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An unprecedented and direct PS-MS (paper spray ionization mass spectrometry) method was proposed for the detection of native peptides, that is, glutathiones (GSHs), homoglutathiones (hGSHs), and phytochelatins (PCs), in basil (Ocimum basilicum L.) roots before and after cadmium exposure. The roots were submitted to cold maceration followed by sonication with formic acid as the extractor solvent for sample preparation. PS-MS was used to analyze such extracts in the positive mode, and the results allowed for the detection of several GSHs, hGSHs, and PCs. Some of these PCs were not distinguished in the control samples, that is, basil roots not exposed to cadmium. Other PCs were noticed in both types of roots, uncontaminated and cadmium-contaminated, but the intensities were higher in the former samples. Moreover, long-time exposure to cadmium stimulated the formation of some of these PCs and their cadmium complexes. The results, therefore, provided some crucial insights into the defense mechanism of plants against an external stress condition due to exposure to a toxic heavy metal. The present study represents a promising alternative to investigate other crucial physiological processes in plants submitted to assorted stress conditions., (© 2024 John Wiley & Sons Ltd.)

Broussonetia papyrifera is widely found in cadmium (Cd) contaminated areas, with an inherent enhanced flavonoids metabolism and inhibited lignin biosynthesis, colonized by lots of symbiotic fungi, such as arbuscular mycorrhizal fungi (AMF). However, the physiological and molecular mechanisms by which Rhizophagus irregularis, an AM fungus, regulates flavonoids and lignin in B. papyrifera under Cd stress remain unclear. Here, a pot experiment of B. papyrifera inoculated and non-inoculated with R. irregularis under Cd stress was carried out. We determined flavonoids and lignin concentrations in B. papyrifera roots by LC-MS and GC-MS, respectively, and measured the transcriptional levels of flavonoids- or lignin-related genes in B. papyrifera roots, aiming to ascertain the key components of flavonoids or lignin, and key genes regulated by R. irregularis in response to Cd stress. Without R. irregularis, the concentrations of eriodictyol, quercetin and myricetin were significantly increased under Cd stress. The concentrations of eriodictyol and genistein were significantly increased by R. irregularis, while the concentration of rutin was significantly decreased. Total lignin and lignin monomer had no alteration under Cd stress or with R. irregularis inoculation. As for flavonoids- or lignin-related genes, 26 genes were co-regulated by Cd stress and R. irregularis. Among these genes, BpC4H2, BpCHS8 and BpCHI5 were strongly positively associated with eriodictyol, indicating that these three genes participate in eriodictyol biosynthesis and were involved in R. irregularis assisting B. papyrifera to cope with Cd stress. This lays a foundation for further research revealing molecular mechanisms by which R. irregularis regulates flavonoids synthesis to enhance tolerance of B. papyrifera to Cd stress., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A colorimetric paper-based enzyme-coupled antimony tin oxide nanoparticle (ATONP) nanobiosensor for selective detection of Cd 2+ ions in clams and mussels is presented. Alkaline phosphatase (ALP) was immobilized on ATONPs via 16-phosphonohexadecanoic acid (16-PHA) to develop ATONP-ALP nanobiosensor. The biosensor was characterized using XPS, Raman spectroscopy, SEM, and EDX. ATONP-ALP nanobiosensor exhibited high selectivity towards detection of Cd 2+ ion with a LOD 0.006 μg L -1 and linear range of detection 0.005-1 μg L -1 . The developed biosensor was further integrated into a low-cost paper-based format. A visual color change was obtained for Cd 2+ ion in the range 0.1-10 μg L -1 . The developed biosensor was successfully demonstrated for the analysis of Cd 2+ ions in clams with recoveries 101-104%. The ATONP-ALP nanobiosensor was validated using mussel tissue (BCR-668) and the conventional ICP-OES and ICP-MS techniques.

Cd 2+ and Pb 2+ are two typical metallic pollutants in food. Therefore, it is of great significance to establish a method which can simultaneously detect them. Here, an electrochemical sensor was established to simultaneously detect Cd 2+ and Pb 2+ in food samples based on sensing electrode prepared by conductive carbon paper, rGO and CoZn·MOF (CP-rGO-CoZn·MOF). Under the optimized conditions, the proposed electrochemical sensor achieves simultaneous detection of Cd 2+ and Pb 2+ low to 0.565 nM (Cd 2+ ) and 0.588 nM (Pb 2+ ), respectively. Further selective experiments and repetitive experiments perform well. Spiked experiments find that the recovery rates of Cd 2+ and Pb 2+ in food samples are between 97.5% to 105.9% and 94.3%-109.6%, indicating the established electrochemical sensor owns a good response to the targets. Besides, relative standard deviations (RSD) of them are no more than 5.817%, showing its potential in practical applications., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Instrument-free, portable and direct read-out mini-devices have wider application prospects in various fields, especially for real-time/on-site detection in environmental science. Herein, a colorimetric fluorescent sensor for detecting cadmium ions (Cd 2+ ) based on aggregation-induced emission (AIE) was established, fluorescent paper strips integrated with smartphone platform was further designed for the visualization, on-site and quantitative detection of Cd 2+ . The colorimetric fluorescent sensor was prepared by mixing orange emission glutathione-stabilized gold nanoclusters (AuNCs) with blue emission ethylenediamine functionalized graphene oxide (EDA-GO), and introducing copper ions (Cu 2+ ) to quench the orange emission of AuNCs while the blue emission served as a background reference without color change. The Cd 2+ can induce Cu 2+ -GSH-AuNCs to aggregation and emit orange fluorescence, causing the fluorescent color of the sensor changed from blue to red with the limit of detection (LOD) as low as 33.3 nM in solution. Moreover, fluorescent paper strips integrated with smartphone platform has a sensitive detection of Cd 2+ with the LOD of 0.1 μM in rice samples. The method reported here might have great application prospects in real-time monitoring of foods safety and environmental protection., Competing Interests: Declaration of Competing Interest There are no conflicts to declare., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Microfluidic paper-based analytical devices (μPADs) are a versatile and inexpensive point-of-care (POC) technology, but their widespread adoption has been limited by slow flow rates and the inability to carry out complex in field analytical measurements. In the present work, we investigate multilayer μPADs as a means to generate enhanced flow rates within self-pumping paper devices. Through optical and electrochemical measurements, the fluid dynamics are investigated and compared to established flow theories within μPADs. We demonstrate a ∼145-fold increase in flow rate (velocity = 1.56 cm s -1 , volumetric flow rate = 1.65 mL min -1 , over 5.5 cm) through precise control of the channel height in a 2 layer paper device, as compared to archetypical 1 layer μPAD designs. These design considerations are then applied to a self-pumping sequential injection device format, known as a three-dimensional paper network (3DPN). These 3DPN devices are characterized through flow injection analysis of a ferrocene complex and anodic stripping detection of cadmium, exhibiting a 5× enhancement in signal compared to stationary measurements.

This work reports the fabrication of integrated electrochemical fluidic paper-based analytical devices (ePADs) using a marker pen drawing and screen-printing. Electrodes were deposited on paper using screen-printing with conductive carbon ink. Then, the desired fluidic patterns were formed on the paper substrate by drawing with a commercial hydrophobic marker pen using an inexpensive computer-controlled x-y plotter. The working electrode was characterized by cyclic voltammetry and scanning electron microscopy. The analytical utility of the electrochemical PADs is demonstrated through electrochemical determination of Pb(II) and Cd(II) by anodic stripping voltammetry. For this purpose, the sample was mixed with a buffer solution and a Bi(III) solution, applied to the test zone of the PAD, the metals were preconcentrated as a bismuth alloy on the electrode surface and oxidized by applying an anodic potential scan. The proposed manufacturing approach enables the large-scale fabrication of fit-for-purpose disposable PADs at low cost which can be used for rapid on-site environmental monitoring.

The fabrication of a fully bio-sourced adsorbent of Cd(II) by covalent immobilization of quinine on cellulose paper is described. The double bond of commercially available quinine was converted to a terminal alkyne function which was reacted with cellulose paper, chemically modified with azide functions, through a 1,3-dipolar cycloaddition, leading to Cell-Quin. The adsorption efficiency of Cell-Quin was investigated to determine the optimal pH, contact time and dose of adsorbent, ultimately leading to high levels of removal. The mechanism of adsorption of Cell-Quin was deeply rationalized through kinetic experiments and isotherm modeling. We also showed that Cell-Quin could adsorb other heavy metals such as Cu(II), Pb(II), Ni(II) and Zn (II)., (Copyright © 2019. Published by Elsevier B.V.)

A disposable electrochemical lateral flow paper-based sensing device for heavy metal detection is proposed. The quantification of lead and cadmium in aqueous samples is demonstrated in a range from 10 to 100 ppb with a limit of detection of 7 and 11 ppb respectively. Moreover, the platform itself, which is made of paper, served as a sample pretreatment material due to its filtering properties. Real samples, especially in which the matrix is usually turbid and would in principle need a previous filtration, are successfully analyzed. This lab-on-paper device is simple, low cost, easy to fabricate, and portable, being a promising tool for new point-of-care applications in environmental monitoring, public health, and food safety.

We successfully absorbed the copper ion (Cu 2+ ) and cadmium ion (Cd 2+ ) from alkaline aqueous solutions using the prepared chitosan-tannin (CTS/TA) functional paper as absorbent materials. The kinetics of the adsorption, the adsorption isotherms, and the influence of the solution flow rate and pH were investigated detailly. The adsorption data were described well by Langmuir isotherms, with maximum copper (Cu 2+ ) and cadmium (Cd 2+ ) adsorption capacities of 684.93 and 813.01 mg/m 2 , respectively. The experimental results also showed that the adsorption of these heavy metals was selective in the order of Cu 2+  > Cd 2+ , as Cu 2+ competed with Cd 2+ for bonding sites at solution concentrations greater than or equal to 200 mg/L. The results of this study illustrated that the chitosan-tannin functional paper materials mainly followed a complexation-adsorption model, and the best adsorption capacity was achieved at pH = 9. The desorption of heavy ions from this adsorbent and its reusability of functional paper was also involved. Therefore, this novel, environment-friendly functional paper can surely act as an effective adsorbent for the removal and recovery of heavy metals in alkaline aqueous solutions., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

We studied the avoidance behaviour of the earthworm Eisenia fetida towards Cd, Cu, and Zn, trace elements (TEs) tested as chloride, nitrate and sulphate salts. Sub adults were exposed individually using dual-cell chambers at 20+2°C in the dark. Recordings were realised at different dates from 2h to 32h. We used filter paper and extruded water agar gel as exposure media to evaluate the contribution of the dermal and the digestive exposure routes on the avoidance reactions. Exposures to Cu or Cd (10mgmetal ionL(-1)) resulted in highly significant avoidance reactions through the exposure duration. Worms avoided Zn poorly and reactions towards Zn salts varied along the exposure. Worm sensitivity towards TEs differed between salts and this could result from differential toxicity or accessibility of these TE salts to earthworms. The anion in itself was not the determinant of the avoidance reactions since exposures to similar concentrations of these anions using calcium salts did not result in significant avoidance worm behaviour. Avoidance responses towards TEs were higher in the case of water agar exposures than in filter paper exposures. Thus, dermal contacts with TE solutions would elicit worm avoidance but signals from receptors located inside the digestive tract could reinforce this behaviour. The use of extruded water agar gels as the substrate allows checking the real sensitivity of earthworm species towards TEs since the TE concentrations leading to significant avoidance reactions were below those reported in the literature when using TE-spiked soils., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Combined paper mill biosolids (PB) and forest-derived liming by-products improve soil properties, but their residual effects following several years of application have hardly been investigated. A 13-year (2009–2021) field study was initiated at Yamachiche, QC, Canada, to assess the residual effects of PB and liming materials on the properties of a loamy soil. The PB was applied during nine consecutive years (2000–2008) at 0, 30, 60, and 90 Mg wet·ha−1, whereas the 30 Mg PB·ha−1 rate also received one of three liming materials (calcitic lime, lime mud, wood ash) at 3 Mg wet·ha−1. No amendment was applied during residual years. Past liming materials continued to increase soil pH but their effect decreased over time; meanwhile, past PB applications caused a low increase in residual soil NO3-N. Soil total C, which represented 40% of added organic C when PB applications ceased, stabilized to 15% after six years. Soil Mehlich-3-extractable contents declined over the thirteen residual years to be not significant for P, K, and Cu, while they reached half the values of the application years for Zn and Cd. Conversely, Mehlich-3 Ca was little affected by time. Therefore, land PB and liming material applications benefited soil properties several years after their cessation. [ABSTRACT FROM AUTHOR]

An engineered biochar was fabricated via paper mill sludge pyrolysis under CO 2 atmosphere, and its adsorption capability for As(V) and Cd(II) in aqueous solution was evaluated in a batch mode. The characterization results revealed that the biochar had the structure of complex aggregates containing solid minerals (FeO, Fe 3 O 4 and CaCO 3 ) and graphitic carbon. Adsorption studies were carried out covering various parameters including pH effect, contact time, initial concentrations, competitive ions, and desorption. The adsorption of As(V) and Cd(II) reached apparent equilibrium at 180min, and followed the pseudo-second-order kinetics. The highest equilibrium uptakes of As(V) and Cd(II) were 22.8 and 41.6mgg -1 , respectively. The adsorption isotherms were better described by Redlich-Peterson model. The decrease in As(V) adsorption was apparent with the increase in PO 4 3- concentration, and a similar inhibition effect was observed for Cd(II) adsorption with Ni(II) ion. The feasibility of regeneration was demonstrated through desorption by NaOH or HCl., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The presence of toxic metals on paper pulp and the migration of these metals to food from the food package is receiving significant attention. The final exposure levels for consumers depend on two main processes. First the potential of metals to bind paper pulp during manufacture. Second, the metal potential to migrate from paper to food during storage and use. Binding and unbinding processes are modelled for cadmium kinetics through kinetic approaches. The cadmium concentration in paper pulp is estimated from the cadmium concentration in the water-pulp liquor during manufacture, the temperature, and contact time. Two food simulants have been employed for desorption studies, water and acetic solution (3%, w/w). As expected, under acidic conditions desorption is total and rapid (close to 100% desorption reached in a few minutes). However, the desorption of cadmium into the neutral food simulant depends on the initial cadmium concentration in the paper pulp, temperature and contact time. Surface response curves for each combination are presented. Temperature did not affect cadmium binding, but played a significant role for the desorption processes into the neutral food simulant. The proposed equations offer a good fitting of the experimental values, with p < 0.001 and residuals within a factor of 3 for over 99% of the measured data. These models allow estimations of the expected exposure levels in consumers, on the basis of manufacture and use conditions. Linking the expected exposure with toxicity thresholds, such as the admissible daily intake (ADI), would allow a scientific assessment of the maximum acceptable cadmium levels in water-pulp liquors during manufacture and in the final paper pulp on the basic of the use patterns of each food packaging material.

Several assays have been carried out in order to study in detail the cadmium mobility from water to virgin pulp as previous step of cadmium mobility description from paper into food. Virgin pulp has been immersed in different concentration aqueous solutions at several temperatures and during short and long time. The absorbed cadmium amounts have been measured by atomic absorption spectroscopy. For a long time, the temperature of storage is not an important factor except during the first 3 h. In general, percentage of migrated cadmium into pulp is between 30% and 90% of initial charge. Kinetic equation of cadmium mobility has been described employing statistics methods with a very good correlation.

Contents of pollutant elements lead and cadmium in toilet paper were determined by atomic absorption spectrometry. Both lead and cadmium has good linear relationship that lead is over the range of 0.00-10.00 micrograms.mL-1 (r = 0.9989) and cadmium is over the range of 0.00-4.00 micrograms.mL-1 (r = 0.9997). In this method, RSD is bellow 3.08% and recovery is over the range of 94.8%-104.5%. The method is simple and accurate. It can be used as monitor method of lead and cadmium in toilet paper.

Paper-based ion-selective electrodes (ISEs) are simple, flexible, and cost-efficient in comparison to conventional solid-contact ISEs. Yet, paper-based ISEs have poor limits of detection (in the micromolar range) relative to conventional solid-contact ISEs. Here we describe the construction and optimization of ISEs based on commercially available filter paper modified with single-walled carbon nanotubes (SWCNTs), sputtered gold, and conductive polymer poly(3-octylthiophene) to support an ion-selective membrane. The ion-selective membrane presented here is based on the copolymer methyl methacrylate-decyl methacrylate (MMA-DMA). The copolymer MMA-DMA is highly water-repellent and has a low coefficient of diffusion, which makes it particularly suitable for the creation of sensors with high performance in reaching low limits of detection. Three different configurations of the electrodes have been characterized by using contact angle surface analysis, oxygen influence, and testing for the presence of a water layer. Paper-strip ISEs for cadmium, silver, and potassium ions were developed with groundbreaking limits of detection of 1.2, 25.1, and 11.0 nM, respectively. In addition to such low limits of detection, paper-strip ISEs display high selectivity for their ion of interest and high reproducibility.

Low cost disposable working electrodes are specifically desired for practical applications of electrochemical detection considering maturity of electrochemical stations and data collection protocols. In this paper double-sided conductive adhesive carbon tape with nanostructure was applied to fabricate disposable working electrodes. Being supported by indium tin oxide glass, the prepared carbon tape electrodes were coated with bismuth film for stripping analysis of heavy metal ions. By integrating the bismuth modified electrodes with paper-based analytical devices, we were able to differentiate Zn, Cd and Pb ions with the sample volume of around 15 μL. After the optimization of parameters, including modification of bismuth film and the area of the electrodes, etc., Pb ions could be measured in the linear range from 10 to 500 μg/L with the detection limit of 2 μg/L. Our experimental results revealed that the disposable modified electrodes could be used to quantify migrated lead from toys with the results agreed well with that using atomic absorption spectrometry. Although bismuth modification and stripping analysis could be influenced by the low conductivity of the carbon tape, the low cost disposable carbon tape electrodes take the advantages of large-scaled produced double-sided carbon tape, including its reproducible nanostructure and scaled-up fabrication process. In addition, the preparation of disposable electrodes avoids time-consuming pretreatment and experienced operation. This study implied that the carbon tape might be an alternative candidate for practical applications of electrochemical detection., (© 2013 Elsevier B.V. All rights reserved.)

Nowadays, the development of systems, devices, or methods that integrate several process steps into one multifunctional step for clinical, environmental, or industrial purposes constitutes a challenge for many ongoing research projects. Here, we present a new integrated paper based cadmium (Cd(2+)) immunosensing system in lateral flow format, which integrates the sample treatment process with the analyte detection process. The principle of Cd(2+) detection is based on competitive reaction between the cadmium-ethylenediaminetetraacetic acid-bovine serum albumin-gold nanoparticles (Cd-EDTA-BSA-AuNP) conjugate deposited on the conjugation pad strip and the Cd-EDTA complex formed in the analysis sample for the same binding sites of the 2A81G5 monoclonal antibody (mAb), specific to Cd-EDTA but not Cd(2+) free, which is immobilized onto the test line. This platform operates without any sample pretreatment step for Cd(2+) detection thanks to an extra conjugation pad that ensures Cd(2+) complexation with EDTA and interference masking through ovalbumin (OVA). The detection and quantification limits found for the device were 0.1 and 0.4 ppb, respectively, these being the lowest limits reported up to now for metal sensors based on paper. The accuracy of the device was evaluated by addition of known quantities of Cd(2+) to different drinking water samples and subsequent Cd(2+) content analysis. Sample recoveries ranged from 95 to 105% and the coefficient of variation for the intermediate precision assay was less than 10%. In addition, the results obtained here were compared with those obtained with the well-established inductively coupled plasma emission spectroscopy (ICPES) and the analysis of certificate standard samples.

By using sensing technology, the individual component analysis at trace level in complex samples remains problematic simply because of various interfering species. For example, the determination of Cd(2+) in rice is difficult due to the co-existing interfering metal cations at thousands or even millions of times higher concentrations. In this study, a heavy-metal ion sensitive BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene)-based fluorometric paper sensor with assistance of solid phase extraction (SPE) was developed for the highly selective and sensitive determination of trace Cd(2+) in rice. SPE column packed with prepared sulfonated PS-DVB microspheres was employed to enrich trace Cd(2+) and meanwhile remove most interfering heavy-metal ions in simulated complex rice sample with oxalic acid as eluent, which was theoretically selected on the basis of f values. Mn(2+), as a major coexistent heavy-metal ion, could not be easily removed by SPE, but showed little fluorescent response for BODIPY fluorometric paper sensor even in excess amounts. Combining the separation and enrichment capability of SPE column with the selectivity of BODIPY-based fluorometric paper sensor, we were able to detect trace Cd(2+) in complex samples. The response of fluorometric paper sensor was linearly related with Cd(2+) concentrations in the range of 0.5-4 μM, with a detection limit of 0.5 μM. Twelve real rice samples spiked with Cd(2+) were analysed using this method and the results are in good agreement with ICP-MS measurements.

Paper-ash is used for remediation of heavily contaminated soils with metals, but remediation efficiency after longer periods has not been reported. To gain insights into the mechanisms of immobilization of cadmium (Cd), lead (Pb), and znic (Zn), a study was performed in the laboratory experiment in uncontaminated, artificially contaminated, and remediated soils, and these soils treated with sulfate, to mimic conditions in contaminated soil from zinc smelter site. Remediation was performed by mixing contaminated soil with paper-ash to immobilize Cd, Pb, and Zn in the geotechnical composite. Partitioning of Cd, Pb, and Zn was studied over one year in seven-time intervals applying the sequential extraction procedure and complementary X-ray diffraction analyses. This methodological approach enabled us to follow the redistribution of Cd, Pb, and Zn over time, thus, to studying immobilization mechanisms and assessing the remediation efficiency and stability of newly formed mineral phases. Cd, Pb, and Zn were effectively immobilized by precipitation of insoluble hydroxides after the addition of paper-ash and by the carbonization process in insoluble carbonate minerals. After remediation, Cd, Pb, and Zn concentrations in the water-soluble fraction were well below the limiting values for inertness: Cd by 100 times, Pb by 125 times, and Zn by 10 times. Sulfate treatment did not influence the remediation efficiency. Experimental data confirmed the high remediation efficiency and stability of insoluble Cd, Pb, and Zn mineral phases in geotechnical composites.

Cadmium (Cd) is a very poisonous and non-essential heavy metal which is easily absorbed by plants. The metal makes living organisms susceptible to its acute and chronic toxicity through plant food. Similarly, Cd hinders the growth of plants by causing the loss of chlorophyll, which in turn negatively impacts the activities of photosynthesis. Therefore, this current study aims to evaluate the effects of Cd on the germination behaviour, morphology, growth and development of Pak Choi plants. The sterilized Pak Choi seeds were germinated on a soaked filter paper of a petri dish. The petri dish included seven different treatments of Cd chloride with concentrations of 0, 0.01, 0.05, 0.1, 0.2, 0.3, and 0.4 mM. Each treatment was replicated five times. The germination and growth of the seeds were observed for 15 days. Pak Choi seedlings were also planted under hydroponic conditions to investigate their morphological characteristics, growth and development. After two weeks of growth, the application of CdCl2 was made with four treatments consisting of nutrient solution without CdCl2 (control) and 0.1, 0.5 and 1.0 mM CdCl2 -nutrient solution. Two weeks of plant growth were allowed before the experiment was terminated. At the end of the experiment, the chlorophyll content (SPAD), root and shoot length (cm), and fresh and dry weight (g) of plants were quantified accordingly. The increase in CdCl2 concentration led to a significant decrease in the length of root and shoot of germinated seedlings significantly. The seedling's growth of Pak Choi was inhibited three days after germination, and the seedling's height (root and shoot) in higher concentrations of CdCl2 was lower than lower doses of Cd. Chlorosis symptoms in the leaf were visible in hydroponic Pak Choi containing Cd. The growth of Cd-treated hydroponic Pak Choi was adversely affected by Cd treatment. The Cd treatment also reduced SPAD, biomass content (fresh and dry), and length of root and leaves number significantly. It can be concluded that exogenous Cd inhibits the Pak Choi germination and growth under hydroponic conditions. [ABSTRACT FROM AUTHOR]

It is crucial to investigate the effects of mixtures of contaminants on aquatic organisms, because they reflect what occurs in the environment. Cadmium (Cd) and nickel (Ni) are metals that co-occur in aquatic ecosystems, and information is scarce on their joint toxicity to Chlorophyceae using multiple endpoints. We evaluated the effects of isolated and combined Cd and Ni metals on multiple endpoints of the chlorophycean Raphidocelis subcapitata. The results showed that Cd inhibited cell density, increased reactive oxygen species (ROS) production (up to 308% at 0.075 mg L -1 of Cd), chlorophyll a (Chl a) fluorescence (0.050-0.100 mg L -1 of Cd), cell size (0.025-0.100 mg L -1 of Cd), and cell complexity in all concentrations evaluated. Nickel exposure decreased ROS production by up to 25% at 0.25 mg L -1 of Ni and Chl a fluorescence in all concentrations assessed. Cell density and oxygen-evolving complex (initial fluorescence/variable fluorescence [F 0 /F v ]) were only affected at 0.5 mg L -1 of Ni. In terms of algal growth, mixture toxicity showed antagonism at low doses and synergism at high doses, with a dose level change greater than the median inhibitory concentration. The independent action model and dose-level-dependent deviation best fit our data. Cadmium and Ni mixtures resulted in a significant increase in cell size and cell complexity, as well as changes in ROS production and Chl a fluorescence, and they did not affect the photosynthetic parameters. Environ Toxicol Chem 2024;43:1855-1869. © 2024 SETAC., (© 2024 SETAC.)

Synthetic 11 Å tobermorite (Ca5Si6O16(OH)2.4H2O) and its Al-substituted analogue are layer-lattice ion-exchangers with potential applications in nuclear and hazardous wastewater treatment. The present study reports the facile one-pot hydrothermal synthesis of an Al-tobermorite-rich cation-exchanger from a combination of paper recycling ash, post-consumer container glass, and lime, with compositional ratios of [Ca]/[Si + Al] = 0.81 and [Al]/[Si + Al] = 0.18. The reaction products were characterized by powder X-ray diffraction analysis, 29Si magic angle spinning nuclear magnetic resonance spectroscopy, and scanning electron microscopy. Hydrothermal processing in 4 M NaOH(aq) at 100 °C for 7 days yielded an Al-tobermorite-rich product that also contained katoite (Ca3Al2SiO12H8), portlandite (Ca(OH)2), calcite (CaCO3), and amorphous silicate gel. The hydrothermal product was found to have a Cs+ cation exchange capacity of 59 ± 4 meq 100 g−1 and selective Cs+ distribution coefficients (Kd) of 574 ± 13 and 658 ± 34 cm3 g−1 from solutions with molar ratios [Cs+]:[Na+] and [Cs+]:[Ca2+] of 1:100. In a batch sorption study at 20 °C, the uptakes of Pb2+, Cd2+, and Cs+ were determined to be 1.78 ± 0.04, 0.65 ± 0.06, and 0.36 ± 0.03 mmol g−1, respectively. The kinetics of Pb2+, Cd2+, and Cs+ removal were described by the pseudo-second-order rate model, which gave respective rate constants (k2) of 0.010, 0.027, and 1.635 g mmol−1 min−1, and corresponding correlation coefficients (R2) of 0.997, 0.996, and 0.999. The metal ion sorption properties of the tobermorite-rich product compared favorably with those of other waste-derived tobermorites reported in the literature. Potential strategies to improve the yield, crystallinity, and sorption characteristics of the product are discussed. [ABSTRACT FROM AUTHOR]

The wastewater effluent is responsible for the major ecological impact of the dairy sectors. To avoid the negative consequences of heavy metal pollution on the ecosystem, creative, affordable, and efficient treatment methods are now required before the effluent flows into the surrounding area. This study was aimed at assessing the effectiveness of three different adsorbents for Cd +2 and Cr +6 ions from wastewater effluents of dairy farms, including chitosan (CS), clinoptilolite zeolite (CZ), and chitosan/clinoptilolite zeolite (CS/CZ) composite. The adsorption kinetics of the CS/CZ composite were established using the effects of the key variables (pH, agitation speed, adsorbent concentrations, and contact durations). The removal (%) and adsorption capacities, q e (mg/g), were calculated using the data from the adsorption kinetics. Wastewater samples (n = 60) were collected from the wastewater effluents of five farms. Cd +2 and Cr +6 ion concentrations in all collected samples were determined. Following the CS/CZ composite creation, it was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (X-RD), and Fourier-transform infrared spectrum (FT-IR). The CS/CZ composite had an adsorption capacity of 92.4 and 96.5 mg/g for both Cd +2 and Cr +6 ions at a concentration of 2.0 g/100 ml, respectively, while the CZ adsorption capacities for the two ions were 87.5 mg/g and 61.0 mg/g, respectively, at 4.0 g/100 ml concentration. The CS was achieved at 55.56 mg/g and 33.3 mg/g, respectively, at the same concentration. The efficiency of heavy metal removal was enhanced by increasing adsorbent concentration, agitation speed, and contact duration. Using CS/CZ composite at 2.0 g/100 ml concentration, 180 min of contact time, and 300 rpm agitation speed, the greatest removal efficiencies for Cd +2 and Cr +6 ions (96.43 and 98.75%, respectively) were demonstrated., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

In this study, the safety of a red mud-loess mixture (RM-L) for the remediation of groundwater polluted by acid mine drainage (AMD) containing Cd(II) in mining areas was systematically analyzed and clarified. The effects of the initial concentration, flow rate, and packing height on the breakthrough performance and longevity of RM-L as a permeable reactive barrier (PRB) packing material were explored by column tests. The results show that the breakthrough time, saturation time, and adsorption capacity of Cd(II) in RM-L increased with decreasing initial concentration and flow rate, as well as increasing packing height. Moreover, RM-L had a long-term effective acid buffering capacity for acidic wastewater containing Cd(II). An increase in the packing height led to a longer longevity of the PRB than the theoretical value. In addition, the speciation of Cd on RM-L was dominated by carbonate form and iron-manganese oxide form. The surface of the RM-L particles evolved from a dense lamellar structure to small globular clusters after purifying the acidic wastewater containing Cd(II), due to the corrosion of H + and the reoccupation and coverage by increasingly enriched adsorbates and precipitates of heavy metal ions., Competing Interests: The authors declare there is no conflict., (© 2024 The Authors This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).)

• A stack-up micro electrochemical device was developed based on the carbon paper electrode. • Cobalt-based MOFs and gold nanoparticles improved the metal ion absorption and electron diffusion. • Sensitive simultaneous determination of Pb2+ and Cd2+ achieved the subnanogram LODs. A portable device is conducive to the on-site detection of heavy metal ions at trace level in food and the prevention of related food safety issues. In this work, an electrochemical device stacked up with flat electrodes was developed for the detection of Pb2+ and Cd2+. The top layer of the device is a carbon paper as working electrode, which is modified with amino functionalized cobalt-based metal-organic framework and gold nanoparticles. The bottom layer was constructed with the carbon counter electrode and Ag/AgCl reference electrode, and a punched sample cell (Φ = 8 mm) was in the middle. The proposed method could simultaneously determinate Pb2+ and Cd2+ via anodic stripping voltammetry with the detection limit of 7.0 × 10−2 ng mL−1 and 1.1 × 10−2 ng mL−1, and was applied in real food samples (drinking water, juice, tea, grain, fruits, vegetables, liver and aquatic products) with the recovery of 91.2–105.4 % and 90.2–111.2 %, respectively. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) has high rates of soil-to-plant transference, coupled with its non-biodegradability and persistence; long-term management of Cd in agriculture is thus required to ensure better soil and food security and safety. Identifications of regions with high soil Cd concentration or high dietary Cd intakes are critical public health priorities. Human health risk assessment for dietary Cd intake was thus undertaken by employing three approaches: FCA (food chain approach), TDA (total diet approach), and FQA (food quality approach). The correlation between green/total vegetable consumption rates and dietary Cd intake from vegetables was statistically significant. For consumption, the hazard quotients (HQs) calculated by FCA and TDA were all less than 1 except for Hunan and Sichuan province. For rice consumption, the HQs derived by FCA or TDA approach for eight provinces exceeded 1. Residents in Hubei, Guangxi, Jilin, Zhejiang, Liaoning, Shanghai, Sichuan, and Guangxi were more vulnerable due to their notable higher consumption rates.Weighted rankings of the health risk levels were determined to derive the comparative risk management priority. For Cd intake from vegetables, four provinces/cities have high relative priority; for Cd intake from grains, three provinces have high relative priority. The comparative risk management priority for Hunan and Sichuan was high for dietary intake from vegetables or rice. Weighted average HQs were derived to determine the integrated dietary Cd intake health risk levels for dietary intake from vegetables or grains. The risk levels for Hunan, Guangxi, Sichuan, and Zhejiang are high, so effective measures should be taken to reduce Cd dietary intakes to ensure health protection.It is envisaged that the methodology employed in this study could provide useful insights into how various approaches can be integrated to determine human health risk levels for Cd intake, so more effective and targeted measures can be taken accordingly for the relevant regions., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Although irrigation water is a fundamental need for plant growth, it is also a source of pollutants if contaminated with harmful materials like cadmium (Cd). Irrigation water possessing abundant Cd causes damage to soil, plants, animals and ultimately human beings through the food chain. A pot experiment was conducted to evaluate the gladiolus (Gladiolus grandiflora L.) potential of Cd accumulation and the capability of the plant to be an economically beneficial choice in presence of high Cd irrigation water supply. Artificially prepared four levels of Cd irrigation water were applied to the plants viz., 30, 60, 90 and 120 mg L -1 . The results revealed that 30 mg L -1 Cd had no difference in all growth-related parameters when compared to the control. Photosynthesis rate, stomatal conductance and transpiration rate along with plant height and spike length were reduced with high accumulation levels of Cd in plants. The main plant portion for Cd storage found in Gladiolus grandiflora L was corm where the amount of Cd was 10-12 times higher than the amount found in leaves, and 2-4 times more than the stem. This deportment was further established by the translocation factor (TF). In corm to shoot TF and corm to stem TF, the factor reduced with increasing Cd levels, while, in corm to leaves TF, Cd levels were statistically non-significant. From corm to shoot TF value of 0.68 and 0.43 in case of 30 and 60 mg L -1 , Cd treatments indicates good phytoremediation potential of Gladiolus in low and moderate Cd-polluted environments. Conclusively, the study reveals the good capability of Gladiolus grandiflora L. to harvest Cd from the soil and water in reasonably good amount with sufficient potential to grow under irrigation-based Cd stress. Under revelations of the study, Gladiolus grandiflora L appeared as a Cd accumulator which could potentially be used as a sustainable approach for phytoremediation of Cd., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

A novel and highly sensitive immunochromatographic strip based on a monoclonal antibody (3A9) was developed for the detection of cadmium in tap water. The 50% inhibition concentration of the antibody, which showed no cross-reactivity with other heavy metal ions, was 0.45 ng/mL and it recognized Cd(II)–1-(4-isothiocyanobenzyl) ethylenediamine-N,N,N′,N′-tetraacetic acid (EDTA) (Cd(II)–ITCBE) and not metal-free ITCBE and EDTA. The cutoff value for semi-quantitative detection of the strip was 5 ng/mL and the lower limit of detection for quantitative detection was 0.2 ng/mL using a scanning reader. The percent recovery ranged from 107.6% to 132% in tap water samples.

The possibility of using pyrolyzed paper as disposable working electrodes for trace metals determination is reported for the first time. A small piece of pyrolyzed paper (0.7×0.7 cm) was positioned at the bottom side of the electrochemical cell using a rubber O-ring, which defined the electrode area (0.48 cm; 0.18 cm 2 ). A large number of electrodes can be obtained from a single piece of standard dimensions (2.5 cm×7.5 cm) of paper, therefore minimizing the cost per unit. The electrochemical performance of the pyrolyzed paper was demonstrated by cyclic voltammetry, electrochemical impedance spectroscopy and by the determination of Zn, Cd, and Pb by square-wave anodic stripping voltammetry. The unmodified pyrolyzed paper showed excellent performance for Pb and Cd detection (LOD =0.19 and 0.16 ppb, respectively). In the presence of Bi 3+ (in-situ film formation), the simultaneous determination of Zn, Cd and Pb was also possible (LOD=0.26, 0.25, and 0.39 ppb, respectively). [ABSTRACT FROM AUTHOR]