Physiological and ecological adaptation mechanisms of tobacco under combined stress of acid rain and cadmium.

Spatiotemporal leaching dynamics and mechanistic insights into heavy metal release from ion-adsorbed rare earth tailings under acid rain conditions

Caring for the environment is a major priority in many countries, as environmental pollution poses a serious threat to natural resources, including water, air, and land. Pollution levels have reached alarming rates, prompting researchers across various scientific disciplines to focus on studies aimed at reducing and controlling these pollutants within permissible limits. Air and atmospheric pollution are among the most dangerous forms of pollution affecting human health and the environment. They contribute to global warming and ozone layer depletion by emitting harmful gases, especially nitrogen dioxide (NO₂). When the concentration of NO₂ in the air reaches 0.07%, it transforms into nitric acid, a lethal gas that can cause death within half an hour. These oxides react with hemoglobin in the blood, hindering oxygen transport to cells, making children particularly vulnerable. Symptoms such as blue lips are common signs of this type of poisoning. In industrial regions like the United States, nitrogen oxides are major contributors to acid rain. With significant advances in digital data recording technologies, environmental data is now captured as a time series. This allows the application of mathematical models to analyze pollutant behavior for control and prediction. In this research, the Particle Swarm Optimization (PSO) algorithm was applied to analyze nitrogen dioxide (NO₂) levels in Baghdad from 2015 to 2017, using weekly averages across 157 observations. The model achieved a prediction accuracy rate of approximately 94%.

The Meteorology, Climatology, and Geophysics Agency (BMKG) publish decennial reports that provide valuable insights into Indonesia's meteorological conditions and their temporal fluctuations. However, due to their narrative structure, conducting direct quantitative analysis is problematic. This study seeks to address this issue by using a transparent, repeatable natural language processing (NLP) method to identify temporal trends in climatic conditions favourable to the formation of acid rain. The collection contains 36 BMKG decadal atmospheric dynamics studies for 2025. The proposed approach entails gathering textual input, performing basic preprocessing (case normalization, character sanitization, space-based tokenization, and stop-word removal), and subsequently employing predefined keyword dictionaries for analysis. These dictionaries delineate weather conditions that either facilitate or inhibit the formation of acid rain. The scores for acid rain conditions are determined by the frequency of specific keywords, adjusted for the document's length. Subsequently, they are categorized into groups utilizing statistical thresholds derived from the mean and standard deviation of the adjusted scores. Non-parametric statistical tests are employed to examine temporal patterns with greater specificity. The findings indicate that normalized acid rain scores are elevated in the initial years of the decade, specifically 2025, before gradually declining until year-end. The Spearman rank correlation test reveals a statistically significant negative correlation between normalized scores and time (\rho = -0.494, p = 0.0022). The Mann–Kendall test indicates a significant downward trend (Z = -2.902). These results demonstrate that the climatic conditions responsible for acid rain occurred only temporarily, rather than year-round. The core element of this work is a straightforward, lexicon-based NLP approach that is easily understood, replicable, and applicable, and can transform narrative atmospheric reports into structured quantitative metrics. This is beneficial for research on atmospheric dynamics and environmental analysis with official written data.

Abstract Acid-hydrolysable nitrogen (AHN), a crucial fraction of bioavailable soil organic nitrogen (N), is highly sensitive to soil acidification. Alkaline biochar (BC) has been shown to effectively mitigate acid rain (AR)-induced soil acidification. However, its regulatory effects and underlying mechanisms on AHN fractions remain largely unexplored. In this study, a field-scale simulated AR experiment was conducted in a Quercus acutissima plantation, utilizing BC derived from Q. acutissima litter to evaluate its impacts on AHN fractions and associated soil chemical-biological drivers. The results showed that after 2 years of simulated AR spraying, BC application elevated soil pH by 0.19 units under AR stress and increased total AHN content by 64.8%. Specifically, acid-ammonia N, acid-amino sugar N, acid-amino acid N, and acid-hydrolyzable unidentified N increased by 45.0%, 61.3%, 80.6%, and 60.7%, respectively. BC-amended soils under AR exhibited the highest bacterial network complexity (0.8), whereas fungal network connectivity was reduced. Soil chemo-biological interactions explained 23.1−39.7% of the variations in AHN fractions. Random forest modeling identified microbial N use efficiency as the primary factor influencing acid-ammonia N, and microbial biomass N as the key factor governing the accumulation of acid-amino acid N and acid-amino sugar N. Furthermore, the regulatory effects of BC on AHN fractions (0.77–0.98) surpassed those of AR stress. This study elucidates the mechanistic pathways through which BC modulates acid-induced N dynamics, providing insights for sustainable N management in plantation ecosystems affected by AR. Graphical Abstract

In the era of the Internet of Things (IoT), droplet-based nanogenerators offer a promising solution for self-powered environmental monitoring. However, conventional displacement-current-driven devices are constrained by fluid-solid interface coupling, which results in low carrier transport efficiency and limits both output performance and sensing sensitivity. To address the need for acid rain monitoring, this study introduces a novel total-current nanogenerator (TCNG) optimized through curvature engineering, enabling an intelligent real-time acid rain sensing platform. By optimizing fluid-solid coupling dynamics and regulating the interfacial electric field gradient, the TCNG enhances spatiotemporal separation and pump accumulation of charge carriers at the solid-liquid interface, thereby improving charge transfer efficiency in the droplet-based nanogenerator platform. The platform exhibits high sensitivity and rapid response for acid rain monitoring, and it incorporates a ResNet18-1D deep learning algorithm to analyze the time-frequency features of the current signals, achieving 99.86% accuracy in identifying the pH values of acid rain. Furthermore, the TCNG delivers a peak voltage of 4500 V, sufficient to power electronic devices. By integrating multiphysics coupling design with artificial intelligence, this work provides a novel strategy for advancing the next-generation IoT-based environmental monitoring platform.

Research on the geochemical characteristics of coal-bearing strata in the Yanqi Coalfield, Xinjiang, remains limited. This study investigates the No. 8- 2 coal seam and its adjacent strata in the Xingmei Mine, which is located in the Yanqi Coalfield, using mineralogical and geochemical methods to characterize its composition, constrain provenance, and clarify the causes of localized barium enrichment. The coal is characterized by low ash and sulfur, high volatile matter, and is dominated by quartz, kaolinite, and pyrite. Trace element analysis reveals that Ba is slightly enriched in the coal samples, whereas it is enriched in the surrounding roof, parting, and floor samples. Provenance analysis suggests detrital input mainly from the central and south Tianshan region. Paleoenvironmental proxies reveal a humid-arid-humid climate shift from roof to coal to floor, with redox transitions from dysoxic to weakly reducing-oxidizing, returning to dysoxic conditions, under freshwater and terrigenous input. Elevated Ba concentrations are observed in samples collected near the coal-roof/floor interfaces, including XM-5P (15,826µg/g) and XM-13 (3,071µg/g), hosted in barite. Barite likely formed under freshwater conditions, high ash content, transitional contact zones, and Ba²⁺ supply from sediment provenance, with SO₄²⁻ most likely derived from acid rain.

ABSTRACT Acid rain-induced dynamic dissolution severely threatens the preservation of near-surface sandstone grottoes and carvings. This study experimentally investigates the temporal evolution of sandstone pore structure, thermal properties, and surface strength under such conditions. Results indicate a two-stage dissolution process: the initial stage shows higher porosity growth and pore volume ratio changes, primarily increasing pore number and size; the later stage significantly alters pore structure and connectivity. With prolonged dissolution, heating/cooling rates decrease, while thermal conductivity and specific heat capacity drop exponentially. Hardness and P-wave velocity also decline exponentially over time. Among the parameters analyzed, porosity exhibits the highest sensitivity to dissolution, followed by hardness and thermal conductivity. Strong correlations exist: hardness decreases linearly with porosity and increases nearly linearly with thermal conductivity, which itself declines exponentially with porosity. These findings enhance understanding of acid rain impacts on sandstone heritage and support the use of thermal infrared detection for assessing surface deterioration.

Aluminum (Al), the third most abundant metal in the Earth's crust, has been preserved for thousands or even millions of years. However, acidic rain and soil acidification, largely driven by human activities related to industrialization and the increased use of Al in daily life, have led to the mobilization of Al from its complex natural resources. This exposure has affected various microorganisms, including bacteria, fungi, protozoa, and yeast, as well as macroorganisms such as plants, animals, and humans, by introducing them to Al in its ionic form. To date, no biological role for Al has been defined in organisms; however, some beneficial effects have been shown, particularly on plant growth. The exposure of living organisms, particularly human cell lines, to chronic and high doses of Al has been the focus of numerous studies. The consequences of such exposure can vary significantly based on the type of organism, their sensitivity, the form of Al, and the dosage used. In plants, these consequences can include inhibited root growth, stunted development, reduced biomass, and disrupted nutrient uptake. In animals, Al exposure can lead to neurological impairments, impaired mineral metabolism, and bone abnormalities. In humans, it may result in encephalopathy, cognitive deficits, microcytic anemia, and an increased risk of Alzheimer's disease. Unicellular organisms, such as yeast and bacteria, may experience decreased cell viability, inhibited growth, and disrupted metabolic processes. This review discusses the genotoxicity of Al in plants, mammals, and yeast cells, as well as the subsequent detrimental effects on cell cycle and cell proliferation. It also explores the underlying mechanisms and pathways associated with these effects. Furthermore, the types of Al-induced cell death as a response mechanism to Al toxicity and the pathways involved in various cell types were discussed.

The application of biochar in soil has demonstrated benefits in reducing greenhouse gas emissions, improving soil properties, enriching soil microbial communities, and effectively adsorbing pollutants to limit their mobility. This study focuses on the adsorption capacity of biochar for pollutants, specifically targeting Cr(VI) and atrazine. The research investigates the ability of biochar to immobilize Cr(VI) and atrazine within soil environments and explores how acidification of biochar can enhance its adsorption capacity for atrazine. The mechanism behind the enhanced adsorption capacity of acid-modified biochar is also examined. The results indicate that applying just 1% biochar can significantly improve the soil system’s capacity to immobilize Cr(VI). Fine-grained biochar shows a markedly higher adsorption and fixation capacity for Cr(VI), exhibiting up to three times the adsorption amount compared to larger biochar particles under certain conditions, with minimal desorption under acid rain leaching. Acidification was found to enhance the adsorption capacity of biochar for atrazine under certain conditions. Both the pre- and post-acidification biochar adsorption isotherms fit the Freundlich model, and adsorption capacity was notably affected by temperature, increasing with rising temperatures. The adsorption kinetics of pre-acid-modified biochar align with the Elovich model, whereas post-acidification biochar follows a pseudo-second-order kinetic model. The enhanced adsorption capacity of acid-modified biochar for atrazine is attributed to an increase in surface area, pore size, and pore volume, providing more adsorption sites and stronger van der Waals forces. Additionally, acidification alters the surface charge of biochar, leading to strong electrostatic attraction between biochar and atrazine.

Long-term leachability and stabilization of lead and cadmium co-contaminated soils using hydroxyapatite-modified drinking water treated sludge.

This study presents a novel synthesis of amino-modified X zeolite (NH2-NaX) derived from low-grade coal gangue via an alkaline fusion-hydrothermal method coupled with a grafting technique. The material was systematically evaluated for its adsorption performance toward lead (Pb) and cadmium (Cd), its efficacy in immobilizing these metals in contaminated soil, and its long-term stability under simulated acid rain leaching. Batch adsorption experiments demonstrated high maximum capacities of 214.123 mg/g for Pb and 256.740 mg/g for Cd. Adsorption kinetics followed a pseudo-second-order model, indicative of a chemisorption-dominated process, while the Freundlich isotherm provided a superior fit over the Langmuir model, suggesting multilayer adsorption involving physiochemical interactions. A 30-day soil incubation revealed that NH2-NaX application significantly increased soil pH from an initial 6.4 to a range of 7.42-8.13 and effectively reduced the bioavailable fractions of Pb and Cd. The amendment promoted the transformation of exchangeable Pb and Cd into more stable residual and reducible fractions, with an optimal dosage identified at 1.5% (w/w). Dynamic leaching experiments under simulated acid rain (pH 5.0) confirmed that NH2-NaX substantially reduced the cumulative release of both metals. Speciation analysis post-leaching showed a marked increase in residual/reducible fractions and a controlled rise in exchangeable metals compared to the untreated control, demonstrating effective inhibition of metal remobilization. These findings collectively establish gangue-based NH2-NaX as a highly efficient, stable, and sustainable amendment for the immobilization of Pb and Cd in multi-metal contaminated soils.

Electrochemical characteristics of anodized equiatomic AlTiNiFeCr high entropy alloy in simulated acid rain solution

Identification of multi-source pollution in peri-urban soil-water systems based on a self-organizing map.

Acid rain threatens plant productivity, including crop yield. The yield of pea (Pisum sativum) is intimately linked to nodulation, nitrogen (N) assimilation, and fixation processes. While the effects of simulated acid rain (SiAR) on crops have been well documented, the specific impacts on N-assimilation remain inadequately understood. This study aimed to investigate the adaptations exhibited by roots and efficiency of N-metabolism in leaves of two widely cultivated Indian pea cultivars (Samridhi and Nandini) in response to varying levels of SiAR (pH 5.6, 5.0, and 4.5). Both cultivars exhibited altered root morphology under SiAR, with increased relative root growth rate at pH 5.0 and 4.5. Increasing SiAR acidity elicited differential responses in N-assimilation enzyme activities across growth stages in both cultivars. SiAR stimulated the activity of nitrate reductase with reduced nitrite reductase and leghemoglobin content in the reproductive growth stage of both cultivars. Under SiAR,both cultivars showed modified seed yield and quality traits;however, cv. Nandini demonstrated greater resilience due to enhanced glutamate dehydrogenase activity, suggesting more efficient N-metabolism than cv. Samridhi. We conclude that the decrease in yield is primarily attributed to the disruption of N-metabolism, specifically inhibition of the glutamine synthetase and glutamate synthase pathway. These findings have significant implications for agricultural practices, in the selection and development of crop varieties with enhanced nitrogen fixation capabilities, to mitigate the negative effects and improve resilience to acid rain.

In 100 Years: An Anthology of Climate Fiction from Nepal’ is a collection of Nepali climate fiction, edited and published by Evan Tims in 2022. The anthology features eight short stories and a poem by eight emerging Nepali writers, envisioning extreme climate change scenarios and their impacts on Nepal a century from now. This study explores these climate narratives through an eco-critical perspective, assessing the plausibility of the climatic situations imagined to occur in Nepal over the next hundred years. For this, it reviews recent news reports from national and international media, government and non-government reports, and relevant journal articles on the issue of climate change and makes a textual analysis of the climate fiction narratives under study. The findings suggest that severe climate hazards projected in the narratives, such as unbearable heat, prolonged droughts, the disappearance of mountain snowcaps, and glacial floods forcing mass migration, are plausible within this timeframe. However, the occurrence of the three districts of Solukhumbu, Sankhuwasabha and Okhaldhunga turning into a gigantic lake, a decade-long drought, and instantly-burning acid rains may not yet be a reality. This study is expected to benefit anyone interested in eco critical readings by deepening their ecological awareness and encouraging thoughtful reflection on the possibility of even more severe effects of climate change in both the near and distant future.

ABSTRACT Municipal solid waste incineration (MSWI) fly ash is a hazardous waste, and traditional landfill disposal lacks sustainability. Resource utilization offers a viable pathway for its future management. Heavy metals are key hazardous components in fly ash, and their stabilization is essential for resource utilization. However, traditional high-temperature treatments are energy-intensive and costly, limiting large-scale application. This study proposed an energy-efficient, medium-temperature treatment method for fly ash and evaluated its environmental risks. Molecular dynamics simulations were conducted to elucidate the underlying mechanisms of heavy metal stabilization. The study revealed that co-sintering fly ash with clay at 750°C and 950°C led to a significant reduction in heavy metal leachability, with Pb and Zn concentrations decreasing by 97.4% and 61.7%, respectively. The sintered products developed new fibrous mineral phases, predominantly wollastonite and rankinite, within which heavy metal ions were incorporated through isomorphic substitution for Ca2+ in the crystal lattice, leading to stable immobilization. Sequential extraction analysis showed that the chemical forms of heavy metals shifted from acid-soluble to more stable reducible and oxidizable fractions after treatment. Consequently, the environmental risk levels of Zn and Pb decreased from moderate to negligible, while that of Cd was reduced from high to negligible. Long-term leaching tests under simulated acid rain conditions confirmed that the sintered products maintain high stability during prolonged environmental exposure.

Transboundary acid rain pollution is a significant environmental issue where sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) emissions from industrial activities, power plants, and vehicles travel across national borders through atmospheric circulation. These pollutants react with water vapor, oxygen, and other chemicals in the atmosphere to form acid rain, which falls to the ground as rain, snow, or fog. Acid rain has severe environmental consequences, including soil degradation, water contamination, forest destruction, and damage to historical monuments. It also poses risks to human health and biodiversity. Many countries have experienced cross-border acid rain disputes, such as the USA-Canada acid rain conflict, which led to the 1991 U.S.-Canada Air Quality Agreement to reduce emissions. Similarly, concerns have been raised about pollution from China affecting India, particularly in the Himalayan region, were black carbon and acid deposition impact glaciers and ecosystems. The issue of transboundary acid rain pollution highlights the need for international cooperation, legal frameworks, and stringent emission controls to address environmental damage and promote sustainable development.

ABSTRACT Over centuries, paper became indispensable across civilizations, yet its modern production presents significant environmental challenges. Today, the pulpwood is among the most resource-intensive sectors. The manufacturing process emits pollutants such as sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and carbon dioxide (CO₂), contributing to acid rain and global warming. Wastewater from paper mills often contains organic matter (like lignin), chlorates, chelating agents, and heavy metals, all of which disrupt aquatic ecosystems by raising biochemical oxygen demand (BOD) and promoting eutrophication. Chlorine-based bleaching further introduces toxic organochlorine compounds into the environment. The industry also contributes to soil degradation through effluent disposal practices. Hazardous substances such as mercury, benzene, methanol, and ammonia present significant health and ecological risks. This study investigates the use of electrocoagulation (EC) as a treatment method for wastewater from a pitchboard industry. EC applies an electric current to remove contaminants via coagulation. Experimental results showed that a charge density of 12 C/L for 20 minutes achieved optimal chemical oxygen demand (COD) removal. COD reduction improved with increasing current density and specific chloride concentrations. Aluminum electrodes performed best at 400 mg/L chloride, while graphite electrodes were most effective at 600 mg/L. Mixed electrode pairs, including graphite – iron and graphite – aluminum, also achieved high removal rates, particularly at 600 mg/L chloride. Additionally, the optimal pH for removal was found to be between 6 and 8.These findings highlight electrocoagulation as a promising, sustainable method for treating wastewater from the pulpwood.

The development of multifunctional artificial synapses capable of integrating molecular sensing and physical stimuli detection remains a challenge due to limited material systems that exhibit both multi-modal responsiveness and tunable synaptic characteristics. Herein, we report two-dimensional perovskite oxide La2Ti2O7 (LTO) nanosheets that are semiconducting and ion conductive, rendering them sensitive to humidity, NO2 gas, and light. A two-terminal device based on the LTO nanosheets exhibited tunable synaptic behaviors and input-dependent switching between excitatory and inhibitory postsynaptic currents. Importantly, a long-term inhibitory memory was achieved, resulting from the light-triggered reaction between environmental H2O and NO2 molecules, which deprived H2O from the LTO surface to bring LTO to a high resistance state. As a proof-of-concept, our two-terminal device was employed for evaluation and early warning of potential acid rain scenarios, demonstrating its advantage of reducing system complexity compared to a conventional system that requires multiple sensors and logic processors. Our work provides a new strategy of using multi-functional sensing materials for artificial synapses in responding to environmental chemical processes.