An ultrasensitive free-of-electronic sacrificial agent photoelectrochemical aptasensor for the detection of dibutyl phthalate based on Z-scheme p-n Bi-doped BiOI/Bi2S3 heterojunction.

Dibutyl phthalate (DBP), a common and outstanding plasticizer, exhibits estrogenic, mutagenic, carcinogenic, and teratogenic properties. It is easily liberated from plastic materials and pollutes aquatic ecosystems, endangering human health. Therefore, highly sensitive and selective DBP detection methods are necessary. In this work, a free-of-electronic sacrificial agent photoelectrochemical (PEC) aptasensor for DBP detection was constructed using a novel Z-scheme Bi-doped BiOI/Bi2S3 (Bi-BIS) p-n heterojunction. The Bi-BIS composites had higher visible-light absorption, charge transfer, and separation efficiency. This is attributed to the synergistic effect of the formation of Z-scheme p-n heterojunction between BiOI and Bi2S3, the plasma resonance effect of metallic Bi and photosensitization of Bi2S3, thus exhibiting large and stable photocurrent response in the absence of electron sacrificial agent, that was 10.4 and 6.4 times higher than that of BiOI and Bi2S3, respectively. Then, a DBP PEC aptasensor was constructed by modifying the DBP aptamer on the surface of the ITO/Bi-BIS electrode. The aptasensor demonstrated a broad linear range (2-500 pM) and a low detection limit (0.184 pM). What's more, because there is no interference from electronic sacrificial agent, the aptasensor exhibited excellent selectivity in real water samples. Therefore, the proposed PEC has considerable potential for DBP monitoring.

Aggregated health risk assessment of perfluoroalkyl acids migrated from convenience food contact materials.

Ingestion of perfluoroalkyl acids (PFAAs) via contaminated food contact materials (FCMs) is an important human exposure source. This study adopts a toxicity equivalent approach to evaluate the collective health risk of multiple PFAAs in FCMs. A comprehensive extraction and analysis of 21 PFAAs in FCMs was performed. Among the analyzed substances, 15 PFAAs were detected. Migration experiment using three food simulants revealed the migration range of seven PFAAs from FCMs into the simulant to be 0.47-46.7 ng/cm2. The hazard quotient results suggest minimal health risk, except for 9% of packaged samples where perfluorooctanoic acid (PFOA) poses a higher risk. Utilizing PFOA toxic equivalent concentrations, comprehensive risk calculations showed ∼77% of samples potentially posing elevated health risks due to PFAA exposure. This emphasizes the substantial contribution of PFAAs beyond PFOA and underscores the importance of considering them in related assessments. The aggregated risk assessment reflects actual exposure circumstances more accurately.

Organophosphorus flame retardants in the Qiantang River of China: occurrence, source and ecological risk assessment.

In recent years, the prevalence and danger of organophosphorus flame retardants (OPFRs) have drawn attention from all around the world. This study examined twenty-five OPFRs observed in water and sediment samples from the Qiantang River in eastern China, as well as their occurrence, spatial distribution, possible origins, and ecological hazards. All the 25 OPFRs were detected in water and sediment samples. The levels of Σ25OPFRs in water and sediment were 35.5-192 ng/L and 8.84-48.5 ng/g dw, respectively. Chlorinated OPFRs were the main contributions in water, whereas alkyl-OPFRs were the most common congeners found in sediment. Spatial analysis revealed that sample locations in neighboring cities had somewhat higher water concentrations of OPFRs. Slowing down the river current and making the reservoir the main sink of OPFRs, the dam can prevent OPFRs from moving via the Qiantang River. Positive matrix factorization indicated that plasticizer in polyvinyl chloride, polyester resins, and polyurethane foam made the greatest contributions in water, whereas polyurethane foam and textile were the predominant source in sediment. Analysis of sediment-water exchange of OPFRs showed that twelve OPFRs in sediments can re-enter into the water body. The risk quotients showed the ecological risk was low to medium, but trixylyl phosphate exposures posed high ecological risk to aquatic organisms.

Disruption of zebrafish sex differentiation by emerging contaminants hexafluoropropylene oxides at environmental concentrations via antagonizing androgen receptor pathways.

As alternatives of perfluorooctanoic acid (PFOA), hexafluoropropylene oxide dimeric acid (HFPO-DA) and trimeric acid (HFPO-TA) have been detected increasingly in environmental media and even humans. They have been shown to exhibit reproductive toxicity to model species, but their effects on human remain unclear due to the knowledge gap in their mode of action. Herein, (anti-)androgenic effects of the two HFPOs and PFOA were investigated and underlying toxicological mechanism was explored by combining zebrafish test, cell assay and molecular docking simulation. Exposure of juvenile zebrafish to the chemicals during sex differentiation promoted feminization, with HFPO-TA acting at an environmental concentration of 1 µg/L. The chemicals inhibited proliferation of human prostate cells and transcriptional activity of human and zebrafish androgen receptors (AR), with HFPO-TA displaying the strongest potency. Molecular docking revealed that the chemicals bind to AR in a conformation similar to a known AR antagonist. Combined in vivo, in vitro and in silico results demonstrated that the chemicals disrupted sex differentiation likely by antagonizing AR-mediated pathways, and provided more evidence that HFPO-TA is not a safe alternative to PFOA.

Perfluorooctane sulfonate promotes the migration of colorectal cancer cells by inducing epithelial-mesenchymal transition.

The potential association between colorectal cancer (CRC) and environmental pollutants is worrisome. Previous studies have found that some perfluoroalkyl acids, including perfluorooctane sulfonate (PFOS), induced colorectal tumors in experimental animals and promoted the migration of and invasion by CRC cells in vitro, but the underlying mechanism is unclear. Here, we investigated the effects of PFOS on the proliferation and migration of CRC cells and the potential mechanisms involving activating the PI3K/Akt-NF-κB signal pathway and epithelial-mesenchymal transition (EMT). It was found that PFOS promoted the growth and migration of HCT116 cells at non-cytotoxic concentrations and increased the mRNA expression of the migration-related angiogenic cytokines vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8). In a mechanistic investigation, the up-stream signal pathway PI3K/Akt-NF-κB was activated by PFOS, and the process was suppressed by LY294002 (PI3K/Akt inhibitor) and BAY11-7082 (NF-κB inhibitor) respectively, leading to less proliferation of HCT116 cells. Furthermore, matrix metalloproteinases (MMP) and EMT-related markers were up-regulated after PFOS exposure, and were also suppressed respectively by LY294002 and BAY11-7082. Moreover, the up-regulation of EMT markers was suppressed by a MMP inhibitor GM6001. Taken together, our results indicated that PFOS promotes colorectal cancer cell migration and proliferation by activating the PI3K/Akt-NF-κB signal pathway and epithelial-mesenchymal transition. This could be a potential toxicological mechanism of PFOS-induced malignant development of colorectal cancer.

Sulfonamide disinfection byproducts exhibited severe toxicity to human commensal bacteria.

Many antibiotic disinfection byproducts have been detected but their toxicity has not been evaluated adequately. In this report, the chlorination reaction kinetics of five common sulfamides (SAs), reaction intermediates and their toxicity were investigated. Chlorination of sulfapyridine (SPD), sulfamethazine (SMT), sulfathiazole (STZ), and sulfisoxazole (SIZ) followed the second-order kinetics, and were degraded completely within 10 min. A large number of reaction intermediates were deteced by LC-MS, among which a total of 16 intermediates were detected for the first time. Toxicity of the five SAs chlorination solutions was evaluated separately by examining their effects on the growth rate of S. salivarius K12, a commensal bacterium in the human digestive system. After 30 min chlorination, solutions of SMT, STZ and sulfadiazine (SDZ) each exhibited severe toxicity by inhibiting the bacteria growth completely, whereas the inhibition was only 50 % and 20  % by SIZ and SPD respectively. Based on the comparison between toxicity test results and mass spectra, three SA chlorination intermediates, m/z 187.2 (C10H10N4), m/z 287.2 (C9H7N3O4S2) and m/z 215 (C7H10N4O2S/C12H14N4) were proposed to be the primary toxicants in the chlorination products. Our study demonstrated the power of combined approach of chemical analysis and toxicity testing in identifying toxic disinfection byproducts, and highlighted the ne ed for more research on the toxicity evaluation and risk assessment of antibiotic disinfection byproducts.

Emerging organophosphate ester resorcinol bis(diphenyl phosphate) exerts estrogenic effects via estrogen receptor pathways.

Environmental occurrence and human exposure of emerging organophosphate esters (eOPEs) have increased significantly in recent years. Resorcinol bis(diphenyl) phosphate (RDP) is one of the major eOPEs detected in indoor dust, but the knowledge on its toxicities and health risks is rather limited. In this study, we investigated the in vitro estrogenic effects and underlying mechanism of RDP in comparison with a legacy OPE triphenyl phosphate (TPHP). Our results showed that RDP promoted MCF-7 cell proliferation with the lowest effect concentration of 2.5 µM, and the maximum enhancement of 1.6 folds is greater than that of TPHP (1.3 folds). The effect was inhibited completely by an estrogen receptor (ER) antagonist, suggesting that ER activation was responsible for the enhancement. In luciferase reporter gene assays both RDP and TPHP activated ER transcriptional activity at 2.5 µM, but RDP activity was higher than TPHP. Competitive fluorescence binding assays showed that RDP bound to ER with an IC10 of 0.26 µM, which is 20 folds lower than TPHP (5.6 µM). Molecular docking simulation revealed that both RDP and TPHP interacted with ER at the binding pocket of estradiol, although the hydrogen bonds were different. Taken together, RDP exerted stronger estrogenic effects than TPHP through ER-mediated pathways and may pose more health risks.

Enantiomer-specific burden of metalaxyl and myclobutanil in non-occupationally exposed population with evidence from dietary intake and urinary excretion.

Metalaxyl (MET) and myclobutanil (MYC) are two widely used chiral fungicides that may pose health risks to non-occupationally exposed populations. Here, the two fungicides were enantiomer-specific quantified in the dietary food and urine of residents in an Eastern China city, to determine the exposure and excretion of these contaminants in different populations. Results indicate that residues of MET and MYC varied with different food items at 0.42-0.86 ng/g fresh weight (FW) and 0.18-0.33 ng/g FW, respectively. In urine samples, the residual levels after creatinine adjusting (CR) ranged from 10.2 to 1715.4 ng/g CR for MET and were below the detection limit up to 320.7 ng/g CR for MYC. Significant age- and gender-related differences were separately found in urinary MET and MYC of different populations. Monte-Carlo simulations suggested that children had higher daily dietary intake (DDI) but lower urinary excretion (DUE) rates than youths, and thus may suffer higher body burdens. The residues of antifungally ineffective enantiomers (S-MET and R-MYC) were slightly higher than their antipodes in foods. Moreover, the enantiomer-selective urinary excretion resulted in higher retention of S-MET and R-MYC in the human body. Our results suggest that both dietary intake and urinary excretion should be enantiomer-specifically considered when assessing the exposure risk and body burden of chiral fungicides in the non-occupationally exposed population. Furthermore, substitutive application of enantiomer-enriched fungicide formulations can not only benefit the antifungal efficacy but also be safer for human health.

Activation of estrogen-related receptor: An alternative mechanism of hexafluoropropylene oxide homologs estrogenic effects.

Perfluorooctanoic acid (PFOA) alternatives such as hexafluoropropylene oxide homologs (HFPOs) cause concern due to increased occurrence in the environment as well as potential bioaccumulation and toxicity. HFPOs have been demonstrated to activate the estrogen receptor (ER) pathway. The ER pathway is homologous and connected to the estrogen-related receptor (ERR) pathway, but HFPOs effects on the ERR pathway have not been studied. Hence, we assessed the potential estrogenic effects of HFPOs via ERRγ pathway. In vitro assays revealed that HFPO dimeric, trimeric, and tetrameric acids (HFPO-DA, -TA, and -TeA, respectively), acted as ERRγ agonists, activating the transcription of both human and zebrafish ERRγ at low concentrations, but inhibiting zebrafish ERRγ at high concentrations. We also found that HFPO-TA promoted the human endometrial cancer cells (Ishikawa cells) proliferation via ERRγ/EGF, Cyclin D1 pathway. The HFPO-TA-induced proliferation of Ishikawa cells was inhibited by co-exposure with a specific antagonist of ERRγ, GSK5182. In vivo exposure of female zebrafish to HFPO-TA disturbed sex hormone levels, interfered with the gene expression involved in estrogen synthesis and follicle regulation, and caused histopathological lesions in the ovaries, which were similar to those induced by a known ERRγ agonist GSK4716. Taken together, this study revealed a new mechanism concerning the estrogenic effect of HFPOs via activation of the ERRγ pathway.

Contaminant occurrence, water quality criteria and tiered ecological risk assessment in water: A case study of antifouling biocides in the Qiantang River and its estuary, Eastern China.

Antifouling biocides may cause adverse effects on non-target species. This study aims to determine the distribution, sources, and ecological risks of antifouling biocides in the surface waters of the Qiantang River and its estuary in eastern China. The concentrations of total antifouling biocides were ranged from 12.9 to 215 ng/L for all water samples. Atrazine, diuron and tributyltin were the major compounds in the water bodies of the study area. The acute and chronic toxicity criteria for tributyltin, diuron and atrazine were derived for freshwater and saltwater, respectively, based on the species sensitivity distribution approach. The freshwater and saltwater criteria were slightly different, and the toxicity to aquatic organisms could be summarized as tributyltin > diuron > atrazine. The graded ecological risk rating showed that the long-term risk of TBT was significant in coastal waters. The pollution of TBT in the Qiantang River deserves further attention.

Toxicological mechanisms of emerging per-/poly-fluoroalkyl substances: Focusing on transcriptional activity and gene expression disruption.

Environmental and human monitoring studies have witnessed increasing occurrence of emerging per-/poly-fluoroalkyl substances (ePFASs) worldwide. Three classes of ePFASs, namely chlorinated polyfluoroalkylether sulfonic acids, hexafluoropropylene oxide homologues and short-chain perfluoroalkyl acids attracted the most attention. It is, therefore, the goal of this review to systematically and critically analyse the toxicity and toxicological mechanisms of these ePFASs based on the papers published between 2017 and 2022. The review summarized the main findings from both in vivo and in vitro studies, covering the hepatotoxicity of ePFASs and their interference with the endocrine system, including reproductive, developmental and thyroid toxicity. It also summarized the changes in gene expression in the hypothalamic-pituitary-thyroid axis and hypothalamic-pituitary-gonad axis of the model organisms after ePFASs exposure. The changes in gene expression in vitro and in vivo provide a clearer understanding of the toxicological mechanisms of ePFASs interference on hormonal levels (i.e., estradiol, testosterone, and thyroid hormones), developmental disturbance (e.g., swim bladder dysfunction) and lipid metabolism disruption (e.g., lipid droplet accumulation and hepatomegaly). In the end, future research directions on the toxicological mechanisms of ePFASs are suggested.

Direct and gut microbiota-mediated toxicities of environmental antibiotics to fish and aquatic invertebrates.

The accumulation of antibiotics in the environment has ecological impacts that have received less attention than the human health risks of antibiotics, although the effects could be far-reaching. This review discusses the effects of antibiotics on the health of fish and zooplankton, manifesting in direct or dysbiosis-mediated physiological impairment. Acute effects of antibiotics in these organism groups are usually induced at high concentrations (LC50 at ∼100-1000 mg/L) that are not commonly present in aquatic environments. However, when exposed to sub-lethal, environmentally relevant levels of antibiotics (ng/L-µg/L) disruption of physiological homeostasis, development, and fecundity can occur. Antibiotics at similar or lower concentrations can induce dysbiosis of gut microbiota which can affect the health of fish and invertebrates. We show that the data about molecular-level effects of antibiotics at low exposure concentrations are limited, hindering environmental risk assessment and species sensitivity analysis. Fish and crustaceans (Daphnia sp.) were the two groups of aquatic organisms used most often for antibiotic toxicity testing, including microbiota analysis. While low levels of antibiotics impact the composition and function of gut microbiota in aquatic organisms, the correlation and causality of these changes to host physiology are not straightforward. In some cases, negative or lack of correlation have occurred, and, unexpectedly, gut microbial diversity has been unaffected or increased upon exposure to environmental levels of antibiotics. Efforts to incorporate functional analyses of gut microbiota are beginning to provide valuable mechanistic information, but more data is needed for ecological risk assessment of antibiotics.

Putative adverse outcome pathways of the male reproductive toxicity derived from toxicological studies of perfluoroalkyl acids.

Adverse outcome pathway (AOP) as a conceptual framework is a powerful tool in the field of toxicology to connect seemingly discrete events at different levels of biological organizations into an organized pathway from molecular interactions to whole organism toxicity. Based on numerous toxicological studies, eight AOPs for reproductive toxicity have been endorsed by the Organization for Economic Co-operation and Development (OECD) Task Force on Hazard Assessment. We have conducted a literature survey on the mechanistic studies on male reproductive toxicity of perfluoroalkyl acids (PFAAs), a class of global environmental contaminants with high persistence, bioaccumulation and toxicity. Using the AOP development strategy, five new AOPs for male reproductive toxicity were proposed here, namely (1) changes in membrane permeability leading to reduced sperm motility, (2) disruption of mitochondrial function leading to sperm apoptosis, (3) decreased gonadotropin-releasing hormone (GnRH) expression in hypothalamus leading to reduced testosterone production in male rats, (4) activation of the p38 signaling pathway leading to disruption of BTB in mice, (5) inhibition of p-FAK-Tyr407 activity leading to the destruction of BTB. The molecular initiating events in the proposed AOPs are different from those in the endorsed AOPs, which are either receptor activation or enzyme inhibition. Although some of the AOPs are still incomplete, they can serve as a building block upon which full AOPs can be developed and applied to not only PFAAs but also other chemical toxicants with male reproductive toxicity.

A cathodic photoelectrochemical immunoassay with dual signal amplification for the ultrasensitive detection of DNA damage biomarkers.

Toxicity screening and risk assessment of an overwhelmingly large and ever-increasing number of chemicals are vitally essential for ecological safety and human health. Genotoxicity is particularly important because of its association with mutagenicity, carcinogenicity and cancer. Phosphorylated histone H2AX (γH2AX) is an early sensitive genotoxic biomarker. It is therefore highly desirable to develop analytical methods for the detection of trace γH2AX to enable screening and assessment of genotoxicity. Here, we developed a novel cathodic photoelectrochemical (PEC) immunoassay with dual signal amplification for the rapid and ultrasensitive detection of γH2AX in cell lysates. A sandwich immuno-reaction targeting γH2AX was first carried out on a 96-well plate, using a secondary antibody/gold nanoparticle/glucose oxidase conjugate as the labeled detection antibody. The conjugate increased the production of H2O2 and thus provided the first mechanism of signal amplification. The immuno-reaction product containing H2O2 was then detected on a photocathode prepared from Bi2+xWO6 rich in oxygen vacancies, with H2O2 acting as electron acceptor. The oxygen vacancies acted as both adsorption and activation sites of H2O2 and thus enhanced the photocurrent, which provided another mechanism of signal amplification. As a result, an ultrasensitive immunoassay for γH2AX determination was established with a limit of detection of 6.87 pg/mL (S/N = 3) and a wide linear range from 0.01 to 500 ng/mL. The practicability of this assay was verified by detecting γH2AX in cell lysates exposed to known genotoxic chemicals. Our work offers a promising tool for the screening of genotoxic chemicals and opening a new avenue toward environmental risk assessment.

Water quality criteria derivation and tiered ecological risk evaluation of antifouling biocides in marine environment.

This study provides a comprehensive compilation of published toxicological and environmental data further used to assess the ecological risks of six antifouling biocides, including tributyltin (TBT), Irgarol 1051, Diuron, Chlorothalonil, 4,5-Dichloro-N-octyl-3(2H)-isothiazolone (DCOIT), and Dichlofluanid. The standard maximum concentration and standard continuous concentration of antifouling biocides were derived by the species susceptibility distribution method. Following that, the ecological risk assessment of antifouling biocides in the aquatic environment was conducted using the hazard quotient, margin of safety, joint probability curve, and Monte Carlo random sampling method. The following is a concise list of the antifouling biocide dangers associated with acute and chronic risks: Irgarol 1051 > TBT > Diuron > DCOIT > Chlorothalonil > Dichlofluanid. It is strongly advised that systematic and ongoing monitoring of these biocides in coastal areas take place, as well as the creation of acceptable and efficient environmental protection measures, to safeguard the coastal environment's services and functions.

Antibiotics disrupt lipid metabolism in zebrafish (Danio rerio) larvae and 3T3-L1 preadipocytes.

Antibiotics are emerging environmental contaminants with wide attention due to their high consumption and pseudo-persistence in the environment. They have been shown to induce obesity or obesity-related metabolic diseases in experimental animals, but the underlying toxicological mechanisms remain unclear. Here, the disruptive effects of four commonly used antibiotics, namely doxycycline (DC), enrofloxacin (ENR), florfenicol (FF) and sulfamethazine (SMT) on lipid metabolism were investigated in zebrafish (Danio rerio) larvae and murine preadipocyte cell line. Triglyceride (TG) content was reduced after 1 ng/L DC or ENR exposure but was increased at higher concentrations up to 100 mg/L. FF increased and SMT reduced TG content but did not show any concentration dependence. None of the antibiotics had any significant effect on total cholesterol (TC) content in zebrafish except 100 µg/L SMT. Expression levels of 8 lipid metabolism-related genes were also quantified. SMT was most disruptive by up-regulating six genes, followed by FF which up-regulated four genes and down-regulated one gene, whereas DC and ENR both up-regulated one gene. In 3T3-L1 preadipocytes, ENR, FF, and SMT in general increased TG content, while 100 mg/L FF reduced TG substantially. DC did not show any effect up to 10 mg/L, at which TG increased significantly. FF and SMT increased TC slightly at low concentrations but reduced it at high concentrations, whereas TC, DC and ENR had no effect at any tested concentrations. Gene expression measurement also indicated that SMT was most disruptive, followed by FF, DC, and ENR. Reporter gene assays showed that only SMT inhibited the transcriptional activity of peroxisome proliferator-activated receptor γ (PPARγ). The above experimental results and clustering analysis demonstrate that the four antibiotics exerted disruption on lipid metabolism through different mechanisms, and one of the mechanisms for SMT may be inhibition of PPARγ transcriptional activity.

Silver and Hyaluronic Acid-Coated Gold Nanoparticles Modulate the Metabolism of a Model Human Gut Bacterium Lactobacillus casei.

Medical applications of nanotechnology are promising in creating efficient and targeted therapies. However, so far, nanodrug design has not taken into consideration possible effects on human microbiota. The beneficial functions of bacteria could be stimulated by nanodrugs while negative effects on beneficial bacteria could cause risks to human health. Here, simulated intestinal fluid (IF) was optimized for culturing a human commensal and probiotic bacterial strain, Lactobacillus casei, to study the effects of medically relevant NPs­Ag and hyaluronic acid-coated Au NPs (HA-Au NPs)­in conditions pertinent to the gastrointestinal tract. When cultivated either aerobically or anaerobically, the specific growth rates of L. casei were ~0.2 h−1 in IF and ~0.4 h−1 in the standard medium of lactobacilli (MRS). Ag NPs inhibited the growth of L. casei in IF at lower concentrations (EC50 ~ 65 and 15 mg/L in aerobic and anaerobic conditions, respectively) than in MRS (EC50 > 100 mg/L), likely caused by differences in the composition of the two media and different intrinsic growth rates of bacteria in IF and MRS. Ag NP dissolution in IF and MRS did not explain the differences in growth inhibition, implying NP-specific effects. HA-Au NPs were not growth-inhibitory to L. casei up to 250 mg/L. Still, both NPs at sub-growth-inhibitory concentrations suppressed the expression of bacteriocin genes in L. casei, suggesting an inhibitory effect of NPs on the probiotic properties of L. casei, i.e., its competitiveness in microbial communities. However, HA-Au NPs did not appear to affect or even stimulated the immunomodulatory properties of L. casei in human intestinal epithelial cells. Thus, medically relevant NPs at low, sub-bacteriostatic levels can affect the metabolism of beneficial human bacteria and potentially induce changes in the microbiota and immune signaling.

Daphnia as a Sentinel Species for Environmental Health Protection: A Perspective on Biomonitoring and Bioremediation of Chemical Pollution.

Despite available technology and the knowledge that chemical pollution damages human and ecosystem health, chemical pollution remains rampant, ineffectively monitored, rarely prevented, and only occasionally mitigated. We present a framework that helps address current major challenges in the monitoring and assessment of chemical pollution by broadening the use of the sentinel species Daphnia as a diagnostic agent of water pollution. And where prevention has failed, we propose the application of Daphnia as a bioremediation agent to help reduce hazards from chemical mixtures in the environment. By applying "omics" technologies to Daphnia exposed to real-world ambient chemical mixtures, we show improvements at detecting bioactive components of chemical mixtures, determining the potential effects of untested chemicals within mixtures, and identifying targets of toxicity. We also show that using Daphnia strains that naturally adapted to chemical pollution as removal agents of ambient chemical mixtures can sustainably improve environmental health protection. Expanding the use of Daphnia beyond its current applications in regulatory toxicology has the potential to improve both the assessment and the remediation of environmental pollution.

Perfluorooctanoic acid alternatives hexafluoropropylene oxides exert male reproductive toxicity by disrupting blood-testis barrier.

As alternatives to perfluorooctanoic acid (PFOA), hexafluoropropylene oxide (HFPO) homologues, including hexafluoropropylene oxide dimer acid (HFPO-DA), hexafluoropropylene oxide trimer acid (HFPO-TA), and hexafluoropropylene oxide tetramer acid (HFPO-TeA), have attracted widespread attention recently due to their environmental ubiquity and high potential for bioaccumulation and toxicity. In the present study, a set of in vivo mouse and in vitro mouse testicular Sertoli TM4 cell experiments were employed to explore the male reproductive toxicity and underlying mechanisms of HFPO homologues on blood-testis barrier. Tissue and permeability analyses of mice testes after 28-day treatment with 5 mg/kg/day HFPO-DA or PFOA, or 0.05 mg/kg/day HFPO-TA or HFPO-TeA indicated that there was an increase in the degradation of TJ protein occludin in mice with a disrupted blood-testis barrier (BTB). Following exposure to 100 µM HFPO-DA, HFPO-TA or 10 µM PFOA, HFPO-TeA, transepithelial electrical resistance measurements of TM4 cells also indicated BTB disruption. Additionally, as a result of the exposure, matrix metalloproteinase-9 expression was enhanced through activation of p38 MAPK, which promoted the degradation of occludin. On the whole, the results indicated HFPO homologues and PFOA induced BTB disruption through upregulation of p-p38/p38 MAPK/MMP-9 pathway, which promoted the degradation of TJ protein occludin and caused the disruption of TJ.

Functions and performance of ionic liquids in enhancing electrocatalytic hydrogen evolution reactions: a comprehensive review.

As a green and renewable energy source, hydrogen can be produced by the electrolysis of water via the hydrogen evolution reaction (HER). Nevertheless, this method requires efficient and low-cost electro-catalysts to improve hydrogen production efficiency. Ionic liquids (ILs), with a unique combination of such superior properties as low vapor pressure, high electrical conductivity, high electrochemical stability, and a wide variety of functional groups, have found applications in electrochemical systems designed for efficient HER. Herein, we provide a comprehensive and updated review on the functions and performance of ILs used in electrochemical systems to enhance the HER. As the name suggests, ILs have been employed either as electrolytes by themselves, or as electrolyte additives. They also played many functional roles in the synthesis of HER electrocatalysts, including as the synthesis reaction solvent, reaction precursor as well as single/dual ion sources, binder and structure-directing agents of the catalysts. With the assistance of ILs, HER efficiency of electrocatalysts was improved significantly, resulting in decreased overpotentials in the range of 16-385 mV @ 10 mA cm-2 and increased Tafel slopes in the range of 30-210 mV dec-1. Lastly, the problems and challenges of ILs in electrocatalytic water electrolysis and HER are also discussed and their prospects considered.