Heavy metals in drinking water: Occurrences, implications, and future needs in developing countries

Fabrication of Boron-Doped Diamond Film Electrode for Detecting Trace Lead Content in Drinking Water

This work aimed to fabricate a boron-doped diamond film electrode for detecting trace amounts of lead in drinking water so as to safeguard it for the public. Available detectors suffer from high costs and complex analytical processes, and commonly used electrodes for electrochemical detectors are subject to a short life, poor stability, and secondary pollution during usage. In this work, a boron-doped diamond (BDD) electrode was prepared on a porous titanium substrate, and the microstructure and electrochemical properties of the BDD electrode were systematically studied. Moreover, the stripping parameters were optimized to obtain a better signal response and determine the detection index. As a result, diamond particles were closely arranged on the surface of the BDD electrode with good phase quality. The electrode showed high electrochemical activity, specific surface area, and low charge transfer resistance, which can accelerate the stripping reaction process of Pb²⁺. The BDD electrode presented a low detection limit of 2.62 ppb for Pb²⁺ under an optimized parameter set with an enrichment time of 150 s and a scanning frequency of 50 Hz. The BDD electrode also has good anti-interference ability. The designed BDD electrode is expected to offer a reliable solution for the dilemma of the availability of metal electrodes and exhibits a good application prospect in the trace monitoring of Pb²⁺ content in drinking water.

A review of simulation experiment techniques used to analyze wildfire effects on water quality and supply

This review addresses the critical knowledge gap of techniques simulating combustion and heating characteristics present in natural wildfires and their use in assessing postfire impacts on water quality and quantity. Our assessment includes both laboratory and plot-scale techniques with burn and rainfall simulation components. Studies included focus on advancing understanding of changes in chemical and physical properties of soil, as well as subsequent runoff changes. Advantages of simulation experiments include: overcoming logistical challenges of collecting in situ wildfire data, reducing the high spatial variability observed in natural settings (i.e., the heterogeneity of burn intensity and the underlying vegetation and soil properties), and controlling the magnitude of key drivers of wildfire impacts. In sum, simulation experiments allow for more direct attribution of water quality and quantity responses to specific drivers than experiments conducted in situ. Drawbacks of simulation techniques include the limitation of observing only local-scale processes, the potential misrepresentation of natural settings (i.e., lack of spatial variability in vegetation, soil structure, burn intensity, etc.), uncertainty introduced through experimental error, and subsequent challenges in upscaling results to larger scales relevant for water management. This review focuses primarily on simulation techniques, with the goal of providing a foundation of knowledge for the design of future simulation experiments.

Co-Effects of Hydrological Conditions and Industrial Activities on the Distribution of Heavy Metal Pollution in Taipu River, China

In Taipu River, after being transformed from a drainage channel to a drinking water supply river in 1995, heavy metals that have accumulated in sediments have become an environmental issue. Herein, we collected sediments of Taipu River in 2018, 2020, and 2021 and analyzed the distribution of Sb, As, Cd, Cu, Pb, Cr, and Zn to identify their sources. The results revealed that the mean concentrations of heavy metals were above the background values, except for Cr and As. During the non-flood season, the midstream of Taipu River becomes a heavy metal hotspot, with their concentrations 2-5 times higher than those in upstream sediment. There were significant correlations (r = 0.79-0.99) among drainage, precipitation and flow rate, which indicated that drainage caused by both the opening of Taipu Gate and precipitation control the flow rate and, then, possibly influenced the distribution of heavy metals. Moreover, three sources (industrial sources, particle deposition sources, and natural sources) were characterized as the determinants for the accumulation of heavy metal by the Positive Matrix Factorization model, with the contribution rates of 41.7%, 32.9%, and 25.4%, respectively. It is recommended that the influence of hydrological conditions and industrial activities should be a key consideration when developing regulations for the management of heavy metals in rivers.

Humic acid-coated hydrated ferric oxides-polymer nanocomposites for heavy metal removal in water

Water pollution by toxic heavy metals poses a threat to the environment and human bodies. Herein, a novel hydrated ferric oxide nanoparticle (HFO) based hybrid adsorbent was fabricated for the removal of toxic Cu(II), Cd(II) and Pb(II) from water. HFOs were immobilized into a porous resin D-201, and then this nanocomposite HFO-D201 was coated with humic acid (HA) to enhance the binding sites of target metals. Both HFOs and HA contribute to the sequestration of heavy metals. The as-synthesized hybrid adsorbent HA-HFO-D201 exhibited excellent performance on the removal of Cu(II), Cd(II), and Pb(II) in a pH range of 3-9, while no Fe leaching was observed. The presence of natural organic matter (20 mg C/L) has limited influences on the adsorption, and more than 85% of the target metals can be removed after treatment. HA-HFO-D201 showed preferable adsorption toward Cu(II) and Pb(II) (1 mg/L) from the background Ca²⁺ solution at much higher concentrations (100 mg/L), while the retention of Cd(II) (1 mg/L) decreased to some extent. Fixed-bed column experiments exhibited that the treatment capacities of HA-HFO-D201 are 90 bed volumes (BV) for Cd(II), 410 BV for Pb(II) and > 800 BV for Cu(II) of simulated contaminated water to meet the WHO drinking water standard. Meanwhile, depleted HA-HFO-D201 can be readily regenerated by a chelating agent Na₂EDTA for repeated use. The hybrid adsorbent HA-HFO-D201 has excellent potential to remove heavy metals in water treatment systems.

Platform Formed from ZIF-8 and DNAzyme: "Turn-On" Fluorescence Assay for Simple, High-Sensitivity, and High-Selectivity Detection of Pb2

Lead contamination has posed a potential threat to the environment and food safety, arousing extensive concern. In this work, we fabricated a novel fluorescent sensing platform based on zeolitic imidazolate framework-8 (ZIF-8) and DNAzyme for monitoring Pb²⁺ in water and fish samples. ZIF-8 was proposed as a fluorescence quencher with the advantages of simple synthesis, low cost, and high quenching efficiency. The Pb²⁺-dependent GR5 DNAzyme containing the large ssDNA loop can be adsorbed onto ZIF-8 accompanied by fluorescence quenching. Upon binding with Pb²⁺, GR5 DNAzyme was activated and cleaved, leading to the release of FAM-labeled 5-base ssDNA, which restored the fluorescence. The "turn-on" assay can detect Pb²⁺ through the one-pot procedure in the range of 0.01-10.0 nM with a detection limit of 7.1 pM. The platform is promising for on-site monitoring of Pb²⁺ owing to the excellent performance of high sensitivity, low background, strong anti-interference ability, and simple operation.

Assessment of physical and chemical properties, health risk of trace metals and quality indices of surface waters of the rivers and lakes of the Kola Peninsula (Murmansk Region, North-West Russia)

The pollution of waterbodies with trace metals is of concern throughout the world due to their high toxicity. One of the main anthropogenic sources of trace metals entering natural waters is the mining and processing of minerals. Intensive development of the mining industry on the Kola Peninsula (the Murmansk region, Russia), exploration and development of new mineral resources have led to a sharp deterioration in the quality of surface waters of rivers and lakes. As a result of anthropogenic impact, accumulation of a wide range of metals (mainly Cu, Ni, Co, Pb, Cd, Mn, Sr, Al and Fe) is observed, as well as significant changes in the physicochemical parameters and radioactive conditions of surface waters. The most polluted waterbodies of the Kola Peninsula are located in the Monchegorsk, Olenegorsk and Apatit regions. Consumption of water from investigated contaminated sources can cause various high risks of human health. The results of this study will provide an informative basis for future risk assessments of the environment and human health, as well as for the development of integrated measures for managing the quality of surface waters of lakes and rivers of the Kola Peninsula.

Water quality evaluation and ecological-health risk assessment on trace elements in surface water of the northeastern Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau is a unique area with water sources for approximately 40 % of the population in the world. Water resources and water quality are closely associated with ecological security and human health. Fifty-one trace elements in surface water samples (n = 40) were measured, and water quality, health and ecological risks were assessed. Trace elements showed significant variations in different surface water bodies in the study area. Concentrations of minor elements were relatively high in saline and salt lakes while those of REEs varied from 0.05 to 33.62 μg/L with an average value of 3.80 μg/L. The Nemerow pollution index (NP) values of trace elements ranged from 0.08 to 3.48, with an average value of 0.36 in rivers, fresh lakes and reservoir water samples; The heavy metal pollution index (HPI) values ranged from 3.70 to 21.18, indicating that most samples were within the critical limit; The heavy metal evaluation index (HEI) values and degree of contamination (DC) values indicated a free pollution status. The water quality index (WQI) values showed that 96 % of the samples belonged to excellent status in rivers, fresh lakes and reservoir water samples. More attention should be given to the Cr, Zn and Hg in the study area according to potential ecological risk assessment. Hazard quotients for residential children in 30 sites exceed 1.0 with maximal value of 10.97, suggesting the high non-carcinogenic risks for children in the study area. U, Zr and Cr for the ingestion pathway, Cr and U for the dermal pathway were primary contributors to the total health risk. Carcinogenic risk values of trace elements for residential and recreational receptors were in the range of 3.20 × 10^-5-7.38 × 10^-3 and 8.62 × 10^-6-3.63 × 10^-3, respectively. The carcinogenic risk values of Cr in surface water were higher than the target risk of 1 × 10^-4, while the carcinogenic risk values of As were below the target risk. The results of this study provided information on trace elements for human health protection and water management in the northeastern Qinghai-Tibet Plateau.

Comprehensive Examination of Cu, Pb, Zn, Fe, Mn and Cd in Lackawanna County Waters, Northeastern Pennsylvania: A Brief Report

Lackawanna, a US county seat in Northeastern Pennsylvania has an estimated population of 216,000 in 2020. Over the years, it has been reported that several bodies of water found within the county have been contaminated with various metals. However, a comprehensive examination of the presence of these metals has not been conducted. The goal of this brief report was to perform a preliminary quantitative determination of the concentration of various metals found in Lackawanna County water sources. The sources analyzed included Lake Scranton, the Lackawanna River, the Griffin Reservoir, and Keyser Creek. Samples were taken from each source and analyses of copper, lead, zinc, iron, manganese, and cadmium using atomic absorption spectroscopy were performed. A copper concentration of 0.100 ppm was found in the Griffin Reservoir, and 0.380 ppm of iron was found in the Lackawanna River. The concentration of copper and iron in the Griffin Reservoir and Lackawanna River, respectively, were determined to be within safe levels according to guidelines set by the US Environmental Protection Agency.

Effect of TiO2 Nanoparticles on Capillary-Driven Flow in Water Nanofilters Based on Chitosan Cellulose and Polyvinylidene Fluoride Nanocomposites: A Theoretical Study

In this study, a novel concept of nanofiltration process of drinking water based on capillary-driven nanofiltration is demonstrated using a bio-based nanocomposites’ nanofilter as free power: a green and sustainable solution. Based on Lifshitz and Young–Laplace theories, we show that the chitosan (CS), cellulose acetate (CLA), and Polyvinylidene fluoride (PVDF) polymer matrixes demonstrate hydrophobic behavior, which leads to the draining of water from nanopores when negative capillary pressure is applied and consequently prevents the capillary-driven nanofiltration process. By incorporating 10%, 20%, and 30% volume fraction of titanium dioxide (TiO₂) nanoparticles (NPs) to the polymers’ matrixes, we demonstrate a wetting conversion from hydrophobic to hydrophilic behavior of these polymer nanocomposites. Subsequently, the threshold volume fraction of the TiO₂ NPs for the conversion from draining (hydrophobic) to filling (hydrophilic) by capillary pressure were found to be equal to 5.1%, 10.9%, and 13.9%, respectively, for CS/TiO₂, CLA/TiO₂, and PVDF/TiO₂ nanocomposites. Then, we demonstrated the negligible effect of the gravity force on capillary rise as well as the capillary-driven flow for nanoscale pore size. For nanofilters with the same effective nanopore radius, porosity, pore shape factor, and tortuosity, results from the modified Lucas–Washburn model show that the capillary rise as well as the capillary-driven water volume increase with increased volume fraction of the TiO₂ NPs for all nanocomposite nanofilter. Interestingly, the capillary-driven water volume was in range (5.26–6.39) L/h·m² with 30% volume fraction of TiO₂ NPs, which support our idea for capillary-driven nanofiltration as zero energy consumption nano-filtration process. Correspondingly, the biodegradable CS/TiO₂ and CLA/TiO₂ nanocomposites nanofilter demonstrate capillary-driven water volume higher, ~1.5 and ~1.2 times, respectively, more than the synthetic PVDF/TiO₂ nanocomposite.

Novel strategies and advancement in reducing heavy metals from the contaminated environment

The most contemporary ecological issues are the dumping of unprocessed factories' effluent. As a result, there is an increasing demand for creative, practical, environmentally acceptable, and inexpensive methodologies to remediate inorganic metals (Hg, Cr, Pb, and Cd) liquidated into the atmosphere, protecting ecosystems. Latest innovations in biological metals have driven natural treatment as a viable substitute for traditional approaches in this area. To eliminate pesticide remains from soil/water sites, technologies such as oxidation, burning, adsorption, and microbial degradation have been established. Bioremediation is a more cost-effective and ecologically responsible means of removing heavy metals than conventional alternatives. As a result, microorganisms have emerged as a necessary component of methyl breakdown and detoxification via metabolic reactions and hereditary characteristics. The utmost operative variant for confiscating substantial metals commencing contaminated soil was A. niger, which had a maximum bioaccumulation efficiency of 98% (Cd) and 43% (Cr). Biosensor bacteria are both environmentally sustainable and cost-effective. As a result, microbes have a range of metal absorption processes that allow them to have higher metal biosorption capabilities. Additionally, the biosorption potential of bacterium, fungus, biofilm, and algae, inherently handled microorganisms that immobilized microbial cells for the elimination of heavy metals, was reviewed in this study. Furthermore, we discuss some of the challenges and opportunities associated with producing effective heavy metal removal techniques, such as those that employ different types of nanoparticles.

Tap Water Consumption Is Associated with Schoolchildren’s Cognitive Deficits in Afghanistan

Environmental influence on intelligence quotient (IQ) is poorly understood in developing countries. We conducted the first cross-sectional investigation to assess the role of socio-economic and environmental factors on schoolchildren’s IQ in Jalalabad, Afghanistan. A representative sample of 245 schoolchildren aged 7–15 was randomly selected in five schools. Children’s records included: non-verbal IQ TONI-1 scale, body mass index, socio-economic status, and further environmental indicators (water supply, proximity to a heavy-traffic road, use of surma traditional cosmetics). The mean age of the children was 11.7 years old (±2.0 years), and 70.2% and 29.8% were male and female, respectively. The children’s mean IQ was 83.8 (±12.6). In total, 37 (14.9%) of the children were overweight, 78 (31.5%) were living below the USD 1.25 poverty line, 133 (53.6%) used tap water supply, 76 (30.6%) used surma, and 166 (66.9%) were exposed to heavy road traffic. The children’s IQ was significantly and independently lowered by tap water use (−3.9; 95% CI [−7.1; −0.6]) and by aging (−1.4; 95% CI [−2.2; −0.6]), as revealed in multivariate analysis, independently of gender, socio-economic status, exposure to heavy road traffic, overweight status, and surma use. Lower IQ among older children is possibly attributed to chronic stress experienced by adolescents due to living conditions in Afghanistan. While using tap water prevents fecal peril, it may expose children to toxic elements such as lead which is known to lower their intellectual development.

Efficient removal of lead ions from aqueous solution by graphene oxide modified polyethersulfone adsorptive mixed matrix membrane

In this study, we report the combined effect of graphene oxide (GO) and polyvinylpyrrolidone (PVP) for the heavy metal removal efficiency of polyethersulfone (PES) membranes. PVP with four different amounts of GO was infused in the membrane matrix by the physical blending method. Characterizations such as porosity, contact angle, water flux and Fourier transform infrared spectroscopy were conducted for all prepared membranes. Viscid behavior of polymer dope solution was examined to understand the phase separation phenomena better. PVP enhanced the GO distribution within the membrane surface to some extent via hydrogen bond. The addition of nanoparticles enhanced the membrane physicochemical properties with water permeation, Pb²⁺ rejection and adsorption capacity. Permeate flux of modified membrane (m4) was found to be 150.21 L/m²h and it is 8.03 times higher than unmodified membrane (m0). Besides, all fabricated membranes were evaluated for Pb²⁺ rejection from synthetic wastewater and rejection % of m4 (80.6%) had increased twofold than m0 (38.9%). Membrane cleaning was performed using different methods and the best results were achieved with a concentration of 0.05 wt% sodium hypochlorite under pH 7 and further reused for the filtration test. Moreover, adsorption isotherm was tested using Freundlich and Langmuir models and the Langmuir model offered the best fitting.

Chemical, radiological and microbiological characterization of a drinking water source: a case study

This study examined water samples from a local stream in Central Serbia, which was consumed as drinking water. The chemical parameters (chemical oxygen demand, pH, total concentration of dissolved substances and electrical conductivity), the concentration of major, trace, and radioactive elements in the water as well as the content of those from the environment, were examined. In addition, the microbiological quality of the water was inspected. The water samples were acidic (pH from 5.27 to 5.69) and chemical oxygen demand ranged in upper permissible limits (up to 6.25 mg O₂ l^-1 (WR)). The concentrations of major, trace and radioactive elements, including radon, were below maximum contaminant levels. The water contained a higher number of total coliform bacteria than it was allowed (˃10 colony forming units (CFU) in 100 ml of water) as well as enterococci and Escherichia coli. The characterization of the isolated bacteria indicated that two isolates demonstrated proteolytic activity, while full antibiotic resistance was not detected. The isolates showed moderate to strong ability to produce biofilm, while the isolates of E. coli were nonpathogenic. The results indicated that examined water samples were not microbiologically and chemically safe, therefore, the usage of analyzed water was not recommended as a water supply. Further research needs to include more frequent monitoring in order to propose measures for the improvement of the water quality and prevention of health risks for consumers.

Multi-component removal of Pb(II), Cd(II), and As(V) over core-shell structured nanoscale zero-valent iron@mesoporous hydrated silica

The application of nanomaterials for the removal of heavy metals has received a great deal of attention because of their high efficiencies in the environment. But it is difficult to remove multiple heavy metals simultaneously with high efficiency and stability. Herein, the core-shell structured nanoscale zero-valent iron (nZVI) encapsulated with mesoporous hydrated silica (nZVI@mSiO₂) were prepared for efficient removal of heavy metals including Pb(II), Cd(II), and metalloid As(V). The material prepared uniformly with a high surface area (147.7 m² g^-1) has a nZVI core with the particle size of 20-60 nm and a modified dendritic mesoporous shell of 19 nm. 0.15 g L^-1 of the optimal material exhibited an extraordinary performance on removing Cd(II) and the maximum adsorption capacity for Pb(II), Cd(II), and As(V) reached 372.2 mg g^-1, 105.2 mg g^-1, and 115.2 mg g^-1 with a pH value at 5.0, respectively. The dissolved iron during the reaction showed that the mesoporous silica (mSiO₂) played an important role in enhancing the stability of nZVI. In addition, the competitive relationship between the coexistence of two heavy metals was discussed and it was found that the removal efficiency of the material for both was improved when Cd(II) and As(V) were removed synergistically.

Removal of lead ions (Pb2+) from water and wastewater: a review on the low-cost adsorbents

The presence of lead compounds in the environment is an issue. In particular, supply water consumption has been reported to be a significant source of human exposure to lead compounds, which can pose an elevated risk to humans. Due to its toxicity, the International Agency for Research on Cancer and the US Environmental Protection Agency (USEPA) have classified lead (Pb) and its compounds as probable human carcinogens. The European Community Directive and World Health Organization have set the maximum acceptable lead limits in tap water as 10 µg/L. The USEPA has a guideline value of 15 µg/L in drinking water. Removal of lead ions from water and wastewater is of great importance from regulatory and health perspectives. To date, several hundred publications have been reported on the removal of lead ions from an aqueous solution. This study reviewed the research findings on the low-cost removal of lead ions using different types of adsorbents. The research achievements to date and the limitations were investigated. Different types of adsorbents were compared with respect to adsorption capacity, removal performances, sorbent dose, optimum pH, temperature, initial concentration, and contact time. The best adsorbents and the scopes of improvements were identified. The adsorption capacity of natural materials, industrial byproducts, agricultural waste, forest waste, and biotechnology-based adsorbents were in the ranges of 0.8-333.3 mg/g, 2.5-524.0 mg/g, 0.7-2079 mg/g, 0.4-769.2 mg/g, and 7.6-526.0 mg/g, respectively. The removal efficiency for these adsorbents was in the range of 13.6-100%. Future research to improve these adsorbents might assist in developing low-cost adsorbents for mass-scale applications.

Hyperspectral sensing of heavy metals in soil by integrating AI and UAV technology

Given the limitation of conventional soil pollution monitoring through mapping which is a costly, time-consuming work, the study aims to establish an image recognition model to identify the source of pollution automatically. The study choses a contaminated land and then use a non-destructive instrument that can quickly and effectively measure the content of heavy metals. A two concentration prediction models of Ni, Cu, Zn, Cr, Pb, As, Cd, and Hg using hyperspectral imaging were developed, Decision Tree and Back Propagation Neural Network, in combination of particle swarm optimization employed for optimization algorithm. As a result, random forest is more accurate than the forecast result of back propagation neural network. This study has established an excellent Cu and Cr model, which can accurately capture the pollution source. In addition, through aerial photographs, we also found that there were also high pollution reactions on the banks of the river. The developed model is beneficial for high pollution areas which can be quickly found, thereby following investigation and remediation work can be carried out with less time and cost consuming comparing with the conventional soil monitoring.

Effects of a soil collembolan on the growth and metal uptake of a hyperaccumulator: Modification of root morphology and the expression of plant defense genes

Soil collembolans live in close proximity to plant roots and may have a role in the phytoextraction of potentially toxic metals from contaminated soils but the underlying mechanisms remain poorly investigated. We hypothesize that soil collembolans may change the root morphology of hyperaccumulators by regulating plant physiological characteristics. Here, a pot experiment was conducted in which a cadmium (Cd) and zinc (Zn) hyperaccumulator (Sedum plumbizincicola) was grown with or without a collembolan (Folsomia candida), and plant transcriptome and hormones as well as the root characteristics of S. plumbizincicola were analyzed. F. candida promoted the growth and Cd/Zn uptake of S. plumbizincicola, the root and shoot biomass increasing by 53.3 and 34.4%, and the uptake of Cd and Zn in roots increased by 83.2 and 65.4%, respectively. Plant root morphology, total root length, root tip number and lateral root number increased significantly by 40.7, 37.2 and 33.8%, respectively, with the addition of F. candida. Transcriptome analysis reveals that the expression levels of defense-related genes in S. plumbizincicola were significantly up-regulated. In addition, the defensive plant hormones, i.e. salicylic acid in the roots, increased significantly by 338%. These results suggest that the plant in defense of the action of F. candida regulated the expression of the corresponding genes and increased the defensive plant hormones, thus modifying root morphology and plant performance. Overall, this study highlights the importance of the regulation by collembolans of plant growth and metal uptake by interaction with hyperaccumulator roots.

Plot-on-demand integrated paper-based sensors for drop-volume voltammetric monitoring of Pb(II) and Cd(II) using a bismuth nanoparticle-modified electrode

The fabrication of fully ink-drawn fluidic electrochemical paper-based analytical devices (ePADs) is reported for the determination of trace Pb(II) and Cd(II) by differential pulse anodic stripping voltammetry (DPASV). The fluidic pattern was formed on the paper substrate using an inexpensive computer-controlled x-y plotter and a commercial hydrophobic marker pen. Then, electrodes were deposited on the devices using a second x-y plotting step with a commercial technical pen filled with a graphite-based conductive ink prepared in house. The fabrication parameters of the ePADs were studied by cyclic voltammetry using the ferro/ferri couple as a probe and by scanning electron microscopy. The ePADs, featuring a bismuth nanoparticle-modified working electrode, were applied to the determination of Pb(II) and Cd(II) by DPASV. The chemical and instrumental conditions were studied. The limits of detection were 3.1 μg L^-1 for Cd(II) and 4.5 μg L^-1 for Pb(II) whereas the between-device reproducibility (expressed as the % relative standard deviation of the response at 6 different ePADs) was < 14%. Each ePAD requires 120 s to fabricate and costs less than 0.15 € in terms of consumables. The ePADs are suitable for the on-site determination of Pb(II) and Cd(II) in environmental and food samples.

Occurrence of Potentially Toxic Elements in Bottled Drinking Water-Carcinogenic and Non-Carcinogenic Risks Assessment in Adults via Ingestion

The presence of potentially toxic elements in drinking water can be dangerous for human health because of their bioaccumulation and toxicity, which is a huge concern for many researchers. In the case of bottled water, the exposure to toxic elements is achieved, especially by ingestion, leading to disorders of important functions of the human body. The aim of this study was the detection of some potentially toxic elements, from 50 samples of bottled drinking water, available on the Romanian market. Based on obtained concentrations, an assessment of the carcinogenic and non-carcinogenic health risk was performed. The concentrations of potentially toxic elements analyzed were below the maximum allowable limits, for all contaminants, excluding Pb and Fe. Moreover, the results of total risk via ingestion, showed that 30% of samples had an Hazard Quotient (HQ) < 1, and 70% had an HQ > 1; which implies a potential risk following the consumption of those samples. Concerning total cancer risk, 28% of the samples are in the acceptable level, while 72% of the samples are considered harmful and can lead to a type of cancer after repeated exposure. The study concluded that long term use of bottled water of poor quality may pose a hazard to human health; it is helpful for inhabitants to avoid ingestion of contaminated water.

Liquid-liquid extraction of copper(II), zinc(II), cadmium(II), and lead(II) from aqueous solution and sewage effluent using phenoxy-amino ligands

The phenoxy-amino ligands 2-(((2-(diethylamino)ethyl)amino)methyl)phenol (L1) and 2-(((2-mercaptoethyl)amino)methyl)-phenol (L2) were studied as model chelating agents for liquid-liquid extraction of copper(II), zinc(II), cadmium(II), and lead(II) cations from water using dichloromethane-water biphasic system. The relative affinities of these chelating ligands for copper(II), zinc(II), cadmium(II), and lead(II) by liquid-liquid extraction were found to be in the order copper(II)> zinc(II) > cadmium(II) > lead(II). The ligands L1 and L2 showed binding efficiencies ranging from 78%-97% for copper(II), 75%-91% for zinc(II), 76%-92% for cadmium(II), and 59%-67% for lead(II). The extraction protocol was successfully applied to sewage effluent.

Six fruit and vegetable peel beads for the simultaneous removal of heavy metals by biosorption

In this study, a comparison between the biosorption performance of six fruit and vegetable peels, namely kiwifruit (KP), apple, banana, cucumber, orange and potato immobilized on sodium alginate beads has been made. Inductively coupled plasma coupled with mass spectroscopy was used for measuring the concentration of metal ions in solution before and after biosorption. A range of kinetic models were also applied to the biosorption batch data. The results showed that biosorption percentage of the ions were different on the various beads. For example, the decreasing order of biosorption by one KP bead at equilibrium was Cd > Cu > Hg > Ni > Pb > Cr > As, with approximately 92%, 84%, 80%, 75%, 67%, 34%, and 17% simultaneous removal of ions, respectively. The fastest biosorption was seen with Cd and Pb, as both reached equilibrium by 24 h. Equilibrium time of all other ions occurred by 48 h. While all beads in their unmodified form were suitable for the removal of divalent cations, KP bead showed significantly higher removal of the anion hexavalent Cr. Biosorption of Cd, Hg and Ni was limited by both pseudo-first order and pseudo-second order reaction rates. For Cr and Cu, the reaction was controlled by film diffusion and pseudo-first order rates. At a higher solution concentration, the preference of ions biosorbed as well as their percentage removed changed. Overall, the results indicated that KP beads show promise as a cost-effective method for removing toxic ions by biosorption, especially hexavalent chromium from drinking water.

A facile modification of cation exchange resin by nano-sized goethite for enhanced Cr(VI) removal from water

A novel macroporous strong acidic cation exchange resin (D001) modified by nano-sized goethite (nFeOOH@D001) was fabricated by using a facile ethanol dispersion and impregnation method, and its efficiency for Cr(VI) removal was tested thereafter. Due to the dispersing effect of ethanol, FeOOH particles of 20-150 nm were coated on the D001 surfaces. The nFeOOH@D001 obtained a Cr(VI) removal efficiency and capacity of 80.2% and 7.4 mg/g respectively, 5 times and 8 times higher than that of the pristine D001. The Cr(VI) removal by nFeOOH@D001 followed the pseudo second-order kinetics and the Langmuir adsorption model. Column experiments also demonstrated that the nFeOOH@D001 exhibited a much better ability to remove Cr(VI) as compared to the D001. Additionally, the nFeOOH@D001 showed a potential for reusability and renewability. The adsorbed nFeOOH@D001 could be easily desorbed by 0.1 M acetic acid and a reuse efficiency of 92.7% could be maintained after 4 desorption-adsorption cycles. The used nFeOOH@D001 could be eluted by 0.1 M HCl to remove nFeOOH, and the renewed D001 could be recoated by nFeOOH and achieved a regeneration rate of 97.8% for Cr(VI) removal. The above results indicated that nano-sized goethite modification is a promising method to endow D001 with the ability to remove Cr(VI) from water.

Natural polyphenol-based nanoengineering of collagen-constructed hemoperfusion adsorbent for the excretion of heavy metals

Designing a hemoperfusion adsorbent for the excretion therapy of toxic heavy metals still remains a great challenge due to the biosafety risks of non-biological materials and the desired highly efficient removal capacity. Herein, inspired from the homeostasis mechanism of plants, natural polyphenols are integrated with collagen matrix to construct a polyphenol-functionalized collagen-based artificial liver (PAL) for heavy metals excretion and free radicals scavenging therapy. PAL presents high adsorption capacities for Cu²⁺, Pb²⁺, and UO₂²⁺ ions, up to 76.98 μmol g^-1, 106.70 μmol g^-1, and 252.48 μmol g^-1, respectively. Remarkably, PAL possesses a high binding affinity for UO₂²⁺, Pb²⁺, and Cu²⁺ ions even in the complex serum environment with the presence of biologically-relevant ions (e.g., Mg²⁺, Ca²⁺ ions). Low hemolysis ratio (1.77%), high cell viability (> 85%), high plasma recalcification time (17.4 min), and low protein adsorption (1.02 μmol g^-1) indicate outstanding biocompatibility of this material. This natural polyphenol/collagen-based fully bio-derived hemoperfusion adsorbent provides a novel and potentially applicable strategy for constructing a hemoperfusion adsorbent for heavy metal ions excretion therapy with efficiency and biosafety.

View of Saudi Arabia Strategy for Water Resources Management at Bishah, Aseer Southern Region Water Assessment

Water quality management is critical for the preservation of freshwater resources in semi-arid and arid areas, which are necessary for long-term development. Local authorities and water resource managers can allocate resources for potable or agricultural needs based on the quality of water in various places. A total of 14 water samples were collected and examined in this study. Microbiological, chemical and physical analyses were considered as important indicators for assessing water quality. Physical, chemical, and microbiological data were measured and evaluated as essential markers for determining water quality. A comparison was made between these characteristics and the King Saudi Water Standard (GSO149/2014). According to the findings, results of infiltration pond and Tabla Dam manifest the anthropogenic activities and natural influences of the greatest impact on water quality. Therefore, a reliable assessment approach for assessing water quality is very important for decision makers and for constructing sustainable development plans.

Identification of heavy metal ions from aqueous environment through gold, Silver and Copper Nanoparticles: An excellent colorimetric approach

Heavy metal pollution has become a severe threat to human health and the environment for many years. Their extensive release can severely damage the environment and promote the generation of many harmful diseases of public health concerns. These toxic heavy metals can cause many health problems such as brain damage, kidney failure, immune system disorder, muscle weakness, paralysis of the limbs, cardio complaint, nervous system. For many years, researchers focus on developing specific reliable analytical methods for the determination of heavy metal ions and preventing their acute toxicity to a significant extent. The modern researchers intended to utilize efficient and discerning materials, e.g. nanomaterials, especially the metal nanoparticles to detect heavy metal ions from different real sources rapidly. The metal nanoparticles have been broadly utilized as a sensing material for the colorimetric detection of toxic metal ions. The metal nanoparticles such as Gold (Au), Silver (Ag), and Copper (Cu) exhibited localized plasmon surface resonance (LPSR) properties which adds an outstanding contribution to the colorimetric sensing field. Though, the stability of metal nanoparticles was major issue to be exploited colorimetric sensing of heavy emtal ions, but from last decade different capping and stabilizing agents such as amino acids, vitmains, acids and ploymers were used to functionalize the metal surface of metal nanoparticles. These capping agents prevent the agglomeration of nanoparticles and make them more active for prolong period of time. This review covers a comprehensive work carried out for colorimetric detection of heavy metals based on metal nanoparticles from the year 2014 to onwards.

Serum Elemental Analysis of Type 2 Diabetes Patients Using SRXRF

A total of 158 serum samples of newly diagnosed type 2 diabetes patients and control subjects were analyzed using Synchrotron Radiation X-ray Fluorescence (SRXRF) technique. The microprobe XRF beam line-16 of Indus-2 synchrotron radiation facility at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore, India, was used to identify and quantify the elements K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, and Pb. A significant decrease in the mean concentrations of K, Ca, Ti, Cr, Mn, Ni, Zn, and As and an increase in the concentrations of V, Fe, Co, Cu, Se, and Pb were observed in the serum samples of the patient group when compared to the control group. It is hypothesized that the observed alterations in the elemental concentrations might have led to ineffective uptake of insulin and have interfered with glucose homeostasis by either directly or indirectly causing oxidative stress.

Superparamagnetic Iron Oxide Nanoparticle Nanodevices Based on Fe3O4 Coated by Megluminic Ligands for the Adsorption of Metal Anions from Water

The uptake ability toward arsenic(V), chromium(VI), and boron(III) ions of ad hoc functionalized magnetic nanostructured devices has been investigated. To this purpose, ligands based on meglumine have been synthesized and used to coat magnetite nanoparticles (Fe₃O₄) obtained by the co-precipitation methodology. The as-prepared hybrid material was characterized by infrared spectroscopy (IR), X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy combined with energy-dispersive X-ray analysis. Moreover, its magnetic hysteresis properties were measured to evaluate its magnetic properties, and the adsorption kinetics and isothermal models were applied to discern between the different adsorption phenomena. Specifically, the better fitting was observed by the Langmuir isotherm model for all metal ions tested, highlighting a higher uptake in arsenic (28.2 mg/g), chromium (12.3 mg/g), and boron (23.7 mg/g) sorption values if compared with other magnetic nanostructured materials. After adsorption, an external magnetic stimulus can be used to efficiently remove nanomaterials from the water. Finally the nanomaterial can be reused up to five cycles and regenerated for another three cycles.

Tissue-specific distribution and bioaccumulation pattern of trace metals in fish species from the heavily sediment-laden Yellow River, China

The Yellow River is one of the largest contributors to the global riverine sediment flux from the land to the ocean. Tissue-specific bioaccumulation of trace metals in fish from heavily sediment-laden rivers remains unclear to date. The concentrations and distributions of trace metals in water, suspended matters, sediments, and various fish tissues were investigated in the mainstem of the Yellow River were investigated. The concentrations of most metals in abiotic media were high in the Gan-Ning-Meng of upstream and downstream segments, and were highest in fine-sized suspended matters. The highest concentrations of most metals were in the gill and liver, followed by the gonad, and lowest in the muscle, and there were a significant overall differences among the tissues. The concentrations of metals in some tissues (e.g., muscle and gill) significantly differed among regions and feeding habits. The highest values of the bioaccumulation factor for suspended matters (BF_SPM) were observed in the midstream region (e.g., reaching to 19.0 for Se in the liver). This was determined by metal type and tissue specificity, food composition, and concentration of metals in abiotic media. The results highlight the significance of suspended matters for the distribution of trace metals in abiotic and biotic media.

Bottled water quality ranking via the multiple-criteria decision-making process: a case study of two-stage fuzzy AHP and TOPSIS

Access to healthy drinking water is vital to human health and development. Bottled water consumption has been on the rise in recent years. As several chemical and bacteriological parameters affect bottled water quality, it is difficult to choose the highest-quality bottled water. Numerous studies have proposed the use of multiple-criteria decision-making (MCDM) methods to overcome this problem. Herein, the two-stage fuzzy analytic hierarchy process (FAHP) and technique for order preference by similarity to ideal solution (TOPSIS) method were adopted to rank different brands of bottled water. The FAHP approach allows working at the intervals of judgment rather than absolute values. TOPSIS is a technique for ordering performance based on its similarity to the ideal solution. An expert panel selected and classified the criteria and sub-criteria. A pairwise comparison questionnaire was then developed, and the weights of the criteria and sub-criteria were assigned by water quality experts. The data on the quality of different brands of water were collected from the Iranian bottled water database. The final data analysis and weight determination of each parameter were performed in Excel and R software Programs. Finally, the CCi (value of closeness coefficient) and rank of 71 bottled water brands were calculated, and the best brand was introduced. Among the selected criteria, carcinogenic chemical compounds with the weight of 0.368 were the most important compound in ranking bottled water brands, followed by bacteriologic, pathogenic chemical compounds, chemical compounds important in terms of toxicity, nutritious chemical compounds with a low toxicity level, chemical compounds related to esthetic effects, and chemical compounds without health effects, respectively.

Seasonal variations of toxic metal(loid)s in groundwater collected from an intensive agricultural area in northwestern Turkey and associated health risk assessment

İpsala district located in the northwest of Turkey is an intensive agricultural area, where paddy cultivation has been carried out for more than 50 years. The main source for drinking water in the area is groundwater. Since large amounts of agrochemicals are applied to the paddy fields, groundwater in the study area can be contaminated with toxic metal (loid)s (TMs). In this study, levels of eight TMs in the drinking water samples taken from the district and its 22 villages in the dry and wet seasons were measured and compared with drinking water quality guidelines. In addition, non-carcinogenic and carcinogenic health risks, and pollution status of TMs were assessed. The mean values of Cd, Ni, Cu, Zn, Mn, Pb, As and Cr in both seasons were below the drinking water limits. High clay content and low infiltration rate of the soils in the study area may have caused low TM concentrations. The TMs levels were higher in the wet season due to high rainfall intensity. Metal pollution indices indicated that groundwater quality is suitable for potable uses. All hazard quotient and hazard index results for children and adults in both seasons were lower than the acceptable risk level of 1. Carcinogenic risk results of As and Cr in both seasons were within or below the acceptable risk range. These findings revealed that the TMs in the drinking water would not pose health risks to the local residents.

Functionalized dual modification of covalent organic framework for efficient and rapid trace heavy metals removal from drinking water

A key challenge in trace heavy metals removal from drinking water by adsorption technology is to achieve high adsorption capacity and rapid uptake speed of adsorbent. Herein, we report a functionalized double modified covalent organic framework (DMTD-COF-SH) bearing high-density sulfur and nitrogen chelating groups provided simultaneously by 2,5-dimercapto-1,3,4-thiadiazole (DMTD) and 1,2-ethanedithiol, which was prepared via a facile one-pot thiol-ene "click" reaction. PXRD, FTIR, XPS, SEM, BET and ¹³C MAS NMR confirmed their successful graft, and DMTD was found to be more easily grafted on the COF surface layer than 1,2-ethanedithiol. The as-prepared DMTD-COF-SH showed remarkable adsorption capacity and ultrafast uptake dynamics to trace heavy metals owing to the synergistic effects resulting from densely populated sulfur and nitrogen chelating groups within ordered COF mesopores and at the COF surface. On the basis of the drinking water treatment units standard NSF/ANSI 53-2020, when the adsorbent dosage was 10 mg/30 mL and 20 mg L^-1 calcium ions coexisted, the lead concentration decreased from initial 150 μg L^-1 to 2.89 μg L^-1 within 10 s, far below the allowable limit of world health organization (WHO) drinking water standard (10 μg L^-1), and the maximum adsorption capacity meeting the standard attained 14.22 mg g^-1. The adsorbent also exhibited excellent stability, wide applicable pH range and outstanding adsorption performance for coexisting trace lead, mercury, cadmium, chromium (VI) and copper in tap water, indicating that the DMTD-COF-SH material has excellent application prospect for trace heavy metals removal from drinking water.

Modified Oyster Waste Shells as a Value-Added Sorbent for Lead Removal from Water

Used oyster shells are considered a waste product of the seafood industry. Herein, we hypothesize that oyster shells can be used as a raw ingredient to synthesize effective sorbents. This study investigated the lead sorption ability of modified oyster shells [phosphoric-acid treated oyster shell (POS) and oyster shells with phosphoric acid (OS + P)] from water. XRD confirmed the presence of calcium phosphate. Lead removal efficiency as a function of sorbent type was as follows: OS + P > POS > OS. Sorption was quantified effectively using Freundlich isotherms with correlation coefficients ranging from 0.98 to 0.99. The Freundlich parameter values of K_f and n indicate that POS and OS + P exhibit stronger lead sorption than OS. These results indicate that modified oyster shells with OS + P and POS could be effective sorbents for lead removal from water. Kinetic models were well described by a pseudo-second-order rate constant for all the sorbents.

Model-based Application for Adsorption of Lead (II) from Aqueous Solution using Low-cost Jute Stick Derived Activated Carbon

Background:

Removal of lead (II) ions from supply water using an inexpensive adsorbent is essential. It is recommended that low-cost adsorbents are developed to effectively remove lead (II) ions from aqueous solutions. The aim of the study is to develop and validate models for predicting the performance of carboxylated jute stick derived activated carbon (JSAC-COOH) in removing lead (II) ions from aqueous solution, which can assist the water supply authorities in supplying lead (II) free drinking water to the communities at a low-cost.

Methods:

Controlled laboratory experiments were conducted following the statistical “Design of Experiments” through varying the factors affecting the performance of JSAC-COOH in removing lead (II) ions. The performance of JSACCOOH was investigated for different concentrations of lead (II) ions (range: 50 - 500 mg/L) at variable experimental conditions (temperature: 15°C and 27°C; pH: 4.0 and 7.0) and time (1, 10, 30 and 60 min). Several models (Linear and non-linear) were investigated and validated for predicting the concentrations of lead (II) ions in aqueous solution.

Results:

The prepared JSAC-COOH had a surface area of 615.3 m2 /g. In 60 min, up to 99.8% removal of lead (II) ions was achieved. Few models showed very good to excellent predictive capabilities with coefficients of determination in the range of 0.85–0.95. The model validation experiments showed the correlation coefficients in the range of 0.84 – 0.98.

Conclusion:

The models have the capabilities to reasonably predict the final concentrations of lead (II) ions, which can be used in controlling the effluent lead (II) ion concentrations. The proposed adsorbent is likely to be low-cost as it was developed using the commonly available agricultural byproduct.

Field study on the characteristics of scales in damaged multi-material water supply pipelines: Insights into heavy metal and biological stability

Microbial corrosion and heavy metal accumulation in metal water supply pipelines aggravate scale formation and may result in pipeline leakage or bursting events. To better understand the corrosion and corrosion products in the damaged pipes, deposits excavated from three damaged pipes after 22-26 year service periods were analyzed. Using a combination of advanced micro-mineral techniques and 16S rRNA high-throughput sequencing, the micromorphology, chemical composition, and bacterial community were investigated systematically. Unlined pipe wall scales ruptured while lined pipes leaked due to joint scales. Dendrogram correlation results demonstrated that V/As, Al/Pb, and Cr/Mn clusters exhibited co-adsorption and co-precipitation characteristics. FTIR and XRD analysis detected the presence of γ-FeOOH, α-FeOOH in loose scales, and Fe₃O₄ in rigid scales. Scales were colonized by various corrosion bacteria, with sulfate reducing bacteria and ammonia producing bacteria being dominant in the scales of anticorrosive and non-corrosive pipe, respectively. Tl, Ca, Al, and Pb exhibited an extremely positive correlation with Rhodocyclaceae, Ferritrophicum, Thermodesulfovibrionia, and Clostridiaceae. Al and V presented a potential Hazard Quotient risk to consumers, while Cd was potentially bioavailable in all inner scales. Overall, this study provides valuable information for the effective management and avoidance of corrosion-induced pipeline damage and heavy metal release.

Photocatalytic materials immobilized on recycled supports and their role in the degradation of water contaminants: A timely review

Global concern about environmental pollution has increased in recent times due to the cumulative harmful impact on the human health occasioned by the diverse toxic substances released into the environment. Water reduced availability for human consumption and its pollution have been paid so much attention due to their relevance in agricultural and industrial activities. In this context, the advanced oxidation processes for removing contaminants from water, more specifically photocatalytic processes, have displayed their usefulness due to features such as easy application, low-cost, harmless effects and sustainable decontamination efficiency. This timely review is centered on worldwide studies, where efforts aimed at employing recycled materials as supports for purification applications such as the removal of different contaminants (dyes, pharmaceutical contaminants, and heavy metals) dissolved in aqueous environments have been reported. Materials like polyethylene terephthalic (PET), polystyrene (PS), disposal textile fabrics, newspapers, aluminum soda cans, rubber, waste electronic and electric components and used batteries have been employed either as supports for immobilizing catalysts or as photocatalysts. The present work offers a discussion of the ways through which photocatalytic composites have been immobilized or produced, employed characterization techniques, removal efficiencies achieved during photocatalytic degradation and possible degradation mechanism of pollutants; not only the highlights of all these studies are discussed, but also paths for future research works that could help improve the reported results are suggested. These new practical tools stand as novel sustainable strategies for the removal of emerging contaminants reusing waste flexible materials.

Naturally occurring potentially toxic elements in groundwater from the volcanic landscape around Mount Meru, Arusha, Tanzania and their potential health hazard

The population of the semi-arid areas of the countries in the East African Rift Valley (EARV) is faced with serious problems associated with the availability and the quality of the drinking water. In these areas, the drinking water supply largely relies on groundwater characterised by elevated fluoride concentration (> 1.5 mg/L), resulting from interactions with the surrounding alkaline volcanic rocks. This geochemical anomaly is often associated with the presence of other naturally occurring potentially toxic elements (PTEs), such as As, Mo, U, V, which are known to cause adverse effects on human health. This study reports on the occurrence of such PTEs in the groundwater on the populated flanks of Mt. Meru, an active volcano situated in the EARV. Our results show that the majority of analysed PTEs (Al, As, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Se, Sr, Pb, and Zn) are within the acceptable limits for drinking purpose in samples collected from wells, springs and tap systems, suggesting that there is no immediate health risk associated with these PTEs. However, some of the samples were found to exceed the WHO tolerance limit for U (> 30 μg/L) and Mo (> 70 μg/L). The sample analysis also revealed that in some of the collected samples, the concentrations of total dissolved solids, Na⁺ and K⁺ exceed the permissible limits. The concerning levels of major parameters and PTEs were found to be associated with areas covered with debris avalanche deposits on the northeast flank, and volcanic ash and alluvial deposits on the southwest flanks of the volcano. The study highlights the need to extend the range of elements monitored in the regional groundwater and make a more routine measurement of PTEs to ensure drinking water safety and effective water management measures.

Engineered macroalgal and microalgal adsorbents: Synthesis routes and adsorptive performance on hazardous water contaminants

Colourants, micropollutants and heavy metals are regarded as the most notorious hazardous contaminants found in rivers, oceans and sewage treatment plants, with detrimental impacts on human health and environment. In recent development, algal biomass showed great potential for the synthesis of engineered algal adsorbents suitable for the adsorptive management of various pollutants. This review presents comprehensive investigations on the engineered synthesis routes focusing mainly on mechanical, thermochemical and activation processes to produce algal adsorbents. The adsorptive performances of engineered algal adsorbents are assessed in accordance with different categories of hazardous pollutants as well as in terms of their experimental and modelled adsorption capacities. Due to the unique physicochemical properties of macroalgae and microalgae in their adsorbent forms, the adsorption of hazardous pollutants was found to be highly effective, which involved different mechanisms such as physisorption, chemisorption, ion-exchange, complexation and others depending on the types of pollutants. Overall, both macroalgae and microalgae not only can be tailored into different forms of adsorbents based on the applications, their adsorption capacities are also far more superior compared to the conventional adsorbents.

Associations of multiple plasma metals with the risk of metabolic syndrome: A cross-sectional study in the mid-aged and older population of China

BACKGROUND

Metal exposures have been reported to be related to the progress of metabolic syndrome (MetS), however, the currents results were still controversial, and the evidence about the effect of multi-metal exposure on MetS were limited. In this study, we intended to evaluate the relationships between metal mixture exposure and the prevalence of MetS in a mid-aged and older population of China.

METHODS

The plasma levels of 13 metals (aluminum, magnesium, calcium, iron, manganese, cobalt, copper, arsenic, zinc, selenium, cadmium, molybdenum and thallium) were detected by inductively coupled plasma mass spectrometry (ICP-MS) in 1277 adults recruited from the Eighth Affiliated Hospital of Sun Yat-Sen University (Shenzhen, China). Logistic regression, the adaptive least absolute shrinkage and selectionator operator (LASSO) penalized regression analysis and restricted cubic spline (RCS) analysis were used to explore the associations and dose-response relationships of plasma metals with MetS. To evaluate the cumulative effect of metals, the Bayesian Kernel Machine Regression (BKMR) model was applied.

RESULTS

The concentrations of magnesium and molybdenum were lower in the MetS group (p < 0.05). In the single-metal model, the adjusted ORs (95%CI) in the highest quartiles were 0.44 (0.35, 0.76) for magnesium and 0.30 (0.17, 0.51) for molybdenum compared with the lowest quartile. The negative associations and dose-dependent relationships of magnesium and molybdenum with MetS were further validated by the stepwise model, adaptive LASSO penalized regression and RCS analysis. The BKMR models showed that the metal mixture were associated with decreased MetS when the chemical mixtures were≥ 25th percentile compared to their medians, and Mg, Mo were the major contributors to the combined effect. Moreover, concentrations of magnesium were significantly related to blood glucose, and molybdenum was related with BMI, blood glucose and blood pressure.

CONCLUSIONS

Elevated levels of plasma magnesium and molybdenum were associated with decreased prevalence of MetS. Further investigations in larger perspective cohorts are needed to confirm our findings.

Drinking water elements constituent profiles and health risk assessment in Wuxi, China

Water elements pollution has attracted public attention globally. Wuxi is located in East China, and its water source, Taihu Lake, has been severely polluted since 2007. Studies of elemental pollution profiles have yet to be conducted in this area. In this study, 56 water samples were collected in 2018, and 33 elements were determined using inductively coupled plasma-mass spectrometry (ICP-MS). The results showed that the levels of 33 elements ranged from 1.35 × 10^-3 μg/L(Tl) to 101 mg/L(Ca), with Sr, Al, Fe, B, Ti, Ba, and Zn levels being relatively higher. A comprehensive literature review showed spatial distribution of conspicuous elements in drinking water worldwide. Meanwhile, Monte Carlo simulations were applied to evaluate exposure health risks. The total hazard index(HI) for 14 non-carcinogens and the average incremental lifetime cancer risk (ILCR) of As and Pb exposure through drinking water were found acceptable. Sensitivity analyses suggested that Sb and As in the drinking water represent an increasing risk to human health. The results of this study provide key data on local metal pollution characteristics, help identify potential risk factors, and contribute to the development of effective environmental management policies for Taihu Lake.

Invasive plants as biosorbents for environmental remediation: a review

Water contamination is an environmental burden for the next generations, calling for advanced methods such as adsorption to remove pollutants. For instance, unwanted biowaste and invasive plants can be converted into biosorbents for environmental remediation. This would partly solve the negative effects of invasive plants, estimated at 120 billion dollars in the USA. Here we review the distribution, impact, and use of invasive plants for water treatment, with emphasis on the preparation of biosorbents and removal of pollutants such as cadmium, lead, copper, zinc, nickel, mercury, chromate, synthetic dyes, and fossil fuels. Those biosorbents can remove 90-99% heavy metals from aqueous solutions. High adsorption capacities of 476.190 mg/g for synthetic dyes and 211 g/g for diesel oils have been observed. We also discuss the regeneration of these biosorbents.

A Comprehensive Review of Minerals, Trace Elements, and Heavy Metals in Saffron

Saffron is one of the most expensive spices in the world, and its popularity as a tasty food additive is spreading rapidly through many cultures and cuisines. Minerals and heavy metals are minor components found in saffron, which play a key role in the identification of the geographical origin, quality control, and food traceability, while they also affect human health. The chemical elements in saffron are measured using various analytical methods, such as techniques based on spectrometry or spectroscopy, including atomic emission spectrometry, atomic absorption spectrometry, inductively coupled plasma optical emission spectrometry, and inductively coupled plasma mass spectrometry. The present study aimed to review the published articles about heavy metals and minerals in saffron across the world. To date, 64 chemical elements have been found in different types of saffron, which could be divided into three groups of macro-elements, trace elements, and heavy metals (trace elements with a lower gravity/greater than five times that of water and other inorganic sources). Furthermore, the chemical elements in the saffron samples of different countries have a wide range of concentrations. These differences may be affected by geographical condition such as physicochemical properties of the soil, weather and other environmental conditions like saffron cultivation and its genotype.

Assessment of heavy metal pollution transfer and human exposure risks from the consumption of chicken grown in mining-surrounding areas

The purpose of this study was to assess heavy metal contamination in soil, plants, earthworms, and chicken in farmlands adjacent to an old mining site and to evaluate the potential exposure risks to humans through the consumption of chicken. For this purpose, soil, earthworms, plant, chickens, and eggs were sampled from 5 sites following a gradient of contamination. All samples were analyzed for heavy metals (Pb, Cd, Cu, and Zn). A food chain model was used in order to characterize heavy metal transfer between soil-plant-earthworm and chicken organs. Furthermore, target hazard quotient (THQ), estimated daily intake (EDI), and hazard index (HI) were employed to assess human health risks posed by heavy metal contamination. Despite the higher level of Pb, our data related to the calculation of EDI and THQ suggested that local consumers are more at risk of Cd contamination. The calculated HI showed values ranging from 2.58 to 4.74 for adults, and up to 12.34 for children, indicating a considerable risk to the health of local inhabitants, especially children. This study highlighted the crucial role of diets based on chickens grown in contaminated areas, on health risks especially for children.

Optimization of toxic metal adsorption on DEA-calix[4]arene appended silica resin using a central composite design

An assessment of central composite design (CCD) for the optimization of the adsorption of toxic metal ions using a DEA-calix[4]arene (DEA-C4) based silica resin.

Adsorption of Chromium (VI) by Cu (I)-MOF in Water: Optimization, Kinetics, and Thermodynamics

To investigate the adsorption behavior of Cu (I)-MOF material for chromium (VI) in water, the parameters of influencing adsorption were optimized and found as follows: the optimal pH was 6 for the adsorption of Cr (VI) by the Cu (I)-MOF, the optimal amount of adsorbent was 0.45 g·L−1, and the adsorption saturation time was within 180 min. Subsequently, the kinetics results were fitted by four models such as pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. Among them, the adsorption of chromium (VI) was more inclined to the pseudo-first-order model (Radj2 = 0.9230). Then, the isotherm data were fitted by Langmuir and Freundlich models. The results indicated that Langmuir isotherm was the excellent match model (Radj2 = 0.9827). It belongs to a monolayer adsorption, and the maximum adsorption capacity was 95.92 mg·g−1. Subsequently, the thermodynamic parameters of the adsorption were calculated as follows: enthalpy change (ΔHθ) was −8.583 kJ·mol−1, entropy change (ΔSθ) was −8.243 J·mol−1 K−1, and the Gibbs function change (ΔGθ) was less than zero in the temperature range of 288–328 K, indicating that the reaction was spontaneous. Finally, both the spectra of infrared and XPS supported the adsorption mechanism that belonged the ion exchange. The spectra of XRD and SEM images shown that the structure of Cu (I)-MOF remained stable for at least 3 cycles. In conclusion, Cu (I)-MOF material has a high adsorption capacity, good water stability, low cost, and easy to prepare in large quantities in practical application. It will be a promising adsorbent for the removal of Cr (VI) from water.