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Fishes are bio-concentrators for heavy metals, but cannot thrive in excessively polluted water. Heavy metals can accumulate in Arius arius, and cadmium (Cd) activates its metal-binding protein. Presently, Cd-binding metallothionein (MT) in A. arius is subjected to sub-lethal cadmium chloride (CdCl2 at 20 mg/L for 72 h). Separation of MT was achieved from liver homogenate supernatants via affinity chromatography and Sephadex G-25, assessed by 15% SDS-PAGE, verified by Western blotting, and quantified by MALDI-TOF. Using mass fingerprinting, peptide masses were searched in Swiss-Prot. A. arius bounded MT amino acid sequences matched Oreochromis mossambicus with 100%. The 60 amino acids of MT and cysteine content were identified (20 residues). MT contains 6021 daltons based on the MALDI-TOF–MS. The MT protein was modeled using modular9v8 software, confirmed using Ramachandran plot, and utilized as a biomarker for Cd toxicity in fish. The 3D structures might help to identify the binding sites and may lead to innovative treatments for stress and cadmium toxicity. [ABSTRACT FROM AUTHOR]

Cadmium is one of the most important environmental contaminants. Animals grazing on natural pastures are particularly exposed to cadmium. Sheep are mostly reared in extensive and grazing systems. Therefore, sheep may accumulate larger amounts of cadmium compared to other ruminant species and are a good indicator of exposure to cadmium contamination in a given area. The determination of cadmium concentrations in the muscles, livers and kidneys of lambs and sheep was carried out in the Czech Republic during the period 2001--2022. The average cadmium content in the livers and kidneys of all the lambs was 0.037 ± 0.006 and 0.061 ± 0.013 mg.kg-1, respectively. The average cadmium content in the livers and kidneys of all the sheep was 0.319 ± 0.047 and 1.255 ± 0.204 mg.kg-1, respectively. The maximum limit for human consumption was not exceeded in any of the 24 samples in the lambs but was exceeded in 5 of 33 liver samples and 12 of 33 kidney samples in the adult sheep. The average value of cadmium in the muscles of the lambs and sheep was 0.004 ± 0.001 mg.kg-1. The maximum limit for human consumption was not exceeded in any muscle sample. The cadmium content in both the liver and in the kidney differs significantly between the lambs and sheep, being higher in the sheep (P < 0.001 for both comparisons). No statistically significant trend of a decrease in the cadmium content in the lamb and sheep tissues was found during the observed time (P > 0.05). We can sum up that there is an evident need for further monitoring of the cadmium concentration in lamb and sheep tissues in the Czech Republic. [ABSTRACT FROM AUTHOR]

Quarries are regarded as crucial cornerstones of national economic development in Palestine. But they also have detrimental effects on the ecosystem and biological resources. Determination of the amount of heavy metals (chromium, cadmium, and lead) in quarries stumps is the main objective of the current research study. To accomplish this, 20 quarry stump samples were collected from four distinct regions of the Hebron Governorate in Palestine, using the quadrat method, and they were afterward calorimetrically assessed using a UV-visible spectrophotometer and pollution indices. The results reveal that the stumps possess Cr and Pb concentration below the international declared levels (1–1000 mg/l and 15–40 mg/l, respectively), while the Cd is above the declared level (0.2 mg/kg). The Cr and Pb content ranges from 0.128 to 0.611 mg/L and 0.125 to 0.779 mg/L, respectively. On contrary, the Cd contents varies from 0.362 to 8.572 mg/L in Hebron governorate. This level of Cd content, somehow, locate above their declared level by the international standards. In addition, the heavy metals content seems to be site-specific in the selected regions in Hebron governorate. The risk of cadmium is due to its high concentration, while the risk of Pb is because of its high toxicity. Moreover, the four regions are considered as uncontaminated and are clean based on PI Nemerow for Cr and Pb, but not for Cd. In conclusion, working on quarries in Hebron governorate is still safe from the levels of heavy metals point of view. However, more control and restriction must be implanted in order to mitigate its environmental and health consequences. Moreover, more research is needed to assess the occurrence of other heavy metals and their consequences on biological life and environmental issues. [ABSTRACT FROM AUTHOR]

Toxic metal wastewater is a challenge for exposed terrestrial and aquatic environments, as well as the recyclability of the water, prompting inputs for the development of promising treatment methods. Consequently, the rGO/ZnONP nanocomposite was synthesized at room temperature for four hours and was tested for the adsorption of cadmium and lead in wastewater. The optimized nanocomposite had the lowest band gap energy (2.69 eV), and functional group interactions were at 516, 1220, 1732, 3009, and 3460 cm−1. The nanocomposite showed good ZnO nanoparticle size distribution and separation on rGO surfaces. The nanocomposite's D and G band intensities were almost the same, constituting the ZnO presence on rGO from the Raman spectrum. The adsorption equilibrium time for cadmium and lead was reached within 10 and 90 min with efficiencies of ~100%. Sips and Freundlich best fitted the cadmium and lead adsorption data (R2 ~ 1); therefore, the adsorption was a multilayer coverage for lead and a mixture of heterogenous and homogenous coverage for cadmium adsorption. Both adsorptions were best fitted by the pseudo-first-order model, suggesting the multilayer coverage dominance. The adsorbent was reused for three and seven times for cadmium and lead. The nanocomposite showed selectivity towards lead (95%) and cadmium (100%) in the interfering wastewater matrix. Conclusively, the nanocomposite may be embedded within upcoming lab-scale treatment plants, which could lead to further upscaling and it serving as an industrial wastewater treatment material. [ABSTRACT FROM AUTHOR]

Purpose: Microplastics may affect the bioavailability of heavy metals in sediments primarily through direct adsorption. However, the potential of microplastics to alter the distribution of heavy metal chemical forms by interfering with the geochemical properties of sediments which may indirectly affect the bioavailability of heavy metals, has been overlooked. This study investigated the impact of two widely used biodegradable microplastics, polylactic acid (PLA) and polyhydroxyalkanoate (PHA), on the distribution of cadmium (Cd2+) in cadmium-contaminated sediments. Methods: Varying concentrations and particle sizes of PLA and PHA were added to Cd-pre-contaminated sediment and incubated under simulated submersion conditions for 60 days. The distribution of Cd2+ fraction in the sediment was determined, and the influence of biodegradable microplastics on cadmium mobility, through the regulation of sediment geochemical properties, was assessed. Results: Compared to the control group, the pH value and organic matter content of sediments treated with biodegradable microplastics significantly decreased, which in turn caused a transformation in the chemical form of cadmium. Higher concentrations and smaller particle sizes significantly promote a shift in cadmium components toward acid-soluble forms, thereby enhancing the mobility of cadmium in sediments, thereby amplifying its environmental toxicity. Conclusion: These results emphasize the potential of biodegradable microplastics to indirectly affect the mobility of cadmium by regulating sediment geochemical properties. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a dangerous heavy metal that is non-degradable in the environment. Many organs can accumulate Cd and adversely affect organ function and health. Cd is considered as a teratogenic and embryotoxic agent. This study aims to evaluate the teratogenicity of Cd at concentrations lesser than the permissible and its effects on the heart during chick embryogenesis. Fertilized eggs of the chick Gallus domesticus were divided into; control, saline injected and four experimental groups injected with single doses of 5, 25, 50 or 75 µM of CdCl2. Histological observations of the heart before hatching and the cardiomyocytes after hatching were recorded. Morphometric measurements of heart chambers were achieved at 3, 4 and 6 days of incubation. Electrocardiograph and respiratory rate were recorded at tenth day. Different cardiac problems had been brought on by Cd. In comparison to controls, the heart looked much larger, and in certain cases, growth retardation was seen. Degeneration in heart walls and malformations of dorsal aorta were noticed. Morphometrically, the width and wall thickness of heart chambers showed significant changes. Heart beats and respiratory rate significantly decreased compared to control. The cardiotoxic effect of Cd on heart compartments structure and function was dose dependent. One of Cd toxicity is its ability to induce cellular oxidative stress. The heart in particular is sensitive to oxidative stress. Cardiac oxidative stress might intensify heart failure and promote disease progression. Calcium is one of the components that is needed for normal heart work. Cd might interfere with calcium metabolism by removing it from the body. [ABSTRACT FROM AUTHOR]

Biochar remediation technology is increasingly being valued due to its economic and environmental advantages in treating heavy metal contaminated soil. In order to comprehensively grasp the research progress in this field, we analyzed the current research status, hotspots, and development directions of biochar passivation remediation of heavy metal contaminated soil based on the core collection database of Web of Science from 2008 to 2022, using bibliometrics and CiteSpace visualization technology. The analysis results indicate that since 2014, research on biochar remediation technology has become a hot topic in the treatment of heavy metal contaminated soil, and the number of literature in this field has grown rapidly. The application scope, mechanism of action, application effect, preparation method, and optimization technology of biochar are the main focus of this field. The selection of iron-modified biochar in the rice-soil system, biochar-based nanocomposites, and the combined application of phytoremediation and biochar are current research hotspots. The interaction mechanism between biochar and soil system, microbial remediation technology based on biochar, potential long-term effects of biochar use, and separation technology between biochar and soil are future research directions in the field of biochar remediation of heavy metal contaminated soil. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) contamination poses a significant threat to agriculture and human health due to its high soil mobility and toxicity. This review synthesizes current knowledge on Cd uptake, transport, detoxification, and transcriptional regulation in plants, emphasizing the roles of metal transport proteins and transcription factors (TFs). We explore transporter families like NRAMP, HMA, ZIP, ABC, and YSL in facilitating Cd movement within plant tissues, identifying potential targets for reducing Cd accumulation in crops. Additionally, regulatory TF families, including WRKY, MYB, bHLH, and ERF, are highlighted for their roles in modulating gene expression to counteract Cd toxicity. This review consolidates the existing literature on plant–Cd interactions, providing insights into established mechanisms and identifying gaps for future research. Understanding these mechanisms is crucial for developing strategies to enhance plant tolerance, ensure food safety, and promote sustainable agriculture amidst increasing heavy-metal pollution. [ABSTRACT FROM AUTHOR]

Purpose: This study focused on the selected markers of oxidative stress, impact of elevated lead levels on long-term hearing quality. We investigated whether the presence of certain essential minerals might provide protection to the auditory system against the effects of lead (and cadmium) compounds. Methods: The research group included 280 male employees of the zinc and lead smelter, which was divided into: L-Pb—low blood lead concentration (PbB) subgroup, H-Pb—high PbB subgroup. Hearing tests were performed using the click evoked otoacoustic emission (CEOAE). Results: Zinc protoporphyrin level was significantly higher in the H-Pb subgroup by 68%. Cd concentration was significantly higher in H-Pb by 33%. The Ca concentration was significantly lower in the H-Pb by − 2%. Selected oxidative stress markers concentration were significantly higher in the H-Pb group: malondialdehyde (MDA) by 4%, and lipofuscin (LPS) by 9%. In the CEOAE results showed statistically significant differences between the L-Pb and H-Pb subgroups. Larger negative changes in otoemission amplitude were observed in H-Pb subgroup. All otoemission results showed a statistically significant negative correlation with age, time of work, MDA concentration, and with PbB. Selected CEOAE parameters showed a significant negative correlation with cadmium blood concentration (CdB), and a positive correlation with Ca and Zn. Conclusion: Elevated blood lead content in occupational exposure is associated with an increase in MDA and LPS concentration, which negatively correlates with CEOAE parameters. This suggests an important role of oxidative stress in the long-term deterioration of hearing. [ABSTRACT FROM AUTHOR]

Chronic exposure to the nephrotoxic metal pollutant, cadmium (Cd), has been associated with hypertension, but the mechanism by which it raises blood pressure is not understood. We hypothesize that exposure to Cd reduces the glomerular filtration rate (GFR), which in turn causes a rise in blood pressure. Data were collected from 447 Thai subjects with a mean age of 51.1 years, of which 48.8% had hypertension, 15.4% had diabetes, and 6.9% had an estimated GFR (eGFR) below 60 mL/min/1.73 m2 (low eGFR). More than half (58.8%) and 23.9% had moderate and severe tubular proteinuria, respectively. The mean blood and urinary Cd concentrations were 2.75 and 4.23 µg/L, respectively. Doubling of body burden of Cd increased the prevalence odds ratios (POR) for low eGFR and severe tubular proteinuria 41% and 48%, respectively. The POR for hypertension rose twofold in those with blood Cd levels of 0.61–1.69 µg/L or urinary Cd excretion levels ≥ 0.98 µg/g creatinine. In the hypertensive group, the eGFR was inversely associated with age (β = −0.517), the Cd excretion rate (β = −0.177), and diabetes (β = −0.175). By mediation analysis, an increase in SBP was attributable totally to the effect of Cd on GFR. Thus, blood pressure appeared to rise as GFR fell. This finding is consistent with the well-known role of the kidney in long-term blood pressure regulation, and explains a universally high prevalence of hypertension among patients with low eGFR. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is one of the heavy metals that cause environmental pollution and biochemical changes in plants grown in contaminated soils. In plants, sodium nitroprusside is used as a nitric oxide (NO) release agent. In this research, a glasshouse pot experiment was conducted to examine the effect of exogenous NO on the essential oil composition of the savory plant, Satureja hortensis, under the Cd stress. For this, the plants were treated by different levels of Cd concentration including 0 (control), 75, 100, and 150 µM in the contaminated soil. Plants were also foliar sprayed with concentrations of 0 (control), 50, 100, and 200 µM NO. The results indicated that carvacrol was the main compound in all examined essential oils. Also, there were significant differences among the essential compounds under treatments of Cd and NO. Moreover, the differences among minor constituents were not significant in most of treatments. In apposite, carvacrol (approximately 60% of total volume) showed a significant difference than the others. The results indicated the role of exogenous agents on the changes of essential oil constituents in S. hortensis. [ABSTRACT FROM AUTHOR]

Acid rain and heavy metal cadmium (Cd) pollution are global environmental problems affecting plants. Plant priming with calcium (Ca) alleviates various environmental stresses. However, the mitigation effect of exogenous Ca on Bermuda grass has not been evaluated under the dual stress of Cd and acid rain. This research was designed to explore the effect of 5 mmol/L Ca on the growth of Bermuda grass seedlings under the combined stress. The results showed that exogenous Ca improved the growth indicators including root length, plant height, stem length, leaf length, root dry weight, stem dry weight, leaf dry weight and total dry weight, reduced the MDA content, and increased the relative chlorophyll content, SOD, POD and CAT activity, and N, P, K contents in different organs. The alleviating effect of exogenous Ca was be limited by acid rain intensity. Exogenous Ca had a significant alleviating effect on plants under combined stress of Cd and pH4.5 acid rain, and promoted the Cd uptake in plants. This research provided a scientific basis for further understanding the positive effects of exogenous Ca on plant growth under the combined stress of Cd and acid rain, and phytoremediation of soil Cd pollution in acid rain areas. [ABSTRACT FROM AUTHOR]

The global concern over health issues related to heavy metal pollution has driven the adoption of various treatment technologies. The investigation into optimal conditions for cadmium biosorption and bioaccumulation was conducted using a resilient bacterial strain, Pseudomonas aeruginosa DR7, which was isolated from ponds. The equilibrium time of the adsorption process of living cells was much longer than that of non‐living cells, which was about 240 min, which indicates that living cells have intracellular accumulation and delay the adsorption process. Living cells favored a pH of 6.0, while non‐living cells showed higher efficiency at pH 7.0, demonstrating the pH‐dependent nature of metal biosorption. In this context, the maximum biosorption capacities for cadmium using non‐living cells and living cells were 103.8 mg/g and 70.94 mg/g, under cell mass of 1.0 g/L, pH 7.0, initial metal concentration of 200 mg/L, and contact time of 240 min, respectively. Cadmium biosorption by living cells was more accurately described by the Freundlich isothermal model, whereas the Langmuir model was used for non‐living cells. Living cells tend to show pseudo‐second‐order kinetic adsorption behavior, while non‐living cells tend to show pseudo‐first‐order kinetic adsorption behavior. Fourier‐transform infrared spectroscopy (FTIR) analysis suggested that the hydroxyl, amino, and carboxyl groups all play a role in biosorption. Scanning electron microscopy (SEM)–energy dispersive x‐ray spectroscopy (EDS) showed that the high‐temperature treatment destroys the integrity of the cell wall, which enhances the permeability of the cell wall, thus increasing the biosorption of Cd (II) by the non‐living cells. The study found that P. aeruginosa DR7 with high temperature inactivation has a higher Cd(II) adsorption capacity than living cells, making it a green and environmentally friendly biological adsorbent for wastewater treatment with heavy metals. [ABSTRACT FROM AUTHOR]

Combined polymetallic exposure may be an influential factor in osteoporosis. This study aimed to explore the association between polymetallic combined exposure and osteoporosis. A total of 2115 participants were included. Plasma concentrations of 22 metals were determined by inductively coupled plasma mass spectrometry. Osteoporosis was defined as a T ≤ − 2.5. The least absolute shrinkage and selection operator (LASSO) regression, binary logistics regression, and Bayesian kernel machine regression (BKMR) model were used to explore the association between plasma metals and osteoporosis. LASSO regression showed that 10 metals were associated with osteoporosis in the total population (magnesium, calcium, manganese, nickel, cobalt, arsenic, selenium, rubidium, cadmium, aluminum) and women (magnesium, calcium, molybdenum, nickel, cobalt, arsenic, selenium, rubidium, cadmium, aluminum), and four metals associated with men (magnesium, cobalt, aluminum, iron). Logistics regression showed that in total population, magnesium (ORQ3 = 0.653, 95% CI = 0.446–0.954) was negatively correlated with osteoporosis, while aluminum (ORQ2 = 1.569, 95% CI = 1.095–2.248, ORQ4 = 1.616, 95% CI = 1.109–2.354) and cadmium (ORQ4 = 1.989, 95% CI = 1.379–2.870) were positively correlated; in women, magnesium (ORQ3 = 0.579, 95% CI = 0.379–0.883) was negatively correlated with osteoporosis, while aluminum (ORQ2 = 1.563, 95% CI = 1.051–2.326, ORQ4 = 1.543, 95% CI = 1.024–2.326) and cadmium (ORQ3 = 1.482, 95% CI = 1.003–2.191, ORQ4 = 1.740, 95% CI = 1.167–2.596) were positively correlated. BKMR model showed that combined polymetallic exposure had an overall positive effect on osteoporosis, magnesium was negatively associated with osteoporosis, and cadmium, selenium, and aluminum were positively associated with osteoporosis. Metal mixtures in plasma were associated with osteoporosis risk. Magnesium may reduce the risk of osteoporosis, while cadmium, selenium, and aluminum may increase the risk of osteoporosis. Future studies needed to explore correlations and mechanisms. [ABSTRACT FROM AUTHOR]

It is important to consider how phosphate-based metal immobilization differs from traditional soil incubation because of the presence of low molecular weight organic acids (LMWOAs) in the rhizosphere. Therefore, in an incubation study, the impacts of 3% NaH2PO4 (a P compound), tartaric acid (TA), oxalic acid (OA), and combinations of P and TA/OA on cadmium (Cd), lead (Pb), and zinc (Zn)'s geochemical redistribution and availability in metal-contaminated soils were studied. The mechanisms of metal immobilization were also explored. P, a low TA (TA2), and P plus a low TA (p-TA2) significantly reduced Cd, Pb, and Zn's acid-extractable and available (CaCl2-extractable) forms compared to the control (CK), with p-TA2 being the most effective. At high TA (>TA5–TA20), all OA levels (OA2–OA20), and P plus high TA/OA concentrations, trends reversed. Treatments became more negative as pH increased, particularly p-TA2, indicating that the main mechanism for immobilizing metals was electrostatic adsorption. However, XRD showed that the P material alone formed Cd-P, Pb-P, and Zn-P minerals, implying that sorption and precipitation were the primary metal immobilizing techniques. In conclusion, p-TA2 has the potential to effectively immobilize metals in contaminated soils. However, when treating metal-contaminated soils with P, rhizospheric LMWOAs must be considered. [ABSTRACT FROM AUTHOR]

Heavy metal ions such as cadmium, mercury, lead, and arsenic in the soil cannot be degraded naturally and are absorbed by crops, leading to accumulation in agricultural products, which poses a serious threat to human health. Therefore, establishing a rapid and efficient method for detecting heavy metal ions in agricultural products is of great significance to ensuring the health and safety. In this study, a novel optimized spectrometric method was developed for the rapid and specific colorimetric detection of cadmium ions based on N-(2-Acetamido)-iminodiacetic acid (ADA) and Victoria blue B (VBB) as the chromogenic unit. The safety evaluation of ADA showed extremely low biological toxicity in cultured cells and live animals. The standard curve is y = 0.0212x + 0.1723, R2 = 0.9978, and LOD = 0.08 μM (0.018 mg/kg). The liner concentrations detection range of cadmium is 0.1–10 μM. An inexpensive paper strip detection method was developed with a detection limit of 0.2 μM to the naked eye and a detection time of less than 1 min. The method was successfully used to assess the cadmium content of rice, soybean, milk, grape, peach, and cabbage, and the results correlated well with those determined by inductively coupled plasma–mass spectrometry (ICP-MS). Thus, our study demonstrated a novel rapid, safe, and economical method for onsite, real-time detection of cadmium ions in agricultural products. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) contamination in soil pore water is the primary pathway for Cd uptake by food crops, such as rice (Oryza sativa L.), posing significant risks to both food safety and human health. This study presents a novel soil pore water metal sensor (SPW-Msensor) for in situ and online monitoring of Cd in soil pore water (Cdpw). The SPW-Msensor integrates an automated sampling device, comprising a Rhizon sampler and a reciprocating series pump with an independent dual plunger drive, along with a portable electrochemical sensor consisting of a screen-printed electrode, flow cell, and portable potentiostat. The SPW-Msensor enables the detection of Cd within a linear range of 50 to 300 ppb while exhibiting high anti-interference capability. Moreover, it demonstrates excellent repeatability (relative standard deviation values (RSDs) <3.6%) across 30 measurements conducted within a 2-h period. The method exhibits good agreement with results obtained using the standard ICP-MS method (RSDs < 5%). Additionally, this study establishes a positive correlation between Cdpw detected by the SPW-Msensor and total Cd concentration (Cdtotal) in the soil with an R2 value equal to 0.89. Data acquired from the SPW-Msensor can be utilized for predicting Cdtotal through partial least squares regression modeling, achieving model quality score (Q2) of 0.69, adjusted R2 of 0.9345, and root mean square error (RMSE) of 0.1912. The SPW-Msensor demonstrates real-time monitoring capabilities for assessing Cd levels in acidified soils. This SPW-Msensor offers an efficient approach for in-situ and continuous monitoring of Cdpw that provides valuable insights applicable to environmental and agricultural domains. [ABSTRACT FROM AUTHOR]

Long interspersed nuclear element-1 (LINE-1) methylation serves as an indicator of global DNA methylation. This study explored the correlation between LINE-1 methylation and chronic kidney disease (CKD). We also evaluated whether LINE-1 methylation could modify the association between CKD and metal exposure. A total of 213 patients with clinically defined CKD, without hemodialysis and 416 age and sex matched controls were recruited. Levels of LINE-1 methylation, total urinary arsenic, blood lead, blood cadmium, and plasma selenium were assessed. The results reveal a positive association between LINE-1 methylation and CKD, with an odds ratio (OR) of 5.30 (95% confidence interval: 2.81 to 9.99). Total urinary arsenic and blood cadmium concentrations were positively related with LINE-1 methylation. This study was the first to observe that low plasma selenium, high blood cadmium, and high blood lead levels significantly and additively interact with increased LINE-1 methylation to increase the OR of CKD. Additionally, high LINE-1 methylation interacted multiplicatively with low plasma selenium to increase the OR of CKD (p < 0.001). This study highlighted the significant association between LINE-1 hypermethylation and CKD. Furthermore, the results demonstrate that LINE-1 methylation can interact with high blood cadmium or low plasma selenium to affect CKD risk. [ABSTRACT FROM AUTHOR]

Biochar and iron ore tailing waste have been widely separately applied for remediation of various contaminants, but the remediation effect of their combination on cadmium (Cd) pollution is unclear. In this study, the peanut biochar (BC), thermally activated iron ore tailing waste (TS), and the products of the co-pyrolysis of peanut shell and iron ore tailing waste (TSBC) were prepared for stabilizing Cd and reducing its bio-accessibility in soil and peanut seedling system. Present amendments enhanced soil pH, cation exchange capacity, electrical conductivity, and organic carbon content. The application of BC, TS, and TSBC led to decreases in acid-extractable Cd proportion of 2.2–8.81%, 2.43–7.20%, and 7.84–11.57%, respectively, and increases in the residual Cd proportion of 3.48–8.33%, 3.27–11.50%, and 9.02–13.45%, respectively. There were no significant differences in Cd accumulation in peanut roots due to three amendments treatments, especially at low Cd concentrations (i.e., Cd concentration of 0, 1, and 2 mg·kg−1), and with a relatively small reduction (2.16–9.05%) in root Cd accumulation under the high Cd treatments of 5 and 10 mg·kg−1. The Cd concentrations in seedling roots were significantly positively related to the acid-extractable Cd fraction, with a Pearson correlation coefficient of r = 0.999. The maximum toxicity mitigating effects were found in TSBC treatment, with increases in the ranges of 9.80–17.58% for fresh weight, 5.59–14.99% for dry weight, 5.16–10.17% for plant height, 5.96–10.34% for root length, 5.43–21.67% for chlorophyll a content, 17.17–71.28% for chlorophyll b content, and 13.11–39.60% for carotenoid content in peanut seedlings. Therefore, TSBC is a promising amendment for minimizing Cd contamination in peanut crops and utilizing industrial solid waste materials efficiently. [ABSTRACT FROM AUTHOR]

Rice (Oryzasativa) is an important nutritional grain for the majority of Asian countries, but it is also a major source of cadmium (Cd) accumulation. A pot experiment was carried out to investigate the Cd uptake and translocation of high Cd (IR-50) and low Cd (White Ponni) rice cultivars in Cd-contaminated soils. The findings revealed that Cd impacts on rice development and growth differed depending on rice cultivars. Soil Cd levels in the seedling stage exceeded the critical levels (3–6 mg kg−1) only 5.0 mg kg−1 Cd treatment for the IR-50 (7.47 mg kg−1). At higher Cd treatments (1.0 and 5.0 mg kg−1), morphometric characteristics and yield of grains showed a declining and increasing trend in both rice varieties, respectively. The accumulation of Cd was higher in soil and roots during seedling and tillering stages, whereas in booting and maturity stages increased in stems and leaves in IR-50 and WP rice varieties. Cd levels in rice grains above the maximum allowable limit (0.4 mg kg−1) only in IR-50 (0.51 mg kg−1) rice cultivar at maturity stage. The EF of Cd were classified as minor enrichment to ‘moderate enrichment’ in both rice cultivars. TF values exhibited > 1 in booting and maturity stages in both rice cultivars at higher Cd treatments. The study concluded that the IR-50 rice variety exhibited increased Cd intake and transported to various parts of rice plants, particularly grains. The findings indicate that WP rice cultivar is more resistant to Cd toxicity, reducing health hazards for persons who preferred the staple food rice. [ABSTRACT FROM AUTHOR]

Mining activities have resulted in a substantial accumulation of cadmium (Cd) in agricultural soils, particularly in southern China. Long-term Cd exposure can cause plant growth inhibition and various diseases. Rapid identification of the extent of soil Cd pollution and its driving factors are essential for soil management and risk assessment. However, traditional geostatistical methods are difficult to simulate the complex nonlinear relationships between soil Cd and potential features. In this study, sequential extraction and hotspot analyses indicated that Cd accumulation increased significantly near mining sites and exhibited high mobility. The concentration of Cd was estimated using three machine learning models based on 3169 topsoil samples, seven quantitative variables (soil pH, Fe, Ca, Mn, TOC, Al/Si and ba value) and three quantitative variables (soil parent rock, terrain and soil type). The random forest model achieved marginally better performance than the other models, with an R2 of 0.78. Importance analysis revealed that soil pH and Ca and Mn contents were the most significant factors affecting Cd accumulation and migration. Conversely, due to the essence of controlling Cd migration being soil property, soil type, terrain, and soil parent materials had little impact on the spatial distribution of soil Cd under the influence of mining activities. Our results provide a better understanding of the geochemical behavior of soil Cd in mining areas, which could be helpful for environmental management departments in controlling the diffusion of Cd pollution and capturing key targets for soil remediation. [ABSTRACT FROM AUTHOR]

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OsNRAMP5 is a pivotal gene involved in the uptake and transport of cadmium and manganese in rice plants. While the knockout of OsNRAMP5 has significantly decreased cadmium accumulation in rice grains, its impact on the adaptability of indica hybrid rice and its paternal parent still needs to be more adequately explored. This study conducted a three-year field experiment with two of the OsNRAMP5 knockout lines (indica hybrid rice LYDG-1 and its paternal parent DG-1) and their wild-type at four distinct locations in the middle reaches of the Yangtze River. Their adaptability was evaluated by cadmium and manganese accumulation, yield traits, and grain quality. The findings reveal that OsNRAMP5 knockout lines, when grown in mildly and moderately Cd-contaminated paddies, exhibit significantly and stably lower cadmium and manganese accumulation compared with the wild-type. However, there were no significant differences in cadmium and manganese content between LYDG-1 and DG-1. Regarding yield traits, OsNRAMP5 knockout lines did not show a significant reduction compared with the wild-type, except for DG-1 in soil with lower manganese content. For grain quality, the quality of the appearance of OsNRAMP5 knockout lines significantly improved compared with the wild-type. However, the milling quality of DG-1 significantly reduced compared with the wild-type, while this negative impact for LYDG-1 was only observed in soils with lower manganese content. Overall, the indica hybrid rice with an OsNRAMP5 knockout exhibits better adaptability than its paternal parent in the middle reaches of the Yangtze River. These findings offer valuable insights into the potential application and promotion of OsNRAMP5 mutant rice varieties in the middle reaches of the Yangtze River. [ABSTRACT FROM AUTHOR]

Our research addresses the pressing need for environmental sensors capable of large-scale, on-site detection of a wide array of heavy metals with highly accurate sensor metrics. We present a novel approach using electrochemically polished (ECP) carbon screen-printed electrodes (cSPEs) for high-sensitivity detection of cadmium and lead. By applying a range of techniques, including scanning electron microscopy, energy-dispersive spectroscopy, Raman spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry, we investigated the impact of the electrochemical potential scan range, scan rate, and the number of cycles on electrode response and its ability to detect cadmium and lead. Our findings reveal a 41 ± 1.2% increase in voltammogram currents and a 51 ± 1.6% decrease in potential separations (n = 3), indicating a significantly improved active electrode area and kinetics. The impedance model elucidates the microstructural and electrochemical property changes in the ECP-treated electrodes, showing an 88 ± 2% (n = 3) decrease in the charge transfer resistance, leading to enhanced electrode electrical conductivity. A bismuth-reduced graphene oxide nanocomposite-modified, ECP-treated electrode demonstrated a higher cadmium and lead sensitivity of up to 5 ± 0.1 μAppb−1cm−2 and 2.7 ± 0.1 μAppb−1cm−2 (n = 3), respectively, resulting in sub-ppb limits of detection in spiked deionized water samples. Our study underscores the potential of optimally ECP-activated electrodes as a foundation for designing ultrasensitive heavy metal sensors for a wide range of real-world heavy metal-contaminated waters. [ABSTRACT FROM AUTHOR]

Objective: Metals have been reported to alter the oxidative status of both redox‐active and redox‐inactive metals accompanying oxidative stress induction. In aquatic ecosystems, metal contamination is regarded as serious pollutants and bioaccumulation, especially when aquatic seafood products are involved, which results in human risk. The blue swimming crab Portunus pelagicus is a highly popular crab species for consumption as seafood in Thailand. The meat parts and the hepatopancreas (HP) together with gonad are consumed and in high demand. Therefore, the present study aimed to investigate bioaccumulation of cadmium (Cd) and lead (Pb) along with tissue oxidative responses in P. pelagicus. Methods: Sixty‐seven samples of P. pelagicus were obtained from small‐scale fishers along the coastline of Trang Province. Bioaccumulation of Cd and Pb and oxidative response in gill, muscle, and HP + gonad were evaluated. Result: Cadmium and Pb accumulation levels were highest in the HP and gonad, followed by the gill and then muscle, indicating that Cd and Pb have a high affinity to be concentrated in the HP and gonad. An organ‐specific oxidative response to Cd and Pb accumulation was demonstrated in which Cd significantly activated superoxide dismutase (SOD) activity in the gills and muscle tissue, while Pb significantly activated the SOD activity only in the HP and gonad. Only Cd accumulation in gill tissue represented a significant activation of lipid peroxidation, as indicated by the malondialdehyde level. Conclusion: This study implied that P. pelagicus exhibits an "adaptive stage" in the oxidative response of tissue due to metal accumulation. Additionally, the data presented here further indicate that the consumption of only the meat parts and removal of the HP and gonad would reduce human exposure to metal toxicity. Impact statementThis is the first report to assay oxidative response related to cadmium (Cd) and lead (Pb) accumulation in blue swimming crabs along the coastline of Trang Province, Thailand. The relative organ accumulation levels for Cd and Pb were highest in the hepatopancreas and gonad, followed by the gill and then muscle. [ABSTRACT FROM AUTHOR]

Isotope data of key pollutants are needed for source apportionment analysis in natural ecosystems. Isotope data for cadmium (Cd), a rare and dispersed but toxic element, are very limited mainly due to its low contents in the natural environment. In this study, for samples with low Cd content but high organic matter content, a dry ashing pre-treatment method was proposed to effectively enrich Cd to meet the requirements of its isotope analysis (Cd content > 20 ng). This method was applied to soils, sediments, biological tissues, and coal, with a maximum digestion weight of 1.67 g or more. With the assistance of quartz microfiber filter membranes during dry ashing, good Cd recovery (91.6--108.0%) and significant removal of organic matter were achieved. Mass bias was corrected by combining the silver external standard (Ag-doping) method with the sample-standard-bracketing (SSB) method, and Cd isotope measurements were performed under wet plasma conditions (with an accuracy of 0.060‰). Cd isotopic compositions obtained by the dry ashing method were compared with those obtained by the high-pressure bomb digestion method, and the differences ranged from -0.056 to 0.076‰, indicating that the dry ashing with wrapped membranes method did not cause any fractionation of Cd during the sample pre-treatment process. Meanwhile, the tolerance of tin (Sn) and zinc (Zn) elements provided a significant advantage under wet plasma conditions over dry plasma conditions without reducing the tolerance of molybdenum (Mo) and zirconium (Zr). The method developed in this study should enhance the application of Cd isotopes in investigating Cd cycling in primary ecosystems and organisms. [ABSTRACT FROM AUTHOR]

Cadmium accumulation in wheat as a daily food, even in low concentrations, is a serious threat to human health. Previous studies have reported conflicting results on the impact of calcium treatments on cadmium uptake and translocation in plants due to the complex soil conditions. Our hydroponic study offers clearer insights into how specific calcium treatment parameters influence cadmium uptake and translocation in wheat. The hydroponic medium was contaminated by cadmium (CdCl2) and the following treatments were applied: CaCO3, CaSO4, CaCl2, CaCO3 + CaSO4, CaCO3 + CaCl2, and CaSO4 + CaCl2. After harvesting, the wheat was analyzed for Cd2+ uptake characteristics including translocation factor, bioconcentration factor, and uptake. Furthermore, physiological growth parameters and plant nutrients were also determined. Applying CaCO3 significantly decreased wheat Cd2+ concentration by about three times in CaCO3 and two times in CaCO3 + CaSO4 and CaCO3 + CaCl2 treatments than in Cd-control. This study clearly elucidates that pH and CO32− were crucial in reducing Cd2+ concentration in wheat. SO42−, Cl−, and Ca2+ showed no effect on Cd2+ concentration. Ca2+ only reduced the translocation factor (TF) of Cd2+ in plants. CaCO3 also declined cadmium interference in the Mg2+, Mn2+, and Cu2+ uptake. Therefore, this study provides novel insight into the pure effects of calcium treatments on controlling cadmium contamination in plants, independent of soil effect. [ABSTRACT FROM AUTHOR]

Rice is a major dietary source of the toxic metal cadmium (Cd). Concentration of Cd in rice grain varies widely at the regional scale, and it is challenging to predict grain Cd concentration using soil properties. The lack of reliable predictive models hampers management of contaminated soils. Here, we conducted a three-year survey of 601 pairs of soil and rice samples at a regional scale. Approximately 78.3% of the soil samples exceeded the soil screening values for Cd in China, and 53.9% of rice grain samples exceeded the Chinese maximum permissible limit for Cd. Predictive models were developed using multiple linear regression and machine learning methods. The correlations between rice grain Cd and soil total Cd concentrations were poor (R² < 0.17). Both linear regression and machine learning methods identified four key factors that significantly affect grain Cd concentrations, including Fe-Mn oxide bound Cd, soil pH, field soil moisture content, and the concentration of soil reducible Mn. The machine learning-based support vector machine model showed the best performance (R² = 0.87) in predicting grain Cd concentrations at a regional scale, followed by machine learning-based random forest model (R² = 0.67), and back propagation neural network model (R² = 0.64). Scenario simulations revealed that liming soil to a target pH of 6.5 could be one of the most cost-effective approaches to reduce the exceedance of Cd in rice grain. Taken together, these results show that machine learning methods can be used to predict Cd concentration in rice grain reliably at a regional scale and to support soil management and safe rice production. [ABSTRACT FROM AUTHOR]

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Introduction: There are limited data available regarding the connection between heavy metal exposure and mortality among hypertension patients. Aim: We intend to establish an interpretable machine learning (ML) model with high efficiency and robustness that monitors mortality based on heavy metal exposure among hypertension patients. Methods: Our datasets were obtained from the US National Health and Nutrition Examination Survey (NHANES, 2013–2018). We developed 5 ML models for mortality prediction among hypertension patients by heavy metal exposure, and tested them by 10 discrimination characteristics. Further, we chose the optimally performing model after parameter adjustment by genetic algorithm (GA) for prediction. Finally, in order to visualize the model's ability to make decisions, we used SHapley Additive exPlanation (SHAP) and Local Interpretable Model-Agnostic Explanations (LIME) algorithm to illustrate the features. The study included 2347 participants in total. Results: A best-performing eXtreme Gradient Boosting (XGB) with GA for mortality prediction among hypertension patients by 13 heavy metals was selected (AUC 0.959; 95% CI 0.953–0.965; accuracy 96.8%). According to sum of SHAP values, cadmium (0.094), cobalt (2.048), lead (1.12), tungsten (0.129) in urine, and lead (2.026), mercury (1.703) in blood positively influenced the model, while barium (− 0.001), molybdenum (− 2.066), antimony (− 0.398), tin (− 0.498), thallium (− 2.297) in urine, and selenium (− 0.842), manganese (− 1.193) in blood negatively influenced the model. Conclusions: Hypertension patients' mortality associated with heavy metal exposure was predicted by an efficient, robust, and interpretable GA-XGB model with SHAP and LIME. Cadmium, cobalt, lead, tungsten in urine, and mercury in blood are positively correlated with mortality, while barium, molybdenum, antimony, tin, thallium in urine, and lead, selenium, manganese in blood is negatively correlated with mortality. [ABSTRACT FROM AUTHOR]

Abstract Age-related macular degeneration (AMD) is the leading cause of blindness in older people in developed countries. It has been suggested that heavy metal exposure may be associated with the development of AMD, but most studies have focused on the effects of a single metal with traditional methods. In this study, we analyzed the relationship between 13 urinary heavy metal concentrations and AMD using NHANES data between 2005 and 2008. We constructed and compared 11 machine learning models to identify the best model for predicting AMD risk. We further interpreted the models by Permutation Feature Importance (PFI), Partial Dependence Plot (PDP) analysis, and SHapley Additive exPlanations (SHAP) analysis. 216 AMD patients out of 2380 participants. The random forest (RF) model performed optimally in predicting the risk of AMD, with an AUC value of 0.970. PFI analyses revealed that age and urinary cadmium (Cd) were the main factors influencing the risk of AMD. SHAP analyses further confirmed the significance of Cd concentration in predicting the risk of AMD, and we revealed a significant interaction with significant interaction of race. Our study firstly explored the relationship between heavy metal exposure levels and AMD based on machine learning techniques, found that urinary Cd concentration had the greatest impact on AMD, and revealed the superior predictive performance of machine learning methods. Furthermore, our study provided a new perspective for early screening and intervention of AMD.

Abstract Cadmium contamination in aquatic environments poses severe risks to aquatic organisms, particularly fish, where cadmium accumulation in tissues can lead to compromised organ functionality and reproductive issues. The present study aimed to assess the effects of cadmium (Cd) exposure on key biomarkers of oxidative stress, DNA damage, apoptosis, and enzyme activity in the liver and kidney tissues of rainbow trout (Oncorhynchus mykiss). Specifically, the study measured 8-hydroxy-2-deoxyguanosine (8-OHdG) levels, caspase-3 activation, acetylcholinesterase (AChE) activity, and oxidative stress indicators (ONOO−, MDA, GSH, SOD, and CAT) following exposure to three Cd concentrations (1, 3, and 5 mg/L) over three time points (24, 48, and 96 h). Tissue samples were collected post-exposure, and the analysis revealed a significant decrease in MDA levels in both tissues. GSH concentrations declined with prolonged exposure, while SOD activity increased, indicating a response to oxidative stress, contrasted by a reduction in CAT activity. An initial increase in ONOO− levels was observed at 24 h, followed by a subsequent decrease at the 48 and 96 h marks. These results suggest that cadmium induces oxidative stress in the liver and kidney tissues of fish. Cadmium exposure also significantly elevated 8-OHdG levels, signaling DNA damage, and increased caspase-3 activity, indicative of apoptosis, across all doses and time points (p

Abstract Cadmium (Cd) contamination poses significant risks to agricultural productivity and human health, particularly through its accumulation in staple crops such as bread wheat (Triticum aestivum L.). This study evaluated Cd accumulation and tolerance among six bread wheat cultivars exposed to six Cd concentrations (0, 2.5, 5, 10, 15, 20, and 25 mg kg−1 soil). Phenotypic assessments and quantitative real-time PCR (qRT-PCR) were conducted to analyze the expression patterns of TaNRAMP and TaZIP genes in various tissues and developmental stages of wheat, which play crucial roles in Cd uptake and transport. Results demonstrated significant variability in Cd accumulation. The Barat cultivar exhibited the lowest accumulation in grain (ranging from 0.21 to 8.8 mg kg−1) and the highest tolerance. In contrast, Kavir and Pishtaz displayed elevated Cd levels in both grain and straw, while Parsi accumulated more Cd in straw at lower concentrations (56.9 mg kg−1 in Cd concentration of 10 mg kg−1 soil). The gene expression analysis revealed that most cultivars showed increased expression of TaNRAMP genes, particularly TaNRAMP2 in Cd concentration of 10 mg kg−1 soil, which facilitates Cd uptake from the soil, and TaZIP genes, such as TaZIP4 and TaZIP7, involved in transporting Cd within the plant. Notably, the expression of TaZIP1 was significantly lower in cultivars with high Cd accumulation, suggesting a potential regulatory mechanism for Cd tolerance. Furthermore, cultivars exhibiting higher Cd levels correlated with increased expression of stress-responsive genes, indicating a broader response to Cd stress. These findings highlight Barat’s potential for bread-making applications due to its low Cd accumulation, while Morvarid and Pishtaz which show reduced Cd content in the straw even under high Cd exposure are better suited for animal feed. This research underscores the genetic variability of wheat cultivars in response to Cd stress and provides essential insights into the molecular mechanisms underlying Cd accumulation, offering valuable information for breeding programs aimed at developing Cd-tolerant varieties to ensure food security in contaminated regions.

Dakhla Bay is a paralic environment distinguished by various potentialities, including fishing, aquaculture, and tourism. However, the development of these human activities can lead to negative impacts on this environment, posing a threat to human health. This situation requires special attention to the environment and the implementation of a program for the protection and preservation of this ecosystem. This study aims to identify solutions to protect the marine environment from cadmium contamination by the macroalgae Gracilaria gracilis. The results of cadmium analyses in different compartments of Dakhla Bay, including bivalve molluscs, seawater, sediment, and macroalgae, indicate a difference in cadmium accumulation across the various studied compartments. The highest levels of cadmium are noted in macroalgae, with concentrations ranging from a minimum of 0.9 mg/kg fresh weight in the summer of 2019 to a maximum of approximately 2.55 mg/kg fresh weight recorded during the summer of 2022 at the Lassargua station. In comparison, bivalve molluscs such as Perna perna showed Cd levels ranging from 0.2 mg/kg to 1.4 mg/kg fresh weight at the same station. The sediment samples revealed average Cd levels ranging from 0.02 to 1.39 mg/kg dry weight in samples collected from Lassargua, while seawater concentrations were recorded at approximately 0.65 μg/L. The decontamination of cadmium by the macroalgae Gracilaria gracilis without impacting the quality of the algae has been well confirmed. Indeed, cadmium levels noted in macroalgae remain below the thresholds set by the regulations in force. In conclusion, the results of this study encourage the use of algocultures in Dakhla Bay to protect its ecosystem from various types of pollution.

Abstract Sepiolite-modified nano-zero-valent iron (S-nZVI) is used as an amendment and incubated to remediate As-Cd-contaminated soil under three different soil‒water management conditions [moderately wet (MW), continuously flooded (CF) and alternately wet and dry (AWD)]. The results showed that soil pH is in the order of CF > AWD > MW. The soil pH increased approximately 0.5 to 1 unit by 3% and 5% doses after 36 d of incubation. Soil pH was negatively correlated with available As-Cd content under the three water regimes (p

Abstract Soil amendments play a pivotal role in regulating rhizosphere microbial communities, which is essential for maintaining robust plant growth under adverse environmental conditions. However, the microbial mechanisms that underlie the impact of biochar on phytoremediation performance remain incompletely understood in the context of different application rates. Here, we compared the phytoremediation performance, rhizosphere microbial community characteristics, and microbial interactions in Salix psammophila across different biochar application rates (1%, 3%, 5%, and 7%) in Cd-contaminated soil. Applying 5% biochar increased plant biomass by 10.02%, root activity by 183.82%, and Cd accumulation by 13.65%. Lower biochar rates (1% and 3%) decreased Cd accumulation in plants by 21.89% and 42.05%, respectively, compared to the control. Rhizosphere soil properties and Cd content, except for nitrogen, showed a gradient change with increasing biochar application rates. This was accompanied by an elevation in the Chao1 index for the bacterial community, although the fungal community remained unaffected in terms of diversity and structure. Null-model analyses indicated that fungal community assembly was mainly driven by ecological drift, explaining its unresponsiveness to biochar application. Applying 1% biochar enhanced microbial network stability while reducing bacterial network complexity. Conversely, 3% biochar application resulted in the lowest microbial network stability. Biochar application, except 3%, reduced the proportion of bacteria-fungi associations, suggesting increased independence between two microbial kingdoms. Random forest and piecewise structural equation models revealed that phytoremediation performance is influenced by microbial network stability, complexity, and bacteria-fungi associations. Fungal complexity and stability, along with bacterial stability, were identified as key predictors of phytoremediation performance. Our findings reveal potential mechanisms by which biochar influences phytoremediation through altering microbial interactions. For long-term microbial stability and cost-effectiveness, a 1% biochar application is recommended for phytoremediation. Conversely, for rapid Cd accumulation in plants, a 5% biochar application is optimal. Graphical Abstract

Abstract Background Rapid utilization of natural resources and other anthropogenic activities intruded heavy metals into the food chain and raised alarming concern for all life forms. The available methods proved insufficient in handling waste and pollutants due to the high cost and generation of toxic residues. Bioremediation strategies have offered sustainable solutions for toxic pollutants. In the current study, cadmium and lead (Cd and Pb respectively) tolerant strains have been isolated from industrial effluent and characterized for tolerance towards target pollutants. The strain was identified by 16s rRNA gene and further used for metal removal from the industrial effluents. Results Bacterial isolates were obtained from industrial discharge and evaluated for their tolerance towards Cd and Pb. AS-1 bacterial isolate exhibited maximum tolerance towards both the metals and hence was selected for further study. The isolate was identified as Staphylococcus epidermidis. ICP-MS and energy dispersive X-ray (EDX) analysis of biomass revealed that a significant proportion of cadmium (90.89%) and lead (94.87%) available in effluent were sequestered within bacterial biomass. Characteristic peaks at 2Ɵ (31.8637 and 45.6247 for cadmium) and (21.0397, 27.0127, 46.0537, 54.2707 and 75.6547 for lead) confirmed the crystalline nature of the sequestered metals. The selected strain was characterized on biochemical and molecular basis and was found to be Staphylococcus epidermidis. Based on 16 S rDNA sequence analysis, a phylogenetic dendrogram was created for the maximum likelihood of the bacterial strain. The sequence was deposited in the NCBI repository (accession number PP587422). Conclusion The work has shown the possible way out of heavy metal pollution sustainably. To the best of the author’s knowledge, this is the first report on the sequestration and reduction of cadmium and lead by a nonpathogenic strain of Staphylococcus epidermidis AS-1 that may be useful for alleviating heavy metal contamination.

Abstract A novel technique that couples microbially induced calcite precipitation (MICP) and calcium carbide residue (CCR) is proposed for immobilizing Cd2+ in contaminated soil. The properties and mechanism of CCR-enhanced MICP were investigated through a series of experimental analyses considering factors such as heavy metal concentration, curing time, and the effect of Ca2+. The unconfined compressive strength (UCS) increased with increasing curing time and reached a maximum value at 28 d, and the leaching concentration of Cd2+ decreased and tended to level off with increasing curing time. The addition of CCR enhanced the immobilization performance of Cd2+ through the MICP method, resulting in UCSs that were 3.8–4.2 times those of samples without CCR and leaching concentrations of Cd2+ that were 38.9–69.2% lower at a curing time of 28 d. The addition of Ca2+ to cementation solutions further improved the immobilization effectiveness, resulting in the UCSs of the samples increasing by 18.7–49.8% and the leaching concentrations of Cd2+ decreasing by 11–40% CaCO3 and its hydration products can immobilize Cd2+ through coprecipitation, reducing its toxicity by converting weak acid-extractable cadmium into residual cadmium. Consequently, Sporosarcina pasteurii combined with CCR improved the UCS of the treated contaminated soil and greatly decreased cadmium migration.

Urban environments worldwide face toxic heavy metal pollution originating from industrial discharge, municipal waste disposal, vehicular emissions, and atmospheric deposition. Kazakhstan, experiencing accelerated economic growth and extensive mining activities, contends with widespread heavy metal contamination in its soil-plant-air-water ecosystems. This study explores the potential of hyperaccumulating plants for phytoremediation in urban soils of Kazakhstan contaminated with Pb, Cd, and Co. Twelve plant species, including Korean Mint (Lamiaceae), Ornamental Cabbage (Brassica oleracea), Ageratum (Ageratum houstonianum), Coneflower (Echinacea purpurea), Amaranth (Amaranthus Perfect and Amaranthus Emerald), Fescue (Festuca glauca), Burning Bush (Kochia scoparia), Marigold (Tagetes patula nana), White Cabbage (Brassica-Cavolo cappuccino BIANKO), Tepary Bean (Phaseolus acutifolius), and Rapeseed (Brassica napus), were evaluated for growth and biomass production in urban soils spiked with two maximum permissible addition (MPA) treatments of Pb, Co, and Cd. The selected plants demonstrated varied responses to heavy metal stress, with Marigold (8.4 g shoot biomass/plant), Korean mint (10.5 g shoot biomass/plant), Rapeseed (19.9 g/shoot biomass), and Tepary bean (25.9 g shoot biomass/plant) exhibiting resilience or tolerance to Pb, Co, and Cd stresses. The results highlight the significant potential of these plants for efficient phytoremediation, showcasing their unique abilities to absorb and accumulate specific metals. Marigold, particularly, displayed noteworthy Pb accumulation (40.3 mg/kg biomass), resulting in reduced residual Pb concentrations in the soil (74.7 mg/kg). Conversely, White cabbage and Amaranth showed limited efficiency in Cd extraction, while Rapeseed and Tepary bean emerged as promising candidates for Cd phytoremediation. This study emphasizes the critical role of tailored plant species selection in designing effective phytoremediation strategies for specific metal-contaminated urban sites. A comprehensive understanding of the dynamics of metal accumulation and residual concentrations is crucial for the development of sustainable and efficient environmental remediation approaches. Further research is warranted to explore the long-term effects of different plant species on soil metal concentrations, refining and optimizing phytoremediation methods for urban soils grappling with toxic heavy metal contamination

BACKGROUND AND OBJECTIVES: The presence of heavy metals, specifically cadmium, in the environment poses significant threats to both ecological systems and human health. However, microalgae have shown potential in addressing this issue through their ability to absorb cadmium and produce valuable biomass, making them a promising solution for bioremediation. Among the various microalgae species, Chlorella vulgaris stands out as a suitable candidate due to its potential for biodiesel production and its capacity to effectively absorb cadmium. Therefore, the main objective of this study is to assess the toxicity of cadmium on Chlorella vulgaris cells using network meta-analysis as a methodology.METHODS: A comprehensive search was conducted on Scopus, Scilit, Google Scholar, and Web of Science to identify relevant studies published from 1 January 1990 to 16 January 2024. Only studies that reported the cell number of Chlorella vulgaris as a result of cadmium exposure were considered for inclusion. The collected data were then subjected to Bayesian frequentist network meta-analysis, utilizing standardized mean difference and a 95 percent confidence interval as measures of effect size. Additionally, a linear regression analysis was performed to examine the dose-dependent impact of cadmium toxicity.FINDINGS: Dose-dependent toxic effects of cadmium on Chlorella vulgaris were evident (R-square of more than 0.90), particularly at a concentration of 1 part per million, deemed as the maximum tolerable threshold. Prolonged exposure revealed a concentration-dependent reduction in cell viability, suggesting potential lifespan shortening. A comparison of growth stimulants, gibberellic acid and brassinolide (standard means differences of 1.7 and 3.8, respectively), in mitigating cadmium toxicity indicated the latter superior effectiveness in sustaining microalgal survivability. The presence of high nitrogen and low phosphorous levels was found to be significantly associated with a reduction in Chlorella vulgaris cells due to cadmium exposure.CONCLUSION: This research has provided conclusive proof of the harmful effects of cadmium on Chlorella vulgaris through the implementation of Bayesian frequentist network meta-analysis, offering valuable insights for environmental management practices. The findings reveal concentration-dependent effects of cadmium toxicity. The survivability of Chlorella vulgaris is determined by the compositions of macronutrients nitrogen and phosphorous. Comparative analyses highlight the superior protective effect of brassinolide over gibberellic acid in mitigating cadmium toxicity. Overall, the findings highlight the potential of Chlorella vulgaris in both bioremediation of heavy metals and biomass production.

Cadmium is one of the heavy metals with high toxicity that can harm human health and the environment. A commonly used method to remove heavy metals is adsorption. One of the widely used adsorbents is zeolite, which is composed primarily of silica and alumina. Palm oil fly ash (POFA) is a waste from palm oil mills that is rich in silica and alumina so that it can be used as a basic material for zeolite. This research aims to study the factors that affect the adsorption process of Cd metal using zeolite synthesized from POFA and determine the kinetics and isotherms of adsorption. The factors observed were pH (3, 4, 5, 6; 7), adsorbent dosage (1, 1.5, 2, 2.5, 3 g/l), contact time (5, 10, 15, 30, 60, 90, 120, 150, 180 min), and initial concentration of Cd metal (2, 4, 6, 8, 10, 15 mg/L). Adsorbent characterization was performed by XRF and XRD analysis. The results showed that pofa-based zeolite can remove Cd metal with an efficiency above 95%. The adsorption process can follow well the pseudo-second-order kinetics model and both Langmuir and Freundlich isotherm models with a maximum adsorption capacity of 64.58 mg/g. The zeolite synthesized from POFA can remove Cd metal well and has the potential to be developed into an adsorbent

Abstract Background Exposure to cadmium (Cd) is associated with a reduction in lung function among patients with chronic obstructive pulmonary disease (COPD). The longitudinal relationship and mechanism underlying the link between Cd exposure and lung function changes among COPD patients are yet unknown. Methods The cohort study included 259 eligible patients who underwent regular professional follow-ups. Blood Cd levels and serum 8-iso-prostaglandin F2 alpha (8-iso-PGF2α) levels were assessed. Lung function was determined at baseline and follow-up research. The associations between changes in lung function and blood Cd concentration were analysed using multivariate linear and logistic regression models. Results Each 1-ppb elevation in blood Cd content resulted in a 0.420 L decrease in forced vital capacity (FVC), a 0.424 L decrease in forced expiratory volume in 1 s (FEV1), a 4.341% decrease in FEV1/FVC%, and a 8.418% decrease in FEV1% predicted in patients with COPD. Blood Cd concentration showed a positive correlation with serum 8-iso-PGF2α levels in a specific range. The relative contribution of increased serum levels of 8-iso-PGF2α to Cd-induced declines in FEV1, predicted FEV1%, and FEV1/FVC% were 2.08%, 8.08%, and 13.19%, respectively. Conclusion Blood Cd levels are associated with lung function changes in COPD patients. Oxidative stress is thought to be an important mediator in Cd-induced reduction of pulmonary function.

Abstract This project utilized both field experiment and laboratory analyses to address the gap in understanding regarding the alterations in properties and functions of biochar, and the impact of heavy metal passivation in soil over long-term natural field aging. The study aimed to examine the changes in the physical and chemical characteristics of biochar over an extended period of natural aging. Additionally, it sought to analyze the impact and mechanisms of biochar in reducing of the harmful effects of the heavy metal cadmium (Cd) during the aging process. Both original and aged biochar conformed to the pseudo-second-order kinetics model and the Langmuir model. The aging process enhanced the adsorption of Cd by biochar and mitigated the leaching of Cd2+ into the soil. These findings provide a scientific basis for evaluating biochar’s environmental behavior and its potential use in the remediation of soil contaminated with heavy metals.

Toxic metal wastewater is a challenge for exposed terrestrial and aquatic environments, as well as the recyclability of the water, prompting inputs for the development of promising treatment methods. Consequently, the rGO/ZnONP nanocomposite was synthesized at room temperature for four hours and was tested for the adsorption of cadmium and lead in wastewater. The optimized nanocomposite had the lowest band gap energy (2.69 eV), and functional group interactions were at 516, 1220, 1732, 3009, and 3460 cm−1. The nanocomposite showed good ZnO nanoparticle size distribution and separation on rGO surfaces. The nanocomposite’s D and G band intensities were almost the same, constituting the ZnO presence on rGO from the Raman spectrum. The adsorption equilibrium time for cadmium and lead was reached within 10 and 90 min with efficiencies of ~100%. Sips and Freundlich best fitted the cadmium and lead adsorption data (R2 ~ 1); therefore, the adsorption was a multilayer coverage for lead and a mixture of heterogenous and homogenous coverage for cadmium adsorption. Both adsorptions were best fitted by the pseudo-first-order model, suggesting the multilayer coverage dominance. The adsorbent was reused for three and seven times for cadmium and lead. The nanocomposite showed selectivity towards lead (95%) and cadmium (100%) in the interfering wastewater matrix. Conclusively, the nanocomposite may be embedded within upcoming lab-scale treatment plants, which could lead to further upscaling and it serving as an industrial wastewater treatment material.

Abstract Rice grown in cadmium (Cd)-contaminated soil, is a potential threat to human health, but exogenous selenium (Se) application on rice can mitigate Cd toxicity. However, the mechanisms underlying Se mitigation of Cd stress in ratoon rice (RR) are still poorly understood. We conducted a pot experiment with moderate Cd-contaminated yellow–brown paddy soil on two rice varieties ‘Taoyouxiangzhan’ (TX) and ‘Liangyou 6326’(LY). For all treatments, 1.0 mg kg−1 sodium selenite solution was added to soil. Treatment T1 was sodium selenite only, and in the other treatments 100 mg L−1 Se solution was sprayed on the leaves at seedling stage (T2), at tillering stage (T3), and in early anthesis stage (T4). Se treatments decreased Cd accumulation in rice grains and herbage. Under foliar spraying 100 mg L−1 Se at the seedling + 1.0 mg kg−1 Se in soil (T2), leaf Cd content decreased 16.95% in the current season and grains content decreased 46.67% in the subsequent season. Furthermore, grain Se content increased 0.94 mg kg−1 for the TX variety combined with the analysis of Cd bio-accumulation factor in grains, and Se treatments effectively decreased Cd grain concentrations due to reduced Cd translocation from roots to grains. TX variety rice showed a more pronounced response to Se treatments than LY.

The article is devoted to the problem of choosing informative indicators of the ecological state of soil with a low stress factor. The purpose of this work is to compare toxicological (ex situ) and bioindicative indicators (in situ) of soil under conditions of pollution, drought, and increased acidity. The number of zymogenic and oligotrophic microflora, the activity of catalase and urease exoenzymes, including the acute toxicity of soil extracts in tests for Paramecium caudatum and Escherichia coli were determined in soil samples. Most of the reactions observed ex situ and in situ were hormetic or equal to the control. As compared to the control, an increase in the number was noted in oligocarbophiles in moderately acidic soil (by 13 times), in oligotrophs in drought-exposed soil (by 22 times), in amylolytics in contaminated and acidic soil (by 6 times), as well as in arid soil (by 1.6 times). The values of the following parameters significantly decreased in the conditions of the applied factors: the number of ammonifiers under low-level cadmium stress (by 3 times) and moderate soil acidity (by 5 times), cellulolytics in response to soil acidity (by 2.5 times) and under drought (by 1.7 times), urease activity in moderately acidic soil (by 1.7 times). In addition, the toxicity index for moderately acidic soil in the test for P. caudatum increased by 1.4 times.

Although brain-machine interfaces (BMIs) are directly controlled by the modulation of a select local population of neurons, distributed networks consisting of cortical and subcortical areas have been implicated in learning and maintaining control. Previous work in rodents has demonstrated the involvement of the striatum in BMI learning. However, the prefrontal cortex has been largely ignored when studying motor BMI control despite its role in action planning, action selection, and learning abstract tasks. Here, we compare local field potentials simultaneously recorded from primary motor cortex (M1), dorsolateral prefrontal cortex (DLPFC), and the caudate nucleus of the striatum (Cd) while nonhuman primates perform a two-dimensional, self-initiated, center-out task under BMI control and manual control. Our results demonstrate the presence of distinct neural representations for BMI and manual control in M1, DLPFC, and Cd. We find that neural activity from DLPFC and M1 best distinguishes control types at the go cue and target acquisition, respectively, while M1 best predicts target-direction at both task events. We also find effective connectivity from DLPFC → M1 throughout both control types and Cd → M1 during BMI control. These results suggest distributed network activity between M1, DLPFC, and Cd during BMI control that is similar yet distinct from manual control.

Reproduction is key to the survival and development of a species. Anthropogenic activities release significant amounts of toxic pollutants into the environment. In this study, we aimed to determine effects of heavy metals on some reproductive parameters of the mountain hare. Female mountain hares (n = 41) were hunted in the reference and industrially polluted areas of Krasnoyarsk Krai during four seasons. Their skeletal muscles, liver, and kidneys were subjected to atomic absorption spectrometry to determine concentrations of lead, cadmium, and mercury. The contents of lead, cadmium, and mercury were significantly higher in the hares from the contaminated areas compared to the reference sites. According to the results, the exposure to lead, cadmium, and mercury had an impact on the reproductive potential of the female mountain hares. In particular, we established correlations between numbers of embryos and corpora lutea and contents of lead in the kidneys and liver, as well as cadmium in the kidneys. The number of corpora lutea and embryonic losses in the female hares from the contaminated areas were higher than those in the hared from reference areas. However, the numbers of embryos did not differ significantly between the compared areas. Our study showed that about 40% of the liver samples and 100% of the muscle tissue samples obtained from the hares in the impact zone contained high concentrations of lead and cadmium. Therefore, hunting in these industrially polluted areas may pose a toxic hazard to the indigenous peoples living there. Further research is needed to assess potential and actual fertility, offspring survival, and other important parameters of mountain hare populations exposed to different levels of chemical pollution.