Heavy Metals In Environment Research Articles

Spatial distribution prediction of soil heavy metals based on sparse sampling and multi-source environmental data

Predicting the precise spatial distribution of heavy metals in soil is crucial, especially in the fields of environmental management and remediation. However, achieving accurate spatial predictions of soil heavy metals becomes quite challenging when the number of soil sampling points is relatively limited. To address this challenge, this study proposes a hybrid approach, namely, Light Gradient Boosting Machine plus Ordinary Kriging (LGBK), for predicting the spatial distribution of soil heavy metals. A total of 137 soil samples were collected from the Shengli Coal-mine Base in Inner Mongolia, China, and their heavy metal concentrations were measured. Leveraging environmental covariates and soil heavy metal data, we constructed the predictive model. Experimental results demonstrate that, in comparison to traditional models, LGBK exhibits superior predictive performance. For copper (Cu), zinc (Zn), chromium (Cr), and arsenic (As), the coefficients of determination (R²) from the cross-validation results are 0.65, 0.52, 0.57, and 0.63, respectively. Moreover, the LGBK model excels in capturing intricate spatial features in heavy metal distribution. It accurately forecasts trends in heavy metal distribution that closely align with actual measurements. Environmental ImplicationThis study introduces a novel method, LGBK, for predicting the spatial distribution of soil heavy metals. This method yields higher-precision predictions even with a limited number of sampling points. Furthermore, the study analyzes the spatial distribution characteristics of Cu, Zn, Cr, and As in the grassland coal-mine base, along with the key environmental factors influencing their spatial distribution. This research holds significant importance for the environmental regulation and remediation of heavy metal pollution.

Study of heavy metal resistance genes in Escherichia coli isolates from a marine ecosystem with a history of environmental pollution (arsenic, cadmium, copper, and mercury).

We analyzed whole genome sequences of 308 Escherichia coli isolates from a marine ecosystem to determine the prevalence and relationships of heavy metal resistance genes (HMRGs) and antibiotic resistance genes (ARGs), as well as the presence of plasmid sequences. We screened all genomes for presence of 18 functional HMRGs conferring resistance to arsenic, cadmium, copper, or cadmium/mercury. In subset analyses, we examined geographic variations of HMRG carriage patterns in 224 isolates from water sources, and sought genetic linkages between HMRGs and ARGs in 25 genomes of isolates resistant to antibiotics. We found high carriage rates of HMRGs in all genomes, with 100% carrying at least one copy of 11 out of 18 HMRGs. A total of 173 (56%) of the isolates carried both HMRGs and plasmid sequences. In the 25 genomes of antibiotic-resistant isolates, 80% (n = 20) carried HMRGs, ARGs, and plasmid sequences, while 40% (n = 10) had linked HMRGs and ARGs on their assembled genomes. We found no evidence of geographic variation in HMRG frequency, nor any association between locational proximity to Superfund sites and co-carriage of HMRGs and ARGs. Our study findings indicate that HMRGs are common among E. coli in marine ecosystems, suggesting widespread heavy metal presence in water sources of a region with history of environmental pollution. Further research is needed to determine the role HMRGs play in driving antimicrobial resistance in human pathogens through genetic linkage and the value their detection in environmental bacterial genomes may offer as an indicator of environmental heavy metal pollution.

Chemical Composition of Salvia fruticosa Mill. Essential Oil and Its Protective Effects on Both Photosynthetic Damage and Oxidative Stress in Conocephalum conicum L. Induced by Environmental Heavy Metal Concentrations.

The genus Salvia L., belonging to the Lamiaceae family, contains more than 900 species distributed in various parts of the world. It is a genus containing aromatic plants used both in the culinary field and above all in the cosmetic area to produce several perfumes. Salvia fruticosa Mill., notoriously known as Greek Salvia, is a plant used since ancient times in traditional medicine, but today cultivated and used in various parts of Europe and Africa. Polar and apolar extracts of this plant confirmed the presence of several metabolites such as abietane and labdane diterpenoids, triterpenoids, steroids, and some flavonoids, causing interesting properties such as sedative, carminative, and antiseptic, while its essential oils (EOs) are mainly characterized by compounds such as 1,8-cineole and camphor. The aim of this work concerns the chemical analysis by GC and GC-MS, and the investigation of the biological properties, of the EO of S. fruticosa plants collected in eastern Sicily. The gas-chromatographic analysis confirmed the presence of 1,8-cineole (17.38%) and camphor (12.81%), but at the same time, also moderate amounts of α-terpineol (6.74%), β-myrcene (9.07%), camphene (8.66%), β-pinene (6.55%), and α-pinene (6.45%). To study the protective effect of EOs from S. fruticosa (both the total mixture and the individual compounds) on possible damage induced by heavy metals, an in vitro system was used in which a model organism, the liverwort Conocephalum conicum, was subjected to the effect of a mix of heavy metals (HM) prepared using values of concentrations actually measured in one of the most polluted watercourses of the Campania region, the Regi Lagni. Finally, the antioxidant response and the photosynthetic damage were examined. The exogenous application of the EO yields a resumption of the oxidative stress induced by HM, as demonstrated by the reduction in the Reactive Oxygen Species (ROS) content and by the increased activity of antioxidant enzyme catalase (CAT) and glutathione-S-transferase (GST). Furthermore, plants treated with HMs and EO showed a higher Fv/Fm (maximal quantum efficiency of PSII in the dark) with respect to HMs-only treated ones. These results clearly indicate the protective capacity of the EO of S. fruticosa against oxidative stress, which is achieved at least in part by modulating the redox state through the antioxidant pathway and on photosynthetic damage.

Bacterial heavy metal resistance related to environmental conditions

Contaminated water bodies such as rivers provide reservoirs for bacterial resistance. This field study tested the water quality and the bacterial resistance to heavy metals of Qishan River water pollution. Wastewater discharged to environmental surface waters is a major pathway of heavy metals and heavy metal-resistant bacteria. Contaminated water bodies such as rivers provide reservoirs for bacterial resistance. This field study tested the water quality and bacterial resistance to heavy metals of Qishan River water pollution. Guided by our research hypothesis that an overall increase in downstream heavy metal resistance levels was following an increase in human settlements were eight sites sampled along the Qishan River. These were situated upstream and downstream to the confluence of the Qishan River with the Kaoping River. In the laboratory bacterial heavy metal resistance was bio-assayed by disk diffusion and micro-dilution with six widely used heavy metals. The comparison of bacterial resistance was among Qishan River upstream sites (sites 1–6) and downstream sites (sites 7–9). Multi-drug-resistant bacteria and co-resistance against heavy metals and antibacterials appeared at site 8. This research discusses the correlation between environmental factors, and antibacterial and heavy metal resistance. The results provide stakeholders and authorities responsible for environmental pollution with a reference for risk assessment and management of bacterial resistance.

Electrochemical and Colorimetric Nanosensors for Detection of Heavy Metal Ions: A Review.

Human exposure to acute and chronic levels of heavy metal ions are linked with various health issues, including reduced children's intelligence quotients, developmental challenges, cancers, hypertension, immune system compromises, cytotoxicity, oxidative cellular damage, and neurological disorders, among other health challenges. The potential environmental HMI contaminations, the biomagnification of heavy metal ions along food chains, and the associated risk factors of heavy metal ions on public health safety are a global concern of top priority. Hence, developing low-cost analytical protocols capable of rapid, selective, sensitive, and accurate detection of heavy metal ions in environmental samples and consumable products is of global public health interest. Conventional flame atomic absorption spectroscopy, graphite furnace atomic absorption spectroscopy, atomic emission spectroscopy, inductively coupled plasma-optical emission spectroscopy, inductively coupled plasma-mass spectroscopy, X-ray diffractometry, and X-ray fluorescence have been well-developed for HMIs and trace element analysis with excellent but varying degrees of sensitivity, selectivity, and accuracy. In addition to high instrumental running and maintenance costs and specialized personnel training, these instruments are not portable, limiting their practicality for on-demand, in situ, field study, or point-of-need HMI detection. Increases in the use of electrochemical and colorimetric techniques for heavy metal ion detections arise because of portable instrumentation, high sensitivity and selectivity, cost-effectiveness, small size requirements, rapidity, and visual detection of colorimetric nanosensors that facilitate on-demand, in situ, and field heavy metal ion detections. This review highlights the new approach to low-cost, rapid, selective, sensitive, and accurate detection of heavy metal ions in ecosystems (soil, water, air) and consumable products. Specifically, the review highlights low-cost, portable, and recent advances in smartphone-operated screen-printed electrodes (SPEs), plastic chip SPES, and carbon fiber paper-based nanosensors for environmental heavy metal ion detection. In addition, the review highlights recent advances in colorimetric nanosensors for heavy metal ion detection requirements. The review provides the advantages of electrochemical and optical nanosensors over the conventional methods of HMI analyses. The review further provides in-depth coverage of the detection of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) ions in the ecosystem, with emphasis on environmental and biological samples. In addition, the review discusses the advantages and challenges of the current electrochemical and colorimetric nanosensors protocol for heavy metal ion detection. It provides insight into the future directions in the use of the electrochemical and colorimetric nanosensors protocol for heavy metal ion detection.

Potential of Purslane (Portulaca oleracea L.) in Phytoremediation: A Study on the Bioaccumulation and Bio-Transfer of Cadmium, Nickel, and Copper in Contaminated Soils

As industrial and agricultural activities intensify and technology rapidly advances, soil pollution has escalated to alarming levels. The increasing contamination of agricultural areas and the crops cultivated therein has emerged as a significant contemporary issue. Phytoremediation, the use of plants to remove pollutants, is a promising method for mitigating soil heavy metal contamination. 
 This study investigates the bioaccumulation capacity of purslane (Portulaca oleracea L.), a potential phytoremediator, in soils artificially contaminated with cadmium (Cd), nickel (Ni), and copper (Cu). Purslane was cultivated under controlled conditions with varying doses of Cd, Ni, and Cu. After 55 days, the plants were harvested and analysed for heavy metal concentrations in their roots, stems, and leaves. Results demonstrated a direct correlation between environmental heavy metal concentration and plant heavy metal content, with the most significant accumulation occurring in the roots. Leaf chlorophyll content was adversely affected by increased Cd, Ni, and Cu applications. The highest Cu, Ni, and Cd contents were found in the roots at 140 mg kg-1 Cu, 80 mg kg-1 Ni, and 20 mg kg-1 Cd applications, respectively. The bio-transfer coefficient (BTC), a measure of heavy metal transport from the root region to the leaves, was calculated. The BTC values ranged from 0.84-1.09 for Cu, 0.39-0.84 for Ni, and >1 for Cd at the Control and 5 mg Cd kg-1 treatments. 
 These findings suggest that purslane has potential for phytoremediation of heavy metal-contaminated soils, although the bioaccumulation and bio-transfer of heavy metals are dependent on the specific metal and its concentration in the soil. The study also highlights the potential risks associated with the consumption of plants grown in heavy metal-contaminated soils, as heavy metals can accumulate in different plant tissues, potentially entering the food chain.

Heavy metal pollution alters reproductive performance and mate choice in an anuran, Strauchbufo raddei

Understanding the effects of pollution on reproductive performance and sexual selection is crucial for the conservation of biodiversity in an increasingly polluted world. The present study focused on the effect of environmental heavy metal pollution on sexually selected traits, including morphological characteristics and acoustic parameters, as well as mate choice in Strauchbufo raddei, an anuran species widely distributed in Northern China. The results showed that male courtship signals, including forelimb length, forelimb force, and advertisement calls, have evolved under the pressure of heavy metal pollution in young S. raddei. In addition, the breeding age was lower in the polluted areas, and younger individuals had more mating opportunities. However, males with heightened reproductive performance did not show the expected higher individual quality. The current study suggests that exposure to heavy metal pollution can induce stress in males, altering reproductive performance and further disrupting mate choice.

Lignin intervention protected against Pb-induced oxidative stress and hypercholesterolemia via reducing Pb bioaccumulation and regulating gut microbiota in hamster

The widespread environmental heavy metal, Pb, is renowned for inducing irreversible damage to human health. Lignin, an original fiber, emerges as a promising natural candidate for mitigating lead toxicity owing to its exceptional adsorption capacity and biocompatibility. In this study, we conducted an investigation into the potential therapeutic effects of lignin derived from the bamboo (Dendrocalamus Latiforus) shoot shell (BSS-AAL) in alleviating Pb-induced oxidative stress and hypercholesterolemia in hamsters. Our findings demonstrated the remarkable ability of BSS-AAL to reduce Pb accumulation by 27–40% in plasma and 13–84% in tissues. Furthermore, BSS-AAL exerted reparative effects on the antioxidant system, evidenced by substantial reductions in plasma total cholesterol levels by at least 35% and hepatic cholesterol levels by an impressive 66%. Intervention with BSS-AAL also led to favorable alterations in the richness of key microbial genera, including norank_f__Erysipelotrichaceae, unclassified_f__Atopobiaceae, and norank_f__Eubacteriaceae, which are associated with modulating malonaldehyde accumulation, hepatic cholesterol 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, as well as short chain fatty acids synthesis. These findings substantiated BSS-AAL played a vital role in effectively modulating Pb-induced oxidative stress and hypercholesterolemia by reducing Pb accumulation and favorably influencing gut microbiota.

Associations between environmental heavy metals exposure and preserved ratio impaired spirometry in the U.S. adults

We examined 9556 individuals aged 18 to 79 years who had information on spirometry testing and heavy metals and used multivariable logistic or linear regression to evaluate associations between serum levels of cadmium, lead, and mercury and PRISm and lung function in U.S. adults, which were conducted first in all participants, and then separately in never/former smokers and current smokers. The overall prevalence of PRISm was 7.02%. High levels of serum cadmium were significantly associated with PRISm in all individuals, no matter in never/former smokers (quartile 4 vs 1, the OR = 2.517, 95% CI = 1.376–4.604, p-trend = 0.0077) and current smokers (quartile 4 vs 1, the OR = 2.201, 95% CI = 1.265–3.830, p-trend = 0.0020). Serum lead and mercury were not significantly correlated with PRISm, regardless of smoking status. Serum cadmium was strongly correlated with lower FEV1/FVC, regardless of smoking status. Besides, serum cadmium was also significantly related to lower FVC % predicted in never/former smokers and lower FEV1% predicted in current smokers. Serum lead was strongly correlated with lower FVC % predicted and FEV1/FVC in all individuals and never/former smokers. And serum mercury was significantly associated with decrements in FVC % predicted in all individuals and current smokers. These findings demonstrate that serum cadmium is associated with a higher risk of PRISm and lower lung function, with the most significant effect on FEV1/FVC in particular. Our results also indicate that exposure to lead and mercury negatively affects lung function in never/former smokers and current smokers, respectively.

Development of a new method framework to estimate the nonlinear and interaction relationship between environmental factors and soil heavy metals

The intricate and multifaceted nature of soil system profoundly influences the highly complex and often nonlinear changes that soil heavy metals (HM) undergo. Spatial heterogeneity, location and scale variability, and the interaction and superposition among environmental drivers challenged researchers to determine the sophisticated nature of soil HMs changes at the regional scale. This study aims to develop a new method framework and selects Ningbo as the case study to apportion the environmental factors responsible for soil HMs pollution that include Cd, Cr, Pb, Hg, As, Cu, Zn and Ni, focusing on nonlinearity and interaction. We harnessed the Random Forest model to apportion the environmental drivers of soil HM change. The directionality and shape of the nonlinear relationship between HMs and their individual contributors were derived by Partial Dependence Plots. The interactions of multiple drivers were quantitatively assessed by the Conditional Inference Tree. Our results demonstrated that soil HMs in the study area varied spatially. Soil HMs pollution was mitigated by natural factors and anthropogenic factors. The main influencing factors were pH, soil parent material type, enterprise activities, and agricultural application. The effects of some factors on soil HMs showed a monotonic linear trend, but some have apparent threshold effects. The direction of influence on soil HMs will shift when pH and phosphate fertilizer reach a specific value. The addition of enterprises in the area would rarely have an impact on the HMs pollution once it reached around 2 per km2 because of the industrial agglomeration. Soil HM concentrations were mainly from multi-pollutants and were governed by a combination of environmental factors. Our study provided managers and policymakers with site-specific and definite guidelines for preventing and controlling soil HM pollution.

Responses of the gut microbiota to environmental heavy metal pollution in tree sparrow (Passer montanus) nestlings

Gut microbiota plays a critical role in regulating the health and adaptation of wildlife. However, our understanding of how exposure to environmental heavy metals influences the gut microbiota of wild birds, particularly during the vulnerable and sensitive nestling stage, remains limited. In order to investigate the relationship between heavy metals and the gut microbiota, we analyzed the characteristics of gut microbiota and heavy metals levels in tree sparrow nestlings at different ages (6, 9 and 12-day-old). The study was conducted in two distinct areas: Baiyin (BY), which is heavily contaminated with heavy metals, and Liujiaxia (LJX), a relatively unpolluted area. Our result reveled a decrease in gut microbiota diversity and increased inter-individual variation among nestlings in BY. However, we also observed an increase in the abundance of bacterial groups and an up-regulation of bacterial metabolic functions associated with resistance to heavy metals toxicity in BY. Furthermore, we identified a metal-associated shift in the relative abundance of microbial taxa in 12-day-old tree sparrow nestlings in BY, particularly involving Aeromonadaceae, Ruminococcaceae and Pseudomonadaceae. Moreover, a significant positive correlation was found between the body condition of tree sparrow nestlings and the abundance of Bifidobacteriaceae in BY. Collectively, our findings indicate that the gut microbiota of tree sparrow nestlings is susceptible to heavy metals during early development. However, the results also highlight the presence of adaptive responses that enable them to effectively cope with environmental heavy metal pollution.

Morphological brain changes in Alzheimer's-like disease in rats

Heavy metals are reported as neurodegenerative disorders progenitor. They play a role in the abnormal amyloid beta 40 (Aβ40) protein concentrations, the main hallmarks of Alzheimer's disease (AD). The aim of the present work is to study the morphological ultrastructural changes by transmission electron microscopy and measurements of Aluminium and Aβ40 protein concentration in rats’ hippocampus due to Alzheimer's-like disease in rats. Fifty male Albino Wistar rats were divided into five groups; the first group acted as the control group, while the other four groups each received 100 mg/kg of aluminium chloride (AlCl3) over the course of 2, 4, 6, and 8 weeks. The results indicated significant increase (p˂0.05) of alumininm and significant decrease (p˂0.05) of Aβ40 in the hippocampus of rats due to AlCl3 administration starting from 2 and 6 weeks, respectivily. Histological ultrastructural hippocampus changes were observed starting from 2 weeks of AlCl3 administration to reach the most damaged structure after 8 weeks, where its nucleus appeared shrunken with a condensed chromatin beside marked loss of the cytoplasmic organelles including mitochondria, rER, and Golgi apparatus. Also, vacuolation was clearly observed at the remnants of cytoplasm. According to the results of the current investigation, there is a significant link between multiple exposure to environmental heavy metals and the pathophysiology of AD by altering Aβ 40, which causes neuronal death, as well as histological and ultrastructural changes in the rat hippocampus.

Mechanism Exploration of Environmental Pollutants on Premature Ovarian Insufficiency: a Systematic Review and Meta-analysis.

As a public health problem, premature ovarian insufficiency leads to infertility or sub-fertility. In addition to premature ovarian insufficiency (POI) increases the lifetime risk of bone fragility, cardiovascular disease, and cognitive impairment. To investigate the effects of environmental pollutants on the occurrence of POI and explore its mechanism, we conducted a computer search for articles published in electronic databases by December 13, 2022. Three reviewers independently examined all included studies and scored the qualities of included studies using the Newcastle-Ottawa Scale criteria. In this meta-analysis, eight clinical studies as well as ten preclinical findings showed a pooled OR of 2.331 and 95% CI of 1.968-2.760. This confirms that environmental pollutants, including POPs, heavy metals, PAEs, PAHs, cosmetic and pharmaceutical products, and cigarette smoke, are indeed significant risk factors for POI. In addition, it is demonstrated from the results of this study that signaling pathway of calcium and PI3K Akt and Xpnpep2, Col1, Col3, Col4, Cx43, Egr3, Tff1, and Ptgs2 genes may all be involved in the process. Environmental pollutants, including POPs, heavy metals, PAEs, PAHs, cosmetic and pharmaceutical products, and cigarette smoke, are indeed significant risk factors for POI.

Blood Levels of Environmental Heavy Metals are Associated with Poorer Iron Status in Ugandan Children: A Cross-Sectional Study

BackgroundIron deficiency (ID) and environmental exposure to metals frequently co-occur among Ugandan children, but little is known about their associations, although iron and other divalent metals share the same intestinal absorption transporter, divalent metal transporter 1 (DMT1). ObjectivesWe examined associations between iron status and blood concentrations of lead, manganese (Mn), cobalt (Co), and cadmium, both singly and as a mixture. MethodsWe used data on sociodemographic status, iron biomarkers, and blood concentrations of heavy metals collected from a cross-sectional survey of 100 children aged 6–59 mo in Kampala, Uganda. We compared blood concentrations of metals in ID with iron-sufficient children. We examined associations between a metal mixture and iron biomarkers using multiple linear regression and weighted quintile sum regression. ResultsThe median (interquartile range) blood Mn (μg/L) was higher in ID children defined by soluble transferrin receptor (sTfR) and ferritin (ID compared with iron-sufficient children): (sTfR [21.3 {15.1, 28.8}, 11.2 {8.6, 18.5}], ferritin [19.5 {15.0, 27.2}, 11.2 {8.8, 19.6}]; P < 0.001 for both). Similarly, the median (interquartile range) blood Co (μg/L) was higher in ID children by ferritin ([0.5 {0.4, 0.9}, 0.4 {0.3, 0.5}], P = 0.05). Based on the multiple linear regression results, higher blood Co and Mn were associated with poorer iron status (defined by all 4 iron indicators for Co and by sTfR for Mn). The weighted quintile sum regression result showed that higher blood concentrations of a metal mixture were associated with poorer iron status represented by sTfR, ferritin, and hepcidin, mainly driven by Co and Mn. ConclusionsOur study findings suggest that poorer iron status is associated with overall heavy metal burden, predominantly Co and Mn, among Ugandan children. Further prospective studies should confirm our primary findings and investigate the combined effects of coexposures to neurotoxicants on the neurodevelopment of young children.

VPS41-mediated incomplete autophagy aggravates cadmium-induced apoptosis in mouse hepatocytes

Exposure to cadmium (Cd), an environmental heavy metal contaminant, is a serious threat to global health that increases the burden of liver diseases. Autophagy and apoptosis are important in Cd-induced liver injury. However, the regulatory mechanisms involved in the progression of Cd-induced liver damage are poorly understood. Herein, we investigated the role of vacuolar protein sorting 41 (VPS41) in Cd-induced autophagy and apoptosis in hepatocytes. We used targeted VPS41 regulation to elucidate the mechanism of Cd-induced hepatotoxicity. Our data showed that Cd triggered incomplete autophagy by downregulating VPS41, aggravating Cd-induced hepatocyte apoptosis. Mechanistically, Cd-induced VPS41 downregulation interfered with the mTORC1-TFEB/TFE3 axis, leading to an imbalance in autophagy initiation and termination and abnormal activation of autophagy. Moreover, Cd-induced downregulation of VPS41 inhibited autophagosome–lysosome fusion, leading to blocked autophagic flux. This triggers incomplete autophagy, which causes excessive P62 accumulation, accelerating Caspase-9 (CASP9) cleavage. Incomplete autophagy blocks clearance of cleaved CASP9 (CL-CASP9) via the autophagic pathway, promoting apoptosis. Notably, VPS41 overexpression alleviated Cd-induced incomplete autophagy and apoptosis, independent of the homotypic fusion and protein sorting complex. This study provides a new mechanistic understanding of the relationship between autophagy and apoptosis, suggesting that VPS41 is a new therapeutic target for Cd-induced liver damage.

Mechanisms of Cadmium Tolerance and Detoxification in Two Ornamental Plants

Cadmium (Cd) is an important environmental heavy metal and one of the main soil pollutants in southwest China and even the Yangtze River Basin because of its toxicity to plants and humans. To clarify the potential of Euryops pectinatus L. and Gardenia jasminoides J. and the mechanism they use to remediate Cd-contaminated soil, a soil pot experiment with 0, 5, 10, 20, and 40 mg kg−1 of Cd was used to investigate the accumulation characteristics, subcellular distribution, chemical forms, and the antioxidative defense systems of the two ornamental plants. When the concentration of Cd was below 40 mg kg−1, it promoted the growth of E. pectinatus shoots, and the tolerance index (TI) was &gt;1. However, 20–40 mg kg−1 Cd significantly inhibited the growth of G. jasminoides, and the TI was &lt;1. The shoots of both varieties accumulated more Cd than the roots, and the E. pectinatus shoots accumulated more Cd (1.45 mg plant−1) than those of G. jasminoides (0.71 mg plant−1). The Cd in E. pectinatus and G. jasminoides was primarily distributed in the soluble fraction (52.83–68.97%) and cell walls (44.62–54.98%), respectively. Higher proportions of Cd bound to NaCl and acetic acid (HAc) in E. pectinatus (55.32–73.44%) than in G. jasminoides (42.94–61.58%), while the inorganic and water-soluble proportions of Cd bound in the opposite manner. E. pectinatus maintained high activities of antioxidant enzymes under Cd treatments, and its levels of malondialdehyde (MDA) and relative electrical conductivity (REC) were comparable to those of the control. Nonetheless, G. jasminoides had low levels of activity of antioxidant enzymes, but its levels of MDA and REC were significantly higher than those of the control under the 20–40 mg kg−1 Cd treatment. Therefore, both types of plants have a strong ability to tolerate and accumulate Cd, which makes them suitable for the remediation of Cd-polluted soil. However, E. pectinatus is more effective at remediating Cd and tolerant to it than G. jasminoides. These plants utilize different mechanisms to detoxify Cd.

Toxicity Evaluation, Oxidative, and Immune Responses of Mercury on Nile Tilapia: Modulatory Role of Dietary Nannochloropsis oculata.

The current study evaluated the potential ameliorative effect of a dietary immune modulator, Nannochloropsis oculata microalga, on the mercuric chloride (HgCl2)-induced toxicity of Nile tilapia. Nile tilapia (45-50g) were fed a control diet or exposed to ¼ LC50 of HgCl2 (0.3mg/L) and fed on a medicated feed supplemented with N. oculata (5% and 10% (50 or 100g/kg dry feed)) for 21days. Growth and somatic indices, Hg2+ bioaccumulation in muscles, and serum acetylcholinesterase (AChE) activity were investigated. Antioxidant and stress-related gene expression analyses were carried out in gills and intestines. Histopathological examinations of gills and intestines were performed to monitor the traits associated with Hg2+ toxicity or refer to detoxification. Hg2+ toxicity led to significant musculature bioaccumulation, inhibited AChE activity, downregulated genes related to antioxidants and stress, and elicited histopathological changes in the gills and intestine. Supplementation with N. oculata at 10% was able to upregulate the anti-oxidative-related genes while downregulated the stress apoptotic genes in gills and intestines compared to the unexposed group. In addition, minor to no histopathological traits were detected in the gills and intestines of the N. oculata-supplemented diets. Our data showed the benefit of dietary N. oculata in suppressing Hg2+ toxicity, which might support its efficacy as therapeutic/preventive agent to overcome environmental heavy metal pollution in aquatic habitats.

Cadmium promotes colorectal cancer metastasis through EGFR/Akt/mTOR signaling cascade and dynamics

Cadmium (Cd) is a hazardous environmental heavy metal with a prolonged biological half-life. Due to the main route of foodborne exposure, the intestinal tract is particularly vulnerable to Cd-induced toxicity. However, the chronic toxicity and underlying mechanisms of Cd in intestinal diseases, including colorectal cancer (CRC), still remain vague. Herein, we aim to investigate the long-term effects of Cd exposure on CRC development and the key signaling event. Our findings indicate that chronic and low-dose exposure to Cd promoted the invasion and metastasis capability of CRC cells in vitro and in mice, with a marginal increase in cell growth. The expression of cell junction-related genes was down-regulated while those molecules that facilitate cell mobility were significantly increased by Cd exposure. Epidermal growth factor receptor (EGFR) signaling was identified to play the dominant role in Cd-promoted CRC metastasis. Interestingly, Cd activated EGFR in a non-canonical manner that exhibited distinct signaling dynamics from the canonical ligand. In contrast to EGF, which induced transient EGFR signaling and ERK activation, Cd promoted sustained EGFR signaling to trigger Akt/mTOR cascade. The unique signaling dynamics of EGFR induced by Cd provoked responses that preferably enhanced the metastatic capacity rather than the growth. Furthermore, blockade of EGFR abrogated the promoting effects of Cd on the liver metastasis of CRC cells. In conclusion, this study provides a better understanding of the long-term influences of environmental Cd on CRC metastasis and reveals the unique EGFR signaling dynamics induced by Cd exposure.

Impacts of heavy metal exposure on the prostate of murine models: Mechanisms of toxicity

Heavy metals are elements found into the environment mainly due to anthropogenic activities. Naturally occurring and higher released doses cause disorders in the prostate, which depends on appropriate hormonal regulation, and exposure to heavy metals may impair prostate homeostasis. The current work highlighted the main mechanisms of toxicity of different environmental heavy metal contaminants, such as aluminum, arsenic, cadmium, chromium, lead, mercury, and nickel, and their impacts found in the prostate morphophysiology of murine models. The repercussions triggered by heavy metals on the prostate include hormonal imbalance and oxidative damage, leading to morphological alterations, which can vary according to the chemical properties of each element, exposure time and concentration, and age. The information of altered biological pathways and its impacts on the prostate of exposed murines are related to human outcomes being useful in the real context of human exposure.

Arrestin domain-containing protein 1-mediated microvesicles (ARMMs) protect against cadmium-induced neurotoxicity

Exposure to environmental heavy metals such as cadmium (Cd) is often linked to neurotoxicity but the underlying mechanisms remain poorly understood. Here we show that Arrestin domain-containing protein 1 (ARRDC1)-mediated microvesicles (ARMMs)–an important class of extracellular vesicles (EVs) whose biogenesis occurs at the plasma membrane–protect against Cd-induced neurotoxicity. Cd increased the production of EVs, including ARMMs, in a human neural progenitor cell line, ReNcell CX (ReN) cells. ReN cells that lack ARMMs production as a result of CRISPR-mediated ARRDC1 knockout were more susceptible to Cd toxicity as evidenced by increased LDH production as well as elevated level of oxidative stress markers. Importantly, adding ARMMs back to the ARRDC1-knockout ReN cells significantly reduced Cd-induced toxicity. Consistent with this finding, proteomics data showed that anti-oxidative stress proteins are enriched in ARMMs secreted from ReN cells. Together our study reveals a novel protective role of ARMMs in Cd neurotoxicity and suggests that ARMMs may be used therapeutically to reduce neurotoxicity caused by exposure to Cd and potentially other metal toxicants.