The effect and mechanism of variable particle size microplastics and levofloxacin on the neurotoxicity of Rana nigromaculata based on the microorganism-intestine-brain axis.

Microplastics (MPs) usually appear in the aquatic environment as complex pollutants in combination with other environmental pollutants, such as levofloxacin (LVFX). After a 45-day exposure to LVFX and MPs with different particle sizes at environmental levels, LVFX was neurotoxic to Rana nigromaculata tadpoles. The order of the effects of the exposure treatment on tadpole behavior was: LVFX-MP3>LVFX-MP1>LVFX-MP2 ≥ LVFX. Results of transcriptome analysis of tadpole brain tissue showed that LVFX in combination with 0.10 and 10.00 µm MP interferes with the nervous system through the cell adhesion molecules pathway. Interestingly, the order of effects of the co-exposure on oxidative stress in the intestine was inconsistent with that of tadpole behavior. We found that Paraacteroides might be a microplastic indicator species for the gut microbiota of aquatic organisms. The results of the targeted metabolism of neurotransmitters in the intestine suggest that in the LVFX-MP2 treatment, LVFX alleviated the intestinal microbiota disorder caused by 1.00 µm MP, by regulating intestinal microbiota participating in the TCA cycle VI and gluconeogenesis and tetrapyrrole biosynthesis I, while downregulating Met and Orn, and upregulating 5HIAA, thereby easing the neurotoxicity to tadpoles exposed to LVFX-MP2. This work is of great significance for the comprehensive assessment of the aquatic ecological risks of microplastics-antibiotic compound pollutants.

Vitamin D modulates disordered lipid metabolism in zebrafish (Danio rerio) liver caused by exposure to polystyrene nanoplastics.

In this study, zebrafish (Danio rerio) were exposed to polystyrene nanoplastics (PS-NPs, 80 nm) at 0, 15, or 150 µg/L for 21 days and supplied with a low or high vitamin D (VD) diet (280 or 2800 IU/kg, respectively, indicated by - or +) to determine whether and how VD can regulate lipid metabolism disorder induced by PS-NPs. Six groups were created according to the PS-NP concentration and VD diet status: 0-, 0+, 15-, 15+,150-, and 150 +. Transmission electron microscopy showed that PS-NPs accumulated in the livers of zebrafish, which led to large numbers of vacuoles and lipid droplets in liver cell matrices; this accumulation was most prominent in the 150- group, wherein the number of lipid droplets increased significantly by 136.36%. However, the number of lipid droplets decreased significantly by 76.92% in the 150+ group compared with the 150- group. An examination of additional biochemical indicators showed that the high VD diet partially reversed the increases in the triglyceride and total cholesterol contents induced by PS-NPs (e.g., triglycerides decreased by 58.52% in the 150+ group, and total cholesterol decreased by 44.64% in the 15+ group), and regulated lipid metabolism disorder mainly by inhibiting lipid biosynthesis. Untargeted lipidomics analysis showed that exposure to PS-NPs was associated mainly with changes in the lipid molecular content related to cell membrane function and lipid biosynthesis and that the high VD diet reduced the content of lipid molecules related to lipid biosynthesis, effectively alleviating cell membrane damage and lipid accumulation. These findings highlight the potential of VD to alleviate lipid metabolism disorder caused by PS-NP exposure, thereby providing new insights into how the toxic effects of NPs on aquatic organisms could be reduced.

Vitamin D modulation of brain-gut-virome disorder caused by polystyrene nanoplastics exposure in zebrafish (Danio rerio).

BACKGROUND: Many studies have investigated how nanoplastics (NPs) exposure mediates nerve and intestinal toxicity through a dysregulated brain-gut axis interaction, but there are few studies aimed at alleviating those effects. To determine whether and how vitamin D can impact that toxicity, fish were supplemented with a vitamin D-low diet and vitamin D-high diet. RESULTS: Transmission electron microscopy (TEM) showed that polystyrene nanoplastics (PS-NPs) accumulated in zebrafish brain and intestine, resulting in brain blood-brain barrier basement membrane damage and the vacuolization of intestinal goblet cells and mitochondria. A high concentration of vitamin D reduced the accumulation of PS-NPs in zebrafish brain tissues by 20% and intestinal tissues by 58.8% and 52.2%, respectively, and alleviated the pathological damage induced by PS-NPs. Adequate vitamin D significantly increased the content of serotonin (5-HT) and reduced the anxiety-like behavior of zebrafish caused by PS-NPs exposure. Virus metagenome showed that PS-NPs exposure affected the composition and abundance of zebrafish intestinal viruses. Differentially expressed viruses in the vitamin D-low and vitamin D-high group affected the secretion of brain neurotransmitters in zebrafish. Virus AF191073 was negatively correlated with neurotransmitter 5-HT, whereas KT319643 was positively correlated with malondialdehyde (MDA) content and the expression of cytochrome 1a1 (cyp1a1) and cytochrome 1b1 (cyp1b1) in the intestine. This suggests that AF191073 and KT319643 may be key viruses that mediate the vitamin D reduction in neurotoxicity and immunotoxicity induced by PS-NPs. CONCLUSION: Vitamin D can alleviate neurotoxicity and immunotoxicity induced by PS-NPs exposure by directionally altering the gut virome. These findings highlight the potential of vitamin D to alleviate the brain-gut-virome disorder caused by PS-NPs exposure and suggest potential therapeutic strategies to reduce the risk of NPs toxicity in aquaculture, that is, adding adequate vitamin D to diet. Video Abstract.

Hydrogen Nanobubble Water: A Good Assistant for Improving the Water Environment and Agricultural Production.

Hydrogen nanobubble water (HNW) is an emerging technique in the field of environment and agriculture that is attracting more attention due to its eminent characteristic. HNW exhibits a higher solution stagnation rate with a longer existence in water than molecular hydrogen, which ensures its practical usage. In this Viewpoint, the properties and applications of HNW are discussed. HNW, acting as an antioxidant, effectively eliminates reactive oxygen species and counteracts Cu and Cd stress; HNW also increases crop growth, enhances crops quality, and improves transportation and storage processes. On the basis of the advantages of HNW, we recommend focusing on the potential functions of HNW and broadening its wider applications in environment and agriculture.

Size-dependent long-term weathering converting floating polypropylene macro- and microplastics into nanoplastics in coastal seawater environments.

In this study, we systematically developed the long-term photoaging behavior of different-sized polypropylene (PP) floating plastic wastes in a coastal seawater environment. After 68 d of laboratory accelerated UV irradiation, the PP plastic particle size decreased by 99.3 ± 0.15%, and nanoplastics (average size: 435 ± 250 nm) were produced with a maximum yield of 57.9%, evidencing that natural sunlight irradiation-induced long-term photoaging ultimately converts floating plastic waste in marine environments into micro- and nanoplastics. Subsequently, when comparing the photoaging rate of different sized PP plastics in coastal seawater, we discovered that large sized PP plastics (1000-2000 and 5000-7000 µm) showed a lower photoaging rate than that of small sized PP plastic debris (0-150 and 300-500 µm), with the decrease rate of plastic crystallinity as follow: 0-150 µm (2.01 d-1) > 300-500 µm (1.25 d-1) > 1000-2000 µm (0.780 d-1) and 5000-7000 µm (0.900 d-1). This result can be attributed to the small size PP plastics producing more reactive oxygen species (ROS) species, with the formation capacity of hydroxyl radical •OH as follows: 0-150 µm (6.46 × 10-15 M) > 300-500 µm (4.87 × 10-15 M) > 500-1000 (3.61 × 10-15 M) and 5000-7000 µm (3.73 × 10-15 M). The findings obtained in this study offer a new perspective on the formation and ecological risks of PP nanoplastics in current coastal seawater environments.

Insight into the binding model of per- and polyfluoroalkyl substances to proteins and membranes.

Legacy per- and polyfluoroalkyl substances (PFASs) have elicited much concern because of their ubiquitous distribution in the environment and the potential hazards they pose to wildlife and human health. Although an increasing number of effective PFAS alternatives are available in the market, these alternatives bring new challenges. This paper comprehensively reviews how PFASs bind to transport proteins (e.g., serum albumin, liver fatty acid transport proteins and organic acid transporters), nuclear receptors (e.g., peroxisome proliferator activated receptors, thyroid hormone receptors and reproductive hormone receptors) and membranes (e.g., cell membrane and mitochondrial membrane). Briefly, the hydrophobic fluorinated carbon chains of PFASs occupy the binding cavities of the target proteins, and the acid groups of PFASs form hydrogen bonds with amino acid residues. Various structural features of PFAS alternatives such as chlorine atom substitution, oxygen atom insertion and a branched structure, introduce variations in their chain length and hydrophobicity, which potentially change the affinity of PFAS alternatives for endogenous proteins. The toxic effects and mechanisms of action of legacy PFASs can be demonstrated and compared with their alternatives using binding models. In future studies, in vitro experiments and in silico quantitative structure-activity relationship modeling should be better integrated to allow more reliable toxicity predictions for both legacy and alternative PFASs.

Study effect and mechanism of ofloxacin and levofloxacin on development of Rana nigromaculata tadpoles based on the hypothalamus-pituitary-thyroid axis.

Excessive antibiotics transferred into the aquatic environment may affect the development of amphibians. Previous studies on the aquatic ecological risk of ofloxacin generally ignored its enantiomers. The purpose of this study was to compare the effects and mechanisms of ofloxacin (OFL) and levofloxacin (LEV) on the early development of Rana nigromaculata. After 28-day exposure at environmental levels, we found that LEV exerted more severe inhibitory effects on the development of tadpoles than OFL. According to the enrichment results of differentially expressed genes in the LEV and OFL treatments, LEV and OFL had different effects on the thyroid development of tadpoles. dio2 and trh were affected by the regulation of dexofloxacin instead of LEV. At the protein level, LEV was the main component that affected thyroid development-related protein, while dexofloxacin in OFL had little effect on thyroid development. Furthermore, molecular docking results further confirmed that LEV was a major component affecting thyroid development-related proteins, including DIO and TSH. In summary, OFL and LEV regulated the thyroid axis by differential binding to DIO and TSH proteins, thereby exerting differential effects on the thyroid development of tadpoles. Our research is of great significance for comprehensive assessment of chiral antibiotics aquatic ecological risk.

Chlorothalonil induces obesity in mice by regulating host gut microbiota and bile acids metabolism via FXR pathways.

As the most commonly used organochlorine pesticide nowadays, chlorothalonil (CHI), is ubiquitous in a natural environment and poses many adverse effects to organisms. Unfortunately, the toxicity mechanisms of CHI have not been clarified yet. This study found that the CHI based on ADI level could induce obesity in mice. In addition, CHI could induce an imbalance in the gut microbiota of mice. Furthermore, the results of the antibiotic treatment and gut microbiota transplantation experiments showed that the CHI could induce obesity in mice in a gut microbiota-dependent manner. Based on the results of targeted metabolomics and gene expression analysis, CHI could disturb the bile acids (BAs) metabolism of mice, causing the inhibition of the signal response of BAs receptor FXR and leading to glycolipid metabolism disorders in liver and epiWAT of mice. The administration of FXR agonist GW4064 and CDCA could significantly improve the CHI-induced obesity in mice. In conclusion, CHI was found to induce obesity in mice by regulating the gut microbiota and BAs metabolism via the FXR signaling pathway. This study provides evidence linking the gut microbiota and pesticides exposure with the progression of obesity, demonstrating the key role of gut microbiota in the toxic effects of pesticides.

Integrated assessment of land-to-river Cd fluxes and riverine Cd loads using SWAT-HM to guide management strategies.

In 2011, China invested US$9.8 billion to combat the severe heavy metal pollution in the Xiang River basin (XRB), aiming to reduce 50% of the 2008 industrial metal emissions by 2015. However, river pollution mitigation requires a holistic accounting of both point and diffuse sources, yet the detailed land-to-river metal fluxes in the XRB remain unclear. Here, by combining emissions inventories with the SWAT-HM model, we quantified the land-to-river cadmium (Cd) fluxes and riverine Cd loads across the XRB from 2000 to 2015. The model was validated against long-term historical observations of monthly streamflow and sediment load and Cd concentrations at 42, 11, and 10 gauges, respectively. The analysis of the simulation results showed that the soil erosion flux dominated the Cd exports (23.56-80.14 Mg yr-1). The industrial point flux decreased by 85.5% from 20.84 Mg in 2000 to 3.02 Mg in 2015. Of all the Cd inputs, approximately 54.9% (37.40 Mg yr-1) was finally drained into Dongting Lake; the remaining 45.1% (30.79 Mg yr-1) was deposited within the XRB, increasing the Cd concentration in riverbed sediment. Furthermore, in XRB's 5-order river network, the Cd concentrations in small streams (1st order and 2nd order) showed larger variability due to their low dilution capacity and intense Cd inputs. Our findings highlight the need for multi-path transport modeling to guide future management strategies and better monitoring schemes to restore the small polluted streams.

Study effect and mechanism of levofloxacin on the neurotoxicity of Rana nigromaculata tadpoles exposed to imidacloprid based on the microbe-gut-brain axis.

Aquatic organisms may be simultaneously exposed to antibiotics and pesticides. After levofloxacin (LVFX), imidacloprid (IMI) exposure and co-exposure at environmental levels, we found LVFX and IMI had antagonistic effect on the neurotoxicity of tadpoles. IMI-induced neurotoxicity on tadpoles can be explained by oxidative stress and hormone levels in some degree. By regulating ornithine, l-asparagine, putrescine and tryptamine in the intestine, LVFX affected glutathione metabolism, arginine and proline metabolism, alanine, aspartate and glutamate metabolism, tyrosine metabolism and aminoacyl tRNA biosynthesis, so then eased the neurotoxicity caused by IMI. More interestingly, Fusobacteriota and Cetobacterium might play an important role on easing the neurotoxicity caused by IMI. In addition, LVFX might have a laxation effect on the increased relative abundance of Bacteroidota caused by IMI. In conclusion, IMI not only affected oxidative stress and hormone levels in the brain, but also affected the synthesis of neurotransmitters in the intestine by regulating intestinal microbiota. In LVFX and IMI co-exposed groups, LVFX alleviated the neurotoxicity caused by IMI through regulating the intestinal microbiota, showing as an antagonistic effect. Our results provided a new perspective for aquatic ecological risk assessment under co-exposure of antibiotics and pesticides.

Paternal Inheritance Is an Important, but Overlooked, Factor Affecting the Adverse Effects of Microplastics and Nanoplastics on Subsequent Generations.

Microplastics (MPs) and nanoplastics (NPs) are widely detected in food and the human environment. More studies have begun to pay attention to the influence of MPs and NPs on genetics; in particular, exposure of paternal generation to MPs and NPs on epigenetic inheritance and the offspring of animal models have attracted considerable interest. In this Viewpoint, we mainly discuss the suggestion that reproductive genetic changes in the male parent have the potential to be transferred to the offspring and illustrate how MPs and NPs in the father tissues are distributed in later generations. We provide a systematic understanding of the potential health hazards of paternal exposure to MPs and NPs to subsequent generations and put forth recommendations about the epigenetic effects for future research on public health and food safety.

Wastewater treatment plants act as essential sources of microplastic formation in aquatic environments: A critical review.

According to extensive in situ investigations, the microplastics (MPs) determined in current wastewater treatment plants (WWTPs) are mostly aged, with roughened surfaces and varied types of oxygen-containing functional groups (i.e., carbonyl and hydroxyl). However, the formation mechanism of aged MPs in WWTPs is still unclear. This paper systematically reviewed MP fragmentation and generation mechanisms in WWTPs at different treatment stages. The results highlight that MPs are prone to undergo physical abrasion, biofouling, and chemical oxidation-associated weathering in WWTPs at different treatment stages and can be further decomposed into smaller secondary MPs, including in nanoplastics (less than 1000 nm or 100 nm in size), suggesting that WWTPs can act as a formation source for MPs in aquatic environments. Sand associated mechanical crashes in the primary stage, microbes in active sewage sludge-related biodegradation in the secondary stage, and oxidant-relevant chemical oxidation processes (light photons, Cl2, and O3) in the tertiary stage are the dominant causes of MP formation in WWTPs. For MP formation mechanisms in WWTPs, external environmental forces (shear and stress forces, UV radiation, and biodegradation) can first induce plastic chain scission, destroy the plastic molecular arrangement, and create abundant pores and cracks on the MP surface. Then, the physicochemical properties (modulus of elasticity, tensile strength and elongation at break) of MPs shift consequently and finally breakdown into smaller secondary MPs or nanoscale plastics. Overall, this review provides new insights to better understand the formation mechanism, occurrence, fate, and adverse effects of aged microplastics/nanoplastics in current WWTPs.

Parental exposure to propiconazole at environmentally relevant concentrations induces thyroid and metabolism disruption in zebrafish (Danio rerio) offspring: An in vivo, in silico and in vitro study.

Propiconazole is used against fungal growth in agriculture and is released into the environment, but is a potential health threat to aquatic organisms. Propiconazole induces a generational effect on zebrafish, although the toxic mechanisms involved have not been described. The aim of this study was to investigate the potential mechanisms of abnormal offspring development after propiconazole exposure in zebrafish parents. Zebrafish were exposed to propiconazole at environmentally realistic concentrations (0.1, 5, and 250 µg/L) for 100 days and their offspring were grown in control solution for further study. Heart rate, hatching rate, and body length of hatched offspring were reduced. An increase in triiodothyronine (T3) content and the T3/T4 (tetraiodothyronine) ratio was observed, indicating disruption of thyroid hormones. Increased protein level of transthyretin (TTR) in vivo was consistent with the in silico molecular docking results and T4 competitive binding in vitro assay, suggests higher binding affinity between propiconazole and TTR, more than with T4. Increased expression of genes related to the hypothalamus-pituitary-thyroid (HPT) axis and altered metabolite levels may have affected offspring development. These findings emphasizes that propiconazole, even on indirect exposure, represents health and environmental risk that should not be ignored.

Identification priority source of soil heavy metals pollution based on source-specific ecological and human health risk analysis in a typical smelting and mining region of South China.

An in-depth understanding of the ecological and health risks posed by heavy metals originating from various pollution sources is critical for foresighted soil-quality management. Based on 220 grid samples (2 × 2 km) analyzed for eight heavy metals (Cd, Hg, As, Pb, Cr, Ni, Cu, and Zn) in the Chenshui (CS) watershed of Hunan Province, China, we applied an integrated approach for identifying and apportioning pollution sources of soil heavy metals and exploring their source-specific pollution risks. This approach consists of three sequential steps: (1) source identification by combining the positive matrix factorization model with geostatistical analysis; (2) quantification of ecological, carcinogenic, and non-carcinogenic risks in a source-specific manner; (3) prioritization of sources in a holistic manner, considering both ecological risks and human health risks. Cd (68.0%) and Hg (13.3%) dominated the ecological risk in terms of ecological risk index; As dominated the non-carcinogenic health risk in terms of total hazard index (THI; adults: 84.8%, children: 84.7%) and the carcinogenic health risk in terms of total carcinogenic risk index (TCRI; adults: 69.0%, children: 68.8%). Among three exposure routes, oral ingestion (89.4-95.2%) was the predominant route for both adults and children. Compared with adults (THI = 0.41, TCRI = 7.01E-05), children (THI = 2.81, TCRI = 1.22E-04) had greater non-carcinogenic and carcinogenic risks. Four sources (F1-4) were identified for the CS watershed: atmospheric deposition related to coal-burning and traffic emissions (F1, 18.0%), natural sources from parent materials (F2, 34.3%), non-ferrous mining and smelting industry (F3, 37.9%), and historical arsenic-related activity (F4, 9.8%). The F3 source contributed the largest (45.2%) to the ecological risks, and the F4 source was the predominant contributor to non-carcinogenic (52.4%) and carcinogenic (64.6%) risks. The results highlight the importance of considering legacy As pollution from abandoned industries when developing risk reduction strategies in this region. The proposed methodology for source and risk identification and apportionment formulates the multidimensional concerns of pollution and the various associated risks into a tangible decision-making process to support soil pollution control.

Critical effect of biodegradation on long-term microplastic weathering in sediment environments: A systematic review.

Microplastic (MP) pollution in global sediment has been intensely studied and recognized as the ultimate sink for residual MPs in terrestrial and aquatic ecosystems. During MP long-term retention in sediments, plastic-degrading bacteria (i.e., Flavobacteriaceae, Bacillus, Rhodobacteraceae, and Desulfobacteraceae) can utilize those MPs as their carbon and energy sources through enzyme (hydrolase and oxidoreductase) reactions, which further alter or transform high molecular weight MP polymers into lower molecular weight biodegradation byproducts (i.e., monomers and oligomers) and release toxic additives. In other words, MPs can act as durable substrates for plastic-degrading bacteria in sediments. However, to date, the biodegradation rates of MPs in sediment environments are still poorly understood due to their limited degradation efficiency. Herein, we review the enzyme-induced biodegradation processes of MPs in sediment environments, which is important for accessing the alteration of MP properties and their potential ecological risks after undergoing long-term weathering processes. In addition, the factors associated with the MP properties (polymer type, molecular weight, crystallinity, and hydrophobicity) and sediment conditions (sediment type, temperature, pH, salinity, and oxygen content) that influence plastic degradation processes are also reviewed. The mechanisms may relate to the MP properties and sediment conditions that can influence microbial abundance, enzyme concentrations, and enzyme activities, thus altering MP biodegradation ratios. We anticipate that the observations reviewed in this study will pose a new issue to better understand the formation process, fate, and potential ecological risks associated with aged MPs in sediment environments.

Imazalil and its metabolite imazalil-M caused developmental toxicity in zebrafish (Danio rerio) embryos via cell apoptosis mediated by metabolic disorders.

Imazalil (IMZ) is a highly effective fungicide employed in crop production. It has been consistently detected in aquatic environments. The main environmental metabolite of IMZ is imazalil-M (IMZ-M). Limited studies have focused on the toxicity of IMZ and IMZ-M in aquatic organisms. This study systematically evaluated the developmental toxicity of IMZ and IMZ-M on zebrafish (Danio rerio) embryos and explored the potential mechanisms involved. The results showed that IMZ and IMZ-M caused developmental toxicity, characterized by decreased heart rate, hatching inhibition, and pericardial cyst in zebrafish embryos. Subsequently, acridine orange (AO) staining revealed cell apoptosis in the area around the heart regions of zebrafish larvae. Besides, the expression levels of apoptosis-related genes also varied significantly. Furthermore, 1H NMR-based metabolomics analysis showed that IMZ and IMZ-M exposure could induce metabolic profiles disorder in zebrafish larvae. Importantly, zebrafish exposure to IMZ and IMZ-M significantly affected the metabolism of branched - chain amino acids, energy, and ketone bodies, which are related to cell apoptosis. Overall, the toxicity of IMZ and IMZ-M in zebrafish embryos and larvae was characterized, suggesting a theoretical basis for the potential environmental risks of IMZ and its metabolite IMZ-M on non-target organisms.

Polystyrene Nanoplastics Toxicity to Zebrafish: Dysregulation of the Brain-Intestine-Microbiota Axis.

In animal species, the brain-gut axis is a complex bidirectional network between the gastrointestinal (GI) tract and the central nervous system (CNS) consisting of numerous microbial, immune, neuronal, and hormonal pathways that profoundly impact organism development and health. Although nanoplastics (NPs) have been shown to cause intestinal and neural toxicity in fish, the role of the neurotransmitter and intestinal microbiota interactions in the underlying mechanism of toxicity, particularly at environmentally relevant contaminant concentrations, remains unknown. Here, the effect of 44 nm polystyrene nanoplastics (PS-NPs) on the brain-intestine-microbe axis and embryo-larval development in zebrafish (Danio rerio) was investigated. Exposure to 1, 10, and 100 µg/L PS-NPs for 30 days inhibited growth and adversely affected inflammatory responses and intestinal permeability. Targeted metabolomics analysis revealed an alteration of 42 metabolites involved in neurotransmission. The content of 3,4-dihydroxyphenylacetic acid (DOPAC; dopamine metabolite formed by monoamine oxidase activity) was significantly decreased in a dose-dependent manner after PS-NP exposure. Changes in the 14 metabolites correlated with changes to 3 microbial groups, including Proteobacteria, Firmicutes, and Bacteroidetes, as compared to the control group. A significant relationship between Firmicutes and homovanillic acid (0.466, Pearson correlation coefficient) was evident. Eight altered metabolites (l-glutamine (Gln), 5-hydroxyindoleacetic acid (5-HIAA), serotonin, 5-hydroxytryptophan (5-HTP), l-cysteine (Cys), l-glutamic acid (Glu), norepinephrine (NE), and l-tryptophan (l-Trp)) had a negative relationship with Proteobacteria although histamine (His) and acetylcholine chloride (ACh chloride) levels were positively correlated with Proteobacteria. An Associated Network analysis showed that Firmicutes and Bacteroidetes were highly correlated (0.969). Furthermore, PS-NPs accumulated in the gastrointestinal tract of offspring and impaired development of F1 (2 h post-fertilization) embryos, including reduced spontaneous movements, hatching rate, and length. This demonstration of transgenerational deficits is of particular concern. These findings suggest that PS-NPs cause intestinal inflammation, growth inhibition, and restricted development of zebrafish, which are strongly linked to the disrupted regulation within the brain-intestine-microbiota axis. Our study provides insights into how xenobiotics can disrupt the regulation of brain-intestine-microbiota and suggests that these end points should be taken into account when assessing environmental health risks of PS-NPs to aquatic organisms.

A comparative study on aggregation and sedimentation of natural goethite and artificial Fe3O4 nanoparticles in synthetic and natural waters based on extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory and molecular dynamics simulations.

Natural iron oxides nanomaterials have important roles in biogeochemical processes. In this study, the effects of pH, natural organic matter, and cations on aggregation and sedimentation of natural goethite and artificial Fe3O4 nanoparticles in water were investigated to learn more about the environmental behaviors of engineered and natural nanomaterials and how they differ. In addition, a novel extended DLVO theory that considered steric, gravitational, and magnetic attraction forces concurrently was specifically developed to provide mechanisms explanations. Specifically, Fe3O4 NPs were more likely than bulk goethite to aggregate (because of magnetic attraction interactions) at low HA concentrations and disperse at high HA concentrations. Besides, goethite was less prone to settle with the same concentration of NaCl than Fe3O4 NPs, but the opposite trend was found for the same concentration of CaCl2 because of the difference in maximum net energy (barrier) and strong Ca2+ bridging effectiveness of goethite in CaCl2 solution. Statistical models were established to evaluate colloidal stability of the particles. XPS and molecular dynamics simulation results suggested that ions were adsorbed onto particles via ionic polarization and that the binding free energies at high coverage followed the order Ca2+ > Na+ > Cl- and presence of cation bridging between particles.

Insights into the mechanisms of organic pollutant toxicity to earthworms: Advances and perspectives.

Earthworms play positive ecological roles in soil formation, structure, and fertility, environmental protection, and terrestrial food chains. For this review, we searched the Web of Science database for articles published from 2011 to 2021 using the keywords "toxic" and "earthworm" and retrieved 632 publications. From the perspective of bibliometric analysis, we conducted a co-occurrence network analysis using the keywords "toxic" and "earthworm" to identify the most and least reported topics. "Eisenia fetida," "bioaccumulation," "heavy metals," "oxidative stress," and "pesticides" were the most common terms, and "microbial community," "bacteria," "PFOS," "bioaugmentation," "potentially toxic elements," "celomic fluid," "neurotoxicity," "joint toxicity," "apoptosis," and "nanoparticles" were uncommon terms. Additionally, in this review we highlight the main routes of organic pollutant entry into soil, and discuss the adverse effects on the soil ecosystem. We then systematically review the mechanisms underlying organic pollutant toxicity to earthworms, including oxidative stress, energy and lipid metabolism disturbances, neurological toxicity, intestinal inflammation and injury, gut microbiota dysbiosis, and reproductive toxicity. We conclude by discussing future research perspectives, focusing on environmentally relevant concentrations and conditions, novel data processing approaches, technologies, and detoxification and mitigation methods. This review has implications for soil management in the context of environmental pollution.

Combined toxicity of chlorpyrifos, abamectin, imidacloprid, and acetamiprid on earthworms (Eisenia fetida).

Mixed pesticides have been broadly used in agriculture. However, assessing the combined effects of pesticides in the environment is essential for potential risk assessment, though the task is far from complete. Median lethal concentrations of pesticides as well as acetylcholinesterase (AChE) levels and cellulose activities were measured in earthworms (Eisenia fetida) individually and jointly exposed to pesticides imidacloprid (IMI), acetamiprid (ACE), chlorpyrifos (CRF), and abamectin (ABM)). A 3:1 mixture of CRF and IMI had additive effects, while a 3:1 mixture of CRF and ACE had synergic effects. The joint effects of ABM with IMI or with ACE were synergistic. As CRF concentration increased, AChE activities were significantly decreased. For high concentrations of IMI, AChE activities under combined CRF and IMI applications were significantly inhibited following increased exposure time. Moreover, the cellulase activities under combined applications of CRF with IMI or with ACE had similar effects. This study provides basic data for scientifically evaluating the environmental risk and safety of combined uses of pesticides.