Search Results (155)

Heavy metal contamination in paddy fields poses serious risks to food safety and crop productivity. This study evaluated the potential of native soil fungi as bioinoculants to reduce metal uptake in rice cultivated under contaminated conditions. Eight fungal strains—four indigenous and four allochthonous—were selected based on their plant growth-promoting traits, including siderophore production and phosphate solubilization. Additional metabolic analysis confirmed the production of bioactive secondary metabolites. In a greenhouse experiment, three rice cultivars were grown under permanent flooding (PF) and alternate wetting and drying (AWD) in soil enriched with arsenic, cadmium, chromium, and copper. Inoculation with indigenous fungi under AWD significantly reduced the arsenic accumulation in rice shoots by up to 75%. While AWD increased cadmium uptake across all cultivars, fungal inoculation led to a moderate reduction in cadmium accumulation—ranging from 15% to 25%—in some varieties. These effects were not observed under PF conditions. The results demonstrate the potential of native fungi as a nature-based solution to mitigate heavy metal stress in rice cultivation, supporting both environmental remediation and sustainable agriculture. Full article

The co-contamination of arsenic (As) and cadmium (Cd) in paddy soils threatens rice safety, yet synergistic mitigation strategies using silicon (Si) and ferrous sulfate (FeSO₄) remain underexplored. This study integrated hydroponic and soil pot experiments to evaluate Si-FeSO₄ interactions on As/Cd accumulation and rice growth. Hydroponic trials employed 21-day-old rice seedlings exposed to 0.5 mg As(III)/Cd(II) L⁻¹ with/without 70 mg Si L⁻¹ and 30–70 mg Fe L⁻¹, followed by sequential harvesting at 14 and 21 days. Soil experiments utilized co-contaminated paddy soil (50 mg As kg⁻¹ and 1.2 mg Cd kg⁻¹) amended with Si (80 or 400 mg kg⁻¹) and Fe (100 or 1000 mg kg⁻¹), with pore water dynamics monitored over 120 days. Hydroponic results demonstrated that 70 mg Si L⁻¹ combined with 30 or 70 mg Fe L⁻¹ enhanced shoot biomass by 12–79% under As stress, while simultaneously reducing shoot As concentrations by 76–87% and Cd concentrations by 14–33%. Iron plaque induced by FeSO₄ exhibited contrasting adsorption behaviors: hydroponic roots immobilized both As and Cd (p < 0.01), whereas roots in soil primarily retained Cd (p < 0.05). In soil experiments, the optimal treatment of 100 mg Fe kg⁻¹ and 400 mg Si kg⁻¹ (Fe₁ + Si₂) increased grain biomass by 54%, while reducing As and Cd concentrations by 37% and 42%, respectively. However, a higher Fe dosage (Fe₂: 1000 mg kg⁻¹ Fe) paradoxically increased grain Cd concentrations. Mechanistically, Si amendment elevated soil pH (Δ + 0.72), facilitating Cd immobilization, while FeSO₄ lowered pH (Δ−0.07–0.53), increasing Cd mobility. A strong correlation between soluble Cd and plant uptake was observed (p < 0.01), while changes in As accumulation were unrelated to aqueous behavior. The optimized Si/Fe molar ratio of 7.95:1 effectively mitigated As and Cd co-accumulation, offering a dual-functional strategy for safe rice cultivation in contaminated soils. Full article

Arsenic, a potent metalloid contaminant of drinking water, is known for its ability to act as an initiator and modulator of disease in a variety of human tissues. Upon ingestion, arsenic is bio-transformed in the liver into a variety of metabolites, including arsenite. Arsenite permeates the blood–brain barrier (BBB), inducing oxidative stress that can be detrimental to brain neurons. As the primary glial cell at the BBB interface, astrocytes play a pivotal role in detoxifying xenobiotics such as arsenite via the production of the tripeptide antioxidant γ-glutamylcysteine, or glutathione (GSH). In this study, we assessed the mRNA levels of key components of the GSH synthetic pathway in astrocytes exposed to arsenite compared to vehicle controls. These components included xCT [substrate-specific light chain of the substrate importing transporter, system x_c⁻ (Sx_c⁻)], glutamate-cysteine ligase [both catalytic (GCL_C) and modifying (GCL_M) subunits], and glutathione synthetase (GS). Additionally, we analyzed protein levels of some components by Western blotting and evaluated functional activity of Sx_c⁻ using a fluorescence-based cystine uptake assay. Finally, we utilized a luminescence-based glutathione assay to determine the intracellular and extracellular GSH content in arsenite-treated cells. Arsenite significantly increased xCT, GCL_C, GCL_M, and GS mRNA levels, an effect blocked by the transcriptional inhibitor actinomycin D (ActD). A corresponding increase in Sx_c⁻ activity was also observed in the arsenite treatment groups, along with significant increases in GCL_C and GCL_M protein expression. However, no increase in GS protein expression was detected. Finally, arsenite treatment significantly increased extracellular GSH levels, an effect which was also prevented by the inclusion of ActD. Overall, our study provides evidence that arsenite transcriptionally regulates several cellular processes necessary for GSH synthesis in primary cortical astrocyte cultures, thereby contributing to a better understanding of how this environmental toxicant influences antioxidant defenses in the brain. However, these results should be interpreted with caution regarding their applicability to vivo systems. Full article

Soil contamination with arsenic (As) is becoming a serious concern for living organisms. Arsenic is a nonessential metalloid for plants, humans, and other living organisms. Biochar (BC) is a very effective amendment to remediate polluted soils and it received great attention owing to its appreciable results. Arsenic toxicity negatively affects plant morph-physiological and biochemical functioning and upsurges the generation of reactive oxygen species (ROS), which negatively affect cellular structures. Arsenic toxicity also reduces seed germination and impedes plant growth by decreasing nutrient uptake, causing oxidative damage and disrupting the photosynthetic efficiency. Plants use different strategies like antioxidant defense and increased osmolyte synthesis to counteract As toxicity; nevertheless, this is not enough to counter the toxic impacts of As. Thus, applying BC has shown tremendous potential to counteract the As toxicity. Biochar application to As-polluted soils improves water uptake, maintains membrane stability and nutrient homeostasis, and increases osmolyte synthesis, gene expression, and antioxidant activities, leading to better plant performance. Additionally, BC modulates soil pH, increases nutrient availability, causes As immobilization, decreases its uptake and accumulation in plant tissues, and ensures safer production. The present review describes the sources, toxic impacts of As, and ways to lower As in the environment to decrease its toxic impacts on humans, the ecosystem, and the food chain. It concentrates on different mechanisms mediated by BC to alleviate As toxicity and remediate As-polluted soils and different research gaps that must be fulfilled in the future. Therefore, the current review will help to develop innovative strategies to minimize As uptake and accumulation and remediate As-polluted soils to reduce their impacts on humans and the environment. Full article

Potentially toxic elements (PTE), such as cadmium (Cd), lead (Pb), and arsenic (As), threaten rice (Oryza sativa L.) crop productivity and pose significant risks to human health when they are present in soil. This review summarizes the current understanding of soil and rice contamination with As, Cd, and Pb to provide an in-depth understanding of the dynamics of these contaminants and the mechanisms regulating their flow from soil to plants. It focuses on the following aspects: (1) these metals’ geochemical distribution and speciation in soil–rice systems; (2) factors influencing the transformation, bioavailability, and uptake of these metals in paddy soils; (3) metal uptake, transport, translocation, and accumulation mechanisms in rice grains; and (4) the roles of transporters involved in metal uptake, transport, and accumulation in rice plants. Moreover, this review contributes to a clearer understanding of the environmental risks associated with these toxic metals in soil–rice ecosystems. Furthermore, it highlights the challenges in simultaneously managing the risks of As, Cd, and Pb contamination in rice. The study findings may help inspire innovative methods, biotechnological applications, and sustainable management strategies to mitigate the accumulation of As, Cd, and Pb in rice grains while effectively addressing multi-metal contamination in paddy soils. Full article

Arsenic (As), a toxic element, is widely distributed in soil and irrigation water. Rice (Oryza sativa L.), the staple food in Southern China, exhibits a greater propensity for As uptake compared to other crops. Arsenic pollution in paddy fields not only impairs rice growth but also poses a serious threat to food security and human health. Nevertheless, the molecular mechanism underlying the response to As toxicity has not been completely revealed until now. Transcriptome analysis represents a powerful tool for revealing the mechanisms conferring phenotype formation and is widely employed in crop breeding. Consequently, this review focuses on the recent advances in transcriptome analysis within the realm of low As breeding in rice. It particularly highlights the applications of transcriptome analysis in identifying genes responsive to As toxicity, revealing gene interaction regulatory modules and analyzing secondary metabolite biosynthesis pathways. Furthermore, the molecular mechanisms underlying rice As tolerance are updated, and the recent outcomes in low As breeding are summarized. Finally, the challenges associated with applying transcriptome analysis to low-As breeding are deliberated upon, and future research directions are envisioned, with the aim of providing references to expedite high-yield and low-arsenic breeding in rice. Full article

Phytoremediation represents a potentially effective and environmentally friendly technology to remediate arsenic (As) in mine waste soils. However, soil amendments are often required to improve phytoremediation due to depleted nutrients in mine waste. This study aims to assess the effect of biosolids biochar, applied at different rates (0%, 5%, and 10%) on As phytoremediation using three plant species: Poa labillardieri, Rytidosperma caespitosum, and Juncus pauciflorus. This study was conducted in a replicated greenhouse pot study using soil from an abandoned mine site. Dry plant biomass, As concentration in plants and soil, and soil microbial abundance were investigated. Juncus pauciflorus produced eight times more root and shoot biomass than R. caespitosum in soils amended with 10% biochar. The highest As uptake was also observed in J. pauciflorus grown in soils amended with 10% biochar (7.10 mg/plant), while R. caespitosum had the lowest As uptake in soils without biochar (0.16 mg/plant). In soils amended with 10% biochar, the total bacterial community decreased to approximately 8.50 log₁₀ copies/g, compared to the initial soil (9.05 log₁₀ copies/g), while the number of gene copies of the nifH gene increased, suggesting the importance of nitrogen-fixing bacteria to promote plant growth. Taguchi analysis confirmed that plant species was the key factor for As phytoremediation, followed by biochar application dose. This study showed that J. pauciflorus and the addition of 10% biochar was the best treatment for remediating As-contaminated mine waste, offering the potential for use commercially. Moreover, the utilisation of biochar derived from biosolids as a soil amendment for enhancing phytoremediation represents good circular economy practice to manage excessive biosolids production. Full article

The contamination of soil with arsenic (As) and heavy metal is an increasing global environmental concern. The objective of this study was to rehabilitate soil contaminated with As, Pb, and Zn using fishery by-products as stabilizers to achieve both soil restoration and waste resource recycling. Cockle shells (CS) and manila clam shells (MC), selected as fishery by-product stabilizers, were processed into −#10-mesh and −#20-mesh materials. Additionally, a −#10-mesh material was calcined at a high temperature to produce calcined cockle shells (CCS) and calcined manila clam shells (CMC). Contaminated soil was treated with 2–10 wt% of these stabilizers and subjected to wet incubation for 1–4 weeks. Subsequently, the concentrations of As, Pb, and Zn eluted by 0.1 M HCl were evaluated. Additionally, lettuce was grown in stabilized soil to evaluate the reduction in contaminant mobility. The stabilization treatment results indicated that the concentrations of eluted As, Pb, and Zn were significantly reduced when treated with the −#10-mesh and −#20-mesh CS and MC, and they were rarely detected when treated with the calcined materials (CCS and CMC). The Pb concentration in lettuce grown in the contaminated soil pot exceeded the criterion for leafy vegetables (0.3 mg/kg); however, Pb was not detected in lettuce from the stabilized soil pot. An X-ray diffraction (XRD) analysis revealed that CaCO₃, the main component of CS and MC, was converted to CaO after calcination. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and SEM elemental dot map analyses revealed that the immobilization of As was related to Ca–As precipitation and the immobilization of Pb and Zn to the pozzolanic reaction. Thus, recycling and processing CS and MC as stabilizers for contaminated soil can restore the agricultural value of the soil by immobilizing As, Pb, and Zn into safe forms, thus effectively preventing their uptake by crops. Full article

Arsenic (As), a well-known ‘traditional’ environmental contaminant, and carbamazepine (CBZ), an emerging contaminant of a pharmaceutical category, are both frequently detected in the environment and have been shown to exhibit toxicity at exposure concentrations present in the environment. This study aimed to assess the single and combined exposure effects of these pollutants on the adult common vole (Microtus arvalis L.), a model mammalian organism. This study assessed As and CBZ accumulation, their biotransformation processes, and antioxidant enzyme defence responses after sole and combined exposure. The animals were fed a diet containing either a low (1.25 mg/kg) or high level (166 mg/kg) of As. Moreover, half of the animals were exposed to CBZ via drinking water infused with 10 ng/L of CBZ, and the second half had the use of drinking water devoid of CBZ. The results showed enhanced total As and As species contents in the organs of the As + CBZ exposure group compared to the As exposure group. High As exposure in the As + CBZ group did not cause an enhanced uptake of CBZ in the liver compared to the CBZ exposure group. There was a potential accumulation of CBZ in the liver of the CBZ exposed groups (CBZ and As + CBZ), raising concerns about potential toxic effects in mammals from long-term exposure. Glutathione peroxidase (GPx) activity, reflecting the antioxidant enzyme defence responses against single and co-exposure of the two pollutants, showed that the CBZ group exhibited comparable activity to the control group, while the As group had down-regulation and the As + CBZ group had up-regulation. These findings suggest that the CBZ group experienced minimal oxidative stress conditions, similar to the control group. The As group showed a rapid adaptation response to curtail or offset potential oxidative stress tissue damage conditions, compared to the slow adaptation/response in the As + CBZ group. The findings of this experiment indicate that the possible interactions of various environmental pollutants could alter the potential effects of the individual pollutants after a sole exposure. These findings indicate the necessity of investigating these interactions for better understanding of the potential risk of these pollutants in real environmental conditions. Full article

Phytoremediation is an economically viable and environmentally friendly technique among various arsenic-contaminated soil remediation technologies. Field plot experiments were conducted to investigate the effects of peanut intercropping with sunflower, lucerne, and jute on the growth and development of intercropped crops and the efficiency of arsenic (As) remediation in polluted soil within the intercropping system. The results indicate that intercropping peanuts with other crops can enhance the biomass and yield of the crops. The land equivalent ratios (LER) of the three intercropping patterns were 1.03, 1.70, and 1.17, respectively. The intercropping pattern also influences the absorption and accumulation of As in crops. Total arsenic accumulation in peanuts intercropped with jute reached 493 μg·plant⁻¹, which was significantly higher by 29.5% compared to peanut monoculture. Additionally, the translocation factor (TF) and bioaccumulation factor (BCF) of peanut seeds were significantly higher in peanut-jute intercropping compared to other treatments, but the As content of peanut seeds in all treatments complied with national food safety standards (GB2762-2022, 0.5 mg·kg⁻¹). Intercropping of peanuts altered the pH and Eh values of rhizosphere soil, further influencing the percentage content of various forms of As in the soil, and reducing the mobility and effectiveness of As. The metal removal equivalent ratios (MRER) for the three intercropping patterns were 1.30, 2.11, and 1.26, respectively. The intercropping of peanuts and lucerne resulted in an MRER of 2.11. It indicates that peanut intercropping has a significant promotion and high restoration efficiency on the growth and development of lucerne. Therefore, among the three patterns, the peanut intercropping lucerne pattern has the best effect in applying to contaminated soil, and can better realize the integration of economic and ecological benefits. Full article

Nowadays, arsenic (As) accumulation in agricultural soils and its transfer in crop yields is representing a growing concern that threatens food safety and security in the Mediterranean environment. Soil tillage and fertilization may increase the accumulation of As in plant tissues; therefore, there is a need to develop sustainable agronomical practices capable of supporting crop yield while mitigating As accumulation. The current study was carried out through a 7-year experiment with the aim of evaluating the As uptake by different parts of the durum wheat plant. The experimental treatments include the following: (i) three soil tillage practices (plowing, subsoiling, and spading) and (ii) two fertilization methods (mineral and organic). A factorial randomized complete block design with three replications was adopted. The experimental period refers to the 2018/2019, 2019/2020, and 2020/2021 growing seasons. The results suggest that the maximum level of As was found in plant roots and the minimum in wheat kernels. The chemical fertilization as 2020 × Mineral (1.522 mg As kg⁻¹ d.m.) and 2020 × Plowing (1.855 mg As kg⁻¹ d.m.) had the maximum As content in the roots. Conversely, the content of As was at a minimum in the wheat kernels for organic fertilization as 2021 × Organic (0.012 mg As kg⁻¹ d.m.) and subsoiling tillage as 2021 × Subsoiling (0.008 mg As kg⁻¹ d.m.). Moreover, the application of an organic fertilization source as a tool for enhancing the soil organic matter content also significantly decreased the As content. The results suggest that reduced tillage practices and the adoption of organic amendment could be classified as sustainable agronomic practices in agri-food systems, which are able to improve plant quality and assure a safe consumption of wheat kernels. Full article

Micro-nano plastics (MNPs) are emerging environmental and food contaminants that are raising serious health concerns. Due to the polycontamination of the food web with environmental pollutants (EPs), and now MNPs, the co-ingestion of EPs and MNPs is likely to occur, and the potential synergistic effects of such co-ingestions are completely unstudied. In this study, we therefore sought to determine the effects of the two model EPs, arsenic and boscalid, on the uptake and toxicity of two model MNPs, 25 and 1000 nm polystyrene (PS-25 and PS-1000), and vice versa, employing a triculture small intestinal epithelium model combined with simulated digestion. In 24 h triculture exposures, neither MNPs, EPs, nor MNPs + EPs caused significant toxicity. The presence of PS-25 significantly increased arsenic uptake (from 0.0 to 5.8%, p < 0.001) and translocation (from 5.2 to 9.8%, p < 0.05) but had no effect on boscalid uptake or translocation, whereas PS-1000 had no effect on the uptake or translocation of either EP. The uptake of both PS MNPs was also increased by EPs, rising from 10.6 to 19.5% (p < 0.01) for PS-25 and from 4.8 to 8.5% (p < 0.01) for PS-1000. These findings highlight the need for further studies to assess MNP-EP interactions and possible synergistic adverse health impacts. Full article

Microbes have been shown to adapt to stressful or even lethal conditions through displaying genome plasticity. However, how bacteria utilize the ability of genomic plasticity to deal with high antimony (Sb) stress has remained unclear. In this study, the spontaneous mutant strain SMAs-55 of Achromobacter sp. As-55 was obtained under antimonite (Sb(III)) stress. SMAs-55 displayed significantly increased Sb(III) resistance, but it lost the ability to oxidize arsenite (As(III)) by deleting an entire gene island containing genes encoding functions involved in As(III) oxidation, arsenic (As)/Sb resistance and phosphate transport. This study suggests that genetic plasticity has played an important role in As-55 adaption to Sb(III) stress. Transcriptomic analysis found that genes encoding functions involved in capsule polysaccharide synthesis, as well as functions correlated to stress adaptation, ATP production, and metabolism were more strongly expressed in SMAs-55. In addition, a lower intracellular Sb(III) accumulation in SMAs-55 was observed. These findings indicate that reduced uptake through increased capsule biosynthesis was an effective way for SMAs-55 to adapt to an environment displaying high levels of Sb. This study helps us to better understand the evolutionary processes enabling survival of microbes and microbial community in contaminated environments. Full article

Heavy metal pollution has become increasingly severe, with distinctive physiological characteristics of rice leading to significant accumulation of arsenic (As) and cadmium (Cd) in grains, posing serious health risks. Biological soil crusts (BSC) are common in paddy soils and exhibit a strong capacity to bind trace heavy metals. This study investigated the effects of exogenous iron (Fe)/manganese (Mn) and urea on the effectiveness of BSC (20 mg L⁻¹) in removing As (2 mg L⁻¹) and Cd (100 μg L⁻¹) and analyzed the heavy metal distribution. Fe/Mn addition increased As adsorption by BSC from 51.2% to 83.0% but reduced Cd adsorption from 73.2% to 50.3%, whereas urea inhibited As uptake but enhanced Cd capture. Under co-contamination, the As removal ability of the BSC remained unchanged, but Cd removal improved. As was primarily present in the non-EDTA exchangeable fraction (79.0%), which increased to 96.4% and 85.8% in the presence of Fe/Mn, and urea, respectively. Cd was mainly in the sorbed fraction (51.6%), which increased to 61.0% with urea. These results confirm that BSC exhibits a strong ability to adsorb As and Cd under irrigated water with combined As and Cd contamination, iron/manganese and urea can also enhance this ability. The application of exogenous Fe/Mn providing the raw material for the mineralization process and the presence of urea enhancing the biological activity of the colonies. This study provides an eco-friendly strategy for remediating As and Cd in paddy fields. Full article

Active biomonitoring of mercury (Hg) using non-indigenous moss bags was performed for the first time within and around the former Hg mining area of Abbadia San Salvatore (Mt. Amiata, central Italy). The purpose was to discern the Hg spatial distribution, identify the most polluted areas, and evaluate the impacts of dry and wet deposition on mosses. The exposed moss bags consisted of a mixture of Sphagnum fuscum and Sphagnum tenellum from an external uncontaminated area. In each site, two different types of moss bags, one uncovered (to account for the wet + dry deposition) and one covered (to evaluate the dry deposition), were exposed. The behavior of arsenic (As) and antimony (Sb) in the mosses was investigated to assess the potential relationship with Hg. GEM (Gaseous Elemental Mercury) concentrations were also measured at the same sites where the mosses were exposed, although only as a reference in the initial stages of biomonitoring. The results revealed that the main Hg emissions sources were associated with the former mining area of Abbadia San Salvatore, in agreement with the measured GEM concentrations, while arsenic and antimony were related to soil enriched in As-Sb waste material. The three elements registered higher concentrations in uncovered mosses with respect to the covered ones, i.e., wet deposition was the key factor for their accumulation on the uncovered mosses, while dry deposition was especially important for the covered samples in the mining area. Hg was accumulated in the mosses via GEM adsorption, uptake of particulate Hg, and precipitation via raindrops/snowfall, with almost no loss and without post-deposition volatilization. The results testified that the chosen biomonitoring technique was an extremely useful tool for understanding Hg transport and fate in a contaminated area. Full article