High phosphorus (P) load and consequent algal bloom are critical issues because of their harmful effects to aquatic ecosystems. The organic phosphorus (Po) cycling and hydrolyzation pathway in the sediments of a hypereutrophic lake area with high algae biomass were investigated using stable isotopes (δ¹³C and δ¹⁵N) along with C/N ratios, a sequential extraction procedure, ³¹P NMR spectrum, and alkaline phosphatase activity (APA) was measured simultaneously. C/N ratios lower than 10 combined with lighter δ¹³C (−23.5 to −25.2‰) and δ¹⁵N values (3.7–9.5‰) indicated that endogenous algal debris contributed to the predominant proportions of P-containing organic matter in the sediments. Sequential extraction results showed that Po fractions decreased as nonlabile Po > moderately labile Po > biomass-Po. Decreasing humic-associated Po (HA-Po) in sediments downward suggested the degradation of high-molecular-weight Po compounds on the geological time scale to low-molecular-weight Po including fulvic-associated Po (FA-Po), which is an important source of labile Po in the sediment. An analysis of the solution ³¹P NMR spectrum analysis showed that important Po compound groups decreased in the order of orthophosphate monoesters > DNA-Po > phospholipids. The significant correlation indicated that orthophosphate monoesters were the predominant components of HA-Po. Rapid hydrolysis of labile orthophosphate diesters further facilitated the accumulation of orthophosphate monoesters in the sediments. Additionally, the simultaneously upward increasing trend demonstrated that APA accelerated the mineralization of Po into dissolved reactive phosphorus (DRP), which might feed back to eutrophication in algae-dominant lakes. The significantly low half-life time (T₁/₂) for important Po compound groups indicated faster metabolism processes, including hydrolysis and mineralization, in hypereutrophic lakes with high algae biomass. These findings provided improved insights for better understanding of the origin and cycling processes as well as management of Po in hypereutrophic lakes.

Despite growing concern about the occurrence of microplastics in aquatic ecosystems there is only rudimentary understanding of the pathways through which any adverse effects might occur. Here, we assess the effects of polystyrene microplastics (PS-MPs; <70 μm) on a common and widespread algal species, Chlorella sorokiniana. We used laboratory exposure to test the hypothesis that the lipids and fatty acids (FAs) are important molecules in the response reactions of algae to this pollutant. Cultivation with PS-MPs systematically reduced the concentration of essential linoleic acid (ALA, C18:3n-3) in C. sorokiniana, concomitantly increasing oleic acid (C18:1n-9). Among the storage triacylglycerols, palmitoleic and oleic acids increased at the expenses of two essential fatty acids, linoleic (LIN, C18:2n-6) and ALA, while PS-MPs had even more pronounced effects on the fatty acid and hydrocarbon composition of waxes and steryl esters. The FA composition of two major chloroplast galactolipids, monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), were affected implying changes in the conformational structure of photosynthetic complexes in ways that can impair the photosynthesis. These data reveal how exposure to polystyrene microplastics can modify the concentrations of lipid molecules that are important intrinsically in cell membranes, and hence the lipid bilayers that could form an important barrier between algal cellular compartments and plastics in the aquatic environment. Changes in lipid synthesis and fatty acid composition in algae could also have repercussions for food quality, growth and stressor resistance in primary consumers. We advocate further studies of microplastics effects on the lipid composition of primary producers, and of their potential propagation through aquatic food webs.

Mcr-1 and blaNDM₋₁ antibiotic resistance genes (ARGs) confer resistance to colistins and carbapenems, which are often antibiotics used as a last resort in tertiary care hospitals. Dissemination of these two ARGs in drinking water supply systems and their effect on healthy gut bacteria are poorly studied. In this study, the dissemination of mcr-1 and blaNDM₋₁ in a drinking water supply system, and their effect on the antibiotic resistance of mouse gut bacteria are explored.Metagenome analysis revealed that source water (Taipu river and Jinze reservoir) was polluted with ARGs. Mcr-1 and blaNDM₋₁ can be disseminated through the water distribution system. Even advanced water treatments (ozone and biological activated carbon (BAC)) could not effectively remove mcr-1 and blaNDM₋₁. Low concentrations of chloramine disinfectants in the water distribution system were not effective at limiting ARG abundance. Mobile genetic elements were also found to play a major role in the dissemination of ARGs via horizontal gene transfer (HGT) throughout the water supply system. Statistical analysis revealed that there was no effect of temperature on the abundance of mcr-1 and blaNDM₋₁ throughout the water supply system.A last resort ARG, mcr-1 can disseminate from drinking water to the healthy mouse gut. The presence of mcr-1 in a strain belonging to Enterococcus hirae, which is different from the strain belonging to the Bacillus cereus group isolated from drinking water, strongly supports the phenomena of HGT inside the gut.This research provides novel insights into the role of drinking water in disseminating ARGs to the gut and strongly suggests that drinking water may also play a major role apart from other factors known to be involved in the prevalence of last resort ARGs in the gut.

One emerging problem that recently has become a vastly acknowledged topic of concern is the environmental contamination by pharmaceuticals. Diclofenac (DCF) is one of the most common pharmaceuticals found, due to its high utilization and low removal rate in wastewater treatment processes. In this work, Solanum lycopersicum L. was used as a model to unravel how DCF contamination can affect crops, focusing on the internal mechanisms triggered by this exposure. For this purpose, plants were exposed to two different DCF concentrations (0.5 mg L⁻¹ and 5 mg L⁻¹). Results obtained here point towards a loss of shoot performance when plants were exposed to very high concentrations of DCF, but no delay or loss of yield in the flowering and fruit stages were ascribed to DCF contamination. Our data shows that a state of oxidative stress due to high reactive oxygen species accumulation was associated with this contamination, with very high DCF levels leading to a rise of lipid peroxidation, possibly accentuated by the inhibition of ROS-scavenging enzymes and unable to be counteracted by the visible upregulation of proline and the thiol-based redox network. Overall, these results allow to infer that in the current environmental context, no noticeable negative effects should be associated with the presence of DCF in soils where this crop is cultivated. However, the oxidative stress and lower biomass associated with the highest concentration are alarming, since DCF levels in the environment are continuously increasing and further measures are necessary to assess this problematic.

Emerging evidence has showed that exposure to airborne particulate matter (PM) with an aerodynamic diameter less than 2.5 μm (PM₂.₅) is associated with neurodegeneration. Our previous studies in vitro found that PM₂.₅ exposure causes primary neurons damage through activating microglia. However, the molecular mechanism of microglia-mediated neurotoxicity remains to elucidate. In this study, five groups (N = 13 or 10) of six-week-old male C57BL/6 mice were daily exposed to PM₂.₅ (0.1 or 1 mg/kg/day body weight), Chelex-treated PM₂.₅ (1 mg/kg/day body weight), PM₂.₅ (1 mg/kg/day body weight) plus CB-839 (glutaminase inhibitor), or deionized water by intranasal instillation for 28 days, respectively. Compared with the control groups, We found that PM₂.₅ triggered reactive oxygen species (ROS) generation and microglia activation evidenced by significant increase of ionized calcium binding adaptor molecule-1 (IBa-1) staining in the mouse olfactory bulbs (OB). Data from transmission electron microscope (TEM) images and Western blot analysis showed that PM₂.₅ significantly increased extracellular vesicles (EVs) release from OB or murine microglial line BV2 cells, and glutaminase C (GAC) expression and glutamate generation in isolated OB and BV2 cells. However, treatment with N-acetylcysteine (NAC) or CB-839 significantly diminished the number of EVs and the expression of GAC and abolished PM₂.₅-induced neurotoxicity. These findings provide new insights that PM₂.₅ induces oxidative stress and microglia activation through its metal contents and glutaminase-containing EVs in OBs, which may serve as a potential pathway/mechanism of excessive glutamate generation in PM₂.₅-induced neurotoxicity.

The fate of veterinary antibiotics (VAs) in soil environment is determined by the hydrophilic performance and solubility of VAs and the type of soil. In this study, sulfadiazine (SDZ) and chlortetracycline (CTC) were selected as target pollutants, and a batch sorption method was used to find out the single and sorption competitive behavior and mechanism of the target pollutants on loess soil. Kinetic studies showed the apparent sorption equilibrium was reached 0–6 h for CTC and 0–12 h for SDZ. The sorption kinetics of VAs on loess soil were fitted well with a pseudo-second order kinetic model. Sorption thermodynamic data indicated the isotherm sorption of both SDZ and CTC on loess soil was fitted well with Freundlich isothermal (R², 0.960–0.975) and linear models (R², 0.908–0.976). The sorption affinity of CTC (Kd, 290–1620 L/kg for CTC) was much greater than that of SDZ (Kd, 0.6–4.9 L/kg for SDZ). The results also suggest that SDZ may be easily mobilized or leached from loess soil at neutral and alkaline pH, while CTC may be easily mobilized or leached at neutral pH. The sorption of each single target pollutant on the outer layer complex decreased with increasing ionic strength. Higher initial concentrations resulted in greater sorption capacity of target pollutants on loess soil increased. The sorption capacities of CTC and SDZ in the mixed system were lower than the sorption capacity of each single system, showing a competitive sorption behavior of CTC and SDZ during the sorption process. Overall, CTC showed the highest sorption potential in loess soil, whereas SDZ showed a high leaching risk in loess soil. These findings contribute to understanding the fate of different VAs in loess in the natural environment.

Endocrine-disrupting chemicals (EDCs) are compounds that interfere with the expression, synthesis, and activity of hormones in organisms. They are released into the environment from flame retardants and products containing plasticizers. Persistent pesticides, such as dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene, also disrupt the endocrine system through interaction with hormone receptors. Endogenous hormones, such as 17β-estradiol (E2), are released in the urine and feces of farm animals and seep into terrestrial and aquatic ecosystems through sewage. Pigs are widely used as animal models to determine the effects of EDCs because they are physiologically, biochemically, and histologically similar to humans. EDCs primarily disrupt the reproductive and nervous systems of pigs. Moreover, embryonic development during the prenatal and early postnatal periods is particularly sensitive to EDCs. Mycotoxins, such as zearalenone, are food contaminants that alter hormonal activities in pigs. Mycotoxins also alter the innate immune system in pigs, making them vulnerable to diseases. It has been reported that farm animals are exposed to various types of EDCs, which accumulate in tissues, such as those of gonads, livers, and intestines. There is a lack of an integrated understanding of the impact of EDCs on porcine reproduction and development. Thus, this article aims to provide a comprehensive review of literature regarding the effects of EDCs in pigs.

The wide ecological relevance of lipid homeostasis modulators in the environment has been increasingly acknowledged. Tributyltin (TBT), for instance, was shown to cause lipid modulation, not only in mammals, but also in fish, molluscs, arthropods and rotifers. In vertebrates, TBT is known to interact with a nuclear receptor heterodimer module, formed by the retinoid X receptor (RXR) and the peroxisome proliferator-activated receptor (PPAR). These modulate the expression of genes involved in lipid homeostasis. In the present work, we isolated for the first time the complete coding region of the Echinodermata (Paracentrotus lividus) gene orthologues of PPAR and RXR and evaluated the ability of a model lipid homeostasis modulator, TBT, to interfere with the lipid metabolism in this species. Our results demonstrate that TBT alters the gonadal fatty acid composition and gene expression patterns: yielding sex-specific responses in fatty acid levels, including the decrease of eicosapentaenoic acid (C20:5 n-3, EPA) in males, and increase of arachidonic acid (20:4n-6, ARA) in females, and upregulation of long-chain acyl-CoA synthetase (acsl), ppar and rxr. Furthermore, an in vitro test using COS-1 cells as host and chimeric receptors with the ligand binding domain (LBD) of P. lividus PPAR and RXR shows that organotins (TBT and TPT (Triphenyltin)) suppressed activity of the heterodimer PPAR/RXR in a concentration-dependent manner. Together, these results suggest that TBT acts as a lipid homeostasis modulator at environmentally relevant concentrations in Echinodermata and highlight a possible conserved mode of action via the PPAR/RXR heterodimer.

Natural background levels (NBLs) and threshold values (TVs) are crucial parameters for identification and the quantification of groundwater pollution, and the evaluation of pollution control measures. The cumulative probability distribution technique was used for the evaluation of NBLs for 36 samples collected during two climate conditions in the part of the desert area from Rajasthan, India. The NBLs for Na⁺, Cl⁻, SO₄²⁻, HCO₃⁻, NO₃⁻ and F⁻ ions were assessed and compared with the natural and anthropogenic processes. The TVs were also calculated for Na⁺, Cl⁻, SO₄²⁻, HCO₃⁻, NO₃⁻ and F⁻ ions, and compared with the drinking limits of the Bureau of Indian Standards. Additionally, the pollution percentage (%) at the individual well was estimated and identified the polluted zones. Results indicate that most of the polluted areas were situated in the southern part, which was influenced by the natural and anthropogenic factors. The sodium concentrations above the TVs, in indicating the saline nature of water. Chloride threshold value above the drinking water limit was mainly observed in the dry season, related to intensive evaporation and industrial waste, which leads to groundwater quality degradation. The NO₃⁻ concentration (∼56% samples) above the TVs indicates extensive use of nitrate fertilizers and sewage effluent. The values of total dissolved solids (TDS) shows the suspicious scenario as about 84% of the samples in the dry period and about 89% in the wet season exceeding the drinking limit. Assessment of background concentrations and threshold values on regional and local scale assigns the basis for the identification of groundwater pollution, and helpful for better water quality guidelines to protecting of water resources.

Accumulation of potentially toxic elements (PTEs) in agricultural soils has become an increasingly global issue driven by industrialization. A credible knowledge of their distribution and diverse sources in soils is essential to developing effective measures of identifying accumulation of PTEs in rural and periurban environments. However, the assessment of PTE pollution levels and discrimination of anthropogenic and natural sources remain a serious challenge. In China, most studies are focused on highly industrialized and/or urbanized regions, while limited attention has been given to agricultural areas where diffuse source contamination prevails. Therefore, a large dataset of 5207 surface soil samples (1 × 1 km) and 1311 subsoil samples (2 × 2 km) were collected from an agriculturally dominated region in eastern China. Soil total concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn were analyzed along with additional edaphic variables relevant to PTE accumulation in soils (e.g., pH, SOC). Concentrations of Cr, Ni, Pb and Zn for all sites were lower than those of the risk-screening values. However, elevated concentrations of Cd and Hg observed in surface soils were associated with anthropogenic activities. Land use pattern had a significant impact on the spatial variation of PTEs. Elevated levels of Cd were uniquely associated with high phosphorus and soil organic matter (SOM) contents, and elevated Hg was associated with coal-fired power plants and historical application of fertilizer and Hg-containing pesticides. The data presented herein indicated that geogenic process likely caused a net depletion of As, Cr, Cu, Ni, Pb and Zn in topsoil, despite surface deposition from anthropogenic sources. The result of this study revealed that using subsoil concentrations of PTEs to establish background or reference concentrations might lead to an erroneous assessment of pollution levels in surface soils.