Environmental Science: Nano最新文献

Environmentally persistent free radicals (EPFRs) are a new class of pollutants that are stable and persistent in the environment and are mainly produced on particles or organics under heating or light irradiation. Aged micro- and nano-plastics (MNPs) are important sources of EPFRs. Existing reviews have focused particularly on the environmental and biological hazards of aged MNPs themselves. Few reviews have focused on the role of EPFRs on aged MNPs, let alone their fate in the environment and their positive applications. This review summarizes the factors that influence the occurrence and formation of EPFRs from aged MNPs, their types and decay periods in the environment, and their conversion into reactive species (RS). This article also discusses the environmental effects of EPFRs on the microbial community structure, the cycles of elements (C, N, Cl, S, and P), and the survival of microorganisms, plants, and animals in soil and water. Moreover, the biological effects of EPFRs from aged MNPs are discussed, including oxidative stress, neurotoxicity, reproductive toxicity, respiratory toxicity, and their impact on aging. Meanwhile, the high reactivity of EPFRs can be harnessed to transform them into environmental protection warriors. Hence, the application of EPFRs in improving environmental pollution is also reviewed, including their use in fixing metals, degrading organic pollutants (including antibiotics and MNPs), and sterilization. Finally, this article provides insights for future research on the dual nature of EPFRs on aged MNPs. This review aims to mitigate the environmental and biological risks of EPFRs and provide a reference for their optimal application.

Arsenic (As) accumulation in soils is steadily rising, making it increasingly toxic to a variety of crop plants and humans. As reduces plant productivity by interfering with several molecular, biochemical, and morphological aspects of plant metabolism. Therefore, introducing new agents to address these issues is imperative. This study demonstrates the effective use of nano-biochar (nano-BC) to mitigate As stress toxicity in Glycine max (soybean) plants. We determined the effect of nano-BC (1% w/w) on mitigating As (50 μM) stress in soybean by examining various growth parameters and metabolic attributes. As stress inhibited plant height (by 51%) and net photosynthetic rate (by 50%) and caused the buildup of reactive oxygen species (ROS); however, nano-BC treatments significantly reversed all these parameters. Moreover, the As stress increased malondialdehyde (by 78%) and hydrogen peroxide (by 67%), which were partially reversed by nano-BC in the As-treated plants. This outcome may be attributed to activation of the plant defense response, particularly antioxidants, triggered by nano-BC. Overall, As tolerance in soybeans was positively regulated by nano-BC. However, additional research is required to fully understand the intricate mechanisms behind nano-BC and its defense mechanism against As.

The increasing release of anthropogenic volatile organic compounds (VOCs) and toxic gases (TGCs) has become a key environmental concern. The quest to address the complex capture challenges for VOCs/TGCs removal calls for innovative, advanced, highly efficient and sustainable materials. A straightforward, one-step, low-cost, sustainable and scalable technique was used for the synthesis of a nitrogen-doped graphene aerogel (N-GA) from waste jaggery with a 3D interconnected network, super-hydrophobicity, and a high surface area. The efficiency of waste jaggery derived N-GA as a multifunctional adsorbent for VOCs/TGCs under ambient conditions is investigated in both gaseous and liquid states in a reversible manner. The N-GA realizes the adsorption-based capture of diverse TGCs/VOCs such as dichloromethane (DCM), H₂S, CS₂, benzene and NH₃ with adsorption capacities of over 1226, 1002.07, 885.58, 792.9, and 489.4 mg g⁻¹, respectively, with high regeneration capability over 10 cycles. The feasibility of N-GA for the removal of organics in an aqueous medium has also been investigated for diverse organic solvents. This is relevant to direct application in indoor/outdoor air purification technologies, water remediation and ecosystem protection.

Iron (oxyhydr)oxides (FeO) significantly influence the environmental dissemination of antibiotic resistance genes (ARGs) by adsorbing ARG-carrying DNA through phosphate interactions. However, the fate of FeO-adsorbed DNA, particularly its release dynamics and impact on ARG dissemination in the presence of inorganic phosphate with environmentally relevant concentrations (Pi_e), remains unclear. Using goethite (a representative FeO mineral) and diverse DNA forms (three linear fragments, one ARG-carrying plasmid), this study quantified Pi_e-driven DNA desorption via a novel successive desorption–extraction protocol, distinguishing readily desorbable DNA from residual DNA. Pi_e (1.0–10 mg P L⁻¹) displaced 5–96% of adsorbed DNA. Structurally, the shorter linear DNA and supercoiled plasmid formed fewer Fe–O–P bonds per adsorbed molecule, enhancing Pi_e-driven displacement and subsequently increasing their desorbable fraction, yielding a two-stage response to Pi_e fluctuations (minimal below 0.2–0.5 mg P L⁻¹; substantial above). Critically, Escherichia coli transformation assays showed that while goethite adsorption suppressed ARG transfer, Pi_e-activated desorption restored transformation efficiency. These results resolve the unverified link between realistic Pi_e fluctuations (e.g., paddy field fertilization/sediment hydrology) and FeO-bound DNA release, demonstrating its potential role in ARG dissemination. This mechanistic insight is essential for risk assessment of ARG transmission in iron-rich ecosystems and strategic deployment of FeO materials for soil ARG mitigation.

The potential environmental risks of two-dimensional (2D) phosphorene nanomaterials are gaining attention as their promising applications continue to expand. Violet phosphorus (VP) has been demonstrated to be a more stable phosphorene nanomaterial compared to black phosphorus (BP). However, current research has primarily focused on the toxic effects of BP, with limited information available regarding the toxicity of VP. This study comparatively analyzed the ecotoxicity and mechanisms of action of environmentally relevant concentration exposures of the common green algae Tetradesmus obliquus to BP and VP nanosheets. The results revealed that VP exhibited a greater growth inhibitory effect on the algae compared to BP, which was linked to disruptions in cell membrane function. Both BP and VP induced intracellular oxidative stress responses, yet they did not cause oxidative damage to algal cells. Transcriptional responses suggested that the number of differentially expressed genes in the algae exposed to VP was 29 times higher than that in the algae exposed to BP. Metabolomic analysis indicated that the number of differentially expressed metabolites induced by VP exposure in the algae was twice as high as the changes induced by BP. Furthermore, integrated transcriptome and metabolome analyses highlighted significant differences between BP and VP in core pathways, key metabolites, and driving genes. The findings of this study underscore the importance of considering the impact of different types of phosphorene materials when assessing their environmental risks.

Cadmium (Cd) contamination in rice causes severe health hazards and compromises food safety; therefore, it is crucial to minimise Cd toxicity. In the present study, a novel green-synthesized Fe–Zn bimetallic nanoparticle (Fe–Zn BNP) was evaluated for Cd remediation and growth-promoting potential. Fourteen day-old indica rice seedlings were co-treated with 10 μM CdCl₂ and Fe–Zn BNPs (25 mg L⁻¹) for seven days and assessed for growth, stress parameters, and Cd content. Results indicated that Fe–Zn BNPs could effectively restore impaired growth parameters (root, shoot length, fresh and dry weight) and elevate chlorophyll and its precursor molecules (δ-ALA and PBG), eventually increasing photosynthetic efficiency by 72.21%. Significant reduction of ROS formation and other stress markers (MDA, methylglyoxal) were also observed. This study revealed a significant increase in Fe and Zn content upon treatment of Cd-stressed seedlings with Fe–Zn BNPs. Fe–Zn BNPs were found to restrict Cd localisation in root apices and reduce translocation from the root to the shoot by phytochelatin-mediated Cd sequestration (32.38% in the shoot and 42.39% in the root). Simultaneously, Fe–Zn BNPs downregulated the expression of Fe and Zn transporter genes OsIRT1, OsZIP1, and OsZIP4. Therefore, this research offers a promising avenue for the efficient amelioration of Cd toxicity in rice and improved plant health by developing a novel BNP.

The increasing exposure of engineered nanomaterials (ENMs) in agriculture, whether intentional or unintended, has led to growing concerns about their long-term biological impacts. While short-term nanomaterial exposure effects have been extensively studied, the multigenerational effects and potential transgenerational inheritance remain poorly understood. Here, we systematically investigated the biological effects of long-term nanomaterial exposure across multiple plant generations using Arabidopsis thaliana as a model system. Five chemically distinct nanomaterials (carbon dots, SiO₂, TiO₂, Fe₃O₄ and graphene oxide) were applied through root exposure for five consecutive generations (T₁–T₅), followed by a nanomaterial-free recovery generation (T₆). Whole-genome sequencing revealed no detectable genetic alterations in ENM-parental-exposed T₆ plants compared to the parental-unexposed T₆ control ones. Strikingly, transcriptional profiling found significant changes in gene expression, and the expression differences almost align with the phenotypic traits observed in the nanomaterial-treated T₁ generation. Phenotypic traits, such as enhanced biomass accumulation originally induced in T₁–T₅ generations persisted in T₆ plants despite nanomaterial withdrawal, suggesting the occurrence of transgenerational memory. Our findings provide the first experimental evidence that multigenerational exposure to these five nanomaterials induces no detectable genetic alterations but transgenerational memory in Arabidopsis thaliana, offering new insights for sustainable nano-agriculture development.

From an ecological risk perspective, it is important to differentiate engineered nanoparticles (ENPs) from naturally occurring nanoparticles (NNPs). The aim of this research was to characterize and quantify titanium dioxide and zinc oxide nanoparticles (NPs) that were released from two commercial sunscreens into three aqueous matrices (ultrapure, hard and soft natural waters) after two short term exposures: ∼15 min and ∼60 min. An inductively coupled plasma time-of-flight mass spectrometer (ICP-ToF-MS) was used to detect elements with mass to charge (m/z) ratios ranging from 26 to 210 amu within single particles (SP). The elemental compositions, mass distributions and isotopic ratios (⁴⁷Ti/⁴⁹Ti and ⁶⁶Zn/⁶⁸Zn) of the individual NPs were investigated in order to determine to what extent it was possible to discriminate the natural and engineered NPs. The coupling of an ion-exchange resin to the ICP-ToF-MS resulted in a reduced background signal for zinc, leading to the detection of reasonably small zinc oxide nanoparticles (size detection limit of ∼53 nm on the ICP-ToF-MS). For both commercial sunscreens, Zn was primarily released as dissolved forms, with nearly all of the Zn found below the size detection limits or adsorbed to NNPs after 60 minutes. Based upon the SP-ICP-ToF-MS results, the detected NPs in the sunscreens mainly contained single elements, in contrast with the natural NPs. Elemental ratios were helpful to distinguish the ENPs from NPs, but isotopic ratios (Ti or Zn) were not a distinguishing factor for the NPs, in this case. Spearman rank analysis provided an additional index to distinguish the different particle types.

Biodegradable plastics have been widely used to reduce pollution from conventional plastics, but the harsh conditions of their degradation make them equally capable of generating nanoplastic (NP) pollution and producing interactive ecotoxicity by coexisting with various pollutants. In this paper, the interactive toxicity of polystyrene (PS)-NPs and polylactic acid (PLA)-NPs with the typical organic UV filters butyl methoxydibenzoyl methane (BM-DBM) on the intestinal health and metabolism of zebrafish (Danio rerio) was investigated at the tissue and molecular levels using wild AB zebrafish as a model organism. The results showed that both NPs and BM-DBM exposure alone or in combination induced different degrees of inflammatory symptoms in the zebrafish intestine, where PS and PS+B exposure groups also induced an imbalance of the zebrafish intestinal flora, causing a more severe intestinal inflammatory response than PLA and PLA+B. PS and PS+B also induced more metabolic pathways or differential metabolite alterations than PLA and PLA+B, respectively. The results of liver-related factor response showed that all exposure groups except PLA alone induced oxidative stress in liver tissue, and hepatic metabolic factors were also interfered with to varying degrees, with more severe organismal metabolic abnormalities induced in the PS and PS+B groups. The above reflected the liver friendliness of PLA, while highlighting the risk of hepatotoxicity of PS. Pearson correlation analysis proved that abnormal changes in metabolites such as lipids and lipid-like molecules due to changes in intestinal flora are most likely an important mechanism and cause of the abnormal response of intestinal and hepatic molecular indicators. We hope that our study will provide a basis for the ecological risk assessment of non-/biodegradable NPs and provide data support for the promotion of biodegradable plastics.

Carbon dots (CDs) have shown advancement in scavenging radicals. However, the potential structure–function relationship is still unclear. Here, four kinds of CDs rich in carboxyl (CDs-c), hydroxyl (CDs-h), and different contents of amino structures (CDs-a_0.2, CDs-a_2), respectively, were prepared by regulating the raw reagent using a microwave assisted method. In vitro assays indicated that CDs-c had the highest scavenging activities against KMnO₄, DPPH, ·OH, and O₂⁻ radicals. The changes in the morphology and chemical structure of these CDs after the reaction with ·OH suggested that the carboxy-like structures play significant roles in radical scavenging and antioxidant activity. Additionally, the calculation of reaction energy barriers using density functional theory (DFT) revealed that the interaction between the carboxyl group and free radicals occurred in a barrier-free manner, resulting in the highest radical scavenging activity. In subsequent hydroponic experiments, rice seedlings pre-treated with CDs-c showed the highest activity in their antioxidant defense system (SOD: 13.13%; POD: 40.55%; CAT: 133.33%; flavonoid: 6.93%) and a significant enhancement in resistance to salt stress (fresh weight: 14.16%; height: 26.90%; chlorophyll content: 12.74%). This study uncovered the key active structures and mechanisms of CDs to scavenge oxidative radicals for plant antioxidant capacity under stress conditions and contributed to the management of environmental challenges faced by agriculture.