Simple and sensitive determination of Cr (III), Cu (II) and Pb (II) in tea infusions using AgNPs-modified resin combined with laser-induced breakdown spectroscopy.

The detection of heavy metals in tea infusions is important because of the potential health risks associated with their consumption. Existing highly sensitive detection methods pose challenges because they are complicated and time-consuming. In this study, we developed an innovative and simple method using Ag nanoparticles-modified resin (AgNPs-MR) for pre-enrichment prior to laser-induced breakdown spectroscopy for the simultaneous analysis of Cr (III), Cu (II), and Pb (II) in tea infusions. Signal enhancement using AgNPs-MR resulted in amplification with limits of detection of 0.22 µg L-1 for Cr (III), 0.33 µg L-1 for Cu (II), and 1.25 µg L-1 for Pb (II). Quantitative analyses of these ions in infusions of black tea from various brands yielded recoveries ranging from 83.3% to 114.5%. This method is effective as a direct and highly sensitive technique for precisely quantifying trace concentrations of heavy metals in tea infusions.

A promising approach for the removal of hexavalent and trivalent chromium from aqueous solution using low-cost biomaterial.

Heavy metal pollution is an enduring environmental challenge that calls for sustainable and eco-friendly solutions. One promising approach is to harness discarded plant biomass as a highly efficient environmental friendly adsorbents. In this context, a noteworthy study has spotlighted the employment of Euryale ferox Salisbury seed coat (E.feroxSC) for the exclusion of trivalent and hexavalent chromium ions. This study aims to transform discarded plant residue into a novel, environmentally friendly, and cost-effective alternative adsorbent, offering a compelling alternative to more expensive adsorption methods. By repurposing natural materials, we can contribute to mitigating heavy-metal pollution while promoting sustainable and economically viable solutions in environmental remediation. The effect of different parameters, i.e., chromium ions' initial concentration (5-25 mg L-1), solution pH (2-7), adsorbent dosage (0.2-2.4 g L-1), contact time (20-240 min), and temperature (298-313 K), were investigated. E.feroxSC proved highly effective, achieving 96.5% removal of Cr(III) ions at pH 6 and 97.7% removal of Cr(VI) ions at pH 2, with a maximum biosorption capacity of 18.33 mg/g for Cr(III) and 13.64 mg/g for Cr(VI), making it a promising, eco-friendly adsorbent for tackling heavy-metal pollution. The adsorption process followed the pseudo-second-order kinetic model, aligning well with the Langmuir isotherm, exhibited favorable thermodynamics, and was characterized as feasible, spontaneous, and endothermic with physisorption mechanisms. The investigation revealed that E.feroxSC effectively adsorbed Cr(VI) which could be rejuvenated in a basic solution with minimal depletion in its adsorption capacity. Conversely, E.feroxSC's adsorption of Cr(III) demanded rejuvenation in an acidic milieu, exhibiting comparatively less efficient restoration.

Evaluation Health Risks and Sorption of Hexavalent Chromium (Cr(VI) by Biochar and Iron Doped Zinc Oxide Modified Biochar (Fe-ZnO@BC) Using Trifolium: A Green Synthesis Technique.

Contamination of aquatic and terrestrial environment with hexavalent chromium Cr(VI) is one of the major hazards worldwide due its carcinogenicity, persistency and immobility. Different research techniques have been adopted for Cr(VI) remediation present in terrestrial and aquatic media, while adsorption being the most advance, low cost, environmentally friendly and common method. The present study discussed the mechanisms of Parthenium hysterophorus derived biochar, iron-doped zinc oxide nanoparticles (nFe-ZnO) and Fe-ZnO modified biochar (Fe-ZnO@BC) involved in Cr(VI) mobility and bioavailability. Pot experiments were conducted to study the effect of Parthenium hysterophorus derived biochar, nFe-ZnO and Fe-ZnO@BC application rates (2%, 2 mg/kg, 10 mg/kg, respectively). The results indicated that the addition of soil amendments reduced Cr(VI) mobility. The findings revealed that the reduction in chromium mobility was observed by P. hysterophorus BC, and Fe-ZnO@BC but nFe-ZnO application significantly (p = 0.05) reduced Cr(VI) and CrT uptake as compared to the control treatments. The results of SEM coupled with EDS showed a high micropores and channel, smooth surface which helped in adsorption, and may enhance soil conditions. The concentration index (CI) by different amendments in trifolium plant was followed the descending order as: nFe-ZnO > Fe-ZnO@BC > P. hysterophorus BC after 30, 60 and 90 days of harvesting, respectively. In addition, human health risk index was found less than one (H1 < 1.0) in amended soils as compared to control treatments.

Heavy metal association with chronic kidney disease of unknown cause in central India-results from a case-control study.

BACKGROUND: Chronic Kidney Disease of unknown cause (CKDu) a disease of exclusion, and remains unexplained in various parts of the world, including India. Previous studies have reported mixed findings about the role of heavy metals or agrochemicals in CKDu. These studies compared CKDu with healthy controls but lacked subjects with CKD as controls. The purpose of this study was to test the hypothesis whether heavy metals, i.e. Arsenic (As), Cadmium (Cd), Lead (Pb), and Chromium (Cr) are associated with CKDu, in central India. METHODS: The study was conducted in a case-control manner at a tertiary care hospital. CKDu cases (n = 60) were compared with CKD (n = 62) and healthy subjects (n = 54). Blood and urine levels of As, Cd, Pb, and Cr were measured by Inductively Coupled Plasma- Optical Emission Spectrometry. Pesticide use, painkillers, smoking, and alcohol addiction were also evaluated. The median blood and urine metal levels were compared among the groups by the Kruskal-Wallis rank sum test. RESULTS: CKDu had significantly higher pesticide and surface water usage as a source of drinking water. Blood As levels (median, IQR) were significantly higher in CKDu 91.97 (1.3-132.7) µg/L compared to CKD 4.5 (0.0-58.8) µg/L and healthy subjects 39.01 (4.8-67.4) µg/L (p < 0.001) On multinominal regression age and sex adjusted blood As was independently associated with CKDu[ OR 1.013 (95%CI 1.003-1.024) P < .05].Blood and urinary Cd, Pb, and Cr were higher in CKD compared to CKDu (p > .05). Urinary Cd, Pb and Cr were undetectable in healthy subjects and were significantly higher in CKDu and CKD compared to healthy subjects (P = < 0.001). There was a significant correlation of Cd, Pb and Cr in blood and urine with each other in CKDu and CKD subjects as compared to healthy subjects. Surface water use also associated with CKDu [OR 3.178 (95%CI 1.029-9.818) p < .05). CONCLUSION: The study showed an independent association of age and sex adjusted blood As with CKDu in this Indian cohort. Subjects with renal dysfunction (CKDu and CKD) were found to have significantly higher metal burden of Pb, Cd, As, and Cr as compared to healthy controls. CKDu subjects had significantly higher pesticide and surface water usage, which may be the source of differential As exposure in these subjects.

Growth-dependent cr(VI) reduction by Alteromonas sp. ORB2 under haloalkaline conditions: toxicity, removal mechanism and effect of heavy metals.

Bacterial reduction of hexavalent chromium (VI) to chromium (III) is a sustainable bioremediation approach. However, the Cr(VI) containing wastewaters are often characterized with complex conditions such as high salt, alkaline pH and heavy metals which severely impact the growth and Cr(VI) reduction potential of microorganisms. This study investigated Cr(VI) reduction under complex haloalkaline conditions by an Alteromonas sp. ORB2 isolated from aerobic granular sludge cultivated from the seawater-microbiome. Optimum growth of Alteromonas sp. ORB2 was observed under haloalkaline conditions at 3.5-9.5% NaCl and pH 7-11. The bacterial growth in normal culture conditions (3.5% NaCl; pH 7.6) was not inhibited by 100 mg/l Cr(VI)/ As(V)/ Pb(II), 50 mg/l Cu(II) or 5 mg/l Cd(II). Near complete reduction of 100 mg/l Cr(VI) was achieved within 24 h at 3.5-7.5% NaCl and pH 8-11. Cr(VI) reduction by Alteromonas sp. ORB2 was not inhibited by 100 mg/L As(V), 100 mg/L Pb(II), 50 mg/L Cu(II) or 5 mg/L Cd(II). The bacterial cells grew in the medium with 100 mg/l Cr(VI) contained lower esterase activity and higher reactive oxygen species levels indicating toxicity and oxidative stress. In-spite of toxicity, the cells grew and reduced 100 mg/l Cr(VI) completely within 24 h. Cr(VI) removal from the medium was driven by bacterial reduction to Cr(III) which remained in the complex medium. Cr(VI) reduction was strongly linked to aerobic growth of Alteromonas sp. The Cr(VI) reductase activity of cytosolic protein fraction was pronounced by supplementing with NADPH in vitro assays. This study demonstrated a growth-dependent aerobic Cr(VI) reduction by Alteromonas sp. ORB2 under complex haloalkaline conditions akin to wastewaters.

Impact of organic matter molecular weight on hexavalent chromium enrichment in green microalgae.

In lightly polluted water containing heavy metals, organic matter, and green microalgae, the molecular weight of organic matter may influence both the growth of green microalgae and the concentration of heavy metals. This study elucidates the effects and mechanisms by which different molecular weight fractions of fulvic acid (FA), a model dissolved organic matter component, facilitate the bioaccumulation of hexavalent chromium (Cr(VI)) in a typical green alga, Chlorella vulgaris. Findings show that the addition of FA fractions with molecular weights greater than 10 kDa significantly enhances the enrichment of total chromium and Cr(VI) in algal cells, reaching 21.58%-31.09 % and 16.17 %-22.63 %, respectively. Conversely, the efficiency of chromium enrichment in algal cells was found to decrease with decreasing molecular weight of FA. FA molecular weight within the range of 0.22 µm-30 kDa facilitated chromium enrichment primarily through the algal organic matter (AOM) pathway, with minor contributions from the algal cell proliferation and extracellular polymeric substances (EPS) pathways. However, with decreasing FA molecular weight, the AOM and EPS pathways become less prominent, whereas the algal cell proliferation pathway becomes dominant. These findings provide new insights into the mechanism of chromium enrichment in green algae enhanced by medium molecular weight FA.

Equilibrium and kinetic modeling of Cr(VI) removal by novel tolerant bacteria species along with zero-valent iron nanoparticles.

This work describes the study of the removal of a refractory contaminant, i.e., Hexavalent chromium (Cr(VI)) from aqueous systems by a novel adsorbent comprising Cr(VI) tolerant bacteria and zero valent iron nanoparticle (nZVI). A gram-positive, rod-shaped bacteria used in the study were isolated from wastewater (WW) received from the effluent of leather industries. The adsorbents were prepared with bacteria, nZVI alone, and a combination of both. The adsorbent comprising both elements was found to remove Cr(VI) with a higher percentage (93%) and higher capacities (0.58 mg/g) as compared to adsorbent with bacteria (Cr(VI) removal = 63%, qe = 0.163 mg/g) or nanoparticles (Cr(VI) removal = 80%, qe = 0.45 mg/g) alone. The adsorbent worked best at neutral pH, and the removal became saturated after 90 min of incubation. Equilibrium studies with isotherm modeling suggested that the adsorption process follows sips isotherm (R2 = 0.9955), which is expected to bean intra-particle diffusion process before the actual adsorption. Process kinetics was modeled with pseudo-first order, pseudo-second order, and Vermeulen model. The diffusion coefficient determined by fitting the kinetic data to Vermeulen model was found to be 0.0000314 cm2/s. The adsorbent can be tested further for continuous flow processes to find more insights about the usage on a large scale.

Elevated cobalt levels in metal-on-polyethylene knee megaprostheses: a prospective 1-year cohort study of 56 patients with hip and knee megaprostheses.

BACKGROUND AND PURPOSE: Concerns have emerged regarding elevated levels of cobalt and chromium in patients with metal-on-metal megaprostheses. This prospective study aims to identify systemic cobalt and chromium levels in metal-on-polyethylene knee and hip megaprostheses and their associations with other factors. METHODS: 56 patients underwent knee or hip megaprosthesis surgery at 2 sarcoma centers. Serum cobalt and chromium levels were measured preoperatively and thrice within the first year using inductively coupled plasma mass spectrometry. RESULTS: A statistically significant difference in serum cobalt levels (1.4 ppb; 95% confidence interval [CI] 0.0-3.3) was observed 1 year after knee megaprosthesis surgery compared with preoperative levels. In contrast no difference in chromium levels was observed after 1 year compared with preoperative levels (0.05 ppb; CI 0.0-0.8). An association between younger age, higher eGFR, and increased cobalt levels was observed. No significant correlations were found between ion levels and resection length or the number of modular connections. CONCLUSION: We found elevated serum ion levels in metal-on-polyethylene knee megaprostheses in contrast to metal-on-polyethylene hip megaprostheses. Furthermore, a positive correlation between cobalt and chromium levels, and between cobalt and eGFR was identified, along with a negative correlation between cobalt and age. This study highlights the importance of monitoring systemic cobalt and chromium levels in patients with megaprostheses.

Leachability of hexavalent chromium from fly ash-marl mixtures in Sarigiol basin, Western Macedonia, Greece: environmental hazard and potential human health risk.

Hexavalent chromium (Cr (VI)) is an environmental contaminant brining high concerns due to its higher toxicity and mobility in comparison with trivalent chromium Cr(III). Cr (VI) has been linked with several adverse health effects, including respiratory diseases, lung cancer, and skin irritation. The primary sources of it in the environment are industrial activities.Most of the time, fly ash made of lignite can release Cr(VI) when it comes into contact with water in an aquatic environment. The objective of this study is the investigation of Cr (VI) concentration in leachates of fly ash and marl mixtures and the determination of its solubility under different pH conditions. Samples of fly ash were collected from the Power Plant of Agios Dimitrios. Additionally, samples of marl were collected from the mine of South Field, and both samples were mixed and prepared in in different proportions (% w.t.). The leaching experiments were carried out according to the EN-12457/1-4 (2003) standard under different pH conditions and chemical analysis of the leachates were performed by spectrophotometry with diphenylcarbazide (DPC). The environmental footprint of Cr (VI) in the study area was significant, especially in mixtures containing higher concentrations of fly ash. A critical pH range between 6 to 12 is observed. At acidic pH values, a high release of Cr (VI) was observed, while at the mentioned critical values (pH 10-12), a gradual decrease in its leachability was noticed. The high concentrations of Cr (VI) in the industrial area studied require immediate actions in terms of managing and limiting the potential hazardous impacts on the environment and by extension on the public health by developing appropriate prevention strategies.

Cr(VI) Reduction and Sequestration by FeS Nanoparticles Formed in situ as Aquifer Material Coating to Create a Regenerable Reactive Zone.

Remediation of large and dilute plumes of groundwater contaminated by oxidized pollutants such as chromate is a common and difficult challenge. Herein, we show that in situ formation of FeS nanoparticles (using dissolved Fe(II), S(-II), and natural organic matter as a nucleating template) results in uniform coating of aquifer material to create a regenerable reactive zone that mitigates Cr(VI) migration. Flow-through columns packed with quartz sand are amended first with an Fe2+ solution and then with a HS- solution to form a nano-FeS coating on the sand, which does not hinder permeability. This nano-FeS coating effectively reduces and immobilizes Cr(VI), forming Fe(III)-Cr(III) coprecipitates with negligible detachment from the sand grains. Preconditioning the sand with humic or fulvic acid (used as model natural organic matter (NOM)) further enhances Cr(VI) sequestration, as NOM provides additional binding sites of Fe2+ and mediates both nucleation and growth of FeS nanoparticles, as verified with spectroscopic and microscopic evidence. Reactivity can be easily replenished by repeating the procedures used to form the reactive coating. These findings demonstrate that such enhancement of attenuation capacity can be an effective option to mitigate Cr(VI) plume migration and exposure, particularly when tackling contaminant rebound post source remediation.

Relationships between blood chromium exposure and liver injury: Exploring the mediating role of systemic inflammation in a chromate-exposed population.

Hexavalent chromium and its compounds are prevalent pollutants, especially in the work environment, pose a significant risk for multisystem toxicity and cancers. While it is known that chromium accumulation in the liver can cause damage, the dose-response relationship between blood chromium (Cr) and liver injury, as well as the possible potential toxic mechanisms involved, remains poorly understood. To address this, we conducted a follow-up study of 590 visits from 305 participants to investigate the associations of blood Cr with biomarkers for liver injury, including serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), and direct bilirubin (DBIL), and to evaluate the mediating effects of systemic inflammation. Platelet (PLT) and the platelet-to-lymphocyte ratio (PLR) were utilized as biomarkers of systemic inflammation. In the linear mixed-effects analyses, each 1-unit increase in blood Cr level was associated with estimated effect percentage increases of 0.82% (0.11%, 1.53%) in TBIL, 1.67% (0.06%, 3.28%) in DBIL, 0.73% (0.04%, 1.43%) in ALT and 2.08% (0.29%, 3.87%) in AST, respectively. Furthermore, PLT mediated 10.04%, 11.35%, and 10.77% increases in TBIL, DBIL, and ALT levels induced by chromate, respectively. In addition, PLR mediated 8.26% and 15.58% of the association between blood Cr and TBIL or ALT. These findings shed light on the mechanisms underlying blood Cr-induced liver injury, which is partly due to worsening systemic inflammation.

Toxicological profile and potential health concerns through metals and trace elements exposure in brick kiln workers from Lahore, Pakistan.

This study examined levels of lead (Pb), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), and arsenic (As) in blood, hair, and nails of 18 brick kiln workers from three brick kiln units located around a metropolitan city, Lahore, Pakistan. All the trace elements except Hg and As were detected in the studied matrices of Brick kiln workers. In general, brick kiln workers reflect the highest concentration of Pb, followed by Cd, Cr, and Cu. Of the pollutants analyzed, Pb has the highest mean (min-max) concentrations at 0.35 (0.09-0.65) in blood (µg/mL), 0.34 (0.14-0.71) in hairs (µg/g), and 0.44 (0.32-0.59) in nails (µg/g) of brick kiln workers. Following Pb, the trend was Cd 0.17 (0.10-0.24), Cu 0.11(0.03-0.27), and Cr 0.07 (0.04-0.08) in blood (µg/mL), followed by Cr 0.11(0.05-0.20), Cd 0.09 (0.03-0.13), and Cu 0.08 (0.04-0.16) in hairs (µg/g) and Cu 0.16 (0.05-0.36), Cd 0.13 (0.11-0.17), and Cr 0.10 (0.05-0.14) in nails (µg/g) respectively. Relatively higher concentrations of metals and other trace elements in blood depicts recent dietary exposure. The difference of trace elements except Pb was non-significant (P > 0.05) among studied matrices of workers as well as between Zigzag and traditional exhaust-based brick kilns. The concentrations of Pb, Cd and Cr in blood of brick kilns workers are higher than the values reported to cause health problems in human populations. It is concluded that chronic exposure to metals and other trace elements may pose some serious health risks to brick kiln workers which needs to be addressed immediately to avoid future worst-case scenarios.

Tris buffer-accelerated ligand exchange rate for instant fluorescence detection of trivalent chromium ion.

Functional nucleic acids (FNAs) have attracted a lot of attention for the rapid detection of metal ions. Cr3+ is one of the major heavy metal ions in natural waters. Due to the slow ligand exchange rate of Cr3+, the FNA-based Cr3+ sensors require long assay times, limiting the on-site applications. In this study, we report that the good's buffers containing amino and polyhydroxy groups greatly increase the ligand exchange rate of Cr3+. Using EDTA as a model coordinate ligand, the Tris buffer (100 mM, pH 7.0) showed the best acceleration effect among the eight buffers. It improved the rate constant ∼20-fold, shorten the half-time 19-fold, and lowered the activation energy ∼70% at 40 °C. The Tris buffer was then applied for sensor based on the Cr3+-binding induced fluorescence quenching of fluorescein (FAM)-labeled and single-stranded DNA (ssDNA), which shortened the assay time from 1 h to 1 min. The Tris buffer also ∼100% enhanced the fluorescence intensity of FAM, achieving the 11.4-fold lower limit of detection (LOD = 6.97 nM, S/N = 3). By the combination use of the Tris buffer and ascorbic acid, the strong interference from Cu2+, Pb2+, and Fe3+ suffered in many previous reported Cr3+ sensors was avoided. The practical application of the sensor for the detection of Cr3+ spiked in the real water samples were demonstrated with high recovery percentages. The Tris buffer could be applied for other metal ions with slow ligand exchange rate (such as V2+, Co3+ and Fe2+) to solve diverse issues such as long assay time and low synthesis yield of metal complexes, without the need of heating treatment.

[Determination of 24 elements migration in Yixing clay pottery by inductively coupled plasma mass spectrometry].

OBJECTIVE: To establish an analytical method for determining the migration of 24 elements in Yixing clay pottery in 4% acetic acid simulated solution by inductively coupled plasma mass spectrometry. METHODS: Four types of Yixing clay pottery, including Yixing clay teapot, Yixing clay kettle, Yixing clay pot, and Yixing clay electric stew pot, were immersed in 4% acetic acid as a food simulant for testing. The migration amount of 24 elements in the migration solution was determined using inductively coupled plasma mass spectrometry. RESULTS: Lithium, magnesium, aluminum, iron, and barium elements with a mass concentration of 1000 µg/L; Lead, cadmium, total arsenic, chromium, nickel, copper, vanadium, manganese, antimony, tin, zinc, cobalt, molybdenum, silver, beryllium, thallium, titanium, and strontium elements within 100 µg/L there was a linear relationship within, the r value was between 0.998 739 and 0.999 989. Total mercury at 5.0 µg/L, there was a linear relationship within, the r value of 0.995 056. The detection limit of the elements measured by this method was between 0.5 and 45.0 µg/L, the recovery rate was 80.6%-108.9%, and the relative standard deviation was 1.0%-4.8%(n=6). A total of 32 samples of four types of Yixing clay pottery sold on the market, including teapots, boiling kettles, casseroles, and electric stewing pots, were tested. It was found that the migration of 16 elements, including beryllium, titanium, chromium, nickel, cobalt, zinc, silver, cadmium, antimony, total mercury, thallium, tin, copper, total arsenic, molybdenum, and lead, were lower than the quantitative limit. The element with the highest migration volume teapot was aluminum, magnesium, and barium; The kettle was aluminum and magnesium; Casserole was aluminum, magnesium, and lithium; The electric stew pot was aluminum. CONCLUSION: This method is easy to operate and has high accuracy, providing an effective and feasible detection method for the determination and evaluation of element migration in Yixing clay pottery.

The comprehensive strategy in the human health risk assessment of total chromium impurities in cough syrups with Marshmallow Root (Althaea officinalis) available in Polish pharmacies: regulatory aspects and special emphasis on Cr(VI) mode of action.

Chromium, which can currently only be considered pharmacologically active and not an essential element, is a very intriguing elemental impurity in final pharmaceutical products, especially traditional herbal medicinal products. This kind of traditional herbal medicinal product with Marshmallow root (Althaea officinalis L., radix) registered in the EU is widely used among the European population. The aim of this article is to propose a double regulatory strategy in assessing the human health risk of total chromium impurities in cough syrups with Marshmallow Root (Althaea officinalis) available in Polish pharmacies. We applied the strategy based on the requirements of the ICH Q3D (R1) guideline for the assessment of Cr impurities in final traditional herbal medicinal products with Marshmallow Root registered in the EU. Furthermore, we applied the strategy based on the concept of margin of exposure (MoE) considering Cr(VI) genotoxicity mode of action (MOA) and based on BMD10 for Cr(VI) as a point of departure (PoD). The total Cr content was in the range: 1.12-9.61 µg/L (in comparison with the ICH Q3D R1 guidelines: 1100 µg/g). Total Cr levels in a single dose were relatively high compared to raw results, but were not a threat to patients. Comparison of estimated results with oral PDE value for Cr in final drugs suggested by the ICH Q3D R1 guideline (10,700 µg/day) show that all the products analyzed were below this value (the highest result was 278.40 ng/day). Despite conservative assumptions, the MoE values obtained for Cr in daily dose for each Marshmallow Root cough syrup were above 10,000; therefore, exposure to Cr would not cause a health risk for specific population groups (children and adults). It can be summarized that each of the phytopharmaceuticals analysed with Marshmallow root available in Polish pharmacies does not represent a health hazard to patients. We confirm the safety of Cr impurities by applying a double regulatory strategy without the application of an expansive and demanding HPLC-ICP-MS technique for Cr speciation.

Mixture effects of trace element levels on cardiovascular diseases and type 2 diabetes risk in adults using G-computation analysis.

There is an increasing concern about the health effects of exposure to a mixture of pollutants. This study aimed to evaluate the associations between serum levels of heavy/essential metals ([Arsenic (As), Cadmium (Cd), Mercury (Hg), Lead (Pb), Nickel (Ni), Chromium (Cr), Copper (Cu), Iron (Fe), and Zinc (Zn)]) and the risk of developing cardiovascular diseases (CVDs) and type 2 diabetes mellitus (T2D). Data were collected from 450 participants (150 with CVDs, 150 with T2D, and 150 healthy subjects) randomly selected from the Ravansar Non-Communicable Disease (RaNCD) cohort in Western Iran, covering the years 2018-2023. Trace element levels in the serum samples were assayed using ICP-MS. Logistic regression was performed to estimate the adjusted risk of exposure to single and multi-metals and CVD/T2D. Odds ratios were adjusted for age, sex, education, residential areas, hypertension, and BMI. The mixture effect of exposure to multi-metals and CVD/T2D was obtained using Quantile G-computation (QGC). In the logistic regression model, chromium, nickel, and zinc levels were associated with CVD, and significant trends were observed for these chemical quartiles (P < 0.001). Arsenic, chromium, and copper levels were also associated with T2D. The weight quartile sum (WQS) index was significantly associated with both CVD (OR 4.17, 95% CI 2.16-7.69) and T2D (OR 11.96, 95% CI 5.65-18.26). Cd, Pb, and Ni were the most heavily weighed chemicals in these models.The Cd had the highest weight among the metals in the CVD model (weighted at 0.78), followed by Hg weighted at 0.197. For T2D, the serum Pb (weighted at 0.32), Ni (weighted at 0.19), Cr (weighted at 0.17), and Cd (weighted at 0.14) were the most weighted in the G-computation model. The results showed the significant role of toxic and essential elements in CVDs and T2D risk. This association may be driven primarily by cadmium and mercury for CVDs and Pb, Ni, Cr, and Cd for T2D, respectively. Prospective studies with higher sample sizes are necessary to confirm or refute our preliminary results as well as to determine other important elements.

Evaluation of urinary trace element levels in patients with opioid use disorder undergoing methadone treatment in western Iran.

The monitoring of essential and toxic elements in patients with Opioid Use Disorder (OUD) undergoing methadone treatment (MT) is important, and there is limited previous research on the urinary levels of these elements in MT patients. Therefore, the present study aimed to analyze certain elements in the context of methadone treatment compared to a healthy group. In this study, patients with opioid use disorder undergoing MT (n = 67) were compared with a healthy group of companions (n = 62) in terms of urinary concentrations of some essential elements (selenium (Se), zinc (Zn), copper (Cu), iron (Fe), manganese (Mn), calcium (Ca)) and toxic elements (lead (Pb), cadmium (Cd), arsenic (As), and chromium (Cr)). Urine samples were prepared using the acid digestion method with a mixture of nitric acid and perchloric acid and assessed using the ICP-MS method. Our results showed that the two groups had no significant differences in terms of gender, education level, occupation, and smoking status. Urinary concentrations of Se, Cu, and Fe levels were significantly lower in the MT group compared to the healthy subjects. However, the concentrations of Pb, Cd, As, Mn, Cr, and Ca in the MT group were higher than in the healthy group (p < 0.05). No significant difference was established between the levels of Zn in the two groups (p = 0.232). The results of regression analysis revealed that the differences between the concentration levels of all metals (except Zn) between two groups were still remained significant after adjusting for all variables (p < 0.05). The data obtained in the current study showed lower urinary concentrations of some essential elements and higher levels of some toxic elements in the MT group compared to the healthy subjects. These findings should be incorporated into harm-reduction interventions.

Metagenomic analysis revealed N-metabolizing microbial response of Iris tectorum to Cr stress after colonization by arbuscular mycorrhizal fungi.

Arbuscular mycorrhizal fungi (AMF) and plant growth-promoting bacteria enhance plant tolerance to abiotic stress and promote plant growth in contaminated soil. However, the interaction mechanism between rhizosphere microbial communities under chromium (Cr) stress remains unclear. This study conducted a greenhouse pot experiment and metagenomics analysis to reveal the comprehensive effects of the interaction between AMF (Rhizophagus intraradices) and nitrogen-N metabolizing plant growth promoters on the growth of Iris tectorum. The results showed that AMF significantly increased the biomass and nutrient levels of I. tectorum in contaminated soil and decreased the content of Cr in the soil. Metagenomics analysis revealed that the structure and composition of the rhizosphere microbial community involved in nitrogen metabolism changed significantly after inoculation with AMF under Cr stress. Functional genes related to soil nitrogen mineralization (gltB, gltD, gdhA, ureC, and glnA), nitrate reduction to ammonium (nirB, nrfA, and nasA), and soil nitrogen assimilation (NRT, nrtA, and nrtC) were up-regulated in the N-metabolizing microbial community. In contrast, the abundance of functional genes involved in denitrification (nirK and narI) was down-regulated. In addition, the inoculation of AMF regulates the synergies between the N-metabolic rhizosphere microbial communities and enhances the complexity and stability of the rhizosphere ecological network. This study provides a basis for improving plant tolerance to heavy metal stress by regulating the functional abundance of N-metabolizing plant growth-promoting bacteria through AMF inoculation. It helps to understand the potential mechanism of wetland plant remediation of Cr-contaminated soil.

Microbial innovations in chromium remediation: mechanistic insights and diverse applications.

The ubiquity of hexavalent chromium (Cr(VI)) from industrial activities poses a critical environmental threat due to its persistence, toxicity and mutagenic potential. Traditional physico-chemical methods for its removal often entail significant environmental drawbacks. Recent advancements in remediation strategies have emphasized nano and bioremediation techniques as promising avenues for cost-effective and efficient Cr(VI) mitigation. Bioremediation harnesses the capabilities of biological agents like microorganisms, and algae to mitigate heavy metal contamination, while nano-remediation employs nanoparticles for adsorption purposes. Various microorganisms, including E. coli, Byssochlamys sp., Pannonibacter phragmitetus, Bacillus, Aspergillus, Trichoderma, Fusarium, and Chlorella utilize bioreduction, biotransformation, biosorption and bioaccumulation mechanisms to convert Cr(VI) to Cr(III). Their adaptability to different environments and integration with nanomaterials enhance microbial activity, offering eco-friendly solutions. The study provides a brief overview of metabolic pathways involved in Cr(VI) bioreduction facilitated by diverse microbial species. Nitroreductase and chromate reductase enzymes play key roles in nitrogen and chromium removal, with nitroreductase requiring nitrate and NADPH/NADH, while the chromium reductase pathway relies solely on NADPH/NADH. This review investigates the various anthropogenic activities contributing to Cr(VI) emissions and evaluates the efficacy of conventional, nano-remediation, and bioremediation approaches in curbing Cr(VI) concentrations. Additionally, it scrutinizes the mechanisms underlying nano-remediation techniques for a deeper understanding of the remediation process. It identifies research gaps and offers insights into future directions aimed at enhancing the real-time applicability of bioremediation methods for mitigating with Cr(VI) pollution and pave the way for sustainable remediation solutions.