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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. [ABSTRACT FROM AUTHOR]

River water plays a critical role in riparian plant water use and riparian ecosystem restoration along losing rivers (i.e., river water recharging underlying groundwater). How to quantify the contributions of river water to the transpiration of riparian plants under different groundwater levels and the related responses of plant water use efficiency is a great challenge. In this study, observations of stable isotopes of water (δ2H and δ18O), 222Rn , and leaf δ13C were conducted for the deep-rooted riparian weeping willow (Salix babylonica L.) in 2019 (dry year) and 2021 (wet year) along the Chaobai River in Beijing, China. We proposed an iteration method in combination with the MixSIAR model to quantify the river water contribution to the transpiration of riparian S. babylonica and its correlations with the water table depth and leaf δ13C. Our results demonstrated that riparian S. babylonica took up deep water (in the 80–170 cm soil layer and groundwater) by 56.5 % ± 10.8 %. River water recharging riparian deep water was an indirect water source and contributed 20.3 % of water to the transpiration of riparian trees near the losing river. Significantly increasing river water uptake (by 7.0 %) and decreasing leaf δ13C (by - 2.0 ‰) of riparian trees were observed as the water table depth changed from 2.7 m in the dry year of 2019 to 1.7 m in the wet year of 2021 (p<0.05). The higher water availability probably promoted stomatal opening and thus increased transpiration water loss, leading to the decreasing leaf δ13C in the wet year compared to the dry year. The river water contribution to the transpiration of riparian S. babylonica was found to be negatively linearly correlated with the water table depth and leaf δ13C (p<0.01). The rising groundwater level may increase the water extraction from the groundwater and/or river and produce a consumptive river-water-use pattern of riparian trees, which can have an adverse impact on the conservation of both river flow and riparian vegetation. This study provides new insights into understanding the mechanisms of the water cycle in a groundwater–soil–plant–atmosphere continuum and managing water resources and riparian afforestation along losing rivers. [ABSTRACT FROM AUTHOR]

Phthalates are environmental endocrine disruptors that enter the human body through a variety of pathways and harm human health. The study aimed to explore the associations between phthalate concentrations in glass window films with dormitory characteristics, occupancy activities and habits, and environmental factors, of university dormitories. We surveyed these associations and measured the indoor environmental parameters of 144 dormitories from 13 universities in Beijing. Based on the results, we further explored the factors affecting phthalate concentrations using multivariate logistic regression. The results showed that phthalate concentrations in glass window films were associated with dormitory type, duration of occupancy, daily ventilation duration, window cleaning frequency, indoor relative humidity, light intensity, temperature, and particulate matter (PM10) concentration. To date, there have only been a few studies on the factors that influence phthalate concentrations in glass window films; therefore, further study is needed. Our findings determined the influence of external factors on the different types of phthalates in window films, which helps understand indoor phthalate pollution and evaluate human exposure based on phthalate concentrations in glass window films. [ABSTRACT FROM AUTHOR]

The phthalate concentrations in dust from undergraduate dormitories, classrooms, and homes in Beijing, China, were measured in April 2017. We analyzed the characteristics of phthalates in dust from three environments. In addition, we estimated the daily intake of phthalates via three pathways using Monte Carlo simulations. The detection frequency of eight phthalates in dust ranges from 74.5 to 100%. Di (2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), and di-isobutyl phthalate (DiBP) are the most abundant phthalates. The median proportion of DEHP in dust is the highest, ranging from 67.1 to 72.9%. The PMF results indicated that two, four, and three types of phthalate sources exist in home, dormitory, and classroom, respectively. The differences in the phthalate concentrations between sunny and shaded rooms and urban and suburban classrooms are insignificant, whereas that between male and female dormitories is significant. The total daily intake of DEHP, DnBP, and DiBP ranges from 97.3 to 336 ng/ (kg·day). The oral intake for DEHP in classrooms and the dermal intake of DnBP and DiBP in homes are the highest. The carcinogenic risk of DEHP to university students is the highest in classrooms and the total carcinogenic risk of the three environments is 4.70 × 10-6. [ABSTRACT FROM AUTHOR]

[Display omitted] • DEHP, DCHP, and DnBP were the predominant phthalates in dormitory dust. • More attention should be paid to uncommon phthalates in dust, such as DCHP, DMEP, and DEEP. • More potential phthalate sources were found in female dormitories than male dormitories. • Increasing the daily ventilation duration can decrease phthalate exposure. • High PM 10 concentrations are associated with low phthalate concentrations in dormitory dust, possibly because of microplastics. Phthalates are used extensively as plasticizers in everyday materials and pose serious health hazards to humans. This study aimed to investigate the prevalence of dust-phase phthalates in university dormitories and their associations with dormitory characteristics, occupancy activities and habits, as well as environmental factors. We analyzed phthalate concentration levels in 142 dust samples collected from 13 university dormitories in Beijing and revealed the presence of ten phthalates with detection frequencies ranging from 82.4% to 100%. Among them, di (2-ethylhexyl) phthalate (DEHP), dicyclohexyl phthalate (DCHP), and di-n-butyl phthalate (DnBP) were the dominant phthalates in dormitory dust with median contribution values of 32.1%, 30.7%, and 12.4%, respectively. Multivariate logistic regression revealed a significant association between dormitory type, daily ventilation duration, indoor relative humidity, indoor temperature, and particulate matter (PM 10) concentrations and phthalate concentrations in dormitory dust. Moreover, the principal component analysis (PCA) indicated that there were three and two sources of phthalates in the male and female dormitories, respectively. This study comprehensively investigated the concentration levels of phthalates in dust from university dormitories in Beijing. Our results can aid in the comprehension and reduction of phthalate exposure among university students. [ABSTRACT FROM AUTHOR]

This study measured concentrations of fifteen phthalates in dust from homes (n = 19), offices (n = 10), kindergartens (n = 5) and public places (n = 7) in Beijing, China, during April 2010 and May 2011. We examined phthalate co-occurrence in dust collected from different indoor surfaces and estimated daily exposure to phthalates via dust ingestion, inhalation, and dermal absorption. Diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP) and di (2-Ethylhexyl) phthalate (DEHP) were the most abundant phthalates in each of the investigated environments (medians: 58.1–272 μg/g, 31.2–145 μg/g, and 202–1310 μg/g, respectively), with detection frequencies greater than 90% except for DiBP in dust from homes. Diethyl phthalate (DEP) was detected only in homes, with a detection frequency of 42%. The detection frequency of dinonyl phthalate (DNP) was 80% in public places (median: 78.8 μg/g). DnBP, DiBP and DEHP concentrations in different indoor environments differed significantly ( p < 0.05). Our findings suggest that DnBP, DiBP and DEHP originate from the same sources, while DNP has several sources. DEHP exposure is the highest for infants, children and adults. The exposure doses of DnBP and DEHP decrease as age increases. Dermal absorption from air is the main pathway for DiBP and DnBP, contributing from 56.4% to 84.7% of the total exposure. Dust ingestion is the main pathway for DEHP, contributing from 85.6% to 96.6% of the total exposure. [ABSTRACT FROM AUTHOR]

• This study reports the seasonal variation of airborne phthalates and its exposure assessment in college students. • DMEP and DnBP are the most abundant phthalates in the dormitory and classroom. • Airborne phthalates were relatively higher in the male dormitory in winter. • Airborne phthalates seasonally varied and were evident in winter. • Daily intake in dormitories and classrooms is the highest in winter. Phthalates are widely used as plasticizers in various products. However, only few studies have focused on its pollution in university dormitories and classrooms. In this study, we measured the airborne concentrations of phthalates in the dormitories and classrooms of a university in Beijing, China. We analyzed the pollution characteristics and possible sources of phthalates, used Monte Carlo simulation to estimate phthalate intake via inhalation and dermal absorption through direct air-through-skin pathways, and explored the seasonal variations in airborne phthalate concentrations and exposure levels. Di (2-methoxyethyl) phthalate and di-n-butyl phthalate were predominantly observed in the classroom and dormitory. Three possible phthalate sources existed in the classroom and dormitory. The airborne concentrations of high-molecular-weight phthalates were significantly higher in winter than those during spring and autumn. The room's orientation weakly affected the indoor airborne phthalate concentrations. More surface sinks in female dormitories significantly affected the concentration of airborne phthalates, which is worthy of a comprehensive study. Low-molecular-weight phthalates in the dormitory significantly differed between urban and suburban areas. The influences of orientation, dormitory type, and geographic location on indoor phthalate concentrations are related to the seasons. The total daily intake of phthalates in dormitories was greater than that in classrooms. The daily intake of phthalates via dermal absorption was greater than that via inhalation, and was the highest during winter. [ABSTRACT FROM AUTHOR]

Explains that Beijing University in China underwent five stages in the process of personnel system reform. Open recruitment and employment of college teachers in and outside China; Provision of 95 positions in all 28 departments and institutes; Preparations for reform; Sharp criticism; In-depth debate; Cooling of the debate and plan formation; Approval and implementation of the plan.

Phthalate concentrations were measured in glass window films in 145 dormitories at 13 universities in Beijing, China, from May to December 2019. We analyzed phthalate characteristics, examined possible phthalate sources, compared concentration differences between female and male dormitories and between sunny and shaded dormitories, and estimated the phthalate intake via dust ingestion, inhalation, and dermal absorption through direct air-through-skin pathways using Monte Carlo simulations. DCHP and DEHP were the most predominant phthalates in the window films, followed by DnBP, with median concentrations one to two orders of magnitude higher than those of the other phthalates. The contributions of DnBP, DCHP and DEHP to the total phthalate concentration were in the range of 2.2–45.9%. Phthalates in window films might have four indoor sources. The concentrations of six phthalates and ΣPAEs were higher in female dormitories than in male dormitories. Most phthalates showed no significant difference between sunny and shaded dormitories because the effects of temperature and photodegradation may have negated one another. The median phthalate intake ranged from 0.54 ng/(kg·day) to 4.61 μg/(kg·day). DMP and DEP exposures were the highest, followed by those of DiBP and DnBP. The intakes of 11 phthalates were higher for female students. Dermal absorption was the main exposure pathway of DMP, DEP, DiBP, DnBP, DMEP, DPP, DHP, and BBzP (contribution: 48.7–72.9%). For the other phthalates, dust ingestion was the main pathway (contribution: 64.5–97.5%). • This is the first study on phthalates in the window films of university dormitories. • DCHP, DEHP and DnBP are the most predominant phthalates in the window films. • Phthalates in the window films might have four types of sources. • Phthalate concentrations are higher in female than in male dormitories. [ABSTRACT FROM AUTHOR]

Phthalates are widely used as plasticizers in consumer products and are ubiquitous in indoor environments. Undergraduates spend a high amount of time indoors, however, little is known on the pollution characteristics and exposure to phthalates in indoor air in a university setting. In this study, passive air samplers measured the concentrations of phthalates in air from dormitories, classrooms, computer rooms, laboratories, and offices of a university in Beijing, China. A Monte-Carlo simulation was used to estimate the undergraduates' exposure via inhalation based on air concentrations. Six phthalates were detected, including Dimethyl phthalate(DMP), Di (isobutyl) phthalate(DiBP), Di (n-butyl) phthalate(DnBP), Di (2-Methoxyethyl) phthalate(DMEP), Di (2-n-Butoxyethyl) phthalate(DBEP), and Di (2-ethylhexyl) phthalate(DEHP). Sampling rates of polyurethane foam (PUF) were obtained from a calibration study by co-deploying passive and active air samplers in offices and laboratories, and the average sampling rate was 0.62 ± 0.33 m3/day. DnBP and DMEP were the most abundant phthalates in total investigated environments at the university. DMP, DnBP, and DMEP air concentrations showed significant differences in different indoor environments (p < 0.05). All phthalate concentrations were not significantly different between the sunny sides and shadowy sides of rooms (p > 0.05). DMP concentrations were significantly different between male and female dormitories (p < 0.05). Correlation analysis suggests that DiBP, DnBP, and DMEP may originate from the same sources, while DBEP and DEHP may originate from a separate common source. The daily intake of phthalates via inhalation in dormitories is greater than in classrooms, except for DMP, which may lead to higher carcinogenic risks for undergraduates. • Both the passive and active method were firstly adopted to study airborne phthalates in university campuses of China. • Passive sampling rate of PUF for phthalates was 0.13–1.39 m3/day. • DnBP and DMEP were the most abundant. Phthalate concentrations had no difference between orientations of room. • Inhalation exposure of phthalates in dormitories was in the range of 3.6–237.1 ng / (kg ⋅ d). • The carcinogenic risk of DEHP in dormitories and classrooms was 1.72 times higher than EPA limit value. [ABSTRACT FROM AUTHOR]

This study measured concentrations of seven phthalates in gas-phase, particle-phase and dust/soil in kindergarten indoors and outdoors in Beijing, China, during May to July 2012. We analysed phthalate pollution characteristics, examined phthalate co-occurrence and estimated intake of phthalates via dust ingestion, inhalation, and dermal absorption through direct air-through-skin using Monte Carlo simulation. Phthalate pollution level indoors were higher than outdoors. Di (2-Ethylhexyl) phthalate (DEHP), Diisobutyl phthalate (DiBP) and Di-n-butyl phthalate (DnBP) was the most abundant phthalate in dust, gas-phase and particle-phase indoors, respectively, with an average contribution of 48.4%, 41.0% and 41.1%. DEHP was the most predominant phthalate in outdoor sampled medias, and the average contribution was in the range of 45.5%–48.6%. Indoor phthalate concentration in dust is not related to the sampled surface and grade, and is related to the sampled kindergartens. The co-occurrence of phthalates is related to the type of phthalates and sampling medias. The pollution level of DiBP and DnBP in dust and airborne is more serious in kindergarten in China, which should be paid more attention. Total intake of DiBP is the most in kindergarten. Outdoor phthalate exposure is much lower than indoor, only contributing from 2.68% to 7.07% to total intake. Dermal absorption is the main exposure pathway for indoor exposure of DiBP and DnBP, contributing 57.8% and 60.3%, while dust ingestion is the main exposure pathway for indoor exposure of DEHP, contributing 74.4%. We should take some control approaches to decrease the phthalate exposure for pre-children. • Indoor and outdoor exposure to phthalates for pre-school children was first studied in kindergarten in China. • DEHP, DiBP and DnBP was the most abundant phthalate in dust, gas-phase and particle-phase indoors, respectively, with an average contribution of 48.4%, 41.0% and 41.1%. DEHP was the most predominant phthalate in outdoor sampled medias, and the average contribution was in the range of 45.5%-48.6%. • The pollution level of DiBP and DnBP in dust and airborne is more serious in kindergarten in China. • Phthalate pollution level indoors were higher than outdoors; moreover, outdoor phthalate exposure is much lower than indoor, only contributing from 2.68% to 7.07% to total intake. • Total intake of DiBP is the highest. Dermal absorption is the main exposure pathway for DiBP and DnBP, contributing 57.8% and 60.3%; while dust ingestion is the main exposure pathway for DEHP, contributing 74.4%. [ABSTRACT FROM AUTHOR]

• Water use of riparian trees under various water table depth (WTD) along a losing river was determined. • Riparian trees accessed more upper soil water and had lower leaf δ13C under deep WTD compared to shallow WTD. • Water source contribution was a parabolic function of WTD and 2.1 m was the optimum WTD to utilize deep water. • Leaf δ13C had a positive linear relation with proportional contribution of deep water. Rivers losing flow into surrounding aquifers ('losing' rivers) are common under changing climates and groundwater overexploitation. The riparian plant-water relations under various water table dynamics along a losing river remain unclear. In this study, the water isotopes (δ2H and δ18O), leaf δ13C, and MixSIAR model were used combinedly for determining the root water uptake patterns and leaf water use efficiency (WUE) of Salix babylonica (L.) at three sites (A, B, and C) with different water table depths (WTDs) in the riparian zone of Jian and Chaobai River in Beijing, China. The correlations of water source contributions with WTD and WUE were quantified. The riparian S. babylonica primarily took up upper (0–80 cm) soil water (71.5%) with the lowest leaf δ13C (−28.8 ± 1.1 ‰) at site A under deep WTD (20.5 ± 0.5 m). In contrast, deep water below 80 cm depth including groundwater contributed 55.1% to S. babylonica at site B with fluctuated shallow WTD (1.9 ± 0.4 m), where leaf δ13C was highest (−27.9 ± 1.0 ‰). The S. babylonica mainly used soil water in 30–170 cm layer (56.9%) with mean leaf δ13C of − 28.2 ‰ ± 0.7 ‰ at site C with stable shallow WTD (1.5 ± 0.1 m). It was found that both the contributions of upper soil water in 0–80 cm and deep water below 80 cm had significantly quadratic correlations with WTD under shallow water table conditions (p < 0.05). Leaf δ13C was negatively correlated with contributions of upper soil water above 80 cm depth, but it was positively related to the contributions of deep water below 80 cm in linear functions (p < 0.001). The results indicated that 2.1 m was the optimum WTD for riparian trees, because they maximized the use of deep water sources to get the highest WUE. This study provides insights into managing groundwater, surface water resources and riparian afforestation in losing rivers. [ABSTRACT FROM AUTHOR]

• Potential water source line (PWL) was proposed to correct δ2H offset of stem water. • PWL was assessed using riparian trees at three sites with different water tables. • Water source identifications were compared among seven types of input isotope data. • Dual isotopes with PWL-corrected δ2H obtained higher groundwater contribution. Root water uptake plays an important role in water cycle in Groundwater-Soil-Plant-Atmosphere-Continuum. Stable isotopes (δ2H and δ18O) are effective tools to quantify the use of different water sources by plant roots. However, the widespread δ2H offsets of stem water from its potential sources due to δ2H fractionation during root water uptake result in conflicting interpretations of water utilization using stable isotopes. In this study, a potential water source line (PWL), i.e., a linear regression line between δ18O and δ2H data of both soil water at different depths and groundwater, was proposed to correct δ2H offsets of stem water. The PWL-corrected δ2H was determined by subtracting the deviation between δ2H in stem water and PWL from the original value. The MixSIAR model coupled with seven types of input data (i.e. various combinations of single or dual isotopes with uncorrected or corrected δ2H data by PWL or soil water line (SWL)) were used to determine seasonal variations in water uptake patterns of riparian tree of Salix babylonica (L.) along the Jian and Chaobai River in Beijing, China. These methods were evaluated via three criteria including Akaike Information Criterion (AIC), Bayesian Information Criterion (BIC) and root mean square error (RMSE). Results showed that different types of input data led to considerable differences in the contributions of soil water at upper 30 cm (9.9–57.6%) and below 80 cm depths (29.0–76.4%). Seasonal water uptake patterns were significantly different especially when δ2H offset was pronounced (p < 0.05). The dual-isotopes method with uncorrected δ2H underestimated the contributions of soil water in the 0–30 cm layer (by 30.4%) and groundwater (by 56.3%) compared to that with PWL-corrected δ2H. The PWL correction method obtained a higher groundwater contribution (mean of 29.5%) than that estimated by the SWL correction method (mean of 24.5%). The MixSIAR model using dual-isotopes with PWL-corrected δ2H produced the smallest AIC (94.1), BIC (91.9) and RMSE values (4.8%) than other methods (94.9–101.7, 92.6–99.5 and 5.3–12.4%, respectively), which underlined the best performance of PWL correction method. The present study provides crucial insights into quantifying accurate root water uptake sources even if δ2H offset exists. [ABSTRACT FROM AUTHOR]