Soil contamination and sources of phthalates and its health risk in China: A review

Accumulation characteristics and fate modeling of phthalic acid esters in surface water from the Three Gorges Reservoir area, China

Phthalic acid esters (PAEs) are a group of compounds widespread in the environment. To investigate the occurrence and accumulation characteristics of PAEs, surface water samples were collected from the Three Gorges Reservoir area, China. The total concentrations of 11 analyzed PAEs (∑11PAEs) in the collected water samples ranging from 197.7 to 1,409.3 ng/L (mean ± IQR: 583.1 ± 308.4 ng/L). While DEHP was the most frequently detected PAE, DnBP and DnNP were the most predominant PAEs in the analyzed water samples with a mean contribution of 63.3% of the ∑11PAEs. The concentrations of the ∑11PAEs in the water samples from the upper reaches of the Yangtze River were significantly higher than those from the middle reaches. To better understand the transport and fate of the PAEs, seven detected PAEs were modeled by Quantitative Water Air Sediment Interaction (QWASI). The simulated and measured values were close for most PAEs, and differences are within one order of magnitude even for the worst one. For all simulated PAEs, water and particle inflow were main sources in the reservoir, whereas water outflow and degradation in water were important removal pathways. The contribution ratios of different sources/losses varied from PAEs, depending on their properties. The calculated risk quotients of DnNP in the Three Gorges Reservoir area whether based on monitoring or simulating results were all far exceeded the safety threshold value, implying the occurrence of this PAE compound may cause potential adverse effects for the aquatic ecology of the Three Gorges Reservoir area.

Occurrence, migration and health risks of fluorescent whitening agents and phthalates in bottled water

The occurrence and health risks of fluorescent whitening agents (FWAs) in bottled water were reported for the first time. FWA184 and FWA393 were the most frequently detected FWAs, with mean concentrations of 3.99-17.00 ng L-1. Phthalates (PAEs) such as dibutyl phthalate (DBP), di-iso-butyl phthalate (DiBP), and diethylhexyl phthalate (DEHP) were prevalent in bottled water, with mean levels of 40.89-716.66 ng L-1, and their concentrations in bottled water were much higher than those of FWAs. FWAs and PAEs in bottles and caps were extracted using organic solvent, and the correlation analysis showed that FWA393 and DEHP most likely originated from bottles, while bottle caps were the main sources of DBP and DiBP. The calculated risk quotients (RQs) of target substances and all age groups were considerably lower than the threshold of 0.1, indicating that consuming bottled water containing these plastic additives was unlikely to pose health risks for people of all ages. However, RQ values for underage people were several times higher than those for adults and hence cannot be neglected; therefore, special attention should be paid to understand the potential risks posed by the exposure to these plastic additives during early life stages, especially the infant stage.

Phthalates and other organic chemicals in agricultural soils after use of different types of conventional and biodegradable plastics

Various plastic materials are used in contact with agricultural soil, like mulching films, crop covers, weed controlling fabrics and nets. Polyethylene (PE) mulches have already been recognized as a significant source of plastic in soil and they have been shown to contain additives like phthalates, known as endocrine disruptors. However, other agricultural plastics are less studied, and little is known on the substances potentially released from them endangering biodiversity and the human health. This research aims to assess whether different agricultural plastics release additives into soil and to compare the release among various materials. We collected soil samples from 38 agricultural fields where conventional mulching films (PE), weed controlling fabrics (PP), biodegradable mulches based on polybutylene adipate terephthalate (PBAT), frost covers (PP), and oxo-degradable films (at least OXO-PE) were used. We analyzed the soils for phthalates and acetyl tributyl citrate (ATBC), used as plastic additives, and for polycyclic aromatic hydrocarbons (PAH) and dodecane that have high affinity for plastics. In comparison to the control soils, dibutylphthalate (DBP) and ATBC concentrations were significantly higher in soils mulched with PE and, partly, with biodegradable films. DBP concentration found in soil samples ranged between below the limit of quantification at a control site (1.5 μg kg-1) to 135 μg kg-1 at a site mulched with OXO-PE. The highest ATBC concentration, 22 ± 6 μg kg-1, was registered in a site mulched with PE, showing a statistically significant difference not only in comparison to the controls but also when compared to sites mulched with OXO-PE (p = 0.029) and PBAT (p < 0.009). On the contrary, the use of agricultural plastics did not influence the concentration of PAHs and dodecane. Our results indicate that agricultural plastics are a source of some organic chemicals to agricultural soils, including phthalates that are known for posing threat to soil ecosystem and human health.

Using machine learning to reveal drivers of soil microplastics and assess their stock: A national-scale study

The issue of microplastic (MP) contamination in soil is a significant concern. However, due to limited large-scale studies and stock assessments, our understanding of the drivers of their distribution and fate remains incomplete. To address this, we conducted a comprehensive study in China, collected MP data from 621 sites, and utilized machine learning techniques for analysis. Our findings revealed 9 key factors influencing the distribution of soil MPs, highlighting their nonlinear influence processes. Among these factors, atmospheric deposition emerged as the most dominant driver, while wind and precipitation could lead to the transformation of soil from a sink to a source of MPs. MP concentrations in Chinese soils vary from 1.4 to 4333.1 particles/kg, with human activities significantly affecting their distribution, resulting in higher concentrations in the east and lower concentrations in the west. The estimated MP stock in Chinese soils is 1.92 × 1018 particles, equivalent to a mass of 2.11-8.64 million tonnes. This stock alone surpasses that found in global oceans, making global soil the largest reservoir of MPs. Overall, this study enhances our understanding of the environmental behavior of MPs and provides valuable data and theoretical support for the prevention, control, and management of this contamination.

Removal of dibutyl phthalate (DBP) by bacterial extracellular polymeric substances (EPS) via enzyme catalysis and electron transmission

Phthalic acid esters (PAEs) showed high environmental risk due to the widely existence and toxicity. Microbial-excreted extracellular polymeric substances (EPS) showed potential of degrading organic compounds. In this study, the degradation ability and the mechanisms of EPS from two bacteria (PAEs degrader Gordonia sihwensis; electrochemically active strain Shewanella oneidensis MR-1) were investigated. Results showed that EPS of the two bacteria had different composition of C-type cytochromes, flavins, catalase, and α-glucosidase. The removal of dibutyl phthalate (DBP) by total EPS were 68% of G. sihwensis and 72% for S. oneidensis. For both bacteria, the degradation rates k of EPS were as TB-EPS > LB-EPS > S-EPS. The degradation mechanisms of EPS from the two bacteria showed difference with electrochemical active components mediated electron transmission for S. oneidensis MR-1 and enzymes catalysis for G. sihwensis. Results of this study illustrated the variation of the contribution of active components of EPS to degradation.

Simultaneous determination of sixteen phthalic acid esters (PAEs) in soil and evaluation of matrix effect using a QuEChERS/GC/MS-internal standard method

Phthalic acid esters (PAEs) are emerging pollutants that need to be analyzed precisely. Chromatography-based determination of PAE content in soils are frequently affected by matrix effect, which may limit the quantification of different kinds of PAEs from different types of soil. Here we optimized a QuEChERS protocol combined with gas chromatography-mass spectrometry (GC-MS) for simultaneous determination of 16 PAEs in different soils. PAEs in different type of soils (fluvo-aquic soil, red soil, and black soil) were extracted with acetonitrile followed by GC-MS detection based on quantitative ion internal standard method. All 16 PAEs showed excellent linear relationships with mass peak areas (R2 > 0.99). The limits of detection (LOD) and limits of quantitation (LOQ) of all the samples were in the range of 0.91-66.97 µg/kg and 2.7-200.9 µg/kg, respectively. The accurate test at 0.5, 0.1, and 1.0 mg/kg spiking level recorded recovery rate between 80.11% and 100.99% with relative standard deviations (RSDs) ranging from 0.37 to 8.50% in tested matrices. No significant matrix effect was observed for most tested PAEs. This is a simple method with high sensitivity and strong stability, which is suitable and reproducible for quantifying large number of PAEs in different types of soil.

Biodegradation of phthalic acid esters (PAEs) by Janthinobacterium sp. strain E1 under stress conditions

Phthalates esters (PAEs) are a kind of polymeric material additives widely been added into plastics to improve products' flexibility. It can easily cause environmental pollution which are hazards to public health. In this study, we isolated an efficient PAEs degrading strain, Janthinobacterium sp. E1, and determined its degradation effect of di-2-ethylhexyl phthalate (DEHP) under stress conditions. Strain E1 showed an obvious advantage in pollutants degradation under various environmental stress conditions. Degradation halo clearly occurred around the colony of strain E1 on agar plate supplemented with triglyceride. Strain E1's esterase is a constitutively expressed intracellular enzyme. The esterase purified from strain E1 showed a higher catalytic effect on short-chain PAEs than long-chain PAEs. The input of DEHP, DBP (dibutyl phthalate) and DMP (dimethyl phthalate) into the tested soil did not change the species composition of soil prokaryotic community, but altered the dominant species in specific environmental conditions. And the community diversity and richness decreased to a certain extent. However, the diversity and richness of the microbial community were improved after the contaminated soil was treated with the strain E1. Our results also suggested that strain E1 exhibited a tremendous potential in environmental bioremediation in the real environment, which provides a new insight into the elimination of the pollutants contamination in the urban environment.

Transcriptome mechanisms of dandelion under stress of polystyrene and dibutyl phthalate and quantitative tracing of nanoplastics

Polystyrene nanoplastics (PS NPs) and dibutyl phthalate (DBP) pollution pose significant risks to ecosystems and contribute to bioaccumulation in plants, yet uptake mechanisms and combined toxicity are poorly understood. We used fluorescent labeling and europium-doped PS NPs to reveal the absorption and translocation of NPs by dandelions and conducted a transcriptomic analysis under PS NPs and DBP exposure. The results indicated that NPs are transported horizontally through the intercellular gaps at the root tips and primary root-lateral root junctions via the apoplastic pathway, followed by longitudinal transport through the xylem vessels under the transpiration stream. Co-exposure significantly reduced the bioconcentration factors of dandelion seedlings by 113 % but increased the NP transfer factors by 33.8 %. Transcriptomic analysis confirmed that exposure to PS NPs and DBP activated gene expression in dandelion shoots and roots. The differentially expressed genes were primarily involved in the photosynthesis, plant hormone signal transduction, and phenylpropanoid biosynthesis pathways. Weighted gene co-expression network analysis identified key genes and hub transcription factors playing crucial roles in regulating dandelion's response to combined stress. Our study provides new insights into the plant toxicity mechanism underlying the interaction between PS NPs and DBP, highlighting the adverse effects of the combined pollution on plant health.

The Characteristics of Adsorption of Di-n-Butyl Phthalate by Surface Sediment from the Three Gorges Reservoir

Phthalic acid esters (PAEs), recognized as endocrine disruptors, are identified as predominant organic pollutants in the Three Gorges Reservoir (TGR). Di-n-butyl phthalate (DBP), a representative PAE, has been extensively studied for its sources, distribution and ecological risks. However, there are few studies on the adsorption of DBP by sediment from the TGR, and the adsorption characteristics of surface sediment on DBP are not clear. Therefore, based on the actual sediment contents and particle sizes in the TGR, the kinetics and isothermal adsorption characteristics of surface sediment on DBP were investigated in this study. The results showed that the equilibrium time was 120 min, the adsorption kinetics were more in line with the pseudo-second-order kinetic model, and the sediment in water from the Yangtze River exhibited a higher adsorption rate and maximum adsorption amount on DBP than that observed in deionized water. Additionally, a decrease in DBP adsorption was observed with increasing sediment content, while sediment particle size and specific surface area had a slight influence. Analysis using SEM, TGA and FTIR revealed that organic matter on the sediment surface significantly contributed to DBP adsorption. This study contributes valuable insights into the adsorption characteristics of DBP by the surface sediment from the TGR, providing a scientific foundation for understanding the migration and transformation of DBP in this critical reservoir in China.

Influencing factors and risk assessment of phthalate ester pollution in the agricultural soil on a tropical island

Phthalate esters (PAEs) are widely prevalent in agricultural soil and pose potential risks to crop growth and food safety. However, the current understanding of factors influencing the behavior and fate of PAEs is limited. This study conducted a large-scale investigation (106 sites in 18 counties with 44 crop types) of 16 types of PAEs on a tropical island. Special attention was given to the impacts of land use type, soil environmental conditions, agricultural activity intensity, and urbanization level. The health risks to adults and children from soil PAEs via multiple routes of exposure were also evaluated. The results showed that the mean concentration of PAEs was 451.87 ± 284.08 μg kg-1 in the agricultural soil. Elevated agricultural and urbanization activities contributed to more pronounced contamination by PAEs in the northern and southern regions. Land use type strongly affected the concentration and composition of PAEs in agricultural soils, and the soil PAE concentration decreased in the order of vegetable fields, orchards, paddy fields, and woodlands. In paddy fields, di-isobutyl phthalate and di-n-butyl phthalate made more substantial contributions to the process through which the overlying water inhibited volatilization. Soil microplastic abundance, pesticide usage, crop yield, gross domestic product, and distance to the nearest city were calculated to be the major factors influencing the concentration and distribution of PAEs. Soil pH, organic matter content, microplastic abundance and the fertilizer application rate can affect the adsorption of PAEs by changing the soil environment. A greater risk was detected in the northern region and paddy fields due to the higher soil PAE concentrations and the dietary structure of the population. This study reveals important pathways influencing the sources and fate of PAE pollution in agricultural soils, providing fundamental data for controlling PAE contamination.

Phthalate esters in clothing: A review

Phthalate esters (PAEs) are widely used as plasticizers to enhance the flexibility and durability of different consumer products, including clothing. However, concerns have been raised about the potential adverse health effects associated with the presence of phthalates in textiles, such as endocrine disruption, reproductive toxicity and potential carcinogenicity. Based on examination of more than 120 published articles, this paper presents a comprehensive review of studies concerning the phthalate content in clothing and other textile products, with special emphasis on those conducted in the last decade (2014-2023). The types and role of PAEs as plasticizers, the relevant legislation in different countries (emphasizing the importance of monitoring PAE levels in clothing to protect consumer health) and the analytical methods used for PAE determination are critically evaluated. The review also discusses the models used to evaluate exposure to PAEs and the associated health risks. Finally, the study limitations and challenges related to determining the phthalate contents of textile products are considered.

High concentrations of phthalates affect the early development of the sea urchin Paracentrotus lividus

The toxicity of three phthalates (PAEs) - butylbenzyl phthalate (BBP), diethyl phthalate (DEP), and di-(2-ethylhexyl) phthalate (DEHP) - was tested on the Mediterranean sea urchin Paracentrotus lividus. Fertilized eggs were exposed to environmental and high PAE concentrations for 72 h. The potential toxic effects on larval development and any morphological anomalies were then assessed to estimate PAEs impact. Environmental concentrations never affected development, while high concentrations induced toxic effects in larvae exposed to BBP (EC50: 2.9 ×103 µg/L) and DEHP (EC50: 3.72 ×103 µg/L). High concentrations caused skeletal anomalies, with a slight to moderate impact for DEP/DEHP and BBP, respectively. PAE toxicity was: BBP>DEHP>DEP. In conclusion, the three PAEs at environmental concentrations do not pose a risk to sea urchins. However, PAE concentrations should be further monitored in order not to constitute a concern to marine species, especially at their early developmental stages.

Molecular insights into the catabolism of dibutyl phthalate in Pseudomonas aeruginosa PS1 based on biochemical and multi-omics approaches

A comprehensive understanding of the molecular mechanisms underlying microbial catabolism of dibutyl phthalate (DBP) is still lacking. Here, we newly isolated a bacterial strain identified as Pseudomonas aeruginosa PS1 with high efficiency of DBP degradation. The degradation ratios of DBP at 100-1000 mg/L by this strain reached 80-99 % within 72 h without a lag phase. A rare DBP-degradation pathway containing two monobutyl phthalate-catabolism steps was proposed based on intermediates identified by HPLC-TOF-MS/MS. In combination with genomic and transcriptomic analyses, we identified 66 key genes involved in DBP biodegradation and revealed the genetic basis for a new complete catabolic pathway from DBP to Succinyl-CoA or Acetyl-CoA in the genus Pseudomonas for the first time. Notably, we found that a series of homologous genes in Pht and Pca clusters were simultaneously activated under DBP exposure and some key intermediate degradation related gene clusters including Pht, Pca, Xyl, Ben, and Cat exhibited a favorable coexisting pattern, which contributed the high-efficient DBP degradation ability and strong adaptability to this strain. Overall, these results broaden the knowledge of the catabolic diversity of DBP in microorganisms and enhance our understanding of the molecular mechanism underlying DBP biodegradation.

Biodegradation of phthalate acid esters and whole-genome analysis of a novel Streptomyces sp. FZ201 isolated from natural habitats

Di-n-butyl phthalate (DBP) is one of the most extensively used phthalic acid esters (PAEs) and is considered to be an emerging, globally concerning pollutant. The genus Streptomyces holds promise as a degrader of various organic pollutants, but PAE biodegradation mechanisms by Streptomyces species remain unsolved. In this study, a novel PAE-degrading Streptomyces sp. FZ201 isolated from natural habitats efficiently degraded various PAEs. FZ201 had strong resilience against DBP and exhibited immediate degradation, with kinetics adhering to a first-order model. The comprehensive biodegradation of DBP involves de-esterification, β-oxidation, trans-esterification, and aromatic ring cleavage. FZ201 contains numerous catabolic genes that potentially facilitate PAE biodegradation. The DBP metabolic pathway was reconstructed by genome annotation and intermediate identification. Streptomyces species have an open pangenome with substantial genome expansion events during the evolutionary process, enabling extensive genetic diversity and highly plastic genomes within the Streptomyces genus. FZ201 had a diverse array of highly expressed genes associated with the degradation of PAEs, potentially contributing significantly to its adaptive advantage and efficiency of PAE degradation. Thus, FZ201 is a promising candidate for remediating highly PAE-contaminated environments. These findings enhance our preliminary understanding of the molecular mechanisms employed by Streptomyces for the removal of PAEs.

Phthalate esters pollution in the leachate, soil, and water around a landfill near the sea, Iran

This investigation aimed to scrutinize the level of phthalate esters (PEs) in the landfill leachate of a coastal city in the north of the Persian Gulf and the sensitive ecosystem (soil and water) around it. Soil (two depths) and water samples were prepared from 5 stations in wet and dry seasons. The studied landfill leachate contained 114-303 μg/L of phthalates. The highest concentration of phthalates was related to bis (2-ethylhexyl) phthalate (3257 ng/g) in the wet season at surface soil (0-5 cm) in the landfill site, while the lowest one (6 ng/g) belonged to dimethyl phthalate at sub-surface soil at 700 m from the landfill in the dry season. A significant change in the level of Σ6PEs in the dry (303 μg/L) and wet (114 μg/L) seasons (P ≤ 0.05) was observed for water samples. The PE concentrations in wet times were higher in all soil depths than in dry times. With increasing depth, the content of phthalates decreased in all studied environments. A direct relationship was observed between the phthalates concentration and the pH value of leachate/water and soil. The PEs concentration was linked to electrical conductivity (leachate: R2 = 0.65, P < 0.01 and surface soil: R2 = 0.77, P < 0.05) and the soil organic content. The ecological risk of di-n-butyl phthalate, benzyl butyl phthalate, bis (2-ethylhexyl) phthalate, and di-n-octyl phthalate in the wet season was greater than one. The results showed that significant levels of phthalate esters are released from landfills to the surrounding environment, which requires adequate measures to maintain the health of the ecosystem and nearby residents.

Phthalate ester levels in agricultural soils of greenhouses, their potential sources, the role of plastic cover material, and dietary exposure calculated from modeled concentrations in tomato

Soil samples collected from 50 greenhouses (GHs) cultivated with tomatoes (plastic-covered:24, glass-covered:26), 5 open-area tomato growing farmlands, and 5 non-agricultural areas were analyzed in summer and winter seasons for 13 PAEs. The total concentrations (Σ13PAEs) in the GHs ranged from 212 to 2484 ng/g, wheeas the concentrations in open-area farm soils were between 240 and 1248 ng/g. Σ13PAE in non-agricultural areas was lower (35.0 - 585 ng/g). PAE exposure through the ingestion of tomatoes cultivated in GH soils and associated risks were estimated with Monte Carlo simulations after calculating the PAE concentrations in tomatoes using a partition-limited model. DEHP was estimated to have the highest concentrations in the tomatoes grown in both types of GHs. The mean carcinogenic risk caused by DEHP for tomato grown in plastic-covered GHs, glass-covered GHs, and open-area soils were 2.4 × 10-5, 1.7 × 10-5 and 1.1 × 10-5, respectively. Based on Positive Matrix Factorization results, plastic material usage in GHs (including plastic cover material source for plastic-GHs) was found to be the highest contributing source in both types of GHs. Microplastic analysis indicated that the ropes and irrigation pipes inside the GHs are important sources of PAE pollution. Pesticide application is the second highest contributing source.

Soil health hazards of di(2-ethylhexyl) phthalate: New perspectives on earthworms from different ecological niches DNA damage, gut microbial disruption and soil enzyme changes

Di(2-ethylhexyl) phthalate (DEHP) is perceived an emerging threat to terrestrial ecosystem, however, clear and accurate studies to fully understander ecotoxicity and underlying mechanisms of DEHP on the soil fauna remain poorly understood. Therefore, this study conducted a microcosm experiment of two earthworm ecotypes to investigate the ecological hazards of DHEP from multiple perspectives. The results showed that DEHP significantly increased the 8-hydroxy-deoxyguanosine (8-OHdG) content both in Eisenia foetida (13.76-133.0%) and Metaphire guillelmi (11.01-49.12%), leading to intracellular DNA damage. Meanwhile, DEHP negatively affected the expression of functional genes (ATP-6, NADH1, COX), which may be detrimental to mitochondrial respiration and oxidative stress at the gene level. The two earthworm guts shared analogous dominant bacteria however, the incorporation of DEHP drastically suppressed the homogeneity and diversity of the gut microbes, which further disrupted the homeostasis of the gut microbial ecological network. The keystone species in the gut of E. foetida decreased under DEHP stress but increased in the gut of M. guillelmi. Moreover, DEHP presented detrimental effects on soil enzyme activity, which is mainly associated with pollutant levels and earthworm activity. Collectively, the findings expand the understanding of soil ecological health and reveal the underlying mechanisms of the potential exposure risk to DEHP.

Relationship between phthalates exposure, risk of decreased ovarian reserve, and oxidative stress levels

Phthalates (PAEs), a group of environmental endocrine disruptors, are associated with oxidative stress and have adverse effects on female ovarian reserves. However, this association has been poorly investigated, particularly with respect to clinical evidence. In this study, we provided clinical evidence of a relationship between exposure levels of PAEs, oxidative stress and decreased ovarian reserve (DOR). Firstly, the urinary concentrations of metabolites of PAEs were measured by high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and anti-Mullerian hormone (AMH), and the biomarkers of oxidative stress, malondialdehyde (MDA), superoxide dismutase (SOD), and total antioxidant capacity (T-AOC), were determined. Finally, statistical analyses were conducted to describe the relationship between the PAEs exposure, oxidative stress and DOR. We found that the levels of monomethyl phthalate (MMP), monoisobutyl phthalate (MiBP), mono-(2-ethylhexyl) phthalate (MEHP), and mono-(2-ethyl-5-hydroxypentyl) phthalate (MECPP) in the DOR group were significantly higher than those in the control group. There was a significant negative association between AMH and MMP, MiBP levels. and a significant positive association between FSH and MMP levels. PAEs exposure was also associated with a significant increase in MDA levels and decrease in SOD levels. In conclusion, the exposure of PAEs was closely associated with DOR, potentially mediated by oxidative stress pathways; however, small sample size was a limitation in this study.

Pollution characteristics and affecting factors of phthalate esters in agricultural soils in mainland China

Phthalate esters (PAEs), the most commonly produced and used plasticizers, are widely used in plastic products and agroecosystems, posing risks to agricultural products and human health. However, current research on PAE pollution characteristics in agricultural soils in China is not comprehensive; affecting factors and relationships with microplastics and plasticizer organophosphate esters have not been sufficiently considered. In this study, farmland soil samples were collected with field questionnaires on a national scale across mainland China. The results showed that the detection rate of PAEs was 100% and the Σ16PAEs concentrations were 23.5 - 903 μg/kg. The level of PAEs was highest in the greenhouse, and significantly higher than that in mulched farmland (p < 0.05). The PAE concentration in northwestern China was the lowest among different physical geographic zones. PAEs in farmlands posed a low cancer risk to Chinese people. PAE pollution in farmlands was significantly (p < 0.05) affected by agronomic measures (such as disposal method), environmental factors, and socioeconomic factors. Overall, PAEs were significantly and positively correlated (p < 0.05) with organophosphate esters but not with microplastics. This study aims to provide scientific data for relevant prevention and control policies, as well as actionable recommendations for pollution reduction.

Machine learning-assisted assessment of key meteorological and crop factors affecting historical mulch pollution in China

Degraded mulch pollution is of a great concern for agricultural soils. Although numerous studies have examined this issue from an environmental perspective, there is a lack of research focusing on crop-specific factors such as crop type. This study aimed to explore the correlation between meteorological and crop factors and mulch contamination. The first step was to estimate the amounts of mulch-derived microplastics (MPs) and phthalic acid esters (PAEs) during the rapid expansion period (1993-2012) of mulch usage in China. Subsequently, the Elastic Net (EN) and Random Forest (RF) models were employed to process a dataset that included meteorological, crop, and estimation data. At the national level, the RF model suggested that coldness in fall was crucial for MPs generation, while vegetables acted as a key factor for PAEs release. On a regional scale, the EN results showed that crops like vegetables, cotton, and peanuts remained significantly involved in PAEs contamination. As for MPs generation, coldness prevailed over all regions. Aridity became more critical for southern regions compared to northern regions due to solar radiation. Lastly, each region possessed specific crop types that could potentially influence its MPs contamination levels and provide guidance for developing sustainable ways to manage mulch contamination.

Uptake and accumulation of di(2-ethylhexyl) phthalate (DEHP) in a soil-ginseng system and toxicological mechanisms on ginseng (Panax ginseng C.A. Meyer)

Di(2-ethylhexyl) phthalate (DEHP) is regarded as a priority environmental pollutant. This study explored the adsorption and accumulation of DEHP within the ginseng-soil system and the mechanism of DEHP toxicity to ginseng (Panax ginseng C.A. Meyer). Under exposure to 22.10 mg/kg DEHP in soil, DEHP mainly accumulated in ginseng leaves (20.28 mg/kg), stems (4.84 mg/kg) and roots (2.00 mg/kg) after 42 days. The oxidative damage, metabolism, protein express of ginseng were comprehensively measured and analyzed. The results revealed that MDA presented an activation trend in ginseng stems and leaves after 42 days of DEHP exposure, while the opposite trend was observed for POD. Levels of ginsenoside metabolites Rg2, Rg3, Rg5, Rd, Rf and CK decreased in the ginseng rhizosphere exudates under DEHP stress. Further investigations revealed that DEHP disrupts ginsenoside synthesis by inducing glycosyltransferase (GS) and squalene synthase (SS) protein interactions. Molecular docking indicated that DEHP could stably bind to GS and SS by intermolecular forces. These findings provide new information on the ecotoxicological effect of DEHP on ginseng root.

Response and adaptation of rhizosphere microbiome to organic pollutants with enriching pollutant-degraders and genes for bioremediation: A critical review

Phytoremediation largely involves microbial degradation of organic pollutants in rhizosphere for removing organic pollutants like polycyclic aromatic hydrocarbons, phthalates and polychlorinated biphenyls. Microbial community in rhizosphere experiences complex processes of response-adaptation-feedback up on exposure to organic pollutants. This review summarizes recent research on the response and adaptation of rhizosphere microbial community to the stress of organic pollutants, and discusses the enrichment of the pollutant-degrading microbial community and genes in the rhizosphere for promoting bioremediation. Soil pollution by organic contaminants often reduces the diversity of rhizosphere microbial community, and changes its functions. Responses vary among rhizosphere microbiomes up on different classes of organic pollutants (including co-contamination with heavy metals), plant species, root-associated niches (e.g., rhizosphere, rhizoplane and endosphere), geographical location and soil properties. Soil pollution can deplete some sensitive microbial taxa and enrich some tolerant microbial taxa in rhizosphere. Furthermore, rhizosphere enriches pollutant-degrading microbial community and functional genes including different gene clusters responsible for biodegradation of organic pollutants and their intermediates, which improve the adaptation of microbiome and enhance the remediation efficiency of the polluted soil. The knowledge gaps and future research challenges are highlighted on rhizosphere microbiome in response-adaptation-feedback processes to organic pollution and rhizoremediation. This review will hopefully update understanding on response-adaptation-feedback processes of rhizosphere microbiomes and rhizoremediation for the soil with organic pollutants.

Factors controlling the heavy metal ion activity in soil contaminated by microplastics with different mulch durations: Partial least squares path model

Film covers have been widely applied worldwide. However, the effects of long-term plastic film mulching use on heavy metal (HM) activity in soil remain unclear. This study focused on farmland in the upstream part of the Pearl River in China and collected 103 soil samples after 2, 5, and 15 years of plastic film mulching. The main environmental factors controlling microplastics (MPs), plasticizer phthalic acid esters (PAEs), HM pollution characteristics, and HM activity were analyzed. The results showed that Polyethylene (PE) and di(2-ethylhexyl) dicyclohexyl phthalate (DCHP) were the main MPs and PAEs, respectively. The abundance of MPs and the concentrations of free HM ions (Cd, Cu, and Ni) in the soil solution increased with increasing plastic film mulching duration. The Partial Least Squares Path Model (PLS-PM) indicated that after plastic film mulching, soil chemical properties (pH/amorphous Fe) and biological properties (Dissolved organic carbon/ Easily oxidizable carbon/Microbial biomass carbon) were the main controlling factors for free and complexed HM ions (Cd, Pb, Cu, and Ni). These results suggest that, after plastic film mulching, MPs indirectly regulate HM activity by altering soil properties. This study provides a new perspective for the management of MPs and HM activities in agricultural ecosystems.

Protective effects of melatonin on DEHP-induced apoptosis and oxidative stress in prepubertal testes via the PI3K/AKT pathway

Di(2-ethylhexyl) phthalate (DEHP), an environmental endocrine disruptor, is one of the most common plasticizers and is widely used in various plastic products. DEHP induces apoptosis and oxidative stress and has been shown to have androgenic toxicity. However, the methods to combat DEHP-induced testicular damage and the mechanisms involved remain to be elucidated. In the present study, we used melatonin, which has strong antioxidant properties, to intervene in prepubertal mice and mouse Leydig cells (TM3) treated with DEHP or its metabolite mono(2-ethylhexyl) phthalate (MEHP). The results showed that melatonin protected against DEHP-induced testicular damage in prepubertal mice, mainly by protecting against DEHP-induced structural destruction of the germinal tubules and by attenuating the DEHP-induced decrease in testicular organ coefficients and testosterone levels. Transcriptomic analysis found that melatonin may attenuate DEHP-induced oxidative stress and apoptosis in prepubertal testes. In vitro studies further revealed that MEHP induces oxidative stress injury and increases apoptosis in TM3 cells, while melatonin reversed this damage. In vitro studies also found that MEHP exposure inhibited the expression levels of molecules related to the PI3K/AKT signaling pathway, and melatonin reversed this change. In conclusion, these findings suggest that melatonin protects against DEHP-induced prepubertal testicular injury via the PI3K/AKT signaling pathway, and provide a theoretical basis and experimental rationale for combating male reproductive dysfunction.

Integrated transcriptomic and biochemical characterization of the mechanisms governing stress responses in soil-dwelling invertebrate (Folsomia candida) upon exposure to dibutyl phthalate

Dibutyl phthalate (DBP) is one of the most commonly utilized plasticizers and a frequently detected phthalic acid ester (PAE) compound in soil samples. However, the toxicological effects of DBP on soil-dwelling organisms remain poorly understood. This study employed a multi-biomarker approach to investigate the impact of DBP exposure on Folsomia candida's survival, reproduction, enzyme activity levels, and transcriptional profiles. Analyses of antioxidant biomarkers, including catalase (CAT) and glutathione S-transferase (GST), as well as detoxifying enzymes such as acetylcholinesterase (AChE), Cytochrome P450 (CYP450), and lipid peroxidation (LPO), revealed significant increases in CAT activity, GST levels, and CYP450 expression following treatment with various doses of DBP for 2, 4, 7, or 14 days. Additionally, LPO induction was observed along with significant AChE inhibition. In total, 3175 differentially expressed genes (DEGs) were identified following DBP treatment that were enriched in six Gene Ontology (GO) terms and 144 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, including 85 upregulated and 59 downregulated primarily associated with lipid metabolism, signal transduction, DNA repair, and cell growth and death. Overall these results provide foundational insights for further research into the molecular mechanisms underlying responses of soil invertebrates to DBP exposure.

Status of phthalate esters pollution in facility agriculture across China: Spatial distribution, risk assessment, and remediation measures

The pervasive utilization of phthalate esters (PAEs) in plastic products has led to an emergent concern regarding the PAEs contamination in environmental matrices. However, the overall understanding of PAEs pollution in facility agriculture and its relevant risks remain limited. In this paper, the characteristics, health risks, and remediation measures of PAEs pollution in facility agriculture across China were analyzed. In general, PAEs pollution in facility agriculture soil in SWC and vegetables in SC were more serious than that in the other six regions (p < 0.05). The total level of six PAEs ranged from 0.053 to 5.663 mg·kg-1 in soil samples, nd (not detectable) to 12.540 mg·kg-1 in vegetable samples, with mean values of 0.951 mg·kg-1 and 2.458 mg·kg-1, respectively. DEHP and DnBP were dominant in both soil and vegetable samples with a total contribution of over 70 % of the six PAEs, but their concentrations were a little lower in soil samples. The PAEs concentrations of leafy, root, and fruit vegetables exhibited a descending trend. Correlation analysis revealed that the relationships between soil and vegetable PAEs concentrations remained inconclusive, lacking clear correlations. Furthermore, risk assessments indicated that the hazard quotient (HQ) for both total and individual PAEs in the vast majority of vegetable samples remained within acceptable thresholds. Meanwhile, all values for carcinogenic risks (CR) were confined within the range of 10-4. In conclusion, the study outlines remediation measures aimed at precluding and mitigating the environmental risks associated with PAEs exposure. These findings furnish a scientific foundation for the targeted assessment and judicious management of PAEs pollution within facility agriculture landscape of China.

Micro (nano)plastics and phthalate esters drive endophytic bacteria alteration and inhibit wheat root growth

Endophytes play an important role in plant growth and stress tolerance, but limited information is available on the complex effects of micro (nano)plastics and phthalate esters (PAEs) on endophytes in terrestrial plants. To better elucidate the ecological response of endophytic bacteria on exogenous pollutants, a hydroponic experiment was conducted to examine the combined impact of polystyrene (PS) and PAEs on endophyte community structure, diversity, and wheat growth. The findings revealed that wheat roots were capable of absorbing and accumulating PS nanoparticles (PS-NPs, 0.1 μm), whereas PS microparticles (PS-MPs, 1 and 10 μm) merely adhered to the root surface. The addition of PAEs resulted in a stronger accumulation of fluorescent signal from PS-NPs in the roots. The dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) were identified in wheat roots, and they could be metabolized to form minobutyl phthalate and phthalic acid, and mono-(2-ethylhexyl) phthalate, respectively. Compared to single PAEs, the concentration of PAEs and their metabolites in the roots treated with PS-NPs showed a great increase, while they exhibited a significant decline in the presence of PS-MPs. Principal coordinate analysis and permutational multivariate analysis of variance demonstrated that PS size were the major factor that induced oxidative damage, and altered the endogenous homeostasis of wheat roots. The increase in PS size positively promoted the relative abundance of dominant endophytes. Specifically, Proteobacteria. Proteobacteria were the most important in the symbiosis survival, which had a great impact on the microbial community and diversity. Therefore, PS and PAEs could affect the endophytes directly and indirectly. Structural equation modeling further implied that these endophytic bacteria, along with antioxidant enzymes such as superoxide dismutase which were regulated by non-enzymatic mechanisms, promoted root biomass increase. These results indicated a synergistic resistance mechanism between antioxidant enzymes and endophytic bacteria in response to environmental stress.

Remediation of di(2-ethylhexyl) phthalate (DEHP) contaminated black soil by freeze-thaw aging biochar

Di(2-ethylhexyl) phthalate (DEHP), a complex structure with high toxicity, is a common organic pollutant. This study investigated the effects of fresh biochar (FBC), and freeze-thaw cycled aged biochar (FTC-BC) on DEHP-contaminated soils using a pot experiment. The specific surface area of FBC increased from 145.20 to 303.50 m2/g, and oxygen-containing functional groups increased from 1.26 to 1.48 mol/g after freeze-thaw cycles, greatly enhancing the adsorption of DEHP by biochar in the soil. The comprehensive radar chart evaluation showed that FBC and FTC-BC reduced DEHP growth stress and improved the soil properties. Compared with FBC, FTC-BC performed better in protecting the normal growth of pakchoi and improving soil properties. In addition, the application of biochar increased the diversity and abundance of bacteria in the DEHP-contaminated soil and changed the composition of the soil bacterial community. The partial least squares path model (PLS-PM) showed that adding biochar as a soil remediation agent significantly positively impacted soil nutrients and indirectly reduced the DEHP levels in soil and plants by increasing soil microbial diversity. Compared with FBC, FTC-BC creates a more satisfactory living environment for microorganisms and has a better effect on the degradation of DEHP in the soil. This study provides a theoretical basis for future biochar remediation of DEHP-contaminated soils in cold high-latitude regions.

Occurrence, ecological and health risk assessment of phthalates in a polluted urban river used for agricultural land irrigation in central Mexico

The escalating global concern on phthalate esters (PAEs) stems from their status as emerging contaminants, marked by their toxicity and their potential to harm both the environment and human health. Consequently, this study aimed to evaluate the occurrence, spatial distribution, and ecological and health risks associated with PAEs in the Atoyac River, an urban waterway in central Mexico that receives untreated and poorly treated urban and industrial wastewater. Of the 14 PAEs analyzed in surface water samples collected along the river mainstream, nine were detected and quantified by GC-MS. The concentration of each detected PAE ranged from non-detected values to 25.7 μg L-1. Di (2-ethylhexyl) phthalate (DEHP) and di-n-hexyl phthalate (DnHP) were detected in all sampling sites, with concentrations ranging from 8.1 to 19.4 μg L-1 and from 6.3 to 15.6 μg L-1, respectively. The cumulative Σ9PAEs concentrations reached up to 81.1 μg L-1 and 96.0 μg L-1 in sites downstream to high-tech industrial parks, pinpointing industrial wastewater as the primary source of PAEs. Given that the river water is stored in a reservoir and used for cropland irrigation, this study also assessed the ecological and human health risks posed by PAEs. The findings disclosed a high ecological risk to aquatic organisms exposed to di-n-octyl phthalate (DOP), dicyclohexyl phthalate (DCHP), benzyl butyl phthalate (BBP), DEHP, and DnHP. Additionally, a high carcinogenic (CR > 10-4) and noncarcinogenic (HQ > 10) risk for the DEHP exposure through ingestion of crops irrigated with river water was identified for both children and adults. These data on PAEs provide valuable insights for the Mexican government's future strategies in regulating these pollutants in water bodies, thereby minimizing the environmental and human health risks that they pose.

Combined Astragalus, vitamin C, and vitamin E alleviate DEHP-induced oxidative stress and the decreased of insulin synthesis and secretion in INS-1 cells

Di-(2-ethylhexyl)-phthalate (DEHP), a common Phthalic acid ester (PAEs), has been reported to be associated with diabetes mellitus, yet the underlying mechanisms remain unknown. Combined nutrient interventions have been shown to alleviate the diabetic toxicity of DEHP. However, the effects and mechanisms of the combined intervention of Astragalus and vitamins (C and E) are currently unknown. In this study, we investigated the potential mechanisms of DEHP-induced diabetes mellitus through transcriptome analysis and vitro experiments using rat insulinoma cells (INS-1 cells). Furthermore, we explored the protection of the combined Astragalus, vitamin C, and vitamin E on DEHP-induced diabetes mellitus through these mechanisms. INS-1 cells in the logarithmic growth period were exposed to 125 umol/L DEHP followed by high-throughput sequencing analysis. The cell proliferation inhibition rate was determined using MTT assay for each group, and the cell apoptosis rate and intracellular ROS level were measured using flow cytometer. Finally, insulin levels and markers of oxidative stress were detected using ELISA kits in different groups. A total of 372 differentially expressed genes were found between the 125 umol/L DEHP and control groups, subsequent functional enrichment analyses indicated that DEHP induced oxidative stress and disturbed insulin levels. In INS-1 cells, the rate of cell proliferation inhibition, apoptosis, and the degree of oxidative stress increased concentration-dependently with increasing DEHP concentrations, while antioxidant intervention could reverse these changes. Insulin synthesis and secretion decreased after 240 μmol/L DEHP exposure stimulated by 25 mM glucose in INS-1 cells, also could antioxidant intervention alleviate these reductions. Based on these results, the underlying mechanism of DEHP impairing the function of INS-1 cells might be through apoptosis pathways induced by oxidative stress and direct reduction of insulin levels (both synthesis and secretion), while the optimal combination of Astragalus and vitamins (C and E) could exert an alleviating effect.

Occurrence of metals, phthalate esters, and perfluoroalkyl substances in cellar water and their relationship with bacterial community in rural areas of China

Water cellars are traditional rainwater harvesting facilities that have been widely used in rural areas of northwest China. However, there are few reports about the water quality and health risk caused by the cellar water, especially phthalate esters (PAEs) and perfluoroalkyl substances (PFASs). This study investigated and assessed the health risks caused by the metals, PAEs, PFASs and bacterial communities in cellar water. The results showed that the turbidity and total number of bacterial colonies ranged from 4.7 to 58.5 NTU and 5-557 CFU/mL, respectively. The turbidity and total number of bacterial colonies were the main water quality problems. Due to high concentration of Tl (0.005-0.171 μg/L), the samples reached a high level of metal pollution. PAEs showed no non-carcinogenic and carcinogenic risk. The perfluorobutanoic acid (PFBA), perfluorobutanesulfonic acid (PFBS), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS) were the main components of PFASs. PFOA and PFOS reached a moderate risk level in many cellar water samples. Moreover, Tl, Pb, As, PFBA and PFBS could change the bacterial community composition and induce the enrichment of bacterial functions related to human diseases. Besides these parameters, dissolved oxygen (DO) also affected the bacterial functions related to human diseases. Therefore, more attention should be paid to turbidity, DO, Tl, Pb, As, PFOA, PFOS, PFBA and PFBS in the cellar water. These results are meaningful for the water quality guarantee and health protection in rural areas of China.

What government interventions are effective in regulating the use and recycling of high-standard mulch film in China?

The widespread use of ultra-thin mulch films has been considered the root cause of China's difficulties in recycling waste mulch films and their severe residue and pollution. Therefore, environmental regulation to guide farmers to use and recycle high-standard mulch has become a key measure to prevent and control mulch pollution at the source. In this paper, we review environmental regulation measures for mulch pollution and their implementation characteristics in the northwest dry farming restoration region as a case study, and explore their impact on the use and recycling of high-standard mulch. ​The results show that China's environmental regulations on mulch use and recycling can be classified into three types: guidance, incentives, and restrictions. However, the measures implemented so far primarily consist of guidance, while the restrictive and incentive regulations are inadequate. The percentage of farmers using and recycling high-standard mulch under environmental regulations is relatively high (88.18% and 79.83%, respectively), but there is still room for improvement. The study also reveals that while environmental regulations promote the use of high-standard plastic film and its recycling, not all measures are equally effective. Specifically, the implementation of measures such as benefits publicity, price subsidies, technical training, behavior supervision, and punishment mechanisms can be effective in improving farmers' adoption of high-standard plastic mulch; publicizing the hazards of mulch residue, training on recycling techniques, establishing recycling sites, regulating recycling practices, and penalizing violations can effectively help increase the recycling rate of used mulch film. Finally, this study provides a valuable reference for improving regulatory policies for mulch pollution control.

Comprehensive model development based on Dempster-Shafer evidence theory for pollution source analysis in chemical parks

Pollution source analysis is an effective method that can help chemical park managers accurately understand the characteristics and contributions of pollution sources in the park. However, as more receptor models are being used in this field, it has become difficult for managers to find the best interpretable and reasonable model among many source analysis models. Here, we present a case study of pollution source analysis in a southern chemical park using the D-S evidence theory approach to combine the source analysis results of different receptor models for comprehensive consideration. Receptor models were used to analyse the pollution sources via positive definite matrix decomposition, principal component analysis-multiple linear regression, and Unmix models. The results demonstrated that source analysis was greatly influenced by the uniqueness of pollutant characteristics and model receptor differences. Furthermore, incomparable analysis results and low fineness were observed. The D-S evidence theory model proposed in this study solved the above-mentioned problem to some extent and successfully extracted the four primary pollution sources in the study area, of which 45.73 % came from the metal processing industry (F1), whose primary pollutants were Cr, Ni, Zn, Cr(VI), and Cu, and 25.12 % came from the electronics manufacturing industry (F2), whose primary pollutants were Pb, Cr(VI), Cu, and Zn. 15.62 % of the contamination came from the production of chemical agents (F3), whose primary pollutant was TEHP, and 13.53 % came from the use of oil-containing auxiliary materials (F4), whose primary pollutant was TPH. The D-S evidence theory model used in this study provides a reference for the management of chemical parks.

Best management practices for minimizing undesired effects of thermal remediation and soil washing on soil properties. A review

The use of remediated soils as end-of-life materials raises some challenges including policy and regulation, permits and specifications, technological limitations, knowledge and information, costs, as well as quality and performance associated with using them. Therefore, a set of procedures must be followed to preserve the quality and fundamental properties of soil during a remediation process. This study presented a comprehensive review regarding the fundamental impacts of thermal desorption (TD) and soil washing (SW) on soil characteristics. The effects of main operating parameters of TD and SW on the physical, chemical, and biological properties of soil were systematically reviewed. In TD, temperature has a more remarkable effect on physic-chemical and biological characteristics of soil than heating time. Therefore, decrease in temperature within a suitable range prevents unreversible changes on soil properties. In SW, more attention should be paid to extraction process of contaminants from soil particles. Using the right dosage and type of chelating agents, surfactants, solvents, and other additives can help to avoid problems with recovery or treatment using conventional methods. In addition, this review introduced a framework for implementing sustainable remediation approaches based on a holistic approach to best management practices (BMPs), which, besides reducing the risks associated with different pollutants, might provide new horizons for decreasing the unfavourable impacts of TD and SW on soil.

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.

Effects of phthalate and bisphenol plasticizers on the activity of glycolytic enzymes of the moth Spodoptera littoralis

Environmental plastic pollution has significantly increased in the recent decades, and severely impacts economies, human and biodiversity health. Plastics are made of several chemical additives, including bisphenol and phthalate plasticizers such as bisphenol A (BPA) and Di(2-ethylhexyl)phthalate (DEHP). In some animal species, both BPA and DEHP are known as endocrine disruptor compounds, and can alter physiological and metabolic homeostasis, reproduction, development and/or behavior. To date, the impacts of BPA and DEHP have mainly focused on vertebrates, and to a lesser extent, on aquatic invertebrates. Yet, the few studies which examined the effects of DEHP on terrestrial insects also revealed the impacts this pollutant can have on development, hormone titrations, and metabolic profiles. In particular, it has been hypothesized in the Egyptian cotton leafworm Spodoptera littoralis that the observed metabolic alterations could result from the energetic costs necessary for DEHP detoxification or to the dysregulation of hormonally-controlled enzymatic activities. To get additional insights into the physiological effects of bisphenol and phthalate plasticizers on the moth S. littoralis, larvae were fed with food contaminated by BPA, DEHP, or the mixture of both compounds. Then, activities of four glycolytic enzymes, hexokinase, phosphoglucose isomerase, phosphofructokinase, and pyruvate kinase were measured. BPA and/or DEHP had no effects on the activities of phosphofructokinase and pyruvate kinase. Conversely, BPA-contaminated larvae were characterized by a 1.9-fold increase in phosphoglucose isomerase activity, and BPA + DEHP-fed larvae had highly variable hexokinase activity. Overall, since no disruption of glycolytic enzyme was observed in DEHP-contaminated larvae, our work tended to demonstrate that exposure to bisphenol and DEHP increased the amount of oxidative stress experienced.

Environmental health risks induced by interaction between phthalic acid esters (PAEs) and biological macromolecules: A review

As a kind of compounds abused in industry productions, phthalic acid esters (PAEs) cause serious problems in natural environment. PAEs pollution has penetrated into environmental media and human food chain. This review consolidates the updated information to assess the occurrence and distribution of PAEs in each transmission section. It is found that micrograms per kilogram of PAEs are exposed to humans through daily diets. After entering the human body, PAEs often undergo the metabolic process of hydrolysis to monoesters phthalates and conjugation process. Unfortunately, in the process of systemic circulation, PAEs will interact with biological macromolecules in vivo under the action of non-covalent binding, which is also the essence of biological toxicity. The interactions usually operate in the following pathways: (a) competitive binding; (b) functional interference; and (c) abnormal signal transduction. While the non-covalent binding forces mainly contain hydrophobic interaction, hydrogen bond, electrostatic interaction, and π interaction. As a typical endocrine disruptor, the health risks of PAEs often start with endocrine disorder, further leading to metabolic disruption, reproductive disorders, and nerve injury. Besides, genotoxicity and carcinogenicity are also attributed to the interaction between PAEs and genetic materials. This review also pointed out that the molecular mechanism study on biological toxicity of PAEs are deficient. Future toxicological research should pay more attention to the intermolecular interactions. This will be beneficial for evaluating and predicting the biological toxicity of pollutants at molecular scale.

Origin, dietary exposure, and toxicity of endocrine-disrupting food chemical contaminants: A comprehensive review

Endocrine-disrupting chemicals (EDCs) are a growing public health concern worldwide. Consumption of foodstuffs is currently thought to be one of the principal exposure routes to EDCs. However, alternative ways of human exposure are through inhalation of chemicals and dermal contact. These compounds in food products such as canned food, bottled water, dairy products, fish, meat, egg, and vegetables are a ubiquitous concern to the general population. Therefore, understanding EDCs' properties, such as origin, exposure, toxicological impact, and legal aspects are vital to control their release to the environment and food. The present paper provides an overview of the EDCs and their possible disrupting impact on the endocrine system and other organs.

New insight into phytometabolism and phytotoxicity mechanism of widespread plasticizer di (2-ethylhexyl) phthalate in rice plants

Di-(2-ethylhexyl) phthalate (DEHP) as widely utilized plasticizer has aroused increasing concerns since its endocrine disrupting effects and continuous accumulation in biota. To date, the interaction mechanism between DEHP and rice plants has not been clearly illustrated at molecular level. Here, we investigated biological transformation and response of rice plants (Oryza sativa L.) to DEHP at realistic exposure concentrations. Nontargeted screening by UPLC-QTOF-MS was used to verify 21 transformation products derived from phase I metabolism (hydroxylation and hydrolysis) and phase II metabolism (conjugation with amino acids, glutathione, and carbohydrates) in rice. MEHHP-asp, MEHHP-tyr, MEHHP-ala, MECPP-tyr and MEOHP-tyr as the conjugation products with amino acids are observed for the first time. Transcriptomics analyses unraveled that DEHP exposure had strong negative effects on genes associated with antioxidative components synthesis, DNA binding, nucleotide excision repair, intracellular homeostasis, and anabolism. Untargeted metabolomics revealed that metabolic network reprogramming in rice roots was induced by DEHP, including nucleotide metabolism, carbohydrate metabolism, amino acid synthesis, lipid metabolism, synthesis of antioxidant component, organic acid metabolism and phenylpropanoid biosynthesis. The integrated analyses of interaction between differentially expressed genes (DEGs) and differentially expressed metabolites (DEMs) endorsed that metabolic network regulated by DEGs was significantly interfered by DEHP, resulting in cell dysfunction of roots and visible growth inhibition. Overall, these finding generated fresh perspective for crops security caused by plasticizer pollution and enhanced the public focus on dietary risk.

Dibutyl Phthalate Adsorbed on Multiwalled Carbon Nanotubes Causes Fetal Developmental Toxicity in Balb/C Mice

This study investigated whether using multiwalled carbon nanotubes (MWCNTs) as a carrier for dibutyl phthalate (DBP) could delay the degradation rate of DBP in mice and increase its estrogen-like interference effect. Pregnant Balb/C mice were divided into four groups and exposed to different treatments via tail-vein injection every 3 days until gestational day 20. The female and male mice were then sacrificed for toxicological study. The results showed that the combination of MWCNTs and DBP resulted in a higher fetal mortality rate than if the mice were exposed to MWCNTs or DBP alone. H&E staining showed that the estrous period of the exposed mice was delayed, the development of oocytes was blocked in the combination group, the number of spermatogenic cells decreased, and the quality of sperm decreased. Our experiment showed that the expression levels of the genes involved in sex hormone synthesis in the testis and ovaries were significantly increased after combined treatment compared with the MWCNT group (p < 0.01). The study suggests that DBP degradation is delayed when absorbed on MWCNTs, which increases its estrogen-like interference and interferes with fetal development, ultimately leading to increased fetal mortality.

Rice genotypes and root-associated niches shifted bacterial community in response to pollution of di-(2-ethylhexyl) phthalate (DEHP) for promoting DEHP removal

Organic pollutants influenced root-associated bacterial community. However, the response variation of root-associated bacterial community among different rice genotypes exposed to phthalates (PAEs) and their removal mechanism remains unknown. Here, bacterial community and PAE-degrading genes in root-associated niches were analyzed between low (Fengyousimiao) and high (Hhang) PAE-accumulating rice cultivars exposed to di-(2-ethylhexyl) phthalate (DEHP). DEHP dissipation percentages in rhizosphere of Hhang were significantly higher than those of Fengyousimiao. The bacterial community diversities (including Chao1 and Shannon index) significantly decreased along bulk soil - rhizosphere - rhizoplane - endosphere. The bacterial community structures were shaped mainly by root-associated niches, DEHP pollution and rice genotypes, with significant differences in rhizosphere and rhizoplane between Fengyousimiao and Hhang. Rhizosphere enriched more PAE-degrading bacteria than in bulk soil, and exhibited significantly higher expression of PAE-degrading genes (hydrolase 65, phtab, phtC, pcaF and pcaI) than in bulk soil. Furthermore, rhizosphere of Hhang demonstrated significantly stronger bacterial functions related to xenobiotics biodegradation and higher expression of PAE-degrading genes than those of Fengyousimiao, leading to significantly higher DEHP dissipation percentages in rhizosphere of Hhang. The findings demonstrate that Hhang shaped specific root-associated bacterial community with higher abundances of PAE-degrading bacteria and genes than Fengyousimiao to promote DEHP degradation.

Degradation characteristics of polybutylene adipate terephthalic acid (PBAT) and its effect on soil physicochemical properties: A comparative study with several polyethylene (PE) mulch films

The degradation process of different types of mulch in agriculture and its effect on soil ecosystem should be considered comprehensively. To this end, the changes in performance, structure, morphology, and composition of PBAT film during the degradation process were examined through a multiscale approach in comparison with several PE films and their effects on the soil physicochemical properties were investigated. At the macroscopic scale, the load and elongation of all films decreased with increasing ages and depths. At the microscopic scale, the stretching vibration peak intensity (SVPI) for PBAT and PE films decreased by 48.8 ∼ 60.2% and 9.3 ∼ 38.6%, respectively. The crystallinity index (CI) increased by 67.3 ∼ 209.6% and 15.6 ∼ 21.8%, respectively. At the molecules scale, terephthalic acid (TPA) was detected in localized soil with PBAT mulch after 180 d. In short, the degradation characteristics of PE films were depended on their thickness and density. The PBAT film exhibited the highest degree of degradation. Simultaneously, the soil physicochemical properties such as soil aggregates, microbial biomass and pH were affected by the changes of film structure and components during the degradation process. This work has practical implications for the sustainable development of agriculture.

Widespread distribution of phthalic acid esters in indoor and ambient air samples collected from Hanoi, Vietnam

In the present study, distribution characteristics of ten typical phthalic acid esters (PAEs) were investigated in 90 air samples collected from the urban areas in Hanoi, Vietnam from May to August 2022. The total concentrations of PAEs in indoor and ambient air samples were in the range of 320-4770 ng/m³ and 35.9-133 ng/m³, respectively. Total concentrations of PAEs in indoor air were about one order of magnitude higher than those in ambient air. Among PAEs studied, di-(2-ethyl)hexyl phthalate (DEHP) was measured at the highest levels in all air samples, followed by di-n-octyl phthalate (DnOP) and di-n-butyl phthalate (DnBP). The PAEs concentrations in air samples collected from laboratories at nighttime were significantly higher than those during daytime (p < 0.05). Meanwhile, the distributions of PAEs in various micro-environments in the same house are no statistically significant difference. The median exposure doses of PAEs through inhalation for adults and children were 248 and 725 ng/kg-bw/d, respectively. These exposure levels were still lower than the respective reference doses (RfD) proposed by the US EPA for selected compounds such as diethyl phthalate (DEP), DnBP, and DEHP.

Phthalate esters and their metabolites in paired soil-crop systems from farmland in major provinces of eastern China: Pollution characteristics and implications for human exposure

The extensive application of phthalate esters (PAEs) as plasticizers has raised considerable concern regarding their environmental load, but the associated occurrence of PAE metabolites has often been ignored. The soil-plant system is a vital source of human exposure to PAEs via crop intake. Here, paired soil-plant samples were collected from eastern China to investigate the occurrence characteristics of seven PAE congeners and two primary monoester phthalate metabolites (mPAEs) in farmland. The detection frequencies of PAEs and mPAEs in the investigated soil-plant systems were 100 %. The total concentrations of PAEs in the collected soil and plant samples ranged from 0.07 to 1.83 mg/kg (dw) and from 3.9 to 24 mg/kg (dw), respectively. Moreover, di-(2-ethylhexyl) phthalate, diisobutyl phthalate and di-n-butyl phthalate were the predominant PAE congeners in the farmlands of eastern China, collectively accounting for >90 % of the total concentration of PAEs. In addition, the total concentrations of the two mPAEs were markedly higher in plant samples (49 ng/g dw to 549 ng/g dw) than in soil samples (3 ng/g dw to 22 ng/g dw), indicating that PAEs are readily metabolized in plants. The hazard index (HI) values of all PAEs in all crops were <1, demonstrating that the risks of PAEs in the crops were acceptable. However, the daily intake of mPAEs from the consumption of cabbage was higher than or comparable to that of some PAEs (such as di-n-octyl phthalate). This highlights the importance of taking metabolites into consideration in further environmental investigations and risk assessments of PAEs.

DBP induced autophagy and necrotic apoptosis in HepG2 cells via the mitochondrial damage pathway

Phthalate esters (PAEs) are widely present in human tissues and pose significant health risks. In this study, HepG2 cells were treated with 0.0625, 0.125, 0.25, 0.5 and 1 mM Dibutyl phthalate (DBP) for 48 h to investigate mitochondrial toxicity. The results showed that DBP caused mitochondrial damage, autophagy, apoptosis and necroptosis; Transcriptomics analysis identified that MAPK and PI3K were significant factors in the cytotoxic changes induced by DBP; N-Acetyl-L-cysteine (NAC), SIRT1 activator, ERK inhibitor, p38 inhibitor and ERK siRNA treatments counteracted the changes of SIRT1/PGC-1α and Nrf2 pathway-related proteins, autophagy and necroptotic apoptosis proteins induced by DBP. While PI3K and Nrf2 inhibitors exacerbated the changes in SIRT1/PGC-1α, Nrf2-associated proteins and autophagy and necroptosis proteins induced by DBP. In addition, the autophagy inhibitor 3-MA alleviated the increase in DBP-induced necroptosis proteins. These results suggested that DBP-induced oxidative stress activated the MAPK pathway, inhibited the PI3K pathway, which in turn inhibited the SIRT1/PGC-1α pathway and Nrf2 pathway, thereby causing cell autophagy and necroptosis.

Ecotoxicological and biochemical effects of di(2-ethylhexyl)phthalate on wheat (Jimai 22, Triticum aestivum L.)

Di(2-ethylhexyl)phthalate esters (DEHP) has attracted widespread attention due to its ecotoxicological effects on organisms. In this study, wheat seedlings were exposed to DEHP- contaminated soil with 4 concentration gradients (0, 1, 10, and 100 mg kg^-1, respectively) for 30 days. The growth index, physiological index, oxidative damage system, and gene expression of wheat seedlings were comprehensively measured and analyzed. The results revealed that DEHP could reduce the germination rate of wheat. Only the 100 mg kg^-1 treatment group significantly inhibited root length, but no effect on plant height. At the biochemical level, photosynthetic pigments of wheat seedlings were promoted first and then inhibited, while the soluble sugar content presented a trend of "inhibition - activation - inhibition". The antioxidant enzymes (SOD and POD) presented an approximate parabolic trend, while it was opposite for CAT. Whereas the corresponding antioxidant enzyme genes were up-regulated, and the Hsp70 heat-shock protein gene was down-regulated. Finally, integrated biological response index (IBR) analysis showed that the DEHP toxicity to wheat seedlings was dose dependent. Molecular docking indicated that DEHP could stably bind to GBSS and GST by intermolecular force. Overall, this study provided constructive insights for a comprehensive assessment of the toxicity risk of DEHP to wheat.

Fluorescent labeling and tracing of immobilized efficient degrading bacterium DNB-S1 and its remediation efficiency of DBP contaminated soil

Dibutyl phthalate (DBP) is an organic pollutant frequently detected in soil, and is a reproductive poison that harms animals both before and after birth and has mutagenic, teratogenic, and carcinogenic effects. DBP removal from farmland has been the subject of extensive research in recent years. Efficient DBP degrading bacterial strains were screened in the laboratory. GFP (Green fluorescent protein) labeled degradation strain GFP-DNB-S1 was analyzed for its activity and dynamics. Using sodium alginate (SA) and nano-hydroxyapatite (n-HAP) as carrier materials and CaCl₂ as a cross-linking agent, the immobilized microbial agent n-HAP/SA + DNB-S1 was prepared by embedding cross-linking immobilization technology to study the remediation effect of DBP contaminated soil. The best formation effect of immobilized materials (n-HAP/SA) was found when the SA to n-HAP ratio was 3:2. When compared to single SA immobilized bacteria, n-HAP/SA immobilized bacteria improved the surface roughness and porosity of the microspheres. After 70 days, LED light revealed that the immobilized bacteria's GFP green fluorescent protein expression was stable. At 70 days, the initial DBP concentration of 500 mg ∙ L^-1 degraded at a rate of 69.9%. The degrading bacteria had no effect on DBP degradation before and after being labeled with GFP. The n-HAP/SA immobilized bacteria offered a better living environment for microorganisms due to their rougher surface and a greater number of pores. This protected the microorganisms and increased the efficiency of DBP degradation. When the concentration of DBP in contaminated soil was set to 20 mg ∙ kg^-1 and the n-HAP/SA + DNB-S1 immobilized bacterial agent was applied to the soil, the rate of DBP degradation was determined to be 93.34%. The degradation process followed First-order degradation kinetics, which improved the physical and chemical properties of the soil as well as its fertility.

Pollution characteristics and health risk assessment of phthalate esters in agricultural soil of the Yellow River Delta, China

A total of 100 agricultural soil samples, collected in the Yellow River Delta, China, were analyzed for six U.S. Environmental Protection Agency priority phthalate esters (PAEs), focusing on the characteristics of PAEs contamination and potential health risks. The detection frequencies of ∑₆PAEs were 100%, where the concentration ranged from 1.087 to 14.391 mg·kg^-1, with a mean value of 4.149 mg·kg^-1. The most abundant PAEs were di(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DnBP). The areas with higher contents of ∑₆PAEs are distributed in the western and central parts of the Yellow River Delta region and around Laizhou Bay. PAEs in the Yellow River Delta agricultural soil were attributed to pollutant emissions from petrochemical industries, plasticizers or additives, fertilizers, and pesticides. The non-carcinogenic risk of human exposure to PAEs in agricultural soils is relatively low, but the non-carcinogenic risk is higher in children than in adults, and children are a sensitive group. Under the dietary route, both DEHP and ∑₂PAEs (BBP, and DEHP) pose some degree of carcinogenic risk to both local adults and children. Efforts must be made to enhance the prevention and control of PAEs contamination of agricultural soils in the Yellow River Delta region to reduce the potential risk to humans.

Evaluation of soil ecological health after exposure to environmentally relevant doses of Di (2-ethylhexyl) phthalate: Insights from toxicological studies of earthworms at different ecological niches

As one of the most critical soil faunas in agroecosystems, earthworms are significant in preserving soil ecological health. Di (2-ethylhexyl) phthalate (DEHP) is a major plasticizer and widely used in plastic products like agricultural films. However, it has become ubiquitous contaminant in agricultural soil and poses a potential threat to soil health. Although the awareness of the impacts of DEHP on soil ecology is increasing, its adverse effects on soil invertebrates, especially earthworms, are still not well developed. In this study, the ecotoxicological effects and underlying mechanisms of environmentally relevant doses DEHP on earthworms of different ecological niches were investigated at the individual, cytological, and biochemical levels, respectively. Results showed that the acute toxicity of DEHP to M. guillelmi was higher than E. foetida. DEHP induced reactive oxygen species (ROS) levels and further caused oxidative damage (including cellular DNA and lipid peroxidation damage) in both species, speculating that they may exhibit similar oxidative stress mechanisms. Furthermore, two earthworms presented the alleviated toxicity when re-cultured in uncontaminated circumstances, yet, the accumulated ROS in bodies could not be completely scavenged. Risk assessment indicated that the detrimental impacts of DEHP were more significant in the M. guillelmi than in E. foetida in whole experiments prides, and the biomarkers additionally showed a species-specific trend. Besides, molecular docking revealed that DEHP could bind to the active center of superoxide dismutase/catalase (SOD/CAT) by hydrogen bonding or hydrophobic interactions. Overall, this study will provide a novel insight for accurate contaminant risk assessment, and also highlight that the comprehensive biological effects of different species should be emphasized in soil ecological health diagnostics and environmental toxicology assays, as otherwise it may lead to underestimation or misestimation of the soil health risk of contaminants.

Environmentally relevant perinatal exposure to DBP accelerated spermatogenesis by promoting the glycolipid metabolism of Sertoli cells in male offspring mice

Since Sertoli cells (SCs) play an essential role in providing energy for spermatogenesis, the present study aimed to investigate the effects of maternal exposure to plasticizer Dibutyl phthalate (DBP) on the onset of spermatogenesis in male offspring through the metabolism pathway as well as the underlying molecular mechanism. Here, pregnant mice were treated with 0 (control), 50, 250, or 500 mg/kg/day DBP in 1 mL/kg corn oil administered daily by oral gavage from gestation day (GD) 12.5 to parturition. The in vivo results showed that 50 mg/kg/day DBP exposure could promote the expression of glucose metabolism-related proteins (GLUT3, LDHA, and MCT4) in the testis of 22 days male offspring. The in vitro results demonstrated that 0.1 mM monobutyl phthalate (MBP, the active metabolite of DBP) promoted the lactate production, glucose consumption, and glycolytic flux of immature SCs, which was paralleled by the upregulated expression of glucose metabolism-related proteins (GLUT1, GLUT3, LDHA, and MCT4). On the other hand, DBP/MBP increased fatty acid (FA) uptake, FA β-oxidation, and ATP production by promoting the expression of CD36 in immature SCs, which might accelerate the maturity of SCs to support the onset of spermatogenesis. Therefore, our findings provided a new perspective on glycolipid metabolism to explain prenatal DBP exposure leading to earlier onset of spermatogenesis in male offspring mice.