Metals Chromium Research Articles

Quantification of toxic metals in chicken egg and chicken feed via SOM-artificial neural network.

Poultry products such as meat and eggs are rich sources of proteins, vitamins, and minerals. It is a good indicator of healthy food. Keeping in view, the present study is designed to evaluate the prevalence of toxic heavy metals (lead, nickel, cadmium, and chromium) in chicken eggs and feed. For this purpose, five samples of egg and feed were collected from five different commercial markets in Skardu City. Each sample was prepared using the wet digestion method and analyzed using a flame atomic absorption spectrophotometer. The results showed that lead, nickel, and chromium were present in varying amounts in the feed and egg, with nickel being the most concentrated metal, followed by lead and chromium in egg samples, while the feed samples showed the highest concentration of chromium followed by lead and nickel. However, concentrations of selected heavy metals except cadmium were all above the permissible limit of the World Health Organization. The self-organizing map-artificial neural network is employed for the identification of patterns of heavy metals in chicken feed and egg samples. The lower left neurons of the maps showed higher heavy metal concentrations found in samples taken from Bazar, whereas the rest of the samples showed varied concentrations. A comparison of feed and egg concentrations showed that nickel concentration was lower in feed samples than in egg samples. The lead concentration decreased in eggs except in the Krasmathang feed sample. Chromium concentration presented a negative correlation due to the extremely high concentration found in the Bazar feed sample.

Toxic textiles: Potential health risks associated with toxic chemicals in clothing

Toxic textiles: Potential health risks associated with toxic chemicals in clothing Maria A. Muñoz and Pamela J. Lein from the University of California, Davis, focus on the potential health risks associated with toxic chemicals in clothing. In 2011, approximately 800 of 3,000 Alaska Airlines attendants began reporting various symptoms, including skin rashes, itchy eyes, and coughing. These complaints coincided with the introduction of new uniforms earlier that year and would continue until February 2014, when the clothing was recalled. Laboratory analyses of the attendants’ uniforms detected various toxic chemicals, including metals (lead, chromium, and cobalt) and known skin irritants, such as toluene, tributyl phosphate, and dimethyl fumarate, in the cloth used to make the uniforms.

QUANTITATIVE DETERMINATION OF SELECTED HEAVY METALS AND MICRONUTRIENTS IN BRANDED DAIRY PRODUCTS SOLD IN NIGERIA USING ATOMIC ABSORPTION SPECTROSCOPY (AAS)

Quantitative analysis of heavy metals and nutrients in food helps indicate the safety and quality of food for final consumers. The present study was conducted to assess the presence of heavy metals (arsenic, copper, mercury, chromium, and lead) and the nutritional value of calcium in branded milk and yogurt to evaluate health risks for consumers. Ten (10) samples of branded milk and dairy products manufactured in Nigeria were purchased. The metal contents of the samples were determined using atomic absorption spectroscopy. The concentrations of calcium in the milk samples were between 9.33 ± 0.0023 and 18 ± 0.0071 ppm and were detected in all samples. Arsenic concentrations ranged from 0.45 ± 0.00042 to 2.48 ± 0.00064 ppm in eight branded samples but were undetected in two samples. Chromium levels were undetected in most samples, except for two with concentrations of 0.12±0.00049 ppm and 0.23±0.00021 ppm, respectively. Copper ranged from 0.032±0.00021 ppm to 0.129±0.00021 ppm in six samples. Mercury levels were detected in six samples at a concentration of 1.0±1.0 ppm. Lead concentrations ranged from 0.15±0.00064 to 0.29±0.00028 ppm in three samples. The study found heavy metals above the ideal concentration in branded milk and dairy products in Nigeria, highlighting the need for quality control measures during production to prevent contamination.

Effect of chromium and cations concentration on stress enzymes in spinach crop grown under vertisol of central India

Interaction of chromium (Cr) metal ions with sodium (Na) and calcium (Ca) and their effect on the different plant enzymes in spinach were evaluated in a glass house experiment. Multi-metal toxicity hampers the crop's growth and affects the uptake kinetics of minerals and other substances from root to edible part. In this experiment, three levels of Cr (0, 50 and 100 mg/kg), Na levels (0, 40, 80 mM), and Ca levels (0, 2, 4 mM) were applied to Indian vertisol. The spinach crop was grown with recommended agronomic practices. Fully tender leaves were taken to measure stress enzymes (catalase, superoxide dismutase (SOD), peroxidase) of metals; and found to have a significant effect on metal toxicity in spinach crop. Increasing the Cr level up to 100 mg/kg significantly enhanced the activities of catalase, SOD, and peroxidase in spinach; whereas, a lower level of Ca and Na with 50 mg Cr/kg soil significantly (p < 0.05) didn't affect the stress enzymes level. However, increasing the salt ions concentration up to 4 mM of Ca and 80 mM of Na with 50 and 100 mg Cr/kg soil enhanced the catalase, peroxidase and SOD activities from 1.61 to 5.42 mg protein/min, 4.26–59.87 mg protein/min and 4.36–64.42 g/fresh weight, respectively. The SOD activity was measured to be more than the catalase and peroxidase under the interactive effect of salt ions and Cr. Such an experiment is useful to identify a metal's toxic effect on crops grown under poor-quality natural resources for executing efficient management strategies for better crop yield.

Quantitative analysis of the compliance of EU Sewage Sludge Directive by using the heavy metal concentrations from LUCAS topsoil database.

In the European Union (EU), a common understanding of the potential harmful effect of sewage sludge (SS) on the environment is regulated by the Sewage Sludge Directive 86/278/EEC (SSD). Limit values (LVs) for concentrations of heavy metals in soil are listed in Impact Assessment of this directive, and they were transposed by EU member states using different criteria. Member states adopted either single limit values or based on soil factors such as pH and texture to define the maximum limit values for concentrations of heavy metals in soils. Our work presents the first quantitative analysis of the SSD at the European level by using the Land Use and Coverage Area Frame Survey (LUCAS) 2009 topsoil database. The reference values at the European level were arranged taking into account the upper value (EU_UL) and the lower value (EU_LL) for each heavy metal (arsenic, cadmium, copper, chromium, mercury, nickel, lead, and zinc) as well as taking into account the pH of the soil (cadmium, copper, mercury, nickel, lead, and zinc) as introduced in the SSD Annex IA. Single and integrated contamination rate indices were developed to identify those agricultural soils that exceeded the reference values for each heavy metal. In total, 10%, 36%, and 19% of the LUCAS 2009 topsoil samples exceeded the limit values. Additionally, 12% and 16% of agricultural soils exceeded the concentration of at least one single heavy metal when European LVs were fixed following the soil pH in Strategy II compared to those national ones in Strategy I. Generally, all member states apply similar or stricter limit values than those laid down in the SSD. Our work indicates that choosing LVs quantitatively affects further actions such as monitoring and remediation of contaminated soils. The actual soil parameters, such as heavy metal concentrations and soil pH values from the LUCAS 2009 topsoil database, could be used by SSD-involved policy stakeholders not only to lay down the LVs for concentrations of heavy metal in soils but also for monitoring the SSD compliance grade by using the LUCAS surveys over time (past and upcoming LUCAS datasets).

Synergistic immobilisation of CeO2 as a surrogate for PuO2 and metallic FeCrAl alloy via zirconolite wasteform

Zirconolite wasteforms were designed for the co-immobilisation of CeO2 (as a PuO2 surrogate) and metallic iron, chromium, and aluminum, simulating contaminated FeCrAl alloy cladding. Zirconolite ceramics with the target composition Ca(1-3.87x)Ce3.87xZrTi(2-7.73x)Fe5.73xCrxAlxO7 (x = 0–0.11), were synthesised via solid state reaction sintering at 1400 °C. Phase and microstructural evolution were investigated to ensure the oxidation of the metals, formation of zirconolite phase and densification of the final ceramics. It was found that both oxidation and solid-state reaction could be accomplished by processing at 900 °C and 1400 °C under ambient atmosphere, accompanied by the overall yield of zirconolite in the range 92.4–94.0 wt % between x = 0.01–0.07 f.u., with a dense microstructure observed. Polytype transitions from zirconolite-2M to -3T were evidenced, where the solubility limit was reached at substitution level of x = 0.11 and precipitation of CeO2 was apparent. XPS analysis confirmed that an elevation in dopant concentration resulted in the partial reduction of Ce4+ to Ce3+, whereas Fe, Cr and Al metals were oxidised to the trivalent state. This study demonstrated the feasibility for designing advanced ceramic wasteforms for the co-immobilisation of actinides and metallic cladding residues.

Effect of Different Metal Bonding Agents on Shear Bond Strength of Ceramic to Direct Metal Laser Sintering

Introduction: laser sinter Cobalt Chromium metal replacing traditional casting processes of dental alloys for metal ceramic restorations, appropriate bonding of ceramic to metal is an important factor for long survival time. Twenty laser sinter cubic metal 10 mm for each sides was fabricated by software designing and CAD\CAM direct metal laser sintering technique. The twenty cubics were classified according to the type of metal to ceramic bonding agents into two groups (n=10), Ceram bond apply for group A and Crea alloy bond for group B. Samples fabricated using custom made silicon index was used to act as standardized mold for metal bond application and porcelain buildup. Instron with chisel indenter and special holding device were involve to measure the strength of bond for ceramic to laser sinter metal. The mean shear bond load of group A (688.8N) was significantly higher than that of group B (303.2N). Application of Ceram bond to metal laser sinter produces more bond strength when compare to usage of Crea bond material.

Large area nanoscale patterning of functional materials using organosilicate ink based nanotransfer printing

This paper presents a versatile nanotransfer printing method for achieving large-area sub-micron patterns of functional materials. Organosilicate ink formulations combined with effective release layers have been shown to facilitate patterning of materials through the commonly used patterning approaches—lift off, physical etching and chemical etching. In this paper, we demonstrate that organosilicate ink formulations function as an effective resist owing to its superior physico-chemical stability whereas the release layers ensure clean removal of the resist post patterning. We successfully demonstrate patterning of sub-micron structures (800 nm feature sizes) of chromium metal through the lift off approach, silicon through reactive ion etching technique and silicon dioxide through wet chemical etching technique illustrating the versatility of the reported method. This patterning methodology represents a significant advancement in enabling nanostructure fabrication within resource-constrained laboratories. The approach requires nothing more than a master mold containing the desired structures, a spin coater, a low-temperature hotplate, and a desktop reactive ion etch tool.

Oxidative response to accumulation of trace metals in tissue of two bivalves, the Asian green mussel Perna viridis and the blood cockle Tegillarca granosa, living in Pattani Bay, Thailand.

Using bivalves to indicate aquatic pollutants was favorable for discerning the negative effects of high levels of metal accumulation in tissue. We investigated the correlation between trace metal accumulation and the tissue oxidative response of two bivalves. The Asian green mussel Perna viridis and the blood cockle Tegillarca granosa were sampled along with seawater and sediments from three locations around Pattani Bay, Thailand. Accumulation of nine trace metals (cadmium, cobalt, copper, chromium, nickel, manganese, iron, zinc, and lead) in seawater, sediments, and tissue and the oxidative tissue response were evaluated. Metal bioaccumulation factor, biota-sediment accumulation factor, and histopathology were also indicated. The present study found that P. viridis and T. granosa were macroconcentrators and bioaccumulative of cadmium, and their tissue accumulation of cadmium was strongly related to lipid peroxidation activation. Perna viridis exhibited a higher oxidative response than T. granosa, as indicated by malondialdehyde, catalase, and reduced glutathione levels. The present study indicated that P. viridis and T. granosa were macroconcentrators and bioaccumulative of cadmium, and their tissue accumulation of cadmium was strongly related to lipid peroxidation activation. Research has shown discernible negative effects of a high level of metal accumulation in tissue, and deformed and damaged tissues were present in the gills, digestive glands, intestines, and feet of P. viridis and T. granosa.

Efficient removal and transformation of Cr(VI) from alkaline wastewater to form a ferrochromium spinel multiphase via a modified ferrite process

Chromium-containing wastewater causes serious environmental pollution due to the harmfulness of Cr(VI). The ferrite process is typically used to treat chromium-containing wastewater and recycle the valuable chromium metal. However, the current ferrite process is unable to fully transform Cr(VI) into chromium ferrite under mild reaction conditions. This paper proposes a novel ferrite process to treat chromium-containing wastewater and recover valuable chromium metal. The process combines FeSO4 reduction and hydrothermal treatment to remove Cr(VI) and form chromium ferrite composites. The Cr(VI) concentration in the wastewater was reduced from 1040 mg L−1 to 0.035 mg L−1, and the Cr(VI) leaching toxicity of the precipitate was 0.21 mg L−1 under optimal hydrothermal conditions. The precipitate consisted of micron-sized ferrochromium spinel multiphase with polyhedral structure. The mechanism of Cr(VI) removal involved three steps: 1) partial oxidation of FeSO4 to Fe(III) hydroxide and oxy-hydroxide; 2) reduction of Cr(VI) by FeSO4 to Cr(III) and Fe(III) precipitates; 3) transformation and growth of the precipitates into chromium ferrite composites. This process meets the release standards of industrial wastewater and hazardous waste and can improve the efficiency of the ferrite process for toxic heavy metal removal.

Investigation of nanofiltration systems efficiency for removal of chromium and copper from groundwater resources

AbstractThere is a vital need and constraint for providing water of good quality all around the world. Thus, with the aim of groundwater treatment, different methods of water treatment have been reviewed. Considering modern methods of membrane filtration, in this study efficiency of nanofiltration for removing heavy metals (copper and chromium) has been examined. The investigation has been accomplished in two separate phases for removing copper and chromium. To prepare the samples of groundwater, urban waters have been utilized and for preparation of chromium‐contaminated and copper‐contaminated waters, powder of chromium‐oxide and powder of copper sulfate pentahydrate have been added into samples, respectively. In this research, system‐operating pressure has been changed, while concentration and pH were kept constant. The effect of pressure on the efficiency of heavy metals removal has been checked and optimum pressure of the process has been achieved. Then, with optimal pressure as system operating pressure, the removal of heavy metals in different pH have been checked and accordingly, the optimal pH for the process was obtained. The Optimum Pressure and pH for chromium and copper are 7.5 bars and 6.3, and 7.5 bars and 6.7, respectively. Taking into account the result of this study, Nano filtration is a suitable method with high efficiency (90% and higher in optimum pressure and pH) for the removal of heavy metals from groundwater.

In situ Fe isotope analysis of Cr-rich iron oxides using pure chromium metal for isobaric interference corrections by femtosecond LA–MC–ICP–MS

Iron oxide minerals, such as hematite and magnetite, are commonly found in a wide range of geological environments. Their Fe isotopic composition acts as a potent geochemical tracer, finding applications across various realms of Earth sciences. However, natural iron oxide minerals often have a high Cr content up to percentile levels, necessitating correction of isobaric interference caused by 54Cr+ on 54Fe+ to ensure accurate and precise in situ Fe isotopic compositions. In this study, a pure chromium metal with homogeneous isotopic compositions was examined within the analysis sequence to obtain the fractionation factor of Cr (βCr) for isobaric interference correction. A femtosecond laser ablation system combined with wet plasma conditions was used to decrease the matrix effect. We synthesized a series of magnetite and hematite samples with simple matrix as well as natural magnetite samples with complex matrix to evaluate the feasibility of Cr interference correction. By employing our proposed correction method, the deviation caused by the isobaric interference of 54Cr+ was effectively eliminated. The corrected δ56Fe values for hematite and magnetite samples, even with a Cr/Fe ratio of as high as 1.27, exhibited good agreement with the reference values within the long-term reproducibility uncertainty of 0.10‰. These results indicate the robustness of Cr interference correction in obtaining accurate Fe isotopic compositions of Cr-rich iron oxides.

Neuro-environmental interactions: a time sensitive matter.

The assessment of resting state (rs) neurophysiological dynamics relies on the control of sensory, perceptual, and behavioral environments to minimize variability and rule-out confounding sources of activation during testing conditions. Here, we investigated how temporally-distal environmental inputs, specifically metal exposures experienced up to several months prior to scanning, affect functional dynamics measured using rs functional magnetic resonance imaging (rs-fMRI). We implemented an interpretable XGBoost-shapley additive explanation (SHAP) model that integrated information from multiple exposure biomarkers to predict rs dynamics in typically developing adolescents. In 124 participants (53% females, ages, 13-25 years) enrolled in the public health impact of metals exposure (PHIME) study, we measured concentrations of six metals (manganese, lead, chromium, copper, nickel, and zinc) in biological matrices (saliva, hair, fingernails, toenails, blood, and urine) and acquired rs-fMRI scans. Using graph theory metrics, we computed global efficiency (GE) in 111 brain areas (Harvard Oxford atlas). We used a predictive model based on ensemble gradient boosting to predict GE from metal biomarkers, adjusting for age and biological sex. Model performance was evaluated by comparing predicted versus measured GE. SHAP scores were used to evaluate feature importance. Measured versus predicted rs dynamics from our model utilizing chemical exposures as inputs were significantly correlated (p < 0.001, r = 0.36). Lead, chromium, and copper contributed most to the prediction of GE metrics. Our results indicate that a significant component of rs dynamics, comprising approximately 13% of observed variability in GE, is driven by recent metal exposures. These findings emphasize the need to estimate and control for the influence of past and current chemical exposures in the assessment and analysis of rs functional connectivity.

Electrochemical Sensors Go Nano: Carbon Nanomaterials for Ultrasensitive Heavy Metal Analysis

Background: Heavy metal contamination of food and the environment is a major concern worldwide. Conventional detection techniques like atomic absorption spectroscopy (AAS), inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS) have limitations including high costs and insufficient sensitivity. Electrochemical sensors based on carbon nanomaterials have emerged as an attractive alternative for rapid, affordable, and ultrasensitive heavy metal analysis. Methods: This review summarizes recent advances in using carbon nanomaterials like ordered mesoporous carbon, carbon nanotubes, graphene and carbon dots for electrochemical sensing of toxic heavy metals. Synthesis methods, characterization techniques, functionalization strategies and detection mechanisms are discussed. Results: High surface area, electrical conductivity and electrocatalytic activity of carbon nanomaterials enable preconcentration of metal ions and signal amplification at electrode interfaces. This results in remarkably low detection limits down to parts per trillion levels. Functionalization with metal nanoparticles, molecularly imprinted polymers and other nanocomposites further improves sensor selectivity and sensitivity. These sensors have been applied for the quantitative detection of arsenic, mercury, lead, cadmium, chromium, and other toxic metals in lab samples Conclusion: Electrochemical sensors based on carbon nanotubes, graphene, mesoporous carbon, and carbon dots are rapidly emerging as an ultrasensitive, cost-effective alternative to conventional techniques for on-site screening of heavy metal contamination in food and environment. Further validation using real-world samples and integration into portable field testing kits can enable widespread deployment.

Retraction: Sequestration of chromium(vi) and nickel(ii) heavy metals from unhygienic water via sustainable and innovative magnetic nanotechnology.

[This retracts the article DOI: 10.1039/D3NA00923H.].

Green-synthesized porous g-C3N4@ZnHCC nanocomposite for the on–off fluorescence detection and elimination of toxic chromium(vi) metal ions

Chromium(vi) is a significant environmental pollutant because of its highly hazardous and cancer-causing properties.

Chromium and other heavy metal pollution in surface waters

Chromium and other heavy metal pollution in surface waters

Sequestration of chromium(vi) and nickel(ii) heavy metals from unhygienic water via sustainable and innovative magnetic nanotechnology.

In a stride towards sustainable solutions, this research endeavors to address the critical issue of water pollution via heavy metals by coupling the power of magnetic nanotechnology, in combination with a green chemistry approach, to eliminate two noxious inorganic pollutants: chromium(vi) and nickel(ii) from aqueous environments. The synthesis of magnetite (Fe3O4) nanoparticles was achieved using ferric chloride hexahydrate (FeCl3·6H2O) as a precursor, with the assistance of Ziziphus mauritiana Lam. leaves extract, known for its remarkable salt-reducing properties. A range of bio-adsorbents, derived from corncob biomass, corncob pyrolyzed biochar, and magnetite/corncob biochar nanocomposite (NC), were engineered for their eco-friendly and biocompatible characteristics. Extensive parametric optimizations, including variations in pH, contact time, dose rate, and concentration, were carried out to gain insights into the adsorption behavior and capacity of these bioadsorbents concerning Cr(vi) and Ni(ii). Equilibrium and kinetic studies were undertaken to comprehensively understand the adsorption dynamics. In the case of Ni(ii), the Freundlich isotherm model provided a satisfactory fit for all bio-adsorbents, demonstrating R2 values of 0.91, 0.95, and 0.96 for BM, BC, and NC, respectively. Furthermore, the pseudo 1st order model emerged as the most suitable fit for Cr(vi) sequestration in corncob BM with an R2 value of 0.98, while pseudo 2nd order models were robustly fitted for BC and NC, yielding R2 values of 0.88 and 0.99, respectively. The magnetite/corncob nanocomposite outperformed other bioadsorbents in removing heavy metals from wastewater due to its environmental friendliness, larger surface area, reusability, and cost-effectiveness at an industrial scale.

Remediação eletrocinética de elementos potencialmente tóxicos de sedimentos da lagoa de Camorim

ABSTRACT Electrokinetic remediation, effective for low-permeability sediments, can remove both organic and inorganic contaminants simultaneously. This study investigated its application to dredged sediments from Camorim Lagoon (Jacarepaguá lagoon complex, Rio de Janeiro), known to be contaminated with potentially toxic metals (chromium, copper, lead, zinc, and nickel). A buffer solution controlled pH changes, while the complexing agent ethylenediaminetetraacetic acid (EDTA) and humic substances aided metal desorption and removal. Treatments utilizing EDTA (EK2 and EK3) achieved lower final concentrations of zinc and lead. Notably, EK1 (freshwater only) achieved the lowest nickel concentration observed in the anodic section. EK1 also achieved the lowest copper concentration; however, none of the treatments reached regulatory limits for copper. Chromium, which is the least mobile metal, is concentrated in the middle section for all treatments, suggesting the need for further electrolyte optimization to promote efficient chromium transport.

Current status of stream water quality around selected Tea Gardens from Southern Western Ghats, Tamil Nadu, India – A case study

In this study, metal concentration in tea garden-associated stream water samples from the south Western Ghats of Tamil Nadu was evaluated using ICP-MS to know the current status of pollution level, sources of pollution, probable water quality, and impacts of heavy metals. Stream water pollution of hill regions communities using the heavy metal pollution index, principal compound analysis, and Pearson correlation analysis were measured. In addition, for this purpose, water phy-chem parameters were also measured, such as (pH, temperature, conductivity, salinity, and TDS) using a pH meter. PO4 and F- UV-spectrophotometer, Na, K, and calcium (flame photo meter), NO3- NO3-N (Electronic method-horiba), and turbidity meter to evaluate the stream-water quality were used, and heavy metals, particularly Al, As, Cd, Fe, Cr, Cu, Zn, Pb, Ni, and Mn are analyzed as heavy metal pollutions. The phy-chem average values of pH, Temp, EC, Tds, Salinity, alkalinity, cod, bod, do, chloride, calcium, C. hardness, M. hardness, T. hardness, N-Nitrogen, Phosphate, Potassium, Sodium, Turbidity, Fluoride, Sulphate, and Sulphur are found 8.13, 27.57 °C, 218, 111.67, 78.67, 70.39, 2029, 5.70, 3.83, 70.83, 737, 62.30, 166.11, 679, 1132, 149, 11, 28.33, 4.44, 07, 178, 180 respectively. Heavy metal concentrations, including aluminum, arsenic, cadmium, iron, chromium, copper, zinc, lead, nickel, and manganese, are detected at 32, 7.2, 6.24, 96.4, 0.00, 0.00, 40, 0.00, 0.00, 30 μg/L, respectively. Concentrations of studied heavy metals, particularly, Mn, Ni, Cd, and Fe, have measurements that are greater than the permissible standard limits of BIS, WHO.