Highly efficient removal of metal ion pollutants, such as toxic and nuclear waste-related metal ions, remains a serious task from the biological and environmental standpoint because of their harmful effects on human health and the environment. Recently, highly porous metal–organic frameworks (MOFs), with excellent chemical stability and abundant functional groups, have represented a new addition to the area of capturing various types of hazardous metal ion pollutants. This review focuses on recent progress in reported MOFs and MOF-based composites as superior adsorbents for the efficient removal of toxic and nuclear waste-related metal ions. Aspects related to the interaction mechanisms between metal ions and MOF-based materials are systematically summarized, including macroscopic batch experiments, microscopic spectroscopy analysis, and theoretical calculations. The adsorption properties of various MOF-based materials are assessed and compared with those of other widely used adsorbents. Finally, we propose our personal insights into future research opportunities and challenges in the hope of stimulating more researchers to engage in this new field of MOF-based materials for environmental pollution management.

Metal–organic framework-based materials: superior adsorbents for the capture of toxic and radioactive metal ions

Arsenic, cadmium, lead, and mercury are toxic elements that are almost ubiquitously present at low levels in the environment because of anthropogenic influences. Dietary intake of plant-derived food represents a major fraction of potentially health-threatening human exposure, especially to arsenic and cadmium. In the interest of better food safety, it is important to reduce toxic element accumulation in crops. A molecular understanding of the pathways responsible for this accumulation can enable the development of crop varieties with strongly reduced concentrations of toxic elements in their edible parts. Such understanding is rapidly progressing for arsenic and cadmium but is in its infancy for lead and mercury. Basic discoveries have been made in Arabidopsis, rice, and other models, and most advances in crops have been made in rice. Proteins mediating the uptake of arsenic and cadmium have been identified, and the speciation and biotransformations of arsenic are now understood. Factors controlling the efficiency of root-to-shoot translocation and the partitioning of toxic elements through the rice node have also been identified.

Toxic Heavy Metal and Metalloid Accumulation in Crop Plants and Foods

Multiple functions of p21 in cell cycle, apoptosis and transcriptional regulation after DNA damage.

Arsenic-induced oxidative stress and its reversibility

Transition metal ions are key elements of various biological processes ranging from oxygen formation to hypoxia sensing, and therefore, their homeostasis is maintained within strict limits through tightly regulated mechanisms of uptake, storage and secretion. The breakdown of metal ion homeostasis can lead to an uncontrolled formation of reactive oxygen species, ROS (via the Fenton reaction, which produces hydroxyl radicals), and reactive nitrogen species, RNS, which may cause oxidative damage to biological macromolecules such as DNA, proteins and lipids. An imbalance between the formation of free radicals and their elimination by antioxidant defense systems is termed oxidative stress. Most vulnerable to free radical attack is the cell membrane which may undergo enhanced lipid peroxidation, finally producing mutagenic and carcinogenic malondialdehyde and 4-hydroxynonenal and other exocyclic DNA adducts. While redox-active iron (Fe) and copper (Cu) undergo redox-cycling reactions, for a second group of redox-inactive metals such as arsenic (As) and cadmium (Cd), the primary route for their toxicity is depletion of glutathione and bonding to sulfhydryl groups of proteins. While arsenic is known to bind directly to critical thiols, other mechanisms, involving formation of hydrogen peroxide under physiological conditions, have been proposed. Redox-inert zinc (Zn) is the most abundant metal in the brain and an essential component of numerous proteins involved in biological defense mechanisms against oxidative stress. The depletion of zinc may enhance DNA damage by impairing DNA repair mechanisms. Intoxication of an organism by arsenic and cadmium may lead to metabolic disturbances of redox-active copper and iron, with the occurrence of oxidative stress induced by the enhanced formation of ROS/RNS. Oxidative stress occurs when excessive formation of ROS overwhelms the antioxidant defense system, as is maintained by antioxidants such as ascorbic acid, alpha-tocopherol, glutathione (GSH), carotenoids, flavonoids and antioxidant enzymes which include SOD, catalase and glutathione peroxidase. This review summarizes current views regarding the role of redox-active/inactive metal-induced formation of ROS, and modifications to biomolecules in human disease such as cancer, cardiovascular disease, metabolic disease, Alzheimer's disease, Parkinson's disease, renal disease, blood disorders and other disease. The involvement of metals in DNA repair mechanisms, tumor suppressor functions and interference with signal transduction pathways are also discussed.

Redox- and non-redox-metal-induced formation of free radicals and their role in human disease.

Arsenic (As) is a toxic metalloid element that is present in air, water and soil. Inorganic arsenic tends to be more toxic than organic arsenic. Examples of methylated organic arsenicals include monomethylarsonic acid [MMA(V)] and dimethylarsinic acid [DMA(V)]. Reactive oxygen species (ROS)-mediated oxidative damage is a common denominator in arsenic pathogenesis. In addition, arsenic induces morphological changes in the integrity of mitochondria. Cascade mechanisms of free radical formation derived from the superoxide radical, combined with glutathione-depleting agents, increase the sensitivity of cells to arsenic toxicity. When both humans and animals are exposed to arsenic, they experience an increased formation of ROS/RNS, including peroxyl radicals (ROO•), the superoxide radical, singlet oxygen, hydroxyl radical (OH•) via the Fenton reaction, hydrogen peroxide, the dimethylarsenic radical, the dimethylarsenic peroxyl radical and/or oxidant-induced DNA damage. Arsenic induces the formation of oxidized lipids which in turn generate several bioactive molecules (ROS, peroxides and isoprostanes), of which aldehydes [malondialdehyde (MDA) and 4-hydroxy-nonenal (HNE)] are the major end products. This review discusses aspects of chronic and acute exposures of arsenic in the etiology of cancer, cardiovascular disease (hypertension and atherosclerosis), neurological disorders, gastrointestinal disturbances, liver disease and renal disease, reproductive health effects, dermal changes and other health disorders. The role of antioxidant defence systems against arsenic toxicity is also discussed. Consideration is given to the role of vitamin C (ascorbic acid), vitamin E (α-tocopherol), curcumin, glutathione and antioxidant enzymes such as superoxide dismutase, catalase and glutathione peroxidase in their protective roles against arsenic-induced oxidative stress.

/pdf/arsenic-toxicity-oxidative-stress-and-human-disease-2lp5eu82d7.pdf

Arsenic: toxicity, oxidative stress and human disease.

The purpose of the study was to analyse and update consumers’ changing preferences in the choice of citrus fruit juices and to evaluate the sensory and physicochemical characteristics of two kinds of juices: juice squeezed from raw fruit and a commercial juice indicated by respondents as best matching their preferences. The survey was conducted in the form of an online survey posted on app.ankieteo.pl. The survey was also sent via a link through social networks. A total of 862 people took part in the survey. Consumers are most likely to consume juices one to three times a week (28.3%). Orange juice was the most popular among respondents (52.4%). The main factors influencing decisions to purchase citrus fruit juices are the type of fruit from which the juice was made, the vitamin content and the product’s price. In choosing juices, respondents were also guided by favourable health qualities and the presence of minerals. From the physicochemical determinations of orange juices obtained from a juicer and squeezer and commercial juice “O”, it was found that the quality of commercial orange juice indicated by consumers in the survey is comparable to juices made with a squeezer or a juice.

https://www.mdpi.com/2076-3417/13/2/765/pdf?version=1672916376

Quality Assessment of Natural Juices and Consumer Preferences in the Range of Citrus Fruit Juices

The ability of humus substances to form stable complexes with inorganic and organic soil constituents plays a vital role in the generation of environmental pollution, migration, and pollutants transformation. This paper deals with the study of the sorption of metallic elements (Al, Ca, Cu, Fe, K, Mn, Mg, Zn) in Andosols, Cambisols, and Planosols on Slovak soil types based on the detection of the quality and quantity of humus substances and soil textural properties. Five soil profiles from two areas in the central part of the Western Carpathians on volcanic rocks in Slovakia were investigated. HS values increased with Al, Ca, Cu, Fe, K, and Mg. Fe, Al, Ca, Mg, K, Mn, Cu, and Zn increased with the FA fraction. Al, Ca, Fe, K, and Mg were increasing with increasing HA values. In the HA fraction, a very tight relationship was among K and Fe contents (r = 0.902). In the FA fraction, we found with increasing Cu content, Ca content also increased (r = 0.959). The HS values were positively correlated with the silt and negatively correlated with the clay and the sand fraction. Only the elements Mn and Zn in Planosol were below the detection limit. High concentrations of metallic elements were in Andosol.

/pdf/the-distribution-of-metallic-elements-among-humus-substances-m6alm90m.pdf

The Distribution of Metallic Elements among Humus Substances in Soil from Volcanic Rocks

DEVELOPING HABITS AND SKILLS IN THE EDUCATIONAL PROCESS IN TERMS OF COMPLIANCE WITH THE WORK SAFETY PRINCIPLES 

Developing habits and skills in the educational process in terms of compliance with the work safety principles

The study points to the fact that chemistry is one of the fundamental and cross-cutting natural, technical and technological science fields. Therefore, the use of the term chemistry cannot be avoided. It is intended for users of chemistry terminology in technoeducation and points out its complexity and specificity. Furthermore, given the high dynamics in the field of nomenclature of chemistry and the number of terminological changes, it emphasizes the need to apply a critical approach, which illustrates the specific use of incorrect chemical terms. The study highlights that correct terminology in chemistry is both challenging and very important.

Melánia Feszterová

Papers

Arsenic: toxicity, oxidative stress and human disease.

Quality Assessment of Natural Juices and Consumer Preferences in the Range of Citrus Fruit Juices

The Distribution of Metallic Elements among Humus Substances in Soil from Volcanic Rocks

Developing habits and skills in the educational process in terms of compliance with the work safety principles

Complexity and specificness of chemical terminology