Comprehensive Toxicological Assessment of Halobenzoquinones in Drinking Water at Environmentally Relevant Concentration.

Halobenzoquinones (HBQs), an emerging unregulated category of disinfection byproduct (DBP) in drinking water, have aroused an increasing concern over their potential health risks. However, the chronic toxicity of HBQs at environmentally relevant concentrations remains largely unknown. Here, the occurrence and concentrations of 13 HBQs in drinking water from a northern megacity in China were examined using ultrahigh performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UHPLC-MS/MS). Four HBQs, including 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ), 2,6-dibromo-1,4-benzoquinone (2,6-DBBQ), 2,3,6-trichloro-1,4-benzoquinone (TriCBQ), and 2,5-dibromo-1,4-benzoquinone (2,5-DBBQ), were detected beyond 50% occurrence frequency and at median concentrations from 4 to 50 ng/L. The chronic toxicity of these four HBQs to normal human colon and liver cells (FHC and THLE-2) was investigated at these concentrations. After 90 days of exposure, 2,5-DBBQ and 2,6-DCBQ induced the highest levels of oxidative stress and deoxyribonucleic acid (DNA) damage in colon and liver cells, respectively. Moreover, 2,5-DBBQ and 2,6-DCBQ were also found to induce epithelial-mesenchymal transition (EMT) in normal human liver cells via the extracellular signal regulated kinase (ERK) signaling pathway. Importantly, heating to 100 °C (boiling) was found to efficiently reduce the levels of these four HBQs in drinking water. These results suggested that environmentally relevant concentrations of HBQs could induce cytotoxicity and genotoxicity in normal human cells, and boiling is a highly efficient way of detoxification for HBQs.

Development of an Automated Morphometric Approach to Assess Vascular Outcomes following Exposure to Environmental Chemicals in Zebrafish.

BACKGROUND: Disruptions in vascular formation attributable to chemical insults is a pivotal risk factor or potential etiology of developmental defects and various disease settings. Among the thousands of chemicals threatening human health, the highly concerning groups prevalent in the environment and detected in biological monitoring in the general population ought to be prioritized because of their high exposure risks. However, the impacts of a large number of environmental chemicals on vasculature are far from understood. The angioarchitecture complexity and technical limitations make it challenging to analyze the entire vasculature efficiently and identify subtle changes through a high-throughput in vivo assay. OBJECTIVES: We aimed to develop an automated morphometric approach for the vascular profile and assess the vascular morphology of health-concerning environmental chemicals. METHODS: High-resolution images of the entire vasculature in Tg(fli1a:eGFP) zebrafish were collected using a high-content imaging platform. We established a deep learning-based quantitative framework, ECA-ResXUnet, combined with MATLAB to segment the vascular networks and extract features. Vessel scores based on the rates of morphological changes were calculated to rank vascular toxicity. Potential biomarkers were identified by vessel-endothelium-gene-disease integrative analysis. RESULTS: Whole-trunk blood vessels and the cerebral vasculature in larvae exposed to 150 representative chemicals were automatically segmented as comparable to human-level accuracy, with sensitivity and specificity of 95.56% and 95.81%, respectively. Chemical treatments led to heterogeneous vascular patterns manifested by 31 architecture indexes, and the common cardinal vein (CCV) was the most affected vessel. The antipsychotic medicine haloperidol, flame retardant 2,2-bis(chloromethyl)trimethylenebis[bis(2-chloroethyl) phosphate], and tert-butylphenyl diphenyl phosphate ranked as the top three in vessel scores. Pesticides accounted for the largest group, with a vessel score of ≥1, characterized by a remarkable inhibition of subintestinal venous plexus and delayed development of CCV. Multiple-concentration evaluation of nine per- and polyfluoroalkyl substances (PFAS) indicated a low-concentration effect on vascular impairment and a positive association between carbon chain length and benchmark concentration. Target vessel-directed single-cell RNA sequencing of fli1a+ cells from larvae treated with λ-cyhalothrin, perfluorohexanesulfonic acid, or benzylbutyl phthalate, along with vessel-endothelium-gene-disease integrative analysis, uncovered potential associations with vascular disorders and identified biomarker candidates. DISCUSSION: This study provides a novel paradigm for phenotype-driven screenings of vascular-disrupting chemicals by converging morphological and transcriptomic profiles at a high-resolution level, serving as a powerful tool for large-scale toxicity tests. Our approach and the high-quality morphometric data facilitate the precise evaluation of vascular effects caused by environmental chemicals. https://doi.org/10.1289/EHP13214.

Efficient Photoreduction of CO2 to CO with 100% Selectivity by Slowing Down Electron Transport.

It remains challenging to obtain a single product in the gas-solid photocatalytic reduction of CO2 because CO and CH4 are usually produced simultaneously. This study presents the design of the I-type nested heterojunction TiO2/BiVO4 with controllable electron transport by modulating the TiO2 component. This study demonstrates that slowing electron transport could enable TiO2/BiVO4-4 to generate CO with 100% selectivity. In addition, modifying TiO2/BiVO4-4 by loading a Cu single atom further increased the CO product yield by 3.83 times (17.33 µmol·gcat-1·h-1), while maintaining 100% selectivity for CO. Characterization and density functional theory (DFT) calculations revealed that the selectivity was mainly determined by the electron transport of the support, whereas CO2 was efficiently adsorbed and activated by the Cu single atom. Such a two-step regulation strategy of combining heterojunction with single atom enhances the possibility of simultaneously obtaining high selectivity and high yield in the photocatalytic reduction of CO2.

Associations of Bisphenols Exposure and Hyperuricemia Based on Human Investigation and Animal Experiments.

Hyperuricemia is characterized by elevated blood uric acid (UA) levels, which can lead to certain diseases. Epidemiological studies have explored the association between environmental contaminant exposure and hyperuricemia. However, few studies have investigated the role of chemical exposure in the development of hyperuricemia. Here, we sought to investigate the effects of bisphenol exposure on the occurrence of hyperuricemia. Fifteen bisphenol chemicals (BPs) were detected in human serum and urine samples collected from an area with a high incidence of hyperuricemia in China. Serum UA levels positively correlated with urinary bisphenol S (BPS), urinary bisphenol P (BPP), and serum bisphenol F (BPF). The effects of these three chemicals on UA levels in mice were explored at various exposure concentrations. An increase in serum UA levels was observed in BPS- and BPP-exposed mice. The results showed that BPS exposure increased serum UA levels by damaging the structure of the kidneys, whereas BPP exposure increased serum UA levels by disturbing purine metabolism in the liver. Moreover, BPF did not induce an increase in serum UA levels owing to the inhibition of guanine conversion to UA. In summary, we provide evidence of the mechanisms whereby exposure to three BPs disturbs UA homeostasis. These findings provide new insights into the risks of exposure to bisphenol chemicals.

Effects of oilfield-produced water discharge on the spatial patterns of microbial communities in arid soils.

Recently intensified oil exploitation has resulted in the discharge of large amounts of wastewater containing high concentrations of organic matter and nutrients into the receiving aquatic and soil environments; however, the effects of oilfield-produced water on the soil microbiota are poorly understood. In this study, we conducted a comprehensive analysis to reveal the composition and diversity of the microbial community at horizontal and vertical scales in a typical arid soil receiving oilfield-produced water in Northwest China. Oilfield-produced water caused an increase in microbial diversity at the horizontal scale, and the communities in the topsoil were more variable than those in the subsoil. Additionally, the microbial taxonomic composition differed significantly between the near- and far-producing water soils, with Proteobacteria and Halobacterota dominating the water-affected and reference soil communities, respectively. Soil property analysis revealed that pH, salt, and total organic content influenced the bacterial communities. Furthermore, the oil-produced water promoted the complexity and modularity of distance-associated microbial networks, indicating positive interactions for soil ecosystem function, but not for irrigation or livestock watering. This is the first detailed examination of the microbial communities in soil receiving oilfield-produced water, providing new insights for understanding the microbial spatial distributions in receiving arid soils.

Chronic exposure to polystyrene microplastics increased the chemosensitivity of normal human liver cells via ABC transporter inhibition.

Microplastics (MPs) are ubiquitous in environmental compartments and consumer products. Although liver is frequently reported to be a target organ of MP accumulation in mammals, few studies have focused on MP hepatoxicity in humans. In this study, we used normal human liver cells, THLE-2, to assess the acute and chronic toxicity of polystyrene (PS) MPs with sizes of 0.1 and 1 µm. The results showed that after 48 h of exposure, both kinds of PS MPs could enter THLE-2 cells and cause no obviously acute cytotoxicity at <20 µg/mL. In contrast, metabolomic analysis revealed that 90 days of PS MPs exposure at environmentally relevant dose (0.2 µg/mL) could significantly alter the metabolic profiles of the cells, especially the nanosized MPs. KEGG pathway analysis showed that the ATP-binding cassette (ABC) transporter pathway was the most significantly changed pathway. Cell functional tests confirmed that chronic PS MP treatment could inhibit the activity of the ABC efflux transporter and further increase the cytotoxicity of arsenic, indicating that the PS MPs had a chemosensitizing effect. These findings underline the chronic risk of MPs to human liver.

The critical role of microplastics in the fate and transformation of sulfamethoxazole and antibiotic resistance genes within vertical subsurface-flow constructed wetlands.

Constructed wetlands (CWs) are reservoirs of microplastics (MPs) in the environment. However, knowledge about the impact of MPs on antibiotic removal and the fate of antibiotic resistance genes (ARGs) is limited. We focused on sulfamethoxazole (SMX) as a representative compound to examine the effects of MPs on SMX removal and the proliferation and dissemination of two SMX-related ARGs (sul1 and sul2) in vertical subsurface-flow CW (VFCW) microcosm. The presence of MPs in the substrate was found to enhance the proliferation of microorganisms owing to the large specific surface area of the MPs and the release of dissolved organic carbon (DOC) on MP surfaces, which resulted in a high SMX removal ranging from 97.80 % to 99.80 %. However, the presence of MPs promoted microbial interactions and the horizontal gene transfer (HGT) of ARGs, which led to a significant increase in the abundances of sul1 and sul2 of 68.47 % and 17.20 %, respectively. It is thus imperative to implement rigorous monitoring strategies for MPs to mitigate their potential ecological hazards.

Nanoenabled Enhancement of Plant Tolerance to Heat and Drought Stress on Molecular Response.

Global warming has posed significant pressure on agricultural productivity. The resulting abiotic stresses from high temperatures and drought have become serious threats to plants and subsequent global food security. Applying nanomaterials in agriculture can balance the plant's oxidant level and can also regulate phytohormone levels and thus maintain normal plant growth under heat and drought stresses. Nanomaterials can activate and regulate specific stress-related genes, which in turn increase the activity of heat shock protein and aquaporin to enable plants' resistance against abiotic stresses. This review aims to provide a current understanding of nanotechnology-enhanced plant tolerance to heat and drought stress. Molecular mechanisms are explored to see how nanomaterials can alleviate abiotic stresses on plants. In comparison with organic molecules, nanomaterials offer the advantages of targeted transportation and slow release. These advantages help the nanomaterials in mitigating drought and heat stress in plants.

Triggering photocatalytic performance of La2CoxMn2-xO6 via heat activation.

The La-based perovskite (LaBO3) exhibits excellent optical properties. However, its valence band (VB) potential is not sufficiently positive to reach the oxidation potential required for the cleavage of chemical bonds (such as benzylic C-H), limiting its application in photocatalysis. Herein, we report the unconventional effects of heat activation on the reduction of the dissociation energy of benzylic C-H and aqueous H-O, thereby triggering the photocatalytic activity of La2CoxMn2-xO6 perovskites. Additionally, we demonstrate that photocatalysis is the main contributor to substrate conversion in the selective oxidation of toluene and reduction of CO2. Particularly, La2Co1.5Mn0.5O6 shows excellent performance with a product yield of 550.00 mmol gcat-1 and a toluene conversion of 22,866.67 µmol gcat-1 h-1. To the best of our knowledge, this is the highest reported product yield for the selective oxidation of benzylic C-H bond of toluene. Our findings provide insight into the specific role of heat activation in photocatalysis, which is crucial for breaking and overcoming the VB barrier to realize challenging reactions.

Direct Uptake and Intracellular Dissolution of HgS Nanoparticles: Evidence from a Bacterial Biosensor Approach.

Mercury sulfide nanoparticles (HgSNPs), which occur widely in oxic and anoxic environments, can be microbially converted to highly toxic methylmercury or volatile elemental mercury, but it remains challenging to assess their bioavailability. In this study, an Escherichia coli-based whole-cell fluorescent biosensor was developed to explore the bioavailability and microbial activation process of HgSNPs. Results show that HgSNPs (3.17 ± 0.96 nm) trigger a sharp increase in fluorescence intensity of the biosensor, with signal responses almost equal to that of ionic Hg (Hg(II)) within 10 h, indicating high bioavailability of HgSNP. The intracellular total Hg (THg) of cells exposed to HgSNPs (200 µg L-1) was 3.52-8.59-folds higher than that of cells exposed to Hg(II) (200 µg L-1), suggesting that intracellular HgSNPs were only partially dissolved. Speciation analysis using size-exclusion chromatography (SEC)-inductively coupled plasma mass spectrometry (ICP-MS) revealed that the bacterial filtrate was not responsible for HgSNP dissolution, suggesting that HgSNPs entered cells in nanoparticle form. Combined with fluorescence intensity and intracellular THg analysis, the intracellular HgSNP dissolution ratio was estimated at 22-29%. Overall, our findings highlight the rapid internalization and high intracellular dissolution ratio of HgSNPs by E. coli, and intracellular THg combined with biosensors could provide innovative tools to explore the microbial uptake and dissolution of HgSNPs.

Spatial nanopores promote laccase degradation of bisphenol A and its analogs.

Bisphenol A (BPA) and its analogs are endocrine-disrupting chemicals that are frequently detected in environmental and human samples. However, the effective removal of BPA and its analogs has not yet been extensively studied. Herein, we introduce a novel enzyme reactor for the degradation of BPA and its analogs in water. The influence of pore size on the degradation efficiency of immobilized laccase in the spatial nanopores of hydrogel was investigated using BPA as a representative compound. This showed that nanopores enhance the activity of immobilized laccases in a pore size-dependent manner and increase their stability. Compared with the same amount of free laccase, the 50 mg/L BPA degradation performance of laccase immobilized in 76 nm nanopores increased to 300 %. Taking advantage of magnetic separation, this immobilized laccase can be reused, and its degradation capacity was maintained at over 73.7 % after ten reactions. Moreover, the degradation of seven BPA analogs was 1.03-5.88 times higher using laccase immobilized in nanopores compared with free laccase. Also, the biocatalyst could efficiently degrade BPA analogs in real water matrix. This study opens up a new avenue for the removal of BPA and its analogs by immobilizing laccase in nanopores, overcoming the key limitations introduced by the short enzyme life span and non-reusability.

Occurrence, placental transfer, and health risks of emerging endocrine-disrupting chemicals in pregnant women.

Previous studies demonstrated that many environmental chemicals can cross the human placental barrier. However, the risk regarding gestational exposure of emerging endocrine-disrupting chemicals (EDCs) is unclear. In this study, the occurrence of 24 EDCs, such as bisphenol A analogs, parabens, triclocarban, and triclosan, was investigated in serum and urine samples from Chinese pregnant women. Some metabolites were determined in matched serum-urine pairs (n = 75) to perform a comprehensive assessment of exposure. The placental transfer efficiency (PTE) of the detected chemicals was determined in matched maternal-cord serum pairs (n = 110). The mean PTEs of the chemicals showed a large variation from 43.1% to 171.0%. The potential effects of physicochemical properties, molecular structures, and biological factors on PTE were investigated using multiple linear regression models and molecular docking. We found that the PTE of methyl paraben, ethyl paraben, and propyl paraben was associated with their increasing alkyl chain lengths. Furthermore, a comprehensive exposure assessment of EDCs showed that 62.7% of pregnant women had a health index > 1, which indicted potential health risks during pregnancy. However, toxicity and the underlying mechanisms of these EDCs remain to be further studied.

Surface Modification Determines the Distribution and Toxicity of Quantum Dots during the Development of Early Staged Zebrafish.

Surface modifications are generally used to functionalize QDots to improve their properties for practical applications, but the relationship between QDot modification and biological activity is not well understood. Using an early staged zebrafish model, we investigated the biodistribution and toxicity of CdSe/ZnS QDots with four types of modifications, including anionic poly(ethylene glycol)-carboxyl ((PEG)n-COOH), anionic mercaptopropionic acid (MPA), zwitterionic glutathione (GSH), and cationic cysteamine (CA). None of the QDots showed obvious toxicity to zebrafish embryos prior to hatching because the zebrafish chorion is an effective barrier that protects against QDot exposure. The QDots were mainly absorbed on the epidermis of the target organs after hatching and were primarily deposited in the mouth and gastrointestinal tract when the zebrafish started feeding. CA-QDots possessed the highest adsorption capacity; however, (PEG)n-COOH-QDots showed the most severe toxicity to zebrafish, as determined by mortality, hatching rate, heartbeat, and malformation assessments. It shows that the toxicity of the QDots is mainly attributed to ROS generation rather than Cd2+ release. This study provides a comprehensive understanding of the environmental and ecological risks of nanoparticles in relation to their surface modification.

Efficient Photo-Assisted Thermal Selective Oxidation of Toluene Using N-Doped TiO2.

Selective oxidation of toluene is a key reaction to produce high value-added products but remains a big challenge. In this study, we introduce a nitrogen-doped TiO2 (N-TiO2) catalyst to create more Ti3+ and oxygen vacancy (OV), which act as active sites for selective oxidation of toluene via activating O2 to superoxide radical (•O2-). Interestingly, the resulting N-TiO2-2 exhibited an outstanding photo-assisted thermal performance with a product yield of 209.6 mmol·gcat-1 and a toluene conversion of 10960.0 µmol·gcat-1·h-1, which are 1.6 and 1.8 times greater than those obtained under thermal catalysis. We showed that the enhanced performance under photo-assisted thermal catalysis was attributed to more active species generation by making full use of photogenerated carriers. Our work suggests a viewpoint to apply a noble-metal-free TiO2 system in the selective oxidation of toluene under solvent-free conditions.

Enhanced depolluting capabilities of microbial bioelectrochemical systems by synthetic biology.

Microbial bioelectrochemical system (BES) is a promising sustainable technology for the electrical energy recovery and the treatment of recalcitrant and toxic pollutants. In microbial BESs, the conversion of harmful pollutants into harmless products can be catalyzed by microorganisms at the anode (Type I BES), chemical catalysts at the cathode (Type II BES) or microorganisms at the cathode (Type III BES). The application of synthetic biology in microbial BES can improve its pollutant removing capability. Synthetic biology techniques can promote EET kinetics, which is helpful for microbial anodic electro-respiration, expediting pollutant removing not only at the anode but also at the cathode. They offer tools to promote biofilm development on the electrode, enabling more microorganisms residing on the electrode for subsequent catalytic reactions, and to overexpress the pollutant removing-related genes directly in microorganisms, contributing to the pollutant decomposition. In this work, based on the summarized aspects mentioned above, we describe the major synthetic biology strategies in designing and improving the pollutant removing capabilities of microbial BES. Lastly, we discuss challenges and perspectives for future studies in the area.

Comparative cytotoxicity analyses of disinfection byproducts in drinking water using dimensionless parameter scaling method: Effect of halogen substitution type and number.

Up to date, over 700 disinfection byproducts (DBPs) have been detected and identified in drinking water. It has been recognized that cytotoxicity of DBPs varied significantly among groups. Even within the same group, cytotoxicity of different DBP species was also different due to different halogen substitution types and numbers. However, it is still difficult to quantitatively determine the inter-group cytotoxicity relationships of DBPs under the effect of halogen substitution in different cell lines, especially when a large number of DBP groups and multiple cytotoxicity cell lines are involved. In this study, a powerful dimensionless parameter scaling method was adopted to quantitatively determine the relationship of halogen substitution and the cytotoxicity of various DBP groups in three cell lines (i.e., the human breast carcinoma (MVLN), Chinese hamster ovary (CHO), and human hepatoma (Hep G2) cell cytotoxicity) with no need to consider their absolute values and other influences. By introducing the dimensionless parameters Dx-orn-speciescellline and D¯x-orn-speciescellline, as well as their corresponding linear regression equation coefficients ktypeornumbercellline and k¯typeornumbercellline, the strength and trend of halogen substitution influences on the relative cytotoxic potency could be determined. It was found that the effect of halogen substitution type and number on the cytotoxicity of DBPs followed the same patterns in the three cell lines. The CHO cell cytotoxicity was the most sensitive cell line to evaluate the effect of halogen substitution on the aliphatic DBPs, whereas the MVLN cell cytotoxicity was the most sensitive cell line to evaluate the effect of halogen substitution on the cyclic DBPs. Notably, seven quantitative structure activity relationship (QSAR) models were established, which could not only predict the cytotoxicity data of DBPs, but also help to explain and verify the patterns of halogen substitution effect on cytotoxicity of DBPs.

Tailored Cl- Ligation on Supported Pt Catalysts for Selective Primary C-H Bond Oxidation.

It is challenging to achieve high selectivity over Pt-metal-oxide catalysts widely used in many selective oxidation reactions because Pt is prone to over-oxidize substrates. Herein, our sound strategy for enhancing the selectivity is to saturate the under-coordinated single Pt atoms with Cl- ligands. In this system, the weak electronic metal-support interactions between Pt atoms and reduced TiO2 cause electron extraction from Pt to Cl- ligands, resulting in strong Pt-Cl bonds. Therefore, the two-coordinate single Pt atoms adopt a four-coordinate configuration and thus inactivated, thereby inhibiting the over-oxidation of toluene over Pt sites. The selectivity for the primary C-H bond oxidation products of toluene was increased from 50.1 to 100%. Meanwhile, the abundant active Ti3+ sites were stabilized in reduced TiO2 by Pt atoms, leading to a rising yield of the primary C-H oxidation products of 249.8 mmol gcat-1. The reported strategy holds great promise for selective oxidation with enhanced selectivity.

Obesogenic effect of Bisphenol P on mice via altering the metabolic pathways.

Bisphenol P (BPP), structurally similar to bisphenol A, is commonly identified in the samples of environment, food, and humans. Unfortunately, very little information is currently available on adverse effects of BPP. The obesogenic effects and underlying mechanisms of BPP on mice were investigated in this study. Compared with the control, high-resolution microcomputed tomography (micro-CT) scans displayed that the visceral fat volume of mice was significantly increased at a dose of 5 mg/kg/day after BPP exposure for 14 days, whereas the subcutaneous fat volume remained unchanged. Nontargeted metabolomic analysis revealed that BPP significantly perturbed the metabolic pathways of mouse livers, and acetyl-CoA was identified as the potential key metabolite responsible for the visceral fat induced by BPP. These findings recommend that a great deal of attention should be paid to the obesogenic properties of BPP as a result of its widely utilized and persistence in the environment.

Entropy-Driven Three-Dimensional DNA Nanofireworks for Simultaneous Real-Time Imaging of Telomerase and MicroRNA in Living Cells.

Real-time monitoring of different types of intracellular tumor-related biomarkers is of key importance for the identification of tumor cells. However, it is hampered by the low abundance of biomarkers, inefficient free diffusion of reactants, and complex cytoplasmic milieu. Herein, we present a stable and general method for in situ imaging of microRNA-21 and telomerase utilizing simple highly integrated dual tetrahedral DNA nanostructures (TDNs) that can naturally enter cells, which could initiate to form the three-dimensional (3D) higher-order DNA superstructures (DNA nanofireworks, DNFs) through a reliable target-triggered entropy-driven strand displacement reaction in living cells for remarkable signal amplification. Importantly, the excellent biostability, biocompatibility, and sensitivity of this approach benefited from (i) the precise multidirectional arrangement of probes with a pure DNA structure and (ii) the local target concentration enhanced by the spatially confined microdomain inside the DNFs. This strategy provides a pivotal molecular toolbox for broad applications such as biomedical imaging and early precise cancer diagnosis.