International Journal of Environmental Research最新文献

Salinity is one of the major factors that limit tomato growth and productivity, causing morphological and physiological changes and impacting plant metabolism. Seaweed extracts can reduce these harmful effects. Therefore, in this study we examined the effect of Cystoseira tamariscifolia extract (CTE) on NaCl stress tolerance in tomato plants. We assessed the effect of different concentrations of CTE on germination parameters of tomato seeds to determine the most effective concentrations. Then, we applied the chosen concentrations (2%, 5%, and 10%) of CTE as soil drench to tomato seedlings (Solanum lycopersicum L.) grown under salinity. Our findings revealed a decrease in the growth of tomato plants exposed to 50 mM of NaCl compared to unstressed ones. However, CTE supplementation, especially at 2%, to the stressed plants increased the plant height by 32.24% compared to stressed control without treatment and elevated biomass and chlorophyll content. Additionally, CTE decreased hydrogen peroxide and malondialdehyde accumulation and increased the activities of antioxidant enzymes: superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST). Moreover, CTE supplementation regulated the alterations in carbon and nitrogen metabolism by increasing the activity of carbon–nitrogen enzymes: phosphoenolpyruvate carboxylase (PEPC), malate dehydrogenase (NAD-MDH), glutamine synthase (GS), glutamate dehydrogenase (GDH), and aspartate aminotransferase (AAT). Furthermore, CTE application increased notably the content of indole acetic acid, soluble sugars, and amino acids and improved the expression of antioxidant metabolites like flavonoids and polyphenols. Overall, our investigations demonstrate that CTE can be used as biostimulant to enhance the salt stress tolerance of tomato plants.

Nowadays, due to the increase in the diversity and extent of environmental pollutants compared to before, the need for high-performance multifunctional semiconductors is felt more than ever to reduce costs and remove several different environmental pollutants at the same time. In the present research, the positive-copper oxide (p-CuO)/negative-zinc titanate (n-ZnTiO₃) as a novel multifunctional heterojunction semiconductor with photocatalytic, electrocatalytic, and antimicrobial capabilities to remove several different environmental pollutants such as rhodamine B (RhB) and methylene blue (MB) organic dyes, 4-chlorophenol antibiotic, and Escherichia coli and Staphylococcus aureus bacteria was synthesized. The crystal phase, morphology and particle size, and particle distribution were analyzed by XRD, FT-IR, Raman, SEM, and EDX/Map analyses. In addition, photocatalytic activity and surface porosity of p-copper oxide/n-zinc titanate semiconductor was analyzed by UV–visible, DRS, and BET devices. The UV–visible analysis indicated a photodegradation yield of 66.67 and 57.14% for rhodamine B (RhB) and methylene blue (MB) dye, respectively, in the presence of light irradiation in optimum experiment conditions of pH:7, temperature: 65 °C, mixing speed: 200 rpm, retention time: 5 h, p-copper oxide/n-zinc titanate value; 1 g/l, dyes value; 10 mg/l and distance between the irradiation source and solution surface: 10 cm. Electrocatalytic activity of p-copper oxide/n-zinc titanate semiconductor for degradation of 4-chlorophenol pollutant with a concentration of 0.0001 M was evaluated by cyclic voltammetry (CV) device in optimal conditions of N-icosane binder percentage: 5%, p-copper oxide/n-zinc titanate modifier value: 20%, pH 7, and scan speed: 300 mv/s. Also, after drawing the cyclic voltametric calibration curve of the 4-chlorophenol pollutant, the target sensor showed a linear behavior with a correlation coefficient of 0.9912. The response range of the sensor was 1.3–1000 μM and the limit of detection (LOD) was 0.93 μM. For the reproducibility of the measurements, the percentage of relative standard deviation (%RSD) was determined, which was measured to be 27.9% at a concentration of 0.75 μM. The increase in the intensity of the 4-chlorophenol oxidation current and the displacement of its oxidation potential in the obtained results indicated the electrocatalytic properties of p-copper oxide/n-zinc titanate semiconductor. Finally, the antimicrobial property of p-CuO/n-ZnTiO₃ semiconductor was investigated at concentrations of 0.15–70 mg/ml on E. coli and S. aureus bacteria. Based on the obtained results, the effective concentration of the desired p-copper oxide/n-zinc titanate semiconductor in inhibiting E. coli and S. aureus bacteria was determined at about 1.09 and 2.18 mg/ml, respectively. Eventually, the p-CuO/n-ZnTiO₃ multifunctional heterojunction semiconductor showed stru

Cadmium (Cd) contamination in rice is a global concern. Manganese (Mn) fertilizer is considered to be a compelling and practical agronomic measure to prevent Cd accumulation in grains. However, high doses of Mn are also toxic, while the effect of different forms of Mn fertilizer on reducing Cd absorption in rice remains unclear. To investigate the effects of low doses (37.5 kg/ha) of different Mn fertilizers (MnCl₂, MnCO₃, MnSO₄, respectively) applied as topdressing fertilizers in combination with alkaline fertilizers on reducing Cd accumulation in rice grown in typical acid Cd-contaminated paddy soil, field experiments were conducted. The findings indicate that the application of MnSO₄ led to a significant increase in soil pH by 0.18–0.27 units and a considerable decrease in CaCl₂-extractable Cd content in the soil, ranging from 37.01 to 31.88%. Moreover, the inclusion of MnSO₄ significantly increased the soil Toxicity Characteristic Leaching Procedure-Extractable Manganese (TCLP-Mn) content by 1.75–1.86 times, thereby promoting the antagonistic interactions between Cd and Mn ions in the rice rhizosphere. Furthermore, it substantially reduced Cd accumulation in rice grains by 6.47–14.00%. Utilizing structural equation modelling (SEM) revealed that soil pH and TCLP-Mn were identified as the major factors inhibiting Cd accumulation in grains, and there exists a direct significant positive effect of soil available Cd on the Cd concentration found within grains. Collectively, the findings suggest that applying low-dose Mn fertilizer, especially MnSO_4, as a topdressing combined with alkaline fertilizers is an economical and promising strategy for remediation of Cd contaminated paddy soil.

Graphical Abstract

Fluoride is an essential element for humans, but its excessive intake can cause harm to health. Adsorption is recommended as one of the most widely applied, affordable and convenient defluorination technologies. In the present study, Mn–Zr–Ethanol (Mn–Zr–Et) composite was prepared by sol–gel method with ethanol used as a solvent and then utilized for the fluoride removal. The removal performance of fluoride by the Mn–Zr–Et adsorbent was investigated through batch experiments. The removal mechanism of fluorine was further studied through analyzing the characteristics of the Mn–Zr–Et adsorbent. Results show that the integration of ethanol with Mn–Zr adsorbent could greatly enhance the removal capacity of fluoride when compared to the Mn–Zr adsorbent, where the adsorption capacity of Mn–Zr–Et adsorbent was 32.87 mg g⁻¹ at the initial fluoride concentration of 50 mg L⁻¹. The Mn–Zr–Et adsorbent had the advantages of fast adsorption rate, wide pH adaptation range and resistance to interference of coexisting anions. To sum up, the Mn–Zr–Et composite is a promising and green adsorbent for the highly efficient removal of fluoride.

Graphical Abstract

Presently, the main reason for global temperature rise is the increased level of carbon dioxide in the atmosphere. This increase is primarily caused by human activities, leading to carbon dioxide (CO₂) emissions that largely contribute to global warming. For better understanding of how rising temperature affects people and for studying the effectiveness of awareness programmes aimed at reducing carbon dioxide in the atmosphere, we have proposed a non-linear mathematical model. The proposed model has been extended further for controlling atmospheric CO₂ emissions as well as reducing costs associated with the execution of awareness programmes by considering variable implementation rate of such programmes over time. The strategy obtained by utilizing the optimal control theory outclasses both constant heuristic and no control strategies. Further, to illustrate the analytical findings, we have performed numerical simulations.

Industrial decarbonisation has become an increasingly important policy issue in recent years, as governments and nations aim to tackle the climate crisis. This study makes use of UK research council and Horizon 2020 data to map the research landscape for industrial decarbonisation. This includes an analysis of 435 projects funded by various UK research councils, and 239 projects funded under Horizon 2020 linked to industrial decarbonisation. This study finds in the UK case, University–Industry–Government links are critical elements of the decarbonisation research landscape. Universities playing key roles in the UK system are often members of the prestigious Russell Group. In the case of the European industrial decarbonisation landscape (as captured by projects funded under Horizon 2020), private firms play a crucial role. This study also maps a country-to-country collaboration network based on industrial decarbonisation research projects funded under Horizon 2020. This study examines the link between country position in the network and share of electricity consumption that comes from coal; no significant relationship is identified.

Once hailed as a ‘wonder material'’ for its low cost, durability, lightweight, flexibility, and water resistance, plastics have now become one of the potent threats to human civilization. Imperatively, light and microbes could play significant roles in plastic degradation. Plastic–semiconductor composites enhance photodegradation, whereas the presence of biodegradable compound in composites may facilitate their degradation by soil microbes. In this work, composite films of polyvinyl chloride (PVC) and zinc oxide semiconductor (ZnO) are synthesized in various combinations and subjected to sequential photo- and biodegradation. The photodegradation was exclusively solar, whereas polycaprolactone (PCL) was apprehensively added to the composite for enhancing the biodegradability. The process sequence was also altered to investigate the possible effects. Sequential photocatalytic degradation under sunlight and biodegradation by bacteria isolated from soil could decrease the original weight of a photo-bio degradable polymer composite film comprising of PVC, PCL and ZnO in less than a month. The isolated microbe was later identified as Bacillus altitudinis by 16S rRNA gene sequencing. Identification and isolation of enzymes involved in PVC degradation by the isolated strain may be included in future work. Maximum 26.8 w% degradation was observed within 25 days in case of PVC–ZnO composite. The role of PCL was found to be insignificant in biodegradation especially in presence of ZnO. The solar photodegradation was modelled based on a proposed mechanism that finally led to two parallel reaction pathways following first- and zero-order kinetics, respectively. Biodegradation, on the other hand, was noted to be fairly consistent with the Michaelis–Menten kinetics.

The biomineralization process is a relatively modern ground improvement technique wherein microbial activity is increased to improve soil stiffness. Bacteria and enzymes are used to carry out the ureolysis process which leads to the formation of calcium carbonate that binds the soil particles. Biopolymers are also used to improve the engineering properties of soil. This study aims to present a detailed insight into the efficacy of various methods with respect to the type of bio-agent, soil, optimal concentration, and solution injection scheme. The effect of the biomineralization techniques on soil engineering properties such as unconfined compressive strength, shear strength, and permeability is discussed. The cost-effectiveness is studied to help identify the total optimum production cost of different methods in accordance with the raw materials cost. The concept has been found to be especially useful in the mitigation of liquefaction hazards and the prevention of soil erosion. The existing literature primarily discusses the increase in the strength of soil post-process. The potential field applicability, related challenges, and problems are also presented in this review. The major challenge in adopting the technology at field is the cost of the treatment and the problem is obtaining uniform bio-mineralization across the depth of treatment. The cost-related issue can be handled using industrial by-products for the growth of bacteria, while engineering aspects of bio-mineralization have to be understood to make it field applicable.

The leaching of contaminants is a complex, pivotal process for understanding how biochar can immobilize them effectively. In this study, we investigated the impact of biochar, produced at different temperatures, on the behavior of arsenic (As) and lead (Pb) in leached sediments. Before leaching, we combined biochar with sediment, allowing it to naturally age for 365 days. The biochar derived from sugarcane straw was pyrolyzed at 350 °C (BC350), 550 °C (BC550), and 750 °C (BC750). Using UV–Vis spectroscopy, we assessed changes in dissolved organic carbon quality and examined geochemical alterations employing high-performance liquid chromatography–inductively coupled plasma mass spectrometry (HPLC–ICP-MS). The addition of biochar decreased Pb mobility while increasing As mobility. The extent of immobilization varied depending on the pyrolysis temperature: BC750 notably reduced Pb leaching by 54%, whereas BC350 enhanced As mobility by 2.5 times. Although no leaching of monomethylarsonic or dimethylarsinic acids occurred, both BC350 and BC750 amplified As³⁺ leaching by 2.5 times. In summary, biochar addition at different temperatures altered the environmental fate of As and Pb. Higher pyrolysis temperatures, as seen with BC750, were more effective in mitigating Pb mobility, reducing sediment leaching by 54%. Interestingly, exogenous dissolved organic carbon and phosphorus promoted As leaching.