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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] more...

This study utilized cork powder as a green alternative for extractor phase using the parallel-disposable pipette extraction (Pa-DPX) method for the determination of pesticides such as atrazine, carbofuran, diuron, and simazine from aqueous environmental samples. The separation/detection was performed by HPLC–DAD. Optimization experimental conditions was achieved through univariate and multivariate designs, resulting in the following parameters: 15 mg of cork as extractor phase, 7 extraction cycles with 7.5% (m/v) NaCl in the sample, and 10 s were fixed per extraction cycle. For the desorption step, 300 µL of acetonitrile was used as solvent with 1 desorption cycle. The limit of detection and limit of quantification values were 7.5 µg L−1 and 25 µg L−1 for atrazine, carbofuran, and diuron, and 15.1 µg L−1 and 50 µg L−1 for simazine, respectively. Linear working range varied from 25 to 400 µg L−1 with coefficients of determination (R2) ≥ 0.983. The values of intraday precision varied from 4.9 to 18.1%, and those of interday precision varied from 21.3 to 32.2%. The accuracy of the method was determined through relative recoveries and the values ranged from 63.4 to 119.9%. The water environmental samples were collected at two different locations in Florianópolis, Santa Catarina, Brazil, and showed no detectable pesticides. The method presented here stands out due to the low consumption of sample and reagents, as well as the use of a renewable and biodegradable extraction phase (cork). The method is also a high-throughput alternative, due to the use of the Pa-DPX apparatus, which allows the preparation of up to five samples simultaneously. [ABSTRACT FROM AUTHOR] more...

Based on a Y-shaped wheel-mediated triple walker, an enzyme-free biosensor was reported for UO22+ detection. Due to the DNAzyme-driven mechanism, our walker was activated and produced a fluorescence signal for UO22+ assay. The sensor demonstrated ultra-sensitivity, good specificity and excellent accuracy, holding great promise for UO22+ sensing in complex water samples. [ABSTRACT FROM AUTHOR] more...

This article evaluates the criteria for diatom testing in forensic investigations, focusing on drowning cases. Diatoms, unicellular algae found in aquatic environments, are critical to the determination of drowning because water containing diatoms is inhaled during submersion. The primary objectives include defining the exact amount and type of tissue to be analyzed, expressed in terms of diatom concentration relative to tissue weight, and detailing the conditions under which water samples are collected to study the diatom flora at the site. In addition, the importance of accurately identifying diatom taxa and comparing them by unit weight is emphasized. To improve the reliability of diatom testing, the study discusses advanced methods such as microwave digestion, vacuum filtration, and automated scanning electron microscopy (MD-VF-Auto SEM), which offer higher sensitivity and specificity. The integration of DNA sequencing and deep learning techniques is explored, offering promising improvements in diatom detection and classification. These advances aim to reduce false positives and improve the accuracy of determining drowning as the cause of death. The article highlights the need for standardized protocols for diatom testing to ensure consistency and reliability. By incorporating new technologies and refining existing methods, the forensic application of diatom testing can be significantly improved, allowing for more accurate and reliable conclusions in drowning investigations. [ABSTRACT FROM AUTHOR] more...

• PAEs in water from the Three Gorges Reservoir area were investigated. • PAEs polluted the upper reaches of the Yangtze River more than the middle reaches. • Molecular weight and log K ow significantly affected the input and losses of PAEs. • DnNP may cause potential adverse effects for the aquatic ecology. Phthalic acid esters (PAEs) are a group of compounds widespread in the environment. To investigate the occurrence and accumulation characteristics of PAEs, surface water samples were collected from the Three Gorges Reservoir area, China. The total concentrations of 11 analyzed PAEs (∑ 11 PAEs) in the collected water samples ranging from 197.7 to 1,409.3 ng/L (mean ± IQR: 583.1 ± 308.4 ng/L). While DEHP was the most frequently detected PAE, DnBP and DnNP were the most predominant PAEs in the analyzed water samples with a mean contribution of 63.3% of the ∑ 11 PAEs. The concentrations of the ∑ 11 PAEs in the water samples from the upper reaches of the Yangtze River were significantly higher than those from the middle reaches. To better understand the transport and fate of the PAEs, seven detected PAEs were modeled by Quantitative Water Air Sediment Interaction (QWASI). The simulated and measured values were close for most PAEs, and differences are within one order of magnitude even for the worst one. For all simulated PAEs, water and particle inflow were main sources in the reservoir, whereas water outflow and degradation in water were important removal pathways. The contribution ratios of different sources/losses varied from PAEs, depending on their properties. The calculated risk quotients of DnNP in the Three Gorges Reservoir area whether based on monitoring or simulating results were all far exceeded the safety threshold value, implying the occurrence of this PAE compound may cause potential adverse effects for the aquatic ecology of the Three Gorges Reservoir area. [Display omitted] [ABSTRACT FROM AUTHOR] more...

Monitoring and predicting changes in water quality characteristics requires timely collection of water samples. Water sampling poses various challenges, including limited staff, difficulty in reaching water bodies such as lakes and wide rivers, and time limitations, particularly following natural calamities and emergencies. To address these challenges, a unique unmanned aerial vehicle (UAV)-assisted water sampling apparatus equipped with multiple containers to achieve autonomous multi-point water sampling at per flight was developed. By integrating a UAV with multi-container sampling devices, a single flight of the UAV can collect up to five samples with a maximum volume of 500 mL/sample. The system was assessed through many field experiments. The consistency and effectiveness of the sampling device were verified by comparing water samples from local lakes collected with those obtained through traditional collection techniques. The developed system has a greater level of speed and safety compared with manual water sampling from large surface waters such as lakes and hard-to-reach water bodies. [ABSTRACT FROM AUTHOR] more...

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Silver–NHC complexes have been recently reported for a wide variety of applications in the fields of catalysis and medicine. The key is the presence of a structurally versatile and tunable N-heterocyclic carbene (NHC) ligand on the Ag–NHC complex, which is useful to produce interesting properties. This work explores the potential of a silver-1,3,4,5-tetraaryl N-heterocyclic carbene (Ag–NHC) complex as a fluorophore for selective sensing of anions. Interestingly, the synthesised Ag–NHC complex was very selective for sulphide (S2−) ions even in the presence of other anions. The limit of detection (LOD) for the sensing was found to be 0.12 μM. The mechanism involved in the sensing process was studied by fluorescence and 1H-NMR studies. The potential of the Ag–NHC complex to sense S2− anions in real-world conditions was tested using water samples. [ABSTRACT FROM AUTHOR] more...

AbstractA new approach was developed for the speciation of hexavalent chromium ions in natural water samples relied on the complexation reaction with N, N-diethyl-p-phenylenediamine (DPD) and utilized a flatbed scanner as the detector. DPD form a stable complex which is distinguished by its pink color. In this study, several parameters were optimized, as well as the influence of interfering ions found in water samples. This procedure was successfully applied to the selective determination of hexavalent chromium in bottled, tap, and river water samples with a detection limit of 11.4 μg/L, recoveries between 92.3 and 108.0%, and reproducibility from 0.6 to 7.9%. [ABSTRACT FROM AUTHOR] more...

Here, we developed a novel, cost-effective fluorescence light-up biosensor for Pb2+ detection based on a label-free G-quadruplex combined with modified thioflavin T (ThT) derivatives. Among the various G-quadruplex sequences tested, only T2 exhibited fluorescence light-up properties upon interacting with the modified ThT derivatives in the presence of Pb2+. To enhance the Pb2+ sensing system, we also compared modified ThT derivatives, including the newly synthesized propyl-substituted ThT (ThT-P) and butyl-substituted ThT (ThT-B). Among the tested derivatives, ethyl-substituted ThT (ThT-E) exhibited the most significant fluorescence enhancement upon the addition of Pb2+. Our designed sensor demonstrated high selectivity and sensitivity for Pb2+, enabling practical applications, as validated through the successful detection of Pb2+ in spiked environmental water samples. We envision that our new strategy could be further developed into a versatile platform for the detection of a broad range of metal ions. [ABSTRACT FROM AUTHOR] more...

Flexible bis-benzimidazole-based V-shaped amphiphilic probes (1 and 2) that form a fluorescent nanoscopic assembly in aqueous media have been designed. The ion-binding properties of compound 1 are investigated in both polar protic (water) and aprotic (acetonitrile) solvents. In acetonitrile, the compound shows a distinct chromogenic response towards Hg2+ (LOD: 8.7 ppb) and F− ions (LOD: 13.2 ppb) owing to bathochromic shifts of the charge transfer band to different extents. The mechanistic investigation indicated that the Hg2+ ion coordinates with the probe molecule via the pyridyl nitrogen end (acceptor side), while the F− ion forms a hydrogen-bonded complex involving benzimidazole –NH groups (donor side). Though interaction with Hg2+ has been perceptible even in aqueous medium, no response is witnessed with the F− ion. Also, a significant change in the ion-binding properties was observed in the CH3CN medium when compound 2 with indole as the terminal residue was considered. The latter compound demonstrates sensitive yet not so specific interaction with Hg2+ ions and also no response towards anions despite having imidazole units. Furthermore, probe 1 has been utilized for rapid, on-site screening of real-life water samples using pre-coated, chemically modified paper strips. [ABSTRACT FROM AUTHOR] more...

Flexible bis-benzimidazole-based V-shaped amphiphilic probes (1 and 2) that form a fluorescent nanoscopic assembly in aqueous media have been designed. The ion-binding properties of compound 1 are investigated in both polar protic (water) and aprotic (acetonitrile) solvents. In acetonitrile, the compound shows a distinct chromogenic response towards Hg2+ (LOD: 8.7 ppb) and F− ions (LOD: 13.2 ppb) owing to bathochromic shifts of the charge transfer band to different extents. The mechanistic investigation indicated that the Hg2+ ion coordinates with the probe molecule via the pyridyl nitrogen end (acceptor side), while the F− ion forms a hydrogen-bonded complex involving benzimidazole –NH groups (donor side). Though interaction with Hg2+ has been perceptible even in aqueous medium, no response is witnessed with the F− ion. Also, a significant change in the ion-binding properties was observed in the CH3CN medium when compound 2 with indole as the terminal residue was considered. The latter compound demonstrates sensitive yet not so specific interaction with Hg2+ ions and also no response towards anions despite having imidazole units. Furthermore, probe 1 has been utilized for rapid, on-site screening of real-life water samples using pre-coated, chemically modified paper strips. [ABSTRACT FROM AUTHOR] more...

Novel heteroatom-doped carbon dots (APDP-CDs) were synthesized by hydrothermal treatment, and used for dichromate sensing. The average particle size of APDP-CDs was 3.91 nm. They showed absorption peaks at 207 and 290 nm, and fluorescence wavelength was 425 nm when excited at 370 nm. The quantum yield (QY) reached as high as 37.6%, when compared to quinine sulfate as the reference. APDP-CDs showed a linear detection range of 300 nM–1 mM, and the detection limit was found to be 19 nM. Furthermore, APDP-CDs exhibited excellent selectivity and anti-interference to dichromate in the case of different interfering species being present. The quenching process could be attributed to the surface electron transfer between the functional groups and Cr2O72− ions, as well as the inner filter effect. APDP-CDs have been used for actual water sample analysis with satisfactory results, which indicates that the carbon dot-based fluorescence sensor has potential application value. [ABSTRACT FROM AUTHOR] more...

Our research journey began with the successful synthesis and reporting of benzylidene amino aryl-pyridinone derivatives (4a–e) from corresponding pyranones. This process was conducted with meticulous attention to detail, ensuring the highest quality of results. These derivatives, treated with benzaldehyde and hydrazine hydrate under these controlled conditions, yielded an excellent yield. The benzylidene amino aryl-pyridinone, which contains electron-donor and acceptor groups, exhibited remarkable photophysical properties. We further evaluated the changes in the fluorescence properties of compound 4e in the presence of various cations. Our findings revealed compound 4e can be a highly sensitive and selective chemosensor for detecting Fe3+ and Hg2+ in DMSO solvent. The aggregated compound A-4e detected Fe3+ and Hg2+ with LODs of 1.03 × 10−7 M−1 and 1.71 × 10−7 M−1, which were lower than those in recent sensor reports. Presenting a novel approach to metal sensing will surely interest the scientific community. The application of compound 4e for the determination of Fe3+ and Hg2+ in spiked samples in different environmental water samples showed a satisfactory result with good recovery. [ABSTRACT FROM AUTHOR] more...

Arsenic is a widespread environmental contaminant that poses a significant threat to global health due to its toxicity and carcinogenicity. Given the high levels of arsenic found in the drinking water of western areas of Tehran, the objective of this study was to analyze levels of arsenic in multiple biological samples (blood, hair, and nails) collected from residents living in these areas. This cross-sectional study was conducted over three weeks in November 2022 in five villages. A total of 67 residents from these villages were included in the exposure group. Analysis of arsenic was carried out by using the Perkin Elmer Optima 8000 ICP-OES instrument coupled with the FIAS 100 flow injection module after sample digestion. The average concentration of arsenic in people's blood was 4.19 μg/l, which exceeds the standard limit of ATSDR (1 μg/l) by about 4 times. Additionally, 47.8% of blood samples exceeded the standard, while for nail and hair samples, the percentages were 22.4% and 13.4%, respectively. Water samples showed the highest percentage above the standard, with 67.2%. There is no significant relationship between arsenic levels in drinking water, hair and blood. However, a significant positive correlation was observed between the concentration of arsenic in drinking water and nail samples. The mean of hazard quotient (HQ) and carcinogenic risk (CR) indices of arsenic in drinking water suggest that the daily intake levels of the examined arsenic in the study area exceeded the acceptable thresholds ((HQ < 1) and (CR < 1 × 10−4)). Although this study demonstrated elevated arsenic exposure among the population in western Tehran, our findings showed no significant correlation between arsenic concentrations in drinking water and biological samples. Therefore, further research is required to identify other potential exposure pathways and develop targeted intervention strategies. Additionally, remediation measures to improve water quality remain essential in this rural area. [ABSTRACT FROM AUTHOR] more...

Uroglena sp. is a major contributor to the fishy odor in drinking water, with temperature being a key factor regulating its growth. However, no study has yet detailed its effect on Uroglena sp.'s growth. Uroglena sp. mainly blooms in spring when temperatures are lower, though similar lower temperatures are also present in autumn and winter. Therefore, the objectives of this study were to investigate the growth and decline behavior of Uroglena sp. under different temperatures and to assess the impact of microorganism composition in different samples on the growth of Uroglena sp. To achieve the objectives of this study, surface water samples collected in May (spring), September (autumn), and January (winter) were incubated under different temperatures. Findings revealed that Uroglena sp. exhibited higher and more prolonged growth at a low temperature of 5 °C. Within the temperature range of 10 to 20 °C, Uroglena sp. exhibited less vigorous growth and lysed more rapidly. No growth was observed at 30 °C. The limited growth of Uroglena sp. at higher temperatures is attributed to an increased abundance of bacteria and competition with other microalgae including Nitzschia sp., Sphaerocystis sp., Scenedesmus sp., Fragilaria sp., Attheya sp., Golenkinia sp., Melosira sp., and Dinobryon sp. This indicates that the coexistence of microalgae and bacteria plays a significant role in the growth of Uroglena sp. The maximum concentration of Uroglena sp. during incubation was higher for the water sample of May compared to the sample of September and January, which reached about 2500 colony/mL at 5 °C for the sample of May. The generally higher growth of Uroglena sp. with the sample of May suggests that less significant microalgae competition in the season could create more favorable conditions for the bloom of Uroglena sp. [ABSTRACT FROM AUTHOR] more...

Lead (Pb) is one of the most relevant contaminants due to its high toxicity, even at low concentrations. The growing need for research about real-time Pb analysis in the field has driven advancements in portable, sensitive, and automated analytical methodologies. These innovations are crucial for taking proactive measures against the impacts of Pb pollution on ecosystems and public health. Flow analysis techniques have proven to be very effective in automating procedures for isolating and preconcentrating Pb in surface water and biological samples. Such automation boosts sample throughput and reduces processing time and reagent consumption, aligning with the green chemistry principles by lowering costs and minimizing waste. This review covers 31 recent automated analytical methodologies employing flow analysis techniques such as FIA, SIA, MSFIA, and LOV, emphasizing the trend toward portability and miniaturization, which facilitates in-situ analysis. Additionally, this review examines the pretreatment methods and detection systems used, highlighting the analytical parameters of each technique. The methodologies discussed demonstrate the capability to process up to 55 samples per hour accurately. Limits of quantification as low as 0.014 µg L−1 are reported, enabling environmental monitoring that effectively detects Pb concentrations below the WHO and EPA drinking water reference values of 10 µg L−1 and 15 µg L−1, respectively. [ABSTRACT FROM AUTHOR] more...

Results change depending on the water quality evaluation methods used, and within good-quality water, many results still have parameters with concentrations exceeding the World Health Organization (WHO) desirable limits or national threshold values (TVs). Furthermore, there are few methods to classify the severity degree of contaminated water; most methods have problems in the parameter threshold boundary and in assigning weights. Aiming to solve the above problems, a water quality evaluation framework based on the single-indicator evaluation method (SIE), Weber–Fechner (W-F) law and Probabilistic Neural Network (PNN) is presented, named SIE&W-F&PNN. Forty-three confined water samples were collected for this research in Xi'an in September 2015. The SIE, water quality index (WQI) with three different weights (method weight, entropy weight and equal weight), comprehensive evaluation method (CEM) and SIE&W-F&PNN method were used, and the evaluation criteria for contaminated water were proposed based on the W-F law. The results of these methods were compared. The reasons for confined water pollution in Xi'an were analyzed. The results show that TC, NH4-N, NO2-N, β, As, Mn, F−, TH, Fe2+ and Turb were the contaminating parameters of the 43 confined water samples. In order, the results for the number or ratio of 'Poor' and even worse water samples by method are as follows: SIE-WHO (30, 69.77%) > SIE-GB = CEM (24, 55.81%) > WQI (entropy weight) (12, 27.91%) > WQI (method weight) (10, 23.26%) > WQI (equal weight) (9, 20.93%). These discrepancies highlight the influence of evaluation methods on the results. For this study, a water sample was classified as 'contaminated (bad) water' if any parameter exceeded either the national TV or the WHO's desirable limit, prioritizing drinking water safety. The SIE&W-F&PNN results show that there were 10 excellent water samples and 33 bad water samples (among which 4 water samples were rated as VL (very lightly polluted), 14 as L (lightly polluted), 14 as M (moderately polluted) and 1 as H (heavily polluted)). The SIE&W-F&PNN method ensures that no parameters in 'excellent' or 'good' water samples exceed the WHO's desirable limits or national TVs; can be used to classify the severity of contamination of contaminated water without assigning weights, avoiding the rate mutation near the threshold boundary; and can include any number of parameters and be applied to lakes, rivers, air, soil, etc. (i.e., it is not unique to groundwater). The primary causes of confined water pollution in Xi'an include historical pollution, contemporary anthropogenic activities, geological factors, excessive groundwater extraction, and the infiltration of contaminated surface and phreatic water. [ABSTRACT FROM AUTHOR] more...

Coastal and nearshore zones, severing as a connection between the land and the open ocean, are some of the most productive and complex ecosystems, where prokaryotes are abundant and highly diverse. However, the systematic study of the diversity of prokaryotes on a large-scale range in coastal and nearshore zones is limited due to scattered sampling sites, various sampling collection methods, and different data processing methods across various studies. Here, we provide a dataset of 16S rRNA gene sequences obtained from the surface water samples across the China Seas, including the Bohai Sea, the Yellow Sea, the East China Sea, and the South China Sea. The dataset comprises 1,194 samples collected through field sampling and literature search. A total of 30,308 operational taxonomic units clustered at 97% sequence identity were obtained. Sixty-five bacterial and nine archaeal phyla were identified. This dataset offers a basic understanding of prokaryotic diversity in the China Seas, also provides a foundation for in-depth investigations into prokaryotic distribution across different regions and their interactions in various environments. [ABSTRACT FROM AUTHOR] more...

Our research journey began with the successful synthesis and reporting of benzylidene amino aryl-pyridinone derivatives (4a–e) from corresponding pyranones. This process was conducted with meticulous attention to detail, ensuring the highest quality of results. These derivatives, treated with benzaldehyde and hydrazine hydrate under these controlled conditions, yielded an excellent yield. The benzylidene amino aryl-pyridinone, which contains electron-donor and acceptor groups, exhibited remarkable photophysical properties. We further evaluated the changes in the fluorescence properties of compound 4e in the presence of various cations. Our findings revealed compound 4e can be a highly sensitive and selective chemosensor for detecting Fe3+ and Hg2+ in DMSO solvent. The aggregated compound A-4e detected Fe3+ and Hg2+ with LODs of 1.03 × 10−7 M−1 and 1.71 × 10−7 M−1, which were lower than those in recent sensor reports. Presenting a novel approach to metal sensing will surely interest the scientific community. The application of compound 4e for the determination of Fe3+ and Hg2+ in spiked samples in different environmental water samples showed a satisfactory result with good recovery. [ABSTRACT FROM AUTHOR] more...

Marine fungi play a crucial role in carbon cycling and food webs by acting as saprophytes or parasites and shaping host communities. However, our knowledge of these fungi in the marine ecosystem remains limited. To address this gap, we conducted a study to investigate the diversity of planktonic fungal communities in the Red Sea, a warm and oligotrophic sea. We collected water samples from the photic layer at six sites along the Red Sea basin and analyzed the fungal community by targeting the 28S rRNA gene. Our results showed that Chytridiomycota dominated these communities, accounting for 85% of reads, followed by members of the divisions Basidiomycota (4.7%) and Cryptomycota (4.13%). Interestingly, we found that fungal communities did not exhibit significant changes with depth or chlorophyll concentration. However, they did vary with the latitudinal gradient in environmental conditions, which is characterized by high temperature (ranging from 22.3 to 27.0°C) and salinity (ranging from 38.0 to 40.4 PSU). Specifically, the proportions of Chytridomycetes and Neocallimastigomycetes (the two dominant classes of Chytridiomycota) were negatively correlated between themselves. Chytridomycetes exhibited a negative correlation with temperature (R2 = 0.60, p = 0.0028) and a positive correlation with salinity (R2 = 0.49, p = 0.010), being more abundant in the northern Red Sea. Conversely, Neocallimastigomycetes showed an increase in abundance with increasing temperature (R2 = 0.61, p = 0.0026) and a decrease with increasing salinity (R2 = 0.40, p = 0.026), making them more prevalent in the southern Red Sea. Overall, our study described a differential distribution of the most dominant fungal classes, with potential significance in their control of planktonic populations and consequent influence in the carbon cycle in the Red Sea ecosystem. These findings underscore the importance of further research to better understand the role of marine fungi in ecosystem functioning. [ABSTRACT FROM AUTHOR] more...

In this research, we fabricated a sensitive monoclonal antibody (mAb) 2C3 that targeted etomidate (ET) and metomidate (MT) to establish a lateral-flow immunoassay (LFIA) that incorporated fluorescent microsphere sensors, enabling both the qualitative and quantitative detection of ET and MT within 10 min. Analysis indicated that the visual colorimetric values for ET and MT in water samples were 0.3 μg kg−1, respectively, with quantitative detection ranges of 0.08 to 1.31 μg kg−1 and 0.08 to 2.21 μg kg−1, respectively. The visual colorimetric values for ET and MT in urine samples were 0.3 and 1 μg kg−1, respectively, with quantitative detection ranges of 0.12 to 3.13 μg kg−1 and 0.09 to 2.98, respectively, while for ET and MT in serum samples were 3 μg kg−1, with quantitative detection ranges of 0.15 to 21.2 μg kg−1 and 0.08 to 13.8 μg kg−1, respectively. Recovery tests and detection were conducted in water, urine and serum samples, validating the reliability of this method in clinical samples, consistent with those obtained from LC-MS/MS. Collectively, our novel LFIA provides a promising option for rapid on-site detection of ET and MT. [ABSTRACT FROM AUTHOR] more...

Introduction: The construction of nanomaterial-based ratiometric detection systems usually requires covalent modification, which undergoes reactive environments and may change the natural properties of supporting nanomaterials. Methods: In this study, dualemissive and fluorescein-decorated gold nanoclusters (F-Au NCs) through cyclodextrin-supported host–guest interaction (non-covalent modification) are explored as ratiometric Hg2+ nanoprobes through d10–d10-interactioncaused fluorescence quenching of Au NCs. Results and Discussion: The fluorescein decoration only provides a fluorescent internal reference but does not change the Hg2+-Au NCs affinity nature. Ratiometric and selective Hg2+ detection is achieved through the proposed F-Au NC probes with a limit of detection of 15 nM. The Hg2+ analysis in river water samples with small relative standard deviations validates the practical application of these probes. [ABSTRACT FROM AUTHOR] more...

Introduction: Wastewater treatment plants (WWTPs) and drinking-water treatment plants (DWTPs) are critical for public health due to the potential risks posed by microorganisms that may persist after treatment. The aim of this study was to detect the microbiome profiles of waters from both DWTPs and WWTPs under the Istanbul Water and Sewerage Administration (ISKI), identify the antimicrobial resistance profiles in all these facilities, and observe the differences in the microbiome between the inlet and outlet of different WWTPs. Methods: A total of 52 samples were examined, comprising 18 samples from DWTPs and 34 samples from WWTPs. All water samples underwent pre-isolation filtration. DNA isolation was conducted using filter material, followed by sequencing on a NovaSeq 6000 instrument. Kraken2 tools and R scripts were used for statistical analysis and data visualization. Results: The microbial metagenomic analysis identified 71 phyla, 113 classes, 217 orders, 480 families, and 1,282 genera across all samples. There were unclassified microbes (53.14% vs. 58.75%), Eukaryota (3.64% vs. 3.5%), Archaea (0.08% vs. 0.03%), bacteria (42% vs. 36.25%), and viruses (0.02% vs. 0.04%) in the raw water and ozonation unit outlet of DWTPs. The inlet and outlet of WWTPs showed unclassified microbes (52.68% vs. 59.62%), Eukaryota (0.6% vs. 1.72%), Archaea (0.26% vs. 0.15%), bacteria (46.43% vs. 38.43%), and viruses (0.05% vs. 0.04%). No statistically significant results were found in the analysis of raw waters collected from DWTPs and samples taken from the ozonation unit outlet—from the phylum level to the genus level (p > 0.05). The inlet and outlet points of WWTPs showed no statistically significant results from the phylum to species levels (p > 0.05). The most detected genera were Desulfobacter (4.82%) in preliminary WWTPs, Thauera (1.93%) in biological WWTPs, Pseudomonas (1.44%) in advanced biological WWTPs, Acidovorax (1.85%) in biological package WWTPs, and Pseudomonas (11.55%) in plant-based WWTPs. No antimicrobial resistance gene markers were detected in water samples from raw water inlets and ozonation unit outlets from DWTPs, membrane wastewater recovery plants, or ultraviolet (UV) recycling facilities. The ANT (3″), Erm , and Sul resistance gene markers were detected in all raw WWTPs samples. Discussion: There were no significant microbial risk differentiation between biological WWTPs and advanced biological WWTPs. The data could serve as preliminary information for future research. More extensive studies are needed, with multiple sample tracking in these facilities and their feeding basins. [ABSTRACT FROM AUTHOR] more...

Dehydration of the Philippine Sea Plate during subduction beneath the forearc region of southwest Japan releases fluids into the crust, potentially producing Arima-type fluids, which are characterized by anomalous hydrogen and oxygen isotopic compositions (δD and δ18O). Arima-type fluids have been identified in limited hot springs near active faults, such as the Arima and Takarazuka hot springs. The aim of our study is to understand why there have been limited reports of Arima-type fluids, despite the likelihood of their formation during slab dehydration. δ7Li data can be used to identify Arima-type fluids in samples with Cl– concentrations below 3400 mg/L, whereas δD and δ18O data have difficulty to detect them. In this study, we collected and analyzed samples from Okayama and Tottori Prefectures in southwest Japan, focusing on their chemical compositions and δ7Li and 87Sr/86Sr values. We found that the δ7Li and 87Sr/86Sr compositions of some of the water samples from Okayama Prefecture were similar to those of Arima-type fluids and that they are unlikely to be explained by other sources (e.g., local reactions with host rocks, residual hydrothermal/magmatic fluids, or seawater altered by rocks). Our results therefore suggest there may be a more extensive distribution of Arima-type fluids in the forearc region of southwest Japan than has been previously reported. [ABSTRACT FROM AUTHOR] more...

Radon (222Rn), among all natural radiation sources, is considered the most hazardous to human health. This study evaluated the 222Rn concentration and radiological risk in the surface water and groundwater in Dareta Village. The water samples were randomly collected, and 222Rn was measured using a DURRIDGE-RAD7 analyzer. The mean 222Rn concentration was in the range of 2.64 ± 0.10–12.30 ± 3.20 Bq/l, and the mean of the total annual effective dose was 12.54–82.02 µSv/y. Based on these findings, it can be concluded that the 222Rn concentrations were safe, except for ZGW-01 and ZGW-02. However, it is recommended that water samples be treated before consumption. [ABSTRACT FROM AUTHOR] more...

A simple, fast, and cost-effective colorimetric nitrite (NO2−) sensor based on ZIF-67-derived Co3O4 nanocomposite (ZCo-2 NC) structure has been developed. The prepared colorimetric sensor (ZCo-2 NC) was employed to sensitively detect NO2− in drinking water system by the exhibition of promising peroxidase-mimicking nanozyme-like features. The sensor manifest well-determined sensing response with excellent linear and wide range of NO2− sensitivity (0.001–0.810 μM). The lower detection-limit (LOD) and lower quantification-limit (LOQ) were 0.14 ± 0.05 nM and 0.72 ± 0.05 nM, respectively, which is far below the US-EPA limit (21.7 μM). Further, the sensor also provides strong selectivity response to NO2−, better reversibility (12 cycles), and commendable stability of 10 weeks. In addition, it also perceived astonishing practicality towards NO2− in real water samples. Thus, this study opens a new pathway for the sensitive detection of NO2− in drinking water for future endeavor. [ABSTRACT FROM AUTHOR] more...

A novel Ru-Fe3O4 nanozyme with enhanced peroxidase-like (POD-like) activity was synthesized through a hydrothermal method. Ru-Fe3O4 nanozyme was effectively utilized for the detection of thiophanate-methyl (TM) using a colorimetric technique. The POD-like activity of Ru-Fe3O4 was found to be superior compared to Fe3O4, Rh-Fe3O4, and Pd-Fe3O4. Ru-Fe3O4 provided excellent POD-like activity with Michaelis constants of 0.00645 mM and 0.66714 mM for substrates of 3,3',5,5'-tetramethylbenzidine and H2O2, respectively. The density functional theory calculation showed that Ru-Fe3O4 had better H2O2 decomposition reactivity compared to Fe3O4. Compared with Fe3O4, the adsorbed H2O2 molecules underwent decomposition more readily on the Ru-Fe3O4 catalytic surface facilitating the occurrence of the H2O2 catalytic reaction, further suggesting the excellent POD-like activity of Ru-Fe3O4. The coordination and electrostatic interactions of Ru-Fe3O4 and TM promoted their binding, contributing to TM covering Ru-Fe3O4 catalytic site and inhibiting the POD-like activity of Ru-Fe3O4. As a result, the sensitive and selective detection of TM using Ru-Fe3O4 by a colorimetric method was achieved. The Ru-Fe3O4 nanozyme displayed a good linear correlation, with a linear detection range and a detection limit of 0.1–100 and 0.03 μg/mL, respectively. The Ru-Fe3O4 nanozyme was used for the determination of TM in soil and water samples with success. [ABSTRACT FROM AUTHOR] more...

Fe, Ni, and Cu doped ceria nanoparticles (CeNPs) were prepared with a simple and one-pot hydrothermal synthesis method. We investigated the chemiluminescence (CL) interaction between these NPs and rhodamine B (Rh B) and found that the highest CL intensity was related to the Rh B- Cu doped CeNPs. We assigned that to the higher catalytic property of Cu doped NPs compared to the others. Cu doped CeNPs have been applied for the first time as a catalyst in chemiluminescence reactions. Rh B- Cu doped CeNPs reaction was introduced as a novel CL system, and its mechanism was studied. Considering the sensitivity, simplicity, portability, and rapidness of the CL methods, we applied the introduced reaction to the development of a CL sensor for nitrite monitoring. In the presence of nitrite, the CL intensity of the system decreased, and there was a linear relationship between the CL intensity and nitrite concentration in the range 0.5–100 µM. Based on this fact, a sensitive and selective CL sensor with the detection limit of 0.2 µM was established for nitrite detection in various food and water samples. [ABSTRACT FROM AUTHOR] more...

This research aimed to develop a method for the speciation analysis of arsenic species, including As(III) and As(V) in environmental samples. Cotton fibres and thiol-ligands, including ammonium pyrrolidine dithiocarbamate (APDC), L-cysteine, and diethyldithiocarbamic acid (DDTC), were used as a simple solid phase extraction (SPE) followed by arsenic determination using inductively coupled plasma optical emission spectrometry (ICP-OES). The separation parameters were thoroughly investigated, including pH, thiol-ligand concentration, cotton fibre amount, type of eluents, and flow rate. It was found that As(III) could be efficiently separated from As(V) by using a column containing 0.5 g cotton fibres and 0.1% APDC under pH 2. As(III) was then eluted using 5 mL of mixed solvents of 4 M HNO3, 4 M HCl, and 0.5 M H2O2 (1:1:1 v/v). The method was then used to perform a speciation analysis of arsenic in model solutions with As(III) and As(V) concentrations ranging from 10–1000 μg/L. The results showed good recoveries of both arsenic species at 80–120% with a satisfactory percentage relative standard deviation (%RSD). The developed method was subsequently applied for arsenic speciation analysis in the environmental samples, including natural and wastewater samples. [ABSTRACT FROM AUTHOR] more...

Solution cathode glow discharge atomic emission spectrometry (SCGD-AES) using wide-bandpass (10-nm) interference filters (IF) as a spectral discrimination device was used for the determination of thallium (Tl) in surface water. The use of wide-bandpass interference filters greatly reduces the cost of traditional detection instruments. The influence of solution flow rate, discharge current and pH on the detection limit was characterized. Moreover, matrix effect experiments were performed to study the effect of different concentrations of Na+, K+, Ca2+, and Mg2+ on the Tl signal intensity. Using a solution flow rate of 2.8 mL/min, a discharge current of 50 mA, and pH of 1.0 with HNO3 as the supporting electrolyte, SCGD coupled with an interference filter provided a detection limit of 7.76 μg/L for Tl in water samples, comparable to traditional SCGD-AES. Furthermore, the spiked recovery rate of Tl is quantitative in real water samples and comparable to the performance of inductive coupled plasma – optical emission spectrometry (ICP-OES). [ABSTRACT FROM AUTHOR] more...

A novel dispersive magnetic micro-solid-phase extraction (DM-µ-SPE) method based on the magnetic NiFe2O4 polyamidoamine dendrimers modified with deep eutectic solvent sorbent has been developed for the extraction of naproxen and nabumetone. The extracted analytes were quantified by a high-performance liquid chromatographic (HPLC) method with UV detection at 280 nm. The linearity was in the range of 1–400 µg L−1 for naproxen and 3–400 µg L−1 for nabumetone. The developed DM-µ-SPE/HPLC–UV method has been characterized by excellent intra- and inter-day repeatability of 2.3, 3.3, and 2.5, 4.0%, respectively, for naproxen and nabumetone at the concentration level of 70.0 µg L−1 (n = 5). Enhancement factors of 157.7 and 151.8 and limit of detections of 0.15 µg L−1 and 0.26 µg L−1 for naproxen and nabumetone were achieved, respectively. The sorption isotherm study illustrated that the experimental data of NAP fitted better to the Langmuir isotherm with a maximum monolayer sorption capacity of 76.92 mg g−1, while the NAB data fitted to the Temkin isotherm model. The method was successfully applied to the determination of non-steroidal anti-inflammatory drug analytes in water and milk samples. [ABSTRACT FROM AUTHOR] more...

The cement-treated dredged mud mixture is suitable for backfill in earthwork projects because of its high water content and flowability. Incorporating geogrid can enhance the mixture's tensile strength. Constructing with cement-treated mud at greater heights generates curing stress, affecting the interface with geogrid. Pullout tests were performed to analyze the impact of curing stress, water content, and cement content on the interface performance. Results showed similar pullout force-displacement curves regardless of curing stress, indicating strain-softening behavior. Higher water content resulted in decreased pullout forces, while higher cement content led to increased pullout forces. Samples under curing stress exhibited increased peak pullout forces ranging from 2% to 70% compared to samples without curing stress. The rate of increase in pullout force because of curing stress decreased with higher water or cement contents. Curing stress influenced the interface friction angle in specimens with water contents 1.5 and 2 times the liquid limit. It significantly affected the interface cohesion in samples with water contents 2.5 times the liquid limit. Samples subjected to curing stress demonstrated a higher apparent friction coefficient, with an average increase ranging from 4% to 43%, which decreased with higher water content and lower cement content, regardless of curing stress. [ABSTRACT FROM AUTHOR] more...

The vertical distribution and potential variability of Per- and Polyfluoroalkyl substances (PFAS) in the water column of lacustrine systems is important to know for sampling and monitoring purposes, but could also relate to details of their fate, transport, and distribution. In this study, the water column of a eutrophic freshwater lake (Lake Monona, Madison, WI, USA) was sampled vertically for PFAS during summer stratification at several depths (surface microlayer to 1 m from the bottom) and then monitored at four dates and three depths the following year to assess seasonality. PFAS concentration did not exhibit vertical stratification or large variability in the water column. However, seasonal variation in PFAS concentration was detected, as well as an increase in PFAS concentration related to drought conditions. This study suggests that a surface water grab sample may be a sufficient representative of the water column for the basic monitoring of PFAS. But a single sample during the year may not provide a complete understanding of the lake, and multiple samples should be taken to capture and understand important seasonal events. [ABSTRACT FROM AUTHOR] more...

Coastal lagoons have undergone changes due to anthropogenic activities, the presence of wastewater discharges, and unsustainable practices that alter water quality, favoring the presence of pathogenic microorganisms such as Vibrio. This study identified the presence of the genes for zinc metalloproteinase (HA) Vibrio sp. and choleric toxin (ctx) Vibrio cholerae, associated with the sources of contamination in the Mandinga Coastal Lagoon (MCL). During 2017, samplings were carried out in which sources of contamination associated with anthropogenic activities were identified. At the same time, water samples were collected from which DNA was extracted and the presence/absence of the HA and ctx genes was detected with a PCR analysis. The HA gene was identified in the three seasons of the year, while the ctx gene was only present in the dry and rainy seasons. The prevalence of both genes in the study area was independent of the presence of the pollution sources identified in the area. The absence of the ctx gene during the northern season is associated with the variability of the physicochemical parameters typical of the season. [ABSTRACT FROM AUTHOR] more...

In this study, we experimentally investigate the production and characterization of CaCO3 particles through the carbonation process of Ca(OH)2 and evaluate their potential application in removing organic matter. The CaCO3 particles were characterized using BET, SEM-EDX, FT-IR, particle size, and XRD techniques. Adsorption of organic matter was studied using synthetic solutions and samples from two surface water sources. Experiments were conducted at room temperature with adsorbent dosages ranging from 1.3 to 21.5 g/L, initial dissolved organic carbon concentrations between 2.5 and 20 mg/L (initial loading: 0.1–14.6 mgDOC/gCaCO3), and a contact time of at least 5 minutes. We observed a removal efficiency of 70–80% for DOC and 90–95% for UV254 at a low concentration of organic matter (humic acids, 2.5 mgDOC/L). At a concentration of 5.0 mg DOC/L, we achieved (i) 70–90% DOC removal for humic acid, (ii) 50–65% DOC removal for one surface water sample with SUVA254 of 2.4 L/mg·m, and (iii) 20–35% DOC removal for another surface water sample with SUVA254 of 4.3 L/mg·m. Furthermore, we investigated the performance of the prepared particles in repeated usage for organics removal. In conclusion, our findings propose areas for future research including optimizing particle cycling within the reaction environment, exploring particle utilization in reactors such as an up-flow particle bed, and assessing potential applications in a membrane contactor. The environmentally friendly and non-toxic nature of CaCO3 particles emphasizes their significance in future research and applications. [ABSTRACT FROM AUTHOR] more...

Due to incessant contamination of the groundwater system near the dumpsite in southwestern Nigeria Basement Complex, this study seeks to evaluate the impact of the Odogbo dumpsite on the local groundwater system by integrating geophysical and geochemical methodologies. Aeromagnetic data covering the study area was acquired, processed, and enhanced to delineate basement features that could potentially be passing plumes to the groundwater system. Concurrently, geoelectric methods using 2-D dipole–dipole imaging and vertical electrical sounding (VES) were utilized to characterize the vulnerability indices of the lithologies underlying the dumpsite. The resistivity data was collected with the UltraminiRES resistivity meter. Vulnerability assessment of the regolith was conducted through longitudinal conductance rating. Water samples from the vicinity of the dumpsite were analyzed using a spectra AA220 atomic absorption spectrophotometer (AAS). The results of magnetic derivatives and analytical signals filters revealed that the Odogbo dumpsite is directly situated atop lineaments trending mainly in an NE-SW direction. The 2-D resistivity model depicted the extent of the leachate plume percolation, characterized by resistivity values below 20 Ωm. The curve types identified from VES results were A, H, HK, and KQ while the geoelectric layers were identified as topsoil, weathered layer, lateritic layer, and fresh/fracture basement. The protective capacity varied across the area, from 0.02 to 0.473 mhos, signifying weak to moderate protective capacity of the overlying layer. Most elemental parameters tested fell below the World Health Organization (WHO) permissible values and some were within WHO standards except iron. All the water sampled were rated poor to unsuitable as their water quality index (WQI) ranged between 232.81357 and 1520.88776 due to high elemental iron content which could be from other sources. The study area is safe from contamination for now but there is a high tendency that the area may be contaminated in future; hence, the need to monitor the region periodically is highly recommended. [ABSTRACT FROM AUTHOR] more...

The topic of water reuse is becoming increasingly important. It might be possible to use the well-known antibacterial effect of atmospheric pressure plasma due to its special mixture of reactive species, UV, and electromagnetic fields in a scaled-up, industrially interesting area to remove bacteria from wastewater, and thus, make it usable again. To review this question, water volumes of 5 L and of different qualities (turbidity and different degrees of hardness) were treated with a commercially available plasma system. The change in water-specific values such as pH, EC, ORP, nitrate, and nitrite content was determined. To test the antibacterial effect, both direct and indirect treatment of the test germ Pseudomonas aeruginosa was conducted. In the first case, the inoculated water samples were plasma-treated, while in the second case, the water samples were treated before inoculation with the germ. The viable bacteria were counted via the spread plate method. The best reduction rate of at least 6 log levels was achieved when inoculated deionized water samples were treated directly with plasma. A significant reduction in viability was also observed in directly treated clear tap water samples, whereby the different degrees of hardness did not influence the effectiveness of the plasma. The bacterial load remained almost unchanged when reused water samples from a car wash were treated. Based on the results, a possible application in a car wash was discussed including a cost estimation and possible limitations. [ABSTRACT FROM AUTHOR] more...

The polymerase chain reaction (PCR) is a molecular biology tool with diverse applications in the aquatic sciences. Classical PCR is a nonquantitative method that can be used to detect target DNA sequences that are characteristic of particular microbial taxa but cannot determine their concentrations in water samples. Various quantitative forms of PCR have been developed to remove this limitation. Of these, the two that currently are used most widely are real-time quantitative PCR (qPCR) and droplet digital PCR (ddPCR). Several outlines of the mathematical and statistical basis of these methods for estimating target sequence concentrations are available in the literature, but we are aware of no thorough and rigorous derivation of the theoretical underpinnings of either. The purpose of this review is to provide such derivations, and to identify and compare the main strengths and weaknesses of the two methods. We find that both estimation methods are sound, provided careful attention is paid to specific details that differ between the two. With qPCR, it is especially important to reduce any significant PCR inhibition by sample constituents and to properly fit the standard curve to heteroskedastic calibration data. With ddPCR, it is important to ensure that the value of the mean droplet volume used in calculating concentrations is correct for the particular combination of droplet generator and master mix used. The advantages of qPCR include lower instrument and per-sample costs, a shorter turnaround time for obtaining results, a higher upper limit of quantification, and a wider dynamic range. The advantages of ddPCR include freedom from dependence on a standard curve, an inherently lower sensitivity to PCR inhibitors, a lower limit of quantification, a simpler theoretical basis, and simpler data analysis. We suggest qPCR often will be preferable in laboratory studies where investigators have significant control over the range of target sequence concentrations in samples, concentrations are sufficiently high so proper calibration does not require standards with concentrations low enough to exhibit exaggerated variability in the threshold cycle, and no significant inhibition is present, or more generally, in studies where funding levels do not permit the higher cost of instrumentation and supplies required by ddPCR or where the shorter turnaround time for qPCR is essential. If sufficient funds are available, ddPCR often will be preferable when the ability to quantify low concentrations is important, especially if inhibitors are likely to be present at concentrations that are problematic for qPCR. [ABSTRACT FROM AUTHOR] more...

Multi-drug-resistant bacteria pose a significant global threat to public health, particularly among patients with critical nosocomial infection. Notably, the genera Klebsiella and Raoultella are of concern due to their association with human infections and the transfer of antibiotic-resistance genes. Phage therapy has recently garnered attention as a novel approach to treating these infections. However, the efficacy of this method relies on phages with a broad host range. In this study, the phage K14-2 with a wide host range was isolated from a river water sample using Klebsiella pneumoniae as the host. The biological properties of the phage were characterized by assessing its multiplicity of infection, killing curve, one-step growth curve, and stability across different pH levels and temperatures. The morphological analysis revealed that the phage closely resembled myovirus. The host range included 15 strains across 6 species from Klebsiella , Raoultella , and Escherichia genera. The genome of K14-2 was found to be double-stranded DNA, comprising 175,759 base pairs with a GC content of 41.8%. Genome annotation revealed 280 protein-coding genes, of which 96 had assigned functions. The phage with the highest genomic similarity to K14-2 was vB_KpM-Milk. Phylogenetic trees constructed based on the major capsid protein revealed that the phage belonged to the genus Slopekvirus of the Straboviridae family. Given these characteristics, the discovery of the novel phage K14-2, with its broad host range, holds potential for enhancing the effectiveness of phage therapy in future studies. [ABSTRACT FROM AUTHOR] more...

The controlled growth of oriented hexagonal ZnO nanosheets (ZnONSs) on a nitinol (NiTi) fibre substrate without a seeding layer was presented by using ZnCl2 as a precursor and KCl as a supporting electrolyte and a capping agent. The effect of the electrolytic composition and electrodeposition parameters on the morphology of ZnONSs was investigated. After annealing, novel porous ZnONSs (P-ZnONSs) were obtained and the overall morphology of oriented hexagonal ZnONSs was well maintained. The P-ZnONS coated NiTi (NiTi@P-ZnONS) fibre was used for solid-phase microextraction (SPME) coupled to HPLC-UV and showed good adsorption selectivity for polycyclic aromatic hydrocarbons (PAHs). As compared with that of the ZnONS coated NiTi (NiTi@ZnONS) fibre, the adsorption efficiency of the NiTi@P-ZnONS fiber was further improved. Moreover, the NiTi@P-ZnONS fibre showed superior adsorption capability for PAHs compared to typical commercially available 7-μm polydimethylsiloxane and 85-μm polyacrylate fibres. After the optimisation of SPME conditions with the NiTi@P-ZnONS fibre, good linearity was obtained in the range of 0.03–200 μg L−1 (R2 ≥ 0.9980) with low limits of detection (0.011–0.115 μg L−1) and limits of quantification (0.037–0.383 μg L−1). The intra-day and inter-day relative standard deviations (RSDs) of the proposed method with a single fibre ranged from 3.02% to 4.75% and 3.20% to 5.83%, respectively. Meanwhile, the proposed method was used for the selective preconcentration and determination of trace target PAHs in real water samples. Relative recoveries varied from 82.8% to 105% with RSDs from 3.34% to 8.58%. Additionally, this fibre presented good solvent resistance to perform a whole analytical process. [ABSTRACT FROM AUTHOR] more...

In the present study, dispersive solid phase extraction – hydride generation integrated with micro–sampling gas–liquid separator – flame atomic absorption spectrometry was proposed to determine lead in lake water samples taken in the Horseshoe Island, Antarctica. In scope of this study, microwave assisted NiFe2O4 nanoparticles were synthesized, and the characterization of nanoparticles were carried out by FT-IR, XRD and SEM. All influential parameters of dispersive solid phase extraction and hydride generation were optimized to enhance signal intensity belonging to the analyte. System analytical performance studies were performed, and limit of detection and limit of quantitation were calculated as 2.16 µg kg–1 and 7.19 µg kg–1, respectively. Recovery studies were conducted to the spiked lake water samples and two different calibration strategies were applied. Percent recovery results were calculated between 102.0 and 169.5% by external calibration strategy while matrix matching calibration strategy provided recovery results in the range of 78.8–142.9%. [ABSTRACT FROM AUTHOR] more...

Quantitative polymerase chain reaction (qPCR) offers a rapid, automated, and potentially on-site method for quantifying L. pneumophila in building potable water systems, complementing and potentially replacing traditional culture-based techniques. However, its application in assessing human health risks is complicated by a tendency to overestimate risks due to the detection of genomic copies unassociated with viable, infectious bacteria. This study examines the relationship between L. pneumophila measurements via qPCR and culture-based methods, aiming to establish qPCR-to-culture concentration ratios needed to inform associated health risks. Eligible studies collected quantitative data on L. pneumophila concentrations using molecular and culture-based methods within paired water samples. We developed a Poisson lognormal ratio model and a random-effects meta-analysis model to analyze variations in qPCR-to-culture ratios within and across sites. Of the 17 studies in the systematic review, seven, including 23 site-specific data sets, were used for meta-analysis. Our findings indicate these ratios typically vary from 1:1 to 100:1, with ratios close to 1:1 predicted at all sites. Consequently, adopting a default 1:1 conversion factor appears necessary as a cautious approach to convert qPCR concentrations to culturable concentrations for use in health risk models, such as quantitative microbial risk assessment (QMRA). Where this approach may be too conservative, viability-qPCR could improve the accuracy of qPCR-based QMRA. Standardizing qPCR and culture-based methods and reporting site-specific environmental factors affecting L. pneumophila culturability would improve understanding of the relationship between the two methods. The ratio model introduced here advances beyond simple correlation analyses, facilitating investigations of temporal and spatial heterogeneities in the relationship. This analysis is a step forward in the integration of QMRA and molecular biology, and the framework demonstrated for L. pneumophila is applicable to other pathogens monitored in the environment. [ABSTRACT FROM AUTHOR] more...

The disinfection of drinking water, while critical for public health, leads to the formation of disinfection byproducts (DBPs). Toxicological and epidemiological studies have demonstrated that exposure to disinfected water samples may pose adverse effects on human health. Recent research highlights the potential greater toxicity contribution of DBP fractions with high molecular weight (MW) (with more than two carbon atoms) compared to regulated low MW DBPs, emphasizing the need for advanced analytical techniques to identify and characterize these fractions. In this review, we summarize different analytical techniques for indirectly assessing DBP precursors and directly analyzing DBPs, discussing their advantages and limitations. Additionally, since identifying DBP toxicity agents in complex water mixtures is crucial for further optimizing water disinfection and controlling DBP formation, key DBP identification methods based on both chemical and bioassay metrics are also included and discussed. Finally, we highlight three important aspects for the future development of analytical methods to enhance the understanding of high MW DBP formation. [ABSTRACT FROM AUTHOR] more...

AbstractAn acid-base reaction-based dispersive solid-phase extraction approach was developed for extracting favipiravir before its determination using an electrochemical sensor. The analyte was extracted from the samples using folic acid as an adsorbent. Cu@MoO2 nanoparticles were synthesized by chemically reducing CuMoO4 with NaBH4 and nitrogen-rich carbon (N-C) was prepared from safranine-O dyes. The characterized Cu@MoO2/N-C composites were used as an electrode modifier. The linear range and detection limit of the favipiravir were found to be 0.01-10 µM and 0.7 nM, respectively. The developed system was applied to determine favipiravir in urine and water samples, with recoveries of 101-102% and 97-99%, respectively. [ABSTRACT FROM AUTHOR] more...

This article reports on the long-term use, solid bismuth microelectrode arrays for the first time. The presented working microelectrode is characterized by particular advantages compared to bismuth film electrodes and solid single bismuth microelectrodes; these advantages include environmentally friendly properties and the amplification of recorded currents, which are subsequently more resistant to interference. The proposed solid bismuth microelectrode array was applied to develop an adsorptive stripping voltammetric procedure for Sunset Yellow determination. The main experimental parameters were optimized. The calibration graph was linear from 5 × 10−9 to 1 × 10−7 mol L−1 (time of accumulation, 60 s). The detection limit was equal to 1.7 × 10−9 mol L−1. The relative standard deviation for a concentration of Sunset Yellow of 2 × 10−8 mol L−1 was 4.1% (n = 7). Potential interference effects were examined. The presented analytical procedure was applied for the determination of Sunset Yellow in isotonic beverages and the results were confirmed by HPLC as a comparative method. The correctness of the presented procedure was also confirmed by satisfactory recovery values obtained during the analysis of spiked environmental water samples. [ABSTRACT FROM AUTHOR] more...