Search

Before hydrates can be widely used in industry, we should better understand the problematic issues of hydrate nucleation, particularly its stochastic nature. Here, we report on measurements of the nucleation probability of mixed-gas hydrates in which the guest molecules are a mixture of methane and propane. For the pure cases, at a supersaturation near 1.0, we had previously measured an induction time for the methane hydrate of about 1 h, whereas for the propane hydrate, it was over one day. Using the same experimental setup, we examine here the nucleation probability for a mixture of 90% methane and 10% propane as the guest gas for a range of supersaturations. For the experiments, the temperature was 274 ± 0.5 K and the stirring rate was about 300 rpm. The experiments were repeated at least ten times under the same condition, exchanging the sample water every time. We define the nucleation probability at a given time as the fraction of trials that nucleated by that time and then determine the nucleation probability distribution. The resulting nucleation frequency is found to have a power-law relation to supersaturation. Then, we examine how the nucleation frequency is affected by the existence of ultrafine bubbles in the initial water. We find that the ultrafine bubbles increase the nucleation frequency but much less than that of typical changes in supersaturation. [ABSTRACT FROM AUTHOR]

Hypochlorite (ClO−) is an important oxidant and disinfectant in the human body and in nature. Nevertheless, it may exert an adverse impact on the environment and biological systems when its concentration is not appropriate. It is necessary to develop an accurate method for detecting ClO−. Herein, an isopinocamphone-based fluorescent probe DMTI for selective recognition of ClO− was successfully synthesized. DMTI exhibited an obvious fluorescence enhancement towards ClO− accompanied by a color shift from colorless to bright blue. The experimental results displayed that the probe DMTI had the merits of high selectivity, good sensitivity, and a wide detection pH range (6–10) for ClO− detection, and the detection limit reached 2.6 × 10−7 mol L−1. The sensing mechanism of DMTI to ClO− was confirmed by the 1H NMR and HRMS analyses. More importantly, the probe DMTI has been effectively utilized to detect ClO− in environmental water samples, living cells and zebrafish encouraged by its excellent performance. [ABSTRACT FROM AUTHOR]

A modified carbon paste sensor based on N,N′-(((ethane-1,2-diylbis(oxy))bis(2,1-phenylene))bis(methanylylidene))bis(pyridine-2-amine; BPA Schiff base as Cr(III) selective carrier was fabricated and studied in this work. The proposed sensor homogenization and mechanism of action was studied by infra-red (IR) and scanning electron microscope (SEM) with energy dispersive X-ray (EDX) tools. The sensor covered 1.0 × 10−7–1.0 × 10–1 mol L−1 linear range and a detection limit of 7.22 × 10–8 mol L−1 for Cr(III) with 20.17 ± 0.13 mV decade−1 Nernstian slope. 5 s was the response time of the prepared sensor and it was reproducible and stable for 3 months. The working pH range was 3.3–6.0 and it also works well to determine Cr(III) ion in presence of water miscible solvents up to 12.5% content of the methanol and 17.5% of ethanol. The electrode's selectivity was studied using separate and mixed solution methods for selectivity coefficients determination and the sensor showed good selectivity relative to a variety of metal ions (selectivity coefficients = 1.01 × 10−5–8.57 × 10−3). In addition, the practical analysis value of the sensor was demonstrated by measurement of Cr(III) quantitatively in mineral water, supplement and also as an indicator electrode in Cr(III) against EDTA potentiometric titration with good reproducibility (RSDs of 0.91–2.15%). [ABSTRACT FROM AUTHOR]

The transport of plankton by highly dynamic (sub)mesoscale currents—often associated with fronts and eddies—shapes the structure of plankton communities on the same time scales as biotic processes, such as growth and predation (days–weeks). The resulting biophysical couplings generate heterogeneities in their finescale distributions (1–10 km), or “patchiness.” Here, we test the hypothesis that cross‐frontal plankton patchiness at a front found 200–250 km offshore in the California Current System was influenced by wind‐driven upwelling conditions upstream of the front. We show that in situ Eulerian measurements (cross‐frontal transects) can be interpreted in a Lagrangian framework by using satellite‐derived current velocities to trace water parcels backward in time to their coastal origins. We find that the majority of the water parcels sampled at this front originated along the central California coast during different episodic wind‐driven upwelling pulses and followed various trajectories before converging temporarily at the front. In response to nutrient injections at the coast, plankton communities transformed during their journeys from the coast to the sampling zone, with a succession of phytoplankton and zooplankton blooms. The cross‐frontal sampling captured the convergence of these distinct water parcels at different points in their biological histories, which resulted in the observed spatial patchiness. Our results suggest that identifying the processes controlling frontal plankton communities requires understanding them in the context of their spatial and temporal histories. In particular, Lagrangian approaches should be more widely applied to understand critical ecological patterns in highly dynamic systems. [ABSTRACT FROM AUTHOR]

Secondary microbial methane could provide a valuable energy source if it were better understood. Although coal seam is an ideal environment for investigating secondary microbial methane, there are few studies to trace the secondary microbial methane of high-rank coals. Here, we collected co-produced water samples from coalbeds in the Qinshui Basin (China) and analyzed the microbial community structure by 16S ribosomal RNA (16S rRNA) amplicon sequencing analysis. 16S rRNA sequencing demonstrated abundant methanogens in coalbeds including 6 orders (Methanobacteriales, Methanococcales, Methanofastidiosales, Methanomassiliicoccale, Methanomicrobiales, and Methanosarciniales) and 22 genera of methanogens. Superheavy DIC (δ13CDIC ranging from -4.2‰ to 34.8‰) and abundance of methanogenic microbes in co-produced water revealed the generation of secondary biogenic methane in high-rank coal seams in the Qingshui Basin. Hydrogenotrophic methanogenesis is the main pathway for secondary biogenic methane production. In deeply buried coal seams, biogenic methane is dominated by CO2 and H2 reduction methanogenesis, and in shallow buried coal seams, it may be produced synergistically by hydrocarbon degradation and hydrogenotrophic methanogenic microbes. The study discussed here is important for a better understanding of the generation of secondary microbial methane in high-rank coal. [ABSTRACT FROM AUTHOR]

Sertraline is used as an antidepressant drug for the treatment of psychiatric disorders, including anxiety and depression. In the current study, a simple and effective method was developed for the sensitive monitoring of sertraline in water samples using a GC–MS system. The spray-assisted droplet formation liquid-phase microextraction (SADF-LPME) method was used as a sample preparation method for the enrichment of analytes. Accordingly, dichloromethane was used as an extraction solvent and easily dispersed into a sample/standard solution using a lab-made modified spray device without using a dispersing solvent. The significant factors affecting the SADF-LPME efficiency, including sample pH, mixing conditions, extraction solvent type, and spray cycle, were univariately optimized to ascertain the extraction performance and applicability of the system. Under the optimized conditions, the plotted calibration curve of the method was linear in the range of 100.2–2011.7 µg/kg (mass-based standard preparation) with a good correlation coefficient (R2) of 0.9997. The detection and quantification limits of method were found to be 37.5 and 125 µg/kg, respectively. Validation of the method was successfully carried out using different tap water samples and applying a matrix-matching calibration strategy. The acceptable percent recoveries were recorded between 77.3 and 133.7%, with high repeatability. The recommended method is an alternative and fast extraction method with several advantages, including a simple experimental process, good dispersibility, and fast and superior extraction performance. It can be readily applicable to the monitoring and quantification of sertraline in tap water samples with good precision and accuracy. [ABSTRACT FROM AUTHOR]

AbstractThe pH value is an important indicator for determining water quality, and visible near-infrared (Vis-NIR) spectroscopy is an ideal technique for rapid detection. The Vis-NIR spectrum of water is greatly affected by temperature. When using Vis-NIR spectroscopy to detect the pH value of water, temperature interference will affect the prediction accuracy of the water pH value. In this study, several chemometric methods developed in recent years were used to correct the spectra of distilled water samples under temperature interference to improve the prediction accuracy of water pH values. Specifically, this includes the external parameter orthogonalization (EPO) algorithm and the generalized least square weighting (GLSW) algorithm. Spectra of distilled water samples at different temperatures in the 400–1049 nm range were collected, and the correction effects of the EPO algorithm and the GLSW algorithm on the spectra after temperature changes, as well as the prediction errors of water pH values, were tested and examined, compared with traditional full-temperature spectral correction models. The results show that both the EPO algorithm and the GLSW algorithm methods require only a small number of representative samples to obtain filtering matrices. By correcting the spectra of distilled water samples at all temperatures to the reference temperature level, good correction effects can be achieved. Additionally, the prediction accuracy of water pH values of the models corrected by both methods is better than that of the traditional method, and the complexity of the models is also greatly reduced. [ABSTRACT FROM AUTHOR]

This work outlines the development of a voltammetric method for a sensitive, rapid, and environmentally friendly determination of the antihypertensive sotalol (SOT) in several sample types employing the anodically pretreated boron‐doped diamond electrode. Cyclic voltammograms of SOT presented a well‐defined irreversible oxidation peak at 1.21 V (Ag/AgCl (3.0 mol L−1 KCl)) in Britton–Robinson buffer solution (pH 3.0). Figures of merits recommended by the validation guidelines were evaluated for the validation of the present method. Employing differential pulse voltammetry linearity of SOT was obtained in the concentration range of 0.39–4.22 μmol L−1 in 0.1 mol L−1 H2SO4 solution, with a limit of detection of 0.031 μmol L−1. The selectivity of the method was assessed against interferers and show relative standard deviation (RSD) values lower than 6 %. Recovery tests yielded percentages ranging from 93 % to 96 % in urine sample and from 100 % to 107 % in tap water sample. The proposed method was successfully applied in pharmaceutical, environmental, and biological samples offering a suitable green analytical chemistry profile. [ABSTRACT FROM AUTHOR]

This paper presents a novel dispersive liquid–liquid microextraction (DLLME) method that employs solidified hydrophobic deep eutectic solvent (DES) with hydrophilic DES acting as the dispersant. The aim is to enrich polychlorinated biphenyls (PCBs) from water samples for subsequent determination by gas chromatography–mass spectrometry. The effects of both the hydrophobic DES as the extractant and the hydrophilic DES as the dispersant were thoroughly investigated. Optimization of the key factors influencing extraction efficiency was performed, and the method was subsequently validated. Specifically, a hydrophobic DES called DES2, prepared by combining thymol and decanoic acid in a molar ratio of 3:2, was selected as the extraction solvent. Meanwhile, a hydrophilic DES named DES6, prepared from choline chloride and acetic acid in a molar ratio of 1:2, was chosen as a dispersant. Under the optimal extraction conditions, the developed method exhibited excellent linearity over the concentration range of 0.01–5.0 µg/L, low limits of detection ranging from 3.0 to 5.1 ng/L, relative standard deviations less than 4.1%, and enrichment factors between 182 and 204 for PCBs. Finally, the effectiveness of the developed method was successfully demonstrated through residue determination of PCBs in water samples. [ABSTRACT FROM AUTHOR]

Global warming can affect biomass accumulation and the dynamics of periphytic communities, potentially altering their role in aquatic ecosystem functioning. We conducted a 38-day mesocosm experiment to investigate the effects of an increase in winter temperature on periphyton biomass accumulation under eutrophic conditions. We evaluated the warming effect on colonization phases, identifying the most affected phase. The experiment had two treatments (control: current winter temperature of 23.5 ℃, warming: + 5.7 ℃ under IPCC scenario). It was carried out in growth chambers under controlled temperature, light, and humidity. Periphyton and water samplings were performed on days 3, 6, 9, 13, 17, 21, 27, and 38. The increase in temperature did not affect the organic matter accrual rate of the periphyton. However, it negatively affected the net and gross accrual rate of the algal biomass. Ash-free dry mass and chlorophyll-a ratio in the periphyton increased at higher temperatures, indicating a decrease in autotrophic components in the periphyton in the warming treatment. We detected losses in algal biomass during the intermediate and advanced colonization phases. Our results showed a decrease in periphytic algal biomass with an increase in average temperature in winter. In conclusion, a warming scenario can negatively influence periphyton biomass in eutrophic ecosystems, where algal growth in the community is generally unfavorable. [ABSTRACT FROM AUTHOR]

A new method using fluorescence was developed to detect Hg2+ ions in water. This method relied on the reaction between NH2‐MIL‐53(Al) and 5‐bromo‐2‐hydroxyacetophenone. The method was carefully fine‐tuned for optimal reaction conditions and analytical parameters like pH levels, nanosensor quantity, and detection limits. It showed great linearity in detecting Hg2+ ions in the range of 0.0–3.0 ppm (0.0–1.50 × 10−5 M), with a very low detection limit of 1.65 × 10−2 ppm (8.23 × 10−8 M). We tested how well the method can distinguish between different substances by investigating whether other common substances in water samples would interfere. The results were positive, as the presence of these substances did not significantly affect the accuracy of detecting Hg2+ ions, confirming the method's reliability. In order to confirm its dependability, we conducted a quantitative test to detect Hg2+ ions in water samples. The recovery rates obtained ranged from 97.16% to 103.2%, demonstrating the method's precision and accuracy. A comparison with inductively coupled plasma optical emission spectrometry (ICP‐OES), a well‐known method for analyzing trace metals, produced similar results, further instilling confidence in the 5Br2HA = N‐Al‐MOF nanosensor that was developed. In general, this research emphasizes the exciting potential of the new nanosensor in detecting Hg2+ ions in various water and cosmetic samples. It provides a strong and dependable alternative to traditional detection methods. [ABSTRACT FROM AUTHOR]

Fenuron (FEN) is a herbicide that acts as a weed growing inhibitor in crops. Because of its persistence and good solubility in water, its presence in water bodies is emerging as a concern for aquatic species. Herein, we propose a simple development of an electrochemically reduced graphene oxide (rGO) sensor for the monitoring of FEN in environmental water samples. The rGO modified electrode was produced by cyclic voltammetry in a graphene oxide (GO) dispersion under constant stirring. The successfully synthesized rGO showed improved conductivity, electroactive surface area, and faster charge transfer compared to GO and glassy carbon (GC). Scanning electron microscopy images exhibited more frequent wrinkles in the morphology of the reduced form of the carbonaceous material, which is related to a defect-richer structure, as confirmed by Raman spectroscopy. The electrochemical determination of FEN showed the best performance in a 0.1 mol L−1 NaCl solution (pH = 2.5). Optimized parameters in differential pulse voltammetry of FEN resulted in two linear ranges (0.4–12.0 µmol L−1 and 20.0 to 50.0 µmol L−1) with high sensitivities of 6.83 and 1.90 µA µmol−1 L, respectively, and a low LOD of 0.34 µmol L−1. Stability, reproducibility, and interference tests proved the reliability of rGO in sensing FEN in real samples. Spiked tap and canal water samples returned recoveries close to 100%, exhibiting no statistically significant difference when compared to UV-Vis method by an average paired t-test, attesting the viability of the rGO modified electrode as a promising sensor of FEN in environmental water samples. [ABSTRACT FROM AUTHOR]

A novel electrochemical sensor based on multiwalled carbon nanotubes (MWCNTs) and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) hydrophobic ionic liquid for the rapid detection of Pb2+ and Cd2+ was developed. In this study, the BMIMPF6-MWCNTs composite, as well as BMIMPF6 and MWCNTs, were characterized using SEM. The electrochemical studies were performed using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). The BMIMPF6-MWCNTs/GCE exhibited excellent electrochemical activity. The effect of the pH value of 0.1 M NaAc/HAc buffer, deposition potential, and deposition time was investigated. Under the optimal conditions, the linear range for the modified sensors varies from 5 to 1850 µg L−1 for Pb2+ and 22 to 600 µg L−1 for Cd2+. The limit of detection (LOD) for Pb2+ and Cd2+ was 0.9 µg L−1 and 0.5 µg L−1, respectively, and the limit of quantification (LOQ) was 3 µg L−1 for Pb2+ and 1.7 µg L−1 for Cd2+. Moreover, this method showed excellent anti-interference performance, short analysis time, and practicability for determining Pb2+ and Cd2+. The electrochemical sensor was able to determine heavy metal ions in actual water samples without complex pretreatment, with acceptable recoveries from 98 to 110.8% for Pb2+ and 98.6 to 111.3% for Cd2+, demonstrating that the sensor based on BMIMPF6-MWCNTs/GCE can apply for Pb2+ and Cd2+ quantification. [ABSTRACT FROM AUTHOR]

For the first time, a highly permeable nanoporous carbon derived from melamine-based polybenzoxazine (NPC-PBZ-m) was used as the solid-phase extraction sorbent for trace analysis of atrazine (ATZ) herbicide in environmental water samples as a pre-treatment to enhance detection for high-performance liquid chromatography. Extraction performance was investigated using an agricultural field matrix-water sample. The parameters affecting the solid-phase extraction efficiency were carefully investigated. The optimisation conditions were determined as 200.0 mg of sorbent with an adsorption flow rate of 10.0 mL min−1, an elution flow rate of 1.0 mL min−1, and an elution volume of 3.0 mL. Moreover, it was not necessary to adjust the pH of the sample. Under these optimised extraction conditions, good linearity between 5.00 and 30.0 µg L−1 was achieved along with a limit of detection (LOD) of 1.25 µg L−1 and a limit of quantification (LOQ) of 3.79 µg L−1. Furthermore, the reusability of the NPC-PBZ-m column was found up to 8 cycles making it a new cost-effective material for herbicide enrichment. Finally, this developed method was successfully applied to analyse ATZ in water samples from rice fields, fish farms, and natural canal water, with 98–117% relative recoveries. These results indicate that NPC-PBZ-m with our proposed method is feasible and demonstrates its potential application as an effective adsorbent for herbicide enrichment. [ABSTRACT FROM AUTHOR]

To prepare a magnetic nano-adsorbent for efficient and fast removal of a dye, especially if present in trace concentration, along with a facile green synthetic methodology is a great challenge. The present work realises this task by combining the well-known advantages of both solvent-free microwave approach, nanoscale particle size and the fast magnetic separation. Thus, silica-coated magnetite nanoparticles (Fe3O4 NPs@SiO2) as an important precursor were produced directly via an optimised solid-solid interaction between silica and Fe3O4 NPs at 200 watt of microwave irradiation for only 10 min. The as-developed adsorbent was characterised using Fourier Transform Infrared (FT-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX) analysis. Its performance with no further modification for removal of Methylene blue (MB) dye from aqueous solution was achieved in a batch mode as a function of pH, contact time, adsorbent dose and initial dye concentration. The results demonstrate excellent removal efficiency (98.9%) within 5 min, as compared with recent adsorbents synthesised through a multi-steps reaction. Modelling of the experimental data denoting well-fitting with both Langmuir sorption isotherm (monolayer capacity 47.98 mg/g) and pseudo-second-order kinetic model. A possible MB binding mechanism has been proposed taking in account values of dissociation constants of the different forms of silica surface silanol groups. The adsorbent after first was successfully regenerated in situe for five consecutive cycles. Moreover, it was proved to be valid for collecting efficiently trace concentrations of MB spiked environmental water samples to be in the range 92.4–98.8%. [ABSTRACT FROM AUTHOR]

The occurrence and persistence of rotaviruses in raw and treated wastewater and their discharge into rivers represent a significant health risk for humans and animals, worldwide. In this study, samples were collected monthly from each of the four Durban wastewater treatment plants (DWWTPs) and receiving rivers for a period of 3 months. Rotavirus was quantified by real-time quantitative PCR (RT-qPCR), and viability was assessed using integrated cell culture (ICC)-qPCR. Rotavirus was detected consistently in 100% of influent wastewaters (mean concentration range, 4.36–4.46 log10 genome equivalent (GE) copies/L) and final effluent samples of three DWWTPs (range, 3.35–3.61 log10 GE copies/L). Overall, 94% (45/48) of the wastewater analyzed and 95% (20/21) of the associated river water samples were positive for rotavirus (range, 2.04–6.77 log10 GE copies/L). The activated sludge process with 0.10–0.43 log10 reduction values (LRV) only moderately reduced the viral loads. Similarly, one of the DWWTPs that operated the biofilter modality produced 0.20 LRV. Though the additional treatment with chlorine produced higher LRV (range, 0.31–0.53) than the corresponding activated sludge or biofilter process, the difference in viral removals was not significant (p > 0.05). The equivalent treatment efficiencies of the four DWWTPs varied from 19 to 43% decay in the population of rotavirus. Further, infectious rotavirus ranging from 66.67 to 100%, 50 to 100%, and 66.67 to 100% were detected in the post-activated sludge, final effluents, and river water samples, respectively. In conclusion, the findings of infectious rotavirus in both the final effluents and associated rivers represent an infection risk for humans or animals during contact. Thus, close monitoring for rotavirus and risk assessment studies under distinct exposure scenarios may further shed light on the health-related risks associated with water recovery and reuse in urban settings. [ABSTRACT FROM AUTHOR]

Microplastic (MP) pollution has been observed in various ecosystems as a result of the rapid increase in plastic production over the past half-century. Nevertheless, the extent of MP pollution in different ecosystems, particularly in freshwater ecosystems, has not been well-studied, and there are limited investigations on this particular topic, specifically in Türkiye. Here, we quantify the occurrence and distribution of MPs in surface water samples collected from Topçu Pond (Türkiye) for the first time. Water samples were collected at five stations and filtered (30 L for each station) through stacked stainless steel sieves (5 mm, 328 µm, and 61 µm mesh size) with a diameter of 30 cm. The abundance, size, color, shape, and type of collected debris samples were analyzed after the wet peroxide oxidation process. MP particles were observed in all samples at an average abundance of 2.4 MPs/L. The most abundant MP size class and type were 0–999 µm and fiber respectively. On the other hand, prevalent colors were black and colorless in general. According to the Raman analysis results, the identified MP derivatives were polypropylene (40%), polyamide (30%), ethylene acrylic acid (20%), and polyvinylchloride (10%). Moreover, the pollution load index (PLI) index was used to determine the pollution status. PLI values were determined as 1.91 at station S1, 1.73 at station S2, 1.31 at station S3, 1 at station S4 and 1.24 at station S5. The PLI value determined for the overall pond was 1.4. The results of this research show that MP pollution is present in Topçu Pond and contributes to the expanding literature on MP pollution in pond ecosystems. [ABSTRACT FROM AUTHOR]

With a growing need for efficient use of water in a large metropolitan community, a municipal water district has developed an experiential educational programme to help customers develop acceptance of purified recycled water (PRW). This programme involves touring a small‐scale working purification facility that does not provide consumer drinking water but serves as a demonstration centre. Two empirical studies demonstrated the positive impact of this educational program. In Study 1, a pre‐/post‐research design was used to examine scores on a measure of attitudes about PRW for 70 undergraduate students who were asked to tour the demonstration centre. These participants expressed more favourable attitudes after the tour than they expressed before the tour (t = 8.76, df = 68, p < 0.001, d = 1.06), suggesting that the demonstration centre positively impacted attitudes about PRW. In Study 2, an experimental design allowed for a comparison of attitudes about PRW for undergraduate students who were given an informational tour of the demonstration centre (n = 27), compared to students who did not tour the demonstration centre until after their data were collected (n = 30). Participants who toured the demonstration centre expressed more positive attitudes on a self‐report measure of PRW attitudes than those who had not completed the tour (t = 2.24, df = 50.0, p = 0.03, d = 0.60); however, the two groups did not differ in the amount of water they sampled (t = 0.29, df = 55.65, p = 0.77, d = 0.08) or in facial expressions associated with happiness (t = 1.34, df = 53.89, p = 0.19, d = 0.38) or disgust (t = 0.86, df = 53.14, p = 0.40, d = 0.39) when drinking a sample of water. Together, these studies demonstrate the effectiveness of an experiential demonstration centre in increasing positive attitudes towards purified recycled water. Highlights: A municipal water district developed a demonstration centre to educate the local community about the upcoming inclusion of purified recycled water.In Study 1, attitudes about purified recycled water were more accepting after participating in an experiential tour.In Study 2, attitudes held by those who participated in the tour were more positive than attitudes of the control group.These studies suggest that an experiential educational programme has a positive impact on attitudinal acceptance of purified recycled water. [ABSTRACT FROM AUTHOR]

The present study is conducted to assess the water quality of Sorbhog Beel for determining its usability for different activities. In order to understand the overall surface water quality of the Beel, water samples were collected from four sampling stations (S1, S2, S3 and S4) which are located at equal distances from each other. Sampling of the Beel was carried out for a period of one year from December 2020 to November 2021, covering four seasons of the year. Water samples were analyzed for eleven important physicochemical parameters viz. pH, Total Dissolved Solids (TDS), turbidity, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Total Hardness (TH), calcium, magnesium, chloride, nitrate and sulphate. Results of the physicochemical analysis were compared with the standard limits prescribed by Bureau of Indian Standard's specification for drinking water, which showed that physicochemical parameters at all the four sampling stations were within the permissible limits except for TDS. Parameters except Nitrate displayed significant positive and negative correlation among each other. Based on the calculated values of the physicochemical parameters, Water Quality Index (WQI) value of the Beel ranged between 63.59 in pre monsoon season to 71.14 in monsoon season, indicating that water samples were of 'poor' quality throughout the year in all the four stations, with maximum deterioration at station S1. The water of the Beel, therefore, cannot be utilized for drinking purpose without prior treatment, however, it can be used for other purposes such as irrigation and industry. [ABSTRACT FROM AUTHOR]

Increased mismanaged plastic has led to widespread microplastic (MPs) contamination in the marine environment. Our study investigates MPs across the inner, outer, and mangrove regions of the Kollidam River estuary on the east coast of India. Surface water and sediment samples at 18 locations were analysed for size, shape, colour, and polymer type. The average MP abundance in surface water and sediment was 2.42 particles. m−3and 1580 ± 705 particles. kg−1d.w. respectively. The predominant polymer types observed were PP (40%), PE (26%), and PAc (24%). Medium-sized particles (1–2.5 mm) are more in surface water (44%), and small-sized (0.01–1 mm) particles dominate in sediment samples (50%). The most common MP shapes were fibres and fragments, with transparent MPs being the most frequently observed colour. The results highlight that the mangrove region acts as a potential sink for microplastic pollution. [ABSTRACT FROM AUTHOR]

Methane (CH4) dissolved in water is readily consumed by CH4‐oxidizing bacteria, so the possibility of the dissolved CH4 concentration (dCH4) in sampled water changing before analysis is a concern. To determine the accurate in situ dCH4 level, mercury chloride (HgCl2) or sodium azide (NaN3) is traditionally used for sample preservation. However, these preservatives are very toxic and great care must be taken when adding them to samples. Benzalkonium chloride (BAC), a quaternary ammonium salt cationic surfactant, is a readily available disinfectant that is less harmful to the human body than HgCl2, NaN3, and other preservatives. In this study, we investigated the usefulness of BAC in preserving dCH4 in swamp water, which is a critical terrestrial source of CH4. The dCH4 in samples without BAC decreased immediately after sample collection, whereas the dCH4 in the samples with added BAC did not change significantly for at least 15 d. In addition, when BAC was added to 18 water samples with different water chemistries, the dCH4 did not change significantly from immediately after sampling to 1 week after sampling (average difference: 3%). Thus, in the water samples used in this study, BAC effectively preserved dCH4 in the samples for at least 1 week. Further testing of the effect of BAC on the preservation of dCH4 in different types of water samples worldwide will help to establish a more complete, simple, and safe method. [ABSTRACT FROM AUTHOR]

The ASI algorithm uses the same sea ice and seawater tie-points when inverting polar sea ice concentration (SIC), but this approach does not fully consider the differences between different polar sea regions and the impact of different sea ice characteristics on SIC results. To make up for this deficiency, the SIC inversion algorithm based on different types of Arctic sea ice is proposed. The proposed algorithm selects pure ice and pure water sample points in different sea regions to derive SIC inversion formulas, and subsequently obtains SIC retrieval results for the entire Arctic. Compare the results of this study with those of traditional ASI algorithm, and perform local validation based on the sea ice distribution obtained from Landsat-8 data. The results show that compared with the traditional ASI algorithm, the proposed algorithm has improved the accuracy of SIC inversion in different sea ice regions by 2%-6%, with an average improvement of 3.3%. Overall, our research has improved the ASI algorithm, which is of great significance for obtaining higher precision polar SIC. [ABSTRACT FROM AUTHOR]

Molecularly imprinted materials based on imprinting dithizone‐Zn (II) (DTZ‐Zn (II)) complexes onto cotton fabric/silica, and the Color Grab application for the OPPO A54 smartphone, were proposed and applied for the first time to detect Zn (II) ions in water samples. The proposed materials were prepared by using cotton fabrics as cellulosic materials, tetraethoxysilane as silica sources and DTZ‐Zn (II) as template molecules. The initial concentration of DTZ and Zn (II), the volume of tetraethoxysilane and the reaction time were optimised to obtain the maximum adsorption of the DTZ‐Zn (II) complexes in the imprinted materials. The concentration of hydrochloric acid and the extraction time were optimised to obtain the maximum Zn (II) removal. The results found that 10 mL of a solution containing DTZ (0.20 mM) and Zn (II) (0.30 mM), 25 μL of tetraethoxysilane, with 10 minutes reaction time, exhibited the strongest binding of the template complexes. Zn (II) ions were selectively removed from the materials by using 0.1 M hydrochloric acid for 10 minutes. The morphology of the prepared materials was characterised by scanning electron microscopy–energy‐dispersive X‐ray spectroscopy and attenuated total reflectance–Fourier Transform‐infrared spectroscopy. The smartphone measurement based the cotton fabric/silica materials exhibited linear relationship between saturation (%) and Zn (II) concentrations in the range of 0.1 to 1.0 mg/L, with limit of detection of 0.02 mg/L and limit of quantification of 0.06 mg/L. The proposed method was successfully applied to determine Zn (II) in real‐water samples with the % recovery ranging from 98% to 115% and an acceptable relative standard deviation of less than 6 (n = 3). [ABSTRACT FROM AUTHOR]

Microalgae are a highly effective and renewable source of biodiesel that can be used as a substitute for petro-diesel in the global fuel market. In the present study, 14 water samples were collected from a variety of locations along the coastal areas of the Red Sea and the Mediterranean Sea in Egypt. These water samples, which contained microalgae, were subjected to enrichment process and standard procedures to obtain pure cultures. Based on morphological features, 27 microalgae isolates representing 12 different species were identified, with Chlorella species being the most dominant. Based on 18s rRNA gene sequencing, nine new native microalgae strains were identified, comprising four strains belonging to Chlorella species, two strains to Chlamydomonas, and one strain each of Phormidium, Nostoc, and Microcytosis species that could be appropriate for producing biodiesel. This information could be used to improve the knowledge on the composition of planktonic microalgal communities of Egypt and the target native species for biodiesel production. [ABSTRACT FROM AUTHOR]

In this study five different complexes of Cu(II) were synthesized for the purpose of environmentally notorious mercury sensing and preliminary biological screening. Pyridine‐2,6‐dicarboxylic acid (also known as dipicolinic acid, and abbreviated as H2DPA), 3‐phenyl pyrazole (3‐ppz), 4‐iodo‐1H‐pyrazole (4‐ipz), 4‐nitropyrazole (4‐npz), 4‐bromopyrazole (4‐bpz), and 4‐chloropyrazole (4‐cpz) were chosen as potential ligands. The synthesized complexes labelled as 1–5, namely [Cu(DPA)(3‐ppz)], [Cu(DPA)(4‐ipz)], [Cu(DPA)(4‐npz)], [Cu(DPA)(4‐bpz)], [Cu(DPA)(4‐cpz)], were proposed based on spectroscopic data (FTIR, TGA, and UV‐visible spectroscopy). These complexes feature C=O functionalities that are not involved in coordination and may be used for further applications. The isolated complexes were utilized for detecting Hg(II) ions in water samples. Various concentrations of Hg(II) ions were prepared for detection purposes, and changes in absorption concerning complexes 1–5 were determined using UV‐Visible spectroscopy. It was found that complexes 3 and 4 exhibit efficient sensing abilities towards Hg(II) ions. The antibacterial activities of complexes 1–5 were assessed against S. typhi and E. coli. The complexes 1 and 3 displayed good antibacterial activities against S. typhi (13.67, and 13.56 mm, respectively) while complexes 1, 2 and 4 were found to be efficient against E. coli (11.6, 12.66, 11.31 mm, respectively). The absorption maxima of 2,2‐diphenyl‐1‐picryhydrazyl (DPPH) at 517 nm, considerably shifted upon addition of complexes 1–5. The results reveal that the complexes possess potential free radical scavenging abilities. [ABSTRACT FROM AUTHOR]

In the evolving field of food safety, rapid and precise detection of antibiotic residues is crucial. This study aimed to tackle this challenge by integrating advanced inkjet printing technology with sophisticated microfluidic paper‐based analytical devices (µPADs). The µPAD design utilized “green” quantum dots synthesized via an eco‐friendly hydrothermal method using green white mulberry leaves as the carbon source, serving as the key fluorescent detection material. The action mechanism involved a photoinduced electron transfer system using red carbon dots (CDs) as electron donors and blue CDs combined with two‐dimensional layered molybdenum disulfide (MoS2) nanosheets as electron acceptors. This system could quickly detect antibiotics within 10 min in pork and water samples, demonstrating high sensitivity and recovery rates: 6.5 pmol/L at 99.75%–110% for sulfadimethoxine, 3.3 pmol/L at 99%–105% for sulfamethoxazole, and 8.5 pmol/L at 98.5%–105% for tetracycline. It achieved a relative standard deviation under 5%, ensuring reliability and reproducibility. The fabricated sensor offered a promising application for the rapid and efficient on‐site detection of antibiotic residues in food. [ABSTRACT FROM AUTHOR]

A novel ferrofluid prepared from a hydrophobic deep eutectic solvent (DES) and Fe3O4@graphite composite materials was introduced as a green microextraction medium for the separation and enrichment of trace estrogens in real samples. It was found that the ferrofluid greatly improved the capacity and selectivity of target analytes, benefiting from the enrichment of both DES and Fe3O4@graphite composite materials. Using a combination of high-performance liquid chromatography–fluorescence detection (HPLC-FLD) and vortex-assisted liquid–liquid microextraction (VALLME), a new method was established for simultaneous rapid processing and accurate determination of three estrogens (estradiol [E2], estriol [E3], and ethinyl estradiol [EE2]) in environmental water and urine samples. Key parameters affecting the extraction efficiency were optimized using a single-factor approach and response surface methodology. Under optimal conditions, this method yielded a low limit of detection (1.01 ng L−1, 3.03 ng L−1, and 25.0 ng L−1 for EE2, E2, and E3, respectively), wide linear range (3–200,000 ng L−1), high enrichment factors (9.81–47.2), and satisfactory recovery (73.8–129.0%). Compared with traditional analytical techniques, this method avoids the use of volatile toxic organic extraction solvents and cumbersome phase separation operations. [ABSTRACT FROM AUTHOR]

The study of microalgal communities is critical for understanding aquatic ecosystems. These communities primarily comprise diatoms (Heterokontophyta), with two methods commonly used to study them: Microscopy and metabarcoding. However, these two methods often deliver different results; thus, their suitability for analyzing diatom communities is frequently debated and evaluated. This study used these two methods to analyze the diatom communities in identical water samples and compare the results. The taxonomy of the species constituting the diatom communities was confirmed, and both methods showed that species belonging to the orders Bacillariales and Naviculales (class Bacillariophyceae) are the most diverse. In the lower taxonomic levels (family, genus, and species), microscopy tended to show a bias toward detecting diatom species (Nitzschia frustulum, Nitzschia inconspicua, Nitzschia intermedia, Navicula gregaria, Navicula perminuta, Navicula recens, Navicula sp.) belonging to the Bacillariaceae and Naviculaceae families. The results of the two methods differed in identifying diatom species in the communities and analyzing their structural characteristics. These results are consistent with the fact that diatoms belonging to the genera Nitzschia and Navicula are abundant in the communities; furthermore, only the Illumina MiSeq data showed the abundance of the Melosira and Entomoneis genera. The results obtained from microscopy were superior to those of Illumina MiSeq regarding species-level identification. Based on the results obtained via microscopy and Illumina MiSeq, it was revealed that neither method is perfect and that each has clear strengths and weaknesses. Therefore, to analyze diatom communities effectively and accurately, these two methods should be combined. [ABSTRACT FROM AUTHOR]

Biocomposting at national and regional levels has recently been recognized as one of the feasible, nature-based solutions to prevent the accumulation and reuse of biodegradable waste in enhanced and effective mitigation measures for urban and semi-urban waste management. Recent research has mainly focused on organic compost contamination, as the negative effects of MP on soil systems have been extensively studied. According to current research, organic compost used as fertilizer on farmland contains many microplastics. In this context, microplastics (MPs) have been regarded as a global environmental problem and an emerging soil contaminant. The physico-chemical properties of water and compost samples were analyzed by APHA and AOAC methods. The extraction of microplastics was done using the density separation. In the current study, agricultural waste-based biocompost and water samples used for the production of biocompost were collected from four different agricultural nurseries in semi-urban areas of the Coimbatore city. The physicochemical properties (including heavy metal content) of the biocompost and water samples tested were on par/equal/lower than Indian standards. Interestingly, in the biocompost samples, 85% of the microplastic fragments and 15% of the fiber types were identified only in BC-B and BC-C, respectively, with different colors such as red, brown, blue, light yellow and transparency. However, no microplastics were found in the biocompost samples of BC-A and BC-D. Microplastic polymers such as polymethyl methacrylate (PMMA), polypropylene (PP), and ethylene vinyl acetate (EVA) were identified through ATR-FTIR analysis. The results suggest that semi-urban agricultural gardening may lead to the accumulation of microplastics in terrestrial environments, which may negatively impact soil and plant health. This study contributes to growing research into microplastic contamination in organic compost and its potential impact on agriculture and terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

In this work, we test metal–organic frameworks (MOFs) as sorbents in the solid-phase extraction (SPE) technique to determine chemical warfare agents (CWAs) and their related compounds in water samples. During this study, we used 13 target compounds to test the selectivity of MOFs thoroughly. Three MOFs were used: MIL-100(Fe), ZIF-8(Zn), and UiO-66(Zr). The obtained materials were characterized using FT-IR/ATR, SEM, and XRD. CWA's and related compounds were analyzed using gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). The effect of the type of elution solvent and the amount of sorbent (MOFs) in the column on the efficiency of the conducted extraction were verified. The LOD ranged from 0.04 to 7.54 ng mL−1, and the linearity range for the analytes tested extended from 0.11/22.62 (depending on the compound) to 1000 ng mL−1. It was found that MOFs showed the most excellent selectivity to compounds having aromatic rings in their structure or a "spread" spatial structure. The best recoveries were obtained for DPAA, CAP, and malathion. Environmental water samples collected from the Baltic Sea were analyzed using an optimized procedure to verify the developed method's usefulness. [ABSTRACT FROM AUTHOR]

Background: Every year, 60% of deaths from diarrhoeal disease occur in low and middle-income countries due to inadequate water, sanitation, and hygiene. In these countries, diarrhoeal diseases are the second leading cause of death in children under five, excluding neonatal deaths. The approximately 100,000 people residing in the Bentiu Internally Displaced Population (IDP) camp in South Sudan have previously experienced water, sanitation, and hygiene outbreaks, including an ongoing Hepatitis E outbreak in 2021. This study aimed to assess the gaps in Water, Sanitation, and Hygiene (WASH), prioritise areas for intervention, and advocate for the improvement of WASH services based on the findings. Methods: A cross-sectional lot quality assurance sampling (LQAS) survey was conducted in ninety-five households to collect data on water, sanitation, and hygiene (WASH) coverage performance across five sectors. Nineteen households were allocated to each sector, referred to as supervision areas in LQAS surveys. Probability proportional to size sampling was used to determine the number of households to sample in each sector block selected using a geographic positioning system. One adult respondent, familiar with the household, was chosen to answer WASH-related questions, and one child under the age of five was selected through a lottery method to assess the prevalence of WASH-related disease morbidities in the previous two weeks. The data were collected using the KoBoCollect mobile application. Data analysis was conducted using R statistical software and a generic LQAS Excel analyser. Crude values, weighted averages, and 95% confidence intervals were calculated for each indicator. Target coverage benchmarks set by program managers and WASH guidelines were used to classify the performance of each indicator. Results: The LQAS survey revealed that five out of 13 clean water supply indicators, eight out of 10 hygiene and sanitation indicators, and two out of four health indicators did not meet the target coverage. Regarding the clean water supply indicators, 68.9% (95% CI 60.8%-77.1%) of households reported having water available six days a week, while 37% (95% CI 27%-46%) had water containers in adequate condition. For the hygiene and sanitation indicators, 17.9% (95% CI 10.9%-24.8%) of households had handwashing points in their living area, 66.8% (95% CI 49%-84.6%) had their own jug for cleansing after defaecation, and 26.4% (95% CI 17.4%-35.3%) of households had one piece of soap. More than 40% of households wash dead bodies at funerals and wash their hands in a shared bowl. Households with sanitary facilities at an acceptable level were 22.8% (95% CI 15.6%-30.1%), while 13.2% (95% CI 6.6%-19.9%) of households had functioning handwashing points at the latrines. Over the previous two weeks, 57.9% (95% CI 49.6–69.7%) of households reported no diarrhoea, and 71.3% (95% CI 62.1%-80.6%) reported no eye infections among children under five. Conclusion: The camp's hygiene and sanitation situation necessitated immediate intervention to halt the hepatitis E outbreak and prevent further WASH-related outbreaks and health issues. The LQAS findings were employed to advocate for interventions addressing the WASH gaps, resulting in WASH and health actors stepping in. [ABSTRACT FROM AUTHOR]

In the present study, a series of 2-amino-3-cyanopyridine-based enaminoates 2 were synthesized from substituted 2-amino-3-cyanopyridines 3 and ethyl cyclopentanone-2-carboxylate 4 in acetic acid. The synthesized compounds were characterized by using various techniques such as 1H NMR, 13C NMR, Mass, HRMS and FTIR. The photophysical properties of all the derivatives were investigated, including their absorption maxima, emission maxima and Stokes shift. Among these, compound 2e was investigated as a fluorimetric "turn-off" sensor for the selective detection of Fe3+. The interaction between 2e and Fe3+ was confirmed through Job's plot analysis and density functional theory (DFT) studies. The fluorimetric detection limit for Fe3+ reached up to 9.2 μM. Photostability and response time studies were also conducted to evaluate the analytical performance of 2e. Additionally, 2e was successfully applied for analyzing Fe3+ in real water samples such as lake water (Sukhna Lake, Chandigarh, India), distilled water and tap water using the standard addition method. Furthermore, 2e was employed to develop fluorimetric test strips for practical applications. [ABSTRACT FROM AUTHOR]

Zooplankton indicators based on rotifers (TSIROT) and an indicator based on Secchi disk visibility (TSISD) were used to assess trophic state changes in artificial, slow-flowing, and stagnant canal waters. The study was conducted in the summers of 2019, 2021, and 2022 in the Bydgoszcz Canal and the Noteć Canal (Poland). Water samples were taken from five sites once in the month of July and once in August. In terms of the species number and density, rotifers dominated among zooplankton (at almost all sites), which reflected the high trophic state. Our results showed statistically significant correlations between TSIROT and TSISD as well as between the individual indicators TSIROT1 (Rotifer numbers), TSIROT2 (Rotifer biomass), TSIROT3 (bacterivorous numbers of rotifers), TSIROT6 (rotifers indicating high trophic state), and TSISD. According to our study, the presented indices most likely determine the trends between TSIROT cumulative and TSISD in the studied canals. Similarly to previous studies performed on lakes and small reservoirs, zooplankton constituted a useful indicator of trophic state. It seems that, for stagnant and slowly flowing waters of canals such as the Bydgoszcz Canal and the Noteć Canal, the method of zooplankton trophic status indicators based on rotifers may be applied. [ABSTRACT FROM AUTHOR]

This study aims to apply the ionic liquid-based solidified floating organic drop micro-extraction (IL-SFODME) technique to improve the preconcentration of trace mercury levels, serving as a preparatory step for analysis via graphite furnace atomic absorption spectrometry (GFAAS) without using chelating agents. The process involves separating and preconcentrating mercury ions using IL-SFODME, followed by GFAAS analysis. This study systematically examined several factors affecting micro-extraction efficiency, including pH, the amount of ionic liquid 1-Hexyl-3-methylimidazolium hexafluorophosphate (HMIMPF6), extraction time, stirring rate, and temperature, to determine the optimal conditions. Under these optimized conditions, an enhancement factor of 171 was achieved for a 75 mL sample solution. The calibration curve was linear within the 0.5–10 µg/L range, with a detection limit (3σ) of 0.12 µg/L and a quantification limit (10σ) of 0.40 µg/L. The relative standard deviation (RSD) for 7 replicate measurements of 1 µg/L mercury was ±2.78%. The combination of the ionic liquid and SFODME methods without using a chelating agent is used for the first time for metal extraction. The method was successfully applied to extract and determine mercury in reference water samples and various real water samples, demonstrating notably satisfactory extraction efficiency. [ABSTRACT FROM AUTHOR]

Objective: The current research aimed to investigate the physicochemical and bacteriological quality status of the Kalte River in Wolaita Sodo Town, southern Ethiopia. Methods: A total of 42 water samples were collected using sterile glass bottles from three different river sites: Damota (upstream), Kera (midstream), and Gututo (downstream). All the water samples were examined for the presence of heterotrophic bacteria, total coliform and fecal coliform using direct plate count method and membrane filtration method. Standard methods suggested by American water works association were used to analysis the physicochemical parameters of the water samples. Results: The results revealed that the total heterotrophic bacteria, total coliform, and fecal coliform count ranged from 8.9 to 12.6 × 104 cfu/ml, 7.5–11.3 × 102 cfu/ml and 5.7–9.7 × 104 cfu/ml, respectively. The bacterial count results indicated that the river water crossed the WHO-recommended limit of potable water. Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella, and Shigella species were the common bacterial pathogens isolated from river water samples. The results of the physicochemical analysis revealed that some of the parameters Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and turbidity exceeded the maximum permissible limits of WHO and other parameters were below the WHO permissible limits. Conclusion: Therefore, the presence of bacterial pathogens, fecal coliform indicators, and some physicochemical parameters of the Kalte River exceeding the recommended limits may expose users of the river water to the risk of infection. [ABSTRACT FROM AUTHOR]

One effective option to minimize N-nitrosodimethylamine (NDMA) in finished drinking water is to identify and control its precursors. However, previous works to identify significant precursors use formation potential (FP) tests using high doses to assure the maximum NDMA formation rather than the NDMA formation in finished waters. In this study, we applied characteristic low treatment doses of ozone (O3)-to-dissolved organic carbon (DOC) of target compounds of 0.8 mg/mg and NH2Cl of 2.5 ± 0.2 mg Cl2/L to evaluate the NDMAFP yields of organic compounds bearing N,N-dimethylamine (DMA) and N,N-dimethylhydrazine (DMH) during preozonation and post-chloramination. The results in pH-buffered Milli-Q water showed a significant decrease from ≤ 52% to non-detectable levels in the O3-NDMAFP yields of O3-reactive precursors (i.e., DMH-like compounds) after preozonation and post-chloramination. Similarly, a significant decrease from 0.5 to 12% to nonquantifiable levels was observed for the NH2Cl-NDMAFP yields of NH2Cl-reactive precursors; however, the NH2Cl-NDMAFP yields of N,N-dimethylbenzylamine (DMBzA)-like compounds only decreased from ~ 110 to ≤ 43%, suggesting that these compounds could contribute to NH2Cl-NDMAFPs even after preozonation. The effect of the matrix in sewage-effluent and lake water samples varied and was specific for precursors; for example, the O3-NDMAFP yield of 1,1,1′,1′-tetramethyl-4,4′-(methylene-di-p-phenylene) disemicarbazide (TMDS), an important O3-reactive NDMA precursor, did not significantly decrease when tested in sewage-effluent samples. Based on the previous occurrence concentration of TMDS in sewage samples, we estimated an NDMAFP of ~ 315 ng/L. This estimate exceeds the guidance concentrations of NDMA (3–100 ng/L), highlighting the importance of TMDS and its related compounds for NDMA formation. [ABSTRACT FROM AUTHOR]

The generation of acid mine drainage (AMD) characterized by high acidity and elevated levels of toxic metals primarily results from the oxidation and dissolution of sulfide minerals facilitated by microbial catalysis. Although there has been significant research on microbial diversity and community composition in AMD, as well as the relationship between microbes and heavy metals, there remains a gap in understanding the microbial community structure in uranium-enriched AMD sites. In this paper, water samples with varying levels of uranium pollution were collected from an abandoned stone coal mine in Jiangxi Province, China during summer and winter, respectively. Geochemical and high-throughput sequencing analyses were conducted to characterize spatiotemporal variations in bacterial diversity and community composition along pollution groups. The results indicated that uranium was predominantly concentrated in the AMD of new pits with strong acid production capacity, reaching a peak concentration of 9,370 µg/L. This was accompanied by elevated acidity and concentrations of iron and total phosphorus, which were identified as significant drivers shaping the composition of bacterial communities, rather than fluctuations in seasonal conditions. In an extremely polluted environment (pH < 3), bacterial diversity was lowest, with a predominant presence of acidophilic iron-oxidizing bacteria (such as Ferrovum), and a portion of acidophilic heterotrophic bacteria synergistically coexisting. As pollution levels decreased, the microbial community gradually evolved to cohabitation of various pH-neutral heterotrophic species, ultimately reverting back to background level. The pH was the dominant factor determining biogeochemical release of uranium in AMD. Acidophilic and uranium-tolerant bacteria, including Ferrovum, Leptospirillum, Acidiphilium, and Metallibacterium, were identified as playing key roles in this process through mechanisms such as enhancing acid production rate and facilitating organic matter biodegradation. [ABSTRACT FROM AUTHOR]

In this study, the analysis of metals in tap, river, wastewater, and sludge samples was conducted using ICP−OES after hotplate- or microwave-assisted digestion. Both digestion methods produced a good degree of accuracy, indicating their suitability for the analysis of the studied metals in water samples. From method development studies, 100 mL of HNO3 was found to be the optimum sample volume and acid type for digestion. The average concentrations obtained ranged from 4.9–410.8 µg/L, 5.9–465.0 µg/L, 3.6–425.4 µg/L, 16.1–647 µg/L and 9.7–784 µg/L in tap water, river, influent, effluent, and sludge samples, respectively. All metals were below their maximum permissible limits, with the exception of Mn in all sludge samples and Pb in all tap water, Umhlathuzana River, and Northern Works influent samples. Comparable recoveries and metal concentrations were obtained by microwave and hotplate methods, suggesting that the cheaper hotplate method can be used as an effective digestion method for daily analysis. Common anion concentrations obtained ranged from 0.03–23.5 mg/L, 0.02–3 064.67 mg/L, and 0.32–175.67 mg/L for tap, river, and wastewater samples, respectively. The anion concentrations were found to be below the maximum acceptable limits indicating no negative health effect on human and aquatic life, with the exception of Cl− and SO4 2− in Amanzimtoti and Northern River water, respectively [ABSTRACT FROM AUTHOR]

The current study was conducted to use phytoplankton diatom to assess the quality of the Lower Zab River in Kirkuk province. Water samples were monthly collected from four sites along the Lower Zab River from September 2023 to April 2024. The selected sites were Sadr River Bridge, Ashraya, Al-Shamit, and Al-Shak villages. A total of 74 species of Bacillariophyceae were identified belonging to 18 genera. Five indices were applied to estimate the ecological status in the Lower Zab River. Diatom species were used as ecological bio-indicators. This study utilized several indices, including the Palmer pollution index (PPI), the index of pollution sensitivity (IPS), the trophic diatom index (TDI), the diatomic index (DI), and the Shannon and Weaver index (H). The results indicated that the ecological status of the water suggested the possibility of high organic pollution, ranging from oligo-mesotrophic to eutrophic status, and that the Lower Zab River had a moderate water quality. Thus, a continuous monitoring is mandatory to safeguard the aquatic niche. [ABSTRACT FROM AUTHOR]

Microplastics (MP) are one of the most significant pollutants in the marine environment. For the first time along the Alexandria coast from the eastern to the western side, Egypt, the study recorded MP in surface water and sediment (bed, and beach) from five stations covering two seasons in 2020. In addition, the study evaluated the potential ecological risk of MP using the polymer hazard index (PHI) and potential ecological risk index (PERI). Results indicated the fluctuation of MP abundance in water samples (1.3MP/ l). The wet season showed a higher abundance of MP. The MP content of beach sediment (446.9MP/ Kg) was more than that of the bed sediment (170.6MP/ Kg). Most MP particles were fiber-shaped, blue, and transparent, with sizes larger than 1mm. The chemical identification showed that polyamide and rayon were the most common polymers in most samples. The ecological risk indices indicate that Sidi Bishir area is classified as V level of risk, and the bed and beach sediments are subjected to extreme danger of MP pollution. The study recommends a deeper interest in the chemical analysis of polymers and standardizing the sampling and identification methods. Clear management strategies to control MP aquatic pollution with MP should be addressed. [ABSTRACT FROM AUTHOR]

Aims The purpose of this work was to study extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) in freshwaters, hospital effluents, and wastewaters during two sampling campaigns in 2021. Methods and results Water sampling was performed at 24 stations in the Ourthe watershed in Belgium. A total of 644 ESBL (n  = 642) and AmpC (n  = 2) E. coli strains were isolated. Disk-diffusion assays were performed following the EUCAST's recommendations. All strains were tested for the presence of bla CTX-M-1, bla CTX-M-2, and bla CTX-M-9 gene groups by PCR. Genes belonging to bla CTX-M-1 and bla CTX-M-9 groups were detected, respectively, in 73.6% and 14.9% of the strains. No bla CTX-M-2 group's gene was found. A subset of strains (n  = 40) was selected for whole genome sequencing. Escherichia coli serotype O18: H7 ST 1463 was predominant (n  = 14) in the sequenced strains and showed pathogenicity in the Galleria mellonella larvae model. β-lactamase genes identified were bla CTX-M (n  = 21), with bla CTX-M-15 mostly represented (n  = 15), as well as bla TEM (n  = 11), bla OXA (n  = 7), bla SHV (n  = 9), and carbapenemase (CP) genes were observed in several strains— bla KPC-3 (n  = 19), bla NDM-1 (n  = 1), bla VIM-1 (n  = 2), and bla OXA-244 (n  = 2)—even from freshwaters. Conclusions ESBL-EC are widely distributed in the aquatic environment in Belgium and contain a variety of ESBL and CP genes. [ABSTRACT FROM AUTHOR]

Feed residues and fish waste from floating net cage activities in Kedung Ombo Reservoir are the main issues in decreasing water quality, impacting the abundance of phytoplankton as primary producers. This study aimed to evaluate the relationship of nutrients and turbidity with phytoplankton abundance. This study used a field survey method with a purposive sampling technique. Samples were collected 3 times at intervals of 1 month at 3 different stations. Samples of water and phytoplankton were taken on the surface. Data analysis using multiple linear regression. The results showed that the nitrate concentration was 0.2–0.7 mg/L; phosphate 0.1–0.87 mg/L; and turbidity of 3.52–20.18 NTU. The phytoplankton abundance was 17,882–90,280 cells/L with a low diversity index (1.127–1.849), a high uniformity index (0.406–0.701), and a low dominance index (0.243–0.557). There is a strong correlation between nutrients, turbidity, and phytoplankton abundance, with a value of r = 0.800. The coefficient of determination (R2) = 0.640 indicates that phytoplankton abundance is influenced by nutrients and turbidity by 64%, while other factors influence the remaining 36%. [ABSTRACT FROM AUTHOR]

Collections of vertebrates and macroinvertebrates over two years from 26 lentic temporary water bodies each surveyed 1–4 times, in Ulster and Dutchess counties in the Hudson Valley of New York, USA, resulted in identifications of 166 species. These included species resident in temporary waters that have life stages resistant to drying and freezing, species that reproduce in temporary waters that need to mature before drying occurs, predatory species that visit temporary waters, and highly aquatic species that move overland to temporary waters. Temporary waters sampled had a range of hydroperiods from a few weeks to almost a year. Of the macroinvertebrates we identified to species, 75 were each collected in a single pool-survey (n = 62 pool-surveys). Pools with greater volume, more vegetation cover, lower pH and turbidity, and more sodium yielded greater species richness of macroinvertebrates, and species richness of certain taxa (eg Mollusca) were correlated with additional elements. We briefly discuss several unusual animal occurrences. [ABSTRACT FROM AUTHOR]

Faecal contamination of surface waters has the potential to spread not only pathogenic organisms but also antimicrobial resistant organisms. During the bathing season of 2021, weekly water samples, from six selected coastal bathing locations (n  = 93) and their freshwater tributaries (n  = 93), in Northern Ireland (UK), were examined for concentrations of faecal indicator bacteria Escherichia coli and intestinal enterococci. Microbial source tracking involved detection of genetic markers from the genus Bacteroides using PCR assays for the general AllBac marker, the human HF8 marker and the ruminant BacR marker for the detection of human, and ruminant sources of faecal contamination. The presence of beta-lactamase genes bla OXA-48, bla KPC, and bla NDM-1 was determined using PCR assays for the investigation of antimicrobial resistance genes that are responsible for lack of efficacy in major broad-spectrum antibiotics. The beta-lactamase gene bla OXA-48 was found in freshwater tributary samples at all six locations. bla OXA-48 was detected in 83% of samples that tested positive for the human marker and 69% of samples that tested positive for the ruminant marker over all six locations. This study suggests a risk of human exposure to antimicrobial resistant bacteria where bathing waters receive at least episodically substantial transfers from such tributaries. [ABSTRACT FROM AUTHOR]

Oil and gas occurrence characteristics and seepage characteristics of tight reservoirs are the key to production. CT technology can monitor displacement and advance seepage front in time In this chapter, NMR experiments of spontaneous imbibition and CT monitoring experiments of differential pressure displacement are carried out for dense conglomerate to clarify the law of two-phase seepage. The results show that in spontaneous imbibition, the fluid circulation in the pore of tight glutenite is high, and there is no micro-fracture The pore volume of clay minerals with high content increases when exposed to water, which improves the imbibition recovery ratio However, the highly heterogeneous gravel distribution increases the complexity of seepage path and thus enhances the imbibition recovery ratio. The strong heterogeneity of sandy conglomerate leads to the formation of preponderant passages in seepage In the early stage of displacement, the water flooding effect is poor and a large amount of water accumulates With the increase of displacement time, there is no obvious change in oil saturation at both ends of the middle part of a large number of water rock samples The oil saturation is lower at both ends and higher in the middle. [ABSTRACT FROM AUTHOR]

Water is a vital resource on the earth, serving as the foundation of life and playing a crucial role in our daily activities. Perfluorooctanoic acid (PFOA) is an organic compound, which poses a significant threat to the environment due to its persistence and bioaccumulation. PFOA exhibits various toxicities, including neurotoxicity, immunotoxicity, and carcinogenicity. It has been detected in worldwide of air and water samples, as it can easily move through different environmental media such as water, soil, and the atmosphere. The widespread distribution of PFOA in these media poses potential risks to both ecosystems and human health over the long term. Therefore, it is of utmost importance to develop a rapid detection method for accurately monitoring PFOA levels in water. In this study, the electrospray extraction ionization-tandem mass spectrometry (EESI-MS/MS) technique was utilized to directly and rapidly detect PFOA in tap water and river water. To achieve the highest ionization efficiency of PFOA in EESI-MS/MS across different water samples, the experimental parameters such as ion transfer tube temperature, spray voltage, electrospray solvent flow rate, and sample flow rate were optimized. The optimal conditions were temperature of 200 °C for the ion transfer tube, spray voltage of 2 kV, electrospray solvent flow rate of 4 µL/min, and sample flow rate of 6 µL/min. The experiments were conducted under negative ion mode with a mass scan range of m/z 50-500. Methanol solution was used as the electrospray solvent, and collision-induced dissociation (CID) was employed. The secondary characteristic fragment ion m/z 369 of m/z 413 for qualitative and quantitative analysis, enabling direct and rapid detection of PFOA in various water samples. The experimental results demonstrated good linearity of PFOA in the concentration range of 1-500 ng/L, with a linear correlation coefficient (R²) of 0.9976. The detection limit (LOD) of the proposed method is 0.57 ng/L, and the limit of quantification (LOQ) is 1.73 ng/L. The recovery rate ranges from 92.1% to 105.2%, with a relative standard deviation (RSD, n=6) of 1.89%-5.45%. In summary, this method has the advantages of high sensitivity, accuracy, and fast analysis speed, without the need of sample pretreatment. The established EESI-MS/MS method can be effectively applied for direct and rapid detection of PFOA in different water samples, showing promising prospects for monitoring environmental water pollutants. Moreover, it provides valuable references and technical means for the detection of other pollutants. [ABSTRACT FROM AUTHOR]

Thallium is an accumulative highly toxic metal, that can be present in environmental samples due to industrial pollution and is dangerous for living organisms. Thus, its determination at trace levels is necessary. The lab-in-syringe (LIS) is considered to be a simple, functional, and versatile, technique that combines operational concepts and flow and sequential injection analysis. In this study, a liquid-phase microextraction LIS system was developed as a front-end to flame atomic absorption spectrometry (FAAS) for the determination of thallium in water samples. The proposed approach is based on the formation of Tl(III) ammonium–pyrrolidine–dithiocarbamate complex followed by its extraction using di-isobutyl-ketone. These procedures take place within the syringe barrel of the LIS system. The limit of detection of the developed method was 2.1 µg L−1 with a linear range from 7.0 to 400 µg L−1. The relative standard deviation (RSD) was 3.9% (at 50.0 µg L−1 Tl(I)), demonstrating good precision. Moreover, good method accuracy was obtained since the relative recovery values were within the range of 93.4–101.2%. Finally, reliable method applicability and green merits were demonstrated using the blue applicability grade index and green analytical procedure index, respectively. The proposed method was used for the analysis of environmental water samples. [ABSTRACT FROM AUTHOR]

Cortisol is a key stress biomarker in humans and animals, including fishes. In aquafarming, stress monitoring using cortisol quantification can help to optimize aquaculture practices for welfare and productivity enhancement. However, most current methods for cortisol detection rely on invasive tissue sampling. In this work, we developed a gold nanoparticle (AuNP)-based cortisol sensor to address the demand of detecting picomolar ranges of cortisol from complex fish tank water matrices as a non-invasive alternative for more effective stress monitoring. We first identified a DNA aptamer with effective binding to cortisol and then conjugated the thiol-labelled aptamer to AuNPs together with a blocker molecule (CALNN) to form an Au-Apt-CALNN conjugate that is stable in fish tank water. The cortisol detection principle is based on magnesium chloride (MgCl2)-induced particle aggregation, where the cortisol-bound aptamer on the AuNPs folds into a tertiary structure and provides greater protection for Au-Apt-CALNN against MgCl2-induced aggregation due to steric stabilization. At an optimum MgCl2 concentration, the differential stability of particles with and without cortisol binding offers a limit of detection (LOD) of 100 pM for cortisol within a 35 min reaction. The aptasensor has been validated on recirculating aquaculture system (RAS) fish tank water samples by the HPLC method and was able to detect changes in water cortisol induced by two different stress paradigms. This on-site deployable and non-invasive sensor offers opportunities for more efficient and real-time fish stress monitoring for the optimization of aquaculture practices. [ABSTRACT FROM AUTHOR]