Uptake of di-(2-ethylhexyl) phthalate of vegetables from plastic film greenhouses

Phthalates Induce Neurotoxicity by Disrupting the Mfn2-PERK Axis-Mediated Endoplasmic Reticulum-Mitochondria Interaction

Di-(2-ethylhexyl) phthalate (DEHP), as the most common phthalate, has been extensively used as a plasticizer to improve the plasticity of agricultural products, which pose severe harm to human health. Mitochondrial dynamics and endoplasmic reticulum (ER) homeostasis are indispensable for maintaining mitochondria-associated ER membrane (MAM) integrity. In this study, we aimed to explore the effect of DEHP on the nervous system and its association with the ER-mitochondria interaction. Here, we showed that DEHP caused morphological changes, motor deficits, cognitive impairments, and blood-brain barrier disruption in the brain. DEHP triggered ER stress, which is mainly mediated by protein kinase R-like endoplasmic reticulum kinase (PERK) signaling. Moreover, DEHP-induced mitofusin-2 (Mfn2) downregulation results in imbalance of the mitochondrial dynamics. Interestingly, DEHP exposure impaired MAMs by inhibiting the Mfn2-PERK interaction. Above all, this study elucidates the disruption of the Mfn2-PERK axis-mediated ER-mitochondria interaction as a phthalate-induced neurotoxicity that could be potentially developed as a novel therapy for neurological diseases.

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.

Potential toxic components in size-resolved particles and gas from residential combustion: Emission factor and health risk

Particulate matter (PM) from residential combustion is an existential threat to human health. Emission factors (EFs) of multiple potential toxic components (PTCs) in size-resolved PM and gas from eight residential fuel combustion were measured, and size distribution, gas/particle partitioning and health risks of the PTCs were investigated. Average EFs from clean coal and anthracite coal were PTEs (sum of EFs of 11 Potential Toxic Elements, 6.62 mg/kg fuels) > PAHs (sum of 22 Polycyclic Aromatic Hydrocarbons, 1.12 mg/kg) > OPAHs (sum of 5 Oxygenated Polycyclic Aromatic Hydrocarbons, 0.45 mg/kg) > PAEs (sum of 6 Phthalate Esters, 0.11 mg/kg) > NPAHs (sum of 14 Nitropolycyclic Aromatic Hydrocarbons, 16.84 μg/kg) > OPEs (sum of 7 Organophosphate Esters, 7.57 μg/kg) > PCBs (sum of 6 Polychorinated Biphenyls, 0.07 μg/kg), which were 2-3 and 1-2 orders of magnitude lower than the EFs of PTCs (except PTEs) from bituminous coal and biomass. Most PAHs, OPAHs and NPAHs, which may mainly originate from chemical reactions, showed similar size distributions and averagely 85 % concentrated in PM1. PTEs, PAEs, OPEs and PCBs generated from the release from raw fuels may have a higher proportion, so their size distributions were more complex and varied with combustion temperature, volatility of compounds, binding mode of the raw fuels, and so on. In addition, clean coal and high-quality anthracite coal could reduce the health risks from the potential organic toxic components, but also reveal the stumbling block of PTEs in risk control.

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.

Distribution of Micro-Nano PS, DEHP, and/or MEHP in Mice and Nerve Cell Models In Vitro after Exposure to Micro-Nano PS and DEHP

Polystyrene (PS) and di-(2-ethylhexyl) phthalate (DEHP) exist widely in the environment. However, their distribution in organisms remains unclear. We used three sizes (50 nm, 500 nm, and 5 μm) of PS and DEHP to study the distribution and accumulation of PS, DEHP, and mono(2-ethylhexyl) phthalate (MEHP) in mice and nerve cell models (HT22 and BV2 cells) and their potential toxicity. Results showed that PS entered the blood of mice, and the distribution of different particle sizes in different tissues was different. After the combined exposure to PS and DEHP, PS carried DEHP, which significantly increased the DEHP content and MEHP content and the highest content of MEHP was in the brain. With the decrease in PS particle size, the contents of PS, DEHP, and MEHP in the body increased. The levels of inflammatory factors were increased in the serum of the PS or/and DEHP group. In addition, 50 nm polystyrene can carry MEHP into nerve cells. These results suggest for the first time that PS and DEHP combined exposure can induce systemic inflammation, and the brain is an important target organ of PS and DEHP combined exposure. This study may serve as a reference for further evaluation of the neurotoxicity induced by combined exposure to PS and DEHP.

Thickness-dependent release of microplastics and phthalic acid esters from polythene and biodegradable residual films in agricultural soils and its related productivity effects

It is crucial to elucidate the release rate of microplastics (MPs) and phthalic acid esters (PAEs) in agricultural soil and their effects on crop productivity regarding film types and thicknesses. To address this issue, two-year landfill test was performed using 0.016 mm-thick polyethylene (PEt1) & biodegradable (BIOt1), and 0.01 mm-thin polyethylene (PEt2) & biodegradable (BIOt2) residual films as materials with no landfill as CK. Scanning electron microscopy (SEM) and infrared analyses revealed that two-year landfill caused considerable changes in physical forms and spectral peaks in BIO film, which was more pronounced in thin BIO (36.90 % weight loss). Yet, less changes were presented in the above analyzes in polyethylene (PE) films, and thick films damaged relatively less. MPs number was 86,829.11 n/kg in BIOt1 and 134,912.27 n/kg in BIOt2, equivalent to 2.55 and 3.72 times higher than in PEt1 and PEt2, respectively. This was closely associated with PAEs release, as soil PAEs concentration was substantially lower in PEt1 (17.60 g/kg) and PEt2 (21.43 g/kg) than in BIOt1 and BIOt2 (37.12 g/kg and 49.20 g/kg), respectively. Furthermore, maize productivity parameters were negatively correlated with the amount of MPs and PAEs. BIOt2 and PEt1 had the lowest and highest grain yield, respectively. BIO exhibited greater environmental risk and adverse effects on soil and crop productivity than PE film due to physical degradation and release of PAEs. Thickness-wise comparison exhibited that thin film residues had more adverse effect relative to thick film ones.

Microplastics distribution and microbial community characteristics of farmland soil under different mulch methods

The widespread use of plastic film in agricultural production has resulted in the accumulation of large amounts of residual plastic film in the soil, and most of the plastic residuals eventually break up into microplastics (MPs). However, the effects of different film mulching methods on the soil ecosystems are largely unexplored. Therefore, we investigated the MPs distribution and the physicochemical properties and microbial community structure in the farmland soil tillage layer covered with different mulching method of film. The results indicate that the film mulching method had no significant effect on the soil pH and organic matter content, however, the respiration intensity of the soil covered with mulching film (MF) (60.11-84.99 μg/g) and shed film (SF) (56.10-65.68 μg/g) was significantly higher than that covered with shed film & mulching film (SMF) (17.25-39.16 μg/g). The MPs abundance in the soil covered with MF (1367 particles/kg soil) was significantly higher than that covered with SF (800 particles/kg soil) and slightly higher than that with SMF (1000 particles/kg soil). The small-sized (0-0.5 mm) MPs abundance was increased with the tillage layer depth (0-20 cm), while the large-sized (1-5 mm) MPs abundance was the opposite. In addition, in the soil covered with agricultural film, the dominant phylum and genera of the bacteria were Proteobacteria (relative abundance was 64.06 %) and Pseudomonas (13.16 %), respectively. In the soil without agricultural film application as a control treatment, the diversity of the soil bacterial community was higher than that in the soil covered with agricultural film, and the relative abundances of the top 10 genera were all less than 5 %. Overall, this study provides essential information for understanding the effects of different film mulching methods on the agricultural systems. Overall, this study provides essential information for understanding the effects of different film mulching methods on the distribution of MPs and the biogeochemical properties of farmland soils.

Occurrence, source, ecological risk, and mitigation of phthalates (PAEs) in agricultural soils and the environment: A review

The widespread distribution of phthalates (PAEs) in agricultural soils is increasing drastically; however, the environmental occurrence and potential risk of PAEs in agricultural systems remain largely unreviewed. In this study, the occurrence, sources, ecotoxicity, exposure risks, and control measures of PAEs contaminants in agricultural soils are summarized, and it is concluded that PAEs have been widely detected and persist in the soil at concentrations ranging from a few μg/kg to tens of mg/kg, with spatial and vertical variations in China. Agrochemicals and atmospheric deposition have largely contributed to the elevated contamination status of PAEs in soils. In addition, PAEs cause multi-level hazards to soil organisms (survival, oxidative damage, genetic and molecular levels, etc.) and further disrupt the normal ecological functions of soil. The health hazards of PAEs to humans are mainly generated through dietary and non-dietary pathways, and children may be at a higher risk of exposure than adults. Improving the soil microenvironment and promoting biochemical reactions and metabolic processes of PAEs are the main mechanisms for mitigating contamination. Based on these reviews, this study provides a valuable framework for determining future study objectives to reveal environmental risks and reduce the resistance control of PAEs in agricultural soils.

Biodegradation of high di-(2-Ethylhexyl) phthalate (DEHP) concentration by food waste composting and its toxicity assessment using seed germination test

Di-(2-ethylhexyl) phthalate (DEHP), a plasticizer derived from phthalate ester, is used as an additive in industrial products such as plastics, paints, and medical devices. However, DEHP is known as an endocrine-disrupting chemical, causing cancers and adverse effects on human health. This study evaluated DEHP biodegradation efficiency via food waste composting during 35 days of incubation. At high DEHP concentrations (2167 mg kg^-1) in food waste compost mixture, the DEHP biodegradation efficiency was 99% after 35 days. The highest degradation efficiency was recorded at the thermophilic phase (day 3 - day 11) with the biodegradation rate reached 187 mg kg^-1 day^-1. DEHP was metabolized to dibutyl phthalate (DBP) and dimethyl phthalate (DMP) and would be oxidized to benzyl alcohol (BA) and mineralized into CO₂ and water via various metabolisms. Finally, the compost's quality with residual DEHP was evaluated using Brassica chinensis L. seeds via 96 h of germination tests. The compost (at day 35) with a trace amount of DEHP as the end product showed no significant effect on the germination rate of Brassica chinensis L. seeds (88%) compared to that without DEHP (94%), indicating that the compost can be reused as fertilizer in agricultural applications. These results provide an improved understanding of the DEHP biodegradation via food waste composting without bioaugmentation and hence facilitating its green remediation and conversion into value-added products. Nevertheless, further studies are needed on DEHP biodegradation in large-scale food waste composting or industrial applications.

Visualizing the Distribution of Phthalate Esters and Plant Metabolites in Carrot by Matrix-Assisted Laser Desorption/Ionization Imaging Mass Spectrometry

The accumulation of organic pollutants in vegetables is a major global food safety issue. The concentrations of pollutants in vegetables usually differ across different tissues because of different transport and accumulation pathways. However, owing to the limitations of conventional methods, in situ localization of typical organic pollutants such as phthalate esters (PAEs) in plant tissues has not yet been studied. Here, we developed a quick and efficient method for in situ detection and imaging of the spatial distribution of PAEs in a typical root vegetable, carrot, using matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS). The use of a 2,5-dihydroxybenzoic acid matrix with a spray-sublimation coating method led to the successful identification of PAEs ion signals. The IMS results showed that a typical PAE-di-(2-ethylhexyl)phthalate (DEHP) was broadly distributed in the cortex, phloem, and metaxylem, but was barely detectable in the cambium and protoxylem. Interestingly, MALDI-IMS data also revealed for the first time the spatial distribution of sugars and β-carotene in carrots. In summary, the developed method offers a new and practical methodology for the in situ analysis of PAEs and plant metabolites in plant tissues. As a result, it could provide a more intuitive understanding of the movement and transformation of organic pollutants in soil-plant systems.

Plastics derived from disposable greenhouse plastic films and irrigation pipes in agricultural soils: a case study from Turkey

Plastics are ubiquitous. It has been used in human activities, from agriculture to packaging, infrastructure, and health. The wide range of usage makes plastics an omnipresent pollutant in the environment. This study investigated the abundance and type of plastics in agricultural soil in the Adana/Karataş region in Turkey, where disposable low-tunnel greenhouse plastic films and irrigation pipes were in use. For this purpose, 1 kg of soil samples from the top 5 cm (from the surface) was taken from 10 different sampling locations. An average of 16.5 ± 2.4 pcs/kg was found in the soil samples. The highest amount of plastics was seen at the Bahçe-4 location with 39.7 ± 12 pcs/kg and the lowest amount of plastics at the Karataş-1 location with 0.7 ± 0.3 pcs/kg. The average size of plastics was found to be 18.2 ± 1.3 mm. The average size of plastics originating from greenhouse cover was 18.9 ± 1.4 mm, and from disposable irrigation pipes was 12.5 ± 3.5 mm. It was determined that 41.9% of extracted plastics were microplastics, 36.3% were mesoplastics, 16.3% were macroplastics, and 5.6% were megaplastics. Results indicated that residual plastics decreased in the soil where used plastics were removed after usage. As a result, it is worth noting that a significant amount of plastics remain in soil due to plastics being used in agricultural areas.

Phthalates - A family of plasticizers, their health risks, phytotoxic effects, and microbial bioaugmentation approaches

Phthalates are a family of reprotoxicant compounds, predominantly used as a plasticizer to improve the flexibility and longevity of consumable plastic goods. After their use these plastic products find their way to the waste disposal sites where they leach out the hazardous phthalates present within them, into the surrounding environment, contaminating soil, groundwater resources, and the nearby water bodies. Subsequently, phthalates move into the living system through the food chain and exhibit the well-known phenomenon of biological magnification. Phthalates as a primary pollutant have been classified as 1B reprotoxicants and teratogens by different government authorities and they have thus imposed restrictions on their use. Nevertheless, the release of these compounds in the environment is unabated. Bioremediation has been suggested as one of the ways of mitigating this menace, but studies regarding the field applications of phthalate utilizing microbes for this purpose are limited. Through this review, we endeavor to make a deeper understanding of the cause and concern of the problem and to find out a possible solution to it. The review critically emphasizes the various aspects of phthalates toxicity, including their chemical nature, human health risks, phytoaccumulation and entry into the food chain, microbial role in phthalate degradation processes, and future challenges.

Nanoplastic impacts on the foliar uptake, metabolism and phytotoxicity of phthalate esters in corn (Zea mays L.) plants

Nanoplastic pollution in terrestrial plants is of increasing concern for its negative effects on living organisms. However, the impacts of nanoplastics on chemical processes and plant physiology of phthalate esters (PAEs) remain unclear. The present work offers insight into the foliar uptake, metabolism and phytotoxicity of two typical PAEs, namely, di-n-butyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP), in corn (Zea mays L.) seedlings and the effects of amino-functionalized polystyrene nanoplastics (PSNPs-NH₂). The presence of PSNPs-NH₂ increased DBP and DEHP accumulation in the leaves by 1.36 and 1.32 times, respectively. PSNPs-NH₂ also promoted the leaf-to-root translocation of DBP and DEHP, with the translocation factor increasing by approximately 1.05- and 1.16-fold, respectively. Furthermore, the addition of PSNPs-NH₂ significantly enhanced the transformation of PAEs to their primary metabolites, mono-butyl phthalate and mono(2-ethylhexyl) phthalate in corn leaves and roots. The co-presence of PSNPs-NH₂ and PAEs showed stronger impairment of photosystem II efficiency via the downregulation of transporter D1 protein, thus exhibiting a greater inhibitory effect on plant growth. Our findings reveal that nanoplastics promote the foliar uptake and transformation of PAE chemicals in crops and exacerbate their toxicity to crop plants, thereby threatening agricultural safety and human health.

Efficient biodegradation of di-(2-ethylhexyl) phthalate by a novel strain Nocardia asteroides LMB-7 isolated from electronic waste soil

The di-2-ethylhexyl phthalate (DEHP) degrading strain LMB-7 was isolated from electronic waste soil. According to its biophysical/biochemical characteristics and 16S rRNA gene analysis, the strain was identified as Nocardia asteroides. Optimal pH and temperature for DEHP degradation were 8.0 and 30 °C, respectively, and DEHP removal reached 97.11% after cultivation for 24 h at an initial concentration of 400 mg/L. As degradation intermediates, di-butyl phthalates, mono-2-ethylhexyl phthalate and 2-ethylhexanol could be identified, and it could be confirmed that DEHP was completely degraded by strain LMB-7. To our knowledge, this is a new report of DEHP degradation by a strain of Nocardia asteroides, at rates higher than those reported to date. This finding provides a new way for DEHP elimination from environment.

Occurrence and health risk assessment of phthalate esters in tobacco and soils in tobacco-producing areas of Guizhou province, southwest China

Flue-cured tobacco is one of the important sources of national economy in China. However, Phthalic acid esters (PAEs) are ubiquitous contaminants in the cultivation and growth management of flue-cured tobacco, and attracting more and more attention. Here, six priority PAEs were detected in tobacco and soils and their residue characteristics, pollution sources were analyzed, and their exposure risks to the health of farmers were assessed. The concentration of six total PAEs ranged from 0.78 to 4.79 mg/kg in tobacco with the average of 1.75 mg/kg, and 0.84-25.68 mg/kg in soils with the average of 5.40 mg/kg. Di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) had the highest detection frequency (DF = 100%) both in soil and tobacco samples. DEHP was the most abundant of the total PAEs in soil and tobacco samples, with the mean contribution values of 71.0% and 58.8%, respectively. Principal component analysis (PCA) indicates that the major sources of PAEs in the tobacco-soil system were plastic films, fertilizers and pesticides. Health risk assessment suggests that the non-cancer hazard indexes (NCHI) of dimethyl phthalate (DMP), diethyl phthalate (DEP), DBP and di-n-octyl phthalate (DnOP) in all samples for farmers were at acceptable levels (NCHI < 1), and the average carcinogenic hazard indexes (CHI) of butyl benzyl phthalate (BBP) and DEHP for farmers were 3.79 × 10-13 and 8.54 × 10-11 in soils, respectively, 8.23 × 10-13 and 1.95 × 10-11 in tobacco, respectively, which were considered to be very low level (CHI < 10-6). This study provides data on PAEs in tobacco and soils and their health risks which may provide valuable information to aid the management of tobacco cultivation and risk avoidance.

Uptake pathways of phthalates (PAEs) into Chinese flowering cabbage grown in plastic greenhouses and lowering PAE accumulation by spraying PAE-degrading bacterial strain

Uptake pathway and accumulation variation of soil and airborne phthalates (PAEs) in plastic greenhouses by vegetables remains unclear. Here, pot experiments of Chinese flowering cabbage were designed to distinguish root or leaf uptake pathways of PAEs, and investigate the mitigation of spraying PAE-degrading strain in PAE accumulation by vegetables. The results showed that leaves of Chinese flowering cabbage grown in plastic greenhouses absorbed more PAEs from air than those of outside greenhouses. Airborne PAEs were mainly stored in leaf surfaces of vegetables grown inside greenhouse, while PAEs absorbed by roots from soil were translocated and mainly stored in mesophyll, especially in cell walls and organelles. PAE concentrations in mesophyll elevated with increasing soil PAE levels, whereas those in leaf surfaces were not influenced by soil PAE levels. The values of bioconcentration factors for leaves inside greenhouses were significantly (1.39-3.47 fold) higher than those outside. PAE-degrading strain (Rhodococcus pyridinivorans XB) sprayed on leaf surfaces could grow well and Rhodococcus was the dominant genus as confirmed by Illumina high-throughput sequencing. PAE-degrading strain effectively reduced PAEs by 12.9%-34.9% in leaf surface, but not those in vegetables grown in high-PAE soil. This study demonstrated mitigation of spraying PAE-degrading strain in PAE accumulation by vegetable leaves from air of plastic greenhouse.

Environmental fate of dibutylphthalate in agricultural plastics: Photodegradation, migration and ecotoxicological impact on soil

Phthalic acid esters (PAEs) were determined in polyethylene covers used in horticultural production units located at Moreno and La Plata districts (Buenos Aires, Argentina), detecting 0.69-8.75 mg PAEs kg^-1 plastic in greenhouse and tunnel films. The PAEs found were diisobutylphthalate (DIBP), dibutylphthalate (DBP) and diethylhexylphthalate (DEHP). DBP was chosen as a model molecule to carry out the photochemical degradation studies that led to the formation of monobutylphthalate (MBP) and phthalic acid (PA). DBP, MBP and PA migration from plastic covers was studied, finding that while DBP and MBP moved to soil and atmosphere in short times (<48 h), PA remained in the agricultural covers. Further experiments with DBP were made to explore the effect on migration of temperature (20 °C, 50 °C), film thickness (25 μm, 100 μm) and plastic ageing by solarization, observing that temperature increase, film thickness reduction and ageing by solarization favored DBP migration to the environment. DBP and MBP impact on soil were evaluated by avoidance and reproduction tests using Eisenia andrei as bioindicator. Both compounds reduced cocoon viability decreasing the number of juveniles at the lowest concentration assayed (0.1 mg kg^-1 of soil). At higher DBP and MBP concentrations the reproductive parameters (number of total cocoons, hatchability and number of juveniles) also showed alterations compared with the controls. Carboxylesterases (CaE), cholinesterases (ChE) and glutathion-S-transferases (GST) activities were analyzed in E. andrei exposed to DBP; cholinesterases activities were reduced at 1 and 10 mg DBP kg^-1 soil, and glutathione S-transferases activities were increased at 10 mg DBP kg^-1 soil while no effect was observed on carboxylesterases activities. These results emphasize the need to continue studying the impact of PAEs and their photodegradation products on the environment.

Design and Simulation of a Greenhouse FSS Nanofiber Film for Enhancing Agricultural Productivity by Selective Reduction of UV and NIR

A greenhouse covering film is an essential part of any greenhouse. Its function is to filter solar radiation in the ultraviolet (UV) and the near-infrared (NIR) bands while allowing a great amount of photosynthetically active radiation (PAR) to transmit. This paper proposes a design of the greenhouse covering film based on a frequency selective surface (FSS). Aluminum is made into fibers in the nanoscale. They are laid out in an array, in-plane at equidistance from one another. This arrangement induces the wavelength selectivity of light via adjustment to the fiber sizes and spacings. The performance is evaluated by a finite element analysis (FEA) method. The results show less than 26% transmittance of UV and NIR while allowing more than 94% transmittance in the PAR regime.

DEHP-induced mitophagy and mitochondrial damage in the heart are associated with dysregulated mitochondrial biogenesis

Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer widely used in agricultural and industrial plastic products. Many researchers have demonstrated that DEHP can cause varying degrees of harm to the heart. This research investigated the mechanism by which DEHP causes heart damage in quail. The quail were treated with DEHP (250 mg/kg BW/day, 500 mg/kg BW/day or 750 mg/kg BW/day) for 45 days. The present study suggested that DEHP could cause varying levels of heart damage, including disordered myocardial fiber arrangements, myocardial fiber breakage and myocardial cell swelling. The results showed that DEHP induced mitochondrial damage, such as cavitation lesions and mitochondrial crest breakage. DEHP damaged mitochondria and inhibited nuclear respiratory factor 1 (Nrf1)-mediated mitochondrial biogenesis, which led to mitochondrial damage. DEHP caused oxidative stress in the heart and activated the defense mechanism of the nuclear factor red blood cell 2 related factor 2 (Nrf2) system. DEHP-induced mitophagy was related to a decline in mitochondrial biogenesis and disordered mitochondrial dynamics. The data indicated that DEHP exposure damaged cardiac mitochondria and caused mitophagy and cardiotoxicity. Of note, this study showed that DEHP-induced mitophagy and mitochondrial damage are associated with the dysregulation of mitochondrial biogenesis.

Tissue distribution of phthalates in celery under different cultivation patterns and associated dietary exposure

To investigate tissue distribution, spatial difference, temperature variation, and potential health risks of PAEs in vegetables, celery was used as a model plant. Celery samples were collected from open fields and greenhouses from two provinces in China over four seasons. Celery tissues were analyzed for 16 PAE compounds by gas chromatography-tandem mass spectrometry. The total content of PAEs was 89.0-1130.3 μg kg^-1 dry weight (dw) in stems and 155.0-2730.8 μg kg^-1 dw in leaves. Concentrations of PAEs in celeries showed notable spatial differences (P < 0.05), and the levels in samples from open fields were lower than those in samples from plastic greenhouses. In celeries from greenhouses, higher PAE concentrations were observed for plants grown at high temperatures than in plants grown at low temperatures. Discrepancies in tissue distribution indicated different uptake pathways of PAE contaminants. Risk assessments to humans found that both carcinogenic risks and non-carcinogenic risks of PAEs via celery consumption were at an acceptable level. Further research should consider other exposure pathways of PAEs and pay special attention to reducing PAE contents in vegetables.

Evaluation of the Removal of Selected Phthalic Acid Esters (PAEs) in Municipal Wastewater Treatment Plants Supported by Constructed Wetlands

Phthalic acid esters (PAEs) have a negative impact on living organisms in the environment, therefore, are among the group of Endocrine Disrupting Compounds (ECDs). Unfortunately, conventional methods used in municipal wastewater treatment plants (MWWTPs) are not designed to eliminate PAEs. For this reason, the development of cheap and simple but very effective techniques for the removal of such residues from wastewater is crucial. The main aim of this study was the evaluation of the removal of six selected PAEs: diethyl phthalate (DEP), di-n-octyl phthalate (DOP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), bis(2-ethylhexyl) phthalate (DEHP) and dimethyl phthalate (DMP), in real MWWTPs supported by constructed wetlands (MWWTP-CW system). For the first time, the possibility of using three new plants for this purpose, Cyperus papyrus (papyrus), Lysimachia nemorum (yellow pimpernel) and Euonymus europaeus (European spindle), has been presented. For determining the target PAEs in wastewater samples, a method of SPE (Solid-Phase Extraction)-GC-MS(SIM) was developed and validated, and for plant materials, a method of UAE (Ultrasound-Assisted Extraction)-SPE-GC-MS(SIM) was proposed. The obtained data showed that the application of the MWWTP-CW system allows a significant increase in the removal of DEP, DBP, BBP and DEHP from the wastewater stream. Euonymus europaeus was the most effective among the tested plant species for the uptake of analytes (8938 ng × g^-1 dry weight), thus, this plant was found to be optimal for supporting conventional MWWTPs.

Agricultural Plastic Pollution in China: Generation of Plastic Debris and Emission of Phthalic Acid Esters from Agricultural Films

Agricultural plastic films have been proven highly advantageous, but they also cause pollution of plastic debris and associated chemicals. Phthalates (phthalic acid esters, PAEs), an important additive of agricultural films, can be released and contaminate the environment. Here, we analyzed the agricultural plastic usage and assessed plastic debris in China and developed a method to estimate PAE emissions from agricultural films. Additionally, the environmental fate of PAEs was evaluated using a fugacity-based multimedia model. The agricultural plastic film usage in China in 2017 was 2,528,600 tons. After agricultural film recycling and water erosion, the plastic debris amount was estimated as 465,016 tons. The water erosion process carried 4329 tons of plastic debris into the aquatic environment. During its lifetime, the agricultural film released a total of 91.5 tons of two typical types of PAEs. PAEs from the mulching film would mostly be removed through degradation, while those from the greenhouse film accumulate in vegetables. Populated regions exhibited more serious PAE pollution in vegetables but with no immediate health risks. The model was well evaluated using comparable measured concentrations and uncertainty analysis based on the Monte Carlo method. The findings from this study demonstrate the serious agricultural plastic pollution problem and associated PAE contamination in China.

The effects of phthalate ester exposure on human health: A review

Phthalate esters (PAEs) are one of the most widely used plasticizers in polymer products and humans are increasingly exposed to them. The constant exposure to PAEs-contained products has raised some concerns against human health. Thus, the impacts of PAEs and their metabolites on human health require a comprehensive study for a better understanding of the associated risks. Here, we attempt to review eight main health effects of PAE exposure according to the most up-to-date studies. We found that epidemiological studies demonstrated a consistent association between PAE exposure (especially DEHP and its metabolites) and a decrease in sperm quality in males and symptom development of ADHD in children. Overall, we found insufficient evidence and lack of consistency of the association between PAE exposure and cardiovascular diseases (hypertension, atherosclerosis, and CHD), thyroid diseases, respiratory diseases, diabetes, obesity, kidney diseases, intelligence performance in children, and other reproductive system-related diseases (anogenital distance, girl precocious puberty, and endometriosis). Future studies (longitudinal and follow-up investigations) need to thoroughly perform in large-scale populations to yield more consistent and powerful results and increase the precision of the association as well as enhance the overall understanding of potential human health risks of PAEs in long-term exposure.

Risk Assessment of Agricultural Plastic Films Based on Release Kinetics of Phthalate Acid Esters

Plastic films have become an integral part of fruit and vegetable production systems, but their release of phthalate acid esters (PAEs) is a threat to human health. The release kinetics of PAEs and measures of risk are still not well understood. We investigated 50 agricultural films, with concentrations ranging from 2.59 to 282,000 mg kg^-1. The seven commercially available film types included were polyvinylchloride (PVC), metallocene polyethylene (mPE), ethylene vinyl acetate (EVA), polyolefin (PO), and three mulch films. Bis(2-ethylhexyl) phthalate (DEHP) was detected in most of films, and its release fitted well into the first-order kinetic model. The release rate of DEHP was negatively related to the film thickness. The potential carcinogenic risks of DEHP in the air of six kinds of plastic greenhouses to human health were estimated. We found that the carcinogenic risks associated with PVC and mPE greenhouse films warrant greater attention. Though EVA, PO greenhouse, and mulch films were lower risk, we advise keeping plastic greenhouses well ventilated during the first month of use to reduce direct human exposure to volatile PAEs.

Testing Biodegradable Films as Alternatives to Plastic-Film Mulching for Enhancing the Yield and Economic Benefits of Processed Tomato in Xinjiang Region

The extensive application of plastic-film mulching (PFM) has brought a series of environmental pollution due to the lack of awareness of plastic-film rational use and absence of plastic residues recycling in China. In addition, the use of degradable film instead of common polyethylene plastic film (PE film) can effectively alleviate this situation. The substitution of PE film with biodegradable film in the agricultural production of processed tomato in Xinjiang region was investigated in this study. Using bare soil as the control, we compared the effects of PE film and biodegradable film mulching on crop growth, yield, and economic benefits in processed tomato. The results indicated that: (1) Biodegradable film with a thickness of about 8 μm can meet the mechanical operation requirements, and the effect of biodegradable film mulching was completely consistent with that of PE film; (2) Four kinds of biodegradable film can meet the requirements of processed tomato growth and development, although slightly different from PE film in increasing temperature and water retention; (3) Plastic-film planting can ensure a net profit of 1.14–1.64 ten thousand CNY per hectare under the current production conditions and mode of Xinjiang region, and biodegradable film planting was observed to be essentially equal to those of PE film; (4) Nearly 50%–70% of the biodegradable film was ruptured and degraded during processed tomato harvesting, which avoided the occurrence of the winch of the plastic-film winding harvester and improves the efficiency and commodity rate of the processed tomato harvest operation. As the biodegradable film mulching causes no residual pollution, it is accepted to be an alternative to plastic-film mulching for agricultural applications and supports the sustainable development of agroecosystems in Xinjiang region.

Single-use plastics: Production, usage, disposal, and adverse impacts

Single-use plastics (SUPs), invented for the modern "throwaway society," are intended to be used only once. They are being increasingly produced and used globally, most notably as packaging or consumables, such as SUP shopping bags or disposable tableware. We discuss how most SUPs are landfilled or incinerated, which causes pollution, consumes valuable land, and squanders limited natural resources. Only relatively small amounts are currently recycled, a hindrance to the concept of a circular economy. Moreover, SUP litter aggregation in the natural environment is a major concern. This article briefly reviews SUP contamination in various environmental media including soil, rivers, lakes and oceans around the world. In the face of mounting evidence regarding the threat posed to plant growth, soil invertebrates and other land animals, (sea) birds, and marine ecosystems, there is a growing push to minimize SUPs. Regulatory tools and voluntary actions to reduce SUP usage have been put forward, with some suggestions for minimizing SUP waste.

Pollution characteristics of phthalate acid esters in agricultural soil of Yinchuan, northwest China, and health risk assessment

Eighty-nine agricultural surface soil samples from different types of land of Yinchuan were collected and detected for sixteen phthalate acid ester (PAE) compounds; the pollution characteristics and pollution distribution were analyzed. In addition, the potential health risk exposures to local resident of six priority control phthalates by the US EPA were assessed. All soil samples were contaminated with PAEs, the total concentrations of Σ₁₆PAEs were between 0.391 and 11.924 mg kg^-1, and the mean concentrations were 4.427 mg kg^-1 in soil. Among the sixteen PAE congeners, DMP was the most abundant component, which accounted for average 44.64% of the total PAEs, then DnBP and DEHP, which accounted for the average contribution rate, were 21.25% and 23.34%, respectively, and DpHP was not detected in all soil samples. Risk assessment indicated that the risk of non-carcinogenesis in this study was within the acceptable range; however, the carcinogenic risk of DEHP through intake dietary significantly exceeded the carcinogenic level recommended by the US EPA (1 × 10^-6) and therefore presented a potential carcinogenic risk. More considerable attention should be given to the PAEs contamination status in soils and potential effects on local resident health.

Prevalent phthalates in air-soil-vegetable systems of plastic greenhouses in a subtropical city and health risk assessments

Wide use of plastic greenhouses for vegetable production increases human exposure to phthalate (PAEs) through vegetable intake. However, little information is available about distribution of PAEs in air-soil-vegetable systems of plastic greenhouses and PAE estrogenic effects. This study was designed to investigate PAE distributions and corresponding health risk in plastic greenhouses in Guangzhou, a subtropical city in South China. PAEs were prevalent in plastic greenhouses, with sum concentrations of 16 PAE compounds (∑16PAEs) up to 5.76 mg/kg in soils, 5.27 mg/kg in vegetables and 4393 ng/m³ in air. Di (2-ethylhexyl) phthalate, di-isobutyl phthalate, and dibutyl phthalate were predominant compounds. Average concentrations and bioconcentration factor of ∑16PAEs and the predominant PAE compounds in vegetables of greenhouses were higher than those of open fields. Plastic greenhouses exhibited significantly higher air PAE levels than those of open fields due to higher indoor temperature, which enhanced PAE accumulation by vegetables. Both carcinogenic and non-carcinogenic risks of PAEs via dietary and non-dietary exposures for farmers decreased with an order of vegetable > air > soil. Consumption of vegetables from greenhouses resulted in significantly higher estrogenic effects compared to those from open field cultivation. This study emphasizes highly potential health risks of PAEs in air-soil-vegetable systems of plastic greenhouses.

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

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

Metabolism of mono-(2-ethylhexyl) phthalate in Arabidopsis thaliana: Exploration of metabolic pathways by deuterium labeling

Mono-(2-ethylhexyl) phthalate (MEHP) is the primary monoester transformation product of the commonly used plasticizer, di-2-ethylhexyl phthalate (DEHP), and has been frequently detected in various environmental compartments (e.g., soil, biosolids, plants). Plants growing in contaminated soils can take up MEHP, and consumption of the contaminated plants may result in unintended exposure for humans and other organisms. The metabolism of MEHP in plants is poorly understood, but critical for evaluating the potential human and environmental health risks. The present study represents the first attempt to explore the metabolic fate of MEHP in plants. We used Arabidopsis thaliana cells as a plant model and explored metabolic pathways of MEHP using deuterium stable isotope labelling (SIL) coupled with time-of-flight high resolution mass spectrometer (TOF-HRMS). A. thaliana rapidly took up MEHP from the culture medium and mediated extensive metabolism of MEHP. Combining SIL with TOF-HRMS analysis was proved as a powerful method for identification of unknown MEHP metabolites. Four phase Ⅰ and three phase Ⅱ metabolites were confirmed or tentatively identified. Based on the detected transformation products, hydroxylation, oxidation, and malonylation are proposed as the potential MEHP metabolism pathways. In cells, the maximum fraction of each transformation product accounted for 2.8-56.5% of the total amount of metabolites during the incubation. For individual metabolites, up to 2.9-100% was found in the culture medium, suggesting plant excretion. The results in the cell culture experiments were further confirmed in cabbage and A. thaliana seedlings. The findings suggest active metabolism of MEHP in plants and highlight the need to include metabolites in refining environmental risk assessment of plasticizers in the agro-food systems.

Presence, distribution and risk assessment of phthalic acid esters (PAEs) in suburban plastic film pepper-growing greenhouses with different service life

The widespread usage of plastic film increased the content of phthalic acid esters (PAEs) in the environment, causing PAE residue in vegetables and subsequently increasing health risks to humans when consuming them. In this work, the presence, distribution and risk assessment of 15 PAEs in soils and peppers from suburban plastic film pepper-growing greenhouses were investigated. The total PAE contents in soil and pepper samples ranged from 320.1 to 971.2 μg/kg (586.3 μg/kg on average) and from 196.6 to 304.2 μg/kg (245.4 μg/kg on average), respectively. Di (2-ethyl)hexyl, dibutyl and diisobutyl phthalates (DEHP, DnBP and DiBP, respectively) were the most abundant in both soil and pepper samples. Specifically, DEHP showed the highest content in soils, while the DnBP content was the highest in peppers. The total PAE content in soils from pepper-greenhouses was much lower than in the agricultural soils mulched with plastic films, but significantly higher than in the agricultural soils from open uncovered fields. The total PAE content in peppers decreased as the service life of plastic film greenhouses increased. Correlation analysis suggested that the difference in distribution and accumulation behaviors of individual PAEs in greenhouse systems was correlated with their physicochemical properties. The non-cancer and carcinogenic risks of priority PAEs show low risks of PAEs detected in pepper and soil samples from the suburban plastic film greenhouses to human health.

Plastic pollution in croplands threatens long-term food security

Plastic pollution is a global concern given its prevalence in aquatic and terrestrial ecosystems. Studies have been conducted on the distribution and impact of plastic pollution in marine ecosystems, but little is known on terrestrial ecosystems. Plastic mulch has been widely used to increase crop yields worldwide, yet the impact of plastic residues in cropland soils to soil health and crop production in the long term remained unclear. In this paper, using a global meta-analysis, we found that the use of plastic mulch can indeed increase crop yields on average by 25%-42% in the immediate season due to the increase of soil temperature (+8%) and moisture (+17%). However, the unabated accumulation of film residues in the field negatively impacts its physicochemical properties linked to healthy soil and threatens food production in the long term. It has multiple negative impacts on plant growth including crop yield (at the mean rate of -3% for every additional 100 kg/ha of film residue), plant height (-2%) and root weight (-5%), and soil properties including soil water evaporation capacity (-2%), soil water infiltration rate (-8%), soil organic matter (-0.8%) and soil available phosphorus (-5%) based on meta-regression. Using a nationwide field survey of China, the largest user of plastic mulch worldwide, we found that plastic residue accumulation in cropland soils has reached 550,800 tonnes, with an estimated 6%-10% reduction in cotton yield in some polluted sites based on current level of plastic residue content. Immediate actions should be taken to ensure the recovery of plastic film mulch and limit further increase in film residue loading to maintain the sustainability of these croplands.

Accumulation and transport patterns of six phthalic acid esters (PAEs) in two leafy vegetables under hydroponic conditions

In this study, we investigated the accumulation and transport patterns of six phthalic acid esters (PAEs) in two leafy vegetables under hydroponic conditions. The tested PAEs included dibutyl phthalate (DBP), diethyl phthalate (DEP), diallyl phthalate (DAP), diisobutyl phthalate (DIBP), dimethyl phthalate (DMP) and benzyl butyl phthalate (BBP), and the tested vegetables included Gaogengbai and Ziyoucai. The results revealed that the six PAEs were taken up by vegetables from the solution, although their accumulation and distribution varied among PAEs. The ability of concentrating PAEs into the roots followed the order of BBP > DBP > DIBP > DAP > DEP > DMP, whereas the ability of concentrating PAEs in plant shoots had the opposite order. By analysing the fractionation of the six PAEs in vegetable roots, DMP had the largest proportion in terms of apoplastic movement, while BBP had the largest proportion in terms of symplastic movement. Correlation analyses revealed that the differences among the accumulation and distribution behaviours of the six PAEs in plant tissues were not only related to their physicochemical parameters, such as alkyl chain length and the octanol/water partition coefficient (logK_ow), but also related to the proportion of apoplastic and symplastic movement in the plant roots. In addition, PAEs were more readily accumulated in the Gaogengbai roots than in the Ziyoucai roots; however, the opposite trend was observed for the shoots.

Phthalate esters (PAEs) in soil and vegetables in solar greenhouses irrigated with reclaimed water

Phthalate esters (PAEs) in environments have become a public concern due to their harmful impacts on human and environments, and waste/reclaimed water irrigation maybe one of their sources in agricultural soil. A field experiment was setup to analyze the impacts of reclaimed water irrigation on levels of PAEs in vegetables and topsoil in solar greenhouse on the North China Plain during 2015 and 2016. There were 6 varieties of vegetables. For each variety, there were three irrigation treatments, including groundwater irrigation, reclaimed water irrigation, and alternative irrigation with groundwater and reclaimed water (1:1, v/v). The results show that the levels of the 6 PAEs in soil and vegetables varied between 0.73 and 9.48 mg/kg and 1.89 and 6.35 mg/kg, respectively. There were no significant differences for PAE concentrations among these different treatments at each vegetable harvest (p > 0.05). For both soil and vegetable samples, Di-n-butyl phthalate (DnBP) and Di (2-ethylhexyl) phthalate (DEHP) were the most dominant PAEs, with contents of 0.39-4.43 mg/kg and 0.25-6.31 mg/kg, respectively, contributing12.5-74.60% and 21.24-76.48% of the total 6 PAEs, respectively. The contents of DnBP and dimethyl phthalate (DMP) in topsoil were higher than the suggested allowable values, while the concentration of each individual PAE in topsoil was lower than the suggested cleanup objectives. The levels of 6 PAEs, DEHP, and DnBP in vegetables were below the reference doses. The yields of eggplant, cauliflower, bean, cabbage, cucumber, and carrot were 64.4-67.0 t/ha, 10.9-13.0 t/ha, 12.3-15.1 t/ha, 17.3-17.5 t/ha, 43.9-44.5 t/ha, and 19.0-22.9 t/ha, respectively, and no significant differences were found among these different treatments for each kind of vegetable. The bioaccumulation factors (BCFs) of 6 PAEs in vegetable samples were 0.43-5.79 and the corresponding values for each PAE were 0.00-27.32, respectively. The BCFs of butyl benzyl phthalate were the greatest (with a mean of 9.28), followed by DEHP (with a mean of 3.03) and DMP (with a mean of 1.90). In one word, the reclaimed water in this study did not affect the vegetable yields obviously. PAE levels in soil and vegetables irrigated with reclaimed water were in the acceptable range. Considering the difference of reclaimed water quality of Sewage Treatment Plants in different areas, so more reclaimed water from different areas is needed to assess the impacts of reclaimed water irrigation on PAE contamination in soil and vegetables.

Effects of biodegradable plastic film mulching on soil microbial communities in two agroecosystems

Plastic mulch films are used globally in crop production but incur considerable disposal and environmental pollution issues. Biodegradable plastic mulch films (BDMs), an alternative to polyethylene (PE)-based films, are designed to be tilled into the soil where they are expected to be mineralized to carbon dioxide, water and microbial biomass. However, insufficient research regarding the impacts of repeated soil incorporation of BDMs on soil microbial communities has partly contributed to limited adoption of BDMs. In this study, we evaluated the effects of BDM incorporation on soil microbial community structure and function over two years in two geographical locations: Knoxville, TN, and in Mount Vernon, WA, USA. Treatments included four plastic BDMs (three commercially available and one experimental film), a biodegradable cellulose paper mulch, a non-biodegradable PE mulch and a no mulch plot. Bacterial community structure determined using 16S rRNA gene amplicon sequencing revealed significant differences by location and season. Differences in bacterial communities by mulch treatment were not significant for any season in either location, except for Fall 2015 in WA where differences were observed between BDMs and no-mulch plots. Extracellular enzyme assays were used to characterize communities functionally, revealing significant differences by location and sampling season in both TN and WA but minimal differences between BDMs and PE treatments. Overall, BDMs had comparable influences on soil microbial communities to PE mulch films.

Aryl Hydrocarbon Receptor as a Target for Lycopene Preventing DEHP-Induced Spermatogenic Disorders

Di(2-ethylhexyl)phthalate (DEHP) is widely used as a plasticizer to improve product flexibility and workability. Lycopene (LYC) is a natural compound and has promising preventive potentials, especially antireproductive toxicity, but the specific underlying mechanism is yet to be fully defined. Our study investigated the effect of LYC on DEHP-induced spermatogenesis disorders. Male ICR mice were treated with DEHP (500 or 1000 mg/kg BW/day) and/or LYC (5 mg/kg BW/day) for 28 days. Our results indicated that LYC could relieve the DEHP-induced injury of seminiferous tubules and spermatogenic cells, swelling of endoplasmic reticulum (ER), and an increase of mitochondria. LYC prevented increased levels of nuclear damage to DNA and the deformity rate and decreased values of sperm motility, number, and density. Moreover, LYC treatment decreased DEHP-induced nuclear accumulation of aryl hydrocarbon receptor (AHR) and AHR nuclear translocator (ARNT), and the expressions of their downstream target genes such as cytochrome P450-dependent monooxygenases (CYP) 1A1, 1A2, and 1B1 were markedly reduced to normal in the LYC treatment group. Our study showed that LYC can prevent DEHP-induced spermatogenic disorders via an AHR/ARNT signaling system. This study provided new evidence of AHR as a target for LYC, which can prevent DEHP-induced toxicity.

Lycopene Prevents DEHP-Induced Leydig Cell Damage with the Nrf2 Antioxidant Signaling Pathway in Mice

As a plasticizer, di(2-ethylhexyl) phthalate (DEHP) is the most usually used phthalate. Leydig cell is a male-specific cell, which plays a principal role in spermatogenesis and masculinization by the androgens of synthesis and secretion. Numerous researchers have indicated that DEHP can result in testicular toxicity by inducing oxidative stress. Lycopene (LYC) is a possible treatment option for male infertility due to its natural antioxidant properties. Our study was aimed to investigate whether LYC could rescue DEHP-induced Leydig cell damage. The mice were treated with DEHP (500 mg/kg BW/day or 1000 mg/kg BW/day) and/or LYC (5 mg/kg BW/day) for 28 days. We found that LYC attenuated DEHP-induced Leydig cell damage. Moreover, the protective role of LYC was verified by the histopathological and ultrastructural analysis of the Leydig cell. LYC suppressed oxidative stress that was induced by DEHP. In the Leydig cell, the expressions of the nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target genes were improved through LYC-mediated protection in DEHP-induced Leydig cell damage. Our findings indicated that LYC could increase the antioxidant capacity via mediating Nrf2 signaling pathway, thereby attenuating DEHP-induced Leydig cell damage.

Oral intake exposure to phthalates in vegetables produced in plastic greenhouses and its health burden in Shaanxi province, China

Phthalate exposure from Vegetables grown in Plastic Greenhouses (VPGs) represents an important source of total daily phthalate exposure in China. However, quantified health risks of phthalates attributable to VPG intake have not been documented. To fill this gap, this study estimates phthalate exposure from VPG intake in western China and calculates the first assessment of the disease burden associated with phthalate exposure from VPG intake in China based on a simple steady-state exposure model and a linear dose-response function between human bio-monitoring phthalates and Type 2 Diabetes (T2D) prevalence. What we present in this paper is a problem identification and screening level risk assessment. We chose Shaanxi province as the research field site due to its large contribution to the total vegetable yield and consumption in western China. Phthalate concentration in VPG samples, phthalate exposure levels from VPG intake, and the T2D burden caused by phthalate attributable to VPG intake for adults were measured or calculated. Di-2-ethylhexyl phthalate (DEHP) was found to represent over 55% of the total phthalate concentration in VPGs, followed by di-n-butyl phthalate (DnBP) and di-isobutyl phthalate (DiBP). Phthalate exposure from VPG intake for urban adults was higher than the level for rural adults. The share of DEHP exposure from VPG intake to urinary total DEHP metabolites were nearly 8% and 15%, and the share of DnBP exposure caused by VPG intake to total daily DnBP metabolites were nearly 4% and 7%, for rural and urban adult populations in Shaanxi, respectively. The adult population with T2D attributable to phthalate exposure from VPG intake was 2561, nearly 6.4% to the T2D burden attributable to total phthalate exposure, and 0.4% to the total adult population with T2D in Shaanxi. The authors recommend policy interventions to protect populations from future risk of phthalate exposure.

Metabolism and distribution of dibutyl phthalate in wheat grown on different soil types

Herein, we investigated the distribution of dibutyl phthalate (DBP) in the tissues of wheat grown on DBP-contaminated soils and determined the activity of detoxifying enzymes [cytochrome P450 (P450) and glutathione S-transferase (GST)] in these tissues at different growth stages of wheat. The content of DBP in wheat grown on all soil types increased with increasing DBP stress concentration, and the DBP content of each tissue decreased as wheat growth progressed. Under the same conditions, the DBP content of roots exceeded that of leaves and stems, and the DBP content of all tissues decreased in the order of brown soil > fluvo-aquic soil > cinnamon soil. The decrease of DBP content with growth and the content of mono-n-butyl dicarboxylate (MBP, main metabolite of DBP) followed the order of cinnamon soil > fluvo-aquic soil > brown soil; the latter parameter initially increased and then decreased as growth progressed. The changes in P450 content and GST activities in wheat tissues were highly consistent with the corresponding changes in DBP and MBP content, except for the DBP stress level of 40 mg kg^-1 at the seedling stage. Based on the obtained results, it was speculated that P450 and GST were strongly involved in the metabolism of DBP in wheat: oxygen atoms were inserted into the aldehyde C-H bond of the species generated after hydrolysis of ester groups under the action of P450 to achieve hydrocarbon hydroxylation under mild conditions and generate MBP.

Populus alba dioctyl phthalate uptake from contaminated water

Phthalates are micro-pollutants of great concern due to their negative effects on ecosystem functioning and human health. Thanks to its capability in uptake and accumulation of organic pollutants, Populus alba L. "Villafranca" clone could be a good candidate for reducing the impacts derived by the persistence of such compounds in the environment. We investigated plant response and uptake of dioctyl phthalate (DOP) by poplar, grown in hydroponics condition, for 21 days with 0, 40, and 400 μg L^-1 of d₄-DOP. Treated plants, after 21 days of 400 μg L^-1 d₄-DOP, showed an increase in root dry biomass (+ 29%) at the expense of aerial parts (- 8%) compared with control. The root development could be sustained by the increase of Mg uptake by poplar. LC-MS/MS analysis demonstrated the uptake and accumulation in roots of d₄-DOP starting from day one (3.5 ± 3.29 and 7.1 ± 3.28 in 40 and 400 μg L^-1 d₄-DOP respectively), despite volatilization of d₄-DOP was observed from nutritive solution. The chemical interaction between d₄-DOP and Zn occurred in roots of plants treated with the high d₄-DOP concentration, without limiting the Zn concentration in leaves. Results confirm the high tolerance of "Villafranca" clone to xenobiotic and suggest the poplar capability in d₄-DOP uptake and accumulation at root level.

The drivers of bacterial community underlying biogeographical pattern in Mollisol area of China

In order to better understand the composition and driving factors of the bacterial community in Mollisols, we selected 9 representative facility agricultural lands in Mollisol area of China for sampling, and described it on a larger spatial scale. Soil bacterial community structure in these 9 regions (determined by high-throughput sequencing analysis) showed significant differences at the genus level. The correlation between bacterial community composition and soil properties, contaminants and geographical latitude showed that the diversity of bacterial community was still strongly correlated with pH and SOM under the influence of phthalates (P < 0.05). Principal component Analysis (PCA) showed that soil properties (i.e. pH, organic matter, stacking density, the content of nitrogen, potassium, phosphorus) and PAEs level rather than geographic latitude were main drivers of differences in bacterial community structure. These factors account for 73.04% of the total variation of the bacterial community. Among them, PAEs act as a typical pollutant is the main factor driving the composition of bacterial community in facility agriculture Mollisols. This shows that PAEs is a potential pollution risk factor, which has important guiding significance for the sustainable and healthy development of agriculture in Mollisol area.

Biodegradation of Structurally Diverse Phthalate Esters by a Newly Identified Esterase with Catalytic Activity toward Di(2-ethylhexyl) Phthalate

Herein, we report a double enzyme system to degrade 12 phthalate esters (PAEs), particularly bulky PAEs, such as the widely used bis(2-ethylhexyl) phthalate (DEHP), in a one-pot cascade process. A PAE-degrading bacterium, Gordonia sp. strain 5F, was isolated from soil polluted with plastic waste. From this strain, a novel esterase (GoEst15) and a mono(2-ethylhexyl) phthalate hydrolase (GoEstM1) were identified by homology-based cloning. GoEst15 showed broad substrate specificity, hydrolyzing DEHP and 10 other PAEs to monoalkyl phthalates, which were further degraded by GoEstM1 to phthalic acid. GoEst15 and GoEstM1 were heterologously coexpressed in Escherichia coli BL21 (DE3), which could then completely degrade 12 PAEs (5 mM), within 1 and 24 h for small and bulky substrates, respectively. To our knowledge, GoEst15 is the first DEHP hydrolase with a known protein sequence, which will enable protein engineering to enhance its catalytic performance in the future.

Di-(2-ethylhexyl) phthalate (DEHP)-induced hepatotoxicity in quail (Coturnix japonica) via suppression of the heat shock response

Di-(2-ethylhexyl) phthalate (DEHP) is a widespread environmental toxicant that severely impacts agricultural production and animal and human health. Nevertheless, DEHP-induced hepatotoxicity at the molecular level in quail remains unexplored. The heat shock response (HSR), involving heat shock proteins (HSPs) and heat shock transcription factors (HSFs), is a highly conserved molecular response that is triggered by stressors, especially exposure to toxicants. To explore the DEHP-induced hepatotoxicity that occurs via regulation of HSR in birds, female quail were dosed with DEHP by oral gavage (0, 250, 500 and 1000 mg/kg) for 45 days. Based on histopathological analysis, the livers of the DEHP-treated groups exhibited structural alterations of hepatocytes, including mitochondrial swelling, derangement of hepatic plates, inflammatory cell infiltration and adipose degeneration. Ultrastructural evaluation of the livers of DEHP-treated quail revealed swollen mitochondria, partial disappearance of mitochondrial membranes and cristae, nuclear chromatin margination and nuclear condensation. The expression of HSF1 and HSF3 significantly decreased after DEHP exposure. The levels of HSPs (HSP10, HSP25, HSP27, HSP40, HSP47, HSP60, HSP70 and HSP90) were significantly downregulated in the livers of DEHP-treated quail. In this study, we concluded that DEHP exposure resulted in liver function damage and hepatotoxicity by reducing the expression of HSFs and HSPs in quail liver, which inhibited the protective effect of the HSR signaling pathway.

Plastic film mulching increased the accumulation and human health risks of phthalate esters in wheat grains

Plastic film mulching is a common practice to increase crop yield in dryland, while the wide use of plastic film has resulted in ubiquitous phthalate esters (PAEs) releasing into the soil. PAEs in soil could be taken up and accumulated by dietary intake of food crops such as wheat, thus imposing health risks to residents. In the present study, samples from a long-term location-fixed field experiment were examined to clarify the accumulation of PAEs in soil and wheat, and to assess the human health risks from PAEs via dietary intake of wheat grain under plastic film mulching cultivation in dryland. Results showed that concentrations of PAEs in grains from mulching plots ranged from 4.1 to 12.6 mg kg^-1, which were significantly higher than those in the control group. There was a positive correlation for the PAE concentrations between wheat grains and field soils. Concentrations of PAEs in the soil were in the range of 1.8-3.5 mg kg^-1 for the mulching treatment, and 0.9-2.7 mg kg^-1 for the control group. Di-n-butyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) were detected in all soil and grain samples, and DEHP was found to be the dominant PAE compound in grains. Based on DEHP concentrations in wheat grains, the values of carcinogenic risk for adults were higher than the recommended value 10^-4. Results indicated that wheat grains from film mulching plots posed a considerable non-carcinogenic risk to residents, with children being the most sensitive resident group. Findings of this work call the attention to the potential pollution of grain crops growing in the plastic film mulching crop production systems.

Soil ecotoxicity study of DEHP with respect to multiple soil species

Di (2-ethylhexyl) phthalate or DEHP is classified as an endocrine-disrupting chemical. It is used as a plasticizer and pesticide additive. Moreover, it has a half-life of about 150-300 days. Thus, it is present in the soil environment and soil risk assessments for DEHP are needed. However, a number of studies have focused on the effects of DEHP in a single soil species. In this study, we conducted acute and chronic toxicity testing for DEHP using varied soil species, including plants, earthworms, soil algae, Collembola, and soil nematodes. In the plant toxicity test, no effect was observed at very high concentration except at some endpoints, and no effect was observed in the earthworm toxicity test. However, there were adverse effects on soil algae, Collembola, and nematodes. Notably, in the Collembola assays, the survival of adults decreased significantly at very high concentrations, whereas reproduction was hindered at low concentrations. Similar inhibition of reproduction was noted in the soil nematode assay. This suggests that DEHP has a greater influence on fertility than survival in the adult test species. However, besides hindered reproduction, no effect was observed on soil species at environmentally relevant concentrations.

The phyllosphere indigenous microbiota of Brassica campestris L. change its diversity in responding to di-n-butyl phthalate pollution

In this study, the effects of di-n-butyl phthalate (DBP) on the phyllosphere bacterial community of field mustard (Brassica campestris L.) at the five-leaf stage were investigated. The indigenous alpha-diversity of the phyllosphere bacteria was altered after spraying with different concentrations of DBP. Shannon diversity indices were significantly changed on day 5 after treatment at DBP concentrations > 400 mg L^-1 (P > 0.05). Nevertheless, the difference between treatment and control was not significant on day 9 after DBP treatment (P > 0.05). Exposure to DBP resulted in a decrease in Proteobacteria and Firmicutes, and an increase in Actinobacteria at all sampling intervals. These changes included significant increases in the relative abundance of Paracoccus and Rhodococcus, and significant decreases in that of Pseudomonas, Exiguobacterium, an unclassified genus of Pseudomonadaceae, and an unclassified genus of Enterobacteriaceae. This study provides new evidence for the possibility of using phyllosphere microbiota to remediate DBP contamination.

Physiological responses of wheat planted in fluvo-aquic soils to di (2-ethylhexyl) and di-n-butyl phthalates

Di (2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) are important pollutants that contaminate agricultural soils. We determined the effects of di (2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) on the production of reactive oxygen species, photosynthesis, and activity of antioxidant enzymes in wheat planted in fluvo-aquic soils. DBP- and DEHP-induced oxidative stress decreased the values of the photosynthetic/fluorescence parameters (except for intercellular carbon dioxide concentration) and chlorophyll content at the seedling, jointing, and booting stages. Moreover, the non-stomatal factor responsible for the net decrease in photosynthetic efficiency was identified as the decrease in fluorescence resulting from the decreased amount of chlorophyll a returning from the excited to the ground energy state. The content of superoxide anions and hydrogen peroxide in wheat leaves and roots increased with increasing DBP and DEHP supplementation, compared to the control. Antioxidant enzyme activities in the leaves and roots at the seedling stage increased at DBP and DEHP levels of 10 and 20 mg kg^-1, respectively, and the enzyme activities at the jointing and booting stages increased with increasing concentrations of the chemicals, compared to the control. These results demonstrated that increased levels of antioxidant enzymes play a significant role in protecting plant growth under DBP and DEHP stress.