Inhibitory effects of phthalate esters (PAEs) and phthalate monoesters towards human carboxylesterases (CESs).

Phthalate esters (PAEs), accompanied by phthalate monoesters as hydrolysis metabolites in humans, have been widely used as plasticizers and exhibited disruptive effects on the endocrine and metabolic systems. The present study aims to investigate the inhibition behavior of PAEs and phthalate monoesters on the activity of the important hydrolytic enzymes, carboxylesterases (CESs), to elucidate the toxicity mechanism from a new perspective. The results showed significant inhibition on CES1 and CES2 by most PAEs, but not by phthalate monoesters, above which the activity of CES1 was strongly inhibited by DCHP, DEHP, DiOP, DiPP, DNP, DPP and BBZP, with inhibition ratios exceeding 80%. Kinetic analyses and in vitro-in vivo extrapolation were conducted, revealing that PAEs have the potential to disrupt the metabolism of endogenous substances catalyzed by CES1 in vivo. Molecular docking results revealed that hydrogen bonds and hydrophobic contacts formed by ester bonds contributed to the interaction of PAEs towards CES1. These findings will be beneficial for understanding the adverse effect of PAEs and phthalate monoesters.

Characterization of Biodiesel and Diesel Combustion Particles: Chemical Composition, Lipid Metabolism, and Implications for Health and Environment.

Biodiesel, derived from alkyl esters of vegetable oils or animal fats, has gained prominence as a greener alternative to diesel due to its reduced particle mass. However, it remains debatable whether biodiesel exposure has more severe health issues than diesel. This study performed high-resolution mass spectrometry to examine the detailed particle chemical compositions and lipidomics analysis of human lung epithelial cells treated with emissions from biodiesel and diesel fuels. Results show the presence of the peak substances of CHO compounds in biodiesel combustion that contain a phthalate ester (PAEs) structure (e.g., n-amyl isoamyl phthalate and diisobutyl phthalate). PAEs have emerged as persistent organic pollutants across various environmental media and are known to possess endocrine-disrupting properties in the environment. We further observed that biodiesel prevents triglyceride storage compared to diesel and inhibits triglycerides from becoming phospholipids, particularly with increased phosphatidylglycerols (PGs) and phosphatidylethanolamines (PEs), which potentially could lead to a higher probability of cancer metastasis.

Phthalate esters delivery to the largest European lagoon: Sources, partitioning and seasonal variations.

Phthalate esters (PAEs) due to their ability to leach from plastics, widely used in our daily life, are intensely accumulating in wastewater water treatment plants (WWTP) and rivers, before being exported to downstream situated estuarine systems. This study aimed to investigate the external sources of eight plasticizers to the largest European lagoon (the Curonian Lagoon, south-east Baltic Sea), focusing on their seasonal variation and transport behaviour through the partitioning between dissolved and particulate phases. The obtained results were later combined with hydrological inputs at the inlet and outlet of the lagoon to estimate system role in regulating the transport of pollutants to the sea. Plasticizers were detected during all sampling events with a total concentration ranging from 0.01 to 6.17 µg L-1. Di(2-ethylhexyl) phthalate (DEHP) was the most abundant PAEs and was mainly found attached to particulate matter, highlighting the importance of this matrix in the transport of such contaminant. Dibutyl phthalate (DnBP) and diisobutyl phthalate (DiBP) were the other two dominant PAEs found in the area, mainly detected in dissolved phase. Meteorological conditions appeared to be an important factor regulating the distribution of PAEs in environment. During the river ice-covered season, PAEs concentration showed the highest value suggesting the importance of ice in the retention of PAEs. While heavy rainfall impacts the amount of water delivered to WWTP, there is an increase of PAEs concentration supporting the hypothesis of their transport via soil leaching and infiltration into wastewater networks. Rainfall could also be a direct source of PAEs to the lagoon resulting in net surplus export of PAEs to the Baltic Sea.

Human Endocrine-Disrupting Effects of Phthalate Esters through Adverse Outcome Pathways: A Comprehensive Mechanism Analysis.

Phthalate esters (PAEs) are widely exposed in the environment as plasticizers in plastics, and they have been found to cause significant environmental and health hazards, especially in terms of endocrine disruption in humans. In order to investigate the processes underlying the endocrine disruption effects of PAEs, three machine learning techniques were used in this study to build an adverse outcome pathway (AOP) for those effects on people. According to the results of the three machine learning techniques, the random forest and XGBoost models performed well in terms of prediction. Subsequently, sensitivity analysis was conducted to identify the initial events, key events, and key features influencing the endocrine disruption effects of PAEs on humans. Key features, such as Mol.Wt, Q+, QH+, ELUMO, minHCsats, MEDC-33, and EG, were found to be closely related to the molecular structure. Therefore, a 3D-QSAR model for PAEs was constructed, and, based on the three-dimensional potential energy surface information, it was discovered that the hydrophobic, steric, and electrostatic fields of PAEs significantly influence their endocrine disruption effects on humans. Lastly, an analysis of the contributions of amino acid residues and binding energy (BE) was performed, identifying and confirming that hydrogen bonding, hydrophobic interactions, and van der Waals forces are important factors affecting the AOP of PAEs' molecular endocrine disruption effects. This study defined and constructed a comprehensive AOP for the endocrine disruption effects of PAEs on humans and developed a method based on theoretical simulation to characterize the AOP, providing theoretical guidance for studying the mechanisms of toxicity caused by other pollutants.

Sorption behavior of dimethyl phthalate in biochar-soil composites: Implications for the transport of phthalate esters in long-term biochar amended soils.

The characteristics and content of organo-mineral complex were confirmed to be changed in agriculture soils under the biochar application with long-term, but the resulting environmental effects in the retention and lasting of agrochemicals and xenobiotic pollutants is far from clear. In this study, biochar-soil composites were prepared by one-step dry ball-milling method, and a sorption case study was proceed to investigate the biochar incorporated affection in soils on the transport of dimethyl phthalate (DMP). More surface oxygen-containing functional groups on ball-milled biochar enhanced its complexation with soil minerals. Sorption isotherms of DMP onto the biochar-soil composites were well described by the Freundlich model, both heterogeneous surface and multilayer interactions occurred simultaneously. The kinetics of sorption could be simulated with the pseudo-second-order model (R2 > 0.98), while the average sorption energy (Ea) calculated from Dubinin-Radushkevich isotherms were found in the range of 3.83-5.60 kJ mol-1, which revealed that the sorption processes coexist of chemisorption and physisorption, and π-π electron donor-acceptor interaction, pore-filling and hydrophobic interactions could be identified as the main sorption mechanisms. Desorption of absorbed DMP appeared obvious nonlinear characteristics and lag effect, the calculated hysteresis index (HI) increased with the application of biochar into soil. Considering the phenomenon of biochar aging and soil complexation, it is important to verify how the transport and natural attenuation of contaminant will be influenced by biochar addition, especially the long-term effect in soil ecosystem.

Exposure and ecological risk of phthalate esters in the Taihu Lake basin, China.

The environmental spatial distribution and exposure risk of 6 phthalate esters (PAEs) including dimethyl phthalate (DMP), diethyl phthalate (DEP), butyl benzyl phthalate (BBP), di-n-octyl phthalate (DnOP), bis(2-ethylhexyl) phthalate (DEHP), and dibutyl phthalate (DBP), in surface water and sediment of Taihu Lake basin, China, were investigated at 65 sites. The exposure concentrations of 6 PAEs (∑6PAEs) detected in the samples spanned a range of 0.740-13.0 µg/L in surface water and 5.15-20.9 mg/kg in sediment. DBP and DEHP were the predominant compounds in surface water, with mean concentrations of 1.59 µg/L and 1.29 µg/L, respectively. DnOP was the predominant compound in sediment with mean concentration of 7.41 mg/kg. Ecological risk assessment was conducted by the hazard quotient method in which the predicted no effect concentration (PNEC) was derived from the species sensitivity distribution (SSD) curve. The results showed that DEHP in water phase posed a higher environmental risk than the other PAEs, while the DEP in sediment posed a high risk to the aquatic system. The study contributed to better understanding the presence of PAEs in Taihu Lake basin and provided valuable information for managing and controlling PAEs pollution.

How do root exudates of bok choy promote dibutyl phthalate adsorption on mollisol?

This study investigates the interaction between the bok choy root exudates and dibutyl phthalate (DBP) onto mollisol during the adsorption. The result elucidated that the adsorption reached equilibrium within 12 h, the adsorption capacity of rhizosphere mollisol containing root exudates and ordinary mollisol were 243.46 mg kg-1 and 281.95 mg kg-1, separately. The adsorption kinetics and isotherm model followed the pseudo-second order and the Frendlish model, respectively, which hinted that the adsorption process was multi-layer heterogeneous chemisorption. We characterized the root exudates and analyzed its effects on soil physical and chemical properties and structure. The result revealed that the root exudates contained hydrocarbons, sulfur compounds and acids. Root exudates made the dissolved organic matter (DOM) dissolution from soil and the increase of organic matter, which might be one of the reasons that root exudates promote DBP adsorption on mollisol. We selected three-dimensional excitation-emission matrix (3D-EEM), synchronous fluorescence and Fourier transform infrared spectroscopy (FTIR) to analyze the interactions between root exudates and DBP, DOM and DBP, respectively. Fluorescence spectrum revealed that the main component of root exudates was protein, for DOM was humic acid, the fluorescence of root exudates and DOM gradually disappeared with the increase of DBP concentration. FTIR revealed that -COO in root exudates and -CH2 in DOM respectively reacted with DBP. The results of this study are of great importance to reveal that the root exudates are significant in the environmental behavior of DBP adsorption on mollisol, and also provide more useful information for phytoremediation of organic pollutants in the mollisol.

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.

Root-zone regulation and longitudinal translocation cause intervarietal differences for phthalates accumulation in vegetables.

Selecting and cultivating low-accumulating crop varieties (LACVs) is the most effective strategy for the safe utilization of di-(2-ethylhexyl) phthalate (DEHP)-contaminated soils, promoting cleaner agricultural production. However, the adsorption-absorption-translocation mechanisms of DEHP along the root-shoot axis remains a formidable challenge to be solved, especially for the research and application of LACV, which are rarely reported. Here, systematic analyses of the root surface ad/desorption, root apexes longitudinal allocation, uptake and translocation pathway of DEHP in LACV were investigated compared with those in a high-accumulating crop variety (HACV) in terms of the root-shoot axis. Results indicated that DEHP adsorption was enhanced in HACV by root properties, elemental composition and functional groups, but the desorption of DEHP was greater in LACV than HACV. The migration of DEHP across the root surface was controlled by the longitudinal partitioning process mediated by root tips, where more DEHP accumulated in the root cap and meristem of LACV due to greater cell proliferation. Furthermore, the longitudinal translocation of DEHP in LACV was reduced, as evidenced by an increased proportion of DEHP in the root apoplast. The symplastic uptake and xylem translocation of DEHP were suppressed more effectively in LACV than HACV, because DEHP translocation in LACV required more energy, binding sites and transpiration. These results revealed the multifaceted regulation of DEHP accumulation in different choysum (Brassica parachinensis L.) varieties and quantified the pivotal regulatory processes integral to LACV formation.

Migration and distribution characteristics of typical organic pollutants in condensable particulate matter of coal-fired flue gas and by-products of wet flue gas desulfurization system.

The wet flue gas desulfurization (WFGD) system of coal-fired power plants shows a good removal effect on condensable particulate matter (CPM), reducing the dust removal pressure for the downstream flue gas purification devices. In this work, the removal effect of a WFGD system on CPM and its organic pollutants from a coal-fired power plant was studied. By analyzing the organic components of the by-products emitted from the desulfurization tower, the migration characteristics of organic pollutants in gas, liquid, and solid phases, as well as the impact of desulfurization towers on organic pollutants in CPM, were discussed. Results show that more CPM in the flue gas was generated by coal-fired units at ultra-low load, and the WFGD system had a removal efficiency nearly 8% higher than that at full load. The WFGD system had significant removal effect on two typical esters, especially phthalate esters (PAEs), with the highest removal efficiency of 49.56%. In addition, the WFGD system was better at removing these two esters when the unit was operating at full load. However, it had a negative effect on n-alkanes, which increased the concentration of n-alkanes by 8.91 to 19.72%. Furthermore, it is concluded that the concentration distribution of the same type of organic pollutants in desulfurization wastewater was similar to that in desulfurization slurry, but quite different from that in coal-fired flue gas. The exchange of three organic pollutants between flue gas and desulfurization slurry was not significant, while the concentration distribution of organic matters in gypsum was affected by coal-fired flue gas.

Advanced oxidation processes for the removal of phthalate esters (PAEs) in aqueous matrices: a review.

Over the past few decades, phthalate esters (PAEs) used as additives to improve the persistence and flexibility of polymeric materials. They are also used in cosmetics, insect repellents, and propellants, and their continuous input into drinking waters has constituted a serious risk to human health and the environment. DBPs are compounds classified as hazardous substances and have teratogenic properties. Due to the high bioaccumulation of DBP, they have toxic properties in different organisms, making it very important to remove PAEs before discharging them into environments. In this study a systematic review was designed to evaluate Advanced oxidation processes (AOPs) studies which have successfully treated contaminated water with PAEs. Among AOPs, particularly photocatalytic, UV/H2O2 photolysis, sonolysis, and ozone-based processes were more tried to degrade PAEs in aqueous solutions. Additionally, a more detail of each AOPs was explained. Findings showed that all advanced oxidation processes, especially combined AOPs have good results in the degradation of PAEs in water.

Phthalate esters in the Largest River of Asia: An exploration as indicators of microplastics.

Phthalate esters (PAEs) are the most ubiquitous and highly used plasticizers in plastic products globally, yet studies on the spatial variation, risks, and their correlation with microplastics (MPs) are limited, particularly throughout the Yangtze River (the largest river in China/Asia). Therefore, this study investigated for the first time the PAEs pollution characteristics throughout the Yangtze River sediments, studied the environmental factors linked to the distribution of PAEs, and explored their potential as chemical indicators for interpreting pollution patterns of MPs. Totally 14 out of 16 PAEs were detected in sediments, with total concentrations ranging from 84.67 ng/g to 274.0 ng/g (mean: 163.5 ng/g), dominated by Bis(2-ethylhexyl) phthalate (DEHP), Di-n-butyl phthalate (DBP), and Di-isobutyl phthalate (DIBP), with contributions of 38.9 %, 31.8 %, and 20.8 %, respectively. Spatial distribution of PAEs did not indicate significant differences, which may be related to anthropogenic activities (i.e., emission intensity), runoff, and sediment physicochemical properties (i.e., TOC and TN), with TOC and TN being potential predictors of PAEs. The quantitative relationships (p < 0.001) between DEHP/∑16PAEs ratio and MPs (both individual and total MPs) were found in sediments, which suggested that DEHP could be potentially used as an indicator for MPs. DEHP, DIBP, and DBP posed high risks, accounting for 100 %, 68.4 %, and 10.5 % of the monitoring sites, respectively. Further work is necessary to better understand the relationship between DEHP/∑16PAEs and MPs in the environment and to take corresponding management and control measures for these pollutants.

Assessing human exposure to phthalate esters in drinking water migrated from various pipe materials and water filter elements during water treatments and storage.

Plastic water-supply pipes and filter element are frequently used in municipal water supply systems. Leaching of phthalate esters (PAEs) from these pipes and filter elements to drinking water has become a common concern among the public. In this study, the migrations of 16 phthalate esters (PAEs) in seven different kinds of water-supply product materials were investigated. Di-n-butyl phthalate (DBP) had the highest detection frequency of 54.4% in the water leaching samples of various water supply pipes and water filter elements samples, followed by Diisobutyl phthalate (DIBP, 46/90, 51.1%). The maximum detected concentration level for di(2-ethylhexyl) phthalate (DEHP), diethyl phthalate (DEP), and DBP in the leaching experiment was below the regulatory limit values of 8 µg/L, 300 µg/L, and 3 µg/L for each compound in China standards for drinking water quality. The increasing of the water temperature, the lower pH of the water, and the increasing of the leaching time will increase the migration of PAEs from plastic pipes into water. The chronic daily intake of children aged < 1-12 years to PAEs through drinking water was higher than the rest of the population groups. Carcinogenic risks (CR) of DEHP via drinking water were neglectable for most groups of people, while for young children with age of 1-2 years old, the CR is an acceptable risk.

Composition, distribution, health risks, and drivers of phthalates in typical red paddy soils.

The accelerated accumulation of phthalate esters (PAEs) in paddy soils poses a serious threat to human health. However, related studies mainly focus on facility vegetable fields, drylands, and orchards, and little is known about paddy soils. In this study, 125 samples were collected from typical red paddy fields to investigate the pollution characteristics, sources, health risks, and main drivers of PAEs. Soil physicochemical properties, enzyme activity, and bacterial community composition were also measured simultaneously. The results showed that eight PAE congeners were detected ranging from 0.17 to 1.97 mg kg-1. Di-n-butyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP), and di-isobutyl phthalate (DIBP) were the most abundant PAE congeners, accounting for 81% of the total PAEs. DEHP exhibited a potential carcinogenic risk to humans through the intake route. The main PAEs were positively correlated with soil organic matter (SOM) and soil water content (SWC) contents. Low levels of PAEs increased bacterial abundance. Furthermore, most PAE congeners were positively correlated with hydrolase activity. Soil acidity and nutrient dynamics played a dominant role in the bacterial community composition, with PAE congeners playing a secondary role. These findings suggest that there may be a threshold response between PAEs and organic matter and nutrient transformation in red paddy soils, and that microbial community should be the key driver. Overall, this study deepens the understanding of ecological risks and microbial mechanisms of PAEs in red paddy soils.

Inhibition of Human Sulfotransferases by Phthalate Monoesters.

Objective: This study aimed to investigate the inhibition of human important phase II metabolic enzyme sulfotransferases (SULTs) by phthalate monoesters, which are important metabolites of phthalate esters (PAEs). Method: Recombinant SULT-catalyzed metabolism of p-nitrophenol (PNP) was employed as the probe reactions of SULTs to investigate the inhibition of 8 kinds of phthalate monoesters towards SULT isoforms. An in vitro incubation system was utilized for preliminary screening, and 100 µM of phthalate monoesters was used. Inhibition kinetics were carried out to determine the inhibition of SULTs by phthalate monoesters. Result: Multiple phthalate monoesters have been demonstrated to exert strong inhibition potential towards SULT1A1, SULT1B1, and SULT1E1, and no significant inhibition of phthalate monoesters towards SULT1A3 was found. The activity of SULT1A1 was strongly inhibited by mono-hexyl phthalate (MHP), mono-octyl phthalate (MOP), mono-benzyl phthalate (MBZP), and mono-ethylhexyl phthalate (MEHP). Monobutyl phthalate (MBP), MHP, MOP, mono-cyclohexyl phthalate (MCHP), and MEHP significantly inhibited the activity of SULT1B1. MHP, MOP, and MEHP significantly inhibited the activity of SULT1E1. MOP was chosen as the representative phthalate monoester to determine the inhibition kinetic parameters (Ki) towards SULT1B1 and SULT1E1. The inhibition kinetic parameters (Ki) were calculated to be 2.23 µM for MOP-SULT1B1 and 5.54 µM for MOP-SULT1E1. In silico docking method was utilized to understand the inhibition mechanism of SULT1B1 by phthalate monoesters. Conclusions: All these information will be beneficial for understanding the risk of phthalate monoester exposure from a new perspective.

The effects of salinity, temperature, and UV irradiation on leaching and adsorption of phthalate esters from polyethylene in seawater.

In this study, the leaching of six phthalic acid esters (PAEs) from three common consumer plastics was investigated: low and high density polyethylene (LDPE, HDPE) and recycled polyethylene (RP). The effects of salinity, temperature, and ultraviolet irradiation (UVR) on leaching were investigated. The study of leaching of phthalates in aqueous environments in batch experiments is challenging due to their readsorption by the high hydrophobicity of PAEs, and there are no standard methods to study release processes. Here with the experiments, leaching (A) and spiking (B) using six PAEs to study the readsorption in the leaching process. PAEs were identified and quantified using GC-MS. Dibutyl phthalate (DBP) and benzyl butyl phthalate (DEHP) showed considerable leaching during the 5-day incubation: 14 ±â€¯1 to 128 ±â€¯14 and 25 ±â€¯2 to 79 ±â€¯5 ng/cm2, respectively, under UVR, corresponding approximately to (1.9-13%) and (12.4-22.4%) of the solvent extracted mass. The highest Kd values were measured for RP polymers (0.3-9.4), followed by LDPE (0.5-5.4) and HDPE (0.2-2.2) polymers. Thus, readsorption of PAEs at the surface removed 30-80% of the leached PAEs in the dissolved phase. For example in LDPE, the calculated total release of DBP was up to 54 ±â€¯4 ng/cm2, while the dissolved amount was 8.5 ±â€¯1 ng/cm2 during the 5-day incubation under freshwater conditions. Increasing salinity negatively affected the leaching rate, which decreased for DBP from 54 ±â€¯4 ng/cm2 in freshwater to 44 ±â€¯3 and 38 ±â€¯3 ng/cm2 at salinity of 20 and 40 g/L, respectively, from LDPE during the 5-day incubation. Temperature and UVR had a positive effect on the leaching rate, with the release of DBP from LDPE increasing from 44 ±â€¯3 ng/cm2 at room temperature (25 °C) to 60 ±â€¯6 and 128 ±â€¯14 ng/cm2 at high temperature (40 °C) and UVR, respectively. Overall, this study highlights the positive relationship between temperatures, UVR on the extent of leaching and surface adsorption on the leaching measurements.

The effect of heavy rainfall on the exposure risks of sedimentary phthalate esters to aquatic organisms.

Phthalate esters (PAEs) have known widely being used in plastic products leading to being ubiquitous in the environment by easy to release from those products. This study aims to understand the impact of heavy rainfall on the concentration of PAEs in surface sediments of the Salt River in Kaohsiung, Taiwan, and its potential ecological risks on aquatic organisms. The potential ecological risk assessment of sediment PAEs is based on the total risk quotient (TRQ) method. The total concentration of 10 PAEs (∑PAE10) in sediments of the Salt River is 333-13,615 ng/g dw, with an average of 4212 ± 3753 ng/g dw. Before the rainy season, the ∑PAE10 concentration in sediments at the outlets of domestic sewage in upstream was 9768-13,615 ng/g dw, which were relatively higher than other sites (542-3721 ng/g dw). During the rainy season, the ∑PAE10 concentration was 2820-12,041 ng/g dw, which was 1-11 times higher than that determined before the rainy season. After the rainy season, the ∑PAE10 concentration recorded was 530-6652 ng/g dw, which is 1-11 times lower than the value obtained during the rainy season. PAEs in sediments of the Salt River may have low to moderate potential risks to algae, crustaceans, and fish. Bis(2-ethylhexyl) phthalate (DEHP) and diisobutyl phthalate (DiBP) are the main PAE that poses a potential risk to algae and crustaceans, and to fish respectively, whose values of risk quotient accounts for 40-69% of the TRQ value. The distribution of TRQ values for these aquatic organisms show a decreasing trend of PAEs level with respect to the rainy season: during the rainy season > after the rainy season > before the rainy season. Heavy rainfall may cause more serious pollution in sediments and increase the exposure risk of PAEs to aquatic organisms.

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.

Bacterial community progression during food waste composting containing high dioctyl terephthalate (DOTP) concentration.

The overall dioctyl terephthalate (DOTP) degradation efficiency during food waste composting was 98%. The thermophilic phases contributed to 76% of the overall degradation efficiency, followed by the maturation phase (22%), then the mesophilic phase (0.7%). The thermophilic phase had the highest specific degradation rate of 0.149 d-1. The progression of the bacterial community during the composting process was investigated to understand DOTP biodegradation. The results showed that the bacterial richness and the alpha diversity of the DOTP composting were similar to a typical composting process, indicating that the high concentration of DOTP did not hinder the thriving and evolution of the bacterial community. Additionally, Firmicutes was the most dominant at the phylum level, followed by Proteobacteria and Bacteroidetes. Bacilli was the most dominant class (70%) in the mesophilic phase, with the abundance decreasing thereafter in the thermophilic and maturation phase. Moreover, Lactobacillus sp. was the dominant species at the beginning of the experiment, which was probably responsible for DOTP biodegradation. The high removal efficiency observed in the maturation phase indicates that degradation occurs in all the composting phases, and that compost can be used to enhance natural attenuation. These findings provide a better understanding of the bacterial communities during biodegradation of DOTP and plasticizers via food waste composting and should facilitate the development of appropriate green bioremediation technologies.

[Distribution Characteristics and Ecological Risk Assessment of Phthalate Esters in Surface Sediments of the Songhua River].

This study assesses the spatial distribution characteristics and ecological risk of phthalate esters (PAEs) in the surface sediments of the mainstream and tributaries of the Songhua River, China, using concentrations and composition of six PAEs, which were analyzed using gas chromatography-mass spectrometery (GC-MS). We assess the ∑6PAEs ecological risk using the hazard quotient (HQ) method and environmental risk levels (ERL). The results were as follows. ① It was found that the total concentrations of ∑6PAEs ranged from 6832.5 to 36298.9 ng·g-1 dry weight (average 18388.6 ng·g-1), with the main contributions coming from di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP). The difference between the main stream ∑6PAEs (6832.5-36298.9 ng·g-1, average 18616.9 ng·g-1) and the tributary ∑6PAEs (10367.6-26593.3 ng·g-1, average 18264.1 ng·g-1) was not significant (P >0.05). The mean concentrations of individual PAEs in the tributary stream differed little from that of the main stream. The ∑6PAEs concentration of the Songhua River decreased initially but then increased from the upstream to the downstream. The average ∑6PAEs concentration in natural agricultural areas (18677.5 ng·g-1) was similar to that found in urban industrial areas (18063.7 ng·g-1), and DBP and DEHP contributed 98% of ∑6PAEs. ② The main sources of ∑6PAEs were domestic, agricultural production, and industrial production using plasticizers. ③ The ecological risk assessment indicated that DMP and BBP in the surface sediments of the Songhua River did not pose an ecological risk for aquatic organisms, and that DEP was associated with a low ecological risk, whereas DEHP and DBP posed a high ecological risk for aquatic organisms.