Phthalate esters in indoor dust from several regions, China and their implications for human exposure

Children's exposure to halogenated flame retardants and organophosphate esters through dermal absorption and hand-to-mouth ingestion in Swedish preschools

Children are exposed to endocrine disrupting chemicals (EDCs) through inhalation and ingestion, as well as through dermal contact in their everyday indoor environments. The dermal loadings of EDCs may contribute significantly to children's total EDC exposure due to dermal absorption as well as hand-to-mouth behaviors. The aim of this study was to measure potential EDCs, specifically halogenated flame retardants (HFRs) and organophosphate esters (OPEs), on children's hands during preschool attendance and to assess possible determinants of exposure in preschool indoor environments in Sweden. For this, 115 handwipe samples were collected in winter and spring from 60 participating children (arithmetic mean age 4.5 years, standard deviation 1.0) and analyzed for 50 compounds. Out of these, 31 compounds were identified in the majority of samples. Levels were generally several orders of magnitude higher for OPEs than HFRs, and 2-ethylhexyl diphenyl phosphate (EHDPP) and tris(2-butoxyethyl) phosphate (TBOEP) were detected in the highest median masses, 61 and 56 ng/wipe, respectively. Of the HFRs, bis(2-ethyl-1-hexyl)-2,3,4,5-tetrabromobenzoate (BEH-TEBP) and 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) were detected in the highest median masses, 2.8 and 1.8 ng/wipe, respectively. HFR and/or OPE levels were found to be affected by the number of plastic toys, and electrical and electronic devices, season, municipality, as well as building and/or renovation before/after 2004. Yet, the calculated health risks for single compounds were below available reference dose values for exposure through dermal uptake as well as for ingestion using mean hand-to-mouth contact rate. However, assuming a high hand-to-mouth contact rate, at the 95th percentile, the calculated hazard quotient was above 1 for the maximum handwipe mass of TBOEP found in this study, suggesting a risk of negative health effects. Furthermore, considering additive effects from similar compounds, the results of this study indicate potential concern if additional exposure from other routes is as high.

Phthalate alternatives and their monoesters in indoor dust from several regions, China and implications for human exposure

Household products, in response to regulations, increasingly incorporate phthalate (PAE) alternatives instead of traditional PAEs. However, limited information exists regarding the fate and exposure risk of these PAE alternatives and their monoesters in indoor environments. The contamination levels of PAE alternatives and their monoesters in indoor dust might vary across regions due to climate, population density, industrial activities, and interior decoration practices. By analyzing indoor dust samples from six geographical regions across China, this study aims to shed light on concentrations, profiles, and human exposure to 12 PAE alternatives and 9 their monoesters. Bis(2-ethylhexyl) benzene-1,4-dicarboxylate (DEHTP), tributyl 2-acetyloxypropane-1,2,3-tricarboxylate (ATBC), and tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate (TOTM) were the main PAE alternatives in dust across all regions. The total concentrations of 12 PAE alternatives ranged from 0.125 to 4160 μg/g in indoor dust. High molecular weight PAE alternatives had significantly correlated concentrations (p < 0.05) based on Spearman analysis, suggesting their co-use in heat-resistant plastic products. A collective of nine monoesters were identified in most samples, with total concentrations ranging from 0.048 to 29.6 μg/g. The median concentrations of PAE alternatives were highest in North China (66.8 μg/g), while those of monoesters were highest in Southwest China (6.93 μg/g). A significant correlation (p < 0.05) between the concentrations of DEHTP and its monoester suggested that degradation could be a potential source of monoesters. Although hazard quotients (HQs) have been calculated to suggest that the current exposure is unlikely to pose a significant health risk, the lack of toxicity threshold data and the existence of additional exposure pathways necessitate a further confirmation.

Liquid crystal monomers (LCMs) in indoor residential dust from Beijing, China: occurrence and human exposure

Liquid crystal monomers (LCMs) are widely used in electronic devices and emerging as an environmental pollutant, while their occurrence in indoor environments is still less studied. In this study, 32 out of 37 target LCMs were detected in indoor residential dust samples (n = 112) from Beijing, China. Concentrations of Σ32LCMs ranged from 17.8 to 197 ng/g, with a median value of 54.7 ng/g. Fluorinated biphenyls and analogs (FBAs) and cyanobiphenyls and analogs (CBAs), with median concentrations of 22.8 and 15.9 ng/g, respectively, were the main kinds of LCMs. Although 32 LCMs can be detected, four monomers with the highest contamination levels contributed to almost 70% of the total LCMs. Spearman correlation analysis found significant correlations among some monomers, which indicated that they might share similar sources in the residential environment. Estimated daily intakes (EDIs) of LCMs via indoor dust for Beijing residents were calculated, and the results showed that dust ingestion and dermal contact were both main intake pathways to LCMs, and younger people may face higher exposure to LCMs. A comparison to the results of China's total diet study showed that EDIs of LCMs via food consumption might be higher than that via dust intake, while health risks caused by exposure of LCMs for the general population, both through food and dust, were insignificant at present.

Multi-source exposure and health risks of phthalates among university students in Northeastern China

The endocrine disruptor phthalates (PAEs) are widely used as important chemical additives in a variety of areas around the globe. PAEs are toxic to reproduction and development and may adversely affect the health of adolescents. Risk assessments of exposure to PAEs from different sources are more reflective of actual exposure than single-source assessments. We used personal exposure parameters to estimate the dose of PAEs to 107 university students from six media (including dormitory dust, dormitory air, clothing, food, disposable food containers, and personal care products (PCPs)) and three exposure routes (including ingestion, inhalation, and dermal absorption). Individual factors and lifestyles may affect PAE exposure to varying degrees. Based on a positive matrix factorization (PMF) model, the results indicated that the main sources of PAEs in dust were indoor building materials and plastics, while PCPs and adhesives were the major sources of airborne PAEs. The relative contribution of each source to PAE exposure showed that food and air were the primary sources of dimethyl phthalate (DMP) and dibutyl phthalate (DBP). Air source contributed the most to diethyl phthalate (DEP) exposure, followed by PCPs. Food was the most significant source of diisobutyl phthalate (DiBP), benzyl butyl phthalate (BBP), and bis(2-ethylhexyl) phthalate (DEHP) exposure. Additionally, the exposure of DEHP to dust was not negligible. The ingestion pathway was the most dominant among the three exposure pathways, followed by dermal absorption. The non-carcinogenic risk of PAEs from the six sources was within acceptable limits. DEHP exhibits a low carcinogenic risk. We suggest university students maintain good hygienic and living habits to minimize exposure to PAEs.

A novel method for assessing indoor di 2-ethylhexyl phthalate (DEHP) contamination and exposure based on dust-phase concentration

Phthalates (PAEs) are a group of typical semivolatile organic compounds that are widely present in indoor environments with multiple phases. Indoor air, airborne particle and settled dust are considered to be typical indicators of PAE contamination as well as media of human exposure, and the interactions between them are complex. Among various phthalate compounds, di 2-ethylhexyl phthalate (DEHP) was identified as the predominant individual phthalate in settled dust. The existing DEHP contamination assessment requires multiphase sampling or solving the dynamic mass transfer models with multiple partial differential equations, which are both complicated and time-consuming. This study investigated the influence of the indoor source loading rate, surface type, particle size and cleaning frequency on the partitioning between the settled dust-phase, airborne particle-phase and gas-phase. The concentration correlations of DEHP between multiphases were consequently derived, which balance accuracy and complexity well. By comparison with field sampling data in the literatures, the rationality and accuracy of the concentration correlations were validated. Based on the concentration correlations, a new method of directly using dust-phase concentration to estimate the non-dietary exposure to DEHP was proposed. The results indicated that ingestion of settled dust contributes the most to non-dietary exposure. Special attention should be given to infants and toddlers, who suffer the highest daily exposure to DEHP among all age groups. This study provides a new and efficient solution for estimating indoor DEHP pollution loads conveniently and rapidly, offering valuable insights for future research in this field.

Evaluating the risk of phthalate and non-phthalate plasticizers in dust samples from 100 Japanese houses

Phthalates are widely used as plasticizer and associated with various health issues. Recently, non-phthalate plasticizers are replacing phthalates; however, the exposure to these substances and the risk in Japan is unclear. In this study, we assessed the concentrations of phthalates, non-phthalate plasticizers, and phthalate degradation products in house dust and determined their respective exposure risks via oral and dermal routes. Twelve phthalates, seven non-phthalate plasticizers, and two degradation products were determined in the house dust obtained from 100 Japanese homes. The median concentration of di(2-ethylhexyl) phthalate (DEHP), accounting for 85 % of the total concentration of phthalates and non-phthalate plasticizers detected in this study, was 2.1 × 103 μg/g of dust. Apart from DEHP, diisononyl phthalate (DINP) and di(2-ethylhexyl) terephthalate (DEHT) were the most abundant in the house dust, accounting for 6.2 % (median: 1.7 × 102 μg/g of dust) and 6.1 % (median: 1.7 × 102 μg/g of dust) of the total concentrations, respectively. DEHP and DEHT concentrations in house dust were higher in apartment and small houses (floor area: ≤30 m2 or 31-60 m2 for DEHP and 31-60 m2 for DEHT) than in detached and large houses (floor area: ≥121 m2). Conversely, di-n-butyl phthalate (DnBP) concentrations were significantly higher in detached and large houses (floor area: ≥121 m2) than in apartment and small houses (floor area: ≤30 m2). The total hazard quotient (HQ), using the maximum concentration in house dust, revealed that oral and dermal exposure to house dust was 1.3 × 10-6-0.11 for adults (all substances) and 1.6 × 10-5-2.2 × 10-2 for preschool children (except for DnBP and DEHP), suggesting no risk. The HQs for DnBP and DEHP exposure via house dust for preschool children using the maximum values were 0.46 and 1.2, and 6.0 × 10-3 and 0.18 using the median values, indicating that risk of DEHP exposure should be exhaustively determined by considering other exposure routes that were not evaluated in this study, such as diet.

Accumulation, sources, and health risks of phthalic acid esters (PAEs) in road dust from heavily industrialized, urban and rural areas in southern Iran

In this research, a total of 51 road dust samples were collected from three districts (Asaluyeh, Bushehr, and Goshoui) in the south of Iran from April to June 2022 and analyzed for the concentration of 7 phthalic acid esters (PAEs) compounds. Asaluyeh was considered as an industrial area (near gas and petrochemical industries), Bushehr as an urban area, and Goshoui as a rural area (far from pollution sources). The PAEs concentration of the street dust samples was determined using a mass detection gas chromatography (GC/MS). The mean ± SD levels of ƩPAEs in samples from industrial, urban, and rural sources were 56.9 ± 11.5, 18.3 ± 9.64, and 5.68 ± 1.85 μg/g, respectively. The mean concentration levels of ƩPAEs was significantly (P < 0.05) higher in samples from the industrial area than urban and rural areas. The mean levels of di(2-Ethylhexyl) phthalate (DEHP) in industrial, urban, and rural areas were 20.3 ± 8.76, 4.59 ± 1.71, and 2.35 ± 0.98 μg/g, respectively. The results of the PCA analysis indicate that the likely major sources of PAEs in the road dust in the studied areas are the application of various plasticizers in industry, solvents, chemical fertilizers, waste disposal, wastewater (e.g., agricultural, domestic, and industrial), and the use of plastic films and plastic-based irrigation pipes in greenhouses. As well as, it was found that the non-cancer risk of exposure to dust-bound PAEs was higher for children than for adults. These values were <1 for both age groups (children and adults) and the exposure of inhabitants to PAEs in road dust did not pose a notable non-cancer risk. The cancer risk from exposure to DEHP in road dust was below the standard range of 10-6 in all three areas. Further studies that consider different routes of exposure to these contaminants are needed for an accurate risk assessment. Moreover, since higher PAEs level was found in industrial area, decision-makers should adopt strict strategies to control the discharging of pollution from industries to the environment and human societies.

Co-occurrence of phthalate and non-phthalate plasticizers in dust and hand wipes: A comparison of levels across various sources

E-waste dismantlers' occupational exposure to plasticizers, particularly non-phthalate (NPAE) plasticizers, is poorly understood. This study monitored 11 phthalates (PAEs) and 16 NPAEs in dust and hand wipe samples from Central China e-waste workplace and ordinary homes. Concentrations of plasticizers in dust from e-waste dismantling workshops (median: 217 μg/g) were significantly lower than that from ordinary homes (462 μg/g; p < 0.01), however, the trend was similar but not significant in hand wipes from these two scenarios (50.2 vs. 72.3 μg/m2; p = 0.139). PAEs were still the dominant plasticizers, which is, on average, 5.46 and 3.58-fold higher than NPAEs. In all samples, di-(2ethylhexyl) phthalate (65.4%) and tri-octyl trimellitate (44.9%) were the most common PAE and NPAE plasticizers. Increasing dust concentrations of di-iso-nonyl ester 1,2-cyclohexane dicarboxylic acid, citrates and sebacates were significantly associated with their levels in worker's hand wipe, by contrast, this trend was not found in general population. Dust ingestion was the main channel, followed by hand-to-mouth contact, all participants' daily plasticizer intakes (median: 154 ng/kg bw/day) are within safety limits. Our work highlights knowledge gaps about co-exposure to PAEs and NPAEs by multiple pathways in occupational e-waste workers, which could provide baseline data in the future.

Levels and health risk assessments of Phthalate acid esters in indoor dust of some microenvironments within Ikeja and Ota, Nigeria

The levels, profiles of Phthalate acid esters (PAEs) and their associated health risk in children and adults using indoor dust samples were assessed from nine (9) microenvironments in Nigeria. Six PAEs congeners were determined using Gas Chromatography-Mass Spectrometry and the human health risk assessments of PAEs exposure to children and adults were computed using the United States Environmental Protection Agency (USEPA) exposure model. The mean concentrations of the total PAEs (Σ₆PAEs) in indoor dust across the study locations ranged from 1.61 ± 0.12 to 53.3 ± 5.27 μg/g with 72.0% of di-n-octyl phthalate (DnOP) as the most predominant contributor of PAEs in sample locations B, C, D, E, F and G. PAEs estimated daily intake results exceeded the USEPA value of 20 and 50 kg/bw/day for children and adults respectively in some locations. Non-carcinogenic risk exposure indicated no risk (HI < 1), while the carcinogenic risk was within the recommended threshold of 1.00 × 10^-4 to 1.00 × 10^-6 for benzyl butyl phthalate and bis-2-ethylhexyl phthalate. From our findings, lower levels of PAEs were observed in locations with good ventilation system. Also, the human health risk evaluation indicated indoor dust ingestion as the dominant exposure route of PAEs for both children and adults, while the children were at a higher risk of PAEs exposure. To protect children susceptible to these endocrine-disrupting pollutants, soft vinyl children's toys and teething rings should be avoided. Appropriate policies and procedures on the reduction of PAEs exposure to humans should be enacted by all stakeholders, including government regulatory agencies, industries, school administrators and the entire community.

Endocrine disrupting chemicals in indoor dust: A review of temporal and spatial trends, and human exposure

Several chemicals with widespread consumer uses have been identified as endocrine-disrupting chemicals (EDCs), with a potential risk to humans. The occurrence in indoor dust and resulting human exposure have been reviewed for six groups of known and suspected EDCs, including phthalates and non-phthalate plasticizers, flame retardants, bisphenols, per- and polyfluoroalkyl substances (PFAS), biocides and personal care product additives (PCPs). Some banned or restricted EDCs, such as polybrominated diphenyl ethers (PBDEs), di-(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), are still widely detected in indoor dust in most countries, even as the predominating compounds of their group, but generally with decreasing trends. Meanwhile, alternatives that are also potential EDCs, such as bisphenol S (BPS), bisphenol F (BPF), decabromodiphenyl ethane (DBDPE) and organophosphate flame retardants (OPFRs), and PFAS precursors, such as fluorotelomer alcohols, have been detected in indoor dust with increasing frequencies and concentrations. Associations between some known and suspected EDCs, such as phthalate and non-phthalate plasticizers, FRs and BPs, in indoor dust and paired human samples indicate indoor dust as an important human exposure pathway. Although the estimated daily intake (EDI) of most of the investigated compounds was mostly below reference values, the co-exposure to a multitude of known or suspected EDCs requires a better understanding of mixture effects.

Exposure to phthalates and DiNCH among preschool children in Sweden: Urinary metabolite concentrations and predictors of exposure

Several plasticizing chemicals induce endocrine disrupting effects in humans, and the indoor environment is suggested to be a source of exposure. As children are particularly vulnerable to the effects from exposure to endocrine disrupting chemicals (EDCs), it is essential to monitor exposure to EDCs such as phthalates and non-phthalate plasticizers in indoor environments intended for use by children. The aim of this study was to assess everyday plasticizer exposure among preschool-aged children in Sweden by measuring urinary plasticizer metabolite concentrations. In addition, it was investigated whether the concentrations would be altered as a result of the children spending part of the day at preschool, in comparison with weekend exposure, when they may spend more time in home environments or engage in various weekend and leisure activities. For this purpose, fourteen metabolites from eight phthalates (di-ethylhexyl phthalate, DEHP; di-n-butyl phthalate, DnBP; di-isobutyl phthalate, DiBP; butyl-benzyl phthalate, BBzP; di-iso-nonyl phthalate, DiNP; di-propylheptyl phthalate, DPHP; di-iso-decyl phthalate, DiDP; and di-ethyl phthalate, DEP) and one non-phthalate plasticizer (di-isononyl cyclohexane 1,2-dicarboxylate, DiNCH) were measured in 206 urine samples collected at four occasions, i.e. twice during the winter and twice during the spring from 54 children (mean 5.1 years, SD 0.94) enrolled at eight preschools in Sweden. A detection frequency (DF) of 99.9% for the 14 metabolites indicates a widespread exposure to plasticizers among children in Sweden. Compared to previous Swedish and international studies performed during approximately the same time period, high urinary concentrations of monobenzyl phthalate (MBzP), a metabolite from the strictly regulated BBzP, were measured in this study (median 17 ng/mL). Overall, high urinary phthalate metabolite concentrations were observed in this study compared to the US CDC-NHANES from the same time period and similar age-group. Compared to European studies, however, similar concentrations were observed for most metabolites and the urinary concentrations from few participating children exceeded the human biomonitoring guidance values (HBM-GV) for children. After days with preschool attendance, lower urinary concentrations of metabolites originating from DEP and phthalates that are strictly regulated within the EU REACH legislation (DEHP, DnBP, and DiBP) and higher concentrations of metabolites originating from DiNP, DPHP, and DiDP, i.e. less or non-regulated phthalates were found compared the urinary concentrations of these metabolites in weekends. This may indicate that factors in the indoor environment itself are important for the extent of the plasticizer exposure. All the analyzed metabolites were measured in lower concentrations in urine collected from children attending preschools built or renovated after the year 2000, while no seasonal differences were observed in this study.

Environmentally relevant concentrations of butyl benzyl phthalate triggered oxidative stress and apoptosis in adult zebrafish (Danio rerio) liver: Combined analysis at physiological and molecular levels

Butyl benzyl phthalate (BBP), a typical phthalate plasticizer, is frequently detected in aquatic environments, but its possible effects on fish liver are unknown. In this study, adult zebrafish were exposed to 5-500 μg/L BBP and cultured for 28 days. The toxicity mechanism of environmentally relevant concentrations of BBP in the liver was explored using integrated biomarker response (IBR), molecular docking, and histopathological analysis, based on the tests of oxidative stress, apoptosis, and tissue damage, respectively. The results revealed that exposure to 500 μg/L BBP caused lipid peroxidation and DNA damage and induced inflammatory responses in the liver and intestinal tissues. The accumulation of reactive oxygen species (ROS) is the primary manifestation of BBP toxicity and is accompanied by changes in the activities of antioxidant and detoxification enzymes. Notably, the pro-apoptotic genes (p53 and caspase-3) were still significantly upregulated in the 50 μg/L and 500 μg/L treatment groups on day 28. Moreover, BBP interfered with apoptosis by forming a stable complex with apoptosis proteins (P53 and Caspase-3). Our findings are helpful for understanding the toxicity mechanisms of BBP, which could further promote the assessment of the potential environmental risks of BBP.

Is e-waste a source of phthalate and novel non-phthalate plasticizers? A comparison study on indoor dust

Nine traditional phthalate plasticizers and 33 novel non-phthalate plasticizers were determined in indoor dust from a typical e-waste recycling area. The median concentrations ranged from <LOQ to 22,700 ng/g for phthalates and from <LOQ to 1250 ng/g for non-phthalates. Bis-(2-ethylhexyl) phthalate (DEHP) and di-isononyl phthalate (DINP) were the two major phthalates in dust, while glycerol monooleate (GMO) and methyl oleate (MO) were the predominant non-phthalates. Different pollutant patterns among different sites implied multiple sources of the plasticizers. Using the ratio of DINP/DEHP as an indicator, we evaluated the impact of e-waste source emission on the sampling sites, resulting in an impact rank of Matou > Dakeng > Baihetang > Shiding > Jieyang, which was consistent with the local e-waste dismantling activities and supported by polybrominated diphenyl ethers (PBDEs) levels. The correlations between chemical levels and the indicators indicated that most phthalates and non-phthalate plasticizers in the dust, might not be primarily influenced by e-waste emission sources. Additionally, the estimated median human exposures of phthalates and non-phthalates via dust ingestion were 30.6 and 1.82 ng/kg/day for adults, and 299 and 17.8 ng/kg/day for toddlers respectively, indicating negligible health risks.

Profiling of phthalates, brominated, and organophosphate flame retardants in COVID-19 lockdown house dust; implication on the human health

In this study, brominated flame retardants (BFRs), phthalates, and organophosphate flame retardants (PFRs) were analyzed in indoor household dust collected during the COVID-19 related strict lockdown (April-July 2020) period. Floor dust samples were collected from 40 households in Jeddah, Saudi Arabia. The levels of most of the analyzed chemicals were visibly high and for certain chemicals multifold high in analyzed samples compared to earlier studies on indoor dust from Jeddah. Bis (2-ethylhexyl) phthalate (DEHP) was the primary chemical in these dust samples, with a median concentration of 769,500 ng/g of dust. Tris (2-butoxy ethyl) phosphate (TBEP) and Decabromodiphenyl ether (BDE 209) contributed the highest among PFRs and BFRs with median levels of 5990 and 940 ng/g of dust, respectively. The estimated daily exposure in the worst case scenario (23,700 ng/kg bw/day) for Saudi children was above the reference dose (20,000 ng/kg bw/day) for DEHP, and the hazardous index (HI) was also >1. The long-term carcinogenic risk was above the 1 × 10^-5, indicating a risk to the health of Saudi young children from getting exposed to DEHP from indoor dust. This study draws attention to the increased indoor pollution during the lockdown period when all of the daily activities by adults and children were performed indoors, which negatively impacted human health, as suggested by the calculated risk. However, the current study has limitations and warrants more monitoring studies from different parts of the world to understand the phenomenon. At the same time, this study also highlights another side of COVID-19 related to our lives.

Ellie A, Dong H, Ahmad UM. Health Effects of Exposure to Indoor Semi-Volatile Organic Compounds in Chinese Building Environment: A Systematic Review

People spend a considerable portion of their lives indoors; thus, the quality of the indoor environment is crucial. Semi-volatile organic compounds (SVOCs) are among the primary indoor pollutants responsible for various health risks. This paper systematically reviews the impact of SVOC exposure on human health in Chinese built environments. Based on a set of criteria, we judged 12 publications as providing sufficient information on both SVOC exposure and health effects to inform the relationship. Out of six studies on polycyclic aromatic hydrocarbons (PAHs), three observed a positive association between PAH exposure and lung cancer. Out of six studies of phthalate exposure, two studies reported a significant positive association between DEP and DiBP and asthma, between DEP and DEHP and dry cough among children, and between DBP and rhinitis among younger adults. The results of this review suggest that there might be a link between phthalate exposure and asthma and allergies, as well as a link between PAH exposure and lung cancer. However, due to the limited number of studies conducted, more evidence is necessary to definitively guide the establishment of standards for SVOC control in China.

Source tracing and health risk assessment of phthalate esters in household tap-water: A case study of the urban area of Quanzhou, Southeast China

The occurrence of phthalate esters (PAEs) in household tap water has been investigated via the presence of their geochemical characteristics in the pretreatment and transfer processes of water plants in the urban and suburban areas of the subtropical medium-sized city of Quanzhou, southeast China. The results for all approximately 300 tap water samples collected from 6 sampling stations at household kitchens from Nov. 30, 2017, to Dec. 6, 2018, showed that dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutylphthaate (DIBP), di-n-butyl phthalate (DBP), and di(2-ethylhexyl) phthalate (DEHP) could be identified and quantified among the 16 PAE congeners with the developed gas chromatographymass spectrometry method. The levels of the sum of 5 PAE congeners (Σ₅PAEs) for all tap water ranged from 780.0 ng/L to 9180 ng/L, while DIBP and DEHP were the most abundant congeners, accounting for 82.2% in the dry season, 89.9% in the normal season, and 89.3% in the wet season. Factors of the transferring process, such as the spatial distance from the sampling station to the water plant, the material of pipelines, and the storage time of tap water in the pipeline, affected the levels of PAE congeners in tap water from the correlation of Σ₅PAEs levels and transferring distance according to hierarchical cluster analysis. The seasonal variations in Σ₅PAEs and each congener had good agreement with the temperature, suggesting that PAEs in tap water mainly come from raw water, which should be further explored in future work. Health risk assessment of PAEs in tap water with the HQ method showed that the occurrence of DEP and DBP has no noncarcinogenic risk for adults and children, while the concentration of DEHP might cause potential noncarcinogenic risk for adults and children, which should be given considerably more attention.

Health risks of phthalates: A review of immunotoxicity

Phthalates (PAEs) are known environmental endocrine disruptors that have been widely detected in several environments, and many studies have reported the immunotoxic effects of these compounds. Here, we reviewed relevant published studies, summarized the occurrence and major metabolic pathways of six typical PAEs (DMP, DEP, DBP, BBP, DEHP, and DOP) in water, soil, and the atmosphere, degradation and metabolic pathways under aerobic and anaerobic conditions, and explored the molecular mechanisms of the toxic effects of eleven PAEs (DEHP, DPP, DPrP, DHP, DEP, DBP, MBP, MBzP, BBP, DiNP, and DMP) on the immune system of different organisms at the gene, protein, and cellular levels. A comprehensive understanding of the mechanisms by which PAEs affect immune system function through regulation of immune gene expression and enzymes, increased ROS, immune signaling pathways, specific and non-specific immunosuppression, and interference with the complement system. By summarizing the effects of these compounds on typical model organisms, this review provides insights into the mechanisms by which PAEs affect the immune system, thus supplementing human immune experiments. Finally, we discuss the future direction of PAEs immunotoxicity research, thus providing a framework for the analysis of other environmental pollutants, as well as a basis for PAEs management and safe use.

Legacy and alternative flame retardants in indoor dust from e-waste industrial parks and adjacent residential houses in South China: Variations, sources, and health implications

Many studies have elucidated health concerns of informal e-waste recycling activities, yet few has evaluated the effectiveness of the regulations as well as the human exposure risks to adjacent residents. Herein, legacy polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDs), and alternative organophosphate esters (OPEs) were investigated in indoor dust collected from three e-waste industrial parks and five adjacent villages located in south China. The levels and composition patterns varied significantly between workshop and home dust. BDE209 showed much higher (p < 0.01) concentrations in workshop dust versus home dust, while relatively comparable levels were found for OPEs and HBCDs. Principal component analysis revealed that OPEs and PBDEs were mainly related to home and workshop dust, respectively. Results strongly indicated that e-waste dismantling activities still contribute to a high burden of BDE209 to surrounding residents, whilst the sources of OPEs may also originated from household products, especially for TCEP. The estimated daily intakes (EDIs) via dust ingestion and dermal absorption for occupational worker and nearby toddlers were below available reference dose (RfD) values even at worst case scenario. This study highlights the significance of deca-BDEs rather than alternative OPEs in e-waste generated in China, which could provide scientific suggestions for policy formulation.

Phthalates in dormitory dust and human urine: A study of exposure characteristics and risk assessments of university students

Phthalate diesters (PAEs) are prevalent and potentially toxic to human health. The university dormitory represents a typical and relatively uniform indoor environment. This study evaluated the concentrations of phthalate monoesters (mPAEs) in urine samples from 101 residents of university status, and the concentrations of PAEs in dust collected from 36 corresponding dormitories. Di-(2-ethylhexyl) phthalate (DEHP, median: 68.0 μg/g) was the major PAE in dust, and mono-ethyl phthalate (47.9 %) was the most abundant mPAE in urine. The levels of both PAEs in dormitory dust and mPAEs in urine were higher in females than in males, indicating higher PAE exposure in females. Differences in lifestyles (dormitory time and plastic product use frequency) may also affect human exposure to PAEs. Moreover, there were significant positive correlations between the estimated daily intakes of PAEs calculated by using concentrations of PAEs in dust (EDI_D) and mPAEs in urine (EDI_U), suggesting that PAEs in dust could be a significant source of human exposure to PAEs. The value of EDI_D/EDI_U for low molecular weight PAEs (3-6 carbon atoms in their backbone) was lower than that of high molecular weight PAEs. The contribution rate of various pathways to PAE exposure illustrated that non-dietary ingestion (87.8 %) was the major pathway of human exposure to PAEs in dust. Approximately 4.95 % of university students' hazard quotients of DEHP were >1, indicating that there may be some health risks associated with DEHP exposure among PAEs. Furthermore, it is recommended that some measures be taken to reduce the production and application of DEHP.

Characterization and quantification of endocrine disruptors in female menstrual blood samples

Selected endocrine disrupting chemicals (EDCs) were measured in adult female menstrual blood for the first time in Ghana, Africa, taking into account the importance of non-invasive means of matrices sampling in vulnerable groups, such as pregnant women, the elderly or chronically ill people. The menstrual blood samples of twenty (20) female adults between the ages of 25-45 years were sampled. The Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method was applied for the extraction and clean up, while gas chromatography-mass spectrometry (GC-MS) was used to measure the selected EDCs in adult female menstrual blood, taking into account the composition of menstrual discharge. Diethyl phthalate (DEP), Dibutyl phthalate (DBP) and Bis (2-ethylhexyl) phthalate (DEHP) were detected in all samples, whereas bisphenol A (BPA) was found in 13 participants. Dimethyl phthalate (DMP) was detected in 7 participants, Di-n-octyl phthalate (DNOP) was detected in 3 participants, Bis (2-ethylhexyl) adipate (DEHA) and pyrimidine were detected in 2 participants, while benzyl butyl phthalate (BBP) was detected in only 1 participant. The maximum concentration of DEP measured was 115.6 µg.L^-1and the minimum was 439 µg.L^-1. DEHP was the next most abundant phthalate with a maximum measured concentration of 982 µg.L^-1 and minimum of 95 µg.L^-1. The presence of parent phthalates (rather than metabolites) in menstrual blood of all participants studied suggests that bioaccumulation of selected phthalate compounds such as DEHP, DEP and DBP may be occurring with appreciable human toxicity though the carcinogenic exposure risks of DEHP via various routes were much lower than 1 × 10^-6 considered to be very low.

Associations between concentrations of typical ultraviolet filter benzophenones in indoor dust and human hair from China: A human exposure study

Benzophenone-3 (BP-3) has been widely used as a typical ultraviolet (UV) filter in various personal care products. While BP-3 and its derivatives (BPs) have been detected in various environmental matrices, very little is known about the concentration profile of BPs in human hair. The associations of BPs in human hair with those in indoor dust samples collected from the same locations remain largely unclear. In this study, a total of 258 indoor dust samples and 66 human hair samples were collected across China and analyzed to determine the presence of BP-3 and its derivatives. The BP-3 concentrations ranged from 0.386 to 1230 ng/g dw in indoor dust and from 0.149 to 696 ng/g dw in human hair. No difference was found between BPs in indoor dust samples from different geographic regions (p > 0.05), whereas relatively higher BP concentrations were observed for dust from urban regions than dust from rural ones (p < 0.05). A positive correlation was found between the BP-3 concentrations of indoor dust and human hair samples (p < 0.05). The estimated daily intake (EDI) of BPs for humans from indoor dust showed a gender difference (females > males; p < 0.05), with the highest EDI value being found in Southwest China (males: 35.5 pg/kg bw/day; females: 40.6 pg/kg bw/day). This study provides the concentration profiles of BPs in human hair and elucidates the associations between the BP concentrations in indoor dust samples and human hair samples collected across China.

Molecular signatures of organic particulates as tracers of emission sources

Chemical signature of airborne particulates and deposition dusts is subject of study since decades. Usually, three complementary composition markers are investigated, namely, (i) specific organic compounds; (ii) concentration ratios between congeners, and (iii) percent distributions of homologs. Due to its intrinsic limits (e.g., variability depending on decomposition and gas/particle equilibrium), the identification of pollution sources based on molecular signatures results overall restricted to qualitative purposes. Nevertheless, chemical fingerprints allow drawing preliminary information, suitable for successfully approaching multivariate analysis and valuing the relative importance of sources. Here, the state-of-the-art is presented about the molecular fingerprints of non-polar aliphatic, polyaromatic (PAHs, nitro-PAHs), and polar (fatty acids, organic halides, polysaccharides) compounds in emissions. Special concern was addressed to alkenes and alkanes with carbon numbers ranging from 12 to 23 and ≥ 24, which displayed distinct relative abundances in petrol-derived spills and exhausts, emissions from microorganisms, high vegetation, and sediments. Long-chain alkanes associated with tobacco smoke were characterized by a peculiar iso/anteiso/normal homolog fingerprint and by n-hentriacontane percentages higher than elsewhere. Several concentration ratios of PAHs were identified as diagnostic of the type of emission, and the sources of uncertainty were elucidated. Despite extensive investigations conducted so far, the origin of uncommon molecular fingerprints, e.g., alkane/alkene relationships in deposition dusts and airborne particles, remains quite unclear. Polar organics resulted scarcely investigated for pollution apportioning purposes, though they looked as indicative of the nature of sources. Finally, the role of humans and living organisms as actual emitters of chemicals seems to need concern in the future.

Occurrence, exposure and risk assessment of semi-volatile organic compounds in Chinese homes

Indoor semi-volatile organic compounds (SVOCs) can have a significant impact on human health. Previous studies involved the detection of limited classes of indoor SVOCs in different regions of China. However, overall indoor pollution profiles and the associated health risks via multiple exposure pathways remain unclear. High-throughput screening of SVOCs would help clarify the overall indoor pollution status and identify high-risk pollutants. We collected indoor air and dust samples from 35 Chinese homes and investigated the occurrence of a wide range of SVOCs. Ninety-seven SVOCs including phthalate esters (PAEs), polycyclic aromatic hydrocarbons (PAHs), organophosphate esters, alcohols, fatty acids, phenols, etc., were detected in the air (total concentrations: 0.13-48 μg/m³; median: 3.4 μg/m³) and dust (total concentrations: 120-1500 μg/g; median: 490 μg/g) samples. PAEs were the most abundant, accounting for 55.3 ± 28.6% and 43.4 ± 16.9% of the total SVOC concentrations in the air and dust samples respectively. Human exposure and health risks of 34 SVOCs with detection frequencies >10% were assessed based on inhalation, ingestion and dermal absorption of SVOCs from air and dust by infants and adults. In the case of indoor SVOCs with log K_oa < 9, inhalation and dermal contact with air was >90% for adults and >69% for infants. The following five SVOCs in air samples posed significant non-carcinogenic risks and are listed based on their decreasing risk level: dibutyl phthalate > phenanthrene > stearic acid > methyl palmitate > lauryl alcohol. Four PAHs with 2-4 rings posed potential carcinogenic risks, with phenanthrene exceeding the acceptable risk level of 10^-4. The high risks posed by SVOCs were due to inhalation exposure. Therefore, keeping the air concentrations of SVOCs, especially that of PAEs and PAHs under check would greatly benefit human health in indoor environments.

Distribution, source apportionment and health risk assessment of phthalate esters in outdoor dust samples on Tibetan Plateau, China

The urbanization of Tibetan Plateau (TP) probably results in a significant contamination of organic pollutants in the area, such as phthalate esters (PAEs). However, there is a lack of monitoring and evaluation of their occurrence and risks in the outdoor dust on TP. This study for the first time investigated the concentrations, distributions and health risk of PAEs in outdoor dust samples on TP, China. A total of 132 outdoor dust samples were collected from five different functional areas, and results showed the ubiquitous detection of all PAEs in the samples. The Σ₆PAEs concentrations ranged from 0.08 to 31.49 μg·g^-1 with a mean of 3.57 μg·g^-1. High concentrations of Σ₆PAEs in the outdoor dust were found in commercial districts, which were attributed to the heavy use of PAEs in the public commerce such as consumer products, commodities, and building materials. Di-n-butyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP) were the dominant components accounting for 30.65% and 53.19% of the Σ₆PAEs. Principal component analysis, positive matrix factorization, and correlation analysis were used to apportion the potential sources of PAEs in outdoor dust samples. The PAEs in the outdoor dust originated mainly from wide application of plasticizers as well as cosmetics and personal care products. The main pathways of human exposure to PAEs in the outdoor dust were ingestion and dermal absorption of dust particles. The total intakes of PAEs from outdoor dusts for children and adults were 1.50 × 10^-5 and 2.47 × 10^-6 mg·kg^-1·d^-1, respectively. Children were more susceptible to the PAEs intake than the adults. Although the estimated health risks of the six PAEs are currently acceptable, caution is needed given the likely future increase in use of these PAEs and the currently unknown contribution to human exposure by other medium.

Multiresidue analytical method for high production volume chemicals in dust samples, occurrence and human exposure assessment

A multiresidue analytical method based on pressurised liquid extraction and gas-chromatography mass spectrometry was developed to determine 22 compounds belonging to different chemical families in indoor dust.: Seven organophosphate esters, six phthalate esters, three benzotriazoles, five benzothiazoles and four benzenesulfonamides were included in the present study, all of them belonging to the category of high production volume chemicals (HPVCs). Apparent recoveries ranged between 45% and 123% and method quantification limits ranged from 0.03 μg/g to 3.8 μg/g. The occurrence of the selected HPVCs was evaluated in indoor dust from different locations in the Tarragona (Catalonia, Spain) region. Two benzenesulfonamides, ortho-toluenesulfonamide and para-toluenesulfonamide, were detected in dust samples for the first time. Phthalate esters and organophosphate esters were the most abundant compounds found, and di-(2-ethylhexyl) phthalate (DEHP) was determined at the highest concentrations. With the data obtained, human exposure was assessed by calculating the estimated daily intakes (EDI) via ingestion and dermal contact. Non-carcinogenic and carcinogenic risk assessments found no risks in any of the scenarios tested, which included two age classes (children and adults) and two possible exposure scenarios (median and worst-case scenario), except for the evaluation of carcinogen risk due to ingestion of DEHP in the worst-case scenario.

Emissions of Liquid Crystal Monomers from Obsolete Smartphone Screens in Indoor Settings: Characteristics and Human Exposure Risk

Liquid crystal monomers (LCMs) have been found to accumulate in indoor environments, but the emission kinetics of LCMs from electronic devices are not well understood. Leakage from damaged liquid crystal displays may be an important mechanism for LCMs to enter the environment and become potential health hazards to humans. To address this issue, we conducted chamber experiments to characterize the emissions of LCMs from obsolete smartphone screens and estimated the doses of residential and occupational exposures to LCMs. The emission rates of the detected LCMs were in the ranges of 0.1-7 μg m^-2 h^-1 at 80 °C, 0.05-7 μg m^-2 h^-1 at 60 °C, and 0.002-0.2 μg m^-2 h^-1 at 25 °C. Liquid crystal monomers with large molecular weights and low volatilities tended to accumulate at screen surfaces and were re-emitted at elevated temperatures, leading to high emission rates of heavy LCMs upon thermal treatment. The estimated doses of residential and occupational exposures to individual LCMs were 0.0001-0.009 and 0.007-2 ng kg^-1 d^-1, respectively. As LCMs are potentially carcinogenic based on in silico assessments, LCMs emitted from obsolete smartphones in indoor settings may become human health hazards.

Insights into photocatalytic degradation of phthalate esters over MSnO3 perovskites (M = Mg, Ca): Experiments and density functional theory

In this study, the physicochemical and photocatalytic properties of two kinds of stannate perovskite oxides (MgSnO₃ and CaSnO₃) were investigated under simulated sunlight, where dimethyl phthalate (DMP) and diethyl phthalate (DEP) were selected as the probe pollutants. The results of photochemical characterization showed that MgSnO₃ perovskite exhibited better photocatalytic performance than CaSnO₃ perovskite. MgSnO₃ perovskite could effectively degrade 75% of DMP and 79% of DEP through pseudo-first-order reaction kinetics, which remained good in pH 3.0 to 9.0. Quenching experiments and electron paramagnetic resonance (EPR) characterization indicated that photogenerated holes (h⁺), superoxide (O₂^-), and hydroxyl radicals (OH) worked in the photo-degradation, while O₂^- played the most important role. Furthermore, intermediates identification and density functional theory (DFT) calculations were used to explore the degradation mechanism. For both DMP and DEP, the reactive oxygen species (ROS, including O₂^- and OH) were responsible for the hydroxylation of benzene ring and the breaking of the aliphatic chain, while h⁺ was prone to break the aliphatic chain. This work is expected to provide new insights on the photocatalytic mechanism of stannate perovskites for environmental remediation.

Chronic inflammation as a potential mediator between phthalate exposure and depressive symptoms

BACKGROUND

A few studies have reported phthalate exposure as a risk factor for depressive symptoms, but the results have been inconsistent. Whether chronic inflammation mediates the relationship between phthalates (PAEs) and depressive symptoms remains unclear. In this study, we establish mediating models of inflammatory factors and explore the mediating role of chronic inflammation in the association between PAEs exposure and depressive symptoms.

METHODS

The sample included 989 participants from the Study on Health and Environment of the Elderly in Lu'an City, Anhui Province. Geriatric depression scale (GDS-30) was used to screen depressive symptoms of the elderly. The levels of seven kinds of PAEs in urine samples and four inflammatory factors in serum of the elderly were measured. To establish the mediating effect of inflammatory factors to explore the potential effect of PAEs exposure on the increased odds of depressive symptoms.

RESULTS

Adjusted for multiple variables, the highest tertiles of Mono (2-ethylhexyl) phthalate (MEHP) (95%CI = 1.051-2.112), Mono benzyl phthalate (MBzP) (95%CI = 1.016-2.082) and Mono butyl phthalate (MBP) (95%CI = 1.102-2.262) were positively correlated with depressive symptoms. The mediating effect of IL-6 and generalized inflammation factor between MEHP exposure and depressive symptoms were 15.96% (95%CI=0.0288-0.1971) and 14.25% (95%CI = 0.0167-0.1899).

CONCLUSIONS

High levels of MEHP, MBzP and MBP increased the odds of depressive symptoms in the elderly, and chronic inflammation had a partial mediating effect on the increased odds of depressive symptoms due to MEHP exposure.

An overview of organic contaminants in indoor dust, their health impact, geographical distribution and recent extraction/analysis methods

People spend a substantial proportion of their time indoors; therefore, exposure to contaminants in indoor dust is persistent and profuse. According to the findings of recent studies, contaminants such as flame retardants (FRs), organochlorines (OCs), and phthalate esters (PAEs) are more prevalent in indoor dust. The discrepancy in the geographical distribution of these chemicals indicates country-specific applications. However, many studies have revealed that chlorophosphates, polychlorinated biphenyls (PCBs) and di-2-ethylhexyl phthalate are frequently detected in indoor dust throughout the world. Although some chemicals (e.g., OCs) were banned/severely restricted decades ago, they have still been detected in indoor dust. These organic contaminants have shown clear evidence of carcinogenic, neurotoxic, immunogenic, and estrogenic activities. Recent extraction methods have shown their advantages, such as high recoveries, less solvent consumption, less extraction time and simplicity of use. The latest separation techniques such as two-dimensional gas/liquid chromatography, latest ionization techniques (e.g., matrix-assisted laser desorption/ionization (MALDI)), and modern techniques of mass spectrometry (e.g., tandem mass spectrometry (MS/MS), time-of-flight (TOF) and high-resolution mass spectrometry (HRMS)) improve the detection limits, accuracy, reproducibility and simultaneous detection of organic contaminants. For future perspectives, it is suggested that the importance of the study of dust morphology for comprehensive risk analysis, introducing standard reference materials to strengthen the analytical methods, adopt common guidelines for comparison of research findings and the importance of dust analysis in the developing world since lack of records on the production and usage of hazardous substances. Such measures will help to evaluate the effectiveness of prevailing legislations and to set up new regulations.

Contamination of typical phthalate acid esters in surface water and sediment of the Pearl River, South China: Occurrence, distribution, and health risk assessment

The occurrence and distribution of six phthalate acid esters (PAEs) in surface water and sediment of the Pearl River were investigated, including Xijiang River (XR), Beijiang River (BR), Lingdingyang Estuary (LE), and Guangzhou River (GR) in South China. Six target PAEs were identified in surface water and sediment at almost all sites in the Pearl River, with di(2-ethyl-ethyl) phthalate (DEHP) and dibutyl phthalate (DBP) as dominant PAEs. Total 6 PAEs (ΣPAEs) in surface water and sediment ranged from 1,797.5 to 4,968.5 ng L^-1 and 95.24 to 3,677.26 ng g^-1 dw, respectively. In addition, the contamination levels of PAEs in the Pearl River are in the following order: XR > BR > GR > LE for surface water and BR > XR > GR for sediment. Local agricultural activities, industrial production, water confluence, and seawater intrusion are the probable sources of PAEs in the Pearl River. Based on correlation analysis, the possible collocation patterns of different PAEs were revealed. The risk assessment indicates that residual PAEs in the Pearl River pose a serious threat to the ecological environment. According to risk characterization of fish living in the Pearl River, the decreasing order of health risks was: GR > LE > XR > BR.

Occurrence, spatial distribution and ecological risk assessment of phthalate esters in water, soil and sediment from Yangtze River Delta, China

A total of 96 water, soil, and sediment samples, collected from 32 sampling sites in the Yangtze River Delta (YRD) region, were analyzed for 9 phthalate esters (PAEs). The sum concentrations of 9 PAEs (∑₉PAEs) in the water, soil, and sediment samples were 2.23-6.30 μg L^-1 (mean: 4.11 μg L^-1), 155-1410 μg kg^-1 (408 μg kg^-1), and 30.1-16,000 μg kg^-1 (1200 μg kg^-1), respectively. Among the 9 PAEs, di-n-butyl phthalate (DBP), bis(2-ethylhexyl) phthalate (DEHP), and di-isobutyl phthalate (DIBP) are the predominant congeners in the YRD region. DBP was the dominant PAE congener in water, accounting for 50.6% of the Σ₉PAEs, while DEHP was the predominant one in soil and sediment (accounting for 69.6% and 83.1% of the Σ₉PAEs, respectively). Soil and sediment samples collected from Wuxi city manifested relatively higher PAE concentrations. The partitioning of PAEs between water and sediment was attributed to the fact that low molecular weight PAEs (e.g., dimethyl phthalate (DMP) and diethyl phthalate (DEP)) were dominant in water, medium molecular weight PAEs (e.g., BzBP) were close to the equilibrium between sediment-water, and high molecular weight PAEs (e.g., DEHP) were more prevalent in sediment. The ecological risk assessment of PAEs in the surface water showed that the potential environmental risks followed the order of DEHP > DIBP > DBP > DMP > DEP. Comparatively, DEHP posed high ecological risk to sensitive algae, crustaceans and fish, while DMP and DEP exhibited low risk. In the sediment, DIBP exhibited a high risk to the sensitive fish, whereas DMP, DEP, DBP and DEHP displayed no risk.

Phthalic acid esters (PAEs) in workplace and house dust from Vietnam: concentrations, profiles, emission sources, and exposure risk

The occurrence of nine phthalic acid esters (PAEs) were determined in indoor dust samples collected from vehicle repair shops, waste processing workshops, and homes in Vietnam. Concentrations of total PAEs ranged from 585 to 153,000 (median 33,400 ng/g), which fall in the lower end of global range. The PAE levels in workplace dust (median 49,100; range 9210-153,000 ng/g) were significantly higher than those in house dust (median 23,700; range 585-83,700 ng/g), indicating waste processing activities as potential PAE sources. The most predominant compound was di-(2-ethyl)hexyl phthalate (DEHP), accounting for 62 ± 18% of total PAEs. Other major compounds were benzyl butyl phthalate (BzBP) (10 ± 12%), di-n-butyl phthalate (DnBP) (9.7 ± 7.7%), di-n-octyl phthalate (DnOP) (7.9 ± 8.1%), and diisobutyl phthalate (DiBP) (6.9 ± 5.0%). Proportions of BzBP and DnBP in some workplace dust samples were markedly greater than in common house dust, suggesting specific emission sources. Daily intake doses of selected PAEs (e.g., DnBP, DiBP, BzBP, and DEHP) through dust ingestion were much lower than reference doses, implying acceptable levels of risk.

Geographic distribution and time trend of human exposure of Di(2-ethylhexyl) phthalate among different age groups based on global biomonitoring data

Despite being restricted by many authorities, di (2-ethylhexyl) phthalate (DEHP) is still widely detected in the environment and biospecimens. To indentify populations of high risk and evaluate the effects of DEHP restrictions, we elucidated the geographic distribution of DEHP exposure levels among pregnant women and different age groups, and compared the time trend of exposure levels with the time course of productions/restrictions. The estimated daily intake (EDI) was calculated based on biomonitoring data in published epidemiological studies, and then the group EDI (EDI_G) was calculated for one particular population, region, or period by weighting EDIs by sample sizes. Overall, 144,965 samples from 45 nations were included, with the sampling time ranging from 1982 to 2017. Children had the highest exposure level (5.50 μg/kg bw/day) worldwide, while infants and pregnant women had low levels (2.13 and 1.89 μg/kg bw/day, respectively). The EDI_Gs varied considerably between countries, and the majority of corresponding hazard quotients were less than 1; however, the risk behind can not be ignored. In the general population, the DEHP exposure level showed a downtrend from 4.40 μg/kg bw/day before 2000 to 2.23 μg/kg bw/day in 2015-2017. In the European Union, the annual trend of DEHP EDI_Gs of children and adults fitted the production and consumption volume, and the EDI_Gs decreased more sharply in children. The EDI_Gs of children decreased with a delay along with the regulations on the use of DEHP. Cutting productions/consumptions and restrictions are effective to reduce DEHP exposure, but current efforts are far from enough on a worldwide scale.

Associations between phthalic acid esters in house dust and home characteristics/living habits in a rural region of Taiwan

Phthalic acid esters (PAEs) commonly used as plasticizers are distributed ubiquitously in the living environment. We conducted a field study to examine the associations between PAE residue in dust and home characteristics/living habits in 47 rural homes in Taiwan. A questionnaire regarding home characteristics/living habits and composite sampling of house dust were conducted in each participating home. Five PAEs were selected for analysis on gas chromatography-mass spectrometry with the limits of quantification being 0.5 ng/g or lower. Uni- and multivariate linear regression analyses were performed for examining the associations. The five PAEs were prevalently detected from the samples, and the concentrations were below 1000 ng/g; di(2-ethylhexyl) phthalate (DEHP) was the most frequently detected PAE (85%), whereas di-isobutyl phthalate (DiBP) appeared to the most abundant congener with the maximum concentration of 807.65 ng/g. Floor cleaning frequency and use of detergents for floor cleaning were significantly associated with DEHP in dust (P < 0.05), suggesting additives of plasticizers in detergent products. The factors of plastic wraps in storage and use of disposable cups were both significantly related to DiBP (P < 0.01), which could be extensively used in food packaging products. We confirmed that several home characteristics/living habits were related to certain PAE residue in dust.

Occurrence of parabens, triclosan and triclocarban in paired human urine and indoor dust from two typical cities in China and its implications for human exposure

Parabens, triclosan (TCS) and triclocarban (TCC) are emerging endocrine disrupting chemicals, which are commonly used in personal care products and household applications in daily life. Due to their adverse health effects, human exposure to these chemicals has been a public concern. Despite evidence showing different exposure pathways of these chemicals, few studies have examined contribution of certain exposure to total human exposure. In this study, we measured six parabens, TCS and TCC in 129 indoor dust samples and these chemicals plus four paraben metabolites in 203 urine samples from two different cities in China (Suizhou, a typical small city in central China and Beijing, the capital of China). The median concentrations of ∑₆Parabens (1050 ng/g) and ∑TCS + TCC (565 ng/g) in dusts from Beijing were 1.9-3.3 times higher than those from Suizhou (∑₆Parabens: 314, ∑TCS + TCC: 294 ng/g). The ∑₆Parabens in urines from Suizhou and Beijing were in the range of 0.208-645 and 0.455-2300 μg/g Creatinine (Cr), respectively. The ∑TCS + TCC concentrations in urine were 1-2 orders of magnitude lower than those found for ∑₆Parabens. Comparatively, women had relatively higher body burden of parabens than men, which was more noticeable when considering the use of skin care products. In this regard, relatively higher levels of parabens were also found in women in couples. Positive correlations were found between concentrations of methyl-paraben (MeP) and ethyl-paraben (PrP) in paired dust and urine samples (p < 0.05). Human exposure to such chemicals was evaluated. Based on the measured concentrations in paired human urine and indoor dust samples, our results provided direct evidence that the contribution of indoor dust ingestion to the total exposure was minor. These findings are essential for clarifying the sources and potential exposure routes of these chemicals in humans.

Prevalence of phthalate alternatives and monoesters alongside traditional phthalates in indoor dust from a typical e-waste recycling area: Source elucidation and co-exposure risk

This study first discovered the prevalence of phthalate (PAE) alternatives and PAE monoesters alongside traditional PAEs with elevated concentrations in indoor dust from typical e-waste recycling industrial park and adjacent communities. Among nine PAEs, high-molecular-weight (HMW) PAEs dominated over low-molecular-weight (LMW) PAEs in e-waste dust, with total concentrations (∑₉PAEs) ranging from 170 to 5300 μg g^-1. The diisononyl phthalate (DiNP) was identified as the most abundant PAE in e-waste dust, with over 10 times higher median concentration than that measured in home dust. Total concentrations of three PAE alternatives ranged from 20 to 1600 μg g^-1 in e-waste dust, which were 3-10 times higher than the measured levels in home dust. A total of 13 monoesters were all identified in all samples with total concentrations of 4.7-59 μg g^-1, and biodegradation of diesters was recognized as the major source of monoesters present in indoor dust. Significant correlations between the concentrations of PAE alternatives and the HMW PAEs were observed (p < 0.05), indicating that they are being simultaneously used in electronic and electrical products. The occupationally high co-exposure of e-waste dismantling workers to multiple PAEs and PAE alternatives as well as their monoesters should be of concern.

Insights into mechanisms involved in the uptake, translocation, and metabolism of phthalate esters in Chinese cabbage (Brassica rapa var. chinensis)

In the present study, the uptake and translocation mechanisms of phthalate esters (PAEs) and their primary mono esters metabolites (mPAEs), and the mechanisms of PAEs metabolism in plants were elucidated. The objectives of this study were to: (i) elucidate the fractionation of PAEs and mPAEs in Chinese cabbage (Brassica rapa var. chinensis) by hydroponic experiment, (ii) investigate the PAEs and mPAEs uptake mechanisms in root by inhibitor experiments, (iii) explain the molecular mechanisms of PAE interactions with the plant macromolecules by proteomics analysis and molecular docking, and (iv) reveal the involvement of carboxylesterase in the plant metabolism of PAEs. The results demonstrated that both the apoplastic and symplastic pathways contributed to the uptake of di-n-butyl phthalate (DnBP), di-(2-ethylhexyl) phthalate (DEHP), mono-n-butyl phthalate (MnBP), and mono-(2-ethylhexyl) phthalate (MEHP) by vacuum-infiltration-centrifugation method. The energy-dependent active process was involved for the uptake of DnBP, DEHP, MnBP, and MEHP. The passive uptake pathways of anion mPAEs and neutral PAEs differ. Aquaporins contributed to the uptake of anion MnBP and MEHP, and slow-type anion channel was also responsible for the uptake of anion MEHP. Molecular interactions of PAEs and macromolecules were further characterized by proteomic analysis and molecular docking. PAEs were transferred via non-specific lipid transfer protein by binding hydroponic amino acid residues. The carboxylesterase enzyme was attributed to the metabolism of PAEs to form mPAEs by using crude enzyme extract and commercial pure enzyme. This study provides both experimental and theoretical evidence for uptake, accumulation, and metabolism of PAEs in plants.

Di-(2-ethylhexyl) phthalate induces testicular endoplasmic reticulum stress and germ cell apoptosis in adolescent mice

Di-(2-ethylhexyl) phthalate (DEHP) is a male reproductive toxicant. This research is aimed at investigating the effect of pubertal DEHP exposure on testicular endoplasmic reticulum (ER) stress and germ cell apoptosis. Five-week-old male mice were orally administered with DEHP (0, 0.5, 50, or 500 mg/kg/day) for 35 days. Testis weight and sperm count were reduced in mice exposed to 500 mg/kg/day DEHP. The number of seminiferous tubules in stages VII-VIII, mature seminiferous tubules, was reduced and the number of seminiferous tubules in stages IX-XII, immature seminiferous tubules, was elevated in mice treated with 500 mg/kg/day DEHP. Numerous apoptotic germ cells were observed in mouse seminiferous tubules exposed to 50 and 500 mg/kg/day DEHP. Moreover, cleaved caspase-3 was elevated in mouse testes exposed to 500 mg/kg/day DEHP. In addition, Bcl-2 was reduced and Bax/Bcl-2 was elevated in mouse testes exposed to 500 mg/kg/day DEHP. Additional experiment showed that GRP78, an ER molecular chaperone, was downregulated in mouse testes exposed to 500 mg/kg/day DEHP. Testicular p-IRE-1α, p-JNK, and CHOP, three markers of ER stress, were upregulated in mice exposed to 500 mg/kg/day DEHP. These results suggest that pubertal exposure to high doses of DEHP induces germ cell apoptosis partially through initiating ER stress in testes.

Phthalates in House and Dormitory Dust: Occurrence, Human Exposure and Risk Assessment

Phthalates are one of ubiquitous contaminants in the indoor environment. In this study, we analyzed concentrations and profiles of 9 phthalates in dust samples collected from houses and university dormitories in Nanjing, China. The total concentrations of phthalates in house and dormitory dust ranged from 111.4 to 3599.1 µg/g and 86.1 to 1262.3 µg/g, respectively. Phthalates in house was significantly higher than that in dormitory dust (p < 0.01). Di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP) and di-isobutyl phthalate (DiBP) were the three predominant compounds and accounted for more than 98% of total phthalates in the two microenvironments. The estimated daily intake (EDI) of phthalates, carcinogenic risk (CR) of DEHP, and hazard index (HI) values of DEHP, DBP and DiBP were estimated. Except for adults, the CR of DEHP for four subgroups (infants, toddlers, children, and teenagers) had exceeded the limitation, implying that they are at the risk of exposure to DEHP through dust ingestion.

Pollution characteristics, sources, and health risk of atmospheric phthalate esters in a multi-function area of Hangzhou, China

Phthalate esters (PAEs) are widely used in the manufacturing of plastics, and their demands have grown rapidly, especially in China, which will lead to much more environmental pollution of PAEs. In this study, fourteen common PAEs in ambient air were investigated during non-typhoon and typhoon seasons in a mixed multi-functional area of Hangzhou, China. The average concentrations of ∑₁₄ PAEs in gaseous and PM_2.5-bound phase (G-PAEs and P-PAEs) were 2317 ng/m³ and 128 ng/m³ during sampling period, while the mean concentrations of total PAEs in non-typhoon and typhoon seasons were 2412 ng/m³ and 2183 ng/m³, respectively. Bis(2-ethylhexyl)phthalate (DEHP) was the most abundant one, averagely accounting for 63.2% of G-PAEs and 88.3% of P-PAEs. Relative humidity showed a significant negative correlation with short-chain PAE (r = - 0.479, P < 0.01) and long-chain PAE (r = - 0.305, P < 0.05) concentrations in non-typhoon and typhoon seasons, and O₃ could degrade G-PAEs through photoreaction. Source identification by the positive matrix factorization model and conditional probability function indicated that P-PAEs were mainly from the release from indoor environment (43%), PVC source (34%), construction source (12%), and industry source (11%). Air mass transport from both inland and oceans affected the PAE pollution in non-typhoon season, while its long-range transport from oceans took an important role in typhoon season. The daily inhalation intakes of PAEs for infants, teenagers, and adults were estimated, which showed that infants experienced the highest exposure risk.

Occurrence, fate, and risk assessment of typical tetracycline antibiotics in the aquatic environment: A review

Tetracyclines (TCs), used as human and veterinary medicines, are the most widely used antibiotics. More than 75% of TCs are excreted in an active form and released into the environment through human and animal urine and feces, causing adverse effects on the ecological system and human health. Few articles review the environmental occurrence and behaviors of TCs, as well as their risks and toxicities. Here, we comprehensively summarized the recent advances on the following important issues: (1) Environmental occurrence of TCs. TCs are used globally and their occurrence in the aquatic environment has been documented, including surface water, groundwater, drinking water, wastewater, sediment, and sludge. (2) Environmental behaviors of TCs, particularly the fate of TCs in wastewater treatment plants (WWTPs). Most WWTPs cannot effectively remove TCs from wastewater, so alternative methods for efficient removal of TCs need to be developed. The latest degradation methods of TCs are summarized, including adsorption, photocatalytic, photochemical and electrochemical, and biological degradations. (3) Toxicities and possible risks of TCs. The toxicological data of TCs indicate that several TCs are more toxic to algae than fish and daphnia. Risk assessments based on individual compound exposure indicate that the risks arising from the current concentrations of TCs in the aquatic environment cannot be ignored.

Occurrence, distribution and human exposure of phthalic esters in road dust samples across China

203 road dust samples were conducted across China covering 28 provinces from January to February，2016 to comprehensively investigates the occurrence, distribution and human exposure of 21 phthalic esters (PAEs). The concentration of Σ₂₁PAEs in road dust ranged from 2.3 to 531 mg/kg, with a mean concentration of 64.1 ± 57.2 mg/kg. DEHP, DnBP and DiBP were the dominant components accounting for 63.3-97.9% (mean: 92.1%) of the Σ₂₁PAEs. Significant Pearson correlation (r = 0.51, p < 0.0001) between Σ₂₁PAEs concentrations and longitude demonstrated a distinguished geographical trend. Higher concentration of PAEs in sidewalk (SW) and trunk road (TR) may reflect influence of human activities such as shoe wear and traffic load. Significant differences were found among different human activities area (urban commercial, urban residential, and suburbs/rural). For total daily intake of Ʃ₂₁PAEs via street dust, children had the highest exposure risk followed by teenagers and adults with the median values of 160.8, 43.6, and 37.7 ng/kg-bw/day, respectively. The maximum exposure risk of PAEs calculated based on measurement and simulation were all far below reference values. The sensitivity analysis results demonstrated that concentrations, ingestion rate (IR) and fraction of PAEs absorbed in the skin (AF) were most important parameters on the assessment of exposure risk of PAEs via street dust. Specific parameters based on China and Chinses population is needed to obtain more reliable exposure risk via street dust.

Comparative uptake, translocation and subcellular distribution of phthalate esters and their primary monoester metabolites in Chinese cabbage (Brassica rapa var. chinensis)

Phthalates esters (PAEs) are ubiquitous contaminants in terrestrial system and PAEs can be degraded to monoester metabolites (mPAEs) both in soil and plants, which have equal or even greater biological activity compared to their parent compounds. Until now, little is known about the comparative uptake and translocation of PAEs and mPAEs in plants. In the present study, the uptake and translocation of two commonly used plasticizers, di-n-butyl phthalate (DnBP) and di-(2-ethylhexyl) phthalate (DEHP), and the corresponding mPAEs, mono-n-butyl phthalate (MnBP) and mono-(2-ethylhexyl) phthalate (MEHP) by Chinese cabbage (Brassica rapa var. chinensis) were examined using hydroponic experiment. Significantly lower bioconcentration factors (BCFs) of mPAEs compared to the corresponding PAEs were observed. This is likely due to the great solubility and electrical repulsion from cell membrane to mPAE anions. Comparatively low translocation factors (TFs) of MnBP (7.76 ± 0.49) were observed compared to DnBP (10.33 ± 2.83); while the TFs of MEHP (0.18 ± 0.08) were significantly greater than that of DEHP (0.05 ± 0.02). The hydrophilic mPAEs are prone to concentrate in cell water-soluble components, and DnBP was relatively uniformly distributed in cell wall and cell water-soluble components; while the more hydrophobic DEHP was mainly associated with root cell wall. The formation of mPAEs occurred mainly in the above-ground tissues in the PAEs spiked treatment, and cell water-soluble compartment was the main location for PAEs metabolism. The high metabolite/parent ratios in Chinese cabbage indicate that more concern should be directed towards metabolites associated with plants via direct uptake and plant metabolism.

Infantile phthalate metabolism and toxico/pharmacokinetic implications within the first year of life

BACKGROUND

Infantile development of phthalate metabolism is crucial for risk assessment of endocrine disruption and has important toxico/pharmacokinetic implications.

OBJECTIVES

To characterize temporal variability in urinary phthalate metabolites in infants and to examine their growth-dependent detoxification.

METHODS

In this cohort study, urine samples (n = 876) from 155 healthy Chinese infants were collected serially at eight time points from birth to one year old. Free and total (i.e., free plus glucuronide conjugated) phthalate metabolites (PMEs) were measured by LC/MS/MS. Time variability in PMEs and PME metabolism capacity was characterized using intraclass correlation coefficients (ICCs) and linear mixed regression models.

RESULTS

Concentrations of most PMEs changed significantly, with ICCs ranging from 0.213 to 0.318, and trends increased significantly over time (p < 0.001), while MEHP showed fair reproducibility (ICC = 0.480). Glucuronidation increased considerably (ICC ≤ 0.250; p < 0.001) for most PMEs but not for MMP or MEHP. Ester-chain ω-/ω-1-oxidation and α-/β-oxidation patterns of MEHP steeply increased from 3 months to 8 months, where they peaked, resulting in a molar percentage of MEHP in ΣDEHP showing the inversion pattern. MEHP detoxification through oxidation of the hydrophobic ester-chain is apparently a priority for carboxyl glucuronidation in infants.

CONCLUSIONS

Infant phthalate exposure is prevalent, but they cannot metabolize or eliminate these compounds as efficiently as adults, especially during the first 6 months of life. From an environmental biomonitoring view, age-dependent phthalate metabolism provides crucial implications for infantile ontogeny and health risk assessment within the first year of life.

Occurrence, Distribution, and Human Exposure of Several Endocrine-Disrupting Chemicals in Indoor Dust: A Nationwide Study

Parabens, triclosan (TCS), triclocarban (TCC), and bisphenol A and its analogues (BPs) are used in various industrial and consumer products and are typical endocrine-disrupting chemicals (EDCs). In this study, six parabens, TCS, TCC, and eight BPs were determined in 289 indoor dusts collected from different geographical regions in China. Ten of 16 target compounds were found in >50% samples. Concentrations of Σ₆parabens, Σ(TCS+TCC), and Σ₈BPs in indoor dust ranged from 8.66-21,500 (median: 288), 19.6-8940 (104), and 8.80-37,400 (377) ng/g dw, respectively. The Σ(TCS+TCC) concentrations in dust from Northeast China were higher than those from Central South China (p < 0.05). The concentrations of Σ₈BPs in dust from Eastern China were approximately 2 times higher than those found for North China (p < 0.05), whereas there was no significant spatial difference in concentrations of parabens among different geographical regions (p > 0.05). Human exposure to these EDCs through indoor dust ingestion and dermal absorption was evaluated. The median and 95th percentile estimated daily intakes of Σ₁₆EDCs ranged from 0.439 (adults)-4.57 (infants) and 6.26 (adults)-62.1 (infants) ng/kg bw/day, respectively, generally decreasing with increasing age. This nationwide survey establishes a baseline concentration for parabens in the indoor environment in China.

Phthalate exposure in Chinese homes and its association with household consumer products

Phthalates are SVOCs (Semi-volatile Organic Compounds) that are widely used in industrial and daily home products. This study aimed to investigate exposure levels to phthalates in Chinese homes and to relate these to building characteristics and lifestyles. Dust in 399 homes of 410 children in urban Tianjin and rural Cangzhou was analyzed for concentrations of six target phthalates. The median concentrations were 0.31μg/g for diethyl phthalate (DEP), 16.39μg/g for di-isobutyl phthalate (DiBP), 42.60μg/g for di-n-butyl phthalate (DnBP), 0.10μg/g for benzyl butyl phthalate (BBzP), 127.11μg/g for di (2-ethylhexyl) phthalate (DEHP) and 0.28μg/g for di-isononyl phthalate (DiNP). Strong associations were found between modern flooring materials (laminated wood/wood) and concentrations of DiBP, BBzP and DiNP; modern window frame (aluminum/plastic steel) and BBzP concentration; leather polish and DEHP concentration; perfume and DEP concentration. Concentrations of phthalates were significantly higher in Tianjin urban homes than Cangzhou rural homes. Concentrations of phthalates increased significantly with increasing household income. Our study indicates that exposure to phthalates in Chinese homes increases with attributes of modern life.

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.

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.