A global perspective on cadmium pollution and toxicity in non-occupationally exposed population

Dual Fluorimetric Sensor for Tandem Detection of Cadmium and Cysteine: An Approach for Designing a Molecular Keypad Lock System

A fluorimetric sensor for dual and sensitive detection of Cd2+ ion and Cysteine (based on 2-picolylamine platform) was developed.The sensor was designed and synthesized by simple condensation method and characterized by using common spectroscopic methods. The observations made from the kinetics of absorption and emission profile shows that probe Pdac behaves as ''ON-OFF'' fluorescent quenching sensor for cadmium ions. The probe exhibit selectivity in fluorescence quenching behaviour over other competitive metal ions, and also the Pdac-Cd2+ ensemble behave as an efficient ''OFF-ON'' type sensor for an essential amino acid Cysteine. Moreover, this dual sensing nature of the sensor makes it successfully applied for the designing of a molecular keypad lock system.

Prenatal metal(loid) exposure and preterm birth: a systematic review of the epidemiologic evidence

BACKGROUND

Preterm birth (PTB) is a common pregnancy complication associated with significant neonatal morbidity. Prenatal exposure to environmental chemicals, including toxic and/or essential metal(loid)s, may contribute to PTB risk.

OBJECTIVE

We aimed to summarize the epidemiologic evidence of the associations among levels of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), manganese (Mn), lead (Pb), and zinc (Zn) assessed during the prenatal period and PTB or gestational age at delivery; to assess the quality of the literature and strength of evidence for an effect for each metal; and to provide recommendations for future research.

METHODS

We adapted the Navigation Guide methodology and followed PRISMA guidelines. We searched the MEDLINE/PubMed database for epidemiologic studies from 1995 to 2023. We used a customized risk of bias protocol and evaluated the sufficiency of evidence for an effect of each metal(loid) on PTB risk.

RESULTS

A total of 1206 studies were identified and screened. Of these, 139 were assessed for eligibility by reading the full-text, and 92 studies were ultimately included (arsenic: 40, cadmium: 30, chromium: 11, copper: 21, mercury: 27, manganese: 17, lead: 41, zinc: 18, metal(loid) mixtures: 12). We found sufficient evidence that lead increases the risk of PTB and, while the evidence was limited, suggestive evidence that cadmium and chromium increase the risk of PTB. The evidence was deemed inadequate to determine an effect for the other metal(loid)s.

SIGNIFICANCE

Future research would benefit from more precise PTB clinical phenotyping, measuring exposure early and longitudinally throughout pregnancy, using an appropriate media for metal(loid)s under study, and evaluating metal mixtures. Given the strength of evidence linking lead exposure and PTB, active and comprehensive prenatal screening for lead exposure among pregnant individuals is warranted.

IMPACT

By summarizing 92 epidemiologic studies that investigated the associations between metal exposure and preterm birth using the rigorous Navigation Guide methodology, our review provides compelling evidence for a strong link between prenatal lead exposure and preterm birth. Additionally, it suggests potential associations between cadmium and chromium exposure and preterm birth. Given the robust nature of this evidence, there is an urgent need for prenatal screening for lead exposure during pregnancy, along with targeted interventions to reduce exposure. These actions are critical for advancing maternal and child health.

Over-expression of LsEXPA6, a lettuce expansin gene, improves cadmium stress tolerance in transgenic Arabidopsis

Cadmium (Cd) is a harmful heavy metal that is highly toxic to plants and animals. Expansins are cell wall proteins inducing cell wall loosening and participate in all plant growth and development processes which are associated with cell wall modifications. We investigated lettuce's expansin gene LsEXPA6 and found that LsEXPA6 overexpression Arabidopsis lines were much more resistant to cadmium stress. Our results revealed that the root system of the expa6 mutant was suppressed under cadmium stress, resulting in shorter plant height, reduced biomass, and a significant increase in cadmium content in the plants compared with wild-type plants, whereas LsEXPA6 overexpression lines had a well-developed root system and reduced cadmium accumulation in the roots and shoots of the plants. The above results indicated that overexpression of LsEXPA6 affected root development and reduced Cd absorption in Arabidopsis. In addition, the higher absorption capacity of nutrients, increased antioxidant enzymes activities, improved chlorophyll and photosynthetic function in the overexpression Arabidopsis plants, supported the Cd stress tolerance mechanism. Taken together, these results provided a new insight on the role of expansin proteins in the tolerance of plants to Cd stress by root cell elongation.

Mechanistic role for mTORC1 signaling in profibrotic toxicity of low-dose cadmium

Cadmium (Cd) is a toxic environmental metal that occurs naturally in food and drinking water. Cd is of increasing concern to human health due to its association with age-related diseases and long biological half-life. Previous studies show that low-dose Cd exposure via drinking water induces mechanistic target of rapamycin complex 1 (mTORC1) signaling in mice; however, the role of mTORC1 pathway in Cd-induced pro-fibrotic responses has not been established. In the present study, we used human lung fibroblasts to examine whether inhibiting the mTORC1 pathway prevents lung fibrosis signaling induced by low-dose Cd exposure. Results show that rapamycin, a pharmacological inhibitor of mTORC1, inhibited Cd-dependent phosphorylation of ribosomal protein S6, a downstream marker of mTORC1 activation. Rapamycin also decreased Cd-dependent increases in pro-fibrotic markers, α-smooth muscle actin, collagen 1α1 and fibronectin. Cd activated mitochondrial spare respiratory capacity in association with increased cell proliferation. Rapamycin decreased these responses, showing that mTORC1 signaling supports mitochondrial energy supply for cell proliferation, an important step in fibroblast trans-differentiation into myofibroblasts. Collectively, these results establish a key mechanistic role for mTORC1 activation in environmental Cd-dependent lung fibrosis.

Unveiling the Potential of Sulfur-Rich Macrocyclic Chelators Against Cadmium Poisoning

Cadmium, an extremely toxic heavy metal, poses significant health risks to humans. Despite persistent research efforts, the development of effective treatments for cadmium intoxication remains a challenge. This study aims to establish the chemical groundwork for improved chelation therapy options against cadmium poisoning. Herein, the coordination chemistry of a series of sulfur-rich macrocycles featuring different polyamine backbones (NO3S, TACD3S, DO4S, TRI4S, and TE4S) was investigated. Our results demonstrate that DO4S exhibits exceptional Cd2+ scavenging ability, forming the most thermodynamically stable complex among the studied chelators. The stability of the Cd2+ complexes decreases in the following order: DO4S (pCd = 19.8) ≫ NO3S (pCd = 11.0) ∼ TRI4S (pCd = 10.9) ≫ TE4S (pCd = 7.8) > TACD3S (pCd = 7.3). DFT calculations demonstrated that the backbone polarization properties dictate the observed reduced stability when shifting from DO4S to the other ligands. DO4S showed superior affinity when compared to the state-of-the-art Cd2+ chelators such as EDTA (pCd = 16.7), DTPA (pCd = 17.4), and DMSA (pCd = 13.2). The findings from this study underscore the potential of the examined chelating agents, with particular reference to DO4S, paving the way for the development of advanced chelation therapies to combat cadmium poisoning.

Low-level, chronic ingestion of lead and cadmium: The unspoken danger for at-risk populations

The long-term effects of low-level, chronic exposure to lead and cadmium through ingestion are often overlooked, despite the urgency surrounding the clinical onset and worsening of certain pathologies caused by these metals. This work reviews current legislation, global ingestion levels, and blood levels in the general population to emphasize the need for reactivity towards this exposure, especially in at-risk populations, including patients with early-stage renal and chronic kidney disease. Global data indicates persistent chronic ingestion of lead and cadmium, with no decreasing trend in recent years, and a daily consumption of tens of micrograms worldwide. Moreover, the average blood lead and cadmium levels in the general population are concerning in many countries with some significantly exceeding healthy limits, particularly for children. Technologies developed to cleanse soil and prevent heavy metal contamination in food are not yet applicable on a global scale and remain financially inaccessible for many communities. Addressing this chronic ingestion at the human level may prove more beneficial in delaying the onset of associated clinical pathologies or preventing them all together.

Cadmium uptake and detoxification in tomato plants: Revealing promising targets for genetic improvement

Cadmium (Cd) is a hazardous heavy metal known for its detrimental effects on plants, human health, and the environment. This review article delves into the dynamics of Cd uptake, long-distance transport, and its impact on plant performance, with a specific focus on tomato plants. The process of Cd uptake by roots and its subsequent long-distance transport in the xylem and phloem are explored to understand how Cd influences plants operation. The toxic effects of Cd on tomato plants are discussed, highlighting on the challenges it poses to plant growth and development. Furthermore, the review investigates various Cd tolerance mechanisms in plants, including avoidance or exclusion by the root cell wall, root-to-shoot translocation, detoxification pathways, and antioxidative defence systems against Cd-induced stress. In addition, the transcriptomic analyses of tomato plants under Cd stress provide insights into the molecular responses and adaptations of plants to Cd toxicity. Overall, this comprehensive review enhances our understanding of Cd-plant interactions and reveal promising genes for tomato genetic improvement to increase its tolerance to cadmium.

Efficacy of Agricultural Residue-Derived Biochar for Tackling Cadmium Contamination in an Aqueous Solution

This study aimed to investigate the efficacy of biochar, produced from different agricultural residues varying in lignin and cellulose content and subjected to different pyrolysis temperatures, in removing cadmium ions (Cd (II)) from an aqueous solution. This removal process is crucial for protecting human health and the environment. Specifically, the study focused on the adsorption behaviors of Cd (II) by the biochars made from rice husk biochar (RHB), maize straw biochar (MSB), peanut shell biochar (PSB), cottonseed shell biochar (CHB), and mulberry leaf biochar (MLB), which were prepared at 300 °C and 600 °C. The results indicated that the type of agricultural residue used to produce biochar significantly influenced the adsorption of Cd (II). Notably, mulberry leaf biochar prepared at 300 °C (MLB-300) demonstrated the highest adsorption efficiency, achieving a maximum adsorption capacity of 42.2 mg g-1. Batch adsorption experiments assessed the impact of various factors, including system pH, NO3- concentration, and adsorption duration. The adsorption kinetics were better described by the pseudo-second-order model than the pseudo-first-order model. Moreover, the study found that the lignin content of the biochar plays a major role in determining the adsorption capacity. The surface characteristics of biochar, influenced by the types of agricultural residues and preparation temperature, directly impact its adsorption mechanism and capacity. While biochar produced at 300 °C showed optimal Cd(II) adsorption, those processed at 600 °C were less effective, likely due to the loss of functional groups at higher temperatures.

Nano‑selenium alleviates cadmium-induced blood-brain barrier destruction by restoring the Wnt7A/β-catenin pathway

Selenium (Se), a highly beneficial animal feed additive, exhibits remarkable antioxidant and anti-inflammatory properties. Nano‑selenium (Nano-Se) is an advanced formulation of Se featuring a specialized drug delivery vehicle, with good bioavailability, higher efficacy, and lower toxicity compared to the traditional form of Se. With the advancement of industry, cadmium (Cd) contamination occurs in different countries and regions and thereby contaminating different food crops, and the degree of pollution is degree increasing year by year. The present investigation entailed the oral administration of CdCl2 and/or Nano-Se to male chickens of the Hy-Line Variety White breed, which are one day old, subsequent to a 7-day adaptive feeding period, for a duration of 90 days. The study aimed to elucidate the potential protective impact of Nano-Se on Cd exposure. The study found that Nano-Se demonstrates potential in mitigating the blood-brain barrier (BBB) dysfunction characterized by impairment of adherens junctions (AJS) and tight junctions (TJS) by inhibiting reactive oxygen species (ROS) overproduction. In addition, the data uncovered that Nano-Se demonstrates a proficient ability in alleviating BBB impairment and inflammatory reactions caused by Cd through the modulation of the Wnt7A/β-catenin pathway, highlights its potential to maintain brain homeostasis. Hence, this research anticipates that the utilization of Nano-Se effectively mitigate the detrimental impacts associated with Cd exposure on the BBB.

Oceanobacillus picturae alleviates cadmium stress and promotes growth in soybean seedlings

Cadmium (Cd) is a heavy metal that significantly impacts human health and the environment. Microorganisms play a crucial role in reducing heavy metal stress in plants; however, the mechanisms by which microorganisms enhance plant tolerance to Cd stress and the interplay between plants and microorganisms under such stress remain unclear. In this study, Oceanobacillus picturae (O. picturae) was isolated for interaction with soybean seedlings under Cd stress. Results indicated that Cd treatment alone markedly inhibited soybean seedling growth. Conversely, inoculation with O. picturae significantly improved growth indices such as plant height, root length, and fresh weight, while also promoting recovery in soil physiological indicators and pH. Metabolomic and transcriptomic analyses identified 157 genes related to aspartic acid, cysteine, and flavonoid biosynthesis pathways. Sixty-three microbial species were significantly associated with metabolites in these pathways, including pathogenic, adversity-resistant, and bioconductive bacteria. This research experimentally demonstrates, for the first time, the growth-promoting effect of the O. picturae strain on soybean seedlings under non-stress conditions. It also highlights its role in enhancing root growth and reducing Cd accumulation in the roots under Cd stress. Additionally, through the utilization of untargeted metabolomics, metagenomics, and transcriptomics for a multi-omics analysis, we investigated the impact of O. picturae on the soil microbiome and its correlation with differential gene expression in plants. This innovative approach unveils the molecular mechanisms underlying O. picturae's promotion of root growth and adaptation to Cd stress.

Fluorescent, phosphorescent, magnetic resonance contrast and radioactive tracer labelling of extracellular vesicles

This review focusses on the significance of fluorescent, phosphorescent labelling and tracking of extracellular vesicles (EVs) for unravelling their biology, pathophysiology, and potential diagnostic and therapeutic uses. Various labeling strategies, such as lipid membrane, surface protein, luminal, nucleic acid, radionuclide, quantum dot labels, and metal complex-based stains, are evaluated for visualizing and characterizing EVs. Direct labelling with fluorescent lipophilic dyes is simple but generally lacks specificity, while surface protein labelling offers selectivity but may affect EV-cell interactions. Luminal and nucleic acid labelling strategies have their own advantages and challenges. Each labelling approach has strengths and weaknesses, which require a suitable probe and technique based on research goals, but new tetranuclear polypyridylruthenium(II) complexes as phosphorescent probes have strong phosphorescence, selective staining, and stability. Future research should prioritize the design of novel fluorescent probes and labelling platforms that can significantly enhance the efficiency, accuracy, and specificity of EV labeling, while preserving their composition and functionality. It is crucial to reduce false positive signals and explore the potential of multimodal imaging techniques to gain comprehensive insights into EVs.

Material flow analysis of heavy metals in large-scale cattle farms and ecological risk assessment of cattle manure application to fields

This study bridges the knowledge gap pertaining to the pathways of heavy metal accumulation and migration within the industrial chain of large-scale cattle farms. Two such farms in Shaanxi serve as a basis for our exploration into Zn, Cu, Cr, Pb, As, and Cd dynamics. Employing material flow analysis complemented by predictive models, we evaluate the potential ecological risks of arable soil from heavy metal influx via manure application. Our findings indicate that Zn and Cu predominate the heavy metal export from these operations, composing up to 60.00%-95.67% of their total content. Predictive models based on 2021 data reveal a potential increase in Cd soil concentration by 0.08 mg/kg by 2035, insinuating a reduced safe usage period for cattle manure at less than 50 years. Conversely, projections from 2022 data point towards a gradual Cu rise in soil, reaching risk threshold levels after 126 years. These outcomes inform limitations in cattle manure utilisation strategies, underscoring Cu and Cd content as key barriers. The study underscores the criticality of continuous heavy metal surveillance within farm by products to ensure environmental protection and sustainable agricultural practices.

Cadmium aggravates liver injury by activating ferroptosis and neutrophil extracellular traps formation in Nile tilapia (Oreochromis niloticus)

Cadmium (Cd) is a pervasive environmental contaminant and a significant risk factor for liver injury. The present study was undertaken to evaluate the involvement of ferroptosis and neutrophil extracellular traps (NETs) in Cd-induced liver injury in Nile tilapia (Oreochromis niloticus), and to explore its underlying mechanism. Cd-induced liver injury was associated with increased total iron, malondialdehyde (MDA), and Acyl-CoA synthetase long-chain family member 4 (ACSL4), together with reduced levels of glutathione, glutathione peroxidase-4a (Gpx4a), and solute carrier family 7 member 11 (SLC7A11), which are all hallmarks of ferroptosis. Moreover, liver hyperemia, neutrophil infiltration, increased inflammatory factors and myeloperoxidase, as well as elevated serum DNA content in Cd-stimulated Nile tilapia suggested that a considerable number of neutrophils were recruited to the liver. Furtherly, in vitro experiments demonstrated that Cd induced the formation of NETs, and the possible mechanism was related to the generation of reactive oxygen species and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, along with the P38 and extracellular regulated protein kinase (ERK) signaling pathways. We concluded that ferroptosis and NETs are the critical mechanisms contributing to Cd-induced liver injury in Nile tilapia. These findings will contribute to Cd toxicological studies in aquatic animals.

The possible application of fly ash (FA) to ameliorate acid mine water (AMD) for irrigation of potato (Solanum tuberosum L.)

Some areas in Johannesburg abounds with mine wastes namely, acid mine drainage (AMD) as well as fly ash (FA), which are by-products of gold mining and coal burning, respectively. Studies show that a solution formed through mixing these wastes neutralises the acidity of AMD and is an alternative source of irrigation. While studies show improved growth and yield of plants irrigated with fly ash-amended AMD, there are rarely sufficient studies conducted in South Africa showing evidence of altered pH of AMD and that food crops irrigated with fly ash-amended AMD exhibit improved concentration of essential nutrient elements. In this study, AMD was sourced from a gold mine in Johannesburg and fly ash collected from a coal-burning power station in the Mpumalanga Province, mixed at 1:0, 1:1, and 3:1 (w/v) of fly ash to AMD and used to irrigate potatoes. The objective was to assess whether the solutions of FA-amended AMD alter the pH of the AMD and to evaluate if irrigating potatoes with the aforementioned improve the concentration of essential nutrient elements and heavy metals in the tubers. Results show that the pH of AMD was increased in the 1:0 and 1:1 solutions but decreased in the 3:1 solution. The concentrations of Pb and Co were decreased in tubers irrigated with the 50 % AMD and 75 % AMD while that of Ni and Cd were markedly increased in tubers irrigated with solutions of fly ash-amended AMD. In the main, the potato tubers exhibited significantly higher concentrations of Al, Mo, Cu, Ca, Mg, and Zn when irrigated with fly-ash-amended AMD. The pH range levels from FA-AMD treated samples were within the acceptable pH range (5.5-6.5) which is acceptable for water that could be used for irrigation of crops. Also, the decreased Co and Pb and improved concentration of essential nutrient elements indicate that the constituents absorbed large quantities of the heavy metals while releasing the nutrients. In conclusion, the selected fly ash has proven as an alternative low-cost readily-available, affordable, and accessible adsorbent that neutralize the acidity of AMD, decrease the concentration of heavy metals, and increase the concentration of essential nutrient elements. Importantly, the liming potential among other traits of the fly ash improved the quality of the AMD such that the wastes were proven in this study suitable to irrigate potatoes.

Possible enrichment process of Cd in the Se-rich soil area of Lanshan District, Shandong Province, China

High cadmium (Cd) concentrations widely occured in selenium (Se)-rich soils, which has been an important obstacle in the usage of Se-rich soils. There is still no special information detailing the enrichment process and mechanism of Cd in Se-rich soils. 4474 soils and 21 rocks in Lanshan District were sampled to detect its enrichment process. The surface soils have Cd concentrations of 0.01-9.41 mg·kg-1 (an average of 0.16 mg·kg-1). The soil Cd concentrations were significantly correlated with soil Se concentrations. The relatively higher-Cd surface soils are distributed in Lower-middle Ordovician carbonate areas with Se-rich soils and Quaternary areas with typical anthropic activities. Surface soils in Ordovician carbonate area have the highest Cd concentrations. Soil Cd concentrations are significantly correlated with sulfophil elements (Zinc (Zn), Copper (Cu), Molybdenum (Mo), Lead (Pb) and Arsenic (As) etc.), Ca (Calcium) concentrations and soil organic carbon (SOC). The soil and rock samples from different geological units also confirmed soil Cd concentrations developing from Ordovician carbonates were higher than those from other rocks. The results indicate the soil Cd concentrations were the complex consequences of bedrock, soil-forming processes and anthropogenic activities. Higher Ca concentrations and more reduction environments result in high-Cd bedrock. CaCO3 leaching and alkaline pH, which are the special soil-forming process of carbonates, enrich Cd in soils. Agricultural and industrial activities also affect soil Cd concentrations. An enrichment model of Cd in Se-rich soils is forwarded.

Cadmium toxicity and autophagy: a review

Cadmium (Cd) is an important environmental pollutant that poses a threat to human health and represents a critical component of air pollutants, food sources, and cigarette smoke. Cd is a known carcinogen and has toxic effects on the environment and various organs in humans. Heavy metals within an organism are difficult to biodegrade, and those that enter the respiratory tract are difficult to remove. Autophagy is a key mechanism for counteracting extracellular (microorganisms and foreign bodies) or intracellular (damaged organelles and proteins that cannot be degraded by the proteasome) stress and represents a self-protective mechanism for eukaryotes against heavy metal toxicity. Autophagy maintains cellular homeostasis by isolating and gathering information about foreign chemicals associated with other molecular events. However, autophagy may trigger cell death under certain pathological conditions, including cancer. Autophagy dysfunction is one of the main mechanisms underlying Cd-induced cytotoxicity. In this review, the toxic effects of Cd-induced autophagy on different human organ systems were evaluated, with a focus on hepatotoxicity, nephrotoxicity, respiratory toxicity, and neurotoxicity. This review also highlighted the classical molecular pathways of Cd-induced autophagy, including the ROS-dependent signaling pathways, endoplasmic reticulum (ER) stress pathway, Mammalian target of rapamycin (mTOR) pathway, Beclin-1 and Bcl-2 family, and recently identified molecules associated with Cd. Moreover, research directions for Cd toxicity regarding autophagic function were proposed. This review presents the latest theories to comprehensively reveal autophagy behavior in response to Cd toxicity and proposes novel potential autophagy-targeted prevention and treatment strategies for Cd toxicity and Cd-associated diseases in humans.

Effect of cadmium on histopathological injuries and ultra-structural changes of kidney of the turtle Mauremys reevesii

This research investigated the effect of cadmium on the tissue and cell of kidney of the turtle Mauremys reevesii. Twenty turtles were injected with cadmium at 0, 7.5, 15, 30 mg/kg separately and five turtles were taken in each group at two weeks after exposure. Kidneys were immediately excised and macroscopic pathological changes were observed, then the kidneys were fixed in 4% paraformaldehyde for histopathological examination and fixed in 2.5% (v/v) glutaraldehyde for examination of ultra-structure. The tissues of kidney presented varying degrees of histopathological lesions in cadmium treated turtles by a dose-dependent manner under the light microscope. Under transmission electron microscope, renal tubules cells presented varying degrees of dose-dependent lesions. The results indicated that cadmium can cause cell damages to the kidney, in particular to the mitochondria. Mitochondria can be used as one biomarker in the monitoring of cadmium pollution and its quantitative risk assessments.

Plants buffer some of the effects of a pair of cadmium-exposed zebrafish on the un-exposed majority

Certain individuals have a disproportionate effect on group responses. Characteristics may include susceptibility to pollutants, such as cadmium (Cd), a potent trace metal. Here, we show how a pair of Cd-exposed individuals can impact the behavior of unexposed groups. We used behavioral assessments to characterize the extent of the effects of the Cd-exposed individuals on group boldness, cohesion, foraging, activity, and responses to plants. We found that groups with a pair of Cd-exposed fish remained closer to novel stimuli and plants than did groups with untreated (control) fish. The presence of plants reduced Cd-induced differences in shoal cohesion and delays feeding in male shoals. Shoals with Cd- and water-treated fish were equally active. The results suggest that fish acutely exposed to environmentally relevant Cd concentrations can have profound effects on the un-exposed majority. However, the presence of plants may mitigate the effects of contaminants on some aspects of social behavior.

Cadmium in topsoils of the European Union - An analysis based on LUCAS topsoil database

Cadmium (Cd) is a naturally occurring element that can accumulate in the soil through the application of fertilisers containing cadmium and as a waste of industrial processes. Cadmium inputs in the soil have increased significantly (+50 %) during the 20th century as a result of the application of fertilisers and sewage sludge, and also due to local contamination (e.g. waste dumping, mining) and industrial emissions (e.g. zinc smelters). Using the 21,682 soil samples from the LUCAS soil survey, we aim to estimate the spatial distribution of the concentration of Cd in the European Union (EU) and UK topsoil. Out of the total, 72.6 % of the samples have Cd values <0.07 mg kg-1, 21.6 % in the range 0.07-1 mg kg-1 and the remaining 5.5 % higher than the threshold of 1 mg kg-1, which is generally considered the limit for risk assessment. The mean Cd value in the EU topsoils is 0.20 mg kg-1, slightly higher in grasslands (0.24 mg kg-1) compared to croplands (0.17 mg kg-1). Applying an ensemble of machine learning models supported by a variety of environmental descriptors, we created maps of Cd distribution at a resolution of 100 m. The ensemble approach included five models and increased the prediction accuracy to R2 of 0.45 (an increase of 0.1 compared to best single model performance). The approach used resulted in a high predictive power for the general Cd distribution, while also identifying hotspots of Cd contamination. Natural factors influencing Cd levels include soil properties (pH, clay), topography, soil erosion, and leaching. As anthropogenic factors, we identified phosphorus inputs to agricultural lands as the most important for Cd levels. The application of the EU Fertiliser Directive should further limit Cd inputs and potentially the Cd content in soils.

Behavioural ecology meets oncology: quantifying the recovery of animal behaviour to a transient exposure to a cancer risk factor

Wildlife is increasingly exposed to sublethal transient cancer risk factors, including mutagenic substances, which activates their anti-cancer defences, promotes tumourigenesis, and may negatively impact populations. Little is known about how exposure to cancer risk factors impacts the behaviour of wildlife. Here, we investigated the effects of a sublethal, short-term exposure to a carcinogen at environmentally relevant concentrations on the activity patterns of wild Girardia tigrina planaria during a two-phase experiment, consisting of a 7-day exposure to cadmium period followed by a 7-day recovery period. To comprehensively explore the effects of the exposure on activity patterns, we employed the double hierarchical generalized linear model framework which explicitly models residual intraindividual variability in addition to the mean and variance of the population. We found that exposed planaria were less active compared to unexposed individuals and were able to recover to pre-exposure activity levels albeit with a reduced variance in activity at the start of the recovery phase. Planaria showing high activity levels were less predictable with larger daily activity variations and higher residual variance. Thus, the shift in behavioural variability induced by an exposure to a cancer risk factor can be quantified using advanced tools from the field of behavioural ecology. This is required to understand how tumourous processes affect the ecology of species.

Metals and arsenic distribution in stray dogs' tissues around a lead-zinc mine in Kabwe, Zambia

Metal contamination poses a threat to human, animal, and environmental health. The purpose of the current study was to assess the accumulation of toxic and trace metal concentrations in tissues of stray dogs in Kabwe, a town known for lead pollution due to a long history of lead and zinc mining. Brain, spleen, heart, stomach, stomach content, small intestine, kidney, liver, and bone samples were collected from 29 stray dogs (14 from locations within 3 km of the mine and 15 from sites 7 km away from the mine) after necropsy. Inductively coupled plasma mass spectrometry was used to analyze toxic metals, arsenic (As), cadmium (Cd), and lead (Pb), and trace elements, copper (Cu) and zinc (Zn). The lungs (0.117 ± 0.114 mg/kg dry weight), kidney (7.515 ± 8.830 mg/kg dry weight), and bone (41.68 ± 66.83 mg/kg dry weight) were found to have the highest concentrations of As, Cd, and Pb, respectively. In contrast, higher Cu and Zn concentrations were measured in the liver than in other tissues. In all tissues analyzed, tissues sampled from dogs near the mine had significantly higher mean concentrations of Cd and Pb than dogs far away. Neither sex nor age-related differences were observed in the distribution of metals in most tissues. There were significant associations among toxic (Pb and Cd) and trace metals (Cu and Zn). In the kidney, Cd positively correlated with Pb (ρ = 0.534) and Zn (ρ = 0.600), whereas in the liver, Cu correlated with Zn (ρ = 0.565). The current study's findings suggest that environmental pollution is still a problem in Kabwe, and environmental remediation is needed to address the pollution.

Protein S-palmitoylation enhances profibrotic signaling in response to cadmium

Cadmium (Cd) is a naturally occurring, toxic environmental metal found in foods. Humans do not have an efficient mechanism for Cd elimination; thus, Cd burden in humans increases with age. Cell and mouse studies show that Cd burden from low environmental levels of exposure impacts lung cell metabolism, proliferation signaling and cell growth as part of disease-promoting profibrotic responses in the lungs. Prior integrative analysis of metabolomics and transcriptomics identified the zDHHC11 transcript as a central functional hub in response to Cd dose. zDHHC11 encodes a protein S-palmitoyltransferase, but no evidence is available for effects of Cd on protein S-palmitoylation. In the present research, we studied palmitoylation changes in response to Cd and found increased protein S-palmitoylation in human lung fibroblasts that was inhibited by 2-bromopalmitate (2-BP), an irreversible palmitoyltransferase inhibitor. Mass spectrometry-based proteomics showed palmitoylation of proteins involved in divalent metal transport and in fibrotic signaling. Mechanistic studies showed that 2-BP inhibited palmitoylation of divalent metal ion transporter ZIP14 and also inhibited cellular Cd uptake. Transcription analyses showed that Cd stimulated transforming growth factor (TGF)-β1 and β3 expression within 8 h and lung fibrotic markers α-smooth muscle actin, matrix metalloproteinase-2, and collagen 1α1 gene expression and that these effects were blocked by 2-BP. Because 2-BP also blocked palmitoylation of proteins controlled by TGFβ1, these results show that palmitoylation impacts Cd-dependent fibrotic signaling both by enhancing cellular Cd accumulation and by supporting post-translational processing of TGFβ1-dependent proteins.

Cadmium in Selected Organs of Game Animals from Areas with Different Degrees of Industrialisation and Its Intake by Human Consumers

The aim of this study was to determine the concentration of cadmium (Cd) in the organs of game animals from areas with different degrees of industrialisation and to assess its intake following the consumption of the livers of these animals. The material for this study consisted of liver and kidney samples taken from roe deer (Capreolus capreolus), red deer (Cervus elaphus), and wild boar (Sus scrofa) from five regions differing in land use and industrialisation. Compared to the kidneys, the liver was an indicator of the current state of the environment and Cd intake, while the kidney was used to assess the long-term accumulation of Cd in the body. The cadmium concentration in the samples was determined by inductively coupled plasma atomic emission spectrometry. The cadmium concentrations of the organs were found to vary according to geographical location, with the highest levels being observed in Southern Poland, i.e., areas characterised by the highest degree of industrialisation and the presence of heavy industry. However, high Cd concentrations were also reported in the northeastern region. Examples of excessive cadmium levels in the kidneys were noted in all tested regions. Cd intake by humans was evaluated by calculating the estimated daily cadmium intake, and this was compared with the tolerable weekly intake (TWI). The TWI was only exceeded by children frequently consuming wild boar liver from the southwest region.

Epigenetic control of the imprinted growth regulator Cdkn1c in cadmium-induced placental dysfunction

Cadmium (Cd) is a toxic metal ubiquitous in the environment. In utero, Cd is inefficiently transported to the foetus but causes foetal growth restriction (FGR), likely through impairment of the placenta where Cd accumulates. However, the underlying molecular mechanisms are poorly understood. Cd can modulate the expression of imprinted genes, defined by their transcription from one parental allele, which play critical roles in placental and foetal growth. The expression of imprinted genes is governed by DNA methylation at Imprinting Control Regions (ICRs), which are susceptible to environmental perturbation. The imprinted gene Cdkn1c/CDKN1C is a major regulator of placental development, is implicated in FGR, and shows increased expression in response to Cd exposure in mice. Here, we use a hybrid mouse model of in utero Cd exposure to determine if the increase in placental Cdkn1c expression is caused by changes to ICR DNA methylation and loss of imprinting (LOI). Consistent with prior studies, Cd causes FGR and impacts placental structure and Cdkn1c expression at late gestation. Using polymorphisms to distinguish parental alleles, we demonstrate that increased Cdkn1c expression is not driven by changes to DNA methylation or LOI. We show that Cdkn1c is expressed primarily in the placental labyrinth which is proportionally increased in size in response to Cd. We conclude that the Cd-associated increase in Cdkn1c expression can be fully explained by alterations to placental structure. These results have implications for understanding mechanisms of Cd-induced placental dysfunction and, more broadly, for the study of FGR associated with increased Cdkn1c/CDKN1C expression.

In vitro cadmium exposure induces structural damage and endothelial dysfunction in female rat aorta

Cadmium is a heavy metal that is widespread in the environment and has been described as a metalloestrogen and a cardiovascular risk factor. Experimental studies conducted in male animals have shown that cadmium exposure induces vascular dysfunction, which could lead to vasculopathies caused by this metal. However, it is necessary to investigate the vascular effects of cadmium in female rats to understand its potential sex-dependent impact on the cardiovascular system. While its effects on male rats have been studied, cadmium may act differently in females due to its potential as a metalloestrogen. In vitro studies conducted in a controlled environment allow for a direct assessment of cadmium's impact on vascular function, and the use of female rats ensures that sex-dependent effects are evaluated. Therefore, the aim of this study was to investigate the in vitro effects of Cadmium Chloride (CdCl2, 5 µM) exposure on vascular reactivity in the isolated aorta of female Wistar rats. Exposure to CdCl2 damaged the architecture of the vascular endothelium. CdCl2 incubation increased the production and release of O2•-, reduced the participation of potassium (K+) channels, and increased the participation of the angiotensin II pathway in response to phenylephrine. Moreover, estrogen receptors alpha (Erα) modulated vascular reactivity to phenylephrine in the presence of cadmium, supporting the hypothesis that cadmium could act as a metalloestrogen. Our results demonstrated that in vitro cadmium exposure induces damage to endothelial architecture and an increase in oxidative stress in the isolated aorta of female rats, which could precipitate vasculopathies. Graphical Abstract. Own source from Canva and Servier Medical Art servers.

A Pair of Cadmium-exposed Zebrafish Affect Boldness and Landmark use in the Un-exposed Majority

Some individuals have a disproportionate effect on group responses. These individuals may possess distinct attributes that differentiate them from others. These characteristics may include susceptibility to contaminant exposure such as cadmium, a potent trace metal present in water and food. Here, we tested whether a pair of cadmium-exposed individuals could exert an impact on the behavior of the unexposed majority. We used behavioral assessments to characterize the extent of the effects of the cadmium-exposed pair on group boldness, cohesion, activity and responses to landmarks. We found that groups with a pair of cadmium-exposed fish approached and remained closer to novel stimuli and landmarks than did groups with pairs of fish treated with uncontaminated water (control). Shoals with cadmium and water treated fish exhibited similar levels of cohesion and activity. The results suggest that fish acutely exposed to environmentally-relevant cadmium concentrations can have profound effects on the un-exposed majority.

Concentration of Potentially Toxic Elements in Farmed Fallow Deer Antlers Depending on Diet and Age

Deer antlers, usually harvested annually on a farm, are an accessible material used to determine the exposition to potentially toxic elements, PTEs, during growth. Moreover, the study of antlers from animals of different ages allows the assessment of long-term exposition to these elements. The aim of the study was to analyze the concentration of eight potentially toxic elements (Cd, Pb, As, Ba, Ni, Sr, La, Ce) in individual positions of the antlers (first, second, and third position, corresponding to the stages of development and life of these animals) and in the food that the animals consumed during the growth of individual antler fragments, depending on the age of the farmed fallow deer (Dama dama). The mineral composition of samples was analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The analysis included 31 male deer aged 2-8 years old. The average concentration of Pb, Ba, and Ni was higher in the second position of the antler, and As, La, and Ce in the third position. In addition, the oldest individuals showed a higher Cd, Pb, and As concentration in the third position. A significant positive relationship was found between the age of animals and accumulation of As (r = 0.582, p < 0.05), as well as Ba and Sr (r = -0.534, r = -0.644 at p < 0.05, respectively). The average content of Ba and Sr also significantly negatively depended on body mass and antler mass stags (r = -0.436, r = -0.515 at p < 0.05, respectively). Cd concentration in feed was significantly higher in June compared to winter, spring, and later summer (p < 0.05). On the other hand, the concentration of Ba in food was significantly higher in spring and winter than in early and later summer (p < 0.05). An increase in the PTEs in the pasture determined the concentration of these components in fallow deer antlers.

Simultaneous detection of mercury and cadmium ions: A colorimetric method in aqueous media

Hg and Cd are the two most toxic heavy metal ions that could be found in aqueous solutions. In this study, a chemosensor based on 5-(4-((4-nitrophenyl) diazenyl) phenyl)-1,3,4-oxadiazole-2-thiol (DOT) was reported to detect these ions simultaneously. DOT showed high selectivity towards Hg ion by changing the color of the solution from beige to gold-yellow at different concentrations of Hg ion. In comparison, other relevant metals, such as Li+, Na+, K+, Cs+, Mg2+, Ca2+, Al3+, Fe2+, Ag+, Cu2+, Pb2+, Ni2+, Zn2+, Cr3+, Fe3+, Pb4+, Mn2+, and Cd2+ did not affect the color of the DOT solution as the interfering ions. Despite no changes in the color of DOT solution in the presence of Cd ion, a solution containing DOT-Hg complex was changed from gold-yellow to orange by adding Cd ion, providing an approach for detecting Hg and Cd ion simultaneously with UV-Vis and Fluorescent spectroscopy. DOT exhibited a high association constant with a detection limit of 0.05 μM for Hg and Cd ions in an aqueous solution. The results of quantum mechanics (QM) calculations were also consistent with the experimental observations, which indicated that changes in the band gap could explain the various colors of DOT complex with metal ions.

Contaminant Metals and Cardiovascular Health

A growing body of research has begun to link exposure to environmental contaminants, such as heavy metals, with a variety of negative health outcomes. In this paper, we sought to review the current research describing the impact of certain common contaminant metals on cardiovascular (CV) health. We reviewed ten metals: lead, barium, nickel, chromium, cadmium, arsenic, mercury, selenium, zinc, and copper. After a literature review, we briefly summarized the routes of environmental exposure, pathophysiological mechanisms, CV health impacts, and exposure prevention and/or mitigation strategies for each metal. The resulting article discloses a broad spectrum of pathological significance, from relatively benign substances with little to no described effects on CV health, such as chromium and selenium, to substances with a wide-ranging and relatively severe spectrum of CV pathologies, such as arsenic, cadmium, and lead. It is our hope that this article will provide clinicians with a practical overview of the impact of these common environmental contaminants on CV health as well as highlight areas that require further investigation to better understand how these metals impact the incidence and progression of CV diseases.

Turn-on fluorogenic sensors based on an anthraquinone signaling unit for the detection of Zn(II) and Cd(II) ions

Turn-on fluorescent chemosensors based on an anthraquinone moiety, N,N'-(9,10-dioxo-9,10-dihydroanthracene-1,8-diyl)bis(2-(bis(pyridin-2-ylmethyl)amino)acetamide) (1) and N,N'-(9,10-dioxo-9,10-dihydroanthracene-2,6-diyl)bis(2-(bis(pyridin-2-ylmethyl)amino)acetamide) (2), have been successfully synthesized with the overall yields of 61% and 90%, respectively. The structures of both chemosensors 1 and 2 were elucidated using several spectroscopic techniques such as 1H NMR, 13C NMR, 2D-NMR, FTIR and HRMS. The target chemosensor 1 is a promising tool for the detection of trace levels of d10 metal ions, such as Zn(II) and Cd(II) ions, by exhibiting a significant fluorescence enhancement via a turn-on photoinduced electron transfer (PET) mechanism with a rapid and highly reproducible signal, and low detection limit values of 0.408 μM and 0.246 μM, for Zn(II) and Cd(II), respectively.

Cadmium Exposure in Aquatic Products and Health Risk Classification Assessment in Residents of Zhejiang, China

Cadmium (Cd) pollution of food safety is a prominent food safety concern worldwide. The concentration of Cd in six aquatic food categories collected from 2018 to 2022 was analyzed using inductively coupled plasma mass spectrometry, and the Cd exposure levels were calculated by combining the Cd concentration and food consumption data of 18913 urban and rural residents in Zhejiang Province in 2015-2016. The mean Cd concentration was 0.699 mg/kg and the mean Cd exposure of aquatic foods was 0.00951 mg/kg BW/month for the general population. Marine crustaceans were the largest Cd contributor, corresponding to 82.7%. The regional distribution results showed that the average Cd exposure levels of 11 cities did not exceed the provisional tolerable monthly intake (PTMI). According to the subgroups, the Cd mean exposure level of 2-3-year-old children was significantly higher than that of the other age groups but did not exceed the PTMI. Health risk classification assessment demonstrated that the final risk score was six, and the health risk level of Cd exposure in aquatic products in the Zhejiang population was medium. These results demonstrated that the risk of Cd exposure in certain food types or age groups should be given more concern.

Reduction of bioavailability and phytotoxicity effect of cadmium in soil by microbial-induced carbonate precipitation using metabolites of ureolytic bacterium Ochrobactrum sp. POC9

The application of ureolytic bacteria for bioremediation of soil contaminated with heavy metals, including cadmium (Cd), allows for the efficient immobilization of heavy metals by precipitation or coprecipitation with carbonates. Microbially-induced carbonate precipitation process may be useful also in the case of the cultivation of crop plants in various agricultural soils with trace but legally permissible Cd concentrations, which may be still uptaken by plants. This study aimed to investigate the influence of soil supplementation with metabolites containing carbonates (MCC) produced by the ureolytic bacterium Ochrobactrum sp. POC9 on the Cd mobility in the soil as well as on the Cd uptake efficiency and general condition of crop plants (Petroselinum crispum). In the frame of the conducted studies (i) carbonate productivity of the POC9 strain, (ii) the efficiency of Cd immobilization in soil supplemented with MCC, (iii) crystallization of cadmium carbonate in the soil enriched with MCC, (iv) the effect of MCC on the physico-chemical and microbiological properties of soil, and (v) the effect of changes in soil properties on the morphology, growth rate, and Cd-uptake efficiency of crop plants were investigated. The experiments were conducted in soil contaminated with a low concentration of Cd to simulate the natural environmental conditions. Soil supplementation with MCC significantly reduced the bioavailability of Cd in soil with regard to control variants by about 27-65% (depending on the volume of MCC) and reduced the Cd uptake by plants by about 86% and 74% in shoots and roots, respectively. Furthermore, due to the decrease in soil toxicity and improvement of soil nutrition with other metabolites produced during the urea degradation (MCC), some microbiological properties of soil (quantity and activity of soil microorganisms), as well as the general condition of plants, were also significantly improved. Soil supplementation with MCC enabled efficient Cd stabilization and significantly reduced its toxicity for soil microbiota and plants. Thus, MCC produced by POC9 strain may be used not only as an effective Cd immobilizer in soil but also as a microbe and plant stimulators.

Alpha-ketoglutarate alleviates cadmium-induced inflammation by inhibiting the HIF1A-TNFAIP3 pathway in hepatocytes

The threat to public health posed by rapidly increasing levels of cadmium (Cd) in the environment is receiving worldwide attention. Although, Cd is known to be absorbed into the body and causes non-negligible damage to the liver, the detailed mechanisms underlying its hepatoxicity are incompletely understood. In the present study, investigated the effect of TNFAIP3 and α-ketoglutarate (AKG) on Cd-induced liver inflammation and hepatocyte death. Male C57BL/6 mice were exposed to cadmium chloride (1.0 mg/kg) while being fed a diet with 2 % AKG for two weeks. We found that Cd induced hepatocyte injury and inflammatory infiltration. In addition, TNFAIP3 expression was inhibited in the liver tissues and cells of CdCl₂-treated mice. Mouse hepatocyte-specific TNFAIP3 overexpression by tail vein injection of an adeno-associated virus (AAV) vector effectively alleviated Cd-induced hepatic necrosis and inflammation, which was mediated by the NF-κB signaling pathway. Notably, this inhibitory effect of TNFAIP3 on Cd-induced liver injury was dependent on AKG. Exogenous addition of AKG prevented Cd exposure-induced increases in serum ALT, AST and LDH levels, production of pro-inflammatory cytokines, activation of the NF-κB signaling pathway, and even significantly reduced Cd-induced oxidative stress and hepatocyte death. Mechanistically, AKG exerted its anti-inflammatory effect by promoting the hydroxylation and degradation of HIF1A to reduce its Cd-induced overexpression in vivo and in vitro, avoiding the inhibition of the TNFAIP3 promoter by HIF1A. Moreover, the protective effect of AKG was significantly weaker in Cd-treated primary hepatocytes transfected with HIF1A pcDNA. Overall, our results reveal a novel mechanism of Cd-induced hepatotoxicity.

A biphenyl thiosemicarbazide based fluorogenic chemosensor for selective recognition of Cd2+: application in cell bioimaging

A diversified biphenyl thiosemicarbazide based chemosensor (HBMC) has been fabricated and reported for the specific detection of Cd2+ in a MeOH : H2O (4 : 1) solution. We observed a chromogenic change from colorless to light yellow colour, and it showed a "turn-on" fluorogenic change from non fluorescent to blooming cyan colour. In fluorometric titration a sharp "turn-on" emission for Cd2+ was observed with a ∼16 fold increase in fluorescence intensity value at 496 nm by incremental addition of Cd2+ ions in the MeOH : H2O (4 : 1) solution. The reversibility of the chemosensor (HBMC) was confirmed by a sequential addition of the EDTA solution. Again the binding stoichiometry of HBMC with Cd2+ was found to be 2 : 1, as confirmed by Job's plot analysis and HRMS spectra of the HBMC-Cd2+ complex. The mechanism for Cd2+ sensing in MeOH : H2O (4 : 1) is based upon the inhibition of CN isomerization and ESIPT process and simultaneously turning on the CHEF (chelation enhanced fluorescence) process. The limit of detection for Cd2+ was found to be in the order of 10-8 (M), which implies that HBMC is an efficient probe to detect Cd2+ at the microscopic level. A reusability study was performed and on-sight detection of cadmium ions by the chemosensor (HBMC) was established by dip-stick experiment. In vitro detection of Cd2+ in human breast cancer cells (MDA-MB-231) by HBMC discloses its cell permeability and biocompatible nature. Computational studies (DFT and TDDFT) with the probe HBMC and HBMC-Cd2+ complex were also performed.

A pair of cadmium-exposed zebrafish affect social behavior of the un-exposed majority

To account for global contamination events, we must identify direct and indirect pollutant effects. Although pollutants can have direct effects on individuals, it is unknown how a few contaminated individuals affect groups, a widespread social organization. We show environmentally relevant levels of cadmium (Cd) can have indirect social effects revealed in the social context of a larger group. Cd-contaminated individuals had poor vision and more aggressive responses, but no other behavioral effects. The presence of experienced Cd-exposed pairs in the groups had an indirect effect on the un-exposed individual's social interactions leading to the shoal becoming bolder and moving closer to a novel object than control groups. Because a few directly affected individuals could indirectly affect social behavior of the un-exposed majority, we believe that such acute but potentially important heavy metal toxicity could inform reliable predictions about the consequences of their use in a changing world.

Blood selenium level can alleviate the nephrotoxicity of lead and cadmium in the general population of the United States: a retrospective cross section analysis of population-based nationally representative data

The current understanding of the interplay between blood selenium, cadmium and lead levels, and chronic kidney disease (CKD) is limited. Our objective was to investigate whether elevated blood selenium levels can mitigate the nephrotoxic effects of lead and cadmium. The exposure variables examined in this study include blood selenium, cadmium, and lead levels measured by ICP-MS. The outcome of interest was CKD, defined as an estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73 m². In total, 10630 participants (mean (SD) age:48.9 ± 18.4; 48.3% male) were included in this analysis. The median (IQR) of blood selenium, cadmium, and lead levels was 191 (177-207) μg/L, 0.300 (0.180-0.540) μg/L, and 0.940 (0.570-1.510) μg/dL, respectively. We observed a significant positive association between cadmium and lead levels and CKD (OR; 1.86; 95%CI: 1.31- 2.64; OR:2.23; 95%CI:1.54-3.24). However, selenium had a negative association with CKD (OR:0.096; 95%CI:0.020-0.457). Based on a reference group with a selenium concentration of ≤ 191 μg/L and cadmium level of > 0.300 μg/L, a significant protective factor in the CKD was seen in subjects with high plasma selenium and lower cadmium concentrations (OR:0.685; 95%CI:0.515-0.912). Then selenium concentration of ≤ 191 μg/L and lead level of > 0.940 μg/dL were set as a reference group, and the OR for CKD decreased among the other group (OR:0.564; 95%CI;0.417- 0.762). The subgroup analysis indicated that there were no effect modifiers. Blood selenium has the potential to mitigate the nephrotoxic effects of lead and cadmium in the general population of the United States.

Reducing cadmium accumulation in shrimp using Escherichia coli with surface-displayed peptide

Cadmium (Cd) is a hazardous metal that can accumulate in aquatic organisms and endanger human health via the food chain. In this study, genetic engineering was used to display a peptide with Cd-binding potential on the surface of Escherichia coli cells. This whole-cell adsorbent exhibited high affinity for Cd ions (Cd²⁺) in the solution. The Cd²⁺ adsorption capacity of the whole-cell adsorbent was three-fold that of the control cells in a 20 μM Cd²⁺ solution, and 97.2% ± 2.38% of the Cd²⁺ was removed. The whole-cell adsorbent was fed to shrimp (Neocaridina denticulata), and the surface-engineered E. coli successfully colonized the shrimp intestine, which showed significantly less Cd accumulation than the group not fed surface-engineered E. coli. The whole-cell adsorbent evidently protected shrimp from the toxicity of Cd²⁺ by adsorbing it. Moreover, the whole-cell adsorbent mitigated the changes in microbial community structure in the shrimp gut caused by the exposure of Cd²⁺. These findings suggest that this strategy is effective for controlling the contamination of Cd²⁺ in shrimp.

Associations of micronutrients exposure with cadmium body burden among population: A systematic review

BACKGROUND

The absorption and accumulation of cadmium (Cd) within the human body can be influenced by the status of certain micronutrients, while available evidence for the association between micronutrient exposure and Cd body burden remains fragmented and inconsistent. To address this issue, this article reviews and synthesizes epidemiological studies that examine the association between micronutrient exposure and Cd burden in humans, to elucidate the potential association between micronutrient exposure and Cd body burden.

METHODS

We conducted a systematic review of epidemiologic studies reporting the association between micronutrient status and Cd body burden among the population. Relevant articles were selected based on predetermined criteria from PubMed, Web of Science, and Scopus databases published from 2000 to 2021. The exposures that were evaluated included micronutrients (zinc, selenium, iron, calcium, and vitamins) status or intakes of them. The outcome of interest was the Cd body burden as indicated by blood Cd or urinary Cd levels. The quality of included studies was assessed using The Joanna Briggs Institute critical appraisal tool. We extracted data from each article, including study design, study site, study population, micronutrient status, Cd body burden, and the correlations between micronutrient status and Cd body burden.

RESULTS

Our systematic search yielded 1660 articles. Of these, forty-four were selected for inclusion based on prespecified criteria. These selected articles evaluated the relationship between Cd body burden and seven different micronutrients, namely, selenium (Se), zinc (Zn), calcium (Ca), iron (Fe), vitamin A, vitamin B12, and vitamin D. The majority of studies (n = 41) were observational, while only three were randomized controlled trials. Among the seventeen studies assessing Zn status, ten reported a negative association between serum Zn levels or intake and urinary and blood Cd levels. Results were inconsistent among the ten studies examining the association between Se levels and Cd body burden. Six studies showed that Cd in blood and urine was negatively correlated with serum ferritin (SF), a biomarker of body Fe status. Two studies reported a negative correlation between Ca and blood Cd.

CONCLUSIONS

This synthesis of available evidence suggests that certain micronutrients, especially Zn and Fe, may play a role in reducing the Cd body burden among populations. The evidence strongly supports a negative association between Zn, Fe, and Cd body burden, whereas evidence for Se, Ca and vitamins is insufficient to draw definitive conclusions regarding their relationship with Cd body burden. In addition, observational studies limit the ability to infer a causal relationship between micronutrients and Cd body burden, highlighting the need for additional intervention studies. Our review may inform nutrient supplementation guidance, control of Cd body burden, and future research to mitigate the adverse health effects of Cd in the context of global Cd pollution.

The relationship between co-exposure to multiple heavy metals and liver damage

BACKGROUND

The impact of heavy metal exposure on human health has attracted widespread attention of researchers, and the impact of heavy metal exposure on liver function has also been confirmed, however, more attention is paid to the impact of single or two heavy metal exposures, and most epidemiological studies focus on heavy metal pollution areas. In this study, rural residents in non-heavy metal-contaminated areas in Northwest China were selected as the research objects to explore the comprehensive effects of co-exposure to multiple heavy metals on the liver, which can provide certain reference and support for related research.

OBJECTIVES

This study used a Bayesian nuclear machine model (BKMR) to evaluate the relationship between exposure to heavy metal mixtures and indicators of liver function in a population in rural Northwest China.

RESULTS

Exposure to higher concentrations of metal mixtures was positively correlated with total bilirubin, direct bilirubin, and aspartate aminotransferase, and negatively correlated with alanine aminotransferase, with Pb contributing the most to indicators of liver function. We also observed a possible interaction of Cd with other heavy metals in the effect of heavy metal mixtures on DB levels.

CONCLUSIONS

Concurrent exposure to higher concentrations of heavy metal mixtures (Cr, Co, Cd, and Pb) in rural China was associated with indicators representing poor liver function, of which the effect of lead on liver function should be focused. More prospective epidemiological studies and animal experiments need to be carried out to determine this relationship and possible mechanism.

An Electrochemical Sensor for the Determination of Trace Concentrations of Cadmium, Based on Spherical Glassy Carbon and Nanotubes

The practical application of a novel, eco-friendly electrochemical sensor based on low-dimensional structures, spherical glassy carbon microparticles, and multiwall carbon nanotubes is described. This sensor, modified with a bismuth film, was used for the determination of Cd(II) by the anodic stripping voltammetric method. The instrumental and chemical factors influencing the sensitivity of the procedure were thoroughly investigated and their most favorable values were selected (acetate buffer solution pH = 3 ± 0.1; 0.15 mmol L-1 Bi(III); activation potential/time: -2 V/3 s; accumulation potential/time: -0.9 V/50 s). Under the selected conditions, the method exhibited linearity in the range of 2 × 10-9 to 2 × 10-7 mol L-1 Cd(II) with a detection limit of 6.2 × 10-10 mol L-1 Cd(II). The results obtained also showed that the application of the sensor for Cd(II) detection did not experience any significant interference in the presence of a number of foreign ions. The applicability of this procedure was evaluated using TM-25.5 Environmental Matrix Reference Material and SPS-WW1 Waste Water Certified Reference Material as well as river water samples through addition and recovery tests.

Reactive Oxygen Species Control Osteoblast Apoptosis through SIRT1/PGC-1α/P53Lys382 Signaling, Mediating the Onset of Cd-Induced Osteoporosis

The imbalance between osteogenesis and osteoclastogenesis is a feature of bone metabolic disease. Cadmium (Cd) exposure causes human bone loss and osteoporosis (OP) through bioaccumulation of the food chain. However, the impact of Cd on bone tissues and the underlying molecular mechanisms are not well-characterized. In the current study, we found that the Cd concentration in bone tissues of OP patients was higher than normal subjects; meanwhile, the nuclear silent information regulator of transcription 1 (SIRT1) protein expression level was significantly decreased, which is a new star molecule to treat OP. It is further revealed that SIRT1 activation markedly reprograms bone metabolic and stress-response pathways that incline with osteoblast (OB) apoptosis. Suppressing reactive oxygen species (ROS) release with N-acetyl-l-cysteine (NAC) abolished Cd-induced reduction of SIRT1 protein, deacetylation of P53, OB apoptosis, and attenuated OP. Conversely, overexpression of SIRT1 suppressed Cd-induced ROS release. SIRT1 overexpression in vivo and in vitro dampened PGC-1α protein, acetylation of P53 at lysine 382, and caspase-dependent apoptosis. These results reveal that ROS/SIRT1 controls P53 acetylation and coordinates OB apoptosis involved in the onset of OP.

Arsenic, cadmium, and lead in rice and rice products on the Austrian market

Fifty-one rice samples, i.e. 25 rice varieties, 8 rice products, and 18 rice containing baby foods from the Austrian market were surveyed for arsenic, cadmium, and lead. Inorganic arsenic (iAs) is most toxic to human health, and its mean concentrations in rice were 120 µg kg^-1, 191 µg kg^-1 in rice products, and 77 µg kg^-1 in baby foods. The average dimethylarsinic acid and methylarsonic acid concentrations were 56 µg kg^-1 and 2 µg kg^-1, respectively. The highest iAs concentration was found in rice flakes (237 ± 15 µg kg^-1), close to the Maximum Level (ML) set by the EU regulation for husked rice (250 µg kg^-1). The levels of cadmium (12 to 182 µg kg^-1) and lead (6 to 30 µg kg^-1) in the majority of rice samples were below the European ML. Upland grown rice from Austria showed both, low inorganic arsenic (<19 µg kg^-1) and cadmium (<38 µg kg^-1) concentrations.

Crosstalk between Mfn2-mediated mitochondria associated membranes disorder and autophagy induced by molybdenum and cadmium in sheep heart

To investigate the crosstalk of mitochondria associated membranes (MAMs) disorder and autophagy co-induced by molybdenum (Mo) and cadmium (Cd) in sheep hearts. A total of 48 sheep were randomly divided into 4 groups: control group, Mo group, Cd group and Mo + Cd group. The intragastric administration lasted for 50 days. The results showed that Mo or/and Cd exposure could cause morphological damage, imbalance of trace elements and antioxidant function, Ca²⁺ concentration decreased markedly, and significantly increase the contents of Mo or/and Cd in myocardium. Additionally, the mRNA and protein levels of endoplasmic reticulum stress (ERS) related factors and mitochondrial biogenesis related factors were altered by Mo or/and Cd, as well as the content of ATP, inducing ERS and mitochondrial dysfunction. Meanwhile, Mo or/and Cd could lead to the alteration of expression level of MAMs-related genes and proteins, and the distance between mitochondria and endoplasmic reticulum (ER), resulting in MAMs disorder. Moreover, Mo or/and Cd exposure upregulated the mRNA and protein levels of autophagy related factors. In conclusion, our results revealed that Mo or/and Cd exposure caused ERS, mitochondrial dysfunction and structural MAMs disruption, ultimately leading to autophagy in sheep hearts, and the effects of Mo and Cd co-exposure were more obvious.

Auxin alleviates cadmium toxicity by increasing vacuolar compartmentalization and decreasing long-distance translocation of cadmium in Poa pratensis

Kentucky bluegrass (Poa pratensis L.) hyperaccumulates cadmium (Cd) and exhibits a hypertolerance. Thus, it has potential for the phytoremediation of Cd-containing soil. Auxin signaling is involved in the response to Cd stress. However, the mechanisms of auxin-mediated detoxification and Cd translocation in plants remain unclear. This study aimed to investigate the effects of exogenous application of indole-3-acetic acid (IAA) on the Cd translocation, subcellular Cd distribution, chemical forms of Cd, and transcriptional regulation of Kentucky bluegrass. The results showed that the exogenous application of IAA increased the amount of organelle-bound Cd and vacuole-compartmentalized Cd in root cells, reduced the Cd concentration in the leaf tissues (epidermis, mesophyll, and vascular bundle) and root tissues (rhizodermis and cortex) but increased in the stele, and alleviate Cd-induced leaf chlorosis and growth inhibition. The expression of genes associated with Cd transporters (ABCs, ZIPs, NASs, OPTs, and YSLs), phosphatases, oxalate decarboxylases and lignin biosynthesis were significantly regulated by exogenous IAA under Cd stress. A positive regulation of phosphatases and oxalate decarboxylases genes related to an increase in phosphate- and oxalate-bound Cd, as well as a decrease in pectate- and protein-bound Cd and inorganic Cd, thereby contributing to a decrease in Cd phytotoxicity. The significant regulation of Cd transporters associated with decreasing the long-distance translocation of Cd, and the activation of lignin biosynthesis may contribute to the development of root endodermal barriers and increase the deposition of undissolved Cd phosphates and oxalate-bound Cd in the stele. These results revealed the important role of auxin in Cd detoxification and translocation in Kentucky bluegrass and they provide a theoretical basis for the phytoremediation of Cd-containing soil.

Simultaneous determination of heavy metal concentrations and toxicities by diffusive gradient in thin films containing Acinetobacter whole-cell bioreporters (Bio-DGT)

Heavy metal contaminations may cause severe toxic impacts to ecological systems and human health. Measurements of metals' bioavailable concentrations and toxicities simultaneously and in-situ in environments can advance the understanding of their hazardous effects. The diffusive gradients in thin-films (DGT) is an in-situ technique can measure metal speciation and labile concentrations, but cannot yet provide the direct toxicity information. The whole-cell bioreporter Acinetobacter baylyi ADPWH_recA was successfully incorporated into the DGT device to develop a novel technique, Bio-DGT, for assessing the toxicity of metals at the same time of measuring their labile concentrations. The bioassay used in Bio-DGT can sense the mixture toxicity from multiple contaminants and the DGT can assist in identifying which toxicants may be causing the toxicity. Cadmium was used as the model metal to test the performance of Bio-DGT in waters and soils. The masses of Cd accumulated in Bio-DGT increased linearly and theoretically with time for 7 days deployment, indicating little influences from bioreporter cells on DGT performance. A positive relationship between bioluminescent signals towards Cd demonstrated the sensitive and active bioreporters' response. The sensitive of Bio-DGT, indicated by Cd concentrations causing the response, is 0.01 mg/L. The stable response from Bio-DGT under various conditions (pH 4-8, ionic strengths 0.01-0.5 M) and 30 days storage time suggest the applicability of the technique in real environments. The deployment of Bio-DGT in contaminated soils demonstrated that Cd toxicity was regulated by labile concentration, showing its potential application for the risk assessment of heavy metal contaminations, and its further feasibility in using Bio-DGT for measuring integration of multiple contaminants' effects and simultaneously determine the main toxicity driver(s).

MCU Upregulation Overactivates Mitophagy by Promoting VDAC1 Dimerization and Ubiquitination in the Hepatotoxicity of Cadmium

Cadmium (Cd) is a high-risk pathogenic toxin for hepatic diseases. Excessive mitophagy is a hallmark in Cd-induced hepatotoxicity. However, the underlying mechanism remains obscure. Mitochondrial calcium uniporter (MCU) is a key regulator for mitochondrial and cellular homeostasis. Here, Cd exposure upregulated MCU expression and increased mitochondrial Ca2+ uptake are found. MCU inhibition through siRNA or by Ru360 significantly attenuates Cd-induced excessive mitophagy, thereby rescues mitochondrial dysfunction and increases hepatocyte viability. Heterozygous MCU knockout mice exhibit improved liver function, ameliorated pathological damage, less mitochondrial fragmentation, and mitophagy after Cd exposure. Mechanistically, Cd upregulates MCU expression through phosphorylation activation of cAMP-response element binding protein at Ser133(CREBS133 ) and subsequent binding of MCU promoter at the TGAGGTCT, ACGTCA, and CTCCGTGATGTA regions, leading to increased MCU gene transcription. The upregulated MCU intensively interacts with voltage-dependent anion-selective channel protein 1 (VDAC1), enhances its dimerization and ubiquitination, resulting in excessive mitophagy. This study reveals a novel mechanism, through which Cd upregulates MCU to enhance mitophagy and hepatotoxicity.

Relative Bioavailability of Cadmium in Rice: Assessment, Modeling, and Application for Risk Assessment

Rice consumption is the primary route of cadmium (Cd) exposure to the populations with rice as the staple food. To accurately assess the potential health risks of Cd exposure via rice consumption, determination of Cd relative bioavailability (RBA) in rice is necessary. However, large variations exist in Cd-RBA, hindering the application of source-specific Cd-RBA values to different rice samples. In this study, we collected 14 rice samples from Cd contaminated areas and determined both rice compositions and Cd-RBA using in vivo mouse bioassay. Total Cd concentration varied from 0.19 to 2.54 mg/kg in the 14 rice samples, while Cd-RBA in rice ranged from 42.10% to 76.29%. Cadmium-RBA in rice correlated positively with calcium (Ca) (R = 0.76) and amylose content (R = 0.75) but negatively with the concentrations of sulfur (R = -0.85), phosphorus (R = -0.73), phytic acid (R = -0.68), and crude protein (R = -0.53). Cd-RBA in rice can be predicted by Ca and phytic acid concentrations in a regression model (R² = 0.80). Based on the total and bioavailable Cd concentrations in rice, weekly dietary Cd intake for adults was estimated to be 4.84-64.88 and 2.04-42.29 μg/kg bw/week, respectively. This work demonstrates the possibility of Cd-RBA prediction based on rice compositions and provides valuable suggestions for health risk assessment with consideration of Cd-RBA.

Effect of Cadmium on Oxidative Stress Indices and Vitamin D Concentrations in Children

Heavy metal poisoning can have serious health consequences, including damage to the brain, kidneys, and other organs. Cadmium is a toxic heavy metal that can accumulate in the body over time and the exposure to this element has been linked to a variety of adverse health effects. Cadmium toxicity can lead to an imbalance in the cellular redox state and be a source of oxidative stress. On the molecular level, cadmium ions negatively affect cellular metabolism, including the disruption of energy production, protein synthesis, and DNA damage. The study has been carried out on a group of 140 school-age children (8 to 14 years old) inhabiting the industrialized areas of Upper Silesia. The study population was divided into two sub-groups based on the median concentration of cadmium in blood (0.27 µg/L): Low-CdB and High-CdB. Measured traits comprised blood cadmium levels (CdB) as well as a blood count and selected oxidative stress markers. This research study aimed to demonstrate a correlation between the impact of exposure to elevated cadmium concentrations in a population of children and certain markers of oxidative stress, and 25-OH vitamin D3 concentration. A negative correlation has been found between cadmium concentration and 25-OH vitamin D3 level, protein sulfhydryl groups content in blood serum, glutathione reductase activity, and lipofuscin and malondialdehyde levels in erythrocytes. The concentration of 25-OH vitamin D₃ in the High-CdB group was decreased by 23%. The oxidative stress indices can be considered a valuable indicator of early Cd-toxicity effects to be included in the routinely-applied cadmium exposure monitoring parameters, allowing the evaluation of stress intensity to the cell metabolism.

A Benzothiadiazole-Based Self-Assembled Cage for Cadmium Detection

A turn-on fluorescent probe, cage 1, was efficiently self-assembled by condensing 4,4'-(benzothiadiazole-4,7-diyl)dibenzaldehyde and TREN in chloroform. The formation of cage 1 was characterized and confirmed by NMR spectroscopy, mass spectrometry, and theoretical calculations. The yield of cage 1 could be controlled by tuning the reaction conditions, such as the precursor concentration. Interestingly, the addition of 10 equiv of Cd²⁺ relative to cage 1 could increase the fluorescence almost seven-fold. ¹H NMR and fluorescence experiments indicating fluorescence enhancement may be caused by the decomposition of cage 1. Such a high selectivity toward Cd²⁺ implies that the cage could potentially be employed in cadmium detection.

Orally Administrated Lactiplantibacillus plantarum BGAN8-Derived EPS-AN8 Ameliorates Cd Hazards in Rats

Cadmium (Cd) is a highly toxic metal that is distributed worldwide. Exposure to it is correlated with a vast number of diseases and organism malfunctions. Exopolysaccharides (EPS) derived from Lactiplantibacillus plantarum BGAN8, EPS-AN8, previously showed great potential for the in vitro protection of intestinal cells from this metal. Here, we investigated the potential of food supplemented with EPS-AN8 to protect rats from the hazardous effects of Cd exposure. After thirty days of exposure to lower (5 ppm) and higher (50 ppm)-Cd doses, the administration of EPS-AN8 led to decreased Cd content in the kidneys, liver, and blood compared to only Cd-treated groups, whereas the fecal Cd content was strongly enriched. In addition, EPS-AN8 reversed Cd-provoked effects on the most significant parameters of oxidative stress (MDA, CAT, GST, and GSH) and inflammation (IL-1β, TNF-α, and IFN-γ) in the duodenum. Moreover, micrographs of the duodenum were in line with these findings. As the gut microbiota has an important role in maintaining homeostasis, we used 16S rRNA amplicon sequencing and investigated the effects of Cd and EPS-AN8 on one part of the microbiota presented in the duodenum. Although Cd decreased the growth of lactobacilli and mostly favored the blooming of opportunistic pathogen bacteria, parallel intake of EPS-AN8 reversed those changes. Therefore, our results imply that EPS-AN8 might be extremely noteworthy in combatting this toxic environmental pollutant.