North-Eastern Brazil saw intensive application of the insecticide pyriproxyfen (PPF) during the microcephaly outbreak caused by the Zika virus (ZIKV). ZIKV requires the neural RNA-binding protein Musashi-1 to replicate. Thyroid hormone (TH) represses MSI1. PPF is a suspected TH disruptor. We hypothesized that co-exposure to the main metabolite of PPF, 4′–OH–PPF, could exacerbate ZIKV effects through increased MSI1 expression. Exposing an in vivo reporter model, Xenopus laevis, to 4′–OH–PPF decreased TH signaling and increased msi1 mRNA and protein, confirming TH-antagonistic properties. Next, we investigated the metabolite's effects on mouse subventricular zone-derived neural stem cells (NSCs). Exposure to 4′–OH–PPF dose-dependently reduced neuroprogenitor proliferation and dysregulated genes implicated in neurogliogenesis. The highest dose induced Msi1 mRNA and protein, increasing cell apoptosis and the ratio of neurons to glial cells. Given these effects of the metabolite alone, we considered if combined infection with ZIKV worsened neurogenic events. Only at the fourth and last day of incubation did co-exposure of 4′–OH–PPF and ZIKV decrease viral replication, but viral RNA copies stayed within the same order of magnitude. Intracellular RNA content of NSCs was decreased in the combined presence of 4′–OH–PPF and ZIKV, suggesting a synergistic block of transcriptional machinery. Seven out of 12 tested key genes in TH signaling and neuroglial commitment were dysregulated by co-exposure, of which four were unaltered when exposed to 4′–OH–PPF alone. We conclude that 4′–OH–PPF is an active TH-antagonist, altering NSC processes known to underlie correct cortical development. A combination of the TH-disrupting metabolite and ZIKV could aggravate the microcephaly phenotype.

Riverine nitrogen loading to the continental shelf sea is important for terrestrial–marine linkage and global nitrogen cycling and leads to serious marine environmental problems. The budget and cycle of riverine nitrogen over the continental shelf in the East China Sea (ECS) are unknown. Using the tracking technique within a physical–biological coupled model, we quantified the nitrogen budgets of riverine dissolved inorganic nitrogen (DIN) and particulate organic nitrogen (PON) over seasonal to annual scales in the ECS, especially from the Changjiang River, which plays a dominant role in riverine nitrogen input. The horizontal distributions of the Changjiang DIN and PON generally followed the Changjiang diluted water and coastal currents and were affected by stratification in the vertical direction. Their inventory variations were dominated by biological fluxes and modulated by physical ones, and changed most dramatically in the inner shelf among three subregions. Less than half of DIN were converted to PON with most of the rest leaving the ECS through lateral transport pathways, among which the flux through the Tsushima Strait was dominant. With the increasing loading of the Changjiang DIN flux from the 1980s–2010s, lateral transports rather than PON production increased due to limited primary production. Approximately 60 % of the produced PON exported to the sediment and 34 % went to the Tsushima Strait. According to the export production, the DIN from the Changjiang River contributed 12–42 % to the ECS carbon sequestration.

In soils, the presence of clinically relevant bacteria carrying ARGs, including extended-spectrum β-lactamase- and plasmid-mediated AmpC β-lactamase-encoding genes, is an underestimated public health problem that requires more attention. For this investigation, 300 samples from agricultural and non-agricultural soils were used to obtain 41 MDR E. coli isolates, standing out the resistance to β-lactams, fluoroquinolones and colistin. Virulence genes related to diarrheagenic E. coli and extraintestinal pathogenic E. coli were detected. Several ARGs were found, highlighting the presence of at least one β-lactamase-encoding gene (blaTEM, blaCMY, blaSHV, blaOXA₋₁₋ₗᵢₖₑ, blaCTX₋M₋₂, and/or blaCTX₋M₋₁₅) in each isolate. Among the fluoroquinolone-resistant E. coli isolates, the plasmid-mediated quinolone resistance genes (qnrB and oqxA) and substitutions in the quinolone resistance-determining regions were detected. Some isolates were resistant to colistin (MICs of 4–8 mg/L) and, although no mcr-like gene was detected, substitutions in the two-component systems involving PhoP/PhoQ and PmrA/PmrB were found. Furthermore, the E. coli isolates presented plasmids and class 1 integrons, the last one detected in all isolates. The ARGs blaTEM, aadA and dfrA and the lpfA virulence-associated gene presented statistically significant differences (P < 0.05) in agricultural soils, while the blaOXA₋₁₋ₗᵢₖₑ gene presented a statistically significant difference in non-agricultural soils. Thirty-eight sequence types (STs) were identified among the isolates, spotlighting the 20 different STs that carried blaCMY and blaCTX₋M₋ₜyₚₑ genes and those commonly reported in infections worldwide. The occurrence of virulent, multidrug- and colistin-resistant E. coli isolates in soils could lead to contamination of surrounding environments and food, increasing the risk of human and animal exposure. Therefore, this study contributes to a better understanding of E. coli in soils and reinforces the importance of the One Health approach to antimicrobial resistance surveillance.

Silver nanomaterials (AgNMs) are broadly used and among the most studied nanomaterials. The underlying molecular mechanisms (e.g. protein and metabolite response) that precede phenotypical effects have been assessed to a much lesser extent. In this paper, we assess differentially expressed proteins (DEPs) and metabolites (DEMs) by high-throughput (HTP) techniques (HPLC-MS/MS with tandem mass tags, reversed-phase (RP) and hydrophilic interaction liquid chromatography (HILIC) with mass spectrometric detection). In a time series (0, 7, 14 days), the standard soil model Enchytraeus crypticus was exposed to AgNM300K and AgNO₃ at the reproduction EC20 and EC50. The impact on proteins/metabolites was clearly larger after 14 days. NM300K caused more upregulated DEPs/DEMs, more so at the EC20, whereas AgNO₃ caused a dose response increase of DEPs/DEMs. Similar pathways were activated, although often via opposite regulation (up vs down) of DEPs, hence, dissimilar mechanisms underlie the apical observed impact. Affected pathways included e.g. energy and lipid metabolism and oxidative stress. Uniquely affected by AgNO₃ was catalase, malate dehydrogenase and ATP-citrate synthase, and heat shock proteins (HSP70) and ferritin were affected by AgNM300K. The gene expression-based data in Adverse Outcome Pathway was confirmed and additional key events added, e.g. regulation of catalase and heat shock proteins were confirmed to be included. Finally, we observed (as we have seen before) that lower concentration of the NM caused higher biological impact. Data was deposited to ProteomeXchange, identifier PXD024444.

In this study, Gymnodinium aeruginosum was exposed to polystyrene (PS) and polymethyl methacrylate (PMMA) of three particle sizes (0.1 μm, 1.0 μm and 100 μm) and two concentrations (10 mg/L and 75 mg/L) for 96 h. The density of algae cells, the endpoints that reactive oxygen species (ROS), total protein (TP), malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT), scanning and transmission electron microscopy (SEM and TEM) were used to explore the toxicity mechanism to the microalgae. At a concentration of 75 mg/L, the 96 h inhibition ratios (IR) with particle sizes of 0.1 μm, 1.0 μm and 100 μm on G. aeruginosum were 55.9%, 63.7% and 6.0% for PS, respectively, and 3.0%, 4.1% and ‐0.6% for PMMA, respectively. The most significant changes in ROS, TP, MDA, SOD and CAT were observed at 75 mg/L 1.0 μm of PS when treated for 96 h. When exposed to nanoplastics (NPs) and microplastics (MPs), the algae cells were damaged, and the antioxidant system was activated. Extracellular polymeric substance (EPS) could help to detoxify the algae. In general, PS was more toxic than PMMA. The toxicity of small MNPs (0.1 μm and 1.0 μm) was related to the concentrations, while large MNPs (100 μm) did not.

Perfluorinated compounds (PFCs), as emerging persistent pollutants, can exist for a long time in the environment due to their high stability. PFCs have been detected in drinking water, wastewater, and the human body. Studies have shown that PFCs pose a threat to human health and the ecological environment, which is expected to be listed in new drinking water regulations. Traditional processes, including coagulation, biological filtration, chlorination, ozonolysis, and ultraviolet light have ineffective removal efficiency on PFCs; however, advanced oxidation processes (AOP) based on ultraviolet (UV) light have good application prospects for the removal of PFCs. This study provides an overview of the removal of PFCs by UV-based AOPs; systematically introduces the research status of various UV-based AOPs from the perspectives of degradation pathways, degradation efficiency, influencing factors, formation of by-products; and comprehensively compares these different UV-based AOPs. Finally, the limitations of existing research and future research needs are discussed. This review aims to provide an overview for a better understanding of the degradation status and prospects of UV-based AOPs for the degradation of PFCs.

This study aimed to evaluate the hydrochemistry of the water resources of the Weibei Plain, Northern China, as well as the risks posed by high groundwater nitrate concentrations to human health. Groundwater and surface water samples numbering 168 and 14, respectively, were collected during the dry and wet seasons. Water in the study area was weakly alkaline, falling into a hard-fresh or hard-brackish category. The groundwater chemical types were mainly SO₄·Cl–Ca·Mg (59.5%) and HCO₃–Ca·Mg (28.6%), whereas the dominant chemistry type of surface water was SO₄·Cl–Na (78.6%). Groundwater showed relatively high concentrations of NO₃⁻, with average dry and wet season concentrations of 212 mg·L⁻¹ and 223 mg·L⁻¹, respectively, whereas surface water had a low NO₃⁻ content. The major processes affecting water chemistry were determined to be rock weathering, such as silicate weathering and evaporative dissolution, as well as cation exchange. NO₃⁻ in groundwater was found to mainly originate from anthropogenic inputs such as agricultural production and domestic sewage. The entropy-weight water quality index (EWQI) assessment showed that although the quality of surface water was generally good, more than half of the groundwater samples failed drinking water standards, with NO₃⁻ identified as being the most problematic parameter affecting the water quality evaluation. Risk assessment of high groundwater nitrate concentrations indicated that long-term domestic use of groundwater in the study area can put the health of residents at great risk. Totals of 81% and 75% of the groundwater samples exceeded the acceptable limit for non-carcinogenic risk (HI = 1) to infants during the dry and wet seasons, respectively, whereas 75% and 71.3% of samples exceeded the acceptable limit for children, respectively. Future management of water in the Weibei Plain should prioritize the control groundwater nitrate pollution.

Molybdenum (Mo) contamination of agricultural soils around Mo-mining areas is of emerging environmental concern. This study evaluated potential practical techniques for chemical immobilization of three Mo contaminated agricultural soils via application of up to six amendments from four different types of materials including biosolids, biochar supported nanoscale zero-valent iron (BC-nZVI), drinking water treatment residues (WTR) and ferrous minerals (magnetite and ferrihydrite). The efficacy of the different amendments on soil Mo bioaccessibility and bioavailability was evaluated by monitoring Mo uptake in both monocotyledon (ryegrass) and dicotyledon (alfalfa) plants, soil extractable Mo, and Mo bioavailability as measured by Diffusive Gradient in Thin Films (DGT®). All amendments exhibited no immobilization effect and increased Mo extractability in the severely contaminated soil (264 mg Mo kg⁻¹). In contrast, in lightly and moderately contaminated soils (22 and 98 mg Mo kg⁻¹), biosolids, WTR and magnetite all reduced soil extractable Mo and decreased Mo uptake in both alfalfa and ryegrass shoots relative to controls (CK). Moreover, DGT showed that during incubation experiments while biosolids amendments increased Mo bioavailability from 115 to 378% compared to the CK treatments, all other amendments decreased Mo bioavailability insignificantly.

Ozone-induced changes in the relationship between photosynthesis (Aₙ) and stomatal conductance (gₛ) vary among species, leading to inconsistent water use efficiency (WUE) responses to elevated ozone (O₃). Thus, few vegetation models can accurately simulate the effects of O₃ on WUE. Here, we conducted an experiment exposing two differently O₃-sensitive species (Cotinus coggygria and Magnolia denudata) to five O₃ concentrations and investigated the impact of O₃ exposure on predicted WUE using a coupled Aₙ-gₛ model. We found that increases in stomatal O₃ uptake caused linear reductions in the maximum rates of Rubisco carboxylation (Vcₘₐₓ) and electron transport (Jₘₐₓ) in both species. In addition, a negative linear correlation between O₃-induced changes in the minimal gₛ of the stomatal model (g₀) derived from the theory of optimal stomatal behavior and light-saturated photosynthesis was found in the O₃-sensitive M. denudata. When the O₃ dose-based responses of Vcₘₐₓ and Jₘₐₓ were included in a coupled Aₙ-gₛ model, simulated Aₙ under elevated O₃ were in good agreement with observations in both species. For M. denudata, incorporating the O₃ response of g₀ into the coupled model further improved the accuracy of the simulated gₛ and WUE. In conclusion, the modified Vcₘₐₓ, Jₘₐₓ and g₀ method presented here provides a foundation for improving the prediction for O₃-induced changes in Aₙ, gₛ and WUE.

Sewage sludge has become a sink of per- and polyfluoroalkyl substances (PFAS) due to the ineffectiveness of PFAS removal during conventional activated sludge treatment process. In this study, we evaluated the performance of an enhanced method for PFAS extraction from sewage sludge. Significant matrix effect was observed for samples derived from untreated and hydrothermally treated sludge. Extra steps for removing potential interferences were thus needed to reduce these matrix effects and improve the accuracy of PFAS quantification. Hydrothermal treatment at 165 °C for 0.5/2 h and 250 °C for 0.5 h increased the concentration of extractable PFAAs in treated sludge. Increasing the temperature to 300 °C resulted in complete degradation of PFCAs after hydrothermal processing, but still increased the concentrations of PFSAs and PFAA precursors. The concentration increase could be due to the conversion of PFAA precursors to PFAAs and the release of PFAAs from sewage sludge during thermal treatment. Ca(OH)₂ addition to hydrothermal treatment completely removed PFAA precursors but significantly increased the extractable PFAAs, except PFHpA and PFHxS, at 165 °C and all PFSAs at 300 °C. This study revealed the difficulties in extracting and quantifying PFAS in sludge and demonstrated the need for further research on finding suitable solutions for complete removal or destruction of PFAS in highly heterogeneous sewage sludge.