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Polycyclic aromatic hydrocarbons (PAHs), including acenaphthene, pose a significant threat to aquatic ecosystems by harming vital organisms such as benthic invertebrates. This study evaluated the impact of environmentally relevant concentrations of acenaphthene on Tubifex tubifex, focusing on sublethal acute toxicity and subchronic biomarker responses. Key biomarkers assessed included histopathological changes and the modulation of antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), and malondialdehyde (MDA). Additionally, the study examined structure-activity relationships and species sensitivity distribution (SSD). Concentrations exceeding the solubility threshold of acenaphthene (3.9 mg/L) triggered distinct, concentration-dependent behavioral responses in Tubifex tubifex, such as clumping, mucus secretion, and body wrinkling. Prolonged exposure exacerbated these behavioral dysfunctions, while subchronic exposure resulted in significant histopathological alterations, including epithelial hyperplasia, inflammation, edema, fibrosis, and degenerative changes. The edematic appearance of the body wall suggested a potential immune response to exposure. Furthermore, increased activities of CAT, SOD, and GST indicated oxidative stress in the worms. The study found a 1.5-fold increase in CAT and GST activity, a fivefold increase in SOD, and a striking 100-fold increase in MDA levels compared to controls, signifying an overwhelmed antioxidant defense system and potential cellular disruption. The SSD curve revealed hazard concentrations (HC50 and HC90), indicating that Tubifex tubifex exhibited lower sensitivity to acenaphthene compared to other taxa. In silico analysis and read-across models confirmed the potential of acenaphthene to induce significant oxidative stress upon exposure. The correlation between biomarker responses and structure-activity relationship analysis highlighted the aromatic nature of acenaphthene as a key factor in generating reactive metabolites, inhibiting antioxidant enzymes, and promoting redox cycling, ultimately contributing to adverse outcomes. These findings, coupled with behavioral responses and SSD curve inferences, underscore the importance of the solubility threshold of acenaphthene as a critical benchmark for evaluating its ecological impact in aquatic environments., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study aimed to investigate the toxic effects of benzalkonium chloride (BAC) on Oreochromis mossambicus, a freshwater fish species. Probit analysis was used to determine the lethal concentration (LC 50 ) of BAC for different exposure periods (24, 48, 72, and 96 h). The viability of fish exposed to BAC was assessed using the general threshold survival models (GUTS) and confirmed with relevant datasets to evaluate model accuracy. Experimental groups of fish were exposed to BAC concentrations equivalent to 10% and 20% of the 96-h LC 50 for 45 days. The study revealed significant alterations in various parameters during sublethal BAC exposure. These effects included decreased specific growth rate (SGR), red blood cell count (RBC), hemoglobin (Hb) concentration, hematocrit (Ht) value, plasma protein, and albumin levels, as well as acetylcholinesterase (AChE) activities in both gills and liver. Additionally, an increase in gastrosomatic index (GSI), feed conversion ratio (FCR), plasma glucose and creatinine concentrations, alanine aminotransferase (ALT), aspartate aminotransferase (AST) enzymatic activities, catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) levels were observed in the exposed fish's gills and liver. Furthermore, the study found that glutathione S-transferase (GST) and glutathione peroxidase (GPx) levels initially increased and then decreased in both gills and liver after exposure to BAC. Correlation matrix analysis, multivariate multiple regression (MMR), canonical correspondence analysis (CCA), integrated biomarker response (IBR), and biomarker response index (BRI) were utilized to assess the impact of BAC on fish, highlighting significant effects on multiple biomarkers in O. mossambicus following surfactant exposure. Thus, the study provides valuable insights into the toxic effects of BAC on this fish species, emphasizing the importance of monitoring such pollutants in aquatic environments., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Research for alternative sources for producing renewable energy is rising exponentially, and consequently, microbial fuel cells (MFCs) can be seen as a promising approach for sustainable energy production and wastewater purification. In recent years, MFC is widely utilized for wastewater treatment in which the removal efficiency of heavy metal ranges from 75-95%. They are considered as green and sustainable technology that contributes to environmental safety by reducing the demand for fossil fuels, diminishes carbon emissions, and reverses the trend of global warming. Moreover, significant reduction potential can be seen for other parameters such as total carbon oxygen demand (TCOD), soluble carbon oxygen demand (SCOD), total suspended solids (TSS), and total nitrogen (TN). Furthermore, certain problems like economic aspects, model and design of MFCs, type of electrode material, electrode cost, and concept of electro-microbiology limit the commercialization of MFC technology. As a result, MFC has never been accepted as an appreciable competitor in the area of treating wastewater or renewable energy. Therefore, more efforts are still required to develop a useful model for generating safe, clean, and CO 2 emission-free renewable energy along with wastewater treatment. The purpose of this review is to provide a deep understanding of the working mechanism and design of MFC technology responsible for the removal of different pollutants from wastewater and generate power density. Existing studies related to the implementation of MFC technology in the wastewater treatment process along with the factors affecting its functioning and power outcomes have also been highlighted., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Degradation, detoxification, or removal of the omnipresent polycyclic aromatic hydrocarbons (PAHs) from the ecosphere as well as their prevention from entering into food chain has never appeared simple. In this context, cost-effective, eco-friendly, and sustainable solutions like microbe-mediated strategies have been adopted worldwide. With this connection, measures have been taken by multifarious modes of microbial remedial strategies, i.e., enzymatic degradation, biofilm and biosurfactant production, application of biochar-immobilized microbes, lactic acid bacteria, rhizospheric-phyllospheric-endophytic microorganisms, genetically engineered microorganisms, and bioelectrochemical techniques like microbial fuel cell. In this review, a nine-way directional approach which is based on the microbial resources reported over the last couple of decades has been described. Fungi were found to be the most dominant taxa among the CPAH-degrading microbial community constituting 52.2%, while bacteria, algae, and yeasts occupied 37.4%, 9.1%, and 1.3%, respectively. In addition to these, category-wise CPAH degrading efficiencies of each microbial taxon, consortium-based applications, CPAH degradation-related molecular tools, and factors affecting CPAH degradation are the other important aspects of this review in light of their appropriate selection and application in the PAH-contaminated environment for better human-health management in order to achieve a sustainable ecosystem., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Concerns over adverse environmental effects have been raised due to Vietnam's reliance on fossil fuels like coal. At the same time, efforts are being made to boost the usage of renewable energy while simultaneously lowering greenhouse gas emissions. This study examines whether there is an environmental Kuznets curve (EKC) relationship between gross domestic product (GDP) and coal consumption in Vietnam by controlling for renewable energy consumption and oil prices from 1984 to 2021. We adopt the autoregressive distributed lag (ARDL) framework to explore a long-run level relationship between the study variables. We find that the GDP elasticity of coal demand has been greater than one since the 1990s and about 3.5 in recent years, indicating that the coal intensity of GDP has increased with economic growth. Thus, the GDP-coal consumption relationship resembles an upward-sloping curve instead of an inverted U-shaped EKC. This relationship is robust when we use other estimation methods and account for two additional independent variables. While a 1% rise in renewable energy consumption results in a 0.4% reduction in coal consumption, the impact of oil prices on coal consumption is negative but insignificant. The findings allow us to provide policy implications for the sustainable development of Vietnam: (1) more stringent policies, for example, enacting a carbon pricing scheme, are needed to reduce coal consumption; (2) policies should be implemented to make renewable energy sources more affordable; and (3) as facing high oil prices, the country should diversify its energy mix by expanding the usage of renewable energy., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Lactic and formic acid are two commonly found monocarboxylic organic acids. Lactic acid is discharged into the water bodies as acidic industrial effluent from the food, cosmetic, chemical, and pharmaceutical industries, whereas formic acid is discharged from various paper, leather tanning, and textile processing industries. The present study investigated the toxicity of both organic acids upon the benthic oligochaete worm Tubifex tubifex. The 96-h median lethal concentration (LC 50 ) values for lactic and formic acid are determined as 143.81 mg/l and 57.99 mg/l respectively. The effects of two sublethal concentrations (10% and 30% of 96 h LC 50 ) of these acids on differential expression of oxidative stress enzymes are investigated. The comparative analysis of acute toxicity demonstrates that formic acid exposure is more detrimental to T. tubifex than lactic acid. The in silico structural analysis predicts that formic acid can interact with cytochrome c oxidase of the electron transport system and thereby inhibits its functionality and induces reactive oxygen species production. Integrated biomarker response (IBR) analysis illustrates that overall oxidative stress of formic acid to T. tubifex is significantly higher than that of lactic acid, which supports the structural analysis. It is concluded from this study that toxicokinetic-toxicodynamic and species sensitivity distributions studies are helpful for ecological risk management of environmental toxicants., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Vegetation dynamics is an important aspect for determining climate change trends. The present study delineates to examine spatiotemporal changes of vegetation cover in Pindari valley (Kumaun Himalaya) from the 1972 to 2018 timeline. The study includes the calculation of vegetation spectral indices of normalized vegetation index (NDVI), extraction of different vegetation classes, and statistical analysis of the Mann-Kendall (MK) test on historical metrological data (especially precipitation and temperature) of the study site. For the statistical analysis of metrological data, the power data access viewer datasets have been used. The central feature classes of the study are grassland, scrubland, and forest cover. The results revealed that the region's forest cover significantly decreased by 24.74 sq. km from 1972 to 2018, increased in grassland cover by 17.84 sq. km, respectively, and a slight increase in scrubland class by 3.13 sq. km for the study period. The calculated NDVI shows significant changes over the study location; it has been noticed that the maximum values of the NDVI decreased by 0.24, and the minimum values show growth of about 0.047. The analysis indicates that climatic parameters such as precipitation and temperature are the main limiting factors affecting vegetation growth. The annual mean maximum temperature showed a decreasing trend. The estimated results show an increase in annual rainfall and annual minimum temperature, while the decreasing trend is observed in the case of maximum annual temperature. Objectives of the study are (1) spatiotemporal analysis of the vegetation cover, (2) identification of the main causes of change in the vegetation cover, and (3) statistical trend analysis of long-term metrological data. The outcome of the presented research work would be beneficial for the proper management and monitoring of the forest ecosystem., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

2,4,6-Trichlorophenol (2,4,6-TCP) is a common waste among the resulting chlorophenols generated in the production of common products classified as an extremely toxic, mutagenic, carcinogenic and highly persistent xenobiotic in the environment. To evaluate the impact of 2,4,6-TCP in aquatic systems, the catfish species Clarias batrachus has been selected to test its toxicity due to its high market value and consumption in India. Here is presented the impact of this compound on different physiological parameters of fish: haematological parameters (haemoglobin, total erythrocyte count, total leucocyte count and mean corpuscular haemoglobin), biochemical parameters (total serum protein and total serum glucose), growth and reproductive parameters (condition factor, hepatosomatic index, maturity index, specific growth rate, growth hormone, 17β-estradiol and testosterone), exposed to two concentrations of 2,4,6-TCP (0.5 mg/L and 1 mg/L - 1/10th and 1/20th of the LC 50 ) for a period of 15, 30 and 45 days. The results showed that C. batrachus even when exposed to the lower concentration (0.5 mg/L) for the shortest time (15 days) negatively impacted the organism in all the assessed parameters. This was highlighted by the Integrated Biomarker Response index (IBR), showing worse scores for the treatments (up to 20 × worse than the control). This work highlights the importance of continued research on the impact of 2,4,6-TCP, on an important commercial, supported by the high environmental persistence of this compound that can reach the same range of tested concentrations., (© 2022. The Author(s).)

The present study evaluated the homology modelling, in silico prediction and characterization of Cyprinus carpio cytochrome P450, as well as molecular docking experiments between the modelled protein and the surfactants sodium dodecyl sulphate (SDS), sodium laureth sulphate (SLES) and cetylpyridinium chloride (CPC). Homology modelling of cytochrome P450 was performed using the best fit template structure. The structure was optimized with 3D refine, and the ultimate 3D structure was checked with PROCHEK and ERRATA. ExPASy's ProtParam was likewise used to analyse the modelled protein's physiochemical and stereochemical attributes. To establish the binding pattern of each ligand to the targeted protein and its effect on the overall protein conformation, molecular docking calculations and protein-ligand interactions were performed. Our in silico analysis revealed that hydrophobic interactions with the active site amino acid residues of cytochrome p450 were more prevalent than hydrogen bonds and salt bridges. The in vivo analysis exhibited that exposure of fish to sublethal concentrations (10% and 30% of 96 h LC 50 ) of SDS (0.34 and 1.02 mg/l), CPC (0.002 and 0.006 mg/l) and SLES (0.69 and 2.07 mg/l) at 15d, 30d and 45d adversely affected the oxidative stress and antioxidant enzymes (CAT, SOD, GST, GPx and MDA) in the liver of Cyprinus carpio. As a result, the study suggests that elicited oxidative stress, prompted by the induction of antioxidant enzymes activity, could be attributable to the stable binding of cytochrome P450 with SDS, CPC and SLES which ultimately leads to the evolution of antioxidant enzymes for its neutralization., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The study vigilantly considered the load of Pb, Cd, Cr, Cu, and Zn in a variety of tissues (muscle, gills, and liver) of 5 fish species (Mystus gulio, Notopterus notopterus, Notopterus chitala, Mugil cephalus, and Glossogobius giuris) collected from six sites in the lower Gangetic area. The study showed the lowest concentration of metals in the muscles. The accumulated patterns of heavy metals differed in different regions and concentrations fluctuated between the liver and gills. The target hazard quotient (THQ) value has been measured in contaminated fish. The THQ values for all the metals in respective fishes are below 1 that indicate that indirect intake of metals by consuming these selected fishes will not result in potential health hazard in human. The estimated daily intake (EDI) results were also calculated. EDI levels of all elements are lower than the permissible limit indicating a lower chance for health risk to occur. However, doses below the recommended levels do not indicate that they are completely safe for consumption or those above are not to be used. Thus, it can be demonstrated that occurrence of Cd, Cr, Pb, Cu, and Zn in the preferred tissues of the selected fish species in the present study may not pretense severe human health risk after consumption at its existing concentration., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Cold plasma has been a potent energy-efficient and eco-friendly advanced oxidation technology which has gained attention in recent decades as a non-thermal approach in diverse forms of applications. This review highlights a comprehensive account of the implementation of this technology in the field of wastewater treatment to resolve certain issues regarding the degradation of numerous aqueous pollutants and water-borne pathogenic microorganisms including viruses up to a significant level. The paper addresses plasma chemistry sources and mechanisms on wastewater treatment and impact on various physical, chemical, and biological characteristics of treated water. Furthermore, studies have revealed that this emerging technology is effective in inactivating SARS-CoV-2 or coronavirus, which serves as a transmission channel for this lethal virus in wastewater. Despite these benefits, the development of cold plasma as a wastewater treatment technique is still hampered by a lack of information like capital investment, proficient application, liveability, and operating cost, thus necessitating additional research for its booming commercialization, as this can be an emerging approach to solving water crises and meeting the demand for fresh or potable water resources., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

G20 countries are responsible for more than 80% of global energy consumption and the largest CO 2 emissions in the world. Literature related to the energy consumption-environmental quality-subjective wellbeing nexus is limited and lacks consensus. This paper analyses the impact of energy consumption and environmental quality on subjective wellbeing in G20 countries from 2006 to 2019 using a panel-corrected standard error (PCSE) model. Cantril life ladder data is used as a proxy of subjective wellbeing. For robustness, the Newey-West standard error model is used. The findings reveal that renewable energy consumption and environmental quality, i.e. lesser carbon emissions, enhance subjective wellbeing in G20 countries. In contrast, non-renewable energy consumption degrades subjective wellbeing. Moreover, the study also finds bidirectional causality between renewable energy consumption, non-renewable energy consumption, and economic growth. The policymakers of these countries should encourage renewable energy production and its consumption to reduce carbon emissions for conserving the environment and enhancing their people's subjective wellbeing., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study empirically examines the impact of climate change on cereal production in selected lower-middle-income countries with a balanced panel dataset spanning 1971-2016. The study uses average annual temperature and rainfall to measure climate change. Besides this, CO 2 emissions, cultivated land under cereal production, and rural population are used as the control variables. Second-generation unit root tests, i.e., CIPS and CADF, are used to test the stationarity of the variables. Feasible generalized least square (FGLS) and fully modified ordinary least square (FMOLS) models are used to achieve the objective. Pedroni cointegration test confirms the presence of cointegration between cereal production and climate change variables. The findings show that a rise in the temperature reduces cereal production in lower-middle-income countries. In contrast, rainfall and CO 2 emissions have a positive effect on cereal production. For robustness purpose, the Driscoll-Kraay standard regression and dynamic ordinary least square (DOLS) models have also found similar results. Dumitrescu-Hurlin test has found the bidirectional causality of cereal production with temperature and CO 2 emissions. Also, unidirectional causality is running from rainfall and rural population to cereal production. The adverse effects of temperature on cereal production are likely to pose severe implications for food security. The paper recommends that governments of the sample countries should research and develop heat-resistant varieties of cereal crops to cope with the adverse effects of temperature on cereal production and ensure food security., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A native Indian catfish (Heteropneustes fossilis) and an Indian major carp (Cirrhinus cirrhosus) were treated with sodium dodecyl sulfate (SDS) to elucidate its consequences on antioxidant status and sex steroid synthesis. Fishes were exposed to 1/10th of LC 50 of SDS for 30 days. Different enzymatic and non-enzymatic antioxidants, major sex steroids, steroidogenic enzymes, gonadosomatic index (GSI), and serum cortisol level were measured in both male and female fishes. Levels of enzymatic and non-enzymatic antioxidants altered significantly in both the fish species. Steroid hormones in both male and female fishes decreased significantly in the SDS-treated group. Profiles of steroidogenic enzymes (hydroxysteroid dehydrogenase; 3β-HSD and 17β-HSD) show significant decrease in the SDS treatment group in both carp and catfish than that of the control group irrespective of sexes. GSI also decreases significantly in the SDS-treated group when compared with the control group in spawning phase of carp and catfish irrespective of sexes. Serum cortisol level was increased significantly after SDS exposure. Higher level of cortisol was noted in the spawning phase than that of pre-spawning phase. Current study proves that SDS could interrupt the normal steroidogenesis process in fish, leading to impaired sex hormone production. Detrimental effect of SDS was noted to be more prominent on female steroidogenesis than that of male fish. A species or season-specific variation in steroidogenesis was also observed which indicates that SDS-induced toxicity depends on the sexual status of the specific fish species.

Molluscs have long been regarded as promising bioindicator and biomonitoring subjects for heavy metals as molluscs are highly tolerant to heavy metals and exhibit high accumulation in their body. In spite of several previous studies about the impact of cadmium on molluscs, little information exists in literatures concerning the toxic effects of cadmium on Lymnaea acuminata, especially pertaining to behavioral and hematological changes as these are considered effective bioindicators and biomonitoring variables for detecting heavy metals in polluted water bodies. In the present study, the median lethal concentrations of cadmium chloride to snail, Lymnaea acuminata, were estimated to be 9.66, 7.69, 6.26, and 5.54 mg/L at 24, 48, 72, and 96 h, respectively. For behavioral studies, variable test concentrations of cadmium from 0.00 to 10 mg/L were used. The clumping tendency, crawling activity, and touch reflex in the exposed snails were gradually decreased with higher concentrations at 72 and 96 h. For measuring the hemocyte numbers in the circulating hemolymph of snail during chronic cadmium exposure, two sublethal doses of cadmium (10 and 20% 96-h LC 50 -0.55 and 1.11 mg/L, respectively) were used. A significant variation (p < 0.05) from the control at all exposure times (7, 14, 21, and 28 days) was recorded at 1.11 mg/L concentration. The total count of circulating hemocytes was significantly reduced (p < 0.05) compared to the controls at both concentrations of cadmium exposure at all time periods except 14 and 21 days exposure at 0.55 mg/L where values were non-significantly increased. In comparison between two sublethal doses, blood cells were significantly (p < 0.05) lowered at 1.11 mg/L cadmium treatment. Considering the behavioral and hematological data, it seems possible to forecast the physiological state of snails in cadmium-contaminated water bodies and these findings can be used in determining the safe disposal level of cadmium in aquatic ecosystem.

The present study investigated the comprehensive chemical composition [organic carbon (OC), elemental carbon (EC), water-soluble inorganic ionic components (WSICs), and major & trace elements] of particulate matter (PM 2.5 ) and scrutinized their emission sources for urban region of Delhi. The 135 PM 2.5 samples were collected from January 2013 to December 2014 and analyzed for chemical constituents for source apportionment study. The average concentration of PM 2.5 was recorded as 121.9 ± 93.2 μg m -3 (range 25.1-429.8 μg m -3 ), whereas the total concentration of trace elements (Na, Ca, Mg, Al, S, Cl, K, Cr, Si, Ti, As, Br, Pb, Fe, Zn, and Mn) was accounted for ∼17% of PM 2.5 . Strong seasonal variation was observed in PM 2.5 mass concentration and its chemical composition with maxima during winter and minima during monsoon seasons. The chemical composition of the PM 2.5 was reconstructed using IMPROVE equation, which was observed to be in good agreement with the gravimetric mass. Source apportionment of PM 2.5 was carried out using the following three different receptor models: principal component analysis with absolute principal component scores (PCA/APCS), which identified five major sources; UNMIX which identified four major sources; and positive matrix factorization (PMF), which explored seven major sources. The applied models were able to identify the major sources contributing to the PM 2.5 and re-confirmed that secondary aerosols (SAs), soil/road dust (SD), vehicular emissions (VEs), biomass burning (BB), fossil fuel combustion (FFC), and industrial emission (IE) were dominant contributors to PM 2.5 in Delhi. The influences of local and regional sources were also explored using 5-day backward air mass trajectory analysis, cluster analysis, and potential source contribution function (PSCF). Cluster and PSCF results indicated that local as well as long-transported PM 2.5 from the north-west India and Pakistan were mostly pertinent.

In this study, a natural adsorbent (activated dry flowers (ADF)) was prepared from plant-derived waste biomass by chemical activation and employed for chromium (VI) removal from aqueous medium using experimental batch technique. Experiments were carried out as function of adsorbent dosage, pH, and contact time. The maximum chromium (Vl) removal was observed at initial pH 3 (~94 % removal). The equilibrium data was fitted well to Langmuir isotherm. The adsorption capacity of ADF was found to be 4.40 (mg chromium (Vl)/g) which was comparable to the adsorption capacity of some other adsorbents documented. Among various kinetic models applied, pseudo second-order model was found to explain the kinetics of chromium (VI) adsorption most effectively (R (2) >0.99). Thermodynamic parameters such as ΔG, ΔS, and ΔH shows that adsorption process was spontaneous and endothermic at all the concentration ranges studied. Desorption of chromium (Vl) with 2 N NaOH was effective (~71 %) and, hence, there exists the possibility of recycling the ADF. The major advantages of using ADF as an adsorbent are due to its effectiveness in reducing the concentration of chromium (Vl) to very low levels. It requires little processing and is reversible as well as eco-friendly in contrast to traditional methods.