Toxicity of heavy metals in plants and animals and their uptake by magnetic iron oxide nanoparticles

State-of-the-art OMICS strategies against toxic effects of heavy metals in plants: A review

Environmental pollution of heavy metals (HMs), mainly due to anthropogenic activities, has received growing attention in recent decades. HMs, especially the non-essential carcinogenic ones, including chromium (Cr), cadmium (Cd), mercury (Hg), aluminum (Al), lead (Pb), and arsenic (As), have appeared as the most significant air, water, and soil pollutants, which adversely affect the quantity, quality, and security of plant-based food all over the world. Plants exposed to HMs could experience significant decline in growth and yield. To avoid or tolerate the toxic effects of HMs, plants have developed complicated defense mechanisms, including absorption and accumulation of HMs in cell organelles, immobilization by forming complexes with organic chelates, extraction by using numerous transporters, ion channels, signalling cascades, and transcription elements, among others. OMICS strategies have developed significantly to understand the mechanisms of plant transcriptomics, genomics, proteomics, metabolomics, and ionomics to counter HM-mediated stress stimuli. These strategies have been considered to be reliable and feasible for investigating the roles of genomics (genomes), transcriptomic (coding), mRNA transcripts (non-coding), metabolomics (metabolites), and ionomics (metal ions) to enhance stress resistance or tolerance in plants. The recent developments in the mechanistic understandings of the HMs-plant interaction in terms of their absorption, translocation, and toxicity invasions at the molecular and cellular levels, as well as plants' response and adaptation strategies against these stressors, are summarized in the present review. Transcriptomics, genomics, metabolomics, proteomics, and ionomics for plants against HMs toxicities are reviewed, while challenges and future recommendations are also discussed.

Environmental health and risk assessment metrics with special mention to biotransfer, bioaccumulation and biomagnification of environmental pollutants

The environment pollutants, which are landed up in environment because of human activities like urbanization, mining and industrializations, affects human health, plants and animals. The living organisms present in environment are constantly affected by the toxic pollutants through direct contact or bioaccumulation of chemicals from the environment. The toxic and hazardous pollutants are easily transferred to different environmental matrices like land, air and water bodies such as surface and ground waters. This comprehensive review deeply discusses the routes and causes of different environmental pollutants along with their toxicity, impact, occurrences and fate in the environment. Environment health and risk assessment tools that are used to evaluate the harmfulness, exposure of living organisms to pollutants and the amount of pollutant accumulated are explained with help of bio-kinetic models. Biotransfer, toxicity factor, biomagnification and bioaccumulation of different pollutants in the air, water and marine ecosystems are critically addressed. Thus, the presented survey would be collection of correlations those addresses the factors involved in assessing the environmental health and risk impacts of distinct environmental pollutants.

Plants and rhizospheric environment: Affected by zinc oxide nanoparticles (ZnO NPs). A review

Nowadays, there are many critical concerns in the agricultural sector, including reduced productivity of plants due to various environmental factors. Hence, a continuous innovation of existing technologies is necessary. Among the available technologies for sustainable agriculture, nanotechnology is one of the more promising technologies and has a great scope for development in agriculture. Zinc oxide nanoparticles (ZnO NPs) have attracted much attention due to their good properties and can be put into agriculture as nano-fertilizers, nano-growth regulators and nano-pesticides, although much remains to be explored about their mechanisms. Here, we review the literature on the interaction of ZnO NPs with plants through (i) uptake and transport pathways of ZnO NPs in plants. (ii) The mechanisms involved in improving growth, development and resistance. (iii) their effects on the rhizospheric environment. (iv) The toxic effects and mechanisms in plants. Our major conclusions are as follows: (1) they can be absorbed by the plant through the roots and leaves, with subsequent transformation. (2) moderate application can promote plant growth and mitigate stress, while excessive application can produce toxic effects. (3) the effects of them on the rhizospheric environment cannot be ignored. This study may provide a reference for the safe and effective use of ZnO NPs in agricultural production.

HPLC Analysis and the Antioxidant and Preventive Actions of Opuntia stricta Juice Extract against Hepato-Nephrotoxicity and Testicular Injury Induced by Cadmium Exposure

Opuntia stricta is a rich source of phenolic compounds. This species generally has strong antioxidant activities in vitro and in vivo. This study aimed to analyze the antioxidant properties of phenolic compounds isolated from Opuntia stricta, including its radical scavenging activities and preventive action against Cd-induced oxidative stress in rats. To assess the protection of prickly pear juice extract (PPJE) against Cd-induced hepato-nephrotoxicity and testicular damage, male albino rats received PPJE (250 mg kg−1) and/or Cd (1 mg kg−1) by oral administration and injection, respectively, for five consecutive weeks. The preventive action of PPJE was estimated using biochemical markers of kidney and liver tissues, antioxidant status, and histological examinations. In the present study, the lipid peroxidation, protein carbonyls, antioxidant status, and metallothionein levels were determined in different tissues. The chromatographic analysis indicated that PPJE extract is very rich in phenolic compounds such as verbascoside, catechin hydrate, and oleuropein. Our results showed that PPJE-treated rats had significantly (p < 0.05) decreased Cd levels in liver and kidney tissues. In addition, the administration of PPJE induced a significant (p < 0.05) decrease in lipid peroxidation of 30.5, 54.54, and 40.8 in the liver, kidney, and testicle, respectively, and an increase in antioxidant status in these tissues. Additionally, PPJE showed a strong ability to protect renal, hepatic, and testicular architectures against Cd exposure. This study revealed that PPJE protects against the toxic effects of Cd, possibly through its free radical scavenging and antioxidant activities.

Synergistic effects of Cd-loving Bacillus sp. N3 and iron oxides on immobilizing Cd and reducing wheat uptake of Cd

Iron oxides and microorganisms are important soil components that profoundly affect the transformation and bioavailability of heavy metals in soils. Here, batch and pot experiments were conducted to investigate the immobilization mechanisms of Cd by Cd-loving Bacillus sp. N3 and ferrihydrite (Fh) as well as their impacts on Cd uptake by wheat and bacterial community composition in wheat rhizospheric soil. The results showed that the combination of strain N3 with Fh could immobilize more Cd compared to strain N3 and Fh, respectively. Furthermore, strain N3 facilitated Cd retention on Fh, which synergistically reduced the concentration of DTPA extracted Cd in the soil and decreased Cd content (57.1%) in wheat grains. Moreover, inoculation with strain N3 increased the complexity of the co-occurrence network of the bacterial community in rhizospheric soil, and the abundance of beneficial bacteria with multipel functions including heavy metal immobilization, dissimilatory iron reduction, and plant growth promotion. Overall, this study demonstrated the enrichment of strain N3 and iron oxides, together with increased soil pH, synergistically immobilized soil Cd, which strongly suggested inoculation with Cd-loving strains could be a promising approach to immobilize Cd and reduce wheat uptake of Cd, particular for soils rich in iron oxides.

Removal of Cr(VI) from Wastewater Using Graphene Oxide Chitosan Microspheres Modified with α-FeO(OH)

Graphene oxide and chitosan microspheres modified with α−FeO(OH) (α−FeO(OH)/GOCS) are prepared and utilized to investigate the performance and mechanism for Cr(VI) removal from aqueous solutions and the possibility of Fe secondary pollution. Batch experiments were carried out to identify the effects of pH, mass, and volume ratio (m/v), coexisting ions, time (t), temperature (T), and Cr(VI) initial concentration (C0) on Cr(VI) removal, and to evaluate adsorption kinetics, equilibrium isotherm, and thermodynamics, as well as the possibility of Fe secondary pollution. The results showed that Cr(VI) adsorption increased with C0, t, and T but decreased with increasing pH and m/v. Coexisting ions inhibited Cr(VI) adsorption, and this inhibition increased with increasing concentration. The influence degrees of anions and cations on the Cr(VI) adsorption in descending order were SO42− > PO42− > NO3− > Cl− and Ca2+ > Mg2+ > Mn2+, respectively. The equilibrium adsorption capacity of Cr(VI) was the highest at 24.16 mg/g, and the removal rate was 97.69% under pH = 3, m/v = 1.0 g/L, T = 298.15 K, and C0 = 25 mg/L. Cr(VI) adsorption was well fitted to a pseudo-second-order kinetic model and was spontaneous and endothermic. The best fit of Cr(VI) adsorption with the Langmuir and Sips models indicated that it was a monolayer and heterogeneous adsorption. The fitted maximum adsorption capacity was 63.19 mg/g using the Sips model under 308.15 K. Cr(VI) removal mainly included electrostatic attraction between Cr(VI) oxyanions with surface Fe−OH2+, and the adsorbed Cr(VI) was partially reduced to Cr(III) and then precipitated on the surface. In addition, there was no Fe secondary pollution during Cr(VI) adsorption.

Chemical Nature of Metals and Metal-Based Materials in Inactivation of Viruses

In response to the enormous threat to human survival and development caused by the large number of viruses, it is necessary to strengthen the defense against and elimination of viruses. Metallic materials have been used against viruses for thousands of years due to their broad-spectrum antiviral properties, wide sources and excellent physicochemical properties; in particular, metal nanoparticles have advanced biomedical research. However, researchers in different fields hold dissimilar views on the antiviral mechanisms, which has slowed down the antiviral application of metal nanoparticles. As such, this review begins with an exhaustive compilation of previously published work on the antiviral capacity of metal nanoparticles and other materials. Afterwards, the discussion is centered on the antiviral mechanisms of metal nanoparticles at the biological and physicochemical levels. Emphasis is placed on the fact that the strong reducibility of metal nanoparticles may be the main reason for their efficient inactivation of viruses. We hope that this review will benefit the promotion of metal nanoparticles in the antiviral field and expedite the construction of a barrier between humans and viruses.

A review on bioremediation approach for heavy metal detoxification and accumulation in plants

Nowadays, the accumulation of toxic heavy metals in soil and water streams is considered a serious environmental problem that causes various harmful effects on plants and animals. Phytoremediation is an effective, green, and economical bioremediation approach by which the harmful heavy metals in the contaminated ecosystem can be detoxified and accumulated in the plant. Hyperaccumulators exude molecules called transporters that carry and translocate the heavy metals present in the soil to different plant parts. The hyperaccumulator plant genes can confine higher concentrations of toxic heavy metals in their tissues. The efficiency of phytoremediation relies on various parameters such as soil properties (pH and soil type), organic matters in soil, heavy metal type, nature of rhizosphere, characteristics of rhizosphere microflora, etc. The present review comprehensively discusses the toxicity effect of heavy metals on the environment and different phytoremediation mechanisms for the transport and accumulation of heavy metals from polluted soil. This review gave comprehensive insights into plants tolerance for the higher heavy metal concentration their responses for heavy metal accumulation and the different mechanisms involved for heavy metal tolerance. The current status and the characteristic features that need to be improved in the phytoremediation process are also reviewed in detail.

Occurrence of Potentially Toxic Elements in Bottled Drinking Water-Carcinogenic and Non-Carcinogenic Risks Assessment in Adults via Ingestion

The presence of potentially toxic elements in drinking water can be dangerous for human health because of their bioaccumulation and toxicity, which is a huge concern for many researchers. In the case of bottled water, the exposure to toxic elements is achieved, especially by ingestion, leading to disorders of important functions of the human body. The aim of this study was the detection of some potentially toxic elements, from 50 samples of bottled drinking water, available on the Romanian market. Based on obtained concentrations, an assessment of the carcinogenic and non-carcinogenic health risk was performed. The concentrations of potentially toxic elements analyzed were below the maximum allowable limits, for all contaminants, excluding Pb and Fe. Moreover, the results of total risk via ingestion, showed that 30% of samples had an Hazard Quotient (HQ) < 1, and 70% had an HQ > 1; which implies a potential risk following the consumption of those samples. Concerning total cancer risk, 28% of the samples are in the acceptable level, while 72% of the samples are considered harmful and can lead to a type of cancer after repeated exposure. The study concluded that long term use of bottled water of poor quality may pose a hazard to human health; it is helpful for inhabitants to avoid ingestion of contaminated water.

Overview of the Influence of Silver, Gold, and Titanium Nanoparticles on the Physical Properties of PEDOT:PSS-Coated Cotton Fabrics

Metallic nanoparticles have been of interest to scientists, and they are now widely used in biomedical and engineering applications. The importance, categorization, and characterization of silver nanoparticles, gold nanoparticles, and titanium nanoparticles have been discussed. Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) is the most practical and reliable conductive polymer used in the manufacturing of conductive textiles. The effects of metallic nanoparticles on the performance of PEDOT:PSS thin films are discussed. The results indicated that the properties of PEDOT:PSS significantly depended on the synthesis technique, doping, post-treatment, and composite material. Further, electronic textiles known as smart textiles have recently gained popularity, and they offer a wide range of applications. This review provides an overview of the effects of nanoparticles on the physical properties of PEDOT:PSS-coated cotton fabrics.

The Butterfly Effect: Mild Soil Pollution with Heavy Metals Elicits Major Biological Consequences in Cobalt-Sensitized Broad Bean Model Plants

Among the heavy metals (HMs), only cobalt induces a polymorphic response in Vicia faba plants, manifesting as chlorophyll morphoses and a ‘break-through’ effect resulting in the elevated accumulation of other HMs, which makes Co-pretreated broad bean plants an attractive model for investigating soil pollution by HMs. In this study, Co-sensitized V. faba plants were used to evaluate the long-term effect of residual industrial pollution by examining biochemical (H₂O₂, ascorbic acid, malondialdehyde, free proline, flavonoid, polyphenols, chlorophylls, carotenoids, superoxide dismutase) and molecular (conserved DNA-derived polymorphism and transcript-derived polymorphic fragments) markers after long-term exposure. HM-polluted soil induced a significantly higher frequency of chlorophyll morphoses and lower levels of nonenzymatic antioxidants in Co-pretreated V. faba plants. Both molecular markers effectively differentiated plants from polluted and control soils into distinct clusters, showing that HMs in mildly polluted soil are capable of inducing changes in DNA coding regions. These findings illustrate that strong background abiotic stressors (pretreatment with Co) can aid investigations of mild stressors (slight levels of soil pollution) by complementing each other in antioxidant content reduction and induction of DNA changes.

Ecological and Human Health Risk Assessment of Heavy Metals in Cultured Shrimp and Aquaculture Sludge

Shrimp is one of the major export products in South Asian countries and also an eminent source of nutrition for humans. Hence, any negative effect of this industry may affect not only the country’s economy but also human health. Therefore, in this study, we aimed to assess heavy metal contamination and associated human health risks in cultured shrimp (Penaeus monodon) and aquaculture sludge collected from three shrimp farms of the Cox’s Bazar district, Bangladesh. The results showed that among the eight metals studied, Pb (17.75 ± 1.5 mg/kg) and Cu (9.43 ± 2.8 mg/kg) levels in all shrimp samples were higher than the recommended limit, whereas the concentrations of Cd (0.09 ± 0.03 mg/kg), Mn (4.83 ± 2.2 mg/kg), As (0.04 ± 0.02 mg/kg), Hg (0.02 ± 0.006 mg/kg), Zn (18.89 ± 2.9 mg/kg) and Cr (0.69 ± 0.6 mg/kg) were within the permissible level. The concentrations of Mn (1043.37 ± 59.8 mg/kg), Cr (30.38 ± 2.1 mg/kg), Zn (74.72 ± 1.13 mg/kg) and Cu (31.14 ± 1.4 mg/kg) in the sludge of all farms were higher than the recommended limit, whereas the concentrations of Pb (20.23 ± 1.9 mg/kg), Cd (0.09 ± 0.2 mg/kg), As (0.44 ± 0.34 mg/kg) and Hg (0.08 ± 0.02 mg/kg) in all sludge samples were lower than the threshold limits. However, the estimated daily intake (EDI), targeted hazard quotient (THQ) and hazard index (HI) assessed for potential human health risk implications suggested that Pb and Cr may pose non-carcinogenic health effects, although carcinogenic risks (CR) values were acceptable for consumers. However, the pollution load index (PLI) of the studied area was below 1, which indicates low deterioration of the area. Geoaccumulation index (Igeo) and contamination factor (CF) analyses revealed that study area is unpolluted and sludge is enriched with metals in the following order: Mn > Zn > Cu > Cr > Cd > Hg > Pb > As.

Brevundimonas diminuta isolated from mines polluted soil immobilized cadmium (Cd2+) and zinc (Zn2+) through calcium carbonate precipitation: Microscopic and spectroscopic investigations

The toxic metal(loid)s TMs resistant bacterium Brevundimonas diminuta was isolated for the first time from mines polluted soil in Fengxian, China, and assessed for its potential for Cd and Zn precipitation in Cd and Zn co-contaminated aqueous solution at various Cd and Zn levels (20, 40, 80, 160, and 200 mg L^-1), pH values (5, 6, 7, 8, and 9), and temperatures (20, 25, 30, and 35 °C). B. diminuta showed a high resistance to both Cd and Zn and was able to precipitate up to 99.2 and 99.7% of dissolved Cd and Zn respectively, at a pH of 7 and temperature of 30 °C. B. diminuta reduced the dissolved concentrations of Cd and Zn below the threshold levels in water. The 3D-EEM analysis revealed the presence of extracellular polymeric substances (EPS) such as tryptophan indicating bacterial growth under Cd/Zn stress. FTIR showed polysaccharides, CO₃^2-, CaCO₃, PO₄^3-, and proteins, which may enhance bacterial growth and metal precipitation. SEM-EDS confirmed the leaf-like and granular shape of the biological precipitation and reduction in the percent weight of TMs, which promoted the adhesion/adsorption of Cd²⁺, Zn²⁺, and Ca²⁺. Moreover, XRD analysis confirmed the precipitation of Cd, Zn, and Ca in the form of CdCO₃/Cd₃(PO₄)₂, ZnCO₃/ZnHPO₄/Zn₂(OH)PO₄/Zn₃(PO₄)₂, and CaCO₃/Ca₅(PO₃)₄OH, respectively. These findings indicate that Brevundimonas diminuta can be used for the bioremediation of TMs-contaminated aquatic environments.

A Survey on Nanotechnology-Based Bioremediation of Wastewater

Rainwater discharge and human impacts produce wastewater, which is a contaminated type of water. Sediments also discharge phosphate into the water column when there is a lack of dissolved oxygen in the water. Through the manufacturing of environmentally benign nanoparticles, nanotechnology may reduce the amount of money spent by enterprises to remediate such contaminants. Because of their improved physiological, biochemical, and biomechanical qualities, nanoparticles are getting prominence. The importance of the global wastewater dilemma is discussed in this survey. The use of nanomaterials in heavy metal remediation (HMR) and wastewater treatment is covered in this survey. This paper also discusses the benefits of nanotechnology over traditional approaches in certain fields. This survey aims to gather together many recent studies on nanoparticle production and their benefits as adsorbents in the remediation of wastewater which have been done so far. The promising role of nanotechnology in wastewater remediation is surveyed in this research, which also discusses recent developments in nanotechnology-mediated remediation methods. This survey examines the vital potential of nanotechnology in wastewater treatment, as well as recent breakthroughs in nanotechnology-mediated treatment systems.

Assessment of Potentially Toxic Elements and Associated Health Risk in Bottled Drinking Water for Babies

Potentially toxic elements are chemical pollutants which are dangerous to human health, especially for babies and children. Because their presence has been detected in baby food and baby drinking water, exposure to these elements is mainly due to ingestion. For this reason, the main objective of this study was quantification of 12 potentially toxic elements, including Ba, Co, Cu, Zn, Mn, Ni, Li, Fe, Pb, Cd, Cr, Sb, by ICP–MS, from 19 samples of bottled baby water. Based on the levels obtained, a health risk assessment was performed of the risk caused by their consumption, as well as an analysis of the quality of the samples. Excep iron, the values obtained for all other metals were below the limits imposed by the legislation in force. The risk analysis shows that Hazard index values were included in Risk Class 1, with a very low hazard level. The order of Cancer Risk values is as follows, Cd < Cr < Ni < Pb. As a general conclusion, we can say that the samples can be intended for consumption by children and infants.

Removal of metal ions using a new magnetic chitosan nano-bio-adsorbent; A powerful approach in water treatment

In this study, a magnetic chitosan/Al₂O₃/Fe₃O₄ (M-Cs) nanocomposite was developed by ethylenediaminetetraacetic acid (EDTA) functionalization to enhance its adsorption behavior for the removal of Cd(II), Cu(II) and Zn(II) metal ions from aqueous solution. The results revealed that the EDTA functionalization of M-Cs increased its adsorption capacity ~9.1, ~5.6 and ~14.3 times toward Cu, Cd and Zn ions. The maximum adsorption capacity followed the order of Cd(II) > Cu(II) > Zn(II) and the maximum adsorption efficiency was achieved at pH of 5.3 with the removal percentage of 99.98, 93.69 and 83.81 %, respectively, for the removal of Cu, Cd and Zn ions. The metal ions adsorption kinetic obeyed pseudo-second-order equation and the Langmuir isothermal was found the most fitted model for their adsorption isothermal experimental data. In addition, the thermodynamic study illustrated that the adsorption process was exothermic and spontaneous in nature.

Gamma radiation-induced synthesis of a novel chitosan/silver/Mn-Mg ferrite nanocomposite and its impact on cadmium accumulation and translocation in brassica plant growth

Herein, a novel chitosan/silver/Mn_0.5Mg_0.5Fe₂O₄ (Cs/Ag/MnMgFe₂O₄) nanocomposite was synthesized with gamma irradiation assistant. The prepared Cs/Ag/MnMgFe₂O₄ nanocomposite was characterized via EDX, XRD, SEM, UV-vis spectroscopy. To evaluate the effects of soak low and high-dose nanocomposite on physiological parameters, photosynthetic pigments, antioxidant and non-antioxidant enzymes of cabbage under Cd stress, a factorial experiment was conducted based on CRD with five replications. The Cd stress decreased the morphological characteristics and photosynthetic pigments while increasing cabbage's antioxidant and non-antioxidant enzymes. The application of low and high-dose of nanocomposite decreased Cd content in leaves by about 42.86%, 60.48%, and the root by approximately 18.72%, 28.72%, respectively, and translocation factors and tolerance index, H₂O₂, O₂, and malondialdehyde. In contrast, the application of high of the nanocomposite increased the values of SPAD chlorophyll about 27.50%, stomatal conductance about 87.18%, net photosynthetic rate about 44.90%, intercellular CO₂ concentration about 32.00%, and transpiration rate about 85.20%, as compared to Cd stress. Furthermore, the application of low and high-dose Cs/Ag/MnMgFe₂O₄ nanocomposite enhances the antioxidant and non-antioxidant enzymes of the cabbage plant compared to Cd stress. Generally, it was conducted that Cs/Ag/MnMgFe₂O₄ nanocomposite can be used as a proper tool for increasing cabbage plants under Cd stress.

Bio-efficacy of iron and zinc fortified wheat flour along with bio-assessment of its hepatic and renal toxic potential

Abstract Study was planned to assess the bio-efficiency along with toxicity of iron and zinc fortified whole wheat flour in Sprague dawley albino rats. Whole wheat flour was fortified with different dosage of sodium iron EDTA (NaFeEDTA), ferrous sulphate (FeSO4), zinc oxide (ZnO) and zinc sulphate (ZnSO4). The rats (n=3) in each group were fed on fortified wheat flour for 2 months. Liver biomarkers including alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate aminotransferase (AST) and bilirubin were recorded from serum samples. Increased concentration of ZnSO4 affected the liver biomarkers to be highest among all whereas, bilirubin levels were less than the rats fed on control diet. The above mentioned fortificants have negligible effect on renal biomarkers including creatinine and urea. Moreover, hematological parameters were also checked and reportedly, sodium iron EDTA fed rats presented highest amount of hemoglobin, iron and total iron binding capacity. Highest zinc level was observed in rats fed on whole wheat flour fortified with 60mg/Kg Zinc oxide. Microscopic observation of liver tissue depicted that rats fed on iron and zinc fortified wheat flour have more toxic effects whereas, histopathology presentation of kidney tissue has least toxic impact. It has been concluded that mandatory fortification of wheat flour with iron and zinc may cause increased serum biomarkers along with toxicity of vital organs like liver, hence fraction of wheat flour may be fortified to fulfill the requirements of deprived and vulnerable group.

Snail slime-based gold nanoparticles: An interesting potential ingredient in cosmetics as an antioxidant, sunscreen, and tyrosinase inhibitor

Due to their properties, snail slime-based products have been appreciated and used worldwide. So, as an alternative and innovative use of snail slime, it was adopted to induce gold nanoparticles' formation, conferring them interesting properties. By a simple, one-pot, and eco-friendly approach, 14 ± 6 nm wide hybrid gold nanoparticles, having an inorganic metallic core decorated by the slime's main components, were obtained. Among their several properties, their antioxidant and tyrosinase inhibition activity were investigated through the DPPH and ABTS and the tyrosinase assays, respectively. After assessing their non-cytotoxicity in our previous work, the results revealed positive responses, enabling their use as a potential novel multifunctional ingredient in cosmetics. Interestingly, the gold nanoparticle photostability, investigated by means of a solar simulator lamp, suggests using them in commercial cosmetic sunscreen products as a potential alternative to the commonly used inorganic sunscreen ingredients. The theoretical Sun Protection Factor was evaluated, obtaining values in the range 0-12. The proposed environmentally friendly and cost-effective protocol for nanoparticle synthesis, following the principles of Green Chemistry, opens a hugely attractive space toward the study of snail slime-based gold nanoparticles as a potential multipurpose platform in cosmetics.

A Review on Biosensors and Nanosensors Application in Agroecosystems

Previous decades have witnessed a lot of challenges that have provoked a dire need of ensuring global food security. The process of augmenting food production has made the agricultural ecosystems to face a lot of challenges like the persistence of residual particles of different pesticides, accretion of heavy metals, and contamination with toxic elemental particles which have negatively influenced the agricultural environment. The entry of such toxic elements into the human body via agricultural products engenders numerous health effects such as nerve and bone marrow disorders, metabolic disorders, infertility, disruption of biological functions at the cellular level, and respiratory and immunological diseases. The exigency for monitoring the agroecosystems can be appreciated by contemplating the reported 220,000 annual deaths due to toxic effects of residual pesticidal particles. The present practices employed for monitoring agroecosystems rely on techniques like gas chromatography, high-performance liquid chromatography, mass spectroscopy, etc. which have multiple constraints, being expensive, tedious with cumbersome protocol, demanding sophisticated appliances along with skilled personnel. The past couple of decades have witnessed a great expansion of the science of nanotechnology and this development has largely facilitated the development of modest, quick, and economically viable bio and nanosensors for detecting different entities contaminating the natural agroecosystems with an advantage of being innocuous to human health. The growth of nanotechnology has offered rapid development of bio and nanosensors for the detection of several composites which range from several metal ions, proteins, pesticides, to the detection of complete microorganisms. Therefore, the present review focuses on different bio and nanosensors employed for monitoring agricultural ecosystems and also trying to highlight the factor affecting their implementation from proof-of-concept to the commercialization stage.

Thiol-methyl-modified magnetic microspheres for effective cadmium (II) removal from polluted water

For effective removal of cadmium (II) (Cd(II)) from polluted water, a magnetic adsorbent of Fe₃O₄@SiO₂ core-shell microspheres modified with methyl-protected thiol groups (Fe₃O₄@SiO₂-SH-Protected) was synthesized and characterized by scanning electron, transmission electron, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopies, as well as X-ray diffraction, Raman spectroscopy, and magnetic measurements. Characterization results showed that thiol groups on the surface of Fe₃O₄@SiO₂ material were protected to avoid disulfide formation. Batch adsorption experiments were conducted by varying the contact time, initial pH, solid-liquid ratio, temperature, Cd(II) concentrations, and interfering cations. Fe₃O₄@SiO₂-SH-Protected material exhibited much higher adsorption capacity than Unprotected forms and other adsorbents due to methyl group protection. The maximum adsorption capacity calculated from the Langmuir fitting was 27.5 mg·g^-1 (pH 7, 25 °C), and the adsorption kinetics followed a pseudo-second-order model, and adsorption mainly dominated by film diffusion processes. Thermodynamic parameters indicated that the adsorption process was a spontaneous, endothermic, and positive entropic process. Cd(II)-loaded on the adsorbent was easily desorbed with 0.1 M HCl and the adsorbent stable in 0.1 M HCl for long times, showing good reusability and stability.

Ecofriendly remediation technologies for wastewater contaminated with heavy metals with special focus on using water hyacinth and black tea wastes: a review

Treatment of water contaminated with heavy metals is challenging. Heavy metals are non-degradable, persistent in the environment, have a high dispersion capacity by water, can bioaccumulate, and represent risks to human and environmental health. Conventional treatment methods have disadvantages; however, adsorption in biomass is a highly promising method with high efficiency and low cost that avoids many of the disadvantages of conventional methods. Black tea (BT) wastes and water hyacinth (WH) have attracted attention for their ability to remove heavy metals from wastewater. Utilizing these approaches can remove contaminants and effectively manage problematic invasive species and wastes. The conventional uses of BT and WH were efficient for removing heavy metals from wastewater. Due to the unique and distinct properties and advantages of biochar and nano-forms of biosorbents, the use of BT and WH in these forms is promising to achieve sustainable heavy metals removal from wastewater. However, more study is needed to confirm preliminary results.

The Levels of Mineral Elements and Toxic Metals in the Longissimus lumborum Muscle, Hair and Selected Organs of Red Deer (Cervus elaphus L.) in Poland

Simple Summary

The relationships between nutritive elements (Fe, Mn, Zn, Cu, Na, K, Ca and Mg) and toxic metals (Pb and Cd) can inform the assessment of health status of red deer, which are exposed to pollution in their natural environment. These elements in the longissimus lumborum muscle, hair and selected organs of red deer (Cervus elaphus L.) were analysed. The study revealed many significant correlations between the levels of elements and their high variability in individual tissues and organs. The accumulation of a specific metal in a tissue or organ can reduce its concentration in another matrix or promote increased content in another tissue or organ.

Abstract

The aim of the study was to analyse correlations and variability between the levels of mineral elements (Fe, Mn, Zn, Cu, Na, K, Ca and Mg) and toxic metals (Pb and Cd) in the longissimus lumborum muscle, hair and selected organs of red deer (Cervus elaphus L.). The levels of mineral elements were measured using atomic absorption spectroscopy (F-AAS). The levels of Pb and Cd were analysed by means of electrothermal atomic absorption spectroscopy (ET-AAS). Of all analysed microelements, the highest concentration (in g·kg⁻¹ of dry weight) was found for Fe in the liver. Considering all macroelements, the highest level was found for K in the longissimus lumborum muscle. Particularly remarkable was the high level of Pb in the muscle and hair of red deer. The level of Cd in the hair was four to five times lower than in other samples. The study revealed many significant correlations between the levels of certain elements in individual tissues and organs. There were significant correlations between Cu-Fe (r_xy = 0.650; p ≤ 0.01), Pb-Cu (r_xy = −0.863; p ≤ 0.01) and Cd-Ca (r_xy = −0.743; p ≤ 0.01) in testicles. For kidneys, a significant negative correlation was found for K and Na (r_xy = −0.779; p ≤ 0.01) and for Ca and Cd (r_xy = −0.695; p ≤ 0.01), and a positive correlation between Cu and Mn (r_xy = 0.693; p ≤ 0.01). In the liver, significant negative correlations were found between Ca-K (r_xy = −0.654; p ≤ 0.05), Cd-Fe (r_xy = −0.651; p ≤ 0.05) and Pb-Cu (r_xy = −0.627; p ≤ 0.05). In the muscle, only single significant correlations were found between Cd and Mn (r_xy = 0.648; p ≤ 0.05). The highest number of significant correlations were recorded for the hair, among others between Na-K (r_xy = 0.760) and Ca-Zn (r_xy = 0.709) at p ≤ 0.01. The study revealed high variability in the levels of mineral elements and selected toxic metals in tissues, organs and hair of red deer. Additionally, this research confirmed that the accumulation of a specific metal in a tissue or organ can reduce its concentration in another matrix or promote its increased content in another tissue or organ.