Perfluorooctanesulfonic acid (PFOS) is a persistent anthropogenic chemical that can affect the thyroid hormone system in humans and animals. In adults, thyroid hormones (THs) are regulated by the hypothalamic-pituitary-thyroid (HPT) axis, but also by organs such as the liver and potentially the gut microbiota. PFOS and other xenobiotics can therefore disrupt the TH system at various locations and through different mechanisms. To start addressing this, we exposed adult male rats to 3 mg PFOS/kg/day for 7 days and analysed effects on multiple organs and pathways simultaneously by transcriptomics. This included four primary organs involved in TH regulation, namely hypothalamus, pituitary, thyroid, and liver. To investigate a potential role of the gut microbiota in thyroid hormone regulation, two additional groups of animals were dosed with the antibiotic vancomycin (8 mg/kg/day), either with or without PFOS. PFOS exposure decreased thyroxine (T4) and triiodothyronine (T3) without affecting thyroid stimulating hormone (TSH), resembling a state of hypothyroxinemia. PFOS exposure resulted in 50 differentially expressed genes (DEGs) in the hypothalamus, 68 DEGs in the pituitary, 71 DEGs in the thyroid, and 181 DEGs in the liver. A concomitant compromised gut microbiota did not significantly change effects of PFOS exposure. Organ-specific DEGs did not align with TH regulating genes; however, genes associated with vesicle transport and neuronal signaling were affected in the hypothalamus, and phase I and phase II metabolism in the liver. This suggests that a decrease in systemic TH levels may activate the expression of factors altering trafficking, metabolism and excretion of TH. At the transcriptional level, little evidence suggests that the pituitary or thyroid gland is involved in PFOS-induced TH system disruption.

Research on per- and polyfluoroalkyl substances (PFAS) in freshwater ecosystems has focused primarily on legacy compounds and little is still known on the presence of emerging PFAS. Here, we investigated the occurrence of 60 anionic, zwitterionic, and cationic PFAS in a food web of the St. Lawrence River (Quebec, Canada) near a major metropolitan area. Water, sediments, aquatic vegetation, invertebrates, and 14 fish species were targeted for analysis. Levels of perfluorobutanoic acid (PFBA) in river water exceeded those of perfluorooctanoic acid (PFOA) or perfluorooctane sulfonate (PFOS), and a zwitterionic betaine was observed for the first time in the St. Lawrence River. The highest mean PFAS concentrations were observed for the benthopelagic top predator Smallmouth bass (Micropterus dolomieu, Σ₆₀PFAS ∼ 92 ± 34 ng/g wet weight whole-body) and the lowest for aquatic plants (0.52–2.3 ng/g). Up to 33 PFAS were detected in biotic samples, with frequent occurrences of emerging PFAS such as perfluorobutane sulfonamide (FBSA) and perfluoroethyl cyclohexane sulfonate (PFECHS), while targeted ether-PFAS all remained undetected. PFOS and long-chain perfluorocarboxylates (C10–C13 PFCAs) dominated the contamination profiles in biota except for insects where PFBA was predominant. Gammarids, molluscs, and insects also had frequent detections of PFOA and fluorotelomer sulfonates, an important distinction with fish and presumably due to different metabolism. Based on bioaccumulation factors >5000 and trophic magnification factors >1, long-chain (C10–C13) PFCAs, PFOS, perfluorodecane sulfonate, and perfluorooctane sulfonamide qualified as very bioaccumulative and biomagnifying. Newly monitored PFAS such as FBSA and PFECHS were biomagnified but moderately bioaccumulative, while PFOA was biodiluted.

The removal efficiency of antibiotic resistance genes (ARGs) is the biggest challenge for the treatment of erythromycin fermentation residue (EFR). In the current research, 0% (control), 10% (T1), and 30% (T2) spray-dried EFR were composted with bulking materials, consisting of cattle manure and maize straw, for 30 days. Environmental factors and bacterial community on the behaviors of ARGs were further investigated. Apart from the high levels of erythromycin, the electrical conductivities were also increased by 66.7% and 291.7% in the samples of T1 and T2, respectively. After 30 days of composting, total ARGs in the samples of control were decreased by 78.1%–91.2%, but those of T1 and T2 were increased 14.5–16.7- and 38.5–68.7-fold. ARGs related to ribosomal protection (erm) dominated the samples of T1 and T2 at D 13 and 30, especially that ermF accounted for more than 80% of the total ARGs. Furthermore, the results of bacterial community revealed that EFR promoted the growth of Proteobacteria and Bacteroidetes, but inhibited that of Actinobacteria, Verrucomicrobia and Chloroflexi. Network analysis revealed that the enriched ARGs had strong correlation with seven bacterial genera, including Halomonas, Oceanobacillus, and Alcaligenes, most of which are halotolerant. Above all, erythromycin combined with high salinity can have synergistic effect on the enrichment of ARGs and their hosts.

Triclocarban (TCC), a bactericide widely used in personal care products, is frequently detected in soil and surface water, which may affect the environmental behavior of other environmental pollutants by changing the community structure of environmental microorganisms. This work evaluated the effects of TCC on the degradation and migration of seven herbicides and five fungicides in soil under co-occurrence conditions. TCC significantly increased the persistence of the pesticides in soil, and this effect increased with TCC concentration. For example, the half-life of metolachlor, atrazine, metribuzin, and metamitron increased 44%, 38%, 153%, and 33%, respectively, with 10 mg/kg TCC and increased 60%–640% with 100 mg/kg TCC. After 90 days, the residue of the pesticides in soil treated with TCC was significantly elevated relative to the control. TCC treatment could also increase the potential leaching risk of the herbicides in the soil, as indicated by an increased Groundwater Ubiquity Score (GUS) index. The reduced abundance of soil bacteria by TCC might be an essential reason for the impacts on the environmental behavior of the pesticides. This study confirmed that TCC could slow down the degradation of pesticides in soil, increase their persistence and even affect the leaching behavior, thus influencing the risks of the pesticides to the environment.

In recent years, the scale of shrimp ponds has rapidly increased adjacent to mangrove forests. Discharge of shrimp pond effluent has led to degradation of the surrounding environment and reduction of biodiversity in the estuary. But it remains poorly understood how shrimp pond effluent affects functional traits and functional diversity of mangroves. We sampled roots, stems and leaves of Kandelia obovata and other mangrove plants, as well as sediments and pore water from shrimp pond effluent polluted area (P) and clean area (control area, C) in Zhangjiang Estuary in southeast coast of China. Twenty plant functional traits and six functional diversity indices were analyzed to explore the effects of shrimp pond effluent on individual plants and mangrove communities. The results showed that the discharge of shrimp pond effluent significantly affected the nutrient content in soils and pore water, for example, sediment NH₄⁺ and NO₃⁻ concentration increased from 0.26 ± 0.06 to 0.77 ± 0.29 mg/g and from 0.05 ± 0.03 to 0.16 ± 0.05 mg/g, respectively, when comparing the C and P site. Furthermore, some mangrove plant functional traits such as plant height, diameter at breast height, canopy thickness and specific leaf area were significantly increased by the effluent discharge. Functional diversity in the polluted area reduced as a whole compared to the control area. In particular, ammonium and nitrate nitrogen input is the main reason to induce the changes of plant functional traits and functional diversity. Besides, the community structure changed from functional differentiation to functional convergence after shrimp pond effluent discharge. In addition, the long-term shrimp pond effluent discharge may lead to the ecological strategy shift of K. obovata, while different organs may adopt different ways of nutrient uptake and growth strategies in the face of effluent disturbance. In conclusion, pollution from shrimp pond does affect the functional traits of mangrove plants and functional diversity of mangrove community. These results provide strong evidence to assess the impact of effluent discharges on mangrove plants and provide theoretical basis for conservation and sustainable development of mangroves.

In this work, we report a facile receptor OMB [N′,N”’-(3-((4-oxochroman-3-yl)methylene)pentane-2,4- diylidene)bis(4-methoxybenzohydrazide)] for the simultaneous detection of toxic analytes (Hg²⁺ and Cd²⁺ ions) in environment and biological samples. The receptor OMB exhibits an excellent selectivity and sensitivity which was determined using absorption and emission spectra. The receptor OMB shows rapid detection with lowest LOD (0.62 nM for Hg²⁺ ions and 0.77 nM for Cd²⁺ ions) and LOQ (2.08 nM for Hg²⁺ ions and 2.57 nM for Cd²⁺ ions) values. In addition, the receptor OMB exhibits 1:1 binding stoichiometry towards Hg²⁺ and Cd²⁺ ions with binding constant values of 5.5 × 10⁶ M⁻¹ and 4.6 × 10⁶ M⁻¹. Moreover, the synthesized receptor OMB possess ability to detect these analytes (Hg²⁺ and Cd²⁺ ions) in realistic samples (food and water) which was recognized using photoluminescence spectroscopy technique. In addition, the receptor OMB is also utilized to detect both the analytes in live HeLa cells. Thus, the overall results indicate that the receptor OMB was more suitable to detect the toxic analytes (Hg²⁺ and Cd²⁺ ions) present in the environment.

European natural peatlands have undergone long-term anthropogenic drainage activities that have severely decreased their functions, such as carbon sequestration. Recent rewetting has been conducted to restore the ecosystem services of peatlands and mitigate the emissions of potent greenhouse gases such as nitrous oxide (N₂O). However, the magnitudes and spatial patterns of annual N₂O fluxes and their mitigation potentials across European peatlands remain unknown. Here, we synthesized 492 annual N₂O flux data points from 77 in situ studies across European peatlands and found that the soil annual N₂O fluxes varied extensively from −1.08 to 33.40 kg N₂O–N ha⁻¹ yr⁻¹; these results were significantly and interactively (P < 0.05) affected by the peatland status, climatic regime and nutrient supply type. Drainage significantly (P < 0.05) stimulated soil N₂O emissions from natural minerotrophic rather than ombrotrophic peatlands, regardless of the climatic regime. Similarly, rewetting significantly (P < 0.05) reduced soil N₂O emissions from drained minerotrophic rather than ombrotrophic peatlands, demonstrating that the high N₂O emissions were driven by a simultaneous decline in the water table depth and increase in the soil nitrogen (N) availability. Magnitudes of the increases or decreases in N₂O emissions due to drainage or rewetting were also significantly influenced by the land-use and drainage history before rewetting and in the years following drainage/rewetting, respectively. The estimated annual mean N₂O emission total was found to be 90.42 (95% confidence interval: 64.49–122.57) Gg N₂O–N in 2020 from European peatlands. Scenario analysis showed that drained peatlands should be rewetted expeditiously; postponing rewetting would cause larger emissions from continued N₂O emissions from drained peatlands. Fully rewetting the drained peatlands used for forestry and peat extraction and partially rewetting those used for agriculture and grassland comprise a strategy for mitigating drained peatland N₂O emissions without compromising food security.

Antimony (Sb) and arsenic (As) are chemical analogs, but their behaviors in plants are different. To investigate the Sb uptake, translocation and speciation in As-hyperaccumulator P. cretica, a hydroponic experiment was conducted. In this study, P. cretica was exposed to 0.2-strength Hoagland nutrient solution, which contained 0.5 or 5 mg/L antimonite (SbIII) or antimonate (SbV). After 14 d exposure, P. cretica took up 1.4–2.8 times more SbIII than SbV. Since P. cretica was unable to translocate Sb, its roots accumulated >97% Sb with the highest at 7965 mg/kg. In both SbIII and SbV treatments, SbIII was the predominant species in P. cretica, with 90–100% and 46–100% SbIII in the roots. As the first barrier against Sb to enter plant cells, more Sb was accumulated in cell wall than cytosol or organelles. The results suggest that P. cretica may detoxify Sb by reducing SbV to SbIII and immobilizing it in root cell walls. Besides, the presence of SbIII significantly reduced the concentrations of dissolved organic C including organic acids in P. cretica root exudates. Further, increasing Sb levels promoted P accumulation in the plant, especially in the fronds, which may help P. cretica growth. The information from this study shed light on metabolic transformation of Sb in As-hyperaccumulators P. cretica, which helps to better understand Sb uptake and detoxification by plants.

Microplastics (MPs) are an emerging global concern as they are abundant in the environment and can act as vectors of various contaminants. However, whether and how MPs can be vectors of antibiotic resistance genes (ARGs), especially extracellular ARGs (eARGs), remains far from explicit. This study addresses the adsorption of both intracellular ARGs (iARGs) and eARGs by four types of MPs in municipal wastewater, and then explores the potential horizontal gene transfer of iARGs and eARGs exposed to MPs. Results indicate that though MPs significantly adsorbed both iARGs and eARGs, eARGs were adsorbed with a significantly higher fold enrichment (2.0–5.0 log versus 2.0–3.3 log) and rate (0.0056 min⁻¹ versus 0.0037 min⁻¹) than iARGs. While all four types of MPs adsorbed ARGs, polypropylene MPs showed the highest adsorption capacity for ARGs. Background constituents such as humic acid and antibiotics significantly inhibited adsorption of iARGs, but not eARGs on MPs. The presence of sodium chloride didn't significantly affect adsorption of iARGs or eARGs. The adsorption of ARGs was well explained by the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) interaction energy profile. Higher eARG adsorption was attributed to a lower energy barrier between MPs and eARGs than that between MPs and iARGs. Exposure to MPs enhanced horizontal gene transfer of both iARGs and eARGs by 1.5 and 2.0 times, respectively. The improved contact potential between donors and recipients, as well as the increased cell permeability of recipients induced the improved horizontal gene transfer by MPs. This study underscores the need to address ARG propagation through adsorption to MPs.