Nitrogen and phosphorus diffusion at the sediment-water interface is vital to the water quality of lakes. In this paper, N and P diffusive fluxes at the sediment-water interface in Erhai Lake were studied using the sediment-pore water diffusive flux method. Characteristics of temporal and spatial variation of N and P diffusive fluxes were analyzed. Effects of the physicochemical properties of sediments and overlying water were discussed. Results showed that (1) the total N and P diffusive fluxes at the sediment-water interface of Erhai Lake are relatively low. The diffusive flux of ammonia nitrogen is 8.97~74.84 mgd⁻¹ m⁻², higher in the middle of the lake, followed by the northern and southern regions successively. The P diffusive flux is −0.007~0.050 mgd⁻¹ m⁻², higher in northern region of the lake, followed by middle and southern regions successively. The annual N diffusive flux has two peaks, and the higher peak is in September. The annual P diffusive flux shows a “V-shaped” variation, reaching the valley in July. N and P diffusive fluxes decrease with an increase of sediment depth. Overall, N and P diffusive fluxes at the sediment-water interface in Erhai Lake show different temporal and spatial variation. (2) Aquatic plants promote N and P diffusion at the sediment-water interface in Erhai Lake. The pH, DO, and SD of the overlying water are important influencing factors for the P diffusive flux. P diffusive flux is inversely proportional to the total phosphorous (TP) concentration of the overlying water. The physicochemical environment of overlying water slightly influences the N diffusive flux. The activity of sediments and the organic content are two main influencing factors of N diffusive flux, while P content and morphology of sediments are the main influencing factors of P diffusive flux. Iron and manganese ions are important elements that influence N and P diffusive fluxes at the sediment-water interface. (3) The P diffusive flux at the sediment-water interface in Erhai Lake is mainly affected by the physical and chemical properties of water, whereas the N diffusive flux is mainly influenced by the mineralization of organic matter in sediments. The P diffusive flux at the sediment-water interface is sensitive to the overlying water quality. Sediment transformation from “source” to “sink” was observed in 1 year. On the contrary, N diffusive flux is less sensitive to lake water quality. Endogenetic pollutant control in Erhai Lake should focus on P control.

Plants exhibit highly coordinated, dynamic reactions to various abiotic stressors. As cyanide is a non-essential element for plant growth, entry inside plants can exert toxicity at multiple levels. In plant, hormone plays a pivot role under stress conditions. The fluctuations of stress-responsive hormones help in altering cellular dynamics and hence play a central role in coordination and adaptation growth responses under stress. This study focusses on uptake of cyanide in Oryza sativa seedlings and its effect on physiological and on genetic level. Microarray approach has been focused on transcriptional profiling of genes which are involved in systemic acquired resistance for cyanide. Our study shows that the change in different hormonal contents maintained almost the same pattern in roots and shoots upon CN exposure, except for SA. However, the hormone-related gene expression pattern conducted by microarray analysis was inconsistent in both plant materials (root/shoots). Comparison of gene expression between root/shoots showed a total of 29 in roots and 16 DEGs, respectively, indicating that hormone-related genes in roots were more responsive than those in shoots during exogenous CN metabolism. These results showed a remarkable change at transcript level of plant hormone-related genes, including biosynthesis, degradation, induction, and signal transduction under cyanide stress.

In order to solve the separation problem of powdered sludge-based activated carbon (SAC), a series of novel ferromagnetic sludge-based activated carbons (FMSACs, with different iron content 2.3, 4.3, and 9.5 wt%) with a good magnetic separation ability were prepared through co-precipitation method in this study. The structure and physicochemical properties of FMSACs and their catalytic ozonation performance on the removal of p-chlorobenzoic acid (p-CBA) were investigated. The saturation magnetization (Ms) of FMSACs was determined in the range of 0.3674–5.7992 emu g⁻¹, and experiments confirmed that these FMSACs could be easily separated by magnetic fields. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis indicated that magnetite and maghemite were the main magnetic phases in FMSACs. Comparing with ozonation alone and SAC catalytic ozonation, the presence of 2.3 wt% – FMSAC improved the degradation of p-CBA during catalytic ozonation from 44 and 70 to 80%. The tertiary butanol inhibition experiment indicated that FMSACs catalytic ozonation process followed hydroxyl radical reaction mechanism. Furthermore, after six repetitive catalytic ozonation runs, 2.3 wt% – FMSAC still showed relatively high catalytic activity for the removal of p-CBA. Consequently, the novel FMSACs with magnetic separation ability and catalytic performance provide a practical pathway for the sludge utilization.

Compared with other agricultural plants, information about uptake effects of toxic heavy metals from growth soils into persimmon and jujube are scarce. In this study, the single and comprehensive uptake effects of five toxic heavy metals (Pb, As, Cd, Cr, and Hg) between the two fruits and their growth soils were investigated. The results showed that the average concentrations of heavy metals in the two fruits were found to be 30 (Pb), 6.6 (As), 2.3 (Cd), 38 (Cr), and 0.33 (Hg) μg/kg, respectively. The average concentrations of heavy metals in their growth soils were 26.31 (Pb), 9.63 (As), 0.12 (Cd), 57.6 (Cr), and 0.049 (Hg) mg/kg, respectively. An uptake effect was observed for the two fruits. The values of Nemerow pollution index (NPI) in the two fruits and their growth soils were 0.10 and 0.55, respectively. The average bioconcentration factor (BCF) values of Pb, As, Cd, Cr, and Hg in the two fruits were 0.0012, 0.00075, 0.021, 0.00077, and 0.012, respectively. Based on the residue levels of toxic heavy metals in the growth soils and soil parameters, the prediction models for NPI and BCF were established, with the adjusted regression coefficients of 0.65 (NPI) and 0.81 (BCF). The contribution rates of different soil parameters to NPI were 21.7% (OC), 16.1% (Pb), 17.1% (Cr), 19.8% (Cd), and 25.4% (As), respectively. The contribution rates of different soil parameters to BCF were 10.2% (OC), 9.4% (Cr), and 80.4% (Cd), respectively.

The continuous growth and development of population need more fresh water for drinking, irrigation, and domestic in arid countries like Egypt. Evaluation the quality of groundwater is an essential study to ensure its suitability for different purposes. In this study, 812 groundwater samples were taken within the middle area of Upper Egypt (Sohag Governorate) to assess the quality of groundwater for drinking and irrigation purposes. Eleven water parameters were analyzed at each groundwater sample (Na⁺, K⁺, Ca²⁺, Mg²⁺, HCO₃⁻ SO₄²⁻, Fe²⁺, Mn²⁺, Cl⁻, electrical conductivity, and pH) to exploit them in water quality evaluation. A classical statistics were applied for the raw data to examine the distribution of physicochemical parameters in the investigated area. The relationship between groundwater parameters was tested using the correlation coefficient where a strong relationship was found between several water parameters such as Ca²⁺ and Cl⁻. Water quality index (WQI) is a mathematical model used to transform many water parameters into a single indicator value which represents the water quality level. Results of WQI showed that 20% of groundwater samples are excellent, 75% are good for drinking, and 7% are very poor water while only 1% of samples are unsuitable for drinking. To test the suitability of groundwater for irrigation, three indices are used; they are sodium adsorption ration (SAR), sodium percentage (Na%), and permeability index (PI). For irrigation suitability, the study proved that most sampling sites are suitable while less than 3% are unsuitable for irrigation. The spatial distribution of the estimated values of WQI, SAR, Na%, PI, and each groundwater parameter was spatially modeled using GIS.

Chromium pollution is a problem that affects different areas worldwide and, therefore, must be solved. Bioremediation is a promising alternative to treat environmental contamination, but finding bacterial strains able to tolerate and remove different contaminants is a major challenge, since most co-polluted sites contain mixtures of organic and inorganic substances. In the present work, Bacillus sp. SFC 500-1E, isolated from the bacterial consortium SFC 500-1 native to tannery sediments, showed tolerance to various concentrations of different phenolic compounds and heavy metals, such as Cr(VI). This strain was able to efficiently remove Cr(VI), even in the presence of phenol. The detection of the chrA gene suggested that Cr(VI) extrusion could be a mechanism that allowed this strain to tolerate the heavy metal. However, reduction through cytosolic NADH-dependent chromate reductases may be the main mechanism involved in the remediation. The information provided in this study about the mechanisms through which Bacillus sp. SFC 500-1E removes Cr(VI) should be taken into account for the future application of this strain as a possible candidate to remediate contaminated environments.

Over the last decades, engineered nanomaterials have been widely used in various applications due to their interesting properties. Among them, iron oxide nanoparticles (IONPs) are used as theranostic agents for cancer, and also as contrast agents in magnetic resonance imaging. With the increasing production and use of these IONPs, there is an evident raise of IONP exposure and subsequently a higher risk of adverse outcome for humans and the environment. In this work, we aimed to investigate the effects of sub-acute IONP exposure on Wistar rat, particularly (i) on the emotional and learning/memory behavior, (ii) on the hematological and biochemical parameters, (iii) on the neurotransmitter content, and (vi) on the trace element homeostasis. Rats were treated during seven consecutive days by intranasal instillations at a dose of 10 mg/kg body weight. The mean body weight increased significantly in IONP-exposed rats. Moreover, several hematological parameters were normal in treated rats except the platelet count which was increased. The biochemical study revealed that phosphatase alkaline level decreased in IONP-exposed rats, but no changes were observed for the other hepatic enzymes (ALT and AST) levels. The trace element homeostasis was slightly modulated by IONP exposure. Sub-acute intranasal exposure to IONPs increased dopamine and norepinephrine levels in rat brain; however, it did not affect the emotional behavior, the anxiety index, and the learning/memory capacities of rats.

Disinfection of bacteria in water with sustainable and energy-efficient methods is still a great challenge. Herein, a novel gelatin sponge with embedded AgNPs is fabricated via freeze-drying using gelatin as the reducing agent to synthesize AgNPs in situ. UV-vis spectroscopy, HRTEM, XRD, and XPS characterization prove the formation of AgNPs with an average size of 8.55 ± 0.35 nm. TEM and SEM images confirm the even distribution of AgNPs throughout the AgNPs/gelatin sponges. The composite sponge has a low bulk density of 20 ± 3.5 mg/cm³ and a pore size of 6.2 ± 1.5 μm. The AgNPs/gelatin sponges exhibit excellent antibacterial performance to E. coli in water, probably by destroying their cell membranes. The porous AgNPs/gelatin composite sponges are promising filter materials for water disinfection. The removal rate of AgNPs/gelatin composite sponges on E. coli reached almost 100%. Graphical abstract ᅟ

The effects of industrial pollution on bird diversity have been widely studied using traditional diversity measures, which assume all species to be equivalent. We compared species richness and Shannon index with distance-based measures of taxonomic, functional, and phylogenetic diversity (the abundance-weighted mean nearest taxon distances), which describe within-community dissimilarity at terminal branches. Analysis of dissimilarity can shed light on the processes underlying community assembly, i.e., environmental filtering decreases dissimilarity whereas competitive exclusion increases it. In the 2-year study near Karabash and Revda copper smelters in Russia, point counts of nesting birds and habitat descriptions were taken at 10 sites (40 plots) along each pollution gradient. The abundance and diversity of birds showed good repeatability in both regions. The total density of birds, number of species per plot, and Shannon diversity decreased at high toxic load in both regions. The taxonomic, functional, and phylogenetic nearest taxon distances showed the same pattern within regions. Species dissimilarity within communities increased with pollution in Karabash (due to loss of functionally similar species), but did not change in Revda (due to mass replacement of forest species by species of open habitats). Pollution-induced changes in bird communities near Karabash were greater due to the stronger deterioration of the forest ecosystems and less favorable natural conditions (more arid climate, lower diversity and vitality of the tree stand and understorey) compared to Revda. This study emphasizes the need for a multi-level approach to the analysis of bird communities using traditional indices of diversity, functional, taxonomic, or phylogenetic distances between species and environmental variables.

The present study explores the innocuous, biocompatible, and extremely competent molecularly imprinted chitosan/RTIL electrospun nanofibers having average diameter of 30 nm for the expulsion of thorium (IV) ions from the mimicked effluent waste. The extended Flory–Huggins theory and three-dimensional molecular modeling have been effectively premeditated via Materials Studio software for enumerating the inter-miscibility and compatibility (Chi parameter (χ) = 1.019, mixing energy (Eₘᵢₓ) = 0.603 kcal/mol) of the chitosan/RTIL (1-butyl-3-methylimidazolium tetrafluoroborate). The maximum adsorption efficiency is found to be 90% at a neutral pH of 7, and a temperature of 298 K within 120 min. The adsorption process was extensively studied by two-parameter adsorption isotherms like Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich (D–R) and three-parameter models like Redlich–Paterson and Sips isotherm. Pseudo-second-order kinetics model (R² = 0.982) and Langmuir isotherm (R² = 0.994) bestowed the best fitting on chitosan/RTIL nanofibers for the adsorption of Th (IV) ions. The thermodynamic study reveals the spontaneity and exothermic nature of the reaction. The experimental analysis conjoint with isotherm and kinetic models, and simulation study establish the applicability of chitosan/RTIL nanofibers for the expulsion of Th (IV) and other toxic metal ions from the effluents. Graphical abstract Ion-imprinted electrospun nanofiber for expulsion of thorium (IV) ion