Contaminated Water Samples Research Articles

All in one transitional flow-based integrated self-powered catechol sensor using BiFeO3 nanoparticles

A highly reliable transitional flow-based integrated self-powered catechol sensor (SPCS) proposed for the detection of organic contaminants in water samples. Here the cost-effective hollow tube-shaped piezoelectric nanogenerator (TFPNG-SPCS) by the BiFeO3 nanoparticles works as an SPCS. The obtained ferroelectric remnant polarization and coercive voltages are 0.089 μC/cm2 and 223 V at 1 Hz frequency. The TFPNG device delivers an instantaneous peak-to-peak power density of 2.624 mW/m2 at 500 MΩ. The classification between physical and chemical stimuli is possible through in-tunnel transitional flow and converts them into a readable electrical signal. The proposed TFPNG-SPCS sensor has good selectivity, reasonable sensitivity, eco-friendly, and detection limits down to 10.2 μM, having a linear relationship with catechol concentrations.

Optimization of Culture Protocols to Isolate Leptospira spp. from Environmental Water, Field Investigation, and Identification of Factors Associated with the Presence of Leptospira spp. in the Environment.

The successful culture of Leptospira spp. from the environment is challenging. Here, we optimized the isolation of Leptospira spp. from water samples spiked with different species and initial concentrations of this organism. The time periods between water sampling and the isolation process were varied (0, 2, and 4 weeks). Bacterial cultures were observed under a microscope, and cultures were graded for cell density, weekly, for 12 weeks. Most pathogenic Leptospira spp. were difficult to culture under all conditions. All conditions of water samples spiked with novel species of Leptospira subclade P1 were culture positive within 2 weeks. For Leptospira subclade P2, storing samples for 2 weeks prior to isolation resulted in more successful isolation compared with isolation after other storage conditions. For subclade S1, all samples with initial bacterial concentrations of more than 103 colonies/mL, under all storage conditions, were successfully cultured. These results suggest that storing contaminated water samples for 2 to 4 weeks in the dark at an ambient temperature prior to culturing can improve the isolation of Leptospira spp. from the samples. We implemented this protocol and collected water samples from natural sources accessed by both humans and animals. Leptospira spp. was identified in 32% (35/109) of water samples. The animal species using a water source influenced the likelihood of water samples being contaminated with Leptospira spp. Cultures of Leptospira spp. from environmental samples can provide useful information for understanding the complex interactions between humans, animals and the environment in the transmission of leptospirosis.

Comparative Insight into the Performance of Two Different Amine‐Functionalized CNTs for the Chemical Speciation of Chromium

AbstractPersistent industrial activities have led to an increase in the chromium content in environmental water bodies. The accurate quantification of trace chromium species such as Cr(III) and Cr(VI) is crucial as Cr(VI) can exhibit toxicity even at sub‐ppb levels. We report herein a comparative chromium speciation study using two chemically functionalized nanoadsorbents and determination with hyphenated flow injection‐flame atomic absorption spectrometry (FI‐FAAS). The most efficient preconcentration performance was obtained by optimizing the chemical and hydrodynamic parameters. Cr(VI) concentration was ascertained by the reduction to Cr(III) as the nanoadsorbents were selective for Cr(III) adsorption only; thus, speciation was achieved. The method was selective for Cr(III) in the presence of interfering matrix components. Preconcentration factor >90 and detection limit <0.11 μg L−1 were obtained for both the nanoadsorbents (%RSD∼1.0 %). The adsorption capacity of CNT‐TYR and CNT‐ASA was found to be 42.0 and 43.2 mg g−1, respectively. The application of the proposed method to contaminated water samples gave recoveries >95 %. The accuracy of the method was verified using NIST SRM 1640a.

Application of bar adsorptive microextraction (BAµE) for the determination of pesticides and emerging contaminants in water used for rice cultivation in southern Brazil

Brazil is among the ten largest rice producers in the world, concentrating its production in the southern region. Anthropic activities, such as the disposal of chemicals in the ecosystem and consequently in the aquatic environment, end up harming the availability and quality of the water. Here, we developed an analytical method based on BAµE with WAX as an extraction phase for the determination of 5 pesticides and 2 emerging contaminants in water samples used in rice cultivation by HPLC–DAD. The method was fully optimized through univariate and multivariate approaches. The optimized condition was obtained with 145 min of extraction time, without salt addition and 35 min of desorption time using 250 μL of MeOH:AcEt (60:40, v/v). A reduced mass of extraction phase (around 4 mg) and sample and solvent volumes (15 mL and 300 µL, respectively) were used. The bars have a low cost and can be used up to 20 times without loss of extraction efficiency. Furthermore, the developed method presented high-throughput, because it uses a Voltage Regulator Variac system that allows the coupling of six magnetic stirrers simultaneously. The LODs ranged from 1.67 to 2.50 µg L−1 and the LOQs ranged from 5.00 to 7.50 µg L−1; both were below the VMP established by Ordinance 2.914/2011/MS for drinking water. Relative recoveries applied to the sample ranged from 80 to 121%. The intra-day and inter-day precision were up to 14% and 19%, respectively. The results were satisfactory, in accordance with the validation guidelines of the AOAC. Twenty-four samples collected in the Camboriu River Basin, which is influenced by rhiziculture, were analyzed and the analytes were not detected, as they are below the limits obtained in this method.

Magnetotactic curcumin iButtonbots as efficient bactericidal agents

The microbial contamination of drinking water is one of the most major concerns of community health in the developing world. Numerous water-borne pathogens are rapidly evolving and becoming resistant to traditional antibiotics. To get an efficacious bactericidal response, an assembly of several antibiotics or increased dosage are being administered, which may produce adverse side effects after prolonged use. Here, we describe a proficient method for disinfecting water-borne coliform bacterial strains of Escherichia coli DH5 $$\upalpha $$ from contaminated water samples using magnetic microbots decorated with curcumin (CU) conjugates. These magnetic microbots, namely, iButtonbots were composed of soft Agaricus bisporus (button mushroom) microcapsules with inherit antimicrobial properties. The locomotives were coated with magnetite nanoparticles for their remote guidance towards cells and collection along with CU for more enhanced bactericidal response. CU, a major active constituent of the Indian dietary spice turmeric and edible button mushrooms are known to exhibit antimicrobial activity against a wide range of bacterial species. The synergic antibacterial effect of CU and mushroom constituents, imparts a profound bactericidal property to these magnetic microbots. We have demonstrated that microbots are capable of efficiently killing majority of bacterial cells in contaminated water samples. After extermination of bacteria, magnetic properties of embedded magnetite nanoparticles in porous mushroom matrix, allows collection of microbots from water samples. The presented biocompatible microbots offer an innovative method for rapid decontamination of bacteria-laden drinking water samples.

A highly selective novel multiple amide based Schiff base optical chemosensor for rapid detection of Cu2+ and its applications in real sample analysis, molecular logic gate and smart phone

A novel multiple amide based Schiff base chemosensor L has been designed rationally for selective colorimetric detection of Cu2+ ion in CH3OHH2O (1:1 v/v, tris HCl buffer 10 µM, pH = 7.2) solution. The colour change (colourless to yellow) is so prominent to be visible in bare eye. From the absorption titration, job's plot measurement and ESI-MS revealed that receptor-analyte binding occurs in a 2:1 fashion and the binding sites were confirmed by the X-ray single crystal structure of host-guest complex. Solvent dependent crystal structure from a homoleptic monomer to 2D polymer was observed. The detection limit was found to be 1.8 µM with the association constant value 1.3 × 102 M−1/2 which is highly desirable for 2:1 complexes. The chemosensor L has been applied for construction of binary logical device, recovery of contaminated water samples and smart-phone based analysis.

Removal of phosphate and nitrate ions from water by amine crosslinked magnetic banana bract activated carbon and its physicochemical performance

In the present work, magnetic separation is one of the most effective techniques to recovering the phosphate and nitrate ions from water using amine crosslinked magnetic banana bract activated carbon (ACM@BBAC) was prepared via magnetization and was further crosslinked by amine groups. The ACM@BBAC was extensively studied by using SEM, EDAX with mapping images, FTIR, TGA-DSC, XRD, BET, and VSM analytical techniques. The effect of various influencing parameters, i.e. adsorbent dosage, shaking time, solution pH, co-existing anions and temperature were assessed. The adsorption statics were performed by Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. Reaction and diffusion-based kinetic models were used to find the kinetic factors such as correlation coefficients, rate constants and standard deviations for each kinetic models and were also discussed. Thermodynamic parameters such as ΔG, ΔS° and ΔH° have been calculated and it could be well described for the adsorption reaction was endothermic and spontaneous in nature. Phosphate and nitrate adsorption mechanisms predominately involved by electrostatic force of interaction, ion-exchange and surface complexation with ACM@BBAC. The suitability of the ACM@BBAC at environmental condition was inspected with contaminated water sample collected from nearby eutrophic endemic area. The as-prepared ACM@BBAC is an effective adsorbent for the remediation of phosphate and nitrate ions from water/ wastewater.

Study of Metal Ion Removal from Aqueous Systems Using Magnetic Nanostructures Based on Functionalized Poly(Benzofuran-co-Arylacetic Acid)

Metal pollution has become a worldwide problem, mainly because of the toxicity, effects on living organisms, and the impact on the food chain and the quality of drinking water. Researchers have been focusing on developing new materials through green chemistry methods in order to remove these pollutants from the environment. In the recent decades, due to their unique properties, magnetic nanostructures containing functionalized polymers as shells have been demonstrated to be useful in water and wastewater treatment for this application. In this study, we report the synthesis and characterization of hybrid magnetic core-shell nanostructures including magnetite as the inorganic core and poly(benzofuran-co-arylacetic acid) functionalized with Nα, Nα’–bis(carboxymethyl)-L-lysine as the organic shell. These nanomaterials were used in the adsorption of different metal ions from aqueous solutions and contaminated water samples collected from Roșia River (Roșia Montană, Romania), representing attractive alternatives for water and/or wastewater treatment. The properties of the magnetic hybrid nanostructures were investigated by Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), magnetization measurements. The heavy metal concentrations in aqueous solutions were determined by flame atomic absorption spectrometry (FAAS).

Graphene oxide functionalized with a Schiff Base for the removal of Pb(II) ions from contaminated water: experimental and modeling approach

AbstractBACKGROUNDThe current study suggests an experimental and modeling approach for the adsorptive removal of lead(II) ions from contaminated water sample. The Schiff base reagent, bis(salicylaldehyde)ethylenediimine (Salen) functionalized graphene oxide (GO) was applied as adsorbent. Salen functionalized GO was prepared and characterized using scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDX), X‐ray diffraction (XRD), Fourier‐transform infrared (FTIR) spectroscopy, zeta potential and dynamic light scattering (DLS) techniques. The batch experiment represented maximum removal efficiency of 99% at pH 6.5, adsorbent dose of 100 mg L−1 and 5 min contact time.RESULTSThe residual concentration of lead(II) after removal was measured using flame atomic absorption spectrometry. DLS results suggested slightly smaller particle size of Salen modified GO than pristine GO. The optimized model calculated with Gaussian 09 W software showed maximum total energy (1.3959 eV) and dipole moment (6.8646 D) for model of lead interaction with Salen–GO. The Langmuir adsorption isotherm model was most fitted and the kinetic data indicated that the lead(II) adsorption on Salen–GO followed second‐order model. The maximum adsorption capacity calculated was 68 mg g−1.CONCLUSIONThe adsorbent was applied to remove lead(II) ions in real contaminated water samples of the battery manufacturing industry with average removal of 95% with relative standard deviation 1.23% (n = 3). The adsorbent was reusable with desorption of lead(II) from adsorbent and was 95% with 0.2 mol L‐1 nitric acid. © 2020 Society of Chemical Industry

Colorimetric and smartphone-integrated paper device for on-site determination of arsenic (III) using sucrose modified gold nanoparticles as a nanoprobe.

An optical colorimetric and smartphone-integrated paper device (SIPD) is demonstrated for determination of As (III) in water and soil samples using sucrose modified gold nanoparticles (AuNPs/Suc) as a nanoprobe. The mechanism for determination of As(III) is experimentally validated by performing UV-Vis, transmission electron microscope (TEM), Fourier transforms infra-red spectroscopy (FTIR) and dynamic light scattering (DLS) measurements. The density function theory (DFT) calculations using B3LYP with 6-311G (2d,2p) and LANL2DZ basis sets is used to theoretically prove the mechanism for determination of As(III). In addition, the paper fabricated with AuNPs/SuC was used as a nanoprobe for quantitative determination of As(III) using smartphone and ImageJ software. Calibration plot was linear over 10-800 μgL-1 for colorimetric determination of As(III) with limit of detection (LOD) of 4 μgL-1 acquired when the absorbance ratio obtained at 594nm/515nm. The linearity range of 50-3000 μgL-1 with LOD of 20 μgL-1 was determined using smartphone-integrated paper device. AuNPs/Suc is successfully employed for determination of As (III) from contaminated water and soil samples in colorimetry and SIPD. Graphical abstractColorimetric and Smartphone-integrated paper device used for selective detection of arsenic from contaminated water samples using sucrose modified gold nanoparticles (AuNPs/Suc) as a sensing probe.

A Novel Approach for Indexing Heavy Metals Pollution to Assess Groundwater Quality for Drinking Purposes

The present study proposes a new approach for indexing heavy metals ions to examine groundwater quality in North Kurdufan Province, Sudan. The new approach is developed based on the most frequently used methods for indexing heavy metals pollution in water. It is created in order to avoid the weaknesses of the current indexing systems. As per the new indexing approach, heavy metal contamination in water samples is evaluated by two types of indices: the negative evaluation index (NEI) and positive evaluation index (PEI). The water worthiness is assessed based on a pair of indices, NEI and PEI. Water quality increases with the decrease of PEI and NEI values. NEI indicates the contribution of heavy metals with a concentration not exceeding the highest desirable limit () in the water sample, while vice versa regarding the PEI. If all heavy metals concentrations in the water sample do not exceed , the sum of NEI should be less than zero, but not less than −100, implying that the sum of PEI will be zero. When all heavy metals concentration exceeds , the sum of NEI should be equal to zero, and PEI will be greater than zero. The results of the newly proposed approach have been discussed and compared with the existing indexing methods as regards to the best and worst samples. The spatial distribution of NEI and PEI are in complete agreement with the metals spatial distribution. The comparison result showed that the new index is robust, with fair calculations, and gives the best classification of groundwater quality.

Study on the Purification of TN in Different Concentration Waters by Artificial Floating Bed

The artificial floating bed reduces the nitrogen, phosphorus and organic pollutants in the water by the absorption of the roots of the plants, thereby purifying the biological control of water quality. In this paper, by using four different concentrations of contaminated water samples, the static test of Ipomoea aquatica. was carried out on a floating bed. The growth characteristics and main water quality indexes of the plants were measured at intervals of 10 days. The experimental period was 60 days, and the amaranth was quantitatively analyzed. The purification law of TN in water samples with different concentrations was analyzed, and the dynamic changes of nutrients in different tested water samples were analyzed, and the purification equation was constructed. The results showed that the floating bed cultivation of leek can absorb, adsorb and degrade the nitrogen in the water sample, carry out metabolic activities, and synthesize the substances needed by itself, which is closely related to the growth, and the TN concentration and the growth time of the plant are significantly negative.

Microwave-assisted adsorption of Cr(VI), Cd(II) and Pb(II) in presence of magnetic graphene oxide-covalently functionalized-tryptophan nanocomposite

Microwave (MW)-assisted remediation of heavy metals toxicity using a powerful environmental-friendly nanocomposite of magnetic graphene oxide functionalized tryptophan (MGO-Trp) was explored in this work. Magnetization of GO with Fe3O4 nanoparticles prepared in situ was uniformly achieved and then covalently bonded to Trp. The structural characterizations and thermal stability of synthetic MGO-Trp nanocomposite were investigated by FT-IR, XRD and TGA. A homogenous flake-like surface of well magnetized GO sheets was manifested by SEM and TEM images. The surface area measurements and BET method (adsorption/desorption curve) indicated a surface area = 10.157 m2 g−1 and mean pore diameter = 13.229 nm. MW-technique and MGO-Trp nanocomposite declared an efficacious sorption of Pb(II), Cd(II) and Cr(VI) ions with high adsorption capacity values. Different factors, MW-contact time, temperature, pH, nanocomposite dose and metal concentration affecting on the adsorption capacity, were followed up. The highest values of adsorptive capacities of Pb(II) and Cd(II) were observed to be 4800 and 5400 μmol g−1, respectively at pH 7 and MW-contact time of only 20s. The Cr(VI) species were efficiently extracted at pH 2 with capacity values = 3400 μmol g−1. Kinetic studies brought to light that the adsorption system was agreeing with pseudo-second order and Elovich than either pseudo-first order or intraparticle diffusion models. Thermodynamic parameters (ΔH°, ΔS° and ΔG°) were also evaluated and provided spontaneous exothermic adsorption for both Pb(II) and Cd(II) ions, while spontaneous endothermic adsorption behavior was observed for Cr(VI) species. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D-R) models and their parameters were investigated, confirming favorable and rapid adsorption processes. The potential applications of MGO-Trp as a felicitous and high performance nanocomposite of the mentioned metal ions in presence of other competing ions as well as from naturally contaminated water samples were successfully accomplished in fast effective operations with extraction percentages close to 100%.

Combined experimental and theoretical studies on a phenyl thiadiazole-based novel turn-on fluorescent colorimetric Schiff base chemosensor for the selective and sensitive detection of Al3+

A phenyl thiadiazole based receptor (L) has been presented for fluorescent colorimetric detection of Al3+ion with very low detection limit in aqueous medium. The probeLcan be applied for logic gate formation, recovery of contaminated water samples and smart-phone based analysis.

Hierarchically porous BiOCl@NiCo2O4 nanoplates as low-cost and highly efficient catalysts for the discoloration of organic contaminants in aqueous media

BiOCl@NiCo2O4 exhibits remarkable catalytic activity and stability and can be used to deal with real contaminated water samples.

Detection of <i>Legionellae pneumophila</i> in Waters by Culture and Polymerase Chain Reaction

Legionella pneumophila (L. pneumophila) is the most common causative agents for all outbreaks of Legionnaires’ disease. Prevention and control of Legionellosis requires surveying and monitoring of Legionella in the environment using conventional and modern technologies. The present study aims to compare detection of L. pneumophila in water samples using both culture and PCR techniques. A pre-enriched contaminated water sample was split into 13 subsamples. Culture and PCR tests were done from the subsamples after different intervals. The results showed a positive PCR result for L. pneumophila after 8 h of incubation. Also, L. pneumophila was detected by culture on non-selective BCYNE agar and selective GPVC agar after 5 and 6 days of incubation respectively. There was no significant difference between the non-selective BCYE- and the selective GVPC method. The PCR procedure was found more sensitive and differed significantly from the conventional selective GVPC method in isolation of L. pneumophila from water samples. It was concluded that pre-enrichment incubation allows the detection of L. pneumophila by PCR within a maximum of 12 h from the collection of water samples.

ATP MONITORING AS AN EXPRESS METHOD TO DETERMINE OBJECT CONTAMINATION

The article presents the results of indication of water and surface contamination. The researches were aimed at estimation of water safety and sanitary-hygienic condition of surfaces. To study the contamination of water samples and common surfaces, we used the traditional method and the bioluminescence-based express method. The bioluminescence method is based on determining the total amount of ATP (bacterial, somatic and extracellular) on contact surfaces and in water. The level of ATP (adenosine triphosphate) was determined using the Lumitester PD-30 (Kikkoman, Japan) luminometer device according to the manufacturer's instructions, using special test systems. The ATP bioluminescence method is commercially more available for simple and quick monitoring of the sanitary-hygienic control effectiveness according to the HACCP principles or international requirements. The traditional method of determining water (and other material) contamination was performed by inoculating water or surface wiping on a common nutrient medium and further cultivation under appropriate conditions. The strongest glowing reaction was observed in sea water, which can be explained by the presence of organic substances in it, while the bioluminescence values in potable (bottled) and filtered water tests were most close to control test. The results of testing the sanitary-hygienic condition of surfaces showed that the amount of adenosine triphosphate exceeded the limits in almost all tested objects. However, a slight exceeding of adenosine triphosphate level was observed on the internal surface of new (plastic) food containers. The investigations performed show that the bioluminescence-based express method can be used as a primary control that gives immediate information about the contamination of both surfaces and liquids. Using the bioluminescence method can shorten the time of the study and therefore reduce the cost of the test. However, when determination of qualitative and quantitative composition of the tested object’s microbiota is necessary, then the classical microbiological control must be performed.

Design of a Smart System for Rapid Bacterial Test

In this article, we present our initial findings to support the design of an advanced field test to detect bacterial contamination in water samples. The system combines the use of image processing and neural networks to detect an early presence of bacterial activity. We present here a proof of concept with some tests results. Our initial findings are very promising and indicate detection of viable bacterial cells within a period of 2 h. To the authors’ knowledge this is the first attempt to quantify viable bacterial cells in a water sample using cell splitting. We also present a detailed design of the complete system that uses the time lapse images from a microscope to complete the design of a neural network based smart system.

A SMARTPHONE-BASED EARLY ALERT SYSTEM FOR SCREENING OF COLIFORM CONTAMINATION IN DRINKING WATER

We present a proof of concept for quick screening and alerting of coliform/E. coli contamination in water samples using a device attached to a smartphone. Current methods of coliform detection rely upon relatively expensive laboratory-based time consuming techniques which require trained manpower and take at least 24-48 hours. This waiting time prevents quick action and the consequences can be severe since the contaminated water may already have been consumed by then. Instead an unattended smartphone can continuously monitor the sample and send an alert as soon as contamination is detected. Smartphones, especially older or unused ones, fitted with a customized compact incubator and a sample holder, can be set to take photos of the sample (mixed with a selective growth medium) at regular intervals. An image analysis algorithm would analyze the photos and predict contamination as soon as it notices any increase in turbidity and/or change in color of the sample under observation due to bacterial growth. On detection of contamination, alerts can be immediately sent out to the concerned parties and intervention can be made without any potentially harmful delay. To test this concept we built a prototype for the detection of coliform/E. coli contamination in water samples. With the initial bacterial counts varying from 1-10 to >108 colony forming units (CFU) per 100 ml of water samples, all the results were produced within a turnaround time of 4 to 12 hours and found to be comparable with conventional microbiological methods which require 24-48 hours of incubation.

Geochemical and environmental health threat evaluation of heavy metals in groundwater of Asad Abad, Hamedan, Iran

Geochemical, heavy metals (HMs) distribution, and environmental health treat due to cadmium (Cd), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn) had been studied within the groundwater of Asad Abad, Hamedan, Iran. The order and average percentage (meq l−1) of cations and anions has been: Ca2+ (49.3) > Mg2+ (32.3) > Na+ (17.9) > K+ (0.5) and $${\text{HCO}}_{3}^{ - }$$ (62.7) > Cl− (28.0) > > SO42− (6.2) > $${\text{NO}}_{3}^{ - }$$ (3.1). The principal water types were: Ca-HCO3, Mg-HCO3, and Na-HCO3. In contrast to the background concentration (3.4 mg l−1) and threshold (13 mg l−1) of $${\text{NO}}_{3}^{ - }$$, 45 and 40 percentage of water samples confirmed higher concentrations, respectively. The mean concentration (μg l−1) of Cd, Cu, Fe, Ni, Pb and Zn has been 117.2, 29.3, 136.0, 91.9, 48.4 and 5.8, respectively, and as a consequence, the order of HMs was Fe > Cd > Ni > Pb > Cu > Zn. Heavy metals which include Cd, Pb and Ni (37%) of water samples exceeded permissible levels, while Cu, Fe (96.5%) and Zn had been observed to be inside permissible limits. Contamination factor calculated for all HMs confirmed that contamination in water samples varies mostly from low to mild contamination. Based on sum of the percentage of each HM in class 2, 3 and 4 (moderate, considerable and very high degree of contamination, respectively), the contribution of every HM in contamination degree turned into calculate and the order was: Pb (100%) > Zn (93%) > Cu (71%) > Fe (64%) > Cd (53%) > Ni (43%). The outcomes indicated that Cd posed a capability non-carcinogenic health risk to consumers in all sampling sites.