Detection Of Heavy Metals Research Articles

PÓSTER] New fluorescent Schiff base modified nanocellulose-based chemosensors for the selective detection of Fe3+, Zn2+ and Cu2+ in semi-aqueous media and application in seawater sample

Cellulose is the most abundant linear carbohydrate bio-polymer in nature. It’s well-known as the most renewable, biocompatible, biodegradable, cost-effective and eco-friendly. In recent years, the shift from MCC to nanocellulose NC has rapidly attracted a great attention and has gained much interest as a new class of nanoscale biopolymers and as the new renewable source from both academia and industry researchers due to its promising potential in applications. NC is specifically characterized by a great dispersibility, high aspect ratio, large surface area, high mechanical strength, high crystallinity and thermal expansion coefficient. Thus, Schiff bases with an azomethine or imine (-C=N-) group have been extensively designed and used in field of cation species sensing, anions, proteins and organic substances, because of their simple preparation, high yield and easy structural modifications that can coordinate different analytes via the pair of electrons of azomethine nitrogen (-C=N) that make various complexes. Fluorometric chemosensors/probes are very effective for the detection and quantification of heavy metal ions, being the recognition simple process, that leads to high sensitivity, distinguished selectivity and excellent efficiency at low-cost. However, these small molecules are sometimes unstable in the surrounding changes in solutions. So, a new alternative has recently proposed using Schiff base-modified cellulose. For example, WANG et al. (2023) [1] developed a fluorescent coumarin derivative grafted dialdehyde cellulose-based probe for the detection of Fe3+. In this study, four new fluorescent dyes, namely, S1: (PDA-DANC), S2: (SAL-PDA-DANC), S3: (BrSAL-PDA-DANC) and S4: (ClSAL-PDA-DANC) have been successfully synthesized from (DANC) for the detection of heavy metal. The microstructural and photophysical properties of (NC), (DANC) and the synthesized dyes were investigated by FT-IR, SEM-EDX, XRD, TGA, DLS and photoluminescence.

Advances in Graphene-Based Materials for Metal Ion Sensing and Wastewater Treatment: A Review

Graphene-based materials, including graphene oxide (GO) and functionalized derivatives, have demonstrated exceptional potential in addressing environmental challenges related to heavy metal detection and wastewater treatment. This review presents the latest advancements in graphene-based electrochemical and fluorescence sensors, emphasizing their superior sensitivity and selectivity in detecting metal ions, such as Pb2⁺, Cd2⁺, and Hg2⁺, even in complex matrices. The key focus of this review is on the use of molecular dynamics (MD) simulations to understand and predict ion transport through graphene membranes, offering insights into their mechanisms and efficiency in removing contaminants. Particularly, this article reviews the effects of external conditions, pore radius, functionalization, and multilayers on water purification to provide comprehensive insights into filtration membrane design. Functionalized graphene membranes exhibit enhanced ion rejection through tailored electrostatic interactions and size exclusion effects, achieving up to 100% rejection rates for selected heavy metals. Multilayered and hybrid graphene composites further improve filtration performance and structural stability, enabling sustainable, large-scale water purification. However, challenges related to fabrication scalability, environmental impact, and cost remain. This review also highlights the importance of computational approaches and innovative material designs in overcoming these barriers, paving the way for future breakthroughs in graphene-based filtration technologies.

Pharmacognostical, Physicochemical Evaluation, and In Vitro Anti-obesity Investigation of Citrullus colocynthis Linn. Fruits from Western Haryana

Background: Cucurbitaceae family plants have been widely used as traditional medicines for the prevention and treatment of many ailments. Citrullus colocynthis Linnaeus also known as Colocynth, is a bitter plant commonly found growing in sandy deserts around the world, and it grows naturally in the Western Haryana region. Fruits of this plant have been utilized traditionally for various medicinal purposes, like as an appetite suppressant, hypoglycemic, diuretic, laxative, anthelmintic, and for treating renal stones. Objective: The objective of this study is to carry out the in vitro anti-obesity investigation, pharmacognostical studies, heavy metal and pesticide residue analysis, microbial contamination, and mycotoxins evaluation of the Citrullus colocynthis fruits for establishing their quality, safety, efficacy, and purity standards. Methods: Fresh fruits were collected and taxonomically authenticated. The pharmacognostical characteristics of the intact and powdered fruits were identified and qualitative and quantitative phytochemical evaluation was performed. Physicochemical evaluation, heavy metal and pesticide residue detection, microbial contamination, and mycotoxins analysis were performed as per WHO guidelines 2011. In vitro inhibition activities for pancreatic lipase and α-amylase enzymes were carried out as per standard procedures and IC50 values were recorded. Results: The pharmacognostical standards viz. macroscopy, microscopy and physicochemical parameters were laid, and the drug was declared free from microbial contamination and mycotoxins. Heavy metal analysis and pesticide residue detection revealed that their presence was below toxic levels. The Powder microscopy, microbial contamination, mycotoxin evaluation, and pesticide residue of the Colocynth fruits are novel findings. The IC50 values (µg/ml) for pancreatic lipase inhibition for aqueous and ethanolic extracts were found to be 21.27±1.25 and 34.35±1.86, and for α-glucosidase, the values were 271.12±2.64 and 283.21±3.06, and for α-glucosidase, the values were 295.67±2.92 and 306.15±3.44 respectively. Thus, the fruit extracts showed significant in vitro anti-obesity potential. Conclusion: Pharmacognostical and physicochemical studies prove to be useful in reducing commercial adulteration of the crude drug by assuring their purity and identity and this could further help in improving the quality of formulations incorporating it. The results of various standardization parameters could be used for designing the monograph of the crude drug. The fruits were found to be fit for therapeutic consumption and their extracts have shown good pancreatic lipase inhibition. The in vitro anti-obesity investigation findings of the fruit extracts can further be explored in-vivo for evaluating their therapeutic efficacy.

Application of nail analysis in human biomonitoring of toxic pollutants: a review.

Nail tissue, as a keratinized biomatrix, serves as a valuable indicator of chronic human exposure to toxic pollutants. The analysis of nail samples has emerged as a prominent method for human exposure assessment, primarily due to its non-invasive sampling procedure and ease of sample storage and transportation. This review examines recent applications of nail analysis in human biomonitoring of toxic organic compounds and heavy metals, along with the various pretreatment methods that have been developed. Studies of human nail samples have revealed distinctive patterns in toxic pollutant accumulation. Brominated flame retardants exhibit significant occupational exposure differences, with concentrations reaching 2.20×106 ng/g in manufacturing workers compared to 67 ng/g in the general population. Organophosphate esters demonstrate notable regional variations, as evidenced by Triphenyl phosphate concentrations of 19.6 ng/g in China versus 770 ng/g in the United States. Additionally, the detection of organic pollutant metabolites in nails provides direct evidence of internal exposure. The 5-14 months detection window characteristic of nail samples enables retrospective exposure analysis, highlighting the promising potential of nail analysis in human biomonitoring. Recent developments include the implementation of in situ analytical methods for rapid heavy metal detection in nail samples. However, a significant challenge remains in differentiating between internal and external sources of most compounds in nails, although the identification of metabolic biomarkers for certain pollutants can minimize external interference and better reflect actual body burden. Further research is required to elucidate the relationships between nail pollutant levels, environmental exposure, and health effects. While existing studies demonstrate the considerable potential of nail analysis in human biomonitoring of toxic pollutants, additional research is necessary to validate and fully realize its practical applications.

Innovative transgenic zebrafish biosensor for heavy metal detection.

Heavy metal contamination is an urgent environmental issue that poses a significant threat to human health and the ecosystem. To mitigate the adverse impacts of heavy metal pollution, the aim of this research was to develop genetically engineered zebrafish as biosensors, which offer a promising alternative for detecting heavy metal exposure, specifically Cd2⁺ and Zn2⁺. A novel heavy metal-sensitive gene construct metallothionine 2 promoter with DsRed reporter gene (mt2-DsRed2) was synthesized and integrated into zebrafish embryos using a Tol2 transposon transposase system with the transgenic zebrafish line subjected to biosensing applications for Cd2+ and Zn2+. The biosensor showed specific responses with linear correlation heavy metal concentration and DsRed fluorescence signal for Cd2+ and Zn2+ with (p<0.01) a minimum detection limit of 4ppb for each metal ion but not for the non-specific metal ion Ni2+, which makes it suitable for laboratory-based heavy metal assessment assays in the low heavy metal concentration ranges of 0-10ppb. Additionally, the study investigated the toxicity of heavy metals on zebrafish early developmental stages applying a modified version of the OECD Fish Embryo Toxicity (FET-236) test. Accordingly, Cd2+, Zn2+, and Ni2+ exhibited no significant toxicity effects on zebrafish embryos within the low dose range of 2-10ppb confirming the biocompatibility of the transgenic zebrafish biosensor for heavy metal sensing applications. Thus, the developed transgenic zebrafish line can accurately sense heavy metals Cd2+ and Zn2+ within the low dose range, making it a promising alternative laboratory assay for environmental monitoring and risk assessment.

Correction to: Heavy metal detection in industrial waste water using Ficus Benjamina leaf extract–mediated Ag nanoparticles

Correction to: Heavy metal detection in industrial waste water using Ficus Benjamina leaf extract–mediated Ag nanoparticles

Assessment of environmental impacts of heavy metal pollution in rice in Nanning, China

Nowadays rice has become one of the world’s staple foods. Rice in southern China is also a staple food for everyone, however, with the development of China’s industrialization model, many industrial areas may be contaminated by heavy metals, leading to contamination of the agricultural areas. With the development of recent years, Nanning has become a heavily industrial development area, and rice is also a favourite staple food. Therefore, it is a matter of concern to detect whether heavy metals contaminate rice in Nanning due to environmental factors. Five administrative villages were selected from 12 districts, and 20% of the natural villages were randomly selected for soil and water sample taking using probability distribution points and making the number of samples in each village evenly distributed. The single gene index pollution method and Nemerow composite pollution index method was used to evaluate whether heavy metals polluted the crops. Rice was evaluated through the national standard of Food Safety and Food Contaminant Limits. The survey shows that the heavy metal pollution of rice is moderate, especially cadmium pollution is more serious, but the risk of environmental factors in the Nanning area has a small impact on the overall safety and quality of rice, which is still within the controllable range. The total exceedance rate of heavy metals in the surveyed local rice was 20.95%, and the exceedance rate of paddy rice was 33.33%. The exceedance rates of lead, cadmium, inorganic arsenic, and total mercury in rice were 2.23%, 17.88%, 0.56%, and 0.84% respectively. Cadmium was identified as the primary heavy metal contaminant in local rice, with the highest detected concentration reaching 1.23 mg/kg, which is 6.15 times above the limit set by national health standards. This study shows that the concentration of heavy metals in the environment of Nanning Province is low, and the risk caused by environmental factors has relatively little impact on the safety and quality of rice. However, since the pollution of heavy metals will continue to enrich the food chain with time, long-term use will also cause harm to the human body. Therefore, it is necessary to raise the attention of local governments in rice-producing areas to food safety, and then take effective measures to improve local heavy metal detection technology, improve crop quality, and protect people’s food safety.

Recent advances in designable nanomaterial-based electrochemical sensors for environmental heavy-metal detection.

The detection of heavy metals serves as a defence measure to safeguard the well-being of the human body and the ecological environment. Electrochemical sensors (ECS) offer significant benefits such as exceptional sensitivity, excellent selectivity, affordability, and portability. This review begins by elucidating the ECS principles and delves into recent advancements in the field of heavy metal detection, including the use of metal nanoparticles, carbon-based nanomaterials, and organic framework materials. Advanced materials enhance the sensitivity and selectivity of ECS, allowing it to efficiently and rapidly identify metallic contaminants in food and the environment. Finally, the future development of ECS and challenges encountered in the development process are discussed, and testing materials for the detection of heavy-metal ions for human health and environmental safety are comprehensively considered. This study is likely to attract the interest of environmentalists and those who prioritise human health.

Highly Green Fluorescent Carbon Dots from Gallic Acid: A Turn-On Sensor toward Pb2+ Ions.

Carbon dots (CDs) are emerging novel fluorescent sensing nanomaterials owing to their tunable optical properties, biocompatibility, and eco-friendliness. Herein, we report a facile one-pot hydrothermal route for the synthesis of highly green fluorescent CDs using gallic acid (GA) as a single carbon source in N,N-dimethylformamide (DMF) solvent, which serves as a nitrogen source and reaction medium. The optical properties of the synthesized GA-DMF CDs were systematically characterized by using UV-vis and photoluminescence spectroscopy, revealing strong green fluorescence. Further, to gain insights into their size and structural, elemental, and chemical composition, Fourier transform infrared, dynamic light scattering, high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction, and X-ray photoelectron spectroscopy characterization techniques were performed. HR-TEM analysis confirmed the formation of uniformly spherical GA-DMF CDs with an average particle size of 16 ± 6.1 nm. Notably, the GA-DMF CDs exhibited a highly selective and turn-on fluorescent response to Pb2+ ions in aqueous solutions, which was attributed to a chelation-enhanced fluorescence mechanism. The detection limit for Pb2+ ions was determined to be as low as 7.15 × 10-7 M, with a broad linear detection range of 30-130 μM, underscoring their sensitivity and practical application in water quality monitoring. This study introduces a novel, sustainable approach for synthesizing nitrogen-doped CDs with outstanding optical properties and highlights their unprecedented selectivity toward Pb2+ ions, advancing the development of efficient and eco-friendly sensing platforms for heavy metal detection.

Recent Developments in Heavy Metals Detection: Modified Electrodes, Pretreatment Methods, Prediction Models and Algorithms

Recent Developments in Heavy Metals Detection: Modified Electrodes, Pretreatment Methods, Prediction Models and Algorithms

Facile synthesis of heterojunction CdS-TiO2 nanocomposites for energy storage supercapacitors, heavy metal detection, photochemical applications, and forensic science advancements: a comparative study with pure CdS and TiO2 nanoparticles

Facile synthesis of heterojunction CdS-TiO2 nanocomposites for energy storage supercapacitors, heavy metal detection, photochemical applications, and forensic science advancements: a comparative study with pure CdS and TiO2 nanoparticles

Recent Advances in the Synthesis, Characterization, and Application of Carbon Dots in the Field of Wastewater Treatment: A Comprehensive Review

Carbon dots (CDs), as a revolutionary nanomaterial, exhibit unique advantages in terms of wastewater treatment, offering new opportunities for the development of water treatment technologies due to their simple synthesis methods, excellent biocompatibility, tunable optical properties, and favorable environmental performance. This review systematically discusses the synthesis methods, structural characteristics, and application progress of carbon dots in wastewater treatment, highlighting several key findings. (1) Excellent adsorption performance: CDs can effectively remove heavy metal ions, dyes, and organic pollutants from water. (2) Outstanding photocatalytic performance: Some carbon-dot-enhanced photocatalytic systems can efficiently remove pollutants under visible light. (3) Exceptional selective detection ability: CDs are capable of highly sensitive detection of heavy metals and organic pollutants in water, with the detection limits reaching the nanomolar level. (4) Enhanced membrane separation performance: The high water flux and excellent selectivity of carbon-dot-modified membranes make them suitable for efficient water treatment and water quality separation. (5) Enhancement of biological treatment: In biological treatment systems, CDs can significantly improve the microbial activity and electron transfer efficiency to enhance the efficiency of biological degradation processes. (6) Sustainable utilization of waste as a raw material and regeneration of CDs are conducive to reducing the cost of preparation of CDs. These findings indicate that CDs have broad application potential in wastewater treatment. Furthermore, this review looks ahead to the future development directions of CDs in wastewater treatment, proposing potential innovations in catalytic performance enhancement, cost control, and practical applications, aiming to provide important references and guidance for future research and industrial application of CDs in wastewater treatment.

A signal amplifying MOF-based probe:on-site and ultrasensitive dual-channel portable detection of Hg2+ in groundwater through a fluorimetrically and RGB-based sensing assay.

Mercury (II) ions (Hg2+) are a significant source of heavy metal contamination in groundwater, posing a serious threat to human health and the environment. Therefore, there is an urgent need for the development of a new detection technique with high sensitivity for monitoring Hg2+ in contaminated groundwater. Here, we developed a signal amplifying MOF-based probe (NXS@ZIF-8) for on-site and ultrasensitive dual-channel portable detection of Hg2+ in groundwater. The successful grafting of the fluorescent probe (NXS) onto ZIF-8 effectively enhanced the enrichment of the NXS probe, thereby amplifying the detection signal for Hg2+. Upon exposure to Hg2+, NXS@ZIF-8 quickly emits fluorescent signals, which can be easily detected using portable laser-induced fluorescence spectrometers (LIFs) with a low detection limit of 0.30ppb. Importantly, the platform enables on-site detection of Hg2+ in groundwater samples and direct on-site and in-situ detection of Hg2+ in contaminated groundwater, achieving acceptable results. Furthermore, NXS@ZIF-8 was fabricated as a paper-based sensor and integrated into a portable smartphone device for visual detection of Hg2+ in contaminated groundwater. This work presents an approach for on-site, in-situ and highly sensitive portable detection of heavy metals in contaminated groundwater, eliminating the need for access to specialized laboratory equipment.

Detection of Heavy Metals in Some Fish and Shellfish Marketed in Egypt: Bioaccumulation, Dietary Intake and Health Risk Assessment

Detection of Heavy Metals in Some Fish and Shellfish Marketed in Egypt: Bioaccumulation, Dietary Intake and Health Risk Assessment

A novel spectroscopy-deep learning approach for aqueous multi-heavy metal detection.

Addressing heavy metal contamination in water bodies is a critical concern for environmental scientists. Traditional detection methods are often complex and costly. Recent advancements in artificial intelligence (AI), particularly machine learning (ML) and deep learning (DL), have shown significant potential in analytical chemistry. However, these AI models require extensive spectral data, which traditional methods struggle to provide quickly. To overcome this challenge, we developed a new digital spectral imaging system and rapidly collected 3000 digital spectra from mixed heavy metal samples. We then created an end-to-end regression model for predicting heavy metal concentrations in mixed water samples using deep convolutional neural networks (ResNet-50, Inception V1, and SqueezeNet V1.1). The results indicated that the trained ResNet-50 model can effectively detect arsenic, chromium, and copper simultaneously, with a linear fitting coefficient exceeding 0.99 between true and predicted values. This study offers an efficient approach for rapid heavy metal detection in complex water environments and serves as a reference for developing intelligent analytical techniques.

Effects of heavy metal accumulation mediated by floral rewards on key stages of growth and development of bumblebees (Bombus terrestris L.).

Whether soil heavy metal pollution contributes to the decline in pollinator populations remains inconclusive. Based on the detection of heavy metals in the nectar, pollen, and bodies of pollinating insects in areas affected by heavy metal pollution, this study aimed to investigate the impact of adding four heavy metals-zinc (Zn), lead (Pb), copper (Cu), and nickel (Ni)-at realistic concentrations to the diet on the pre-oviposition period, larval development period, production of adult bees, and weight of worker bees. The study sought to evaluate the influence of heavy metal accumulation mediated by floral rewards on key stages of growth and development of bumblebee (Bombus terrestris L.). Results revealed that Zn, Pb, and Cu significantly extended the pre-oviposition period of queen bees, with Pb doubling the time at high concentrations and Ni showing no significant effect at moderate to low concentrations. Lead, Cu, and Ni significantly extended the larval development period at medium and high concentrations, whereas Zn only had a significant effect at high concentrations. The four heavy metals significantly reduced the adult bee yield and the body weight of worker bees at different concentrations, among which the high concentrations of Pb and Cu significantly reduced the adult bee yield by 25%-40%. The effect of a high concentration of copper on the body weight of worker bees was the most obvious, a reduction by 30%. Our findings support the hypothesis that heavy metal pollution, mediated by floral rewards, can have serious impact on some key stages of growth and development of bumblebees.

Detection of heavy metals in soil using Au@SiO2 nanoparticles and surface microstructure combined with laser-induced breakdown spectroscopy.

The detection of heavy metals in soil is of great scientific significance for food security and human health. However, traditional detection methods are complicated, time-consuming, and labor-intensive. Herein, we developed a novel method using Au@SiO2 nanoparticles (NPs) and surface microstructure combined with laser-induced breakdown spectroscopy (Au@SiO2 NPs-SMS-LIBS) for the rapid detection of lead (Pb), chromium (Cr), and copper (Cu) in soil samples. The surface microstructures and Au@SiO2 NPs were prepared to improve detection sensitivity and stability. The limits of detection (LODs) for Pb, Cr, and Cu were 0.36 mg/kg, 0.32 mg/kg, and 0.28 mg/kg, respectively, with relative standard deviations (RSDs) of 5.47-6.72 %. The mechanisms of spectral performance enhancement of LIBS detection were thoroughly investigated. Furthermore, the stacking combination model was developed to improve quantitative accuracy, with the correlation of the prediction set (Rp2) for Pb, Cr, and Cu being 0.9285, 0.8625, and 0.9160, respectively. This work offers a very promising solution to improve the sensitivity, stability, and accuracy of heavy metal detection. The developed method holds great application potential for large-scale soil assessments and real-time heavy metal pollution monitoring.

Anisomeles malabarica Leaves: Revisiting Pharmacognostic Features and Taxonomic Paradigms

This study investigates the pharmacognostic and phytochemical properties of Anisomeles malabarica, a medicinal plant from the Lamiaceae family. A comprehensive analysis was performed, encompassing macroscopic, microscopic, and numerical taxonomic studies. The anatomical observations revealed distinctive traits such as unicellular trichomes, collenchymatous and parenchymatous ground tissue, and vascular bundles with concentric arrangements. Quantitative microscopy parameters, including stomatal index and vein islet number, were documented. Physiochemical analyses showed values within Ayurvedic pharmacopeia standards, ensuring the plant's purity and quality. The presence of essential inorganic elements like calcium, potassium, and iron was confirmed, with no detection of toxic heavy metals, underscoring its safety for medicinal use. DNA barcoding validated the species identity, enhancing its taxonomic classification. These findings highlight A. malabarica's potential for therapeutic applications and its importance in pharmacognostic standardization.

Employing Mesoporous Nitrogen Containing Carbon for Simultaneous Electrochemical Detection of Heavy Metal Ions.

Heavy metal ions are major contributors to water pollution, posing significant threats to both ecological balance and human health due to their carcinogenic properties. The increasing need for heavy metal detection highlights the advantages of electrochemical methods, which offer high sensitivity and efficiency. Herein mesoporous nitrogen containing carbon (MNC) was utilized for the simultaneous determination of heavy metals using square wave voltammetry technique in the established conditions of a buffer pH of 5.0. MNC demonstrated low detection limits (1, 10 and 50 μM), wide linear ranges (1 μM-6 mM, 10 μM-7 mM and 50 μM-17 mM), and high sensitivities (2.5 μA μM-1 cm-2, 1.03 μA μM-1 cm-2 and 5.14 mA mM-1 cm-2) for, Pb2+, Cd2+ and Cu2+, respectively. Moreover, the reproducibility, and selectivity of the sensor was investigated in the presence of K+, Mg2+, Zn2+, Ni2+, and Fe3+ which are the possible interferents present in water.

Heavy metal detection in industrial waste water using Ficus Benjamina leaf extract–mediated Ag nanoparticles

Heavy metal detection in industrial waste water using Ficus Benjamina leaf extract–mediated Ag nanoparticles