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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]

AbstractAcrylamide, a probable human carcinogen present in heat-processed foods and environmental contaminants, requires sample extraction and preconcentration before chromatographic analysis. The method developed in this study employed derivatization with xanthydrol and dispersive liquid–liquid microextraction utilizing low-density anisole. Durian or potato chips were combined with deionized water, defatted with hexane, and subjected to precipitation of soluble carbohydrates and proteins using clarification reagents. Water samples were filtered through a membrane filter. Acrylamide was derivatized by introducing an acidic methanolic solution of xanthydrol at 50 °C. The derivatized acrylamide was extracted with 70 µL of anisole and vortexed, with the methanol from the xanthydrol solution serving as the disperser solvent. The anisole layer was analyzed using gas chromatography with both flame ionization and mass spectrometric detection. Linear calibration plots exhibited coefficients of determination >0.9997. The precision was measured at <10% RSD, and recoveries ranged from 84% to 107%. The quantitation limit varied from 2 to 10 µg kg−1 for processed chips and from 0.05 to 0.10 µg L−1 for water samples. Acrylamide was detected in all processed chip samples, with some concentrations exceeding the benchmark value of 750 μg kg−1. However, no acrylamide was identified in any of the water samples. [ABSTRACT FROM AUTHOR]

Quantifying the relative influence of factors and processes controlling riverine ecosystem function is essential to predicting future conditions under global change. Dissolved organic matter (DOM) is a fundamental component of riverine ecosystems that fuels microbial food webs, influences nutrient and light availability, and represents a significant carbon flux globally. The heterogeneous nature of DOM molecular composition and its propensity for interaction (i.e., functional diversity) can characterize riverine ecosystem function across spatiotemporal scales. To investigate fundamental drivers of DOM diversity, we collected seasonal water samples from 42 nested locations within five watersheds spanning multiple watershed sizes (~ 5 to 30,000 km2) across the United States. Patterns in DOM molecular richness, aromaticity, relative abundance of N-containing formulas, and putative biochemical transformations derived from high-resolution mass spectrometry were assessed across gradients of explanatory variables associated with watershed characteristics (e.g., watershed area, water residence time, land cover). We found that putative biochemical transformations were more strongly related to explanatory variables across watersheds than common bulk DOM parameters and that watershed area, surface water residence time and derived Damköhler numbers representing DOM reactivity timescales were strong predictors of DOM diversity. The data also indicate that catchment-specific land cover factors can significantly influence DOM diversity in diverging directions. Overall, the results highlight the importance of considering water residence time and land cover when interpreting longitudinal patterns in DOM chemistry and the continued challenge of identifying generalizable drivers that are transferable across watershed and regional scales for application in Earth system models. This work also introduces a Findable Accessible Interoperable Reusable (FAIR) dataset (> 300 samples) to the community for future syntheses. [ABSTRACT FROM AUTHOR]

ABSTRACT A novel salamo‐Co (II) coordination polymer probe CP was synthesized firstly, and its crystal structure, [Co3(L)2(PTA)(H2O)2]n·4nDMF, was determined by X‐ray diffraction analysis. The probe has a rare aggregation‐induced luminescence enhancement (AIEE) effect. When applied to amino acid detection, it was found to have a high selective recognition of tyrosine. With the increase of tyrosine, the fluorescent strength of the probe was enhanced in a short period of time. In addition, the binding ratio of probe to Tyr was determined by fluorescence titration experiment, and the detection limit LOD of probe CP for Tyr was calculated to be 2.57 × 10−9 M, and the binding constant Ka was 2.96 × 105 M−1. According to UV absorption spectrum, FT‐IR spectra, ESI mass spectrometry, and DFT calculation, it was speculated that Tyr can bind to the probe after adding Tyr into the probe solution, triggering FRET and ICT effects, resulting in increased fluorescence intensity and blue shift, and finally achieving the specific recognition of tyrosine by probe CP. Finally, the practical application of probe CP was studied. Through strip test and real water sample test, it was found that the probe can be used for qualitative and quantitative analysis of tyrosine. [ABSTRACT FROM AUTHOR]

The extent of the stable nitrogen (N) isotope ratio (δ15N) of mangrove leaves reflects the anthropogenic N accumulation potential of mangroves. Therefore, the present study was designed to investigate the N accumulation potential of Okinawa mangroves in Japan using three ecological indicators from four mangrove watersheds. The dissolved inorganic nitrogen (DIN) concentration in mangrove creeks, the leaf δ15N and the soil δ15N are considered immediate indicators, short-term indicators, and long-term indicators, respectively. The four mangrove watersheds are classified into two groups, human-affected and forested mangroves, based on the relative land use ratio (%) of the watersheds. The observed values of the ecological indicators were subsequently compared between two groups of watersheds to determine the relative ecosystem conditions. The results showed that both the leaf δ15N (0 to 9 ‰) and the soil δ15N (1.5 to 8.0 ‰) values are significantly greater in human-affected mangroves than in forested mangroves. The DIN of creek water samples does not indicate an immediate risk of excess N input from human perturbation in mangroves. However, the significant relationships among the indicators reflect the anthropogenic N accumulation potential of mangroves in Okinawa, Japan. These findings are highly important, especially for policymakers, environmentalists, and related stakeholders, for initiating conservation and management practices for mangroves. Controlled, limited, and/or restricted human perturbation; proper management of municipal wastes; and planned use of agrochemicals upon necessity may help reduce anthropogenic N inputs in mangrove ecosystems in Okinawa. [ABSTRACT FROM AUTHOR]

Mononuclear Fe(III) complexes containing an antipyrine Schiff base ligand were prepared and fully characterized, demonstrating a planar tetradentate coordination geometry. These complexes were found to be active for the hydrogen evolution reaction. Catalysis occurs at −1.4 V vs. Fc+/Fc, with an overpotential of 700 mV. The complexes are active electrocatalysts with a turnover frequency of 700 s−1. Furthermore, when paired with a chromophore and sacrificial donor, the complexes are active photocatalysts demonstrating >1700 turnovers during 40 hours of irradiation with a quantum yield of up to 5.4%. The catalysts have also been found to operate in natural water samples of varying salinity. [ABSTRACT FROM AUTHOR]

This study aimed to conduct a multidisciplinary investigation integrating detailed morphology, molecular characterization, water parameters, histopathology alteration, and the trials of treatment of Clinostomum spp. In this study, 300 Nile tilapia (Oreochromis niloticus) were collected from the farmed and wild Nile River at Al Bahr Al Aazam, Giza Governorate to assess Clinostomid infection prevalence. Fish and water samples were collected from private fish farms, and water drains at Dakahlia, and Giza, Egypt. Analysis of the water revealed inadequate water quality, particularly in the fish farms. Snails and piscivorous birds were abundant at fish collection sites. The recovered Clinostomid MCs morphological characteristics and COI gene sequence analysis identified them as Clinostomum complanatum, C. phalacrocoracis, and Euclinostomum heterostomum. Clinostomid MCs disturbed the fish's hematological and biochemical blood parameters. Bath treatment of parasitized fish with praziquantel (2 mg/L for 24 h) revealed a significant reduction in the number of vital MCs vs. infected fish (non-treated). Praziquantel (PZQ) is an effective and safe therapy for controlling Clinostomid infections affecting farmed Nile tilapia. The current findings indicate a link between poor environmental conditions and Clinostomum infections in tilapia. The study highlights the impacts of Clinostomid MCs on fish health and recommends bath treatment with PZQ as an efficient control method for these dangerous parasites to protect human and fish health. [ABSTRACT FROM AUTHOR]

The presence of polycyclic hydrocarbons (PAHs) and microplastics (MPs) in aquatic environments affects the ecosystems and threatens human health. In this study, the abundance, composition, and morphological characteristics of MPs were determined for the first time in the inland freshwater resources of the Konya Closed Basin, Turkey. The abundance of MPs ranged from 1139 to 23,444 particles/m3 and 150 to 3510 particles/kg in the surface water and sediment, respectively. Fragments and fibers were the most abundant MP shapes in the surface waters (51%, 34%) and sediments (29%, 40%), followed by films, pellets, and foams. Transparent and white MPs were present at the highest percentage in surface waters (72%) and sediments (69%), followed by blue, grey, black, brown, and green. In addition, polyethylene, polypropylene, and cellophane were identified as the main polymers in surface waters (34%, 25%, 24%) and sediments (37%, 17%, 31%). In the Konya Closed Basin, 35% of the surface water samples and 54% of the sediment samples were exposed to very high contamination (CF ≥ 6). Surface waters (PLI: 2.51) and sediments (PLI: 1.67) in the basin were contaminated (PLI > 1) with MPs. The 16 PAHs sorbed on MPs in the surface water and sediment ranged from 394 to 24,754 ng/g and from 37 to 18,323 ng/g, respectively. Phenanthrene and fluoranthene were the most abundant PAHs sorbed on MPs in all surface waters and sediments. Two to three-ring PAH compounds sorbed on MPs were also dominantly detected in surface waters and sediments, accounting for 68% and 78% of the total 16 PAHs, respectively. The source of PAHs carried by MPs in the Konya Closed Basin was mainly of petrogenic origin. Incremental lifetime cancer risk (ILCR) results indicated that the maximum ILCR values were higher than the EPA acceptable level (10−6) for child (2.95 × 10−5) and adult (1.46 × 10−4), indicating a potential cancer risk. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) pose an emerging environmental risk impacting food products and ecosystems. This study analyzes over 150,000 entries from food safety authorities and scientific publications from 2017 onwards. Our findings show that fish & seafood, and biota have the highest PFAS concentrations due to environmental contamination and bioaccumulation. Surface water samples also frequently contain PFAS, raising concerns about long-term ecological and human health effects. Comprehensive strategies are essential to mitigate these risks. [ABSTRACT FROM AUTHOR]

Different morphological Cu2O nanoparticles including cube, truncated cube, and octahedron were successfully prepared by a selective surface stabilization strategy. The prepared cube Cu2O exhibited superior peroxidase-like activity over the other two morphological Cu2O nanoparticles, which can readily oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) to form visually recognizable color signals. Consequently, a sensitive and simple colorimetric biosensor was proposed for deoxynivalenol (DON) detection. In this biosensor, the uniform cube Cu2O was employed as the vehicle to label the antibody for the recognition of immunoreaction. The sensing strategy showed a detection limit as low as 0.01 ng/mL, and a wide linear range from 2 to 100 ng/mL. Concurrently, the approximate DON concentration can be immediately and conveniently observed by the vivid color changes. Benefiting from the high sensitivity and selectivity of the designed biosensor, the detection of DON in wheat, corn, and tap water samples was achieved, suggesting the bright prospect of the biosensor for the convenient and intuitive detection of DON in actual samples. [ABSTRACT FROM AUTHOR]

A new molecularly imprinted polymer (MIP)-based disposable electrochemical sensor for dipyridamole (DIP) determination was obtained. The sensor was rapidly prepared by potentiodynamic electrochemical polymerization on a pencil graphite electrode (PGE) using curcumin (CUR) as a functional monomer and DIP as a template molecule. After the optimization of the conditions (pH, monomer–template ratio, scan rate, number of cyclic voltammetric cycles applied in the electro-polymerization process and extraction time of the template molecule) for MIP formation, DIP voltammetric behavior at the modified electrode (MIP_PGE) was investigated. DIP oxidation took place in a pH-dependent, irreversible mixed diffusion-adsorption controlled process. Differential pulse voltammetry (DPV) and adsorptive stripping differential pulse voltammetry (AdSDPV) were used to quantify DIP from pharmaceutical and tap water samples. Under optimized conditions (Britton–Robinson buffer at pH = 3.29), the obtained linear ranges were 5.00 × 10−8–1.00 × 10−5 mol/L and 5.00 × 10−9–1.00 × 10−7 mol/L DIP for DPV and AdSDPV, respectively. The limits of detection of the methods were 1.47 × 10−8 mol/L for DPV and 3.96 × 10−9 mol/L DIP for AdSDPV. [ABSTRACT FROM AUTHOR]

Water samples for bacterial microbiome studies undergo biomass concentration, DNA extraction, and taxonomic identification steps. Through benchmarking, we studied the applicability of skimmed milk flocculation (SMF) for bacterial enrichment, an adapted in-house DNA extraction protocol, and six 16S rRNA databases (16S-DBs). Surface water samples from two rivers were treated with SMF and vacuum filtration (VF) and subjected to amplicon or shotgun metagenomics. A microbial community standard underwent five DNA extraction protocols, taxonomical identification with six different 16S-DBs, and evaluation by the Measurement Integrity Quotient (MIQ) score. In SMF samples, the skimmed milk was metabolized by members of lactic acid bacteria or genera such as Polaromonas, Macrococcus, and Agitococcus, resulting in increased relative abundance (p < 0.5) up to 5.0 log fold change compared to VF, rendering SMF inapplicable for bacterial microbiome studies. The best-performing DNA extraction protocols were FastSpin Soil, the in-house method, and EurX. All 16S-DBs yielded comparable MIQ scores within each DNA extraction kit, ranging from 61–66 (ZymoBIOMICs) up to 80–82 (FastSpin). DNA extraction kits exert more bias toward the composition than 16S-DBs. This benchmarking study provided valuable information to inform future water metagenomic study designs. [ABSTRACT FROM AUTHOR]

A study to assess the uranium exposure due to ingestion of groundwater in Fatehabad district of Haryana has been carried out. Total 49 drinking water samples were collected from different locations of the district. Two groundwater tests taken near the power plant site exceeded the World Health Organization's recommended threshold limit of 30 μg L−1 (WHO in Guidelines for drinking-water quality, 4th edn, World Health Organization, Geneva, pp 1–564., 2011). The average radiological and chemical toxicity risks are below recommended limit. Because of their high organ sensitivity, babies are found to have the highest annual effective dose among the several life stage groups for which it was estimated. Positive correlations were found between the content of uranium in groundwater samples and EC, TDS, salinity, redox potential, and dissolved oxygen whereas a negative connection with pH has been noted. Organ-specific dosage resulting from uranium ingestion has been investigated using the hair compartment model. [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 this study, ultrasound-assisted dispersive magnetic solid phase extraction using toner powder (inexpensive and accessible magnetic sorbent) combined with flame atomic absorption spectrophotometry has been developed for the analysis of cobalt (II) in water and food samples. The influence of parameters (amount of toner powder, sample pH, the concentration of the complexing agent, eluent type and volume, and adsorption time) were studied as a function of the extraction recovery. The proposed method, which has been analytically characterized under its optimum operating conditions, allows the detection of cobalt (II) in the samples with method detection limits of 0.7 μg L−1. The method repeatability, expressed as the relative standard deviation (n = 10, Co2+= 50.0 μg L−1), was 3.1%, while the preconcentration factor was 50. Cobalt(II) was determined in water samples (tap water, river water, mineral water, seawater) and food samples (cabbage and cucumber) with good recoveries (96.0–104.0%) using the proposed method. [ABSTRACT FROM AUTHOR]

This research describes an easy, rapid, and inexpensive magnetic solid-phase extraction (MSPE) approach employing Fe3O4 magnetic nanoparticles modified with cetylpyridinium chloride (Fe3O4@CPC/MNPs) for extracting amoxicillin (AMX) and doxycycline (DOX) after derivatization with 4-chloroaniline as a color reagent. The azo-coupling of AMX and DOX with the color reagent in the alkaline medium caused yellow and yellow-orange azo dyes with maximum absorption wavelengths of 435 and 438 nm, respectively. The UV–Vis spectroscopy was utilized to determine the target analyte after the extraction procedure. Good linearities (R2 > 0.99) in the concentration ranges of 0.03–4.50 and 0.05–6.00 µg/mL were obtained for AMX and DOX, respectively. The experimental detection limits of AMX and DOX were obtained as 0.01 and 0.02 µg/mL, respectively. The developed approach was effectively applied to pre-concentrate and quantify AMX and DOX in environmental water and urine samples. [ABSTRACT FROM AUTHOR]

The objective of this study is to estimate the most common G genotypes of human rotaviruses in addition to the most common sequence of partial VP7 gene in clinical specimens, raw sewage, and Nile water samples in Egypt. A total of five hundred and fifty-four stool specimens were collected from December 2020 to April 2022 from children = 3 years old. Of 554 specimens, 182 specimens were positive for rotavirus VP6 using RT-PCR (32.85%). Using multiplex nested and semi-nested RTPCR, a higher prevalence of common P genotypes than that of common G genotypes was observed in clinical specimens, raw sewage, and Nile water samples. Only common P genotypes could be detected, while P[9] genotype (uncommon P genotype) could not be detected in clinical specimens, raw sewage, and Nile water samples. Of the common G genotypes, G1 was the most prevalent in clinical specimens, raw sewage, and Nile water samples followed by G3. The uncommon G genotypes detected were G9 and G8 in clinical specimens, raw sewage, and Nile water samples. Sequence analysis of 1062 bp of VP7 gene for G1 genotype (the most common G in clinical specimens, raw sewage, and Nile water samples) showed high similarity with human rotavirus Wa strain. In conclusion, the highest frequency of G1 genotype among common G genotypes in clinical specimens, sewage, and Nile water samples may make it a suitable G genotype to be added to the common P genotypes in the candidate recombinant subunit vaccine in Egypt and similar patterns in other countries. [ABSTRACT FROM AUTHOR]

Nitrate pollution is a global environmental problem, and mean nitrate levels have risen by an estimated 36% in global waterways since 1990. Tracing nitrate sources is important for water quality management, and nitrate isotopes (δ15N-NO3− and δ18O-NO3−) are commonly used for this purpose because of the different isotopic compositions of different sources. However, the impact of nitrate sorption on matrix and desorption from matrix on N and O isotopic composition of nitrate in liquid phase has not been well clarified. To explore the mechanism for the changes in nitrate concentration and isotopes in liquid phase during sorption and desorption, this study took a shale sample (enriched in clay minerals and commonly exposed in the Earth), conducted a series of laboratory experiments for nitrate sorption and desorption, and studied the impact of sorption and desorption on nitrate N and O isotopic composition in liquid phase. The results showed that the shale sample exhibited a rapid sorption and desorption rate for nitrate in the surface water samples, with the nitrate concentration in the solution decreasing from 14.3 mg/L to 4.1 mg/L within 5 min. The sorption data fit the Langmuir model better than that of the Freundlich model. The maximum possible sorption (Qmax) for the shale sample was estimated to be 46 μg/g. Preliminary laboratory experiments showed that changes in δ15N-NO3− values were not obvious, and changes in δ18O-NO3− values in liquid phase were minor during sorption and desorption of the shale sample, suggesting that nitrogen isotopic fractionation can be neglected, and the sorption of nitrate by the shale sample has a very limited impact on the distribution of nitrate isotopes in liquid phase. However, the impact of nitrate desorption on the nitrate isotopes in liquid phase depends on the isotopic composition of exchangeable nitrate in the solid phase, which may be related to antecedent water–rock interactions. This study provides important information for elucidating the evolution mechanism of nitrate and its isotopic compositions following sorption-desorption, and is conducive to revealing the nitrogen cycle law in the environment. [ABSTRACT FROM AUTHOR]

The increasing signal‐to‐noise ratio (SNR) is the main reason to use ultrahigh field MRI. Here, we investigate the dependence of the SNR on the magnetic field strength, especially for small animal applications, where small surface coils are used and coil noise cannot be ignored. Measurements were performed at five field strengths from 3 to 14.1 T, using 2.2‐cm surface coils with an identical coil design for transmit and receive on two water samples with and without salt. SNR was measured in a series of spoiled gradient echo images with varying flip angle and corrected for saturation based on a series of flip angle and T1 measurements. Furthermore, the noise figure of the receive chain was determined and eliminated to remove instrument dependence. Finally, the coil sensitivity was determined based on the principle of reciprocity to obtain a measure for ultimate SNR. Before coil sensitivity correction, the SNR increase in nonconductive samples is highly supralinear with B01.6–2.7, depending on distance to the coil, while in the conductive sample, the growth is smaller, being around linear close to the surface coil and increasing up to a B02.0 dependence when moving away from the coil. After sensitivity correction, the SNR increase is independent of loading with B02.1. This study confirms the supralinear increase of SNR with increasing field strengths. Compared with most human measurements with larger coil sizes, smaller surface coils, as mainly used in animal studies, have a higher contribution of coil noise and thus a different behavior of SNR at high fields. [ABSTRACT FROM AUTHOR]

In order to assess the suitability of water sources for human consumption, six water samples were taken from open wells and drinking bore wells in several selected regions in the Kalaburagi district of Karnataka state, India, from December 2020 to January 2022. The analysis found that the local water sources are contaminated. Total dissolved solids, total alkalinity, chloride, calcium, and magnesium levels in the water exceeded the permissible limits. The samples analysed for the presence of microbial contamination indicate a worrying scenario from the point of view of public health. As a result, such studies must be expanded to include open wells and bore wells in individual homes, as well as detailed investigations of the physicochemical and microbiological quality of drinking water sources in Kalaburagi district. [ABSTRACT FROM AUTHOR]

In recent decades, the water management and environmental situation in the Ural River basin was rather tense. This is true for its parts both in the Russian Federation, where the major portion of water resources is formed, and in Kazakhstan. The quantitative and qualitative depletion of water resources in the following years and the abrupt deterioration of the environmental conditions in many parts of the river make it necessary to carry out a large-scale study of the problems at a geosystem level. The article presents the results of studying small rivers in the part of the Ural River basin within the Russian Federation territory, where river runoff and environmental conditions vary under the effect of a combination of natural and anthropogenic factors. The methodological base of the study is the geosystem approach and the basin principle, which enable a comprehensive study of the effect of a combination of natural and anthropogenic factors on the formation of variations of quantitative and qualitative characteristics of watercourses and the ecological conditions in them. The methods of study include generalization and analysis of the data of earlier studies, field studies and observations, sampling water and bottom sediments, zoning of the area under study by the types and levels of anthropogenic load, determination of the character of pollution of watercourses and changes in the ecological conditions in them, depending on the effect of specific types of economic activity. The study revealed specific features of the effect of human economic activity on small rivers and the natural complexes in their drainage areas. The characteristics of the space and time variations in the factors that cause changes in the slope and river runoff are determined. The features of the effect of anthropogenic factors on water quality in water objects and the ecological conditions in them are studied; proposals for ecological rehabilitation, preservation, and recovery of small rivers—tributaries of different orders of the transboundary Ural River—are substantiated. [ABSTRACT FROM AUTHOR]

A new method for the determination of ultra-trace cobalt by ionic liquid-dispersive liquid-liquid microextraction (IL-DLLME) and graphite furnace atomic absorption spectrometry (GFAAS) was developed. The trace cobalt was extracted by DLLME using the homemade reagent 2-(5-bromo-2-pyridylazo)-5-dimethylaminobenzenamine (5-Br-PADMA) as chelating agent, the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6mim][PF6]) as extractant, and acetonitrile (CH3CN) as dispersing agent, and then determined by GFAAS. The factors affecting the cobalt extraction efficiency: the type and volume of extraction solvent and dispersive solvent, the concentration and dosage of chelating agent, and the pH of the solution, were explored using the one-way rotation method. Under the optimized conditions, the cobalt concentration showed excellent linearity in the range of 0.05–1.50 ng/mL with the detection limit of 0.026 ng/mL; the relative standard deviation (RSD) for the determination of the cobalt standard solution with the mass concentration of 1.0 ng/mL was 4.83% (n = 9). From the slope of the linear regression equation for the determination of cobalt obtained after extraction compared with that before extraction, the enrichment factor of the method was found to be 62, and the spiked recoveries were in the range of 94.0–104.4%. The method is characterized by low detection limit, high sensitivity, and environment friendliness as well as convenient and rapid operation for the determination of trace cobalt in water samples. The results of this method are satisfactory. [ABSTRACT FROM AUTHOR]

Due to over exploitation of groundwater, there is a drastic decrease in groundwater level and its quality. The groundwater samples have been analysed to estimate its aptness for domestic and agricultural in Sivakasi Taluk industrial areas. In the course of post monsoon and summer of 2020, twenty two samples have been collected from the research area. The groundwater samples were examined for various parameters like pH, EC, TDS, TA, TH, Ca2+, Mg2+, K+, Na+, Cl−, SO4−, HCO3−, F−, DO and samples were compared with BIS, WHO and ICMR standards. It is inferred through results that EC and TDS values were spiked up due to excess presence of Cl−, Na+, Ca2+, Mg2+, F− and NO3− present in water samples near the industrial areas and natural rock formation. The water samples were evaluated for their suitability for irrigation and were assessed by SAR, % Na, Kelly's ratio and MH, USSL diagram shows majority of the samples are apt for agricultural. Piper plot indicates that majority of the collected samples fall under the Na–Cl category thereafter by Mg- HCO3- Cl, Ca–Mg–Cl and Na + K –Cl types and this infers anthropogenic influences. Gibb's plot shows that the collected samples fall under evaporation dominion field followed by rock-water dominion field of the two seasons. It is recommended to provide Artificial Recharge structures, recharge ponds in the area of research to increase the under-groundwater level and its standard. [ABSTRACT FROM AUTHOR]

AbstractThe distribution of antibiotic resistance genes (ARGs) in Laizhou Bay affects the local socio-economic development. The study aimed to investigate the distribution of ARGs in the rivers that flow into the sea around Laizhou Bay’s southern shore. Water and sediment samples were collected from different typical sites of rivers entering the sea in Weifang, including Mi River, Bai Lang River, Yu River, Wei River, Jiaolai River, Xiaoqing River and Di River. The species and abundance of ARGs in the sediments were characterized and quantified by macro-genome high-throughput sequencing technology. The species distribution of ARGs was compared. In two sediment samples and seven water samples, 24 ARGs types and 1244 subtypes of ARGs were detected, in which multidrug-resistant class was the main ARGs type and FBJ murine osteosarcoma viral oncogene homolog B (fosB) was the dominant ARGs. The types of ARG in the top ten of these samples were the same, although the proportion was different. Dominant ARG subtypes accounted for more than 50% of all the nine samples. This article provides basic data support for pollution status and environmental risk assessment as well as remediation of ARGs in rivers entering the sea along the south coast of Laizhou Bay. [ABSTRACT FROM AUTHOR]

The study of subglacial lakes requires clean access and sampling technologies. One of the most promising alternatives is the newly developed hot-point RECoverable Autonomous Sonde (RECAS), which allows downward and upward ice drilling and subglacial water sampling while the subglacial lake remains isolated from the surface. The original sonde descends downward under the force of gravity, and the borehole trajectory cannot be controlled. However, in certain cases, the sonde would preferably be able to drill at specific angles and directions, enabling it to follow a desired trajectory (e.g., maintaining verticality within the desired range) or bypass obstacles in the ice (e.g., stones and other inclusions). The general principle for the steering RECAS is to adjust the voltage for the electric thermal head heaters, which provides an opportunity to control the heat distribution on the drill head surface, thereby altering borehole trajectory during drilling. In this paper, the general principles of steering RECAS are described, and experimental results on deviational ice drilling with a controllable electric thermal head are discussed. [ABSTRACT FROM AUTHOR]

A thermo‐assisted deep eutectic solvent (DES) based on dispersive liquid‐liquid microextraction followed by gas chromatography with flame ionization detection was developed for the analysis of five phthalate esters in different water samples. In the procedure involved, a DES composed of lidocaine, an amphiphilic amine, and oleic acid, was mixed with the sample assisted by ultrasound, and phase separation was achieved with increasing temperature. The heating of the extraction system induced the change of acid‐base properties of the DES components. Thus, the formation of microdroplets of DES in the sample was provided, and two phases were separated. The structure of the upper hydrophobic layer was characterized by Fourier‐transform infrared spectroscopy. Also, the amount of water in the DES phase was analyzed by mass spectrometer and Karl Fischer titration. Some critical variables on the extraction yield were assessed. The proposed method achieved 1.2–1.3 and 4.1–4.3 µg/L for limits of detection and limits of quantification, respectively. The intra‐day and inter‐day percentage relative standard deviations (n = 5) were determined to be in the range of 4.2–6.2% and 5.1–7.2%, respectively. Ultimately, this method analyzed the five phthalate esters in different water samples with high recoveries. [ABSTRACT FROM AUTHOR]

A simple and quick fiber‐in‐tube solid‐phase microextraction (FIT‐SPME) was introduced for the extraction and determination of nine polycyclic aromatic hydrocarbons followed by a high‐performance liquid chromatography‐ultraviolet detector in refinery water samples. For this purpose, a water‐resistant metal‐organic framework with a high surface area called UiO‐66 has been applied in the form of an electrospun coating on stainless steel wires. After that, all the fibers were packed in the lumen of a stainless‐steel tube to make the extraction phase. Both one variable at a time and experimental design methods have been used to optimize effective parameters on FIT‐SPME. Under optimum conditions, the method demonstrated good linearity between 0.5 and 1000.0 µg/L with a coefficient of determination greater than 0.9906. Furthermore, the limits of detection values ranged from 0.2 to 1.5 µg/L. The intra‐day and inter‐day relative standard deviations were < 8.4% and < 9.7%, respectively. Lastly, the proposed method was applied to extract and determine analytes in four refinery water samples as well as surface water containing high total dissolved solids, and well waters where satisfactory results have been obtained. [ABSTRACT FROM AUTHOR]

AbstractCobalt is beneficial for human activity but has adverse effects when discharged in large quantities. Therefore, its precise and accurate quantification in samples is of importance. Here, a natural deep eutectic solvent (NADES), composed of camphor (H-bond acceptor) and menthol (H-bond donor), has been used for the preconcentration of Co(II) from water samples before determination by a spectrophotometer at 398 nm. The 8-hydroxyquinoline-Co(II) complex was transferred to the NADES using air-assisted dispersive liquid-liquid microextraction (AA-DLLME). The extraction efficiency was enhanced through fine tuning of various parameters, including pH, NADES volume, and quantity of dispersant. Similarly, the centrifugation rate and time, quantity of the complexing agent, matrix effects, and salt concentration were also evaluated. Under the optimized conditions, an enrichment factor of 37.5 and a preconcentration factor of 37.5 were obtained. The limits of detection (LOD) and quantification (LOQ) were 0.44 µg/L and 1.47 µg/L, respectively. For seven replicates of 50 µg/L Co(II), the relative standard deviation was 3.2%. The developed method was employed for the determination of Co(II) in water samples, with quantitative recovery values from 94.5 to 98.5%. [ABSTRACT FROM AUTHOR]

Herein, a novel UV spectrophotometric method coupled with chemometric tools was developed for the simultaneous determination of three fluoroquinolone antibiotics: ciprofloxacin, lomefloxacin, and enrofloxacin. Such integration of UV spectroscopy and chemometric analysis proved to be a simple, rapid, and cost-effective approach for the quantification of these clinically important pharmaceutical compounds and aid in their quality control analysis. The method employed firefly algorithm for variable selection and partial least squares (PLS) regression for model calibration. The developed method was validated by independent test set in addition the accuracy, intra and inter-day precision as per ICH guidelines which showed a satisfactory performance with mean recovery ranged between 98.18 and 101.83 with %RSD < 2. Besides, the developed method displayed ultrasensitive levels with LODs (0.0803, 0.1125, 0.1309 µg/mL) and LOQs (0.2434, 0.3409, 0.3968 µg/mL) for ciprofloxacin, lomefloxacin, and enrofloxacin, respectively. The greenness and blueness of the developed method were also evaluated using the recently proposed Analytical GREEnness metric approach (AGREE) and Blue applicability grade index (BAGI) tools, which showed a high AGREE score of 0.79 and a BAGI score of 77.5. These results indicate that the developed method provides an environmentally friendly alternative to the traditionally used chromatographic techniques, while maintaining high analytical practicability. Finally, the application of the developed methodology was demonstrated on real pharmaceutical and tap water samples, and the results were in good agreement with those obtained by the reference HPLC method indicating the reliability and suitability of the proposed spectrophotometric method for routine analysis of fluoroquinolone antibiotics. [ABSTRACT FROM AUTHOR]

The 72‐foot sailing yacht Eugen Seibold is a new research platform for contamination‐free sampling of the water column and atmosphere for biological, chemical, and physical properties, and the exchange processes between the two realms. Ultimate goal of the project is a better understanding of the modern and past ocean and climate. Operations started in 2019 in the Northeast Atlantic, and will focus on the Tropical Eastern Pacific from 2023 until 2025. Laboratories for air and seawater analyses are equipped with down‐sized and automated state‐of‐the‐art technology for a comprehensive description of the marine carbon system including CO2 concentration in the air and sea surface, pH, macro‐, and micro‐nutrient concentration (e.g., Fe, Cd), trace metals, and calcareous plankton. Air samples are obtained from ca. 13 m above sea surface and analyzed for particles (incl. black carbon and aerosols) and greenhouse gases. Plankton nets and seawater probes are deployed over the custom‐made A‐frame at the stern of the boat. Near Real‐Time Transfer of underway data via satellite connection allows dynamic expedition planning to maximize gain of information. Data and samples are analyzed in collaboration with the international expert research community. Quality controlled data are published for open access. The entire suite of data facilitates refined proxy calibration of paleoceanographic and paleoclimate archives at high temporal and spatial resolution in relation to seawater and atmospheric parameters. Plain Language Summary: The new research sailing yacht Eugen Seibold (ES) enables clean, contamination‐free sampling of air and seawater to better understand the interactions between ocean and climate. For example, the oceans remove increasingly less carbon dioxide (CO2) from the atmosphere the more saturated they are with CO2 (ocean acidification). However, a detailed systematic understanding of air‐sea exchange processes remains to be developed. We analyze air and seawater as well as the exchange of greenhouse gases and other substances such as aerosols and soot (black carbon) between air and seawater at high resolution using modern materials and technologies. Scaled‐down, energy‐efficient, and automated probes developed over the past decade are being used to measure around 50 different characteristics of the marine environment. The work deck at the stern of the boat allows the use of custom‐made water samplers and plankton nets to study the ocean to below 1,000 m depth. In addition, the new data enables a better understanding of past ocean archives, such as the marine plankton accumulated in seafloor sediments, to reconstruct past climate changes. From 2019 to 2022, the S/Y ES sailed in the eastern North Atlantic and will operate in the tropical eastern Pacific until 2025. Key Points: New research platform for contamination‐free sampling of the water column and atmosphere of biological, chemical, and physical propertiesComprehensive marine geochemical analyzes including carbon (e.g., CO2) in air and sea surfaceProxy calibration of paleoclimate archives at high temporal and spatial resolution in relation to seawater and atmospheric parameters [ABSTRACT FROM AUTHOR]

Bacteria play a crucial role in pollutant degradation, biogeochemical cycling, and energy flow within river ecosystems. However, the underlying mechanisms governing bacterial community assembly and their response to environmental factors at seasonal scales in subtropical rivers remain poorly understood. In this study, we conducted 16S rRNA gene amplicon sequencing on water samples from the Liuxi River to investigate the composition, assembly processes, and co-occurrence relationships of bacterial communities during the wet season and dry season. The results demonstrated that seasonal differences in hydrochemistry significantly influenced the composition of bacterial communities. A more heterogeneous community structure and increased alpha diversity were observed during the dry season. Water temperature emerged as the primary driver for seasonal changes in bacterial communities. Dispersal limitation predominantly governed community assembly, however, during the dry season, its contribution increased due to decreased immigration rates. Co-occurrence network analysis reveals that mutualism played a prevailing role in shaping bacterial community structure. Compared to the wet season, the network of bacterial communities exhibited higher modularity, competition, and keystone species during the dry season, resulting in a more stable community structure. Although keystone species displayed distinct seasonal variations, Proteobacteria and Actinobacteria were consistently abundant keystone species maintaining network structure in both seasons. Our findings provide insights into how bacterial communities respond to seasonal environmental changes, uncovering underlying mechanisms governing community assembly in subtropical rivers, which are crucial for the effective management and conservation of riverine ecosystems. [ABSTRACT FROM AUTHOR]

In order to discharge ballast in waters of the USA and Member States of the IMO, a vessel must comply with ballast water discharge standards (BWDS). In most cases, this involves use of a Type-Approved ballast water management system (BWMS). Although rigorous efficacy testing is required to gain Type-Approval status, there are currently no requirements for regular compliance checks after a BWMS has been commissioned. Routine compliance checks, to enumerate organisms in treated discharges, are currently the only way to know if a system is meeting a BWDS. This policy brief has two objectives: 1) Highlight the importance of routine collection and analysis of treated ballast water discharges, and 2) Present technical considerations to perform compliance assessments, highlighting good practices for sample collection and analysis and advising of potential obstacles. These assessments are necessary to inhibit the spread of non-indigenous species. [ABSTRACT FROM AUTHOR]

The Heilongjiang River is one of the largest rivers in the cool temperate zone and has an abundant fish source. To date, the microbiota community in water samples and fish guts from the Heilongjiang River is still unclear. In the present study, water samples and fish guts were collected from four locations of the Heilongjiang River during both the dry season and the wet season to analyze the spatio-temporal dynamics of microbiota communities in the water environment and fish guts through 16s ribosome RNA sequencing. The water qualities showed seasonal changes in which the pH value, dissolved oxygen, and total dissolved solids were generally higher during the dry season, and the water temperature was higher during the wet season. RDA indicated that higher pH values, dissolved oxygen, and total dissolved solids promoted the formation of microbiota communities in the water samples of the dry season, while higher water temperature positively regulated the formation of microbiota communities in the water samples of the wet season. LEFSe identified five biomarkers with the most abundant difference at the genus level, of which TM7a was upregulated in the water samples of the dry season, and SM1A02, Rheinheimera, Gemmatimonas, and Vogesella were upregulated in the water samples of the wet season. Pearson analysis revealed that higher pH values and dissolved oxygen positively regulated the formation of TM7a and negatively regulated the formation of SM1A02, Rheinheimera, Gemmatimonas, and Vogesella (p < 0.05), while higher water temperature had the opposite regulatory roles in the formation of these biomarkers. The relative abundance of microbiota diversity in fish guts varies greatly between different fish species, even if the fishes were collected from the same water source, indicating that dietary habits and fish species may be key factors, affecting the formation and construction of microbiome community in fish gut. P. glenii, P. lagowskii, G. cynocephalus, and L. waleckii were the main fish resources, which were collected and identified from at least six sample points. RDA indicated that the microbiota in the water environment regulated the formation of microbiota community in the guts of G. cynocephalus and L. waleckii and had limited regulated effects on P. glenii and P. lagowskii. The present study identified the regulatory effects of water qualities on the formation of microbiota communities in the water samples and fish guts, providing valuable evidence for the protection of fish resources in the Heilongjiang River. [ABSTRACT FROM AUTHOR]

In this study, water samples were collected from four locations: a well, a tap, the Kharazi Valley, and the Tigris River. Samples were taken over three months--February, March, and April--and the following measurements were recorded: pH, TDS (Total dissolved solids), and temperature. The temperature of each water sample, measured during collection, ranged between 16°C and 25°C. The pH ranged from 7.3 to 8.8, while TDS reached the highest value in the river sample at 830, and for the other samples, a range between 221 and 360 was recorded. The samples were then inoculated on corn meal agar (CMA). In February, Penicillium spp. was the most prominent fungus, appearing in 62% of samples. In March, the yeast Candida spp. was the most common at 36%, and in April, Candida spp. remained prevalent, followed by Penicillium spp. at 26%, Fusarium spp. at 24%, and Aspergillus flavus, which appeared in samples collected from the Kharazi Valley. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a leading cause of human gastroenteritis associated with seafood consumption. The present study aimed to investigate the occurrence and risk assessment of V. parahaemolyticus isolated from live Indian black clams, sediment, and water samples collected from shellfish harvesting areas located along the south-west coast of India. Out of the total 72 samples collected, 55.6% revealed the presence of V. parahaemolyticus; the highest occurrence was observed in shellfish samples. The presence of tdh and trh virulence genes was screened by multiplex PCR. Virulence genes could be detected in 25.8% of the strains; 19.35% of them were trh positive and 3.2% were tdh positive, while 3.2% of strains exhibited the coexistence of both virulence genes. Antimicrobial resistance (AMR) determined by the disk diffusion method revealed that 87% of the strains were multiple drug resistant and exhibited 21 diverse resistance patterns. The overall multiple antibiotic resistance (MAR) index values ranged from 0 to 0.8. To the best of our knowledge, this is the first report to document the presence of pathogenic and multidrug-resistant V. parahaemolyticus in shellfish harvesting areas of the Indian sub-continent. The study reveals possible health hazards associated with consuming shellfish harvested from the study area. [ABSTRACT FROM AUTHOR]

Acanthamoebae spp. are considered the most commonly occurring free-living amoebae (FLA) in the environment. Their high resilience enables them to thrive in different types of environments. Using purposive sampling, 80 surface water samples were collected from identified coastal sites in Mariveles, Bataan, and Lingayen Gulf (40 water samples for each). Nineteen (23.75%) of the 80 water samples yielded positive amoebic growth during the 14-day culture and microscopic examination. The polymerase chain reaction confirmed Acanthamoeba spp. DNA in isolates MB1, A3, A4, A7, C5, and D3 using JDP1 and JDP2 primer sets. Further sequencing revealed that the isolates belonged to Acantha- moeba sp., Acanthamoeba culbertsoni, Acanthamoeba castellani, and Acanthamoeba genotype T4. The sequences were deposited in GenBank and registered under accession numbers PP741651, PP767364, PP741728, PP741729, PP767365, and PP767366, respectively. Potential risk factors such as waste disposal, expansion of human settlements to coastal locations, and soil runoffs in these environments should be controlled to mitigate the proliferation of potentially pathogenic strains of FLAs. [ABSTRACT FROM AUTHOR]

Natural hot springs are ideal places and environmental matrices that offer relaxation to people and microorganisms of different types. A total of 40 surface water samples were collected from the five identified collection sites, eight water samples for each site. Collection sites are designated 200 m apart to cover the entire study site. Surface water samples were collected approximately 10–20 cm from the surface. Water samples were filtered, cultured, and microscopically observed for 14 days. After 14 days of cultivation, eight (20%) water samples revealed cystic and trophozoite stages. Polymerase chain reaction using JDP1 and JDP2 specific primers confirmed the presence of Acanthamoeba spp. from two of our isolates in the hot spring, isolates 1.1 and 5.1. Further sequencing revealed that the isolates are Acanthamoeba T20 and Acanthamoeba genotype T7. Sequences were deposited to GenBank and were assigned accession numbers PP741726 and PP741727, respectively. The isolation of Acanthamoeba spp. in hot springs has significant health implications, especially for those who use it for recreational activity. Private resort owners are highly encouraged to regularly monitor and maintain hot spring resorts to avoid future infections. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the levels of fluoride in drinking water and its health impact in Semema, Tigray, Ethiopia. Water samples were collected in February, March and April from three potential spring water sources, namely May Atkaru, May Sensela and May Liham. Each sample was analyzed for a variety of physicochemical parameters including fluoride using standard APHA procedures through double beam UV–Visible spectrophotometer, atomic absorption spectrophotometer and titrimetric methods. All the measured physicochemical parameters except hardness (345.78–368.35 mg/L) and alkalinity (231.3–354.6 mg/L) were recorded below the WHO permissible limit set for drinking water. The amount of fluoride in May Atkaru (4.00 mg/L) and May Sensela (3.89 mg/L) was significantly greater than the WHO permissible limit set for drinking water, 1.5 mg/L. Moreover, HQ . 1 from May Atkaru and May Sensela revealed the possibility of dental and skeletal fluorosis over extended exposure to fluoride irrespective of age and sex variations. This confirmed people in the area with mottled teeth are vulnerable to the excessive consumption of fluoride, which poses health risks. Therefore, it needs immediate interventions to minimize the debilitating effect of fluoride in drinking water by creating awareness among the community and policymakers to introduce low-cost defluoridation methods. [ABSTRACT FROM AUTHOR]

Though iron is one of the vital micronutrients in biological systems excess of which is associated with various illness. Consumption of contaminated water and crops because of its extensive industrial utility is one of the major sources for excess iron in living beings. Hence, we have designed a sensor based on carbon nanoparticles for the detection of Fe (III) and we have also attempted to estimate Fe (III) in spiked water samples. Carbon nanoparticles (CNP) with quantum yield of 40.2 % was synthesized by solid state synthesis from aromatic molecular precursors unlike conventional synthesis methodology. The particle size, stability and optical properties of CNP were investigated by microscopic and spectroscopic techniques. CNP manifested a naked color change from colorless to yellow in presence of Fe (III) and 72 % of CNP's emission was quenched at 487 nm on excitation at 377 nm by Fe (III). The detection time was less than a second and limit of detection was calculated as 0.248 µM. The mechanistic aspect of detection was investigated and applicability of CNP was examined in spiked water samples. [ABSTRACT FROM AUTHOR]

A novel flavonol-based fluorescent probe, Fla-DNT, has been synthesized for the rapid and specific detection of H2S. Fla-DNT exhibits excellent selectivity and anti-interference properties, a short response time (4 min), large Stokes shift (138 nm), and low detection limit (1.357 µM). Upon exposure to H2S, Fla-DNT displays a remarkable increase in fluorescence intensity at 542 nm. Meanwhile, the recognizing site of H2S was predicted through Electrostatic potential and ADCH charges calculations, while the sensing mechanism of H2S was determined via HRMS analysis and DFT calculation. More importantly, the probe owes multiple applications, such as a recovery rate ranging from 92.00 to 102.10% for detecting H2S in water samples, and it can be fabricated into fluorescent strips to track H2S production during food spoilage by tracking color changes, thereby enabling real-time monitoring of food freshness. The bioimaging experiments demonstrate the capability of Fla-DNT to detect both endogenous and exogenous H2S in living cells. These results provide a reliable method and idea for H2S detection in complex environments. [ABSTRACT FROM AUTHOR]

Objective To analyze the distribution characteristics of perchlorate in drinking water in Chengdu and its influencing factors and explore the health risks associated with perchlorate exposure through drinking water among Chengdu residents, under the context of the initial implementation of national limit standards and clarified detection methods. Methods In 2023, an investigation was conducted at 47 water plants in Chengdu (including all municipal water plants and all large rural water plants using surface water as a source). Water samples from the source, treated water, and tap water were collected during both wet and dry seasons for perchlorate testing. The temporal and spatial distribution characteristics of perchlorate in the three types of water samples and their influencing factors were analyzed to assess the health risks of perchlorate exposure through drinking water for Chengdu residents. Results The overall detection rate of water samples was 29.8%, with concentrations below national limit standards, and perchlorate was detected in all three types of water. The detection rates during the dry season were higher than those during the wet season, with no differences in detected concentrations. There were no differences in detection rates among the three types of water samples during the dry season, while the detection rate of treated water during the wet season was higher than that of source water, with no differences in detected concentrations across both seasons. Perchlorate was detected in source water from the Minjiang River system, but not in the Tuojiang River system. The detection rate of surface water source samples was higher during the dry season than during the wet season, while there were no differences in detection rates for groundwater sources across both seasons. Only the treated water that underwent disinfection had a higher detection rate compared to fully treated water, with no differences in detected concentrations. The detection rates and concentrations of treated water using chlorination and chlorine dioxide disinfection methods showed no differences. The 19 water plants where perchlorate was detected in all three types of water were primarily located in areas with high population density in the Minjiang River basin. Conclusion Perchlorate contamination exists in Chengdu’s drinking water, with more severe pollution during the dry season and a broader contamination area in the Minjiang River system. The current treatment processes at water plants do not effectively remove perchlorate, and there may be a declining trend in perchlorate pollution levels in surface water. At this stage, the health risk of perchlorate exposure through drinking water for Chengdu residents is considered acceptable. It is recommended that the government continue to strengthen source control, technical guidance, and monitoring to ensure ongoing public health safety. [ABSTRACT FROM AUTHOR]

A simple, fast, and low-cost pre-concentration methodology based on the application of solid-phase extraction coupled to layered double hydroxides (LDHs) and capillary electrophoresis was developed for the determination of naproxen (NPX), diclofenac (DFC), and ibuprofen (IBP) in environmental sample waters. A systematic study of the LDH composition was designed, including the effects of interlayer anions (NO3−, Cl−, CO32−, BenO−, and SDS−) and the effect of molar ratio (Mg:Al). The optimal composition of MgAl/Cl−-LDH (Mg:Al; 1.5:1.0) was coupled to an SPE system: pH (neutral pH), LDH amount (15 mg), and extraction capacity ranged from 79.71 to 83.11% for the three anti-inflammatory non-steroidal agents analyzed. A recovery rate of up to 80.87% was obtained when 0.01 M chloride acid in methanol was used as the eluent and 50 mL of sample was used. Under optimal conditions, the linear range of the calibration curve ranges from 18.02 to 200 μg L−1, with limits of detection ranging from 6.03 to 18.02 μg L−1 for the three NSAIDs. The precision of the methodology was evaluated in terms of inter- and intra-day repeatability, with %RSD < 10% in all cases. The proposed method was applied to analyze environmental water samples (bottle, tap, cistern, well, and river water samples). The developed method is a robust technique capable of combining with other analytical methods to quantitatively determine anti-inflammatory non-steroidal agents. [ABSTRACT FROM AUTHOR]

Utilizing the full potential of reproducible biomass resources is crucial for the sustainable development of humanity. In this study, biochar (MPC) was prepared through the microwave-assisted pyrolysis of sugarcane bagasse. Subsequently, Co nanoparticles were introduced by microwave-assisted hydrothermal treatment to form a highly dispersive Co/MPC material. Characterization results indicated that Co nanoparticles were wrapped by thin carbon layers and uniformly dispersed on a carbon-based skeleton via a microwave-assisted hydrothermal synthesis approach, providing high-activity space. Thus, the prepared material was limited to glassy carbon; on the electrode surface, a cobalt-based sensing platform (Co/MPC/GCE) was built. On the basis of this constructed sensing platform, a linear equation was fitted by the concentration change of current signal I and H2O2. The linear range was 0.55–100.05 mM; the detection limit was 1.38 μM (S/N = 3); and the sensitivity was 103.45 μA cm−2 mM−1. In addition, the effect this sensor had on H2O2 detection of actual water samples was conducted by using a standard addition recovery method; results disclosed that the recovery rate and RSD of H2O2 in tap water samples were 94.0–97.6% and 4.1–6.5%, respectively. [ABSTRACT FROM AUTHOR]

Bacteriophage therapy is a promising strategy used to treat antimicrobial-resistant or persistent bacterial infections. More recently, the clinical utility of bacteriophages has been rediscovered due to the rise of multi-drug resistance and their potential use in clinical practice as an additional treatment option. In this study, local municipal wastewater facilities, hospital wastewater systems, and freshwater reservoirs were evaluated for the presence of lytic bacteriophages. These phages were isolated using conventional phage isolation techniques: water sample collection and processing, pre-enrichment with the host bacteria, the spot test, and the double-layer method. Plaques were selected according to their morphology and lytic activity on the target bacteria. Clinical isolates and reference strains belonging to the ESKAPE group were the targets during phage isolation. A total of 210 lytic plaque morphotypes with activity against ESKAPE strains were isolated from 22 water samples. Each isolate was qualitatively evaluated for its ability to inhibit the growth of its host strain. Thirty-one translucent plaques with apparent lytic activity were selected for purification. Of these, 87.1% were isolated from wastewater samples, and 12.9% were isolated from flowing freshwater. Specifically, the phages isolated from the freshwater samples targeted Staphylococcus aureus strains, and no phage from Enterococcus faecium strains was isolated. In conclusion, wastewater samples are a suitable source for the isolation of exogenous lytic phages; however, freshwater could be considered an alternative source for the isolation of lytic phages. [ABSTRACT FROM AUTHOR]

Identified as a potential reference pathogen by the WHO Guidelines for Drinking-Water Quality, Rotavirus (RV) is among the main enteric viruses that cause waterborne diseases. The aim of this study was to identify and correlate the presence of RV in collective and individual water sources of rural communities in the state of Goiás, within the seasons in which the collections were made (rainy and dry seasons). For this, 86 water samples in the dry period and 160 samples in the rainy period were collected. Concentration of water samples, extraction of viral genetic material and molecular tests were performed. When analyzing the presence of RV in the samples, taking into consideration the period studied, RV was found to be more prevalent in the dry season (54.7%) than in the rainy season (20%), showing a strong statistical association with the dry season (p-value < 0.001). The presence of pathogenic microorganisms in water is a public risk issue, enabling the emergence of outbreaks, endemics and epidemics. In the present research, there was an association between the presence of Rotavirus and the dry period of the year when compared to the rainy period. [ABSTRACT FROM AUTHOR]

Despite a surge in microbiota‐focused studies in teleosts, few have reported functional data on whole metagenomes as it has proven difficult to extract high biomass microbial DNA from fish intestinal samples. The zebrafish is a promising model organism in functional microbiota research, yet studies on the functional landscape of the zebrafish gut microbiota through shotgun based metagenomics remain scarce. Thus, a consensus on an appropriate sampling method accurately representing the zebrafish gut microbiota, or any fish species is lacking. Addressing this, we systematically tested four methods of sampling the zebrafish gut microbiota: collection of faeces from the tank, the whole gut, intestinal content, and the application of ventral pressure to facilitate extrusion of gut material. Additionally, we included water samples as an environmental control to address the potential influence of the environmental microbiota on each sample type. To compare these sampling methods, we employed a combination of genome‐resolved metagenomics and 16S metabarcoding techniques. We observed differences among sample types on all levels including sampling, bioinformatic processing, metagenome co‐assemblies, generation of metagenome‐assembled genomes (MAGs), functional potential, MAG coverage, and population level microdiversity. Comparison to the environmental control highlighted the potential impact of the environmental contamination on data interpretation. While all sample types tested are informative about the zebrafish gut microbiota, the results show that optimal sample type for studying fish microbiomes depends on the specific objectives of the study, and here we provide a guide on what factors to consider for designing functional metagenome‐based studies on teleost microbiomes. [ABSTRACT FROM AUTHOR]

In this study, the composition, distribution, and seasonal changes of epilithic diatoms were investigated to reveal the water quality and trophic level of Büyükçekmece Reservoir, which is one of the essential freshwater sources for İstanbul, Türkiye. Water and diatom samples were collected on the same day from all stations, and sampling was only on one day for a specific sampling season. Seventy-six taxa belonging to 30 genera were identified, two of which were centric and 74 were pennate diatoms; 12 of the epilithic species were newly-reported diatoms for the Büyükçekmece Reservoir. The highest number of epilithic diatom species was obtained in November, and the lowest was in February. According to relative abundance, Gomphonella olivacea was abundant in February, Cymbella lange-bertalotii in May, and Cocconeis placentula in August and November. According to the diatom-based water quality indices, the Büyükçekmece Reservoir belongs to I (very good, oligotrophic) and II (good, meso-oligotrophic) water quality classes. Redundancy analysis was used to reveal the association of epilithic diatom species with ecological variables, and it was determined that Silicate-Si, Ammonium-N, and temperature were the most effective variables in the distribution of epilithic diatoms. [ABSTRACT FROM AUTHOR]

Microplastics (MPs), or tiny pieces of plastic, have become a major global environmental problem because of their ubiquitous availability and possible risks to aquatic ecosystems. Surma is one of the vital rivers in Bangladesh located in the northeast part, with higher chances of MP pollution due to different anthropogenic reasons. In this instance, we carried out the investigation on the abundance, distribution, and characteristics of MPs in the sediment and surface water of the river. Samples were collected from 15 major locations of the Surma river flowing through Sylhet municipality. MPs particles were isolated from sediments and water samples utilizing techniques like sieve analysis, wet peroxide oxidation, density separation, and filtration and then characterized using a stereomicroscope. The abundance of MPs recorded 8 to 18 items/L in water samples (mean ± SD: 12.33 ± 2.98 items/L) and 360 to 1120 items/kg in sediment samples (mean ± SD: 522.67 ± 197.84 items/kg). The prominent size, shape, and color of MPs isolated from sediments were 1–2 mm sizes (24.49%), fragments (47.71%), and black (30.65%). However, for water samples, 1–2 mm sizes (37.22%), fiber shapes (48.48%), and transparent colors (38.46%) were dominant features. Conspicuously, in both sediment and water samples, there was a higher prevalence of smaller sized particles, posing a significant threat to the ecosystem. This heightened risk stems from the increased likelihood of ingestion by microorganisms, as well as the larger surface area of these particles, which may serve as vectors for other pollutants like organic pollutants and heavy metals. A greater abundance of fibers suggests an increased presence of lightweight particles in the water and sediment. Furthermore, the transparent color of the MPs in water might be impacted by prolonged weathering in the river, while the presence of black‐colored MPs in sediment points to the existence of plastic pellets originating from industrial and diverse sources. Future studies should concentrate on long‐term and broad monitoring, ecological effects, and practical mitigation techniques for MPs, providing essential baseline data to guide the formulation of policies in developing nations. Practitioner points: 12.33 items/L in surface water and 522.67 items/kg in sediment were observed.High correlation indicates a single MP source in mainstream water, differing from sediment.Fiber shapes, black, and transparent colored MPs are dominant.Higher prevalence of smaller sized MPs, posing a significant threat to the aquatic ecosystem. [ABSTRACT FROM AUTHOR]

The background differences in water content of different samples have a very strong influence on the robustness of near-infrared spectroscopy (NIRS). For this reason, this study simulated typical biological water matrix samples with formulated hemoglobin (Hb), glucose (Glc), and distilled water, and attempted to use four different intelligent spectral variable selection algorithms [Competitive Adaptive Reweighted Sampling (CARS), Randomized Frog Hopping Algorithm (RF), Genetic Algorithm (GA), and Variable Projection Importance Algorithm (VIP)] to perform the Hb water interference-resistant feature band preferences, while combining partial least squares (PLS) in parallel to build a robust quantitative model of Hb. In addition, the applicability and validity of the model were validated using three prediction sets P1, P2, P3 with different water backgrounds (the formulation method and composition were kept the same, and only the water content increased sequentially). The results showed that RF, GA, and VIP could effectively screen out the characteristic wavelengths of Hb with low sensitivity to water changes and successfully correct the water effect, but due to the large number of characteristic variables they screened out and the existence of a large number of redundant and water interference variables, this ultimately made the model's robustness less than ideal. The CARS algorithm performed the best, and the RMSEP of the three prediction sets were 0.016, 0.017, and 0.038, which is closer to the RMSECV of the calibration set. Therefore, NIRS combined with the variable selection can reduce the effect of water on model robustness and improve the prediction accuracy of the model by the method of selecting effective wave number intervals, and CARS may be one of the ideal algorithms to solve such problems. [ABSTRACT FROM AUTHOR]

The study utilizes the colorimetric method (involving 1,5-diphenylcarbazide and potassium thiocyanate as complexing agents), computer vision, and machine learning (ML) regression algorithms to determine the content of Cr (VI) and Fe (III) in water samples. To process digital images of water samples, the integration technique utilized a flatbed scanner known as the CanoScan LiDE 100, operating as a digital image capture device, and its performance was compared to that of conventional instruments. The study reveals that PolyReg and SVR-Poly are the most reliable ML regression algorithms for processing color space data (G and B of RGB, c* of CIELch, and b* of CIELab) of digital images of water samples that contain Cr (VI) and Fe (III). The mean absolute percentage error (MAPE) of the ML regression algorithms PolyReg and SVR-Poly for determining the content of Cr (VI) and Fe (III) is < 10% (with 8.48% error for Cr (VI) determination using PolyReg G of RGB and 6.78% error for Fe (III) determination using PolyReg B of RGB) in the estimation algorithm model. The Mean Absolute Percentage Error (MAPE) indicates that the prediction method is highly accurate. The Limit of Detection (LOD) value of the flatbed scanner colorimetric method integrated with PolyReg G of Red–Green–Blue (RGB) for Chromium (VI) and Blue of RGB for Iron (III) is approximately 0.02 mg/L. The Limit of Detection (LOD) for Chromium (VI) and Iron (III) is 0.0209 mg/L and 0.0257 mg/L, respectively. The limit of detection (LOD) values from this technique are superior to those obtained from certain UV–vis spectrometric and colorimetric methods. The low LOD values demonstrate that this technique is suitable for estimating the concentration of Cr (VI) and Fe (III) in water samples for quality assessment purposes, as these values are below the maximum concentration levels established by various regulations, including US-EPA, ASEAN, and EECCA. [ABSTRACT FROM AUTHOR]