Water Reservoir Research Articles

Estimating Water Depth of Different Waterbodies Using Deep Learning Super Resolution from HJ-2 Satellite Hyperspectral Images

Hyperspectral remote sensing images offer a unique opportunity to quickly monitor water depth, but how to utilize the enriched spectral information and improve its spatial resolution remains a challenge. We proposed a water depth estimation framework to improve spatial resolution using deep learning and four inversion methods and verified the effectiveness of different super resolution and inversion methods in three waterbodies based on HJ-2 hyperspectral images. Results indicated that it was feasible to use HJ-2 hyperspectral images with a higher spatial resolution via super resolution methods to estimate water depth. Deep learning improves the spatial resolution of hyperspectral images from 48 m to 24 m and shows less information loss with peak signal-to-noise ratio (PSNR), structural similarity (SSIM), and spectral angle mapper (SAM) values of approximately 37, 0.92, and 2.42, respectively. Among four inversion methods, the multilayer perceptron demonstrates superior performance for the water reservoir, achieving the mean absolute error (MAE) and the mean absolute percentage error (MAPE) of 1.292 m and 22.188%, respectively. For two rivers, the random forest model proves to be the best model, with an MAE of 0.750 m and an MAPE of 10.806%. The proposed method can be used for water depth estimation of different water bodies and can improve the spatial resolution of water depth mapping, providing refined technical support for water environment management and protection.

Effects of Storm Runoff on Bacterial Community Structure and Metabolic Activity and Water Quality in a Drinking Water Reservoir

To explore the influence of storm runoff on bacterial metabolic activity and water quality in Jinpen Reservoir, three-dimensional fluorescence spectroscopy parallel factor analysis, high-throughput DNA sequencing technology, and Biolog technology were used to analyze variations in the components of dissolved organic matter, bacterial community composition, and microbial metabolic activity during three periods （before, during, and one month after runoff）. The results showed that after storm runoff into the reservoir, the water temperature decreased, and dissolved oxygen in the middle of the water column increased significantly. Finally, the aerobic and low-temperature state in the middle water and anaerobic and low-temperature state in the bottom water was formed. Simultaneously, the concentration of total nitrogen, total phosphorus, organic matter, and turbidity increased significantly. After one month of runoff, the concentration of pollutant decreased, however, was still higher than that before runoff. Further, during the runoff period, the proportion of Proteobacteria and Bacteroidetes increased significantly and the sum of their relative abundance accounted for 63.6% of the bacterial community. The bacterial metabolic activity was also higher than that before. One month after runoff, the bacterial population structure did not recover and the bacterial metabolic activity still remained at a high level.

STUDY ON THE EFFECT OF METALS CONCENTRATION ON BIOCHEMICAL PARAMETERS IN OREOCHROMIS NILOTICUS OF WARWADE RESERVOIR, DUTSE, JIGAWA STATE-NIGERIA

Warwade water Reservoir and Oreochromis niloticus’s tissues (gills and liver) were evaluated by analyzing heavy metals concentrations and their effects on the oxidative stress enzyme from January to August 2022. Both field and laboratory assessments were conducted following established scientific protocols. Monthly sampling occurred between 6:00 – 7:00 am. Four stations denoted as A, B, C, and D, were chosen based on the diversity of anthropogenic activities surrounding the reservoir. The findings showed that heavy metals concentrations in the water ranked as follows: Chromium at 1.96mg/L, followed by Lead (1.74mg/L), Nickel (1.36mg/L), and Cadmium (1.03mg/L). Heavy metals values in fish tissues exhibited a significant decrease (p<0.05) in the following order for gill tissues (Pb > Cr > Ni > Cd) and liver (Pb > Cr > Cd > Ni). The recorded vlaues exceeded the recommended limits set by WHO (2021). Enzyme activities serving as oxidative stress biomarkers demonstrated a significant reduction (P<0.05) for Superoxide dismutase (SOD), Catalase (CAT) and Glutathione Transferase (GST), with higher mean activity observed in the gills with SOD (16.57 ±0.43), CAT (23.61±2.11) and GST (84.40±1.03) compared to liver samples of GST (81.10±0.51), SOD (14.32 ±1.08) and CAT (20.51±0.17) respectively. It may be inferred that the presence of metals in Oreochromis niloticus is a consequence of the discharge of pollutants into the water body, attributable to urbanization and the discharge of agrochemicals, which adversely impacted the water quality. Consequently, it is imperative to regulate uncontrolled discharges from human activities within the reservoir to mitigate the long-term degradation...

Study of monitoring of water bodies using remote sensing data and GIS technologies (Talimarjan water reservoir)

Abstract The study of water bodies using remote sensing data and Geographic Information System (GIS) technologies is crucial for effective water resource management. This research focuses on monitoring the Talimarjan water reservoir, a vital water source in Uzbekistan, by leveraging satellite imagery and GIS tools. Remote sensing offers a cost-effective and comprehensive approach to assess various parameters, including surface area, water quality, and seasonal fluctuations in water levels. By utilizing multi-temporal satellite data, changes in the reservoir’s volume and surrounding vegetation were analyzed. The integration of GIS technologies facilitated the mapping and spatial analysis of these changes, enabling the identification of trends and potential risks, such as sedimentation and water loss. The combination of remote sensing and GIS provides valuable insights into the health and sustainability of the water reservoir, aiding in decision-making for water management authorities. This study demonstrates the effectiveness of these technologies in environmental monitoring, highlighting their potential for broader applications in the management of water resources in arid regions. Through accurate, real-time data, remote sensing and GIS help in ensuring sustainable water use, promoting efficient resource management, and mitigating the impacts of climate change on water bodies.

Deciphering the antibiotic resistome in stratified source water reservoirs in China: Distribution, risk, and ecological drive

Deciphering the antibiotic resistome in stratified source water reservoirs in China: Distribution, risk, and ecological drive

Multiple hydrothermal events at martian surface revealed by H and Cl isotope systematics of melt inclusions and hydrous minerals from chassignite NWA 2737

The chassignites and nakhlites could have co-magmatic origin but display distinct hydrogen and chlorine isotopic compositions, indicating that they may have experienced distinct hydrothermal activities on Mars. However, the details are not yet fully understood. Here, we performed H and Cl isotopic investigations on hydrous minerals (kaersutite and apatite) and glass-bearing melt inclusions from chassignite NWA 2737 to unravel the details of the hydrothermal events experienced by chassignites on Mars. Our results demonstrate that at least two hydrothermal events on Mars have been recorded in NWA 2737. A D- and 37Cl-rich martian crustal/underground fluid was added to the parent magma of NWA 2737 prior to the entrapment of melt inclusions and later interaction of the parent rock with a D-poor fluid, probably deriving from magma degassing. The notable high-δD values (up to 6239‰) of kaersutite in NWA 2737 are comparable with those recorded in younger shergottites, suggesting that the martian exchangeable water reservoir has retained a nearly constant δD value over the past 1.3 Ga.

Synthesis and functional properties of reduced graphene oxide/bismuth-doped gadolinium ferrite composites

An upsurge in water pollution with developing age leads scientists to exploit new materials and technologies for water purification. Herein, we used a co-precipitation approach to prepare rGO/BixGd1-xFeO3 composites to tackle waste organic dyes in fresh water reservoirs. Bismuth at different concentrations is used to tailor the functionality of gadolinium ferrites deposited on reduced graphene oxide. X-ray diffraction pattern describes the unit cell structure of the composite to be distorted orthorhombic with crystallite sizes in the range of 20-15 nm which are confirmed by scanning electron microscopy. Band gaps are calculated by Tauc plots and are in the range 2.62-2.38 eV and 0.9945-0.2873 eV for direct and indirect calculations making these composites suitable photocatalysts. Textural analysis of the samples is carried by Brunauer-Emmett-Teller surface measurements and the surface area is found to be in the range 62.1 to 29.9 m2g−1. Dielectric studies prove that rGO/Bi0.05Gd0.95FeO3, with the highest dielectric constant and capacitance, is better semiconductor among all six synthesized composites. This result is further supported by impedance analysis. In the presence of ultraviolet-visible light, rGO/Bi0.05Gd0.95FeO3 shows 97.2% degradation of methylene blue dye, a common industrial pollutant, with rate constant 0.006 min−1 while rGO/GdFeO3 only degraded 72.6% of MB. The enhanced photocatalytic ability of rGO/Bi0.05Gd0.95FeO3 is evident through low band gap, small crystallite size, less electron-hole recombination in photoluminescence, large surface area and linear I-V response.

Effects of Operations of Various Water Reservoirs and Dams According to their Safety for the Surroundings Areas

Dams are essential pieces of infrastructure that are required for river navigation, flood risk reduction, agriculture, water security, and the production of clean energy. However, controlling dam operations becomes more complex as a result of these several, frequently incompatible goals. Furthermore, dam infrastructure has been developing into intricate system-ofsystems with several interdependent parts and subsystems that are all vulnerable to a variety of uncertainties. Due to these intricacies and uncertainties, numerous research projects centered on dam systems and reservoir operational safety have been initiated. This work focuses on the latter by doing research-on-research, or meta-research, on previously published studies in order to pinpoint important research gaps and suggest future lines of inquiry. In order to discover and categorize significant and latent issues in the discipline, this research first conducts a quantitative analysis of the relevant literature using text mining and then topic modeling. The highlighted subjects are then critically reviewed using qualitative analysis, which explores the concepts, definitions, modeling methods, and key research trends. The study specifically targeted seven topics: water supply management, flood risk, inflow forecasting, hydropower generation, climate change, optimization models, and risk-based assessment and management. The paper also identifies three primary research needs related to the lack of resilience-guided management of dam operational safety, modeling tool capabilities, and modeling idea constraints. In order to guarantee the resilience of such vital infrastructure, particularly in the era of climate change, this study provides an overview of the existing research on dam and reservoir operational safety, the knowledge gaps related to it, and possible future research avenues.

Genesis of artesian waters

Mankind has entered the era of fresh water scarcity. And the questions of the origin of these waters, as well as the methods of effective search for underground fresh water, become fundamental for the assessment of the prospects of water supply of the Earth's population not only in theoretical, but also in applied values. The article considers the volcanic-marine paradigm of artesian water genesis, which allows a logical explanation of a number of deep freshwater phenomena that cannot be resolved by other theories. The main consequences of the volcanic-marine paradigm are: (a) artesian water is recoverable, (b) deep freshwater resources are included in the water cycle in nature like groundwater, (c) the problem of extracting potable artesian water is not a resource problem for mankind, but a technological problem. At present, artesian water is searched for by drilling wells (direct method) and by geophysical methods of groundwater exploration—electrical survey, seismic survey and magnetic resonance method. At the same time, the great depth of artesian water, up to 1000 m, makes it difficult to locate it using geophysical methods. The article considers the geophysical method of direct detection of artesian water in various geological structures at great depths. This method and the service based on it have been named “Geodirect RSS/NMR”. Their physical basis is the resonance between the pre-recorded spectrum of the sought substance (in our case, artesian water) and the spectrum of radiations recorded by the satellite instrumentation in the infrared range. The presence of resonance allows direct identification of artesian water flows and reservoirs without interpretation of indirect data.

Methane degassing in global river reservoirs and its impacts on carbon budgets and sustainable water management

Degassing methane (CH4) through reservoir water compromises hydroelectricity's presumed low-carbon status, which has emerged as a critical hotspot for global carbon dynamics. However, a comprehensive understanding of the involved pathways remains elusive, hindering the accurate estimation of global reservoirs' carbon budget (emission-to-burial ratio). This study presents a holistic upscaling approach to assess methane degassing in global river reservoirs and its impacts on carbon budgets. Firstly, a machine learning model is utilized to characterize the contributions of climate and human factors to annual water residence time. Secondly, the stepwise multiple linear regression method is used to calculate CH4 degassing emissions for each reservoir. Finally, to systematically tackle all sources of uncertainty, separate uncertainty analyses are implemented for the estimates of degassing emissions, areal emissions, and organic carbon burial. Analyzing 30-year data from 6695 reservoirs worldwide, our assessment considers water residence time, temperature, catchment area, and reservoir size. Findings indicate that water releases contribute significantly to global CO2 emissions from reservoirs, elevating the carbon budget by 20 % from 2.02 to 2.18 TgC/year, underscoring the previously underestimated significance of CH4 degassing in shaping the carbon cycle impact of river reservoirs. We propose a redefined threshold for low carbon credits, suggesting that reservoirs with power densities exceeding 6.1 MW/km2, instead of the conventional 4 MW/km2, should qualify. This study underscores the need for sustainable water management and reshaping the carbon dynamics associated with hydroelectricity. Future research can advocate Artificial Intelligence (AI) techniques to enhance water management and mitigate carbon emissions by multi-objectively optimizing reservoir operations.

Capillary rise in a packing of glass spheres

A series of experiments are performed to give insight into the mechanisms of liquid rise in a 3D dense random packing of glass spheres. A sharp knee in the log-log plot of water height h versus time t curve is observed, with an attendant change in h(t) characteristic from h∝t0.5 to h∝t0.05. This behaviour is observed for 5 choices of diameter distribution of spheres, such that the mean diameter is in the range of 0.22 mm to 1.20 mm, and the ratio of standard deviation to mean diameter lies between 0.014 and 0.157. Immediate arrest in water rise occurs when the water reservoir is removed from the bottom of the column, in support of the conclusion that water rise is by capillary action. In the post-knee regime of the h(t) response, water rise occurs in a jerky manner by a series of jumps, involving transverse jumps and more occasional vertical jumps in water ingress; each jump is by an increment of sphere diameter. The incubation time for each vertical jump is sensitive to height of meniscus and dictates the overall rate of water rise. Pendular-rings at the junctions between glass spheres are not observed above the meniscus; this casts doubt upon the notion that the jerky motion of the meniscus is due to the incubation time for a vapour-fed pendular-ring to grow and coalesce with the meniscus. Possible sources of the height-dependent incubation time for each vertical jump are discussed, including a time-dependent increase in surface tension. Additional insight is obtained by observing water rise, and glycerol rise in (i) a monolayer of glass spheres, (ii) in a capillary tube of diameter slightly greater than that of the glass beads and filled with a single column of glass spheres and (iii) an empty capillary tube. Continued liquid rise beyond the knee in the h(t) curve is noted in all cases except for that of an empty capillary tube.

Causes and Evolution of High Injection–Production Ratios in Low-Permeability Reservoirs: The Role of Water Absorption in Barrier and Intercalated Layers

During the waterflood development of low-permeability reservoirs, the lithology of barrier and intercalated layers adjacent to the reservoir, with specific permeability and porosity, has a significant impact on water injection efficiency and reservoir energy recovery. However, current research on injection–production parameters and pressure changes in low-permeability reservoirs has not fully considered the effect of these barrier layers. Therefore, this study focuses on the Chaoyanggou Oilfield, a typical low-permeability reservoir, aiming to reveal the influence of water absorption by barrier layers on water injection efficiency and pressure changes in the reservoir. The study systematically analyzes the evolution of the injection–production ratio at different development stages by constructing a comprehensive lithological geological model and applying numerical simulation methods. It explores how the water absorption characteristics of barrier layers affect reservoir pressure and injection efficiency. The results demonstrate that argillaceous siltstone and silty mudstone have significant water absorption effects on injected water, critically influencing pressure distribution and fluid flow dynamics in the reservoir. As the water cut increases, the injection–production ratio gradually stabilizes, and the elastic water storage in the reservoir becomes crucial for establishing an effective oil displacement system. The water absorption of barrier layers accounts for 30% to 40% of the injected water. A high injection–production ratio alone does not lead to rapid energy recovery or increased production. Only by balancing the injection–production ratio, reservoir pressure, and water absorption in barrier layers can the efficiency and recovery rate of waterflood development in low-permeability reservoirs be further improved.

Performance Analysis of Secondary Side of HPR-1000 Nuclear Power Plant

The trend of advanced nuclear power plant is regaining confidence around the globe because of their clean, relatively safe and reliable energy generation. As per World Nuclear Association, it covers around 10 % of world’s total electricity demand. From engineering perspective, operating these power stations close to their optimum efficiencies is of paramount importance. However, this objective is compromised due to several reasons, such as irreversibility, fouling and seasonal variation in cold water reservoir temperatures. One of the successful way to investigate these problems is through energy and exergy analysis. The aim of this study is to perform the thermodynamic analysis on an advanced HPR-1000 (Pressurized Water Reactor) nuclear power plant using Engineering Equation Solver (EES). The computational model is developed and validated based on the vendor provided design data. The thermal analysis has been carried out at normal power condition to evaluate the energy and exergy losses in major plant components. It further explains the impact of sea water temperature and fouling resistances variation on various performance parameters of plant and condenser. The results indicates that 70 % exergy destruction is calculated at the nuclear island side succeeded by steam generator and condenser. While the major energy loss of 1924 MW is estimated in the condenser at design conditions. The thermal efficiency reduced by 1.75 % while increase of 5.18 % in 2nd law efficiency is observed for varying sea water temperature from 5 to 35 °C. Condenser pressure, overall heat transfer coefficient and condenser exergetic efficiency are observed to exhibit a direct relation with cooling medium temperature. Conversely, these parameters decline with increment in fouling.

A Stable Isotope Analysis to Quantify the Contribution of Basal Dietary Sources to Food Webs of Drinking Water Reservoirs

This study investigates the food web structure of the Xinlicheng Reservoir, a drinking water source of critical importance in Changchun, China, by employing stable isotope analysis (SIA) to quantify the contribution ratios of four basal dietary sources—phytoplankton, zooplankton, sediment organic matter, and particulate organic matter (POM)—to the diets of two key filter-feeding fish species, Hypophthalm ichthys molitrix and Aristichthys nobilis. The analysis reveals that phytoplankton is the dominant dietary source for both species, contributing 32.08% and 34.06%, respectively, whereas the POM contribution is discernably lower (13.25%). The average trophic level of the fish assemblage in Xinlicheng Reservoir is 3.03, while the trophic levels of the two filter-feeding species lie between 3.00 and 3.50. Furthermore, a random forest model was used to identify key environmental drivers of isotopic variations in these basal dietary sources, highlighting the significant role of pH, total nitrogen (TN), chloride (Cl−), calcium (Ca2+), phosphorus (TP), and silicate (SiO44−) in influencing carbon and nitrogen isotopic ratios. These findings provide critical insights to optimize biomanipulation strategies aimed at improving water quality in drinking water reservoirs by enhancing our understanding of the environmental factors that govern trophic interactions and broader food web dynamics.

Sustainable Solutions to Safety Risks on Frozen Lakes Through Effective Risk Mitigation Using Crisis Management Logistics

This article addresses the critical safety risks posed by the use of frozen lakes, risks which are increasingly exacerbated by the impacts of climate change. In Slovakia, where numerous water reservoirs are legally designated for year-round recreational and sporting activities, safeguarding public health and safety necessitates innovative and sustainable approaches to risk mitigation in emergency management. Using the Jazero water reservoir as a case study, this paper demonstrates that the integration of comprehensive risk assessment, the strategic selection of rescue methods, and the deployment of advanced technical equipment for rescue teams are fundamental to ensuring a robust and efficient crisis management response. Through a comparative analysis of nine access routes, validated by tactical exercises and a detailed evaluation of three distinct rescue methods combined with different equipment types, this study reveals the critical role of optimized rescue strategies in reducing response times. Rescue operations were accelerated by at least 4.5 s, a significant reduction that could be the deciding factor between life and death in real-world scenarios. The proposed sustainable strategies for the Jazero reservoir are applicable to similar natural water bodies, underscoring the vital importance of proactive, data-driven, and adaptive crisis management systems in enhancing both immediate and long-term public safety.

Response of dissolved organic matter and disinfection by-product precursors to algal blooms and thermal stratification in deep reservoirs.

Algal bloom contribute substantially to dissolved organic matter (DOM) and disinfection by-product (DBP) precursors in deep reservoirs, threatening drinking water safety. However, the variations in DOM and DBP precursors in deep-water reservoirs during algal bloom remain unclear. UV and fluorescence spectroscopy and chlorination experiments were used to analyze the variations in DOM and DBP precursors during algal bloom in the Sanhekou Reservoir. Before algal bloom, the DOM and DBP precursors decreased due to biodegradation. After algal bloom, the DOM and DBP precursors increased by 48.3% and 86.9% due to algae producing protein-like compounds. Notably, the algal bloom produced a range of nitrogenous compounds that significantly promote the formation of trichloronitromethane, a major contributor to the mammalian cytotoxicity associated with DBPs. In addition, the heterogeneous matrix led to the stratification of DOM and DBP precursors. The surface water (0-5 m) was more vulnerable to algae, with protein-like components being much higher than in other layers, while humic and fulvic-like components were much lower. However, high temperatures and sufficient oxygen conditions accelerated the biodegradation of DOM and DBP precursors, resulting in significantly lower levels of DOM and DBP precursors in the surface water compared to other layers (p<0.05). This study provides insights into the variations and the drivers in DOM and DBP precursors during algal bloom, essential for developing water intake strategies in similar water reservoirs.

Study on CO2-Enhanced Oil Recovery and Storage in Near-Depleted Edge–Bottom Water Reservoirs

The geological storage of carbon dioxide (CO2) is a crucial technology for mitigating global temperature rise. Near-depleted edge–bottom water reservoirs are attractive targets for CO2 storage, as they can not only enhance oil recovery (EOR) but also provide important potential candidates for geological storage. This study investigated CO2-enhanced oil recovery and storage for a typical near-depleted edge–bottom water reservoir that had been developed for a long time with a recovery factor of 51.93%. To improve the oil recovery and CO2 storage, new production scenarios were explored. At the near-depleted stage, by comparing the four different scenarios of water injection, gas injection, water-alternating-gas injection, and bi-directional injection, the highest additional recovery of 3.62% was achieved via the bi-directional injection scenario. Increasing the injection pressure led to a higher gas–oil ratio and liquid production rate. After shifting from the near-depleted to the depleted stage, the most effective approach to improving CO2 storage capacity was to increase reservoir pressure. At 1.4 times the initial reservoir pressure, the maximum storage capacity was 6.52 × 108 m3. However, excessive pressure boosting posed potential storage and leakage risks. Therefore, lower injection rates and longer intermittent injections were expected to achieve a larger amount of long-term CO2 storage. Through the numerical simulation study, a gas injection rate of 80,000 m3/day and a schedule of 4–6 years injection with 1 year shut-in were shown to be effective for the case considered. During 31 years of CO2 injection, the percentage of dissolved CO2 increased from 5.46% to 6.23% during the near-depleted period, and to 7.76% during the depleted period. This study acts as a guide for the CO2 geological storage of typical near-depleted edge–bottom water reservoirs.

Exposure to Pyriproxyfen Impacts Heart Development Causing Tissue and Cellular Impairments, Heart Arrhythmia and Reduced Embryonic Growth.

In recent years, concerns have been raised regarding the safety of exposure topyriproxyfen (PPF), a larvicide commonly used in drinking water reservoirs to control populations of disease-vector mosquitoes for human safety. These concerns are focused mainly on exposure by pregnant women, since studies have shown deleterious effects of PPF on embryonic development, mainly addressing the central nervous system. However, since previous studies showed reduced growth in embryos exposed to PPF, we hypothesize that PPF exposure impairs the cardiovascular system, responsible for ensuring appropriate blood supply, which leads to stunted growth. This study aimed to investigate the impact of PPF exposure on heart ventricular morphology, its influence on cell proliferation and apoptosis, as well as assess the impact on the functionality of the heart and on embryonic growth. Chicken embryos were used as a model and two sublethal concentrations were tested: 0.01mg/L and 10mg/L PPF. Thinning of cardiac tissue was evident in heart structuresat 10mg/L PPF. Furthermore, DNA double-strand breaks and reduced cell proliferation were observed, combined with decreased apoptosissuggesting cell cycle arrest, especially in the left ventricle for both concentrations. In addition, these PPF concentrations induced heart arrhythmia, although no changes in heart rate were observed. Embryos exposed to 0.01mg/L showed reduced body and heart mass, crown-rump length, and thoracic perimeter, while head circumference was reduced in both exposed groups. Together, combining morphological, molecular, and physiological parameters, this study showed the cardiotoxic effects of PPF exposure and elucidated its impacts on embryonic growth.

A Review on Pyridine Based Colorimetric and Fluorometric Chemosensor for Detection of Hg2+ ion.

Pyridine, N-containing heterocyclic organic compound, displays strong coordination capabilities with various metal ions. It can be synthesized through various methods, such as Friedlander synthesis, heterocumulene synthesis, cross-coupling reactions, the Radziszewski reaction, Bonnemann cyclization, as well as cobalt-catalyzed synthesis. Experimental and spectroscopic analyses have demonstrated a strong binding affinity between pyridine and several heavy metal ions, including Pb2+, Hg2+, and Cd2+ ions. The escalating environmental pollution caused by the disposal of heavy metal ions in rivers, open air, and water reservoirs poses a significant threat to both ecosystem and human health. To address these environmental challenges, a cost-effective and easily synthesized chemosensor has been prepared for identifying toxic heavy metal ions in various samples. Pyridine's photophysical properties make it an effective sensor for detecting Hg2+ ions, displaying fluorescence quenching or enhancement in their presence. The coordination between pyridine and Hg2+ ions lead to shifts in the absorption spectra. The pyridine-based sensor has been evaluated for its sensitivity, selectivity, and detection limits under different experimental conditions. Pyridine's solubility and environmental stability make it applicable for real-time detection, making pyridine probes valuable tool for monitoring toxic Hg2+ ions in the environment. The results demonstrate that the pyridine-based chemosensor exhibits good selectivity and sensitivity for targeting Hg2+ ions, with detection limits within acceptable ranges. This review (from years 2011 to 2023) emphasizes the preparation of various substituted pyridine compounds as selective, sensitive, and specific sensors for real-time detection of Hg2+ ions.

Considerable declines in odor in a drinking water reservoir: Variations of odorous community, precursor enzymes abundance, distribution, and environmental dominant factors

The presence of 2-methylisoborneol (2-MIB) is acknowledged as a prevalent source of odor-related challenges in drinking water reservoirs. Among the three in situ experiments conducted in drinking water reservoir, the water-lifting aerator with bio-filling system exhibited the most pronounced overall effects. It achieved a remarkable 98.70 % removal of 2-MIB and a 99.30 % reduction in the abundance of the mic gene. Metagenomic sequencing identified key genes including methyl transferase gene (mtf), 2-MIB cyclase gene (mic), cyclic nucleotide-binding protein gene (cnb), underscoring the potential role of Actinobacteria, Cyanobacteria, and Proteobacteria communities in contributing to odor occurrences in the reservoir. Furthermore, the abundance of odorous precursor enzymes in the MVA pathway and MEP/DOXP pathway were inhibited in the systems with bio-filling. Total nitrogen (TN) and nitrate (NO3−-N) were identified as pivotal factors influencing the presence of 2-MIB odor-producing microorganisms. Effective management of odor-producing species in reservoir water was closely related to the efficient removal of pollutants. These findings will provide valuable insights for the development of odor removal techniques in reservoirs and offer researchers deeper understanding into the mechanisms underlying odor processes.