Bioavailability Of Zn Research Articles

Mobility, Speciation and Bioavailability of Zn and Pb in Artificially Polluted Soils by Magnetic Biochars from Siraitia Grosvenorii Residues

Mobility, Speciation and Bioavailability of Zn and Pb in Artificially Polluted Soils by Magnetic Biochars from Siraitia Grosvenorii Residues

Comparing the individual and combined effects of nano zinc and conventional zinc fertilization on growth, yield, phytochemical properties, antioxidant activity, and secoisolariciresinol diglucoside content in linseed

Zinc sulfate (ZnSO4), a conventional Zn fertilizer, is widely used due to its high solubility and ease of application. In contrast, nano Zn represents an innovative approach, utilizing nanoscale particles to enhance Zn bioavailability and uptake efficiency. This study compares these two Zn fertilizers regarding their impact on plant growth, yield, Zn uptake, and overall crop quality. In our study, we explored the potential of nano Zn and ZnSO4 by applying two different doses of each (100, 1000 ppm ZnO NP and 30, 50 kg ha−1 ZnSO4) both individually and in combination, to linseed accession. The results obtained showed the potential of nano Zn over conventional Zn fertilizer in terms of enhanced linseed growth and yield together with greater antioxidants enzyme, oil content, protein content, Zn accumulation, secoisolariciresinol diglucoside (SDG) content, and the accumulation of bioactive metabolites. Nanoscale ZnO (with particle size less than 100 nm) at a 1000 ppm concentration sped up growth, yield, increased SDG content, and antioxidant activity. However, when nano Zn (1000 ppm) was applied in combination with ZnSO4 (30 kg ha−1), it maximally enhanced plant fresh and dry weight, photosynthesis, and yield compared to their individual treatment. The combined application increased seed yield by 4.55 folds compared to the control. The treated plants were assessed for SDG content using liquid chromatography-mass spectrometry analysis (LC-MS), which showed maximum increase with 1000 ppm ZnO NP. SDG is a type of lignan known for their antioxidant properties and potential health benefits paving way for its pharmaceutical importance.

Geochemical Interaction and Bioavailability of Zinc in Soil Under Long‐Term Integrated Nutrient Management in Pearl Millet–Wheat System

ABSTRACTThe degree and severity of zinc (Zn) deficiency in soil reduced the agricultural yield and quality, thus encouraging malnutrition in humans worldwide. The study was hypothesized to increase the bioavailability and release of Zn in soil and Zn biofortification in wheat grains under integrated nutrient management (INM). The long‐term (54 years) experiment laid out in a split‐plot design comprising single (W) and dual (PW) applications of farmyard manure (FYM) (0, 5, 10, and 15 Mg ha−1) and nitrogen (0, 60, and 120 kg ha−1) was studied to understand the distribution of different Zn fractions in soil and their relationship to wheat grain yield and Zn uptake. A laboratory incubation study was performed on surface soils to evaluate the release kinetics of native Zn at field capacity. The different fractions of Zn in soil increased with increasing frequency and levels of FYM application. Residual Zn constituted the maximum proportion (89.03%) of total soil Zn. A high positive correlation (p < 0.01) of diethylenetriaminepentaacetic acid (DTPA)‐extractable Zn and total grain Zn content were observed with different Zn fractions. The release kinetics of native soil Zn increased up to 10 days and became almost constant, indicating the establishment of chemical equilibria between the soil solid and solution phase. Thus, long‐term INM ensured higher wheat production (6.08 Mg ha−1) and Zn biofortification (38.95 mg kg−1) to combat Zn malnutrition and achieve the United Nations’ sustainable development goals on “zero hunger” and “good health and well‐being.”

The five homologous CiaR-controlled Ccn sRNAs of Streptococcus pneumoniae modulate Zn-resistance.

Zinc is a vital transition metal for all bacteria; however, elevated intracellular free Zn levels can result in mis-metalation of Mn-dependent enzymes. For Mn-centric bacteria such as Streptococcus pneumoniae that primarily use Mn instead of Fe as an enzyme cofactor, Zn is particularly toxic at high concentrations. Here, we report our identification and characterization of the function of the five homologous, CiaRH-regulated Ccn sRNAs in controlling S. pneumoniae virulence and metal homeostasis. We show that deletion of all five ccn genes (ccnA, ccnB, ccnC, ccnD, and ccnE) from S. pneumoniae strains D39 (serotype 2) and TIGR4 (serotype 4) causes Zn hypersensitivity and an attenuation of virulence in a murine invasive pneumonia model. We provide evidence that bioavailable Zn disproportionately increases in S. pneumoniae strains lacking the five ccn genes. Consistent with a response to Zn intoxication or relatively high intracellular free Zn levels, expression of genes encoding the CzcD Zn exporter and the Mn-independent ribonucleotide reductase, NrdD-NrdG, were increased in the ΔccnABCDE mutant relative to its isogenic ccn+ parent strain. The growth inhibition by Zn that occurs as the result of loss of the ccn genes is rescued by supplementation with Mn or Oxyrase, a reagent that removes dissolved oxygen. Lastly, we found that the Zn-dependent growth inhibition of the ΔccnABCDE strain was not altered by deletion of sodA, whereas the ccn+ ΔsodA strain phenocopied the ΔccnABCDE strain. Overall, our results indicate that the Ccn sRNAs have a crucial role in preventing Zn intoxication in S. pneumoniae.

Effects of dietary calcium and microbial phytase on the bioavailability of two sources of zinc in broilers

ABSTRACT 1. The objective of this study was to test the effect of microbial phytase and calcium (Ca) levels on the Zn bioavailability depending on the Zn source. 2. A total of 144, one-day-old broilers received a diet containing 40 mg Zn/kg for 1 week. They were then assigned to one of the eight experimental treatments during 2 weeks. Diets contained 27 mg native Zn and were formulated according to a 2 × 2 × 2 factorial design with two added Zn sources (23 mg Zn/kg), sulphate (ZnSO4) or oxide (ZnO); two dietary Ca levels of either 6 (low) or 10 g/kg (moderate); and two microbial phytase levels, of either 0 or 750 phytase unit/kg. 3. Moderate Ca plus phytase improved body weight gain (BWG) and low Ca level without microbial phytase decreased tibia weight (Ca × Phy; p = 0.049). Zinc oxide resulted in a higher tibia development (i.e. tibia weight and length; p < 0.05) and BWG (p = 0.009) and lower FCR (p < 0.001) compared to ZnSO4. 4. Phytase improved tibia Zn concentration especially in birds given ZnSO4 compared to ZnO (Zn × Phy; p = 0.049). Moderate Ca diets improved tibial characteristics and Zn deposition compared to low Ca diets (p < 0.05). 5. Soluble Zn in the gizzard increased in the presence of phytase (p = 0.011), while higher dietary Ca reduced this in birds receiving ZnO (p = 0.004). In the jejunum, Zn solubility was higher with phytase (p = 0.008). 6. Under the conditions of this study, dietary levels of Ca and microbial phytase affect Zn availability in broilers more than the Zn source.

Effect of Humic acid and levels of Zinc and Boron on Chemical Behavior of Zinc in Calcareous Soil

There are global concerns about the significant increase in the concentrations of heavy elements due to the increase in agricultural, urban and industrial activities, which poses a threat to the natural environment and humans. This study focused on studying the addition of humic acid and different levels of zinc on the presence of zinc in the soil in its different forms and its readiness for the plant to find the best concentration and with the presence or absence of humic acid. This study was carried out on the sunflower crop, as zinc was added at levels of (0, 15 and 30) kg h-1 and humic acid at two concentrations, (0 and 50) kg h-1. Zinc was extracted successively and total and available zinc was measured. The results indicated: Concentration of total and available Zinc associated with carbonate minerals, with oxides, and with organic matter in soil increased with increasing levels of Zinc added to soil, reaching 8.638, 1.049, 1.971, 1.658 and 1.625 mg kg-1 soil, respectively. The effect of added humic acid was significant in reducing the concentrations of total Zinc, Zinc bound to carbonate minerals, bound to oxides and residues. The maximum concentrations in case of not adding acid reached 9.313, 1.8957, 1.424, and 4.300 mg kg-1 soil, respectively, while the effect was positively in increasing available concentration associated with organic matter, as concentration in case of adding humic acid reached 0.851 and 1.4584 mg kg-1 soil, respectively. In the case of adding humic acid, this study is considered good for the results it showed in increasing the available zinc with the presence of humic acid, which is reflected in the plant growth and maintaining this element within the recommended concentrations. We determined Zn speciation in the soil system and evaluated the effects of humic acid application on the basic soil properties and Zn bioavailability.

Assessment of the calcium-silicate Polonite as a sorbent for thin-layer capping of metal contaminated sediment

Sediments contaminated with hazardous metals pose risks to humans and wildlife, yet viable management options are scarce. In a series of laboratory experiments, we characterized Polonite® – an activated calcium-silicate – as a novel sorbent for thin-layer capping of metal-contaminated sediments. We tested a fine-grained by-product from the Polonite production as a cheap and sustainable sorbent. First, Polonite was reacted with solutions of Cu, Pb, and Zn, and the surface chemistry of the Polonite was examined using, e.g., scanning electron microscopy to investigate metal sorption mechanisms. Batch experiments were conducted by adding Polonite to industrially contaminated harbor sediment to determine sorption kinetics and isotherms. Importantly, we measured if the Polonite could reduce metal bioavailability to sediment fauna by performing digestive fluid extraction (DFE). Finally, a cap placement technique was studied by applying a Polonite slurry in sedimentation columns.The results showed rapid metal sorption to Polonite via several mechanisms, including hydroxide and carbonate precipitation, and complexation with metal oxides on the Polonite surface. Isotherm data revealed that the sediment uptake capacity (Kf) for Cu, Pb, and Zn increased by a factor of 25, 21, and 14, respectively, after addition of 5% Polonite. The bioavailability of Cu, Pb, and Zn was reduced by 70%, 65%, and 54%, respectively, after a 25% Polonite addition. In conclusion, we propose that sediment treatment with low doses of the Polonite by-product can be a cheap, sustainable, and effective remediation method compared to other more intrusive methods such as dredging or conventional isolation capping.

Assessment of Heavy Metals (Cr, Cu, Pb, and Zn) Bioaccumulation and Translocation by Erigeron canadensis L. in Polluted Soil

This work aims to assess the bioavailability and bioaccumulation of Cr, Cu, Pb, and Zn in the soil–plant system (Erigeron canadensis L.) in the zone of anthropogenic impact in Dnipro city, a significant industrial and economic centre of Ukraine. Sampling was carried out at three locations at distances of 1.0 km, 5.5 km, and 12.02 km from the main emission sources associated with battery production and processing plants in Dnipro. The concentrations of heavy metals such as Cr, Cu, Pb, and Zn were analysed using atomic emission spectrometry from soil and parts of Erigeron canadensis L. The highest concentrations of elements in the soil, both for the mobile form and the total form, were determined to be 48.96 mg kg−1 and 7830.0 mg kg−1, respectively, for Pb in experimental plot 1. The general ranking of accumulation of elements in all experimental plots, both for the plant as a whole and for its parts, was as follows: Zn &gt; Cu &gt; Cr &gt; Pb. Zn for plants was the most available heavy metal among all studied sites and had the highest metal content in the plant (339.58 mg kg−1), plant uptake index (PUI-506.84), bioabsorption coefficient (BAC-314.9), and bioconcentration coefficient (BCF-191.94). According to the results of the study, it is possible to evaluate Erigeron canadensis L. as a hyperaccumulator of Zn, Cu, and Cr and recommend it for phytoextraction of soils contaminated with Zn, Cu, and Cr and phytostabilization of soils contaminated with Pb.

Prediction of the fluoride contents of different crop species via the random forest algorithm.

Fluoride (F) is a trace element that is essential to the human body and occurs naturally in the environment. However, a deficiency or excess of F in the environment can potentially lead to human health issues. The pseudototal amount of F in soil often does not correlate directly with the F content in plants. Instead, the F content within plants tends to have a greater correlation with the bioavailable F in soils. In large-scale soil surveys, only the pseudototal elemental content of soils is typically measured, which may not be highly reliable for developing agricultural zoning plans. There are significant variations in the ability of different plants to accumulate F from soil. Additionally, due to variations in soil elemental absorption mechanisms among different plant species, when multiple crops are grown in an area, it is typically necessary to study the elemental absorption mechanisms of each crop. To address these issues, in this study, we examined the factors influencing F bioaccumulation coefficients in different crops based on 1:50,000 soil geochemical survey data. Using the random forest algorithm, four indicators-bioavailable P, bioavailable Zn, leachable Pb, and Sr-were selected from among 29 parameters to predict the F content within crops to replace bioavailable F in the soil. Compared with the multivariate linear regression (MLR) model, the random forest (RF) model provided more accurate and reliable predictions of the fluoride content in crops, with the RF model's prediction accuracy improving by approximately 95.23%. Additionally, while the partial least squares regression (PLSR) model also offered improved accuracy over MLR, the RF model still outperformed PLSR in terms of prediction accuracy and robustness. Additionally, it maximized the utilization of existing geochemical survey data, enabling cross-species studies for the first time and avoiding redundant evaluations of different types of agricultural products in the same region. In this investigation, we selected the Xining-Ledu region of Qinghai Province, China, as the study area and employed a random forest model to predict the crop F content in soils, providing a new methodological framework for crop production that effectively enhances agricultural quality and efficiency.

Organic Zn and nano-Zn amino acids chelates modulate quality growth attributes and antioxidants activity for biofortified apple (Malus x domestica Borkh.) production

Zinc biofortification increase nutritional content of crops to combat Zn deficiency in human diets. Foliar Zn bio-organics can significantly improve Zn content of fruit crops. This method is efficient, can be tailored to specific crop needs, and is crucial for enhancing the nutritional quality of food crops, contributing to better human health outcomes. In order to evaluate the efficacy of foliar sprays in promoting plant growth and development, the study evaluated the comparative efficacy of zinc amino acid complexes with zinc sulphate in apple (Malus × domestica Borkh.) cv. Gala Schniga Schnico during the years 2022 and 2023. Different Zn nutrient sources namely, Zn glycinate (Zn-Gly), Zn gluconate (Zn-Glu), Zn amino acid chelate (Zn-AAC), nano Zn amino acid chelate (NZn-AAC) were applied at the rate of 200 and 400 mg/L each and conventional ZnSO4 at 1250 mg/L with three replicates. Foliar application of the Zn nutrient sources was executed at four stages i.e., 15 days before petal fall, petal fall, 15 days after petal fall, and after harvest. The results revealed that NZn-AAC at 400 mg kg-1 registered the maximum increase in vegetative growth and flowering traits. The superior treatment also exhibited highest fruit set (62.90 %) and fruit yield (5.62 kg/tree) in apple. Fruit quality parameters, in terms of TSS, total sugars, ascorbic acid and anthocyanin contents were increased by 22.9, 17.8, 50.2, and 16.6 per cent, respectively through superior treatment. Fruit flesh and peel nutrient content in terms of P, K, Ca, Mg and Zn also showed improvement through NZn-AAC400 compared to control. Maximum decrease in phytic acid (1.09 %) and increase in ursolic acid (273.95 µg/mL) were also reported with NZn-AAC400. The differences between Zn nutrient sources were analysed using PCA, which explained 95.70 per cent (PC1), 97.81 per cent (PC2), 99.11 per cent (PC3), 99.42 per cent (PC4) and 99.63 per cent (PC5) of the cumulative variance based on Eigen value (>1). In accordance with the results, Zn amino acid complexes emerged as beneficial environment-friendly Zn source for improving growth, fruit yield, quality with higher Zn bio-availability compared to ZnSO4.

Spatial patterns and mechanism of the impact of soil salinity on potentially toxic elements in coastal areas

Soil salinization and heavy metal pollution in the Yellow River Delta region have elicited increasing concern. Therefore, revealing the underlying mechanism of the impact of soil salinity on potential toxic elements (PTEs) is crucial for environmental protection and the rational utilization of resources in this area. In this study, we employed CatBoost–SHAP and multiscale geographically weighted regression (MGWR) models to comprehensively investigate the spatial effects of soil electrical conductivity (EC1:5) on PTEs. Additionally, we employed a space–for–time substitution strategy with the aim of investigating how increasing soil salinity, represented by EC1:5, K+, Na+, Ca2+, and Mg2+, affects the bioavailability of PTEs over time. The primary findings are as follows: (1) for most PTEs, the influence of soil EC1:5 on the bioavailable forms of these elements surpassed its impact on their total concentrations. (2) The results of the MGWR model indicated that exchangeable Ca (aCa) in the soils of the eastern coastal areas markedly increased the bioavailable Cd (aCd), bioavailable Cu (aCu), and bioavailable Zn (aZn). (3) When the soil EC1:5 ranges between 2 and 6 dS/m, exchangeable Na (aNa) primarily competed for the adsorption sites of bioavailable Pb (aPb). However, as the soil EC1:5 increases to 6–10 dS/m, exchangeable Mg (aMg) and aCa became the primary competing ions, with aMg playing a more significant role than aCa. These findings provide valuable theoretical insights and practical guidance for saline-alkali soil improvement and PTEs pollution control in the Yellow River Delta region, thereby providing a foundation for sustainable environmental management and resource utilization.

Comparative effects of dietary zinc nanoparticle and conventional zinc supplementation on broiler chickens: A meta-analysis.

Zinc (Zn) is important for various physiological processes in broiler chickens, including protein and carbohydrate metabolism, growth, and reproduction. The gastrointestinal absorption of Zn in broiler chickens was notably low. One approach that has been explored for enhancing the bioavailability of Zn is the development of Zn nanoparticles (NPs). Zn is required for various physiological processes in broiler chickens, including protein and carbohydrate metabolism, growth, and reproduction. Therefore, this study aimed to assess the impact of conventional Zn and Zn NPs on broiler chickens using a meta-analysis methodology. A database was built from published literature to evaluate the effects of the addition of Zn NPs and conventional Zn on broiler chicken responses, including the following parameters: production performance; carcass cuts; visceral organ weight; lymphoid organ weight; nutrient digestibility; intestinal villi; mineral Zn, calcium, and phosphorus concentrations; hematology; blood parameters; immunoglobulin; and intestinal bacterial population. Various scientific platforms, including Scopus, Web of Science, PubMed Central, and Google Scholar, were used to search for peer-reviewed articles. A database was created from 25 studies that met the inclusion criteria. The data were then processed for a meta-analysis using a mixed-model methodology. Different types of Zn (NPs versus conventional) were considered fixed effects, different studies were treated as random effects, and p-values were used as model statistics. Across the parameters observed in this study, the use of Zn NPs was more efficient in Zn utilization than conventional Zn, as evidenced by the average dose of Zn NPs being much lower than that of conventional Zn (79.44 vs. 242.76 mg/kg) yet providing similar (p > 0.05) or even significantly better effects (p < 0.05) compared to conventional Zn usage. This investigation revealed the beneficial influence of Zn NPs in broiler chickens compared to the conventional utilization of Zn through an all-encompassing meta-analysis. Moreover, Zn NPs have proven to be more effective in Zn utilization when juxtaposed with conventional Zn, as demonstrated by the significantly lower quantity of Zn NPs administered compared to conventional Zn, while yielding comparable or even superior outcomes compared to the traditional utilization of Zn. A limitation of this study is that the Zn NPs used were sourced from inorganic Zn NPs. Therefore, future research should focus on evaluating the efficiency of organic Zn NPs in broiler chicken feed.

Synthesis of ZnO nanoparticles from the medicinal plant Salvia fruticosa Mill.: Green approach for potential biomedical application against Zn deficiency in humans

We hypothesized that we could prepare ZnO nanoparticles (ZnO NPs) as a biomedical application treatment of zinc deficiency in human populations. In this study, we report a formulation prepared using a low-cost method for the green synthesis of ZnO NPs by utilizing the medicinal species Salvia fruticosa as natural raw material and Zn(NO3)2∙6H2O as a Zn source. The final product was identified and characterized by elemental analysis using X-ray energy-scattering spectroscopy (EDS), ultraviolet–visible spectroscopy (UV-VIS Spectroscopy), X-ray powder diffraction (XRD), and morphometric analysis using scanning electron microscopy (SEM). Finally, crystallization was studied using transmission electron microscopy (TEM). Afterward, ZnO NPs thus produced were utilized for foliar spraying on S. fruticosa open cultures, and Zn fortification in the foliage. Then, their effects on the biosynthesis of essential oils, and Zn bioavailability to humans were studied through different modes of consumption.ZnO NPs produced using our method were spherical while some were hexagonal, with an average size of approximately 22 nm, based on XRD results. The green synthesis method devised in this study afforded ZnO NPs from Zn(NO3)2∙6H2O with a 95 % yield, and consequently yielded economic benefits with respect to the current market prices. Foliage Zn fortification and the desired features were successfully achieved using ZnO NPs, and the proper mode of consumption of this medicinal plant has been recommended in this study.In conclusion, the methodology described in this study enables eco-friendly green synthesis of ZnO NPs at a low cost using S. fruticosa and puts forward a contemporary and integrated biomedical use of ZnO NPs to treat disorders resulting from or related to Zn deficiency.

Effects of Selenate Application on Growth, Nutrient Bioaccumulation, and Bioactive Compounds in Broccoli (Brassica oleracea var. italica L.)

The biofortification of edible crops with selenium (Se) is a common and effective strategy to address inadequate Se intake, which is suffered by millions of people worldwide. However, there is little information regarding the effects of this practice on crops belonging to the important Brassica family. To evaluate the efficacy of foliar Se application on broccoli, four treatments with varying Se concentrations were tested: 0%, 0.05%, 0.10%, and 0.15% (w/v), applied as sodium selenate during the early flowering stage. Although no overall effects on growth and biomass parameters were observed, the results indicate that the lowest Se dose (0.05-Se) was sufficient to notably increase Se concentration in the florets, even after boiling. Based on the increase to 14.2 mg Se kg−1 of dry matter in this broccoli fraction, it was estimated that consuming a 100-gram portion of boiled florets biofortified with 0.05% Se would provide approximately 140 µg of Se, which could be sufficient to potentially improve human selenium status, as previously documented. Moreover, the results obtained underscore how the application of this small dose was also adequate to reduce phytate concentration in the florets and to increase antioxidant and polyphenol concentrations, thereby improving the concentration and bioavailability of other essential nutrients, including Ca, Mg, Fe, and Zn, along with improving its quality as an antioxidant food.

Zinc isotope fractionation during coprecipitation with amorphous iron (hydr)oxides

Coprecipitation facilitates the incorporation of Zn into the lattice of Fe (hydr)oxide, which is a crucial mechanism causing low Zn bioavailability in widespread Zn-deficient soils. Zn isotopes are a potential indicator of the coprecipitation of Zn and Fe (hydr)oxides in soils. However, the Zn isotope fractionation caused by coprecipitation with amorphous Fe (hydr)oxides (e.g., ferrihydrite) and the impact of environmentally relevant conditions remain unknown. Here, the molecular mechanism and impact factor of Zn isotope fractionation during Zn2+-Fe3+ coprecipitation under natural soil conditions (including different pH values and initial Zn/Fe ratios) were investigated by combining isotope ratio measurements, extended X-ray absorption fine structure (EXAFS) analyses, and density functional theory (DFT) geometry optimization. The results show that aqueous Zn (Znaq) can be complexed on the ferrihydrite surface (Znads) with positive isotope fractionation (Δ66Znads–aq = 0.42 ± 0.09 ‰) or directly incorporated into the ferrihydrite lattice with slightly negative isotope fractionation (Δ66Znstru-aq = −0.08 ± 0.03 ‰). In addition, over time, the surface-complexed Zn can further transform to a layered structure on the surface but exhibits limited Zn isotope fractionation. According to Zn K-edge EXAFS, the Zn isotope fractionation of surface complexation and incorporation of Znaq are related to the decrease in the Zn–O bond strength in the order surface complexed Zn (RZn–O = 2.00 Å) > aqueous Zn (RZn–O = 2.08 Å) > directly incorporated Zn (RZn–O = 2.06–2.07 Å with slight distortion). The limited Zn isotope fractionation associated with the transformation of Znads is related to the reconfiguration of Znads during the nucleation of octahedral Zn layer structures. Furthermore, the primary process controlling Zn isotope fractionation is different under varying experimental conditions, leading to distinct Zn isotope fractionation between the bulk solid and solution during Zn–Fe coprecipitation. Low pH values (5.0–6.0) and initial Zn/Fe ratios (0.01–0.02) favor the direct precipitation of Znaq, resulting in slightly negative Zn isotope fractionation between the bulk solid and solution. In contrast, high pH values (7.0–7.5) and initial Zn/Fe ratios (0.1–0.2) favor surface complexation and the transformation of Znads, leading to heavy Zn isotope enrichment in the bulk solid. These findings offer novel insights into the primary mechanism through which Fe (hydr)oxides regulate Zn bioavailability in Zn-deficient soils and provide experimental evidence supporting the potential application of Zn isotopes as an indicator for comprehending the fate of Zn controlled by Fe (hydr)oxides in soils.

Application of zinc modified biochars to enhance zinc availability, speciation and bajra growth in Zn-deficient soil

Zinc deficiency poses a serious threat to numerous crops and global human populations. Recently, soil biochar amendment has being promoted as a sustainable farming method. However, its consequence on the bioavailability of Zn in cereal crop has not been fully addressed. In the present study, 0.01% Zn-SO4 (w/w) was loaded in fruit waste, farmyard manure and coconut shell pyrolysis at 400 ℃, for 2 h to make fruit waste Zn-modified biochar (FWZn-MBC), farmyard manure Zn-modified biochar (FYZn-MBC) and coconut shell Zn-modified biochar (CSZn-MBC). Except control treatment, all the modified biochars were applied at 1, 2 and 4% doses on zinc availability, speciation, bajra growth and chemical properties in Zn-deficient soil. The obtained results showed that Zn mobility in soil was 70.04% with application of FYZn-MBC 4% as compared with other treatments. The maximum uptake of Zn in shoot and root by bajra plant was observed by 74.02% and 53% with addition of FYZn-MBC 4% as compared with control soil, due to an increase of soil organic matter. The chlorophyll SPAD values in the bajra aerial surface was increased from 30.23 to 39.24 with application FYZn-MBC 4% than control. The exchangeable fraction of Zn was increased from 7.34 to 14.71% with application of FYZn-MBC 4%. The correlation matrix results indicated that CaCO3 was positively correlated with soil pH. Soil organic matter was highly significant correlated with chlorophyll. Overall, future studies must be carried out to examine the long-term impact of FYZn-MBC 4% on Zn phytoavailbility in Zn-deficient soil.

Biochar derived from animal and plant facilitates synergistic transformation of heavy metals and phosphorus in sewage sludge composting

This study investigated the influence of plant-derived biochar (PB) and animal-derived biochar (AB) on behavior of heavy metals and phosphorus fractions during sewage sludge composting. PB was highly effective in reducing the bioavailability of Zn and Cu by 39% and 50%, respectively, while AB decreased the bioavailability of Pb (30%) and Cd (12%). Both biochar increased available phosphorus by over 38%. Acid extractable and bioavailable Pb in AB, and water-soluble, oxidizable and total Zn, acid extractable and oxidizable Cu in PB were positively correlated with moderately resistant organic phosphorus (MROP). Besides, in AB, Cd had strong and positive correlation with highly resistant organic phosphorus (HROP). This suggested biochar facilitated the formation of stable organometallic complexes through binding metal ions to phosphorus fractions, with notable differences based on biochar source. FT-IR showed biochar promoted humification, with PB enhancing carboxyl and polysaccharide formation, while AB encouraged quinone and aryl ether structures. These surface functional groups on the biochar likely contributed to heavy metals and phosphorus binding through chelation, adsorption, and electron shuttling.

Biogenic-to-lithogenic handoff of particulate Zn affects the Zn cycle in the Southern Ocean.

Zinc (Zn) is vital to marine organisms. Its active uptake by phytoplankton results in a substantial depletion of dissolved Zn, and Zn bound to particulate organic matter replenishes dissolved Zn in the ocean through remineralization. However, we found that particulate Zn changes from Zn bound to phosphoryls in cells to recalcitrant inorganic pools that include biogenic silica, clays, and iron, manganese, and aluminum oxides in the Southern Ocean water column. The abundances of inorganic pools increase with depth and are the only phases preserved in sediments. Changes in the particulate-Zn speciation influence Zn bioavailability and explain the decoupling of Zn and phosphorus and the correlation of Zn and silicon in the water column. These findings reveal a new dimension to the ocean Zn cycle, implicating an underappreciated role of inorganic Zn particles and their impact on biological productivity.

Mikania micrantha Kunth and its derived biochar impacts on heavy metal bioavailability and siderophore-related genes during chicken manure composting

Biochar can potentially reduce heavy metals (HMs) mobility and bioavailability during composting. However, siderophores secreted by functional microbes might lead to the re-mobilization of metals like Cu and Zn. Therefore, this study intended to explore the impacts of Mikania micrantha Kunth (MM) and MM-derived biochar (MMB) in the reduction of Cu and Zn bioavailability, and siderophore-related gene abundances during composting. Compared with MM and corn straw (CS) composts, a significant decline was noticed in the extractable and reducible Cu [(2.3 mg kg−1 + 12.1 mg kg−1), and (3.3 mg kg−1 + 14.6 mg kg−1)], and Zn [(103.1 mg kg−1 + 110.1 mg kg−1), and (109.6 mg kg−1 + 117.2 mg kg−1)] in MMB and corn straw biochar (CSB) composts, respectively. Besides, the lowest relative abundance of HMs-resistant bacteria particularly Corynebacterium (0.40%), Pseudomonas (0.46%), and Enterobacter (0.47%), was noted in MMB compost. Also, a significant increase in sesquiterpenoid and triterpenoid biosynthesis abundance (5.77%) accompanied by a reduction in the abundance of clusters related to siderophore transport, and siderophore transmembrane transporter activity was detected in MMB compost. Multivariate analysis labeled temperature, moisture content, total organic carbon, Corynebacterium, and Bacillus as the primary factors significantly correlated with the Cu and Zn bioavailability (− 0.90 ≤ r ≤ 0.90, P < 0.05). The structural equation model revealed that physicochemical parameters, microbial abundance, and siderophores exert a substantial influence on Cu and Zn bioavailability. Accordingly, MM and its derived biochar are recommended as an effective approach for accelerating Cu and Zn bioavailability reduction and managing the growth and distribution of invasive plants.Graphical

Modulation of Adverse Health Effects of Environmental Cadmium Exposure by Zinc and Its Transporters.

Zinc (Zn) is the second most abundant metal in the human body and is essential for the function of 10% of all proteins. As metals cannot be synthesized or degraded, they must be assimilated from the diet by specialized transport proteins, which unfortunately also provide an entry route for the toxic metal pollutant cadmium (Cd). The intestinal absorption of Zn depends on the composition of food that is consumed, firstly the amount of Zn itself and then the quantity of other food constituents such as phytate, protein, and calcium (Ca). In cells, Zn is involved in the regulation of intermediary metabolism, gene expression, cell growth, differentiation, apoptosis, and antioxidant defense mechanisms. The cellular influx, efflux, subcellular compartmentalization, and trafficking of Zn are coordinated by transporter proteins, solute-linked carriers 30A and 39A (SLC30A and SLC39A), known as the ZnT and Zrt/Irt-like protein (ZIP). Because of its chemical similarity with Zn and Ca, Cd disrupts the physiological functions of both. The concurrent induction of a Zn efflux transporter ZnT1 (SLC30A1) and metallothionein by Cd disrupts the homeostasis and reduces the bioavailability of Zn. The present review highlights the increased mortality and the severity of various diseases among Cd-exposed persons and the roles of Zn and other transport proteins in the manifestation of Cd cytotoxicity. Special emphasis is given to Zn intake levels that may lower the risk of vision loss and bone fracture associated with Cd exposure. The difficult challenge of determining a permissible intake level of Cd is discussed in relation to the recommended dietary Zn intake levels.