The purpose of the study was to understand the mechanisms of biochar-induced changes in the available content of aluminum (Al), cadmium (Cd), zinc (Zn), copper (Cu), and manganese (Mn) in a wide range of soils. Five soils from different regions of the Czech Republic were incubated for 12 weeks with four rates of biochar (0.5%, 2%, 4%, and 8% w/w). The available concentrations of Al, Cd, Zn, Cu, and Mn were determined on the 7th and 84th day of incubation. There was a significant decline in the available content of Al, Zn, Cu, Mn, and Cd except in the available content of Al in one soil, which is characterized by very low Al content, higher cation exchange capacity (CEC), and neutral pH = 7.0. The decline in the mobile contents of Al, Zn, Cu, Mn, and Cd was significant in all cases of 8% biochar rate. The decline in the content of Al, Zn, Cu, Mn, and Cd was mainly due to the increment in soil pH and increment in CEC, decline in dissolved organic carbon (DOC), and the release of exchangeable Ca²⁺ and K⁺ from biochar. The application of high amounts of biochar to soil could increase the available content of some metals like Al. On the other hand, biochar could efficiently reduce the mobility of Al, Zn, Cu, Mn, and Cd in soil, while the decline is mainly caused by biochar-induced changes in soil pH, CEC, DOC, and exchangeable Ca²⁺ and K⁺ content of treated soils.

The connection between sulphur (S) and selenium (Se) metabolism makes rapeseed (Brassica napus) an attractive candidate for Se fortification. Unfortunately, fertilizers may interfere with the availability of selenate (SeO₄^2-) in numerous ways, including both soil and physiological processes. Experiments on two agricultural soils amended with SeO₄^2- (32 μg Se kg⁻¹ soil), sulphate and phosphate (each at three levels of supply) were established to elucidate the effect of these anions on the selenization efficiency. Maximal efficiency in Chernozem soil was roughly two-fold higher (455 μg Se kg⁻¹ seed) than in Cambisol. Sulphate significantly decreased (up to 28%) the seed Se contents in Cambisol, while an enhancement (up to 33%) was found in Chernozem. In the Chernozem, the induction of collective S and Se translocation toward the seed more than compensated for any competition effects due to the highest sulphate supply. In Cambisol, plant Se distribution did not follow that of S as closely as in Chernozem. Phosphate did not significantly alter the fortification efficiency. Resistance of rapeseed proteins to protease hampered a quantitative investigation of changes in Se speciation under different S supplies. Nevertheless, protein-bound selenomethionine was the predominant Se storage form and traces of other Se species were also identified.

This study investigates selenium (Se) biofortification in four strains of the medicinal mushroom Hericium erinaceus using Se-enriched substrates to assess Se uptake, distribution, and its impact on yield. Experimental substrates included lignocellulosic materials fortified with Se (0, 2, 6, and 18 µg/g) in the form of sodium selenite. Se accumulation varied by strain, with M9521 showing the highest bioaccumulation efficiency, particularly for an unknown Se compound, suggesting unique metabolic pathways. Other strains predominantly accumulated selenomethionine. The bioconcentration factor was highest at 6 µg/g Se, indicating optimal efficiency at this level. Moderate Se supplementation (2–6 µg/g) improved yield, though time to harvest was affected by Se levels in some strains. Substrate composition influenced Se uptake, with wheat bran yielding the highest Se content and soybean hulls maximizing biological efficiency. A strong correlation between C/N and Se content was observed. Se distribution was higher in outer basidiocarp layers, and light intensity during cultivation enhanced Se accumulation. Se uptake decreased with subsequent flushes at medium and high supplementation levels, while substrates maintained the same bioavailable Se. The results highlight the potential of Se-enriched Hericium erinaceus as a functional food source and the role of substrate and cultivation conditions in optimizing Se content.

Nowadays, attention is focused on the lack of selenium in the average diet, which is a highly valued element in the body’s antioxidant system. The major metabolites of selenium are selenoproteins, which have an irreplaceable function in the body. This study focused on optimizing conditions for the biofortification of maize (Zea mays L.) with selenium (Se). Three separate pot experiments were conducted to identify the key factors influencing the efficacy of foliar selenium application. The experiments were designed to investigate the effects of different forms of selenium (selenite, selenate, and selenium nanoparticles) on maize development, the influence of the phenological stage of maize at the time of foliar Se application, and the optimal application rate of Se (100, 150, 200, or 250 µg). The results indicated that sodium selenate without a wetting agent was the most effective form for enhancing total Se content in maize, with the greatest accumulation being in leaves (3.01 mg/kg dry matter). Phenological stages (BBCH) 51 and 60 were identified as the most suitable phenological stages for Se application in terms of total Se content about 1 mg/kg in leaves and about 0.4 mg/kg in grain and the presence of organic Se compounds (mostly selenate ion and selenomethionine). We concluded from the study that a foliar application of 200 µg of sodium selenate per pot during these stages resulted in maximum Se uptake without adversely affecting plant yield. Further research is recommended to validate these findings under field conditions, paving the way for improved agricultural practices in selenium biofortification.

Experimental spinach plants grown in soil with (5, 10 and 20 ppm) arsenic (As) contamination were sampled in 21 days after As(V) contamination. Levels of As in spinach samples (from 0.31 ± 0.06 µg g⁻¹ to 302.69 ± 11.83 µg g⁻¹) were higher in roots and lower in leaves, which indicates a low ability of spinach to translocate As into leaves. Species of arsenic, As(III) and As(V), were represented in favor of the As (III) specie in contaminated variants, suggesting enzymatic arsenate reduction. In relation to predominant As accumulation in roots, changes in malondialdehyde levels were observed mainly in roots, where they decreased significantly with growing As contamination (from 11.97 ± 0.54 µg g⁻¹ in control to 2.35 ± 0.43 µg g⁻¹ in 20 ppm As). Higher values in roots than in leaves were observed in the case of 5-methylcytosine (5-mC). Despite that, a change in 5-mC by As contamination was further deepened in leaves (from 0.20 to 14.10%). In roots of spinach, expression of the CDC25 gene increased by the highest As contamination compared to the control. In the case of total phenolic content, total flavonoid content, total phenolic acids content and total antioxidant capacity were higher levels in leaves in all values, unlike the roots.

Honey bees (Apis mellifera L.) represent a random biosampler integrating pollutants over space and time. An effective biomonitor for trace element (TE) pollution should provide a linear response to TE levels in the environment. However, uncertainties in detecting TEs originating in soil limit their use. To address this, nine experimental sites with multiple apiaries were established in the Upper Palatine Forest, Czech Republic. The soils surrounding the hives were characterized by estimations of the pseudototal and (bio)available pools of TEs. Our study aimed to (1) quantify the linear relationships between soil TE indices and TE contents in bees, bee bread, honey, and wax, and (2) verify the biobarrier function protecting honey from TE contamination. Lead (0.046–0.140 µg g−1) and nickel (0.12–4.30 µg g−1) contents in bees showed strong linear correlations with (bio)available Pb (0.012–0.254 µg g−1) and pseudototal Ni (17.1–36.4 µg g−1) in soil (Pearson's r = 0.95 and 0.88, p < 0.005), providing high spatial resolution. A weaker, insignificant correlation was observed for chromium (Cr; r = 0.65) and vanadium (V; 0.44), while no correlation was found for cadmium (Cd). However, the lack of associations for Cr, V, and Cd may result from the low soil TE levels in the region, negligible differences among the majority of sites, and temporal concerns related to different time scales of the biomonitors, impacting the linear model's sensitivity. Biochemical traits in bees, such as the biobarrier function, and different bioavailability of TEs from ingested matter may affect the matrix-to-matrix transfer of TEs in an element-dependent manner. Consequently, the linear response of bee-related biomonitors to TE levels in the environment may significantly deteriorate. Environ Toxicol Chem 2024;43:288–298. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.