Water Samples Research Articles

Synergistic surface ligand modification of Ni-Pt bimetallic nanozymes: Enhanced catalytic activity and versatile detection of penicillin

Monitoring and control of penicillin (PCN) in the environment are critically important for reducing the emergence and dissemination of antibiotic-resistant bacteria, ensuring food safety, and safeguarding human health. In this study, we introduce a novel and facile strategy for modulating the catalytic activity of bimetallic nanozymes through surface ligand engineering. Experimental activity assays and theoretical model calculations confirm that Ni-Pt nanozymes coated with polyallylamine hydrochloride (PAM) exhibit significantly enhanced peroxidase (POD)-like activity compared to their counterparts coated with conventional polyvinyl pyrrolidone (PVP) and polystyrene sulfonate (PSS). Leveraging the potent reactivity between PCN and the hydroxyl radicals (∙OH) generated by Ni-Pt@PAM catalytic system, we have developed a colorimetric sensor that directly detects PCN, demonstrating a linear response range from 0.5 to 10 μM and detection limit as low as 13.5 nM. Additionally, a fluorescent sensing platform utilizing self-synthesized fluorophore Rho-Si based on inner filter effect (IFE), has been successfully established. These two sensing platforms, capable of generating both colorimetric and fluorescent signals, enable sensitive, rapid, and straightforward detection of PCN in water samples. This work not only offers an innovative approach for tuning the POD-like activity of Ni-Pt bimetallic nanozymes but also presents a promising avenue for their application in PCN monitoring.

Stacking in electrophoresis by electroosmotic flow-assisted admicelle to solvent microextraction.

An in-line sample concentration method for capillary electrophoresis called admicelle to solvent microextraction was proposed. In this technique, analytes were trapped in the cetyltrimethylammonium bromide admicelles formed in situ on the negatively charged capillary surface. A solvent plug was then partially injected hydrodynamically to collapse the admicelles, which liberated and focused the analytes at the solvent front. Voltage was applied across the capillary, completing the stacking process. Various solvents, namely, methanol, ethanol, and acetonitrile, were investigated. The optimal solvent for solvent to admicelle microextraction was 30% acetonitrile in 24mM sodium tetraborate (pH 9.2). Sample injection time and solvent to sample injection ratio were also optimised. For this demonstration, the optimum sample injection time and solvent to sample injection ratio were 320s and 1:2, respectively. Using the optimum conditions, UV detection sensitivity was enhanced 132-176-fold for the model anions. The LOQ, %intra-/inter-day (n = 6/n = 12, 2days) repeatability, and linearity (R2) of admicelle to solvent microextraction were 0.08-2µg/mL, 1.9-3.9%, 2.8-4.9%, and 0.992, respectively. Admicelle to solvent microextraction was applied to the analysis of various fortified water samples, with good repeatability (%RSD = 0.5-3.6%), and no matrix interferences.

Ecohydrological Dynamics and Temporal Water Origin in a European Mediterranean Vineyard

ABSTRACTViticulture is an essential sector in agriculture as wine production plays a vital role in the socio‐economic life of many countries, especially in the Mediterranean area. Grapevines are a valuable, long‐lived species able to grow in hot and dry regions. We currently do not know whether rain‐fed grapevines entirely rely on deep soil water or make substantial use of shallow water from summer precipitation events. Without knowing this, we poorly understand what fraction of summer precipitation inputs contributes to grapevine transpiration. This has implications for how we quantify grapevine‐relevant precipitation budgets and for predicting the impacts of climate change on grape and wine production. We investigated grapevine water use in a vineyard in the Chianti region, central Italy. During the growing season of 2021, we monitored precipitation and soil moisture at 30‐ and 60‐cm depth. We collected over 250 samples for stable isotope analysis from rainfall, soil, and plants. Since traditional plant water sampling is problematic for grapevines, we collected samples from shoots, leaves, and condensed leaf transpiration after sealed plastic bags were wrapped around a shoot. We use these alternative plant samples to reconstruct the isotopic signal in the xylem water and infer the plant's seasonal water origin throughout the growing season. The analysis of the seasonal origin of water revealed that, throughout the growing season, soil water and plant water received disproportional contributions by rain that had fallen in the winter, even when compensating for the Mediterranean climate of the area. Only in late summer did the grapevines use substantial amounts of summer rainfall, whose contribution occasionally became dominant. These results provide a better understanding of ecohydrological interactions and uptake dynamics in valuable socio‐economic agroecosystems such as vineyards.

Construction of fluorescent probe based on phenoxazine for the detection of N2H4 in environmental, biological and food samples

Hydrazine (N2H4) is widely used in agrochemicals and pharmaceuticals, but unintentional releases of hydrazine can be transmitted through food, organisms and the environment, ultimately posing a serious hazard to human health. Consequently, the development of a rapid and sensitive analytical tool for the detection of N2H4 is necessary. In this study, we present the synthesis and application of a novel molecular probe (Probe PM). The probe is characterised by its simple synthesis, high yield and a range of analytical properties including very high sensitivity (limit of detection as low as 17.1 nM) and a pronounced fluorescence spectral blue shift of 146 nm. These attributes have enabled the successful implementation of Probe PM in the qualitative and quantitative detection and visualization of hydrazine in diverse environmental and biological matrices, including water samples, soil samples, food products, and biological systems. The probe has great potential for detecting environmental and food safety.

Experimental Study on the Impact of Sorption-Desorption on Nitrate Isotopes

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.

The Isotopic Composition of Selected Phosphate Sources (δ18O-PO4) from the Area of the Vistula and Bug Interfluve (Poland)

Phosphorus belongs to the crucial bioelements that cause eutrophication, and phosphates, easily assimilated by organisms, are widespread in the environment. Phosphates can be of natural or anthropogenic origin and can derive from various point or non-point sources. Knowledge about the origin of nutrients is necessary to effectively manage, protect, and revitalize water resources. To recognize various phosphate sources in the study area of our research, i.e., the Vistula and Bug interfluve (SE Poland), we used the oxygen isotopic signature of phosphate ions (δ18O-PO4), which has been successfully used in recent decades as a tracer of phosphorus cycling in water studies. We measured the δ18O-PO4 of dissolved inorganic phosphates (DIPs) extracted from various phosphate sources. The obtained results are as follows: For springs, the δ18O-PO4 value varied from +14.8‰ to +18.5‰; for riverine samples, from +10.3‰ to +18.6‰, which were significantly location-dependent; while waste water treatment plant effluents ranged from +12.4‰ to +15.6‰. Two tested drainage water samples had similar isotopic compositions (+16.7‰ and +17.3‰). In the case of two analyzed bedrock samples, the δ18O-PO4 values, which were similar (+20.5‰ and +21.7‰), are close to the existing data on sedimentary bedrocks derived from similar geological periods. The obtained results can be helpful in future research aimed at identifying phosphate sources and P cycling in the studied area.

Nation-wide monitoring campaign of 49 biocides and surfactants in surface waters and wastewaters

Despite their intensive use and their impact on ecosystems, biocides and surfactants are still poorly regulated and poorly monitored at large scale. In the frame of the revision of the national regulatory surveillance plan of surface waters, France planned in 2018 a monitoring campaign at national scale focused on these two types of substances of very emerging concern. Forty-nine contaminants (32 biocides and 17 surfactants) were investigated in surface water and sediment samples from 91 sampling sites, and in effluent and sludge samples of 7 wastewater treatment plants (WWTP), in mainland France and overseas regions. Between 33 and 52 % of the target contaminants were quantified at least once in water and sediment. High frequencies of quantification were observed for the surfactants (up to 91 % in water samples and up to 57 % in sediment samples for LAS C10-C13) and for the biocides (up to 64 % for fipronil in water samples and up to 90 % for methyl nonyl ketone in sediment samples). The median concentrations of surfactants were up to 2 μg/L in mainland surface water samples and up to 528 μg/kg in sediment samples, and for biocides, the median concentrations were up to 0.18 μg/L in mainland surface water samples and up to 104 μg/kg in sediment samples. PNEC exceedances in water and sediment were determined for both types of substances. The analysis of effluent and sludge suggested significant but not total removal of these substances in the WWTP. Temporal and spatial variations of the concentrations of both types of substances in surface water samples were also observed, suggesting both punctual and diffuse contamination sources of the surface water investigated.

Synthesis of a bimetal-organic framework-cobalt oxide nanoflowers (Ni/Co-MOF@Co3O4 NFs) for sensitive tebuconazole extraction from fruit juice and water samples using micro-solid phase extraction-HPLC-DAD

Tebuconazole (TBZ) is a widely used triazole fungicide that poses potential risks to human health and the environment due to its persistence in food and water. Effective monitoring of TBZ residues is crucial for ensuring food safety and environmental protection. This study presents a novel method for synthesizing Ni/Co-MOF@Co3O4 nanoflowers (NFs) and their application in extracting TBZ from water and fruit juice samples via micro-solid phase extraction (µ-SPE). Ni/Co-MOF@Co3O4 NFs was synthesized using the hydrothermal technique followed by calcination. The synthesized nanoflowers were characterized through SEM, XRD, and FT-IR analyses. Optimal extraction conditions were established at pH 8, using 10 mg of adsorbent, with adsorption and desorption times of 3 and 2 min, respectively. TBZ analysis was conducted using HPLC with a Poroshell 120 EC-C18 column and a diode array detector (DAD). The method demonstrates excellent recovery rates (90–102 %) and RSD% of 3.7 % in spiked fruit juice and natural water samples. The analytical performance showed a wide linear range (1–2000 µg L−1) with a high correlation coefficient (R2 = 0.9998), a detection limit of 4.0 ng L−1, and a quantification limit of 13.0 ng L−1. This approach is fast, simple, and highly sensitive, offering a reliable technique for detecting trace levels of TBZ in food and water environments.

Identifying toxic elements in water, sediments, and roots of mangrove forest (Avicennia marina) in Chabahar Bay, Sea of Oman

Mangroves play a crucial role in filtering pollutants from water and sediments. However, excessive accumulation of potentially toxic elements (PTEs) has harmful effects on marine organisms. This article investigates the concentration and distribution of PTEs in water, sediment, and the roots of endangered mangrove species in Chabahar Bay, a subtropical coastal wetland. The relationship between PTE absorption and accumulation rates with flow rate, mangrove extent, and sedimentation was also explored. Water, sediments, and aerial roots samples were taken at four stations along the wetland from upstream fresh water toward outfall. According to the results, Cd had more distribution in sediment and water samples and plants did not play as adsorbent in the study area. The lowest and highest PTEs concentrations were detected in water and sediment media, respectively. The average concentrations of PTEs in the sediments in the Chabahar Bay were Fe > Cr > Zn > Ni > Cu > Pb > Co > As > Cd while in aerial roots of the mangroves were Fe > Zn > Ni > Cr > Cu > Co > As > Pb > Cd. Except Zn, As, and Cd, there was a good correlation between increasing PTEs content in the sediments with decreasing flow velocity and increasing vegetation density along stations 3 to 4. In addition, the amount of PTEs uptake by the mangroves was less than that of global wetlands. The results also demonstrated a greater uptake in aerial roots in saline water for Cr, Ni and Co. Since the absorption rate of PTEs by the aerial roots of pneumatophores is slower than that in sediments, elevated concentrations of PTEs in the sediment can disrupt the entire ecosystem, leading to a potential decline in biodiversity. These toxins can enter the food chain, affecting not only organisms directly interacting with the sediment but also higher trophic levels, such as fish and birds.

Starch-modified nickel ferrite nanoparticles as a magnetic nano-bio adsorbent for the extraction and determination of lead in water and Moringa oleifera samples

In this work, nickel ferrite magnetic nanoparticles were synthesized using a facile hydrothermal method. The surface modification of the prepared nanoparticles was carried out using cross-linked starch as a good stabilizer and biopolymer. The as-prepared nickel ferrite-starch nano-bio composite was characterized using numerous techniques, and introduced as a novel adsorbent. The initial experimental results indicated that the adsorbent has a good capability to extract lead ions (Pb(II)) from aqueous solutions. Hence, the adsorbent was applied for dispersive magnetic solid-phase extraction of Pb(II) before flame atomic absorption spectrometric detection. Some variables affecting the extraction efficiency such as sample volume (250.0mL), pH (6.5), type and eluent concentration (0.3molL1 nitric acid), amount of the adsorbent (200mg), extraction time (15min), and desorption time (15min) were investigated and optimized. Moreover, the adsorption capacity (35.50mgg1), stability and reusability (80 extraction/desorption cycles), and selectivity of the adsorbent towards the analyte were studied. In the optimized conditions, the linear dynamic range of the constructed calibration graph is between 0.5 and 140.0ngmL1. The limit of detection and limit of quantification of the method are 0.12 and 0.40ngmL1, respectively. The average intra-day and inter-day relative standard deviations (for n=6 and 5.0, 50.0 and 100.0ngmL1 Pb(II) concentration) are 2.02% and 3.72%, respectively. To validate the method, the certified reference material NIST SRM 1643e was analyzed, and the method was used for the pre-concentration and determination of lead ions in different sections of Moringa oleifera medicinal plant and several water samples. The acceptable relative recovery values between 98.0 and 102.7% were attained for the spiked samples, approving the ignorable matrix effect of the method.

A three-dimensional nitrogen-rich conjugated microporous polymer for solid-phase microextraction of nitroaromatic compounds from environmental water and soil samples

Nitroaromatic compounds (NACs), as a kind of important chemical intermediates, are widely used in industrial productions. However, NACs have carcinogenic effect and their residues may pose harm to human health. Therefore, there is necessity to set up effective analytical method to monitor them in some environmental samples. However, because of their low concentrations in real samples, they need to be enriched by an effective adsorbent before the subsequent instrumental detection. In this work, a three-dimensional nitrogen-rich conjugated microporous polymer (DCT-Try-CMP) was synthesized with 3,6-dichloro-1,2,4,5-tetrazine and triptycene as monomers via Friedel-Crafts reaction. It presented a good adsorption capability for the NACs. After optimization, a solid-phase microextraction with DCT-Try-CMP fiber combined with gas chromatography-flame ionization detection for the quantitation of trace NACs in environmental water and soil samples was developed. The limits of detection of the method (S/N = 3) for environmental water and soil samples were 0.08–0.30 μg L-1 and 1.00–5.00 ng g-1, and the limits of quantification (S/N = 9) were 0.27–0.90 μg L-1 and 3.00–15.0 ng g-1, respectively. The linear quantification response ranges for the analytes were 0.27–200 μg L-1 and 3.00–1000 ng g-1 for water and soil samples, respectively. For water samples at the analytes concentrations of 5.00, 50.0 and 100 μg L-1, the method recoveries ranged from 82.2% to 120% and for soil samples at the concentrations of 15.0, 200 and 400 ng g-1, the method recoveries fell in the range from 80.2% to 120%. The method provides a sensitive and effective approach for monitoring trace NACs in environmental water and soil samples.

Radiometric hazard assessment of soil and water samples adjacent to Bangladesh's first nuclear power plant before commissioning: Insights into human health and environmental radiological dynamics

The current study provides a comprehensive examination of both natural and anthropogenic activity concentrations found in soil and surface water samples near the Rooppur nuclear power plant (RNPP), the first of its kind under construction in Bangladesh. The investigation covers a range of activity concentrations including 226Ra, 232Th, and 40K in fifty soil and fifty water samples, revealing values ranging from 18 to 38, 18–51, and 310–560 Bqkg−1 for soil, and 2.1–6.1, 2.1–5.5, and 67–115 Bqkg−1 for water, respectively. Although outdoor absorbed dose rate, outdoor effective dose, and gamma representative level index values in some soil samples exceed global averages, other radiological hazard parameters such as radium equivalent activity, annual effective dose, external and internal hazard indices, and lifetime carcinogenic risk for both soil and water samples consistently remain below safety thresholds established by international organizations. These findings indicate that the soil and water samples collected from the vicinity of the RNPP do not pose significant radiological hazards to the nearby populations. This study's comprehensive dataset is anticipated to play a crucial role in facilitating the identification and evaluation of any changes in environmental radioactivity, thereby assisting in the effective management and regulation of nuclear power plant activities in the years to come.

Persistent luminescent nanoparticles with enhanced afterglow through polydopamine modification for separation-free and visual detection of iron ions in water

Fluorescence analysis is one of the most popular methods in metal ions detection, but the background interference is an unavoidable obstacle in the fluorescence analysis of complex samples. In this work, a persistent luminescence nanoprobe was designed to detect iron ions in real samples by avoiding background interference. First, the Sr4Al14O25:Eu2+, Dy3+ persistent luminescent nanoparticles (PLNPs) were prepared by solid-state reaction protocols and polydopamine (PDA) encapsulation. After modification, these PLNPs@PDA showed better afterglow performance. More importantly, the PLNPs@PDA are highly selective toward iron ions, and could serve as an afterglow “turn off” nanoprobe for selective detection of iron ions through a dynamic quenching mechanism, with a detection limit of 2.86 μM. To further realize rapid and on-site detection, a test strip based on PLNPs@PDA was prepared and applied, which also showed good detection performance in real water samples. Compared with other detection methods, this afterglow imaging detection does not depend on expensive instruments, and can effectively shield the interference of background fluorescence from complex water samples, which has a good application prospects in the actual water sample. This work opens a new avenue for developing afterglow probe for the detection of metal ion in water samples without background interference.

In-bottle thin film solid phase microextraction coupled to flow modulated comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry for monitoring of organic pollutants in environmental waters

The monitoring of organic compounds in water is critical for assessing environmental health and the effectiveness of treatment processes. In this study, we present a robust and eco-friendly approach to environmental water analysis that integrates thin film solid phase microextraction (TF-SPME) with comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GC × GC-TOFMS). This method is designed to detect multiclass organic pollutants in environmental water, thus enabling applications such as detailed analyses of changes post-treatment processes. The supervised PCA results revealed distinct clustering of the three water sample classes - raw wastewater, outflow from WWTF, and river water - each occupying separate regions in the principal component space. Several organohalogen compounds were identified as key differentiators among the water samples, highlighting significant compositional differences across the analyzed classes. Notably, an increased abundance of certain chlorinated compounds was observed in raw wastewater before it underwent purification treatment at the WWTF. Additionally, the greenness evaluation of the in-bottle TF-SPME-GC × GC-TOFMS indicated whiteness scores of 96.7% for the in-bottle TF-SPME-GC × GC-TOFMS method and 79.0% for the LLE (US EPA 8270)-GC/MS method. This approach facilitates the identification of a wide array of organic compounds, characterized by diverse physicochemical properties, through their mass spectral profiles. We applied this method to various environmental water samples, including raw wastewater, effluent from wastewater treatment facilities, and river water, to assess the impact of treatment processes on organic pollutant levels. Our developed strategy effectively monitored alterations in several organic compounds within these environmental water samples. Our results demonstrate that TF-SPME coupled with GC × GC-TOFMS proves to be both straightforward and comparable in performance to other methods for analyzing low-level organic pollutants in water samples, making it a valuable tool for environmental monitoring and discovering new emerging contaminates.

Biomonitoring emerging hazards of pharmaceuticals in river water using gut microbiome and behavioural Daphnia magna responses

A cost-effective Daphnia magna testing framework was applied to identify emerging hazards such as neurological and cardiovascular defects as well as antibiotic resistant genes (ARGs), related to pharmaceuticals present in waste water treated (WWTP) effluent discharged into rivers. D. magna juveniles were exposed during 48 h to water samples from three rivers in the vicinity of Barcelona (NE Spain), Besós, Llobregat and Onyar, upstream and downstream of WWTP discharging points. The analyses included measuring levels of 80 pharmaceutical residues in water samples by HPLC-MS, determination of the loads of different clinically relevant antibiotic resistant genes (ARGs) in both water samples and exposed animals, and assessment of toxic effects in feeding, heartbeat responses, and behavioural indicators. ARG prevalence in water, but not in gut microbiomes, was associated with the presence of bactericides in water. These results suggest that their levels were high enough to put a selective pressure over river microbial populations, but that Daphnia guts were not easily populated by environmental bacteria. Toxic effects were found in 20 to 43% of water samples, depending on the river, and related to water quality parameters and to pollutant levels. For example, heartbeats were correlated with salinity, whereas feeding impairment did so with high loads of suspended solids. In contrast, behavioural alterations were associated to the concentration of neuroactive chemicals. Accordingly, we hypothesize that measured neuroactive chemicals have caused the observed effects. If this also applies to local invertebrate populations, the environmental consequences may be severe and unpredictable.

Exploration of supramolecular solvent-based microextraction for crystal violet detecting in water samples

This approach highlights the advantages of supramolecular solvents in a new microextraction model. The distinct properties and behavior of this supramolecular solvent provide enhanced extraction capabilities for detecting crystal violet (CV) in water samples. The methodical experimentation was executed to optimize the critical process parameters, providing maximum efficiency of crystal violet extraction at optimal conditions with pH set at 2.7, 186 μL of extraction solvent, extraction time of 3.5 min, and a salt amount of 3.1 % w/v, yielding the best results. Analytical data from extraction experiments under these optimal conditions demonstrated a high extraction percentage. The extraction model exhibited a linear response within the range of 10–800 ng mL−1 of crystal violet, with a detection limit of 2 ng mL−1. This model enables the measurement of CV in water samples with recovery rates exceeding 97 %, offering a straightforward and accessible approach for analysis.

Hydrothermally synthesis of a green SnS-Carbon microplate adsorbent for the removal of mercury ion from water samples

Mercury ion (Hg2+) finds a broad industrial application and due to its significant toxicity to both humans and aquatic life, development of highly effective adsorbents for its removal holds considerable importance. This study introduces a green adsorbent consisting of tin sulfide (SnS)‑carbon microplates synthesized through a straightforward one-step hydrothermal process followed by its application for the removal of Hg2+ from water samples. The synthesized adsorbent is characterized using Fourier Transform Infrared Spectrophotometry (FT-IR), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray spectroscopy (EDX), Thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) and X-Ray diffraction analysis (XRD). Through the optimization of crucial parameters and with thanks to the effective interaction between S atoms (soft base) of SnS-C adsorbent and Hg2+ (soft acid), an impressive Hg2+ removal percentage of approximately 99.0 % is achieved for 100 mg L−1 Hg2+. Interpreting of isotherm models indicate that Hg2+ adsorption conforms to the Langmuir isotherm with a maximum adsorption capacity of 238.1 mg/g. Finally, the SnS-Carbon microplate adsorbent exhibits notable advantages, including a green and convenient synthesis route (achieved through a one-step hydrothermal method) and high efficiency, making it a potent adsorbent for the decontamination of Hg2+ from water samples.

Chitosan-based emulsive liquid-liquid microextraction for the determination of strobilurin fungicides in water samples

Strobilurin fungicides are widely used pesticides globally; however, their residues pose a risk to environmental safety and human health. This study aimed to develop a rapid and green method for detecting strobilurin fungicide residues. Chitosan and magnetic deep eutectic solvent-based emulsive liquid-liquid microextraction method combined with high-performance liquid chromatography was developed to determine strobilurin fungicides in water samples. A high-concentration oil-in-water emulsion containing chitosan solution and extractant was formulated, followed by the addition of samples to form a low-concentration oil-in-water emulsion to complete the rapid pretreatment, therefore solving the limitation of emulsive liquid-liquid microextraction in the inapplicability of extractants. Traditional microextraction required toxic solvents and complex equipment to facilitate the dispersion of extractants, whereas this study used only chitosan solution to aid in emulsifying extractants. The new green magnetic deep eutectic solvent synthesized by tetraoctylammonium bromide, ferric chloride, and oleic acid was used instead of toxic extractants. An external magnetic field assisted the extractant phase collection, which shortened the separation time. Under optimal conditions, the recovery of this method was 83.3 %–107.4 %, the limit of detection was 0.0010–0.0021 mg L−1, and the coefficient of determination was >0.994. This rapid, green, simple, and efficient chitosan-based microextraction method could detect strobilurin fungicide residues in water samples because of its enhanced compatibility with hydrophobicity extractants.

UV-light fluorescence as a confirmation method for presumptive Legionella colonies isolated from water samples.

Legionnaires' disease (LD) is a severe and potentially fatal form of bacterial pneumonia caused by Legionella spp. We evaluated the use of UV-light for detecting Legionella non-pneumophila in water samples according to the NEN-EN-ISO 11731:2017 methodology (reference method) in a collaborative effort involving 10 laboratories. First, a test panel was constructed of 298 strains: 157 Legionella strains and 141 non-Legionella strains were cultured on buffered charcoal yeast extract (BCYE)-medium and confirmed according to ISO 11731: 2017 (cultured on BCYE agar plates with and without l-cysteine), and by matrix-assisted laser desorption-ionization time of flight or next generation sequencing. All strains were additionally exposed to an UV-light to assess if they showed a bright blue fluorescence effect (UV-positive) or not (UV-negative). Second, in an interlaboratory study, 10 laboratories analyzed a blinded set of 16 Legionella strains and 8 non-Legionella strains using both methods. The test panel analyses showed 100% accordance between the UV-light and reference method. In addition, the interlaboratory study results showed full agreement between both methods. Our results support the implementation of UV-light detection to confirm Legionella presumptive colonies during analyses of water samples according to the NEN-EN-ISO 11731:2017 methodology. Implementation of UV-light confirmation could reduce workload, time-to-result and costs for the analyses of water samples for the presence of Legionella.

Evaluation of groundwater in the city of Sousse in eastern Libya for some heavy metals and nitrate ions

Evaluation of groundwater potential and its quality assessment for irrigation has recently become a major concern, especially in developing countries due to various constraints. The aim of this study is to evaluate the quality of groundwater and establish whether they are safe for irrigation usage in Sousa city, Libya. The aim of the study to evaluating of groundwater polluted with Lead, Cadmium and Chromium metals and nitrates ions. Five water samples were collected from different wells were and analyzed. For understanding the hydro chemical and polluted characteristic with some heavy metal as (Pb, Cd and Cr ) respectively, and the suitability for irrigation purposes. Nine parameters were considered for calculating the irrigation water quality indices which are pH , electrical conductivity (EC), ions ( cations and anions) such as Calcium, magnesium, potassium sodium, chloride ,bicarbonate, sulphate,, in addition to some calculated parameters for as SAR, Adj. SAR, RSC, TDS and pHc, furthermore some heavy metals and nitrates ions were investigated. The results of polluted with heavy metals and nitrate ion, showed that the most water samples did not exceed the maximum limit according to FAO and Libyan local standard, except W05 exceeding the permissible limit for lead and nitrate ion, and W02 for pb. The results of this study emphasis that routine monitoring of groundwater play a vital role in maintaining its quality and serve as guideline for sustainable management of water quality in region study. Keywords: irrigation water, heavy metals, nitrate, ground water.