GC- and LC-based determination techniques. Much attention has been paid to OPEs because some of them are recognized highly toxic to biota, and the toxicological investigations of the most concerned OPEs were summarized. Risk assessments showed that the aquatic and benthic environments in some regions are under considerable ecological risks of OPEs. Finally, we pointed out problems in the current studies on OPEs and provided some suggestions for future research.

Broad Exposure of the North American Environment to Phenolic and Amino Antioxidants and to Ultraviolet Filters

The present study provides a comprehensive investigation of three suites of commonly used synthetic additives: phenolic and amino antioxidants and ultraviolet filters. The concentrations of 47 such compounds and their transformation products were measured in 20 atmospheric particle samples collected in Chicago, in 21 Canadian e-waste dust samples, in 32 Canadian and United States' residential dust samples, and in 10 sediment samples collected from the Chicago Sanitary and Ship Canal. Despite their large production volumes in the United States, environmental data on antioxidants and UV filters in North America is limited. These compounds were detected in all the samples, indicating their ubiquitous distribution in the North American environment. The most prevalent compounds were 2,6-di-t-butyl-p-benzoquinone, diphenylamine, 4,4'-di-t-octyl diphenylamine, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-methoxybenzophenone. The e-waste dust contained significantly greater total concentrations of these compounds than the Canadian residential dust, while intermediate levels were detected in the United States residential dust. The sediment samples showed relatively high levels of N,N'-diphenylbenzidine, the source of which is unclear, and some benzotriazole UV filters. Daily intake rates by dust ingestion for these compounds ranged from 1-10 ng/(kg·day) for adults to 10-100 ng/(kg·day) for toddlers. Due to the wide distribution of these compounds in both the ambient and built environments, future research on their potential toxic effects on people and ecosystems is important.

A Review on Citric Acid as Green Modifying Agent and Binder for Wood

Citric acid (CA) can be found naturally in fruits and vegetables, particularly citrus fruit. CA is widely used in many fields but its usage as a green modifying agent and binder for wood is barely addressed. Esterification is one of the most common chemical reactions applied in wood modification. CA contains three carboxyl groups, making it possible to attain at least two esterification reactions that are required for crosslinking when reacting with the hydroxyl groups of the cell wall polymers. In addition, the reaction could form ester linkages to bring adhesivity and good bonding characteristics, and therefore CA could be used as wood binder too. This paper presents a review concerning the usage of CA as a wood modifying agent and binder. For wood modification, the reaction mechanism between wood and CA and the pros and cons of using CA are discussed. CA and its combination with various reactants and their respective optimum parameters are also compiled in this paper. As for the major wood bonding component, the bonding mechanism and types of wood composites bonded with CA are presented. The best working conditions for the CA in the fabrication of wood-based panels are discussed. In addition, the environmental impacts and future outlook of CA-treated wood and bonded composite are also considered.

A method using porous media to deliver gas-phase phthalates rapidly and at a constant concentration: Effects of temperature and media

Phthalates are widely used as additives to consumer products. Many diseases have been shown to be related to the uptake of phthalates. To achieve equilibrium constant phthalate generation for mass transfer and exposure experiments, the present study developed a porous media based method using Teflon generators connected to the media with stainless steel connectors. Carbon sponges with the porosities of 20 ppi (pores per inch), 30 ppi, 40 ppi and honeycomb ceramics of 14 ppi were used as porous media fillers to evaluate the effect of temperature-controlled states, materials, and pore sizes on the generating performance of phthalates. The results showed that 30 ppi carbon sponge fillers at 25.0 ± 0.4 °C performed satisfactorily. DMP, DiBP and DEHP were used as examined phthalates and were generated at 12,800 ± 740 μg/m³, 330 ± 13 μg/m³ and 2.37 ± 0.15 μg/m³, respectively. The times to reach stable concentrations were 4.5 h, 18.5 h and 89.5 h, respectively. The reproducibility of DiBP and DEHP delivery deviated by less than 2.4%. Long-term generating experiments should be performed in the future. The porous media based method could stably deliver gaseous PAEs and tends to be widely used in the research of the adsorption of PAEs on surfaces (airborne particles, settled dust and indoor surfaces) and exposure experiments.

Opportunities for evaluating chemical exposures and child health in the United States: the Environmental influences on Child Health Outcomes (ECHO) Program

The Environmental Influences on Child Health Outcomes (ECHO) Program will evaluate environmental factors affecting children's health (perinatal, neurodevelopmental, obesity, respiratory, and positive health outcomes) by pooling cohorts composed of >50,000 children in the largest US study of its kind. Our objective was to identify opportunities for studying chemicals and child health using existing or future ECHO chemical exposure data. We described chemical-related information collected by ECHO cohorts and reviewed ECHO-relevant literature on exposure routes, sources, and environmental and human monitoring. Fifty-six ECHO cohorts have existing or planned chemical biomonitoring data for mothers or children. Environmental phenols/parabens, phthalates, metals/metalloids, and tobacco biomarkers are each being measured by ≥15 cohorts, predominantly during pregnancy and childhood, indicating ample opportunities to study child health outcomes. Cohorts are collecting questionnaire data on multiple exposure sources and conducting environmental monitoring including air, dust, and water sample collection that could be used for exposure assessment studies. To supplement existing chemical data, we recommend biomonitoring of emerging chemicals, nontargeted analysis to identify novel chemicals, and expanded measurement of chemicals in alternative biological matrices and dust samples. ECHO's rich data and samples represent an unprecedented opportunity to accelerate environmental chemical research to improve the health of US children.

Diethylhexyl phthalate (DEHP) emission to indoor air and transfer to house dust from a PVC sheet

Diethylhexyl phthalate (DEHP) emission to air and transfer to house dust from a polyvinyl chloride (PVC) sheet were quantified for periods of 1, 3, 7, and 14 days using a passive flux sampler (PFS). Japanese Industrial Standards (JIS) test powders class 15 was used as the test house dust in settled weights of 0.3, 1, 3, and 12 mg/cm². DEHP concentrations in the surface air on the PVC sheet were estimated as 2.6-3.3 μg/m³ according to an emission test without dust. Although DEHP transfer rates from the PVC sheet to the house dust decreased over time, the adsorption did not reach an equilibrium state within 14 days. The transfer rates per dust weight increased with decreasing dust weight on the PVC sheet. The transfer rates per PVC sheet area increased nonlinearly with increasing dust weight on the PVC sheet. DEHP emission from a PVC sheet to air was one to three orders of magnitude lower than DEHP transfer from a PVC sheet to dust. In the case of 0.3 mg/cm² of settled house dust for 7 days, the emission rates to air were 35, 15, 9.1, 6.4, and 3.8 μg/m²/h for a diffusion distance of 0.90, 1.85, 2.75, 3.80, and 5.75 mm, respectively, and the transfer rate to dust was 5.3 × 10² μg/m²/h (no difference among the five diffusion distances). Compared to residents who clean the floor every day, exposure to DEHP in house dust could be 10 times higher for residents who clean the floor once every two weeks based on the time-weighted average concentrations in house dust.

Combined exposure to phthalate esters and phosphate flame retardants and plasticizers and their associations with wheeze and allergy symptoms among school children

BACKGROUND

Phthalate esters and phosphate flame retardants and plasticizers (PFRs) are both used as plasticizers and are commonly detected in indoor environments. Although both phthalates and PFRs are known to be associated with children's wheeze and allergic symptoms, there have been no previous studies examining the effects of mixtures of these exposures.

OBJECTIVES

To investigate the association between exposure to mixtures of phthalate esters and PFRs, and wheeze and allergic symptoms among school-aged children.

METHODS

A total of 128 elementary school-aged children were enrolled. Metabolites of 3 phthalate esters and 7 PFRs were measured in urine samples. Parent-reported symptoms of wheeze, rhinoconjunctivitis, and eczema were evaluated using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. In the primary model, we created a phthalate ester and PFR mixture exposure index, and estimated odds ratios (ORs) using weighted quantile sum (WQS) regression and quantile g (qg)-computation. The two highest chemicals according to qg-computation weight %s were combined to create a combination high × high exposure estimate, with ORs calculated using the "low × low" exposure group as the reference category. Concentrations of each metabolite were corrected by multiplying this value by the sex- and body size-Standardised creatinine concentration and dividing by the observed creatinine value. All models were adjusted for sex, grade, dampness index and annual house income.

RESULTS

The odds ratio of rhinoconjunctivitis for the association between exposure to chemical mixtures according to the WQS index positive models was; OR = 2.60 (95% confidence interval [CI]: 1.38-5.14). However, wheeze and eczema of the WQS index positive model, none of the WQS index negative models or qg-computation result yielded statistically significant results. Combined exposure to the two highest WQS weight %s of "high-high" ΣTCIPP and ΣTPHP was associated with an increased prevalence of rhino-conjunctivitis, OR = 5.78 (1.81-18.43) to the "low × low" group.

CONCLUSIONS

Significant associations of mixed exposures to phthalates and PFRs and increased prevalence of rhinoconjunctivitis was found among elementary school-aged children in the WQS positive model. Mixed exposures were not associated with any of allergic symptoms in the WQS negative model or qg-computation approach. However, the combined effects of exposure to two PFRs suggested an additive and/or multiplicative interaction, potentially increasing the prevalence of rhinoconjunctivitis. A further study with a larger sample size is needed to confirm these results.

Occurrence and human health risks of phthalates in indoor air of laboratories

Phthalate acid esters (PAEs) are of serious concern as a human health risk due to their ubiquitous presence in indoor air. In the present study, fifteen PAEs in the indoor air samples from physical, chemical, and biological laboratories in Guangzhou, southern China were analysed using gas chromatography mass spectrometry. Extremely high levels of PAEs of up to 6.39 × 10⁴ ng/m³ were detected in some laboratories. Diisobutyl phthalate (DiBP), di(methoxyethyl) phthalate (DMEP), and di-n-butyl phthalate (DBP) were the dominant PAEs with median levels of 0.48 × 10³, 0.44 × 10³, and 0.39 × 10³ ng/m³, respectively, followed by di-(2-propylheptyl) phthalate (DPHP) and di(2-ethylhexyl) phthlate (DEHP) (median levels: 0.16 × 10³ and 0.13 × 10³ ng/m³, respectively). DMEP and DPHP were found for the first time in indoor air. Principal component analysis indicated that profiles of PAEs varied greatly among laboratory types, suggesting notable variations in sources. The results of independent samples t-tests showed that levels of PAEs were significantly influenced by various environmental conditions. Both the non-carcinogenic and carcinogenic health risks from human exposure to PAEs based on the daily exposure dose in laboratory air were acceptable. Further research should be conducted to investigate the long-term health effects of exposure to PAEs in laboratories.

[Adsorption of Airbone Organophosphorus Flame Retardants on Polished Rice Stored in a House]

In order to clarify the actual situation of indoor pollution to polished rice with organophosphorus flame retardants (PFRs) which are ubiquitous in the indoor environment, the pollution of PFRs to polished rice stored in a house for a week was investigated. The survey covered 64 ordinary families in the Osaka region. We analyzed six typical PFRs in 37 rice samples in 2015, and ten typical PFRs in 27 rice samples in 2016. Polished rice was homogenized with acetone-hexane and defatted by hexane-acetonitrile partition. Quantitative analysis for PFRs was performed by GC-FPD. The detection frequency of PFRs in the rice samples was 35/37 in 2015 and 27/27 in 2016. The highest values were 160 ng/g for TCEP, 500 ng/g for TCIPP and 430 ng/g for TBEP. The concentration ratio of each detected PFR in the polished rice samples was different in each house. In the analysis of 16 polished rice samples which were stored in the home, PFRs were detected in ten samples regardless of the storage methods. PFRs were detected from 12 out of 16 commercial brown rice samples. This result suggested that they were polluted during distribution and storage process of them.

Quantifying the sol-gel process and detecting toxic gas in an array of anchored microfluidic droplets

The detection of toxic gases is becoming an important element in tackling increased air pollution. This has led to the development of gas sensors based on porous solid materials, which are produced using sol-gel chemistry and functionalized to change their optical qualities when in contact with the gas. In this context it is interesting to explore how microfluidics can be used to miniaturize these sensors, to improve their sensitivity and dynamic range, or to multiplex many gas measurements on a single chip. In this article we show how the sol-gel process can be implemented using anchored droplet microfluidics. The sensor material is partitioned into droplets while in the sol phase and maintained using capillary anchors. The ability to hold the droplets in place first allows us to study the sol-gel process. We use an original rheology method, which consists of observing the flows within stationary droplets that are submitted to an external flow, to measure the gelation time of the droplets. These measurements show a gelation time that decreases from 50 minutes to below 10 minutes as the temperature increases from 20 to 50 °C. We also measure the shrinkage of individual gel beads after gelation and find that this syneresis process is nearly finished after about 12 hours, leading to a final bead size that is 50% smaller than the initial droplet. Finally, we show that the beads can be functionalized and used to detect the presence of formaldehyde. These results first provide a new way to observe the physics of the sol-gel process in a well-controlled and quantitative fashion. Moreover they highlight how the coupling of microfluidics and sol-gel chemistry can be used to detect toxic gases, in view of answering the challenges surrounding gas detection in real-world settings.

Household Dust: Loadings and PM10-Bound Plasticizers and Polycyclic Aromatic Hydrocarbons

Residential dust is recognized as a major source of environmental contaminants, including polycyclic aromatic hydrocarbons (PAHs) and plasticizers, such as phthalic acid esters (PAEs). A sampling campaign was carried out to characterize the dust fraction of particulate matter with an aerodynamic diameter smaller than 10 µm (PM10), using an in situ resuspension chamber in three rooms (kitchen, living room, and bedroom) of four Spanish houses. Two samples per room were collected with, at least, a one-week interval. The PM10 samples were analyzed for their carbonaceous content by a thermo-optical technique and, after solvent extraction, for 20 PAHs, 8 PAEs and one non-phthalate plasticizer (DEHA) by gas chromatography-mass spectrometry. In general, higher dust loads were observed for parquet flooring as compared with tile. The highest dust loads were obtained for rugs. Total carbon accounted for 9.3 to 51 wt% of the PM10 mass. Plasticizer mass fractions varied from 5 µg g−1 to 17 mg g−1 PM10, whereas lower contributions were registered for PAHs (0.98 to 116 µg g−1). The plasticizer and PAH daily intakes for children and adults via dust ingestion were estimated to be three to four orders of magnitude higher than those via inhalation and dermal contact. The thoracic fraction of household dust was estimated to contribute to an excess of 7.2 to 14 per million people new cancer cases, which exceeds the acceptable risk of one per million.

Geographical distributions and human exposure of organophosphate esters in college library dust from Chinese cities

Organophosphate esters (OPEs) in indoor dust were closely related to human health. However, OPE contamination in college library dust remained unknown at present. In this study, OPEs were first investigated in 78 indoor dust samples and 26 field blanks of 26 college libraries from 13 prefecture-level cities across China between October and December 2017. The total OPEs fell in the range of 8706-34872 ng/g, and were dominated by tris(2-chloroisopropyl) phosphate (TCIPP), tris(2-chloroethyl) phosphate (TCEP) and tris(2-butoxyethyl) phosphate (TBOEP). OPEs exhibited geography-specific distributions, with high levels in Beijing, Shanghai and Guangzhou. OPEs significantly correlated with population density and gross domestic product (p < 0.01), indicating the distinct effect of these two indicators on OPE pollution. Analysis of pollution source indicated volatilization and abrasion as main emission pathways of OPEs from OPEs-added products to dust. The daily exposure doses (DEDs) of OPEs via dust ingestion, inhalation and dermal contact were similar for male and female students, ranging from 1.35 to 5.92 ng/kg-bw/day during study time in libraries (25% of day). High DEDs were found in Beijing, shanghai and Guangzhou, indicating high exposure risk of OPEs to college students in large cities. The non-carcinogenic and carcinogenic risks of OPEs to college students were quantitatively evaluated based on the oral reference dose and cancer slope factor of OPEs recently updated by USEPA, and all much lower than the threshold risk values. However, the potential risk may occur if exposure to OPEs is high in other microenvironments over remaining hours of the day.

Pollution characteristics of 15 gas- and particle-phase phthalates in indoor and outdoor air in Hangzhou

Phthalate esters (PAEs), typical pollutants widely used as plasticizers, are ubiquitous in various indoor and outdoor environments. PAEs exist in both gas and particle phases, posing risks to human health. In the present study, we chose four typical kinds of indoor and outdoor environments with the longest average human residence times to assess the human exposure in Hangzhou, including newly decorated residences, ordinary residences, offices and outdoor air. In order to analyze the pollution levels and characteristics of 15 gas- and particle-phase PAEs in indoor and outdoor environments, air and particulate samples were collected simultaneously. The total PAEs concentrations in the four types of environments were 25,396, 25,466.8, 15,388.8 and 3616.2 ng/m³, respectively. DEHP and DEP were the most abundant, and DMPP was at the lowest level. Distinct variations in the distributions of indoor/outdoor, gas/particle-phase and different molecular weights of PAEs were observed, showing that indoor environments were the main sources of PAEs pollution. While most PAEs tended to exsit in indoor sites and gas-phase, the high-molecular-weight chemicals tended to exist in the particle-phase and were mainly found in PM_2.5. PAEs were more likely adsorbed by small particles, especially for the indoor environments. There existed a good correlation between the particle matter concentrations and the PAEs levels. In addition, neither temperature nor humidity had obvious effects on the distributions of the PAEs concentrations.

Emission characteristics of diethylhexyl phthalate (DEHP) from building materials determined using a passive flux sampler and micro-chamber

Emission rates of diethylhexyl phthalate (DEHP) from building materials, such as vinyl floorings and wall paper, determined using a passive flux sampler (PFS) were constant over the week-long measurement period. Emission rates for vinyl floorings and wallpaper were linearly correlated to the inverse of diffusion distance, which corresponds to the internal depth of the PFS. Surface-air DEHP concentrations (y0) were estimated as 1.3-2.3 μg/m3 for materials having a boundary layer molecular diffusion rate-limiting step. The partition coefficient (Kmaterial-air) was estimated as 3.3-7.5 × 1010 for these materials. Additionally, emission rates of DEHP from same building materials determined using a micro-chamber were 4.5-6.1 μg/m2/h. Mass transfer coefficients in the micro-chamber (hm) were estimated by comparing the results using the PFS and micro-chamber, and these were 1.1-1.2 × 10-3 and 8.1 × 10-4 m/s for vinyl floorings (smooth surface) and wallpaper (rough surface), respectively. The thickness of boundary layer on the surface of building materials in the micro-chamber were estimated to be 2.5-2.6 and 3.7 mm for vinyl floorings and wallpaper, respectively.

Reduction of hazardous chemicals in Swedish preschool dust through article substitution actions

Consumer goods and building materials present in the preschool environment can be important sources of hazardous chemicals, such as plasticizers, bisphenols, organophosphorus and brominated flame retardants, poly- and perfluoroalkyl substances, which may pose a health risk to children. Even though exposure occurs via many different pathways, such as food intake, inhalation, dermal exposure, mouthing of toys etc., dust has been identified as a valuable indicator for indoor exposure. In the present study, we evaluate the efficiency of product substitution actions taken in 20 Swedish preschools from the Stockholm area to reduce the presence of hazardous substances in indoor environments. Dust samples were collected from elevated surfaces in rooms where children have their everyday activities, and the concentrations found were compared to the levels from a previous study conducted in 2015 at the same preschools. It was possible to lower levels of hazardous substances in dust, but their continued presence in the everyday environment of children was confirmed since bisphenol A, restricted phthalates and organophosphate esters were still detectable in all preschools. Also, an increase in the levels of some of the substitutes for the nowadays restricted substances was noted; some of the alternative plasticizers to phthalates, such as DEHA and DEHT, were found with increased concentrations. DINP was the dominant plasticizer in preschool dust with a median concentration of 389 μg/g, while its level was significantly (p = 0.012) higher at 716 μg/g in preschools with polyvinyl chloride (PVC) flooring. PBDEs were now less frequently detected in dust and their levels decreased 20% to 30%. This was one of the few times that PFAS were analyzed in preschool dust, where 6:2 diPAP was found to be most abundant with a median concentration of 1140 ng/g, followed by 6:2 PAP 151 ng/g, 8:2 diPAP 36 ng/g, N-Et-FOSAA 18 ng/g, PFOS 12 ng/g, PFOA 7.7 ng/g and PFNA 1.1 ng/g. In addition, fluorotelomer alcohols were detected in 65-90% of the samples. Children's exposure via dust ingestion was evaluated using intermediate and high daily intake rates of the targeted chemicals and established health limit values. In each case, the hazard quotients (HQs) were < 1, and the risk for children to have adverse health effects from the hazardous chemicals analyzed in this study via dust ingestion was even lower after the product substitution actions were taken in preschools.

Semi-volatile organic compounds in infant homes: Levels, influence factors, partitioning, and implications for human exposure

While infants are developing, they are easily affected by toxic chemicals existing in their environments, such as semi-volatile organic compounds (SVOCs): phthalates, polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), and organophosphate esters (OPEs). However, the specific living environment of infants, including increased plastic products and foam floor mats, may increase the presence of these chemicals. In this study, 68 air, dust, and window film samples were collected from homes, with 3- to 6-month-old infant occupants, to analyze phthalates, PAHs, PBDEs, and OPEs. High detection rates and concentrations suggest that these SVOCs are widespread in infant environments and are associated with cooking methods, smoking habits, the period of time after decoration, and room floors. The partitioning behavior of SVOCs indicates that the logarithms of the dust/gas-phase air partition coefficient (logK_D) and the window film/gas-phase air partition coefficient (logK_F) in homes are not at an equilibrium state when the logarithm of the octanol/air partition coefficient (logK_OA) is less than 8 or greater than 11. Considering the 3 exposure routes, ingestion and dermal absorption have become the main routes of infant exposure to phthalates and OPEs, and ingestion and inhalation have become the dominant routes of exposure to PAHs and PBDEs. The total carcinogenic risk of SVOCs, which have carcinogenic toxicities, via ingestion and dermal absorption for infants in homes exceeds the acceptable value, suggesting that the current levels of these SVOCs in homes might pose a risk to infant health.

Concentrations of selected chemicals in indoor air from Norwegian homes and schools

Both building materials and consumer products have been identified as possible sources for potentially hazardous substances like phthalates, polychlorinated biphenyls (PCBs), organophosphorous flame retardants (OPFRs), polybrominated diphenyl ethers (PBDEs) and short chain chlorinated paraffins (SCCPs) in indoor air. Thus, indoor air has been suggested to contribute significantly to human exposure to these chemicals. There is lack of data on the occurrence of several of the aforementioned chemicals in indoor air. Therefore, indoor air (gas and particulate phase) was collected from 48 households and 6 classrooms in two counties in Norway. In both the households and schools, median levels of low molecular weight phthalates (785 ng/m³), OPFRs (55 ng/m³) and SCCPs (128 ng/m³) were up to 1000 times higher than the levels of PCBs (829 pg/m³) and PBDEs (167 pg/m³). Median concentrations of dimethyl phthalate (DMP), diethyl phthalate (DEP), di-isobutyl phthalate (DiBP) and SCCPs were 3-6 times higher in households compared to schools. The levels of OPFRs, PCBs and PBDEs were similar in households and schools. In univariate analysis, the indoor concentrations of different environmental chemicals were significantly affected by location of households (OPFRs), airing of living room (some PCBs and PBDEs), presence of upholstered chair/couch (OPFRs), pet animal hold (some PBDEs) and presence of electrical heaters (selected PCBs and PBDEs). Significant correlations were also detected for the total size of households with OPFRs, frequency of vacuuming the living room with selected PCBs and PBDEs, frequency of washing the living room with selected PCBs and the total number of TVs in the households with selected phthalates and SCCPs. Finally, intake estimates indicated that indoor air contributed more or equally to low molecular weight phthalates and SCCPs exposure compared to food consumption, whereas the contribution from indoor air was smaller than the dietary intake for the other groups of chemicals.

Human exposure to phthalates from house dust in Bangkok, Thailand

The study determined concentrations of and estimated human exposure to house dust-ingested phthalates from 99 homes in Bangkok, Thailand. Phthalates in dust collected using a handheld vacuum cleaner was analyzed by gas chromatography/mass spectrometry revealing a median content of 3,477 µg g^-1, range 753-13,810 µg g^-1, with di-2-ethylhexylphthalate (DEHP) having the highest level (median = 1,739 µg g^-1, range 467-8,172 µg g^-1) followed by di-iso-nonyl phthalate (DiNP) (median = 611 µg g^-1, range 15.2-11,052 µg g^-1). DEHP in house dust from multi-family apartments with polyvinyl (PVC) floor material (n = 34), multi-family apartments without PVC floor material (n = 55) and single family houses without PVC floor material (n = 10) was median and range 3,009 and 568-6,898; 1,479 and range 467-8,172 and 1,207 µg g^-1 and 611-3518 µg g^-1, respectively. At high-end house dust DEHP level, preschool children in all three types of homes were exposed above US Environment Protection Agency reference dose (20 µg g^-1). The results suggest phthalate-containing house products constitute a likely major source of phthalates in indoor home environment and pose a potential health risk to residents, particularly preschool children, in Bangkok.

Sources and dynamics of semivolatile organic compounds in a single-family residence in northern California

Semivolatile organic compounds (SVOCs) emitted from building materials, consumer products, and occupant activities alter the composition of air in residences where people spend most of their time. Exposures to specific SVOCs potentially pose risks to human health. However, little is known about the chemical complexity, total burden, and dynamic behavior of SVOCs in residential environments. Furthermore, little is known about the influence of human occupancy on the emissions and fates of SVOCs in residential air. Here, we present the first-ever hourly measurements of airborne SVOCs in a residence during normal occupancy. We employ state-of-the-art semivolatile thermal-desorption aerosol gas chromatography (SV-TAG). Indoor air is shown consistently to contain much higher levels of SVOCs than outdoors, in terms of both abundance and chemical complexity. Time-series data are characterized by temperature-dependent elevated background levels for a broad suite of chemicals, underlining the importance of continuous emissions from static indoor sources. Substantial increases in SVOC concentrations were associated with episodic occupant activities, especially cooking and cleaning. The number of occupants within the residence showed little influence on the total airborne SVOC concentration. Enhanced ventilation was effective in reducing SVOCs in indoor air, but only temporarily; SVOCs recovered to previous levels within hours.

Linking past uses of legacy SVOCs with today's indoor levels and human exposure

Semivolatile organic compounds (SVOCs) emitted from consumer products, building materials, and indoor and outdoor activities can be highly persistent in indoor environments. Human exposure to and environmental contamination with polychlorinated biphenyls (PCBs) was previously reported in a region near a former PCB production facility in Slovakia. However, we found that the indoor residential PCB levels did not correlate with the distance from the facility. Rather, indoor levels in this region and those reported in the literature were related to the historic PCB use on a national scale and the inferred presence of primary sources of PCBs in the homes. Other SVOCs had levels linked with either the activities in the home, e.g., polycyclic aromatic hydrocarbons (PAHs) with wood heating; or outdoor activities, e.g., organochlorine pesticides (OCPs) with agricultural land use and building age. We propose a classification framework to prioritize SVOCs for monitoring in indoor environments and to evaluate risks from indoor SVOC exposures. Application of this framework to 88 measured SVOCs identified several PCB congeners (CB-11, -28, -52), hexachlorobenzene (HCB), benzo(a)pyrene, and γ-HCH as priority compounds based on high exposure and toxicity assessed by means of toxicity reference values (TRVs). Application of the framework to many emerging compounds such as novel flame retardants was not possible because of either no or outdated TRVs. Concurrent identification of seven SVOC groups in indoor environments provided information on their comparative levels and distributions, their sources, and informed our assessment of associated risks.

A review on organophosphate Ester (OPE) flame retardants and plasticizers in foodstuffs: Levels, distribution, human dietary exposure, and future directions

Given the ongoing studies on the adverse effects of organophosphate ester (OPE) flame retardants and plasticizers on human health, there is an increasing scientific interest in the risk of exposure to OPEs via dietary intake. Using peer-reviewed literature published up to 2018, this review surveyed and compiled the available and reported data on the concentrations and distributions of 30 OPEs based on their occurrence in various food samples from around the world. Regardless of sampling locations or food categories, 22 OPEs were detectable in at least one of analyzed sample, and there were clear variations in OPE levels among samples from different locations or food categories. For instance, cereals and fats/oils were the most contaminated by OPEs in China and Belgium, whereas fats/oils and desserts were the main polluted products in Sweden. In contrast, vegetables, fruits, fluid dairy products, and cereals were reported as the primary categories of food polluted by OPEs in Australia. Animal-based food categories such as eggs, fish and meat were the least contaminated, whereas the highest median OPE concentrations were found in meat and fish from the United State. The levels and distribution patterns of OPEs in foodstuffs demonstrated a tremendous difference even when collected from the same country and the same food item. Rice from China had the highest tris(2‑chloroethyl) phosphate (TCEP, mean: 29.8 ng/g dw) levels, whereas 2‑ethylhexyl‑diphenyl phosphate (EHDPP, mean: 4.17 ng/g ww), triphenyl phosphate (TPHP, mean: 26.14 ng/g ww), tris(2-chloroisopropyl) phosphate (TCIPP, mean: 0.87 ng/g ww) and tributyl phosphate (TNBP, median: 0.55 ng/g ww) concentrations were the highest in the same food category from Sweden, Belgium, Australia, and the United States, respectively. These discrepancies may be due to a variety of reasons such as differences in OPE physico-chemical properties, extent of usage, uptake, metabolic pathways, industrial food manufacturing processes, OPE level differences as a function of habitat, and accumulation and degradability of OPEs in different species. It is worth noting that, due to its worldwide usage in food packaging materials, EHDPP was more prominently found in processed food compared to non-processed food. Based on reported OPE levels in various foods, this review conducted a preliminary assessment of human exposure to OPEs through dietary intake, which suggested that the OPE estimated daily intake (EDI) for humans was around 880 ng/kg bw/day (95th percentile). This value was well below the corresponding OPE health reference dose given by the U.S. EPA (≥15,000 ng/kg bw/day). Even so, dietary exposure to OPEs via food intake may be not negligible based on some important factors such as dilution effects, cooking processes, and the contribution of as yet unknown means of OPE exposure. Overall, this review highlights several gaps in our understanding of OPEs in foodstuffs: 1) the investigation of contamination levels of OPEs in foodstuffs should be extended to other regions, especially North America and European countries, where OPEs are widely used and frequently detected in environmental samples, and 2) newly identified OPE derivatives/by-products, e.g., OP diesters and hydroxylated metabolites, which have been reported as end-products of OPE enzymatic metabolism or degradation through aqueous hydrolysis, and which may co-exist with parent OPEs, could also be screened with precursor OPEs in foodstuffs in future studies.

Organophosphate flame retardants in college dormitory dust of northern Chinese cities: Occurrence, human exposure and risk assessment

Organophosphate flame retardants (OPFRs) are widely added to consumer products and building materials, which may pose potential health risk to humans. But information on their contamination and human exposure in the indoor environment especially dormitories in northern China is rare. In this study, twelve OPFRs were investigated in college dormitory dust that collected from Harbin, Shenyang, and Baoding, in northern China. Indoor dust samples were also collected from homes and public microenvironments (PMEs) in Harbin for comparison. The median ∑OPFR concentrations in dormitory dust in Shenyang samples (8690 ng/g) were higher than those in Baoding (6540 ng/g) and Harbin (6190 ng/g). The median ∑OPFR concentrations in home dust (7150 ng/g) were higher than in dormitory and PME dust (5340 ng/g) in Harbin. Tris(2‑chloroethyl) phosphate (TCEP) and tris (2-chloroisopropyl) phosphate (TCIPP) were the most abundant chlorinated OPFRs, while triphenyl phosphate (TPHP) and tris(2‑butoxyethyl) phosphate (TBOEP) were the dominant non-chlorinated OPFRs. The daily intakes of ∑OPFR were estimated, with the median values for female students (2.45 ng/kg-day) higher than those for male students (2.15 ng/kg-day) while were similar to adults (2.45 ng/kg-day) in homes. The estimated daily intakes (EDI) of these OPFRs from indoor dust in Harbin were all below the recommended values. The calculated non-carcinogenic hazard quotients (10^-8-10^-3) from OPFRs were much lower than the theoretical risk threshold. Meanwhile, carcinogenic risk (CR) of tri‑n‑butyl phosphate (TNBP), TCEP, tris(2‑ethylhexyl) phosphate (TEHP), and tris(1,3‑dichloroisopropyl) phosphate (TDCIPP) were also estimated. The highest carcinogenic risk of TCEP for gender-specific and age-specific category range from 1.75 × 10^-7 to 2.46 × 10^-7 from exposure to indoor dust indicated a low potential carcinogenic risk for human exposure.

Co-Existence of Organophosphate Di- and Tri-Esters in House Dust from South China and Midwestern United States: Implications for Human Exposure

Despite numerous studies on the contamination of organophosphate triesters (tri-OPEs) in indoor environments, organophosphate diesters (di-OPEs) have rarely been investigated. The present study aimed to investigate whether di-OPEs coexist with tri-OPEs in house dust collected from Guangzhou ( n = 30), South China and the city of Carbondale ( n = 17) located in the Midwestern United States (U.S.). Median concentrations of bis(2-butoxyethyl) phosphate (BBOEP), bis(1-chloro-2-propyl) phosphate (BCIPP), bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), bis(2-ethylhexyl) phosphate (BEHP), bis(2-methylphenyl phosphate) (BMPP), and diphenyl phosphate (DPHP) were determined to be 15.9, < LOQ, 33.6, 654, 9.5, and 605 ng/g in South China house dust, and 1580, 90.6, 234, 867, 4.0, and 6500 ng/g in Midwestern U.S. dust, respectively. The total concentrations of di-OPEs (referred to Σ_diOPEs) constituted an average of 22.9% and 21.3% of the total concentrations of tri-OPEs in dust from these two locations, respectively. Median concentration ratios of DPHP and BEHP to their respective tri-OPEs (i.e., TPHP and TEHP) were determined to be 1.1 and 1.0 in South China dust and 3.7 and 1.4 in Midwestern U.S. dust, respectively, indicating possible commercial applications for these two di-OPEs. Correlative analyses reveal chemical- and region-specific relationships between di-OPEs and their respective tri-OPEs, suggesting that the relative importance of different sources (e.g., direct commercial use, impurity in tri-OPE formulas, and tri-OPE degradation) could vary for different di-OPEs. Our findings demonstrate wide occurrences of di-OPEs in an indoor environment from the studied locations and raise concerns on human exposure to dust associated di-OPEs. Future studies are needed to explore more possible di-OPEs in indoor environments and elucidate their sources, human exposure pathways, and toxicokinetics.

Biomonitoring of organophosphate flame retardants and plasticizers in children: Associations with house dust and housing characteristics in Japan

Indoor environments contain a wide range of new chemicals such as phosphate flame retardants and plasticizers (PFRs). Despite recent epidemiological evidence suggesting that children might be affected by widespread exposure to PFRs, questions remain about the various exposure pathways to these chemicals. Therefore, the aim of this study was to investigate exposure to PFRs by measuring the concentrations a set of urinary metabolites for schoolchildren from Japan (n = 128) and associating them with house dust concentrations and housing characteristics. Detectable concentrations of both diaryl and dialkyl phosphates (DAPs) and hydroxylated metabolites (HO-PFRs) were found in urine samples of almost all children. 2-Hydroxyethyl bis(2-butoxyethyl) phosphate (BBOEHEP) was the most frequently detected metabolite (98%) followed by 1-hydroxy-2-propyl bis(1-chloro-2-propyl) phosphate (BCIPHIPP, 95%) and tris(chloroethyl) phosphate (TCEP). Next to BBOEHEP, two other metabolites of tris(2-butoxyethyl) phosphate (TBOEP) were also frequently detected. Significant correlations of moderate strength were found between parent compounds detected in high concentrations in house dust (TBOEP, tris(2-chloroisopropyl) phosphate (TCIPP)) and their corresponding metabolites, suggesting that dust is a primary exposure source for these PFRs. Several personal and housing characteristics, such as gender, income, and the use of PVC and ventilation were associated with metabolite concentrations in multivariate linear regression. Overall, this study showed that Japanese schoolchildren are exposed to a wide range of PFRs.

Concentrations of brominated and phosphorous flame retardants in Finnish house dust and insights into children's exposure

Brominated and phosphorous flame retardants (BFRs, PFRs) are added to household and consumer products to reduce their flammability. Some FRs are persistent in the environment and may have adverse health effects. As exposure indoors contributes significantly to total exposure, we wanted to estimate the exposure of children (3 years of age) through dust ingestion, inhalation, and dermal absorption. We measured 17 BFRs and 10 PFRs in indoor dust, predicted their respective concentrations in the indoor air and assessed children's exposure. Among the BFRs, decabromodiphenyl ether (BDE-209) had highest median level in the dust (411 ng/g) followed by decabromodiphenyl ethane (DBDPE, 119 ng/g) and bis-ethylhexyl tetrabromophthalate (BEH-TEBP, 106 ng/g). Among the PFRs, trisbutoxyethyl phosphate (TBOEP) had the highest concentration (11100 ng/g) followed by tris(2-chloroisopropyl) phosphate (TCIPP, 1870 ng/g) and triphenyl phosphate (TPHP, 773 ng/g). FR concentration in air predicted from dust concentrations were within the interquartile range of experimental data for 10/13 of BFRs and 4/8 of PFRs compared. Dust ingestion was the major route of exposure (75-99%) for higher molecular weight BFRs, TBOEP and phenyl based PFRs (73-77%). Inhalation was important for volatile BFRs like pentabromobenzene (PBB 71%) and pentabromotoluene (PBT 52%) and dermal exposure for volatile chlorinated PFRs (TCEP 84%, TCIPP 77%). Margins of Exposure (MoE) were calculated as the ratio of total exposure to oral Reference Dose (RfD). MoEs were lowest for TCEP (220), TBOEP (240) and TCIPP (830), and > 1000 for all other FRs. These MoEs imply no risk for Finnish children by the studied FRs.

Biotransformation and oxidative stress responses in rat hepatic cell-line (H4IIE) exposed to organophosphate esters (OPEs)

Organophosphate esters (OPEs) are frequently used as replacements for the banned polybrominated diphenyl ether (PBDEs). Since OPEs are structurally similar to organophosphate pesticides, exposure and toxicity of these compounds is of significant societal and scientific interest. Cytotoxicity (MTT), biotransformation (cyp1a1) and oxidative stress responses (gpx1, gr, gsta2, cat) were investigated in H4IIE cells exposed for 48 h to four different OPEs (tributyl phosphate (TBP), tris(2-butoxyethyl) phosphate (TBOEP), tris-(2-chloroethyl) phosphate (TCEP) and triphenyl phosphate (TPP)). MTT assay revealed a dose-dependent decrease of cell viability following exposure to TBP, TBOEP, TCEP and TPP. Cells treated with TBP and TBOEP exhibited significant increase of cyp1a1 at the highest tested concentration, at transcriptional and enzymatic (MROD) levels. Significant increases of oxidative stress markers were observed after exposure to TBP and TBOEP. On the other hand, cells treated with TCEP and TPP showed opposite trends between cyp1a1 mRNA and enzymatic activities. Furthermore, exposure to TCEP increased gst and cat especially at the highest concentration tested, whereas TPP produced significant changes only for gr and cat at the highest concentration. In conclusion, OPEs produced compound and concentration-specific effects on biotransformation and oxidative stress processes. Overall, our results suggest the participation of multiple mechanisms of detoxification in defense of OPEs exposure with different modes of action depending on their chemical structure.

Indoor Air Quality and Health in Newly Constructed Apartments in Developing Countries: A Case Study of Surabaya, Indonesia

In times of rapid urbanization, increasing usage of chemicals in buildings, and energy saving measures, the topic of indoor air quality (IAQ) demands reinforced attention. Nevertheless, especially in developing countries with urgent building construction needs, IAQ has hardly been examined. This study investigates the condition of IAQ and health of occupants in newly constructed high-rise apartments in contrast to traditional detached houses (Kampongs) in Surabaya, Indonesia. Information on building attributes, cleaning and ventilation behavior, interior sources, personal characteristics and health, especially multiple chemical sensitivity (MCS), was collected through 471 questionnaires. In addition, 76 measurements of TVOCs, formaldehyde and 30 measurements of mold risk were carried out. The results showed that the share of people in apartments with a very suggestive risk of MCS was twice as high as that in Kampongs (17.6% vs. 6.7%). Correlation analysis suggested that for both residential types, health problems, negative smell or perception of IAQ, and higher levels of stress determined higher degrees of MCS. For IAQ, high concentrations of formaldehyde and TVOCs were measured in apartments and corresponded to higher MCS risk, whereas severe mold issues were predicted in Kampongs. This study suggests major shortcomings in the indoor environment in newly constructed apartments for the physical and the mental health of occupants.

Organophosphate flame retardants in the indoor and outdoor dust and gas-phase of Alexandria, Egypt

Little is known about the presence of organophosphate flame retardants (OPFRs) as a substitute for polybrominated diphenyl ethers in developing countries. This study investigated - for the first time - concentrations, sources and exposure levels of OPFRs in the indoor and outdoor environments of Alexandria, Egypt, in dust and gas-phase samples. Passive samplers were deployed (n = 78) to determine gaseous concentrations, and various dust samples were collected from apartments (n = 25), working places (n = 14), cars (n = 18), and outdoors (OD, n = 30). Indoor concentrations (air: 7.0-64 pg/m³; dust: 150-1850 ng/g) were significantly higher than outdoor (2.0-16 pg/m³ and 83-475 ng/g) concentrations. Tris-1,3-dichloropropyl phosphate (TDCIPP), tris(1-chloro-2-propyl) phosphate (TCIPP), tri (2-butoxyethyl) phosphate (TBOEP) and triphenyl phosphate (TPHP) dominated in all samples with more indoor variabilities. Profiles of OPFRs in OD and floor dust (collected from carpets and floors) were similar but differed from elevated fine dust (collected 1 m above the floor from all available surfaces), possibly due to the influence of carryover of OD by shoes. Despite the high uncertainty in dust - air partitioning coefficients, log transformed values showed significant linear relationships with log octanol - air-partitioning coefficients in all microenvironments, indicating an equilibrium partitioning between dust and vapor. Exposure assessment indicated the importance of the dermal exposure route for adults and ingestion route for children.

Comparison of rates of direct and indirect migration of phosphorus flame retardants from flame-retardant-treated polyester curtains to indoor dust

In this study, the pathways for migration of phosphorus flame retardants (PFRs), tris(1,3-dichloroisopropyl) phosphate (TDCPP) and tricresyl phosphate (TCsP) which were detected from curtains often, from flame-retardant-treated polyester curtains to indoor dust were investigated. Two possible migration pathways were compared quantitatively: (1) an indirect pathway in which the PFRs in the curtains first evaporate from the curtains and are then adsorbed onto indoor dust and (2) a direct pathway in which the PFRs are directly transferred to dust placed on the curtains. The contribution of the indirect pathway was evaluated by means of emission cell tests, which showed that the area-specific emission rates from curtains treated with PFRs were 0.044 (TDCPP, Curtain 5), 0.17 (TDCPP, Curtain 8), and 0.060 (TCsP, Curtain 12) μg m^-2 h^-1 at 20 °C (averaged during 24 h). The contribution of the direct pathway was evaluated by measurement of the time dependence of PFR concentrations on the indoor dust placed on the curtains. These measurements indicated that PFR concentrations on the dust increased with time and that the direct migration rates of PFRs from curtains treated with PFRs were 4.4 (TDCPP, Curtain 5), 12 (TDCPP, Curtain 8), and 7.0 (TCsP, Curtain 12) μg m^-2 h^-1 at 20 °C (averaged during 24 h), or 71-120 times the indirect migration rate. This result suggests that the direct pathway can be expected to predominate.

Flows, stocks, and emissions of DEHP products in Japan

The usage of products containing Bis (2‑ethylhexyl) Phthalate (DEHP) is widespread, mainly through the great variety of PVC products. However, DEHP has become a worldwide concern, due to the potential health and environmental risks it presents. In this study, material flow analysis and emission estimations for DEHP products in Japan, from 1948 to 2030, were performed. Moreover, an evaluation of the potentially damaging impacts on human health and the environment was completed through a lifecycle impact assessment approach. The analysis focused on three representative lifecycle phases - Production, Use and Treatment and Disposal. The peak flows of DEHP from Production to the Use phase were in 1996 with 285,300 tons for shipment and the stocks peaked in 2001 with 1,981,908 tons. Accordingly, in 2006 the peak of DEHP waste to the Treatment and disposal phase was 190,792 tons. The primary emissions were observed in the Use phase, due to the large stocks, with DEHP mostly being released to the pedosphere. The total emissions from the Use phase reached the maximum of 48,960 tons in 2000, whereas in the Production and Treatment and disposal phase it was 248 tons and 15 tons, respectively. Subsequently, concerning the evaluation of impacts, the damage to the human health was the most widespread impact, totaling 13,782 disability-adjusted life years (DALYs), compared with the damage to the ecosystems, with 0.12 species·year. Furthermore, the risk-risk tradeoffs between the lifecycle phases were clarified throughout the years.

Organophosphate esters in house dust: A comparative study between Canada, Turkey and Egypt

Organophosphate esters (OPEs) are commonly used as flame retardants (FRs) and plasticizers. The usage of OPEs has increased recently due to the ban of several brominated flame retardants, but information on levels in the environment, including the indoor environment is still limited. We investigated the occurrence and distribution of 12 OPEs in urban house dust from Vancouver, Canada; Istanbul, Turkey; and Cairo, Egypt. The median ∑OPE concentration was 41.4 μg/g in the Vancouver samples while median levels in Istanbul and Cairo were significantly lower. The median composition profiles of OPEs in Vancouver and Cairo were dominated by tris (2-butoxyethyl) phosphate (TBOEP), accounting for 56 and 92% of total OPEs respectively while it showed a detection frequency of only 14% in Istanbul. Tris (2-chloropropyl) phosphate (TCPP) was the most abundant chlorinated OPE representing 20 and 36% of the total OPEs in Vancouver and Istanbul respectively, but was below the detection limit in the Cairo dust samples. Consistent with other studies, ΣOPE concentrations were ~1 to 2 orders of magnitude higher than PBDEs and currently used flame retardants in the same dust samples. The mean estimated daily intakes (EDI) of ΣOPE from dust were 115, 38 and 9 ng/kg/bw/day in Vancouver, Cairo and Istanbul respectively for toddlers where adults were ~10 times lower. The total toddler OPE intake ranged from 115 to 2900, 38 to 845 and from 9 to 240 ng/kg bw/day across the three cities. TBOEP had the largest contribution to the EDI in both toddler and adults, where toddler TBOEP exposures via dust represented 4% to 80%, 2% to 44% and 0.1% to 6% of the Reference Doses (RfD) in the mean and high intake scenarios for toddlers in Vancouver, Cairo and Istanbul respectively.

Distributions of organophosphate flame retardants (OPFRs) in three dust size fractions from homes and building material markets

The distributions of organophosphate flame retardants (OPFRs) in various size fractions of indoor dust samples from homes (H; n = 18) and building material markets (B; n = 7) in the Rhine/Main region of Germany were investigated. Three particle size fractions (F1: 150-200 μm, F2: 63-150 μm, and F3: <63 μm) and bulk dust (BD) subsamples (<200 μm) of each sample were analyzed for 10 OPFRs. On average, the total OPFR concentrations (∑₁₀OPFR) in bulk dust and all three size fractions from building material markets were 133, 153, 196, and 88.0 μg/g in subsamples B-BD, B-F1, B-F2, and B-F3. These concentrations were at least five times higher than those in bulk dust and all three size fractions from homes, with values of 19.3, 17.2, 19.5, and 18.7 μg/g for subsamples H-BD, H-F1, H-F2, and H-F3, respectively. Tris(2-chloroisopropyl)phosphate (TCIPP) was the dominant congener in dust from building material markets, contributing over 91% to the ∑₁₀OPFR of B-BD and all particle size fractions. Meanwhile, both tris(2-butoxyethyl)phosphate (TBOEP) and TCIPP were abundant in dust from homes, respectively contributing 28%-41% and 31%-43% to the ∑₁₀OPFR of H-BD and all particle size fractions. Most of the OPFR concentrations showed no consistent trend with particle size. However, TCIPP was more likely to be enriched in F2. Microscopic examination indicated that TCIPP in indoor dust mainly originated from abraded fragments of commercial products. In contrast, TBOEP accumulated in F3, related to direct transfer of floor-care products to fine dust particles. The concentrations of OPFRs were not significantly correlated with total organic carbon contents in any particle size fraction. However, evaluation of their mass contributions showed that more than 85% of OPFRs accumulated in particles smaller than 150 μm, indicating that this particle size fraction is most suitable for monitoring of OPFRs.

Differential occurrence, profiles and uptake of dust contaminants in the Barcelona urban area

Dust is a complex but increasingly used matrix to assess human exposure to organic contaminants both in indoor and outdoor environments. Knowledge concerning the effects of organic pollution towards health outcome is crucial. This study is aimed to determine the presence of legacy compounds (DDTs and polychlorinated biphenyls, PCBs), compounds used in recent times (organophosphorous flame retardants, organophosphorous pesticides, BPA, phthalates and alkylphenols) and compounds originated from combustion processes (polycyclic aromatic hydrocarbons, PAHs) as well as nicotine in indoor environments along the metropolitan area of Barcelona. Monitored sites include public areas with high turnout (high schools, museums samples) and libraries and private spaces (houses and cars). Almost all compounds (57 over the 59 targeted) were found in each dust sample and libraries and schools were the most contaminated, with concentrations of ∑phthalates and ∑OPFRs up to 15 and 10 mg g^-1, respectively. One-way ANOVA tests, Tukey contrasts and principal component analysis (PCA) revealed that sampling place influenced the observed contamination profiles and public and private environments were clearly differentiated. Finally, based on the concentrations detected, a deterministic calculation was performed to estimate the total daily intakes of each compound via dust. This information was used to evaluate the human exposure for toddlers, teenagers and adult workers. Consistently, the highest concentrations coming from plasticisers and flame retardants gave the major exposure rates. As expected, toddlers were the most affected group followed by museum and library workers, although the levels were below the reference doses.

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.

Association of filaggrin gene mutations and childhood eczema and wheeze with phthalates and phosphorus flame retardants in house dust: The Hokkaido study on Environment and Children's Health

BACKGROUND AND AIM

Exposure to phthalates and phosphorus flame retardants (PFRs) is considered to be a risk factor for asthma and allergies. However, little is known about the contribution of loss-of-function mutations in the gene encoding filaggrin (FLG) gene, which are considered to be predisposing factors for eczema and asthma, to these associations. We investigated the associations between exposure to phthalates and PFRs in dust and eczema/wheeze among Japanese children, taking into consideration loss-of-function mutations in FLG.

METHODS

This study was part of the Hokkaido study on Environment and Children's Health. Seven phthalates and 11 PFRs in household dust were measured by gas chromatography-mass spectrometry. Eczema and wheeze were assessed in children aged 7 years using the International Study of Asthma and Allergies in Childhood questionnaire. Eight FLG mutations previously identified in the Japanese population were extracted from cord blood samples. Children with one or more FLG mutations were considered to be positive for FLG mutations. The study included 296 children who had complete data (birth records, FLG mutations, first trimester and 7 years questionnaires, and phthalate/PFR levels). Odds ratios (ORs) and 95% confidential intervals (CIs) of eczema and wheeze were calculated for log-transformed phthalate/PFR levels by logistic regression. We also performed stratified analyses based on FLG mutations.

RESULTS

The prevalence rates of eczema and wheeze were 20.6% and 13.9%, respectively. Among children without any FLG mutations, tris (1, 3-dichloro-2-propyl) phosphate (TDCIPP) increased the OR of wheeze, (OR: 1.22, CI: 1.00-1.48). Significant p values for trends were found between tris (2-butoxyethyl) phosphate (TBOEP) and eczema and di-iso-nonyl phthalate (DiNP) and eczema among children without any FLG mutations, respectively.

CONCLUSIONS

Despite our limited sample size and cross-sectional study design, the effects of indoor environmental factors on childhood eczema and wheeze were clearer in children without loss-of-function mutations in FLG than in children with mutations. Children with FLG mutations might already be cared for differently in terms of medication or parental lifestyle. Further studies in larger populations are warranted so that severity of symptoms and combinations of FLG mutations can be investigated.

Phthalates and organophosphates in settled dust and HVAC filter dust of U.S. low-income homes: Association with season, building characteristics, and childhood asthma

Phthalates and organophosphates are ubiquitous indoor semi-volatile organic contaminants (SVOCs) that have been widely used as plasticizers and flame retardants in consumer products. Although many studies have assessed their levels in house dust, only a few used dust samples captured by filters of building heating, ventilation, and air conditioning (HVAC) systems. HVAC filters collect particles from large volumes of air over a long period of time (potentially known) and thus provide a spatially and temporally integrated concentration. This study measured concentrations of phthalates and organophosphates in HVAC filter dust and settled floor dust collected from low-income homes in Texas, United States, in both the summer and winter seasons. The most frequently detected compounds were benzyl butyl phthalate (BBzP), di-(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DnOP), tris (1-chloro-2-propyl) phosphate (TCIPP), triphenyl phosphate (TPHP), and tris (1,3-dichloroisopropyl) phosphate (TDCIPP). The median level of TCIPP in settled dust was 3- to 180-times higher than levels reported in other studies of residential homes. Significantly higher concentrations were observed in HVAC filter dust as compared to settled dust for most of the frequently detected compounds in both seasons, except for several phthalates in the winter. SVOC concentrations in settled dust in winter were generally higher than in summer, while different seasonality patterns were found for HVAC filter dust. Settled dust samples from homes with vinyl flooring contained significantly higher levels of BBzP and DEHP as compared to homes with other types of floor material. The concentration of DEHP and TDCIPP in settled dust also significantly associated with the presence of carpet in homes. Cleaning activities to remove dust from furniture actually increased the levels of certain compounds in HVAC filter dust, while frequent vacuuming of carpet helped to decrease the concentrations of some compounds in settled dust. Additionally, the size and age of a given house also correlated with the levels of some pollutants in dust. A statistically significant association between DEHP concentration in HVAC filter dust in summer and the severity of asthma in children was observed. These results suggest that HVAC filter dust represents a useful sampling medium to monitor indoor SVOC concentrations with high sensitivity; in contrast, when using settled dust, in addition to consideration of seasonal influences, it is critical to know the sampling location because the type and level of SVOCs may be related to local materials used there.

Common SVOCs in house dust from urban dwellings with schoolchildren in six typical cities of China and associated non-dietary exposure and health risk assessment

This paper presents concentrations of common SVOCs in house dusts from urban dwellings with schoolchildren in six typical Chinese cities in winter and summer. Among the detected SVOCs, DBP and DEHP have a higher detection rate. The levels of these two substances contribute an average proportion of over 90% of the total SVOCs' levels, and show a significant correlation in most cities. Based on measured concentrations, schoolchildren's non-dietary exposures to DBP and DEHP at homes are estimated. Due to a longer time spent in child's bedrooms, children's non-dietary exposures to phthalates in child's bedrooms are greatly higher than that in living rooms. As for DBP non-dietary exposure, the most significant pathway is dermal absorption from air, accounting for >70%, whereas, the most predominant pathway for DEHP non-dietary exposure is dust ingestion, contributing from 61.5% to 91.9%. Based on estimated exposure doses, child-specific reproductive and cancer risk are assessed by comparing the exposure doses with DBP and DEHP benchmarks specified in California's Proposition 65. Owing to the high DBP exposure, nearly all of target schoolchildren appear to have a severe reproductive risk, although only non-dietary exposures at home are considered in this study. The average risk quotient of DBP exposure for child-specific MADL in all cities is 31.27 in winter and 10.35 in summer. Also, some schoolchildren are confronted with potential carcinogenic risk, because DEHP exposure exceeds child-specific NSRLs. The maximum DEHP exposure exceeds the cancer benchmark by over 6 times. These results also indicate that controlling indoor phthalates pollution at home is urgent to ensure the healthy development of children in China.

Novel and Traditional Organophosphate Esters in House Dust from South China: Association with Hand Wipes and Exposure Estimation

The present study investigated the occurrence of 20 organophosphate esters (OPEs) in house dust from 51 South China homes and the risks of human exposure to OPEs via two pathways: dust ingestion and hand-to-mouth contact. In addition to several traditional OPEs, five out of six novel OPEs, including bisphenol A bis(deiphenyl phosphate) (BPA-BDPP), t-butylphenyl diphenyl phosphate (BPDPP), cresyl diphenyl phosphate (CDP), isodecyl diphenyl phosphate (IDDPP), and resorcinol-bis(diphenyl)phosphate (RDP), were frequently detected in house dust (median concentration: 59.7-531 ng/g). Eight of the 20 target OPEs were frequently detected in hand wipes collected from adults and children ( n = 51 and 31, respectively), which in combination (referred to as Σ₈OPEs) had a median mass of 76.9 and 58.9 ng, respectively. Increasing dust concentrations of Σ₈OPEs or three individual substances among these eight OPEs, including tris(1-chloro-2-propyl) phosphate (TCIPP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), and triphenyl phosphate (TPHP), were strongly associated with their levels in children's hand wipes ( p < 0.05 in all cases). By contrast, in adults' hand wipes only TPHP exhibited a marginally significant association with dust concentrations ( p = 0.04). Levels of Σ₈OPEs in hand wipes from children, but not adults, were inversely influenced by hand washing frequency ( p = 0.002), while indoor temperature was inversely associated with hand wipe levels of Σ₈OPEs from both children and adults ( p = 0.01 and 0.002, respectively). Exposure estimation suggests that hand-to-mouth contact represents another important pathway in addition to dust ingestion and that children are subjected to higher OPE exposure than adults.

Associations between allergic symptoms and phosphate flame retardants in dust and their urinary metabolites among school children

BACKGROUND

Phosphate flame retardants (PFRs) are ubiquitously detected in indoor environments. Despite increasing health concerns pertaining to PFR exposure, few epidemiological studies have examined PFR exposure and its effect on children's allergies.

OBJECTIVES

To investigate the association between PFRs in house dust, their metabolites in urine, and symptoms of wheeze and allergies among school-aged children.

METHODS

A total of 128 elementary school-aged children were enrolled. House dust samples were collected from upper-surface objects. Urine samples were collected from the first morning void. Levels of 11 PFRs in dust and 14 PFR metabolites in urine were measured. Parent-reported symptoms of wheeze, rhinoconjunctivitis, and eczema were evaluated using the International Study of Asthma and Allergies in Childhood questionnaire. The odds ratios (ORs) of the Ln transformed PFR concentrations and categorical values were calculated using a logistic regression model adjusted for sex, grade, dampness index, annual house income, and creatinine level (for PFR metabolites only).

RESULTS

The prevalence rates of wheeze, rhinoconjunctivitis, and eczema were 22.7%, 36.7%, and 28.1%, respectively. A significant association between tris(1,3-dichloroisopropyl) phosphate (TDCIPP) in dust and eczema was observed: OR (95% confidence interval), 1.44 (1.13-1.82) (>limit of detection (LOD) vs <LOD). The ORs for rhinoconjunctivitis (OR = 5.01 [1.53-16.5]) and for at least one symptom of allergy (OR = 3.87 [1.22-12.3]) in the 4th quartile of Σtris(2-chloro-isopropyl) phosphate (TCIPP) metabolites was significantly higher than those in the 1st quartile, with significant p-values for trend (P_trend) (0.013 and 0.024, respectively). A high OR of 2.86 (1.04-7.85) (>LOD vs <LOD) was found for hydroxy tris(2-butoxyethyl) phosphate (TBOEP)-OH and eczema. OR of the 3rd tertile of bis (1,3-dichloro-2-propyl) phosphate (BDCIPP) was higher than the 1st tertile as a reference for at least one symptom (OR = 3.91 [1.25-12.3]), with a significant P_trend = 0.020.

CONCLUSIONS

We found that TDCIPP in house dust, and metabolites of TDCIPP, TBOEP and TCIPP were associated with children's allergic symptoms. Despite some limitations of this study, these results indicate that children's exposure to PFR may impact their allergic symptoms.

Concentration and factors affecting the distribution of phthalates in the air and dust: A global scenario

Phthalates are ubiquitously present environmental contaminants. Air and dust are the most important mediums of exposure to phthalates. The present study reviews the presence of phthalates in the air and dust reported from different countries in the last ten years (2007-2017). The phthalate concentrations revealed wide heterogeneity with a mean and median value 6 ± 19 μg/m³ and 0.5 μg/m³ respectively in the air and 1.5 × 10³ ± 2.2 × 10³ μg/g and 7.8x10²μg/g respectively in the dust. The highest phthalates levels in the air were reported from India (1.1 × 10² μg/m³) and in dust from Bulgaria (1.2 × 10⁴ μg/g). Overall higher levels were reported from developing countries as compared to developed countries. Di (2-ethylhexyl) phthalate (DEHP) and Di-n-butyl phthalate (DBP) were found to be predominant in both air and dust. Temperature, humidity, air exchange rate, building material and indoor maintenance were reported as the important factors influencing the levels of phthalates in the air and dust. In addition to policy level interventions, reducing the use of phthalate containing materials and controlling the factors which enhance the emission from existing sources can help in reducing human exposure to phthalates.

Recent biomonitoring reports on phosphate ester flame retardants: a short review

Organophosphate triesters (PEFRs) are used increasingly as flame retardants and plasticizers in a variety of applications, such as building materials, textiles, and electric and electronic equipment. They have been proposed as alternatives to brominated flame retardants. This updated review shows that biomonitoring has gained incrementally greater importance in evaluating human exposure to PEFRs, and it holds the advantage of taking into account the multiple potential sources and various intake pathways of PEFRs. Simultaneous and extensive internal exposure to a broad range of PEFRs have been reported worldwide. Their metabolites, mainly dialkyl or diaryl diesters, have been used as biomarkers of exposure and have been ubiquitously detected in the urine of adults and children in the general population. Concentrations and profiles of PEFR urinary metabolites are seen to be variable and are highly dependent on individual and environmental factors, including age, country regulation of flame retardants, and types and quantities of emissions in microenvironments, as well as analytical procedures. Additional large biomonitoring studies, using a broad range of urinary diesters and hydroxylated metabolites, would be useful to improve the validity of the biomarkers and to refine assessments of human exposure to PEFRs.

[New Scientific Evidence-based Public Health Guidelines and Practical Manual for Prevention of Sick House Syndrome]

Recently, we have published a book containing evidence-based public health guidelines and a practical manual for the prevention of sick house syndrome. The manual is available through the homepage of the Ministry of Health, Labour and Welfare (http://www.mhlw.go.jp/file/06-Seisakujouhou-11130500-Shokuhinanzenbu/0000155147.pdf). It is an almost completely revised version of the 2009 version. The coauthors are 13 specialists in environmental epidemiology, exposure sciences, architecture, and risk communication. Since the 1970s, health problems caused by indoor chemicals, biological pollution, poor temperature control, humidity, and others in office buildings have been recognized as sick building syndrome (SBS) in Western countries, but in Japan it was not until the 1990s that people living in new or renovated homes started to describe a variety of nonspecific subjective symptoms such as eye, nose, and throat irritation, headache, and general fatigue. These symptoms resembled SBS and were designated "sick house syndrome (SHS)." To determine the strategy for prevention of SHS, we conducted a nationwide epidemiological study in six cities from 2003-2013 by randomly sampling 5,709 newly built houses. As a result 1,479 residents in 425 households agreed to environmental monitoring for indoor aldehydes and volatile organic compounds (VOCs). After adjustment for possible risk factors, some VOCs and formaldehyde were dose-dependently shown to be significant risk factors. We also studied the dampness of the houses, fungi, allergies, and others. This book is fully based on the scientific evidence collected through these studies and other newly obtained information, especially from the aspect of architectural engineering. In addition to SHS, we included chapters on recent information about "multi-chemical sensitivity."

Passive air sampling of flame retardants and plasticizers in Canadian homes using PDMS, XAD-coated PDMS and PUF samplers

Passive air samplers (PAS) were evaluated for measuring indoor concentrations of phthalates, novel brominated flame retardants (N-BFRs), polybrominated diphenyl ethers (PBDEs), and organophosphate esters (OPEs). Sampling rates were obtained from a 50-day calibration study for two newly introduced PAS, polydimethylsiloxane (PDMS) or silicone rubber PAS (one with and one without a coating of styrene divinyl benzene co-polymer, XAD) and the commonly used polyurethane foam (PUF) PAS. Average sampling rates normalized to PAS surface area were 1.5 ± 1.1 m³ day^-1 dm^-2 for both unsheltered PDMS and XAD-PDMS, and 0.90 m³ ± 0.6 day^-1dm^-2 for partially sheltered PUF. These values were derived based on the compound-specific sampling rates measured here and in the literature for the PAS tested, to reasonably account for site-specific variability of sampling rates. PDMS and PUF were co-deployed for three weeks in 51 homes located in Ottawa and Toronto, Canada. Duplicate PUF and PDMS samplers gave concentrations within 10% of each other. PDMS and PUF-derived air concentrations were not statistically different for gas-phase compounds. PUF had a higher detection of particle-phase compounds such as some OPEs. Phthalate and OPE air concentrations were ∼100 times higher than those of N-BFRs and PBDEs. Concentrations were not systematically related to PM₁₀, temperature or relative humidity. We conclude that both PAS provide replicable estimates of indoor concentrations of these targeted semi-volatile organic compounds (SVOCs) over a three-week deployment period. However, PUF is advantageous for collecting a wider range of compounds including those in the particle phase.

Occurrence and partitioning behavior of organophosphate esters in surface water and sediment of a shallow Chinese freshwater lake (Taihu Lake): Implication for eco-toxicity risk

Organophosphate esters (OPEs) are ubiquitous in the aquatic environment, which have been considered or suspected as carcinogens and neurotoxicants. In this study, the occurrence, spatial distribution, potential sources, partitioning character and potential risks of OPEs in the surface water and sediment collected from Taihu Lake were investigated. The concentrations of ∑12 OPEs varied from 1.0 × 10² to 1.7 × 10³ ng/L for the surface water and from 8.1 to 4.2 × 10² ng/g dw for the sediment. Trimethyl phosphate (TEP) was the predominant congener in the surface water, while Tris(2-ethylhexyl) phosphate (TEHP) in the sediment. Positive correlations between OPEs indicated that they may have the same sources and/or similar environmental behavior. The pseudo-partitioning values of OPEs ranged from 0.59 to 6.5 × 10⁴ L/kg. TEHP has the highest pseudo-partitioning coefficient, which indicated that TEHP inclined to be enriched in the sediment in Taihu Lake. Risk assessment (RQ) showed that individual OPEs in the surface water and sediment posed no/low risk to aquatic organisms, except 2-Ethylhexyl diphenyl phosphate (EHDPP) (moderate risk) in water.

Phthalates contamination in China: Status, trends and human exposure-with an emphasis on oral intake

Despite the extensive production and use of phthalates in Asian countries, especially China, limited information is available about the current situation of human exposure in this region, and thus identification of further research needs is warranted. This review summarized the current trends of phthalates related to industrial production and human exposure by conducting a comprehensive assessment of phthalates contaminations in air, indoor dust, personal care products (PCPs), foodstuff and internal exposure in China, with comparisons with other countries. The concentrations of phthalates in indoor dust and PCPs in China were moderate, while concentrations in foods and air were among the highest worldwide. Dietary intake of phthalates varied with location, with hotspots in the southern and eastern coastal regions of China which correlated with the extensive industrial production recorded in these regions. This review firstly revealed the significantly differentiated food-type contribution profiles for phthalates in China and in other countries, which were affected by dietary habits and food contamination. The internal exposure for the Chinese population was found to be moderate, however there is a paucity of data available. Knowledge gaps identified concerning phthalates in China include trends in phthalates exposure, sources (e.g. PCPs, pharmaceuticals and medical treatment), and internal exposure derived from biomonitoring, warranting phthalates a research priority.

Currently used organophosphate flame retardants determined in the settled dust of masjids and hotels of Saudi Arabia, a new insight into human health implications of dust exposure

Indoor settled dust particles are considered as an important source of human exposure to chemicals such as organophosphate flame retardants (PFRs). In recent decades the Kingdom of Saudi Arabia (KSA) has experienced tremendous growth in population, as a result the number of masjids has also increased significantly to provide sufficient space for the public to offer prayers. The hospitality industry in KSA is also expanding to cater for the ever-increasing number of pilgrims visiting the two holy cities of the kingdom. However, limited data are available on the indoor pollution of masjids and hotels. In this study, PFRs were analyzed in the settled dust collected from various hotels and masjids of Jeddah, KSA. Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and tris(1-chloro-2-propyl) phosphate (TCPP) were the major PFRs in masjid (median = 2490 and 2055 ngg-1) and hotel (median = 2360 and 3315 ngg-1) dust, respectively. A public health risk assessment was carried out by determining the incremental lifetime cancer risk (ILCR), and daily exposure via dust ingestion, inhalation, and dermal contact of PFRs. The calculated daily exposure via dust ingestion was well below the reference dose (RfD) values, and also the calculated hazardous quotient (HQ) and carcinogenic risk were well below the risk mark. However, the ILCR for PFRs was below the reference values of USEPA, which suggested that long-term exposure to these chemicals has a limited cause for concern. The study showed that the general public is exposed to PFRs in the studied microenvironments and the major exposure routes are dermal contact and ingestion.

[Determination of S-421 in Commercial Fish and Shellfish]

S-421 is a synergist of pyrethroid and organophosphorus pesticides, which are used as termiticides or household insecticides. S-421 is stable and ubiquitous in the environment. Here we describe the concentrations of S-421 in domestic and imported commercial fish collected from 2009 to 2016. Samples were extracted with acetone/hexane and S-421 was purified on a silica gel column. Quantitative analysis was performed by GC-ECD. S-421 was detected in 78 of 116 samples of domestic fish and shellfish at levels of <0.2 to 2.6 ng/g (mean: 0.4 ng/g), and in 69 of 102 imported samples at a level of <0.2 to 1.5 ng/g (mean: 0.4 ng/g). The concentrations of S-421 in fish were lower than those of p,p'-DDE and similar to those of β-HCH.