Environmental Heavy Metal Pollution Research Articles

Stabilization of heavy metals in solid waste and sludge pyrolysis by intercalation-exfoliation modified vermiculite

Increasing amounts of solid waste and sludge have created many environmental management problems. Pyrolysis can effectively reduce the volume of solid waste and sludge, but there is still the problem of heavy metal contamination, which limits the application of pyrolysis in environmental management. The intercalated-exfoliated modified vermiculite (IEMV) by intercalators of sodium dodecylbenzene sulfonate, hexadecyltrimethylammonium bromide and octadecyltrimethylammonium bromide were used to control the release of Cd, Cr, Cu, Zn and Pb during pyrolysis process of sludge or solid waste. The retention of heavy metals in sludge was generally better than that in solid waste. The IEMV by octadecyltrimethylammonium bromide as the intercalator calcined 800 °C (STAB-800) was the best additive for heavy metal retention, and the retention of Cr, Cu and Zn was significantly better than that of Pb and Cd. Cr, Cu, Zn and Pb were at low risk, while Cd had considerable risk under certain circumstances. New models were proposed to comprehensively evaluate the results of the risk and forms of heavy metals, and the increasing temperature was beneficial in reducing the hazards of heavy metals by the addition of STAB-800. The reaction mechanism of heavy metals with vermiculite was revealed by simulation of reaction sites, Fukui Function and Frontier Molecular Orbital. Thermal activation-intercalated-exfoliated modified vermiculite (T-IEMV) is more reactive and had more active sites for heavy metals. Mg atoms and outermost O atoms are the main atoms for T-IEMV to react with heavy metals. The Cr, Cu and Zn have better adsorption capacity by T-IEMV than Pb and Cd. This study provides a new insight into managing solid waste and sludge and controlling heavy metal environmental pollution.

Se Alleviated Pb-Caused Neurotoxicity in Chickens: SPS2-GPx1-GSH-IL-2/IL-17-NO Pathway, Selenoprotein Suppression, Oxidative Stress, and Inflammatory Injury.

Lead (Pb), a heavy metal environmental pollutant, poses a threat to the health of humans and birds. Inflammation is one of the most common pathological phenomena in the case of illness and poisoning. However, the underlying mechanisms of inflammation remain unclear. The cerebellum and the thalamus are important parts of the nervous system. To date, there have been no reports of Pb inducing inflammation in animal cerebellums or thalami. Selenium (Se) can relieve Pb poisoning. Therefore, we aimed to explore the mechanism by which Se alleviates Pb toxicity to the cerebellums and thalami of chickens by establishing a chicken Pb or/and Se treatment model. Our results demonstrated that exposure to Pb caused inflammatory damage in cerebellums and thalami, evidenced by the characteristics of inflammation, the decrease in anti-inflammatory factors (interleukin (IL)-2 and interferon-γ (INF-γ)), and the increase in pro-inflammatory factors (IL-4, IL-6, IL-12β, IL-17, and nitric oxide (NO)). Moreover, we found that the IL-2/IL-17-NO pathway took part in Pb-caused inflammatory injury. The above findings were reversed by the supplementation of dietary Se, meaning that Se relieved inflammatory damage caused by Pb via the IL-2/IL-17-NO pathway. In addition, an up-regulated oxidative index malondialdehyde (MDA) and two down-regulated antioxidant indices (glutathione (GSH) and total antioxidant capacity (TAC)) were recorded after the chickens received Pb stimulation, indicating that excess Pb caused an oxidant/antioxidant imbalance and oxidative stress, and the oxidative stress mediated inflammatory damage via the GSH-IL-2 axis. Interestingly, exposure to Pb inhibited four glutathione peroxidase (GPx) family members (GPx1, GPx2, GPx3, and GPx4), three deiodinase (Dio) family members (Dio1, Dio2, and Dio3), and fifteen other selenoproteins (selenophosphate synthetase 2 (SPS2), selenoprotein (Sel)H, SelI, SelK, SelM, SelO, SelP1, SelPb, SelS, SelT, SelU, and selenoprotein (Sep)n1, Sepw1, Sepx1, and Sep15), suggesting that Pb reduced antioxidant capacity and resulted in oxidative stress involving the SPS2-GPx1-GSH pathway. Se supplementation, as expected, reversed the changes mentioned above, indicating that Se supplementation improved antioxidant capacity and mitigated oxidative stress in chickens. For the first time, we discovered that the SPS2-GPx1-GSH-IL-2/IL-17-NO pathway is involved in the complex inflammatory damage mechanism caused by Pb in chickens. In conclusion, this study demonstrated that Se relieved Pb-induced oxidative stress and inflammatory damage via the SPS2-GPx1-GSH-IL-2/IL-17-NO pathway in the chicken nervous system. This study offers novel insights into environmental pollutant-caused animal poisoning and provides a novel theoretical basis for the detoxification effect of Se against oxidative stress and inflammation caused by toxic pollutants.

Synergistic regulation of nanocomposite interlayered forward osmosis membranes with 1D/2D nanostructures for enhanced heavy metal retention

The treatment of heavy metal wastewater poses a significant challenge due to its adverse environmental consequences and potential hazards to human well-being, necessitating effective and sustainable solutions. Forward osmosis (FO) is an efficient and low-energy separation technology that serves as an effective strategy to address this issue. However, it still faces the trade-off between water permeability and selectivity, which directly impacts the solute separation efficiency and retention characteristics. In this study, a covalent organic framework (COF) interlayer was introduced via in-situ growth, and the surface properties of polyamide (PA) were synergistically regulated by amine-functionalized multi-wall carbon nanotubes (MWCNT-NH2), resulting in a 1D/2D nanocomposite interlayered FO membrane with a high crosslinking density, improved hydrophilicity, excellent stability, and antifouling properties. The synergistic effect of COF and MWCNT-NH2 led to an increase in the concentration of MPD participating in interfacial polymerization (IP) and a decrease in MPD diffusion rate. These improvements led to enhanced water permeability and selectivity, as well as outstanding retention efficiencies for heavy metal ions (Cr3+, Ni2+), exceeding 99.2 %. Therefore, this study holds significant implications for targeted application development of high-efficiency FO membranes in the future, demonstrating practical value in the treatment of heavy metal wastewater and environmental pollution control.

Anthocyanins from Lycium ruthenicum Murray Mitigate Cadmium-Induced Oxidative Stress and Testicular Toxicity by Activating the Keap1/Nrf2 Signaling Pathway.

Cadmium (Cd) is a hazardous heavy metal environmental pollutant that has carcinogenic, teratogenic, and mutagenic properties. Excessive exposure to Cd can induce oxidative stress, which greatly harms the male reproductive system. Anthocyanins have remarkable antioxidative, anti-inflammatory, and anti-stress properties. In this study, we investigated the effects of anthocyanins and the underlying mechanisms through which anthocyanins mitigate Cd-induced reproductive damage. We isolated and purified Lycium ruthenicum Murray anthocyanin extract (LAE) and performed UHPLC-MS/MS to identify 30 different anthocyanins. We established an ICR mouse Cd injury model by administering 5 mg/kg/day CdCl2 for 28 consecutive days. LAE at 500 mg/kg/day effectively ameliorated testicular damage and preserved spermatogenesis. The mice in the LAE-treated group had elevated testosterone and inhibin B levels. Additionally, the treatment restored the activity of antioxidant enzymes, including T-SOD, CAT, and GR, and substantially increased the levels of the non-enzymatic antioxidant GSH. Research findings indicate that LAE can activate the SIRT1/Nrf2/Keap1 antioxidant pathway. This activation is achieved through the upregulation of both the SIRT1 gene and protein levels, leading to the deacetylation of Nrf2. Moreover, LAE reduces the expression of Keap1, alleviating its inhibitory effect on Nrf2. This, in turn, facilitates the uncoupling process, promoting the translocation of Nrf2 to the nucleus, where it governs downstream expression, including that of HO-1 and GPX1. LAE effectively mitigated toxicity to the reproductive system associated with exposure to the heavy metal Cd by alleviating oxidative stress in the testes.

Toxic effect of chromium on nonspecific immune, bioaccumulation, and tissue structure of Urechis unicinctus.

The contamination of toxic heavy metals in aquatic environments has garnered significant global attention due to its detrimental effects on marine organisms and human health. Hexavalent chromium is a typical environmental and occupational heavy metal pollutant, identified as carcinogenic heavy metal. This study aimed to assess the impact of different Cr (VI) concentrations (0.05-2.5 mg/L) on Urechis unicinctus (U. unicinctus) by investigating bioaccumulation, antioxidant defense system, expression of resistance-related genes, and histological issues. A clear concentration-effect relationship was observed in the bioaccumulation of Cr (VI) in muscle tissues of U. unicinctus. Moreover, exposure to Cr (VI) can alter the activities of lysozyme (LSZ), catalase (CAT), and superoxide dismutase (SOD) to enhance cellular defense mechanisms in U. unicinctus. Likewise, maintained the normal protein structure and functional stability by regulating protein folding. The heat shock cognitive protein (HSC70) gene showed an upward and then downward trend after Cr (VI) exposure. At 12 h, the HSC70 gene expression reached the maximum values of 4.75 and 4.61-fold in the 0.1 and 1.5 mg/L groups, respectively. The organism produced a large number of free radicals, and elevated level of metallothionein (MT) was used to scavenge free radicals and alleviate oxidative stress. Additionally, histopathological examination revealed disorganization in the midgut, atrophic changes in intestinal connective tissue, uneven distribution in respiratory tissues, and irregular shape with a significant reduction in epithelial cells within the gastric cavity. These findings can serve as a valuable reference for elucidating the toxicity mechanisms of heavy metals towards marine benthic organisms and enhancing water environment monitoring strategies.

A study of environmental pollution and risk of heavy metals in the bottom water and sediment of the Chaohu Lake, China.

Most of the existing research for heavy metals in water at present is focusing on surface water. However, potential environmental risk of heavy metals in the bottom water of lakes cannot be ignored. In this study, the content, distribution, and speciation of nine heavy metals (As, V, Cr, Co, Ni, Cu, Zn, Cd, and Pb) in the bottom water and sediment of Chaohu Lake were studied. Some pollution assessment methods were used to evaluate the environmental effect of heavy metals. Positive matrix factorization was conducted to investigate the potential sources of heavy metals in sediment. The contents of heavy metals in the bottom water of Chaohu Lake mean that its environmental pollution can be ignored. In sediment, Cd and Zn have showed stronger ecological risk. pH and redox potential are more likely to affect the stability of heavy metals in the bottom water of Chaohu Lake during the dry reason. Industrial sources (16%) are no longer the largest source of heavy metal pollution; traffic sources (33.6%) and agricultural sources (23.4%) have become the main sources of pollution at present. This study can provide some support and suggestions for the treatment of heavy metals in lakes.

Effect of EDDS on the rhizosphere ecology and microbial regulation of the Cd-Cr contaminated soil remediation using king grass combined with Piriformospora indica

The negative impacts of soil heavy metals composite pollution on agricultural production and human health are becoming increasingly prevalent. The applications of green chelating agents and microorganisms have emerged as promising alternate methods for enhancing phytoremediation. The regulatory effects of root secretion composition, microbial carbon source utilization, key gene expression, and soil microbial community structure were comprehensively analyzed through a combination of HPLC, Biolog EcoPlates, qPCR, and high-throughput screening techniques. The application of EDDS resulted in a favorable rhizosphere ecological environment for the king grass Piriformospora indica, characterized by a decrease in soil pH by 0.41 units, stimulation of succinic acid and fumaric acid secretion, and an increase in carbon source metabolic activity of amino acids and carbohydrates. Consequently, this improvement enhanced the bioavailability of Cd/Cr and increased the biomass of king grass by 25.7%. The expression of dissimilatory iron-reducing bacteria was significantly upregulated by 99.2%, while there was no significant difference in Clostridium abundance. Furthermore, the richness of the soil rhizosphere fungal community (Ascomycota: 45.8%, Rozellomycota: 16.7%) significantly increased to regulate the proportion of tolerant microbial dominant groups, promoting the improvement of Cd/Cr removal efficiency (Cd: 23.4%, Cr: 18.7%). These findings provide a theoretical basis for the sustainable development of chelating agent-assisted plants-microorganisms combined remediation of heavy metals in soil.

Türkiye'deki Ocaklardan Alınan Doğal Kil Mineral Örneklerinde Ağır Metal Konsantrasyonlarının Belirlenmesi

Environmental pollution of heavy metals is increasingly becoming a problem and has become of great concern due to the adverse effects it is causing around the world. Today, various chemical, biological, and physical pollutants arising as a result of rapidpopulation growth, industrialization, and excessive mining activities have become a major problem that adversely affects people, animals, plants, organisms, and ecosystems all over the world. Sepiolite is a clay mineral containing hydrated magnesium silicate and widely used in construction, agriculture, food, fertilizer, pharmaceutical, detergent, cosmetics, paint, paper, etc. The average concentrations of Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Rb, Sr, Zr, Cd, Sn, Ba and Pb analyzed in sepiolite samples collected from three quarries (Polatlı, Beylikova, and Sivrihisar) located in the Central Anatolian Region of Turkey using EDXRF spectroscopy were found as 5456.5, 361.0, 42.0, 15.5, 65.2, 3831.5, 8.6, 23.7, 7.8, 11.8, 5.3, 13.7, 1183.2, 25.3, 3.7, 7.2, 131.9 and 5.3 mg/kg, respectively. The average enrichment factor values of V, Cr, Co, Ni, Cu, Zn, As, Sr, Cd, Sn, Ba, and Pb indicated minimal to extremely high enrichment in sepiolite. The values of non-carcinogenic risk index and cancer risk estimated to evaluate potentially health risks caused by PTEs in sepiolite samples were within the acceptable limit and the safe range except for the Beylikova quarry.

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.

Neuropathological profile of the African Giant Rat brain (Cricetomys gambianus) after natural exposure to heavy metal environmental pollution in the Nigerian Niger Delta.

Pollution by heavy metals is a threat to public health because of the adverse effects on multiple organ systems including the brain. Here, we used the African giant rat (AGR) as a novel sentinel host to assess the effect of heavy metal accumulation and consequential neuropathology upon the brain. For this study, AGR were collected from distinct geographical regions of Nigeria: the rain forest region of south-west Nigeria (Ibadan), the central north of Nigeria (Abuja), and in oil-polluted areas of south Nigeria (Port-Harcourt). We found that zinc, copper, and iron were the major heavy metals that accumulated in the brain and serum of sentinel AGR, with the level of iron highest in animals from Port-Harcourt and least in animals from Abuja. Brain pathology, determined by immunohistochemistry markers of inflammation and oxidative stress, was most severe in animals from Port Harcourt followed by those from Abuja and those from Ibadan were the least affected. The brain pathologies were characterized by elevated brain advanced oxidation protein product (AOPP) levels, neuronal depletion in the prefrontal cortex, severe reactive astrogliosis in the hippocampus and cerebellar white matter, demyelination in the subcortical white matter and cerebellar white matter, and tauopathies. Selective vulnerabilities of different brain regions to heavy metal pollution in the AGR collected from the different regions of the country were evident. In conclusion, we propose that neuropathologies associated with redox dyshomeostasis because of environmental pollution may be localized and contextual, even in a heavily polluted environment. This novel study also highlights African giant rats as suitable epidemiological sentinels for use in ecotoxicological studies.

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.

The spatial distribution and source apportionment of heavy metals in soil of Shizuishan, China

Environmental pollution of heavy metals in the typical coal industrial city should be paid more attentions nowadays. The spatial distribution and source apportionment of 8 heavy metals (i.e., Cd, Cr, Co, Zn, Ni, Cu, Pb and Mn) from topsoil samples (158) of Shizuishan city in Ningxia Hui Autonomous Region of China were investigated using principal component analysis/absolute principal component scores (PCA/APCS) receptor model and geographic information system (GIS). These results showed that the mean concentrations of Cd, Cr, Co, Zn, Ni, Cu and Pb were higher than their soil background values in Ningxia. 99.36% of soil samples were heavily polluted according to analysis of integrated Nemerow pollution index (PN), whereas 81.65% of soil samples exhibited the highly strong potential ecological risk by ERI (the comprehensive of potential ecological risk index) values. The source apportionment results showed that eight heavy metals in soil were mainly from natural (32.39%), industrial (26.56%), traffic emission/coal consumption (20.18%) and atmospheric deposition source (12.73%). Typically, Zn, Mn and Ni were derived from natural source, whereas Cr and Co were mainly derived from industrial sources. Cu was from the multiple sources, whereas Pb and Cd were weighted primarily from traffic emission/coal consumption source and atmospheric deposition source, respectively. These findings were crucial for the prevention and control of heavy metals pollution in Shizuishan city.

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.

Celeriac as ionphore for green Co+2 selective PVC membrane electrode by experimental and theoretical investigation

Environmental pollution of heavy metals is increasingly becoming a problem and has become of great concern due to the adverse effects it is causing around the world. Many techniques were applied to detect, to determine and to remove. In this study, a simple electrochemical methods was used. The preparation of a novel PVC membrane green sensor was conducted for the Co+2 ion considering the Celeriac alcoholic extract. The sensor has a 29.5 mV decade−1 Nernstian slope within an extensive range of linear concentrations from 0.38 × 10−3 to 0.08 × 10−3 while possessing a 0.03 × 10−4. M detection limit. The response time reported for the proposed sensor is < 10 s, and it is useable for a minimum period of one month with no significant potential divergence. The potentiometric response independence from the test solution pH was also confirmed at pH ranges of 5.8–11. The introduced electrode is appropriately selective in various transition metal ions. The reactivity (chemical and electromechanical) characteristics, including electronegativity, electrophilicity, chemical potential, band gap, softness, and hardness were calculated using the DFT technique. As shown by the results, the apijin was highly reactive in different Celeriac compounds.

Flower-like imide covalent organic framework as an electrochemical platform catcher for simultaneous sensitive detection of trace Pb(II) and Cd(II)

Heavy metal pollution in aquatic environment poses an enormous risk to ecosystems and human health. In this study, a flowerlike covalent organic framework (TpTa-COF) was synthesized by one-step solvothermal method with 2,4,6-triformylphloroglucinol (Tp) and 4, 4-diamino-tribiphenyl (Ta) as building elements. Then it was used as an effective trap to establish an electrochemical sensing platform for simultaneously sensitive detection of trace Pb(II) and Cd(II) in water. This three-dimensional flower-shaped structure exhibited exceptional adsorption capacity, large surface area, high stability, and all of which enhanced the detection sensitivity of the sensor and facilitated full contact between ions and substrate. The high oxygen content in the structure provided abundant active sites for Pb(II) and Cd(II), further enhancing its electrochemical response. The constructed sensor exhibited a linear response to Pb(II) within the concentration range of 3–60 µg/L under the optimal conditions, with a detection limit of 0.16 µg/L. Similarly, a linear response was observed for Cd(II) in the concentration range of 5–60 µg/L, with a detection limit of 0.29 µg/L. Low detection limits, excellent sensitivity, and strong stability were all features of the suggested approach. It has been successfully employed in determining Pb(II) and Cd(II) concentrations in two actual water samples. XPS, SEM-EDS mapping, and density functional theory calculations confirmed that TpTa-COF interacted with metal ions mainly via coordination with carbonyl oxygen atoms in the structure. Overall, these findings will broaden the applications of COF in the field of chemical analysis.

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.

Heavy Metals, Their Phytotoxicity, and the Role of Phenolic Antioxidants in Plant Stress Responses with Focus on Cadmium: Review.

The current state of heavy metal (HM) environmental pollution problems was considered in the review: the effects of HMs on the vital activity of plants and the functioning of their antioxidant system, including phenolic antioxidants. The latter performs an important function in the distribution and binding of metals, as well as HM detoxification in the plant organism. Much attention was focused on cadmium (Cd) ions as one of the most toxic elements for plants. The data on the accumulation of HMs, including Cd in the soil, the entry into plants, and the effect on their various physiological and biochemical processes (photosynthesis, respiration, transpiration, and water regime) were analyzed. Some aspects of HMs, including Cd, inactivation in plant tissues, and cell compartments, are considered, as well as the functioning of various metabolic pathways at the stage of the stress reaction of plant cells under the action of pollutants. The data on the effect of HMs on the antioxidant system of plants, the accumulation of low molecular weight phenolic bioantioxidants, and their role as ligand inactivators were summarized. The issues of polyphenol biosynthesis regulation under cadmium stress were considered. Understanding the physiological and biochemical role of low molecular antioxidants of phenolic nature under metal-induced stress is important in assessing the effect/aftereffect of Cd on various plant objects-the producers of these secondary metabolites are widely used for the health saving of the world's population. This review reflects the latest achievements in the field of studying the influence of HMs, including Cd, on various physiological and biochemical processes of the plant organism and enriches our knowledge about the multifunctional role of polyphenols, as one of the most common secondary metabolites, in the formation of plant resistance and adaptation.

Combination of Superabsorbent Polymer And Vetiver Grass As A Remedy For Lead-Polluted Soil

Heavy metal pollution in the soil environment is a worldwide environmental problem as it has negative effects on both human health and the environment. Remediation of heavy metal-contaminated soil is essential to improve soil quality, provide land resources for agricultural production, and protect human and animal health and the ecological environment. There is the possibility of remediating these contaminated soils through the use of several heavy metal absorbing plants and Superabsorbent polymers. Superabsorbent polymers (SAPs) are 3D polymer networks having hydrophilic nature, which can swell, absorb and hold a large amount of water or aqueous solutions in their network. This study evaluates the effect of superabsorbent polymer on Pb absorption capacity of Vetiver (Vetiveria zizanioides.L) that was grown on contaminated soil in Trai Cau iron ore dumpsite, Dong Hy district, Thai Nguyen province. The experiment was designed with five recipes and three replicates. The contents of SAP studied were 0, 0.6, 0.8, and 1.0 g/kg of soil. Uncontaminated soil was used as the control treatment. In the supplemented recipe of SAP, Vetiver showed better Pb treatment efficiency than the recipes without adding polymers. After 120 days of planting, SAP increased the tolerance and Pb absorption of Vetiver, improving soil properties. The best Pb treatment efficiency is achieved when using SAP with content from 0.8-1.0 g/kg soil.

Controllable synthesis of yellow emissive carbon dots by mild heating process and their utility as fluorescent test paper for detection of mercury(II) ions assistants by smartphone

The security of food and drink water is of great concern in our daily life, because the threat from heavy metals pollution in environment is extensively existed. Carbon dots (CDs) is promising for a wide range of applications because of its excellent chemical and optical properties. Herein, yellow emissive carbon dots (YCDs) were constructed by a facile mild condition. The YCDs emitted bright emission at 562 nm with excitation of 420 nm and the quantum yield of 17.44%. The fluorescence of YCDs can be utilized of sensing Hg2+ with limit of 16.8 nM. The mechanism of detection for Hg2+ can be attributed to static quenching effect (SQE) and dynamic quenching effect (DQE) process. A fluorescent portable paper detection platform based on YCDs integrated with a smartphone APP were developed for real-time and rapid analysis of Hg2+ with limit of 0.11 μM. Notably, YCDs were successfully employed to the detection of Hg2+ in various food and real water with recoveries of 97.50 ± 2.63% – 108.64 ± 0.15%, indicated satisfied sensing performance and excellent environmental tolerance. The fluorescence sensing system based on YCDs provided a reference for the construction of portable sensors for hazardous substance monitoring.

Material and Waste Flow Analysis for Environmental and Economic Impact Assessment of Inorganic Acid Leaching Routes for Spent Lithium Batteries’ Cathode Scraps

With the development trend and technological progress of lithium batteries, the battery market is booming. This means that the demand for lithium batteries has increased significantly, resulting in a large number of discarded lithium batteries. The consumption of plenty of lithium batteries may lead to the scarcity and expending of relevant raw material metal resources, as well as serious heavy metal environmental pollution. Therefore, it is of great significance to recycle valuable metal resources from discarded lithium batteries. The proper recycling of these valuable metals can reduce the shortage of mineral resources and environmental hazards caused by a large number of scrapped vehicle batteries. Recently, different systematic approaches have been developed for spent lithium battery recovery. However, most of these approaches do not account for the hidden costs incurred from various processing steps. This work is determined by the concept of material flow cost accounting (MFCA). Hence, in this research, a MFCA-based approach is developed for the leaching process of spent lithium batteries recovery, taking into consideration the hidden costs embedded in process streams. In this study, hydrochloric acid had the worst leaching efficiency due to its high solid-to-liquid ratio and the lowest acid concentration, so it was excluded in the first stage selection. It takes TWD 16.03 and TWD 24.10 to leach 10 g of lithium battery powder with sulfuric acid and nitric acid, respectively. The final sulfuric acid was the acid solution with the highest leaching efficiency and relatively low cost among inorganic acids.