Analysis and health risk assessment of phthalate esters (PAEs) in indoor dust of preschool and elementary school centers in city of Tehran, Iran

A systematic review of global distribution, sources and exposure risk of phthalate esters (PAEs) in indoor dust

Phthalate esters (PAEs) are a class of plasticizers that are readily released from plastic products, posing a potential exposure risk to human body. At present, much attention is paid on PAE concentrations in indoor dust with the understanding of PAEs toxicity. This study collected 8187 data on 10 PAEs concentrations in indoor dusts from 26 countries and comprehensively reviewed the worldwide distribution, influencing factors, and health risks of PAEs. Di-(2-ethylhexyl) phthalate (DEHP) is the predominant PAE with a median concentration of 316 μg·g-1 in indoor dust. Polyvinyl chloride wallpaper and flooring and personal care products are the main sources of PAEs indoor dust. The dust concentrations of DEHP show a downward trend over the past two decades, while high dust concentrations of DiNP are found from 2011 to 2016. The median dust contents of 8 PAEs in public places are higher than those in households. Moreover, the concentrations of 9 PAEs in indoor dusts from high-income countries are higher than those from upper-middle-income countries. DEHP in 69.8% and 77.8% of the dust samples may pose a potential carcinogenic risk for adults and children, respectively. Besides, DEHP in 16.9% of the dust samples may pose a non-carcinogenic risk to children. Nevertheless, a negligible risk was found for other PAEs in indoor dust worldwide. This review contributes to an in-depth understanding of the global distribution, sources and health risks of PAEs in indoor dust.

Dust dynamics: distribution patterns of semi-volatile organic chemicals across particle sizes in varied indoor microenvironments

An extensive analysis of the distribution patterns of three distinct classes of semi-volatile organic chemicals (SVOCs)-phthalates (PAEs), organophosphate flame retardants (OPFRs), and polycyclic aromatic hydrocarbons (PAHs)-across four distinct size fractions of dust (25, 50, 100, and 200 μm) was conducted. The dust samples were sourced from AC filter, covered car parking lots, households, hotels, mosques, and car floors. To generate the four fractions, ten dust samples from each microenvironment were pooled and sieved utilizing sieving apparatus with the appropriate mesh size. Selected SVOCs were quantified utilizing gas chromatography-mass spectrometry in electron impact (EI) mode. Results unveiled diverse contamination levels among dust fractions, showcasing car parking lot dust with the lowest chemical contamination, while car floor dust displayed the highest levels of PAHs and OPFRs, peaking at 28.3 µg/g and 43.2 µg/g, respectively. In contrast, mosque and household floor dust exhibited the highest concentrations of phthalates, with values of 985 µg/g and 846 µg/g, respectively. Across the analyzed microenvironments, we observed a trend where concentrations of SVOCs tended to rise as dust particles decreased in size, forming a visually striking pattern. This phenomenon was particularly pronounced in dust samples collected from car floors and parking lots. Among SVOCs, PAEs emerged as the predominant contributors with > 90% followed by OPFRs and PAHs. The high levels of OPFRs in car floor dust align logically with the fact that numerous interior components of cars are treated with OPFRs, within a compact indoor microenvironment, to comply to fire safety regulations. Furthermore, petroleum products are a major source of PAHs in the environment and all the sampled cars in the study had combustion engines. Consequently, car dust is more likely to be polluted with PAHs stemming from petroleum combustion. Although previous investigations have noted an increase in heavy metals and brominated flame retardants with decreasing dust particles, this is the first study analyzing these SVOCs in different fractions of dust from various microenvironments. However, aside from two specific microenvironments, the observed pattern of escalating SVOC concentrations with smaller dust particle sizes was not corroborated among the examined microenvironments. This divergence in concentration trends suggests the potential involvement of supplementary variables in influencing SVOC distributions within dust particles.

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.

Dust-phase phthalates in university dormitories in Beijing, China: pollution characteristics, potential sources, and non-dietary oral exposure

This study aimed to determine dust-phase phthalate levels in 112 dormitories of 14 universities during autumn and winter, investigate their potential sources, and estimate phthalate exposure via dust ingestion. Twelve phthalates were detected, among which di-(2-ethylhexyl) phthalate (DEHP) and dicyclohexyl phthalate (DCHP) were the most abundant, followed by di-isobutyl phthalate (DiBP) and di-n-butyl phthalate (DnBP). The median concentrations and contributions of DCHP and DEHP were the highest. The contributions of di-n-octyl phthalate and di-nonyl phthalate were higher in winter than in autumn. Potential sources included iron furniture, chemical fiber textiles, clothes, and personal care products. Medium-density fiberboard furniture is a potential sink for phthalates. In two seasons, DEHP, DCHP, DiBP, and DnBP were the main phthalates ingested by college students . The median oral exposure of ten phthalates was higher in females than in males. College students have a high risk of exposure to DEHP in dormitories.

Dust phase and window film phase phthalates in dormitories: profile characteristics, source screening, and estimated gas-phase concentration and dermal exposure comparison

Recently, phthalate exposure has become a major public health concern. However, gaps still remain in our understanding of phthalate profile characteristics, source screening, and gas-phase estimation. This study measured phthalate concentrations in dust and window films in 101 dormitories at 13 universities in Beijing, China, from October to December 2019. Based on the phthalate concentrations in the dust and window films, we estimated the gas-phase phthalate concentrations using steady-state and instantaneous equilibrium models, respectively, and male and female students' dermal exposure using the Monte Carlo simulation. Commonly used materials and supplies were screened for phthalate sources and evaluated using the positive matrix factorization (PMF) model. The results showed that the detection frequency of ten phthalates ranged from 79.2 to 100% in dust and from 84.2 to 100% in window films. Dicyclohexyl phthalate (DCHP), di-(2-ethylhexyl) phthalate (DEHP), and dibutyl phthalate (DBP) were the most abundant phthalates in both indoor media and were also predominant in the indoor materials and supplies. The PMF results indicated that the potential sources of phthalates in dust and window films had both similarities and differences. Indoor door seals, paint, coatings, cables, air-conditioning rubber cable ties, wallpaper, and window seals were highly probable sources of phthalates. The gas-phase phthalate concentrations estimated using the two methods differed, especially for phthalates with high octanol-air partition coefficients (Koa), varying by 1-2 orders of magnitude. Moreover, compared with related studies, the gas-phase concentrations were significantly underestimated for phthalates with high Koa values, while the estimated gas-phase concentrations of phthalates with low Koa values were closer to the measured values. The estimated dermal exposure using the two methodologies also considerably differed. Such findings suggest that more attention should be focused on the exposure risk from the dust phase and window film phase phthalates.

Comprehensive assessment of phthalates in indoor dust across China between 2007 and 2019: Benefits from regulatory restrictions

China is the largest producer and consumer of phthalates in the world. However, it remains unclear whether China's phthalate restrictions have alleviated indoor phthalate pollution. We extracted the concentrations of dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), benzyl butyl phthalate (BBP), and bis(2-ethylhexyl) phthalate (DEHP) in indoor dust at 2762 sites throughout China between 2007 and 2019 from the published literature. Based on these data, we investigated the effects of phthalate restrictions and environmental factors on the temporal-spatial distribution and sources of phthalates and estimated human exposure and risk of phthalates. The results revealed that the mean concentrations of phthalates in indoor dust throughout China decreased in the following order: DEHP > DBP > DIBP > DMP > DEP > BBP. The concentrations of six phthalates were generally higher in northern and central-western China than in southern regions. BBP and DEHP concentrations decreased by 73.5% and 17.9%, respectively, from 2007 to 2019. Sunshine was a critical environmental factor in reducing phthalate levels in indoor dust. Polyvinyl chloride materials, personal care products, building materials, and furniture were the primary sources of phthalates in indoor dust. The phthalates in indoor dust posed the most significant threat to children and older adults. This study provides a picture of phthalate pollution, thus supporting timely and effective policies and legislation.

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.

Contaminant occurrence, distribution and ecological risk assessment of phthalate esters in the Persian Gulf

Due to the increasing population of the world, the presence of harmful compounds, especially phthalate esters (PAEs), are one of the important problems of environmental pollution. These compounds are known as carcinogenic compounds and Endocrine-disrupting chemicals (EDCs) for humans. In this study, the occurrence of PAEs and the evaluation of its ecological risks were carried out in the Persian Gulf. Water samples were collected from two industrial sites, a rural site and an urban site. Samples were analyzed using magnetic solid phase extraction (MSPE) and gas chromatography-mass spectrometry (GC/MS) technique to measure seven PAEs including Di(2-ethylhexyl) phthalate (DEHP), butyl benzyl phthalate (BBP), diethyl phthalate (DEP), dibutyl phthalate (DBP), Dimethyl phthalate (DMP), di-n-octyl phthalate (DNOP), and Di-iso-butyl phthalate (DIBP). The BBP was not detected in any of the samples. The total concentration of six PAEs (Σ6PAEs) ranged from 7.23 to 23.7 μg/L, with a mean concentration of 13.7μg/L. The potential ecological risk of each target PAEs was evaluated by using the risk quotient (RQ) method in seawater samples, and the relative results declined in the sequence of DEHP >DIBP > DBP > DEP > DMP in examined water samples. DEHP had a high risk to algae, crustaceans and fish at all sites. While DMP and DEP showed lower risk for all mentioned trophic levels. The results of this study will be helpful for the implementation of effective control measures and remedial strategies for PAEs pollution in the Persian Gulf.

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.

Associations of exposure to melamine, cyanuric acid, phthalates with markers of early kidney impairment, and their interactions in US adults: analyses of NHANES 2003-2004 data

Melamine (MEL), cyanuric acid (CYA), and phthalates have kidney toxicity, respectively. Still, no study has explored whether there is an interaction of co-exposure to MEL, CYA, and phthalates on early kidney impairment, including cystatin C (CYST), beta 2-microglobulin (β2-MG), albumin creatinine ratio (ACR), and estimated glomerular filtration rate (eGFR). Urine samples were collected from 333 adults in the National Health and Nutrition Examination Survey (NHANES) 2003-2004, and urinary MEL, CYA, and ten metabolites of phthalates were quantified. The multiple markers of early kidney impairment were also measured, including serum CYST, β2-MG, urinary ACR, and eGFR. Their associations were explored by multiple linear and multivariate logistic regression models. Meanwhile, the interactions of co-exposure to MEL, CYA, and phthalates on early kidney impairment were analyzed by Wilcoxon rank-sum test combined with the LSD test. In the multiple linear regression model, urinary concentrations of monobenzyl phthalate (MBzP), mono(3-carboxypropyl) phthalate (MCPP), mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), and mono(2-ethylhexyl) phthalate (MEHP) were positively associated with urinary ACR, serum β2-MG, and CYST, respectively. Urinary concentrations of MBzP and MCPP were negatively associated with eGFR. In the multivariate logistic regression model, increased urinary CYA concentration was the risk factor of CYST abnormality with an odds ratio (OR) (95% confidence interval, 95% CI) of 2.38 (1.01, 5.60) (P = 0.047) and increased urinary MBzP concentration was the risk factor of ACR abnormality with an OR of 2.59 (1.41, 4.75) (P = 0.002). The co-exposure to MEL, CYA, and four phthalate metabolites (MEHP, MBzP, MCPP, and MECPP) presented significantly interactive effects on the markers of early kidney impairment, respectively. There were the independent and interactive effects of exposure to MEL, CYA, and specific phthalate metabolites on early kidney impairment. Due to co-exposure to multiple environmental chemicals in our daily life, more attention should be paid to the health damage raised by the synergistic effects of environmental chemicals.

Exposure characteristics of phthalate metabolites among the Zunyi cohort of pregnant women in Southwest China

Reported evidence has increasingly indicated that exposure to phthalates can cause adverse pregnancy outcomes. However, phthalate exposure levels among pregnant women remains unclear. We aimed to evaluate the concentrations and predictors of phthalate metabolites in urine samples of the ongoing Zunyi cohort of pregnant women from Southwest China. The urine samples were collected from 1003 pregnant women during their third trimester of pregnancy. The concentrations of nine phthalate metabolites in urine samples were then determined. Data on socio-demographic profiles of the participants, lifestyle during pregnancy, parity, and sampling season were collected using questionnaires. The detectable rate of phthalate metabolites ranged from 76 to 100%. On average, mono-butyl phthalate exhibited the highest median concentration (62.45 μg/L), while mono-benzyl phthalate exhibited the lowest median concentration (0.04 μg/L). Urine concentrations of phthalate metabolites were significantly higher in older, multiparous, higher body mass index, higher income, and passive smoking during pregnancy participants. The levels of low-molecular-weight phthalate metabolites were highest during the summer. The findings indicate the health of pregnant women and fetuses in Zunyi may be generally harmed by the high exposure of phthalate metabolites, especially by mono-n-butyl phthalate. In addition, phthalate metabolites present a demographic and seasonal differential distribution among the study population. Targeted measures to reduce phthalate exposure for high-risk pregnant women and during high-exposure seasons may have potential benefits for maternal and fetal health protection.

The Association between Daily Dietary Intake of Riboflavin and Lung Function Impairment Related with Dibutyl Phthalate Exposure and the Possible Mechanism

This study aimed to evaluate the relationship between the daily dietary intake of riboflavin (DDIR) and impaired lung function associated with dibutyl phthalate (DBP) exposure. Data of 4631 adults in this national cross-sectional survey were included. Urinary mono-benzyl phthalate (MBP) was used to evaluate the level of DBP exposure. The ln-transformed urinary creatinine-corrected MBP (ln(MBP/UCr)) level was used in the statistical models. High DDIR was defined as the DDIR ≥1.8 mg per day. The results of lung function impairment and high monocytes were significantly higher in the highest MBP group compared with the lowest MBP group. A significant interaction between ln(MBP/UCr) and DDIR (P_interaction = 0.029) was detected for the risk of lung function impairment. The risk of lung function impairment (OR_{quartiles4 vs. 1} 1.85, 95% CI, 1.27–2.71; P_trend = 0.018) and high neutrophils (OR_{quartiles4 vs. 1} 1.45, 95% CI, 1.06–1.97; P_trend = 0.018) was significantly higher in the highest vs. the lowest quartile of MBP in participants with low/normal DDIR but not in in participants with high DDIR. The results of this study showed that high DDIR was associated with less lung function impairment related with DBP exposure, and the inhibiting of the neutrophil recruitment might be the potential mechanism.